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Design of a Pneumatic Lifting DeviceComparison of Pneumonia Management Methods

Abstracts The incentive of this project is to provide an alternative method for lifting heavy weight vehicles in the range of 2 tons by means of designing a pneumatic lifting device, where compressed air contrived through a compressor is the main source of providing lift to the vehicle.  Furthermore, the objective of this final year project is to add further functionality to existing heavy weight lifters, by allowing manoeuvrability of the

INTRODUCTION

1.1 Background:

Pneumonia is the inflammation and consolidation of lung tissue due to an infectious agent (Marrie TJ, 1994). Pneumonia has the highest mortality rate among infectious diseases and represents the fifth leading cause of death (Brandstetter, 1993). Pneumonia causes excess morbidity, hospitalization, and mortality, especially among the elderly, the fastest growing sector of the population.According to first- or second-listed diagnosis, approximately 1 million persons were discharged from short-stay hospitals after treatment for pneumoniain the United States in 1990, and elderly persons aged 65 years or more accounted for 52% of all pneumonia discharges (Fedson & Musher, 1994). Pneumonia has the highest mortality rate among infectious diseases and represents the fifth cause of death (Brandstltter, 1993). In addition fine (2000) reported that lower respiratory tract infections affect three million persons annually and is the leading cause of death of infection in the United States.

• Pneumonia represented one of the 10th leading causes of hospitalization and deaths in Malaysia through 1999-2006 (Ministry of Health, Malaysia, 1999, 2000, 2001, 2002b, 2003, 2004, 2005band 2006b)

Because of differences in pathogenesis and causative micro-organisms, pneumonia is often divided into: hospital acquired and community-acquired pneumonia.Community acquired pneumonia (CAP) is caused mainly by streptococcus pneumoniae. Its symptoms include coughing (with or without sputum production), change in colour of respiratory secretion, fever, and pleuritic chest pain (Fine, 2000). Nosocomial pneumonia or hospital acquired pneumonia is the second most common nosocomial infection in the United States and it causes the highest rates of morbidity and mortality. It is caused mainly by streptococcus pneumoniae and pseudomonas aeruginosa. The highest mortality rates occurred in patients with pseudomonas aeruginosa or acineobacter infection. It is characterized by fever and purulent respiratory secretion. Nosocomial pneumonia results in increase length of hospitalization and cost of treatment (Kashuba, 1999; Levison, 2003; Wilks et al., 2003). The clinical criteria for the diagnosis of pneumonia include chest pain, cough, or auscultatory findings such as rales or evidence of pulmonary consolidation, fever or leucocytosis. In addition, there must be radiographic evidence, such as the presence of new infiltrates on chest radiograph, and laboratory evidence that supports the diagnosis. Because of differences in pathogenesis and causative micro-organisms, pneumonia is often divided in hospital acquired and community-acquired pneumonia. Pneumonia developing outside the hospital is referred to as community-acquired pneumonia (CAP).

Pharmacoeconomic study

Pharmacoeconomics is defined as the description and analysis of costs of drug therapy or clinical service to health care systems and society (Bootman et al., 1996). It has risen up as the discipline with the increase interst in calculating the value and costs of medicines (Sanches, 1994). Cost is defined as the value of resources consumed by the program or drug therapy of interest while a consequence is defined as the effect, outputs, or outcomes of a program. When identifying the costs associated with a product or service, all possible costs that include or related to the study are calculated (Sanchez, 1994). With the increase in financial pressure to hospitals to minimize their medical care costs, pharmacoeconomics can define costs and benefits of both expensive drug therapies and pharmacy based clinical services (Destache, 1993; Touw, 2005).Furthermore pharmacoeconomics can assist practitioners in balancing cost and quality that may result in improving patient care and cost saving to the institution (Sanches, 1994). Bootman and Harison (1997) stated that pharmacoeconomics and outcome research are very important to determine the efficient way to present a quality care at realistic rate. They suggested that pharmacoeconomics should have a remarkable authority on the delivery and financing of health care throughout the world.

Different methods have been used to perform pharmacoeconomics analysis which includes:

Cost-benefit analysis:

Cost-benefit analysis two or more alternatives that do not have the same outcome measures. It measures all costs and benefits of a program in monetary terms (Bootman et al., 1996; Fleurence, 2003). Cost-benefit analysis could play a major role in identifying the specific costs and benefits associated with the pneumonia.

Cost-effective analysis

Cost-effective analysis compares alternatives that differ in safety, efficacy and outcome. Cost is measured in monetary terms, while outcome is measured in specific objectives or natural units. The outcome are expressed in terms of the cost per unit of success or effect (Bootman et al., 1996).

Cost-utility analysis

Cost-utility analysis compares treatment alternatives; benefits are measured in terms of quality of life, willingness to pay, and patient preference for one intervention over another, while cost is measured in monetary terms. It has some similarity to cost-effectivness with more concentration on patient view. As an example, looking for new druig therapy; benefits can built-in together with expected risks.

Cost-minimization analysis

Cost-minimization analysis is one of the simplest forms of pharmacoeconomics analysis. It is used when two or more alternatives are assumed to be equivalent in terms of outcomes but differ in the cost which is measured in monetary terms (Fleurence, 2003).

Cost of illness analysis

Cost of illness analysis is the determination of all costs of aparticular disease, which include both direct and indirect costs. Since both costs were calculated, an economic evaluation for the disease can be performed successfully. It has been used for evaluating many diseases (Bootman et al., 1996).

1.2 Study problems and rationale

  • The management of pneumonia is very straight forward. However this is not always true for the diagnosis and selection of therapy. As there are some issues related to pneumonia that need to be addressed :
  • The first issue pertains to the inappropriate diagnosis of the pneumonia. Some physicians do not properly identify the causative organism, I.e, whether, it is bacterial or viral.
  • Bartlet et al (1998) found that the viral infections have been associated with at least 10% to 15 % of CAP in hospitalized adults (Bartlet et al, 1998).
  • Secondly is the use of inappropriate medications. The prescription of inappropriate or un-indicated drug therapy such as the prescription of antibiotics for pneumonia caused by nonbacterial infection may increase the incidence of bacterial resistance (Steinman, 2003).
  • Thirdly the adherence to guidelines improves quality of care and reduces the length of hospital stay (Marrie TJ et al, 2000).
  • Fourthly the adherence to guidelines reduces the cost of treating pneumonia (Feagan BG, 2001).
  • Fifthly Teaching hospitals are widely perceived to provide good outcome, and that reputation is thought to justify these institutions’ comparatively higher charges relative to non-teaching (general) hospitals. Despite their reputation for specialized care, teaching hospitals have traditionally relied on revenue from routine services, such as treatment of pneumonia, and the costs of specialized services and medical training. However, with managed care and competition creating pressures for cost containment, these higher costs have come into question:
  • Do a teaching hospital provide good outcome for management of pneumonia, or do a general hospital provide comparable outcome at lower costs?

1.3 Significance of the Study

This study has the following important issues:

To the researchers:

  • Several studies have compare the management of pneumonia in a university hospital versus a general hospital, but most of these studies were conducted in the USA and other parts of the world. There are no published studies in Malaysia or Asia to our knowledge.
  • This study also provides the difference in the outcome, cost and cost-effectivness of treating pneumonia between a university hospital and a general hospital.

To the practitioners:

  • This study will provide information about the adherence to guidelines will reduce the length of hospital stay, reduce the cost of treating pneumonia and improve outcomes of treating pneumonia.

To the patients:

  • This study attempts to highlight the benefits associated with adherence to the guidelines.

To the policy makers:

  • This study will help policy makers to develop new strategies for management of pneumonia.
  • This study will help policy makers to develop new guideline for management of pneumonia according to the microorganisms and the population in Malaysia.
  • This study also provides the difference in the management of pneumonia between a university hospital and a general hospital.
  • This study will provide information about how we can reduce the length of hospital stay, reduce the cost of treating pneumonia and improve outcomes of treating pneumonia.
  • The results of this study will help in improving the management of pneumonia.
  • It is the time to know whether a university hospital (H-USM) provide good outcome for treating pneumonia or do a general hospital (Penang-GH) provide comparable outcome at lower costs.
  • By analyzing the cost and effectiveness of the regimens being used, the most effective therapy can be defined and the information can be offered to the policy makers to improve the deciosion making in treating pneumonia.

The study will be able to help on:

  • How we can make the drug therapy cost effective keeping effectiveness and outcome in our mind and try to suggest the best and most appropriate drug therapy which should be cost effective which help to decrease the financial burden on patients as well as Ministry Of health.
  • This study will help to suggest how we can reduce the cost of therapy of treating pneumonia.

