JP4743906B2 - Refrigeration cycle equipment - Google Patents

Description

The present invention relates to a refrigeration cycle apparatus such as an air conditioner or a refrigerator using a refrigeration cycle, and in particular, a CFC or HCFC refrigerant, a refrigerant using mineral oil as a refrigerator oil, an HFC refrigerant, and an HFC refrigerator oil. It is suitable for the thing exchanged for the thing using.

  CFC-type refrigerant or HCFC-type refrigerant, HFC-type refrigerant that is not compatible with mineral oil from an air conditioner that uses mineral oil as refrigerating machine oil (old machine), and an air-conditioner that uses HFC refrigerating machine oil (new machine) When the connection pipe that connects the indoor unit and the outdoor unit is reused when exchanging it, pollutants (impurities) remain in the reused installation pipe. This impurity is insoluble in the HFC refrigerant used in the new machine, or is a weakly soluble component of refrigerating machine oil (mineral oil, alkylbenzene, etc.) enclosed in the old machine, oxidative degradation reaction product of the refrigerating machine oil, oxidation scale, chlorine compound Etc.

In the method using the existing pipe, the refrigerating machine oil in the new machine deteriorates due to impurities remaining in the connection pipe. Furthermore, components that do not dissolve in the refrigerant may precipitate in the low temperature portion of the refrigeration cycle, clogging the refrigeration cycle, and may significantly impair the reliability of the air conditioner.
Therefore, it is known to perform a cleaning operation for collecting impurities remaining in the connection pipe when using the existing pipe, which is described in Patent Document 1, for example.

JP 2000-9368 A

  In the above prior art, since the foreign matter trapping means is disposed between the user side heat exchanger and the compressor at a position that becomes a gas refrigerant, the refrigeration oil for HFC and the gaseous foreign matter are mixed, and the foreign matter trapping means is I had to pass through several times. Therefore, after replacing the old machine with the new machine, it is necessary to carry out the cleaning operation in the connection pipe for a relatively long time, for example, for about 1 to 2 hours. In other words, the work time for air conditioner replacement work and renewal work was inevitably long.

  An object of the present invention is to efficiently collect impurities remaining in a reused connection pipe, to enable renewal work in a short time, and to improve reliability and performance.

In order to solve the above-mentioned problems, the present invention comprises a compressor, a heat source unit side heat exchanger, a first expansion device, a second expansion device, and a use side heat exchanger sequentially connected by a connection pipe, When changing from a refrigerant that uses mineral oil as a refrigerating machine oil or an HCFC refrigerant to an HFC refrigerant that is not compatible with mineral oil, or that that uses a refrigerating machine oil for HFC that is soluble in the HFC refrigerant In the refrigeration cycle apparatus in which the connection pipe is reused, a receiver that stores liquid refrigerant is provided between the first expansion device and the second expansion device, and the receiver is disposed in the receiver. In addition, mineral oil that is incompatible with the HFC refrigerant passes through the HFC refrigerating machine oil dissolved in the HFC refrigerant, and is a fibrous material that is captured, and is at least either a refrigerant insoluble component or a weakly soluble component with respect to the refrigerant Or A filter to be captured, a member sandwiching the upper and lower sides of the filter, a tip part is set below the filter, two refrigerant introduction / exit pipes through which refrigerant is introduced and provided, and a lower part of the filter, the two A partition plate disposed between the refrigerant inlet and outlet pipes, wherein the two refrigerant inlet and outlet pipes are provided through the filter and a member sandwiching the upper and lower sides of the filter to start the compressor. At least at the time of stopping or at the time of stopping, the first expansion device or the second expansion device on the downstream side of the receiver is fully closed or has a small opening degree close to full closing, so that the refrigerant in the receiver At the same time, the mineral oil is recovered to remove the mineral oil.

In the above configuration, the receiver is manufactured by welding a cap and a body, and it is preferable that a heat insulating material is inserted into a gap between the filter and the receiver .

