GB2427660A

GB2427660A - A compressor with solenoid actuated capacity control inlet valves

Info

Publication number: GB2427660A
Application number: GB0513287A
Authority: GB
Inventors: Edwin Arthur Gittoes
Original assignee: Arctic Circle Ltd
Current assignee: Arctic Circle Ltd
Priority date: 2005-06-29
Filing date: 2005-06-29
Publication date: 2007-01-03
Anticipated expiration: 2025-06-29
Also published as: GB0513287D0; GB2427660B

Abstract

A compressor (2) comprising a first cylinder bore, a first piston operating in the first cylinder bore, a first suction port (8) for the first piston, a second cylinder bore, a second piston operating in the second cylinder bore, a second suction port (14) for the second piston, a cylinder head (16), a valve plate (18), and capacity control means for controlling the operational capacity of the compressor, the capacity control means comprising a first capacity control valve (22) for opening and closing the first suction port (8), a second capacity control valve (24) for opening and closing the second suction port (14), and solenoid-operated actuator means for controlling operation of the first capacity control valve (22) and the second capacity control valve (24), and the compressor thereby being such that it has a capacity control capability for individual cylinder bores. The compressor may be used in refrigeration apparatus, air conditioning apparatus, or heat pumps.

Description

A COMPRESSOR

This invention relates to a compressor. The compressor may be used in refrigeration apparatus air conditioning apparatus or heat pumps.

Compressors for use in apparatus for refrigeration or air conditioning are well known. The compressors generally operate with a fixed cubic capacity, which provides a constant output. However, refrigeration systems and air conditioning systems have varying load requirements due to changing heat loads and varying ambient conditions. The compressors have to be built to meet the maximum load requirements of the refrigeration systems and the air conditioning systems, and this means that the compressors are often oversized for the majority of the time when the load requirements are less than maximum.

In order to overcome the problem of compressors being oversized for the majority of their operational time, this is when their load requirements are less than maximum, it is known to provide the compressors with capacity control means for controlling the operational capacity of the compressors. The capacity control means is employed to match the output of the compressor more precisely with the requirements of the refrigeration system or the air conditioning system in which the compressor is installed.

Thus, for example, if the ambient temperature changes, then the heat transfer requirement changes, and therefore the work required by the compressor changes. The capacity control means enables the operational capacity of the compressor to be controlled.

Known compressors for use in apparatus for refrigeration or air conditioning may comprise pistons operating in cylinder bores, and a suction port by which refrigerant is introduced into the cylinder bores. The known capacity control means usually blocks the suction port to a bank of cylinders in one head of the compressor, and thus the known capacity control means blocks the flow of refrigerant to all the cylinder bores in this compressor head. This means that refrigerant does not flow into the cylinder bores, and therefore the pistons do not have anything to compress. With compressors which have all the pistons mounted in the same cylinder head, the compressor is thus only able to be in two conditions, i.e. fully working or not working at all. The known capacity control means uses a solenoid valve which magnetises a capacity control valve for the purpose of sealing the suction port which is in a valve plate. The capacity control is limited because shutting the suction port shuts off the refrigerant from the complete cylinder bank. For example, a compressor having two or three pistons operating in cylinder bores would have no capacity control as they would either be operating or not. Therefore the only capacity control available is 0 or 100%. Compressors having four cylinders operate in a V' configuration with two separate cylinder heads, each with a bank of two cylinders. Six cylinder compressors operate in a W' configuration with three separate cylinder heads, each of two cylinders. With four cylinder bores, it is possible to obtain 50% capacity control. With six cylinder bores, it is possible to obtain 33% capacity control and also 67% capacity control.

The smaller the capacity reduction, the larger the power saving as the compressor load can be matched more closely to ambient conditions.

Known compressors operating over capacity for a large percentage of the year makes them inefficient, especially on single compressor systems.

It is an aim of the present invention to reduce the above mentioned problems.

Accordingly in one non-limiting embodiment of the present invention there is provided a compressor comprising a first cylinder bore, a first piston operating in the first cylinder bore, a first suction port for the first piston, a second cylinder bore, a second piston operating in the second cylinder bore, a second suction port for the second piston, a cylinder head, a valve plate, and capacity control means for controlling the operational capacity of the compressor, the capacity control means comprising a first capacity control valve for opening and closing the first suction port, a second capacity control valve for opening and closing the second suction port, and solenoid- operated actuator means for controlling operation of the first capacity control valve and the second capacity control valve, and the compressor thereby being such that it has a capacity control capability for individual cylinder bores.

