JPH07332810A - Oil mist separator for refrigeration equipment - Google Patents

Abstract

(57) [Summary] [Objective] Oil mist components having low viscosity in a high temperature state in a refrigerant gas supplied from a compressor can be cooled to increase viscosity and improve separation efficiency. [Structure] The demister in the oil mist separator 10 has a heat exchanger structure capable of exchanging heat to increase the viscosity of the oil mist component to prevent the formation of a liquid film on the inner wall surface of the oil mist separator container and the evaporation of oil. By suppressing it, the amount of oil mist component mixed with the refrigerant gas and flowing into the cycle was greatly reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of an oil mist separator for refrigeration equipment.

[0002]

2. Description of the Related Art As an oil mist separator for separating an oil mist component in a refrigerant gas of a refrigerating device, for example, a gas refrigerant is made to collide with a collision plate provided in an oil mist separator casing having a predetermined volume space or a demister. There is proposed a device using a wire mesh-shaped collision plate called as, but in such a simple form, the refrigerant gas and the oil mist component are not necessarily efficiently separated so that only the refrigerant gas flows out from the outlet pipe. However, there was a problem that the separation efficiency was low.

In order to solve such a problem, for example, the one disclosed in Japanese Utility Model Publication No. 5-22246 discloses:
As shown in FIG. 7, an inlet pipe 32 for the refrigerant gas, which vertically opposes, is provided close to the upper surface of the demister 40 made of a wire mesh provided in the casing 31 via the shield plate 36, and inertia of the oil mist and the refrigerant gas is provided. We are trying to improve the separation efficiency by using the difference in force to prevent the re-scattering of the oil mist component which is too large.

[0004]

However, in the structure of the conventional oil separator 30, the oil and oil mist components remaining on the surrounding shield plate 36 without passing through the demister 40 are in a high temperature state. Due to the influence of the refrigerant gas having a low viscosity and convection in the oil mist separator casing 1, a thin film flows on the inner wall surface of the oil mist separator casing 1 as shown by the phantom line in FIG. There is a problem that it reaches 33 parts and flows out together with the discharged refrigerant gas. Further, since the refrigerant oil has a high vapor pressure in a high temperature state, it also evaporates even on the liquid chamber or on the inner wall surface of the oil mist separator casing 1 and then becomes a fine mist to flow out.

When the oil cannot be sufficiently separated by the oil mist separator and the oil flows into the refrigeration system in this way, not only the pressure loss in the refrigerant pipe becomes large but also the heat of the evaporator and the condenser is reduced. It is feared that the heat transfer coefficient of evaporation and condensation in the exchanger part will be significantly reduced, resulting in a reduction in efficiency and capacity of the equipment.

According to the present invention, the demister section in the oil mist separator is configured to be capable of heat exchange, and the viscosity of the oil mist component is increased, thereby forming an oil liquid film on the inner wall surface of the oil mist separator container and evaporating the oil. It is an object of the present invention to suppress it as much as possible so that the amount of oil mist components flowing into the refrigeration cycle can be sufficiently reduced.

[0007]

In order to achieve the above object, the present invention comprises the following problem solving means.

That is, the oil mist separator for a refrigerating apparatus of the present invention is, for example, as shown in FIGS. 1 to 5, an oil mist separator casing 1 to which a high temperature refrigerant gas containing an oil mist component from a compressor 11 is supplied. A demister having a mesh structure for separating oil mist components is provided therein, and the demister is formed in a heat exchanger structure.

As the heat exchanger structure forming the demister, for example, a mesh fin heat exchanger structure 5 in which a plurality of mesh fins 5b, 5b ... Are laminated on both sides of the heat transfer tube 5a is adopted.

The demister having the above heat exchanger structure is incorporated in the refrigerating circuit of the refrigerating apparatus and uses the low temperature refrigerant from the evaporator 14 to the compressor 11 as the heat exchanging refrigerant. .

Then, in that case, the refrigeration circuit is incorporated into the refrigeration system by using the main refrigerant pipe 23 from the evaporator 14 to the compressor 11 or in parallel with the main refrigerant pipe 23. This is done using the installed bypass refrigerant pipe 24. Further, when the bypass refrigerant pipe 24 is incorporated using the bypass refrigerant pipe 24,
A flow rate adjusting means 8 for adjusting the inflow amount of the low temperature refrigerant is provided midway.

[0012]

The oil mist separator for a refrigerating machine according to the present invention has the following actions corresponding to the above-mentioned structure.

