JPH02154958A - Moisture separator for refrigerant - Google Patents

Abstract

PURPOSE:To separate moisture from the refrigerant having a high moisture content by a method wherein a closed flow path that is connected to a gas refrigerant flow path is cooled to condense the incoming gas refrigerant, the liquid refrigerant condensed is returned to the gas refrigerant flow path through the closed flow path while contacting with the gas refrigerant in the closed flow path. CONSTITUTION:A portion of the gas refrigerant flowing out from a compressor 2 reaches a cooler 14 of a moisture separator 10 from a pipe 11, and is condensed into liquid refrigerant D that enters a water reservoir 17 dripping along the inner wall of a pipe 12. The liquid refrigerant overflowing from the water reservoir 17 falls down along a moisture transfer section 15, comes into contact with the gas refrigerant A, and the moisture is transferred from the liquid refrigerant to the gas refrigerant due to the Henry's law. The moisture concentration of the gas refrigerant increases as the gas refrigerant flows up, and the moisture concentration of the liquid refrigerant decreases as the liquid refrigerant flows down. When the moisture transfer makes progress and the moisture concentration exceeds the moisture saturated concentration during condensation of the gas refrigerant, the excess moisture is separated and retained in the water reservoir 17. Although glass wool 19 catches the moisture having a high surface tension, the liquid refrigerant having a low surface tension does not adhere to the glass wool and flows towards the moisture transfer section 15. Thus, the moisture is separated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a water removal device for reducing moisture contained in a refrigerant.

(Conventional technique) If water is mixed into the refrigerant, it may cause internal corrosion of the metal parts of the equipment that uses the refrigerant, such as the refrigeration cycle.
It may freeze in the expander and cause a decline in cooling performance or failure of the compressor, etc. In particular, in a refrigeration cycle for a car air conditioner, rubber hoses are often used to absorb vibrations, and moisture easily enters the refrigeration cycle through these rubber hoses.

For this reason, Utility Model Application No. 57-50669, Utility Model Application No. 57
Japanese Unexamined Patent Publication No. 54972, Japanese Utility Model Application No. 5'8-55263, and the like propose dehumidification by disposing a desiccant in, for example, a liquid receiver in a refrigeration cycle. Furthermore, Japanese Patent Application Laid-open No. 157462/1984 discloses a method of cooling a refrigerant in a cold trap using liquid nitrogen to freeze water in the refrigerant to reduce the water concentration in the refrigeration cycle.

(Problem to be solved by the invention) However, the method using a desiccant has a limit to its moisture absorption ability, and as moisture is absorbed, the amount of moisture left behind increases. On the other hand, the method using a cold trap requires special additional equipment to obtain extremely low temperatures, and is difficult to apply to equipment with limited space such as an automobile refrigeration cycle.

Therefore, an object of the present invention is to provide a water removal device that has a simple and compact structure and can permanently reduce the water concentration of a refrigerant.

(Means for Achieving the Object) The present invention is based on the so-called Henry's law, which states that the amount of solute (water in this case) contained in a certain amount of solvent (refrigerant in this case) at a constant temperature is proportional to the partial pressure of that solute. Based on this, the gas refrigerant in the equipment is introduced into the stagnation part of the flow, cooled and condensed to create a liquid refrigerant, and the moisture is transferred from this liquid refrigerant to the gas refrigerant in the stagnation part of the flow, and the gas with a high moisture concentration is Excess moisture is precipitated by successively condensing the refrigerant.

According to one feature of the invention, the invention includes a closed channel connected to the gas refrigerant channel, the closed channel being cooled to condense the gas refrigerant entering the closed channel, and contacting the gas refrigerant in the closed channel. A refrigerant water removal device is provided that returns the condensed liquid refrigerant to the gas refrigerant flow path along the closed flow path so as to transfer moisture to the gas refrigerant, and also precipitates water from this high water concentration gas refrigerant during condensation. provided.

(Function) In the above configuration, the closed flow path becomes a stagnation part of the flow,
The flow inside is only due to the condensation of the refrigerant, and the flow rate is very low, and the condensed liquid refrigerant and the inflowing gas refrigerant are almost in equilibrium. Therefore, Henry's law holds true for the moisture concentration of both refrigerants, and moisture transfers from the liquid refrigerant with a low saturated moisture concentration to the gas refrigerant with a high saturated moisture concentration, and when the gas refrigerant with a high moisture concentration subsequently condenses, the liquid refrigerant becomes saturated. Water precipitates in an amount exceeding the concentration. By returning the liquid refrigerant with a low water concentration to the equipment, the water concentration of the refrigerant in the equipment is reduced. In equipment such as refrigeration cycles in which refrigerant circulates during operation, water is gradually removed from the refrigerant by repeating this action.

