JPH02187567A - Freezing device - Google Patents

Abstract

PURPOSE:To reduce the occurrence of liquid hammer phenomenon by providing a bypass piping bypassing a solenoid valve for a refrigerant liquid pipe and an opening and closing means to open and close the passage according to a difference in a pressure between the inlet and the outlet of a solenoid valve for refrigerant pipe and perform opening and closing according to the refrigerant liquid temperature of the inlet of a solenoid valve for a refrigerant liquid pipe. CONSTITUTION:Since, when the temperature of the interior of a chamber is reduced to a given value, for example, -30 deg.C, a contact 10a of a thermostat 10 is opened, a solenoid valve 3 for a refrigerant liquid pipe is de-energized and closed. Further, since an electromagnetically opening and closing passage 15 is also de-energized to open a contact 15a, energization of a thermo 14 is blocked to stop a compressor 1. Meanwhile, when, during closing of a solenoid valve 3 for a refrigerant pipe, a difference in a pressure between the inlet and the outlet of the solenoid valve 3 for a refrigerant pipe exceeds a given pressure, for example, 9.5kg/cm<2>, a differential pressure switch 13 is actuated to close a contact 13a. Thereby, a solenoid valve 12 for bypass is brought into on energized state to open the passage of a bypass piping 11. The inlet and the outlet of the solenoid valve 3 for a refrigerant pipe are interconnected through the bypass piping 11, resulting in the possibility to reduce a difference in a pressure between the inlet and the outlet thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a refrigeration device for cooling the inside of a freezer, for example.

[Conventional technology]

FIG. 5 is a refrigerant system diagram of a conventional refrigeration system.

In the figure, 1 is a compressor, 2 is a condenser, 3 is a solenoid valve for refrigerant liquid pipe, 4 is an expansion valve, and 5 is an evaporator, which are connected in sequence. It is provided with an air blower 56 for blowing air into the refrigerator. These are installed as shown in Fig. 6, 7 is a freezer, 8 is a high pressure liquid pipe connected from the condenser 2 to the refrigerant liquid pipe solenoid valve 3, and 8a is from the refrigerant liquid pipe solenoid valve 3 to the expansion valve 4. It is a high pressure liquid pipe connected.

9 is a low pressure gas pipe connected from the expansion valve 4 to the evaporator 5;
10 is a thermostat for controlling the temperature inside the freezer 7.

Next, the operation will be explained. When the temperature inside the freezer 7 is higher than a predetermined temperature, the compressor 1 is operated by the switch action of the thermostuff 10, and the solenoid valve 3 for the refrigerant liquid pipe is in an open state.

The high temperature and high pressure gas refrigerant discharged from the compressor 1 is sent to the condenser 2.
The refrigerant is condensed inside and becomes a high-pressure liquefied refrigerant. The liquefied refrigerant is lowered in pressure by passing through the expansion valve 4, is further evaporated in the evaporator 5, exchanges heat with the air in the freezer 7, and is sucked into the compressor 1 as a low-pressure gas refrigerant. By repeating this refrigeration cycle, the air inside the freezer 7 is cooled. When the internal temperature of the freezer 7 falls below a predetermined value, the compressor 1 is stopped by the switch action of the thermostat 10, and the refrigerant liquid pipe electromagnetic valve 3 is closed.

Figure 7 shows the impact pressure P that occurs when the circuit opens due to the pressure difference ΔP between the inlet and outlet of the refrigerant liquid pipe solenoid valve 3 when the liquefied refrigerant temperature on the inlet side of the refrigerant liquid pipe solenoid valve 3 is kept constant at -30°C. . This is a graph. FIG. 8 shows the impact pressure P versus the inlet liquefied refrigerant temperature TL using the pressure difference ΔP as a parameter. This is a graph.

[Problem to be solved by the invention]

Conventional refrigeration equipment is configured as described above, so when the outside temperature is high in the summer, the pressure difference between the inlet and outlet of the closed solenoid valve 3 for the refrigerant liquid pipe increases, and in this pressure state, When the refrigerant liquid pipe solenoid valve 3 is opened, the liquefied refrigerant in the high-pressure liquid pipe 8 rapidly flows into the expansion valve 4 through the high-pressure liquid pipe 8a, causing liquid hammer development in the expansion valve 4, causing excessive impact pressure. In some cases, the liquefied refrigerant passes through the expansion valve 4 and then flows back to the compressor 1 side, causing valve cracking or seizure of the compressor 1.

As can be understood from FIGS. 7 and 8, for example, the outside temperature is 40°C, the inside temperature is -30°C, and the liquefied refrigerant temperature on the inlet side is -
At 30℃, the pressure difference ΔP is 15 kg/cd, which is 8
'r! As for the pressure PM, a pressure of about 75 to 1 r/cd is generated, which far exceeds the maximum withstand pressure of 45 kg/cj of the expansion valve 4, making it impossible to control the refrigeration cycle normally.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to obtain a refrigeration system that can reduce liquid hammer development by controlling the opening and closing of a bypass path that bypasses a solenoid valve for a refrigerant liquid pipe. With the goal.

