JP2002206814A - Rapid freezing cycle device and rapid freezing method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rapid freezing cycle device and a rapid freezing method using the same in which a maximum freezing capability can be realized over a wide range of evaporating temperature and further a freezing processing capability can be improved. SOLUTION: There is provided a rapid freezing cycle device 1 in which compressors 3, 5, a condenser 9, an expansion valve 15 and an evaporator 17 are connected in series in an annular form by a refrigerant pipe. In this rapid freezing device, a first compressor 3 and a second compressor 5 are arranged side by side in which freezing capabilities are reversed to each other with an interface of a predetermined evaporating temperature of refrigerant. There is provided an operation controller for detecting the evaporating temperature and changing over its operation to the compressors 3, 5 where a high freezing capability can be attained at the detected temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rapid refrigeration cycle apparatus and a rapid refrigeration method using the same.

[0002]

2. Description of the Related Art Conventionally, various types of refrigerating apparatuses for preserving and preserving the freshness of food and the like for a long time have been developed and used.
The problem of drip (leaching sap when thawing) when freezing fresh food is not sufficiently solved. This drip is generated when ice in the fresh food freezes, and ice crystals grow excessively large and become coarse, thereby destroying cell tissues, that is, the ice crystals grow -1.
This is due to the long transit time in the temperature range of -5C. Therefore, the present applicant has previously developed a rapid refrigeration apparatus that can pass through this temperature range in an extremely short time, and has solved this problem.

This quick freezing apparatus comprises a hermetic freezer having a door for taking in and out a frozen object such as fresh food, a magnetic field generating means for applying a magnetic field to the freezer, and a quick freezer for cooling the inside of the freezer. A refrigerating cycle device, wherein the rapid refrigerating cycle device is configured by annularly connecting a compressor, a condenser, an expansion valve, and an evaporator by a refrigerant line. And
The frozen object placed in the refrigerator is cooled while applying a magnetic field to make the water inside the object in a supercooled state, so that it passes through the temperature range in a very short time, and finally has a temperature of approximately −50. ° C
It is frozen to extremely low temperatures.

[0004] However, since the rapid freezing apparatus is of a batch type, in each freezing process, the door is opened and closed, the object to be frozen is carried into the refrigerator, placed, and after the freezing, the door is opened. Take the procedure of unloading. Therefore, every time the freezing process is performed, the temperature in the refrigerator is generally lowered from room temperature by -6 ° C.
The temperature must be lowered to 0 ° C., and the temperature reduction takes a considerable amount of time. As a result, the refrigerating capacity is extremely low, and further improvement is desired.

In order to increase the cooling rate, the refrigerating capacity Q (kW) of the rapid refrigerating cycle device may be increased. The refrigerating capacity mainly depends on the type of the compressor and the evaporation temperature of the refrigerant. Change. Generally, the refrigerating capacity decreases as the evaporation temperature of the refrigerant decreases, and its falling curve is determined mainly by the type of the compressor. For example, FIG. 2 shows the refrigerating capacity characteristics of a single-stage compressor and a two-stage compressor having a nominal output of 7.5 kW of an electric motor, and the vertical axis represents the refrigerating capacity.
The evaporating temperature of the refrigerant is shown on the horizontal axis, and the characteristics of the single-stage compressor have a downwardly convex curve in which the refrigerating capacity monotonously decreases with a decrease in the evaporating temperature. In the range from the lower limit temperature of use to -35 ° C, it is a composite curve which is located substantially above the curve along the curve, and has a constant refrigeration capacity at -35 ° C or higher (for details, see below).
Therefore, the refrigerating capacity of these two compressors is approximately -3.
Inverted around 1 ° C, the single-stage compressor has a higher refrigeration capacity on the higher side than the boundary temperature, and the two-stage compressor has a higher refrigeration capacity on the lower side. Has a limited evaporating temperature range in which it can exhibit high refrigeration capacity.

