Evaporator U-shaped pipe and straight pipe connecting structure and welding method

Abstract

The invention relates to an evaporator U-shaped pipe and straight pipe connecting structure and a welding method. The evaporator U-shaped pipe and straight pipe connecting structure is characterized by comprising a U-shaped pipe and a straight pipe; the inner wall of the pipe opening of the U-shaped pipe is of a two-section inclined structure, the first inclined section is designed to have the inclination angle of 0.5-2 degrees, the inclination angle design can cover the tolerance range of the straight pipe, it is prevented that part of the straight pipe is difficult to embed into the U-shaped pipe, the end of the straight pipe can be better inserted and connected, and the service life of the straight pipe is prolonged. During brazing, it can be guaranteed that a large amount of brazing penetration liquid permeates into the gap between the straight pipe and the U-shaped pipe, the contact area of the brazing ring between the U-shaped pipe and the straight pipe after the brazing ring is fused is increased, the filling depth of brazing filler metal is guaranteed, and the welding strength and the sealing performance are improved; according to the design of the inclination angle of 20-40 degrees of the second inclined section, the U-shaped pipe embedded into the straight pipe is guided, meanwhile, the brazing ring can be supported, the situation that the brazing ring is too large in inner diameter and falls onto the U-shaped pipe is avoided, meanwhile, the situation that the brazing filling depth of the outer wall of the straight pipe and the inner wall of the U-shaped pipe is insufficient due to the fact that liquid overflows from the outer side after the brazing ring is molten can be prevented, and waste of brazing materials is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pipe welding, in particular to a connecting structure and welding method of an evaporator U-shaped pipe and a straight pipe. BACKGROUND

[0002] The evaporator is provided with a plurality of S-shaped evaporator pipes, and the production and processing generally adopts the following method: first, embed the straight copper pipes in an array in the evaporator box, with the two ends of the copper straight pipes extending out of the evaporator box; then, connect two adjacent copper straight pipes by using a U-shaped pipe at both ends of the evaporator box to realize the continuous communication of the evaporator pipes. However, the conventional connection of the evaporator U-shaped pipe and the straight pipe generally adopts manual welding, and the connection is achieved by using a simple nesting form and brazing. This method has low welding efficiency. For automatic welding, the conventional connection method of the U-shaped pipe and the straight pipe cannot meet the assembly requirements of automatic welding. SUMMARY

[0003] The present application aims to solve the problem of the traditional evaporator U-shaped pipe and straight pipe connection structure which is not conducive to automatic welding processing.

[0004] To solve the above technical problems, the technical solution of the present application is as follows: a connecting structure of an evaporator U-shaped pipe and a straight pipe, the innovation point of which is that the connecting structure comprises a U-shaped pipe and a straight pipe. The port position of the U-shaped pipe is flared for embedding the end of the straight pipe. The flared position of the U-shaped pipe comprises a first inclined section and a second inclined section. The first inclined section is located below the second inclined section. The inner wall of the first inclined section forms a first inclination angle with the vertical direction. The inner wall of the second inclined section forms a second inclination angle with the vertical direction, and the first inclination angle is smaller than the second inclination angle. The straight pipe is embedded in the U-shaped pipe and connected by brazing.

[0005] Further, the lower part of the first inclined section is a straight section, and the straight pipe outer wall and the U-shaped pipe straight section inner wall are connected by interference fit.

[0006] Further, the first inclination angle of the first inclined section is 0.5°-2°. The first inclination angle of the first inclined section facilitates the penetration of the molten brazing ring, improves the contact surface between the straight pipe and the U-shaped pipe during welding, and ensures the welding effect.

[0007] Further, the second inclination angle of the second inclined section is 20°-40°. The second inclination angle of the second inclined section forms a horn-shaped structure for supporting the brazing ring.

