JPH02230054A - Freezer - Google Patents

Abstract

PURPOSE:To return an operation of a freezer to its safe state before applying a stopping means for a compressor even in case of an occurrence of an abnormal state at a discharged side of the compressor by a method wherein when a discharging pipe temperature exceeds a safe temperature of operation, a degree of opening of an expansion mechanism is metered, and in turn when the temperature reaches a dangerous temperature, the compressor is stopped. CONSTITUTION:A metering of an expansion valve 15 and an emergency stopping of a compressor motor M2 and a condensor fan motor M3 are carried out under an instruction from a microcomputer. A required initial setting of temperature is carried out, a temperature (t) supplied from a compressor discharging pipe temperature sensor 9 is read in and it is discriminated whether the temperature (t) is higher than a safe temperature (t1) or not and if it is lower, the temperature (t) is read. However, if it is higher, it is discriminated whether the temperature (t) reaches a dangerous temperature (t2) or not and if it has not reached the dangerous temperature, a dangerous state is displayed and the expansion valve 15 is metered by a predetermined amount. If the temperature (t) reaches the dangerous temperature (t2), the abnormal state is displayed and then motors M2 and M3 of the freezer 1 are stopped. Even in case that there occurs an abnormal state at a discharging side of the compressor, the freezer can be returned to its safe state before a final emergency means such as a stopping of the compressor is attained while the freezer is being operated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a refrigerator employed in an environmental test device such as a thermostatic chamber.

[Conventional technology]

Protection devices for refrigerators used in environmental test equipment such as constant temperature and humidity chambers include high/low pressure switches, overcurrent protection devices, and determination devices based on discharge pipe temperature. When an abnormality is detected, the compressor is immediately stopped to protect the refrigerator.

[Problem to be solved by the invention]

However, when the compressor was stopped, the atmosphere inside the test tank was greatly disturbed, causing problems such as the need to redo the test and the samples in the test chamber being scratched.

Therefore, even if an abnormality occurs on the discharge side of the compressor, unless it is dangerous to continue operating the compressor, the present invention allows the compressor to remain in operation before taking the final emergency measure of stopping the compressor. The purpose of the present invention is to provide a refrigerator that can return the refrigerator to a safe state.

[Means for Solving the Problems] According to the above object, the present invention includes a temperature detection means for detecting the temperature of the compressor discharge pipe, and also includes a variable opening expansion mechanism as the expansion mechanism, and further includes a temperature detection means for detecting the temperature of the compressor discharge pipe. The compressor is provided with means for reducing the opening degree of the expansion mechanism when the detected temperature of the discharge pipe exceeds a predetermined safe temperature for use, and means for stopping the compressor when the temperature of the discharge pipe reaches a predetermined dangerous temperature. The present invention provides a refrigerator featuring the following features.

[Function] According to the refrigerator of the present invention, when the compressor discharge pipe temperature exceeds the safe operating temperature, the opening degree of the expansion mechanism is changed while the refrigerator is operating, unless it is still dangerous to continue operating the refrigerator. The refrigerator is protected by throttling, and when the discharge pipe temperature reaches a critical temperature, the compressor is stopped.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic explanatory diagram of a thermostatic chamber to which an embodiment refrigerator is applied.

The constant temperature constant temperature chamber 10 shown in FIG. 1 has a test area 102 in which a sample is housed in a constant temperature chamber 101, and an air conditioned room 104 is provided behind the area with a partition wall 103 interposed therebetween. The air conditioned room is equipped with a cooler 11 and an air circulation fan 12 above it.

An electric heater 2 is provided between the cooler 11 and the fan 12, and an evaporative humidifier 30 of a type that heats water with a humidifying electric heater 3 is provided below the cooler. ing. Air is circulated in the eight directions indicated by the arrows by the action of the fan 12. Cooler l1 is a constituent member of refrigerator l. The refrigerator 1 includes a compressor 13, a condenser 14, and a variable-opening electronic expansion valve 15 for the cooler 11, which are arranged outside the air-conditioned room of the cooler 11.

The valve 15 is of a type in which when a shaft (not shown) is rotated, the valve body moves and the valve opening degree changes.

The shaft is driven by a stepping motor 41, and a pulse output generator 42 is connected to the motor 41. This generator 42 operates based on instructions from a microcomputer M (hereinafter referred to as "microcomputer M").

