Solid particle medium tube plate expanded connection method and device

Abstract

The invention belongs to the technical field of tube plate expanded connection, and discloses a solid particle medium tube plate expanded connection method and device. By means of cooperation of the stud and the nut, when the nut is rotated, the plunger moves upwards, solid particle media are compressed under limiting of the pressing plate, then pressure is applied to the high-pressure-resistant rubber ring wrapped in the pipe blank, the pipe blank is deformed through rubber, the pipe blank is tightly embedded into an annular groove formed in a plate hole, and a firm mechanical lock catch is formed; and the expanded connection process is completed. The invention solves the problems that the pipe wall is easy to damage and the surface quality is poor when the traditional pipe expander is used for connecting; the problem that the low-plasticity metal tube blank is difficult to deform due to expansion joint is solved, and the connection quality of the tube plate and the tube is effectively improved. The solid particle medium is used, and the high-pressure-resistant rubber is sleeved on the inner surface of the pipe blank, so that the wall thickness of the pipe blank is uniformly distributed during plastic deformation, the stress distribution is reasonable, and the connection quality is further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of tube sheet expansion, and in particular relates to a method and a device for expanding a tube sheet for a solid particle medium. Background Art

[0002] In many mechanical structures, it is often necessary to firmly connect plates and pipes. Traditional connection methods include welding, bolting, etc. However, welding connection may cause welding deformation and is inconvenient to operate in some occasions; bolt connection may have problems such as insufficient connection strength and looseness.

[0003] The connection between tube sheet and tube is a key step in the production of heat exchangers. The quality of the joint is the most important factor affecting the life of shell and tube heat exchangers. At present, the expansion process between tube blank and tube sheet includes hydraulic expansion and mechanical expansion. In the hydraulic expansion method, the tube is radially expanded by injecting high-pressure liquid into the inside of the tube. After the tube expands, it will fit tightly on the wall of the tube sheet hole, thus forming a firm connection. However, hydraulic expansion requires a special hydraulic system to provide high-pressure liquid, which is difficult to seal, and the equipment cost is relatively high. In addition, the equipment occupies a large space and has high maintenance and servicing costs. In the mechanical expansion process, by pushing the conical mandrel of the expander, the mandrel is pushed forward to push out the ball to press the inner wall of the heat exchange tube, and then the mechanical motor is started to rotate the mandrel with the ball. During the rotation process, the ball rolls the inner wall of the heat exchange tube, thinning the wall thickness of the heat exchange tube, causing plastic deformation, and achieving expansion and sealing of the heat exchange tube and the tube sheet. Although the tool is simple and easy to operate, mechanical expansion can easily damage the tube wall, resulting in poor surface quality of the tube wall, which may cause the tube to rupture and affect service performance.

[0004] In summary, the above processing methods have the problems of sealing difficulties, high equipment costs, or poor surface quality of the tube wall, which may cause the tube blank to rupture. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a solid particle medium tube sheet expansion method and device, which solves the problems of difficult sealing, high equipment cost, or poor tube wall surface quality in existing methods, which may cause tube blank rupture.

[0006] The present invention is achieved through the following technical solutions: The invention discloses a solid particle medium tube sheet expansion method, comprising the following steps: S1. According to the size and structure of the tube blank and the tube sheet to be connected, the pressing plate and the plunger are processed; one end of the plunger is a flat plate structure, and the other end has a thread; the inner wall of the hole of the tube sheet is processed with a plurality of annular grooves; S2. Set high pressure resistant rubber inside the tube blank; Install the sleeved tube into the tube sheet, with the lower end placed on the base; Place the plunger with the threaded end facing upward into the tube blank; Add solid granular medium into the cavity area between the plunger and the high-pressure rubber, then install the pressing plate to the top of the tube, install the nut on the plunger, and press it against the upper surface of the pressing plate; S3, rotating the nut to make the plunger move upward to squeeze the solid particle medium. Under the constraint of the pressing plate, pressure is applied to the high-pressure resistant rubber wrapped inside the tube blank. The high-pressure resistant rubber is deformed to squeeze the tube blank, and the tube blank is radially deformed at the position of the annular groove, thereby being embedded in the annular groove opened inside the tube plate. S4. When the tube blank is tightly embedded in the annular groove position inside the tube sheet, a stable lock is formed at the annular groove position of the tube sheet; S5. Rotate the nut until it is removed, and at the same time, the plunger moves downward to remove the pressing plate, the plunger and the solid particle medium to obtain a connecting piece formed by the tube blank and the tube sheet.