[0008] A welding method for connecting an evaporator U-shaped pipe and a straight pipe, the innovation point of which is as follows: S1: several brazing rings with a diameter of 1.2-1.8mm are nested on the straight pipe, then the end of the straight pipe is pressed into the pipe opening position of the U-shaped pipe, and the straight pipe is placed on the bottom and the U-shaped pipe is placed on the top; the brazing ring is supported by the horn-shaped opening of the pipe opening position of the U-shaped pipe; S2: the bottom of the U-shaped pipe is supported by the support structure to prevent the U-shaped pipe and the straight pipe from loosening and falling off due to brazing heating; S3: the joint of the U-shaped pipe and the straight pipe is inductively heated by the brazing induction heating ring, so that the brazing ring melts and penetrates into the gap between the inner wall of the U-shaped pipe and the outer wall of the straight pipe, waits for cooling and fixation, and realizes the brazing connection of the U-shaped pipe and the straight pipe; S4: the pipeline formed by the brazed U-shaped pipe and straight pipe is detected by brazing filling depth sampling and subjected to pressure test to detect whether it leaks; S5: the leakage area is marked and concentrated repair welding is carried out, and finally the finished product is output after passing the second detection.

[0009] Further, the support structure in S2 includes a support base, a brazing induction ring, a spring cylinder, a support spring and a support seat; the support base is L-shaped and fixedly installed on a driving source, and the support base is moved in the vertical direction and the horizontal direction by the driving source; the brazing induction ring is installed on the upper surface of the support base, and a brazing area is formed between the brazing induction ring and the upper surface of the support base; the spring cylinder is arranged on the upper surface of the support base, and the support spring is arranged in the spring cylinder; the support seat is installed at the top end of the support spring, and the support seat is supported by the elastic potential energy of the support spring to realize the flexible contact of the support seat and the bottom end of the U-shaped pipe.

[0010] Further, the brazing ring has at least two and is nested on the straight pipe, and the brazing ring is nested on the straight pipe in a small-diameter and large-quantity structure, which facilitates the rapid heating and penetration of the brazing ring, improves the welding efficiency and reduces the energy consumption.

[0011] The advantages of the present application are: 1) The inner wall of the pipe opening of the U-shaped pipe in the application adopts a two-section inclined structure design. The 0.5°-2° inclination of the first inclined section can cover the tolerance range of the straight pipe, prevent some straight pipes from being difficult to embed into the U-shaped pipe, achieve better insertion and connection of the end of the straight pipe, and ensure that a large amount of brazing penetration liquid can penetrate into the gap between the straight pipe and the U-shaped pipe during brazing, increase the contact area between the U-shaped pipe and the straight pipe after the brazing ring is melted, ensure the depth of the brazing filler, and increase the welding strength and sealing performance. In addition, the 20°-40° inclination of the second inclined section can facilitate the guidance of the U-shaped pipe embedded with the straight pipe and also support the brazing ring to prevent the inner diameter of the brazing ring from being too large and falling onto the U-shaped pipe, and prevent the liquid state of the brazing ring from overflowing from the outside after melting, which can cause insufficient brazing depth of the outer wall of the straight pipe and the inner wall of the U-shaped pipe, and reduce the waste of brazing material.

[0012] 2) When the U-shaped pipe in the application is used for inductive ring heating and melting of the brazing ring with the straight pipe, the support structure is in flexible contact with the bottom end of the U-shaped pipe. The support structure can prevent the pipe opening of the U-shaped pipe from expanding during heating, reduce the friction between the U-shaped pipe and the straight pipe, and cause the U-shaped pipe and the straight pipe to fall off or have reduced welding depth. In addition, the spring in the support structure can press the U-shaped pipe more tightly against the end of the straight pipe by the elastic potential energy of the spring, thereby avoiding the problem of insufficient connection depth when the U-shaped pipe is initially inserted into the straight pipe. BRIEF DESCRIPTION OF DRAWINGS

[0013] The application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0014] Fig. 1 The figure is a structure diagram of the evaporator U-shaped pipe of the application.

