JPS6354986B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in a method and apparatus for injecting refrigerant gas into a cooler.

The conventional method of injecting refrigerant gas into a cooler requires repeated operations of evacuation of the cooler cycle, injection of refrigerant gas for inspection, and evacuation again. This is a process to check for gas leaks in the cooler cycle, but this repetitive operation takes a considerable amount of time, and even if there is no gas leak, even if it is a small amount, the refrigerant gas for inspection is wasted. There is a problem with being thrown away. Furthermore, since the conventional apparatus uses a timer to control the time for evacuation and refrigerant gas injection, it is necessary to check with a pressure gauge whether a predetermined pressure has been reached. During this time, they also use gas detectors to check for gas leaks, so even if other operations are automated, the burden on the workers will not be light. Until now, oil replenishment to the cooler cycle was performed independently from refrigerant gas refilling, but
If oil replenishment could be performed automatically along with refrigerant gas injection, these operations would be further streamlined.

The purpose of the present invention is to provide a method and device for injecting refrigerant gas into a cooler that can automatically detect gas leaks and also replenish oil without requiring repeated steps of evacuation and refrigerant gas injection. It's about doing.

In order to achieve the above object, the method of the present invention includes a first evacuation step in which the internal pressure of the cooler cycle reaches a predetermined degree of vacuum by operating a vacuum pump, and the internal pressure is maintained at a degree of vacuum higher than the degree of vacuum. a second evacuation step in which the action of the vacuum pump is continued in order to reduce the temperature, a leak test step in which the action of the vacuum pump is stopped for a predetermined period of time and an alarm is issued if the internal pressure falls below the degree of vacuum; The method is characterized in that it sequentially includes a first filling step in which gas is injected into the cooler cycle by itself, and a second filling step in which the refrigerant gas is injected by operation of a compressor of the cooler cycle.

Further, the device of the present invention includes a refrigerant tank, an evaporator connected to the refrigerant tank, a fourth electromagnetic shut-off valve connected to the evaporator, and a flow from the fourth solenoid shut-off valve to the second solenoid shut-off valve. The high voltage side circuit leading to the high voltage side connection port,
a low-pressure side circuit branching from a circuit between the second electromagnetic on-off valve and the fourth electromagnetic on-off valve and reaching a low-pressure side connection port;
opening a vacuum pump connected to the high pressure side circuit via a third electromagnetic on-off valve, and a second and third electromagnetic valve;
The first evacuation process control means closes the fourth electromagnetic on-off valve, and the output of the vacuum switch connected to the low-pressure side circuit starts the process, and the second and third electromagnetic valves are opened for the first set time, and the fourth electromagnetic valve is opened/closed. a second evacuation process control means having a evacuation timer for keeping the valve closed; a leak test process control means having a leak test timer and an alarm device for keeping the three electromagnetic on-off valves closed; a first filling process control means for opening the fourth electromagnetic on-off valve after a second set time of the leak test timer; The second filling process control means closes the second electromagnetic on-off valve by the output of a pressure switch connected to the high-pressure side circuit during the first filling process.

The method and apparatus of the present invention will be explained based on embodiments shown in the drawings. As shown in FIG. 1, the refrigerant gas injection device includes a high-pressure side connection port 1 and a low-pressure side connection port 2 that connect to a cooler cycle. A high pressure side pressure gauge 3 and a pressure switch 5 are connected to a conduit from the high pressure side connection port 1 to the second electromagnetic on-off valve 8, and further connected to the suction port of a vacuum pump 10 via a third electromagnetic valve 9.
A low-pressure side pressure gauge 4, a vacuum switch 6, and a first electromagnetic on-off valve 7 are connected to a conduit from the low-pressure side connection port 2 to the electromagnetic on-off valve 8. A pipe line is provided that connects the outlets 12 of the three refrigerant tanks 13, 14, and 15 to the inlet of the honeycomb heater type evaporator 17, which has a relatively small volume, and a fifth electromagnetic on-off valve 16 is inserted in the middle. Tank 13
Allow refrigerant gas to be supplied only from the The outlet of the evaporator 17 is connected to the conduit from the low-pressure side connection port 2 to the electromagnetic on-off valve 8 via the fourth electromagnetic on-off valve 11 . An oil supply circuit in which an oil tank 20, an oil pump 19, a sixth electromagnetic on-off valve 18, and a check valve 25 are connected in series is connected to a conduit from the outlet of the evaporator 17 to the electromagnetic on-off valve 11. Each electromagnetic on-off valve is controlled by an electric circuit including three timers 21, 22, 23 and a manual switch 24, as shown in FIG.

