JPH11182991A - Piping washing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piping washing device for washing a refrigerant piping efficiently. SOLUTION: This piping washing device is provided with pipings to be washed 71 and 74, a foreign matter separator 10 into which a washing refrigerant flowed into a washing inlet V2 from the pipings to be washed 71 and 74 is introduced, a level sensor for detecting a liquid level in a foreign matter separating means 10, and an inflow stopping valve SV7 provided between the foreign matter separator 10 and the washing inlet V2. In this piping washing device, the liquid level in the foreign matter separator 10 is detected by the level sensor, when the liquid level exceeds a prescribed value, the inflow stopping valve SV7 is closed, when the above liquid level reaches the prescribed value or less, the inflow stopping valve SV7 is opened to allow the washing refrigerant to flow into the foreign matter separator 10 from the washing inlet V2. As a result, the liquid level in the foreign matter separator 10 can be maintained within a prescribed range, and a sufficient foreign matter separating capacity can be maintained always.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe cleaning device for cleaning a refrigerant pipe of an air conditioner, a refrigerator or the like.

[0002]

2. Description of the Related Art From the viewpoint of recent environmental issues, CFC
(Chlorofluorocarbon) or HCFC (hydrochlorofluorocarbon) based refrigerants
It has been proposed to use (hydrofluorocarbon) -based alternative refrigerants.

In order to divert an existing refrigerant pipe when replacing the refrigerant, the inside of the existing refrigerant pipe must be cleaned. That is, lubricating oil or dust is often attached to the inner surface of the existing refrigerant pipe. In particular, in the conventional CFC-based refrigerant, mineral oil was used as the lubricating oil, whereas in the HFC-based refrigerant, synthetic oil was used as the lubricating oil. Therefore, if the mineral oil remained in the existing refrigerant pipe, In the newly installed refrigerant circuit, there is a problem that foreign matter (contamination) is generated, and the throttle mechanism is blocked or the compressor is damaged.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a pipe cleaning apparatus capable of efficiently cleaning a refrigerant pipe.

[0005]

In order to achieve the above object, a pipe cleaning apparatus according to the present invention is connected to a pipe to be cleaned, and circulates a liquid refrigerant through the pipe to be cleaned. A pipe cleaning device for cleaning a pipe, a cleaning inlet connected to the pipe to be cleaned, storing the liquid refrigerant from the pipe to be cleaned, and heating the stored liquid refrigerant to convert the liquid refrigerant into a gas. Foreign matter separating means for discharging the gasified refrigerant and separating foreign matter from the refrigerant, and liquefying the gas refrigerant from the foreign matter separating means and sending the liquefied refrigerant again to the pipe to be cleaned. A sending means, a level sensor for detecting a liquid level in the foreign matter separating means, an introducing pipe connecting the cleaning inlet and the foreign matter separating means, and a liquid level provided in the introducing pipe and detected by the level sensor. Depending on, it is characterized by comprising an inlet gate valve which is opened and closed controlled.

According to the first aspect of the present invention, the cleaning refrigerant flowing from the pipe to be cleaned into the cleaning inlet is introduced into the foreign matter separating means from the introduction pipe. In this foreign matter separating means, the liquid refrigerant from the pipe to be cleaned is stored, the stored liquid refrigerant is heated and gasified, and the gasified refrigerant is discharged to separate foreign substances contained in the cleaning refrigerant. Is done. Then, the cleaning refrigerant in which the foreign matter is separated and cleaned is
The refrigerant is returned to the pipe to be cleaned again by the refrigerant liquefaction sending means. By this repetition, foreign substances adhering to the inner surface of the pipe to be cleaned are washed away with the cleaning refrigerant, and the pipe to be cleaned is cleaned. Here, the foreign matter is something other than the refrigerant for cleaning, and is mainly dust such as oils such as refrigerating machine oil and lubricating oil and oxide films adhered to the inner surface of the existing refrigerant pipe.

