JPH0771842A - Cooling device - Google Patents

Abstract

PURPOSE:To obtain a cooling device provided with a foreign matter removal means which is capable of removing a foreign matter to a satisfactory extent and being free of a source of refrigerant contamination for its self by installing a cooling device which circulates refrigerants by way of a filter device which provides a particulate filler and a filmy filter. CONSTITUTION:A filter device 1 is designed to install a metal filter 11, which sinters various kinds of fillers, such as a molecular sieve 5, activated coal 7, silica gel 9 and tungsten particles, in a copper-made large-sized pipe, for example. A teflon filter 13 is installed to the outlet of the fillers while a metal net 15 is installed between these fillers as well, thereby filtering a foreign matter from refrigerants flowing out from a compressor and discharging cleaned refrigerants 30. This construction makes it possible to remove foreign matters from the refrigerants 20 with high efficiency and adopt other refrigerants which do not include Freon or fluorocarbons for a cooling cycle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device such as a refrigerator or a freezer having a cooling cycle for circulating a refrigerant.

[0002]

2. Description of the Related Art Conventionally, Freon CFC-12 is used as a refrigerant for a cooling cycle of a cooling device such as a refrigerator, a freezer and a cooler.
CFC-115, R-502 (HCFC-22 / CFC
(-115 mixed refrigerant) and the like were used. Such a CFC agent is a highly stable and excellent refrigerant. However, since the influence of CFCs on the ozone layer has become a problem in recent years, the restrictions on the use of CFCs have been tightened, and the refrigerants used in the cooling devices are also used as alternative CFC agents and refrigerants such as HCFC-22 and HFC-134a. Forced to change to other possible substances.

When a CFC substitute or other refrigerant is applied to a cooling device in accordance with the regulations for the use of CFCs, it is necessary to replace the lubricating oil used in the compressor of the cooling device with one that is compatible with the refrigerant. Further, those used as a cleaning agent in the manufacturing and assembling process of the cooling device such as CFC-113 must be replaced with a CFC substitute or the like, or must be changed to another cleaning method.

When such changes are made, various foreign substances and impurities are mixed or generated in the refrigerant.

If the cooling device is continuously operated without removing such foreign matters and contaminants from the refrigerant, these foreign matters impede the circulation of the refrigerant. In particular, the cooling cycle has a narrow flow path called a capillary tube, and it is easy for clogging to occur at such a portion. Therefore, due to insufficient circulation or stoppage of circulation of the refrigerant, a failure of the cooling device is caused in a short period of time, and the service life of the device is shortened. Therefore, only products with very low commercial value can be obtained. Therefore, Freon CFC-
In order to put into practical use a cooling device that does not use 12 or the like, it is necessary to solve the problem of circulation inhibition due to foreign matter.

At present, as a technique for removing foreign matters contained in a refrigerant, a column in which a molecular sieve, which is generally used as a dehumidifying agent, is packed in a cooling cycle has been proposed.

[0007]

However, the molecular sieve is easily crushed, and fine powder is easily generated by the vibration of the compressor, which is likely to cause refrigerant contamination. For this reason, active adoption of the above proposal has not been seen. or,
Since Freon CFC-12 and the like are extremely excellent refrigerants, the above-mentioned problems rarely occur, so that attention to foreign matter removal has been rare in the past.
Other than the above, no other proposal has been made.

The present invention has been made in order to solve such a problem, and provides a cooling device having a foreign matter removing means which is excellent in foreign matter removing ability and which does not itself become a source of refrigerant pollution. The purpose is.

[0009]

[Means for Solving the Problems] In order to achieve the above object, the present inventors have conducted extensive studies and found that a foreign substance can be efficiently removed by combining a particulate filler and a membrane filter. Invented the cooling device of the present invention.

The cooling device of the present invention is characterized by comprising a cooling cycle in which a refrigerant is circulated through a filtering device having a particulate filler and a membrane filter.

[0011]

When the refrigerant passes through the removing device including the particulate filler and the membrane filter, the particulate filler traps relatively large particles of foreign matter, and the foreign matter in the refrigerant depends on its type. Are adsorbed on the surface of the filler and in the pores. The smaller foreign particles that are not captured by the filler are removed from the refrigerant by the membrane filter. The foreign particles are captured by being dispersed by the particulate filler and the membrane filter, and the obstruction of the particle trapping force and adsorption force of the filler can be prevented.