That is, as described above, in the oil mist separator for a refrigerating apparatus of the present invention, the oil mist component is first placed in the oil mist separator casing 1 to which the high-temperature refrigerant gas containing the oil mist component is supplied from the compressor 11. A demister having a mesh structure for separation is provided, and the demister has a heat exchanger structure. Therefore, the high temperature oil mist component introduced into the oil mist separator casing 1 is appropriately cooled in the demister section to have a high viscosity, which makes it difficult to form an oil liquid film in the oil mist separator casing 1 and also evaporates. It becomes difficult to flow the refrigerant gas to the outlet side even by convection of the refrigerant gas.

If the heat exchanger structure forming the demister is a mesh fin heat exchanger structure 5 in which a plurality of mesh fins 5b, 5b ... Are laminated on both sides of the heat transfer tube 5a, for example. Mesh fins 5b, 5b ...
Due to the high heat exchange performance due to, the oil mist component is particularly effectively cooled to increase the viscosity and the mesh itself of the mesh fins 5b, 5b ... Performs a demister function, so that the structure is simplified.

If the demister having the above heat exchanger structure is incorporated in the refrigerating circuit of the refrigerating apparatus so that the low temperature refrigerant from the evaporator 14 to the compressor 11 is used as the heat exchanging refrigerant, A separate heat exchange refrigerant is not required, and the configuration is simple.

Then, in that case, the refrigeration circuit is incorporated into the refrigeration system by using the main refrigerant pipe 23 from the evaporator 14 to the compressor 11 or in parallel with the main refrigerant pipe 23. This is done using the installed bypass refrigerant pipe 24. Therefore, it is easy to connect and install the heat transfer tube 5a. Further, if the flow rate adjusting means 8 that is incorporated by using the bypass refrigerant pipe 24 and adjusts the inflow amount of the low-temperature refrigerant is provided in the middle of the bypass refrigerant pipe 24, depending on the size of the refrigeration load. In addition to being able to operate, the heat exchange capacity according to the amount of oil mist component in the refrigerant gas, in other words, the viscosity of the oil mist component can be adjusted, and the separation efficiency of the oil mist component can be controlled with high accuracy. become.

[0017]

As a result of the above, according to the oil mist separator of the present invention, the oil separation efficiency is improved, so that the pressure loss in the refrigerant pipe is reduced and the heat transfer performance of the heat exchanger is improved.

Since almost no oil is mixed in the refrigeration cycle, the amount of filled oil can be reduced and the reliability can be improved.

Even if the oil does not dissolve in the refrigerant or it hardly dissolves in the refrigerant, it is possible to reliably return sufficient oil to the compressor side.

[0020]

【Example】

(Embodiment 1) FIGS. 1 to 3 show the structure of an oil mist separator according to Embodiment 1 of the present invention.

First, FIG. 1 shows the oil mist separator 1
The reference numeral 1 indicates a tank-like casing. An inlet pipe 2 and an outlet pipe 3 for the refrigerant gas are inserted and fixed in the upper part of the casing 1 from above to below, while a drain pipe 4 is inserted and fixed in the lower part from below to above.

A mesh fin heat exchanger 5 forming a demister is supported at an intermediate position inside the casing 1 by a shield plate 6 around the mesh fin heat exchanger 5 so that the mesh fin heat exchanger 5 is inclined as shown in FIG. Has been done. And
The inlet pipe 2 is opened corresponding to the upper portion of the mesh fin heat exchanger 5 which is inclined.

The mesh fin heat exchanger 5 comprises a plurality of mesh fins 5b, 5b ...
Are superposed and laminated while maintaining a predetermined fin pitch, and have extremely high heat transfer performance as a characteristic of the mesh fin. And the mesh fins 5b, 5b
The diameter of the mesh of ... Is formed to the optimum size for separating the oil mist in the refrigerant gas.

Next, the oil mist separator 10 configured as described above is used in the compressor 1 as shown in FIG. 2, for example.
1, the condenser 12, the expansion valve 13, and the evaporator 14 are installed in a refrigerating circuit in the state shown in the drawing.

That is, the inlet pipe 2 is connected to the refrigerant gas outlet side of the compressor 11, and the outlet pipe 3 is connected to the refrigerant gas inlet port of the condenser 12 via refrigerant pipes 21 and 22, respectively. One end side of the heat transfer tube 5a of the mesh fin heat exchanger 5 is connected to the low temperature refrigerant outlet side of the evaporator 14 and the other end side thereof is connected to the low temperature refrigerant inlet side of the compressor 11 via a main refrigerant pipe 23, respectively. ing.

