JPH071140B2 - Operation control method for constant temperature and humidity refrigerator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a constant-temperature and high-humidity refrigerator using brine as a cooling medium, for example, by installing the refrigerator in a cold region, the internal temperature of the refrigerator drops below its lower limit set temperature. In such a case, the present invention relates to an operation control method of a constant temperature and high humidity refrigerator that can quickly restore the temperature inside the refrigerator while saving energy.

Prior art To store fresh food such as fruits, vegetables, meat and fish in a refrigerator for a long time in a frozen state, and to thaw the frozen food gradually,
Generally, it is necessary to manage the inside of the refrigerator at a constant temperature and high humidity so as to suppress the temperature change in the refrigerator as much as possible and prevent water evaporation from food.

As a means for responding to this request, a constant temperature and high humidity refrigerator using brine (antifreeze) as a cooling medium has been put into practical use. This is to cool brine in a brine tank by an evaporator that constitutes a refrigeration system, and circulate the cooled brine in a cooler arranged in a refrigerator to cool foods and the like. This brine-cooled refrigerator has a large cooling capacity because it circulates a large amount of brine with a large specific heat compared to a normal refrigerator that uses an evaporator as a cooling source, and is therefore suitable for cooling and storing a large amount of food. ing. Moreover, since the difference between the surface temperature of the cooler and the temperature inside the refrigerator can be made small, it is possible to prevent moisture in the air inside the refrigerator from condensing on the surface of the cooler to form frost, and keep the inside of the refrigerator in a high humidity state. can do.

However, even in a brine circulation refrigerator, if the temperature inside the refrigerator is set to around 0 ° C or below 0 ° C, the surface temperature of the cooler becomes 0 ° C or below, and frost gradually grows in layers on the surface. It will be. The frost removes moisture from the inside of the refrigerator to reduce the high humidity condition, and also hinders good heat exchange between the cooler and the air in the refrigerator to reduce the cooling capacity.
Therefore, the degree of frost formation is detected by an appropriate means, the circulation of brine is stopped, and the defrosting operation of melting and removing frost is performed by heating the cooler causing frost formation by means of a heater or the like. Will be needed.

As a means for detecting the frosted state in this cooler, there are known a direct detection method such as a capacitance type, a photoelectric type, and an electrode type, and an indirect detection method that performs a defrosting operation with a timer at regular intervals. ing. In either detection method, when the need for defrosting is detected and a defrosting operation is commanded, the operation of the refrigeration system and the brine circulation to the cooler are stopped, and the heater for promoting defrosting is energized. Heat the condenser. As a result, the frost grown in the cooler is melted, and when the surface temperature of the cooler rises to a predetermined temperature, the defrost thermostat detects this and stops energizing the heater. In order to prevent re-freezing of the molten water remaining on the cooler when the cooling operation is restarted, a certain draining time is set after the heater is de-energized. Restart circulation and switch to cooling operation.

By the way, the freezing temperature of the brine is generally -10 to -13.
It is about ℃. Brine having a lower freezing point can be selected, but at this time, the viscosity increases, the brine circulation amount decreases, and the cooling capacity also decreases. On the contrary, if a brine with a high freezing point is selected and used, the viscosity decreases, the brine circulation amount increases, and the cooling capacity increases. However, in the brine circulation refrigerator, since the inside temperature of the refrigerator and the brine temperature are substantially the same, when the inside temperature is set to, for example, -5 ° C, the brine temperature becomes substantially the same as the freezing point of the refrigerator. The fear that the brine in the brine tank will freeze during operation will occur. Therefore, a brine having the above-mentioned freezing point (-10 to -13 ° C) capable of keeping the viscosity of the brine moderate is generally used, thereby securing an appropriate brine circulation amount and preventing brine freeze.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As described above, in a constant temperature and high humidity refrigerator, the freezing point (-10 to-) that can keep the viscosity of brine moderate as an internal cooling medium
Brine with (13 ° C.) is commonly used. But,
Even in a constant temperature and high humidity refrigerator that employs this type of brine, the area where the refrigerator is used is a cold region or is used in a severe cold season, and the ambient temperature is a freezing point of the brine (for example, -10 to If the temperature drops below -13 ℃, the brine will freeze due to the ambient cold air that enters through the insulation of the brine tank. When the brine freezes, the circulation in the brine circulation system is stopped, the booster of the motor in the brine circulation pump locks, causing motor burnout, and the volume expansion of the brine causing the pipe connection and cooler to burst. There was a problem that caused a serious failure.

