JPH026983B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a refrigeration system, and more particularly, a bypass passage is provided in the middle part of the compression process in the cylinder chamber of a compressor and on the suction side of the compressor. is provided with an on-off valve that opens and closes the bypass passage, and the on-off valve is opened or closed by applying low pressure or high pressure of the refrigeration device to the back chamber of the on-off valve,
The present invention relates to a refrigeration system that controls the capacity of the compressor.

(Prior Art) Conventionally, in this type of refrigeration equipment, in response to a reduction in the refrigeration load, the opening/closing valve is opened to communicate the compression process intermediate section with the suction side of the compressor to reduce the capacity of the compressor. There are devices that perform so-called unload control. Therefore, when the expansion device constituting a part of the refrigerant circuit is formed by a single capillary reach tube, the amount of refrigerant flowing through the capillary reach tube is determined by the pressure difference between the condensation pressure and the evaporation pressure. If a capillary reach tube is selected that has a refrigerant flow rate that provides an appropriate degree of superheat during load operation, that is, so-called full load operation, then during the unload operation, an amount of refrigerant greater than the amount required for the unload operation flows through the capillary reach tube. The problem was that the evaporation pressure increased, resulting in a decrease in the performance of the heat exchanger and failure due to the inflow of liquid refrigerant into the compressor.
In addition, if a capillary reach tube is selected that has a refrigerant flow rate that provides an appropriate degree of superheat during the unload operation, only an amount of refrigerant less than the amount of refrigerant required for proper operation will flow through the capillary reach tube during the full load operation. First, there was a problem in that the evaporation pressure decreased and the degree of superheat increased, resulting in poor heat exchange in the evaporator and a decrease in refrigerating capacity.

Therefore, as a measure to prevent this problem, the expansion device is formed by interposing two capillary reach tubes in parallel, so that both are used during the full load operation, and one is used during the unload operation. It is conceivable to perform pressure reduction control of the refrigerant according to the refrigeration load.

(Problem to be Solved by the Invention) However, in this case, in order to control the capacity of the compressor, the solenoid valve that opens and closes the on-off valve and the second
This requires two valves, a control valve that allows or disables the flow of refrigerant into one of the capillary reach tubes, and the number of parts increases, the refrigerant circuit becomes complicated, and it is difficult to control both valves. The control system was also complicated, and there were many failure points throughout, making it unreliable and uneconomical.

Furthermore, from the standpoint of device reliability, if a high-pressure liquid refrigerant injection circuit is installed as a measure to prevent abnormal rises in discharge gas temperature, a valve is required to control the flow cutoff of this high-pressure liquid refrigerant. This also resulted in the problem of an increase in the number of parts.

The present invention was invented in order to solve the above problems, and the purpose is to control the opening and closing of the on-off valve for controlling the capacity of the compressor and the capillary by using only one control valve such as a solenoid valve. The object of the present invention is to ensure that both the pressure reduction control of the refrigerant by the tube and the injection control of the high-pressure liquid refrigerant can be performed without malfunction.

(Means for Solving the Problems) That is, as shown in FIG. A bypass passage 21 is provided at an intermediate portion of the compression process in the cylinder chamber 11a of the machine 1 and at the suction side of the compressor 1, and an on-off valve 22 for opening and closing the bypass passage 21 is provided in the bypass passage 21, and the on-off valve 22 back chamber 24
In the refrigeration system, the capacity of the compressor 1 is controlled to a small capacity or a large capacity by opening or closing the on-off valve 22 by applying low or high pressure of the refrigeration system to the expansion device 3. It is formed by interposing a first capillary reach tube 3a and a second capillary reach tube 3b in parallel, and one control valve V is provided on the inlet side of the second capillary reach tube 3b. A communication pipe 25 is connected between the two capillary reach tubes 3b and the back chamber 24 of the on-off valve 22, and the communication pipe 2
5 and the suction side of the compressor 1, an auxiliary communication pipe 32 having a third capillary reach tube 31 is connected, and by closing the control valve V, low pressure of the refrigeration system is applied to the back chamber 24. First
While the capillary reach tube 3a acts as an expansion device, by opening the control valve V, the high pressure of the refrigeration system is applied to the back chamber 24, and the first and second capillary reach tubes 3a and 3b are expanded. act as a device, and
A portion of the high-pressure liquid refrigerant is injected from the auxiliary communication pipe 32 into the suction side of the compressor 1.