On the other hand, in the above-mentioned rapid refrigeration apparatus,
The inside of the refrigerator must be cooled in a wide temperature range from room temperature to −60 ° C. At this time, the evaporation temperature of the refrigerant changes substantially from about room temperature to about −60 ° C., almost in the same manner as the temperature in the refrigerator. Therefore, even if only one of the compressors is used, it has advantages and disadvantages such as being superior only on the high temperature side or only on the low temperature side, and cannot exhibit the highest refrigeration capacity in the entire range of the evaporation temperature. And as a result,
During the rapid refrigeration process, that is, during the period from the start to the end of freezing, it is difficult to always increase the temperature drop rate, which hinders the improvement of the refrigeration processing capacity.

The present invention has been made in view of such conventional problems, and uses a rapid refrigeration cycle apparatus capable of exhibiting the highest refrigeration capacity over a wide range of evaporation temperatures and improving the refrigeration processing capacity. It is intended to provide a quick freezing method.

[0008]

In order to achieve the above object, an invention according to claim 1 includes a compressor, a condenser, an expansion valve,
In a rapid refrigeration cycle device in which evaporators are sequentially connected in a ring by a refrigerant pipe, a first compressor and a second compressor whose refrigerating capacities are reversed with respect to a predetermined evaporation temperature of a refrigerant are juxtaposed. It is characterized by doing.

According to the above-mentioned invention, the rapid refrigeration cycle apparatus includes the first compressor and the second compressor in which the refrigerating capacity is reversed with respect to a predetermined evaporation temperature of the refrigerant. Therefore, if one of these compressors is applied with a compressor exhibiting a high refrigerating capacity on the high temperature side of the evaporation temperature, and the other is applied with a compressor exhibiting a high refrigerating capacity on the low temperature side. In the rapid refrigeration process, by operating only one of the compressors exhibiting a high refrigerating capacity alone, a high refrigerating capacity can be constantly exhibited at a wide range of evaporation temperatures from a high temperature range to a low temperature range. Therefore, even when the evaporation temperature varies widely as in the case of a batch-type rapid refrigeration apparatus, the highest refrigeration capacity can be exhibited from the start to the completion of refrigeration, and the rate of temperature decrease is the fastest. Can be maintained. In addition, since two compressors can be operated as needed, if the required refrigerating capacity is large and cannot be covered by one compressor, the two refrigerating machines are operated and the refrigerating capacity is generally reduced. It is possible to respond by doubling.

According to a second aspect of the present invention, in the rapid refrigeration cycle apparatus according to the first aspect, the evaporating temperature is detected, and the compressor is operated independently with respect to the compressor having a higher refrigerating capacity at the detected temperature. And an operation controller for switching between the two. According to the above invention, since the operation controller is provided, during the rapid refrigeration process, the evaporating temperature of the refrigerant is detected one by one, and the compressor having the higher refrigeration capacity at the detected temperature is operated to determine the lower one. The operation to stop is performed automatically. Therefore, the switching operation of the single operation of the compressor described above can be reliably performed, and a high refrigeration capacity can be reliably exhibited.

According to a third aspect of the present invention, there is provided the rapid refrigeration cycle apparatus according to the first or second aspect,
The condenser corresponds to the first and second compressors,
The first compressor and the first condenser, and the second compressor and the second condenser are each provided with a condensing unit. It is characterized by doing. According to the above invention,
Since the quick refrigeration cycle apparatus can be configured using a commercially available condensing unit, the number of assembly steps can be reduced. In addition, since a condenser suitable for each characteristic of the first and second compressors can be selected, the compatibility between the compressor and the condenser can be optimized, and the refrigerating capacity can be further improved.

According to a fourth aspect of the present invention, in the rapid refrigeration cycle apparatus according to any one of the first to third aspects, the first compression having a higher refrigerating capacity than the second compressor at a temperature higher than the boundary temperature. It is characterized in that a single-stage compressor is used as the compressor and a two-stage compressor is used as the second compressor that exhibits a higher refrigerating capacity than the first compressor on the low temperature side.