Further, the drain pipe 7 is the compressor 1
It is connected to the first oil return port via an oil return pipe 25.

Therefore, according to this structure, the demister section of the oil mist separator 10 is constituted by the mesh fin heat exchanger 5 capable of cooling and exchanging heat with the low temperature refrigerant from the evaporator 14, and through the inlet pipe 2. The demister, that is, the compressor 1 supplied from above to the mesh fins 5b, 5b ... of the mesh fin heat exchanger 5.
The oil mist component in the high-temperature refrigerant gas containing the oil mist component from 1 is appropriately cooled to be in a high viscosity state, and formed into a thin film on the inner wall portion of the shielding plate 6 and the oil mist separator casing 1 as in the conventional case. It will not adhere and rise to the vicinity of the outlet pipe 3 by convection (Fig. 3
reference). As a result, the amount of oil mist supplied to the condenser 12 side through the outlet pipe 3 is greatly reduced, the separation efficiency is greatly improved, and the oil is reliably returned to the compressor 11 side.

In the mesh fin 5b of the mesh fin heat exchanger 5 as described above, oil droplets staying on the mesh are less likely to be scattered, and supersaturated oil droplets flow down relatively smoothly. It was confirmed as a result of the experiment.

Generally, an oil film has a large correlation function between viscosity and temperature, and has a characteristic of rapidly increasing viscosity as the temperature decreases.
FIG. 6 is a temperature-viscosity diagram of SUNISO-4GS generally used for refrigerants such as Freon R22. According to this, when the refrigerant temperature changes from 90 ° C. to 80 ° C., the viscosity becomes about 35 ° C. You can see that it increases by%.

As shown in FIG. 7, the oil having a low viscosity forms a thin liquid film on the inner wall surface of the casing, wraps around to the mouth of the outlet pipe, and flows into the refrigeration cycle by being accompanied by the refrigerant gas. Therefore, with the oil mist separator, it was not possible to completely separate the oil in the case of low-viscosity oil, irrespective of its structure.

However, when the low temperature cooling function is added to the demister section to greatly increase the viscosity of the oil passing therethrough as in the embodiment of the present invention, the oil film on the inner wall surface of the casing becomes very thin, or It becomes impossible to form the oil film itself, and evaporation of the oil is also suppressed, so that it is possible to obtain an oil separation efficiency higher than that in the past.

(Embodiment 2) Next, FIG. 4 shows the structure of an oil mist separator according to Embodiment 2 of the present invention.

In the configuration of this embodiment, the refrigerant pipe for the heat transfer pipe 5a of the mesh fin heat exchanger 5 constituting the demister section is connected to the main refrigerant pipe 23 between the evaporator 14 and the compressor 11 as in the first embodiment. A bypass refrigerant piping structure 24 different from the main refrigerant piping 23 from the evaporator 14 to the compressor 11 is formed instead of using the same, and a flow rate adjusting valve 8 is provided in the middle thereof. It is a thing.

If the cooling temperature of the mesh fin heat exchanger 5 placed in the oil mist separator 10 is too low, the temperature of the gas discharged from the compressor 11 will be too low, and the capacity of the condenser 12 will be low. Is concerned.
Therefore, the mesh fin heat exchanger 5 must be operated in a temperature range in which the oil viscosity and the vapor pressure, which are initially aimed at, are reduced without reducing the capacity of the condenser 12. That is, the temperature of the refrigerant gas discharged from the compressor 11 is now T ₁ , and the temperature of the gas outlet side refrigerant of the oil mist separator 10 is T _2.
Then, it is necessary to operate the heat exchanger 5 in the range of ΔT = T ₁ −T ₂ within the range of Ta ≦ ΔT ≦ Tb.

When ΔT ≦ Ta, it means that the refrigerant gas is not sufficiently cooled in the oil mist separator 10, so that the oil viscosity does not become sufficiently large and the oil separation efficiency decreases. Can be considered. Therefore, the opening degree of the flow rate adjusting valve 8 is increased to increase the low temperature refrigerant flow rate from the evaporator 14 flowing through the bypass refrigerant pipe 24 to increase the cooling capacity of the mesh fin heat exchanger 5 placed in the oil mist separator 10. Then, the temperature is adjusted so that Ta ≦ ΔT.