(Function) As a result, when the control valve V is closed, the on-off valve 22 is opened and the compressor 1 is operated at a small capacity, and the refrigerant is depressurized in the first capillary reach tube 3a, while the control valve V is closed. When opened, the on-off valve 22 is closed, the compressor 1 is operated at a large capacity, and the first and second capillary reach tubes 3a,
The refrigerant is depressurized at step 3b, and a portion of the high-pressure liquid refrigerant is injected into the suction side of the compressor 1 through the auxiliary communication pipe 32.

(Example) Hereinafter, an example of the refrigeration apparatus of the present invention will be described based on the drawings.

What is shown in FIG. 1 is a schematic representation of the refrigeration system of the present invention. In FIG. 1, 1 is a rotary compressor having a capacity control mechanism 5, vessel 2, expansion device 3, and evaporator 4
A refrigerant circuit 6 is connected in series, and the discharged gas is condensed and liquefied in the condenser 2.
A refrigerant circuit is formed in which the pressure is reduced in the evaporator 4, the refrigerant is vaporized in the evaporator 4, and the refrigerant is sucked into the compressor 1.

As shown in FIG. 2, the rotary compressor 1 has a cylindrical body 7a with both ends connected to an upper lid 7b and a lower lid 7c.
A motor (not shown) and a cylinder block 9 are mounted on top of the housing 7, which is covered with a sealed housing 7.
The drive shaft 8 of the motor passes through the cylinder block 9 and drives the rotor 10 housed inside the cylinder block 9.
The cylinder block 9 is composed of a cylinder body 11 having a cylinder chamber 11a having a wall surface concentric with the axis of the drive shaft 8, a front head 12 and a rear head that close the cylinder chamber 11a. The rotor 10, which rotates eccentrically with respect to the axis of the drive shaft 8, is installed inside.

The compressor 1 is of a stationary blade type, and the rotor 10 includes a cam 1 extending integrally from the drive shaft 8 and having a cylindrical peripheral surface.
0a, and a roller 1 that fits on the outer periphery of the cam 10a.
0b, the axis of the cam 10a is eccentric to the axis of the cylinder chamber 11a, and the roller 10b has a length equal to the length between the respective heads 12 and 13, and one part of its outer circumferential surface is attached to the cylinder wall. Let them come into contact with each other.

A blade 14 is slidably attached to the cylinder body 11 in a guide groove formed in the body 11 as shown in FIG.
It is brought into sealing pressure contact with the outer circumferential surface of b. Also,
A suction port 16 and a discharge port 17 that open into the cylinder chamber 11a are provided at positions close to each other on both sides of the blade 14, and one end of the discharge port 17 opens into the housing 7. A discharge valve 18 supported on the front head 12 is provided. And suction port 16
A suction pipe 6a extending from the evaporator 4 of the refrigerant circuit 6 is connected to the upper cover 7b, and a discharge pipe 6b leading to the condenser 2 of the refrigerant circuit 6 is connected to the upper cover 7b.

The capacity control mechanism 5 provided in the compressor 1 has an intermediate pressure port 19 located in the middle of the compression process from the opening position of the suction port 16 to the opening position of the discharge port 17 in the cylinder chamber 11a.
A valve chamber 20 is provided which communicates with the port 19, and a bypass passage 21 which communicates from the valve chamber 20 with the suction port 16 is provided. An on-off valve 22 that opens and closes the on-off valve 22 and a spring 23 that always biases the on-off valve 22 in the open direction are installed, and the on-off valve 22 is opened and closed by pressure control of the back chamber 24 of the on-off valve 22, and the compression The capacity of the machine 1 is controlled to be small or large.

