A tube end assembling method of a tube-and-shell heat exchanger with spring bracket

Abstract

A tube end assembly method of a tube bundle heat exchanger with spring bracket belongs to the technical field of tube bundle heat exchanger manufacturing. The method solves the problems of long assembly time and high labor cost of existing manual force assembly of spring and split pin. Two positioning through holes are drilled on one end of the heat exchange pipe, and the two positioning through holes are distributed along the radial direction of the heat exchange pipe; the heat exchange pipe is inserted into the tube plate; the tube end is welded and expanded; the spring is inserted into one end of the heat exchange pipe by using a spring insertion tool; the split pin is inserted into the two positioning through holes, and the tube end assembly is completed. By setting the spring insertion tool and optimizing the process, the labor and assembly time are greatly saved, the heat exchanger tube end assembly time can be controlled within 30 seconds per hole shrinkage, the huge production cycle and production time cost are saved, and the batch production of heat exchange pipe tube end with spring bracket type heat exchanger is possible.

Description

A method for assembling the tube ends of a shell-and-tube heat exchanger with spring brackets at the tube ends. Technical Field

[0001] This invention relates to a tube-end assembly method for a shell-and-tube heat exchanger with spring brackets at the tube ends, belonging to the field of shell-and-tube heat exchanger manufacturing technology. Background Technology

[0002] Heat exchangers with spring-loaded tube ends (as shown in Figure 4) require the insertion of springs into the heat exchange tubes and the insertion of cotter pins to secure the springs (as shown in Figure 5) during manufacturing. The springs and heat exchange tubes are tightly fitted, with the spring's outer diameter being at least 4mm larger than the inner diameter of the tube bore. Current assembly methods involve manual force to assemble the springs and cotter pins, a very difficult process. It is estimated that it takes about 10 minutes to assemble one tube bore, while a large shell-and-tube heat exchanger is expected to have up to 20,000 tube bores, resulting in a huge workload and high labor costs for tube end assembly. Therefore, a simpler method for assembling shell-and-tube heat exchangers with spring-loaded tube ends is urgently needed to save assembly time and labor. Summary of the Invention

[0003] The present invention aims to solve the above-mentioned technical problems and provides a tube end assembly method for a shell-and-tube heat exchanger with a spring bracket at the tube end.

[0004] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0005] Technical Solution 1: A method for assembling the tube ends of a shell-and-tube heat exchanger with spring brackets at the tube ends, comprising the following steps:

[0006] Step 1: Drill two positioning through holes at one end of the heat exchange tube, and the two positioning through holes are distributed radially along the heat exchange tube;

[0007] Step 2: Insert the heat exchange tubes into the tube sheet;

[0008] Step 3: Weld and expand the pipe ends;

[0009] Step 4: Use a spring insertion tool to insert the spring into one end of the heat exchange tube. The spring insertion tool includes an adjusting rod, a baffle, and a hand drill. One end of the adjusting rod has a U-shaped groove machined radially. The baffle is threaded into the middle of the adjusting rod. The other end of the adjusting rod is fixed to the power output end of the hand drill. When installing the spring, first adjust the position of the baffle on the adjusting rod according to the required insertion depth of the spring into the heat exchange tube. Then, put the spring on one end of the adjusting rod and clamp the tail of the spring into the U-shaped groove. Then, start the hand drill to rotate the adjusting rod, which in turn causes the spring to undergo elastic deformation. As the adjusting rod rotates, the outer diameter of the spring gradually decreases to facilitate insertion into the heat exchange tube. When the baffle contacts the end of the heat exchange tube, turn off the hand drill. The adjusting rod stops rotating, the spring returns to its original state, and the outer diameter gradually increases to fit tightly against the inner wall of the heat exchange tube. Finally, remove the adjusting rod from the heat exchange tube. The installation of the spring in one heat exchange tube is now complete.

[0010] Step 5: Insert the cotter pins into the two positioning through holes to complete the pipe end assembly.

[0011] Furthermore, several tube holes are evenly distributed on the tube sheet. In step two, after the heat exchange tube is inserted into the tube sheet, the circumferential angle of the heat exchange tube is adjusted by adjusting the tube end tool so that after the cotter pin is installed in the two positioning through holes, the two ends of the cotter pin are respectively located at the hole bridge connection between the two tube holes on the same side.

[0012] Technical Solution 2: A pipe end adjustment fixture used in the above assembly method includes a cylindrical section and a rotating lever arm, wherein the outer wall of the cylindrical section is stepped, and two notches are opened along its radial direction on its small diameter section, and the rotating lever arm is fixedly installed on the large diameter section of the cylindrical section.

