JPH0626476A - Refrigerating device - Google Patents

Abstract

PURPOSE:To obtain a refrigerating device which supplies a proper amount of cooling medium to a cooling medium injection port of a. fixed scroll even when an operation condition is changed, by using an electronic expansion valve as a flow rate variable means. CONSTITUTION:A scroll compressor 40, a condenser 41, an expansion valve 43, and a cooler 44 are connected to a device. An electronic expansion valve 45, a temperature sensor 46, and a controlling part 47 are provided as flow rate variable means in case that a part of cooling medium liquid is supplied from an outlet of a condenser liquid line to a cooling medium injection port 32 of a fixed scroll 1 of the scroll compressor 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll compressor used in a refrigeration system and for compressing a refrigerant.

[0002]

2. Description of the Related Art FIG. 4 is a longitudinal sectional view of a conventional scroll compressor disclosed in Japanese Patent Laid-Open No. 2-212395.
In FIG. 4, reference numeral 1 denotes a fixed scroll in which a spiral protrusion 3 is provided on the lower surface of a base plate portion 2, and a discharge port 4 is opened in the center portion. Reference numeral 5 denotes a scroll protrusion 7 provided on the upper surface of the base plate portion 6, and an orbiting scroll combined with the spiral protrusion 3, and an oscillation shaft portion 8 is provided below the center portion. 9 is a suction port formed on the outer circumference between the scrolls 1 and 2, 10 is a compression chamber formed by the spiral protrusions 3 and 7, 11 is a main shaft, and an eccentric hole 13 is formed in a large diameter portion 12 at the upper end. Is provided,
The oscillating scroll 5 is oscillated through the oscillating bearing 14. An eccentric oil supply hole 15 is provided through the main shaft 11. When the main shaft 11 rotates, 16 is an orbiting scroll 5
Is an Oldham's joint that regulates so as to make a revolving motion that does not rotate, and 17 is a closed container that houses the compression mechanism part and the drive mechanism part, and is composed of a lower container 18 and an upper container 19.

In the above conventional scroll compressor, when the shaft 11 rotates, the orbiting scroll 5 becomes the Oldham coupling 1.
Rotation is blocked through 6 and revolves. As a result, the suction gas is taken into the compression chamber 10 via the suction 3, is gradually compressed, and is discharged from the discharge port 4. Further, in FIG. 4, 20 is a fluid bypass hole (hereinafter referred to as “bypass hole”) provided in the base plate portion 2 of the fixed scroll 1, 21 is an annular slit provided concentrically outside the bypass hole 20, 22
Is a valve seat provided on the upper end surface around the bypass hole 20, and a valve seat space 23 is formed above. Reference numeral 24 is a discharge hole provided in the base plate portion 2 and communicates with the outside of the base plate portion 2 from the annular slit 21. Reference numeral 25 is a circular plate-shaped bypass valve, 26 is a valve seat plug that is mounted on the base plate portion 2 and covers the valve seat space 23, and has a communication hole 27 in the center. Reference numeral 28 denotes a coil spring inserted in the slit 21, which brings the bypass valve 25 into close contact with the push-up valve seat plug 26 when the valve seat space 23 becomes low in pressure.
Reference numeral 29 is a pressure pipe that guides suction pressure and discharge pressure by switching a three-way solenoid valve (not shown) or the like. It is passed through and fixed by brazing.

In the scroll compressor, the fixed scroll 1
Since the spiral protrusions 2 and 3 of both the oscillating scroll 5 and the orbiting scroll 5 are combined to form a plurality of symmetrical compression chambers 10 at the same time, at least one pair of the bypass hole 20, the discharge hole 24, the bypass valve 25, and the pressure pipe 29 is provided. The pair of compression chambers 10 are provided at symmetrical positions. A three-way solenoid valve (not shown) when operating the compressor at maximum capacity without capacity control
The discharge pressure is introduced to the outer end of the pressure pipe 29 by switching the above. As a result, the pressure in the valve seat space 23 becomes the discharge pressure, and this pressure pushes down the bypass valve 25, closing the valve seat 22 and closing the bypass hole 20. Thus, the pressure fluid from the compression chamber 10 is pressure-fed from the discharge port 4 through the discharge pipe 31.

