JP7133318B2 - Freezer and refrigerant recovery method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a refrigerating device and a refrigerant recovery method, and more particularly to a technique for recovering refrigerant in a refrigerating device.

As a conventional technique for recovering refrigerant in a refrigeration system, for example, the technique disclosed in Patent Document 1 is known. In Patent Document 1, an electromagnetic induction heating device is provided at the bottom of a compressor, and a refrigerant recovery circuit connected to the compressor is operated while the compressor is heated by the electromagnetic induction heating device, thereby completely removing the refrigerant. is disclosed.

JP-A-10-306961

However, when an electromagnetic expansion valve that controls the opening of the valve according to the rotation angle of the stepping motor is used as the expansion valve, it takes time to recover the refrigerant depending on the opening of the electromagnetic expansion valve when recovering the refrigerant. It is conceivable that the inconvenience of requiring That is, normally, refrigerant recovery is performed with the power supply of the refrigeration system turned off, so that the opening/closing control of the electromagnetic expansion valve cannot be performed. Therefore, when collecting refrigerant, if the refrigerant is collected with the opening degree of the electromagnetic expansion valve when the refrigerating device was turned off last time, it may take longer than necessary to collect the refrigerant depending on the opening degree when the refrigerating device was turned off last time. was there.

The technology disclosed in the present specification has been perfected based on the circumstances described above, and provides a refrigeration system and a refrigerant recovery method capable of efficiently recovering refrigerant in a refrigeration system equipped with an electronic expansion valve. do.

The refrigerating apparatus disclosed in the present specification is a refrigerating apparatus having a refrigerant circuit including an evaporator and a condenser, wherein an electronic expansion valve provided between the condenser and the evaporator and an operation by a user are performed. an instruction unit for generating an instruction signal for instructing recovery of the refrigerant circulating in the refrigerant circuit, a notification unit for notifying a user of the completion of preparation for refrigerant recovery, and a control unit for controlling the degree of opening of the electronic expansion valve. the control unit performs determination processing for determining whether or not the instruction signal has been received from the instruction unit; full-open processing for fully opening the electronic expansion valve when it is determined that the instruction signal has been received; full-open determination processing for determining whether or not the valve is fully opened; and notification processing for notifying the user of the completion of refrigerant collection preparation via the notification unit when it is determined that the electronic expansion valve is fully opened. .
According to this configuration, the electronic expansion valve is always fully opened when the refrigerant is recovered. Therefore, refrigerant can be efficiently recovered in a refrigerating device having an electronic expansion valve.

The above refrigeration apparatus includes a power switch that turns on and off the supply of power to the refrigeration apparatus, and an operation switch that operates the refrigeration apparatus, wherein the instruction unit is configured by the power switch and the operation switch, The instruction signal may be a signal generated when the power switch is turned on while the operation switch is turned on by a user.
According to this configuration, the power switch and the operation switch are existing parts that are provided in the refrigeration system in advance regardless of refrigerant recovery, and the instruction signal is generated without adding new dedicated parts for refrigerant recovery. be able to. That is, the refrigerant can be efficiently recovered in a refrigeration system having an electronic expansion valve without adding any parts.

Further, a refrigerant recovery method disclosed in the present specification is a refrigerating apparatus having an electronic expansion valve provided between a condenser and an evaporator of a refrigerant circuit, wherein the refrigerant recovers the refrigerant circulating in the refrigerant circuit. In the recovery method, the electronic expansion valve is fully opened according to a refrigerant recovery instruction from a user, the user is notified that the electronic expansion valve is fully opened, and after the notification that the electronic expansion valve is fully opened, the Start recovery of refrigerant.

In the above refrigerant recovery method, the refrigerating device includes a power switch for turning on and off power supply to the refrigerating device, and an operation switch for operating the refrigerating device. is turned on and the power switch is turned on.

According to the refrigerating apparatus and refrigerant recovery method of the present invention, refrigerant can be efficiently recovered in a refrigerating apparatus having an electronic expansion valve.

Schematic front view showing the appearance of a refrigeration apparatus according to the present invention Schematic diagram of the refrigeration system Schematic block diagram showing connection of control unit Flowchart showing processing related to refrigerant recovery Graph showing a reference example of opening/closing control of an electronic expansion valve

An embodiment according to the present invention will be described with reference to FIGS. 1 to 4. FIG. In this embodiment, as shown in FIGS. 1 and 2, an example in which the refrigerating device is applied to the ice maker 1 is shown, but the refrigerating device is not limited to the ice maker. That is, the ice maker 1 is an example of a refrigerating device. The refrigerating device may be any device provided with a refrigerant circuit including a compressor, an evaporator, a condenser, etc., and may be, for example, a freezer.