According to the present invention, a receiver that stores liquid refrigerant is provided between the first expansion device and the second expansion device, and the receiver is disposed in the receiver and dissolved in the HFC-based refrigerant. A filter that captures at least one of a refrigerant insoluble component or a weakly soluble component with respect to the refrigerant, wherein the mineral oil that is incompatible with the HFC refrigerant passes through the refrigeration oil for HFC and is captured. A member that sandwiches the upper and lower sides of the filter, a tip part is set below the filter, two refrigerant introduction / exit pipes through which refrigerant is introduced, and a lower part of the filter, the two refrigerant introduction / extraction pipes And the two refrigerant introduction / exit pipes are provided through the filter and a member sandwiching the upper and lower sides of the filter, and at least when the compressor is started or stopped Any smell , Mineral oil recovered to remove the mineral oil together with the refrigerant in the receiver by a first expansion device or small opening near the second expansion device to the fully closed or fully closed to the downstream side of the receiver Since it is configured as described above, the following effects are obtained.
(B) The mineral oil remaining in the connection pipe is hardly dissolved in the liquid refrigerant and has a higher viscosity than the liquid refrigerant. Therefore, the mineral oil is separated from the liquid refrigerant in the receiver where the liquid refrigerant is present and is caught by the filter. Can be captured by a filter.
(B) The two refrigerant inlet / outlet pipes in the receiver have an end portion set below the filter so as to pass through the filter and a member sandwiching the upper and lower sides of the filter. Since it is fully closed or a small opening close to fully closed, the liquid refrigerant can be recovered in the receiver, and the mixed liquid of liquid refrigerant and mineral oil can be reliably brought into contact with the filter. Insoluble mineral oil can be captured efficiently with a filter.
(C) Due to the effects (A) and (B), according to the present invention, the cleaning operation of the existing piping is not particularly required, and the work time for the renewal work can be shortened.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a cycle system diagram of an air conditioner according to one embodiment, and FIG. 2 shows a cycle system diagram according to another embodiment. 3 and 4 show the configuration of a receiver (impurity recovery device) incorporating a filter for removing refrigerant insoluble components, and FIG. 5 shows mineral oil separation characteristics in the presence of HFC refrigerant, HFC refrigerating machine oil, and mineral oil.

A method for recovering a refrigerant insoluble component remaining in an existing pipe or a weakly soluble component with respect to the refrigerant will be described with reference to FIGS. Hereinafter, the refrigerant insoluble component remaining in the existing piping will be described as mineral oil.
When the air conditioner using CFC or HCFC is aged, replace the air conditioner. First, CFC or HCFC refrigerant is collected, and the outdoor unit 40 and the indoor unit 20 are replaced with those shown in FIG. 1 or FIG. The liquid connection pipe 7 and the gas connection pipe 8 are reused from the old machine. Since the outdoor unit 40 is pre-filled with HFC, the block valves 6 and 9 are closed, and the indoor unit 20, the liquid connection pipe 7 and the gas connection pipe are evacuated, and then the block valve 6 is closed. Perform valve opening and additional filling of HFC.

In the case of cooling operation, the high-temperature and high-pressure gas refrigerant compressed by the compressor 1 is discharged from the compressor 1, and the gas refrigerant flows into the heat source side heat exchanger 3 through the four-way valve 2, where heat exchange is performed. To condense. The condensed and liquefied refrigerant passes through the fully expanded first expansion device 4, and excess refrigerant is stored in the receiver 5, and the remaining is the blocking valve 6, and further passes through the impurity recovery kit 30 in FIG.
Sent to. The sent liquid refrigerant flows into the second expansion device 21, where it is decompressed to a low pressure to become a low pressure two-phase state, and exchanges heat with the use side medium such as air in the use side heat exchanger 22 to evaporate / Gasify. Thereafter, the gas refrigerant returns to the compressor 1 through the blocking valve 9, the four-way valve 2, and the accumulator 10.

  In the case of heating operation, the high-temperature and high-pressure gas refrigerant compressed by the compressor 1 is discharged from the compressor 1 together with the refrigeration oil for HFC, and flows into the use side heat exchanger 22 through the four-way valve 2 and the blocking valve 9. Heat exchange with the use side medium such as air to condense. The condensed and liquefied refrigerant flows into the impurity recovery kit 30, the blocking valve 6, and the receiver 5, is decompressed by the first expansion device 4, and is evaporated by exchanging heat with a heat source medium such as air or water in the heat source unit side heat exchanger 3.・ Gasify. The evaporated and gasified refrigerant returns to the compressor 1 through the four-way valve 2 and the accumulator 8.