When the capacity of the compressor is controlled, suction pressure is introduced into the outer end of the pressure pipe 29 by switching a three-way solenoid valve (not shown) or the like. As a result, the pressure in the valve seat space 23 becomes the suction pressure. Since the bypass hole 20 is provided in the middle of the compression process of the compression chamber 10, the pressure of the compression chamber 10 having the bypass hole 20 is higher than the suction pressure. By the pressure of the compression chamber 10 and the spring pressure of the coil spring 28, the bypass valve 25 is pushed up and closely received by the valve seat plug 26, the bypass hole 20 communicates with the discharge hole 24, and the fluid in the compression chamber 10 is communicated. Is discharged to the outside of the fixed scroll 1, and the compression capacity in the compression chamber 10 is controlled. Reference numeral 32 is a refrigerant injection hole (hereinafter referred to as “injection hole”) provided in the base plate portion 2 of the fixed scroll 1, and is located in the adjacent compression chamber 34 inside the compression chamber 33 in which the bypass hole 20 is opened. ing. Reference numeral 35 denotes a refrigerant injection pipe, which is fixed to a flange 36 attached to the base plate portion 2, and has a communication hole 37 and an injection hole 3
2 is communicated with the upper container 19 and is passed through the pipe hole 38 of the upper container 19 and fixed by brazing or the like. The injection pipe 35 is connected from the liquid line at the outlet of the condenser through a suitable throttle 39 to supply the liquid refrigerant to the compression chamber 34. In FIG. 3, reference numeral 40 denotes a scroll compressor having the above-mentioned configuration, 41
Is a condenser, 42 is its liquid line, 43 is an expansion valve, and 44 is a cooler.

As shown in FIG. 4, of the compression chambers 10, a pair of symmetrical compression chambers 3 having fluid bypass holes 20 open therein.
The injection holes 32 are opened in a pair of symmetrical compression chambers 34 that are inward from 3 respectively. The injection hole 32 is located inside the spiral projection 1a by one turn with respect to the bypass hole 20. Therefore, the injection hole 32 and the bypass hole 20 do not communicate with each other, and the liquid refrigerant supplied from the injection hole 32 is compressed while evaporating without leaking from the bypass hole 20 to the low pressure space during the compression, and heat is removed. It is taken and discharged from the discharge port 4.
As a result, high compression operation can be performed even when capacity control is being performed. Further, the liquid refrigerant supplied to the compression chamber 34 does not leak from the bypass hole 20 side.

[0007]

In the conventional refrigeration system,
When a capillary is used as the flow rate varying means when a part of the refrigerant liquid from the liquid line at the condenser outlet is supplied to the refrigerant injection hole of the scroll compressor through the refrigerant injection pipe, the flow resistance becomes almost constant and the flow control range Is narrow, and since the opening of the valve is limited in the thermal expansion valve, the flow control range is narrow. Therefore, even if the flow rate of the refrigerant supplied through the refrigerant injection holes is appropriate in the low evaporation temperature range, the refrigerant flow rate increases in the high evaporation temperature range, the discharge gas temperature decreases, and the input increases.

Further, by connecting two capillary tubes in parallel, the flow rate of the refrigerant supplied to the refrigerant injection holes becomes appropriate, and the discharge gas temperature can be set to be appropriate at the upper and lower limits of the evaporation temperature. Since the required supply amount of the refrigerant increases when the pressure decreases and the compression ratio increases, the supply refrigerant flow rate is increased by switching the number of used capillary tubes by turning on and off the solenoid valve. Since it becomes almost constant, there is a problem that the flow rate of the supplied refrigerant is excessively increased at the time of switching, the discharge temperature is lowered, and the input is increased. In the operation near the switching evaporator temperature, the capillaries to be used are frequently switched, so that there are problems that disorder occurs and unstable operation occurs, and the reliability of the solenoid valve decreases. Further, when the number of capillaries is increased, the increment of input is reduced, but there is a problem that the number of parts is increased.

According to the present invention, by using the electronic expansion valve as the flow rate varying means, the discharge gas temperature is controlled so that it does not rise and is properly maintained, the reliability is improved, and the proper supply refrigerant amount is provided. An object of the present invention is to obtain a refrigerating apparatus that can obtain

[0010]

The refrigeration system of the present invention comprises:
A scroll compressor, a condenser, an expansion valve, and a cooler were connected, and part of the refrigerant liquid from the liquid line at the condenser outlet was provided on the base plate part of the fixed scroll of the scroll compressor. A refrigeration cycle in which a refrigerant injection pipe having an electronic expansion valve for supply is connected to a plurality of refrigerant injection holes symmetrically arranged with respect to the center, and a temperature sensor for detecting the refrigerant gas temperature discharged from the scroll compressor. And a control unit that controls the valve opening degree of the electronic expansion valve of the refrigerant injection pipe according to the change in the refrigerant temperature of the refrigerant discharged from the scroll compressor detected by the temperature sensor.

[0011]

According to the refrigerating apparatus of the present invention having the above means,
An electronic expansion valve as a flow rate varying means for supplying a part of the refrigerant liquid from the condenser outlet liquid line to the refrigerant injection hole of the fixed scroll of the scroll compressor, a temperature sensor for detecting the discharge gas temperature, and an electronic expansion valve A control unit for increasing / decreasing the valve opening degree of is provided, and by keeping the discharge refrigerant gas temperature constant, an appropriate refrigerant flow rate is supplied to the refrigerant injection hole of the fixed scroll, so that the input gas due to the discharge gas temperature dropping too much The increase is prevented.

[0012]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a configuration diagram of a refrigerating apparatus according to this embodiment.

