JPH0680376B2 - Dual refrigeration system - Google Patents

Description

TECHNICAL FIELD The present invention relates to a refrigerating apparatus capable of continuously supplying ultra-low temperature air of about −70 ° C.

(Prior Art) As a conventional device for supplying ultra-low temperature air, in a device having a refrigeration cycle composed of a compressor, a condenser, a capillary tube, an evaporator, etc., outside air is directly introduced into the evaporator for cooling. There is a system that supplies the generated air.

Further, as shown in FIG. 2, compressors 21, 31, 41, condensers 22, 3
In a device having two high temperature and one low temperature refrigeration cycle consisting of 2,42, expansion valves 23,33,43 and evaporators 24,34,44, one evaporator 24 of the high temperature refrigeration cycle and condensation of the low temperature refrigeration cycle Configure a cascade capacitor with the device 32,
A method of supplying the cooling air to the condenser 32 and further cooling the air dehumidified and cooled by the evaporator 44 of the other high temperature refrigeration cycle to -70 ° C. by the evaporator 34 of the low temperature refrigeration cycle and then supplying the cooling air. is there.

(Problems to be Solved by the Invention) However, in such a conventional device, since the method of directly contacting the outside air with the fins of the evaporator is adopted,
Although it is good at the time of starting the operation, frost may adhere to the fins of the evaporator within a short time after the start of the operation, and the fins may be clogged, resulting in a significant decrease in the cooling capacity. Therefore, in order to recover the cooling capacity, the refrigerator had to be temporarily stopped and defrosted. Then, there is an inconvenience that the supply of the cooling air must be temporarily interrupted as the refrigerator is stopped.

Also in the case of the conventional example shown in FIG. 2, the outside air is once pre-cooled by using the evaporator of the high temperature side refrigeration cycle. However, since three compressors are used, the power consumption is low. There is a disadvantage that the number of devices increases and the space of the device increases.

Therefore, an object of the present invention is to provide a device that continuously supplies cooling air without stopping the refrigerator for a long time and consumes less power, in order to solve the drawbacks of the conventional technique.

(Means for Solving the Problem) That is, the present invention comprises a precooler, a main cooler supplied with air produced by the precooler, and a cascade condenser, and a compressor and a condenser are provided in the main cooler. An evaporator of a low temperature side refrigeration cycle is installed in circulation connection with a pressure reducing means and an evaporator, and a circulation connection is made with a compressor, a condenser, a pressure reducing means and two evaporators 4 and 8 connected in parallel in the cascade condenser. One evaporator 8 of the high temperature side refrigeration cycle
This object is achieved by a binary refrigeration system in which 11 and 11 are installed, and the other evaporator 4 of the high temperature side refrigeration cycle is installed in the precooler.

(Operation) In the apparatus according to the present invention, first, the air introduced from the outside in the precooler is dehumidified and cooled to a temperature of 1 to 5 ° C. Dehumidified and cooled air is supplied to the main cooler,
There, it is made into ultra-low temperature air.

The evaporator of the low temperature side refrigeration cycle installed in the main cooler is configured such that the evaporator of the high temperature side refrigeration cycle and the condenser of the low temperature side refrigeration cycle exchange heat via a cascade condenser. Due to the relationship, the state of high cooling efficiency is maintained. As described above, the main cooler according to the present invention produces ultra-low temperature air by the dehumidifying cooling by the precooler and the condenser cooling function of the low temperature side refrigeration cycle by the cascade condenser.

(Example) The present invention will be described in detail below with reference to the example shown in FIG.

In the figure, A is a refrigeration cycle on the high temperature side, which constitutes a refrigeration cycle with a compressor 1, a condenser 2, a capillary tube 3, an evaporator 4 and an evaporation pressure adjusting valve 6 (EPR), and further comprises a capillary tube 3, an evaporation A capillary tube 7 and an evaporator 8 are connected in parallel with the evaporator 4 and the evaporation pressure adjusting valve 6.

Further, B is a refrigeration cycle on the low temperature side, and the refrigeration cycle is constituted by the compressor 10, the condenser 11, the capillary tube 12 and the evaporator 13.

The evaporator 8 of the refrigeration cycle A on the high temperature side and the condenser 11 of the refrigeration cycle B on the low temperature side constitute a cascade condenser 9 so that heat can be exchanged with each other.

Although not shown in the drawing, the precooler 5 cooled by the evaporator 4 of the refrigeration cycle A on the high temperature side and the main cooler 14 cooled by the evaporator 13 of the refrigeration cycle B on the low temperature side are in communication with each other. The air that has been dehumidified and cooled by the precooler 5 is supplied to the main cooler 14 by means such as a fan.
It is designed to flow to.

In the embodiment according to the present invention having the above-described configuration, first, in the refrigeration cycle A on the high temperature side, the precooler 5 is used.
The air introduced from the outside is dehumidified and cooled to a temperature of about 1 to 5 ° C.

The dehumidified and cooled air is further cooled by the evaporator 13 in the main cooler 14 constituting the refrigeration cycle B on the low temperature side, reaches a temperature of about −70 ° C., and is continuously and stably supplied to necessary locations. It Meanwhile, in the main cooler 14, since the air that has been dehumidified and cooled in the precooler 5 is sent in advance, it is difficult for frost to adhere to the fins and the like of the evaporator 13.

Further, the condenser 11 of the refrigeration cycle B on the low temperature side heats when the refrigerant is condensed, but the cascade condenser 9 exchanges heat with the evaporator 8 of the refrigeration cycle A on the high temperature side. A decrease in cooling capacity due to heating of the condenser 11 is unlikely to occur.

Further, in the device according to the present invention, since the evaporation pressure adjusting valve 6 is provided immediately after the evaporator 4 which constitutes the precooler 5, for example, if the evaporation temperature is set to 0 ° C. or higher, good dehumidifying and cooling can always be performed. There is no need to worry that the water droplets that have condensed on the surface of the fins of the evaporator 4 freeze and clog the evaporator 4 and hinder the air flow.

(Effect) In the conventional device, continuous operation could be performed for at most about two and a half hours due to frost formation. However, in the case of the present invention,
It is possible to operate continuously for 10 hours or more because it is cooled to ultra-low temperature after being preliminarily dehumidified and cooled.

In addition, the power consumption is smaller than that of the conventional device.

Furthermore, since the number of compressors is two, it is possible to save space.

[Brief description of drawings]

FIG. 1 is a schematic view of an apparatus showing an embodiment according to the present invention, and FIG. 2 is a schematic view of an apparatus showing a prior art. A: High temperature side refrigeration cycle B: Low temperature side refrigeration cycle 1,10 ... Compressor, 2,11 ... Condenser 3,7,12 ... Capillary tube 5 ... Precooler, 6 ... Evaporation pressure Regulator valves 4,8,13 …… Evaporator 9 …… Cascade condenser, 14 …… Main cooler

Claims (1)

[Claims] 1. A precooler in which a compressor, a condenser, a decompression means, and one evaporator of a high temperature side refrigeration cycle circulated and connected to two evaporators 4 and 8 connected in parallel, and the precooler are installed. A main cooler provided with a compressor, a condenser, a pressure reducing means, and an evaporator of a low-temperature side refrigeration cycle, which are circulated and connected to the evaporator, and the other evaporator of the high-temperature side refrigeration cycle. And a condenser for the low temperature side refrigeration cycle and a cascade condenser in which the high temperature side refrigeration cycle and the low temperature side refrigeration cycle are used at the same time, and the refrigerant is constantly supplied to the two evaporators of the high temperature side refrigeration cycle. A dual refrigeration system characterized in that