[0013] Furthermore, the rotating lever arm is arranged radially along the cylindrical section and its length is greater than the diameter of the cylindrical section.

[0014] Furthermore, the rotating lever arm is fixed to the end of the large-diameter section of the cylindrical section.

[0015] Furthermore, the length of the smaller diameter section of the cylindrical section is set to be greater than the distance between the center axis of the positioning through hole on the heat exchange tube and one end of the heat exchange tube.

[0016] Technical Solution 3: A method for using the above-mentioned pipe end adjustment fixture: When adjusting the circumferential angle of the heat exchange tube, first install the cotter pin in the two positioning through holes at one end of the heat exchange tube, then insert the small-diameter section of the cylindrical section into one end of the heat exchange tube, and simultaneously lock the two notches on the small-diameter section outside the cotter pin. Manually or by external force, control the rotation arm to rotate, thereby driving the cylindrical section to rotate circumferentially, and then driving the heat exchange tube to rotate circumferentially, until the cotter pin on the heat exchange tube is adjusted to the required angle. Then, remove the pipe end adjustment fixture from the heat exchange tube and remove the cotter pin.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] Power the adjustment rod by using a hand drill. The adjustment rod has an external thread machined in the middle to facilitate the positioning of the baffle on the rod, thereby controlling the depth to which the spring is inserted into the heat exchange tube. Repeat this step to insert all the springs into all the heat exchange tubes.

[0019] By setting up spring insertion fixtures and optimizing the process, manpower and assembly time are greatly saved. The assembly time of the heat exchanger tube ends can be controlled to within 30 seconds for each hole, saving huge production cycle and production time costs, and making it possible to mass-produce heat exchangers with spring brackets at the tube ends. Attached Figure Description

[0020] Figure 1 is a three-dimensional structural diagram of the spring insertion fixture;

[0021] Figure 2 is a three-dimensional structural diagram of inserting a spring into a heat exchange tube using a spring insertion tool (electric drill not shown);

[0022] Figure 3 is a three-dimensional structural diagram of the pipe end adjustment fixture;

[0023] Figure 4 is a schematic diagram of a shell-and-tube heat exchanger with spring brackets at the tube ends.

[0024] Figure 5 is a schematic diagram showing the position of the spring inside the heat exchange tube;

[0025] Figure 6 is a schematic diagram of the angle distribution of cotter pins;

[0026] Figure 7 is a schematic diagram of the distribution of heat exchange tubes on the tube sheet (only a portion of the heat exchange tubes are shown).

[0027] In the picture:

[0028] 1. Heat exchange tube; 11. Positioning through hole; 2. Cotter pin; 3. Tube sheet; 4. Adjusting rod; 41. U-shaped through groove; 5. Baffle; 6. Cylindrical section; 61. Notch; 7. Rotating lever arm; 8. Spring. Detailed Implementation

[0029] Specific Implementation Method 1: This implementation method is described in conjunction with Figures 1 to 7. The technical solutions in the implementation method of the present invention are clearly and completely described. Obviously, the described implementation method is only a part of the implementation method of the present invention, and not all of the implementation method. Based on the implementation method of the present invention, all other implementation methods obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] It should be noted that the descriptions of "front," "rear," "left," "right," "inner," "outer," "left side," "right side," "upper part," "lower part," "top," and "bottom" in this invention are defined based on the orientation or positional relationships shown in the accompanying drawings. They are merely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the described structure must be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0031] In the description of this invention, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] A method for assembling the tube ends of a shell-and-tube heat exchanger with spring brackets at the tube ends includes the following steps:

[0033] Step 1: Drill two positioning through holes 11 at one end of the heat exchange tube 1, and the two positioning through holes 11 are radially distributed along the heat exchange tube 1; the positioning through holes 11 are used to install cotter pins 2.

