JPS5851579Y2 - Heated expansion valve in refrigeration circuit - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an expansion valve in a refrigeration circuit of a chilling unit, which requires cooling even in winter, for example.

The purpose of this invention is to provide a heated expansion valve for a refrigeration circuit, which prevents a malfunction of the expansion valve from causing an extreme drop in capacity during winter operation of a refrigeration circuit such as a chilling unit. It is in.

To explain this device with reference to the drawings, high-pressure refrigerant gas discharged from a compressor 1 is liquefied in a condenser 2, and this refrigerant whose pressure is lowered in an expansion valve 3 is vaporized in an evaporator 4 and compressed through a return pipe 5. It is sucked into machine 1.

This evaporator 4 is used to cool a heating element unrelated to the outside air, and is used as a shell-and-tube heat exchanger, for example, to cool an intermediate refrigerant such as water.

The refrigeration load is detected by a heat-sensitive cylinder 6 disposed in the return pipe 5, and the gas in the heat-sensitive cylinder 6 is conducted through a conduit 7 to the operation part of the expansion valve 3, thereby controlling the opening degree of the expansion valve 3. to correspond to fluctuations in

This type of operating method of the expansion valve 3 using a heat-sensitive cylinder 6 is a normal gas-charge type expansion valve, and when the refrigerant load increases, the temperature of the return pipe 5 increases, and the temperature of the return pipe 5 is slightly enclosed in the heat-sensitive cylinder. The refrigerant vaporizes from a liquid state to a gaseous state and increases the pressure, thereby operating the expansion valve 3 to open.

Conversely, when the temperature inside the tube 5 decreases, the gas inside the heat-sensitive cylinder 6 condenses and liquefies, and the gas pressure decreases, so that the expansion valve 3 closes.

Chilling units, especially air-cooled chilling units (air-cooled chillers), are installed in locations where the temperature is similar to the outdoor temperature, and in the summer, the temperature of the refrigerant in the return pipe 5, e.g. 15°C, is lower than the outside air temperature, e.g. 30°C, which poses a problem. There isn't.

However, in winter, when the temperature of the outside air drops to 15° C. or lower, the temperature of the operating gas in the expansion valve 3 becomes lower than the temperature of the operating gas in the heat-sensitive cylinder 6.

Therefore, liquid refrigerant accumulates in the diaphragm operation chamber (not shown) of the expansion valve 3, that is, this liquid flows from the heat-sensitive cylinder 6 to the expansion valve 3.
The opening degree of the expansion valve 3 is controlled by the low outside air temperature on the expansion valve 3 side.

In this case, the amount of refrigerant required by the evaporator 4 is no longer supplied, the suction pressure of the compressor decreases, and the capacity becomes extremely low.

This invention solves this inconvenience, and measures are taken by connecting an electric heater 8 to the operation chamber of the expansion valve 3 in a thermally conductive manner and surrounding it with a heat insulating material 9.

This heater 8 has an automatic temperature control switch 10 such as a thermostat arranged in series with a power source 11.

For example, if the set temperature of the evaporator 4 is 15°C as described above, the automatic temperature control switch 10 is closed when the outside air is below 15°C.

That is, the temperature of the diaphragm operation chamber is automatically controlled to be maintained at about 15°C.

Of course, the temperature of the operation chamber caused by this heater 8 is not limited to 15°C, and the temperature of the operation chamber sealed in the operation refrigerant is not tampered with, and the opening degree of the expansion valve 3 is optimized in relation to the temperature of the temperature sensing cylinder 6. Just maintain a controlled temperature.

Thereby, the amount of refrigerant required by the evaporator 4 can be constantly supplied, and efficient operation can be maintained without causing a decrease in the capacity of the refrigeration circuit.

In addition, the structure is simple and there are no parts where failures can occur.

[Brief explanation of drawings]

The drawing is a schematic piping diagram of a refrigeration circuit equipped with a heated expansion valve according to this invention. In the drawings, numeral 3 is an expansion valve, 6 is a heat-sensitive tube, and 8 is a heater.

Claims (1)

[Scope of utility model registration request] A diaphragm operation chamber is provided in the expansion valve of the refrigeration circuit, and a heat-sensitive cylinder 6 is provided in the return pipe 5 of the refrigeration circuit, and these diaphragm operation chambers and the heat-sensitive cylinder 6 are connected by a conduit 7, and an operation is performed within the diaphragm operation chamber. A heated expansion valve for a refrigeration circuit in which a refrigerant gas is sealed and a heater is attached to the diaphragm operation chamber.