In this washing operation, if the flow rate of the washing refrigerant from the washing inlet to the foreign matter separating means is large, the liquid level in the foreign matter separating means rises, and the refrigerant cannot be sufficiently gasified. Then, the foreign matter separating ability becomes insufficient and the foreign matter cannot be separated. Therefore, the liquid level in the foreign matter separating means is detected by the level sensor, and when the liquid level exceeds a predetermined value, the inflow prevention valve is closed. To allow the cleaning refrigerant to flow from the cleaning inlet through the introduction pipe to the foreign matter separating means. As a result, the liquid level in the foreign matter separating means can be maintained within a predetermined range, the foreign matter separating ability can always be sufficiently maintained, and the refrigerant pipe can be efficiently cleaned.

According to a second aspect of the present invention, in the pipe cleaning apparatus according to the first aspect, the determining means determines whether or not the liquid level detected by the level sensor is equal to or higher than a predetermined value. Valve control means for closing the inflow prevention valve for a predetermined time when the liquid level is determined to be equal to or higher than a predetermined value is provided.

According to the second aspect of the present invention, the determining means determines whether or not the liquid level detected by the level sensor is equal to or higher than a predetermined value, and the valve control means determines that the liquid level is equal to or higher than the predetermined value. Is determined, the inflow prevention valve is closed for a predetermined time. Therefore, the liquid level in the foreign matter separating means can be automatically maintained within a predetermined range by the discriminating means and the valve control means, and a shortage of foreign matter separating ability can be avoided.
The refrigerant pipe can be efficiently cleaned. According to a third aspect of the present invention, in the pipe cleaning apparatus according to the first aspect, a determination unit configured to determine whether a liquid level detected by the level sensor is equal to or less than a predetermined value, and Valve control means for opening the inflow prevention valve for a predetermined time when it is determined that it is equal to or less than a predetermined value.
According to the third aspect of the present invention, the determining means determines whether the liquid level detected by the level sensor is equal to or less than a predetermined value, and the valve control means determines that the liquid level is equal to or less than the predetermined value. When it is determined, the inflow prevention valve is opened for a predetermined time. Therefore, it is possible to prevent the shortage of the refrigerant in the foreign matter separating means and realize an efficient pipe cleaning operation. According to a fourth aspect of the present invention, in the pipe cleaning device according to the first aspect, when the liquid level detected by the level sensor is lower than a first predetermined value, the inflow prevention valve is opened, and the first predetermined value is set. Valve control means for closing the inflow prevention valve when the pressure is higher than a second predetermined value higher than the second predetermined value. According to the fourth aspect of the invention, the liquid level in the foreign matter separating means is maintained at a level between a low level (first predetermined value) and a high level (second predetermined value) by the valve control means. Insufficient or excessive refrigerant in the separation means can be avoided, and an efficient pipe cleaning operation can be realized.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

FIG. 1 shows an embodiment of a pipe cleaning apparatus according to the present invention. The pipe cleaning apparatus 1 includes a valve V2 serving as a cleaning inlet and a valve V6 serving as a cleaning outlet.

The pipe cleaning apparatus 1 includes a heat pump circuit 2. The heat pump circuit 2 includes a compressor 3, a sub heat exchanger 5, a four-way switching valve 6, a first transfer heat exchanger 7, a bridge rectifier circuit 8, a temperature-sensitive cylinder type expansion valve 9, a foreign matter separator 10, 2
The transfer heat exchanger 11 and the accumulator 12 are connected in order.

The valve V2 serving as the washing inlet is connected to an inlet pipe 3 provided with a solenoid valve SV7 serving as an inflow prevention valve.
Foreign matter separator 10 that separates foreign matter from the refrigerant via 9
Is connected to the side wall. Then, the foreign matter separator 10
Of the pipe 4 and branch pipes 19 and 2 from the pipe 4
9 is connected to the ceiling of the first and second transfer heat exchangers 7 and 11. Check valves 14,1 are installed in branch pipes 19,29.
5 are provided. The check valves 14 and 15 are first and second
It is in the forward direction toward the transfer heat exchangers 7,11.
Here, the foreign matter separated from the refrigerant by the foreign matter separator 10 is a substance other than the cleaning refrigerant, and mainly includes oils such as refrigerating machine oil and lubricating oil and oxide films adhered to the inner surface of the existing refrigerant pipe. Is garbage.