A current supply circuit 21 is connected to the heater 2, and a current supply circuit 3l is connected to the humidifying heater 3. These circuits 21 and 31 operate based on instructions from the microcomputer M.

The motor M1 that drives the fan 12 is connected to the compressor motor M2 and the fan 14 for the condenser 14 via the drive circuit C■.
The first drive motor M3 is connected to each microcomputer M via a drive circuit C2.

Inside the tank 101, a dry bulb temperature detector 5 and a wet bulb temperature detector 6 are provided near the outlet of the air conditioned room 104.
The outputs of these detectors are input to the microcomputer M. Also,
A temperature detector 7 for measuring the ambient temperature is arranged in the airflow flowing into the condenser 14 in the refrigerator 1, and a temperature signal from the detector is also inputted to the microcomputer M.

Further, the discharge pipe of the compressor 1 is provided with a temperature detector 9 for detecting abnormalities in the refrigerator, and a signal from this detector is also input to the microcomputer M.

An operation board 8 including a numeric keypad and the like is connected to the microcomputer M, and the board 8 allows selection of temperature operation, temperature/humidity operation, or gradient operation mode, and in the case of temperature operation, the target temperature, In the case of temperature/humidity operation, the temperature change gradient can be set by setting the target temperature and humidity, and in the case of gradient operation, the temperature at the start of the gradient operation, the temperature at the end of the gradient operation, and the time required therebetween. Furthermore, the order of various operations can be input as appropriate. That is, for example, at 50°C and 60% RH for 3 hours, then lowering from 50°C to 20°C at 60% RH in 2 hours, then at 20°C.
The operating order can be set such as 3 hours at °C and 60% RH.

The board 8 is further provided with instruction keys for starting or stopping the fan motor M1, the compressor motor M2, the fan motor M3, etc. in order to start the operation of the constant temperature constant temperature chamber IO.

According to the constant temperature incubator shown in FIG. ), the temperature in the test area 102 is monitored by the dry bulb temperature detector 5, and the output of the heater 2 is controlled based on instructions from the microcomputer M.

Also, in the case of gradient operation, the output of the heater 2 is controlled according to the temperature change gradient instructed on the board 8.

In the case of temperature and humidity operation, that is, operation in which the inside of the tank 101, more precisely, the test area 102, is maintained at the temperature and humidity (target temperature and humidity) set on the board 8, the temperature and humidity inside the test area 102 are measured by temperature detection. The outputs of the heater 2 and the humidifying heater 3 are controlled based on instructions from the microcomputer M while being monitored by the microcontrollers 5 and 6. In either case, an instruction key on the operation board 8 is used to instruct the fan 12 and the refrigerator 1 to start operating.

Further, in any operation, the valve 15 is opened and closed as necessary based on instructions from the microcomputer M, as described later.

The main routine controlled by the microcomputer M is as shown in FIG.

First, when the program starts, initial settings for initializing the microcomputer M, etc. are performed in step Sa. Next, in step sb, a man-machine interface process, that is, a process of writing information inputted via the board 8 into the memory, is performed, and then, in step Sc, a control process is performed, and the process returns to step Sa.

When there is a timer interrupt at predetermined time intervals from a timer IC (not shown) (step Sd), timer management processing is first performed in step Se, and then step S
The output of the heater is controlled in f, the expansion valve opening is controlled in step Sg, the operation of the refrigerator (especially motors M2 and M3) is controlled in step sh, and the process returns.

The timer management processing routine in step Se is as shown in FIG. 3. First, in step Se1, the counter is updated, and in step Se2, it is determined whether or not a predetermined time S has been reached, and if it has not yet, the process returns.
If the predetermined time has been reached, the timer flag is set to "I" in step Se3, and the timer counter is reset in step Se4.

The control processing of the subroutine Sc shown in the main routine is as shown in FIG.

First, in step Scl, the timer flag is set to '1'.
'° is determined, and if it is '1°, step Sc2
The counter C is updated at step Sc3, and then C=1 at step Sc3.
If so, the process advances to step Sc4 and temperature control calculation processing is performed. In step SC3, if (,f-1), it is determined in step Sc5 whether C=2 or not, and if C=2, the process proceeds to step Sc6, where humidity control calculation processing is performed, and then step Sc7 The counter is reset in Step S04 and (Sc6, Sc7), after which the process proceeds to Step Sc8, where the expansion valve opening degree processing is performed, and the timer flag is set to "0" in Step Sc9.
Set to ° and return to the main routine. If the timer flag is not 11 1 11 in step Scl, the process immediately returns to the main routine.

