JPH1062019A - Controller for compressor and refrigerator provided therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control two compressors in four modes without employing a plurality of pressure switches. SOLUTION: An input pressure in a common line for two compressors 3 (3L, 3S) is detected by one pressure sensor 6, and, on the basis of a pressure signal from the pressure sensor 6, a control unit 7 judges and controls the ON/ OFF operation of switches SW (SWL, SWS). The switches SW are connected to electromagnetic relays XC (XCL, XCS), and, by the operation of the electromagnetic relays, the supply of an electric power to the compressors 3, or the interruption of the supply thereof, is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pressure signal from a pressure detecting means provided on a low pressure side of a compressor having an electromagnetic valve for controlling the amount of refrigerant supplied to two or more compressors or evaporators. The present invention relates to a compressor control device capable of controlling the operation of the compressor based on the above and a refrigeration device including the same.

[0002]

2. Description of the Related Art Conventionally, in a supermarket or the like, a plurality of showcases are provided side by side, and different commodities are stored and sold in a storage room of each showcase. At this time, a refrigeration system is provided in the showcase to keep the products in each showcase at an appropriate temperature.

[0003] The refrigerating apparatus comprises an evaporator, an expansion valve, a compressor, a condenser, and the like. When there are a plurality of showcases, the evaporator and the expansion valve are provided for each showcase, and the compressor and the condensate are provided. The vessel may be provided separately as a common device.

[0004] The refrigerant is converted into a high-temperature and high-pressure vaporized refrigerant by a compressor, and the heat of the vaporized refrigerant is released to the outside air by a condenser to be a liquefied refrigerant. The liquefied refrigerant thus obtained is expanded by an expansion valve to generate a low-temperature refrigerant, and heat exchange is performed between the low-temperature refrigerant and the outside air, thereby cooling the outside air to generate cool air and storing the cooled air. The product in the room is cooled so as to be in a predetermined temperature range.

FIG. 5 is a diagram showing a configuration of a compressor in such a refrigerating apparatus. In FIG. 5, two compressors C (CL, CS) having different compression capacities and a pressure switch SP (SP) are shown.
L, SPS) are connected to the power supply line. Note that a switch SW is connected to the power supply line.

[0006] The pressure switch SP detects the pressure on the low pressure side (hereinafter referred to as the input side) of the compressor C. The operation of each compressor C is controlled by the pressure on the input side of the compressor C (hereinafter, referred to as input pressure) for the following reason.

That is, the operation of the compressor C should be controlled by the temperature of each storage room. However, when the temperature of the storage chamber is high, the temperature of the refrigerant in the evaporator increases significantly, so that the pressure on the output side of the evaporator increases. Increasing the pressure on the output side of the evaporator means increasing the input pressure of the compressor C. Therefore, if the operation of the compressor C is controlled by the input pressure of the compressor C, the temperature of the storage room can be controlled.

FIG. 6 shows how the pressure switch SP operates according to the input pressure. Here, the input pressure of the compressor C means the pressure of a common line when a plurality of compressors C are provided in parallel.

The compression capacity of the compressor CL is the same as that of the compressor CS.
Are described as a large compressor CL and a small compressor CS. Further, the ON operation pressure of the pressure switch SPL connected to the large compressor CL is set to SPL (ON),
The OFF operation pressure is set to SPL (OFF), and the ON operation pressure of the pressure switch SPS connected to the small compressor CS is set to SP.
S (ON), OFF operating pressure is SPS (OFF).

In such a situation, the input pressure gradually increases from the OFF operation pressure SPS (OFF), and the ON operation SPS
When (ON) is reached, the pressure switch SPS is turned ON, and the small compressor CS starts operating.

Thereafter, when the input pressure further increases and reaches the ON operation pressure SPL (ON), the pressure switch SPL is turned off.
After N operations, the large compressor CL starts operating.

In this way, the small compressor CS having a small compression capacity operates first, and if it is still too late, the large compressor CL having a large compression capacity also starts operating to lower the temperature of each storage room. It has become.

