JPH0694974B2 - Refrigerant recovery device - Google Patents

Description

The present invention relates to a refrigerant recovery device for recovering a refrigerant from a refrigeration cycle.

[Prior Art] Conventionally, there is a technology of recovering a refrigerant from a refrigeration cycle applied to an air conditioner of a vehicle and various refrigerators by using a refrigeration apparatus (see Japanese Patent Laid-Open No. 57-91305).

In this conventional technique, a container for recovering a refrigerant is connected to a recovery refrigeration cycle, and the container is cooled by a refrigerating device to condense and recover the refrigerant flowing into the container.

[Problems to be Solved by the Invention] However, for example, in a refrigeration cycle for a vehicle, since each functional component forming the refrigeration cycle is connected by a pipe serving as a refrigerant passage and a rubber hose, long-term use In that case, air may enter the cycle from the hose.

Therefore, during the refrigerant recovery, when the air in the refrigeration cycle flows into the refrigerant recovery container, the pressure inside the container becomes higher than the saturation pressure by the partial pressure of air, and even if the refrigerating device cools the refrigerant recovery container, Since the air that has flowed into the container does not condense or liquefy, the pressure inside the container does not decrease.

Therefore, there is a problem that the recovery time of the refrigerant is extended and the recovery becomes impossible when the amount of air flowing into the container is large.

The present invention has been made based on the above circumstances, and an object thereof is to recover a refrigerant without significantly increasing the recovery time even when air is mixed in the refrigeration cycle for recovery. It is to provide a refrigerant recovery device that can perform.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a refrigerant recovery container that is connectable to a refrigerant flow path of a refrigeration cycle for recovery, and a cooling means that cools the refrigerant recovery container. In the refrigerant recovery apparatus including the above, the refrigerant recovery container employs, as a technical means, an air venting means for releasing the air that has flowed in from the recovery target refrigeration cycle at the time of refrigerant recovery.

[Operation and Effect of the Invention] According to the present invention having the above-described configuration, since the refrigerant recovery container is provided with the air venting means, the air flowing into the container from the recovery refrigeration cycle for recovery is released through the air venting means. be able to.

Therefore, by bleeding air during the recovery of the refrigerant, the pressure in the refrigerant recovery container can be lowered, and then the refrigerant can be recovered again.

As a result, even if the amount of air that has flowed into the refrigerant recovery container is large, the recovery is not impossible and the recovery time is not significantly extended.

[Embodiment] Next, a refrigerant recovery device of the present invention will be described based on an embodiment shown in the drawings.

FIG. 1 is an overall configuration diagram of a refrigerant recovery device connected to a recovery refrigeration cycle.

The refrigerant recovery device 1 of the present embodiment is provided with a refrigeration cycle 2 for recovery.
Refrigerant recovery container 3 connected to the refrigerant flow path of Refrigerator 4, and refrigeration cycle 4 as cooling means for cooling the refrigerant recovery container 3
With.

The refrigeration cycle for recovery 2 is used, for example, in a vehicle air conditioner, and includes a refrigerant compressor 5, a refrigerant condenser 6, a receiver 7, a pressure reducing device 8, and a refrigerant evaporator 9, and a refrigerant. It has a well-known structure in which the above functional parts are connected in an annular shape by a pipe 10.

The refrigerant recovery container 3 is, for example, a cylindrical container made of aluminum, and an air vent pipe 11 communicating with the inside of the container 3 is attached to the upper end surface of the container 3.

The tip of this air bleeding pipe 11 is opened to the atmosphere,
A diaphragm 11a is formed in the middle.

Further, the air bleeding pipe 11 is provided with a relief valve 13 which is energized and controlled by a control circuit (see FIG. 3) 12 described later on the upstream side of the throttle 11a (on the side of the container 3).

The air bleeding means of the present invention is composed of the air bleeding pipe 11 and the relief valve 13.

The refrigerant recovery container 3 is connected to a high pressure side service valve 5a and a low pressure side service valve 5b provided in the refrigerant compressor 5 of the recovery refrigeration cycle 2 by a charging hose 14.

A recovery tank 15 for storing the recovered liquid refrigerant is liquid-tightly connected to the bottom of the refrigerant recovery container 3.

As shown in FIG. 2, the refrigerant recovery container 3 and the recovery tank 15 have a tip end (lower end in FIG. 2) of the connecting pipe 3a provided at the bottom of the refrigerant recovery container 3 and an upper part of the recovery tank 15. Liquid-tightly inserted into the inflow port 15a provided in the connection pipe 3a, which is assembled to the end of the connection pipe 3a, is connected to the outer periphery of the inflow port 15a by screwing.

It should be noted that the inside of the refrigerant recovery container 3 and the inside of the recovery tank 15 are evacuated in advance (or may be filled with a small amount of refrigerant gas) before the recovery of the refrigerant.

The charging hose 14 and the connecting pipe 3a described above are connected to the solenoid valve 16 whose energization is controlled by the control circuit 12 and
17 are provided.