Necessary opening/closing of the expansion valve is executed in the expansion valve opening degree processing in step Sc8 in this control processing routine and in the expansion valve opening degree control in step Sg in the interrupt routine Sd based on this processing.

Therefore, the outline of the expansion valve opening degree processing routine Sc8 is shown in FIG.
This will be explained based on the flowchart shown in FIG.

First, in step S1, it is read whether the refrigerator 1 is on or off, and in step S2, an alarm check is performed. This alarm check is for detecting an abnormality in the refrigerator 1, and in this example, a temperature signal from the temperature detector 9 that measures the discharge pipe temperature of the compressor 13 is read.

Next, in step S3, the presence or absence of an alarm is determined. In this example, this determination is to determine whether the discharge pipe temperature L is higher than a predetermined safe temperature ti, and rYES.
If so, the discharge pipe temperature is abnormal, and the process proceeds to step S4.

In step S4, it is determined whether the temperature t has reached a predetermined dangerous temperature.

If t2 has been reached, it is immediately decided to stop the compressor in step S5, and step s in the timer interrupt routine Sd is executed.
Stop the refrigeration machinery (motors M2 and M3) at h. However, if the discharge pipe temperature t is smaller than t2, step S6
Then, it is decided to close the expansion valve 15 by a predetermined amount. Based on this determination, the expansion valve is closed in step Sg of the timer interrupt routine Sd. This operation of closing the expansion valve is repeated until the discharge pipe temperature L becomes equal to or less than the predetermined safety limit temperature.

Now, if it is determined in step S3 that the discharge pipe temperature L is a safe temperature, it is determined in step S7 whether or not the refrigerator is on, and if it is off, it is determined in step S8 whether or not the zero reset has been completed. If this zero reset has been completed, the process returns immediately, but if it has not yet been done, the process returns to zero in step S9. This zero reset issues a command to completely close the expansion valve 15 when the refrigerator is not in operation. Based on this zero reset, the expansion valve is closed by step Sg in the interrupt routine Sd.

If the refrigerator is on in step S7, step SIO
Then, it is determined whether the next operation set on the board 8 is a slope operation. If the next operation is not a gradient operation, in step 311 the test area 1 of the constant temperature incubator is
It is determined whether the state at 02 is stable. In other words, if it is temperature operation, check whether the target temperature set on the board 8 is stable within the range of error ±a''C.
In the case of temperature/humidity operation, it is determined whether the set target temperature is stable within the range of error ±a″C and the set target humidity is stable within the range of error ±b%RH. Alternatively, it is determined whether or not slope operation is currently being performed.Step S1
If the result of these determinations in step 1 is rNOJ, the process advances to step S12 shown in FIG.

In steps S12 to 3151, the maximum allowable opening degree Mmax of the expansion valve 15 in the refrigerator 1 under the current ambient temperature RT and the current tank internal temperature T is determined.

There are various ways to determine Mmax, but here it is determined from the ambient temperature RT and the tank internal temperature T. Ambient temperature R
T is determined by the temperature detector 7 shown in FIG. 1, and the tank internal temperature T is determined by the temperature detector 5 shown in FIG. In step S13, if the ambient temperature RT is determined from the maximum permissible expansion valve opening obtained in advance by varying the tank internal temperature T and the ambient temperature RT, 2X that can calculate the maximum allowable distance Mmax
seek. In this example, this relational expression X is obtained as a linear equation.

That is, Mmax=aXT+b (primary 2X),
a=f (RT), b=f (RT).

After obtaining the relational expression X in this way, it is determined in step S1.1 whether the temperature should be raised or lowered toward the set temperature (target temperature).

In the case of temperature reduction processing, the process proceeds to step S151, where the current temperature T in the tank is substituted for 2X, and the maximum permissible opening degree MmaX of the expansion valve under the temperature T is calculated.

Next, in step S16, a difference P2 between the maximum allowable opening degree Mmax of the expansion valve and the current opening degree N of the expansion valve is determined.

Thereafter, it is determined whether to open or close the expansion valve depending on the positive or negative sign of P2 determined previously (step S17).