On the other hand, when Tb≤ΔT, the opposite is true, which indicates that the refrigerant gas temperature is too low, and the opening of the flow rate adjusting valve 8 is narrowed to prevent the refrigerant from the evaporator 14 flowing through the bypass refrigerant pipe 24. By decreasing the low temperature refrigerant flow rate and increasing the refrigerant gas temperature, it is possible to obtain an appropriate outlet side refrigerant gas temperature of the oil mist separator 10. As a result, the condenser 12 can maintain a stable capacity.

(Embodiment 3) FIG. 5 shows the construction of an oil mist separator for a refrigerating machine according to Embodiment 3 of the present invention.

In the construction of the embodiment, for example, a demister comprising a mesh fin heat exchanger having a vertically long sleeve structure below the inlet pipe 2 and the outlet pipe 3 introduced into a cylindrical oil mist separator casing 1, respectively. It is characterized in that 16 and 17 are attached, and a partition plate 19 partitions the space between them.

Each of the demisters 16 and 17 is incorporated in the bypass refrigerant pipe 24 similar to that of the second embodiment at the portions of the supporting members 2a and 3a in the lid portion 1A. Therefore, the low temperature refrigerant from the evaporator 14 similar to that shown in FIG. 4 flows through the bypass refrigerant pipe 24 to the heat transfer pipe (not shown) between the cylindrical mesh fins, and is introduced from the inlet pipe 2 by this. The oil mist component in the high-temperature refrigerant gas is rapidly cooled to increase its viscosity, and is made into droplets and dropped without causing diffusion and convection in the oil mist separator casing 1 as much as possible, and one outlet pipe The residual mist component sucked into the 3 side is also more effectively cooled and is reliably separated by the demister 17 part. As a result, the efficiency of separating oil mist components is greatly improved.

When the amount of the oil separated as described above and staying at the bottom of the oil mist separator casing 1 becomes a certain amount or more, the float 15 is actuated and the valve is operated via the lever 15. 4a is opened, and the same oil is returned to the compressor side through the oil return pipe 4.

Reference numeral 18 is a float base provided on the bottom portion 1B of the oil mist separator casing 1.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of an oil mist separator according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration in a state where the oil mist separator is incorporated in a refrigeration circuit.

FIG. 3 is an enlarged cross-sectional view of a main part showing an operation of the oil mist separator.

FIG. 4 is a diagram showing a configuration of an oil mist separator according to a second embodiment of the present invention.

FIG. 5 is a sectional view showing a configuration of an oil mist separator according to a third embodiment of the present invention.

FIG. 6 is a temperature-viscosity characteristic diagram of a compressor oil generally used for a CFC-based refrigerant.

FIG. 7 is a diagram showing a configuration and problems of a conventional oil mist separator.

[Explanation of symbols]

1 is an oil mist separator casing, 2 is an inlet pipe,
3 is an outlet pipe, 5 is a mesh fin heat exchanger, 5a is a heat transfer pipe, 5b is a mesh fin, 6 is a shield plate, 8 is a flow regulating valve, 10 is an oil mist separator, 11 is a compressor, 1
2 is a condenser and 14 is an evaporator.

Claims (6)

[Claims] 1. A demister having a mesh structure for separating oil mist components is provided in an oil mist separator casing (1) to which high temperature refrigerant gas containing oil mist from a compressor (11) is supplied, and the demister is provided. An oil mist separator for refrigeration equipment formed into a heat exchanger structure. 2. The oil mist separator for a refrigerating apparatus according to claim 1, wherein the demister having a heat exchanger structure is constituted by a mesh fin heat exchanger (5). 3. A demister having a heat exchanger structure is incorporated in the refrigerating circuit of the refrigerating apparatus so that a low temperature refrigerant from the evaporator (14) to the compressor (11) is used as a heat exchanging refrigerant. The oil mist separator for a refrigerating apparatus according to claim 1 or 2, which is configured. 4. A demister having a heat exchanger structure is incorporated in a refrigeration circuit by connecting the evaporator (14) of the refrigeration system to a compressor.
The oil mist separator for a refrigerating apparatus according to claim 3, wherein the main refrigerant pipe to (11) is used. 5. The demister having a heat exchanger structure is installed in a refrigeration circuit by connecting the evaporator (14) of the refrigeration system to a compressor.
The oil mist separator for a refrigerating machine according to claim 3, wherein a bypass refrigerant pipe provided in parallel with the main refrigerant pipe to (11) is used. 6. The oil mist separator for a refrigerating apparatus according to claim 5, wherein a flow rate adjusting means (8) for adjusting the inflow amount of the low temperature refrigerant is provided in the middle of the bypass refrigerant pipe.