Design
Report
Upgrade of six dated Powerpacks
Research to the design of an oil cooling system, waterproof housing and to the
reduction of the noise level.
Author:
Name: Fabian Putters Studentnr: 2017093
School: Avans University of Applied Science
Company:
Name: ALE Heavylift B.V.
Place: Breda
Date: 8-Jun-11
General Data
Project: Upgrade of six dated Powerpacks
Company data:
ALE Heavylift B.V. Konijnenberg 68 4825BD Breda + 31 (0) 76 543 14 14
Company tutor:
Kees Claasen
K.Claasen@ale-heavylift.com +31 (0) 76 571 52 40
Educational institution: Avans University of Applied Science Academic for Technology and Management Department of Mechanical Engineering Lovensdijkstraat 61-63 4818AJ Breda Reception +31 (0) 76 525 05 00 Post address: Avans Hogeschool Postbox 90.116 4800 RA Breda
School tutor: Michael Meijers
Maha.meijers@avans.nl +31 (0) 76 525 05 00
Student:
Fabian Putters
Meeuwberg 27 4708NH Roosendaal fabianputters@gmail.com +31 (0) 165 391196 +31 (0) 6 54307855 Student number: 2017093
Foreword
This design report is the result of a half year during graduation project in cooperation with the company ALE Heavylift B.V. located in Breda. This project was done by a student Mechanical Engineering at the Avans University of applied science which is also located in Breda.
The goal of this report is to inform the reader about ALE Heavylift B.V. and the project which has been done during the graduation period of the student. The subject of the graduation project is the upgrade of six dated hydraulic powerpacks. Readers who are mainly interested in the final design will find this in chapter 5.
The student would like to take this opportunity to thank the people who shared their professional experience during the length of this graduation project. From ALE Heavylift these are: Kees Claasen, Sander Bogemann, Rob Metselaar and Robert van den Kieboom. From Avans this is Michael Meijers as tutor during this graduation project.
Breda, June 8, 2011 Fabian Putters
Table of Contents
General Data ... i
Foreword ... ii
Summary ... iv
1.
Introduction ... 1
2.
Oil cooling ... 2
2.1.
General... 2
2.2.
List of requirements ... 3
2.3.
Method of cooling ... 4
2.4.
Possible oil cooling concepts ... 5
2.5.
Kesselring method ... 7
2.6.
Possible oil cooling units ... 9
2.6.1. Oil cooler type: OK-ELD ... 9
2.6.2. Oil cooler type: OK-P ... 9
2.6.3. Oil cooler type: OK-ELH ... 10
2.6.4. Chosen cooling unit ... 10
2.7.
Detailed elaboration of the chosen concept ... 12
2.7.1. Wabco Air Dryers ... 15
3.
Noise reduction ... 16
3.1.
General... 16
3.2.
List of requirements ... 17
3.3.
Sound reduction methods ... 18
3.3.1. Insulation plates ... 18
3.3.2. Muffler inside the housing ... 19
3.3.3. Sound reduction accessories ... 21
3.4.
Results ... 22
4.
Housing ... 23
4.1.
General... 23
4.2.
List of requirements ... 24
4.3.
Design of the upgraded powerpack ... 25
4.3.1. Skid frame... 26
4.3.2. Hydraulic oil tank ... 27
4.3.3. Engine, Hydraulic pump and Manifolds ... 27
4.3.4. Frame and Lifting eyes ... 28
4.3.5. Ventilation roster and Oil cooler ... 29
4.3.6. Roof plates... 29
4.3.7. Doors and Panels ... 30
5.
Final Design ... 32
5.1.
General Assembly... 32
5.2.
Implementation of Design... 35
6.
Conclusion ... 36
7.
Recommendations ... 37
Bibliography ... 38
Glossary ... 39
List of Symbols ... 40
Summary
ALE Heavylift B.V. is a globally operating company with experience in the transport of cargo with immense dimensions and loads. One of the machines ALE uses to be able to transport these loads are powerpacks. These machines are able to pressurize hydraulic oil to around 400bar for operations such as: jacking, skidding and lifting. ALE has a dozen of these powerpacks which operate in all kinds of different environments. A number of these powerpacks are dated and need an upgrade to ensure the lengthening of the lifetime. This upgrade will also create better work environments for the operators of these powerpacks.
Together with ALE a graduation project was set up to make a plan for the upgrade of these powerpacks. After the preliminary research, the decision, together with the company tutor was made to make a report for the upgrade of six powerpacks (1050-11/12/16/17/21 & 23). At the start of the project, three issues with the powerpacks where made clear which needed to be solved. The solution to these issues should also be the result of this project. One of these problems occurs when operating in hot weather conditions. Since the powerpacks are not equipped with oil coolers a lot of problems occur due to the heated oil running through the system. Another issue with the current housings of the powerpacks is that they are not rain water proof. When the water drips inside the housing it gets mixed with any leaked oil. This makes it look like if the entire leak tank is filled with oil, while most of this is water. Another issue is the high noise level produced by the engine and its components. With the knowledge of the issues explained above the following list of problems needs to be solved or improved:
- The implementation of hydraulic oil coolers to all six powerpacks. - The design of a complete new housing for the six regarding powerpacks. - Reduce the noise level produced by the powerpack.
To keep the heated hydraulic oil at a considerable temperature, an oil cooler has been chosen using the Kesselring method. The chosen oil cooler has to be implemented in the return line of the hydraulic system just in front of the return line filter, this is also chosen using the Kesselring method. During meetings with involved mechanics and operators an additional issue with the powerpacks came to light. Due to the hydraulic pump, oil gets sucked out of the tank. Ambient air takes in the created space in the tank, this air is not filtered in any way. This means that the moist inside the air finds its way to the hydraulic oil. Water in the hydraulic system can cause cavitation to the hydraulic pump and damage the entire system. To solve this, Wabco air dryers have been mounted to dry the air before it enters the tank.
For the lowering of the noise level a couple of additions have been made compared to the current powerpack. For example the muffler of the exhaust is replaced by a new muffler with an integrated spark arrestor. The muffler is now mounted inside the housing instead of on top of the powerpack. Also insulation plates have been chosen to cover the inside of the newly designed housing. Door rubber is chosen to cover the jambs to prevent vibrations between the door and the jamb. Also a new ventilation roster has been selected which reduces the noise slightly because it is filled with rock wool which has a noise damping property.
The new design for the housing has a complete new layout compared to the current powerpacks. The hydraulic oil tank is lowered to a position between the skid frame. This creates a lot of space above the tank, this space is exactly enough to hold the control panel of the powerpack. With the relocation of the control panel a lot of space is created in the ‘engine room’ which was necessary for the integration of the muffler. Also two leak tanks have been designed to catch any leaking oil. These are located in the ‘engine room’ and below the manifolds for the quick release couplings. The oil cooler is mounted between the ‘engine room’ and the top of the hydraulic tank. Also a frame for the insulated ventilation roster had to be designed because there was only a limited amount of space available behind the radiator fan. The new roof plates run skewed which ensures the quick process of rain water, this also ensures that the new housing is rain water proof.
