JP2646917B2 - Refrigeration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus used for a super showcase, a refrigerator, a thermostat, and the like.
In particular, the present invention relates to a refrigeration apparatus that requires high precision in temperature control in a refrigerator.

[0002]

2. Description of the Related Art Conventionally, as this type of refrigeration apparatus, for example, there is one described in Japanese Utility Model Publication No. 58-48987.
As shown in FIG. 6, the refrigerating apparatus includes a compressor 1, a condenser 2, a temperature-type expansion valve 3, and a cooler 4, which are connected by a pipe 5. A blower 6 is provided near the evaporator 4, and an evaporator 6 is provided. A temperature-sensitive cylinder 7 is disposed in an outlet pipe 5 of the vessel 4. The operation of the refrigerating apparatus is such that, for example, if the temperature of the liquid refrigerant in the evaporator 4 decreases, the temperature of the temperature-sensitive cylinder 7 decreases, and if the temperature falls below a predetermined temperature, the blower 6 operates to increase the blowing intensity. This keeps the temperature inside the refrigerator constant.

[0003]

However, in the above-mentioned refrigerating apparatus, the temperature of the refrigerant in the pipe 5 is detected and detected by the temperature-sensitive cylinder 7 to control the temperature in the refrigerator. On the other hand, it was indirect control. Therefore, although the response to the change in the refrigerant temperature and the pressure is fast, the temperature of the fin of the evaporator 4 changes first, and then the temperature of the refrigerant changes with the change of the air temperature in the refrigerator. There is a problem that the response is slow, for example, when the temperature of the hot cylinder 7 changes, and it is difficult to perform high-precision temperature control in which the internal temperature is controlled within a range of, for example, ± 0.5 to 1 ° C. from the set temperature. Was. Further, when the cooling load is small at the time of restarting after stopping the compressor, there has been a problem that the temperature inside the refrigerator rapidly drops, the compressor stops, and the compressor repeatedly starts and stops. When the compressor is restarted after stopping, the opening of the expansion valve is small, the suction pressure of the compressor drops rapidly, and the compressor stops or the opening of the expansion valve is large. There is a problem that the liquid returns and the overcurrent protector or the like operates, and the compressor stops.

In order to solve the above-mentioned problems, the present invention hastens the response of the refrigeration system to changes in the temperature in the refrigerator, and can control the temperature in the refrigerator with high accuracy with little fluctuation.
The purpose of the present invention is to obtain a refrigeration system with less running and stopping of the compressor.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a refrigeration system having a refrigerant flow path in which a compressor, a condenser, a decompression device, and an evaporator are connected by pipes. A motor-operated valve for adjusting the refrigerant flow rate is disposed, and a temperature detection unit that detects a surrounding temperature of the evaporator and generates a temperature detection signal is disposed near the evaporator, and the temperature detection signal and a predetermined set temperature are provided. A temperature comparison unit that compares a corresponding reference value and generates a signal corresponding to a difference between the two, a valve opening control unit that controls an opening of the electric valve by a signal of the temperature comparison unit, and a compressor after the compressor is stopped. When the valve is restarted, the valve opening correction section sets the opening of the electric valve to [the value when the compressor is stopped] + [predetermined value], and sets the [predetermined value] to [the value when the compressor is stopped]. And a predetermined value determining unit for determining the value.

The pressure reducing device forming the refrigerant flow passage is an electronic expansion valve, and the electronic expansion valve corresponds to a temperature of a suction pipe between the electric valve and the compressor and a pressure in the suction pipe. When the compressor is started and the electronic expansion valve control device that controls the difference from the saturation temperature to be a predetermined value, the opening of the electronic expansion valve is set to 1 with respect to the opening when the compressor is stopped. An electronic expansion valve opening correction unit is provided which starts at an opening that is a predetermined multiple exceeding the opening and controls the opening to be the opening when the compressor is stopped after a predetermined time.

[0007]

In the refrigerating apparatus according to the present invention, the temperature near the evaporator is detected by a temperature detector, the detected temperature is compared with a set temperature, and a definite value of the valve opening is output based on the result. In addition, when the compressor is restarted after stopping, the determined value of the valve opening is output as [the value when the compressor is stopped] + [the predetermined value] determined by the predetermined value determining unit. The temperature is controlled by adjusting the opening of the electric valve provided in the middle of the flow path.