The study will be able to provide data on:

  1. The incidence of pneumonia in (H-USM and Penang-GH).
  2. The most common organisms causing pneumonia in (H-USM and Penang-GH).
  3. The pattern of drugs used and management of pneumonia in in (H-USM and Penang-GH).
  4. The outcome of treating pneumonia in (H-USM and Penang-GH).
  5. The cost of treating pneumonia in (H-USM and Penang-GH).
  6. The cost-effectivness of treating pneumonia in (H-USM and Penang-GH).
  7. Whether a university hospital provide a good outcome for management of pneumonia, or a general hospital provide comparable quality at lower costs.

1.4 Hypothesis of the Study:

  • H0: There is no significant difference of the management of pneumonia between a universiry hospital (H-USM) and a general hospital (Penang-GH).
  • H1: There is a significant difference of the management of pneumonia between a universiry hospital (H-USM) and a general hospital (Penang-GH).

1.5 Aim of the study

The aim of this study is to compare the management of pneumonia in a university hospital (H-USM) versus a general hospital (Pinanag-GH).

1.6 Objectives

The objectives of this study are:

  • To compare the incidence of pneumonia at a university hospital (H-USM) versus a general hospital (Penang-GH).
  • To compare the most common organisms associated with pneumonia at a university hospital (H-USM) versus a general hospital (Penang-GH).
  • To compare the drug therapy for pneumonia at a university hospital (H-USM) versus a general hospital (Penang-GH).
  • To compare the outcome of treating pneumonia (mortality rate, length of hospitalization, pneumonia related symptoms at discharge and complications of pneumonia) at a university hospital (H-USM) versus a general hospital (Penang-GH).
  • To compare the cost of treating pneumonia at a university hospital (H-USM) versus a general hospital (Penang-GH).
  • To compare the cost-effectivness of treating pneumonia at a university hospital (H-USM) versus a general hospital (Penang-GH).

1.7 Research Questions

  • What are the difference between the organisms that is commonly associated with pneumonia at H-USM and Penang-GH?
  • What are the difference between the antibiotics that is commonly used for the treatment of pneumonia at H-USM and Penang-GH?
  • What are the difference between the outcome of treating pneumonia (mortality rate, length of hospitalization, pneumonia related symptoms at discharge and complications of pneumonia) at H-USM and Penang-GH?
  • What are the difference between the cost of treating pneumonia at H-USM and Penang-GH? And how can these costs be reduced?
  • What are the difference between the cost-effectivness of treating pneumonia at H-USM and Penang-GH?
  • Do a university hospital (H-USM) provide good outcome for treating pneumonia or do a general hospital (Penang-GH) provide comparable outcome at lower costs?

CHPTER 2

LITERATURE REVIEW

2.1 Community-acquired pneumonia

2.1.1 Introduction

Community-acquired pneumonia (CAP) is defined as an acute infection of the pulmonary parenchyma that is associated with at least some symptoms of acute infection, a new infiltrate on chest x-ray or auscultatory findings such as altered breath sounds and/or localized rales in community-dwelling patients (Infectious Diseases Society of America 2000). It is a common condition that carries a high burden of mortality and morbidity, particularly in elderly populations. Although most patients recover without sequellae, CAP can take a very severe course, requiring admission to an intensive care unit (ICU) and even leading to death. According to US data, it is the most important cause of death from infectious causes and the sixth most important cause of death overall (Adams et al. 1996). Even though the mortality from pneumonia decreased rapidly in the 1940s after the introduction of antibiotic therapy, it has remained essentially unchanged since then or has even increased slightly (MMWR 1995). Furthermore, significant costs are associated with the diagnosis and management of CAP. Between 22% and 42% of adults with CAP are admitted to hospital, and of those, 5% to 10% need to be admitted to an ICU (British Thoracic Society 2001). In the US, it is estimated that the total cost of treating an episode of CAP in hospital is about USD $ 7500, which is approximately 20 times more than the cost of treating a patient on an outpatient basis (Lave et al. 1999). CAP also contributes significantly to antibiotic use, which is associated with well-known problems of resistance. In treating patients with CAP, the choice of antibiotic is a difficult one. Factors to be considered are the possible etiologic pathogen, the efficacy of the substance, potential side-effects, the treatment schedule and its effect on adherence to treatment as well as the particular regional resistance profile of the causative organism and the co-morbidities that might influence the range of potential pathogens (such as in cystic fibrosis) or the dosage (as in the case of renal insufficiency). It may be a primary disease occurring at random in healthy individuals or may be secondary to a predisposing factor such as chronic lung disease or diabetes mellitus. CAP represents a broad spectrum of severity, ranging from mild pneumonia that can be managed by general practitioners outside the hospital to severe pneumonia with septic shock needing treatment in intensive care unit. Depending on severity of illness, about 20% of patients with pneumonia need hospitalization and approximately 1% of all CAP patients require treatment in ICU. Elderly persons and those with underlying conditions, such as cerebro and cardiovascular diseases, chronic obstructive pulmonary disease (COPD) and alcoholism, are at increased risk for developing lower respiratory tract infections and complicated courses of infection.

2.1.2 Definition:

Community-Acquired pneumonia (CAP) is defined as inflammation and consolidation of lung tissue induced by infectious microbes such as bacteria, viruses, or parasites. When the onset of symptoms and signs of this disease is before or within 48 hours after admission, it is considered as CAP (Bartlett JG et al., 1995).

2.1.3 Epidemiology & Incidence:

In the industrialized world, the annual incidence of CAP in community dwelling adults is estimated at 5 to 11 cases per 1000 adult population (British Thoracic Society 2001). The incidence is known to vary markedly with age, being higher in the very young and the elderly. In one Finnish study, the annual incidence for people aged 16-59 years was 6 cases per 1000 population, for those 60 years and older it was 20 per 1000, and for people aged 75 and over, 34 per 1000 (Jokinen et al. 1993). Annual incidences of 30-50 per 1000 population have been reported for infants below 1 year of age (Marrie 2001). Seasonal variations in incidence are also significant, with a peak in the winter months (Marrie 2001). The annual incidence of CAP requiring hospitalisation has been estimated at 1 to 4 patients per 1000 population (Marrie 1990, Fine et al. 1996). The proportion of patients requiring hospitalisation varies from country to country and across studies and has been estimated as ranging anywhere between 15% and 56% (Foy et al. 1973, Minogue et al. 1998). Of those, 5% to 10% required admission to an intensive care unit (ICU) (British Thoracic Society Research Committee and Public Health Laboratory Service 1992, Torres et al. 1991). Conversely, about 8% to 10% of admissions to a medical ICU are due to severe CAP (Woodhead et al. 1985). Community acquired pneumonia (CAP) is a leading infectious disease cause of death throughout the world (WHO Statistical Information System (WHOSIS). WHO Mortality Database. Released: January 2005; Health, United States, 2005; Annual Report, Hong Kong, 2003/2004).

Adult community-acquired pneumonia is a serious, life-threatening illness that affects more than 3 million people each year and accounts for more than half a million annual hospital admissions in the United States alone (Lynch JP, 1992).

Each year, more than 900 000 cases of pneumonia occur in the United States, accounting for nearly 3% of all hospital admissions,(National Hospital Discharge Survey, 1988) and about 50 000 people die as a result of community-acquired pneumonia (Farr BM et al 203).

Bartlet et al (1998) found that viral infections have been associated with at least 10% to 15 % of CAP in hospitalized adults.

Adult community-acquired pneumonia is a serious, life-threatening illness that affects more than 3 million people each year and accounts for more than half a million annual hospital admissions in the United States alone.