The skid frames are not going to be adjusted, a housing is designed which fits all current skid frames. Since the basic metal work can be done in the ALE workshop, the choice has been made to outsource the special parts of the housing this includes the: doors, panels, roof plates, hydraulic oil tank and all other special parts. See appendix 14. The costs for the upgrade of one powerpack will cost around €8.985,88. This automatically means that the upgrade for all six powerpacks will cost €53.915,3. With this design the powerpack will be splash water proof and ensures a permissible oil temperature. After the implementation of this design the noise level is 80 dB(A) which is a reduction of 4 dB(A). It is recommendable to do this upgrade since it will significantly extend the lifetime of the powerpacks.
1. Introduction
ALE is a globally operating company with experience in heavy and specialist transport. ALE has a global network of operating centres and a large fleet of heavy cranes, specialist transport and installation equipment. ALE combines exceptional project management with engineering intelligence to offer worldwide transportation and lifting services to all industry sectors. ALE Heavylift B.V. is the Dutch division of ALE and is stationed in Breda. The research during this project is done within this division. More company information is available in appendix 1: PMD.
One of the machines ALE use for their services are powerpacks these deliver pressurized hydraulic oil to a system. These powerpacks are bought from a company who is specialized in the fabrication of hydraulic equipment. ALE uses powerpacks for operations such as: jacking, skidding, lifting, weighing, SPMTs etc. There are different types of powerpacks, the SPMT powerpacks can only be used to power the (Self Propelled Modular Transporters) these are not relevant for this project. The other powerpacks are either diesel driven or electrical driven these have the same function and working pressure. However the difference between them is power [kW], capacity [L/min] and the content of the hydraulic oil tank [L].
A number of these powerpacks are fabricated about 20 to 30 years ago. This makes them dated and sensitive for failure. Most problems occur when operating in countries which have an extreme hot or cold climate. Most of these powerpacks are not equipped with heat exchangers/coolers to regulate the hydraulic oil temperature. This can result in oil breakdown, hot contact surfaces etc. Problems also occur when it is raining because the current housing of these powerpacks is not rainwater proof. This also means a higher chance for failure, which cannot happen when the powerpacks are in the middle of an operation. Because the powerpacks are fabricated a long time ago, the noise levels these machines produce are much higher compared to the four recently bought powerpacks. This creates annoying workplaces for the operators of these units.
The goal of this project is to find solutions for the issues of the regarding powerpacks which are listed below. - The implementation of hydraulic oil coolers on all powerpacks,
- Design a new splash water-proof housing for the regarding powerpacks, - Reduce the noise level of the powerpack,
Preliminary research showed that the scope of this project is about six older types of powerpacks see appendix 2: Preliminary research. The model numbers of these units are 1050-11 / 12 / 16 / 17 / 21 and 23. The inventory which is made at the start of this project showed that the six powerpacks are not equipped with oil coolers. The housing and noise production issues are also present at all of the six powerpacks. Data sheets of the six powerpacks listed above are made available in appendix 16.
ALE Heavylift B.V. is curious to the results of this project. Because an upgrade for the issues listed above is important for the lifetime of the powerpacks. The upgrade should also result in better handling situations for the people who operate these machines. The three issues listed above are known problems for the six regarding powerpacks. During the project more unknown issues about these powerpacks could arise, this is not known at this moment.
The boundary which is given by ALE Heavylift B.V. is to find a solution for the issues listed above. These solutions should be implemented on the six regarding powerpacks which are also listed above.
The three above standing main goals which needed to be solved are very different from each other. Since they are so different, the decision has been made to create three different chapters. These three chapters have the same build up. They include a general description of the problem, a separate list of requirements, the possible solutions, the chosen solution and the eventual results of the regarding chapter. This sequence is used to find the solution for the three above standing main subjects.
The structure of this design report is as follows. Chapter 2: Oil cooling describes the design made for the oil cooling system. Chapter 3: Noise reduction describes the design process for the sound reduction of the powerpacks. Chapter 4 shows the design of the housing for the six powerpacks. The content of chapter 2, 3 and 4 are build the same, and is described in the paragraph above. Chapter 5 sums up the result of the chosen design. It also contains the eventual costs needed for the upgrade. Finally, the conclusion and recommendations of this project are given in chapter 6 and 7. The literature which is used during this project is listed in the chapter bibliography. The special terminology used in this report is shown in the chapter glossary. The symbols used in this report are explained in the chapter list of symbols. These three chapters are located at the end of this report. The appendices are not listed in this report due to the large amount of them. These appendices are presented in the attached binder.
2. Oil cooling
This chapter describes the reasons and possibilities of oil cooling in the existing design of the regarding powerpacks. It also gives the explanation and results of the calculations and the final result of this research. The preliminary research showed, that all six regarding powerpacks have to be equipped with oil coolers. This chapter is about the implementation of oil coolers in the six regarding powerpacks (1050 – 11 / 12 / 16 / 17 / 21 & 23).
2.1. General
This section describes how heat is built up in a hydraulic system and what the possible consequences of these are. This chapter also includes the factors which are important to think about when choosing an oil cooling system. Heat is generated in a hydraulic system whenever oil flows from a higher to a lower pressure without doing
mechanical work. Pressure losses may occur when oil flows trough inadequately sized valves or pipes, kinked hoses or sharp bends in hoses and tubes. Also high ambient temperatures collaborate with high temperatures in a hydraulic system.
What are the risks of overheating the hydraulic oil?
- The lifetime of the entire hydraulic system will be smaller, for example components such as: hoses, pumps, valves etc.
- Seals may wear out more quickly, this will result in leakages.
- The overall temperature of the system increases so there is a possibility that workers get injured due to hot contact surfaces.
- The hydraulic oil has a maximum temperature of 60°C. Higher temperatures will result in damage to the chemical composition of the oil, and this will result in breakdown and oxidation of the oil, creating varnish. For the dimensioning and the right selection of the oil cooler, a number of factors are important. These factors are listed below.
- An accurate description and function of the powerpack needs to be available. - The hydraulic scheme of the powerpack needs to be available and described. - The number of cycles of the system needs to be determined.
- Characteristics of the oil need to be available.
- Temperature of the oil needs to be known, in and outlet temperature needs to be determined. - The type and properties of pump are also necessary.
- Dimensions of hydraulic tubes and pipes which are used in the system need to be determined. - The type of cooling media which needs to be used.