The present invention will be described in more detail below.

When the refrigerant, the lubricating oil, and the cleaning agent are changed in order to comply with the regulations for the use of CFCs, the changes that occur are as follows.

First, the conventionally used Freon CFC-
Since 12 and the like are substances that are extremely stable and have high solubility, by changing the refrigerant to an alternative agent, waste products are easily generated due to decomposition of the circulating refrigerant or reaction with the lubricating oil. And, due to the low solubility of the substitute agent, these waste substances are likely to precipitate from the refrigerant, and the fluorocarbon CFC
When -12 or the like is used, a foreign substance that does not cause a problem is deposited.

Furthermore, by changing the lubricating oil of the compressor, the lubricating performance and the stability of the lubricating oil may change, and the amount of decomposed products of the lubricating oil and the amount of abrasion powder on the sliding parts of the compressor may increase. Freon CFC-12, which has a lower solubility than freon, cannot be circulated while incorporating these impurities, and the impurities are deposited in the form of tar and adhere to the circulation path or cause clogging.

By changing the cleaning agent used in the manufacturing and assembling process of the cooling device, a high detergency cannot be obtained, and the processing oil and water used in the manufacturing and assembling process easily remain. Further, if the cleaning method without using the cleaning agent, for example, switching to the work using paper or cloth is used, the possibility that the used fine fibers such as paper or cloth are mixed increases.

Therefore, the refrigerant in the cooling cycle contains various foreign substances such as large foreign substances such as fiber dust, fine powder such as abrasion powder, tar-like oily substances and mixed water. , A filter device capable of removing all of these over a long period of time is incorporated into the cooling cycle. The filtration device incorporated in the present invention is a combination of a particulate filler and a membrane filter.

Generally, the particulate filler constitutes a filtering means having a gap in a state of being packed in a column or the like, and the size of the gap is controlled to some extent by adjusting the particle size of the filler particles. be able to. However, it is quite difficult to form extremely small gaps accurately even with a fine packing, and if such a packing is not securely held in the column, it becomes a contaminating source of the refrigerant.

On the other hand, the membrane filter has been remarkably developed in recent years, and various filters having high functions and special functions have been supplied. In particular, an excellent membrane filter for fine particles has been developed, and it is possible to reliably remove fine foreign substances that block the capillary flow path of the cooling cycle. However, the membrane filter is not suitable for filtering a large amount of particles, and has a drawback that the filtration area must be extremely large in order to handle a large amount of particles. Therefore, a membranous filter that makes it possible to continue to filter the refrigerant for a long time is very expensive and
It must be structurally not simple.

As described above, the foreign matter that causes a circulation failure when the refrigerant is changed to one other than Freon CFC-12, etc.
Includes particles of various sizes, eg 0.5-1 μ
Some of them are as small as m and some are as large as 1 mm.
In addition, since it is a wide variety of materials including fiber fragments and tar-like organic deposits, it is desirable that the refrigerant can be widely applied to objects in order to remove foreign substances from the refrigerant. In addition, the removal capacity must be large to enable long-term use. As a result of considering such a fact, the present inventors have succeeded in constructing a filtration device having a wide range of applicability and a high capacity at low cost by combining a particulate filler and a membrane filter.

In the present invention, as the particulate filler, various adsorbents and porous agents can be mentioned.
For example, as the adsorbent, molecular sieve or silica gel that is usually used as a desiccant, activated carbon or acid clay, activated clay that is used as a decolorizing deodorant, etc. as a porous agent, bentonite, various porous ceramics such as diatomaceous earth. Can be mentioned. These can be prepared in various particle sizes as needed, but generally, those that are inexpensively available have a particle size of about 500 μm to 5 mm. The gap between the agents is 80 μm
It will be about 0.8 mm.

On the other hand, as the membrane filter, for example,
Polytetrafluoroethylene (hereinafter referred to as PTFE),
Examples thereof include polymer filters such as polyethylene and polypropylene. Particularly, the PTFE filter is excellent in heat resistance and mechanical strength and has high stability, and thus is particularly preferable as a filter applied to the present invention. Average PTF
The E filter has pores of about 0.2 to 0.5 μm, and can reliably remove the smallest class of foreign particles mixed in the refrigerant. Further, even if the filler particles are crushed by vibration or the like to generate fine powder, it is possible to sufficiently cope with the problem.