[0007] Furthermore, the rotational angular velocity ω of the nut is 1.5 to 3 rad / s.

[0008] The present invention also discloses a solid particle medium tube sheet expansion device for realizing the solid particle medium tube sheet expansion method, comprising a plunger, a pressing plate, a nut, a base and high pressure resistant rubber; One end of the plunger is a flat plate structure, and the other end has a thread; the inner wall of the hole of the tube sheet is processed with a number of annular grooves; When in use, the high-pressure resistant rubber sleeve is put inside the tube blank, the sleeved tube blank is installed inside the tube plate, and the lower end is placed on the base; The plunger with the threaded end facing upward is placed into the tube blank; the threaded end of the plunger is matched with the nut; Solid particle medium is added into the cavity area between the plunger and the high-pressure resistant rubber, the pressing plate is installed on the top of the tube blank, and the nut is pressed against the upper surface of the pressing plate.

[0009] Furthermore, the inner diameter of the pressure plate and the outer diameter of the plunger thread are clearance-matched.

[0010] Furthermore, the outer diameter of one end of the plunger plate is clearance-matched with the inner diameter of the tube blank covered with the high-pressure resistant rubber.

[0011] Furthermore, the solid particle medium is a high molecular weight polymer with a molecular weight of 25000 to 100000 g / mol, a particle size of 2 mm to 5 mm, and an elastic modulus of 0.2 to 1.2 GPa.

[0012] Furthermore, the depth d of the annular groove satisfies 1.5t<d<2t, the height h of the annular groove satisfies 5t<h<7t, and t is the thickness of the tube blank.

[0013] Furthermore, the transition position between the annular groove of the tube sheet and its inner wall has a fillet, and the fillet radius R=0.1h.

[0014] Furthermore, the pressing plate and the plunger are processed according to the size structure of the tube blank and the tube sheet to be connected.

[0015] Furthermore, the base is an annular base.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention discloses a method for expanding a tube sheet with solid particle media. The method is different from the traditional method, such as inserting a tube expander into the end of a tube blank and applying an external force to plastically deform the tube blank until it fits tightly with the tube sheet. Instead, the method uses the extrusion medium to make the medium a pressure transmission carrier, and the medium extrudes the tube material to cause the tube material to undergo plastic deformation and fit tightly in the groove opened inside the tube sheet hole to complete the expansion. At the same time, the medium is preferably solid particles, which have good flow properties and small volume compression. It is an environmentally friendly and energy-saving process, and is suitable for forming tubes with low plasticity and difficult-to-process materials. The method of inserting high-pressure resistant rubber into the inner surface of the tube blank solves the problem that solid particles are easily dispersed and difficult to collect during loading and unloading, and can optimize the stress state of the low-plasticity metal tube blank during the connection process between the tube sheet and the tube blank, and promote uniform deformation of the tube blank. The nut is rotated to make the plunger move upward to extrude the solid particle medium, and then the pressure on the medium is transmitted to the rubber sleeve, and then evenly applied to the tube blank. As the nut rotates more and more times, the plunger gradually moves upward, and the tube blank gradually fits tightly with the groove of the tube sheet to form a strong mechanical lock, thereby obtaining a connecting piece formed by the tube blank and the tube sheet.

[0017] Furthermore, when the number of annular grooves opened inside the tube sheet hole is greater than 1, the annular grooves are evenly distributed in the axial direction inside the tube blank where they are located, which can make the connection between the tube sheet and the tube more secure.