Further, in the refrigeration apparatus according to the present invention, the pressure reducing device is an electronic expansion valve, and the electronic expansion valve is adapted to control the temperature of the suction pipe between the electric valve and the compressor and the pressure in the suction pipe. An electronic expansion valve control device that controls the difference between the saturation temperature and the corresponding saturation temperature to a predetermined value, and when the compressor is started, the opening degree of the electronic expansion valve is set to be 1 to the opening degree when the compressor is stopped. The opening degree of the electronic expansion valve is adjusted by an electronic expansion valve opening degree correction unit that starts at a predetermined multiple opening degree exceeding the above and controls the opening degree when the compressor is stopped after a predetermined time. .

[0009]

【Example】

Embodiment 1 FIG. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing a refrigeration apparatus according to the present invention. The refrigerant circuit includes a compressor 1, a condenser 2, an expansion valve 3,
The evaporator 4 is connected by a pipe 5, and a temperature-sensitive cylinder 7 is disposed at the outlet side of the evaporator 4, as in the related art, and the temperature-sensitive cylinder 7 is connected to the expansion valve 3 and is connected to the expansion valve 3. An opening is adjusted, and a blower 6 is arranged near the evaporator 4.
A first temperature detector 8 is arranged near the evaporator 4 and detects the ambient temperature of the evaporator 4. Reference numeral 9 denotes a temperature comparison unit which has a built-in comparison unit (not shown) for comparing a temperature detection signal from the first temperature detector 8 with a reference value set in accordance with a predetermined set temperature. The temperature detection signal is compared with a reference value, and a signal corresponding to the difference T is generated. 10 is
The valve opening control section controls the valve opening W of the electric valve 12 in accordance with a signal from the temperature comparison section 9. Also, 11
Is a valve opening correction unit, which determines the valve opening W of the electric valve 12 by [the value when the compressor 1 is stopped] + the predetermined value determination unit 20 when the compressor 1 is restarted after stopping. [Predetermined value]
It is assumed that. The motor-operated valve 12 is provided on a pipe on the outlet side of the evaporator 4 and adjusts the flow rate of the refrigerant flowing in the evaporator 4. In addition, the predetermined value determination unit 20 determines the [predetermined value] based on a value when the compressor 1 is stopped.

In the refrigerating apparatus, the refrigerant flowing through the evaporator 4 is adjusted by adjusting the opening of the motor-operated valve 12 depending on whether the temperature in the refrigerator is higher or lower than a predetermined temperature, and according to the degree of the temperature change. By controlling the flow rate, it is possible to quickly respond to a temperature change in the refrigerator.

FIG. 2 is a flowchart showing a control operation procedure of the valve opening control section 10 and the valve opening correction section 11 of the refrigeration system. Valve opening controller 1 for adjusting the opening of the electric valve 12
The definite value output from 0 is based on a signal from the temperature comparison unit 9. That is, in FIG.
When the compressor 1 is not restarted at 21, the process proceeds to step S23. In step S23, when a signal indicating that the internal temperature is higher than the predetermined temperature is input from the temperature comparison unit 9, the process proceeds to step S24, and the valve opening control unit 1
From 0, it is output to the motor-operated valve 12 so as to increase the valve opening W of the motor-operated valve 12 by a constant amount ΔW. Conversely, in step S23, when a signal indicating that the internal temperature is lower than the predetermined temperature is input from the temperature comparing unit 9, the process proceeds to step S25, and the valve opening degree W of the electric valve 12 is reduced by a fixed amount ΔW. It is output to the motor-operated valve 12 so as to decrease it.

In FIG. 2, when the compressor 1 is restarted in step S21, the process proceeds to step S22, and the valve opening of the electric valve 12 is set to [compressor] by the operation of the valve opening correction unit 11. One stop value] + [predetermined value] determined by predetermined value determining unit 20.

