JPH04302968A - Gas filling device for temperature-sensitive cylinder of expansion valve - Google Patents

Abstract

PURPOSE:To provide a gas filling device which is capable of filling gas mixture of refrigerant gas and inert gas into a temperature-sensitive cylinder of an expansion valve while the mixing ratio is accurately controlled, is easy to handle and does nut discharge refrigerant gas into the atmosphere. CONSTITUTION:A refrigerant tank 11 stores liquid refrigerant in the lower part and is connected to a temperature-sensitive cylinder 1 at a position above the liquid refrigerant level. A refrigerant tank temperature controller 12 controls the temperature of the refrigerant tank 11 so that the refrigerant saturated vapor pressure agrees with the pressure of refrigerant gas to be filled in the temperature-sensitive cylinder 1. An inert gas tank 14 stores inert gas to be filled in the temperature-sensitive cylinder 1 and is connected to the refrigerant tank 11, and a pressure controller 15 controls the inner pressure of the inert gas tank 14 so that it becomes equal to the sum of the pressures of the inert gas and refrigerant gas to be filled into the temperature-sensitive cylinder 1. A check valve 18 is provided so that gas is able to flow only from the inert gas tank 14 to the refrigerant tank 11.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas filling device for a temperature-sensing tube of an expansion valve provided in a refrigeration cycle, for filling the temperature-sensing tube of an expansion valve with a mixed gas of refrigerant gas and inert gas.

[0002] The temperature-sensitive tube is generally filled with the same refrigerant gas as the refrigerant used in the refrigeration cycle. However, if you want to change the degree of heating when the expansion valve opens depending on the evaporation pressure of the evaporator, use a mixed gas that is a mixture of a refrigerant gas different from the refrigerant used in the refrigeration cycle and an inert gas at an appropriate pressure ratio. , the temperature-sensitive cylinder is filled.

0003

2. Description of the Related Art FIG. 2 shows a first example of a conventional gas filling device, in which a main valve 5 is connected to a temperature-sensitive tube 51 of an expansion valve.
2, a refrigerant gas supply pipe 53 and an inert gas supply pipe 54 are connected in parallel, and a vacuum pump 55 for emptying the inside of the temperature sensing tube 51 is connected in parallel thereto, and each of the pipes Valves 56, 57, and 58 are connected in the middle. 59 is a pressure regulator for adjusting the filling pressure of inert gas.

When filling the temperature sensing cylinder 51 with a mixed gas of refrigerant gas and inert gas using such a gas filling device, first open the main valve 52 and the vacuum pump valve 58 to fill the inside of the temperature sensing cylinder 51. After creating a vacuum, the vacuum pump valve 58 is closed and the refrigerant gas valve 56 is opened to fill the temperature sensing tube 51 with refrigerant gas.

When the temperature sensing cylinder 51 is completely filled with refrigerant gas, the main valve 52 and the refrigerant gas valve 56 are closed, the vacuum pump valve 58 is opened, and the refrigerant gas in the intermediate pipe is removed.

Next, the vacuum pump valve 58 is closed and the inert gas valve 57 is opened to supply inert gas to the temperature sensing tube 51.
Fill inside. However, this filling time must be instantaneous, approximately 0.5 seconds. Otherwise, the refrigerant gas already filled in the temperature sensing tube 51 will flow backwards and leak out from the inside of the temperature sensing tube 51. When the operation is completed, all the valves 52, 56, 57, and 58 are completely closed to complete the mixed gas filling operation.

FIG. 3 shows a second example of a conventional gas filling device, in which a refrigerant gas supply pipe 53 and an inert gas supply pipe 5 are connected.
A pressure regulator 60, 59 is inserted in each of the refrigerant gas tank 61 and an inert gas tank 62, respectively, to store refrigerant gas and inert gas at predetermined pressures.

[0008]The temperature sensing tube 51 is filled with gas depending on the opening ratio of the mixed gas release valve 63 for releasing the mixed gas into the atmosphere, the refrigerant gas valve 56, and the inert gas valve 57. The mixing ratio of refrigerant gas and inert gas in the mixed gas is kept constant.