The refrigeration cycle 4 is a well-known accumulator cycle in which the functional components of the refrigerant compressor 18, the refrigerant condenser 19, the fixed throttle 20, the refrigerant evaporator 21, and the accumulator 22 are annularly connected by a refrigerant pipe 23. The numeral 24 shown in FIG. 1 is a cooling fan that blows air to the refrigerant condenser 19.

The refrigerant evaporator 21 of the present embodiment is configured by spirally winding the refrigerant flow passage 21a around the refrigerant recovery container 3, and is provided in thermal contact with the refrigerant recovery container 3.

A temperature sensor 25 for detecting the surface temperature of the refrigerant recovery container 3 is provided below the refrigerant recovery container 3, and a temperature sensor for detecting the temperature of the refrigerant flowing out of the refrigerant evaporator 21 is provided at the outlet pipe of the refrigerant evaporator 21. 26 are provided. Note that the temperature sensor
The place where 26 is provided is not limited to the outlet pipe, and may be provided in the inlet pipe of the refrigerant evaporator 21.

The temperature sensor 25 and the temperature sensor 26 are differential temperature switches.
Connected to 27.

The differential temperature switch 27 is used when the difference between the temperature T1 detected by the temperature sensor 25 and the temperature T2 detected by the temperature sensor 26 is 10 ° C or less (T1-T2
Turns on at <10 ℃).

Further, on the upper end surface of the refrigerant recovery container 3, the same refrigerant gas as the refrigerant enclosed in the refrigeration cycle 4 (for example, R12 refrigerant)
The temperature sensitive cylinder 28 enclosing the
The pressure change in the temperature sensitive tube 28 is changed by the differential pressure switch via the thin tube 29.
Introduced on one side of 30.

The pressure in the refrigerant recovery container 3 is introduced to the other side of the differential pressure switch 30 via the thin tube 31.

The differential pressure switch 30 determines whether or not air has flown into the refrigerant recovery container 3, and is turned on when the pressure inside the refrigerant recovery container 3 becomes higher than the pressure inside the temperature sensing cylinder 28. To do.

As shown in the electric circuit diagram of FIG. 3, the control circuit 12 operates by turning on the main switch 32, and based on the output signals of the differential temperature switch 27 and the differential pressure switch 30, the relay coil
Energization control of the relief valve 13 and the solenoid valves 16 and 17 is performed via the 33, 34 and 35 and the relay switches 33a, 34a and 35a. The relief valve 13 and the solenoid valves 16 and 17 are opened by being energized. The number 36 shown in FIG. 3 is a rectifier circuit that converts alternating current into direct current.

Here, the operation of the air detection control by the control circuit 12
A description will be given based on the flowchart shown in the figure.

In step S1, it is determined whether the differential temperature switch 27 is turned on.

If the decision result in the step S1 is NO, the step S1 is repeated.

If the decision result in the step S1 is YES, a step S2 decides whether or not the differential pressure switch 30 is turned on.

If the decision result in the step S2 is NO, the process ends as it is.

If the decision result in the step S2 is YES, the energization of the solenoid valves 16, 17 is stopped in the step S3, and the process proceeds to the step S4.

The relief valve 13 is energized in step S4, and step S5
Go to.

After 10 seconds have elapsed in step S5, the relief valve is released in step S6.
The energization to 13 is stopped and the solenoid valves 16 and 17 are energized.

Next, the operation of the refrigerant recovery device 1 of this embodiment will be described.

When the main switch 32 is turned on, the solenoid valves 16 and 17 are energized, and the refrigerant gas flows from the refrigeration cycle for recovery 2 into the refrigerant recovery container 3 that has been evacuated in advance.

The refrigerant gas flowing into the refrigerant recovery container 3 is heat-exchanged with the low-temperature low-pressure refrigerant supplied to the refrigerant evaporator 21 by the activation of the refrigeration cycle 4, condensed and liquefied to sequentially recover the recovery tank 15
And is stored in the recovery tank 15.

During the recovery of the refrigerant, when the air mixed in the to-be-collected refrigeration cycle 2 flows into the refrigerant recovery container 3,
The pressure in the container 3 becomes higher than the saturation pressure with respect to the temperature of the container 3 by the partial pressure of air.

Therefore, as the amount of air in the container 3 increases, the amount of recovered refrigerant decreases, so the refrigerating capacity of the refrigerant evaporator 21 becomes excessive, and the refrigerant recovery container 3 is cooled by the low temperature refrigerant flowing through the refrigerant passage 21a. To be cooled.

As a result, the temperature T1 detected by the temperature sensor 25 decreases, and when the temperature difference from the temperature T2 detected by the temperature sensor 26 becomes 10 ° C. or less, the differential temperature switch 27 is turned on.

The differential temperature switch 27 measures the timing of air detection by the differential pressure switch 30 so that the differential pressure switch 30 does not turn on with a small amount of air when air flows into the refrigerant recovery container 3. .

When the differential temperature switch 27 is turned on, the air detection control by the control circuit 12 is performed. Since the air is flowing into the refrigerant recovery container 3, the differential pressure switch 30 is turned on and the solenoid valves 16 and 17 are turned on.
Is stopped, and air is trapped in the refrigerant recovery container 3.