[Means to solve the problem]

The refrigeration system according to the present invention includes a refrigerant liquid pipe type (■ bypass pipe that bypasses the valve, and an opening/closing means that opens and closes this passage according to the pressure difference between the inlet and outlet of the refrigerant liquid pipe solenoid valve. It was established.

In addition to the above configuration, the refrigeration device according to another aspect of the present invention
The opening/closing means is configured to open and close depending on the temperature of the refrigerant liquid at the inlet of the solenoid valve for the refrigerant liquid pipe.

[For production]

In the refrigeration system of the present invention, when the pressure difference exceeds a predetermined pressure, the opening/closing means opens the passage of the bypass piping to reduce the pressure difference.

In the refrigeration system according to another aspect of the present invention, when the pressure difference is above a predetermined pressure or when the inlet side refrigerant liquid temperature is below a predetermined temperature, the opening/closing means opens the passage of the bypass piping to reduce the pressure difference.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a refrigerant system diagram according to an embodiment of the present invention. In Figure 1, parts that are the same as those in the conventional example have the same reference numerals as in Figure 5.
-6.8 to 10 will be assigned, and the explanation thereof will be omitted. 1) is a bypass pipe provided to bypass the refrigerant liquid pipe solenoid valve 3, 12 is a bypass solenoid valve provided in the middle of the bypass pipe 1), and 13 is between the inlet and outlet of the refrigerant liquid pipe solenoid valve 3. This is a differential pressure switch that opens and closes the contacts by detecting the pressure difference between the two.

FIG. 2 is an electrical circuit diagram of the refrigeration system shown in FIG. 1.

In FIG. 2, 14 is a motor for driving the compressed ml, 15 is an electromagnetic switch having a contact 15a provided between the motor 14 and a three-phase power source (not shown), 16 is a driving switch, and 10a is a A contact point 13a of the thermostat 10 is a contact point of the differential pressure switch 13. Connected between the two phases of the power supply are a series connection of a contact 13a and a bypass electromagnetic valve 12, and a series connection of an operation switch 16, a contact 10a, and an IT 13 valve 3 for refrigerant liquid pipes. An electromagnetic switch 15 is connected in parallel to the refrigerant liquid pipe electromagnetic valve 3, and a blower 6 is connected in parallel to the series connection between the parallel connection and the contact 10a.

Next, the operation will be explained with reference to FIGS. 1 and 2. When the driver closes the operation switch 16 to start operation, the blower 6, the refrigerant liquid pipe solenoid valve 3, and the solenoid switch 1
5 starts to be energized. As a result, the blower 6 becomes operational, the refrigerant liquid pipe electromagnetic valve 3 opens, and the contact 15a of the electromagnetic switch 15 closes. When the contact 15a is closed, the motor 14 is energized and the compressor 1 is driven to perform refrigeration operation. This freezing operation lowers the temperature inside the refrigerator. When the temperature inside the refrigerator reaches a predetermined temperature (for example, -30° C.), the contact 10a of the thermostat IO opens, and the solenoid valve 3 for the refrigerant liquid pipe is deenergized and closed. Further, the electromagnetic switch 15 is also deenergized and the contact 15a is opened, thereby blocking the energization of the motor 14 and stopping the compressor l. Thereafter, when the temperature inside the refrigerator rises to a predetermined temperature (for example, -27° C.), the contact 10a of the thermostat 1° is closed, and the above-mentioned refrigeration operation state is entered.

On the other hand, when the refrigerant liquid pipe solenoid valve 3 is closed, the pressure difference between the inlet and outlet of the refrigerant liquid pipe solenoid valve 3 is a predetermined pressure (for example, 9.
5 kir/cd) or more, the differential pressure switch 13 operates and closes its contact 13a. For this purpose, the bypass solenoid valve 12 is energized to open the passage of the bypass pipe 1). Therefore, the inlet and outlet of the refrigerant liquid pipe electromagnetic valve 3 are communicated via the bypass pipe 1), so that the pressure difference between the person and the outlet can be reduced. Then, the solenoid valve 3 for the refrigerant liquid pipe
The pressure difference between the inlet and outlet of the
), the contact 13a of the differential pressure switch 13 is opened, so the bypass solenoid valve 12 is deenergized and the passage of the bypass pipe 1) is closed. As mentioned above, when the refrigerant liquid pipe solenoid valve 3 is closed, the pressure difference between the person and the outlet is as small as 9.5 kg/cJ at maximum, so the fJi shock that occurs when the refrigerant liquid pipe solenoid valve 3 is opened is As shown in FIG. 7, the maximum pressure is 45 kir/cli, which is within the pressure resistance range of the expansion valve 4. By repeating the above operations as described above, the temperature inside the refrigerator is controlled to a predetermined temperature.