1, the expansion device 3 is formed by interposing a first capillary reach tube 3a and a second capillary reach tube 3b in parallel. A communication pipe 2 is provided between the control valve V and the second capillary reach tube 3b and the back chamber 24 of the on-off valve 22.
5, and further connect the communication pipe 25 and the compressor 1.
An auxiliary communication pipe 32 having a third capillary reach tube 31 is connected to the suction pipe 6a on the suction side. Then, by opening the control valve V, the high-pressure refrigerant from the high-pressure liquid pipe 6c is communicated with the back chamber 24, and closing the on-off valve 22, and by closing the control valve V, the back chamber 24 is opened. It communicates with the suction side and opens the on-off valve 22.

The control valve V is opened when the refrigeration load is in a large load range from full load to a predetermined intermediate load,
Further, the closing operation is performed when the refrigeration load is in a small load range below the predetermined intermediate load.

In FIG. 2, 28 is a connecting pipe for connecting the suction pipe 6a to the suction port 16, 29 is a joint pipe, and 30 is a connecting member for connecting the connecting pipe 25.
This serves also as a stopper function when the on-off valve 22 retreats.

However, in the above configuration, during refrigeration operation,
When the refrigeration load is in the large load range, the control valve V is held open, so that the high pressure liquid pipe 6
The high-pressure refrigerant c communicates with the back chamber 24 of the on-off valve 22 through the first branch pipe 26 and the communication pipe 25, presses the on-off valve 22 against the urging force of the spring 23, and opens the intermediate pressure port 19. Close the compressor 1
is a large-capacity operating state in which compression is performed throughout the compression process. In this case, the high-pressure refrigerant in the high-pressure liquid pipe 6c is reduced in pressure by the first capillary reach tube 3a, and communicated with the second capillary reach tube 3b via the first branch pipe 26 and the second branch pipe 27. The pressure is also reduced by the second capillary reach tube 3b. Furthermore, a part of the high-pressure liquid refrigerant flows into the third capillary reach tube 31 via the communication pipe 25 and the auxiliary communication pipe 32, and
It is depressurized by the capillary reach tube 31, flows into the suction pipe 6a, and is injected into the suction port 16 of the compressor 1. As a result, the discharged gas is not overheated, and the cylinder block 9 of the compressor 1 and the motor 8 can be maintained at appropriate temperatures. From the above, refrigerating operation can be performed reliably in response to the above-mentioned large load.

Further, when the refrigeration load falls to the small load range, the control valve V is switched to the closed state. As a result, the back chamber 24 of the on-off valve 22 is communicated with the suction side, so that the on-off valve 22 is connected to the spring 23.
It is pushed back by the urging force of the intermediate pressure port 19 and the intermediate pressure of the intermediate pressure port 19. Therefore, intermediate pressure port 19
is communicated with the suction port 16 via the bypass passage 21, and the compressor 1 enters a small capacity operating state in which partial compression is performed after the intermediate pressure port 19 in the compression process. Further, in this case, the pressure of the high-pressure refrigerant in the high-pressure liquid pipe 6c is reduced only by the first capillary reach tube 3a, and the amount of circulating refrigerant is reduced. As a result of the above, refrigerating operation can be performed reliably in response to the small load.

As described above, according to this embodiment, even if a capillary reach tube is used for the expansion device 3, only the opening and closing of one control valve V is controlled.
Capacity control by the compressor 1, refrigerant pressure reduction control by the first and second capillary reach tubes 3a and 3b, and high-pressure liquid refrigerant injection control can be performed without using a complicated control device. This can always be done efficiently and reliably. In addition, the reason why we decided to perform the injection of high-pressure liquid refrigerant when the compressor 1 is operating at a large capacity is because the compression ratio is higher than when operating at a small capacity, which causes the discharge gas temperature to rise and cause burnout of the compressor. In order to prevent This is to prevent losses from occurring and adversely affecting the growth coefficient.

Further, in the operation of the refrigeration system as described above, when the drive of the compressor 1 is stopped, the control valve V is closed, and the on-off valve 22 is automatically opened by the action of a spring, and the bypass passage is opened. 21 opens, the high and low pressures are quickly equalized, and the pressure can also be equalized by controlling the single control valve V without using a complicated control device. be.