Further, even if the room temperature rises due to the start of heating in the room where the refrigerator is installed, the once frozen brine does not melt in a short time, and the brine circulation is stopped during that time. Therefore, it is pointed out that there is a problem in that the food is heated to a higher temperature due to poor cooling in the refrigerator, resulting in a decrease in freshness.

Especially during defrosting operation, the brine circulation is stopped and the frost adhering to the cooler is heated by a heating means such as a heater to melt and remove it. Defrosting in the cooler takes a long time due to the effect of cold air from the. Therefore, during the defrosting operation, the brine in the brine tank, the pump booster, and the brine in the piping of the brine circulation system are cooled by the external cold air and are frozen, so that there is a problem.

Therefore, the present inventor arranges a brine temperature detecting means at an appropriate position in the brine circulation system, and when the detecting means detects a predetermined temperature drop of the brine, the brine freeze detecting means such as a heater provided for the cooler is activated. Proposed prevention method. The inventor also proposed that when the temperature inside the refrigerator falls below the lower limit set temperature of the temperature detector, the antifreezing means is activated to keep the temperature inside the refrigerator within a predetermined temperature range.

However, when the freezing prevention means such as the heater is operated to control the internal cold storage temperature in the temperature range not lower than the brine freezing temperature and not higher than the internal cold storage lower limit temperature, the internal warming and Since the brine in the brine tank is also heated, there is a drawback that it takes time to raise the internal temperature. In addition, if you put hot food in the refrigerator,
Since the brine temperature is heated to almost the same temperature as the inside temperature, there is another problem to be solved, that is, it takes a lot of time to cool the hot food.

OBJECT OF THE INVENTION The present invention has been proposed in order to solve the above-mentioned brine circulation type constant temperature and humidity refrigerator in a cold region, or in view of the above-mentioned drawbacks inherent in the use in a severe cold season. It is an object of the present invention to provide a means for effectively utilizing heat storage above the freezing point of brine and shortening the heating time in the refrigerator to save energy.

Means for Solving the Problems In order to overcome the above-mentioned problems and preferably achieve the intended purpose, the operation control method for a constant temperature and high humidity refrigerator according to the present invention uses an evaporator that constitutes a part of a refrigeration system to perform brine control. Cool the brine in the tank, circulate the cooled brine in the cooler installed in the storage to cool the interior, and set the lower limit by the internal temperature detection device installed in the appropriate place in the storage. The temperature and a predetermined upper limit value are detected, the operation of the refrigeration system is turned on / off, the operation of the pump that circulates the brine is continued, and the temperature of the brine is lowered to near the freezing temperature due to the entry of outside air, When a brine temperature detecting device arranged at a proper position in the brine circulation system detects a predetermined lower limit value, the heat generating means attached to the cooler is operated and the brine circulation pump is operated to operate the brine circulation pump. In a constant temperature and high humidity refrigerator configured to prevent freezing, when the inside temperature detecting device detects that the inside temperature has dropped below a lower limit set temperature, the operation of the refrigeration system is stopped, and the inside temperature detecting device is When it is detected that the internal cold storage temperature further decreases from the lower limit set temperature and reaches a predetermined lower limit value, the operation of the brine circulation pump is stopped and the heating means is turned on. Characterize.

Further, also in order to overcome the above problems and preferably achieve the intended purpose, an operation control method for a constant temperature and high humidity refrigerator according to another invention of the present application is a method for controlling the temperature in a brine tank by an evaporator forming a part of a refrigeration system. The brine is cooled, and the cooled brine is circulated through a cooler installed in the storage to cool the inside of the storage. When the upper limit value is detected, the operation of the refrigeration system is turned on and off, the operation of the pump that circulates the brine is continued, and the temperature of the brine decreases to near the freezing temperature due to the entry of outside air, etc. When the brine temperature detection device installed at the appropriate position detects a predetermined lower limit value, the heating means attached to the cooler is activated and the brine circulation pump is operated to prevent the brine from freezing. In the constant temperature and high humidity refrigerator configured to, when the inside temperature detecting device detects that the inside temperature has dropped below the lower limit set temperature, the operation of the refrigeration system is stopped, and the inside temperature detecting device When it is detected that the temperature has further decreased from the lower limit set temperature and reached the predetermined lower limit value, the operation of the brine circulation pump is stopped and the heat generating means is turned on to set the inside temperature to the predetermined lower limit value and the lower limit value. When the temperature rises and falls with respect to the temperature, the heat generating means is correspondingly turned off and turned on, the operation of the brine circulation pump is held in a stopped state, and the inside temperature once lowered to the predetermined lower limit is reached. When the temperature rises and reaches the lower limit set temperature, the operation of the brine circulation pump is not restarted, and when the internal temperature exceeds the lower limit set temperature and reaches the predetermined upper limit value, the operation is stopped. The operation of the refrigeration system is restarted, and the operation of the brine circulation pump, which has also been stopped, is restarted.