[0009]

[Problems to be Solved by the Invention] However, in the first conventional gas filling device described above, the filling operation process is complicated, and it is necessary to control the opening time of the inert gas valve 57 very strictly. However, it has the disadvantage that it is difficult to handle, and the mixing ratio tends to be inaccurate.

Furthermore, in the conventional second gas filling device described above, the mixed gas is released into the atmosphere in order to stabilize the mixing ratio, which is extremely uneconomical and has become a serious problem in recent years. There were drawbacks that led to environmental destruction.

[0011] Therefore, the present invention is easy to handle, does not release refrigerant gas, etc. into the atmosphere, and accurately controls the mixing ratio to transfer a mixed gas of refrigerant gas and inert gas to the temperature sensing cylinder of an expansion valve. The purpose of the present invention is to provide a gas filling device that can fill the gas into the gas.

0012

[Means for Solving the Problems] In order to achieve the above object, a gas filling device for a temperature-sensitive cylinder of an expansion valve according to the present invention has the following features:
A refrigerant tank containing a liquid refrigerant in the lower part and connected to the temperature-sensing cylinder of the expansion valve in the upper part, and the refrigerant tank is heated to a temperature at which the saturated vapor pressure of the refrigerant matches the refrigerant gas pressure filling the temperature-sensing cylinder. a refrigerant tank temperature control means for controlling the temperature of the refrigerant tank; an inert gas tank connected to the refrigerant tank and accommodating an inert gas to be filled in the temperature sensing tube; and an internal pressure of the inert gas tank; a pressure control means for controlling the pressure of the inert gas filled in the temperature sensing tube to be the sum of the refrigerant gas pressure; The present invention is characterized in that a check valve connected between a connecting pipe connecting the gas tank and the refrigerant tank is provided.

[0013]

[Function] In the refrigerant tank, as long as there is refrigerant liquid in the tank, the pressure of the refrigerant gas maintains the saturated vapor pressure at the temperature controlled by the refrigerant tank temperature control means, and the pressure of the inert gas remains constant. , maintain the differential pressure between the refrigerant gas pressure and the internal pressure of the inert gas tank.

[0014]

[Embodiment] An embodiment will be described with reference to the drawings.

In FIG. 1, first and second main valves 3, 4 are interposed in a mixed gas filling pipe 2 connected to a temperature-sensitive cylinder 1 of an expansion valve of a refrigeration cycle. A vacuum pump 5 is connected between 4 and 4.

Therefore, by keeping the vacuum pump valve 6 open and opening and closing the first and second main valves 3 and 4, the inside of the temperature sensing cylinder 1, the inside of the mixed gas filling pipe 2, etc. can be emptied in advance. can do. Then, when filling the temperature sensitive tube 1 with the mixed gas, the vacuum pump valve 6 is kept closed.

Reference numeral 11 denotes a refrigerant tank containing a liquid refrigerant (for example, butane) 100 in its lower part, and the base end of the mixed gas filling pipe 2 is connected above the refrigerant liquid level.

The temperature of the refrigerant tank 11 is controlled by a temperature control device 12 to maintain a desired constant temperature.
The pressure P of the refrigerant gas present above the refrigerant liquid level in the refrigerant tank 11 is the saturated vapor pressure at that temperature. Therefore, the temperature control device 12 controls the temperature of the refrigerant tank 11 to, for example, 25 degrees Celsius so that the saturated vapor pressure of the refrigerant matches the refrigerant gas pressure to be filled into the temperature sensing cylinder 1.

Reference numeral 14 denotes an inert gas tank containing an inert gas (for example, nitrogen), which is supplied from an inert gas cylinder (not shown) and is controlled by a pressure regulating valve 15 interposed in the middle. , inert gas tank 1
4 is maintained at a constant pressure. The pressure Q is the sum of the pressure P of the refrigerant gas in the refrigerant tank 11 and the pressure R of the inert gas to be filled into the temperature sensing cylinder 1, that is, Q=P+R.

