JPH052912B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for controlling the operation of a refrigerator, and more specifically, a first cooler using brine as a cooling medium, and a first cooler using a refrigerant from a refrigeration system as a cooling medium. In a constant temperature/humidity refrigerator which is equipped with a second cooler and configured so that the interior of the refrigerator is mainly cooled by the first cooler, the first cooler is controlled by controlling the operation of the refrigerator.
The present invention relates to means for effectively controlling the temperature rise inside the refrigerator during the defrosting period of the cooler.

Conventional technology and its problems When considering the operation control of ordinary refrigerators that use refrigerants such as fluorocarbon gas, when the temperature inside the refrigerator rises to the upper limit temperature set by the thermostat, the operation of the refrigeration system is restarted and the operation of the refrigerator is resumed. When the internal temperature drops to the lower limit set temperature, the operation of the refrigeration system is stopped. In this case, the smaller the difference between the upper limit set temperature and the lower limit set temperature, the better, but if the difference is set too small, the refrigeration system compressor will This results in repeated and troublesome starting and stopping, which can cause startup failures and other malfunctions. Furthermore, since the starting current is large, the amount of power consumed also increases, resulting in an uneconomical operating cost. This is dealt with by setting a relatively large temperature difference (approximately 5 to 6 degrees Celsius) between the upper and lower temperature settings in the refrigerator. Since the quality of the product changes between the upper and lower set temperatures, there was a problem in maintaining the quality.

In addition, the moisture inside the refrigerator condenses and freezes on the surface of the cooler.
Although the frost grows in layers, this frost reduces the efficiency of heat exchange between the cooler and the air inside the refrigerator, so regular defrosting operations are required. In this defrosting process, hot gas drawn out from the refrigeration system is passed through the cooler, or a heater provided close to the cooler is heated with electricity to melt the frost that has adhered to the cooler. However, during this defrosting operation, the temperature inside the refrigerator gradually rises (approximately 10 to 13 degrees Celsius) due to heat radiated from the cooler heated by the hot gas, etc., and heat entering from the outside. For this reason, the freshness and quality of foodstuffs stored in the refrigerator further rapidly deteriorate.

Therefore, in order to store fresh food frozen for a long period of time without deterioration of quality, it is generally necessary to keep temperature changes inside the refrigerator to a minimum and also to manage the food to prevent moisture evaporation. A type of refrigerator that uses brine (antifreeze) as a cooling medium is known. In other words, brine can be cooled to below 0°C and has a large heat capacity, so the temperature inside the refrigerator can be lowered to 0°C.
There is an advantage in that temperature changes can be suppressed by setting the temperature below .degree. C., but conversely, the moisture inside the refrigerator condenses on the walls, causing frost to grow in layers, resulting in poor cooling of the interior over time. To remove this frost, it is necessary to raise the temperature of the brine or heat it with a heater etc. to melt the frost, but in any case, the disadvantage of increasing the temperature inside the refrigerator during defrosting is avoided. I can't.

Purpose of the Invention The present invention has been proposed in view of the above-mentioned drawbacks inherent in ordinary refrigerators that use refrigerants such as fluorocarbon gas and refrigerators that use brine as a refrigerant, and to suitably solve these problems. A method for controlling the operation of a refrigerator that prevents the internal temperature from rising during defrosting operation and deteriorating the quality of food, and also eliminates failure to start the refrigeration system, motor overload damage, and other wasteful power consumption. The purpose is to provide

Means for Solving the Problems In order to overcome the above-mentioned problems and suitably achieve the above-mentioned objects, a refrigerator operation control method according to the present invention provides a method for controlling the operation of a refrigerator defined inside a box for cooling and storing foodstuffs. a refrigeration system comprising a refrigerant compressor, a condenser, etc.; a brine tank for storing brine; a second cooler disposed in the storage, to which refrigerant from the refrigeration system is supplied by opening a second solenoid valve that is always closed; and the brine tank. and a third cooler disposed inside the refrigerator, to which refrigerant from the refrigeration device is supplied via a first solenoid valve that is normally open, the refrigerator comprising: During the frost period, the operation of the refrigeration system is continued, the supply of brine in the brine tank to the first cooler is stopped, and the second solenoid valve and the first solenoid valve are alternately switched. Accordingly, while the second solenoid valve is open, the second solenoid valve is opened.
The cooler is operated for cooling to suppress the rise in temperature inside the refrigerator, and while the first solenoid valve is open, the third cooler is operated for cooling to maintain the brine in the brine tank in a supercooled state. It is characterized by being made to do.

Embodiment Next, the method for controlling the operation of a refrigerator according to the present invention will be described below with reference to the accompanying drawings by exemplifying a brine cooling type constant temperature and high humidity refrigerator that can suitably implement the method.

(About the general structure of the refrigerator) FIGS. 1 to 3 show the external appearance and internal structure of a constant temperature and high humidity refrigerator in which the operation control method according to the present invention is suitably implemented. This refrigerator is divided into a box body 1 and a cooling unit part 2, and a top plate 3 is commonly disposed on the upper part. A storage compartment 1a is defined inside the box body 1 for cooling and storing foodstuffs, and this storage compartment 1a
The opening is opened and closed by doors 4, 4. Further, inside the storage 1a, a shelf (not shown) on which stored items are placed is horizontally provided in a removable manner.