The first and second transfer heat exchangers 7, 1
The bottom of 1 is connected to the valve V1 and the solenoid valve SV4 by pipes 16 and 17. This piping 16,1
7 is provided with check valves 18 and 20. The check valves 18 and 20 are directed in the forward direction toward the valve V1 and the solenoid valve SV4. And the pipes 16 and 17
It is connected by a communication pipe 21. Further, the valve V1 is connected to a valve V6, and the solenoid valve SV4 is connected to a valve V3. This valve V3 is connected to the refrigerant cylinder 22.

On the other hand, a pipe 31 between the first transfer heat exchanger 7 and the check valve 14 is connected to a solenoid valve SV1 by a pipe 25 via a check valve 23. The pipe 32 between the second transfer heat exchanger 11 and the check valve 15 is connected to the pipe 25 via the check valve 27 and the pipe 30.
Further, the solenoid valve SV1 is connected to a pipe connecting the valve V1 and the valve V6. Check valve 2
3, 27 are in the forward direction toward the connection point P1.

Further, the pipes 31 and 32 are
3, the solenoid valve S passes through the check valves 35 and 36
It is connected to the refrigerant cylinder 22 via V2 and a valve V4. The check valves 35 and 36 are connected to the pipes 31 and 32, respectively.
Toward the front. The branch pipe 33 is connected to a pipe 37 downstream of the solenoid valve SV2, and the pipe 37 is connected to a solenoid valve SV4.
The valve 17 is connected to the pipe 17 between the valve V3 and the valve V3. The pipe 37 has a solenoid valve SV3. Also,
The pipe 33 includes a solenoid valve SV2 and a valve V4.
And a solenoid valve SV1
Is connected to a pipe 25 upstream of This pipe 38 has a solenoid valve SV5.

On the other hand, the foreign matter separator 10 has a heat exchange tube 40 forming a part of the heat pump circuit 2. Further, the foreign matter separator 10 has an upper liquid level confirmation window 41 and a lower liquid level confirmation window 42 fitted on the side wall at a position above the heat exchange tube 40. Further, the foreign matter separator 10 has a filter 43 fixed near the ceiling. And
Both ends of the heat exchange pipe 40 are connected by a bypass pipe 45, and a solenoid valve SV6 is connected to the bypass pipe 45.
Is provided. An oil drain valve V7 is attached to the bottom of the foreign matter separator 10.

The bridge rectifier circuit 8 includes four check valves 50, 51, 52, and 53. The check valve 50 is connected between the first end 8a and the second end 8b. The valve 51 is connected between the second end 8b and the third end 8c. The check valve 52 is connected between the third end 8c and the fourth end 8d, and the check valve 53 is connected between the fourth end 8d and the first end 8a. The check valve 50 is in the forward direction from the first end 8a toward the second end 8b, and the check valve 51 is in the forward direction from the third end 8c toward the second end 8b. The check valve 52 is connected to the third end from the fourth end 8d.
The check valve 53 is in the forward direction from the fourth end 8d toward the first end 8a.

A first end 8a of the bridge rectifier circuit 8 is connected to a heat exchange tube 7A built in the first transfer heat exchanger 7, and a third end 8c is connected to the heat transfer tube built in the second transfer heat exchanger 11. It is connected to the exchange pipe 11A. The second end 8b of the bridge rectifier circuit 8 is connected to the heat exchange pipe 4 of the foreign matter separator 10.
0, and the other end of the heat exchange tube 40 is connected via an expansion valve 9 to a fourth end 8 d of the bridge rectifier circuit 8.