On the other hand, when the temperature of each storage chamber falls within a predetermined range, the input pressure decreases, and when it reaches the OFF operation pressure SPL (OFF), the compressor C in which the pressure switch SPL is turned OFF.
L stops. After that, the input pressure becomes OFF operation pressure SPS (O
FF), the pressure switch SPS is turned off and the compressor CS is stopped.

As described above, since the operation of the compressor is started or stopped by the ON / OFF operation of each pressure switch SP according to the input pressure, the temperature of the storage room can be properly maintained.

However, with the above configuration, it is not possible to control such that the large compressor CL operates alone. That is, the operation modes of the compressor C include a state where all the compressors CL and CS are stopped, a state where only the small compressor CS is operating, and a state where all the compressors CL and CS are operating. , Only the three compressors CL and CS are stopped, only the small compressor CS is operating, and the large compressor C
The four-mode control in a state where only L is operating and a state where all the compressors CL and CS are operating cannot be performed.

When such four-mode control is performed, FIG.
It is necessary to make a configuration as shown in FIG. This figure uses the same number of compressors C (CL, CS) as in FIG. 5, and a pressure switch SPL is connected in series to the large compressor CL, and a relay X is connected in parallel with the large compressor CL. ing.

The small compressor CS having a small compression capacity includes:
The pressure switch SPS is connected in series, and the pressure switch SPM and the relay contact X are connected in parallel with the pressure switch SPS.
A circuit in which S and S are connected in series is connected.

When the relay X is energized, the relay contact XS is turned off, and when the energization is stopped, the relay contact XS is turned on. Further, the ON operation pressures of the pressure switches SPL, SPS, SPM and O
The FF operating pressure is set to SPL (ON) and SPS (O
N), SPM (ON), SPL (OFF), SPS (O
FF) and SPM (OFF).

In such a case, as shown in FIG. 8, when the input pressure gradually increases and reaches SPM (ON), the pressure switch SPM operates. At this time, since the relay contact XS is in the conductive state, the small compressor CS operates.

Thereafter, the input pressure increases and SPL (ON)
, The pressure switch SPL operates and the large compressor C
L starts operating. At this time, since the energization of the relay X is started, the relay contact XS is opened and the small compressor CS is stopped. Therefore, in this state, only the large compressor CL is operating.

The input pressure further increases, and the SPS (O
When the pressure reaches N), the pressure switch SPS operates and the small compressor CS operates. Therefore, in this state, 2
The two compressors CL and CS are operating at the same time.

When the large and small compressors CL and CS are operating together, the input pressure decreases and the OFF operating pressure SP
When the pressure reaches S, the pressure switch SPS is turned off and the small compressor CS is stopped.

When the input pressure further decreases, the OFF operation pressure S
When the pressure reaches PL, the pressure switch SPL is turned off to stop the large compressor CL, and the power supply to the relay X is stopped, so that the relay terminal XC is turned on. As a result, the small compressor CS starts operating.

When the input pressure reaches the OFF operating pressure SPM, the pressure switch SPM is turned OFF and the small compressor C
S stops, and all the large and small compressors CL and CS are stopped.

As described above, the three pressure switches SP
By using L, SPM, SPS, and one relay X, four-mode control can be performed.

Since the refrigerating apparatus may cause a short cycle operation in which the start and stop of the compressor C frequently occur depending on the set pressure value, the start of the compressor C is delayed for a predetermined time. I have. FIG. 9 is a flowchart of a refrigeration apparatus that has a delay time at the start of operation of the compressor.

At step S1, pressure is detected, and the routine proceeds to step S2. In step S2, it is determined whether the detected pressure is the stop pressure of the compressor C. If the detected pressure is the stop pressure, the process proceeds to step S3, and if not, the process proceeds to step S4.

When the operation proceeds to step S3, the compressor C is stopped and the operation returns to step S1, and when the operation proceeds to step S4, it is determined whether or not the operation start pressure of the compressor C is reached.

If the pressure is not the operation start pressure of the compressor C, the process returns to step S1. If the pressure is the operation start pressure, the process proceeds to step S5.