Example Next, the operation control method of the constant temperature and high humidity 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 capable of suitably implementing the operation control method.

(Regarding Schematic Structure of Refrigerator) A refrigerator capable of suitably implementing the operation control method according to the present application is
As shown in FIG. 1 and FIG. 2, from a box body 1 and a cooling unit section 10 that define a horizontally long storage case 1a for internally storing stored items such as frozen foods (hereinafter referred to as “food materials”) by cooling. Therefore, the top plate 11 is commonly arranged on both sides. Storage 1a
A door 12 is rotatably and pivotally supported at an opening of the storage box, and a mounting shelf (not shown) is horizontally provided inside the storage case 1a in a detachable manner. The cooling unit section 10 includes a compressor CM, a fan motor FM ₃ (Fig. 4) and a refrigeration unit 4 including a condenser 3 and the like.
A brine cooler 13 including the brine tank 6 and an electrical equipment box 17 (having an internal temperature controller 15, a thermometer 16 and the like) are provided.

In the cross section of the essential parts of the constant temperature and high humidity refrigerator shown in FIG. 2, a heat storage material 20 is filled between an outer box 18 and an inner box 19 which form the box 1, and a storage box 1a defined in the inner box 19 is formed. A cooler 7 to which brine as a cooling medium is circulated and supplied is fixedly arranged on the upper left surface inside the. A cooling duct 21 having an open left side is arranged below the cooler 7 to cover the cooler 7 in a non-contact state. A required opening 22 is formed on the right side of the cooling duct 21 as shown in the drawing.
The two cold air circulation fan motors FM ₁ and FM ₂ (only one of which is shown in the figure) arranged in the inside of the refrigerator suck the indoor air from the gap on the left side of the cooling duct 21 and contact the cooler 7 for heat exchange. After being cooled by cooling, it is blown out from the opening 22 and circulates as shown by the solid arrow to cool the entire inside of the storage case 1a.

As shown in FIG. 4, a defrosting thermostat Th ₁ that detects the end of defrosting and heaters H ₁ and H ₂ for defrosting are arranged near the cooler 7. Further, a dew tray 27 is arranged below the cooler 7, and water droplets dropped from the cooler 7 at the time of defrosting are collected here and discharged to the outside of the refrigerator. Note that reference numeral 28 indicates a temperature-sensing portion of the in-compartment temperature detection thermos Th ₂ which is arranged in a proper place in the refrigerator. Further, a brine freezing temperature detecting thermo-th ₃ for detecting the freezing temperature of the brine 8 stored in the brine tank 6 which will be described later is provided, and the temperature sensing part thereof is immersed in the brine 8.

(Brine Cooling Unit) FIG. 3 shows a brine cooling unit 13 that cools the brine by the refrigerating device 4 and circulates and supplies the brine to the cooler 7 as a refrigerant. This brine cooling unit 13 has a heat insulating material 31.
It has a brine tank 6 consisting of an outer box 29 and an inner box 30 which are filled with an interposer, and its upper opening can be removed by a lid body 35 composed of an upper lid 32 and an inner lid 33 which also interpose a heat insulating material 34. Is covered by. Further, each end edge portion of the upper lid 32 is bent at a right angle and is fitted into the outer box 29 of the tank 6 so that the upper edge portion of the tank 6 and the inner lid 33 come into close contact with each other. The end of the upper lid 32 is detachably fixed to the tank outer box 29 via a bolt.

One end of a suction pipe 36 is connected to a lower portion of a side wall of the inner tank box 30, the suction side of the brine circulation pump PM is connected to the other end of the suction pipe 36, and the pump discharge side is connected to the cooler 7. It is connected to the brine supply pipe 9. Also inner box
Discharge pipe that bends in a key shape and opens downward on the upper side wall of 30
37 is exposed, and the other end of the discharge pipe 37 is connected to the brine return pipe 14 from the cooler 7. In addition, these suction pipes 36,
The supply pipe 9, the discharge pipe 37, and the return pipe 14 are all insulated by a heat insulating hose 38. Further, a concave support plate 39 is fixed to the inner bottom portion of the tank 6, and an evaporator 40, which is drawn from the refrigerating device 4 and wound in a spiral shape, is arranged with the support plate 39 with its axis line horizontal, The brine 8 stored in 6 at a predetermined liquid level can be cooled to a required temperature.