The compressor of the present invention has a capacity control facility for individual cylinder bores rather than for a bank of cylinders. This may be thought of as being achieved by segregating the head. The capacity control means used in the compressor of the present invention enables the compressor closely to match working conditions, and to make sure that the compressor only does the amount of work required. This therefore saves on energy as the power required by the compressor to do work is less.

Therefore because the compressor is able to match work requirements, the compressor of the present invention is more efficient than the above mentioned known compressors. The compressor may be for use in refrigeration apparatus, air conditioning apparatus, or heat pumps.

Preferably, the capacity control for individual bores is effected by providing the cylinder with a dividing wall which separates the first and the second suction ports.

Additionally, or alternatively, the capacity control for individual bores may be effected by providing the valve plate with a dividing wall which separates the first and second suction ports.

The solenoid-operated actuator means may comprise magnet means which is responsive to energisation of the solenoid-operated actuator means such that it repels the first and/or the second capacity control valves and causes the first and/or the second capacity control valves to seal the first and/or the second suction ports.

The magnet means may comprise a first actuator rod for the first capacity control valve, and a second actuator rod for the second capacity control valve.

The first and the second capacity control valves may each comprise a spring, the spring being such that it biases its associated capacity control valve to an open position in which its associated suction port is open.

The compressor will usually include a cylinder head gasket. The compressor will also usually include a valve plate gasket. The compressor will also usually include a capacity control gasket.

The compressor may be one which includes more cylinder bores and more pistons than the first and the second cylinder bores and the first and the second pistons.

The present invention also extends to apparatus for refrigeration or air conditioning when including the compressor of the present invention.

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 an exploded view of an upper part of a compressor; Figures 2 - 6 are perspective, top, underneath, side and end views respectively of a cylinder head as shown in Figure 1; Figure 7 is a top plan view of a cylinder head gasket as shown in Figure 1; Figure 8 is a top plan view of a valve plate as shown in Figure 1; Figure 9 is a top plan view of a valve plate gasket as shown in Figure 1; Figures 10 - 13 are perspective, side, right hand end and left hand end views respectively of a capacity control valve shown in Figure 1; Figures 14, 15, 16 and 17 are perspective, top, front and side views of a solenoid-operated actuator means as shown in Figure 1; and Figure 18 is a top plan view of a capacity control gasket as shown in Figure 1.

Referring to the drawings, there is shown the upper part of a compressor 2 for use in apparatus for refrigeration or air conditioning. The apparatus 2 comprises a first cylinder bore 4, a first piston 6 operating in the first cylinder bore 4, and a first suction port 8 for the first piston 6. The compressor 2 also comprises a second cylinder bore 10, a second piston 12 operating in the second cylinder bore 10, and a second suction port 14 for the second piston 12. The compressor 2 further comprises a cylinder head 16, a valve plate 18, and capacity control means 20 for controlling the operational capacity of the compressor 2.

The capacity control means 20 comprises a first capacity control valve 22 for opening and closing the first suction port 8, and a second capacity control valve 24 for opening and closing the second suction port 14.

The capacity control means 20 further comprises solenoid-operated actuator means 26 for controlling operation of the first capacity control valve 22 and the second capacity control valve 24.

The solenoid-operated actuator means 26 comprises magnet means 28 which is responsive to energisation of the solenoid-operated actuator means 26 such that the magnet means 28 repels the first and/or the second capacity control valves 22, 24 and causes the first and/or the second capacity control valves 22, 24 to seal the first and/or the second suction ports 8, 14. The magnet means 28 comprises a first actuator rod 30 for the first capacity control valve 22, and a second actuator rod 32 for the second capacity control valve 24.

The first and the second capacity control valves 22, 24 each comprise a spring 34. The spring 34 is such that it biases its associated capacity control valve 22, 24 to an open position in which the associated suction port 8, 14 is open.

As shown in Figure 4, the cylinder head 16 has a dividing wall 36 which separates the first and the second suction ports 8, 14.

As shown in Figure 1, the compressor 2 comprises a cylinder head gasket 38 and a valve plate gasket 40. As shown in Figure 18, the compressor 2 also comprises a capacity control gasket 42. Figure 1 shows how the capacity control means 20 is held together and bolted to the cylinder head 16 by bolts 44.