Each year, more than 900 000 cases of pneumonia occur in the United States, accounting for nearly 3% of all hospital admissions, and about 50 000 people die as a result of community-acquired pneumonia. In the USA, community acquired pneumonia is the fifth leading cause of death in people over the age of 65 years and an estimated 60 000 seniors die annually. Most of the excess deaths and hospitalizations due to lower respiratory infections occur in older adults, as reflected by the more than 44 000 hospitalizations for pneumonia and influenza in people aged 65 and older in 1997 in Canada. It is estimated that the age-specific incidence of pneumonia increases from 15.4 cases per 1000 in those aged 60-74 years to 34.2 for those 75 years and older. Residents of long-term care facilities, a distinct subpopulation of elderly people, are at particularly high risk for developing nursing-home acquired pneumonia. Health costs for this sector are growing at an accelerated rate as the age of death increases. Thirteen percent of the population is over the age of 65 in the United States and this is expected to increase to 20% by 2030. In Canada, the proportion of individuals over the age of 65 is expected to rise to 20% in the year 2021. Presently, while making up 12% of the Canadian population, older adults account for 31% of acute hospital days and half of all hospital stays. To meet their health-care needs and alleviate the burden onthe health-care system, we must improve our understanding of the management and prevention of pneumonia in this age group. Elderly people constitute an ever-increasing proportion of the population. CAP has traditionally been recognized as problems that particularly affect the older individuals. According to western studies, the overall rate of pneumonia requiring hospitalization increase with age, from 1 per 1,000 persons in the general population but increases to 12 per 1,000 persons for those over age 75 years3. As the population of those over age 65 years is predicted to rise from its current level of 11% to 25 % of the total population in the year 20504, respiratory tract infection will assume a greater degree of importance to the overall public health. In Hong Kong, pneumonia was the fourth leading death from a specific diagnosis in 2001. A total of 3026 people died of pneumonia in 2001 which 1526 cases were male. Out of the 3026 deaths, 2794 patients were 65 or older which accounted for more than 90% of the total death. Pneumonia in the elderly population is a major cause of morbidity and mortality and in some series represents the leading cause of death. The annual cost of treating patients age > 65 years with pneumonia to be $4.8 billion, compared with $3.6 billion for those < 65 years with pneumonia. The average hospital stay for an elderly person with pneumonia was 7.8 days, at cost of $7166, whereas for a younger patient the corresponding values were 5.8 days and at cost of $6042. Global mortality of the elderly patients hospitalized for CAP was 9.8% – 29%H’14. The cause of the death was attributed to acute respiratory failure (37%), septic shock and/or multiple organ failure (63%). Recovery is also prolonged in the elderly, especially the frail elderly who may require up to several months to return to their baseline state of mobility. Indeed, hospitalization often hastens functional decline in the elderly. 25-60% of elderly patients experience a loss of independent physical function during hospitalization. Twenty-one percent of those aged >85 years need help with bathing and 10% need help in using the toilet and transferring. The present of any or all of following identifies elderly persons at greatest risk for functional decline: pressure ulcer, cognitive impairment, functional impairment, and low level of social activity. The attack rate for pneumonia is highest among those in nursing homes. It is found that 33 of 1,000 nursing home residents per year required hospitalization for treatment of pneumonia, compared with 1.14 of 1,000 adults living in the community.

Pneumonia is a major cause of morbidity and mortality worldwide. In the UK as a whole, pneumonia is responsible for over 10% of all deaths (66,581 deaths in 2001), the majority of which occur in the elderly.

Community-acquired pneumonia (CAP) remains a common cause of morbidity. Because CAP also is a potentially fatal disease, even in previously healthy persons, early appropriate antibiotic treatment is vital. In Japan, pneumonia is the fourth leading cause of death, and from 57 to 70 persons per 100,000 populations died per year of this disease in the last decade.

Community acquired pneumonia (CAP) is a leading infectious disease cause of death throughout the world, including Hong Kong,

Pneumonia is the second most common infectious disease in Thailand. Whereas diarrhea is more common, pneumonia is associated with more fatalities.

CAP remains the leading cause of death due to infectious diseases, with an annual incidence ranging 1.6-10.6 per 1,000 adult populations in Europe

According to the Ministry of Health Malaysia (MOH), pneumonia is the 5th cause of death in Malaysia and the 4th cause of hospitalization.

A prospective observational study by Jae et al (2007) of 955 cases of adult CAP in 14 hospitals in eight Asian countries found that the overall 30-day mortality rate was 7.3%.

A prospective study by Liam CK et al (2001) of 127 cases of CAP in Malaysia found that the Mortality from CAP is more likely in patients with comorbidity and in those who are bacteraemic.

A prospective study by LOH et al (2004) of 108 cases of adult CAP in urban-based university teaching hospital in Malaysia found that the mortality rate from CAP in hospital was 12%.

2.1.4 Syndromes of CAP

The presence of various signs and symptoms and physical findings varies according to the age of the patients, therapy with antibiotics before presentation, and the severity of illness. Patients with pneumonia usually present with cough (>90%), dyspnea (66%), sputum production (66%% pleuritic chest pain (50%), and chills is present in 40-70% and rigor in 15%. However, a variety of nonrespiratory symptoms can also predominate in pneumonia cases, including fatigue (91%), anorexia (71%), sweating (69%), and nausea (41%).

Metlay et al. (1997c) divided 1812 patients with CAP into four age groups: 18 through 44 years (43%), 45 through 64 years (25%), 65 through 74 years (17%), and 75 years or older (15%). For 17 of the 18 recorded symptoms there were significant decreases in reported prevalence with increasing age (p <.01). For example, the prevalence of cough was 90% in the youngest age group and 84% in the oldest. Other symptoms that differ in prevalence in the youngest and oldest age groups, respectively, include dyspnea (75% and 64%); sputum production (64% and 64%); pleuritic chest pain (60% and 31%); hemoptysis (19% and 12%); fatigue (83% and 84%); fever (85% and 53%); chills (85% and 52%); anorexia (77% and 64%); sweats (83% and 2945%); headache (72% and 36%); myalgia (67% and 25%); nausea (48% and 31%); sore throat (45% and 27%); inability to eat (31% and 14%); vomiting (29% and 21%); diarrhea (29% and 21%); and abdominal pain (27% and 18%). Fine et al 1998 found that Hypothermia and hyperthermia were present in only 1% and 1.3% of the patients, respectively. About 80% of the patients had an oral temperature reading of >37°C at presentation. Crackles were present on auscultation in 80% of patients, and rhonchi in 34% to 47% (more common in the nursing home patients). About 25% had the physical findings of dullness to percussion, bronchial breathing, whispered pectoriloquy, and aegophony. Alteration in mental status was common. Marrie and coworkers (1989) reported confusion in 48% of the patients with nursing home-acquired pneumonia and in 30% of the other patients with CAP. Fine and colleagues (1998) define altered mental status as stupor, coma, or confusion representing an acute change from the usual state prior to presentation with pneumonia. This was present in 17.3% of the hospitalized patients. The decrease in symptoms with increasing age, tachypnea increased with increasing age (Metlay et al., 1997c). Thirty-six percent of 780 patients with CAP in the 18-44 year age group had tachypnea on admission versus 65% of the 280 patients who were = 75 years old. There were minimal differences in the proportion of patients with tachycardia and hyperthermia in the different age groups Pneumonia in the elderly are quite different from that in a younger population. These differences are due to age-related alterations in immunology, different epidemiology and bacteriology. It is important to remember that pneumonia in the elderly may report fewer respiratory signs and symptoms. The clinical presentation may be more subtle than in younger population, with more gradual onset, less frequent complaints of chill and rigors, and less fever. The classical finding of cough, fever, and dyspnea may be absent in over half of elderly patients8. Instead they may be manifest as delirium, a decline in functional status, weakness, anorexia, abdominal pain, or decrease general condition. The incidence of fever may decline with age, and the degree of fever appears lower in old population10. Tachypnea which respiration rate greater than 24-30 breaths per minute is noted more frequently in up to 69% of patients. Although rales are common and are noted in 78% of patients, signs of true consolidation are found in only 29%. Bacteremia, metastatic foci of infection and death are more frequent in older populations. As many elderly present with non-specific clinical symptoms and nonspecific functional decline that makes an accurate diagnosis difficult and may lead a life-threatening delay of diagnosis and therapy. Metlay et al. compared the prevalence of symptoms and signs of pneumonia in a cohort of 1812 patients and found that patients aged 65-74 years and over 75 years had 2.9 and 3.3 fewer symptoms, respectively, than those aged 18 through 44 years. The reduced prevalence of symptoms was most pronounced for symptoms related to febrile response (chills and sweats) and pain (chest, headache, and myalgia). These findings are consistent with those of Marrie et al. demonstrating reduced prevalence of non-respiratory symptoms among elderly patients. In a retrospective chart review by Johnson et al., the presence of dementia seemed to account for non-specific symptoms. However the sample size of the study was small and precluded a multivariable analysis. Roghmann et al found a significant inverse correlation between age and initial temperature in 320 older patients hospitalized for pneumonia. Evidence therefore does exist for a less distinct presentation of nonrespiratory symptoms and signs of pneumonia in the elderly.

2.1.5 Radiographic findings in CAP

Radiographic changes usually cannot be used to distinguish bacterial from nonbacterial pneumonia, but they are often important for diagnosis of CAP, evaluating the severity of illness, determining the need for diagnostic studies, and selecting antibiotic agents. A chest radiograph usually shows lobar or segmental opacification in bacterial pneumonias and in the majority of atypical infections. Patchy peribronchial shadowing or more diffuse nodular or ground-glass opacification is seen less commonly, particularly in viral and atypical infections. The lower lobes are most commonly affected in all types of pneumonia. Small pleural effusions can be detected in about one-quarter of cases. Multilobar pneumonia is a feature of severe disease, and spread to other lobes despite appropriate antibiotics is seen in Legionella and M. pneumoniae infection. Hilar lymphadenopathy is unusual except in Mycoplasma pneumonia, particularly in children. Cavitation is uncommon but is a classic feature of S. aureus and S. pneumoniae infections. False negative results can be attributed to dehydration, evaluation during the first 24 hours, pneumonia due to Pneumocystis carinii, or pneumonia with profound neutropenia.

