JPS6238626B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a refrigeration system, and in particular has two or more chambers with different temperatures, such as a freezing chamber and a refrigerator chamber, and each of these chambers is cooled independently. The present invention relates to a refrigeration device such as a refrigerator.

Generally, in a refrigerator that has a freezer compartment and a refrigerator compartment that need to be cooled to different temperatures as described above, in order to cool each of the compartments separately, each compartment is equipped with a dedicated freezer compartment evaporator or refrigerator. is equipped with an evaporator for the refrigerator compartment, and controls the flow of refrigerant to both of the evaporators or only one of them by opening and closing a solenoid valve installed in the piping connecting them. There is.

However, such devices require valve devices with mechanically movable parts, such as solenoid valves, and since these valve devices are buried in the insulation wall, maintenance and inspection are difficult once they are assembled. However, there are problems in that the lifespan and reliability of the refrigerator are not necessarily sufficient, and the structure is expensive.

Recently, refrigerators have been proposed that have no mechanically moving parts, have a simple structure, and use bubble pumps that act as valves on the flow of refrigerant.

The present invention provides a refrigeration system in which the refrigerant is switched using the bubble pump, and the refrigerant is reliably switched and reliably prevented from leaking into the evaporator when the refrigerant is not in operation. The purpose is to provide

Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 denotes a compressor, and the high-temperature gas of the refrigerant compressed by the compressor 1 is condensed in a condenser 2 and stored in a liquid tank 4 through a pressure regulator 3 consisting of a capillary tube and the like. .

In the liquid tank 4, as shown in FIG. 3, one end of a U-shaped conduit 5 penetrates the bottom wall and protrudes to an appropriate height, and the other end of the U-shaped conduit 5 is connected to an accumulator. It is opened at the bottom of 6. The accumulator 6 is further equipped with a conduit 7 that penetrates its bottom wall and opens at a predetermined height, and the conduit 7 is connected to a refrigerator compartment evaporator 9 via a pressure regulator 8 such as a capillary tube. (Figure 1). A freezer compartment evaporator 11 is further connected to the refrigerator compartment evaporator 9 via a connecting pipe 10, and this freezer compartment evaporator 11 is connected to the compressor 1.
One closed cycle connected to the suction side of the

One end of yet another U-shaped conduit 12 is opened at the bottom of the liquid tank 4, and the vertically rising portion 12a at the other end of the U-shaped conduit 12 is connected to the accumulator 6. It extends above the top end of the conduit 7 , where it is bent into an inverted U shape and connected to the conduit 14 via a pipe joint 13 . A pressure regulator 15 such as a capillary tube is provided in the middle of the conduit 14, and the conduit 14 is in the middle of a connecting pipe 10 that connects the evaporator 9 for the refrigerator compartment and the evaporator 11 for the freezer compartment. It is connected to the.

By the way, the pipe joint 13 of the U-shaped conduit 12
A bubble pump heater 16 is wound around the lower outer periphery of the side vertically rising portion 12a, and the accumulator 6 and pipe joint 13 are connected to the liquid tank 4 via pressure equalizing pipes 17 and 18, respectively.

FIG. 2 is an electrical control circuit diagram of the above device,
When the defrost switch 20 is in contact with the contact a side and the freezer compartment control switch 21 is in the ON state, the compressor 1 is driven, and when the temperature of the refrigerator compartment falls below a predetermined temperature and the refrigerator compartment control switch 22 is in the ON state. The bubble pump heater 16, connecting pipe heater 23, and gutter heater 24 are energized, the freezer compartment is cooled to a predetermined temperature, and the freezer compartment control switch 21 is activated.
When turned off, the drive of the compressor 1 is stopped.
Further, when the defrosting switch 20 is switched to the contact b side, the defrosting heater 25 and the defrosting heat-sensitive tube heater 26 are energized in exactly the same way as in a conventional refrigerator. In the figure, reference numeral 27 is a defrost detection bimetal, 28 is a door switch, 29 is an interior light, 30 is a drain heater, 3
1 is a freezer compartment control switch heater, and 32 is a fuse.

If both the refrigerator compartment and the freezer compartment do not reach their respective predetermined temperatures but exceed the predetermined temperatures, the freezer compartment control switch 21 is turned on and the refrigerator compartment control switch 22 is turned off. Therefore, the compressor 1 is driven with the bubble pump heater 16 in the OFF state. When the compressor is driven in this manner, the refrigerant that is compressed by the compressor and then condensed by the condenser 2 is stored in the liquid tank 4. When liquid refrigerant accumulates in the liquid tank 4 and its liquid level rises, the liquid refrigerant passes through the U-shaped conduit 5 and reaches the accumulator 6.
further flows into the refrigerator compartment evaporator 9 and the freezer compartment evaporator 11 via a conduit 7 and a pressure regulator 8.
The evaporators 9 and 11 cool the refrigerator compartment and the freezer compartment, respectively.

In this state, the other U-shaped conduit 12
Although the liquid refrigerant flows into the pressure equalizing pipe 1, the liquid tank 4, the accumulator 6, and the pipe joint 13 each
7 and 18, and the liquid levels in the liquid tank 4, accumulator 6, and U-shaped conduit 12 are the same, and the top of the vertically rising portion 12a of the U-shaped conduit 12 is Since it extends above the opening of the conduit 7 in the accumulator 6, liquid refrigerant does not flow into the conduit 14 through the pipe joint 13 (FIG. 3).