The hydraulic schemes of all six powerpacks are the same, so only one diagram is made visible in appendix 3: Hydraulic scheme of the powerpacks. This scheme shows that one hydraulic pump delivers 4 oil flows to 4 separated groups. The function of these groups is to support a possible load on 4 separate points, this way the load is stable. The pump which is driven by a diesel engine gets its oil from the tank which first passes a suction filter before getting to the pump. The pressurized oil passes another high pressure filter in its way to the manual operated 5/3 valve. This valve passes the oil through to the actuators or other possible applications. The hydraulic system is secured by four adjustable safety valves which can be set to a maximum pressure of 400 bars. The hydraulic schemes of the
powerpacks are not difficult to describe however it is essential for this project to understand them because during this project adjustments in this scheme can be made.
Preliminary research showed that when an oil cooler has to be installed, the heat dissipation and oil flow are the most important factors. The manufacturer of the old powerpacks stated in their reports that when an oil cooler is chosen the heat dissipation should be 30 kW at a maximum oil flow of 140 l/min.
Because recently 4 new powerpacks were bought, these can be used as reference for this project. The available documentation was reviewed and used to find the company who provided the oil cooler. At their website all kinds of cooler types were listed, some of these types were not applicable for this project due to the large dimensions. The components which are used in the new powerpacks are listed, and there has been a research to use them in this project. Knowing this, several calculations can be made to select the right oil cooler.
2.2. List of requirements
This section describes the requirements which are relevant for the oil cooling of the powerpacks during this project. The external requirements are delivered by the company ALE Heavylift B.V. These requirements, which are listed below, are relevant for this project however these are not the only requirements for the powerpacks. The demands which are given below are mainly focused on the oil cooling of the powerpacks, since this is the scope of this chapter.
Functional list of requirements
The content of this list are the demands which are ordered and separated in groups. These groups describe the external, fixed and variable requirements of this project. Intern requirements can be added during the design process. External requirements
These requirements are formulated by the company and the possible involved classification bureaus. - The following powerpacks are the main focus for this project: 1050-11/12/16/17/21 and 23. These
powerpack types were chosen and selected in cooperation with the company tutor.
- The 6 powerpacks regarding this project need to be installed with oil coolers. Due to the warm weather in some countries the hydraulic oil in these powerpacks rises above limits, the coolers need to be mounted to make sure that the temperature of the hydraulic oil is kept within its boundaries.
- The hydraulic schemes should be drawn using AutoCAD since this is the main drawing program used within the company ALE.
- The primary function of the powerpacks is the delivery of pressurized hydraulic oil to a system. Fixed requirements
These are the requirements which every possible design must meet.
- The temperature of hydraulic oil should not rise above 60°C because this is the maximum limit and should also be the limit during this project.
- To get a CE-marking, the regarding demands which are noted in the machine safety standard need to be satisfied.
- The working pressure and flow remains unchanged since this is not the scope of work for this project. - Lifetime of the six regarding powerpacks should be higher after this upgrade.
Variable requirements
These are the requirements which every design needs to meet partially. These demands are the benchmarks and used to choose the best design.
- The chosen oil cooler should fit within the existing hydraulic system of the powerpack. Without changing too much piping in the current hydraulic system.
- The costs of the total installation should be as low as possible.
- The dimensions of the oil cooling system should fit within the existing housing of the powerpack. Since there will be almost no space available within the powerpack, the cooling system should be as compact as possible.
- For the mobility, the weight of the components should be as low as possible, since this influences the weight of the final design, which should be as low as possible.
- The energy costs of the cooling system should be as low as possible since this eventually costs fuel and money.
- The lifetime of the chosen components should be as high as possible to extend the lifetime of the powerpack.
- The method of cooling should be possible in all environments since this is a mobile machine.
Fabrication list of requirements
This list contains the demands which are relevant for the fabrication of the design. - The price of the total oil cooling system should be as low as possible. - The installation time and costs should be as low as possible.
- The amount of components for the design should be as low as possible - Accessibility of the new components should be easy.
- The design should be made of as many standard components as possible. - Maintenance after installation should be as low as possible.
Environmental list of requirements
This list contains the demands which are relevant for the environment. These demands are set by the government and classifications bureaus every design needs to meet these requirements.
- Leakage of the system has to be as low as possible to prevent fluids to contaminate the environment. - All the materials used during design, fabrication and installation should be environmental friendly. - System should be easy and fast to clean.
- Aim is the complete re-use or recycling of used materials and components.
- Energy consumption of the system should be as low as possible to reduce emissions.
2.3. Method of cooling
The content of this section are the different types of cooling units and cooling systems available. The outcome of the preliminary research showed that there are two types of cooling units available. These are air and fluid cooling, both units has their advantages and disadvantages.
The fluid cooling system has a series of tubes inside a closed cylinder. The hydraulic oil flows through small tubes in the unit, and the fluid receiving the heat typically water flows around the small tubes. Routing of the oil can be done to produce a ‘single pass’ oil enters one end and exits the other end or a ‘double pass’ oil enters one end, makes a u-turn at the other end, and travels back to exit at the same side it entered. Figure 2.3.1 shows the design of a single pass fluid cooler.
The air cooling unit is used for an air-to-oil exchange. The air will be forced through the exchanger with a fan or may flow naturally. If an air cooler is used on a mobile machine, it is a finned tube type. This way the exchanger has the biggest surface, and this means the air is able to cool down the oil more rapidly. Figure 2.3.2 shows the design of a heat exchanger which blows air to cool the oil. The working principle of this design is the same as the fluid cooler only this unit uses air to cool the oil.
Figure 2.3.1: Fluid cooler
The place where the cooler gets implemented in the system also has to be chosen. There are two possibilities, cooling in the return line of the hydraulic system or an independent cooling cycle in the hydraulic system. The last is done in the newer powerpacks. The old powerpacks have quick release couplings present where an oil cooler in the return line of the system can be mounted. Examples of these different cooling systems are shown in figure 2.3.3: Figure (a) shows the oil cooler in the return line of the system and figure (b) shows the heat exchanger in a separate independent cooling system.
The next section describes the different concepts which can be made with the information given in this section. These concepts will be described and explained. Also the advantages and disadvantages of the concepts will be listed.
2.4. Possible oil cooling concepts
This section describes four possible designs for different oil coolers and cooling systems. These have to be implemented in the existing hydraulic system of the powerpacks. These concepts are the result of the previous section. The content of this section are the four concepts with their description, advantages and disadvantages.
Air cooling unit in the return line
This subsection describes the advantages and disadvantages of the concept where the hydraulic oil is cooled by an air cooling unit, which is implemented in the return line.
Advantages
- The total system has a compact design compared to the other concepts. The cooling unit is only fed with electricity and uses forced ambient air to cool. Due to this the total size of the system is small.
- Simple installation due to the small amount of components needed.
- Because of the small and simple design installation and operating costs are low.
- For commissioning only electrical energy is required, since the cooler uses ambient air to cool the system. - Everywhere air is possible to use, and since this is a mobile machine this is an important factor.
- The air cooler unit is easier to clean than the fluid cooled system, because it is easier to disassemble. - This system cools the oil before it enters the tank, this way the hot oil doesn’t heat the oil inside the
reservoir.