The cooling unit section 2 is removably covered by a cover 5, and when this cover 5 is removed, various members constituting the refrigeration device 6 and the brine cooling unit section 9 are exposed, as shown in FIG. This refrigeration system 6 is composed of a compressor 60, a solenoid valve, a fan motor, and a condenser 7, etc. Above the refrigeration system, there is a brine cooling unit section 9 including a brine tank 8, an internal temperature controller 10, and a thermometer 11. , an electrical equipment box 13 having an abnormality warning lamp 12 and the like is provided.

FIG. 3 shows a cross section of a main part of the constant temperature/humidity refrigerator according to this embodiment, and a heat insulating material 16 is filled between the outer box 14 and the inner box 15 that constitute the box body 1. A first cooler 17 to which brine as a cooling medium is circulated and supplied is fixedly arranged on the right side of the inside of the storage defined in the inner box 15 . As this first cooler 17, a fin-and-tube type is preferably adopted, but it may also be a plate type. Furthermore, as shown in the figure, a cooling duct 18 is disposed that is open at the bottom and sealed at the top, and covers the first cooler 17 in a non-contact manner.

Note that an opening 19 is formed in the cooling duct 18,
The refrigerator air sucked from below the cooling duct 18 is cooled by the fan motor FM ₁ 20 for circulating cold air disposed in the opening 19 by exchanging heat with the first cooler 17. It is blown out from the refrigerator and circulated as shown by the solid arrow in FIG. 6 to cool the entire interior of the refrigerator. Further, a defrosting thermometer Th ₁ for detecting the end of defrosting and a heater H ₁ for promoting defrosting are arranged near the first cooler 17, and further below the first cooler 17, a dew pan 21 is provided. The water droplets dripping from the cooler 17 during defrosting are collected and discharged outside the refrigerator.

Further, a second cooler 22 to which liquefied refrigerant from the refrigeration device 6 is circulated and supplied is fixedly arranged on the left side inside the storage. A cooling duct 23 that is open at the bottom and sealed at the top is disposed inside the refrigerator, and covers the second cooler 22 in a non-contact manner.
An opening 24 is formed in this cooling duct 23, and a fan motor FM ₂ 25 disposed in this opening 24 circulates the air inside the refrigerator as shown by the broken line arrow in FIG. 6 to cool the entire inside of the refrigerator. It's becoming like that. Near the second cooler 22, there is a defrost thermometer Th ₂ for detecting the end of defrosting and a heater for promoting defrosting.
H ₂ is provided, and a dew pan 26 is provided below the cooler 22 to discharge water droplets that drip during defrosting to the outside of the refrigerator. In FIG. 6, reference numeral 70 indicates a temperature-sensing section of the internal refrigerator thermometer _Th3 , which is disposed at a suitable location within the refrigerator.

(Regarding the Brine Cooling Unit Section) Details of the brine cooling unit section 9 are shown in FIGS. 4 and 5. This brine cooling unit section 9 functions to cool the brine with the refrigerant from the refrigeration device 6 and to circulately supply the brine to the first cooler 17 as a cooling medium. Brine tank 8 disposed in this unit section 9
is configured as a box-shaped container in which a heat insulating material 32 is filled between an outer box 30 and an inner box 31, and the upper opening is a lid in which a heat insulating material 36 is interposed between an upper lid 34 and an inner lid 35. It is removably attached to the body 33. Each end edge of the upper lid 34 is bent at right angles, and is fitted into the outer box 30 of the tank 8 to form the upper end 3 of the tank 8.
7 and the inner lid 35 are in close contact with each other. Note that the end portion of the upper lid 34 is fixed to the tank outer box 30 via bolts 38.

One end of a suction pipe 39 is communicated with the lower side wall of the inner box 31 in the tank 8, with its opening facing into the tank, and the other end is connected to a brine circulation pump 40.
It is connected to the suction pipe 41 of. A discharge pipe 42 communicating with the discharge side of this pump communicates with a supply pipe 67 of the first cooler 17. Further, a discharge pipe 43 which is bent into a key shape and opens downward is provided at the upper part of the side wall of the inner box 31 (above the suction pipe 39), and the other end of this discharge pipe 43 is connected to a return pipe 44 made of a hose.
It is connected to. The return pipe 44 is connected to the return pipe 68 of the first cooler 17 . Note that the discharge pipe 4
2, 43 and the return pipe 44 are covered with a heat insulating hose 45.

An L-shaped support plate 4 is attached to the bottom 31a of the tank 8.
8 is fixed via bolts 49, and this support plate 4
8, a third cooler 47 (connected to the refrigeration device 6)
is arranged in a coiled manner to cool the brine 46 stored in the tank (7) to a required temperature. Note that the bolt penetration portion of the bottom portion 31a is sealed by a screw receiver 50 adhered to the back surface of the bottom portion to prevent external leakage of brine.

A brine detection tank 51 having a function of detecting the presence or absence of brine circulation is fixed to the side wall 31b of the tank inner box 31 via bolts 52, and is located at an intermediate position within the tank 8 (above a predetermined storage level of brine). is coming. This brine detection tank 51
As shown in FIG. 5, it is constructed as a box with an open top surface, and a drain hole 53 is provided at the bottom 51a. The liquid drain hole 53 is connected to the discharge pipe 4
The hole diameter is set to such an extent that only a very small amount of brine can pass therethrough compared to the circulating amount of brine flowing down from No. 3 into the detection tank 51. Therefore, the discharge pipe 43
A part of the brine supplied from the drain hole 53
However, most of the brine is stored in the detection tank 51.
The brine eventually overflows from the upper edge 51c of the side wall of the detection tank 51 and flows down into the brine tank 8.

