JPS5822862A - Decompression device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vapor compression type refrigeration cycle that utilizes the latent heat of a refrigerant, and particularly to control of the refrigerant flow rate using a pressure reducing device.

Part tv! J shows an example of a conventional refrigeration cycle.
In the figure, (1) is the compressor, (2) is the condenser, and (3)
is a pressure reducing device, (4J is an evaporator, (6) is a heat exchanger, (6
) are suction pipes, which are connected in sequence to form a refrigeration cycle.

FIG. 2 is a diagram showing the structure of the pressure reducing device (3).
7] is a tube, and (8) is an insert having a spiral groove (8&) on the outer periphery and tightly fitted into the tube (7).

In such a conventional refrigeration cycle, during stable operation, the refrigerant gas that has become high temperature and high pressure in the compressor (11) is cooled and liquefied in the condenser (2), and the heat is exchanged with the suction pipe (6). After the refrigeration effect (utilization) is increased by the exchanger (5), it passes through the groove (8&) of the pressure reducing device (3) to become low temperature and low pressure, and is led to the evaporator (4). 4) When the refrigerant liquid is gasified, it absorbs heat from the surroundings and generates refrigeration. After this, the refrigerant gas exchanges heat with the condenser outlet refrigerant in the heat exchanger (5), and its temperature rises, causing Wc Immigration (
6) and is sucked into the compressor port).

At this time, the refrigerant flowing through the pressure reducing device (3) changes as shown in Figure 8 depending on the degree of subcooling at the inlet of the pressure reducing device. As a result, the refrigerant at the inlet of the pressure reducing device (3) is sufficiently cooled to a degree of supercooling as shown in Figure 8B, and the refrigerant flow rate is GB.
It is. On the other hand, at the start of operation, the refrigerant in the suction pipe does not reach a low temperature because the evaporator is warm, so the refrigerant at the inlet of the pressure reducing device (3) is not sufficiently cooled. In this case, a pressure reducing device (
8) The refrigerant at the inlet has a supercooling degree as shown in FIG. 8A, and the refrigerant flow rate is G^.

In this way, in conventional refrigeration cycles, a pressure reducing device is installed to maintain an appropriate flow rate during stable operation.
Although a sufficient flow rate of refrigerant flows as shown in Figure (2) [1], on the other hand, at the start of operation, only an insufficient flow rate flows as shown in Figure 8, and there is a drawback that a sufficient cooling effect cannot be obtained. Ta.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and it is a refrigeration cycle in which a sufficient flow of refrigerant can be obtained even at the start of operation by partially flowing low-temperature refrigerant through the center of the insert. is intended to provide.

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 4, (7) is a tube, (8) is an insert having a spiral groove (8a), and has a bag-shaped cavity (9) in the center that opens downstream, and this bag-shaped A pore Ql) is provided which communicates the cavity (9) of the pressure reducing device with the upstream side of the pressure reducing device.

Next, its effect will be explained. In the above-mentioned pressure reducing device, at the start of operation, the refrigerant passing through the pores Q□ becomes low temperature and low pressure in the cavity (9), and the refrigerant passes through the cavity (9).
, thereby cooling the refrigerant passing through the groove (8a) to increase the degree of subcooling. Therefore, a refrigerant flow rate approximately equal to the refrigerant flow rate G3 during stable operation shown in FIG. 8 is obtained.

On the other hand, during stable operation, since the suction pipe is sufficiently cooled, heat exchange in the heat exchanger (5) shown in Fig. 1 causes
Since the refrigerant liquid reaches the degree of supercooling shown in Figure 8B at the inlet of the pressure reducing device, the refrigerant flow rate is G! equal.

At this time, the refrigerant flowing in the cavity (9) and the groove (8a)
The temperature difference with the refrigerant flowing inside is small, the heat exchange within the pressure reducing device can be almost ignored, and the characteristics during steady operation when there are no pores QQ are realized.

As described above, according to the pressure reducing device of the present invention, a sufficient refrigerant flow rate can always be obtained from the start of operation to the time of steady operation.

In the above embodiment, an insert having a spiral groove is used. However, in a tube (7) having a spiral groove (7&) on the inner wall, as in the 5th WJ, an insert that is in close contact with the inner wall of the tube is used. An insert (8) may also be inserted.

The above example is a simple refrigeration system, but in addition to this simple refrigeration system, it can also be applied to refrigeration systems such as multi-stage refrigeration cycles and multi-stage cascades. The same effect applies to those prepared.

In addition, the shape of the cavity is not limited to circular, but may be any shape.
In addition, if measures are taken to improve heat transfer, such as inserting spiral tape around the four fins into the cavity as shown in Figure 6, good heat exchange characteristics can be obtained. There may be multiple pores, and they do not necessarily need to be in the center or parallel to the tube.For example, #I7
If the pores are formed obliquely so that the refrigerant at the outlet of the pore a1 collides with the cavity wall surface as shown in the figure, heat exchange will be improved and even better performance will be obtained. Also, this pore 00 is the eighth
The same effect can be obtained even if the groove (8a) is formed to communicate with the cavity sQQ as shown in the figure.

As described above, according to the present invention, a portion of the low-temperature refrigerant flows through the center of the insert to ensure a sufficient amount of refrigerant even at the start of operation, thereby improving the start-up characteristics at the start of operation. , stable operation can be achieved from the start of operation to steady operation, and a refrigeration system with high overall efficiency can be obtained.

[Brief explanation of drawings]

Fig. 1 is a cycle diagram of a conventional refrigeration system, Fig. 2 is a diagram showing the structure of a conventional decompression device, Fig. 8 is a diagram showing the relationship between the degree of subcooling and the refrigerant flow rate at the inlet of the decompression device, and Fig. 4 1 is a diagram showing the structure of a pressure reducing device according to an embodiment of the present invention. Figure S ~ No. 8
vA is a diagram showing another embodiment of the present invention. In the figure, (1) is a compressor, (2) is a condenser, (3) is a pressure reducing device, (4) is an evaporator, (5) is a heat exchanger, (6) is a suction pipe, and (7) is a Tube, (8) is insert, (7a) (8
a) is a groove, (9) is a cavity, αQ is a pore, and συ is a fin. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Shin Kuzuno - Figure 1 Figure 2 Figure 3 Figure 4 θ j /Q

Claims (3)

[Claims] (1) Consisting of a tube and an insert that is inserted by adhering to the inner wall of the limb canal, a thin groove is formed between the inner wall of the tube and the outer periphery of the insert so as to communicate the upstream and downstream sides of the tube. In the pressure reducing device, a bag-shaped cavity opening to the downstream side is provided inside the insert, and a pore is provided that communicates this cavity with the upstream side of the pressure reducing device or a part of the narrow groove. A decompression device featuring: (2) The pressure reducing device according to claim 1, characterized in that a fin is provided on the wall surface of the cavity portion of the insert. (3) The pores communicating between the cavity and the upstream side of the decompression device are formed diagonally! A pressure reducing device according to claim 1 or 2.