JP2011241985A - Refrigerating/freezing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the reliability of a cycle including injection capillary.SOLUTION: The refrigerating/freezing device, in which a compressor, a condenser, an expansion valve, and an evaporator are sequentially connected, includes a liquid injection circuit for performing liquid-injection of a refrigerant branched from between the condenser and the expansion valve to a compressor slot part of the compressor. It includes an injection capillary equipped with a capillary tube, a pipe which has an inside diameter that is larger than the outside diameter of the capillary tube and wraps the capillary tube, and a joint pipe which is fitted to an end of the pipe so as to cover a brazed portion after both ends of the pipe are shrunk and brazed to the capillary tube. The injection capillary is a part of the liquid injection circuit.

Description

  The present invention relates to a refrigeration apparatus, and more particularly to an apparatus having a cycle having an injection capillary which is a flow rate control mechanism for adjusting an injection flow rate.

  In the conventional refrigeration system, as described in, for example, Patent Document 1, in order to prevent pulsation of the liquid injection circuit at the time of starting the compressor, means for closing the liquid injection circuit before the compressor is stopped, or the compressor Means are provided for opening the injection circuit after startup.

JP 2002-130850 A

  In the refrigeration cycle, the compressor discharge temperature becomes high because the pressure ratio between the suction pressure and the discharge pressure is larger than that in the air-conditioning refrigeration cycle. In order to prevent an increase in the discharge temperature of the compressor, a liquid injection circuit that communicates the liquid refrigerant branched from between the condenser and the expansion valve to the compression mechanism of the compressor is provided, and the vaporization heat of the liquid refrigerant is used. It prevents the discharge temperature from rising and the compressor itself from overheating.

  The injection capillary, which is a part of this liquid injection circuit and is a flow control mechanism for adjusting the liquid injection flow rate, is a thin tube, so it deforms when transporting the injection capillary alone or assembling it into a cycle. There is a fear. In such a case, there is no problem in particular because we are careful enough, but in the worst case it may cause damage and it can not be said that the possibility is zero .

  In addition, the injection capillary is stressed by vibration during starting and operation of the compressor after cycle installation, and there is a large difference in diameter between the piping on the compressor side and the piping on the cycle side. Stress may be concentrated on the surface, and these effects may cause pipe cracking or damage to parts, and it cannot be said that the possibility is zero.

  An object of the present invention is to improve the reliability of a cycle having an injection capillary.

In order to achieve the above object, the present invention
A liquid injection unit configured to sequentially connect a compressor, a condenser, an expansion valve, and an evaporator, and causes the refrigerant branched from between the condenser and the expansion valve to be liquid-injected into the compression mechanism of the compressor. In the refrigerator-freezer equipped with a circuit,
A capillary tube;
A pipe having an inner diameter larger than the outer diameter of the capillary tube and enclosing the capillary tube;
Both ends of the pipe are contracted and brazed to the capillary tube, and a joint pipe attached to the end of the pipe so as to cover the brazed portion;
With an injection capillary with
The injection capillary is part of a liquid injection circuit.

  According to the present invention, cycle reliability is improved.

The figure which shows the injection capillary of 1st Example of this invention. The figure which shows the manufacture process of the injection capillary of 1st Example of this invention. The figure which shows the basic freezing cycle system | strain of the freezing apparatus in which the injection capillary of this invention is used. FIG. 4 is a detailed view showing an injection capillary attachment portion in FIG. 3.

  Embodiments of the present invention will be described below with reference to the drawings. The same reference numerals in the drawings of the embodiments indicate the same or equivalent.

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

  FIG. 1 shows an injection capillary 1 according to a first embodiment of the present invention, and FIG. 2 shows a manufacturing process of the injection capillary 1.

  FIG. 1 shows the entire injection capillary 1. The injection capillary 1 is disposed as a part of the liquid injection circuit 6 at a position as shown in FIG.

  The configuration of the injection capillary 1 is basically a capillary tube 2. In FIG. 3, it is curled up, but this is just a symbol and may be a straight line. As described above, when the capillary tube 2 is disposed in the cycle, a throttle function is exhibited in this portion.

