JPS5970890A - Cooler for capacity control compressor - Google Patents

Abstract

PURPOSE:To perform proper cooling in accordance to the operating capacity of compressor by providing two refrigerant liquid injection circuits conducted respectively to compression chamber and delivery gas path. CONSTITUTION:In first injection circuit 18, refrigerant liquid is injected at initial compression stroke where pressure in cylinder chamber is low while when pressure in the cylinder chamber 8a exceeds over refrigerant liquid pressure, the injection port is closed by the end face of roller 12. The refrigerant liquid flow is determined constant by such as resistance of a capillary tube 22. In second injection circuit 19, refrigerant liquid is injected through suction in accordance to increase of flow speed when delivery gas passes through narrow path section 17a. In other word, under low capacity operation where delivery gas flow is low, flow speed of delivery gas at said path 17a is low to lower suction thus to reduce refrigerant liquid flow. While under high capacity operation where refrigerant liquid flow is high, proper cooling can be performed continuously in accordance to the operating capacity.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a cooling device for a capacity control compressor that is incorporated into an air conditioner, etc. This relates to a device that enables proper cooling of the compressor.

[Technical background of the invention and its odes]

Capacity control pressure compressors have recently been used as compressors for air conditioners, etc., but the capacity of these compressors varies greatly between small-capacity lid operation and man@capacity operation. It is difficult to maintain proper cooling at all times. As a conventional cooling device for a compressor, an injection cooling device is known in which liquid refrigerant condensed in a condenser is introduced into a closed case of a compressor and evaporated, and the latent heat of vaporization is used to cool the liquid refrigerant. In this injection cooling device, the method for introducing liquid refrigerant into the sealed case is to provide an injection circuit in communication with the cylinder chamber and introduce the liquid refrigerant using the pressure difference between the liquid refrigerant pressure in the injection circuit and the cylinder chamber pressure. A narrow passage is formed in the discharge gas passage of a compression element, an injection circuit is connected to the narrow passage, and when the discharge gas follows the narrow curved blood path, the flow velocity increases and a suction effect occurs at this time. There is a method of using jH, and in general, front moss is used.

However, when each of the injection cooling devices mentioned above was used excessively alone in a grave control pressure phase machine, there were the following problems. That is, in the former injection cooling device, the flow rate of the liquid refrigerant injected into the cylinder chamber is constant due to the resistance in the injection circuit.

In the past, if this liquid refrigerant flow rate was set to suit small-capacity operation, the four machines would become hot during high-capacity operation, causing problems such as burnout of electric elements. If the setting is made to suit the capacity operation, the proportion of work to recompress the injected refrigerant increases during the small capacity operation, and the coefficient of performance decreases. On the other hand, in the latter type of device that utilizes an in-jet ejection cooling system, the flow rate of the discharge gas changes according to the capacity control, so the flow rate of the liquid refrigerant also changes, but in order to obtain a sufficient flow rate of the liquid refrigerant, the The passage must be made very narrow, which causes discharge resistance, increases the extinction force, and lowers the pj:m coefficient. It is also known to control the flow rate of liquid refrigerant by installing an expensive flow control valve in the injection circuit, as seen in Japanese Patent Application Laid-Open No. 54-150759, but this leads to a significant increase in cost and reduces reliability. [Object of the Invention] The present invention eliminates the above-mentioned conventional inconsistency, and makes it possible to appropriately cool each operating part of a compressor at a low cost without reducing the reliability of the coefficient of performance. One of the objectives is to obtain a cooling system for a compressor that can be controlled by the user.

[Summary of the invention]

The present invention provides a first liquid refrigerant injection 1g circuit that communicates with the cylinder chamber of the 1-pressure transport element in each part control pressure 4ij machine, and a second liquid refrigerant injection circuit that communicates with the narrow passage portion formed in the discharge gas passage of the compression element. This system is installed in combination with a liquid refrigerant injection circuit of Cooling can be performed, and failures such as burnout of electric elements can be prevented.

[Embodiments of the invention]

A cooling device for a capacity control compressor according to an embodiment of the present invention will be explained in detail based on the drawings.

In the drawing, a capacity control compressor 1. Concentrator 2゜Capillary tube 3. Even if the refrigeration cycle of an air conditioner is constructed by sequentially connecting the evaporators 4, the capacity iIJ control compressor 1 has an electric element 6 and a compression element 7 housed and fixed in a sealed case 5. is composed of a stator 6a and a rotor 6b. On the other hand, the compression element 7 is in the cylinder chamber 8
a, and an upper bearing 10 and a lower bearing 11 that are attached to the upper and lower end surfaces of the cylinder 8, cover the cylinder chamber 8a, and support a rotating shaft 9 having the rotor 6b fixed to one end thereof. are doing. Further, an eccentric large diameter portion 9a is formed on the rotating shaft 9, and a roller 12 is fitted into the eccentric large diameter portion 9a. Further, the lower bearing 11 is provided with a discharge hole 13 and a discharge valve 14, and a pulp cover 16 forming a discharge chamber 15.
is provided. Also, upper bearing 10. Cylinder 8. A discharge gas passage 17 is provided passing through the lower bearing 11, and a narrow passage portion 17a is formed in the middle of the discharge gas passage 17.