2.1.6 Etiology:

More than 100 microorganisms have been identified so far as potential causative agents of CAP (Marrie 2001). They can be classified according to their biological characteristics as either bacteria, mycoplasma and other intracellular organisms, viruses, fungi and parasites. The most common causative agent of CAP is the bacteriumStreptococcus pneumoniae, which is implicated in 20% to 75% of cases of CAP (Marrie 2001) and about 66% of bacteremic pneumonia (Infectious Diseases Society of America 2000). Another causative bacterium is Haemophilus influenzae. So called “atypical” organisms have also been implicated as causal agents. These include Chlamydia pneumoniae, Mycoplasma pneumoniae and Legionella pneumophila (Marrie 2001). Influenza is the most common serio

thoroughly explained, along with the specifications and scope.  The selection of various parts for the design has been made with the product feasibility towards its functionality in mind.  It is vital to acknowledge that the selected parts have been able to meet with the design requirements. Keywords: DESIGN OF A PNEUMATIC ; LIFTING ; DEVICE ;

CONTENTS

LIST OF FIGURES LIST OF TABLES LIST OF SYMBOLS CHAPTER 1 INTRODUCTION 1.1 Introduction 1.2 Background 1.3 Objective 1.4 Scope 1.4.1 Selection of Pneumatic Motor 1.4.2 Selection of Lifting Mechanism 1.4.3 Manoeuvrability 1.5 Organization of Thesis CHAPTER 2 LITERATURE REVIEW 2.1 Introduction 2.2 Pneumatic Actuators 2.3 Pneumatic cylinder 2.4 Pneumatic Motor 2.4.1 Linear Pneumatic Motors 2.4.2 Rotary Pneumatic Motors 2.5 Pressure Regulators 2.5.1 Single Stage Regulator 2.5.2 Double Stage Regulator 2.6 Pressure Sensors 2.7 Types of Pressure Measurement 2.7.1 Absolute pressure sensor 2.7.2 Gauge pressure sensor 2.7.3 Vacuum pressure sensor 2.7.4 Differential pressure sensor 2.7.5 Sealed pressure sensor 2.8 History Of Pneumatics 2.8.1 Capsule Transportation 2.8.2 Postal Systems 2.8.3 Public Transportation 2.9 Vacuum Pumps 2.9.1 Positive displacement Pumps 2.9.2 Momentum transfer Pumps 2.9.3 Entrapment pumps 2.10 Comparison of Pneumatics to Hydraulics CHAPTER 3 METHODOLOGY 3.1 Introduction 3.2 Concept Generation 3.2.1 Concept 1: 3.2.2 Concept 2: 3.2.3 Concept 3: 3.3 PNEUMATIC MOTOR: 3.4 LOCOMOTION CHAPTER 4 RESULTS AND DISCUSSION 4.1 Introduction 4.2 Design Parameters 4.3 Component Parts                                                                                                         31 4.4 Final Design Parameters                                                                                           37 4.5 Calculation of Time and Velocity: 4.5.1 Time Required to Lift the Vehicle: 4.5.2 Time required for Horizontal Motion: 4.5.3 Velocity Provided By Vane Motor: 4.6 DISCUSSION CHAPTER 5 CONCLUSION AND RECOMMENDATION 5.1 Conclusion 5.2 Recommendations REFERENCES APPENDIX A: APPENDIX B: APPENDIX C:

LIST OF FIGURES

Figure 1.1 : Scope of research for pneumatic lifter Figure 1.2 : Scissors Lift Figure 2.1: Pneumatic lifter Figure 2.2: Pneumatic Actuator Figure 2.3: Pneumatic Actuator Figure 2.4: Radial Piston Pneumatic Motor Figure 2.5: Linear Pneumatic Motor Figure 2.6: Rotary Vane Motor Figure 2.7: One stage Regulator Figure 2.8: Two Stage Regulator Figure 3.1: Methodology Flowchart Figure 3.2: First Concept Figure 3.3: Second Concept Figure 3.4: Third Concept Figure 3.2: Vane Motor Figure 3.3 Top and side Mounts of Castor Wheels Figure 4.1:  Final Design Figure 4.2 : Stress Strain Analysis Figure 4.3: Pole Design Figure 4.4:  Upper Support Figure 4.5: Upper Support (Secondary Part) Figure 4.6: support for the car (part 1) Figure 4.7: support for the car (part 2) Figure 4.8: Locomotion Component

LIST OF TABLES

Table 4.1 : Specifications of Pneumatic Lifter Table 4.2: Specifications of Vane Motors Table 4.3: Specification of castors  

LIST OF SYMBOLS

RPM    Rotary Pneumatic Motor PR   Pressure Regulator DSR Double Stage Regulator PA   Pneumatic Actuator MTP  Momentum Transfer Pump EP   Entrapment Pump SPS   Sealed Pressure Sensor  

CHAPTER 1

INTRODUCTION

1.1 Introduction

This chapter delivers a general introduction on the topic studied. The research background and problem statement are concisely discussed in the first section. The following section lists the project objective and scope of project. The final section in this chapter presents the thesis organization and outline.

1.2 Background

In order to enhance the transfer of equipment so as to facilitate various vital procedures necessary for human development such as large scale construction, and manufacturing on large scale along with the ease of maintenance to both vehicles, and other machines, the proper designed equipment must be available in order to assure the ease and efficiency in the transfer, loading, and off loading of large weights.  Therefore, this project aims to aid in such operations by designing a product that can meet with these vital requirements, which is to design a pneumatic lifting device capable to lifting weights up-to 2 tons.  Hence, this is to be attained through the utilization of various software required or the design such as Pro/E along with the research undertaken on the matter, and knowledge gained from various literature reviews. This thesis thoroughly explores project undertaking, and explains the various phases of design that comprised of three phases. The first phase consists of searching the relevant information and various principles that go into designing devices capable of carrying excessively large weights, with regard to suitable design structure, materials used, and engineering dynamics that come into play in order to come up with a preliminary design. The second phase consists of utilizing the acquired knowledge and information gained from the preliminary design in order to attain an effective detailed design, along with the required analysis in order to prove it capability of successfully lifting weights of upto 2 metric tons.

1.3 Objective

The objective of this project is to successfully design a Pneumatic lifting device that is capable of efficiently and safely lift loads of up-to 2 metric tons and shift the load around.  The accomplished design should also be capable of lifting a vehicle off the ground in order to carry out underbody repairs.  Furthermore, a detailed stress analysis is to be carried out on the simulation software used in order to determine the safety factor of the design, thereby providing a product in which safe systems of work is developed and used for all lifting operations.  The risk assessment of the design work should take into account the working environment, geographical location etc where the equipment is to be used.

1.4 Scope

For this project, the design for heavy weight pneumatic lifter must be able to comply with the constraints set forward for this experiment.  Hence, the scope of research for pneumatic lifter Is divided into the following three sub-categorie: 

Pneumatic Lifter

Figure 1.1 : Scope of research for pneumatic lifter

1.4.1 Selection of Pneumatic Motor

The pneumatic motor acts as the main power source capable of providing lift to the design.  In this section, a pneumatic motor with precise specifications is selected for the required design. During the conceptual design phase, it was found that a pneumatic motor that is capable of providing sufficient power would suffice for the overall lightweight body of the design.    A massive motor was eliminated during the conceptual analysis phase as heavy designs were omitted for a more efficient, more practical compact design that requires a lot less powerful motor, hence adding to the practicality of the design. The selected motor however, should be capable of operating with high loading, and for the sake of safety, it should be able of successfully lifting a weight above the required 2 tons.

1.4.2 Selection of Lifting Mechanism

For this criterion, a unique alternative to the various hydraulic heavy weight lifting devices was opted for.  This was due to the fact that compressed air is a lot more unpredictable compared to uncompressible hydraulic fluid. Untitled:Users:macbook:Desktop:fourth year first sem:scissors-2.gif Figure 1.2 : Scissors Lift Therefore, the scissors concept of lift was opted for due to it’s ability of providing safety latches at every point of lift, thereby acting as an automatic brake in case of pneumatic motor failure and helping to eliminate dangerous or fatal accidents in the operation of this machinery [1].

1.4.3 Manoeuvrability

The obstacle of providing manoeuvrability to the design was overcome by the installation of heavy duty castors which was made possible after omitting heavy based designs that required excessive amount of energy for movement, to a more compact design that allows locomotion by the least exertion of energy by operator.

1.5 Organization of Thesis

This thesis is organized in the following order:

  • Chapter 1

A brief overview of pneumatic lifters in general and need for design of pneumatic lifter capable of lifting a 2-ton vehicle for undercarriage maintenance.

  • Chapter 2

A comprehensive summary on the various types of heavy weight lifting devices and mechanisms.

  • Chapter 3

Description of the design methodology and various parameters applied to designing the pneumatic heavyweight lifter.

  • Chapter 4

Contains explanation for the base calculation of the design and precise analysis of constructed parts of the pneumatic lifter

  • Chapter 5

Summarizes the result of the design selection and concludes the design of the pneumatic lifter.  This chapter also provides suggestion on future development of the current design.