In step S5, it is determined whether a predetermined time has elapsed before starting the operation. If the predetermined time has elapsed, the operation of the compressor C is started in step S6 and the process returns to step S1, and if not, the process directly returns to step S1.

[0031]

However, in the above configuration, for example, in the case of performing four-mode control, three pressure switches and one relay are required, which causes a cost increase.

Further, when changing the ON operation pressure and the OFF operation pressure of the pressure switch SP, it is very troublesome because the user needs to change the set values for all the pressure switches SP.

Further, in the method in which the compressor is started with a delay of a predetermined time, even if all the compressors C have been stopped for a predetermined time after a long time defrosting, the delay time is secured at the start. Is performed as a routine. As a result, the cooling of the product may be delayed and the liquid back operation may occur.

Therefore, the present invention makes it possible to perform multiple mode control without using a plurality of pressure switches to achieve cost reduction, to simplify the change of the set value of the pressure switches, and to realize a compressor. It is an object of the present invention to provide a compressor control device that can start operation immediately after being stopped for a long period of time to prevent a delay in cooling or the like, and a refrigeration device including the same.

[0035]

In order to solve the above-mentioned problems, the invention according to the first aspect of the present invention relates to a compressor control device, wherein the refrigerant circulated from the evaporator for exchanging heat between the low-temperature refrigerant and the outside air is reduced to two.
At the time of compression by the above-described compressors, the refrigerant pressure in the common line on the low pressure side of each of the compressors is detected, and pressure detection means for outputting this as a pressure signal is provided.
Control means for judging and controlling the operation start or stop of each compressor.

That is, the input pressure of a common line in a plurality of compressors is detected by one pressure detecting means, and the control means judges ON / OFF operation of each compressor based on a pressure signal from the pressure detecting means. And control is performed.

According to a second aspect of the present invention, there is provided a compressor control device according to the first aspect of the present invention, wherein when the control means starts operation of any one of the compressors after all the compressors have been stopped for a predetermined time or more. The operation is immediately started.

That is, if the control means determines that all of the plurality of compressors have been stopped for a predetermined time, the start of any one of the compressors is started immediately without securing a delay time. It is characterized in that the cold air is generated promptly by starting.

According to a third aspect of the present invention, there is provided the compressor control device, wherein the control means has a memory for storing an operation condition when controlling the operation of each of the compressors based on the pressure signal. .

That is, each compressor is turned ON / OFF based on the pressure signal.
It is characterized in that the condition for turning off is stored in a memory in advance, so that the condition can be easily changed.

The invention according to a refrigeration apparatus of claim 4 is as follows.
An evaporator for exchanging heat between the low-temperature refrigerant and the outside air to cool the outside air, two or more compressors for compressing the refrigerant from the evaporator input through a common line to produce a high-temperature and high-pressure refrigerant, A condenser for releasing the heat of the high-temperature and high-pressure refrigerant to the outside air to generate a liquefied refrigerant; and an expansion valve for expanding the liquefied refrigerant to generate a low-temperature refrigerant. In a refrigerating device that blows air to a storage room to cool the stored material, a refrigerant pressure in a common line on a low pressure side of each of the compressors is detected, and pressure detecting means for outputting the detected pressure as a pressure signal; And a control means for judging and controlling the operation start or stop of each of the compressors.

According to a fifth aspect of the present invention, when the control means starts the operation of any one of the compressors after all the compressors have been stopped for a preset time or more, the control means immediately starts the operation. The operation is started.

According to a sixth aspect of the present invention, the control means has a memory for storing operating conditions of each of the compressors based on the pressure signal.

[0044]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of a refrigeration apparatus according to the present embodiment. The refrigeration apparatus is configured to supply refrigerant to a plurality of showcases.