- When the hydraulic system is in a slow operating cycle such as the slow lifting of a load. The oil can only be cooled when the 5/3 valve is in the middle position. Because the pump is then connected to the tank this way there will be no pressure, since there is no resistance.
Figure 2.3.3a: oil cooling in the return line Figure 2.3.3b: separate oil cooling system
Disadvantages
- Higher noise level compared to fluid cooled systems, the fan of the cooler is the reason of this noise. - Cooling units are relative large in size, due to the dimensions of the fan.
- The oil cooler is not able to withstand the pressure peaks in the return line. This can be solved by using a pressurized by-pass. This component is able to redirect the oil directly to the tank in case of a pressure peak. An accumulator can also be installed to prevent this, because it is able to level the pressure and flow peaks.
Air cooling unit with a separate oil cooling system
This subsection describes the advantages and disadvantages of the concept where the hydraulic oil is cooled by an air cooling unit, which is implemented in a new separate cycle.
Advantages
- Everywhere air is possible to use, and since this is a mobile machine this is an important factor. - The air cooler unit is easier to clean than the fluid cooled system, because it is easier to disassemble. - The cooling system is not depending on the main pump because the separate system has its own system to
retrieve the oil out of the tank, cool it and return the oil back to the tank.
- No danger of pressure or oil peaks in the system because this system has its own loop in the system. Disadvantages
- Higher noise level compared to fluid cooled systems, the fan of the cooler is the reason of this noise. - To install this system a lot more space is needed. A new oil pump is necessary to pump the oil trough the
cooler. This will take a lot of room within the housing of the powerpack, space which might not be there. - Because a lot of components are needed, this system is quite expensive compared to the cooling in the
return line.
- The installation requires more work, because a new system needs to be implemented in the hydraulic scheme.
Fluid cooling unit in the return line
This subsection describes the ad- and disadvantages of the concept where the hydraulic oil is cooled by a fluid cooling unit, which is implemented in the return line.
Advantages
- The system is air-tight so it works very well in dirty environments. - The cooling unit is relative small in size.
- Water has a higher heat capacity, density and thermal conductivity then air.
- Cools the oil before it enters the tank, this way the hot oil doesn’t heat the oil inside the reservoir.
- When the hydraulic system is in a slow operating cycle such as the slow lifting of a load. The oil can only be cooled when the 5/3 valve is in the middle position. Because the pump is then connected to the tank this way there will be no pressure, since there is no resistance.
- Because the cooling unit is relative simple it is low in costs.
- The fluid cooling unit produces a lower amount of noise compared to the air cooling unit. Because it only uses the flow of a fluid to cool the oil
Disadvantages
- The system needs a cooling fluid to cool. This makes the total system larger since there has to be a tank to store the fluid. Or a constant flow of cooled flow needs to be available, but this is hard to accomplish since it is a mobile machine.
- Possibility of mixing oil and water, this can happen due to a rupture inside the cooling unit.
- Costs of the total system are high. Because a lot more components are necessary compared to air cooling. - The heated cooling fluid also needs to be cooled this is only necessary when a closed cooling circuit is used. - Because of the extra components the total necessary space for this system is higher.
- The oil cooler is not able to withstand the pressure peaks in the return line. This can be solved by using a pressurized by-pass this component is able to redirect the oil directly to the tank in case of a pressure peak. An accumulator can also be installed to prevent this, because it is able to level the pressure peaks.
Fluid cooling unit with a separate oil cooling system
This subsection describes the ad- and disadvantages of the concept where the hydraulic oil is cooled by a fluid cooling unit, which is implemented in a new, separate cycle.
Advantages
- Because the cooling unit is relative simple it is low in costs.
- The system is air-tight this means it works very well in dirty environments. - The cooling unit is relative small in size.
- Water has a higher heat capacity, density and thermal conductivity than air.
- The cooling system is not depending on the main pump because the separate system has its own system to retrieve the oil out of the tank, cool it and return the oil back to the tank.
- The fluid cooling unit produces a lower amount of noise compared to the air cooling unit. Because it only uses the flow of a fluid to cool the oil
Disadvantages
- The system needs a cooling fluid to cool. This makes the total system larger since there has to be a tank to store the fluid. This fluid also needs to be cooled, or streaming water has to be available to cool the oil. - Possibility of mixing oil and water, this can happen due to a rupture in the cooling unit.
- Costs of the total system are high because of the external cycle and the fluid cooling system. A lot of components are necessary to let this system work.
- The heated cooling fluid also needs to be cooled. This is only necessary when a closed cooling circuit is used.
- To install this system a lot of space is needed. An additional oil pump is necessary to pump the oil trough the oil cooler.
2.5. Kesselring method
This section includes the four designs which are compared to each other using the Kesselring method (de Beer, 2006).Eventually one structure remains, which meets the requirements best. The requirements used in this method are divided into a functional, fabrication and environmental list. Section 2.2: List of Requirements describes these demands. Every requirement will be met by the four designs to some degree of satisfaction. The design that meets a requirement best gets a 4 rating, the design who least meets the demands gets a rating 1 and the remaining designs, a rating 2 or 3 depending on the extent to which the requirement is met. These matrices are shown in appendix 4: Kesselring method.
The requirements included in this method are weight against each other. This means that an important requirement gets a higher rating and thus counted more heavily. These factors are implemented in three different assessment matrices which are shown in appendix 4: Kesselring method. These three assessments are the variable, fabrication and environmental requirements.
For example: the comparison of requirement 1 and 2 of the variable matrix.
- The chosen oil cooler should fit within the existing hydraulic system of the powerpack. Without changing too much piping in the current hydraulic system.
- The costs of the total installation should be as low as possible.
Here demand one gets compared with demand two. During this project it is more important that the oil cooler fits within the current design of the powerpack then the costs of the total installation. That’s why requirement one gets a rating 1 over requirement two, which can be seen in the matrix shown in appendix 4: Kesselring method.
Figure 2.5.1 on the next page shows the result of the Kesselring method for the oil cooler system. The colored lines within this figure are the 4 regarding designs. These designs are described in section 2.4: Possible oil cooling concepts. The biggest surface drawn in the diagram is the ideal design. This happens when all requirements are met with the highest factor. This automatically means that the design with the biggest surface is the best design of the four designs.
Design 1 is the system where an air cooler gets implemented in the return line. Design 2 is the system where a separate loop gets implemented with an air cooler. Design 3 is the system where the hydraulic oil gets cooled in the return line by a fluid cooling system. Design 4 has a separated cycle where the oil gets cooled by a fluid cooling system. The biggest surface is the light blue line this is the ideal design when all requirements are met with maximum points.
At 80% idealism, this means a surface of 80% of the ideal design, the search for improvements is usually not profitable. The second biggest surface in figure 2.5.1: Kesselring Method is Design 1. This design is the most simple, with the least amount of components necessary. Design 1 is the air cooler mounted in the return line of the system and has a surface of 85% of the ideal surface.