Further, an L-shaped mounting plate 54 is fixed to the side wall 51b of the brine detection tank 51, and a float switch 55 is mounted on the plate surface extending from the tank opening. This float switch 55 is equipped with a float 55a, and when the brine in the detection tank 51 decreases, the float 55a descends and closes the switch.
When 0FF is activated and the detection tank 51 is filled with brine and overflows, the float 55a rises and the switch is turned ON. Note that instead of providing a float switch, an electrode type switch, pressure type switch, or other mechanical type switch may be used.

It is convenient if the brine tank 8 is provided with a liquid level gauge 101 based on the principle of a communicating tube, so that the brine liquid level in the tank 8 can be visually checked from the outside. The liquid level gauge 101 is, for example, a synthetic resin tube (hose) that is transparent and can be bent without deteriorating under low temperature conditions.
is preferably used, and the lower end of this tube is connected to the side surface of the tank 8 in communication. The tube stands upright outside the tank and is fixedly supported by a fixing piece 102. Further, a cap 104 having a through hole is attached to the upper end of the liquid level gauge 101. Also the first
As shown in FIG.
A rectangular viewing window 100 is provided in the cover 5 so that the liquid level gauge 101 can be seen when the cover 5 is attached. With the liquid level gauge 101, it is possible to easily check from the outside whether there is brine in the tank 8 or whether a predetermined amount of brine is stored. Furthermore, the liquid level gauge 101 can also be used for draining brine in the tank 8 by removing it from the tank 8.

(Regarding the Refrigeration Circuit and the Brine Circulation Circuit) FIG. 6 is a schematic system diagram showing each pipe system of the refrigerant-based refrigeration circuit and the brine circulation circuit. In the figure, refrigerant gas compressed by a compressor 60 (CM) is liquefied in a condenser 7, dehumidified in a dryer 62, and then connected to a pipe on the first solenoid valve _V1 side and a second solenoid valve _V2.
It is branched into a side pipe. The liquefied refrigerant that has passed through the first electromagnetic valve V ₁ is depressurized by the capillary reach tube 63 and then is removed from the third solenoid valve V 1 disposed in the brine tank 8 .
It evaporates in a cooler 47 and exchanges heat with the brine to cool the brine. The evaporated refrigerant returns to the compressor 60 via the suction pipe 64.

Furthermore, the liquefied refrigerant that has passed through the second solenoid valve _V2 is depressurized by the capillary reach tube 63, evaporates in the second cooler 22, and exchanges heat with the air inside the refrigerator.
Cool the inside of the refrigerator. The evaporated refrigerant is transferred to the suction pipe 6
6 and returns to the compressor 60. In this case, a gas-liquid separator (accumulator) may be provided on the outlet side of the second cooler 22 and the third cooler 47, and check valves may be provided in the suction pipes 64 and 66, respectively. Good too. Note that the code in Figure 6 is FM ₃ (61)
shows a fan motor for the condenser 7.

Next, to explain the brine circulation circuit, the brine 46 stored in the brine tank 8 is cooled to a required temperature by a third cooler 47 connected to the refrigeration device, and the brine 46 is cooled to a required temperature by a suction pipe 39 led out from the tank 8. After being sucked out by the circulation pump 40 through the
is supplied to the cooler 17. and the first cooler 1
After cooling the pipe 7 and exchanging heat with the air inside the refrigerator, the return pipe 6
8 through a key-shaped discharge pipe 43 and returned into the brine detection tank 51.

As described above, some of the brine returned to the detection tank 51 flows down from the return hole 53, and the rest overflows from the upper edge 51c of the side wall of the detection tank 51 and is stored in the brine tank 8. When the liquid level in the detection tank 51 rises, the contact of the float switch 55 is turned on.

(Regarding electrical control circuit system) FIG. 7 shows an example of an electrical control circuit for a constant temperature and humidity refrigeration device. In this circuit diagram,
R phase and T phase are control power bus, F is fuse, L ₁
is the power lamp, CM is the compressor, FM ₃ is the condenser fan motor, T is the timer, TM is the cam timer, M
is the cam timer motor, PM is the pump motor,
FSW indicates a float switch and L ₂ indicates an abnormality warning lamp. Further, the relay X1 includes normally open contacts 1a-1, 1a-2 and a normally closed contact 1b that cooperate with the relay X2, and the relay X2 includes a normally open contact 2a and a normally closed contact 2b that cooperate with the relay X3
1 is a normally open contact 31a-1 to 31 that cooperates with this
a-4 and normally closed contacts 31b-1 and 31b-2. In addition, the relay X32 has a normally open contact 32a and normally closed contacts 31b-1 to 32b that cooperate with it.
-3, and the relay X4 has a normally open contact 4a and a normally closed contact 4b cooperating therewith. Relay X
5 is a normally closed contact 5b-1, 5b- which cooperates with this.
2, but does not have a normally open contact. Furthermore, the relay X6 has normally closed contacts 6b-1,
6a-2 and a normally closed contact 6b, and the relay X7 has a normally open contact 7a and a normally closed contact 7b cooperating therewith.