The refrigeration system includes an electromagnetic valve 10 (10a, 10b, 10C) for adjusting the supply amount of the liquefied refrigerant, and an expansion valve 11 (11a, 11a) for expanding the liquefied refrigerant to generate a low-temperature refrigerant.
b, 11C), an evaporator 12 (12a, 12b, 12C) for exchanging heat between the low-temperature refrigerant and the outside air to generate cool air, an accumulator 2 for gas-liquid separation of the refrigerant exchanged with air in the evaporator 12, and the accumulator. Two compressors 3 (3L, 3S) for compressing the refrigerant from the compressor 2; a condenser 4 for radiating and liquefying the heat of the refrigerant compressed to a high temperature and a high pressure by the compressor 3 to outside air; The receiver tank 5 that stores the liquefied refrigerant and stably supplies the liquefied refrigerant, the pressure sensor 6 that is a pressure detecting unit that detects the pressure on the input side of the compressor 3, and the compressor 3 based on the pressure signal from the pressure sensor. Has a control unit 7 for controlling the operation of.

The solenoid valve 10, the expansion valve 11, and the evaporator 12 are provided in each showcase, and the others are integrated as a common device. The number of the above showcases, that is, the number of the evaporators 12 and the like is appropriately set as needed.

A memory (not shown) is provided in the control unit 7, and the ON / OFF of each compressor 3 is previously stored in the memory.
The condition is stored.

FIG. 2 shows the structure of the control means.
The control means includes a control unit 7 and switches SWS and SWL. Each of the switches SW is connected to an electromagnetic relay XC (XCH, XCL), and determines whether or not to supply power to each of the compressors 3 by operating the electromagnetic relay XC. OFF control is performed.

Then, the control unit 7 switches the corresponding switch SW (SWL, SW) based on the pressure signal from the pressure sensor 6.
S).

FIG. 3 shows an example of ON / OFF conditions of each compressor 3 stored in the memory, and shows a case where four-mode control is performed and a case where three-mode control is performed.

The use of the storage room in FIG. 3 is selected and specified by the user. That is, when changing the contents of the table, the user calls the data corresponding to the number (No) shown in FIG.

In the following description, the compressor 3L and the compressor 3L
The case where the compression capacity of S is different will be described, and the smaller one is described as a small compressor 3S and the larger one is described as a large compressor 3L.

With the above configuration, the pressure sensor 6 detects the input pressure of the compressor 3 and outputs a pressure signal to the control unit 7. The control unit 7 determines and executes the control of the switch SW from the table stored in the memory based on the pressure signal.

When a plurality of showcases are arranged side by side, the temperature range of each showcase differs depending on the product stored in each storage room. However, since the compressor and the like are commonly used, the temperature control corresponding to each storage room cannot be directly controlled by the operation state of the compressor.

In such a case, the solenoid valve 10 operates.
That is, by controlling the amount of the liquefied refrigerant supplied to each expansion valve 11 by opening and closing the solenoid valve 10, the evaporator 12 is controlled.
Controlling the amount of low-temperature refrigerant sent to the

Therefore, the ON / OFF operation of the compressor 3 is
Control is performed for the entire evaporator 12.
In this sense, the table shown in FIG. 3 is data assuming that each showcase is set in the same temperature range.

For example, in the case of the four-mode control shown in FIG. 3, when the storage room is used for a refrigerator, the following control is performed.

That is, when the input pressure gradually increases to 2.4 kgf / cm ² with all the compressors stopped, the control unit 7 operates the switch SWS. As a result, the electromagnetic relay XCL operates and the small compressor 3S starts operating.

The input pressure is further increased to 2.7 kgf / c
Upon reaching m ^2, the control unit 7 by turning ON the switch SWL as to turn OFF the switch SWS, to stop the small compressor 3S, to operate the large compressor 3L.

When the input pressure reaches 3.0 kgf / cm ² , the control unit 7 further turns on the switch SWL,
The large and small compressors 3L and 3S are operated together.

As described above, when all the compressors 3 are operated, the input pressure is reduced to 2.0 kgf / cm
^When it reaches ² , the switch SWS turns off and the small compressor 3S
Stops, and only the large compressor 3L operates.