1. Configuration of Ice Maker (Refrigerating Device) As shown in FIG. The ice maker 1 also includes a housing 4 and a release mechanism 40 for releasing ice, as shown in FIG.

The housing 4 is provided with a power switch 2 for turning on/off power supply to the ice maker 1, and a display section 3 for displaying various displays related to operations. The power switch 2 is, for example, a breaker, and the display section 3 is, for example, a liquid crystal display (LCD). The display unit 3 is an example of a notification unit that notifies the user that the electronic expansion valve is fully open, which will be described later. Also, the discharge mechanism 40 is provided with three operation switches 41 for selecting and discharging the amount of ice to be discharged.

The power switch 2 and the operation switch 41 are an example of an instruction unit that generates an instruction signal Sc for instructing recovery of the refrigerant by a user's operation, which will be described later. In this embodiment, the instruction signal Sc is generated by turning on the power switch 2 while any one of the operation switches 41 is turned on by the user. In other words, the instruction signal Sc is an AND signal of the ON signal of the operation switch 41 and the ON signal of the power switch 2 .

The ice making unit 10 includes an ice making water tank 11, a pump motor 12, a water pipe 13, a sprinkler pipe 14, an ice making plate 15, and the like.

The ice-making water stored in the ice-making water tank 11 is supplied to the water pipe 13 by the pump motor 12 and sent to the sprinkler pipe 14 via the water pipe 13 . The ice-making water is supplied to the ice-making plate 15 through the sprinkler pipe 14, flows down the ice-making surface side of the ice-making plate 15, and returns to the ice-making water tank 11.例文帳に追加That is, the ice-making water is circulated by the pump motor 12 and cooled by the ice-making plate 15 during circulation to become ice.

The ice making unit 10 also includes a water supply pipe 16, a water supply valve 17, a water conduit 18, a drain valve 19, and the like. Ice making water is supplied to the ice making water tank 11 through the water supply pipe 16 and the water supply valve 17 , and unnecessary ice making water can be discharged from the ice making water tank 11 through the water conduit 18 and the drain valve 19 .

The refrigerant circuit 20 includes a compressor 21, a condenser 22, an expansion valve 23, an evaporator tube 24, a fan motor 27, etc., which are well-known structures. The compressor 21 compresses the refrigerant gas, and the condenser 22 cools and liquefies the compressed refrigerant gas. The expansion valve 23 expands the liquefied refrigerant, and the evaporation pipe 24 evaporates the expanded liquefied refrigerant to cool the ice making plate 15 . At that time, ice is formed on the ice making plate 15 . In this embodiment, the expansion valve 23 includes a stepping motor M whose rotation angle is controlled by the number of pulses of the pulse signal Ps, and an electronic expansion valve whose valve opening is controlled according to the rotation angle of the stepping motor M. is.

Refrigerant circuit 20 also includes a hot gas valve (HV) 25 and a bypass pipe 26 . The bypass pipe 26 connects between the compressor 21 and the evaporator pipe 24 , opens the hot gas valve 25 during the deicing operation, and supplies high-temperature refrigerant gas to the evaporator pipe 24 .

The refrigerant circuit 20 also includes an inlet temperature sensor S1 for detecting the refrigerant temperature evainT at the inlet of the evaporator tube 24, and an outlet temperature sensor S2 for detecting the refrigerant temperature evaoutT at the outlet of the evaporator tube 24. The refrigerant temperature evainT and the refrigerant temperature evaoutT are used when controlling the degree of opening of the electronic expansion valve 23 during the ice making operation, for example, by the degree of superheat ΔT. Here, the degree of superheat ΔT=evaoutT−evainT.

The refrigerant circuit 20 is also provided with a refrigerant pipe 28 and a charge port 29 that are connected to the compressor 21 and collect the refrigerant circulating through the refrigerant circuit 20 . The charge port 29 is connected to a known refrigerant recovery device during refrigerant recovery.

Control unit 30 includes CPU 31 and memory 32 . Various programs executed by the CPU 31 are stored in the memory 32 . In addition, the memory 32 stores various data obtained and calculated during execution of the program.

As shown in FIG. 3, the control unit 30 includes a power switch 2, a display unit 3, a pump motor 12, a compressor 21, an electronic expansion valve 23, a hot gas valve 25, an operation switch 41, an inlet temperature sensor S1, and an outlet temperature sensor S1. It is electrically connected to the temperature sensor S2 and the like.