The chosen design, which is the air cooling system in the return line. The newer powerpack types are equipped with a separate oil cooling system. The main reason that the separate cooling cycle failed during this method is the price, size of total system, installation costs and the amount of components. This method shows that a simpler and cheaper design for an old machine is more profitable.
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2.6. Possible oil cooling units
Due to the preliminary research the new powerpacks have been examined. This research showed the manufacturer of the cooling units which is HYDAC. During this stage of the project three different types of cooling units have been chosen which are listed in the next subsections. These designs are selected using the website of HYDAC because this company is specialized in the cooling of hydraulic oil. After the description of the three chosen units a definite design will be chosen in subsection 2.6.4: Chosen cooling unit. To choose a definite cooling unit out of the three possible designs a comparison between the three will be made. With factors like: price, dimensions, energy consumption etc. a definite choice can be made.
2.6.1. Oil cooler type: OK-ELD
These coolers are designed specifically for mobile hydraulic applications where high performance and efficiency are required and physical size must be minimized to allow easy installation. These coolers use a combination of high performance cooling elements and high capacity, long life DC electric powered fans to give long trouble free
operation in arduous mobile hydraulic applications. The compact design allows the coolers to fit most equipment and provide the highest cooling performance in heat dissipation whilst minimizing space required. Figure 2.6.1 shows the possible designs for this cooling unit.
Advantages of this cooler:
- Environmentally friendly. No exchange between water and oil possible. - For commissioning only electrical energy is required.
- Low operating costs, no additional cooling circuit necessary for the cooling medium. Disadvantages of this cooler:
- Small to medium cooling capacity.
2.6.2. Oil cooler type: OK-P
These high performance coolers with axial fans are suitable for hydraulic cooling applications. This coolers use high efficiency axial fans and strong cooling elements to achieve maximum performance. These units have been designed for standard applications where maximum performance is needed at the best price.
Figure 2.6.1: ELD-Series
Advantages of this cooler:
- Environmentally friendly. No exchange between water and oil possible. - For commissioning only electrical energy is required.
- Low operating costs, no additional cooling circuit necessary for the cooling medium. Disadvantages of this cooler:
- Large dimensions.
- Huge build-in space due to the protruding electric engine. - Heavy weight
2.6.3. Oil cooler type: OK-ELH
These coolers are designed specifically for mobile hydraulic applications where high performance and efficiency are required and physical size is minimized to allow easy installation. These coolers use a combination of high
performance cooling elements and hydraulic motors to give long trouble free operation in arduous mobile hydraulic applications.
Advantages of this cooler:
- Environmentally friendly. No exchange between water and oil possible. - For commissioning only the existing hydraulic power can be used
- Low operating costs, no additional cooling circuit necessary for the cooling medium. Disadvantages of this cooler:
- Changes in the current hydraulic system. Because the fan is powered by a hydraulic engine.
2.6.4. Chosen cooling unit
To select a definite cooling unit, a method is used where the three units are being tested with six important requirements. First the weigh factor of the requirements needs to be calculated. To calculate a weigh factor two requirements are compared see table 2.6.4.1. For example requirement 1 (Costs) against number 2 (Weight), here requirement 1 is more important than requirement 2. To find a final factor all the remaining requirements are compared to each other and the results are summed to an eventual factor see table 2.6.4.1. During the selection of the best oil cooler for this project the Kesselring method will be used partially. The three cooling units are only going to be tested with the six most important requirements. These three models are also shown in appendix 5:
Calculations with their specifications and dimensions.
Compared with requirement
Costs Weight Energy Modifications Dimensions
Noise
level
Score Factor
Requirements
Costs
-
1
1
0
0
1
3
2
Weight
0
-
1
0
0
1
2
1
Energy
0
0
-
0
0
0
0
1
Modifications
1
1
1
-
0
1
4
3
Dimensions
1
1
1
1
-
1
5
4
Noise level
0
0
1
0
0
-
1
1
With the necessary factors now known the three designs can be compared to each other to find the best design. During the assessments of the three designs, a choice can be made between the numbers 1 to 4. This depends how the design meets the regarding requirement. When a design doesn’t meet the requirement it gets a rating 1. A rating 4 will be given when the designs meets the requirement best. Rating 2 & 3 are also possible when it partially meets a requirement. This rating is then multiplied with the factor calculated in table 2.6.4.1, this way the most important requirements has the most participation to select the best oil cooling unit. The assessment of the three units is shown in table 2.6.4.1 and the results are figuratively shown in graph 2.6.4.
Designs
Rating
OK-ELD
OK-P
OK-ELH
Ideal
Costs
6
2
4
8
Weight
4
1
3
4
Energy consumption
2
3
4
4
Modifications
12
12
6
12
Dimensions
12
4
12
16
Noise level
2
3
3
4
∑
38
25
32
48
Relative ∑
79
52
67
100
Graph 2.6.6 shows that unit OK-ELD scored the highest of the three designs. The favorable dimensions and the least amount of modifications necessary ensured this design to be the best of the three. In the next section this unit and the cooling system will be elaborated further.
Table 2.6.4.1: Determine weigh factors
2.7. Detailed elaboration of the chosen concept
This section describes the elaboration of the design which has been chosen in the previous section. This design includes the implementation of the air cooling system (OK-ELD) in the return line of the hydraulic system. This design was chosen using the Kesselring method which is described in the previous sections. Figure 2.5.1 in section 2.5 shows the result of the Kesselring. The content of this section includes the calculations, chosen type of air cooler unit, necessary accessories, new hydraulic scheme and the total costs of the upgrade for the hydraulic oil cooling system. Recently, four new powerpacks where purchased. Documentation about these machines is easily accessible and very detailed. These powerpacks are equipped with hydraulic oil coolers, the available information about these oil coolers can be used for this project. The manufacturer of the installed oil coolers is HYDAC. On the website of this company there are a couple of calculation methods to select the correct OK-ELD type. Since oil cooling is quite a specialist job these calculations are used and documented in a spreadsheet. The formula listed below is used to calculate the power loss in the system caused by the heat exchange of the system.
The power loss of the current old powerpack system is calculated using the formula above and the result is 12kW. This counts for the six regarding powerpacks 1050-11/12/16/17/21 & 23. For more detailed information see appendix 5: Calculations. The data used in this equation is explained in appendix 5. The result of the formula listed above is necessary for the equation given below. This equation calculates the specific cooling capacity which the cooler needs to deliver to keep the oil at a safe 55°C. This is the maximum safe temperature of the hydraulic oil.