[0034] Step 2: Insert heat exchange tube 1 into tube sheet 3;

[0035] Step 3: Weld and expand the pipe ends;

[0036] Step 4: Insert spring 8 into one end of heat exchange tube 1 using a spring insertion fixture. The spring insertion fixture includes an adjusting rod 4, a baffle 5, and a hand drill. One end of the adjusting rod 4 has a U-shaped through groove 41 machined radially therein. The baffle 5 is threaded into the middle of the adjusting rod 4. The other end of the adjusting rod 4 is fixed to the power output end of the hand drill. When installing spring 8, first adjust the position of the baffle 5 on the adjusting rod 4 according to the required insertion depth of spring 8 into heat exchange tube 1. Then, slip spring 8 onto one end of the adjusting rod 4 and secure the tail of spring 8 in place. The spring 8 is inserted into the U-shaped groove 41. Then, the electric drill is started, driving the adjusting rod 4 to rotate, which in turn causes the spring 8 to elastically deform. As the adjusting rod 4 rotates, the outer diameter of the spring 8 gradually decreases, allowing it to be smoothly inserted into the heat exchange tube 1. When the baffle 5 contacts the end of the heat exchange tube 1, the electric drill is turned off, the adjusting rod 4 stops rotating, and the spring 8 returns to its original state, with its outer diameter gradually increasing, thus tightly fitting against the inner wall of the heat exchange tube 1. Finally, the adjusting rod 4 is removed from the heat exchange tube 1, completing the installation of the spring 8 in one heat exchange tube 1. The electric drill provides rotational power to the adjusting rod 4. The adjusting rod 4 has an external thread machined in the middle to facilitate the position of the baffle 5 on the adjusting rod 4, thereby controlling the insertion depth of the spring 8 into the heat exchange tube 1. Repeating this step will allow all the springs 8 to be installed in all the heat exchange tubes 1.

[0037] Step 5: Insert the cotter pin 2 into the two positioning through holes 11 to complete the pipe end assembly.

[0038] By setting up spring insertion fixtures and optimizing the process, manpower and assembly time are greatly saved. The assembly time of the heat exchanger tube ends can be controlled to within 30 seconds for each hole, saving huge production cycle and production time costs, and making it possible to mass-produce heat exchangers with spring brackets at the tube ends.

[0039] Several tube holes are evenly distributed on the tube sheet 3. In step two, after the heat exchange tube 1 is inserted into the tube sheet 3, the circumferential angle of the heat exchange tube 1 is adjusted by adjusting the tube end tool so that the cotter pin 2 is installed in the two positioning through holes 11. The two ends of the cotter pin 2 are respectively located at the hole bridge connection between the two tube holes on the same side. The purpose of adjusting the circumferential angle of the heat exchange tube 1 is: with tens of thousands of heat exchange tubes 1 evenly distributed on the tube sheet 3, setting the two ends of the cotter pin 2 respectively at the hole bridge connection between the two tube holes on the same side ensures that the cotter pin 2 will not interfere and facilitates the installation of the cotter pin 2.

[0040] A tube end adjustment fixture used in the above assembly method includes a cylindrical section 6 and a rotating arm 7. The outer wall of the cylindrical section 6 is stepped, and two notches 61 are opened radially on its small diameter section. The rotating arm 7 is fixed on the large diameter section of the cylindrical section 6. When adjusting the circumferential angle of the heat exchange tube 1, the cotter pin 2 is first installed in the two positioning through holes 11 at one end of the heat exchange tube 1. Then, the small diameter section of the cylindrical section 6 is inserted into one end of the heat exchange tube 1, and the two notches 61 on the small diameter section are locked outside the cotter pin 2. The rotating arm 7 is rotated manually or by external force, which drives the cylindrical section 6 to rotate circumferentially, thereby driving the heat exchange tube 1 to rotate circumferentially until the cotter pin 2 on the heat exchange tube 1 is adjusted to the required angle. Then, the tube end adjustment fixture is removed from the heat exchange tube 1, and the cotter pin 2 is removed.

[0041] The rotating lever arm 7 is arranged radially along the cylindrical section 6 and its length is greater than the diameter of the cylindrical section 6. With this design, the rotating lever arm 7 extending out of the cylindrical section 6 can be used as a handle, which makes it easier to adjust the circumferential angle of the heat exchange tube 1.

[0042] The rotating lever 7 is fixedly mounted at the large-diameter end of the cylindrical section 6. This design simplifies the structure of the pipe end adjustment fixture and makes it easier to manufacture.

[0043] The length of the smaller diameter section of the cylindrical section 6 is greater than the distance between the central axis of the positioning through hole 11 on the heat exchange tube 1 and one end of the heat exchange tube 1. This design ensures that the notch 61 can be engaged with the cotter pin 2.

[0044] A method for using the above-mentioned pipe end adjustment fixture: When adjusting the circumferential angle of the heat exchange tube 1, first install the cotter pin 2 in the two positioning through holes 11 at one end of the heat exchange tube 1, then insert the small diameter section of the cylindrical section 6 into one end of the heat exchange tube 1, and simultaneously lock the two notches 61 on the small diameter section outside the cotter pin 2. Manually or by external force control the rotation of the rotating arm 7 to drive the cylindrical section 6 to rotate circumferentially, thereby driving the heat exchange tube 1 to rotate circumferentially until the cotter pin 2 on the heat exchange tube 1 is adjusted to the required angle. Then, remove the pipe end adjustment fixture from the heat exchange tube 1 and remove the cotter pin 2.