Fig. 5 shows the mineral oil when about 10% (= mineral oil amount / (HFC refrigerating machine oil amount + mineral oil amount)) is mixed with HFC refrigerant and HFC refrigerating machine oil. The separation characteristics are shown. The horizontal axis indicates the solubility of the refrigerant in the refrigeration oil (HFC refrigeration oil + mineral oil), where 0% is only the refrigeration oil (HFC refrigeration oil + mineral oil) and 100% is the refrigerant only. The vertical axis represents temperature.
That is, mineral oil hardly dissolves in the HFC refrigerant, while it dissolves in the HFC refrigerating machine oil. And mineral oil is not isolate | separated in the compressor in which many refrigeration oils for HFC exist, but isolate | separates in the liquid connection piping part 7 and receiver 5 in which many liquid refrigerants exist, and the receiver 31b in FIG.
The filter 32a is provided in the impurity recovery kit 30, and the filter 32b is a fiber material having a relatively large number of meshes. The fiber material is made of at least one of polyester and polypropylene.

The liquid refrigerant and the HFC refrigerating machine oil dissolved in the liquid refrigerant are liquids with a remarkably low viscosity, whereas the mineral oil is a liquid having a remarkably higher viscosity than the liquid refrigerant and the HFC refrigerating machine oil dissolved in the liquid refrigerant. Therefore, the liquid refrigerant and the refrigeration oil for HFC dissolved in the liquid refrigerant pass through the filters 32a and 32b, whereas the mineral oil is caught between the fibers of the filters 32a and 32b having a large number of meshes, and then into the fibers by capillary action. Be captured.
Therefore, by arranging the filters 32a and 32b in the liquid connection pipe 7 or the receiver 31b, the mineral oil discharged together with the refrigeration oil for HFC from the compressor 1 is separated in the liquid connection pipe section 7 and the receiver 31b. Only the separated mineral oil can be captured by the filters 32a and 32b.

  When the compressor 1 is in the form of a high-pressure chamber system in which the pressure of the refrigerating machine oil reservoir in the compressor 1 is high, or when an oil separator is disposed in the discharge part of the compressor 1, the compressor 1 or the oil separator The temperature of the refrigeration oil stored in the tank becomes high. On the other hand, the temperature of the liquid connection pipe section 7 and the receivers 5 and 31b is lower than that temperature. The deterioration of the refrigerating machine oil is accelerated as the temperature rises, and the deterioration of the HFC refrigerating machine oil is further promoted as the mixing amount of the mineral oil (deteriorating oil) remaining in the existing pipe increases. By capturing the mineral oil with the liquid connection pipe section 7 and the receiver 31b, which are cooler than the inside or the oil separator, it is possible to suppress the deterioration of the refrigeration oil for HFC.

  Further, in order to capture the mineral oil in the filters 32a and 32b, the filters 32a and 32b need to be in contact with the mineral oil. Therefore, when the compressor 1 is started and when the compressor is stopped, the expansion device on the downstream side of the impurity recovery container 31a or the receiver 31b (21a, 21b in the cooling operation, 4 in the heating operation) is completely removed. The refrigerant is recovered in the impurity recovery container 31a or the receiver 31b by operating at a small opening close to or fully closed. As a result, the filter 32a, 32b can be contacted with the mixed liquid of the HFC refrigerant, HFC refrigerating machine oil, and mineral oil, so only the mineral oil is separated in the impurity recovery container 31a and the receiver 31b. Only mineral oil can be captured.

  Furthermore, the amount of mineral oil captured by the filters 32a and 32b decreases as the flow velocity with respect to the filters 32a and 32b increases. This is because the mineral oil once captured by the filters 32a and 32b is pushed out of the filters 32a and 32b by the fluid force of the refrigerant. And the liquid mixture becomes so near that the pipe | tube front-end | tip part of the refrigerant | coolant inlet / outlet pipe | tube 34a, 34b, 35a, 35b which introduce | transduces the liquid mixture of HFC type refrigerant | coolant, HFC refrigerating machine oil, and mineral oil in the impurity collection container 31a or the receiver 31b. Since the inflow rate of the HFC refrigerant, HFC refrigerating machine oil and mineral oil introduced into the impurity recovery container 31a or the receiver 31b passes through the filters 32a and 32b with the pipe tip portion facing downward, Derived from the impurity recovery container 31a or the receiver 31b. Thereby, it can suppress that the mineral oil introduce | transduced in the impurity collection | recovery container 31a or the receiver 31b is derived | led-out, without passing filter 32a, 32b.

  Further, the refrigerant introduction / exit pipes 34a, 34b, 35a, 35b introduced into the impurity collection container 31a or the receiver 31b and the filters 32a, 32b are secured, and the refrigerant introduction / exhaust pipe is provided in the impurity collection container 31a or the receiver 31b. It is desirable to arrange partition plates 33a and 33b between 34a, 34b, 35a and 35b.