According to the above invention, a single-stage compressor is used as the first compressor exhibiting a high refrigerating capacity on the high temperature side, and a two-stage compressor is used as the second compressor exhibiting a high refrigerating capacity on the low temperature side. Therefore, even if compressors having the same motor output power are used, the refrigerating capacity is reversed at the boundary temperature, and the first compressor is used for high-temperature refrigeration, and the second compressor is used for low-temperature refrigeration. Can be used by specializing each. Therefore,
Since the required power to the operating means for operating the compressor can be made the same, the specifications of power receiving and distribution equipment for supplying power to the operating means can be minimized.

According to a fifth aspect of the present invention, in the rapid refrigeration cycle apparatus according to any one of the first to fourth aspects, an oil separator provided in a refrigerant pipe on a discharge side of the compressor; A reserve tank for storing the lubricating oil separated and recovered by the vessel, a return oil pipe for returning the lubricating oil of the reserve tank to each compressor, and each valve for opening and closing the flow path of each return oil pipe,
An oil level sensor for detecting an oil level in each of the compressors,
A valve controller that controls opening and closing of each of the valves according to each of the oil level.

According to the present invention, the lubricating oil of the compressor mixed into the refrigerant is separated and recovered by the oil separator on the discharge side of the compressor and stored in the reserve tank. Then, each compressor detects an oil level in each crank chamber of the compressor with an oil level sensor provided in each of the compressors, and opens and closes the valves provided in each return oil pipe according to the detected oil level. Adjust the oil level. Therefore, the required amount of lubricating oil can always be held in each crank chamber. Therefore, a problem has arisen in a method in which two compressors are conventionally arranged side by side, and a method in which the crank chambers of the compressors are connected to each other with an oil equalizing pipe or an equalizing pipe to maintain the oil level of the lubricating oil. ,
The problem of oil level fluctuation due to the pressure difference between the crankcases,
As a result, the problem of poor lubrication due to the oil level drop does not occur.

According to a sixth aspect of the present invention, there is provided a compressor, a condenser,
A rapid refrigeration method using a rapid refrigeration cycle device in which an expansion valve and an evaporator are sequentially connected in an annular manner by a refrigerant pipe, wherein a refrigeration capacity is reversed at a predetermined evaporation temperature of a refrigerant. A compressor and a second compressor are provided side by side, and both compressors are operated simultaneously or independently according to a required refrigerating capacity.

According to the above invention, the first compressor or the second compressor can be used in accordance with the refrigerating capacity required in the rapid refrigerating process.
Rapid freezing can be performed by appropriately switching to either one of the compressors alone operation or the simultaneous operation of both compressors. For this reason, of these operations, by switching the single operation, that is, on the high temperature side of the evaporating temperature, only one of the compressors exhibiting a high refrigerating capacity at the temperature is operated alone,
On the low temperature side, by operating only the other compressor that exhibits a high refrigerating capacity at that temperature alone, a high refrigerating capacity can always be exhibited over a wide range of evaporation temperatures from a high temperature range to a low temperature range. Therefore, even when the evaporation temperature varies widely as in the case of a batch type rapid refrigerating apparatus, the highest refrigerating capacity can be exhibited from the start to the end of the refrigerating operation, and the temperature decreasing rate is the fastest. Can be maintained. If the required refrigerating capacity is too large to be covered by a single compressor, both compressors can be operated simultaneously to double the refrigerating capacity.

According to a seventh aspect of the present invention, in the rapid refrigeration method according to the sixth aspect, the evaporating temperature is detected, and only the compressor having a higher refrigerating capacity at the detected temperature is operated alone. I do. According to the above invention, only the compressor having the higher refrigerating capacity at the detected temperature is operated alone, so that the power consumption can be reduced while maintaining the high refrigerating capacity throughout the rapid freezing process.