Next, the structure of the foreign matter separator 10 will be further described with reference to FIGS. The foreign matter separator 10 has a cylindrical portion 62 communicating with a side wall 61 at two upper and lower positions. A center shaft 63 is attached to the center of the cylindrical portion 62, and a float 65 slidable up and down along the center axis 63 is attached to the center shaft 63. The cylindrical portion 62, the central shaft 63, the float 65
Constitute the liquid level sensor 66. Fig. 3 (A), (B)
The liquid level sensor 66 moves up and down according to the liquid levels L1 and L2 in the foreign matter separator 10 as shown in FIG.

Next, in the pipe cleaning apparatus having the above structure, when cleaning the pipe, the valve V2 is connected to the valve 72 at one end of the liquid line 71, and the valve 73 at the other end of the liquid line 71 is connected to the other end of the gas line 74. The valve 76 at one end of the gas line 74 is connected to the valve V6.

Next, the cleaning operation of the pipe cleaning apparatus will be described. First, the four-way switching valve 6 of the heat pump circuit 2 is shown in FIG.
When the compressor 3 is operated in the state shown by the solid line, the liquid refrigerant is sent from the compressor 3 to the first transfer heat exchanger 7 via the heat exchanger 5. Then, the first transfer heat exchanger 7 functions as a condenser. The above heat exchanger 5
Plays a role of adjusting the temperature of the refrigerant by releasing a predetermined amount of heat of the refrigerant in a stage preceding the first transfer heat exchanger 7. The heat exchange amount of the heat exchanger 5 can be adjusted by turning on and off the fan 5a.

The refrigerant, whose temperature has dropped a little through the first transfer heat exchanger 7, flows into the heat exchange pipe 40 of the foreign matter separator 10 through the check valve 50 of the bridge rectifier circuit 8, and flows through the introduction pipe 39 from the valve V2. The cleaning refrigerant that has flowed into the foreign matter separator 10 is heated and evaporated.

Next, the refrigerant that has passed through the foreign matter separator 10 and has cooled further passes through the pipe-cylinder expansion valve 9, passes through the check valve 52 of the bridge rectification circuit 8, and passes through the second transfer heat exchanger. 11
Flows into the heat exchange tube 11A. Then, the second transfer heat exchanger 11 functions as an evaporator. In addition, the opening degree of the pipe temperature cylinder type expansion valve 9 changes according to the level of the temperature detected by the pipe temperature pipe 81 attached to the pipe 80, and the refrigerant flowing into the second transfer heat exchanger 11. Is maintained in a predetermined temperature range.

The refrigerant that has passed through the second transfer heat exchanger 11 enters the accumulator 12 via the four-way switching valve 6 and then returns to the compressor 3 in a gaseous state.

With the operation of the heat pump circuit 2, the cleaning refrigerant flowing from the valve V2 at the inlet of the pipe cleaning device 1 first flows into the foreign matter separator 10 via the solenoid valve SV7. Lower heat exchange tube 40
And is separated from oil, and foreign matter is removed by the upper filter 43. Then, the cleaning refrigerant enters a gas state and rises through the pipe 4.

Here, since the second transfer heat exchanger 11 is performing the suction operation and the first transfer heat exchanger 7 is performing the discharge operation, the cleaning refrigerant flows from the pipe 4 to the pipe 29,
Cooled by the heat exchange tube 11A of the second transfer heat exchanger 11,
The gas refrigerant is changed to a liquid refrigerant and stored in the second transfer heat exchanger 11. When the second transfer heat exchanger 11 is filled with the liquid-phase cleaning refrigerant, the pump-side refrigerant that is still cold is sucked into the compressor 3 and the discharge temperature of the compressor 3 decreases. The detected temperature at T2 drops below a predetermined value. Then, the four-way switching valve 6 is switched to the position indicated by the broken line by the control unit (not shown) that has received the signal from the temperature sensor T2.