[0018] Furthermore, when tightening, ω is 1.5-3rad / s to ensure that the upward speed of the plunger is appropriate. If the speed is too small, the forming efficiency is low, and if the speed is too large, the deformation of the local action area of ​​the tube blank is insufficient.

[0019] Furthermore, the transition position between the annular groove of the tube sheet and its inner wall has a rounded corner, which can promote the flow of the tube sheet and effectively improve the connection force between the tube sheet and the tube.

[0020] The device disclosed in the present invention realizes the above-mentioned solid particle medium tube sheet expansion method, which utilizes a plunger and a nut to cooperate in extruding a solid particle medium, extruding a tube blank to make it plastically deformed, and then realizing the device of the method of connecting a tube and a tube sheet. The device has a reasonable design, a simple structure, and is easy to install. It has good compatibility with other equipment. According to the size structure of the tube sheet and the tube blank, after processing the corresponding plunger and the matching nut and the pressing plate, mass production can be realized. According to different tube blank materials, the process parameters and the speed of rotating the nut can be flexibly adjusted to improve the forming performance of different tube blanks.

[0021] The inner surface of the tube blank is covered with high-pressure resistant rubber, which solves the problem that solid particles are easily dispersed and difficult to collect during loading and unloading. At the same time, it optimizes the stress state of the low-plasticity metal tube blank during the connection process between the tube sheet and the tube blank, and promotes the uniform deformation of the tube blank. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of the solid particle medium tube sheet expansion joint device of the present invention; Figure 2 It is a partial enlarged view of the annular groove on the tube blank; Figure 3 It is a schematic diagram of the tube blank after expansion connection of the solid particle medium tube sheet expansion connection device of the present invention; Figure 4 It is a schematic diagram of the structure of removing the plunger after expansion; Figure 5 Schematic diagram of the mechanical locking structure formed to complete the connection between the tube sheet and the tube blank.

[0023] Among them, 1. nut; 2. pressure plate; 3. tube blank; 4. tube sheet; 5. high pressure resistant rubber; 6. solid particle medium; 7. plunger; 8. base. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, which are intended to explain the present invention rather than to limit it.

[0025] like Figure 1 , is a set of devices for realizing the solid particle medium tube sheet expansion method of the present invention. This example is used to specifically explain the solid particle medium tube sheet expansion method of the present invention, which does not constitute a limitation of the present invention. The method of the present invention can be realized by using any existing device that can realize its step-by-step functions.

[0026] like Figure 1 As shown, the device includes a plunger 7, a pressing plate 2, a tube blank 3, a tube sheet 4 and a nut 1; the plunger 7 is installed in the tube blank 3, and the top end extends out of the tube blank 3, and the solid particle medium 6 is added to the cavity area formed by the plunger 7 and the tube blank 3; the base 8 and the tube sheet 4 are sleeved on the outside of the tube blank 3 from bottom to top, the pressing plate 2 is placed on the top of the tube blank 3, and the nut 1 is close to the upper surface of the pressing plate 2 and is threadedly connected with the plunger 7.

[0027] One end of the plunger 7 is a flat plate structure, and the other end has a thread.

[0028] The nut 1 rotates under the action of the external circumferential angular velocity, driving the plunger to move upward and squeeze the solid particle medium. The structure and size of the pressing plate 2, the plunger 7 and the nut 1 are related to the structural size of the low-plasticity metal tube blank-tube sheet to be connected.

[0029] The inner surface of the tube blank 3 is covered with a high pressure resistant rubber 5 .

[0030] like Figure 2 As shown, the inner surface of the tube sheet 4 is prefabricated with a plurality of annular grooves.