0
20
40
60
80
100
120
OK-ELD OK-P OK-ELH
Ideal
Sc
o
re
Cooler Units
Kesselring Table
Rel ∑
The specific cooling capacity which the cooling unit minimal needs to have is calculated. This is calculated using the formula on the previous page and after a 10% safety margin the result is 0.87kW / °C. This only counts for the six regarding powerpacks 1050-11 / 12 / 16 / 17 / 21 / 23. For more detailed calculations see appendix 5: Calculations. With the cooling capacity now known the correct cooler type can be chosen with the help of a supplied graph.
Graph: 2.7 shows that OK-ELD6 is the oil cooler which is necessary for this project. The graph shows a vertical line at 140 l/min. This value is the maximum flow produced by the main pump in the hydraulic system of the powerpack. Figure 2.7.1 shows the design of the OK-ELD6 oil cooler. The dimensions and specifications of the OK-ELD6 are made available in appendix 6: Chosen oil cooler.
To verify the results of the equations which were calculated above, an engineer at HYDAC has been contacted. After conversation by phone he provided a software program which calculates the best cooler for a given application. The results of this calculation program are shown in appendix 6: Chosen oil cooler. The results of this program are close to the same as the hand calculations made above.
After selecting the right oil cooling unit OK-ELD6 which is shown in figure 2.7.1 the accessories of the cooler where chosen. The accessories for the cooling unit are also shown in appendix 6: chosen oil cooler. These accessories are relevant for the safe operation of the cooling unit. Since the unit is not able to withstand pressure peaks, a bypass need to be implemented in the cooling unit. Also a thermostat and shock absorbers need to be installed to complete the design of the cooling unit.
Graph 2.7: Selection of OK-ELD cooler
The cooling unit is able to start and stop the cooling sequence with the help of a thermostat which is shown in Figure 2.7.2: Thermostat (AITF 50). This thermostat is mounted in one of the plug holes of the cooling unit OK-ELD6. The number 50 in the product number is the switch-in temperature of the cooling unit. To protect the cooling unit against pressure peaks in the system a by-pass is implemented in the cooling unit. This by-pass opens and then passes the cooling unit when the pressure rises above 6 bars see Figure 2.7.3. The cooling unit OK-ELD6 is able to withstand a pressure of 16 bars.
The unit is also equipped with mounting feet’s (FU) and shock absorbers (GP) which are shown in appendix 6: chosen oil cooler. These components were not relevant to present in this report because they have a simple function. With the knowledge of the added components a new order number is available which is:
OK-ELD6H / 3.1 / 24V / 1 / S / GP / FU / AITF 40 / IBP 6
The electric systems of the powerpacks are 24V since two 12V in series connected batteries are present within each powerpack. The price of one unit with all of its components is €1405, 40 see appendix 9: Quotation oil coolers. Six units have to be bought to provide oil cooling in the six regarding powerpacks. The hydraulic schemes are updated with the oil cooling unit implemented. These are presented in appendix 8: Updated hydraulic scheme. The lifetime of the electromotor from this unit is 16.000 operating hours.
Further in this research a new housing for the powerpacks will be designed. This means that a mounting position for the cooling unit is not known at this moment. During the design of a new housing the position for the cooling unit will be determent and this will be presented in chapter 4: Housing.
Figure 2.7.2: Thermostat
2.7.1. Wabco Air Dryers
This subsection describes the issues regarding the contamination of moisture in the hydraulic system. In the past the powerpacks weren’t equipped with air dryers these dryers keep the moisture within the ambient air outside the hydraulic system. This item was not part of the initial graduation project but has come to light during the length of this project.
In general the powerpack consist of a 650-700L hydraulic oil tanks which is connected to a pump that pressurizes the oil. This pressurized oil is send to an application which depends on the type of operation. These applications can either be strandjack, jacking or lifting operations.
This paragraph is used to explain why moisture is getting in the hydraulic oil/system when the air dryers are not used. When the hydraulic oil is sucked out of the tank by the pump, the oil level is lowered and the space which is created will be taken by ambient air otherwise a vacuum is created inside the oil tank. This vacuum may cause that the hydraulic oil can’t reach the pump. The air which takes the place of the drained oil is unfiltered ambient air which contains moisture, this moisture then gets inside the hydraulic system where it can cause serious damage.
The damage can be corrosion to the inside of the several hydraulic components. Other damage can be caused by air bubbles inside the hydraulic oil which can cause heavy damage to the fans of the hydraulic pump. This phenomenon is called cavitation, small air bubbles explode and damage the fan of the pump. Also the properties of the hydraulic oil are changed whereby it loses its lubricant film-strength it also gets a milky white color when too much moisture is mixed with the oil. Another big issue of moist inside the oil tank happens when working in extreme cold conditions, the water which is mixed with the oil gets frozen.
To prevent all of these problems the ambient air which gets sucked in the oil tank has to be filtered or dried. These air dryers are small cartridges which can be mounted on the tank. Inside these cartridges are filters which keep the moist and other particles out of the tank. Figure 2.7.4 shows the outside housing of the Wabco air dryer cartridges.
In the past a number of tests with these air dryers showed big improvements to the hydraulic system. This is the reason why a number of powerpacks has ‘two’ cartridges mounted on the tank.
During the length of this project this aspect of the powerpack has also been researched. Information about these filters wasn’t really available within ALE also the question why two filters where mounted could also not be answered. The get good answers to these questions the only option was to contact the fabricator of these filters ‘Wabco’. After a good conversation and e-mail traffic a lot of interesting information came to light. Such as the maximum air flow through these filters is 1500l/min per cartridges. This is more than enough for this application since the pump has a maximum capacity of 140l/min. This makes the use of two filters per powerpack a large overcapacity.
Documentation of these filters is listed in appendix 7.
Recommended by Wabco is to replace the filters every year. And when these filters are used regular it is
recommended to dry these cartridges every 2-3 months by heating them to 70-80°C for 12 hours. The Wabco ASP with coalescing filter is recommended because it also filters oil droplets. The price of one unit is €35.22 and should be mounted to all hydraulic powerpacks to lengthen the lifetime of the machine.
3. Noise reduction
This chapter describes the reasons and possibilities of noise reduction in the existing design of the six regarding powerpacks. It also gives the explanation and results of the calculations and the final result of the research to noise reduction. The preliminary research showed that all six powerpacks need the noise reduction.
3.1. General
There are several possible methods to reduce the noise level of the powerpack. This section describes which noise reduction systems are possible for the six regarding powerpacks. There are also many types of sound absorption materials available a definite will be chosen in this chapter. With the knowledge of the dimensions of the chosen sound absorption material the new housing of the powerpacks can be designed.
The reason the noise production needs to be lowered is because the sound emission at the moment is too high. Because of the high noise operating and working around these machines is not pleasant. Rules about sound levels for machines in Holland are written in machine safety standards ‘ARBO Law’. For workers who work with machines which produce a noise level higher than 85 dB (A) Personal Protection Equipment (PPE) have to be made available by ALE Heavylift B.V.
