JPH0593548A - Refrigerator - Google Patents

Abstract

PURPOSE:To prevent overcooling of a compressor and to suppress wasteful consumption of power of the compressor by injecting a suitable amount of liquid refrigerant corresponding to a load of a refrigerator to the compressor. CONSTITUTION:A plurality of injection passages 2, 3 for introducing liquid refrigerant from the outlet of a condenser 12 into a compressor 11 are provided. Solenoid valves 21, 31 mounted therein are opened and closed in response to a compression ratio of the compressor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating device such as an air conditioner, a heat pump and a freezer.

[0002]

2. Description of the Related Art A refrigerant circuit of a conventional refrigeration system is shown in FIG. Compressor 11, condenser 12, throttling mechanism 13 and evaporator
A refrigerant circulation circuit is configured by connecting 14 through the refrigerant pipes in this order, and the refrigerant circulates in the refrigerant circulation circuit as indicated by solid arrows. The high-temperature, high-pressure gas refrigerant discharged from the compressor 11 enters the condenser 12, where it is condensed and liquefied to become a high-pressure liquid refrigerant. This liquid refrigerant enters a throttling mechanism 13 such as an expansion valve and is throttled there to adiabatically expand into a gas-liquid two-phase. Next, this refrigerant enters the evaporator 14, where it is evaporated and vaporized into a low-temperature and low-pressure gas refrigerant, which is sucked into the compressor 11 in this state and compressed again here.

Connecting the outlet of the condenser 12 and the compressor 11 1
A capillary tube 6 is provided in each of the injection flow paths 5.
Is installed. Then, a part of the liquid refrigerant liquefied in the condenser 12 is introduced into the compressor 11 through the injection flow path 5 and the capillary tube 6 as shown by the broken line arrow, and the compressor 11 is cooled so as to be overheated. It also prevents carbonization of lubricating oil.

[0004]

In the above conventional refrigeration system, the flow rate of the liquid refrigerant flowing through the injection flow path 5 is uniquely determined by the flow resistance value of the capillary tube 6, and the flow rate is high load of the refrigeration system. It is said to be a flow rate corresponding to the time. Therefore, when the refrigeration system has a high load,
A proper flow rate of the liquid refrigerant is introduced into the compressor 11, but when the refrigeration system has a low load, an excessive amount of the liquid refrigerant is introduced into the compressor 11, so that the compressor 11 is overcooled and its driving power is increased. Was wasted.

[0005]

The present invention has been invented to solve the above-mentioned problems, and its gist is to connect a compressor, a condenser, a throttle mechanism and an evaporator in this order. In the refrigerating apparatus comprising, a plurality of injection flow paths for introducing the liquid refrigerant at the condenser outlet into the compressor, an opening / closing means for opening and closing the plurality of injection flow paths, and a high pressure for detecting the discharge pressure of the compressor. Detection means, low pressure detection means for detecting the suction pressure of the compressor,
A control means for receiving the detection values of the high pressure detection means and the low pressure detection means, calculating the compression ratio of the compressor, and outputting the compression ratio to the opening / closing means that is predetermined corresponding to the compression ratio to open / close it. The refrigerating device is characterized by being provided.

[0006]

In the present invention, because of the above configuration, a plurality of injection flow paths are opened and closed according to the compression ratio of the compressor, and as a result, a large amount of liquid refrigerant is discharged at a high load with a large compression ratio. And a small amount of liquid refrigerant is introduced into the compressor at low load with a small compression ratio.

[0007]

1 is a system diagram of a refrigerating apparatus according to one embodiment of the present invention. The compressor 11, the condenser 12, the throttle mechanism 13, and the evaporator 14 are connected in this order via a refrigerant pipe. The high-temperature, high-pressure gas refrigerant discharged from the compressor 11 enters the condenser 12 as shown by the solid line arrow, where it is condensed and liquefied to become a high-pressure liquid refrigerant. This liquid refrigerant is a throttling mechanism
It enters 13 and when it is squeezed, it undergoes adiabatic expansion and becomes a gas-liquid two phase. Next, this refrigerant enters the evaporator 14, where it is evaporated and vaporized into a low-temperature low-pressure gas refrigerant. Then
This gas refrigerant is drawn into the compressor 11 and is compressed again there.