Effects of the Embodiment Next, the development of effects over time of the operation control method according to the present invention when the refrigerator and electric control circuit according to the above-described configuration are operated will be described. Note that the present invention is a means proposed mainly to prevent the temperature inside the refrigerator from rising during defrosting operation.
First, we will explain the process from turning on the power to the refrigerator until the inside of the refrigerator is cooled to an appropriate temperature, and then we will describe the control process during defrosting operation.

(From turning on the power to cooling the inside of the refrigerator) Before operating the device, remove the front cover 5 of the cooling unit section 2 of the refrigerator, pull out the electrical box 13 toward you, and remove the lid 33 of the brine tank 8. The tank 8 is opened. Next, brine is injected into the brine tank 8, and the injection amount is the sum of the capacity of the brine 46 present in the circulation pipe system and the amount stored at the appropriate liquid level in the brine tank 8. . After the brine injection is completed, the lid 33 is reattached, the electrical equipment box 13 is inserted into a predetermined position, and the front cover 5 is attached to the cooling unit section 2.

When the power is turned on to operate the refrigerator, the power lamp _L1 lights up to indicate that the refrigerator is in operation. Since the internal temperature of the storage compartment is still maintained at about room temperature, the contact point of the internal thermostat Th ₃ equipped with the temperature sensing part 70 is "c-".
It closes between 'a'. Therefore, normally closed contact 5b-1 of relay X5 and normally closed contact 4b of relay
The relay X1 is energized via the
The CM and the condenser fan motor FM ₃ are activated and the operation of the refrigeration system 6 is started. At the same time, the pump motor PM for brine circulation is started and rotated via contacts a-c of the cam timer TM. In this cam timer TM, a built-in motor M starts rotating when the power is turned on, and the cooling time is integrated.

When the pump motor PM rotates, the brine 46 in the brine tank 8 is sucked through the suction pipe 39 and starts being supplied to the first cooler 17 via the discharge pipe 42 and the supply pipe 67. However, in the brine detection tank 51 disposed in the tank 8, the brine returned from the first cooler 17 is still present in the discharge pipe 4.
Since it does not flow down from 3, the float switch
The float 55a of the FSW (55) is located below, so its contacts a-b are open.

Also, since the relay X1 is energized, its normally open contact 1a-2 is closed, and the solenoid (not shown) of the solenoid valve _V2 is energized and opened via the normally closed contact 2b of the relay X2. The refrigerant from the refrigeration system is
It is circulated to the cooler 22. That is, the refrigerant is compressed by the compressor CM (60), condensed and liquefied in the condenser 7, passes through the dryer 62 and the electromagnetic valve _V2 , is depressurized in the capillary reach tube 65, and becomes a low-temperature liquefied refrigerant. The refrigerant flows into the cooler 22 of No. 2, evaporates there by exchanging heat with the air inside the refrigerator, and returns to the compressor CM from the suction pipe 66 as a gas refrigerant, repeating the cycle. Also, normally closed contact 2b of relay X2
The fan motor FM ₂ starts rotating via the normally closed contact 5b-2 of the relay Cooling of the inside of the refrigerator is started by discharging the fluid.

The first cooler 17 is fed by pressure from the pump motor PM.
After a while, the brine that has passed passes through the return pipe 68 and begins to flow down from the discharge pipe 43 into the brine detection tank 51. At this time, as described above, the amount of brine flowing out from the drain hole 53 formed in the bottom surface 51a of the brine detection tank 51 is set to be smaller than the amount of brine flowing into the tank 51 from the discharge pipe 43. There is. Therefore, part of the brine that has flowed down from the drain hole 53 to the brine tank 8, and most of it is stored in the brine detection tank 51, and its liquid level gradually rises. Due to this rise in the liquid level, the brine finally overflows from the upper edge 51c of the side wall of the detection tank 51 and begins to flow down into the brine tank 8 below. Further, the float 55a of the float switch FSW floats up as the liquid level in the tank 51 rises, and its contacts a and b are closed. That is, the closing of contacts a-b electrically detects that the brine is circulating in the first cooler 17.

In this way, contact a- of the float switch FSW
When b is closed, the relay X2 is energized via the normally closed contact 7b of the relay X7 and the a-c contacts of the cam timer TM, and in order to close the normally open contact 2a and open the normally closed contact 2b, the solenoid valve V ₂ The valve closes when the power is cut off, and the fan motor for the second cooler 22
FM ₂ stops its rotation. At the same time, normally open contact 2
By closing a, normally closed contact 32b of relay X32
-1, the solenoid valve _V1 opens, and the first cooler 1
Fan motor FM ₁ for 7 also starts rotating.

When the solenoid valve V ₂ that had been open until now closes and the solenoid valve V ₁ that had been closed opens, the flow of liquefied refrigerant from the refrigeration system 6 is switched to the third cooler 47 in the brine tank 8. Head towards. i.e. solenoid valve
The liquefied refrigerant that has passed through V ₁ is depressurized by the capillary reach tube 63 and flows into the third cooler 47, where it exchanges heat with the brine 46 in contact with this cooler 47 and evaporates, and the vaporized refrigerant returns to the suction pipe. The circulation cycle is repeated via 64 and back to the compressor.

