WO2004106741A1

WO2004106741A1 - Apparatus for connecting together at least two compressors used in refrigeration or air conditioning systems

Info

Publication number: WO2004106741A1
Application number: PCT/GB2004/002247
Authority: WO
Inventors: Edwin Arthur Gittoes
Original assignee: Arctic Circle Limited
Priority date: 2003-05-30
Filing date: 2004-05-26
Publication date: 2004-12-09
Also published as: DE602004009065D1; EP1629200A1; US20060153699A1; GB0312442D0; DE602004009065T2; EP1629200B1; ATE373779T1

Abstract

Apparatus for connecting together at least two compressors (17) used in refrigeration or air conditioning systems, which apparatus comprises a suction header (16), a discharge header, an oil header, oil return lines and an oil reservoir, which apparatus is such that the suction header (16), the discharge header, the oil header, the oil return lines and the oil reservoir are connected together in at least one main body component (31), and which apparatus is such that the compressors (17) are connected to the main body component (31) during use of the apparatus.

Description

APPARATUS FOR CONNECTING TOGETHER

AT LEAST TWO COMPRESSORS USED IN

REFRIGERATION OR AIR CONDITIONING SYSTEMS

This invention relates to multi-compressor installations commonly used in refrigeration or air conditioning systems. More especially, this invention relates to apparatus for connecting together at least two compressors used in refrigeration or air conditioning systems.

Known installations where more than one compressor is used are connected together using pipe systems for suction, discharge and oil pathways. The pipe systems are typically made from sections of high grade copper or steel, with standard fittings, valves and all other items connected, for example by braising, welding or other means.

Pipe sizes are chosen to be as small as possible in order to minimise on the cost of parts, and also to maximise on the resistance to high pressure or over pressure situations. Narrow pipe diameters cause high gas velocities, which increases losses and creates noise. The known pipe systems are complicated and time consuming to make. In addition, they require the use of skilled labour. Because of the large number of connections, there is an increased risk of leakage from the pipe systems. Complex designs inevitably result in high maintenance costs in order to ensure that pressure integrity is maintained. Often repairs or up-grades on site can only be carried out by skilled workers. In many cases, an official permit is required to work on the apparatus whilst it is in use. All of this increases time and cost.

It is an aim of the present invention to eliminate or mitigate the above mentioned problems.

Accordingly, in one non-limiting embodiment of the present invention, there is provided apparatus for connecting together at least two compressors used in refrigeration or air conditioning systems, which apparatus comprises a suction header, a discharge header, an oil header, oil return lines and an oil reservoir, which apparatus is such that the suction header, the discharge header, the oil header, the oil return lines and the oil reservoir are connected together in at least one main body component, and which apparatus is such that the compressors are connected to the main body component during use of the apparatus.

The apparatus of the present invention enables improvements to the design of multi-compressor installations, with the multi-compressor installations afforded by the present invention being simpler and easier to build.

As indicated above, the apparatus of the present invention is constructed from at least one main body component to which the compressors are attached. The main body component may be manufactured with an internal chamber, ports, valve cavities and other features normally required. The main body component can be manufactured in various ways, for example by casting. The apparatus of the present invention may be modular in function, allowing for the very rapid construction of multiple compressor systems, for example utilising two-six compressors without the need for welded or braised joints. The apparatus so constructed is able to have a large overall reduction in the number of joints compared to known pipe work system. The apparatus of the present invention enables high numbers of compressors to be connected together, this being due to the modular nature of the apparatus.

The apparatus of the present invention may be constructed in modular sections to be fully expandable in order to cope with a variety of system configurations. The apparatus does not need to be braised or welded as occurs with traditional systems. This means that on-site upgrades are realistic and practical possibilities. The apparatus of the present invention allows for simplified field modifications, and upgrades that do not require skilled welders and official permits, as are required for the above mentioned known systems. In addition, the main body component or components used in the apparatus of the present invention can be recycled, and so have an increased life cycle.

The apparatus of the present invention may be constructed to highly simplified designs that obviate the need for many parts used in known system. These parts used in known systems can be designed out of the apparatus of the present invention, or their function can be incorporated in the apparatus. Using such techniques, individual parts required can be drastically reduced, and joints can be reduced by as much as 70% compared with known systems.