[0019]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a system diagram of a rapid refrigerating cycle device according to a first embodiment of the present invention, and FIG. 2 is a refrigerating characteristic of a compressor provided in the rapid refrigerating cycle device, ie, a refrigerating capacity versus an evaporating temperature characteristic. It is a graph of. Note that FIG. 1 does not show an operation controller for controlling the operation of the compressor.

As shown in FIG. 1, a rapid refrigeration cycle apparatus 1 according to the present embodiment includes compressors 3, 5,
An oil separator 7 for separating and recovering the compressor lubricating oil mixed in the high-pressure compressed gas-phase refrigerant, an air-cooled condenser 9 for liquefying the high-pressure gas-phase refrigerant from which the lubricating oil has been removed, A liquid reservoir 11 for temporarily storing a refrigerant, a supercooler 13 for cooling the high-pressure liquid-phase refrigerant, an expansion valve 15 for reducing the pressure of the high-pressure liquid-phase refrigerant, and evaporating the depressurized low-pressure liquid-phase refrigerant to remove air in the freezer. The evaporator 17 to be cooled is sequentially connected in a ring shape by a refrigerant pipe shown by a thick solid line. And the compressors 3, 5 are:
A single-stage compressor 3 and a two-stage compressor 5 are arranged side by side,
The operation is controlled by the operation controller, and basically, one of the compressors 3 and 5 compresses the gas-phase refrigerant.

The single-stage compressor 3 has only a low-stage compression mechanism, and the two-stage compressor 5 has a low-stage and high-stage two-stage compression mechanism. The pressure of the accommodated crank chamber is higher in the two-stage compressor 5 than in the single stage 3. In order to protect the compressor, the two-stage compressor 5 is provided with a suction pressure regulating valve (not shown) for lowering the suction pressure to the maximum use pressure when the suction pressure increases. The upper limit of the suction pressure is limited so as not to overload the side compression mechanism.

The nominal output of the motors of these two compressors 3 and 5 is 7.5 kW, and the refrigerating capacity is as shown in FIG.
, Respectively. As described above, both refrigeration capacities are basically two-stage compressor 5
The refrigerating capacity of the compressor increases as the evaporating temperature increases while maintaining a state higher than that of the single-stage compressor 3. However, when the evaporating temperature is −35 ° C. or more, the suction pressure of the two-stage compressor 5 is set to the upper limit. Since the pressure reaches the pressure and the refrigerating capacity becomes constant above the temperature, the refrigerating capacity is reversed by the single-stage compressor 3 at about -31 ° C. That is, the two-stage compressor 5 exhibits a high refrigerating capacity on the low temperature side of the boundary temperature of about −31 ° C., and the single-stage compressor 3 exhibits a high refrigerating capacity on the high temperature side.

Therefore, the compressors 3 and 5 shown in FIG. 1 are operated at the boundary temperature (-31.degree. C.) so as to always exhibit a high refrigerating capacity in the rapid freezing process from normal temperature to -60.degree. Switch and use. That is, only the single-stage compressor 3 is operated on the high-temperature side at the start of refrigeration, and the two-stage compressor 5 is operated and the single-stage compressor 3 is stopped on the low-temperature side. Switch to the machine.

This switching operation control is performed by the operation controller. The operation controller includes a temperature sensor (not shown) provided in the vicinity of the outlet of the evaporator 17 for detecting the temperature of the evaporated refrigerant in real time, and the compressors 3 and 5 which generally operate according to the detected temperature. And a control unit for transmitting a start / stop command to the compressors 3 and 5.

The controller stores the refrigerating characteristics of the compressors 3 and 5, the boundary temperature, and the switching temperature range (see FIG. 2) set over ± α ° C. of the boundary temperature. I have. Then, when the detected temperature falls within the switching temperature range, the compressor that was in a stopped state is operated, and two units are operated within the switching temperature range. The lower compressor is stopped. The reason why the two-unit operation is performed in the switching temperature range is to take into consideration the warm-up state immediately after the start of the compressor that has been in the stopped state. Instead of setting the switching temperature range, each of the compressors 3 and 5 in FIG. 1 is provided with a sensor for detecting whether the operation is in a steady state, and one of the compressors is stopped after the other is in a steady state. You may make it. Further, instead of the temperature, the pressure may be switched by detecting the pressure on the outlet side of the evaporator or the suction pressure of the compressor at which the refrigerant is saturated vapor.