CHAPTER 2

LITERATURE REVIEW

2.1 Introduction

This chapter discusses in detail, the present pneumatic technology available. The first section provides an overview of the functionality of pneumatics in general, along with their various applications.  Following sections describe the various principles relating to pneumatics, along with the benefits of using such systems.  Furthermore, a comprehensive research on various types of pneumatic motors, pistons, and sensors is clearly illustrated here. Pneumatic systems in fixed installations, such as factories, utilize compressed air since compressing atmospheric air can be a source of sustainable supply. The air regularly has moisture removed, and a small measure of oil is supplemented at the compressor in order to avoid corrosion and provide lubrication to the numerous mechanical constituents. One perceptible and valuable benefit in utilizing pneumatic-power for factory applications is that operators need not worry about poisonous leakages, due to the fact that the gas is ordinarily pure air. However, compressed gases that present an asphyxiation hazard, such as nitrogen—often referred to as OFN (oxygen-free nitrogen), could be used be smaller stand alone systems. Every compressed gas besides air is considered as a suffocation hazard—including nitrogen, which makes up to approximately 78% of air. Compressed oxygen (approx. 22% of air) would not lead to suffocation, but it is not utilized in pneumatically powered devices due to it being more expensive, a fire risk and offering no performance improvement over air. Handy pneumatic tools and small vehicles, the likes of Robot Wars machines are generally powered by compressed carbon dioxide, since containers that are devised to hold it such as fire extinguishers are easily accessible, and the phase change between liquid and gas makes it possible to obtain a larger volume of compressed gas from a lighter container than what is required by compressed air. Carbon dioxide is a suffocating agent and can be a freezing hazard if vented unfittingly. Pneumatic Lifters predominantly use pneumatic cylinders of low friction as source of lifting power and are capable of providing a cost effective solution to many lifting applications. Compared with vacuum lifting devices, pneumatic lifts are normally more suited to manual handling operations, which require precise or controlled pick and place movements, such as vehicle line-side operations in automotive plants.  Figure 2.1: Pneumatic lifter Pneumatic Lifters may utilize numerous pneumatic cylinder arrangements as the key power source, which would provide substantial lifting capabilities. Guided pneumatic lifters allow a solid mounting platform for tooling and the option of powered rotation in one or more axes. This design makes for particularly good drum handling equipment; where controlled movements prove beneficial to operators engaged in drum pouring or barrel tipping operations.

2.2 Pneumatic Actuators

A PA is a device that transforms energy (compressed air) into motorized movement. This motion can be either linear or rotary, depending on the type of pneumatic actuator used. The following are listed examples of pneumatic actuators:

  • Rotary actuators
  • Tie rod cylinders
  • Artificial Pneumatic muscles
  • Rod less actuators with mechanical linkage
  •  Rod less actuators with magnetic linkage
  • Grippers
  • Specialty actuators that combine rotary and linear motion—frequently used for clamping operations
  • Vacuum generators

A PA primarily contains a tube, ports and pistons. A seal keeps the air in the upper portion of the tube, thereby allowing air pressure to force the diaphragm downward, covers the piston moving the piston underneath, which in turn moves the valve stem that is linked to the internal parts of the actuator [2]. Depending on the type of action required, pneumatic actuators may have only one spot for a signal input. Valves need only slight pressure to function and normally double or triple the input force, therefore, the output pressure is directly proportional to the size of the piston. Thus, a larger piston can also be suitable if air supply is low, allowing the same forces with less input. A small pneumatic valve is capable of effortlessly lifting a vehicle (weighing approx. 500 kg) by applying only a 100 KPa input. However, the subsequent forces necessary of the stem would be too excessive and would eventually lead the valve stem to fail. Untitled:Users:macbook:Desktop:fig6.6.01.gif Figure 2.2: Pneumatic Actuator This pressure is transferred to the valve stem, which is hooked up to either the valve plug, butterfly valve etc. Larger forces are required in high pressure or high flow pipelines to allow the valve to overcome these forces, and allow it to move the valves moving parts to control the material flowing inside. Valves input pressure is the “control signal.” This can come from a variety of measuring devices, and each different pressure is a different set point for a valve [3]. A typical standard signal is 20–100 kPa. For example, a valve could be controlling the pressure in a vessel which has a constant out-flow, and a varied in-flow (varied by the actuator and valve). A pressure transmitter will monitor the pressure in the vessel and transmit a signal from 20–100 kPa. 20 kPas indicates and absence of pressure, where as 100 kPa indicates a full range pressure (varies with the transmitter’s calibration). With the rise in pressure within the vessel, an equal rise in the output of the transmitter occurs, this increase in pressure is sent to the valve, a result of which the valve forces a downward stroke, and proceeds to closing the valve, thereby reducing the pressure in the vessel as excess pressure is evacuated through the out flow. This process is called a direct acting process.

2.3 Pneumatic cylinder

Pneumatic cylinders (air cylinders) are mechanical devices that utilize the power retrieved from the compressed gas in order to yield a force in a reciprocating linear motion. As with hydraulic cylinders, pneumatic cylinders utilize the stored potential energy of a fluid, in this case compressed air, and convert it into kinetic energy as the air expands in an attempt to reach atmospheric pressure. This air expansion forces a piston to move in the desired direction. The piston is a disc or cylinder, and the piston rod transfers the force it develops to the object that is to be moved. Engineers prefer to use pneumatics sometime because they are quieter, cleaner, and do not require large amounts of space for fluid storage [4]. Untitled:Users:macbook:Desktop:sft2jpg_00000039022.jpg Figure 2.3: Pneumatic Actuator Because the operating fluid is a gas, leakage from a pneumatic cylinder will not drip out and contaminate the surroundings, making pneumatics more desirable where cleanliness is a requirement. For example, in the mechanical puppets of the Disney Tiki Room, pneumatics is used to prevent fluid from dripping onto people below the puppets.

2.4 Pneumatic Motor

A pneumatic motor (compressed air engine) is a motor that achieves mechanical work thru the expansion of compressed air. Pneumatic motors ideally utilize either rotary or linear motion for the conversion of compressed air to mechanical work. This linear motion is attained either from a piston or diaphragm actuator, where as the rotary motion is supplied by either a pneumatic vane motor or a pneumatic piston motor [5]. Untitled:Users:macbook:Desktop:027_series MA2 air motor.jpg Figure 2.4: Radial Piston Pneumatic Motor Over the past two centuries, Pneumatics has been present in a number of forms that ranged in size, from miniature turbines to engines capable of conjuring several hundred horsepower. A variety of compressed air engines increase their performance either by heating the incoming air, or the engine itself. Pneumatic have been extremely successful in the hand-held tool industry, and there have been constant attempts in expanding their use in the transportation industry. However, in order to be considered as a viable option in the transportation industry, these motors must overcome various inadequacies.

2.4.1 Linear Pneumatic Motors

So as to utilize compressed air in order to attain a motion that is linear in nature, it is uncommon that an arrangement of pistons to be use.  Air that is compressed is then pumped into a cavity that is airtight and contains the shaft of the piston.  Likewise, a coiled spring that surrounds the shaft is located within the cavity and keeps the compartment in an open position, in the event air is not fed into the chamber.  While air is pumped into the cavity, the force that is exerted on the spring is overcome by the force acting on the shaft of the piston. An increase of pressure occurs when the amount of air allowed into the cavity is increased as well.  This leads the piston to travel down the cavity [6]. Once its full length is attained, air pressure is discharged from the cavity, thereby allowing the spring to finish the cycle by means of shutting off the cavity in order to return to its initial position. Untitled:Users:macbook:Desktop:LinMotStainlessSteelLinearMotor.jpg Figure 2.5: Linear Pneumatic Motor Hydraulic systems primarily use piston motors, which are very similar to hydraulic pumps, except for the fact that they are utilized for translating hydraulic energy into mechanical energy.   Piston motors are often used in series of two, three, four, five, or six cylinders that are enclosed in a housing.

2.4.2 Rotary Pneumatic Motors

RPM (rotary vane motors), utilizes air in order to drive rotational motion to a shaft.  The rotating motion is attained by means of an instrument known as a slotted rotor that is fixed on a drive shaft. Every rotor gap has a freely slipping rectangular vane that is built-in. Depending on the design of the motor, air pressure, cam action, or springs are used in order to extend the vanes to the housing walls. The motor feeds compressed air in order to push the vanes, so as to attain a rotational motion of the central shaft [7]. The speeds of rotation can range from 100 to approx. 26,000 rpm, depending on the air pressure.     Figure 2.6: Rotary Vane Motor These motors are generally applied to operate immense natural gas or diesel or engines.  Stored energy in the form of compressed air, nitrogen or natural gas enters the sealed motor chamber and exerts pressure against the vanes of a rotor.  This causes the rotor to turn at high speed.  Reduction gears are used due to the fact that the engine flywheel requires a great deal of torque to start the engine. These reduction gears generate elevated levels of torque, with only a small amount of energy entered, which provides for adequate torque to be produced by the engine flywheel whilst being absorbed by the air motor’s pinion gear.