Moreover, at the time of starting, the control valve V is closed for a certain period of time to reduce the starting load applied to the motor 8, thereby making it possible to start easily with a small starting current.

In the embodiment shown in FIG. 1, the first capillary reach tube 3a includes a case in which a plurality of capillary reach tubes are formed in series or in parallel so that the first capillary reach tube 3a has the same pressure reducing ability.

The refrigeration system of the present invention described above can be applied as a heat pump type to one that cools and heats an area to be air-conditioned.

(Effects of the Invention) As described above, the present invention provides the expansion device 3 as the first
Formed by interposing a capillary reach tube 3a and a second capillary reach tube 3b in parallel,
One control valve V is provided on the inlet side of the second capillary reach tube 3b, and a communication pipe 25 is provided between the control valve V and the second capillary reach tube 3b and the back chamber 24 of the on-off valve 22. The auxiliary communication pipe 32 having the third capillary reach tube 31 is connected to the communication pipe 25 and the suction side of the compressor 1, and the control valve V is closed. By applying the low pressure of the refrigeration system to the rear chamber 24 and causing the first capillary reach tube 3a to function as an expansion device, and opening the control valve V, the high pressure of the refrigeration system is applied to the back chamber 24 and the first capillary reach tube 3a acts as an expansion device. and causing the second capillary reach tubes 3a and 3b to act as an expansion device, and
By injecting a portion of the high-pressure liquid refrigerant from the auxiliary communication pipe 32 into the suction side of the compressor 1, opening and closing of one control valve V performs three controls according to fluctuations in the refrigeration load. Capacity control by machine 1, and
It is possible to provide a refrigeration system with a simple structure and high reliability, which can reliably perform both the pressure reduction control of the refrigerant by the capillary reach tubes 3a and 3b and the injection control of the high-pressure liquid refrigerant without malfunction.

[Brief explanation of drawings]

Figure 1 is a refrigerant circuit diagram showing an embodiment of the present invention, Figure 2 is a refrigerant circuit diagram showing an embodiment of the present invention.
The figure is a longitudinal sectional view of a rotary compressor. 1... Compressor, 2... Condenser, 3... Expansion device, 3a... First capillary reach tube, 3b...
...Second capillary reach tube, 4...Evaporator, 1
1a...Cylinder chamber, 21...Bypass passage, 2
2...Opening/closing valve, 24...Back chamber, 25...Communication pipe, V...Control valve, 31...Third capillary reach tube, 32...Auxiliary communication pipe.

Claims (1)

[Claims] 1 Compressor 1, condenser 2, expansion device 3, evaporator 4
A bypass passage 21 is provided at an intermediate portion of the compression process in the cylinder chamber 11a of the compressor 1 and at the suction side of the compressor 1, and the bypass passage 21 is provided with a refrigerant circuit in which the
An on-off valve 22 that opens and closes is provided, and the on-off valve 22 is opened or closed by applying low pressure or high pressure of the refrigeration system to the back chamber 24 of the on-off valve 22.
In the refrigeration system in which the capacity of the compressor 1 is controlled to a small capacity or a large capacity, the expansion device 3
is formed by interposing the first capillary reach tube 3a and the second capillary reach tube 3b in parallel, one control valve V is provided on the inlet side of the second capillary reach tube 3b, and the control valve V and the Second
A communication pipe 25 is connected between the capillary reach tube 3b and the back chamber 24 of the on-off valve 22, and a third capillary reach tube 31 is provided between the communication pipe 25 and the suction side of the compressor 1. Auxiliary communication pipe 32
By connecting and closing the control valve V,
By applying the low pressure of the refrigeration system to the back chamber 24 and causing the first capillary reach tube 3a to act as an expansion device, by opening the control valve V, the high pressure of the refrigeration system is applied to the back chamber 24. and causing the first and second capillary reach tubes 3a, 3b to act as an expansion device,
A refrigeration system characterized in that a part of the high-pressure liquid refrigerant is injected from the auxiliary communication pipe 32 into the suction side of the compressor 1.