JPH11325654A - Refrigeration unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigeration unit where the control constitution gets off simple and also which can surely dissolve the occurrence of abnormal sound caused by liquid hammer phenomena or the cracks, etc., of a pipe caused by shock, without leading to sharp cost up. SOLUTION: A refrigeration unit is equipped with a refrigerant circuit where a compressor 1, a condenser 2, a solenoid valve 3, an expansion valve 4, and an evaporator 5 are connected in order in circular form by pipes. Out of them, the solenoid valve 3, the expansion valve 4, and the evaporator 5 are arranged within a facility to be cooled represented by a freezing room. Especially, in the refrigerant circuit of this refrigeration unit, a heater 14 to heat the refrigerant within a high-pressure liquid pipe 8 at least during operation is provided for the high-pressure liquid pipe 8 upstream of the solenoid valve 3. The heater 14 is here constituted of, for example, an electric heater 14a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration system for cooling the inside of a facility to be cooled, such as a freezer.

[0002]

2. Description of the Related Art Conventionally, as this type of refrigeration apparatus, for example, the one disclosed in Japanese Patent Application Laid-Open No. 8-233379 is mentioned. As shown in FIG. 8, the refrigerating apparatus of the above disclosure includes a refrigerant circuit in which a compressor 1, a condenser 2, an electromagnetic valve 3, an expansion valve 4, and an evaporator 5 are sequentially connected in a circular pipe. Among them, the electromagnetic valve 3, the expansion valve 4, and the evaporator 5 are arranged in a freezer (an example of equipment to be cooled, not shown). Also,
It has blowers 6, 7, high-pressure liquid pipes 8, 8a, low-pressure gas pipe 9, thermostat 10, and bypass pipe 11, bypass solenoid valve 12, and capillary tube 13.

[0003] During the cooling operation of the refrigeration system having the above configuration,
The solenoid valve 3 is controlled by a stop command signal from the thermostat 10.
Is closed to perform a pump-down operation, and the compressor 1 is stopped. When the temperature in the freezer rises, the refrigeration apparatus opens the solenoid valve 3 according to the operation command signal from the thermostat 10 and operates the compressor 1 to circulate the refrigerant. At this time, the refrigerant in the high-pressure liquid pipe 8 is cooled by the freezer air during stoppage, and the degree of supercooling increases. At this time, since the liquid density of the refrigerant in the high-pressure liquid pipe 8 is large, a liquid hammer phenomenon is likely to occur when the solenoid valve 3 is opened, which causes a problem such as generation of abnormal sound and cracking of the high-pressure pipe 6a due to impact. Will occur.

Therefore, in the conventional refrigeration system, a bypass pipe 11 having a bypass solenoid valve 12 and a capillary tube 13 is bypassed and connected in parallel with the solenoid valve 3. After the valve 12 is opened to eliminate the pressure difference between the inlet and the outlet of the electromagnetic valve 3, the liquid hammer phenomenon is eliminated by opening the electromagnetic valve 3.

[0005]

Since the conventional refrigeration system is configured as described above, there are the following problems. First, since the bypass solenoid valve 12 and the capillary tube 13 of the bypass pipe 11 must be newly provided in parallel with the solenoid valve 3, this leads to a significant increase in cost.

Further, since it is necessary to make the opening and closing timings of the solenoid valve 3 and the bypass solenoid valve 12 different, a timer or the like must be added, the control structure becomes complicated, and the probability of occurrence of a failure increases.

Also, depending on the fluctuation of the diameter of the bypass solenoid valve 12 and the amount of subcooling of the liquid refrigerant, the liquid hammer phenomenon may not be sufficiently eliminated.

The present invention has been made to solve the conventional problems as described above, and does not lead to a significant increase in cost, simplifies the control configuration, and produces abnormal noise due to the liquid hammer phenomenon. It is an object of the present invention to provide a refrigeration apparatus capable of reliably eliminating a crack or the like of a pipe due to an impact.

[0009]

In order to achieve the above object, a refrigeration apparatus according to the first aspect of the present invention comprises a compressor, a condenser, a solenoid valve, an expansion valve, and an evaporator which are sequentially connected in a ring shape. In a refrigeration system in which a solenoid circuit, an expansion valve, and an evaporator are disposed in the equipment to be cooled, a pipe upstream of the solenoid valve in the refrigerant circuit is provided at least during operation stop. It has a configuration in which a heating unit that heats the refrigerant inside is provided.

The refrigeration apparatus according to the second aspect of the present invention is
The heating section according to claim 1 is configured by an electric heater.

According to a third aspect of the present invention, in the refrigeration apparatus, the piping upstream of the solenoid valve in the refrigerant circuit of the first or second aspect is disposed higher than the installation position of the solenoid valve. Is formed.