The input pressure is further reduced to 1.5 kgf / c
When m ² is reached, the switch SWL is turned off and the switch SWS is turned on. Therefore, large compressor 3L
Stops the operation and the small compressor 3S starts the operation.

When the input pressure reaches 1.0 kgf / cm ² , the switch SWS is turned off and both the large and small compressors 3 stop.

By the way, when it is detected that the compressor 3 has been stopped for a long time (such as defrosting due to pump down), the compressor 3 is started without delay time.

FIG. 4 is a flowchart showing such processing. As shown in the figure, after the compressor 3 is stopped, if the start of the compressor is not started for, for example, 10 minutes, the compressor 3 is started without waiting for the elapse of the delay time.

That is, the input pressure is detected in step S11, and it is determined in step S12 whether or not the pressure is the stop pressure of the compressor 3. Then, in the case of the stop pressure of the compressor 3, step S
Proceeding to step S16, if the pressure is not the stop pressure of the compressor 3, the process proceeds to step S13.

When the process proceeds to step S16, the compressor 3 is stopped in step S16, and it is determined in step S17 whether the compressor 3 has been stopped for a predetermined time. If the predetermined time has not elapsed, the process returns to step S11. If the predetermined time has elapsed, the process proceeds to step S18, where "1" is set in the immediate start flag F and the process returns to step S11.

On the other hand, if the operation proceeds to step S13, it is determined whether or not the input pressure is the operation pressure of the compressor 3. If the input pressure is not the operation pressure, the process returns to step S11. If the input pressure is the operation pressure, the operation proceeds to step S14. .

In step S14, the content of the immediate start flag F of the compressor 3 is determined, and when the content is "1",
In step S19, the immediate start flag F is reset, and the process proceeds to step S20.

If the content of the immediate start flag F is other than "1", the flow advances to step S15 to determine whether or not the delay time has elapsed.

If the delay time has not elapsed, the process returns to step S11. If the delay time has elapsed, the process proceeds to step S20, where the compressor 3 is operated and returns to step S11.

As described above, when the compressor 3 is stopped for a predetermined time, the immediate start flag F indicating the fact is set, so that the start is started immediately when the input pressure reaches the start pressure of the compressor 3. By doing so, it is possible to prevent a delay in cooling the stored material.

It should be noted that not only the above method but also another method is
A method is also possible in which a signal indicating a long-time stop (defrosting) state is input to the control unit 7 so that the delay is not executed when the signal is input.

In this case, when the processing mode is changed so that the compressor is started without stopping for a long time and waiting for the delay time, the normal processing mode, that is, the processing mode for starting the compressor after waiting for the delay time, is used. Can be returned after all the compressors 3 have been started, or can be released when the pressure drops after the small compressor 3S has been operated and the small compressor is removed again.

In the above description, the case where each compressor is controlled by the pressure on the input side of a plurality of compressors has been described. However, even if one compressor is used, the compressor is connected to the evaporator. When an electromagnetic valve (for example, the electromagnetic valve 10 in FIG. 1) that supplies the amount of the supplied refrigerant is provided, the opening and closing of the electromagnetic valve may be controlled to a plurality of opening / closing degrees according to the input pressure of the compressor. Good.

[0076]

According to the first aspect of the present invention, an input pressure of a common line in a plurality of compressors is detected by one pressure detecting means, and based on a pressure signal from the pressure detecting means. , Control means is ON / O of each compressor
Since the control is performed by judging the FF operation, the number of parts can be reduced, the cost of the compressor control device can be suppressed, and the size can be reduced.

According to the second aspect of the present invention, when the control means determines that all of the plurality of compressors have been stopped for a predetermined time, any one of the compressors is started. The start-up is started immediately without any delay time, so that cold air is generated quickly. Therefore, after the compressor has been stopped for a long time, the cooling of the product is delayed according to the defrosting process. This has made it possible to prevent liquid back operation beforehand and extend the life of the compressor.

According to the third aspect of the present invention, since the control means is provided with the memory for storing the operating conditions of each compressor, it is possible to easily and centrally change the conditions. Became possible and convenience was improved.