According to the rapid refrigeration cycle apparatus 1 having the above configuration, at the start of refrigeration where the evaporation temperature is high, the single-stage compressor 3 which exhibits a high refrigeration capacity on the high temperature side of the boundary temperature (-31 ° C.) operates. Then, the cooling rate can be increased in the high temperature range, and when the evaporating temperature falls within the switching temperature range, the two-stage compressor 5 exhibiting a high refrigerating capacity on the low temperature side is operated to operate the two units. When the evaporating temperature is cooled to reach the lower limit of the switching temperature range, the single-stage compressor 3 is stopped, and the two-stage compressor 5 can increase the cooling rate even in a low temperature range. . Therefore,
Since the cooling rate can be increased over the entire range from the start to the end of freezing, the time required for the freezing process can be significantly reduced,
In particular, the refrigerating capacity of the batch type rapid refrigerating apparatus can be remarkably improved.

A check valve or a similar structure (not shown) is provided at a discharge port of each of the compressors 3 and 5, and a high-pressure gas-phase refrigerant discharged from one of the compressors in an operating state is provided. In addition, it is prevented from flowing back into the other stopped compressor via the refrigerant pipe.

The lubricating oil separated and recovered from the high-pressure refrigerant in the oil separator 7 is returned to the crank chambers of the compressors 3 and 5, and is again used for lubricating sliding portions in the compressors 3 and 5. You. Then, the process of being discharged together with the high-pressure refrigerant from the compressors 3 and 5 and separated and recovered by the oil separator 7 is repeated. If an appropriate amount of such lubricating oil is not always maintained in the crank chamber, poor lubrication of the compressor sliding portion will occur. The height of the lubricating oil in each of the crank chambers is adjusted to prevent the oil level.

The oil level controller 19 includes a reserve tank 21 for storing the lubricating oil collected by the oil separator 7, and a single-stage compressor 3 and a two-stage compressor 5 from the reserve tank 21.
Return oil pipes 23 and 25 respectively connected to the crank chambers of
An electromagnetic valve 27 for opening and closing the flow paths of the oil return pipes 23 and 25, optical sensors 33 and 35 as liquid level sensors for detecting the respective oil level in the crank chamber, and according to the respective oil level. Valve controller for operating the electromagnetic valve 27 (not shown)
Consists of

When the oil level falls below the lower limit set for each of the compressors 3 and 5, the light sensors 33 and 35 detect this, and the valve controller responds to the detection signal. By operating the solenoid valve 27, the flow path of the corresponding oil return pipes 23 and 25 is opened to supply the lubricating oil to the reserve tank 21.
To the crank chambers of the compressors 3 and 5, when the upper limit is reached, the flow path is closed and the supply is stopped. Therefore, the required amount of lubricating oil can always be reliably held in the crank chambers of the compressors 3 and 5. Therefore,
Conventionally, when two compressors are juxtaposed, a problem has occurred in a method of connecting the respective crank chambers with oil equalizing pipes or equalizing pipes to maintain the oil level, The problem of oil level fluctuation due to the pressure difference can be prevented.

FIG. 3 is a system diagram of a rapid refrigeration cycle apparatus 2 according to a second embodiment of the present invention. In the first embodiment, the oil separator, the air-cooled condenser, and the liquid reservoir are:
In the second embodiment, the oil separators 7a and 7b and the air-cooled condenser 9 are shared by the single-stage compressor and the two-stage compressor.
a, 9b and liquid reservoirs 11a, 11b are provided corresponding to the two compressors 3, 5 and connected in series with each other, each constituting a so-called condensing unit 4a, 4b. Is different.