Next, in step 318, the minimum valve opening degree Mmin that is allowable in the temperature reduction process is selected and determined depending on the type of operation, that is, temperature operation or temperature/humidity operation. Such a minimum allowable opening degree is selected from among the minimum allowable opening degrees that are predetermined according to the type of operation and stored in the memory.

In addition, Mmin in the temperature reduction process is determined by ensuring that the oil flowing together with the refrigerant in the refrigeration circuit does not clog the valve part, that the pressure on the low pressure side of the circuit does not become abnormally low, and that even though the amount of refrigerant circulated is small, This is determined by taking into consideration factors such as a constant flow rate without fluctuation.

After determining the minimum allowable opening degree Mmin in this way, it is determined in step 319 whether the current valve opening degree N is between Mmax and Mmin, and if it is, step S20
An opening command with the valve operation amount Pm=IP2 is output.

If the determination in step S19 is "NO", it is determined in step 321 whether or not the current valve opening degree N is greater than Mmax, and if it is, a command to close the valve up to Mmax is output, and if not, that is, N When <Mmin, a command to open the valve up to Mmin is output in step 323.

In this way, Mmin<N<Mmax. ．． Mma
The reason for determining x<N, N<Mmin is that Mmax<N or N<Mm has already been determined in the previous expansion valve opening operation.
This is because there are cases where it is in.

The commands issued in each of steps S20, S22 and S23 are executed in the expansion valve control process of step Sg in the timer interrupt routine Sd shown in FIG.

In this way, temperature drop control in a constant temperature and humidity chamber lO
Safely, taking into account the maximum allowable opening degree MmaX of the expansion valve 15 under the current ambient temperature RT and the current tank internal temperature T.
Further, the opening degree of the expansion valve 15 can be controlled so as to approach the set temperature (target temperature) by also taking into account the predetermined minimum allowable opening degree Mmin of the expansion valve.

If it is determined in step 314 that the temperature increase process is to be performed, the process proceeds to step S152, where the target in-tank temperature T is applied to the formula X obtained in the previous step S13. and temperature T. Find the maximum allowable opening degree Mtmax.

Next, in step 324, the current tank temperature T and the tank set temperature (
The current maximum permissible expansion valve opening degree Mmax is determined based on the difference ΔT between the target temperature) To, and then in step S25, the difference P3 between this Mmax and the current expansion valve opening degree N is determined. How to obtain Mmax here will be described later.

In step 326, it is determined whether the valve is open or closed depending on the positive or negative sign of P3.

Thereafter, the process proceeds to step S18 in the same way as in the temperature drop control described earlier, and here the minimum allowable opening suitable for the temperature rise control operation is selected from among the minimum allowable valve openings Mmin predetermined according to the type of operation. Determine the degree Mmin.

After that, the operation fJPm=lP3 is performed in step S20 depending on the magnitude relationship between the current opening degree N and Mmin and Mmax.
1, output a command to open or close the valve, or output a command to close the valve up to Mmax in step S22,
In step S23, a command to open the valves up to Mmini is output.

This command is executed in the expansion valve control at step Sg in the timer interrupt routine Sd.

In addition, the minimum allowable opening degree Mm of the valve in temperature rise control
in is also determined from the same viewpoint as the minimum allowable valve opening degree in the temperature drop control.

Current temperature T in the tank and target temperature T in the tank. The current maximum allowable valve opening degree Mmax that is allowed under the difference ΔT between , various ways of determining are possible, but here the current ambient temperature RT and the target temperature T. It is later determined as a function of the maximum allowable opening degree Mtmax and the temperature difference ΔT. That is, here, ΔT = T - T. k is a predetermined correction coefficient depending on whether the control takes only temperature into consideration or the humidity is also taken into consideration; temperature setting range: for example, -10 to 50°C.

Temperature increase system like this? In ffl operation, the maximum allowable opening Mmax of the expansion valve that can be opened at present is determined by taking into account the difference ΔT between the current tank temperature and the target tank temperature.
The expansion valve opening is suddenly set to the target tank temperature T. If the maximum allowable opening degree Mtmax is set to , the adverse effect of slowing down the rate of temperature rise in the tank can be prevented. When the target temperature is reached, there will be a large allowable heat generation load. Moreover,
When opening and closing the expansion valve, from step 319 onward, the current opening degree N, maximum allowable opening degree Mmax, and minimum allowable opening degree Mmin are determined.
Since the magnitude relationship between the

There are 10 people in ``-'' and ``f''.Now, the process returns to step 310 again. If it is determined in step S10 (FIG. 5) that the next setting is gradient operation, the process proceeds to step S27, where it is determined whether or not it is upward gradient operation. In the case of upward slope operation, a predetermined fixed minimum allowable expansion valve opening degree Mmin is determined in step S271.