The liquid level of the brine 8 stored in the brine tank is
The brine 8 in the pipeline connecting the cooler 7 and the tank 6 is disposed at a level lower than the cooler 7 arranged in the refrigerator, so that the cooler 7 and the tank 6 are connected to each other during the defrosting operation described later. All are returned to the tank 6 without remaining.

(Refrigeration Circuit and Brine Circulation Circuit) FIG. 4 is a schematic system diagram of each pipeline system that constitutes a refrigeration circuit and a brine circulation circuit using a liquefied / vaporized refrigerant such as Freon. In the figure, the vaporized refrigerant compressed by the compressor CM becomes a liquefied refrigerant in the condenser 3, is dehumidified by the dryer 41, and is then decompressed by the capillary tube 42. Then, the brine 8 in the brine tank 6 is cooled by evaporating in the evaporator 40. The vaporized refrigerant that has evaporated returns to the compressor CM again via the suction pipe. Reference numeral FM ₃ shows a fan motor for cooling a condenser 3.

Further, in the brine circulation circuit, the brine 8 in the tank 6 is
Is cooled to a required temperature by an evaporator 40 which constitutes a part of the refrigerating apparatus 4, and the cooled brine 8 is sucked out by a circulation pump PM through a suction pipe 36 and then connected to a discharge side. It is supplied from the brine supply pipe 9 to the cooler 7. The brine 8 exchanges heat with the air in the refrigerator in the cooler 7, and then is returned to the tank 6 via the brine return pipe 14 and the key-shaped discharge pipe 37.

FIG. 5 shows an electric control circuit of the constant temperature and humidity refrigerator shown in the embodiment. In the figure, the cam timer T is connected between the power supply lines A and B.
M is connected, and the movable contact c provided on the line B side of the cam timer TM is connected to the fixed contact a side during the cooling operation and switched to the fixed contact b side during the defrosting operation by the timer drive motor M. . First contact Th ₂ -a of the internal thermo Th ₂ is
The movable contact c is connected to the line A, and the compressor CM and the fan motor are connected between one fixed contact a (closed at the internal upper limit set temperature T ₁ ) and the fixed contact a of the cam timer TM. FM ₃ is connected in parallel. See also Cam TimerTM
A relay X ₄ is connected between the fixed contact a and the connection point k of
Furthermore between the connection point k to the other fixed contact b of the first contact Th ₂ -a (closing in the internal lower limit set temperature T _0), the normally open contact X ₃ -1a and the relay of the relay X ₃ the normally open contact X ₄ -a in X ₄ are connected in parallel. This normally open contact X ₄ − functions as a self-holding contact for the relay X ₄ .

Note the first thermo contact Th ₂ -a of until the internal temperature T reaches the predetermined upper limit value T ₁ rises is closed is between the contacts c-b, contact c reaches a predetermined upper limit value T ₁ -B is opened and contact c-a is closed. Further, the contact point c-a is closed until the internal temperature T decreases and reaches a predetermined lower limit value T ₀ (T ₀ <T ₁ ), and when the predetermined lower limit value T ₀ is reached, the contact point c-a is closed. Is opened and the contact c-b is closed.

Fan motors FM ₁ and FM ₂ are connected in parallel between line A and fixed contact a of cam timer TM, and line A and connection point L
Between the contacts Th ₁ defrost thermo Th ₁ is inserted.
The thermo-contact Th ₁ is set so as to close (open when the temperature of the cooler 7 is below a predetermined value). Furthermore between the fixed contact b of the connecting point L and Kamutaima TM, relay X ₁ and the heater through the normally closed contact X ₂ -b relay X ₂
H ₁ and H ₂ are connected in parallel. Also between the fixed contact b and the line B of Kamutaima TM, the normally open contact X ₂ -1a relay X ₂
And the normally open contact X ₃ -2a relay X ₃ are connected in parallel.

Between the line A and the connection point N, it is connected to the normally closed contact X ₁ -b to relay X ₁ cooperate, between the connection point N and the line B, normally closed relay X ₄ connected in parallel A pump motor PM and a timer drive motor M are connected to each other via a contact X ₄ -b and a relay X ₂ normally open contact X ₂ -2a. Between lines A and B,
Brine freezing temperature and the contact Th ₃ of brine freezing temperature sensing thermo Th ₃ for detecting a relay X ₂ are connected in series. Note the thermo Th _3, the temperature is the predetermined lower limit value TA of the brine 8
When it becomes, the contact is closed, and when the predetermined upper limit value TB is reached, it is controlled to open (TA <TB).