Between the outlet of the condenser 12 and the compressor 11, a plurality (
In the figure, two injection channels 2 and 3 are provided in parallel. Solenoid valve 21 in injection channel 2
Further, a capillary tube 22 is provided, and an electromagnetic valve 31 and a capillary tube 32 are provided in the injection flow path 3, respectively. The flow resistance value of the capillary tube 22 is set smaller than that of the capillary tube 32.

A high pressure sensor 45 for detecting the discharge pressure of the compressor 11 is attached to the discharge side, and a low pressure sensor 46 for detecting the suction pressure of the compressor 11 is attached to the suction side of the compressor 11. A controller 47 receives signals from the high-pressure sensor 45 and the low-pressure sensor 46 to calculate the compression ratio of the compressor 11, and outputs it to the solenoid valves 21 and 31 according to a predetermined control rule according to the compression ratio. Open and close this. That is, when the compression ratio is large, the solenoid valve 21 is opened and the solenoid valve 31 is closed. As a result, a part of the liquid refrigerant at the outlet of the condenser 12 is introduced into the compressor 11 through the injection flow path 2 which allows a large flow rate. When the compression ratio is slightly small, the solenoid valve 21 is closed and the solenoid valve 31 is opened. As a result, the liquid refrigerant is introduced into the compressor 11 through the injection flow path 3 which allows a small flow rate. When the compression ratio is smaller, the solenoid valves 21 and 31 are both closed. As a result, the introduction of the liquid refrigerant into the compressor 11 is stopped.

Thus, when the compression ratio of the compressor 11 is large, that is, when the refrigeration system is operated under a high load, the flow rate of the liquid refrigerant introduced into the compressor 11 increases, so that the compressor 11 is appropriately cooled and carbonization of the overheated lubricating oil of the compressor 11 is prevented. When the compression ratio of the compressor is small,
That is, when the refrigerating apparatus is operated under a low load, the flow rate of the liquid refrigerant introduced into the compressor 11 is reduced or becomes zero, so that the compressor 11 is not excessively cooled, In addition, waste of power for driving the compressor 11 is suppressed.

In the above embodiment, two injection channels 2 and 3 are provided, but it is also possible to provide three or more injection channels. Further, in the above embodiment, the flow rate of the liquid refrigerant flowing through the injection flow paths 2 and 3 is made different by changing the flow resistance values of the capillary tubes 22 and 32, but the injection flow paths 2 and 3 are the same. The injection flow paths 2 and 3 may be opened when the compression ratio is large, and only one injection flow path may be opened when the compression ratio is slightly small. When the compression ratio is small, both injection flow paths may be closed. In addition, solenoid valve 2
It is also possible to use one three-way valve instead of 1,31.

[0012]

According to the present invention, the compression ratio of the compressor is calculated from the discharge pressure and the suction pressure of the compressor, and the liquid refrigerant having an appropriate flow rate is passed through the injection flow passage selected according to the compression ratio. Since it is introduced into the compressor, it is possible to prevent overheating of the compressor, carbonization of the lubricating oil, and the like, and at the same time suppress overcooling of the compressor and waste of its driving power.

[Brief description of drawings]

FIG. 1 is a system diagram of a refrigerating apparatus according to an embodiment of the present invention.

FIG. 2 is a refrigerant circuit diagram of a conventional refrigeration system.

[Explanation of symbols]

 11 Compressor 12 Condenser 13 Throttling mechanism 14 Evaporator 2 Injection flow path 3 Injection flow path 21 Opening / closing means 31 Opening / closing means 45 High pressure detecting means 46 Low pressure detecting means 47 Control means

Claims (1)

[Claims] 1. A refrigeration system in which a compressor, a condenser, a throttle mechanism, and an evaporator are connected in this order, and a plurality of injection passages for introducing the liquid refrigerant at the outlet of the condenser into the compressor, and a plurality of the injection passages. Opening / closing means for opening / closing the injection flow path of the compressor, high pressure detecting means for detecting the discharge pressure of the compressor, low pressure detecting means for detecting the suction pressure of the compressor, and detection of the high pressure detecting means and the low pressure detecting means. A refrigerating apparatus comprising: a control means for receiving a value, calculating a compression ratio of the compressor, outputting the compression ratio to the predetermined opening / closing means corresponding to the compression ratio, and opening / closing the compression ratio.