3 and 4 show a second embodiment of the present invention, in which the same parts as in the first embodiment are given the same reference numerals 1 to 6.8 to 16. Reference numeral 17 denotes a thermostand for refrigerant liquid temperature that is installed as shown in FIG. 6, and its contact 17a is connected to the differential pressure switch 1
It is connected in parallel to the contact point 13a of No. 3. The rest of the configuration is the same as that of the first embodiment shown in FIGS. 1 and 2, so a description thereof will be omitted.

The pressure difference between the inlet and outlet of the solenoid valve 3 for refrigerant liquid pipe is a predetermined pressure (
16 kg/cj) or more, or when the refrigerant liquid temperature on the inlet side of the refrigerant liquid pipe solenoid valve 3 is below a predetermined temperature (for example, 12°C), the contact 13a of the differential pressure switch 13 or the contact of the refrigerant liquid temperature thermostat 17 17a closes. The closing action of this contact opens the bypass solenoid valve 12, opening the passage of the bypass piping 1). As a result, the refrigerant liquid pipe solenoid valve 3
It is possible to reduce the pressure difference between the inlet and outlet of the or,
When the pressure difference is below a predetermined pressure (for example, 4 kr/aJ) and the temperature of the inlet refrigerant is above a predetermined temperature (for example, 20° C.), both contacts 13a and 17a open to deenergize the bypass solenoid valve 12. This blocks the passage of the bypass pipe 1). As shown in FIG. 8, the impact pressure when the valve opens changes depending on the temperature of the liquefied refrigerant at the inlet of the solenoid valve 3 for refrigerant liquid pipes. &, This also occurs in the case of this embodiment, in which the passage of the bypass pipe 1) is opened and closed according to the temperature of the liquefied refrigerant on the inlet side using the warming thermostand 17 to reduce the impact pressure when the ζ valve is opened. A city to do? Maximum pressure is 45kg
/-, so it is within the pressure strength range of the expansion valve 4.

〔Effect of the invention〕

As described above, according to the present invention, the solenoid valve for refrigerant liquid pipe
When the pressure difference between the outlets reaches a predetermined pressure or higher, a bypass passage that bypasses the solenoid valve is opened, so the pressure between the inlet and outlet of the solenoid valve for the refrigerant liquid pipe is reduced, and during the valve operation, the liquid hammer Since the impact pressure is kept below the withstand pressure of the expansion valve, the expansion valve will not be destroyed, and the compressor valve will not crack or seize due to liquid bank operation, resulting in a long service life. There is.

In addition, the bypass passage is opened not only when there is a pressure difference but also when the temperature of the refrigerant on the inlet side is below a predetermined temperature, which reduces the pressure difference, more reliably prevents damage to the refrigeration cycle, and increases the lifespan of the refrigerant. There are benefits to be gained.

[Brief explanation of the drawing]

FIG. 1 is a refrigerant system diagram of a refrigeration system according to an embodiment of the present invention, FIG. 2 is a circuit diagram of the system of FIG. 1, and FIG. 3 is a refrigeration system according to another embodiment of the present invention. 4 is a circuit diagram of the device shown in FIG. 3, FIG. 5 is a refrigerant system diagram of a conventional refrigeration gA unit, FIG. 6 is a diagram showing the conventional device installed in a freezer, Figure 7 is a diagram showing the relationship between the pressure difference between the inlet and outlet of the solenoid valve for the refrigerant liquid pipe and the impact pressure, and Figure 8 shows the relationship between the artificial side refrigerant liquid temperature and the impact pressure using the pressure difference as a parameter. - It is a diagram. In the figure, 1... Compressor, 2... Condenser, 3... Solenoid valve for refrigerant liquid pipe, 4... Expansion valve, 5... Evaporator, 8,
8a...High pressure liquid pipe, 9...Low pressure gas pipe, 10...
・Thermostat, 1)...Bypass piping, 12...
・Bypass solenoid valve, 13... Differential pressure switch, 17.
・Refrigerant liquid abuse thermostat・ In addition, the same reference numerals in the drawings indicate the same or equivalent parts. Agent Masu Oiwa Diagram +1 Diagram 5n

Claims (2)

[Claims] (1) In a refrigeration system in which a compressor, a condenser, a solenoid valve for a refrigerant liquid pipe, an expansion valve, and an evaporator are sequentially connected to constitute a refrigeration cycle, a bypass pipe that bypasses the solenoid valve for the refrigerant liquid pipe, and a refrigerant A refrigeration system comprising an opening/closing means for opening/closing a passage of the bypass piping according to a pressure difference between an inlet and an outlet of a liquid pipe electromagnetic valve. (2) The refrigeration system according to claim 1, wherein the opening/closing means opens and closes the passage of the bypass piping depending on the refrigerant liquid temperature on the inlet side of the refrigerant liquid pipe electromagnetic valve.