Between further line A · B, a second contact of the internal thermo Th ₂ Th ₂
Relay X ₃ through a -b are connected. This second contact
The contact of Th ₂ -b is opened at the lower limit set temperature T ₀ in the refrigerator, and when the predetermined lower limit value T ₂ is reached from the lower limit set temperature T ₀ , the contact is closed. That second contact Th ₂ -b, as shown in FIG. 6, between the T ₀ → T ₂ opening, between the T ₂ → T ₀ closed, open at T ₀ or more, closing the T ₂ or less Take action.

(Operation of Constant Temperature and High Humidity Refrigerator) Next, the actual operation of the constant temperature and high humidity refrigerator according to the embodiment will be described with reference to the timing chart shown in FIG. Prior to operation, first, the lid 35 of the brine tank 6
Remove and inject brine 8. The injection amount is a value obtained by summing the capacity of the brine 8 existing in the circulation conduit system and the amount of the proper liquid level stored in the tank 6.

Since the internal temperature T is higher, the first contact Th ₂ -a of the internal thermo Th ₂ is between the c-a is closed. Further, the cam timer TM is switched between the contacts a and c. Therefore, when the power switch is turned on, the compressor CM and the fan motor FM ₃ of the refrigeration system are activated to start the operation of the refrigeration system. The power is supplied to the motor M of Kamutaima TM through the normally closed contact X ₁ -b relay X _1, counting of the time limit time is started. Further energized the brine circulation pump PM through the normally closed contact X ₄ -b normally closed contact X ₁ -b and the relay X _4,
The brine 8 in the tank 6 is circulated and supplied from the discharge pipe 9 to the cooler 7.

Brine 8 pumped by pump PM and passed through cooler 7.
After exchanging heat with the air in the refrigerator, it returns from the discharge pipe 37 into the tank 6 via the return pipe 14. Then, the returned brine 8 is mixed with the cooled storage brine 8 in the tank 6, and is again circulated by the pump PM via the suction pipe 36. At this time, since the fan motors FM ₁ and FM ₂ in the refrigerator are rotating, the air that has been forcibly brought into contact with the cooler 7 for heat exchange is circulated in the refrigerator. Gradually decreases. When the circulation amount of the brine 8 is increased and the surface area of the cooler 7 is increased, the amount of heat exchange with the air in the cold storage increases, and the temperature difference between the cold storage temperature and the cooler 7 becomes extremely small. Therefore, the amount of frost on the cooler 7 is reduced, and high humidity is maintained.

When the internal temperature decreases and the temperature T reaches the lower limit set temperature T ₀ of the internal thermostat Th ₂ , c of the first thermocontact Th ₂ -a.
-A is opened and c-b is closed, compressor CM
And stop the operation of fan motor FM ₃ . Since the pump PM and the fan motors FM ₁ and FM ₂ continue to operate, the brine 8 continues to circulate in the pipeline system to continue cooling the inside of the warehouse.

By the way, the internal temperature T rises over time under the influence of heat entering from the outside, heat generation of the fan motors FM ₁ and FM ₂ and heat radiation from foods, etc., whereby the brine that exchanges heat with the internal air is generated. The temperature of 8 also rises. When the internal temperature T rises to the upper limit set temperature T ₁ of the internal thermo Th ₂ ,
With between c-b of the first thermo-contact Th ₂ -a is opened,
The space between c and a is closed, the compressor CM and the fan motor FM ₃ are started, and the interrupted cooling operation is restarted. By repeating the above cycle, the internal temperature will be the upper limit set temperature.
It is maintained between T ₁ and the lower limit set temperature T ₀ . During this period, frost adheres to the surface of the cooler 7 and gradually grows in layers.

A predetermined time has passed while the cooling operation described above is repeated,
When the cam timer TM times out, the contacts are switched to the bc side, all of the compressor CM and the fan motors FM ₁ , FM ₂ and FM ₃ are stopped, and the refrigerator is defrosted. Since that is the temperature of the cooler 7 is sufficiently low at this time, contact Th ₁ defrost thermo Th ₁ is in a closed state. The temperature of the brine 8 is the lower limit TA of the brine freezing temperature detection thermometer Th _3.
Since higher, contact Th ₃ of the sensing thermo Th ₃ is open, thus power supply to the heater H _1, H ₂ and the relay X ₁ is started. By the excitation of the relay X _1, the normally closed contact X ₁ -b which cooperates with this opening, the pump PM and the timer motor M stops its rotation.

Since the heating of the cooler 7 by the heaters H ₁ and H ₂ is sufficient only for the outer surface, defrosting is performed in a short time, and the melted water of frost drops on the dew tray 27 and is discharged to the outside of the refrigerator. Although the pump PM is stopped, as described above, the cooler 7 is located above the brine liquid level in the tank 6, so that all the brine in the pipeline system returns to the inside of the tank 6, and thus the brine 8 is Not heated by heaters H ₁ and H ₂ .