FIG. 3 is a flowchart showing a control operation procedure of the predetermined value determining section 20 of the refrigeration system. The determined value output from the predetermined value determining unit 20 is based on a signal from the valve opening when the compressor 1 is stopped. That is, the valve opening when the compressor is stopped to step S31 in FIG. 3 is the case of W ₁ or more, the process proceeds to step S32, the predetermined value is △ W _1. Further, the valve opening when the compressor is stopped in step S31 if less than W _1, the process proceeds to step S33. In step S33, the valve opening degree at the time the compressor stops when the W ₂ or more, the process proceeds to step S34, the predetermined value is △ W _2. In step S33, the valve opening degree at the time the compressor stops when less than W _2, the process proceeds to step S35, the predetermined value is △ W _3. In the present embodiment, the predetermined value is divided into three levels by the predetermined value determining unit 20, but the predetermined value can be determined in a similar manner regardless of whether the value is larger or smaller.

Although the present invention has been described with reference to the case where the temperature sensing cylinder 7 is connected to the expansion valve 3, the same effect can be obtained with an electronic expansion valve.

Embodiment 2 FIG. FIG. 4 is a diagram illustrating a circuit configuration of a refrigeration apparatus according to Embodiment 2 of the present invention. As shown in the figure, an electronic expansion valve 19 is provided instead of the expansion valve 3 of the first embodiment in FIG. Reference numeral 17 denotes a suction pipe communicating between the motor-operated valve 12 and the compressor 1, and reference numeral 13 denotes a second pipe for detecting the temperature of the suction pipe 17.
, A throttle device which communicates from the inlet liquid pipe of the electronic expansion valve 19 to the suction pipe 17, and a temperature immediately after exiting the throttle device 18 (saturation temperature corresponding to the pressure of the suction pipe 17) Is a third temperature detector for detecting the temperature. Fifteen
Is an electronic controller that controls the electronic expansion valve 19 so that the difference between the temperature detected by the second temperature detector 13 and the temperature detected by the third temperature detector 14 becomes a predetermined value. 1 is an expansion valve control device. Also, 16, when the compressor 1 starts, start with opening of the predetermined multiple of over 1 to stop when the opening stops the compressor 1 and the opening degree of the electronic expansion valve 19, the compressor after a predetermined time electronic expansion valve valve controlled to be opening at one stop is opening correction unit.

In the refrigerating apparatus, the opening degree of the motor-operated valve 12 is adjusted to control the flow rate of the refrigerant flowing through the evaporator 4 depending on whether the temperature in the refrigerator is higher or lower than a predetermined temperature. It responds quickly to temperature changes in the interior.

FIG. 5 shows an electronic expansion valve control device 1 for a refrigeration system.
5 is a flowchart showing a control operation procedure of the electronic expansion valve opening correction section 16. The determined value output from the electronic expansion valve control device 15 for adjusting the opening of the electronic expansion valve 19 is determined by the temperature detected by the second temperature detector 13 and the third temperature detector 14. Is based on the difference (SH1) from the temperature detected in step (1). That is, in FIG. 5, when the compressor 1 is not restarted in step S41, the process proceeds to step S43. In step S43, when a signal indicating that the difference (SH1) between the temperature detected by the second temperature detector 13 and the temperature detected by the third temperature detector 14 is higher than a predetermined value is input. The process then proceeds to step S44, where the electronic expansion valve controller 15 outputs to the electronic expansion valve 19 such that the valve opening G of the electronic expansion valve 19 is increased by a fixed amount ΔG. Conversely, step S43
In the case where a signal indicating that the difference (SH1) between the temperature detected by the second temperature detector 13 and the temperature detected by the third temperature detector 14 is lower than a predetermined value is input, Proceeding to S45, the electronic expansion valve controller 15 outputs to the electronic expansion valve 19 such that the valve opening G of the electronic expansion valve 19 is reduced by a fixed amount ΔG.

In FIG. 5, when the compressor 1 is restarted in step S41, the process proceeds to step S42, and the operation of the electronic expansion valve 19 is controlled by the operation of the electronic expansion valve opening correction section 16. opening degree with respect to the opening of the time stop the compressor 1 1
Starting at a predetermined double degree of opening exceeding
Is operated so as to stop when the opening of.

According to the present invention, there is provided a throttle device 18 which communicates from the inlet liquid pipe of the electronic expansion valve 19 to the suction pipe 17.
The temperature (saturation temperature corresponding to the pressure of the suction pipe 17) immediately after leaving the expansion device 18 is detected by the third temperature detector 14, but a pressure sensor is provided in the suction pipe 17,
The pressure may be detected and the pressure value may be converted to a temperature.