2.5 Pressure Regulators

The main function of PR is to match the flow of gas throughout the regulator to the demand for gas placed upon the system. If the load flow decreases, then the regulator flow must decrease also. If the load flow increases, then the regulator flow must increase in order to keep the controlled pressure from decreasing due to a shortage of gas in the pressure system [8]. A PR contains a restricting element, a loading element, and a measuring element:

  • The restricting element is a type of valve that can either be a globe valve, butterfly valve, poppet valve, or any other form of valve, which is capable of operating as a variable restriction to the flow.
  • The loading element applies the needed force to the restricting element. It can be any number of things such as a weight, a spring, a piston actuator, or more commonly the diaphragm actuator in combination with a spring.
  • The measuring element determines when the inlet flow is equal to the outlet flow. The diaphragm is often used as a measuring element because it can also serve as a combine element.

In the pictured single-stage regulator, a force balance is used on the diaphragm to control a poppet valve in order to regulate pressure. With no inlet pressure, the spring above the diaphragm pushes it down on the poppet valve, holding it open. Once inlet pressure is introduced, the open poppet allows flow to the diaphragm and pressure in the upper chamber increases until the diaphragm is pushed upward against the spring, causing the poppet to reduce flow, finally stopping further increase of pressure. By adjusting the top screw, the downward pressure on the diaphragm can be increased, requiring more pressure in the upper chamber to maintain equilibrium. In this way, the outlet pressure of the regulator is controlled.

2.5.1 Single Stage Regulator

As the spindle pertaining to the cylinder is gradually opened,  high pressure gas from the cylinder travels into the regulator via an inlet valve, and enters the body of regulator that is inhibited by the needle valve. With the increase of  pressure within the regulator, both the valve as well as the diaphragm proceed to close the valve and stop any gas from entering the regulator. The opening  is fixed with a pressure gauge that indicates the working pressure on the blowpipe. While the gas is being drawn from the  channel, the pressure within the regulator body falls. The diaphragm is pressed back by the spring and the valve opens, allowing additional gas in from the cylinder [9].  Thus, the  pressure within the body  depends on the pressure of springs, which can be attuned by means of a regulator knob. Untitled:Users:macbook:Desktop:300px-Single-stage-regulator.svg.png Figure 2.7: One stage Regulator

2.5.2 Double Stage Regulator

A DSR contains two regulators that work to reducing the pressure gradually in a two-stage process [10]. The present is the first stage, in which the cylinder pressure is reduced to a transitional stage; gas at that pressure passes into the second stage. The gas now emerges at a pressure (working pressure) set by the pressure adjusting control knob attached to the diaphragm. Two stage regulators have two safety valves, so that if there is any excess pressure there will be no explosion. A major objection to the single stage regulator is the need for frequent torch adjustment. If the cylinder pressure falls the regulator pressure likewise drops, thereby necessitating torch adjustment. In the two stage regulator, there is automatic compensation for any drop in the cylinder pressure. Single stage regulator may be used with pipelines and cylinders. Two stage regulators are used with cylinder and manifolds. Untitled:Users:macbook:Desktop:300px-Two-stage-regulator.svg.png Figure 2.8: Two Stage Regulator

2.6 Pressure Sensors

A pressure sensor is a device that measures pressure, characteristically of either liquid or gas. Pressure (usually expressed as force per unit area) is generally defined as the amount of force necessary to prevent the expansion of a liquid.  Pressure sensor act as transducers and generate signals as a result of the enforced pressure. Pressure sensors are widely used in everyday applications for monitoring and controlling purposes. These sensors could also be used to measure other parameters such as altitude, water level and speed. Pressure sensors are also referred to as pressure transmitters, transducers, senders, and pressure indicators. There could be a drastic variation in the design, technology and performance of pressure sensors. A moderate assessment is that there might be over 50 technologies, as well as 300 companies that specialize in manufacturing pressure sensors worldwide. Certain pressure sensors are designed to measure the changes of pressure in extremely high speeds.   Such pressure sensors find wide use in various applications such as the measurement of combustion pressure within a gas turbine. These sensors are generally produced from piezoelectric constituents such as quartz. Certain pressure sensors, similar to those integrated into traffic cameras, operate in a binary mode, which means that when pressure is supplied to a pressure sensor, the sensor in turn, work to either complete or discontinue a circuit. These sets of sensors are also identified as a pressure switch.

2.7 Types of Pressure Measurement

Pressure sensors can be referred to in terms range of temperature operation, range of pressure measurement, and most significantly the type of pressure they measure. Pressure sensors are variously named according to their function.  However, the same technology may be used under different names [11].

2.7.1 Absolute pressure sensor

This sensor measures the pressure in relation to perfect vacuum.

2.7.2 Gauge pressure sensor

This sensor determines the pressure in relation to atmospheric pressure. One example of this apparatus is a tire pressure gauge, which when indicating zero, the pressure it is measuring is identical to the ambient pressure.

2.7.3 Vacuum pressure sensor

A vacuum pressure sensor refers to a sensor, which measures pressures below atmospheric pressure, thereby depicting the difference between low pressure and atmospheric pressure.  However, it may also be used to portray a sensor that measures low pressure compared to a perfect vacuum (i.e. absolute pressure).

2.7.4 Differential pressure sensor

Differential pressure sensor is a sensor that determines the difference between two pressures, of which; one is linked to every side of the sensor.  These sensors are required to measure numerous properties, such as a drop in pressure across either air or oil filters, level of a fluid (by evaluating the pressure over and beneath the liquid) or flow rates (by measuring the alteration in pressure across a restraint). The majority of pressure sensors are classified as differential pressure sensors; A gauge pressure sensor is simply a differential pressure sensor where one surface is open to the ambient atmosphere.

2.7.5 Sealed pressure sensor

An SPS is similar to a gauge pressure sensor excluding the fact that it measures the relative pressure in relation to a fixed pressure, instead of the ambient atmospheric pressure (which fluctuates according to the position and the climate).

2.8 History Of Pneumatics

The first example of a pneumatics application can be tracked to as far back as the first century, when the ancient mathematician of Greek origin, best known as the Hero of Alexandria, wrote about his ingenious inventions that were run by either wind or steam. However, none of his considerations revealed intentions of operating pneumatic devices for transporting objects. 
On the other hand, German physicist Otto von Guericke (1602-1686) moved a little further by inventing the vacuum pump, a device capable of drawing either air or gas from any vessel it is attached to. He illustrated that vacuum pump air pressure could be utilized in order to separate pairs of copper enclosures called hemispheres.

2.8.1 Capsule Transportation

The capsule was first invented in 1886 and allowed people to transport items by placing them in a container. People in Victorian England were the first known to use capsule pipelines to transmit telegrams from one telegraph station to another.

2.8.2 Postal Systems

Scottish engineer William Murdoch (1754 to 1839) was the first to apply pneumatics to postal services, but there is little evidence that he went further than suggesting the transmission of letters and packages through pneumatic tubes. American merchant John Wanamaker (1838 to 1922) installed a pneumatic system in the United States Post Office when he was postmaster general and in department stores to transport money from one section to the other.

2.8.3 Public Transportation

Pneumatics was also applied to public transportation. A notable example is the efforts of American inventor Alfred Beach (1826 to 1896). In 1867, Beach demonstrated a pipe able to transport a handful of passengers, giving birth to the pneumatic subway line. However, the line only lasted for a few months, terminated after Beach was unable to gain permission to extend the distance of the subway.

2.9 Vacuum Pumps

A vacuum pump is a device that removes gas molecules from a sealed volume in order to leave behind a partial vacuum. The first vacuum pump was invented in 1650 by Otto von Guericke, and was preceded by the suction pump, which dates to antiquity. Positive displacement pumps are the most effective for low vacuums. Momentum transfer pumps in conjunction with one or two positive displacement pumps are the most common configuration used to achieve high vacuums. In this configuration the positive displacement pump serves two purposes. First it obtains a rough vacuum in the vessel being evacuated before the momentum transfer pump can be used to obtain the high vacuum, as momentum transfer pumps cannot start pumping at atmospheric pressures. Second the positive displacement pump backs up the momentum transfer pump by evacuating to low vacuum the accumulation of displaced molecules in the high vacuum pump. Entrapment pumps can be added to reach ultrahigh vacuums, but they require periodic regeneration of the surfaces that trap air molecules or ions. Due to this requirement their available operational time can be unacceptably short in low and high vacuums, thus limiting their use to ultrahigh vacuums. Pumps also differ in details like manufacturing tolerances, sealing material, pressure, flow, admission or no admission of oil vapour, service intervals, reliability, tolerance to dust, tolerance to chemicals, tolerance to liquids and vibration. Vacuum Pumps can be broadly categorized according to three techniques: 2.9.1 Positive displacement Pumps These pumps use a mechanism to repeatedly expand a cavity, allow gases to flow in from the chamber, seal off the cavity, and exhaust it to the atmosphere. 2.9.2 Momentum transfer Pumps MTPs, also called molecular pumps, use high-speed jets of dense fluid or high speed rotating blades to knock gas molecules out of the chamber.