[0045] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for assembling the tube ends of a shell-and-tube heat exchanger with spring brackets at the tube ends, characterized in that: The process includes the following steps: Step 1: Drill two positioning through holes (11) at one end of the heat exchange tube (1), and the two positioning through holes (11) are radially distributed along the heat exchange tube (1); Step 2: Insert the heat exchange tube (1) into the tube sheet (3); Step 3: Weld and expand the tube ends; Step 4: Insert the spring (8) into one end of the heat exchange tube (1) using a spring insertion fixture. The spring insertion fixture includes an adjusting rod (4), a baffle (5), and a hand drill. One end of the adjusting rod (4) is machined with a U-shaped through groove (41) along its radial direction. The baffle (5) is threadedly connected to the middle of the adjusting rod (4). The other end of the adjusting rod (4) is fixed to the power output end of the hand drill. When installing the spring (8), first adjust the baffle (5) on the adjusting rod (4) according to the required depth of the spring (8) inserted into the heat exchange tube (1). Position the spring (8) on the upper part of the tube, then place the spring (8) on one end of the adjusting rod (4) and insert the tail of the spring (8) into the U-shaped through groove (41). Then, start the electric drill to rotate the adjusting rod (4), which in turn causes the spring (8) to undergo elastic deformation. As the adjusting rod (4) rotates, the outer diameter of the spring (8) gradually decreases to smoothly insert into the heat exchange tube (1). When the baffle (5) contacts the end of the heat exchange tube (1), turn off the electric drill, the adjusting rod (4) stops rotating, the spring (8) returns to its original state, and the outer diameter gradually increases to fit tightly against the inner wall of the heat exchange tube (1). Finally, remove the adjusting rod (4) from the heat exchange tube (1), and the spring (8) in one heat exchange tube (1) is installed. Step 5: Insert the cotter pin (2) into the two positioning through holes (11) to complete the tube end assembly.

2. The tube end assembly method of a shell-and-tube heat exchanger with spring brackets at the tube ends according to claim 1, characterized in that: Several tube holes are evenly distributed on the tube sheet (3). In step two, after the heat exchange tube (1) is inserted into the tube sheet (3), the circumferential angle of the heat exchange tube (1) is adjusted by adjusting the tube end tool so that the cotter pin (2) is installed in the two positioning through holes (11) and the two ends of the cotter pin (2) are respectively located at the hole bridge connection between the two tube holes on the same side.

3. A pipe end adjustment fixture used in the assembly method of claim 2, characterized in that: It includes a cylindrical section (6) and a rotating lever (7), wherein the outer wall of the cylindrical section (6) is stepped, and two notches (61) are opened along its radial direction on its small diameter section, and the rotating lever (7) is fixed on the large diameter section of the cylindrical section (6).

4. The pipe end adjustment fixture according to claim 3, characterized in that: The rotating lever arm (7) is arranged radially along the cylindrical section (6) and its length is greater than the diameter of the cylindrical section (6).

5. The pipe end adjustment fixture according to claim 4, characterized in that: The rotating lever arm (7) is fixed to the end of the large-diameter section of the cylindrical section (6).

6. The pipe end adjustment fixture according to claim 3, characterized in that: The length of the small diameter section of the cylindrical section (6) is greater than the distance between the center axis of the positioning through hole (11) on the heat exchange tube (1) and one end of the heat exchange tube (1).

7. A method of using the pipe end adjustment fixture described in any one of claims 3 to 6, characterized in that: When adjusting the circumferential angle of the heat exchange tube (1), first install the cotter pin (2) in the two positioning through holes (11) at one end of the heat exchange tube (1), then insert the small diameter section of the cylindrical section (6) into one end of the heat exchange tube (1), and at the same time, clamp the two notches (61) on the small diameter section to the outside of the cotter pin (2). Manually or by external force control the rotating lever (7) to rotate, drive the cylindrical section (6) to rotate circumferentially, and then drive the heat exchange tube (1) to rotate circumferentially until the cotter pin (2) on the heat exchange tube (1) is adjusted to the required angle. Then, remove the tube end adjustment tool from the heat exchange tube (1) and remove the cotter pin (2).

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