Because of the low number of joints, and the fact that the joints can be made without using specialist techniques, the risk of leaks is reduced.

The apparatus may be manufactured from corrosion-resistant materials such for example as aluminium. The apparatus is preferably manufactured by casting but other manufacturing methods may be employed.

The apparatus of the present invention may incorporate a discharge header in one main body component suitable for a number of compressors. Additional compressors may be accommodated by attaching at least one other main body component, for example via a single joint. By this method, multiple compressor discharge headers may rapidly be created, using very few joints compared with traditional systems.

The suction header and/or the oil header may be incorporated in the same main body component as the discharge header, or they may have their own main body components which are designed for modular assembly. The apparatus provides for a wide variety of different combinations of suction, discharge and oil headers. Where non-useful heat could take place, this may be minimised in the apparatus of the present invention by the provision of ribs and chambers for providing insulation and/or separation between two regions of differing temperature.

The oil reservoir function in the apparatus of the present invention is able to be met without the need for a discrete oil reservoir. Increased chamber sizes in the main body component or components enable enough oil to be held in the apparatus in order to ensure that oil requirements are always met.

The apparatus of the present invention may include housings for all required service, shut-off control and regulating valves in suction, discharge and oil pathways.

The apparatus may include a plurality of gauge and pressure relief points.

The apparatus may be one in which internal cavity sizes are significantly larger than in known systems, thereby causing a reduced pressure drop between inlet and outlet sections of the apparatus. The reduced pressure drop itself may result in a reduced gas velocity that in turn leads to increased efficiency, and lower gas noise and vibration. Because of this, the apparatus is able to deliver improved compressor and system durability, together with energy savings due to the improved efficiency.

The apparatus may include suction accumulator functionality.

The apparatus may include an oil drain port and an oil sight glass.

As indicated above, the apparatus may be one which is in modular form for connecting the compressors together by extension modules.

The apparatus may be one in which the oil reservoir is located at compressor sump level. This enables the cross-sectional area of the oil header to be maximised, thereby reducing the effect of oil level fluctuations.

The apparatus may include a detachable oil separator. The apparatus may be one in which sufficient internal volume and flow area are provided so that gas balancing of more than three large compressors is possible in order to ensure consistent oil feed to each compressor without the need for an oil-regulating system. Such compressors may typically have a capacity of more than 100m³/hour.

The apparatus may include a bolt-on oil-feeder connector. Alternatively, the apparatus may be one in which oil feed and gas-balancing is combined in one cavity.

The apparatus may include a bolt-on suction filter assembly, the bolt- on suction filter assembly incorporating bypass valves and service valves.

The apparatus of the invention may include liquid sub-cooling means.

The apparatus may include a bolt-on oil separator, the bolt-on separator being such that it is cast complete with integral bypass or check valves and service valves.

An embodiment of the invention will now be described solely by way of example and with reference to the accompanying drawings in which:

Figure 1 is a functional schematic of apparatus of the present invention for connecting together at least two compressors used in refrigeration or air conditioning systems;

Figure 2 shows a schematic layout of the components required in the apparatus shown in Figure 1 ;

Figure 3 is comparable to Figure 1 and shows known apparatus that would be required to achieve what is achievable by the apparatus shown in Figure 1 ; and Figure 4 is comparable to Figure 2 and shows the components required in the apparatus shown in Figure 3.

Referring to Figure 1 , there is shown apparatus for connecting together at least two compressors used in refrigeration or air conditioning systems. The apparatus comprises a number of compressors 1 linked to each other and to various main body components by refrigerant pathways 2 and oil pathways 3. These pathways 2, 3 are provided in the main body components. The main body components are linked together via flanged joints 4. In the main body components, the function of shut-off valves 5, non-return valves 6 and pressure tappings/bleed points 7 are provided. The apparatus is also provided with sight glasses 8. A suction accumulator 9 is provided for each compressor 1, this being superior to providing one suction accumulator 9 for the entire apparatus.