[0020]

Since the present invention is configured as described above, the temperature near the evaporator is directly detected by the temperature detector, and the detected signal is compared with the set temperature based on the detected signal. The determined value of the valve opening is output based on the calculated value, and when the compressor is restarted after the compressor is stopped, the determined value of the valve opening is determined by [the value when the compressor is stopped] + the predetermined value determined by the predetermined value determining unit. The opening degree of a motor-operated valve provided in the middle of the refrigerant flow path is adjusted according to the output. Therefore, the response of the temperature control to the change in the air temperature in the freezer or the like is accelerated, and the temperature in the freezer or the like is controlled with high accuracy with little fluctuation.

Further, since the present invention is constructed as described above, the electronic expansion valve is provided with a difference between the temperature of the suction pipe between the motor-operated valve and the compressor and the saturation temperature corresponding to the pressure in the suction pipe. When the compressor is started, the electronic expansion valve control device controls the opening of the electronic expansion valve at a predetermined multiple of more than 1 with respect to the opening when the compressor is stopped. Start up,
By the electronic expansion valve valve opening degree correction section that controls so as to opening when the stop compressor stop after a predetermined time, the opening degree of the electronic expansion valve is adjusted. Therefore, even when the compressor is restarted after it has stopped, the suction pressure of the compressor drops sharply, causing the compressor to stop or, conversely, a large amount of liquid returning to the compressor and the overcurrent protector to operate. And the compressor does not stop.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram of a refrigeration apparatus showing Embodiment 1 of the present invention.

FIG. 2 is a flowchart showing a control operation procedure of a valve opening control section and a valve opening correction section of the refrigeration apparatus shown in FIG.

FIG. 3 is a flowchart showing a control operation procedure of a predetermined value determining unit of the refrigeration apparatus shown in FIG.

FIG. 4 is a refrigerant circuit diagram of a refrigeration apparatus showing Embodiment 2 of the present invention.

5 is an electronic expansion valve control device for the refrigeration device shown in FIG. 4,
It is a flowchart which shows the control operation procedure of an electronic expansion valve valve opening correction part.

FIG. 6 is a refrigerant circuit diagram of a refrigeration apparatus showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Condenser 3 Expansion valve 4 Evaporator 5 Piping 8 1st temperature detection part 9 Temperature comparison part 10 Valve opening control part 11 Valve opening correction part 12 Motorized valve 13 2nd temperature detector 14 3rd Temperature detector 15 electronic expansion valve control device 16 electronic expansion valve opening degree correction unit 17 suction pipe 18 throttle device 19 electronic expansion valve 20 predetermined value determination unit

Claims (2)

(57) [Claims] 1. A refrigeration system having a refrigerant flow path in which a compressor, a condenser, a decompression device, and an evaporator are connected by piping.
A motor-operated valve provided in the middle of the refrigerant flow path to adjust the flow rate of the refrigerant in the evaporator, a temperature detector disposed near the evaporator and detecting a surrounding temperature of the evaporator to generate a temperature detection signal,
A temperature comparing unit that compares the temperature detection signal with a reference value corresponding to a predetermined set temperature and generates a signal corresponding to a difference between the two.
A valve opening control unit that controls the opening of the motor-operated valve based on a signal from the temperature comparing unit, and when the compressor is restarted after stopping, the opening of the motor-operated valve is determined by [the value when the compressor is stopped] +
A refrigerating apparatus comprising: a valve opening correction unit that sets a [predetermined value]; and a predetermined value determination unit that determines the [predetermined value] by using the [value when the compressor is stopped]. 2. A pressure reducing device comprising an electronic expansion valve, wherein said electronic expansion valve is a difference between a temperature of a suction pipe between said electric valve and said compressor and a saturation temperature corresponding to a pressure in said suction pipe. An electronic expansion valve control device that controls the opening of the electronic expansion valve to a predetermined value that exceeds 1 when the compressor is started and the opening when the compressor is stopped. 2. The refrigerating apparatus according to claim 1, further comprising: an electronic expansion valve opening degree correction unit that starts up at a predetermined temperature and controls the opening degree when the compressor is stopped after a predetermined time.