(Example) Hereinafter, the present invention will be described based on an example shown in the accompanying drawings.

The water removal device of the present invention is based on the operating principle as shown in FIGS. 10a to 10c. That is, when the saturated water concentration of the gas phase refrigerant is higher than that of the liquid phase refrigerant: (1) Gas refrigerant A is introduced into the closed channel B, and is cooled and condensed by the wind C (Fig. 10a, (2) The condensed liquid refrigerant flows down due to gravity, but as mentioned in the previous section, the gas refrigerant and liquid refrigerant are in almost equilibrium state in the same flow path, and Henry's law holds at the interface between the two. , moisture E moves from the liquid refrigerant with a low saturated moisture concentration into the gas refrigerant (Figure JOb, Figure 10c); (3) By continuing to cool and condense the gas refrigerant with a high moisture concentration thus created, The water that can no longer be dissolved in the liquid refrigerant is precipitated, and the liquid refrigerant F is returned to the refrigerant flow from the closed channel (FIG. 10c). Thus,
By sequentially performing the above steps (+1, (2), and (3)), water can be removed and a pure refrigerant can be obtained.

Next, refrigerant R1 in the refrigeration cycle for the car air conditioner,
An example in which water is separated from 2 will be described. As schematically shown in FIG. 1a, the water removal device 10 includes a gas refrigerant pipe 1
A closed flow path 1 consisting of a tube 12 which is erected and whose upper end is closed.
3.

The upper part of this closed flow path 13 is a cooling section 14 that is cooled by outside air.
Below this cooling section 14, a moisture transfer section 15 through which liquid refrigerant flows and a water storage section 17 containing glass wool 16 are provided.

The water removal device 10 is incorporated into a refrigeration cycle for a car air conditioner as shown in FIG. This refrigeration cycle is formed by sequentially connecting a compressor 2, a condenser 3, a receiver 4, an expansion valve 5, and an evaporator 6 through pipes. Omit detailed explanation. The water removal device 10 is a compressor 2
and the condenser 3, and the pipe 12 is connected to the gas refrigerant line 11 via a joint.

The mounting position of the water removal device 110 on the refrigeration cycle is as follows:
From the condenser 3 to the receiver 4 where the refrigerant is in a saturated gas state
For example, the upper part of the receiver tank may be used, and in this case, compared to the above-mentioned mounting position, cooling is advantageous by the degree of superheating of the gas refrigerant. Further, the water removal device 10 may be installed in the low pressure side pipe of the refrigeration cycle, but in this case, whereas the above-mentioned installation on the high pressure side can utilize the cooling air to the condenser 3, the water removal device 10 In order to cool the cooling unit 14, a low temperature source that is lower than the temperature of the low pressure refrigerant is required.

To describe the structure of the water removal device 10 in more detail, the pipe 12 is made of steel, and the inside is coated with phenol or the like for corrosion resistance. As shown in FIG. 3, a synthetic resin pipe 18 is press-fitted into the lower part of the pipe 12, and the water storage part 1
7 is formed.

The pipe 18 has an outer diameter at the lower end larger than the inner diameter of the pipe 12 and an outer diameter above it smaller than the inner diameter of the pipe 12, and the lower end is fixed within the pipe 12 by press-fitting, and the pipe 18 above it is fixed within the pipe 12. A space is defined between the 12 inner walls. This space is filled with glass wool 19, and the inner wall of the pipe 18 constitutes a moisture transfer section 15. The pipe 12 is tightened by a lower nut 20 via a sealing member 21 to a joint provided in the gas refrigerant line 11.

Next, the operation of the water removal device 10 configured as described above will be described.

For convenience of explanation, the temperature of the superheated gaseous refrigerant exiting the compressor 2 is assumed to be 60° C., and the water concentration in the refrigerant at the start of operation of the refrigeration cycle is assumed to be 100 PPM. Further, as can be seen from FIG. 4, the saturated water concentration of refrigerant R-12 at a temperature of 60° C. is 400 ppm in the liquid phase and 1.500 ppm in the gas phase.

During operation of the refrigeration cycle, a portion A of the gas refrigerant leaving the compressor 2 flows into the water removal device 10 through the line 11 and reaches the cooling section 14 through the flow path 13 (FIG. 1a). The gas refrigerant A condenses here to become a liquid refrigerant, flows down the inner wall of the pipe 12, and enters the water storage section 17. As the gas refrigerant continues to condense, the liquid cooling in the water reservoir 17 also increases and overflows from the water reservoir. The overflowing liquid refrigerant falls by gravity along the moisture transfer section 15, and the gas refrigerant A filling the circulating section 15
come into contact with.