The brine 46 that has exchanged heat with the third cooler 47 through the circulation of the refrigerant is cooled and its temperature gradually decreases. This cooled brine 46 is supplied to the first cooler 17 by the pump motor PM, where it exchanges heat with the air inside the warehouse to cool the inside of the warehouse. The brine whose temperature has increased due to heat exchange returns to the brine tank 8 from the discharge pipe 43 via the return pipe 68,
After being cooled by heat exchange with the third cooler 47, a series of circulation cycles toward the first cooler 17 are repeated.

When the cycle of cooling the inside of the refrigerator with the cooled brine is repeated, the temperature inside the refrigerator gradually decreases. In particular, when the amount of brine circulation is increased and the surface area of the first cooler 17 is increased, the amount of heat exchanged with the air inside the refrigerator increases. Moreover, since the temperature difference between the internal temperature and the first cooler 17 is extremely small, the first
The amount of frost on the cooler 17 is reduced, and the interior of the refrigerator is less dehumidified, so high humidity is maintained.

When the internal temperature of the refrigerator falls to a predetermined value, the internal thermostat _Th3 detects this, and the contact ca switches to the contact c-b in FIG. 7. Furthermore, the internal thermostat
When the temperature set for Th ₃ is 0° C. or higher, there is no frost on the first cooler 17, so contacts a-b of the defrosting thermometer Th ₁ attached to this cooler 17 do not close. However, if the set temperature of the internal thermometer Th ₃ is below 0°C, frost will form in the first cooler 17.
The defrosting thermometer _Th1 closes its contacts a and b before the internal thermostat _Th3 is activated (described later).

As mentioned above, the internal thermostat _Th3 operates and the contact c
When switching from -a to contact c-b, relay X1 is deenergized and rotation of compressor CM and fan motor FM ₃ is stopped. Also, contact c of internal thermostat Th ₃
-b and time limit contact c-d of timer T, relay X4 is energized and its normally open contact 4a is closed, so that relay X4 is self-held. At the same time, timer T is also energized and time measurement starts. When a predetermined period of time has elapsed, this timer T opens contacts c-d, deenergizes relay X4, opens normally open contact 4a, and releases self-holding.

When the operation of the refrigeration device 6 is stopped in this way,
Although the third cooler 47 no longer cools the brine,
The amount of brine stored in the brine tank 8 is
The amount is several times larger than the amount present in the circulation pipes, and since the brine tank 8 blocks heat from entering from the outside with the heat insulating material 32, it has a high cold storage effect. Therefore, the stored brine 46 is circulated by the pump motor PM and continues to cool the first cooler 17.

However, the temperature inside the storage warehouse gradually rises due to various causes such as heat entering from the outside through the heat insulating material 16, heat entering due to opening and closing of the door 4, and heat radiation from stored items. The first cooler 17 is also heated by the refrigerator air circulated by the fan motor FM ₁ , so that the brine circulating in the cooler 17 is also gradually warmed. Therefore, due to this warm brine, the temperature of the brine in the brine tank 8 also starts to rise gradually. When the temperature inside the refrigerator reaches the upper limit set temperature of the thermometer Th ₃ in the refrigerator, the contact point of the thermometer Th ₁ is switched from the "c-b" side to the "ca" side, and the timer T is turned off. Also, contact c-a of internal thermostat Th ₃ , normally closed contact 5 of relay X5
Relay X1 is energized via normally closed contacts 4b of b-1 and X4, closes its normally open contacts 1a-1, and resumes operation of compressor CM and fan motor _FM3 . Therefore, the refrigerant is circulated to the third cooler 47, and cooling of the brine 46 in the tank 8 is resumed.

The brine cooled by the third cooler 47 is
It is supplied to the first cooler 17 to cool the air inside the warehouse,
When the lower limit set temperature is reached, the contact point of the internal thermostat _Th3 switches from the "ca" side to the "cb" side, and the operation of the refrigeration device 6 is stopped. By repeating this process, the temperature inside the refrigerator is maintained at a constant temperature.

(Regarding Defrosting Operation) As already mentioned, the refrigerator according to this embodiment is mainly configured to circulate cooled brine through the first cooler 17 to cool the inside of the refrigerator.
Compared to regular refrigerators that use an evaporator as a cooling source, this brine cooling type refrigerator can circulate a large amount of brine with a high specific heat, which has the effect of reducing the difference between the internal temperature and the surface temperature of the cooler. There is.

However, if the temperature inside the refrigerator is set to around 0°C or below 0°C, the surface temperature of the first cooler 17 will be below 0°C, so moisture in the air will condense and freeze on the surface of the cooler, causing frost. It gradually forms in layers. When this frost grows large, as mentioned above,
This obstructs heat exchange between the first cooler 17 and the inside of the refrigerator, which not only makes it impossible to cool the inside of the refrigerator to the set temperature, but also causes problems such as lengthening the freezing time and increasing power consumption. The operation control method of the present invention is intended to effectively deal with this problem, and includes the first cooler 1
When the amount of frost formed in step 7 exceeds a predetermined value, cooling by this cooler is stopped and the following defrosting operation is started. In order to detect frost formation and start defrosting operation, there are two methods: directly detecting the amount of frost with a capacitance detector, integrating the time that internal thermometer Th ₃ is ON, and using the first cooler. The surface temperature of 17 is 0℃
Means for integrating the following times have been proposed, and any of them can be used in the method of the present invention. In this embodiment, a method using a cam timer, which is the cheapest in terms of cost, will be described.