Further, the invention relating to the refrigeration apparatus of claim 4 is as follows.
A single pressure detection means detects an input pressure of a common line in a plurality of compressors, and a control means determines ON / OFF operation of each compressor based on a pressure signal from the pressure detection means to perform control. Since the refrigeration system was configured using the machine control unit, it became possible to make the refrigeration system compact and reduce costs.

According to a fifth aspect of the present invention, when the control means determines that all of the plurality of compressors have been stopped for a predetermined time, the delay time is reduced when any one of the compressors is started. Since the start of the air is started immediately and the generation of cold air is started immediately without securing the temperature, it is possible to prevent the cooling of the product from being delayed by the defrosting after the compressor has been stopped for a long time. As well as being able to prevent the liquid back operation beforehand and extending the life of the compressor, the refrigeration system is configured using the compressor control device, so that the reliability can be improved.

According to the refrigeration apparatus of the present invention, since the control means is provided with a memory for storing the operating conditions of each compressor, it is possible to easily and centrally change the conditions. Convenience was improved because the refrigeration system was configured using the machine controller.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a refrigeration apparatus applied to the description of the present invention.

FIG. 2 is a configuration diagram of a control unit.

FIG. 3 is a diagram exemplifying a table indicating operating conditions of each compressor stored in a memory provided in a control unit.

FIG. 4 is a flowchart showing a procedure when starting operation of the compressor.

FIG. 5 is a diagram showing a configuration for performing three-mode control in the related art.

FIG. 6 is a diagram illustrating the operation of FIG.

FIG. 7 is a diagram showing a configuration for performing four-mode control in the related art.

FIG. 8 is a diagram for explaining the operation of FIG. 7;

FIG. 9 is a flowchart showing a procedure when starting operation of a compressor in the prior art.

[Explanation of symbols]

 2 Accumulator 3 (3L, 3S) Compressor 4 Condenser 5 Receiver tank 6 Pressure sensor 7 Controller 10 (10a, 10b, 10c) Solenoid valve 11 (11a, 11b, 11c) Expansion valve 12 (12a, 12b, 12c) Evaporator SW (SWL, SWS) Switch XC (XCL, XCS) Electromagnetic relay

Claims (6)

[Claims] When refrigerant circulated from an evaporator for exchanging heat between low-temperature refrigerant and outside air is compressed by two or more compressors, the refrigerant pressure in a common line on the low pressure side of each of the compressors is detected. A compressor control device comprising: pressure detection means for outputting the pressure signal as a pressure signal; and control means for judging and controlling the operation start or stop of each compressor based on the pressure signal. 2. The method according to claim 1, wherein the control means immediately starts the operation of any one of the compressors after all the compressors have been stopped for a preset time or more. The compressor control device according to claim 1. 3. The compressor control device according to claim 1, wherein said control means has a memory for storing an operation condition when controlling an operation of each of said compressors based on said pressure signal. . 4. An evaporator for exchanging heat between a low-temperature refrigerant and the outside air to cool the outside air, and at least two or more of the refrigerant from the evaporator input through a common line to be compressed into a high-temperature and high-pressure refrigerant. The evaporator, comprising: a compressor for generating a liquefied refrigerant by releasing heat of the high-temperature and high-pressure refrigerant to the outside air; and an expansion valve for expanding the liquefied refrigerant to generate a low-temperature refrigerant. A refrigeration system that blows the cool air generated in the above to the storage room to cool the storage, detects a refrigerant pressure in a common line on a low pressure side of each of the compressors, and outputs the pressure as a pressure signal; A refrigerating apparatus comprising: a compressor control device including: a control unit that determines and controls an operation start or stop of each of the compressors based on a pressure signal. 5. The method according to claim 1, wherein the control means immediately starts the operation of any one of the compressors after all the compressors have been stopped for a preset time or more. The refrigeration apparatus according to claim 4. 6. The refrigeration system according to claim 4, wherein said control means has a memory for storing operating conditions of each of said compressors based on said pressure signal.