[0031] The solid particle medium tube sheet ring expansion method of the present invention comprises: like Figure 1~Figure 5 , S1: according to the size and structure of the tube blank 3 and the tube sheet 4 to be connected, process the pressing plate 2, the plunger 7 and the matching nut 1; One end of the plunger 7 is a flat plate structure, and the other end has a thread; the inner wall of the hole of the tube sheet 4 is processed with a plurality of annular grooves; the high-pressure resistant rubber 5 is sleeved inside the tube blank 3; the tube blank 3 with the high-pressure resistant rubber 5 sleeved is installed inside the tube sheet 4, and the lower end is placed on the base 8; the plunger 7 with the threaded end facing upward is placed into the tube blank 3; after adding a sufficient amount of solid particle medium 6, the pressing plate 2 is installed on the upper side of the tube blank 3, and the nut 1 is installed on the plunger 7, while being pressed against the upper surface of the pressing plate 2.

[0032] S2: Figure 3 As shown, the nut 1 is rotated clockwise, so that the plunger 7 moves upward to squeeze the solid particle medium 6. Under the constraint of the pressing plate 2, pressure is applied to the high-pressure resistant rubber 5 wrapped inside the tube blank 3. The high-pressure resistant rubber 5 is deformed to squeeze the tube blank 3, and the tube blank 3 is radially deformed at the position of the annular groove, so that it is tightly embedded in the annular groove opened inside the hole of the tube plate 4. S3: When the tube blank 3 is tightly embedded in the annular groove position inside the tube sheet 4, a stable lock is formed at the annular groove position of the tube sheet 4; S4: Figure 4 As shown, the nut 1 is rotated counterclockwise until it is removed, and at the same time, the plunger 7 moves downward, and the pressing plate 2, the plunger 7 and the solid particle medium 6 are removed to obtain the following Figure 5 The tube blank 3 and the tube sheet 4 shown form a connecting piece.

[0033] In a preferred embodiment of the present invention, in S1, the inner diameter of the pressing plate 2 and the outer diameter of the plunger 7 thread are clearance matched; the outer diameter of one end of the plunger 7 plate and the inner diameter of the tube blank 3 covered with the high-pressure resistant rubber 5 are clearance matched.

[0034] In a preferred embodiment of the present invention, the solid particle medium 6 is a high molecular polymer with a molecular weight of 25,000 to 100,000 g / mol, such as polyethylene plastic solid particles, with a particle size of 2 mm to 5 mm and an elastic modulus of 0.75 to 0.89 GPa.

[0035] In a preferred embodiment of the present invention, the rotational angular velocity ω of the nut 1 is 2.5 rad / s.

[0036] In a preferred embodiment of the present invention, Figure 2As shown, the annular groove on the inner wall of the tube sheet 4 has a rounded corner at the transition position to its inner wall, the depth d of the annular groove should satisfy 1.5t<d<2t, the height h of the annular groove should satisfy 5t<h<7t, and the fillet radius R=0.1h.

[0037] Wherein, t is the thickness of the tube blank 3.

[0038] Example 1 The material of the tube blank 3 is 6061T6 aluminum alloy, and the tube sheet 4 is 304 stainless steel. When ω is selected to be 1.5-3rad / s during tightening, the upward speed of the plunger 7 is just right, so that the 6061T6 tube blank can undergo plastic deformation and completely fit the 304 stainless steel tube sheet 4, completing the expansion process without causing insufficient deformation of the local action area of ​​the tube blank 3.