2.9.3 Entrapment pumps

EPs are responsible for capturing gases in a solid or adsorbed state. This includes cryopumps, getters, and ion pumps.

2.10 Comparison of Pneumatics to Hydraulics

Both pneumatics and hydraulics are applications of fluid power. Pneumatics uses an easily compressible gas such as air or a suitable pure gas—while hydraulics uses relatively incompressible liquid media such as oil. Most industrial pneumatic applications use pressures of about 80 to 100 pounds per square inch (550 to 690 kPa). Hydraulics applications commonly use from 1,000 to 5,000 psi (6.9 to 34 MPa), but specialized applications may exceed 10,000 psi (69 MPa).

 Advantages of pneumatics:

  • Simplicity of design and control—Machines are easily designed using standard cylinders and other components, and operate via simple on-off control.
  • Reliability—Pneumatic systems generally have long operating lives and require little maintenance. Because gas is compressible, Equipment is less subject to shock damage. Gas absorbs excessive force, whereas fluid in hydraulics directly transfers force. Compressed gas can be stored, so machines still run for a while if electrical power is lost.
  • Safety—There is a very low chance of fire compared to hydraulic oil. Machines are usually overload safe.

 CHAPTER 3

METHODOLOGY

3.1 Introduction

This chapter explains the proposed design, sizing and dimensioning of parts and load calculations. The following sections discuss in detail the optimization of capacitor size, capacitor allocation and switching of capacitor. The general procedure derived from proposed method is summarized at last. The following flowchart describes the chronological steps followed to achieve the objectives of the project.  First of all, literature review is carried out in order to gain a clearer background with respects to previous research carried out on similar topics.  Following this initial yet crucial step in methodology, a comprehensive concept generation stage is carried out in order to produce viable options for meeting the objectives set forth.  Following this phase was the concept evaluation phase, in which the various pros and cons of each concept are scientifically evaluated in order to produce a successful design. Having set forth an established final design, an extended market research is then carried out in order to integrate various essential items into the design that are necessary for attaining a sustainable and efficient lift mechanism along with selecting suitable material to establish locomotion of the final product. NO NAME:flowchart:Capture.PNG Figure 3.1: Methodology Flowchart

3.2 Concept Generation

3.2.1 Concept 1:

H:\pictures for project\30134.jpg Figure 3.2: First Concept Figure 3.2 illustrates the first designed concept that is based on the standard heavy weight hydraulic lifters currently present in all maintenance shops, the reason why this concept generated great promise was due to the ability of installing a lift mechanism through four independent pillars, allowing for a more promising result.  However, due to the fact that no provisions were made for motion, the above design required an urgent revision.

3.2.2 Concept 2:

H:\pictures for project\45379-1.jpg Figure 3.3: Second Concept Figure 3.3 depicts the second generated concept, which offers an alternative lifting mechanism to the first concept, and offers numerous benefits to the original concept due to its more compact nature.  Here, the lifting mechanism is attained by means of compressors that supply compressed air to two individual pillars.  However, a major hindrance in the form of inability to provide a steady safe form of motion led to this concept being dropped.

3.2.3 Concept 3:

H:\pictures for project\original.png Figure 3.4: Third Concept Figure 3.4 illustrates the third and final concept generated in the conceptual design phase.  This was originally the most promising concept due to a superior safety factor, and the ability of providing lift through an actuator placed either at the base, centre point or both.  However, this concept was omitted due to the inability of this design to meet with a vital requirement of the objectives, which is to offer a work area underneath the lifted vehicle.

3.3 PNEUMATIC MOTOR:

The key objective of the design is to lift a body of weight 2000 N.  Therefore in order to figure the type of pneumatic motor that is capable of achieving this out of the various motors available (i.e.Gerotor air motors, milling motors, motor/engine starters, piston motors, turbine motors, and vane motors), it is vital to first determine the required torque to lift a vehicle of the stated weight, which can be calculated as follows, assuming a lifting acceleration of 1 m/s2, a motor radius of 0.3 m and the cylindrical motor to be of 30 kg weight [13]. T= FR sin  T= I  Tnet= 1/2MPRP2P   Which would imply that the net torque for the motor would be: Tnet= (Fmotor– T1)Rd= MdRd2 Fmotor=  Md + T1 Which implies that: [tex]/tau_{motor} = F_{motor} R _motor weight = 1895Nm Therefore, the most suitable pneumatic motor for the design could be vane motor, a result of which vane motor model 68-S169 K was chosen for the design due to it having the ideal required properties that are listed in this table as follows: Untitled:Users:macbook:Desktop:Screen shot 2013-01-28 at 12.48.23 PM.png Untitled:Users:macbook:Desktop:393538_medium.png Figure 3.2: Vane Motor

3.4 LOCOMOTION

  1. Top Mount

Untitled:Users:macbook:Desktop:Screen shot 2012-11-19 at 10.36.10 AM.png

  1. Side Mount

Untitled:Users:macbook:Desktop:Screen shot 2012-11-19 at 10.36.32 AM.png Figure 3.3 Top and side Mounts of Castor Wheels The ability of the pneumatic lifter to move the vehicle into any location is made possible by the simple installation of the above heavy duty castors that have multiple functionality, with the wheels made out of cast nylon.  Hence allowing it the strength to handle excessive loads while allowing any personnel to move a two ton mass by the application of very little amount of force.  The following diagram indicates the rotation capabilities of castors installed in respective positions along with the load capacity for each castor wheel.

CHAPTER 4

RESULTS AND DISCUSSION

4.1 Introduction

This chapter aims at offering a comprehensive oversight of the finalized design with respect to the conclusive dimensions of the various components, along with the results attained from the stress analysis test, which would attain whether or not the final product would be capable of withstanding the weight set forth of 2 tons.  Further discussions with regards to the results attained are also provided.

4.2 Design Parameters

Figure 4.1 illustrates the finalized design, which after the comprehensive concept evaluation phase, was largely influenced by the first concept, however various altercations were made so as to allow horizontal motion to the lifted vehicle. It’s designed to lift the vehicle to a distance of 7 feet, thereby complying with the requirements of the objectives, and allowing for sufficient room for a mechanic to perform maintenance work on the undercarriage.  Figure 4.2 on the other hand, depicts the stress strain analysis carried out on the final design where as figures (4.4- 4.8), offer detailed depiction of the numerous component parts that formulate the design. The reason why this concept generated great promise was due to the ability of installing a lift mechanism through four independent pillars, allowing for a more promising result. This designed concept that is based on the standard heavy weight hydraulic lifters currently present in all maintenance shops. Untitled:Users:macbook:Desktop:omar's fyp2 presentation:Screen shot 2013-01-03 at 2.00.32 AM.png Figure 4.1:  Final Design/Users/tarig/Desktop/Picture1.png   Figure 4.2 : Stress Strain Analysis 4.3 Component Parts: Untitled:Users:macbook:Desktop:Screen shot 2013-01-27 at 6.13.00 PM.png Figure 4.3: Pole Design Untitled:Users:macbook:Desktop:Screen shot 2013-01-27 at 6.10.52 PM.png Figure 4.4:  Upper Support second support (upper part).JPG Figure 4.5: Upper Support (Secondary Part) support for the car .JPG Figure 4.6: support for the car (part 1) support for the car2.JPG Figure 4.7: support for the car (part 2) wheel.JPG Figure 4.8: Locomotion Component   4.4 Final Design Parameters: Table 4.1: Specifications of Pneumatic Lifter

SPECIFICATIONS PNEUMATIC LIFTER
RETRACTED HEIGHT OF BASE 0.115 m
ELEVATED HEIGHT 2.133 m
LENGTH 4 m
WIDTH 1.1 m
POWER SOURCE Air Compressor
MAXIMUM LIFT LOAD Approx. 3,263 kg
OVERALL PROJECTED WEIGHT 500 kg
WHEEL TURNING CIRCLE 3600
REQUIRED AIR PRESSURE 100-150 psi
DIRECTION OF LOAD Front or Rear entry
ONBOARD ELECTRONICS None

  Table 4.1 highlights the general parameters of the pneumatic lifter, whereby it is illustrated that the source of power for the design is derived via an air compressor that provides an air pressure ranging from 100-150 psi.  It also illustrates that the turning circle of cast wheels installed in the design are capable of rotating in 3600      Table 4.2: Specifications of Vane Motors Untitled:Users:macbook:Desktop:Screen shot 2013-01-28 at 12.48.23 PM.png Table 4.2 gives a comprehensive depiction of the vane motor that is selected for the design.  These paramters were attained from current industry standard  pneumatic motors that are available in the present market.  With the ability of providing torque above 1800 N-m, and with an air fitting of 1”, this specific vane motor is capaable of providing the required force for lift, by usingstandard pressure vessels.   Table 4.3: Specification of castors Untitled:Users:macbook:Desktop:Screen shot 2013-01-28 at 12.49.14 PM.png