2. Refrigerant Recovery Processing Next, refrigerant recovery processing for the ice maker, more specifically, refrigerant recovery preparation processing, which is executed by the controller 30 according to a predetermined program stored in the memory 32, will be described with reference to FIG. Note that the refrigerant recovery process includes a refrigerant recovery method.

In the refrigerant recovery process, the control unit 30, more specifically, the CPU 31, first receives an instruction signal Sc from the operation switch 41 and the power switch 2 (instruction unit). A judgment process (step S10) for judging whether or not an AND signal with a signal is received is executed. If the instruction signal Sc has not been received (step S10: NO), the controller 30 does not enter the refrigerant recovery mode and is in a standby state.

On the other hand, when the instruction signal Sc is received (step S10: YES), the control unit 30 shifts to the refrigerant recovery mode (step S20) and fully opens the electronic expansion valve (EEV) 23 (step S30). to run. In the full-opening process, the control unit 30 generates a pulse signal Ps with the number of pulses for fully opening the electronic expansion valve 23, and controls the electronic expansion valve 23 so that the opening is fully opened by the pulse signal Ps.

Next, the control unit 30 executes a full-open determination process (step S40) for determining whether or not the electronic expansion valve 23 is fully opened. Here, the CPU 31 determines whether or not the electronic expansion valve 23 is fully opened. For example, the CPU 31 counts the number of pulses of the pulse signal Ps. or not. If it is determined that the electronic expansion valve 23 is not fully opened (step S40: NO), the controller 30 waits. On the other hand, if it is determined that the electronic expansion valve 23 is fully opened (step S40: YES), a notification process (step S50) is executed to notify the user of completion of preparation for refrigerant recovery through the display section (notification section) 3. . The control unit 30 causes the display unit 3 to display, for example, "EEV fully opened" to inform the user that the electronic expansion valve 23 is in the fully opened state. This completes the refrigerant collection preparation process.

When the refrigerant recovery preparation process is completed, that is, after the user is notified by the notification process, the user starts the refrigerant recovery operation using a well-known refrigerant recovery device including a recovery tank, a recovery pump, and the like. At that time, since the electronic expansion valve 23 is fully opened, the refrigerant can be recovered efficiently.

3. Effects of this Embodiment In this embodiment, the electronic expansion valve 23 is always fully opened when the refrigerant is recovered. Therefore, the refrigerant can be efficiently recovered in the ice maker (freezer) 1 provided with the electronic expansion valve 23 .

In addition, the power switch 2 and the operation switch 41 as an instruction unit for generating an instruction signal Sc for instructing recovery of the refrigerant by a user's operation are existing parts provided in the ice making machine 1 in advance regardless of the recovery of the refrigerant. . Therefore, the instruction signal Sc can be generated without adding a new dedicated component for refrigerant recovery. That is, the refrigerant can be efficiently recovered in the ice making machine 1 provided with the electronic expansion valve 23 without adding any special parts.

4. REFERENCE EXAMPLE Next, a reference example relating to the opening/closing control of the electronic expansion valve 23 will be described with reference to FIG.
As a method of controlling the opening of the electronic expansion valve 23, classical PID control is often used, in which the opening of the electronic expansion valve 23 is used as an operation variable so as to keep the degree of superheat ΔT constant. When PID control is used, there is no need to distinguish between increasing and decreasing the manipulated variable in normal PID control in which the controlled variable is positive and negative. However, the degree of superheat ΔT is normally a non-negative controlled variable, and in this case, there is a special circumstance where it is necessary to distinguish between when the manipulated variable is increased and when it is decreased.

As an example of opening/closing control of an electronic expansion valve in consideration of such special circumstances, the technique disclosed in Japanese Patent Application Laid-Open No. 11-83205, for example, is conventionally known. The technology disclosed herein is provided with a discharge pipe temperature sensor that detects the temperature of the discharge pipe of the compressor. , the electronic expansion valve is "slowly opened and fast closed" to solve the problems caused by the above special circumstances.

However, when controlling the opening and closing of the electronic expansion valve based on the degree of superheat ΔT, as described above, the inlet temperature sensor S1 and the outlet temperature sensor S2 are necessary to grasp the degree of superheat ΔT. Being prepared is costly. Therefore, in the reference example, a technique is presented in which the degree of opening of the electronic expansion valve can be "difficult to open and easy to close" without providing a discharge pipe temperature sensor.