During this time, the degree %min is determined by a suitable heater at any temperature rise, so that there is a smooth transition from the current operation to the next slope operation, i.e., it is possible to enter immediately into a stable upward slope operation without disturbances. This is the opening degree that has been experimentally confirmed to produce output.

If the next setting is descending gradient operation, the process advances to step S28, where the temperature TS at the start of operation and the temperature T at the end of operation are set.
The slope is calculated from E and the operation control time MN using the following formula.

Next, in step S29, the minimum allowable expansion valve opening degree Mmtn=f (gradient) suitable for this gradient is calculated.

It is desirable to define this formula so that the slope can be selected from as wide a range as possible, and various possibilities can be considered, but here, based on experiments, we have determined that there is no abnormality in the refrigerant circuit and a smooth transition to the next set descending slope operation is possible. stipulated in

That is, in this example, Mmin=MpX gradient 10Mq. Here, Mp and Mq are constants, and there is a relationship of Mp>Mq.

In this way, in step 327 or S29, the expansion valve minimum allowable opening degree Mmin when the next operation is gradient operation is determined.
After determining, the process advances to step S30.

Here, the operation amount P1 corresponding to the current operation type is selected and determined from among the expansion valve operation amounts that are predetermined according to the operation type.

Next, in step S31, the average value of the heat output is determined. Here, the heater refers to heater 2 when temperature operation is currently in progress, and heater 2 when temperature and humidity operation is currently in progress.
and the humidifying heater 3.

Calculation of this average heater output value is based on a plurality of values measured and stored in the temperature processing subroutine (step SC4) and humidity processing subroutine (step Sc6) in the control processing routine Sc shown in FIG. 4 before reaching step S31. Calculated based on the output value.

After calculating the heater output average value in this way, step S
32, the upper limit HU and lower limit HD of the heater output according to the current type of operation, or the upper and lower limit H of the heater output.
Select and determine the upper limit hu and lower limit hd of U, HD, and humidifying heater output.

Note that these upper and lower limits are predetermined in accordance with the type of operation and are stored in the memory of the microcomputer M so that the heater output can be saved as much as possible while ensuring smooth control.

Next, in steps S33 to S336, it is determined whether the heater output is being controlled between the upper and lower limits of the heater output appropriate for the current type of operation, that is, within an appropriate heater output control range, and the determination is made as follows. '', it is decided to manipulate the opening degree of the expansion valve so that the output is controlled within such an appropriate range.

To explain this in more detail, if the current temperature operation or gradient operation without taking humidity into consideration, step S33
It is determined whether the heater output average value HA is larger than the heater upper limit HU, and if it is larger, it is determined to close the expansion valve with the operation amount P (step S331). If it is smaller, it is determined whether or not the heater output average value HA is between the upper limit HU and lower limit HD of the heater output, and if it is, the valve opening degree is not adjusted in step S35. is determined, and “No”, that is, the average value HA
If P is smaller than the lower limit HD, in step S36, the expansion valve opening operation based on the manipulated variable P is determined.

If the current operation is a temperature/humidity operation or a gradient operation that takes humidity into consideration, in step S33, the average heater output value HA is larger than the upper limit HU of the humidifying heater output, and the average humidifying heater output value ha is the upper limit of the humidifying heater output. Determine whether it is larger than hu, and if rYESJ, step S
If the result is NOJ, the process advances to step S34. Then, in step 334, the average heater output value HA is between the upper limit HU and the lower limit HD of the heater output, and the average humidifying heater output value ha is the upper limit h of the humidifying heater output.
It is determined whether the value is between u and the lower limit hdO. rY
If Es, the process advances to step S35, and if "NO", the process advances to step S36.

After determining the opening/closing of the expansion valve according to the operation amount P1 in this way, in steps S37 to 339, the sixth
The maximum allowable opening degree M a x of the expansion valve under the current ambient temperature RT and current tank temperature T is determined using the same method as in steps 312 to S15l shown in the figure, and then the process proceeds to steps 319 and subsequent steps already described. move on.