  The pipe 3 and the capillary tube 2 have a double tube structure so as to cover the outside of the capillary tube 2. Although the brazed portions 3a and 3b of the capillary tube 2 and the pipe 3 will be described later, joint pipes 4a and 4b are attached so as to cover the brazed portions 3a and 3b of the capillary tube 2 and the pipe 3. The ends of the joint pipes 4a and 4b are xa and xb in FIG. In addition, as shown in FIG. 1, in order to protect the front-end | tip of the capillary tube 2, the joint pipe 4a has covered the edge part of the capillary tube 2. As shown in FIG.

  As the joint pipes 4a and 4b, pipes having the same inner diameter of 3.36 mm as the pipe 3 were used. One end of the pipe is expanded to an inner diameter of 5 mm, and connected to the pipe 3 and brazed so as to cover the brazed portions 3a and 3b. The pipe 3 has the same diameter as a pipe constituting a refrigeration cycle, which will be described later, and may have the same diameter.

  For the brazed portions 3a and 3b of the capillary tube 2 and the pipe 3, as shown in FIG. 2, the capillary tube 2 having an outer diameter of 1.8 mm is covered with the pipe 3 having an inner diameter of 3.36 mm, and both ends of the pipe 3 are squeezed. Then, the capillary tube 2 is brazed. The size and shape of the capillary tube 2 are determined according to the injection resistance value, and the size and shape of the pipe 3 are designed so as to enclose the capillary tube 2 while leaving both ends.

  The injection capillary 1 is a refrigerant branched from between the condenser 8 and the expansion valve 10 in the refrigeration cycle in which the compressor 7, the condenser 8, the expansion valve 10, and the evaporator 11 are sequentially connected as shown in FIG. Is attached as a flow rate control mechanism for adjusting the liquid injection flow rate to the liquid injection circuit 6 that communicates with the compression mechanism portion of the compressor 7. Although the scroll compressor is used in this embodiment, it can also be used for a rotary compressor and a reciprocating compressor.

  A portion where the injection capillary 1 is attached to the refrigeration apparatus is shown in FIG. FIG. 4 shows the xa portion in an enlarged manner. The injection capillary 1 joins a brazed joint pipe 4a to a cycle side pipe at an end xa. Further, although not shown, the joint pipe 4b is joined to the compressor-side pipe 5 at the end portion xb.

  Thus, by connecting the joint pipe to the compressor, the capillary tube and the compressor are not directly connected, reducing the stress applied to the capillary tube 2 and reducing the stress concentration due to the diameter difference of the pipe connection portion. It is possible to alleviate and reliably prevent the refrigerant in the cycle from leaking due to pipe cracks or component breakage.

  As described above, the injection capillary has a double tube structure in which the capillary tube is enclosed by a pipe having an inner diameter larger than its outer diameter, both ends of the pipe are contracted, and brazed to the capillary tube. Alternatively, the connection part with the cycle is made by a joint part connected to the pipe, and the structure is such that the injection capillary and the compressor or the cycle piping are not directly connected, so that the function of the injection capillary is not impaired. In addition to reducing the stress applied to the tube, stress concentration due to the diameter difference of the pipe connection portion can be reduced, and leakage of refrigerant in the cycle due to pipe cracks and component damage can be reliably prevented.

  When the refrigerant used in the refrigeration apparatus is a flammable refrigerant such as propane or isobutane, the leakage prevention is particularly important because the refrigerant leakage can cause a fire or an explosion.

DESCRIPTION OF SYMBOLS 1 Injection capillary 2 Capillary tube 3 Pipe 4a, 4b Joint pipe 5 Compressor piping 6 Liquid injection circuit 7 Compressor 8 Condenser 9 Liquid receiver 10 Expansion valve 11 Evaporator

Claims (2)

A liquid injection unit configured to sequentially connect a compressor, a condenser, an expansion valve, and an evaporator, and causes the refrigerant branched from between the condenser and the expansion valve to be liquid-injected into the compression mechanism of the compressor. In the refrigerator-freezer equipped with a circuit,
A capillary tube;
A pipe having an inner diameter larger than the outer diameter of the capillary tube and enclosing the capillary tube;
Both ends of the pipe are contracted and brazed to the capillary tube, and a joint pipe attached to the end of the pipe so as to cover the brazed portion;
With an injection capillary with
2. A refrigeration apparatus, wherein the injection capillary is part of a liquid injection circuit. In claim 1,
The refrigerator / freezer, wherein the joint pipe covers an end of the capillary tube.

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