Then filter 32a for removing refrigerant insoluble components incorporated in the receiver 31b shown in impurity collection set 30a impurity collecting container 31a or Figure 2 of disposing the liquid connection pipe shown in FIG. 1, the installation method of 32b, FIG. 3, FIG. 4 will be described.
As shown in FIGS. 3 and 4, during manufacture of the receiver (impurity collecting container), after interposing a filter 32c, and 32d in punching metal 361c, 3 61d, 36 2, the cap 371c, 37 2c, 3 7 2 d and carried out by welding body 38c, and 38d. At that time, the temperature of the inner wall surfaces of the bodies 3 8 c and 3 8 d exceeds the maximum operating temperature of the filters 32 c and 32 d. For this reason , if the filters 32c and 32d are in contact with the inner wall surfaces of the bodies 38c and 38d, the filters 32c and 32d are deteriorated by heat, and the refrigerant insoluble component cannot be captured. Its in the present embodiment in this, as shown in FIG. 3, the temperature of the filter 32c is provided a predetermined distance Δd between the body 38c and the filter 32c so that the maximum use temperature or less. Alternatively, as shown in FIG. 4, a heat insulating material 39d such as ceramic or glass having low thermal conductivity is inserted to suppress the temperature of the inner wall surface of the body 38d from being transmitted to the filter 32d.

The cycle system diagram which shows one embodiment by this invention. The cycle system diagram which shows other embodiment by this invention. Sectional drawing of the receiver (impurity collection | recovery apparatus) by one Embodiment. Sectional drawing of the receiver (impurity collection | recovery apparatus) by other embodiment. Figure. The graph which shows the mineral oil separation characteristic in the presence of HFC type refrigerant, HFC refrigerating machine oil, and mineral oil.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Four way valve, 3 ... Heat source machine side heat exchanger, 4 ... 1st expansion device, 21a, 21b ... 2nd expansion device, 5, 31b ... Receiver, 6, 9 ... Stop valve, DESCRIPTION OF SYMBOLS 7 ... Liquid connection piping, 8 ... Gas connection piping, 10 ... Accumulator, 20a, 20b ... Indoor unit, 22a, 22b ... Usage side heat exchanger, 30a ... Impurity collection kit, 31a ... Impurity collection container, 32a, 32b, 32c , 32d ... filter, 33a, 33b, 33c, 33d ... partition plate, 34a, 34b, 34c, 34d , 34e, 35a, 35b, 35c, 35d ... refrigerant inlet and outlet pipes, 361c, 361d, 362 ... punching metal, 371 c , 3 72c, 372d ... cap, 38c, 38d ... body, 39d ... insulation material, 40a, 40b ... outdoor unit.

Claims (2)

Compressor, heat source side heat exchanger, first expansion device, second expansion device, utilization side heat exchanger are connected in order by connecting piping, CFC refrigerant or HCFC refrigerant and mineral oil as refrigerating machine oil Refrigeration cycle equipment that reuses the above-mentioned connecting pipes when replacing the ones using HFC refrigerants that are not compatible with mineral oil and ones that use refrigeration oils for HFCs that are soluble in HFC refrigerants In
Providing a receiver for storing liquid refrigerant between the first expansion device and the second expansion device;
The receiver is
The mineral oil that is disposed in the receiver and that is incompatible with the HFC refrigerant passes through the HFC refrigerating machine oil dissolved in the HFC refrigerant, and is captured by the fibrous material. A filter that captures at least one of the weakly soluble components;
Members sandwiching the top and bottom of the filter;
Two refrigerant introduction / exit pipes, each of which has a distal end set below the filter and into which refrigerant is introduced;
A partition plate provided at a lower portion of the filter and disposed between the two refrigerant introduction / exit pipes;
The two refrigerant inlet / outlet pipes are provided through the filter and a member sandwiching the upper and lower sides of the filter,
By setting the first expansion device or the second expansion device on the downstream side of the receiver to be fully closed or a small opening close to full closure at least at the time of starting or stopping the compressor A refrigeration cycle apparatus that collects mineral oil together with a refrigerant in the receiver to remove the mineral oil.   2. The refrigeration cycle apparatus according to claim 1, wherein the receiver is manufactured by welding a cap and a body, and a heat insulating material is inserted into a gap between the filter and the receiver.

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