An in-line return air duct assembly

Abstract

The application relates to the technical field of refrigeration equipment pipeline accessories, in particular to an embedded return gas pipe assembly applied to a refrigerator and a freezer refrigeration system and used for connecting an evaporator outlet and a compressor suction end, which comprises a round tubular return gas pipe and a capillary tube, at least one groove is formed in the inner side of the pipe wall of the return gas pipe in the axial direction, the capillary tube is embedded in the groove, the outer surface of the pipe body of the embedded return gas pipe assembly is provided with an anticorrosive layer; the pipe opening of the return gas pipe is provided with a connecting pipe, the capillary tube is sealed and connected with the connecting pipe at the pipe opening of the return gas pipe through brazing or a lock ring to form a sealed connection part. The application can realize the following beneficial effects: 1. heat exchange efficiency is obviously improved, and the consumption of raw materials is reduced; 2. the capillary tube positioning is reliable, and there is no separation deviation in the processing process; 3. copper-aluminum electrochemical corrosion is inhibited, and the service life of the pipeline is prolonged; 4. the pipeline assembly has high universality, and the sealing forming mode can be selected, and many other beneficial effects are achieved.

Description

Technical Field

[0001] This invention relates to the field of refrigeration equipment piping accessories, specifically to an embedded return pipe assembly used in refrigerator and freezer refrigeration systems to connect the evaporator outlet and the compressor suction end. Background Technology

[0002] In household refrigerators and freezers, the return pipe is a core low-pressure pipeline connecting the evaporator outlet and the compressor suction end. The complete refrigeration cycle is as follows: the compressor discharges high-temperature, high-pressure gaseous refrigerant, which is then transported to the condenser for heat dissipation and converted into low-temperature, high-pressure liquid refrigerant; after being filtered to remove impurities, the liquid refrigerant is throttled and depressurized through a capillary tube to form a low-temperature, low-pressure liquid, which enters the evaporator to absorb heat and evaporate into a low-temperature, low-pressure gas; the low-temperature, low-pressure gaseous refrigerant then flows back to the compressor through the return pipe, completing the entire refrigeration cycle.

[0003] To improve the energy efficiency of refrigeration systems, the industry generally arranges the return pipe and capillary tube in parallel and closely together, relying on the temperature difference between the two to achieve heat exchange. This combined structure is called the return pipe assembly. The existing return pipe assembly is mainly constructed in the following ways: the return pipe and capillary tube are fixed by wrapping with aluminum foil tape, by binding with heat shrink tubing, or by soldering or laser welding.

[0004] Existing return gas pipes have many defects in production and use: 1. Only linear contact between the capillary tube and the return gas pipe is achieved, resulting in a small heat exchange contact area and poor heat exchange effect. If the overall energy efficiency standard is to be improved, the parallel length of the capillary tube and the return gas pipe can only be increased, which leads to a simultaneous increase in pipe material consumption and refrigerant charging, resulting in a significant increase in production costs.

[0005] 2. Poor pipe bonding stability, prone to performance failure. The structure of external binding with aluminum foil and heat shrink tubing makes it easy for the capillary tube to separate from the return pipe during the subsequent tube bending and forming process. This disrupts the heat exchange contact relationship and directly leads to a significant reduction in the refrigerator's cooling performance.

[0006] 3. Severe electrochemical corrosion of copper and aluminum leads to short product lifespan. Conventional return gas pipes are made of aluminum, while capillary tubes are made of copper. A potential difference exists between the two metals. Air, moisture, and electrolytes can easily seep into the gaps in the externally bundled pipe structure. Direct contact between the copper and aluminum metals causes an electrochemical reaction, resulting in rapid corrosion and perforation of the aluminum return gas pipe. To delay corrosion, the production process requires additional steps such as applying a base layer of aluminum foil and wrapping with multiple layers of aluminum foil. However, this only provides limited improvement in corrosion protection and increases material and labor costs.

