JPH11325668A - Dryer for air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent welding loss of a resin filter by ensuring a sufficient interval between a filter and the welded part at the inlet/outlet thereof. SOLUTION: The dryer comprises retaining planes 2 (punching metal, metal mesh, or the like) arranged closely to the opposite ends in a dryer container 1 and filled with drying agent 5 through a resin filter 4. The drying agent 5 is supported stably in specified mode by urging one retaining plane 2 with a spring 3. A pipe is welded through a brazing filter metal of phosphor copper, for example, in order to connect the dryer with a cycle at a welded part 6. In order to prevent welding loss of the filter 4, the filter 4 is spaced apart by 50-60 mm from the welded part 6. Consequently, the effect of thermal conduction is suppressed and the reliability is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a heat pump refrigeration cycle in which a desiccant needs to be added during the cycle for moisture management. In particular, in the field of air conditioning, H22 is an alternative refrigerant to R22.
It is applied to the case where water management after operation start is necessary when using a FC-based refrigerant and using a highly hydrolyzable oil such as a polyol ester as a refrigerating machine oil.

[0002]

2. Description of the Related Art Conventionally, the refrigerant of a home room air conditioner is R
22, the refrigerating machine oil uses mineral oil, which is a system that is relatively resistant to moisture, and at present, there is almost no need to add a desiccant for removing moisture during the cycle. However, from the viewpoint of protecting the global environment, the air-conditioning refrigerant is a conventional HCF.
There is a shift from C-based R22 to HFC-based.
Since the refrigerating machine oil does not sufficiently dissolve in the HFC-based refrigerant because the molecular polarization state is different from that of the HCFC-based refrigerant, conventional mineral oil cannot be used as the refrigerating machine oil. Therefore, an artificial synthetic oil such as a polyol ester is used as a refrigerator oil having a required solubility.

[0003] However, in particular, polyol ester-based refrigerating machine oils are highly hydrolyzable, and when there is moisture during a cycle, they react with the moisture and are decomposed into fatty acids and alcohols.
This decomposition product directly soaks the sliding part and further reacts to form a precipitate, which adheres in the cycle and causes clogging of the cycle.

On the other hand, the mainstream of air conditioners, especially home room air conditioners, is to separate an indoor unit and an outdoor unit, install them inside and outside the room, and connect them using copper pipes for connection at the site during construction. In general, the cycle is completed. In comparison with a product (for example, a refrigerator) that completes a cycle in a factory and then is shipped, there is a great possibility that moisture enters the cycle, including the moisture in the connection piping. Therefore, water management (removal) after the cycle operation is essential.

However, when a desiccant is introduced into the main stream of the cycle, the body of the desiccant is rubbed, particularly when a gas refrigerant having a high flow rate of the refrigerant passes through the desiccant, generating abrasion powder, which causes clogging and abnormalities in the cycle. It causes wear. In the heat pump cycle, the flow direction of the refrigerant and the state of the gas phase / liquid phase are reversed depending on each operation state of cooling and heating. For this reason, even if the desiccant is installed so as not to cause abrasion in a cooling state, abrasion occurs in a heating state.

As a method for preventing abrasion, Japanese Unexamined Patent Publication No.
As disclosed in Japanese Patent Application Laid-Open No. 54-24348, a method is considered in which a dryer is attached and then removed in an operation mode in which a liquid refrigerant flows. However, it is difficult for a small home-use air conditioner to be reworked once installed.

[0007] In view of the above, if abrasion powder is generated, it is considered that the abrasion powder is confined inside the dryer, and a filter is provided at the entrance of the dryer.
No. 593 and the like.

[0008]

However, as a conventional filter inserted into a dryer, a metal filter or glass wool is mainly used. In either case, the filter is made thicker in order to catch fine abrasion powder. Therefore, the method becomes large and expensive. In addition, when the dryer is directly inserted into the refrigeration cycle, if the filter is clogged with the abrasion powder, the cycle is directly clogged, and there is a possibility that the performance may be reduced or the operation may not be possible.

[0009]

In order to solve the above problem, a filter made of resin is used as a filter material, and a thin, inexpensive, and fine-grained filter is used.
However, resin has a low heat-resistant temperature, and when heat during welding is transmitted to the filter through the main body, the filter is melted by the heat. Therefore, by cooling the dryer body at the time of welding and providing a sufficient distance between the welded portion and the filter, it is possible to suppress a rise in the temperature of the filter due to the propagation of heat from the welded portion and to use a resin filter.

In order to prevent the abrasion powder from flowing out, the finer the filter, the better the filter. However, the finer the filter, the more easily the filter is clogged. Therefore, by providing a detour other than the main flow of the refrigeration cycle, and installing a dryer here, even if the dryer is clogged, the operation of the refrigeration cycle is not affected. Further, by providing a flow control device such as a capillary in the bypass, the flow velocity of the refrigerant flowing through the dryer can be limited, and the generation of abrasion powder can be suppressed, thereby suppressing the occurrence of filter clogging.

[0011]

Embodiments of the present invention will be described below.

FIG. 1 is a configuration diagram of a dryer showing a basic configuration of the present invention. In the figure, 1 is a dryer container, 2 is a holding plate (such as punched metal or wire mesh), 3 is a spring, 4 is a filter, 5 is a desiccant, and 6 is a welded portion for connection to a cycle.