Then, the refrigerant flow direction of the heat pump circuit 2 is switched, the first transfer heat exchanger 7 performs a cooling operation, and the second transfer heat exchanger 11 performs a heating operation. As a result, the gaseous cleaning refrigerant from the foreign matter separator 10 flows into the first transport heat exchanger 7, is cooled and turned into a liquid refrigerant, and is stored in the first transport heat exchanger 7. On the other hand, in the second transfer heat exchanger 11, the liquid refrigerant stored in the previous cooling operation is heated, pressurized, and sent out to the pipe 17.

Next, when the liquid refrigerant is accumulated in the first transfer heat exchanger 7 and becomes full, a cold refrigerant flows into the compressor 3 from the pipe 26, so that the control unit (not shown) is The four-way switching valve 6 receives a signal from the temperature sensor T2.
To the solid line position.

In the above description, the four-way switching valve 6 is switched when the cooled refrigerant flows into the compressor 3 from the transfer heat exchanger performing the cooling operation and the discharge temperature of the compressor 3 decreases. However, all of the liquid-phase cleaning refrigerant flows out of the transfer heat exchanger that performs the heating operation, and the amount of heat exchange of the refrigerant on the pump circuit side decreases, so that the discharge pressure of the compressor 3 increases. This may be detected by the pressure sensor P2 and the four-way switching valve 6 may be switched. Furthermore,
When the transfer heat exchanger performing the cooling operation is full of the liquid-phase cleaning refrigerant and the internal pressure of the foreign matter separator 10 detected by the low-pressure sensor LPS rises to a saturation pressure corresponding to the discharge temperature of the compressor 3. , The four-way switching valve 6 may be switched.

By the basic operation of the heat pump as described above, the cleaning refrigerant is forcibly circulated through the main cleaning circuit between the valve V2 and the valve V6, so that the gas line 74 and the liquid line 71 as the existing connecting pipes can be cleaned. . Therefore, the existing connecting pipe can be reused, and the laying work can be greatly simplified.

In the above basic operation, the solenoid valves SV1, SV2, SV3, SV4, SV5 are all closed.

As described above, the valve V2
The entered refrigerant passes through the introducing pipe 39 and the foreign matter separator 10 in order, and further passes through the pipes 4, 19, 29, the first and second transfer heat exchangers 7, 11, and the pipes 16, 17, 21. Circulating from the valve V6 to the gas line 74, the liquid line 71,
The gas line 74 is cleaned.

By this cleaning operation, the gas lines 74,
The oil and dust adhering to the inside of the liquid line 71 are washed away with the washing refrigerant. Then, the refrigerant containing the oil and dust is transferred to the valve V
The oil and dust are separated from the above-mentioned refrigerant by circulating from the second through the foreign matter separator 10. Thus, the cleaned refrigerant is circulated again from the valve V6 to the gas line 74 and the liquid line 71, and the cleaning of the gas line 74 and the liquid line 71 is continued.

Referring to the flow chart of FIG. 2, the solenoid valve SV7 is closed and opened according to the amount of liquid in the foreign matter separator 10, and the liquid level in the foreign matter separator 10 is set within a predetermined range. The control operation for maintaining the above will be described. This control operation is executed by, for example, a control unit constituted by a microcomputer.

First, in step S1, it is determined whether or not the amount of liquid in the foreign matter separator 10 is large. This determination is made based on whether the float 65 of the liquid level sensor 66 shown in FIG. 3 is higher or lower than a predetermined upper liquid level. The configuration for detecting whether the float 65 is higher or lower than the upper liquid level may be configured by a limit switch that is turned on and off by the vertical movement of the float 65, or may be configured by an optical sensor. .

If it is determined in step S1 that the amount of liquid in the foreign matter separator 10 is large, the process proceeds to step S2, in which the solenoid valve SV7 serving as an inflow prevention valve is closed, and the process proceeds to step S3. On the other hand, if it is determined in step S1 that the liquid amount in the foreign matter separator 10 is not large, the process proceeds to step S1.
Proceed to 3.