The volume of the inert gas tank 14 is very large, for example, about 100 times the volume of the refrigerant tank 11.
A check valve 18 is installed in the middle of the connecting pipe 17 so that gas can flow only from the inert gas tank 14 side to the refrigerant tank 11.
is interposed in the second connecting pipe 20, which is normally closed and opens only when the pressure (P+R) in the refrigerant tank 11 becomes greater than the pressure Q in the inert gas tank 14. A solenoid valve 21 that connects the tanks 11 and 14 is connected.

According to the gas filling device constructed in this way, the pressure P of the refrigerant gas in the refrigerant tank 11 is
As long as the refrigerant liquid 100 exists in the refrigerant tank 11, the saturated vapor pressure at the temperature controlled by the temperature control device 12 is maintained, and the pressure R of the inert gas is equal to the pressure P of the refrigerant gas and the inert gas tank 14. The differential pressure R (R=
Q-P) is maintained.

Therefore, the pressure P in the refrigerant tank 11 can be reduced by simply closing the vacuum pump valve 6 and opening the two main valves 3 and 4 after evacuating the inside of the temperature sensing cylinder 1 and the mixed gas filling pipe 2. Refrigerant gas and inert gas at a pressure (Q-P) are always filled into the temperature sensing cylinder 1 at a stable and accurate mixing ratio.

However, if the temperature control of the refrigerant tank 11 is not stable, such as during the initial stage of filling the mixed gas, the pressure inside the refrigerant tank 11 may become higher than the pressure inside the inert gas tank 14. Sometimes I put it away.

In such a case, the solenoid valve 21 is opened to transfer the mixed gas in the refrigerant tank 11 to the inert gas tank 14.
Send it inside. By lowering the pressure within the refrigerant tank 11 in this way, the pressure of the inert gas in the mixed gas within the refrigerant tank 11 can be lowered to a predetermined pressure (Q-P).

Note that since the volume of the inert gas tank 14 is sufficiently larger than that of the refrigerant tank 11, it can be assumed that the pressure does not increase due to the inflow of the mixed gas as described above. Further, since the pressure of the refrigerant gas in the refrigerant tank 11 is always at the saturated vapor pressure, the refrigerant gas sent to the inert gas tank 14 is returned to the refrigerant tank 11.
Even if the refrigerant gas is fed into the refrigerant tank 11, the refrigerant gas pressure within the refrigerant tank 11 is not affected in any way.

[0026]

[Effects of the Invention] According to the gas filling device for the temperature-sensitive cylinder of the expansion valve of the present invention, by simply controlling the temperature of the refrigerant tank,
Since the refrigerant gas pressure and the inert gas pressure in the refrigerant tank can be maintained at predetermined pressures, the refrigerant gas or the inert gas can be easily handled by simply moving the mixed gas into the temperature sensing cylinder. It has the excellent effect of being able to always fill a temperature-sensitive tube with a mixed gas of refrigerant gas and inert gas at a stable and accurate mixing ratio without releasing any gas into the atmosphere.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an embodiment.

FIG. 2 is a configuration diagram of a first conventional example.

FIG. 3 is a configuration diagram of a second conventional example.

[Explanation of symbols]

1 Temperature sensing cylinder 11 Refrigerant tank 12 Temperature control device 14 Inert gas tank 15 Pressure regulating valve 18 Check valve

Claims (1)

[Claims] Claim 1: A refrigerant tank containing a liquid refrigerant in a lower part and connected to a temperature sensing cylinder of an expansion valve in an upper part, the saturated vapor pressure of the refrigerant being equal to the refrigerant gas pressure filling the temperature sensing cylinder. a refrigerant tank temperature control means for controlling the temperature of the refrigerant tank to a matching temperature; an inert gas tank connected to the refrigerant tank and containing an inert gas to be filled in the temperature sensing cylinder; pressure control means for controlling the internal pressure of the gas tank so that it becomes the sum of the inert gas pressure filled in the temperature sensing tube and the refrigerant gas pressure; A gas filling device for a temperature-sensitive cylinder of an expansion valve, further comprising a check valve connected between a connecting pipe connecting the inert gas tank and the refrigerant tank.