Furthermore, the capacity control compressor 1 includes a first liquid refrigerant injection circuit 18 that branches from between the condenser 2 and the capillary tube 3 and communicates with the cylinder chamber 8a, and a first liquid refrigerant injection circuit 18 that branches from between the condenser and the capillary tube. However, a second liquid refrigerant injection circuit 19 is provided which communicates with the narrow curved blood path 7a. It should be noted that -tt is input to the Hrj response element 6 via a frequency conversion device (not shown).
W is supplied, and by controlling the power frequency, the number of revolutions of the rotor 6b and rotating shaft 9 of the tunnel cable 6 can be controlled to H1J, and the capacity of the compressor can be controlled. Further, 20 is a discharge pipe, 21 is a suction pipe, and 22 and 23 are capillary tubes.

Next, the operation of the present invention will be explained. 'When power is supplied to the electric element 6, the controller 6b and the rotary shaft 9 rotate together as a unit, and a well-known cooling operation is performed. That is, the low-pressure gas refrigerant sucked into the cylinder chamber 8a from the suction If21 is compressed here and becomes sub-pressure gas refrigerant, which is then discharged from the discharge hole 13.
It is discharged into the discharge chamber 15 via the discharge valve 14. Next, this discharged gas passes through the discharged gas passage 17. It is fed into the condenser 2 via the discharge pipe 20. The discharged gas is condensed in the condenser 2, becomes a still-pressure liquid refrigerant, and is sent to the capillary tube 3, where it is depressurized and evaporated in the evaporator 4. The refrigerant evaporated in the evaporator 4 is sucked into the cylinder chamber 8a via the suction 121 again. Also, during this operation, the first and second
A liquid refrigerant is injected into the closed case 2 through the injection circuits 18 and 19 to cool the electric element 6 and the compression element 7. That is, in the injection circuit k1, the liquid refrigerant is injected due to the pressure difference at the beginning of the compression stroke when the cylinder chamber pressure is low, and the cylinder chamber 8a and the refrigerant therein are cooled. Further, when the pressure in the cylinder chamber 8a becomes higher than the liquid refrigerant pressure, the injection port of the injection circuit 18 is closed by the end . It has become. The liquid refrigerant flow lid of the first injection circuit 18 is connected to the capillary tube 2.
It is determined by the resistance of the second class, and remains approximately constant even if the capacity of the compressor l is varied by changing the number of revolutions of the moving element. On the other hand, in the second injection circuit 19, the flow velocity of the discharged gas increases as it follows the narrow passage portion 17a, and liquid refrigerant is injected by the suction effect that occurs at this time. The flow rate of liquid refrigerant in the second injection circuit 19 changes depending on the operating capacity of the compressor. That is, during small capacity operation, the discharged gas flow rate per unit time is small, so the narrow passage portion 17a
The flow velocity of the discharged gas at +lJ is small, the suction action is also small, and the liquid refrigerant flow rate is reduced. On the other hand, during large-capacity operation, the discharge gas flow rate is high and the suction effect is large, and the liquid refrigerant flow rate increases. In the past, appropriate cooling can always be performed in accordance with the operating capacity of the compressor. Note that during small capacity operation, sufficient cooling can be performed by the first injection circuit 18, so cooling by the second injection circuit 19 is not necessary. Therefore,
The second injection circuit 19 can provide sufficient cooling during large-capacity operation, and the narrow passage can be made wider compared to a conventional system in which the second injection circuit 19 is used alone. Therefore, the discharge resistance becomes smaller, and it is possible to prevent the coefficient of performance from dropping significantly. Also,
The second injection circuit may be provided with an on-off valve that is closed during turn-it operation and opened during large-capacity operation. Furthermore, the first and second injection circuits may share a part of the circuit.

〔Effect of the invention〕

As explained above, the misfire 11j is caused by the first liquid refrigerant injection circuit communicating with the compression element σ cylinder tube of the h quantity control compressor, and the first liquid refrigerant injection circuit communicating with the narrow passage formed in the discharge gas communication path of the compression element. Since it is installed in combination with the liquid refrigerant injection circuit (2), it is possible to always perform appropriate cooling according to each operating capacity of the compressor without significantly lowering the coefficient of performance, and prevents problems such as burnout of electric elements. Blindness can be prevented. Moreover, the expensive flow rate t11. Compared to those using i-controlled valves, it is cheaper, more powerful, and has a simpler configuration, so reliability can be improved.

[Brief explanation of the drawing]

The drawing is a refrigeration cycle system diagram of an air conditioner, showing vertically a storage control compressor or cooling device according to an embodiment of the present invention. 2... Flexible case 6... Electric element 7...
Pressurized boron 8a... Cylinder chamber 17... Discharge gas communication path 17a... Narrow passage portion 18... First liquid refrigerant injection circuit 19... Second liquid refrigerant injection circuit substitute Ken Chika, Patent Attorney
Yu (1 person)

Claims (1)

[Claims] A first liquid refrigerant injection circuit that communicates with the cylinder chamber of the compression element is provided in a compression chamber controlled by each company, which houses an electric element and a compression element in a sealed case, and a A narrow passage is formed in the discharged gas blood path of the
A second liquid refrigerant injection lI communicating with the narrow passage portion! Capacity Vt1lJ characterized by providing l path
Control compressor cooling system.