[0007] 4. Automated production is difficult and product consistency is poor. The aluminum foil winding and heat shrink tubing installation processes are highly dependent on manual operation, making it difficult to achieve fully automated production line processing. This results in low production efficiency and high labor costs. The tightness of manual binding cannot be consistent, leading to significant differences in heat exchange and corrosion resistance between different batches of products, resulting in poor product quality stability. Summary of the Invention

[0008] To address the shortcomings of existing return gas pipe assemblies, such as low heat exchange efficiency, easy separation of capillary tubes from the return gas pipe, severe electrochemical corrosion of copper and aluminum, cumbersome processing procedures, and difficulty in automated mass production, this invention provides an embedded return gas pipe assembly. This assembly increases the heat exchange contact area between the capillary tube and the return gas pipe, achieving reliable capillary tube positioning and fixation. The capillary tube is housed inside the pipe body, isolating it from air and moisture, thus blocking the corrosion path caused by direct contact between copper and aluminum at the source. At the same time, it can improve the corrosion protection capability of the pipe sealing parts according to assembly requirements.

[0009] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: An embedded return air pipe assembly includes a cylindrical return air pipe and a capillary tube. The inner wall of the return air pipe has at least one groove along the axial direction, and the capillary tube is embedded in the groove.

[0010] As a preferred embodiment of the present invention, the cross-sectional shape of the groove is an arc, a U, or an Ω shape.

[0011] As a further improvement of the present invention, the outer surface of the embedded return air pipe assembly is provided with an anti-corrosion layer; the anti-corrosion layer may be an aluminum foil layer, a sprayed paint film layer, an impregnated paint film layer, a heat shrink tubing layer, a powder coating layer, or an electrophoretic layer.

[0012] As another preferred embodiment of the present invention, both ends of the capillary extend outside the opening of the return air pipe.

[0013] As a further assembly structure of the present invention, the inlet of the return gas pipe is equipped with a connecting pipe, and the capillary tube is sealed to the connecting pipe at the inlet of the return gas pipe by brazing or using a Lock ring to form a sealed connection part.

[0014] Furthermore, a protective component is provided on the outside of the sealing connection, which is a heat shrink tubing or a plastic sleeve.

[0015] Preferably, the return air pipe, capillary tube, and connecting pipe are all made of metal.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Heat exchange efficiency is significantly improved, reducing raw material consumption.

[0017] This invention embeds a capillary tube into an axial groove on the inner wall of the return gas pipe, forming a continuous surface contact for heat exchange with the outer wall of the capillary tube and the inner wall of the groove. The capillary tube directly contacts the refrigerant flowing inside the return gas pipe, resulting in a more direct heat exchange and conduction path. Under the premise of achieving the same refrigeration and heat exchange performance, the parallel laying length of the return gas pipe and the capillary tube can be shortened, reducing the amount of pipe materials and refrigerant required, and lowering the product manufacturing cost.

[0018] 2. Capillary positioning is reliable, and there is no separation or offset during processing.

[0019] The grooves on the inner wall of the return pipe provide radial and axial double restraint to the capillary tube. During post-processing steps such as bending and forming, the capillary tube remains contained and fitted inside the grooves, preventing displacement or detachment. This ensures stable heat exchange performance throughout the pipeline and avoids cooling performance degradation caused by pipeline separation.

[0020] 3. Inhibits electrochemical corrosion of copper and aluminum, extending the service life of pipelines.

[0021] The capillary tube is embedded in the groove inside the return gas pipe. The copper capillary tube and the aluminum return gas pipe are mutually restrained and fitted, reducing the gap for air and moisture intrusion and mitigating electrochemical reactions. Combined with the overall anti-corrosion layer on the outer surface of the pipe and the independent protective components of the sealing connection, a multi-layer anti-corrosion protection system is formed, which effectively delays pipeline corrosion and perforation and extends the service life of the product.

[0022] 4. The pipeline assembly is highly versatile, and the sealing molding method is optional.

[0023] The capillary tube extends out of the return gas pipe opening at both ends, leaving assembly allowance to facilitate connection with the system piping during the assembly of downstream refrigeration equipment; the matching connecting pipe at the pipe opening is an optional configuration as a transition joint, and two mature sealing solutions, brazing seal and Lock ring mechanical extrusion seal, are provided to adapt to the processing needs of different customer production lines; the sealing connection can be equipped with a separate protective component to isolate water vapor and oil stains and prevent leakage failure at the sealing position. Attached Figure Description

[0024] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a schematic diagram of the main structure of the present invention; Figure 3 This is a schematic diagram of the AA cross-section structure of the present invention; Figure 4 This is a schematic diagram of the structure of the present invention after the assembly of the connecting pipe and the Lock ring. The wavy line on the left is used to omit the pipe section extending to the left of the return pipe.