Since the temperature of the cooler 7 rises when it is defrosted, the defrosting thermo Th ₁ detects this and opens the contact Th ₁ to cut off the power supply to the heaters H ₁ and H ₂ and the relay X ₁ . When the relay X ₁ is de-energized, the normally closed contact X ₁ -b cooperating therewith closed again, energization of the pump PM and the timer motor M is started. At this time, the contact point of the cam timer TM is on the bc side, so that neither the compressor CM nor the fan motors FM ₁ , FM ₂ and FM ₃ are operating. Then, by rotating the pump PM, the brine 8 in the tank 6 is circulated and supplied to the cooler 7. The brine 8 in the tank 6 is stored with cold due to its large heat capacity. Therefore, even if the brine 8 is not subjected to the positive forced cooling by the evaporator 40, the brine 8 is circulated through the cooler 7 to cool it, and the vicinity of the cooler is Cool and reduce the temperature inside the chamber rapidly.

Further, since energization of the timer drive motor M is also started, the contact of the cam timer TM is switched to the ac side after a while, and the above-mentioned cooling operation is restarted. In this way, the internal temperature T is controlled between the upper limit set temperature T ₁ and the lower limit set temperature T ₀ of the internal thermo-contact Th ₂ . The brine 8
The difference between the temperature and the internal temperature T is adjusted to be approximately 1 to 3 ° C.

Next, due to various factors, the internal temperature T is set to the lower limit temperature T ₀
A case in which it is lower than the above will be described. The temperature T in the refrigerator is lower than the lower limit set temperature T ₀ when a large amount of frozen foods kept at a temperature lower than the set temperature T ₀ is stored in the storage cabinet and thawed, etc., in a cold region. There is a case where the ambient temperature of the refrigerator falls below the lower limit temperature T ₀ inside the refrigerator due to use or during severe cold season, etc., and cold air outside the refrigerator enters the refrigerator via heat insulating materials etc. However, in the embodiment, the latter case will be described.

As shown in the timing chart of FIG. 6, the in-compartment temperature T gradually falls below the lower limit set temperature T ₀ of the in-compartment thermostat Th ₂ . When the internal temperature T falls below the temperature T ₀ , the first contact Th ₂ -a of the internal thermostat Th ₂ is opened between ca and closed between c and b, so that the compressor CM and the fan are closed. motor
FM ₃ stops its operation.

When the internal temperature T further drops and reaches a temperature T ₂ which is lower than the temperature T ₀ by a predetermined value, the second thermo-contact Th ₂ -b of the internal thermo Th ₂ is closed and the relay X ₃ is closed. excitation to the first and second normally open contact X ₃ -1a, closes the X ₃ -2a. This first
The closing of the normally open contact X ₃ -1a, the first thermo-contact Th ₂ -a
Relay X ₄ is excited via the c-b side of the
Self hold the relay X ₄ by closing the X ₄ -a. The opening is normally closed contact X ₄ -b relay X _4, to stop the brine circulation by blocking the power supply to the pump motor PM. Note that the brine in the cooler 7 flows down to the brine tank 6 and is collected when the pump is stopped. Furthermore the second normally open contact X ₃ of the relay X ₃ -
The closing of 2a energizes the heaters H ₁ and H ₂ and the relay X ₁ to heat the cooler 7 by the heaters H ₁ and H ₂ .

When the cooler 7 is heated and its temperature rises, the air forcedly circulated by the rotating internal fan FM ₁ , FM ₂ comes into contact with the cooler 7 for heat exchange, and the internal temperature T gradually rises. start. On the other hand, the temperature of the brine 8 in the brine tank 6 is
The cold air entering through the heat insulating material 31 of the brine tank 6 gradually descends as shown by the one-dot chain line in FIG.

As previously described, the inside temperature T is the temperature rise by heat of the heater H _1, H _2, and reaches the lower limit set temperature T ₀ of the internal thermo Th _2, the second contact Th ₂ -b of said thermo Th ₂ Open to relay X ₃
Is depressed. Therefore, the first normally open contact X ₃ −1a of relay X ₃
However, the relay X ₄ continues to hold itself by closing the normally open contact X ₄ -a, so the pump motor PM remains stopped. Further, the second normally open contact X ₃ -2a of the relay X ₃ is also opened at the same time to cut off the energization to the heaters H ₁ and H ₂ and stop the heating of the cooler 7.