In this way, when liquid refrigerant and gas refrigerant coexist,
The moisture concentration Cg of the gas refrigerant in the moisture transfer unit 15 of the water removal device
(ppm) and the water concentration CI (ppm) of the liquid refrigerant, Henry's law is established, and the refrigerant R-12 at 60°C
from the saturated water concentration (see Figure 4) to 1500 ppi/
It becomes constant at 400ppm = 3.75. Therefore, when the liquid refrigerant falls through the moisture transfer section 15, its moisture concentration C
Moisture concentration Cg of at least the interface layer of gas refrigerant A that contacts I and liquid refrigerant (in both cases, at the start of operation of the refrigeration cycle, moisture moves from the liquid refrigerant to the gas refrigerant until 10100 pp becomes the relationship Cg = 3.75 CI) 1b shows this state. As a result, the moisture concentration Cg of the entire gas refrigerant increases as it moves up the moisture transfer section 15.
Cgl when flowing into the water removal device 10 (100++pm)
Cg 2 (1,00+'l
'1 or more). On the other hand, the water concentration C1 of the liquid refrigerant decreases as it descends, and when it flows out of the water removal device 10, the water concentration C1 decreases.
I, (1001111111 or less).

The gas refrigerant that has reached the cooling section 14 has a moisture concentration Cg 2
However, as the movement of moisture progresses and the moisture concentration of the gas refrigerant reaches 400 ppm or more, excess moisture E exceeding the saturated moisture concentration of the liquid refrigerant precipitates during condensation.

The precipitated water E initially adheres to the inner wall of the cooling section 14 due to its surface tension, but as the precipitated water increases, it falls due to gravity and accumulates in the water storage section 17. As described above, this water storage portion 17 is filled with glass wool 19 which has good water wettability and a large interfacial tension when water is depleted. Therefore, water with high surface tension (δ=6.74XL03kg/m
60°C) is attached to the glass wool 19 and captured,
Refrigerant R-12 with extremely low surface tension (δ=0.4X
10-3 kg/m (60°C) flows to the moisture transfer section 15 without adhering to the glass wool 19. In this way, water can be separated from the refrigerant.

Note that by increasing the length of the moisture transfer section 15, the amount of humidification to the gas refrigerant can be increased, and the gas refrigerant can be easily
The water concentration can be higher than ppm. With this configuration, even if the moisture concentration of the refrigerant on the refrigeration cycle side is very low, it is possible to quickly dehumidify.

Next, a water removal device according to another embodiment of the present invention will be described with reference to FIGS. 5 to 8b. The water removal devices of these embodiments may have the same basic structure as the embodiments described above, and only the differences will be briefly described here.

The water removal device 30 shown in FIG. 5 has a cooling section 34 provided with a large number of cooling fins 35. The cooling fins 35 are fixed to the outer periphery of the cooling unit 34 by a known method such as welding or pressure, and improve the heat dissipation of the cooling unit 34. With this configuration, the amount of refrigerant condensed per unit time increases, and the water removal device 3
0 dehumidification rate increases. Note that in order to improve the dehumidification rate, heat transfer within the cooling section 34 may be increased, such as by providing unevenness on the inner wall.

The water removal bag rj 140 shown in FIG. 6a is provided with a spiral step 46 in the moisture transfer section 45 in order to increase the contact time and area between the liquid refrigerant and the gas refrigerant. As shown in FIG. 6b, the step 46 is a helically formed elastic piece of metal or synthetic resin material, which is rolled and inserted into the moisture transfer section 45 and fixed by its repulsive force.

In the water removal device shown in FIG.
A coil spring 56 is attached inside. The liquid refrigerant spirally flows down inside the moisture moving part 55 along the spring 56, as shown by the arrow in the figure. Therefore, the liquid refrigerant and the gas refrigerant are in contact for a relatively long period of time, and moisture is sufficiently transferred.

The water removal device according to the present invention is not limited to the double pipe structure as in the embodiments described so far. For example, as shown in FIG. It is also possible to have a structure in which the pipeline branches. The water removal device 60 of this embodiment is further configured to discharge precipitated water from the water storage section 67 to the outside. Therefore, the lower end of the water storage section 67 is opened and its diameter is expanded, and a transmission plate 63 made of a material with good water permeability and low refrigerant permeability, such as polyFFmide PI, is attached here, and the upper end thereof is Glass wool 66 is stored in the .

The transmission plate 63 is fitted into the enlarged diameter portion at the lower end of the water storage portion 67, and a punch plate 68 with a large number of through holes and a packing 69 are placed under it to swage the lower edge of the enlarged diameter portion inward. is fixed to the water removal device 160.

In the water removal device 60 of this embodiment, the water storage section 67 inside the permeable plate 63 has a relative humidity of 100% due to precipitated water, and has a high internal pressure, so the water vapor partial pressure is high.