To inject refrigerant gas into the cooler, first, the high pressure side and low pressure side connection ports 1 and 2 are connected to the compressor of the cooler cycle. At this time, if refrigerant gas is present in the cooler cycle, the pressure switch 5 is turned on and the vacuum switch 6 is also turned on at the same time. Then, the electromagnetic on-off valves 7 and 8 are opened, and the gas in the cooler cycle is discharged. Pressure inside the cycle decreases to 2Kg/
When the pressure reaches about cm ² , the pressure switch 5 is turned off and the electromagnetic on-off valve 7 is closed. Initially, if the pressure in the cooler cycle is 2 kg/cm ² or less, this purge step is omitted.

When the pressure switch 5 is turned off, the vacuum switch 6 is turned on, the electromagnetic on-off valve 9 is opened, and the vacuum pump 1 is turned on.
0 operates to evacuate the inside of the cooler cycle. When the degree of vacuum in the cycle reaches approximately 700mmHg, the vacuum switch 6 is turned off and the vacuum timer 21 is activated.
starts. The process from when the pressure switch 5 is turned off until the vacuum switch 6 is also turned off is called a first evacuation process.

The evacuation timer 21 continues to operate for a preset period of time, during which time the vacuum pump 10 increases the degree of vacuum within the cycle. This step is called the second evacuation step. When the timer 21 expires, the electromagnetic on-off valve 9 closes, and the second evacuation process ends.

When the evacuation timer 21 expires, the leak test timer 22 starts and continues its operation for a certain period of time. During this time, the vacuum switch 6 is used to check whether the degree of vacuum in the cycle has decreased. This process is called a leak test process. If there is a gas leak, the degree of vacuum decreases and the vacuum switch 6 is turned on.

When the leak test timer 22 expires, the electromagnetic on-off valves 8 and 11 open, and the refrigerant in the refrigerant tank 13 is heated and vaporized in the evaporator 17, and flows into the cycle.

Due to the inflow of refrigerant gas, the pressure in the cycle increases to 2
When the pressure exceeds about Kg/cm ² , pressure switch 5 is turned on. This process is called the first filling process.

When the pressure switch 5 is turned on, the electromagnetic on-off valve 16 opens, the electromagnetic on-off valve 8 closes, and the engine start lamp 26 lights up. The operator immediately starts the compressor of the cooler and begins a second filling process in which refrigerant gas from all refrigerant tanks 13, 14, and 15 flows into the cycle. When the switch 24 is turned off, the flow of refrigerant gas into the cycle is stopped, but when the switch 24 is turned on again, the flow of refrigerant gas into the cycle is resumed, so an appropriate amount of refrigerant gas can be injected into the cycle. I can do it. The refrigerant gas injection operation is completed with the second filling step, and FIG. 3 shows the change in pressure within the cycle from the initial purge step to the final second filling step. In the figure, D is the purge process, V- is the first vacuuming process, V-
is the second vacuum drawing process, T is the leak test process, C
- indicates the first filling process, and C- indicates the second filling process.

If there is a gas leak in the cycle, the degree of vacuum decreases and the vacuum switch 6 is turned on during the leak test process while the leak test timer 22 is operating, as shown by the broken line in FIG. At the same time, the gas leak indicator lamp 27 and alarm buzzer 28 are activated, and the circuit for the second filling process is cut off. Leak test timer 2
2, the electromagnetic on-off valve 11 opens and a first filling process is performed in which refrigerant gas is injected into the cycle until its pressure reaches about 2 kg/cm ² , and then the injection operation is stopped. Therefore, the operator can use a leak tester or the like to find the gas leak location.

In the present invention, oil replenishment can be performed simultaneously with refrigerant gas injection. At the same time as the engine start lamp 26 lights up, the electromagnetic on-off valve 18
opens, the oil replenishment timer 23 operates, and the oil pump 19 starts. The oil pump 19 sucks oil from the oil tank 20 and pumps it 5 kg/
It is pressurized to about cm ² and flows into the cycle via the electromagnetic on-off valve 18 and check valve 25. By adjusting the operating time of the oil replenishment timer 23, an appropriate amount of oil can be put into the cycle. Switch 5 in all processes including oil supply process,
6, electromagnetic on-off valves 7, 8, 9, 11, 16, 18,
The operations of the timers 21, 22, and 23 are shown in FIG. 4 in the order of steps.