Here the reason the upper limit operating values of the second contact Th ₂ -b at the internal thermo Th _2, are set to the same as the internal limit set value T ₀ is to effectively prevent the waste of power. That is,
To raise the internal temperature T to the upper limit set value T ₁ , use a heater
When H ₁ and H ₂ are heated to reach the set value T ₁ , the refrigerating system must be operated to lower the internal temperature T to the lower limit set temperature T ₀ . While the inside temperature T is again lowered from the lower limit set value T _0, by repeating the above operation, the inside temperature T is temperature T ₂ and the lower limit set temperature T drops by a predetermined value than the lower limit set temperature T ₀ Controlled between ₀ and.

The temperature of the brine 8 drops to about the same as the ambient temperature of the refrigerator due to the entry of outside air, and when the ambient temperature is lower than the freezing temperature of the brine 8, the temperature of the brine 8 is determined by the timing chart of FIG. It drops further than the one-dot chain line shown in. Then, when the temperature drops to the lower limit operation value TA of the brine freezing temperature detection thermo Th ₃ , the thermo Th ₃ closes its contact and excites the relay X ₂ . Together thereby closing the normally open contact X ₂ -1a relay X _2, the X ₂ -2a, normally closed contacts X ₂ -b
Open up. Then, the heaters H ₁ and H ₂ are energized to cool the cooler 7.
Is started, the pump motor PM is also energized to circulate the brine 8 to the cooler 7. The brine 8
Is returned to the brine tank 6 after being heated by heat exchange in the cooler 7, and raises the temperature of the entire brine stored in the tank 6. When the temperature of the brine 8 reaches the upper limit value TB in the brine freezing temperature detection thermo Th ₃ , the contact of the thermo Th ₃ is opened and the relay X ₂ is deenergized, so that the heaters H ₁ and H ₂ are de-energized. Made and brine 8
Heating is stopped. In this way, the brine anti-freezing device operates to prevent the brine from freezing.

By the way, in practice, there are many cases where the temperature is between the lower limit set value T ₀ of the thermostat Th _{3 in} the refrigerator above the temperature at which the brine antifreeze operates, so next, in this temperature range Explain the behavior. While the internal temperature T is regulated and controlled between the lower limit set temperature T ₀ and the predetermined temperature T ₂ , the brine 8
Is cooled by the above-mentioned strong invasion of outside air and its temperature is lowered, so that it is in a so-called cold storage state.

In this case, the temperature T in the refrigerator may suddenly increase due to a rapid increase in ambient temperature due to heating, frequent opening of doors, and the addition of a large amount of high-temperature food. When the interior temperature T reaches the upper limit set value T ₁ of the storage room thermo Th _2,
Since between the first thermo contact Th ₂ -a of c-b is closed is between c-a with is opened, the self-holding of the relay X ₄ is released. Therefore, the relay X ₄ is deenergized and the normally closed contact is made.
X ₆ -b is closed, resume the operation of the pump motor PM. The compressor CM and fan motor FM ₃ are also energized, and the brine 8
Resume cooling. The brine 8 is stored at the temperature as described above and has a large temperature difference from the internal temperature T.
The cooler 7 is cooled rapidly by the increased cooling capacity. Therefore, the internal temperature T drops from the 0 point to the lower limit set temperature T ₀ in a short time, and the temperature of the hot food stored in the storage is quickly lowered, so that the freshness of the food can be maintained. When the outside air temperature is lower than the lower limit set value T ₀ , when the frozen food is put into the refrigerator and thawed, only the frozen food is added without heating the brine 8 by the heaters H ₁ and H _2. Since it can be thawed for a short time, thawing for a short time is realized.

As described above, the operation control method of the constant temperature and high humidity refrigerator according to the present invention, the defrosting promotion means in the temperature range below the lower limit set value of the internal thermostat and until the antifreezing device operates. The control for activating and stopping the brine circulation means is preferably performed. According to this method, since the brine is not heated, the power consumption required to maintain the temperature inside the refrigerator is small, and even if the temperature inside the refrigerator suddenly rises, the negative temperature of the stored cold brine is reduced. By storing heat, the inside of the refrigerator can be cooled in a short time, effectively maintaining the freshness of the food. Further, it can be applied to rapid cooling of high-temperature foods and thawing of frozen foods for a short period of time.