Further, the refrigeration apparatus according to the fourth aspect of the present invention,
A refrigeration system including a refrigerant circuit in which a compressor, a condenser, a solenoid valve, an expansion valve, and an evaporator are sequentially connected in a circular pipe, and the solenoid valve, the expansion valve, and the evaporator are arranged in the equipment to be cooled. In the device, a large space portion having a larger pipe cross-sectional area than a pipe upstream of the solenoid valve is formed in a pipe between the solenoid valve and the expansion valve in the refrigerant circuit.

[0013] Further, a refrigeration apparatus according to the invention of claim 5 comprises:
The large space portion according to claim 4 is configured by a muffler.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

Embodiment 1 of the Invention FIG. 1 is a refrigerant system diagram of a refrigeration apparatus showing the first embodiment of the present invention, FIG. 2 is a partial side view of the refrigeration apparatus showing the first embodiment of the present invention, and FIG. 3 shows another embodiment of the first embodiment of the present invention. FIG. 4 is a partial side view of the refrigeration apparatus showing another embodiment of the first embodiment of the present invention, and FIG. 5 is a view showing the state of the refrigerant at the start of operation of the refrigeration apparatus showing the first embodiment of the present invention. FIG. 3 is a Mollier chart representing the above. However, the same components as those of the refrigeration apparatus shown in FIG.

In the refrigerant circuit of the refrigeration apparatus shown in FIG. 1, a high-pressure liquid pipe 8 (an example of a pipe upstream of the solenoid valve 3) is
A heating unit 14 that heats the refrigerant inside is provided. Here, as the heating unit 14, as shown in FIG. 2, for example, an electric heater 14a is attached to the lower surface of the high-pressure liquid pipe 8, and is always energized. However, the power supply to the electric heater 14a does not need to be performed at all times, and may be performed at least during operation stop. In addition, the heating unit 14 only needs to have a predetermined heating capability, and is not limited to an electric heater.

As shown in FIG. 3, the electric heater 14a can be spirally wound around the high-pressure liquid pipe 8. Further, as shown in FIG. 4, it is preferable to cover the high pressure liquid pipe 8 and the electric heater 14a with a heat insulating pipe 14b in order to prevent the electric heater 14a from leaking heat.

Therefore, the liquid refrigerant accumulated in the high-pressure liquid pipe 8 during operation stop is heated by the electric heater 14a and evaporates, and the temperature changes on the Mollier diagram shown in FIG. To a two-phase state. At this time, when the solenoid valve 3 is opened by the operation command signal from the thermostat 10, the refrigerant in the high-pressure liquid pipe 8 is guided to the expansion valve 4 in a two-phase state.

Therefore, since a part of the liquid refrigerant accumulated in the high-pressure liquid pipe 8 is heated and evaporated by the heating unit 14 to be in a two-phase state, the gas refrigerant in the two-phase refrigerant has a cushioning effect.
The liquid hammer phenomenon at the start of operation is eliminated with a simple control configuration. Moreover, when the heating unit 14 is the electric heater 14a, the heating temperature control is easy, and it is easy to obtain and inexpensive.

Embodiment 2 of the Invention FIG. 6 is a partial side view of a refrigeration apparatus showing Embodiment 2 of the present invention. In FIG. 6, the high-pressure liquid pipe 8 on the upstream side of the solenoid valve 3 of the refrigerant circuit is formed as a vertical U-shaped portion 8b in which the U-shape is turned 90 degrees when viewed from the side. The upper end of the vertical U-shaped portion 8b is the solenoid valve 3
Is located higher than the installation position of the gas reservoir 8c. The gas reservoir 8c heats the refrigerant in the vertical U-shaped portion 8b by energizing the electric heater 14a, and intentionally retains the refrigerant that has been heated and gasified while the operation is stopped. is there. The energized state of the electric heater 14a and the timing at which the solenoid valve 3 is opened are the same as in the first embodiment of the invention described above.

Therefore, in this embodiment, the gas reservoir 8c is provided at a position higher than the electromagnetic valve 3 so that the refrigerant gasified by heating flows through the high-pressure liquid pipe 8 toward the electromagnetic valve 3 due to a temperature difference. Even if it moves, it stays in the gas reservoir 8c and functions as a cushion at the start of the operation, so that the liquid hammer phenomenon is eliminated.

Embodiment 3 of the Invention FIG. 7 is a refrigerant system diagram of a refrigeration apparatus showing Embodiment 3 of the present invention. However, the same components as those of the refrigeration apparatus shown in FIG. In FIG. 7, the solenoid valve 3 and the expansion valve 4
A large space portion 15 having a larger cross-sectional area than the high-pressure liquid pipe 8 on the upstream side of the solenoid valve 3 is formed in the high-pressure liquid pipe 8a. Here, as the large space portion 15, for example, a muffler 15a that also has a noise reduction effect is employed. Then, when the solenoid valve 3 is opened by an operation command signal from the thermostat 10, the refrigerant in the high-pressure liquid pipe 8 passes through the high-pressure liquid pipe 8a from the solenoid valve 3 and passes through the inside of the muffler 15a having a large internal space to the expansion valve 4. It is led.