On the other hand, since the outside of the permeable plate 63 is exposed to the atmosphere and has a low water vapor partial pressure, the water in the water storage section 67 is discharged to the outside of the water removal device through the permeable plate 63 due to the partial pressure difference.

The water removal device of the present invention can be applied to many facilities that use refrigerants in addition to the above-mentioned refrigeration cycle, and can be used, for example, as a drying tower 70 of a refrigerant production system as shown in FIG. 9a. In this case, as seen in Figure 9b, the drying tower 70
The water removal device may have the same configuration as the above embodiment, but
When the refrigerant exiting the cleaning tower upstream of the drying tower 70 is in a liquid state, it is necessary to provide a heating device 71 upstream of the drying tower 70 to gasify the refrigerant flowing through the pipes. In this embodiment as well, as in the previous embodiment, condensation of the gas refrigerant and transfer of moisture from the liquid refrigerant to the gas refrigerant are performed in the drying tower 70, and moisture is removed from the refrigerant flowing to the downstream stream group. Remove.

In addition, in the above description, although the water storage part of each Example was filled with glass wool, a desiccant may be used instead. In this case, although there is a limit to the moisture absorption capacity of the desiccant as described in the related art, unlike the conventional technology, the water removal device of the present invention performs dehumidification regardless of the moisture absorption capacity of the desiccant. Does not cause a significant decrease in dehumidification capacity.

(Effects of the Invention) As will be clear from the description of the present invention, the present invention has a simple structure in which a closed flow path is provided in the gas refrigerant flow path and this closed flow path is cooled, and the refrigerant is permanently and reliably cooled. It reduces moisture concentration. Therefore, it can be economically used in many facilities that use refrigerants, and can contribute to improving the reliability and life of these facilities.

[Brief explanation of the drawing]

Fig. 1a is a schematic diagram showing a first embodiment of the water removal device of the present invention, Fig. 1b is a diagram for explaining its operation, and Fig. 2 is a refrigeration system incorporating the water removal device of Fig. 1a. A block diagram of the cycle, Figure 3 is a sectional view showing the structure of the water removal device in Figure 1a in detail, Figure 4 is a diagram showing the saturated water concentration of refrigerant R-12, and Figure 5 is a diagram showing the structure of the water removal device of Figure 1a. FIG. 6a is a schematic diagram showing a second embodiment of the water device, FIG. 6a is a schematic diagram further showing a third embodiment, FIG. 6b is a partial sectional view showing an enlarged main part of the third embodiment, and FIG. 7 is a schematic diagram showing a third embodiment. FIG. 8a is a schematic diagram showing a fourth embodiment of the water removal device of the present invention, and FIG. 8b is a perspective view showing components assembled into the fourth embodiment. , FIG. 9a is a block diagram of a refrigerant production system incorporating the water removal device of the present invention, FIG. 9b is a schematic diagram showing the main parts thereof, and FIGS. 10a to 10c are operation diagrams of the water removal device of the present invention. It is an explanatory diagram. In the diagram, 10.30.40.60...Water removal device,
11...Gas refrigerant pipe, 13...Closed channel, 14.34.64...Cooling section, ? 5.
45. 55゜65...Moisture transfer part, 17.6
7...Water storage section, 70...Drying tower, A.
...Gas refrigerant, D...Liquid refrigerant, E...
···moisture.

Claims (3)

[Claims] (1) It includes a closed flow path connected to the gas refrigerant flow path, and is configured to cool the closed flow path to condense the gas refrigerant that has flown in, and to contact the gas refrigerant in the closed flow path to transfer moisture to the gas refrigerant. A water removal device for a refrigerant, characterized in that the liquid refrigerant condensed in water is returned to the gas refrigerant flow path along the closed flow path, and water is precipitated from the gas refrigerant having a high water concentration during condensation. (2) A water removal device for a refrigeration cycle, including a closed flow path consisting of a pipe connected to a high-pressure gas refrigerant flow path between a condenser and a liquid receiver of the refrigeration cycle and closed at an upper end, above the pipe. The part is cooled to condense the gas refrigerant that has entered the closed flow path, and the condensed liquid refrigerant is allowed to flow down the tube and come into contact with the gas refrigerant to transfer moisture to the gas refrigerant while returning it to the refrigeration cycle; A water removal device for a refrigeration cycle, characterized in that moisture is precipitated from the gas refrigerant having a high moisture concentration during condensation, and a water storage portion is provided below the cooling portion in the pipe to capture the precipitated moisture. (3) The refrigerant water removal device according to claim 1 or 2, characterized in that the captured water is transmitted to the atmosphere outside the gas refrigerant flow path by passing through a transmission plate made of polyimide.