In FIG. 1, 43 is an expansion valve and 44 is a cooler. Part of the refrigerant liquid from the liquid line 42 at the outlet of the condenser 41 passes through the refrigerant injection pipe 35, is throttled by the electronic expansion valve 45, and is provided on the base plate portion 2 of the fixed scroll 1 of the scroll compressor 40. It is supplied to the injection hole 32. For the opening degree of the electronic expansion valve 45, a signal from a temperature sensor 46 for detecting the discharge refrigerant gas temperature is increased / decreased by the control unit 47, and the electronic expansion valve 45 has a built-in stepping motor, for example,
The opening degree of the valve is increased or decreased by a driving means such as a pulse motor.

In the electric expansion valve 45, the responsiveness is improved by detecting the discharged refrigerant gas temperature by opening and closing the valve with an electric signal and using the temperature sensor 46 having a small heat capacity. Further, when the electronic expansion valve 45 is driven by compensating for the response delay due to the heat capacity of the temperature sensor 46, a better response characteristic can be obtained.

In the control unit 47, a deviation occurs between the change in the discharge refrigerant gas temperature detected by the temperature sensor 46 and the target refrigerant gas temperature (hereinafter referred to as the target temperature). This deviation is an unbalanced signal. Appearing, amplified by the control unit 47, the output signal is given to the electronic expansion valve, the valve opening of the electronic expansion valve changes so as to approach the target value, and the valve opening changes until the deviation disappears. Let

That is, the opening degree of the electronic expansion valve 45 immediately follows the change of the discharged refrigerant gas. Further, since the expansion valve opening degree is increased or decreased using the discharged refrigerant gas temperature as a parameter, it is unlikely to be affected by the valve opening error, the refrigerant state at the inlet of the refrigerant injection pipe 35, or the subcool temperature.

Example 2. In addition, the refrigerant injection hole 3 is provided in at least one compression chamber inside the compression chamber in which the bypass hole 20 provided in the base plate portion 2 of the fixed scroll 1 is opened.
2, the bypass hole 20 may be provided at a position not communicating with the suction port 9, and the refrigerant injection hole 32 may be provided at a position not communicating with the bypass hole 20. In this case, the refrigerant injection hole 32 moves to the high pressure side. However, even if the discharge temperature rises during overload, the electronic expansion valve 45 should follow the rise in the discharge temperature.
Since the valve opening degree of is increased, a proper flow rate is obtained in the refrigerant injection hole 32, and the discharge gas temperature is kept constant.

Example 3. Further, as shown in FIG. 2, when the bypass capillary tube 48 is provided in parallel with the electronic expansion valve 45, the discharge gas temperature decreases, and even if the electronic expansion valve 45 is fully closed, the refrigerant from the bypass capillary tube 48 is discharged. Since the refrigerant is supplied to the injection holes 32, the discharge gas temperature is kept proper.

[0019]

According to the refrigerating apparatus of the present invention, an electronic expansion valve, a temperature sensor, and a control unit are provided as flow rate varying means when a part of the refrigerant liquid is supplied to the refrigerant injection hole, and the discharge gas temperature is controlled. Since it is kept constant, an appropriate refrigerant flow rate is supplied to the refrigerant injection holes of the fixed scroll, so that it is possible to obtain a refrigeration system having a low input, good performance, and a wide operating range.

[Brief description of drawings]

FIG. 1 is a first embodiment of the present invention. FIG. 6 is a configuration diagram showing a refrigeration apparatus according to a second embodiment.

FIG. 2 is a configuration diagram showing a refrigerating apparatus according to Embodiment 3 of the present invention.

FIG. 3 is a configuration diagram showing a conventional refrigeration system.

FIG. 4 is a vertical sectional view of a scroll compressor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed scroll 10 Compression chamber 20 Fluid bypass hole 24 Discharge hole 25 Bypass valve 32 Refrigerant injection hole 35 Refrigerant injection pipe 40 Scroll compressor 41 Condenser 42 Liquid line 43 Expansion valve 44 Cooler 45 Electronic expansion valve 46 Temperature sensor 47 Control unit 48 Bypass capillary tube

Continued Front Page (72) Inventor Jun Nagata 6-5-66 Tehira, Wakayama City Mitsubishi Electric Engineering Co., Ltd. Itami Works Wakayama Branch Office

Claims (1)

[Claims] 1. A scroll compressor, a condenser, an expansion valve, and a cooler are connected, and a part of a refrigerant liquid from a liquid line at the outlet of the condenser is used as a base plate of a fixed scroll of the scroll compressor. To a plurality of refrigerant injection holes symmetrically arranged with respect to the central portion provided in the section, a refrigeration cycle in which a refrigerant injection pipe having an electronic expansion valve for supply is connected, and a refrigerant gas temperature discharged from the scroll compressor. And a control unit for controlling the valve opening degree of the electronic expansion valve of the refrigerant injection pipe according to the change in the refrigerant gas temperature discharged from the scroll compressor detected by the temperature sensor. Refrigerating device characterized by.