JPS6257910B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the configuration of a cold air forced circulation type refrigeration system such as an open-shod case, and particularly to a cooling device that prevents frost from forming on the circulating air inlet side of the cooler, obstructing the circulation of cold air, or preventing defrosting operation. This prevents it from happening frequently.

As shown in FIG. 1, a conventional refrigeration system of this type has a peripheral wall 1 as a heat insulating wall, a storage chamber 2 which is open at the front, and a section of which is omitted at a distance from the peripheral wall 1 within the storage chamber 2. There is an open case 5 in which a U-shaped partition plate 3 is arranged and a cold air flow passage 4 is formed between the peripheral wall 1 and the partition plate 3. A cooler 11 is installed, which forms a refrigerant cycle together with a compressor 6, a condenser 8, a liquid receiver 9, an expansion valve 10, etc., which are forcedly air-cooled by a compressor 6 and a fan 7. The cooler 11 cools the air that is accelerated by a blower 14 that forms an air curtain between the outlet 12 and the suction port 13 formed at the bottom of the opening and flows through the cold air flow path 4 . In such a configuration, moisture in the circulating air concentrates on the front suction side of the cooler 11, forms dehumidifying frost, and freezes, reducing cooling efficiency and inhibiting cold air circulation, making it impossible to form an air curtain sufficiently. The cooling inside the storage room was getting worse.

The present invention has been made in view of the above points,
Below, FIGS. 2 and 3 will be explained.

A refrigeration device main body 25 includes a partition plate 23 that forms a cold air flow passage 22 between a heat insulating peripheral wall 21 and a storage chamber 24, similar to the open storage case 5 and the like.
As shown by the arrow in FIG. 2, the blower 26
Cooler 2 that accelerates circulating air and has multiple stages such as two stages front and rear.
7 and 28 to form an air curtain or to cool the inside of the storage chamber 24, etc.

29 is a refrigerant compressor, the discharge side of which is connected via a pipe body 30 to a condenser 32 which is forcedly air-cooled by a blower 31; connected to the valve 35 and further connected to the expansion valve 3
5 is connected to the inflow side of the pre-cooler 27 of the coolers 27 and 28 via a pipe 36. A pipe body 37 on the outflow side of this pre-cooler 27 opens into a gas-liquid separator 38 . Said cooler 27, 28
Of these, the post-cooler 28 has a pipe body 39 on the inflow side opened in the gas-liquid separator 38 so as to be immersed in the liquid refrigerant 40, and a pipe body 41 on the outflow side communicates with an ejector 42 disposed at an appropriate location. It is connected. The latter stage cooler 28 is provided with an evaporation pressure regulating valve 43 consisting of a pressure reducing mechanism such as an orifice nozzle or a variable valve device at a suitable position in the pipe body 39 on the inflow side, and adjusts the liquid refrigerant 40 from the gas-liquid separator 38 to a predetermined pressure. It flows in and evaporates.
The ejector 42 has a nozzle part communicating with the gas-liquid separator 38 through a pipe body 44 facing upward away from the liquid refrigerant 40, and a discharge part communicating with the pipe body 45.
It communicates with the suction side of the refrigerant compressor 29 via. The expansion valve 35 detects the temperature of the refrigerant discharged from the post-cooler 28 with a temperature sensing section 46 via a tube body 41 etc., and controls the degree of opening and closing thereof. 47 is a conduit that guides the evaporation pressure of the refrigerant from the pipe body 41 to the expansion valve 35.

To explain the operation of the above configuration, the refrigerant discharged from the refrigerant compressor 29 and condensed in the condenser 32 is depressurized by the expansion valve 35 and then transferred to the pre-cooler 27.
Evaporates at At this time, to prevent the refrigerant evaporation temperature in the pre-cooler 27 from becoming too low, for example, 0°C to -5°C.
The expansion valve 35 is adjusted in advance so that the temperature is around ℃.
This is to maintain the temperature of the outer surface near the freezing point temperature in order to prevent moisture condensed on the outer surface of the pre-cooler 27 from freezing. This is the front cooler 2
When the gas refrigerant flows directly from 7 to the second stage cooler 28, the amount of gas refrigerant increases, and the heat exchange capacity of the second stage cooler 28 becomes smaller, so that the evaporation temperature is sufficient to cool the inside of the refrigerator, for example, around -10°C to -15°C. Although a liquid refrigerant having an evaporation temperature of The air circulating through the flow path 22 is cooled to a predetermined temperature.

The gas-liquid mixed refrigerant discharged from the pre-cooler 27 is separated in the gas-liquid separator 38, and the gas refrigerant is transferred to the pipe body 4.
4, the return refrigerant flowing out from the post-cooler 28 and flowing into the ejector 42 is sucked, and is returned to the refrigerant compressor 29 together with the return refrigerant.

3 is a Mollier diagram showing the operation of the refrigerant by the apparatus of the present invention shown in FIG. 2, where point A is the refrigerant compressor 29.
point B is the inlet of the expansion valve 35, point C is also the outlet, point D is the outlet of the front cooler 27, point E is the inlet of the rear cooler 28, point F is the same outlet, and point G is the refrigerant. The inlet of the compressor 29, point H, is the nozzle inlet of the ejector 42. The change in the state of the refrigerant at point H and the refrigerant at point F in the ejector 42 is small and can be roughly represented by a single point indicated by point G, since the mixing ratio determined by the state at point D is large. In the experiment, the open storage case that keeps the inside of the storage room 24 at around 0°C has P ₁
The saturation temperature of the refrigerant corresponding to P 2 is approximately 0℃ to -5℃, and the saturation temperature corresponding to P ₂ is -10℃ to -15℃.
It was hot. With the above-described configuration of the present invention, the moisture in the air flowing through the front cooler 27 is removed by adhering to the front cooler 27, and the amount of moisture in the air reaching the rear cooler 28 is reduced. Therefore, there is little frost formation on the rear cooler 28, and cold air circulation is not inhibited by so-called clogging caused by frost. Therefore, the interval between defrosting operations becomes longer, and it is possible to improve the cooling efficiency and the capacity of the cooler. Moreover, the front cooler 2
Since the evaporation temperature of 7 is high, most of the attached moisture does not turn into frost, but becomes water droplets, which naturally flow down and are removed, causing clogging in this pre-cooler 27.
There is almost no need for special configurations such as frequent heating and defrosting of dehumidifying coolers, which was required in the past, and even if some frost forms, most of it is melted by the circulating air, so even if it is not necessary, Even if there is one, it can be extremely simple and of small capacity. Furthermore, the dehumidifying cooler becomes frosted and freezes, which narrows the cold air flow passage when viewed from the perspective of the cold air flow passage as a whole.The conventional disadvantages could hardly be eliminated and the cold air circulation was obstructed, but the present invention overcomes these drawbacks. Can be largely removed.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the conventional device, FIG. 2 is a schematic diagram of the main part of the device of the present invention, and FIG. 3 is a Mollier diagram. 27... Pre-stage cooler, 28... Post-stage cooler, 3
8... Gas-liquid separator.

Claims (1)

[Claims] 1 A plurality of stages of coolers for cooling the circulating air are arranged in an appropriately formed cold air flow passage, and the evaporation temperature in the first stage of these coolers is made to be near the freezing point temperature, and the first stage cooler A cold air forced cooling device characterized in that the outflow side tube of the second stage cooler is opened into the gas-liquid separator, and the inflow side tube of the second-stage cooler is immersed and opened in the liquid refrigerant in the gas-liquid separator. Circulating refrigeration equipment.