The (A) behind the unity dB stands for A-weighing. This has to do with the sensitivity of the human ear which is not equal for different frequencies of sound. So the A-weighing is a factor which depends on the frequency of the sound. Low frequency noises are difficult to hear, higher frequencies are easier to hear so here no correction is made. Research proved that a noise with the same volume and a frequency of 1000Hz is 70dB louder for a human ear then the same noise with a frequency of 10Hz.
The wish of ALE is to reduce the sound of the six regarding powerpacks to a sound level which meets the level of the newer powerpack units which produce a sound level (Lwa) of 102dB. Reaching the 102dB seems not possible since the engine and other components inside the new powerpack are improved during the last 20/30 years. This means that the sound output of these components can’t be reduced. However the sound level of the old powerpacks needs to be reduced as much as possible. Lwa is a value which is the sum of dB(A) together with a factor which is given in the regulations. This factor is not important since the difference between the measured dB(A) values is enough. Sound measurements of the new powerpacks can be used as a reference to the old powerpacks. The new powerpacks are equipped with the sound absorption plates. The sound level can then be measured with the doors closed and open. The difference between them can then be used to find out what the influence of these plates is. With this in mind, the sound level of the old powerpacks equipped with absorption plates can then be estimated. It is also recommendable to research if all components which produce vibrations are equipped with shock absorbers. Because motion of components will then be reduced and this will result in a lower sound level. This could include the application of rubber seals to all movable panels.
The mufflers of all six powerpacks are mounted on top of the housing. Research to the possibility and function of installing the exhaust inside the housing should also be done. Because this could contribute to a lower sound level which is emitted by the powerpack. To prevent heat being build up due to the fact that the exhaust is inside the powerpack, insulation of the exhaust has to be examined. This insulation reduces the heat and slightly reduces the noise output of the exhaust.
During this project a sound measurement was done to find the output noise of the powerpacks. Four positions around the powerpack are used for measuring. Two powerpacks where measured, 1050-11 which is an old powerpack and 1050-38 which is a new powerpack. Both powerpack where measured with doors closed en opened. The results of these measurements are listed in appendix 20.
The average noise level of the old powerpack with closed doors is 83.3 dB(A) this is 4.3 dB(A) higher as the new powerpack with the doors closed. The difference between the old and the new noise levels of the powerpacks when the doors are opened is 0.4 dB(A). This difference is quite small and not expected since the components of the older powerpack are dated compared to the new powerpack.
A noise increase of 10 dB(A) is perceived as a doubling of the volume for humans. This means that the lowering of 4.3 dB(A) is quite a big improvements since it will lower the sound level a quarter. This is only established with the improvement of the housing.
3.2. List of requirements
This section describes the requirements which are relevant for the noise reduction of the six regarding powerpacks. The external requirements are delivered by the company ALE Heavylift B.V. These requirements, which are listed below, are relevant for this project however these are not the only requirements for the powerpacks. The demands which are given below are mainly focused on the noise reduction of the powerpacks, since this is the scope of this chapter.
Functional list of requirements
The content of this list are the demands which are ordered and separated in groups. These groups describe the external, fixed and variable requirements of this project. Intern requirements can be added during the design process. External requirements
These requirements are formulated by the company and the possible involved classification bureaus. - The following powerpacks are the main focus for this project: 1050-11/12/16/17/21 and 23. All six
powerpacks are the scope during this chapter since all need the noise reduction.
- The noise level of the powerpacks needs to be reduced. Since it’s hard to predict the noise level with the adjustments presented in this project. The Lwa 102 dB which the new powerpack produces needs to be met as close as possible.
Fixed requirements
These are the requirements which every design must meet.
- The primary function of the powerpacks is the delivery of pressurized hydraulic oil to a system.
- The noise produced by the powerpacks needs to be reduced to a value which needs to approach the sound level of the new powerpacks which is Lwa 102 dB.
- To get a CE-marking, the regarding demands which are noted in the machine safety standard need to be satisfied.
Variable requirements
These are the requirements which every design needs to meet partially. These demands are the benchmarks, used to choose the best design.
- The costs of the design should be as low as possible.
- For mobility, the weight of the components should be as low as possible, since this influences the weight of the final design, which should be as low as possible.
- The lifetime of the chosen components should be as high as possible to extend the lifetime of the powerpack.
- The chosen insulation plates should have a high absorption factor.
Fabrication list of requirements
This list contains the demands which are relevant for the fabrication of the design. - The price of the necessary materials should be as low as possible.
- The assembly and installation costs should be as low as possible, it might be possible to assemble and fabricate within the workshop of ALE.
- The amount of components which are necessary for the designs, should be limited, this way the price can be lowered. However the function of the design should remain unchanged and kept within the requirements.
Environmental list of requirements
This list contains the demands which are relevant for the environment. These demands are set by the government and classifications bureaus every design needs to meet these requirements.
- The materials and the methods which are used to treat the materials used for the upgrade should be environmental friendly.
3.3. Sound reduction methods
This section describes the sound reduction methods for the six regarding powerpacks. Subsections have been made for insulation plates, research to exhaust muffler inside the housing and accessories such as seals and shock absorbers. With this data the costs for the noise reduction can be estimated this is presented in section 3.4.
3.3.1. Insulation plates
Since the plate surfaces inside the powerpack or quite thin insulation plates can be added to absorb the noise and vibration of the components inside. As stated before the function of these plates is the absorption of sound and vibrations. These plates are available in all kinds of sizes and types. This subsection describes the variety of insulation plates available. The definite insulation plate which will be used is also chosen in this subsection.
Three different manufacturers of insulation/absorption plates were contacted. On the website of these manufacturers, online catalogues were available. All the insulation plates of these three companies are listed in a spreadsheet shown in appendix 10: Insulation plates.
This spreadsheet is filled with all kinds of data of each plate. The absorption factor is given for six different
frequencies. This spreadsheet shows that low frequencies are very hard to insulate but as stated before noise with higher frequencies are louder to humans then noise with the same volume but lower frequencies. The insulation factor used in this table shows the dampening capacity of each plate at the given frequency. A high factor gives a high insulation which means a better sound reduction.
When all plates are implemented in the table, the differences between the absorption factors can be noticed.
Because not all plates are available for industrial applications a definite list of possible absorption plates is made. The content of this list includes the plates with a maximum thickness of 25mm and are resistant against fluids and oil. This table is also shown in appendix 10: Insulation plates.
This list shows the noise absorption plates which are compatible to use for the machine housing. When looking at this table it’s clear that the Merfocell PU has the highest values. But the insulation plate Merfocell GW is used for machine rooms and housings which need to carry a CE-mark. Since these powerpack are not allowed to carry a CE-mark because they are fabricated before the year 1995. Stated in the regulations of the ARBO Law is that machines fabricated before 1995 should follow the rules of the ‘Machine Directive’ as much as possible (See appendix 20). This means that the Merfocell GW insulation are the plates which are going to be used for this project. Figure 3.3.1 shows a picture of this material.