That is, in the reference example, as shown in FIG. 5, in PID control (or PI control) in which the opening degree of the electronic expansion valve 23 is used as a manipulated variable so as to keep the degree of superheat ΔT constant, the opening correction gain Gsh is set to An example of changing according to the degree of superheat ΔT is shown.
That is, when the degree of superheat ΔT is as small as 3° C. or less, the electronic expansion valve 23 is wide open, and the flow rate of the refrigerant is large, the opening degree correction gain Gsh is set small. On the other hand, when the degree of superheat ΔT is as large as 10° C. or more, the electronic expansion valve 23 is closed, and the flow rate of the refrigerant is small, the opening degree correction gain Gsh is set large.

Further, when the degree of superheat ΔT is between 3° C. and 10° C., the opening correction gain Gsh is set to increase in proportion to the degree of superheat ΔT, in other words, as the electronic expansion valve 23 closes. . Therefore, when the electronic expansion valve 23 is closed from the open state, the opening degree correction gain Gsh becomes large, so that the electronic expansion valve 23 can be closed quickly (increase the closing speed). On the other hand, when the electronic expansion valve 23 is opened from the closed state, the opening degree correction gain Gsh becomes small, so that it can be opened slowly (reduced opening speed). That is, in the reference example, the opening degree of the electronic expansion valve 23 can be made "difficult to open and easy to close" by setting the opening degree correction gain Gsh according to the degree of superheat ΔT without providing a discharge pipe temperature sensor.

<Other embodiments>
The present invention is not limited to the embodiments described above and illustrated in the drawings. For example, the following embodiments are also included in the technical scope of the present invention. can be implemented with various changes.

(1) In the above embodiment, the instruction section is composed of the power switch 2 and the operation switch 41, and the instruction signal is a signal generated when the power switch is turned on while the operation switch is turned on by the user. , but the indicator and the indicator signal are not limited to this. For example, as the instruction section, a separate switch dedicated to refrigerant recovery that is operated by the user may be separately provided, and the signal of the switch may be used as the instruction signal.

(2) In the above-described embodiment, an example in which the notification unit is configured by the display unit 3 is shown, but the present invention is not limited to this. The notification unit may be, for example, an electronic buzzer or the like that notifies by sound.

DESCRIPTION OF SYMBOLS 1... Ice maker (refrigerating device), 2... Power switch (indication part), 3... Display part (notification part), 20... Refrigerant circuit, 22... Condenser, 23... Electronic expansion valve, 24... Evaporator, 30... Control part 31... CPU (control part) 41... Operation switch (instruction part).

Claims (2)

In a refrigeration system with a refrigerant circuit including an evaporator and a condenser,
an electronic expansion valve that is provided between the condenser and the evaporator and adjusts the flow rate of the refrigerant circulating in the refrigerant circuit according to the degree of opening;
an instruction unit that generates an instruction signal for instructing a transition from a mode in which the refrigerant can circulate in the refrigerant circuit to a refrigerant recovery mode in which the refrigerant circulating in the refrigerant circuit is recovered by a user's operation;
a control unit that controls the degree of opening of the electronic expansion valve;
The control unit
a determination process of determining whether or not the instruction signal has been received from the instruction unit in a standby state in the mode in which the refrigerant can circulate in the refrigerant circuit;
executing full-open processing for fully opening the electronic expansion valve when it is determined that the instruction signal has been received ;
a power switch that turns on and off power supply to the refrigeration system;
and an operation switch for operating the refrigeration device,
The instruction unit is configured by the power switch and the operation switch,
The instruction signal is a signal generated when the power switch is turned on when the power switch is off and the operation switch is turned on by a user . An electronic expansion valve provided between a condenser and an evaporator of a refrigerant circuit and adapted to adjust the flow rate of refrigerant circulating in the refrigerant circuit according to the degree of opening; and a control for controlling the degree of opening of the electronic expansion valve. A refrigerant recovery method for recovering the refrigerant circulating in the refrigerant circuit in a refrigeration system comprising:
The control unit provides an instruction corresponding to a refrigerant recovery instruction from a user for shifting from a mode in which the refrigerant can circulate in the refrigerant circuit to a refrigerant recovery mode in which the refrigerant circulating in the refrigerant circuit is recovered. Upon receiving the signal, executing processing to fully open the electronic expansion valve,
The refrigeration system includes a power switch that turns on and off power supply to the refrigeration system, and an operation switch that operates the refrigeration system,
The instruction signal corresponding to the instruction to recover the refrigerant is generated by turning the power switch from off to on when the operation switch is turned on by a user while the power switch is off. collection method.

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