[0039] The present invention adopts new polymer solid particles set in high-pressure resistant rubber 5 as pressure medium, and realizes compression of solid particle medium 6 by rotating plunger 7 to realize expansion connection between tube blank 3 and tube sheet 4. It has the advantages of simple device, no need for sealing, convenient operation, good compatibility of device, firm connection, uniform wall thickness distribution of tube blank 3, and not easy to fall off.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for expanding tube sheets of solid particle media, characterized in that: The following steps are involved: S1. According to the size and structure of the tube blank (3) and the tube sheet (4) to be connected, the pressing plate (2) and the plunger (7) are processed; one end of the plunger (7) is a flat plate structure, and the other end has a thread; and the inner wall of the hole of the tube sheet (4) is processed to have a plurality of annular grooves; S2, a high pressure resistant rubber (5) is installed inside the tube blank (3); Install the sleeved tube blank (3) inside the tube sheet (4) with the lower end placed on the base (8); Place the plunger (7) with the threaded end facing upward into the tube blank (3); A solid particle medium (6) is added into the cavity area between the plunger (7) and the high-pressure resistant rubber (5), and then the pressing plate (2) is installed on the top of the tube blank (3), and the nut (1) is installed on the plunger (7) while being pressed against the upper surface of the pressing plate (2); S3, rotating the nut (1) so that the plunger (7) moves upward to squeeze the solid particle medium (6), and under the constraint of the pressing plate (2), pressure is applied to the high-pressure resistant rubber (5) wrapped inside the tube blank (3), so that the high-pressure resistant rubber (5) is deformed and squeezes the tube blank (3), and the tube blank (3) is radially deformed at the position of the annular groove, thereby being embedded in the annular groove opened inside the tube plate (4); S4, when the tube blank (3) is tightly embedded in the annular groove position inside the tube sheet (4), a stable lock is formed at the annular groove position of the tube sheet (4); S5. Rotate the nut (1) until it is removed, and at the same time, move the plunger (7) downward to remove the pressing plate (2), the plunger (7) and the solid particle medium (6), thereby obtaining a connecting piece formed by the tube blank (3) and the tube sheet (4).

2. The solid particle medium tube sheet expansion method according to claim 1, characterized in that: The rotational angular velocity ω of the nut (1) is 1.5 to 3 rad / s.

3. A solid particle medium tube sheet expansion device for realizing the solid particle medium tube sheet expansion method according to claim 1 or 2, characterized in that: It comprises a plunger (7), a pressure plate (2), a nut (1), a base (8) and a high-pressure resistant rubber (5); One end of the plunger (7) is a flat plate structure, and the other end has a thread; the inner wall of the hole of the tube plate (4) is processed with a plurality of annular grooves; When in use, the high-pressure resistant rubber (5) is sleeved inside the tube blank (3), and the sleeved tube blank (3) is installed inside the tube plate (4), with the lower end placed on the base (8); The plunger (7) has one end with a thread facing upward and is placed in the tube blank (3); the threaded end of the plunger (7) is matched with the nut (1); A solid particle medium (6) is added into the cavity area between the plunger (7) and the high-pressure resistant rubber (5), the pressing plate (2) is installed on the top of the tube blank (3), and the nut (1) is pressed against the upper surface of the pressing plate (2).

4. The solid particle medium tube sheet expansion device according to claim 3 is characterized in that: The inner diameter of the pressure plate (2) and the outer diameter of the thread of the plunger (7) are clearance-matched.

5. The solid particle medium tube sheet expansion device according to claim 3, characterized in that: The outer diameter of one end of the plunger (7) plate is clearance-matched with the inner diameter of the tube blank (3) sleeved with the high-pressure resistant rubber (5).

6. The solid particle medium tube sheet expansion device according to claim 3, characterized in that: The solid particle medium (6) is a high molecular weight polymer with a molecular weight of 25000 to 100000 g / mol, a particle size of 2 mm to 5 mm, and an elastic modulus of 0.2 to 1.2 GPa.

7. The solid particle medium tube sheet expansion device according to claim 3, characterized in that: The depth d of the annular groove satisfies 1.5t<d<2t, and the height h of the annular groove satisfies 5t<h<7t, where t is the thickness of the tube blank (3).

8. The solid particle medium tube sheet expansion device according to claim 7, characterized in that: The transition position between the annular groove of the tube sheet (4) and its inner wall has a rounded corner, and the rounded corner radius R=0.1h.

9. The solid particle medium tube sheet expansion device according to claim 3, characterized in that: The pressing plate (2) and the plunger (7) are processed according to the size and structure of the tube blank (3) and the tube sheet (4) to be connected.

10. The solid particle medium tube sheet expansion device according to claim 3, characterized in that: The base (8) is a ring-shaped base.

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