The compressor 2 is such that individual capacity control of each cylinder bore 4, 10 is able to be effected utilising a combination of the cylinder head 16, the valve plate 18, and the gasket 38, 40, 42 and the capacity control means 20. More specifically, the dividing wall 36 in the cylinder head 16 partitions the suction side into two parts, isolating the flow of refrigerant into each individual bore 4, 6, and ensuring that there is no cross flow. The cylinder head gasket 38 seals against the valve plate 18 for the purpose of isolating the first and the second suction ports 8, 14.

The first and the second suction ports 8, 14 are provided in the valve plate 18. The first and the second suction ports 8, 14 are aligned with an existing suction port in the compressor body, and are sealed by the valve plate gasket 40. The design of the valve plate 18 is able to utilise an existing discharge port (not shown) and the existing discharge port can be common to both the first and second cylinder bores 4, 10. With each of the first and the second suction ports 8, 14 individually sealed, the first and the second capacity control valves 22, 24 are able to operate individually to seal off one or other of the bores 8, 10, or both of the bores 8, 10. During operation of the solenoid-operated actuator means 26, the magnetic means 28 become energised and it repels the first and/or the second capacity control valve 22, 24 as appropriate to seal off the chosen first and/or second suction port 8, 14. Operating the first and the second capacity control valves 22, 24 thus allows either the bore 4, 10 to be sealed off, thereby removing the load. The facility of operating one or both of the first and second capacity control valves 22, 24 allows capacity control steps of 0%, 17%, 33%, 50%, 67%, 83% and 100% for a six cylinder compressor. This is achievable with having only one head part to the compressor, with the head part to the compressor having the cylinder head and the associated capacity control means of the present invention. By the present invention, the considerable increase in capacity control is effected by the above mentioned relatively simple changes. These changes allow standard valve plates and cylinder heads to be used on compressors where individual bore capacity control is required. Thus, for example, a standard head could be used on only one of six cylinder compressors, allowing the achievement of all of the above mentioned capacity control steps.

Still further, the present invention is able to be used to overcome higher levels of vibration associated with conventional compressors that have a conventional capacity control facility. More specifically, a conventional compressor with one head blocked off has an increase in its out of balance forces. As a consequent of this, the compressor suffers from increased levels of vibration. Utilising individual cylinder bore control by the present invention enables one cylinder from each head to be controlled, thereby reducing or eliminating additional out of balance forces.

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. Thus, for example, the compressor may have more than the first and second pistons 6, 12 operating in the first and the second cylinder bores 4, 10. Also, the compressor may be used in heat pump applications.

Claims

1. A compressor comprising a first cylinder bore, a first piston operating in the first cylinder bore, a first suction port for the first piston, a second cylinder bore, a second piston operating in the second cylinder bore, a second suction port for the second piston, a cylinder head, a valve plate, and capacity control means for controlling the operational capacity of the compressor, the capacity control means comprising a first capacity control valve for opening and closing the first suction port, a second capacity control valve for opening and closing the second suction port, and solenoid- operated actuator means for controlling operation of the first capacity control valve and the second capacity control valve, and the compressor thereby being such that it has a capacity control capability for individual cylinder bores.

2. A compressor according to claim 1 in which the cylinder head has a dividing wall which separates the first and the second suction ports.

3. A compressor according to claim I or claim 2 in which the valve plate has a dividing wall which separates the first and the second suction ports.

4. A compressor according to any one of the preceding claims in which the solenoid-operated actuator means comprises magnet means which is responsive to energisation of the solenoid-operated actuator means such that it repels the first and/or the second capacity control valves and causes the first and/or the second capacity control valves to seal the first and/or the second suction ports.

5. A compressor according to claim 4 in which the magnet means comprises a first actuator rod for the first capacity control valve, and a second actuator rod for the second capacity control valve.

6. A compressor according to claim 4 or claim 5 in which the first and the second capacity control valves each comprises a spring, the spring being such that it biases its associated capacity control valve to an open position in which its associated suction port is open.

7. A compressor according to any one of the preceding claims and including a cylinder head gasket.

8. A compressor according to any one of the preceding claims and including a valve plate gasket.

9. A compressor according to any one of the preceding claims and including a capacity control gasket.

10. A compressor according to any one of the preceding claims and including more cylinder head bores and more pistons that the first and the second cylinder bores and the first and the second pistons.

11. A compressor substantially as herein described with reference to the accompanying drawings.

12. Apparatus for refrigeration or air conditioning, when including a compressor according to any one of the preceding claims.