Next, in step S3, the foreign matter separator 10
It is determined whether or not the liquid volume in the inside is small. This determination is made based on whether the float 65 of the liquid level sensor 66 is higher or lower than a predetermined lower liquid level. And this step S
If it is determined in step 3 that the liquid amount in the foreign matter separator 10 is small, the process proceeds to step S4, the solenoid valve SV7 is opened, and the process returns to step S1. On the other hand, if it is determined that the liquid amount in the foreign matter separator 10 is not small, the process proceeds to step S5, and after closing the solenoid valve SV7, a predetermined time (for example, several hours)
It is determined whether or not has elapsed. Solenoid valve SV7
If it is determined that several hours have passed since the closing of
Proceed to 6. The fact that the amount of liquid in the foreign matter separator 10 has not decreased even after several hours have passed since the closing of the solenoid valve SV7 is a state in which oil has accumulated in the foreign matter separator 10. Therefore, in step S6, the valve V7 is opened to drain the oil from the foreign matter separator 10.

On the other hand, if it is determined in step S5 that the predetermined time has not elapsed since the closing of the solenoid valve SV7, the flow returns to step S1.

As described above, in this embodiment, when the liquid amount in the foreign matter separator 10 is larger than the upper limit, the solenoid valve SV7 is closed to stop the flow of the cleaning refrigerant into the foreign matter separator 10, and the heat exchange pipe 40 is closed. Heats and evaporates the washing refrigerant to lower the liquid level. On the other hand, when the liquid amount in the foreign matter separator 10 is smaller than the lower limit, the solenoid valve SV7 is opened to allow the cleaning refrigerant to flow into the foreign matter separator 10. Thus, the liquid amount in the foreign matter separator 10 can be kept within a predetermined range, and the foreign matter separating function of the foreign matter separator 10 can always be normally performed. Further, even if a predetermined time has elapsed since the solenoid valve SV7 was closed, if the liquid amount in the foreign matter separator 10 is within a predetermined range, the foreign matter (oil) of the foreign matter separator 10
Since the removal is performed, foreign matter clogging of the foreign matter separator 10 can be avoided beforehand, and the foreign matter separating function of the foreign matter separator 10 can always be normally performed.

In this embodiment, when recovering the refrigerant, the machine to be recovered (not shown) is connected to the valve V2, the valve V2 is opened, and the valve V6 is closed. And
Open solenoid valve SV4 and valve V3. Then, the refrigerant entering the valve V2 from the machine to be recovered is collected in the refrigerant cylinder 22 through the foreign matter separator 10 and from the first and second transfer heat exchangers 7, 11 via the solenoid valves SV4, V3. Can be.

In this embodiment, at the time of piping cleaning,
When the cleaning refrigerant is insufficient, the solenoid valve SV3
To open the valve V3,
The refrigerant can be supplied to the pipe cleaning path via the solenoid valve SV3, the pipe 33, and the check valves 35 and 36.

When the refrigerant is recovered and the recovery of the refrigerant is difficult due to the high pressure of the refrigerant cylinder 22, the valve V4
, And the solenoid valve SV2 is opened. As a result, the gas refrigerant is sent to the condensing-side transfer heat exchanger 7 or 11, and the internal pressure of the refrigerant cylinder 22 is reduced.

Further, when the refrigerant in the downstream pipe of the valve V6 is self-evaporated when the cleaning refrigerant is recovered after cleaning the pipe, liquid refrigerant may remain in the pipe. In this case, the solenoid valve SV1 is opened, and the pipe 25 from above the first transfer heat exchanger 7 or the second transfer heat exchanger 11 is opened.
The hot gas is introduced into the downstream pipe via the above. As a result, the liquid refrigerant remaining in the downstream pipe is gasified to promote refrigerant recovery.