After that, the relief valve 13 is energized and opened, and the air in the container 3 is discharged through the air bleeding pipe 11.

After bleeding air for 10 seconds, the relief valve 13 is closed, the solenoid valves 16 and 17 are opened, and the refrigerant is collected again.

When the relief valve 13 is opened, the refrigerant gas collected in the container 3 is also released together with the air, but as shown in FIG. Absolute amount is 10g or less, which is not a problem. In addition, in FIG. 5, the solid line graph shows the measurement result when air does not flow into the refrigerant recovery container 3, and the broken line graph shows the measurement result when air flows into the refrigerant recovery container 3. Indicates.

In this way, by bleeding air during refrigerant recovery,
Again, the refrigerant gas can be introduced into the refrigerant recovery container 3. As a result, the recovery of the refrigerant does not occur, and the recovery time does not significantly increase.

FIG. 6 shows a second embodiment of the present invention.

In this embodiment, in order to effectively release the air mixed in the refrigerant recovery container 3, the air vent pipe 11 provided on the upper end surface of the refrigerant recovery container 3 is bent as shown in FIG. Instead, it is opened upward, and a refrigerant recovery port 3c for recovering the refrigerant via the charging hose 14 is provided in the lower portion of the refrigerant recovery container 3.

When bleeding air from the refrigerant recovery container 3, only the solenoid valve 17 is closed, the solenoid valve 16 is left open, and the relief valve 13 is opened.

As a result, at the time of bleeding air, the gas refrigerant recovered from the to-be-recovered refrigeration cycle 2 flows from the lower part inside the refrigerant recovery container 3 through the recovery port 3c, so that the upper part inside the refrigerant recovery container 3 The accumulated air is pushed out and effective air bleeding is possible.

The timing for bleeding air is based on the operation of the differential temperature switch 27, as in the first embodiment. Alternatively, the relief valve 13 may be energized to start bleeding after a predetermined time (for example, 3 minutes) from the start of collecting the refrigerant.

(Modification) A modification of the connection structure between the refrigerant recovery container 3 and the recovery tank 15 will be described with reference to FIG.

By pushing up the recovery tank 15 with a set lever (not shown), the refrigerant recovery container 3 and the recovery tank 15 are sealed. Then, the shaft 37 attached to the connecting portion between the refrigerant recovery container 3 and the recovery tank 15 is rotated. As a result, an oval cam 38 that is integrally connected to the shaft 37.
Is rotated and the respective valve elements 39 and 40 are pushed open, so that the refrigerant recovery container 3 and the recovery tank 15 are communicated with each other.

In the above embodiment, the differential pressure switch 30 is provided to detect air, but it is not always necessary to provide the differential pressure switch 30.
When the differential temperature switch 27 is turned on, the relief valve 13, solenoid valve
It is also possible to energize 16 and 17 to remove air.

In this case, when the air does not flow into the refrigerant recovery container 3, only the refrigerant gas is released, but as shown in the embodiment, the absolute release amount of the refrigerant gas is 10%.
Since it is less than g, it does not matter.

Also, when bleeding air, the control circuit 12 controls the relief valve.
13, the solenoid valves 16 and 17 are energized, but the operator may be informed of the timing of air bleeding by lighting a buzzer or a lamp, and each valve may be manually opened / closed.

Although the refrigerating cycle 4 is shown as the cooling means of the refrigerant recovery container 3, the refrigerant recovery container may be cooled by a cold storage type cooling pack.

Although the recovery tank 15 is connected to the refrigerant recovery container 3 and used, the recovery tank 15 does not necessarily have to be used, and the liquid refrigerant may be recovered in the refrigerant recovery container 3.

[Brief description of drawings]

1 to 5 show an embodiment of the present invention.
FIG. 1 is an overall configuration diagram of a refrigerant recovery device connected to a recovery refrigeration cycle, FIG. 2 is a state diagram showing a connection structure between a refrigerant recovery container and a recovery tank, and FIG. 3 is an electric circuit of the refrigerant recovery device. FIG. 4 is a flow chart showing the operation of the control circuit, FIG. 5 is a graph showing the relationship between the outside air temperature and the amount of refrigerant gas released, and FIG. 6 shows the second embodiment of the present invention. FIG. 7 is a sectional view showing a connection state of the refrigerant recovery container and each pipe, and FIG. 7 is a state diagram showing a modified example of the connection structure of the refrigerant recovery container and the recovery tank. In the figure, 1 ... Refrigerant recovery device 2 ... Refrigeration cycle to be recovered 3 ... Refrigerant recovery container 4 ... Refrigeration cycle (cooling means) 11 ... Air bleeding pipe (air bleeding means) 13 ... Relief valve (air bleeding means)

Claims (1)

[Claims] 1. A refrigerant recovery device comprising a refrigerant recovery container that is provided so as to be connectable to a refrigerant flow path of a refrigeration cycle for recovery, and a cooling means that cools the refrigerant recovery container. A refrigerant recovery device, characterized in that air recovery means is provided for releasing the air that has flowed in from the recovery-use refrigeration cycle during the recovery of the refrigerant.