During refrigeration operation, when the contact of the Cam TimerTM, which was connected between "a and c", switches to the "b and c" side,
At the same time as the operation of pump motor PM is stopped, relay X7 is energized, opening its normally closed contact 7b and closing its normally open contact 7a. Relay X2 is also deenergized, closing normally closed contact 2b and opening normally open contact 2a. When the brine circulation is stopped by stopping the pump motor PM, the brine detection tank 51
There is no overflow of brine at the drain hole 53, and the brine only flows down from the drain hole 53. Then, the brine level in the detection tank 51 gradually decreases,
The float 55a of the float switch FSW also gradually descends, and at a predetermined liquid level, the contacts a-b of the switch FSW
is open.

In other words, the float switch FSW closes contacts a and b of the float switch even when the cam timer TM switches to contacts b and c until the brine in the detection tank 51 drops to a predetermined level, thereby defrosting. This is to detect (judge) that brine circulation was performed and the first cooler 17 was cooled before operation.

Immediately after the Cam Timer TM switches to the contacts b-c, the relays X31 and X32 are energized via the contacts a-b of the float switch FSW, the normally open contact 7a of the relay X7, and the contacts b-c of the Cam Timer TM, respectively. Opens the normally closed contact and closes the normally open contact. In addition, relay X31 has its normally open contact 3
Self-maintaining by closing 1a-2. At this time, contacts a-b of the defrosting thermometer Th ₁ for the first cooler 17
is closed, normally open contact 32 of relay
a, Heater via contacts b-c of Cam TimerTM
H ₁ is energized and heats the first cooler 17 . Further, the rotation of the fan motor FM ₁ is stopped by opening the normally closed contact 31b-2 of the relay X31.

Further, the compressor CM and the fan motor FM ₃ are rotated via the normally open contact 31a-1 of the relay X31, and the operation of the refrigeration system is restarted. The fan motor FM ₂ for the second cooler 22 rotates via the normally closed contact 2b of relay X2 and the normally closed contact 5b-2 of relay X5, and the air inside the refrigerator is circulated as shown by the broken line in FIG. Circulate. As shown in the timing chart in Fig. 9, when the defrosting operation starts, if the internal thermometer _Th3 detects the lower limit set temperature and its contact is on the "c-b" side, relay X31 is activated. Normally open contact 31a
-4, Solenoid valve via normally closed contact 1b of relay X1
V ₁ opens and refrigerant from the refrigeration system flows into the third cooler 4.
7 to resume cooling the brine. Note that if the surface temperature of the first cooler 17 is so high that there is no frost on the first cooler 17, the defrosting thermometer _Th1 will not operate, and its contacts a and b will remain open, so there is no need to defrost. .

In this embodiment, frost formation occurs on the first cooler 17,
A case where contacts a-b of the defrosting thermometer _Th1 are closed will be described. After a while after switching to defrosting operation, the brine in the detection tank 51 flows into the liquid return hole 5.
3, the liquid level drops and the contacts a-b of the float switch FSW are opened, but as described above, the relay X31 continues to maintain itself through the normally open contacts 31a-2.

Next, when the temperature inside the refrigerator rises to the upper limit set temperature, the refrigerator thermometer Th ₃ is activated and the contact point is "c-b".
The relay X1 is energized via the normally closed contact 5b-1 of the relay X5 and the normally closed contact 4b of the relay X4. This opens the normally closed contact 1b of relay X1, and solenoid valve V ₁
At the same time, the solenoid valve V2 opens via the normally closed contact 2b of the relay X2 and the normally open contact 1a- ₂ of the relay X1. When the solenoid valve V ₂ is opened, the refrigerant from the refrigeration device 6 is circulated and supplied to the second cooler 22, and the air inside the refrigerator exchanges heat with the second cooler 22 to cool the inside of the refrigerator. In the horizontal refrigerator according to the embodiment shown in the figure, first coolers 1 are installed on the left and right side walls, respectively.
7 and the second cooler 22 are provided.
When defrosting the cooler 17, it is made less susceptible to the influence of cold air from the second cooler 22 so that the defrosting in the first cooler 17 is completed in a short time, and at the same time, there is no temperature difference in the refrigerator. This is to do so.

Next, when the temperature inside the refrigerator reaches the lower limit setting temperature of thermometer Th ₃ , its contact switches from the "ca" side to the "c-b" side, relay X1 is deenergized, and normally open contact 1a
-2 opens, the electromagnetic valve _V2 is de-energized and closed. At the same time, the solenoid valve _V1 is energized via the normally closed contact 1b of the relay X1 and opens. By opening this electromagnetic valve V ₁ , the refrigerant from the refrigeration device 6 flows into the third cooler 47 and circulates, thereby cooling the brine in the tank 8 . In other words, during defrosting of the first cooler 17, when the internal thermometer Th ₃ detects the upper limit set temperature and its contact switches to the "c-a" side, the second cooler 22 cools the inside of the refrigerator. is started, and when thermo Th ₃ detects the lower limit set temperature and switches its contact to the c-b side, the third cooler 47
Cooling of the brine is repeated.