With a thickness of 25mm this material doesn’t score the highest insulation values but due to the fact it is fireproof it meets the requirements to carry the CE-mark. The fire retardant of this material is designed and tested according to: FMVSS 302 and UL94-HF1. Both are safety standards which are set up by classification bureaus in America. The plates consist of sound absorbing polyurethane foam provided with an impregnated glass fiber cloth. This layer provides protection against fluids, oil and is fireproof. To attach the insulation plates to the sheet metal an adhesive layer is made available to paste the insulation material to the sheet metal.
The entire inside of the powerpack will be covered with these insulation plates. In total a surface of 11 m² of insulation plates are necessary to cover the inside of one the powerpack. The costs of one m² of Merfocell GW costs €43.16 this means that the cover of one powerpack will cost around the €467,57. The total costs for all six powerpacks will lie around €2805,40.
3.3.2. Muffler inside the housing
The six powerpacks are all equipped with external exhaust mufflers because of the size these are mounted on top of the housing see figure 3.2.2. Since the exhaust is not isolated it produces a lot of noise and heat. To reduce the sound level of the exhaust it can be moved to the inside of the powerpack. However the temperature inside the powerpack rises when this modification is made. To solve this problem the entire exhaust together with the outlet manifold has to be insulated. This insulation reduces the heat output and slightly reduces the noise output. The temperature of the exhaust gasses will rise due to the insulation of the exhaust. The temperature inside the powerpack will be lowered which will result in a better performance of the engine.
The current silencers which are mounted on the powerpacks have immense dimensions. With a diameter of 300mm and a length of 1100mm they are too big to integrate them within the housing of the powerpack. A new exhaust silencer needs to be chosen.
Because the dimensioning of an exhaust system is a specific branch of technology a seller and manufacturer of exhaust systems was contacted. This company provided a calculation example for the dimensioning of an exhaust system. Because the current diameter of the current exhaust pipe is 4’’ this should be the value which will be calculated. With this diameter known an exhaust muffler for each engine can be chosen. The formula used to calculate the pipe diameter is shown below.
There are six different powerpacks. Three of them have the same engine, so for these three the calculation only has to be done once. The other three units need to be calculated separately. The calculations for the selection of the exhaust mufflers are shown in appendix 5.
The results of the calculations made in appendix 5 show that all six powerpacks have the same exhaust diameter which is 4’’ or 101,6mm. With this knowledge an exhaust muffler can be chosen with an inlet diameter of the same dimensions as calculated this means it is also 101,6mm.
Different fabricators of silencers have been contacted to find the best suitable silencer for this application. The fabricators which have been contacted include: Cowl, Merford, TIO and Phillips & Temro. After contacting these companies and several meetings with ALE mechanics an important additional issue came to light. Since safety is getting more and more important these days, the emission of glowing soot particles should be also be contained. Containing these glowing soot particles is done by a spark arrestor. When working in dangerous environments such as petrochemical plants, oil rigs etc. these spark arrestors have to be mounted on every engine. This is important because the glowing particles can ignite a fire or an explosion.
With this in mind the research to find the right combination of the exhaust muffler and spark arrestor is continued. After contacting the companies which are listed above an easy choice could be made. Since the companies Cowl, Merford and TIO only sells exhaust mufflers and spark arrestors separately, which have the same size this was not the best choice. Both the muffler and spark arrestor had the same size what made the required space for mounting very large.
Phillips & Temro was the only company of the 4 different contacted who had an exhaust muffler with an integrated spark arrestor. With four different categories available such as: industrial, residential, critical and hospital grade silencers, the choice was not hard to make. Since the powerpacks are used in all kinds of industrial environments the industrial grade silencer with build in spark arrestor has been chosen. The dimensions of the chosen silencer are Ø350x770mm which is smaller compared to the current silencer. It is a little bit thicker than the current but the length of the chosen silencer is more important since the old silencer would not fit inside. Documentation of the chosen exhaust muffler is shown in appendix 11.
The fabricator also made a quotation of the silencers and the requested accessories. This quotation is also shown in appendix 11. The requested accessories can be found in the quotation and includes: flex connectors, rain caps, 90° elbows, gaskets, and the mounting bands.
Because of the high temperatures produced by the exhaust, only non-flammable insulation can be used. There are several different products to insulate an exhaust such as glass and rock wool, heat blankets and thermo tape. The mineral wools can be used in combination with a heat sheet to keep it on its place. The heat blankets are custom made for each regarding application this makes it a very expensive product. The blankets are mostly used for high performance installations were the prevention of heat loss is very important. The thermo tape is the cheapest solution but has the lowest heat insulation therefore it is not chosen. The fabricator of the silencers is able to deliver heat blankets for these silencers. Therefore the insulation blankets are chosen. Exact prices of the heat blankets are not available at the moment since the length and elbows in the exhaust will be changed. These measurements are available when the adjustments to the exhaust system have been done. Documentation about these blankets is given in appendix 11. Figure 3.3.3 shows a heat blanket wrapped around a pipe.
To attach this product to the exhaust the heat blanket has to be wrapped around the pipes. After that it can be closed and secured with the help of a stainless steel wire. The exhaust temperature of a diesel engine is usually between the 500 and 600°C, this product is non-flammable and resistant against heats up to 1000°C.
3.3.3. Sound reduction accessories
This section describes and shows the additional accessories which are chosen during this project. These parts of the eventual design are small and can be explained in a composed section. These accessories include: Door and Panel seals and the ventilation roster.
Door Rubber
The door rubber which is used to prevent steel on steel contact has to be attached between the doors and the jambs. The rubber protects doors and panels against vibrations. The rubber is mounted to prevent noise or vibrations traveling through the open slots which are now sealed when this door rubber is applied. The door rubber has to be mounted with the integrated clamp profile which can be attached to plates from 1 to 3,5 mm, the barbs make sure the rubber isn’t able to move or come off in any way.
The contour of every jamb needs to be covered with this rubber profile. To attach this door rubber to all six powerpacks a total of 180m of rubber is necessary. The total costs of 180m are made available on the site www.gorubber.nl and will cost around €855 see appendix 12.
Ventilation Roster
The ventilation roster should be insulated against sound to lower the noise output traveling through the roster. The ventilation roster of the newer powerpacks can be used as a reference for this project. At first, it was intended to design a complete new ventilation roster. However during the preliminary research it became clear that there are companies who are specialized in the design and fabrication of these insulated ventilation rosters. Three different companies where contacted for documentation of their insulated ventilation rosters: Merford, Alara-Lukagro and Paroc.
The choice between the ventilation rosters wasn’t hard to make because the properties of the Merford insulated frames were much better. Important properties to choose the right ventilation rosters are: Dimensions, Noise insulation and the Airflow through the roster. Figure 3.3.5 shows a section view of three different rosters of Merford. The price and dimensions needed for the upgrade is listed in appendix 18.
Figure 3.3.4: Door Rubber