According to this configuration, since the condensing units 4a and 4b are commercially available in an assembled state, the compressors 3 and 5, the oil separators 7a and 7b, and the air-cooled condenser 9
a, 9b and the liquid reservoirs 11a, 11b can be omitted, and the total assembly man-hours of the quick refrigeration cycle apparatus 2 can be reduced. In addition, since dedicated air-cooled condensers 9a and 9b and other devices that match the characteristics of the single-stage compressor 3 and the two-stage compressor 5, respectively, can be selected, the compressors 3, 5
And the compatibility with the air-cooled condensers 9a and 9b and other devices can be optimized.

The oil level controller 19 has two oil separators 7a and 7b, so that both oil separators 7a and 7b are used.
a, a pipe 22 connecting the 7b and the reserve tank 21
a and 22b are provided, respectively, which is different from the first embodiment in this point, but the rest is the same as the above-described configuration.

Although the embodiment according to the present invention has been described above, the present invention is not limited to the embodiment, and the following modifications can be made without departing from the gist thereof. (A) In the present embodiment, the rapid refrigeration cycle apparatus is applied to a batch-type rapid refrigeration apparatus. However, a continuous rapid refrigeration apparatus, that is, a freezing object placed on a conveyor has an entrance and an exit. It goes without saying that the present invention is also applicable to a rapid freezing apparatus that freezes while moving in a freezer. In addition, in the case of this apparatus, the temperature in the refrigerator is kept relatively constant as compared with the batch type, so that the fluctuation of the evaporation temperature is small, but the heat content of each refrigeration object carried into the refrigerator is reduced. Due to the fluctuation, the heat load of the rapid refrigeration cycle apparatus fluctuates and the evaporation temperature fluctuates. At this time, if the rapid refrigeration cycle device is used, the compressor having a high refrigerating capacity is selectively operated in accordance with the fluctuation of the evaporating temperature, so that the fluctuation of the refrigerating processing capacity due to the fluctuation of the heat load can be suppressed. .

(B) In this embodiment, as the liquid level sensor, an optical sensor that detects the liquid level by measuring the distance from a predetermined reference position to the liquid level is used. In addition, an ultrasonic sensor that detects the oil level at the measurement distance to the liquid level, a float switch that detects the vertical fluctuation of the liquid level by moving the float up and down, and the like are also applicable.

(C) In the present embodiment, the single-stage compressor and the two-stage compressor are generally selectively operated, but the power capacity of the power receiving and distribution equipment for supplying power to these compressors is always two. If it is set to a specification that allows the unit to be operated, both the single-stage compressor and the two-stage compressor are operated steadily, or the two units are locally operated only in a predetermined evaporation temperature range in which the refrigeration capacity is to be increased. You can also. As an example of the latter, as shown in FIG. 2, the compressor is selectively operated from a room temperature to a predetermined temperature, for example, from -45 ° C. One example is to restart the stopped single-stage compressor to operate two units.
According to such an operation method, the refrigerating capacity is significantly reduced, so that the refrigerating capacity can be locally doubled on the low temperature side where the increase in the refrigerating capacity is desired, and the power consumption is always smaller than in the two-unit operation. It becomes significantly smaller.

[0037]

As described above, according to the first aspect of the present invention, the highest refrigeration capacity can be exhibited from the start to the end of refrigeration during rapid freezing, and the temperature decreasing rate is maintained at the highest speed. As a result, the refrigerating capacity of the batch type rapid refrigerating apparatus can be significantly improved. In addition, since it is possible to double the refrigeration capacity by operating two units,
Excellent refrigerating capacity.

According to the second aspect of the present invention, a high refrigeration capacity can be reliably exhibited, so that the refrigeration processing capacity can be reliably improved.

According to the third aspect of the present invention, the number of assembling steps can be reduced, so that the manufacturing period and the manufacturing cost can be reduced. Further, since the compatibility between the compressor and the condenser can be optimized and the refrigerating capacity can be further increased, the refrigerating processing capacity can be further improved.