Therefore, in the filtering device of the cooling device according to the present invention, the particulate filler plays a role of capturing a large amount of a relatively large foreign substance, and the membrane filter captures a minute foreign substance. That is, since the classification and capture are performed, the defects of both materials are compensated, and the capture capacity of foreign matter is secured and the capture level is improved.

In the above structure, the particulate fillers having different particle diameters are added in the longitudinal direction of the filtering device (direction in which the refrigerant flows).
By arranging the particles so that the particle diameter gradually decreases, it is possible to further disperse and capture the foreign matter.
That is, the filtration is performed three-dimensionally instead of two-dimensionally. By arranging the fillers according to the particle diameters in this way, the gaps between the fillers become gradually smaller as they advance along the flow direction of the refrigerant, and the classification and trapping of foreign matter is performed in smaller pieces. The packing configuration that enables the classification capture increases not only the physical filtration efficiency of the packing material but also the adsorption efficiency of the adsorbent that adsorbs the specific substance. That is, it is possible to reduce the inhibition of adsorption of the filler having a specific adsorption capacity by the particles to be captured, so that the adsorption force is easily exerted. Therefore, it is preferable that the arrangement of the fillers be devised in consideration of the inherent performance of each filler and the composition of the foreign matter in the refrigerant.

The above-mentioned filler is filled in a tube equipped with a membrane filter. The pipe is made of a material, such as a copper pipe, which is easy to process and weld, and which is not deformed by the pressure applied in the cooling cycle, and which itself does not generate a foreign substance that hinders the normal circulation of the refrigerant. Created. The membranous filter is fixed to the tube so as not to move by hydraulic pressure, and is filled with the filler according to the above configuration. The upstream end of the filler is preferably retained, such as by a copper net, to prevent the filler from moving within the tube during assembly of the filter. Further, a net may be used to partition between the various fillers. Such a mesh serves to prevent the fillers from being mixed with each other and to disperse the load by the flow pressure of the refrigerant so that the load is not applied only to the filter.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a filtration device 1 incorporated in the cooling device of the present invention. The filtration device 1 has a copper tube 3,
It is composed of upstream and downstream wax-like inlets and outlets, and a central large-diameter portion. Filler 5 in the large diameter part of pipe 3,
7, 9, 11 are filled. The filler 5 is a molecular sieve having a particle size of 5 mm, 7 is activated carbon having a particle size of 3 mm, 9 is silica gel having a particle size of 1 mm, and 11 is a metal filter having a pore size of 800 μm obtained by sintering tungsten powder. On the outlet side of the filler, pores having a pore diameter of 0.5 μm (porosity 70 to 70
Teflon filter 13 having 80%),
It is fixed to the pipe 3. Copper wire mesh 15 is arranged at the boundary and end of each filler and filter.

From the refrigerant 20 flowing from the compressor, fiber debris, relatively large abrasion powder and water are removed by the molecular sieve of the filtration device 1. Next, activated carbon adsorbs and removes organic impurities, and silica gel removes water and organic impurities, especially basic impurities. At the same time, the solid particles having a particle diameter of about 1500 μm are also removed. While passing through the metal filter, particle size 800 ~ 15
Fine particles of about 00 μm are removed, and finally, ultrafine particles having a particle size of 0.5 μm or more are removed by the Teflon filter 13. Therefore, the refrigerant 30 that has passed through the filtration device 1
Becomes almost free of foreign matter, and thereafter, the cooling cycle is circulated.

[0029]

As described above, the cooling device of the present invention is provided with the filtering device capable of efficiently removing impurities from the refrigerant, and enables the use of a refrigerant other than CFCs in the cooling cycle. Therefore, its industrial value is extremely large. In addition, the cooling device of the present invention can prevent the circulation of the refrigerant from being obstructed for a long period of time by the filtering device, and thus can be a product with a long life.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a filtering device of a cooling device of the present invention.

[Explanation of symbols]

 1 Filtration device 5 Molecular sieve 7 Activated carbon 9 Silica gel 11 Metal filter 13 Teflon filter

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kimito Sakai 1 Komukai Toshiba-cho, Kouki-ku, Kawasaki-shi, Kanagawa Toshiba Research & Development Center

Claims (1)

[Claims] 1. A cooling device comprising a cooling cycle in which a refrigerant is circulated through a filtering device comprising a particulate filler and a membrane filter.