JPS59119167A - Controller for cooling circuit - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device that can emergencyly open or close an electric expansion valve used in a refrigerant compression type cooling circuit to protect the cooling circuit in the event of an abnormality.

Figure 1 shows a conventional cooling circuit system and its control system.The gaseous refrigerant, which has been compressed to high pressure by the compressor and becomes high temperature, flows in the direction shown by the arrow in the figure and flows into the condenser. It radiates heat and becomes a high-pressure medium-temperature liquefied liquid. It is depressurized by an electric expansion valve ■ to become a low-pressure, low-temperature gas-liquid mixture state. It absorbs heat from the surroundings in an evaporator ■, evaporates into gas, and is sucked into a compressor ■. Ru. In addition, the refrigerant temperature 1゛E in the gas-liquid mixed state after being depressurized by the electric expansion valve ■ is detected by the temperature sensor ■,
Refrigerant temperature Tse at the outlet of the evaporator ■ or the compressor ■ suction port
Detected by the temperature sensor ■, input TE and Ts to the control device ■, and set △'I according to a predetermined program.
"==Ts-T" is calculated, and the opening degree of the electric expansion valve (■) is controlled so that ΔT becomes the target value.

In other words, normally, when the cooling circuit significantly deviates from its normal state, as shown in the flowchart in Fig. 2, the compressor is often stopped and waits for it to return to its normal state, as shown in Fig. 1. Conventional circuits provide such circuit protection. However, when the state value is slightly outside the normal range, it is not appropriate to take the emergency measure of stopping the compressor and completely stopping the cooling function, as this may cause damage. do not have.

The present invention was invented to solve the above-mentioned problems, and by changing the valve opening degree of the electric expansion valve (■), it is possible to escape from the abnormal state with only a slight effect on the cooling function. It is an object of the present invention to provide a control device for a cooling circuit that is capable of returning to its original state within a short period of time.

Examples of the present invention will be described in detail below.

The present invention uses a cooling circuit consisting of a compressor (1), a condenser (2), an electric expansion valve (2), and an evaporator (2) to collect the refrigerant temperature TE after being depressurized by the electric expansion valve (2) and the outlet of the evaporator (2) or the compressor. ■Measure the refrigerant temperature T at the suction port and transfer this value to the control device■
A refrigerant compression type cooling device in which the temperature difference between the two △T: Ts - TE is calculated within the control device ■ and the opening degree of the electric expansion valve ■ is controlled so that the temperature difference △T: Ts - TE becomes the target value. , when the opening degree of the electric expansion valve ■ is controlled and an emergency valve opening or closing command is received at the same time, the above △T
Irrespective of the above, the electric expansion valve (2) is configured to be opened or closed promptly with priority.

In the present invention, one or more sensors (not shown in FIG. 1) detect the state values of each part of the cooling circuit, input these values to the control device (2), and one or more of the detected values is determined to be normal. When the enclosure is broken, an emergency valve opening or closing command is given to the electric expansion valve (3). These emergency valve opening or closing commands are given priority over the immediate control command to the ΔT to open or close the valve.

In this way, according to one aspect of the present invention, the electric expansion valve ■ can be replaced by simply △
By using it not only to control the T but also to protect the circuit, it is possible to avoid an emergency stop of the compressor (2) as much as possible. This allows the cooling capacity of the evaporator (2) to be maintained and also eliminates the energy loss caused by stopping and starting the compressor, which is of great industrial value.

[Brief explanation of drawings]

Figure 1 shows a conventional cooling circuit and control device system.
2 and 8 are flowcharts showing side control programs for the cooling circuit, with FIG. 2 showing a conventional program and FIG. 3 showing a program according to the present invention. ■-Compressor ■=Injection compressor ■-Electric expansion valve ■=Evaporator ■■=Temperature sensor ■=Control device Patent applicant Taiheiyo Kogyo Co., Ltd. Figure 3

Claims (1)

[Claims] In the refrigerant compression cooling circuit, measure the refrigerant temperature TE by the temperature sensor ■ after the pressure has been reduced by the electric expansion valve ■, and the refrigerant temperature T by the temperature sensor ■ at the evaporator ■ outlet or compressor ■ suction port. This value is input to the control device ■, and the temperature difference between the two △T-=:Ts-TE is calculated within the control device ■ so that it becomes the target value, and the opening degree of the electric expansion valve ■ is controlled. At the same time, when an emergency valve opening or closing command is received, the cooling circuit is configured to immediately open or close the electric expansion valve ■, regardless of △T above. control device.