[0015] Fig. 2 The figure is a local enlarged structure diagram of the evaporator U-shaped pipe of the application.

[0016] Fig. 3 The figure is a support structure diagram of the connection method of the evaporator U-shaped pipe and the straight pipe of the application. DETAILED DESCRIPTION

[0017] To make the purpose, technical scheme and advantages of the embodiments of the application clearer, the technical scheme in the embodiments of the application will be described clearly and completely below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments. The components of the embodiments of the application described and shown in the accompanying drawings can be arranged and designed in various different configurations.

[0018] The following detailed description of embodiments of the application provided in the accompanying drawings is not intended to limit the scope of the application claimed, but merely represents selected embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the application.

[0019] As shown in Figs. 1 to 3 A U-shaped tube and straight tube connection structure of an evaporator, comprising a U-shaped tube 1 and a straight tube.

[0020] The port position of the U-shaped tube 1 is flared for embedding the end of the straight tube; the flared position of the U-shaped tube 1 comprises a first inclined section and a second inclined section; the first inclined section is below the second inclined section; the inner wall of the first inclined section forms a first inclination angle with the vertical direction; the inner wall of the second inclined section forms a second inclination angle with the vertical direction, and the first inclination angle is smaller than the second inclination angle.

[0021] The embedding of the straight tube in the U-shaped tube 1 is connected by brazing.

[0022] The straight section below the first inclined section is connected by interference fit between the outer wall of the straight tube and the inner wall of the straight section of the U-shaped tube.

[0023] The first inclination angle of the first inclined section is 0.5°-2°, and the setting of the first inclination angle of the first inclined section facilitates the penetration of the molten brazing ring, improves the contact surface of the straight tube and the U-shaped tube during welding, and ensures the welding effect.

[0024] The second inclination angle of the second inclined section is 20°-40°, and the setting of the second inclination angle of the second inclined section forms a horn-shaped structure for supporting the brazing ring.

[0025] A welding method for connecting a U-shaped tube and a straight tube of an evaporator, the specific welding method is as follows: S1: Nesting several brazing rings with a diameter of 1.2-1.8mm on the straight tube, then pressing the end of the straight tube into the port position of the U-shaped tube, using the placement method of the straight tube on top and the U-shaped tube on the bottom; using the horn-shaped opening of the port position of the U-shaped tube to support the brazing ring; S2: Using the support structure 2 to support the bottom of the U-shaped tube to prevent the U-shaped tube and the straight tube from loosening and falling off due to brazing heating; S3: Using a brazing induction heating coil to induce heat at the junction of the U-shaped tube and the straight tube, causing the brazing ring to melt and penetrate into the gap between the inner wall of the U-shaped tube and the outer wall of the straight tube, and waiting for cooling and fixation to realize the brazing connection of the U-shaped tube and the straight tube; S4: The pipeline formed by the brazed U-shaped tube and straight tube is detected by brazing depth sampling and subjected to pressure test to detect whether it leaks; S5: Mark the leakage area and concentrate repair welding, and finally perform product output after passing the second detection.

[0026] The support structure 2 in S2 comprises a support base 21, a brazing induction ring 22, a spring cylinder 23, a support spring and a holder 24; the support base 21 is in L-shaped structure and is fixedly installed on a driving source, and the support base is driven by the driving source to move in the vertical direction and the horizontal direction; the brazing induction ring 22 is installed on the upper surface of the support base 21, and a brazing area is formed between the brazing induction ring 22 and the upper surface of the support base 21; the spring cylinder 23 is arranged on the upper surface of the support base 21, and the support spring is arranged in the spring cylinder 23; the holder 24 is installed at the top end of the support spring, and the holder 24 is supported by the elastic potential energy of the support spring to realize the flexible contact of the holder 24 and the bottom end of the U-shaped tube.