Here, when the refrigerator compartment is cooled to the specified temperature,
The refrigerator compartment control switch 22 is switched to the ON side, and the bubble pump heater 16 is energized. When the bubble pump heater 16 is energized and the riser pipe part 12a is heated, the liquid refrigerant inside the riser pipe part 12a boils and bubbles made of refrigerant vapor are generated, and the liquid refrigerant is pushed up by the pumping action of the bubbles. (Fig. 4), overflows from the top of the riser pipe section 12a into the pipe joint 13, and the overflowing liquid refrigerant flows into the conduit 1.
4. It flows into the freezer compartment evaporator 11 via the pressure regulator 15, and the cooling effect of the freezer compartment is performed.

On the other hand, at this time, the liquid refrigerant in the liquid tank 4 flows to the freezer compartment evaporator 11 side due to the bubble pump action, so the liquid level in the liquid tank 4 decreases and the flow of the liquid refrigerant to the accumulator 6 side is stopped. , the liquid refrigerant does not flow to the refrigerator compartment evaporator 9, and cooling of the refrigerator compartment is interrupted.

Thereafter, the drive of the compressor 1 is repeatedly stopped depending on the rise and fall of the temperature in the freezer compartment, and if the temperature in the refrigerator compartment exceeds a predetermined level during that time, the refrigerator compartment control switch 2 is activated.
2 is switched to the OFF side, the operation of the bubble pump is stopped, and as described above, the liquid refrigerant passes through the accumulator 6 and sequentially flows through the refrigeration evaporator and the freezing evaporator to cool both chambers.

By the way, as mentioned above, the bubble pump heater 16
When electricity is applied to the heater, a part of the liquid refrigerant is heated and gasified, and as this gas (bubbles) floats, the liquid refrigerant is sandwiched between the bubbles due to surface tension and floats simultaneously. , the liquid refrigerant is eventually pumped up.

However, as shown in FIG. 5, if the inner radius of curvature of the inverted U-shaped portion formed at the top end of the vertical riser 12a constituting the bubble pump is large, the bubbles will form a flattened upper surface near the apex of the bend. A portion of the liquid refrigerant that has been lifted up by the bubbles is unable to travel through the curved portion of the pipe and flows back. Therefore, there are disadvantages such as a decrease in pump efficiency and the inability to pump up a required amount of liquid refrigerant.

Therefore, as a result of measuring the radius of curvature at which the backflow of the refrigerant occurs by using pipes with various inner diameters and varying the inner radius of curvature R of the bent part, the relationship between the inner diameter D of the pipe at the point of occurrence of the backflow and the radius of curvature R was determined. It turns out that is as shown in FIG. 7, and the relationship is expressed as R=-10.34×ln(0.056×D-0.112)...(1). Therefore, the radius of curvature of the bent portion may be set to a value smaller than R calculated by the above formula for each D.

On the other hand, if the diameter of the riser pipe is made smaller, the inner diameter
If the thickness was less than 2.5 mm, the refrigeration system could not function properly. This seems to be because a tube with an inner diameter of 2.5 mm or less is too small and the tube resistance is large enough that the liquid does not rise sufficiently. Therefore, the internal diameter D of the riser is 2.5
It must be larger than mm. However, if the radius of curvature of the bent portion at the top end of the riser pipe is made equal to or less than the value calculated using equation (1) above, the air bubbles near the top end will hardly expand into a flat shape, as shown in Figure 6. In this process, the liquid refrigerant lifted up by the bubbles moves through the bend while being sandwiched between the bubbles, and most of it is moved downstream, ensuring that the desired amount of liquid refrigerant is always delivered at a predetermined level. can be transferred to the evaporator side.

As explained above, in the present invention, the inner radius of curvature of the inverted U-shaped portion formed at the top of the riser pipe constituting the bubble pump is set to be equal to or less than the value calculated by the above formula (1), so that the air bubbles can be lifted up. It is possible to almost prevent the backflow phenomenon of liquid refrigerant, improve pump efficiency, and supply sufficient refrigerant to a given evaporator without the need to use a high-output heater and increase power consumption. This brings about effects such as being able to maintain sufficient cooling efficiency of the evaporator.

[Brief explanation of the drawing]

FIG. 1 is a refrigeration cycle diagram of the refrigeration system of the present invention,
Figure 2 is the electrical control circuit diagram, Figures 3 and 4.
The figures are enlarged views of the bubble pump components, FIG. 3 is an explanatory diagram showing when the bubble pump is not working, FIG. 4 is an explanatory diagram showing when the bubble pump is working, and FIGS. FIG. 7 is a diagram showing the relationship between the pipe inner diameter and the radius of curvature at the point where the refrigerant backflow occurs. 1...Compressor, 2...Condenser, 4...Liquid tank, 6...Accumulator, 8, 15...Pressure regulator, 9...Evaporator for refrigerator compartment, 11...Evaporator for freezer compartment, 16...Bubble pump heater, 17, 18...Pressure equalization pipe.

Claims (1)

[Scope of Claims] 1. A system having a plurality of evaporators, in which the liquid refrigerant discharged by a compressor is controlled to turn on and off of a bubble pump to a part of the evaporators among the plurality of evaporators. In a refrigeration system that supplies water to or bypasses the air bubble pump, the top end of the riser tube constituting the bubble pump is bent into an inverted U shape, and the inner radius of curvature R of the bent portion is set to the riser. A refrigeration system characterized in that the inner diameter D of the tube is set to be less than or equal to the value calculated by the following formula: R = -10.34 x ln (0.056 x D - 0.112) (here, D≧2.5).