According to the fourth aspect of the invention, the specifications of the power receiving and distribution equipment for supplying the operating power of the compressor can be minimized, so that the manufacturing cost can be reduced.

According to the fifth aspect of the invention, the required amount of lubricating oil can always be ensured in the compressor, so that emergency stop of the compressor due to lack of oil can be prevented, and the rapid refrigerating apparatus can be operated stably.

According to the sixth aspect of the present invention, the highest refrigeration capacity can be exhibited from the start to the completion of refrigeration during rapid refrigeration and the temperature can be maintained at the highest rate. The refrigeration processing capacity of the refrigeration system can be significantly improved. In addition, since the refrigeration capacity can be almost doubled by operating two units, the degree of freedom of the refrigeration capacity is excellent.

According to the present invention, the power consumption can be suppressed low, and the running cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a system diagram of a rapid refrigeration cycle apparatus according to a first embodiment of the present invention.

FIG. 2 is a graph showing a refrigerating capacity, which is a refrigerating property of a compressor provided to the rapid refrigerating cycle apparatus, versus an evaporating temperature characteristic.

FIG. 3 is a system diagram of a rapid refrigeration cycle device according to a second embodiment of the present invention.

[Explanation of symbols]

 1, 2 rapid refrigerating cycle device 3 single-stage compressor (first compressor) 5 two-stage compressor (second compressor) 7, 7a, 7b oil separator 9, 9a, 9b air-cooled condenser (condenser) 11 , 11a, 11b Liquid reservoir 13 Subcooler 15 Expansion valve 17 Evaporator 19 Liquid level controller 21 Reserve tank 23, 25 Oil return pipe 27 Solenoid valve (valve) 33, 35 Optical sensor (liquid level sensor)

Claims (7)

[Claims] 1. A rapid refrigeration cycle apparatus comprising a compressor, a condenser, an expansion valve, and an evaporator sequentially connected in an annular manner by a refrigerant pipe. A rapid refrigeration cycle apparatus comprising: a first compressor and a second compressor. 2. An operation controller for detecting the evaporation temperature and switching an operation to an independent operation of a compressor having a higher refrigerating capacity at the detected temperature.
2. The rapid refrigerating cycle device according to item 1. 3. The condenser according to claim 1, wherein the condenser includes first and second condensers connected in series and arranged in parallel with the first and second compressors, respectively. 1 condenser,
3. The rapid refrigeration cycle apparatus according to claim 1, wherein the second compressor and the second condenser each constitute a condensing unit. 4. A single-stage compressor as a first compressor exhibiting a higher refrigerating capacity than the second compressor at a temperature higher than the boundary temperature, and exhibiting a higher refrigerating capacity than the first compressor at a low temperature side. The rapid refrigeration cycle apparatus according to any one of claims 1 to 3, wherein a two-stage compressor is used as the second compressor. 5. An oil separator provided in a refrigerant pipe on a discharge side of the compressor, a reserve tank for storing lubricating oil separated and recovered by the oil separator, and a lubricating oil in the reserve tank. A return oil pipe that returns to each compressor, each valve that opens and closes the flow path of each return oil pipe, an oil level sensor that detects the oil level in each of the compressors, and according to each oil level The rapid refrigeration cycle apparatus according to any one of claims 1 to 4, further comprising a valve controller that controls opening and closing of each of the valves. 6. A rapid refrigeration method using a rapid refrigeration cycle device in which a compressor, a condenser, an expansion valve, and an evaporator are sequentially connected in a ring through a refrigerant line, wherein a predetermined evaporation temperature of the refrigerant is provided. The first compressor and the second compressor whose refrigerating capacity is reversed to each other are provided side by side, and both compressors are operated simultaneously or independently according to the required refrigerating capacity. Quick freezing method. 7. The rapid refrigerating method according to claim 6, wherein the evaporating temperature is detected, and only the compressor having a higher refrigerating capacity at the detected temperature is operated alone.