[0027] The brazing ring is at least two and is nested on the straight pipe, the brazing ring adopts the structure of small diameter and large quantity to be nested on the straight pipe, the brazing ring is rapidly heated and penetrated, the welding efficiency is improved, and the energy consumption is reduced.

[0028] Those skilled in the art should understand that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only to illustrate the principles of the present application, and various changes and improvements can be made without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the present application.

Claims

1. A U-shaped tube and straight pipe connection structure for an evaporator, characterized in that it includes a U-shaped tube and a straight pipe; The U-shaped tube has an flared end for inserting the end of a straight tube; the flared end of the U-shaped tube includes a first inclined section and a second inclined section; the first inclined section is located below the second inclined section; the inner wall of the first inclined section forms a first angle with the vertical direction; the inner wall of the second inclined section forms a second angle with the vertical direction, and the first angle is smaller than the second angle. The straight tube is embedded inside the U-shaped tube and connected by brazing.

2. The evaporator U-shaped tube and straight tube connection structure according to claim 1, characterized in that: Below the first inclined section is a straight section, and the outer wall of the straight pipe and the inner wall of the straight section of the U-shaped pipe are connected by an interference fit.

3. The evaporator U-shaped tube and straight tube connection structure according to claim 1, characterized in that: The first tilt angle of the first inclined section is 0.5° to 2°. The setting of the first tilt angle of the first inclined section facilitates the penetration of the brazing ring after it melts, increases the contact surface between the straight pipe and the U-shaped pipe during welding, and ensures the welding effect.

4. The evaporator U-shaped tube and straight tube connection structure according to claim 1, characterized in that: The second tilt angle of the second inclined section is 20°–40°, and the second tilt angle of the second inclined section forms a trumpet-shaped structure to support the brazing ring.

5. A welding method for connecting a U-shaped tube and a straight tube in an evaporator, characterized in that: The specific welding method is as follows: S1: Place several brazing rings with a diameter of 1.2-1.8mm on the straight pipe, and then press the end of the straight pipe into the opening of the U-shaped pipe, with the straight pipe on top and the U-shaped pipe on the bottom; use the flared opening at the opening of the U-shaped pipe to support the brazing rings. S2: A support structure is used to support the bottom of the U-shaped tube to prevent the U-shaped tube from falling off due to the brazing heating process; S3: The brazing induction heating coil is used to induction heat the joint between the U-shaped tube and the straight tube, so that the brazing ring melts and penetrates into the gap between the inner wall of the U-shaped tube and the outer wall of the straight tube. After cooling and fixing, the brazing connection between the U-shaped tube and the straight tube is achieved. S4: The pipe formed by the brazed U-shaped pipe and the straight pipe is subjected to sampling inspection of the brazed fill depth and pressure test to check for leakage. S5: Mark the leaking area and repair it by welding. After passing the final second inspection, the finished product will be output.

6. The welding method for connecting an evaporator U-shaped tube and a straight tube according to claim 5, characterized in that: The support structure in S2 includes a support base, a brazing induction coil, a spring cylinder, a support spring, and a bracket. The support base is L-shaped and fixedly mounted on a drive source, which drives the support base to move in the vertical and horizontal directions. The brazing induction coil is mounted on the upper surface of the support base, and a brazing area is formed between the brazing induction coil and the upper surface of the support base. The spring cylinder is disposed on the upper surface of the support base, and the support spring is disposed inside the spring cylinder. The bracket is mounted on the top of the support spring, and the elastic potential energy of the support spring supports the bracket, achieving flexible contact between the bracket and the bottom end of the U-shaped tube.

7. The welding method for connecting an evaporator U-shaped tube and a straight tube according to claim 5, characterized in that: The brazing rings are at least two in number and nested on the straight pipe. The brazing rings adopt a small-diameter, multi-element structure nested on the straight pipe, which facilitates rapid heating and melting of the brazing rings, improves welding efficiency, and reduces energy consumption.

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