The apparatus shown in Figure 1 also shows an oil separator 10, a suction filter/dryer 11, and end caps/blocks 12. T-joints 13 and bends 14 are also provided as shown.

The apparatus shown in Figure 1 does not require a discrete oil reservoir, since there is sufficient oil volume provided in the oil pathways of the apparatus.

Referring now to Figure 2, there is shown in Figure 2 by a dashed line 15 the functional circuit of Figure 1. Figure 2 shows by bold lines required physical main body components that are required by the apparatus of the present invention, there is provided a number of main body components incorporating several of the functions typically performed by several discrete components in a known conventional system. As can be seen from Figure 2, compressors 17 are connected to a suction header assembly 16, that incorporates the function of a suction accumulator 18 and a service shut-off valve 19. Provision for further numbers of compressors is made by modular extension main body components that provide the require functions. A suction header extension 20 is shown to provide the suction accumulator 18 and the service valve 19 function in an identical fashion to the suction header assembly 16.

In Figure 2, it will be seen that there is also provided a combined oil and gas-balance cavity, connected to the compressor via an oil-adapter arm 21. One shut-off valve 22 per oil-adapter arm 21 operates to shut-off gas balancing lines 23 and oil feed lines 24 to the compressor. Each oil-adapter arm 21 also incorporates a sight glass 25. For each compressor, there is provided a discharge adapter 26, incorporating a non-return valve 27. The apparatus of the present invention makes it possible to isolate and service this non-return valve 27, which would require additional valves in a known conventional system.

An oil adapter 21 and a discharge adapter 26 each connect to a distribution arm 28 that provides for all of the required internal cavities, and provides a discharge shut-off valve 29 and an oil/gas balance line shut-off valve 30.

The distribution arms 28 are connected to a main body component 31 that provides all the required internal cavities. The main body component 31 is connected at one end to an oil separator assembly 32. As for the suction header assembly 16, provision for more compressors are provided by a modular main body extension 33.

An oil separator assembly 32 is provided with required internals, a service valve 34, and a non-return valve 35. The oil separator assembly 32 also provides for connection to a refrigeration or air conditioning system via a pipe work adapter 36.

The main body component 31 is designed so that additional main body components can be added to further increase the size of the apparatus as required. This is effected by an end connection 37. Where no further extension is required to the apparatus, then a sealing end plate 38 is fitted. A similar part 39 is used at the end of the suction header extension 16.

A filter assembly 40 provides a suction filter/dryer function. The filter assembly 40 is attached to the suction header assembly 16. The filter assembly 40 incorporates a service valve 41. Provision is also made for connection to the refrigeration or air conditioning system via a pipe work adapter 42.

Pressure tapping points 43 are provided at convenient and useful locations throughout the apparatus.

Referring now to Figure 3, there is shown known conventionally constructed apparatus which exactly matches the functionality of the apparatus shown in Figures 1 and 2. Because of the methods of construction and other issues involved known to a competent professional installer, the number and position of the shut-off valves have been modified to achieve a functional match with the apparatus shown in Figures 1 and 2. Figure 3 is similar to Figure 1 , which many of the same parts. In Figure 3 it will be noticed that there is an oil line 44 and gas balance lines 45. Because these are provided by discrete pipelines, typically in copper, two shut-off valves 46 are required. An oil reservoir 47 is required for the apparatus shown in Figure 3 as there is not enough volume in the oil feed lines to accommodate the oil requirement of the system. For simplicity of illustration, an oil regulating system has not been shown, but one would be required.

In the apparatus show in Figure 3, an oil regulating system has not been shown for simplicity. Although the apparatus shown in Figure 3 is theoretically possible with existing technology, the gas-balancing of more than three large compressors is not possible due to limitations of current known designs. In reality, for apparatus of the size shown in Figure 3, an oil regulating system would be required. The oil regulating system would in turn require extra parts and costs. The extra parts would in themselves provide an additional leak potential due to an increased number of joints.

The disadvantages of the known apparatus shown in Figure 3 can clearly be seen from Figure 4. In Figure 4, bold lines are used to indicate individual parts. The circuit diagram shown in Figure 3 is included in Figure 4 as a dashed line 48.