Therefore, in this embodiment, the large space 15 provided in the high-pressure liquid pipe 8a between the solenoid valve 3 and the expansion valve 4 serves as a cushion at the start of operation, so that the impact caused by the liquid hammer is reduced. Absorbed. This eliminates the liquid hammer phenomenon with a simple configuration. In addition, since an easily available and inexpensive muffler is used as the large space, a muffler effect is also exhibited.

[0024]

As described above in detail, according to the first aspect of the present invention, the heating unit provided in the piping on the upstream side of the solenoid valve heats the liquid refrigerant having a large degree of supercooling during operation stop and partially evaporates. Since the two-phase state is established, the liquid hammer phenomenon at the start of operation can be eliminated, and generation of abnormal noise and cracks in piping and the like due to impact can be prevented. In addition, since it is not necessary to use a bypass solenoid valve or a timer as in the related art,
There is no significant cost increase. Further, since the control configuration is simple, the failure probability can be reduced.

Further, when the heating section is constituted by an electric heater as in the second aspect of the present invention, it is needless to say that the liquid hammer phenomenon can be eliminated by a low-cost and simple control structure. And it is cheaper and the control of the heating temperature becomes easy.

According to the third aspect of the present invention, since the piping upstream of the solenoid valve in the refrigerant circuit is provided with the gas reservoir located higher than the position where the solenoid valve is installed, the heating during operation is stopped. Even if a part of the refrigerant gasified by the operation of the part moves in the pipe due to the temperature difference, it stays in the gas reservoir in front of the solenoid valve. That is, the gas refrigerant retained in the gas reservoir serves as a cushion at the start of the operation, so that abnormal noise due to the liquid hammer phenomenon at that time and cracks in pipes and the like due to impact can be reliably prevented.

Further, according to the fourth aspect of the present invention, since a large space portion having a larger pipe cross-sectional area than the pipe on the upstream side of the solenoid valve is formed in the pipe between the solenoid valve and the expansion valve, This large space portion serves as a cushion at the start of operation and absorbs the shock at that time. Therefore, the liquid hammer phenomenon can be eliminated by a simple configuration without employing a complicated control configuration.

Further, when the large space portion is constituted by a muffler as in the invention according to claim 5, it goes without saying that the liquid hammer phenomenon can be eliminated without providing a complicated control circuit, and it is easy to obtain parts. In addition, it is inexpensive and has a high noise reduction effect.

[Brief description of the drawings]

FIG. 1 is a refrigerant system diagram of a refrigeration apparatus showing Embodiment 1 of the present invention.

FIG. 2 is a partial side view of the refrigeration apparatus showing Embodiment 1 of the present invention.

FIG. 3 is a partial side view of a refrigeration apparatus showing another embodiment of the first embodiment of the present invention.

FIG. 4 is a partial side view of a refrigeration apparatus showing another embodiment of the first embodiment of the present invention.

FIG. 5 is a Mollier diagram of the refrigeration apparatus showing the first embodiment of the present invention.

FIG. 6 is a partial side view of a refrigeration apparatus showing Embodiment 2 of the present invention.

FIG. 7 is a refrigerant system diagram of a refrigeration apparatus showing Embodiment 3 of the present invention.

FIG. 8 is a refrigerant system diagram showing a conventional refrigeration apparatus.

[Explanation of symbols]

1 compressor, 2 condenser, 3 solenoid valve, 4 expansion valve, 5
Evaporator, 8 high-pressure liquid pipe, 8a high-pressure liquid pipe, 8c gas reservoir, 14 heating section, 14a electric heater, 15 large space section, 15a muffler.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Koichi Negoro 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation

Claims (5)

[Claims] 1. A refrigerant circuit comprising a compressor, a condenser, a solenoid valve, an expansion valve, and an evaporator, which are sequentially connected in a circular pipe, and wherein the solenoid valve, the expansion valve, and the evaporator are cooled. In the refrigerating device arranged in the facility,
A refrigerating apparatus, wherein a heating unit for heating a refrigerant in the piping at least during an operation stop is provided in a piping on the upstream side of the electromagnetic valve in the refrigerant circuit. 2. The refrigeration apparatus according to claim 1, wherein the heating section is constituted by an electric heater. 3. The gas reservoir according to claim 1, wherein a piping upstream of the solenoid valve in the refrigerant circuit is arranged higher than a position where the solenoid valve is installed.
Item 3. The refrigeration apparatus according to item 1. 4. A refrigerant circuit comprising a compressor, a condenser, a solenoid valve, an expansion valve, and an evaporator sequentially connected in a circular pipe, and wherein the solenoid valve, the expansion valve, and the evaporator are cooled. In the refrigerating device arranged in the facility,
A refrigerating apparatus, wherein a large space portion having a larger pipe cross-sectional area than a pipe upstream of the solenoid valve is formed in a pipe between the solenoid valve and the expansion valve in the refrigerant circuit. 5. The refrigeration apparatus according to claim 4, wherein the large space portion is formed by a muffler.