When the frost on the first cooler 17 is heated by the heater H ₁ and melted and removed, the first cooler 17
temperature rises, and the defrosting thermometer _Th1 detects this temperature rise, opens contacts a and b, and cuts off the power supply to the heater _H1 . Shortly after the power to heater _H1 is cut off, the contact of the cam timer TM changes to "b-".
The state changes from the "c" side to the "a-c" side, and defrosting of the first cooler 17 is completed.

As mentioned above, while the first cooler 17 is defrosting, the refrigeration device 6 continues to operate, the second cooler 22 cools the inside of the refrigerator to keep the temperature inside the refrigerator constant, and the third cooler 47 continues to operate. The brine stored in the brine tank 8 is cooled. This cooling causes the temperature of the brine to be lower than it would be during a normal cooling process. The reason for supercooling the brine in tank 8 and lowering its temperature during defrosting is as follows.
It is as follows. That is, the temperature of the first cooler 17 increases as it is heated by the heater _H1 during defrosting, and therefore the temperature of the brine in the first cooler 17 also increases. When the next cooling stroke is restarted in this state, the rotation of the pump motor PM causes the first
The high temperature brine retained in the cooler 17 returns to the brine tank 8 and mixes with the brine stored in the tank 8, causing an inconvenience in that the temperature of the entire brine increases. However, in this example,
During defrosting, the freezing device 6 is forcibly operated continuously and the solenoid valves V ₁ and V ₂ are opened alternately, so that the temperature of the brine in the brine tank 8 becomes lower than that during the normal cooling process. There is. Therefore, even if the high-temperature brine and the brine in tank 8 mix, the temperature rise is slight and will not interfere with the next cooling process (the amount of brine stored in tank 8 is It is also several times the amount staying in the vessel 17.
(This is one of the reasons why the temperature rise is small.)

The contacts b-c of the Cam TimerTM are "a-c"
When switched to the side, the pump motor PM rotates and starts circulating the brine. In this case, if frost forms on the second cooler 22 during defrosting of the first cooler 17 and grows to a predetermined thickness or more, the corresponding defrost thermometer _Th2 is activated and contacts a and b are closed. do. This contact a-b and the normally open contact 31a of relay X31
-3, the relay X6 is energized, and the relay
6 closes its normally open contact 6a-2 and maintains itself. Therefore, by deenergizing relay X31, contacts a-b of defrosting thermometer _Th2 , normally closed contact 31b-1 of relay X31, and normally open contact 6a-1 of relay
Heater _H2 and relay X5 are energized via
Defrosting of the second cooler 22 is started. Note that since the normally closed contact 5b-1 of the relay X5 is opened, the power supply to the relay X1 is cut off, and the compressor CM and fan motor FM ₃ remain not operated.

With the start of brine circulation, brine is supplied to the detection tank 51 from the discharge pipe 43, and the liquid level in the tank 51 gradually rises, finally closing contacts a and b of the float switch FSW, and relay
The relay X2 is energized via the normally closed contact 7b of No.7. Then, the fan motor FM ₁ rotates via the normally open contact 2a of the relay X2 and the normally closed contact 31b-2 of the relay X31, and the first cooler 17 cools the air inside the refrigerator. In addition, normally open contact 2a of relay X2, normally closed contact 32b-1 of relay X32, and relay
The solenoid valve V1 is energized through the normally closed contact 1b of the valve _V1 and opens.

The second cooler 22 has an internal temperature setting of around 0°C.
Alternatively, if the temperature is 0° C. or lower, frost will form, so after the first cooler 17 has finished defrosting, the operation of the refrigeration device 6 is stopped and defrosting is performed. While the second cooler 22 is defrosting, the first cooler 17 is cooling the inside of the refrigerator. For example, when frosting progresses in the second cooler 22, the defrosting thermometer _Th2 detects this and connects contacts a-b.
is closed, and the second cooler 2 is turned on by energizing the heater _H2 .
Heat 2 to melt and remove frost. When the frost melts, contacts a-b of the defrost thermometer _Th2 are opened,
Power to heater _H2 and relay X5 is cut off, and defrosting ends. Also, relay X6 is released from self-holding. Note that the frost on the second cooler 22 is generated during the cooling operation during defrosting of the first cooler 17, and only a small amount is deposited during short-time operation. Frost ends in a short time.

When the defrosting in the second cooler 22 is completed, the relay X5
When the power is reduced, if a rise in the internal temperature is detected and the contact of the internal thermostat _Th3 is set to the "ca" side, the relay X1 is energized and the normally open contact 1a-1 is turned on. Close the compressor CM, fan motor
The FM ₃ is operated to cool the third cooler 47 in the brine tank 8 to lower the temperature of the brine, and the first cooler 17 cools the inside of the refrigerator. When the temperature inside the refrigerator reaches the lower limit set temperature, the contact point of the refrigerator thermometer Th ₃ goes to "c".
-b” side and stop cooling the brine.

As described above, the first cooler 17 basically cools the inside of the refrigerator, and while the first cooler 17 is defrosting, the second cooler 22 cools the inside of the refrigerator auxiliary. When the defrosting of the first cooler 17 is completed, if frost has adhered to the second cooler 22 used for auxiliary cooling, the second cooler 22 is defrosted,
By cooling the inside of the refrigerator with the first cooler, an increase in the temperature inside the refrigerator during defrosting is suppressed and the temperature is kept constant.