[Brief description of drawings]

The drawings show a refrigerator in which the operation control method of a constant temperature and high humidity refrigerator according to the present invention can be suitably implemented, and FIG. 1 is a front view showing a state in which a cover is removed from a cooling unit section of a constant temperature and high humidity refrigerator, 2 is a vertical cross-sectional view showing the internal schematic structure of the refrigerator, FIG. 3 is a vertical cross-sectional view of the brine tank, and FIG. 4 is a brine circulation circuit incorporated in the refrigerator shown in FIG. 2 and a refrigerant circulation circuit from the refrigeration system. FIG. 5 is a schematic explanatory view showing a pipe connection state, FIG. 5 is an electric control circuit diagram for controlling the constant temperature and humidity refrigerator shown in FIG. 1, and FIG. 6 is a timing chart explaining an operation of the electric control circuit diagram shown in FIG. It is a figure. 1a ...... storage case, 4 ...... refrigerating apparatus 6 ...... brine tank, 7 ...... cooler 8 ...... brine, 40 ...... evaporator H ...... heater Th ₃ ...... brine freezing temperature sensing Thermo

Claims (2)

[Claims] 1. A brine (8) in a brine tank (6) by an evaporator (40) which constitutes a part of a refrigeration system (CM, FM ₃ ).
To cool the cooled brine (8) to the storage (1
a) A cooler (7) arranged in the inside cools the inside of the refrigerator to cool the inside of the refrigerator, and an inside temperature detecting device (Th
₂ ) The lower limit set temperature (T ₀ ) and the predetermined upper limit value (T ₁ ) are detected by ( ₂ ) to turn on / off the operation of the refrigeration system (CM, FM ₃ ) and circulate the brine (8). (PM)
Operation continues, the temperature of the brine (8) drops to around the freezing temperature due to the entry of outside air, etc., and the brine temperature detection device (Th ₃ ) installed in the proper place in the brine circulation system keeps the predetermined lower limit value (TA). When detected, heat generating means (H ₁ , H ₂ ) attached to the cooler (7)
In the constant temperature and humidity refrigerator configured to operate the brine circulation pump (PM) and to prevent the brine (8) from freezing, the inside temperature detecting device (Th ₂ ) is When it is detected that (T) has fallen below the lower limit set temperature (T ₀ ), the operation of the refrigeration system (CM, FM ₃ ) is stopped, and the inside temperature detection device (Th ₂ ) detects the inside temperature (T ₂ ). ) Further decreases from the lower limit set temperature (T ₀ ) and reaches a predetermined lower limit value (T ₂ ), the brine circulation pump (PM) is detected.
The method for controlling the operation of a constant temperature and high humidity refrigerator, characterized in that the operation of ( ₁ ) is stopped and the heating means (H ₁ , H ₂ ) is turned on. 2. A brine (8) in a brine tank (6) by an evaporator (40) forming a part of a refrigeration system (CM, FM ₃ ).
To cool the cooled brine (8) to the storage (1
a) A cooler (7) arranged in the inside cools the inside of the refrigerator to cool the inside of the refrigerator, and an inside temperature detecting device (Th
₂ ) Detects the lower limit set temperature (T ₀ ) and the predetermined upper limit value (T ₁ ) to turn on / off the operation of the refrigeration system (CM, FM ₃ ) and circulate the brine (8) ( PM) operation continues, the temperature of the brine (8) drops to around the freezing temperature due to the entry of outside air, etc., and the brine temperature detection device (Th ₃ ) installed in the proper place in the brine circulation system has reached the predetermined lower limit (TA). ) Is detected, the heat generating means (H ₁ , H ₂ ) attached to the cooler (7) is detected.
In the constant temperature and humidity refrigerator configured to operate the brine circulation pump (PM) and to prevent the brine (8) from freezing, the inside temperature detecting device (Th ₂ ) is When it is detected that (T) has fallen below the lower limit set temperature (T ₀ ), the operation of the refrigeration system (CM, FM ₃ ) is stopped, and the inside temperature detection device (Th ₂ ) detects the inside temperature (T ₂ ). ) Further decreases from the lower limit set temperature (T ₀ ) and reaches a predetermined lower limit value (T ₂ ), the operation of the brine circulation pump (PM) is stopped and the heat generating means (H ₁ , H ₂ ) is turned on, and when the internal temperature (T) rises / falls between a predetermined lower limit value (T ₂ ) and a lower limit set temperature (T ₀ ), the heat generating means (H ₁ , H
₂ ) is turned off / on correspondingly, the operation of the brine circulation pump (PM) is held in a stopped state, and the internal temperature (T) once lowered to the predetermined lower limit value (T ₂ ).
When the temperature rises and reaches the lower limit set temperature (T ₀ ), the operation of the brine circulation pump (PM) is not restarted, the internal temperature (T) exceeds the lower limit set temperature (T ₀ ), and the predetermined upper limit is reached. When the value (T ₁ ) is reached, the refrigeration system (CM, F
A method for controlling the operation of a constant temperature and high humidity refrigerator, characterized in that the operation of the brine circulation pump (PM) that was also stopped is restarted when the operation of M ₃ ) is restarted.