As mentioned above, the method of the present invention can omit the repeated steps of evacuation and refrigerant gas injection, which were conventionally required for leak testing, so the refrigerant gas injection time is shortened and the gas leak location can be fixed. Discovery is also faster. Another advantage is that oil replenishment can be performed at the same time as refrigerant gas injection. The device of the invention not only allows the above method to be carried out automatically, but also because it is based on pressure control.
Compared to conventional control using only a timer, the internal pressure of the cooler cycle reliably reaches a predetermined value. Therefore, accidents that would otherwise occur due to the cooler cycle not being maintained in a predetermined state during refrigerant gas injection work can be prevented.

[Brief explanation of drawings]

Figures 1 and 2 are diagrams showing the basic fluid circuit and sequence electric circuit of a device according to an embodiment of the present invention, respectively, and Figure 3 is a diagram showing changes in the internal pressure of the cooler cycle in the method of the present invention in the order of steps. Figure, 4th
The figure is a diagram showing the operation of the circuit elements of the apparatus of FIGS. 1 and 2 in the order of steps. 1: High pressure side joint, 2: Low pressure side joint, 5: Pressure switch, 6: Vacuum switch, 7:
First electromagnetic on-off valve, 8: Second electromagnetic on-off valve, 10: Vacuum pump, 11: Fourth electromagnetic on-off valve, 13: Refrigerant tank, 17: Evaporator, 18: Sixth electromagnetic on-off valve, 1
9: Oil pump, 21: Vacuuming timer, 2
2: Leak test timer, 23: Oil replenishment timer.

Claims (1)

[Scope of Claims] 1. A first evacuation step in which the internal pressure of the cooler cycle reaches a predetermined degree of vacuum by operating a vacuum pump; a second evacuation step in which the action of the pump is continued; a leak test step in which the action of the vacuum pump is stopped for a predetermined period of time and an alarm is issued if the internal pressure falls below the degree of vacuum; A refrigerant gas injection method comprising, in order, a first filling step of injecting the refrigerant gas into a cooler cycle, and a second filling step of injecting the refrigerant gas by operating a compressor of the cooler cycle. 2. The refrigerant gas injection method according to claim 1, further comprising a purge step in which the refrigerant gas in the cooler cycle is discharged by itself before the first evacuation step. 3. A refrigerant gas injection method according to claim 1 or 2, characterized in that in the second filling step, a predetermined amount of pressurized oil is injected into the cooler cycle together with the refrigerant gas. 4 a refrigerant tank, an evaporator connected to the refrigerant tank, and a fourth electromagnetic shut-off valve connected to the evaporator;
A high-pressure side circuit that runs from the fourth electromagnetic on-off valve to the high-pressure side connection port via the second electromagnetic on-off valve, and a circuit that branches from the circuit between the second electromagnetic on-off valve and the fourth electromagnetic on-off valve to the low-pressure side connection port. a vacuum pump connected to the low-pressure side circuit and the high-pressure side circuit via a third electromagnetic on-off valve, and a first evacuation process control that opens the second and third electromagnetic on-off valves and closes the fourth electromagnetic on-off valve. and a vacuum timer that is started by the output of a vacuum switch connected to the low-pressure side circuit and keeps the second and third electromagnetic on-off valves open and the fourth electromagnetic on-off valve closed for a first set time. A second evacuation process control means and a vacuum evacuation timer that starts when the third electromagnetic on-off valve is closed after the first set time, and is used for leak testing to keep the third electromagnetic on-off valve closed for the second set time. a leak test process control means having a timer and an alarm device; a first filling process control means that opens a fourth electromagnetic on-off valve after a second set time of the leak test timer;
A refrigerant gas injection device comprising a second filling process control means that closes a second electromagnetic on-off valve during the first filling process by the output of a pressure switch connected to a high-pressure side circuit. 5 The discharge port of the oil pump is connected to the circuit from the evaporator to the fourth solenoid shut-off valve via the sixth solenoid shut-off valve, and an oil replenishment timer is provided to control the sixth solenoid shut-off valve. 5. The refrigerant gas injection device according to claim 4, wherein oil can be added together with refrigerant gas in the filling step. 6. A patent claim characterized in that the alarm device is provided with a circuit that controls one or both of the sixth electromagnetic on-off valve and the oil pump, thereby preventing oil replenishment when the vacuum switch is turned on during the leak test process. The refrigerant gas injection device according to item 5.