In this embodiment, a pressure sensor P2 and a temperature sensor T2 are attached to a pipe 90 connecting the compressor 3 and the heat exchanger 5. This pressure sensor P
2 sets the switching timing of the four-way switching valve 6 based on the detected pressure value. When the temperature detected by the temperature sensor T2 exceeds a predetermined value, the compressor 3 is stopped and the compressor 3
Of protection.

In this embodiment, the foreign matter separator 10
Is always located downstream of the first and second transport heat exchangers 7 and 11 that serve as a pressurizer. Furthermore, even if the four-way switching valve 6 is switched by the bridge rectification circuit 8 provided between the first transfer heat exchanger 7 and the second transfer heat exchanger 11,
The temperature-sensitive cylinder type expansion valve 9 can always be located downstream of the foreign matter separator 10. As a result, in the heat pump circuit 2, the temperature of the refrigerant in the foreign matter separator 10 is made lower than the temperature of the refrigerant in the carrier heat exchanger that functions as a pressurizer, and the cleaning refrigerant functions as a decompressor from the foreign matter separator 10. The heat can be smoothly circulated through the transfer heat exchanger.

Further, by opening the solenoid valve SV6 and circulating the refrigerant of the heat pump circuit 2 by bypassing the foreign matter separator 10, the temperature of the foreign matter separator 10 is lowered and the internal pressure of the foreign matter separator 10 is reduced. The refrigerant is lowered and the refrigerant is stored in the foreign matter separator 10. As a result, a pressure difference is generated between the transfer heat exchangers 7, 11 and the foreign matter separator 10, and the refrigerant can flow smoothly from the foreign matter separator 10 to the transfer heat exchanger 7 or 11. Further, in this embodiment, the sight glass 9 fitted on the side wall of the foreign matter separator 10 is used.
At 1,92, the refrigerant level in the foreign matter separator 10 can be visually confirmed.

In this embodiment, the cleaning refrigerant is circulated in the two transfer heat exchangers 7 and 11, but heating (discharge) and cooling (suction) are repeated in one transfer heat exchanger.
The cleaning refrigerant may be intermittently sent to the cleaning circuit. Further, instead of the heat pump circuit 2, the cleaning refrigerant may be circulated by an ordinary transport pump. In the above embodiment, the refrigerant to be recovered and the cleaning refrigerant are CF
Although a conventional refrigerant based on C (chlorofluorocarbon) or HCFC (hydrochlorofluorocarbon) is used, other natural refrigerants may be used.

[0049]

As is apparent from the above description, in the pipe cleaning apparatus according to the first aspect of the present invention, the cleaning refrigerant flowing from the pipe to be cleaned into the cleaning inlet is introduced into the foreign substance separating means from the introducing pipe. In, the stored liquid refrigerant is heated to be gasified and discharged, and foreign substances contained in the cleaning refrigerant are separated.
Then, the cleaning refrigerant from which the foreign matter has been separated and cleaned is returned to the pipe to be cleaned again by the refrigerant liquefaction sending means, so that the foreign substance adhering to the inner surface of the pipe to be cleaned is washed away with the cleaning refrigerant to clean the pipe to be cleaned. In this cleaning operation, according to the present invention, the level sensor detects the liquid level in the foreign matter separating means, and when the liquid level exceeds a predetermined value,
The inflow prevention valve is closed, and when the liquid level falls below a predetermined value, the inflow prevention valve is opened to allow the cleaning refrigerant to flow from the cleaning inlet through the introduction pipe to the foreign matter separating means.
As a result, the liquid level in the foreign matter separating means can be maintained within a predetermined range, the foreign matter separating ability can always be sufficiently maintained, and the refrigerant pipe can be efficiently cleaned. The invention of claim 2 is
The determining means determines whether or not the liquid level detected by the level sensor is equal to or higher than a predetermined value, and the valve control means sets the inflow prevention valve to a predetermined value when the determining means determines that the liquid level is equal to or higher than the predetermined value. Close for hours. Therefore, the liquid level in the foreign matter separating means can be automatically maintained within a predetermined range by the above-mentioned discriminating means and the valve control means. According to a third aspect of the present invention, the determining means determines whether or not the liquid level detected by the level sensor is equal to or less than a predetermined value, and the valve control means determines that the liquid level is equal to or less than the predetermined value. When you do
The inflow prevention valve is opened for a predetermined time. Therefore, it is possible to prevent the shortage of the refrigerant in the foreign matter separating means and realize an efficient pipe cleaning operation. Further, according to the present invention, the liquid level in the foreign matter separating means is maintained at a level between a low level (first predetermined value) and a high level (second predetermined value) by the valve control means, Insufficient or excessive refrigerant in the separation means can be avoided, and an efficient pipe cleaning operation can be realized.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of a pipe cleaning device of the present invention.