Note that when it is determined in step SIO shown in FIG. 5 that the next setting is gradient operation, the process proceeds to step S27, and then proceeds to step S19 via step S39. This is the determined Mmin or the Mmin calculated in step 329, and the manipulated variable Pm in step 320 is the manipulated variable Pl determined in step S30.

If it is determined in step 311 (FIG. 5) that the temperature operation or temperature/humidity operation is stable, or that the slope operation is currently in progress, the process proceeds to step Sill (FIG. 8), where the type of operation is determined. The minimum permissible opening degree Mmin of the expansion valve is determined according to the following, and the process then proceeds to the already explained step S30 and subsequent steps. In this way, even when temperature operation or temperature/humidity operation is in a stable state, or during gradient operation, the heater output is optimized depending on the type of operation, and smooth temperature or temperature/humidity control is performed. Try to save money.

Note that when proceeding from step S11 to step S19 via steps Sill to 339, step 319
The expansion valve minimum allowable opening degree Mmin thereafter is Mmin determined in the previous step Sill.

In addition, in the procedure explained above, the expansion valve opening degrees Mmax, Mtmax, and Mmin are actually the opening degrees of a certain state of the expansion valve, for example, based on the completely closed state, and the opening degrees of Mmax, MLmax, and XMmin from there. It is treated as the number of pulses required to reach the target. Further, the expansion valve operation amount Pm (PI, P2, P3) is also treated as a pulse number.

Note that the present invention is not limited to the above embodiments,
Other embodiments are also possible.

For example, if we consider only the control of stopping the refrigerator or throttling the expansion valve when the temperature of the compressor discharge pipe of the refrigerator L is abnormal, as illustrated in FIG. It may also be executed by a separate microcomputer. In this case, the throttle of the expansion valve 15, the compressor motor M
The emergency stop of condenser fan motor M3 and condenser fan motor M3 is performed by instructions from the microcomputer. In the flowchart of FIG. 10, necessary initial settings are performed in step #l, temperature L provided from the compressor discharge pipe temperature detector 9 is read in step #2, and temperature is also lower than the safe temperature t1 in step #3. It is determined whether the temperature L is greater than the critical temperature t2, and if it is small, the process returns to step #2, but if it is large, the process proceeds to step #4. A danger display is displayed in step #5, and the expansion valve 15 is throttled by a predetermined amount in step #6. If the temperature t has reached the dangerous temperature t2 in step #4, an abnormality is displayed in step #7, and the refrigerator 1 (motors M2, M3) is stopped in step #8.

Incidentally, the danger display means and the abnormality display means are also connected to the microcomputer (not shown).

[Effects of the Invention] According to the present invention, even if an abnormality occurs on the discharge side of the compressor, unless it is dangerous to continue operating the refrigerator, the operation of the refrigerator is stopped before taking the final emergency measure of stopping the compressor. It is possible to provide a refrigerator that can be returned to a safe state while in operation.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of a thermostatic chamber to which a refrigerator according to an embodiment of the present invention is applied. FIG. 2 is a flowchart showing the main routine of the operation of the microcomputer M shown in FIG. I, FIG. 3 is a flowchart showing the timer management routine, and FIG. 4 is a flowchart showing the control processing routine. 5 to 9 are flowcharts showing the expansion valve processing subroutine shown in FIG. 4. FIG. 10 is a flowchart showing the operation of the expansion valve and refrigerator control microcomputer in another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Refrigerator, 2... Heater, 3... Humidification heater, 15... Electronic expansion valve, 5... Dry bulb temperature detector, 6... Wet bulb temperature detector, 7 ... Ambient temperature detector, 9... Compressor discharge pipe temperature detector, M... Microcomputer, 8... Operation board, 10... Constant temperature and humidity chamber, 01... Tank, 02 ...Tankouchi child strike area. Tabai Espec Co., Ltd. Figure Figure

Claims (1)

[Claims] (1) Equipped with a temperature detection means for detecting the temperature of the compressor discharge pipe and a variable opening expansion mechanism as an expansion mechanism,
Furthermore, means for reducing the opening degree of the expansion mechanism when the temperature of the discharge pipe detected by the temperature detection means exceeds a predetermined safe use temperature; A refrigerator characterized in that it is equipped with a means for stopping.