Effects of the Invention As explained in detail above, the refrigerator operation control method according to the present invention basically cools the inside of the refrigerator with the first cooler 17, and during defrosting of the first cooler 17, an auxiliary The second cooler 22 cools the inside of the refrigerator, and has the following beneficial effects.

(1) While the first cooler is defrosting the refrigerator, the second cooler cools the interior, and while the second cooler is defrosting, the first cooler cools the interior. Therefore, the rise in temperature inside the refrigerator during defrosting can be controlled to maintain a constant temperature inside the refrigerator.
Therefore, inconveniences such as deterioration of the quality of food stored in the refrigerator or accelerated thawing of frozen food during defrosting operation can be avoided in advance.

(2) While the first cooler is being defrosted, the refrigerator section continues to operate, and the second and third coolers are alternately cooled by switching the solenoid valve by opening and closing the internal thermostat. and keep the brine in the brine tank in a supercooled state. As a result, when defrosting is completed and cooling inside the warehouse is resumed in the first cooler, the supercooled brine is sent to the first cooler to bring the cooler to a low temperature in a short time. I can do it. In addition, the brine whose temperature has risen during the defrosting cycle returns to the brine tank and mixes with the supercooled brine to reach an appropriate temperature, so the temperature inside the refrigerator will not rise when cooling resumes in the first cooler. few.

(3) The interior of the refrigerator is mainly cooled by the first cooler of the brine circulation type, but since brine has a large specific heat, by setting the surface area of the first cooler to an appropriate value, the temperature inside the refrigerator and the temperature of the cooler can be adjusted. The difference from the surface temperature can be reduced. Therefore, the amount of coagulation (amount of frost formation) of moisture in the air inside the refrigerator that adheres to the first cooler is reduced, and the inside of the refrigerator can be kept at high humidity to prevent stored items from drying out.

(4) Due to the cold storage effect of the brine, the compressor stops operating for a long time, and the pressures on the high-pressure side and the low-pressure side of the refrigerant circulation system in the refrigeration system become equal. Moreover, since the temperature of the motor is lowered, restarting becomes easier, overload is reduced, parts life is extended, and power consumption is reduced because a small starting current is sufficient.

[Brief explanation of drawings]

The drawings show an embodiment of a refrigerator in which the operation control method according to the present invention is preferably carried out, and
The figure is a front view of a constant temperature and humidity refrigerator, Figure 2 is a front view with the cover removed from the cooling unit of the refrigerator, Figure 3 is a vertical cross-sectional view showing the schematic internal structure of the refrigerator, and Figure 4 is a brine. FIG. 5 is a vertical sectional view showing the schematic configuration of the detection device; FIG. 5 is a schematic perspective view showing the brine detection device shown in FIG. 4 with the lid removed; and FIG.
The figure is a schematic explanatory diagram showing the pipe connection state of the brine circulation circuit and the refrigerant circulation circuit from the refrigeration system incorporated in the refrigerator shown in Fig. 3. A circuit diagram showing an example of the control circuit. Figure 8 is a timing chart showing the behavior of each circuit element from power-on to cooling by the first cooler. Figure 9 is a timing chart showing the behavior of each circuit element from power-on to cooling by the first cooler. FIG. 3 is a timing chart showing the behavior of each circuit element. DESCRIPTION OF SYMBOLS 1... Box body, 2... Cooling unit part, 6... Refrigeration device, 8... Brine tank, 17... First cooler, 22... Second cooler, 47... Third cooler, 51 ...Brine detection tank, FM ₁ , FM ₂
...Fan motor, Th ₁ , Th ₂ ...Defrosting thermo,
Th ₃ ……Internal thermostat, H ₁ , H ₂ ……Heater, FSW
...Float switch, CM ...Compressor, V ₁ ,
V ₂ ... Solenoid valve.

Claims (1)

[Claims] 1. A storage compartment 1a defined inside the box 1 for cooling and storing foodstuffs, a refrigeration device 6 comprising a refrigerant compressor 60, a condenser 7, etc., and storing brine 46. a first cooler 17 arranged in the storage 1a and supplied with the brine 46 in the brine tank 8; a first cooler 17 arranged in the storage 1a and supplied with the refrigeration device 6;
a second cooler 22 to which refrigerant is supplied by opening a second solenoid valve (V ₂ ) which is normally closed; The refrigerant from the first
In the refrigerator configured with a third cooler 47 supplied via a solenoid valve (V ₁ ), during the defrosting period of the first cooler 17, the operation of the refrigeration device 6 is continued, and By stopping the supply of brine 46 in the brine tank 8 to the first cooler 17 and alternately switching the second solenoid valve (V ₂ ) and the first solenoid valve (V ₁ ), While the second solenoid valve (V ₂ ) is open, the second cooler 22 is operated for cooling to control the rise in temperature inside the refrigerator, and while the first solenoid valve (V ₁ ) is open, the third cooler 22 is operated for cooling. A method for controlling the operation of a refrigerator, characterized in that the brine 46 in the brine tank 8 is maintained in a supercooled state by operating the cooler 47 of the cooler 47 in a cooling operation.