FIG. 2 is a flowchart illustrating an operation of the embodiment.

FIG. 3A is a schematic diagram showing a state in which the liquid level is increased in the foreign matter separating means of the embodiment, and FIG. 3B is a state in which the liquid level is reduced in the foreign matter separating means. FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Pipe washing apparatus, 2 ... Heat pump circuit, 3 ... Compressor, 4
... Piping, 5 ... Sub heat exchanger, 6 ... Four-way switching valve, 7 ... First
Transfer heat exchanger, 8 bridge rectifier circuit, 9 expansion valve, 1
0: foreign matter separator, 11: second transfer heat exchanger, 12: accumulator, 22: refrigerant cylinder, 39: introduction pipe, 40
... heat exchange pipe, 41 ... upper liquid level confirmation window, 42 ... lower liquid level confirmation window, 43 ... filter, 45 ... bypass pipe, 61 ...
Side wall, 62: cylindrical portion, 63: central axis, 65: float, 6
6 liquid level sensor, 71 liquid line, 74 gas line.

Claims (4)

[Claims] 1. A pipe cleaning device connected to a pipe to be cleaned (74, 71) for cleaning the inside of the pipe to be cleaned by circulating a liquid refrigerant through the pipe to be cleaned. A cleaning inlet (V2) to be stored, storing the liquid refrigerant from the pipe to be cleaned, heating the stored liquid refrigerant to gasify the liquid refrigerant, discharging the gasified refrigerant, and removing foreign matter from the refrigerant. Foreign matter separating means (10) for liquefying the gas refrigerant from the foreign matter separating means (10) and sending the liquefied refrigerant to the pipe to be cleaned again (2, 7, 11) ), A level sensor (66) for detecting a liquid level in the foreign matter separating means (10), an introduction pipe (39) connecting the washing inlet (V2) and the foreign matter separating means (10), The level sensor (66) is provided in the introduction pipe (39) and is detected. Depending on which liquid level, closing being controlled inlet gate valve (SV7) and the pipe cleaning apparatus characterized by comprising a. 2. The piping cleaning device according to claim 1, wherein said determination means (S1) determines whether or not the liquid level detected by said level sensor (66) is equal to or higher than a predetermined value. Is provided with valve control means (S2, S5, S6) for closing the inflow prevention valve (SV7) for a predetermined time when it is determined that the liquid level is equal to or higher than a predetermined value. apparatus. 3. The piping cleaning device according to claim 1, wherein said determination means (S3) determines whether or not the liquid level detected by said level sensor (66) is equal to or lower than a predetermined value. A valve control means (S4, S1, S2) for opening the inflow prevention valve (SV7) for a predetermined time when it is determined that the liquid level is below a predetermined value. 4. The pipe cleaning device according to claim 1, wherein the inflow prevention valve (SV7) is opened when the liquid level detected by the level sensor (66) is lower than a first predetermined value.
Valve control means (S1, S2) for closing the inflow prevention valve (SV7) when it is higher than a second predetermined value which is higher than the predetermined value.
A pipe cleaning device comprising: (S3, S4).