4.5 Calculation of Time and Velocity:

4.5.1 Time Required to Lift the Vehicle:

From the selected vane motors specifications, it is clear that it would be able of providing a uniform acceleration of 0.025 m/s2.  As the distance required for the vehicle to travel is 7 feet (approx. 2.1336 meters), the time required to lift the vehicle could be calculated from the following equation:   S= ut + 1/2(at2) 2.1336= ½(0.25)(t2) Therefore, T= 13 seconds

4.5.2 Time required for Horizontal Motion:

In order to calculate the time required for horizontal motion, a slight altercation is made to the above equation, in the form of distance travelled which is 4 meters. S= ut + ½(at2) 4= ½(0.025)(t2) Hence, T = 18 seconds

4.5.3 Velocity Provided By Vane Motor:

The velocity with which the vehicle is lifted is determined by utilizing essential data gained from the above equation, where the time required to lift the vehicle is ascertained to be 13 seconds.  Therefore, the lift velocity is as follows: V = u + at V = 0.025(13) Hence, the lift velocity is given as: V= 0.325 m/s   4.6 DISCUSSION:   The above figures illustrate in detail the finalized design, which is largely bound on the first original concept that has been heavily modified in order to provide both vertical as well as horizontal motion to the lifted vehicle.  A comprehensive market research that was carried out revealed that the required lift for safely lifting the required weight set forth of 2 tons, could be adequately adhered to by the use of two sets of vane motors in each pillar, that would be capable of providing up-to 2670 N-m of torque. The reason why the original design was heavily modified in order to formulate the final product is that, expansive research revealed that for the sake of safety when it comes to the handling of heavy weight items in the aforementioned weight, a predetermined path of motion was essential so as to formulate a safe work area surrounding the lifted vehicle, and offering practicality by allowing motion through different areas so as to ease the process of most essential requirements of lifting a vehicle such as removing the engine, gearbox, and the carrying out of undercarriage maintenance in specified areas. In order to completely adhere to the requirements of the design objectives, measures for absolute mobility were integrated into the design by the installation of heavy duty industrial castors made out of cast nylon, each capable of withstanding a weight exceeding 1 ton, while stress strain analysis indicated that the proposed design should be capable of withstanding a force of 32000 N/m2 which equals approximately 3.263 tons, thereby surpassing the required value. From the calculations carried out based on information attained from the technical specifications of materials selected, it was then found that the time required to lift a vehicle weighing 2 tons, a total time of 13 seconds, at a uniform velocity of 0.326 m/s.

CHAPTER 5

CONCLUSION AND RECOMMENDATION

5.1 Conclusion

After adhering to the strict design discipline set forth in the methodology phase of the project, the objectives of this project were met in a truly satisfactory manner, thereby designing one of the world’s first pneumatic lifter capable of safely and efficiently carrying a car weighing up-to 2 tons, in order to carry out undercarriage maintenance. In current industry, such heavy weight duty is reserved for hydraulics rather than pneumatics, due to the predictable and un-compressible property of liquids.  The various dangers associated with the utilization of compressed air for such applications is that compressed air could be very unpredictable, and if a direct feeding mechanism was considered for the design, additional impracticalities would have been faced in the form of excessive heat generated in harnessing such vast amounts of pressure.  However, such hindrances were avoided by the integration of pneumatic motors into the design, whereby even at low speeds, sufficient torque could be generated to provide lift for the vehicle. In the concept generation phase of the project, various pneumatic motors were considered for the lifting mechanism (such as gerotor air motors, milling motors, motor/engine starters, piston motors, turbine motors, and vane motors), out of which, the vane motor was selected due to it being able to produce a required force of 2670 N-m.  Thus four vane motors installed into the design would be able to safely lift any vehicle in excess of 2 tons.  This coupled with the fact, that it’s inlet air fitting is 1 inch, and requires an air pressure ranging from 100-150 psi in order to produce the stated torque.  This means that this design would bring forth radical practicality, by its ability to be directly integrated into any current work shop that utilizes standard pressure vessels for the use of bolt removal in tires. In terms of mobility, the finalized design is capable of providing two forms of motion.  The first form allows for enhanced safety, by adhering to the requirement of mobility through the use of a predetermined path.  Here, the vane motors are capable of lifting a vehicle in a time span of only 13 seconds, with a constant velocity of 0.325 m/s.  However, in the case of boundary-less motion, two sets of specialized castors made of cast nylon were integrated into the final design due to its ability to rotate in 3600, while being able to support a weight of 1 ton each. Arguably the biggest innovation in this design is its breakthrough application of vane motors in order to vent the various dangers associated with handling high pressure gases, whereby only small pressure is required to generate the required amount of torque necessary to lift the vehicle.  Thereby, getting rid of the issue of the un-predictable nature of compressed gases. Thus, the wide spread use of this design in the field of car maintenance could possibly revolutionize this industry, by allowing for a work environment that is much cleaner as air could simply be vented out of the machine where as hydraulic require constant rigorous maintenance, while evacuating the hydraulic fluid.

5.2 Recommendations

Due to the uniqueness of this design, and it being one of the first attempts at providing a viable alternative to current hydraulic heavy weight lifters, there are a variety of recommendations for future development of the current pneumatic lifter.  The first is to providing a more efficient design by means of installing a single feed in mechanism for torque, which would allow for a design that is more compact, and hence, cheaper to operate. Furthermore, the application of stronger, more advanced materials, along with a more developed feed in mechanism for torque, could offer numerous benefits by providing a lifting capability to cars weighing in excess of 5 tons. Enhanced safety standards and controllability of the heavy weight lifter could also be enhanced by the integration of electronic sensors and components into the design, which would provide an automated operation. The current design has been developed according the realization of the latest technical expertise available with the regards to pneumatic devices.  However, it is expected that the current design would be capable of coping with future development in this field, with the advent of more advanced pneumatic motors, whereby a simple exchange of the motor could offer superior performance.  It is therefore most recommended that any addition to the current design should be done, with the perspective of future performance of design.

REFERENCES

[1] Tian Hongyu & Zhang Ziyi, Design and simulation Based on Pro/E for a Hydraulic Lift Platform in Scissors type, International Workshop on Automobile, Power and Energy, 2011. [2] A.Mehmood, S. Laghrouche & M.El Bagdouri, Modellig identification and simulation of pneumatic actuator for VGT system, Laboratoire S.E.T., Universite de Technologie de Belfort-Montbeliard, Belfort, France. [3] Sebastian Butefish, Volker Seidmann & Stephanus Buttegnbach, Novel micro-pneumatic actuator for MEMS, Institute for Microtechnology, Technical University of Braunschweig, Alte Salzdahlumer Str. 203, 38124 Braunschweig, Germany, 2002. [4] Ming-Chang Shih & Shy-l Tseng, Identification and position control of a servo pneumatic cylinder, Control Engineering Practice, 1995. [5]Air motors. Retrieved 10 October 2012, from http://www.hydraulicspneumatics. com/200/TechZone/FluidPowerAcces/Article/True/6422/TechZone-FluidPowerAcces [6] Technology zone-air motor. Retrieved 23 October 2012, from http://www. hydraulicspneumatics.com/200/TechZone/FluidPowerAcces/Article/True/6422/TechZone-FluidPowerAcces [7] H.M Mahgoub & I.A. Craighead, Development of a microprocessor based control system for a pneumatic rotary actuator, Mechatronics, Volume 5, Issue 5, August 1995. [8] V. Tesar, Extremely simple pressure regulator-computation studies, Chemical Engineering Journal, Volume 155, December 2009. [9] One Stage Regulators. Retrieved 24October 2012, from http://www.scott- marrin .com/one_stage_regulators.htm [10] Two Stage Regulators. Retrieved 24 October 2012, from http://www.scottma -rrin.com/two_stage_regulators.htm [11] Jin Li, Hao Liu, Yuzxiu Wang, Lingling Shi & Fengxia he, Development of a low cost portable pressure measurement system using for garment design, Measurement, Volume 45,  October 2012. [12] M. Zagnoni, A. Golfarelli, S. Callegari, A. Tamelli & V. Bonora, A non-invasive capacitive sensor strip for aerodynamic pressure measurement, Sensors and Actuator A: Physical, Volumes 123-124, September 2005. [13] J. Naranjo, E. Kussul & G. Ascanio, A new pneumatic vanes motor, Mechatronics, Volume 20, Issue 3, April 2010.

APPENDIX A:

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APPENDIX B:

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APPENDIX C:

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