In the case where a dryer is connected to the cycle, the pipe of the cycle is welded to the portion 6 with a phosphor copper braze or the like. Therefore, the temperature of the welded part is 700-800 ° C.
This is transmitted to the filter portion by heat conduction. When the distance from the tip of the welding portion to the filter portion is 30 to 40 mm, the temperature of the filter portion is 200 ° C. or higher without cooling, and a cloth wetted with water, which is a general cooling method, is wound (hereinafter referred to as winding cooling). Even when the cooling is performed, the temperature is about 100 ° C., which is almost the same as or higher than the thermal deformation temperature of the resin. Therefore, the filter is deformed due to heat, and the filter is melted and the filter does not operate.

Therefore, the distance from the welded portion to the filter is set to 50 to 60 mm, and the effect of heat conduction is reduced by separating the welded portion from the filter.
It was possible to reduce the temperature of the filter portion during winding cooling to about 80 to 90. Further, in taking a distance, the thinner portion of the welding portion 6 is made longer than the large-diameter portion of the main body, thereby facilitating the application of the welding flame to the welding portion, thereby improving the workability of welding and reducing the welding time. By reducing the length, the amount of heat transmitted to the filter portion can be further reduced.

FIG. 2 is a cycle configuration diagram showing the configuration of the present invention. In the figure, 7 is a compressor, 8 is a four-way valve, 9 is an outdoor heat exchanger, 10 is a throttle device (expansion valve etc.), 11 is an indoor heat exchanger, 12 is a dryer, and 13 is a flow control device (capillary etc.). Show. However, in the following description, the flow control device 13 is considered as a capillary.

During the cooling operation, the discharged gas from the compressor 7 passes through the four-way valve 8 and enters the outdoor heat exchanger 9, where it is condensed and liquefied. A part of the liquefied refrigerant passes through the expansion device 10, expands, enters the indoor heat exchanger 11, evaporates, and returns to the compressor 7. At this time, a part of the liquid refrigerant that has exited from the outdoor heat exchanger 9 flows to the dryer 12 side. The refrigerant having passed through the dryer 12 passes through the capillary 13. It is the liquid refrigerant that passes through the dryer, the flow velocity is relatively slow, and the flow rate of the refrigerant is adjusted by setting the value of the capillary to an appropriate value to reduce the amount of the refrigerant flowing to the dryer side. At the same time, the effect on the operation of the cycle can be reduced.

For example, when R410A is used as the refrigerant, the refrigerant circulation rate is 60 kg / h, the condensing pressure is 3000 kPa, and the heat exchanger outlet temperature is 30 ° C., the liquid density of the refrigerant is about 1036 kg.
/ M ³ . The flow velocity of the refrigerant in the copper pipe with an inner diameter of 4.95 mm is about 0.838 m / s, while the flow velocity when flowing this directly into a dryer in which 25 g of a desiccant is sealed in a copper pipe with an outer diameter of 25 mm is about 3.83 m / S, and the flow rate is tripled. Therefore, when the refrigerant is directly passed through the dryer, the possibility of generating crushed powder increases, and when the filter is clogged with the generated crushed powder, cycle clogging occurs.

Therefore, a branch circuit is provided as shown in FIG. 2 and a dryer is provided on the branch circuit side. Thus, even if the filter is clogged, the flow of the main cycle of the refrigeration cycle is not hindered, and no cycle clogging occurs. Also, by using a capillary 13 that is sufficiently thin for the main stream portion, the amount of refrigerant flowing to the dryer 12 side is limited,
The influence of the branch portion on the refrigeration cycle can be suppressed.

In the heating operation, for example, R
Assuming 410 A, evaporating pressure of 780 kPa, and dryness of 25% immediately after the expansion valve, the density of the refrigerant is about 912 kg / m ^3, which is 88% at the time of cooling. It is about 1.13 times that of cooling. In general, the amount of circulating refrigerant is larger during heating than during cooling, so the refrigerant flow rate further increases. Therefore, passing the refrigerant directly through the dryer 12 may cause the desiccant to be damaged by the flow of the refrigerant more than during cooling. Therefore, it is effective to install the filter in a branch circuit as in the case of the cooling operation and restrict the flow rate to prevent the desiccant from being pulverized and to prevent a cycle operation failure due to filter clogging.

In the configuration shown in FIG. 2, a branch circuit is provided between the outdoor heat exchanger and the expansion valve so that the liquid refrigerant flows during cooling. The position of the branch circuit is opposite to the outdoor heat exchanger. A similar effect can be obtained by installing and heating the liquid refrigerant during heating.

[0021]

According to the present invention, in a refrigeration cycle using a dryer, a filter is used inside the dryer to capture pulverized powder generated from a desiccant.
A thin and inexpensive filter made of resin can be used. In addition, by installing a dryer in the branch circuit with an appropriate shunt resistor, the effect of the branch circuit on the refrigeration cycle performance is minimized, and even if the dryer is clogged, the refrigeration cycle becomes blocked and operation becomes impossible. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a dryer targeted by the present invention.

FIG. 2 is a circuit diagram showing a refrigeration cycle to which the present invention is applied.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Dryer container (main body), 2 ... Holding plate (punching metal), 3 ... Spring, 4 ... Filter, 5 ... Drying agent, 6 ... Welded part, 7 ... Compressor, 8 ... Four-way valve, 9 ... Outdoor heat exchange vessel,
Reference numeral 10: throttle device, 11: indoor heat exchanger, 12: dryer, 13: flow control device.

Claims (1)

[Claims] 1. A heat pump type refrigeration cycle comprising a compressor, a four-way valve, an outdoor heat exchanger, an expansion device, and an indoor heat exchanger connected in order. An air conditioner dryer in which a desiccant is sealed and a thin filter made of resin is installed at both ends of an entrance and exit, wherein a sufficient space is provided between a welded portion at both ends and the filter.