[0025] Reference numerals in the attached diagram: 1. Return air tube; 2. Capillary tube; 3. Connecting tube; 1-1 groove; 4. Locke ring. Detailed Implementation

[0026] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0027] like Figures 1-3 As shown, this is a basic structural embodiment of the present invention. The embedded return pipe assembly includes a cylindrical return pipe 1 and a capillary tube 2. At least one groove 1-1 is provided on the inner side of the pipe wall of the return pipe 1 along the axial direction, and the capillary tube 2 is embedded in the groove 1-1.

[0028] As a preferred structure of the present invention, the cross-sectional shape of the groove 1-1 is an arc shape, a U shape or an Ω shape.

[0029] As a further improvement of the present invention, the outer surface of the embedded return air pipe assembly is provided with an anti-corrosion layer; the anti-corrosion layer may be an aluminum foil layer, a sprayed paint film layer, an impregnated paint film layer, a heat shrink tubing layer, a powder coating layer, or an electrophoretic layer.

[0030] As another preferred structure of the present invention, the two ends of the capillary tube 2 extend out of the outside of the opening of the return gas pipe 1, so as to reserve assembly margin for the downstream refrigeration pipeline connection.

[0031] As attached Figure 4 As shown, this is an optional assembly implementation of the present invention: In the downstream assembly process of the complete machine pipeline, a connecting pipe 3 can be selectively assembled at the inlet of the return gas pipe 1 according to the pipeline docking requirements. The capillary tube 2 and the connecting pipe 3 at the inlet of the return gas pipe 1 can be sealed by brazing or by a Lock ring 4 to form a sealed connection part.

[0032] Furthermore, regardless of whether a brazed sealing structure or a Lock ring locking sealing structure is used, a protective component is installed on the outside of the sealing connection. This protective component can be made of heat shrink tubing or a plastic ferrule. The protective component can isolate air, moisture, and corrosive media from the environment, thereby improving the long-term stability and corrosion resistance of the sealing position.

[0033] It should be clarified that the connecting pipes, sealing molding methods, and protective components are all optional structures in the overall assembly process and can be flexibly selected or omitted depending on the actual piping assembly conditions. (Appendix) Figure 4 The wavy line on the left is a simplified drafting technique. Because the actual forming length of the return pipe is quite long, the view omits the pipe section extending to the left.

[0034] Preferably, the return air pipe 1, capillary tube 2, and connecting pipe 3 are all made of metal.

[0035] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. An embedded return air pipe assembly, comprising a cylindrical return air pipe and a capillary tube, characterized in that: The inner wall of the return pipe has at least one groove along the axial direction, and the capillary is embedded in the groove.

2. The embedded return air pipe assembly according to claim 1, characterized in that: The cross-sectional shape of the groove is arc-shaped, U-shaped, or Ω-shaped.

3. The embedded return air pipe assembly according to claim 1, characterized in that: The outer surface of the embedded return air pipe assembly is provided with an anti-corrosion layer.

4. The embedded return air pipe assembly according to claim 3, characterized in that: The anti-corrosion layer is an aluminum foil layer, a sprayed paint film layer, an impregnated paint film layer, a heat shrink tubing layer, a powder coating layer, or an electrophoretic layer.

5. The embedded return air pipe assembly according to claim 1, characterized in that: Both ends of the capillary extend outside the opening of the return air pipe.

6. The embedded return air pipe assembly according to claim 5, characterized in that: The return gas pipe is fitted with a connecting pipe at its opening. The capillary tube is connected to the connecting pipe at the opening of the return gas pipe by brazing or using a Lock ring to form a sealed connection.

7. The embedded return air pipe assembly according to claim 6, characterized in that: The outer side of the sealing connection is provided with a protective component, which is a heat shrink tubing or a plastic sleeve.

8. The embedded return air pipe assembly according to claim 6, characterized in that: The return air pipe, capillary tube, and connecting pipe are all made of metal.

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