Figure 4 shows that there are some pipe fittings for T-joints 49 and right angle bends 50. The apparatus shown in Figure 4 is simplified and, in reality, the apparatus shown in Figure 4 would require more fittings than those shown in order to run the pipe lines that are required. Time and effort would be needed in order to bend pipe work to ensure a coherent system.

Where a pipe run ends, a blanking plate 51 is required to seal the pipe. A blanking plate 51 would be required for each pipe end. Because the parts of the apparatus are supplied separately, there is a requirement for a plurality of joints to link these to the system.

Comparing Figure 4 to Figure 2, it is clear that the known conventional apparatus shown in Figure 4 requires far many more parts and joints than the apparatus according to the invention and shown in Figure 2. In the apparatus shown in Figure 2, there are 34 main joints between major parts, including blanking plates and access plates for the suction filter and oil reservoir float. There are 18 service valve seals, 5 non-return valve seals, 4 sight glass seals and 14 pressure tapping/drain points. The apparatus shown in Figure 2 thus has 75 potential locations for a leak.

In the known apparatus shown in Figure 4, there are 170 component joints (including end caps, copper pipe joints, joints to sight glass unit and access plates for the suction filter and reservoir float), 26 service valve seals, 5 non-return valve seals, 4 sight glass seals, and 14 pressure tapping/drain points. The apparatus shown in Figure 4 thus has 219 potential locations for a leak.

From a comparison of Figures 2 and 4, it will be seen that the leak potential of the apparatus of the present invention is nearly three times lower than for the known apparatus. In actual fact, a skilled person producing the apparatus of Figures 2 and 4 would probably require more joints than mentioned above, which would put the leak potential of the present invention at more than three times lower than for a known system.

It is to be appreciated that the embodiment of the invention described above with reference to the accompanying drawings has been given by way of example only and that modifications may be effected. The combination of multiple cavities and functions in the main body component or components can be achieved by many beneficial configurations, and the apparatus shown in Figures 1 and 2 is of one embodiment only. Other functionality may be provided in the main body component or components.

Claims

1. Apparatus for connecting together at least two compressors used in refrigeration or air conditioning systems, which apparatus comprises a suction header, a discharge header, an oil header, oil return lines and an oil reservoir, which apparatus is such that the suction header, the discharge header, the oil header, the oil return lines and the oil reservoir are connected together in at least one main body component, and which apparatus is such that the compressors are connected to the main body component during use of the apparatus.

2. Apparatus according to claim 1 and including housings for all required service, shut-off, control and regulating valves in suction, discharge and oil pathways.

3. Apparatus according to claim 1 or claim 2 and including a plurality of gauge and pressure relief points.

4. Apparatus according to any one of the preceding claims in which internal cavity sizes are significantly larger than in known systems, thereby causing a reduced pressure drop between inlet and outlet sections of the apparatus.

5. Apparatus according to any one of the preceding claims and including independent suction accumulator means for each compressor.

6. Apparatus according to any one of the preceding claims and including an oil drain port and an oil sight glass.

7. Apparatus according to any one of the preceding claims and which is in modular form for connecting the compressors together by extension modules.

8. Apparatus according to any one of the preceding claims in which the low pressure oil reservoir is located at compressor sump level.

9. Apparatus according to any one of the preceding claims and including a detachable oil separator.

10. Apparatus according to any one of the preceding claims wherein sufficient internal volume and flow area are provided so that gas balancing of more than three large compressors is possible to ensure consistent oil feed to each compressor without the need for an oil regulating system.

11. Apparatus according to any one of the preceding claims and including a bolt-on oil-feeder connector.

12. Apparatus according to any one of claims 1 - 10 in which oil feed and gas-balancing is combined in one cavity.

13. Apparatus according to any one of the preceding claims including a bolt-on suction filter assembly, the bolt-on suction filter assembly incorporating bypass valves and service valves.

14. Apparatus according to any one of claims 1 - 11 and including liquid sub-cooling.

15. Apparatus according to claim 9 and including a bolt-on oil separator, the bolt-oil separator being such that it is cast complete with integral bypass valves and service valves.