Heat exchanger with heat exchange tubes and tube plates in threaded connection

Abstract

A heat exchanger with a heat exchange tube and a tube plate in threaded connection is characterized by comprising the tube plate (1) with a threaded through hole, the heat exchange tube (2) with a threaded connector, a hollow bolt (3) with threads on two faces, a hollow stud (4) with threads on one face, a first sealing gasket (5.1) and a second sealing gasket (5.2). The internal thread of the hollow bolt is screwed with the external thread of the heat exchange tube, and the hollow stud is screwed with the internal thread of the heat exchange tube through the external thread; the first sealing gasket is additionally arranged between the outer side of the tube plate and the screw head of the hollow bolt, and the second sealing gasket is additionally arranged between the screw head of the hollow stud and the screw head of the hollow bolt. The connecting strength of the heat exchange tube and the tube plate of the fixed tube plate type heat exchanger is greatly improved, and equipment can be conveniently disassembled for maintenance work of overhauling and descaling.

Description

Technical Field

[0001] The utility model relates to the technical field of heat exchanger equipment, in particular to a heat exchange tube and tube sheet connection technology, specifically to a heat exchanger with a heat exchange tube and a tube sheet threadedly connected. Technical Background

[0002] Heat exchangers are important equipment in the chemical, petroleum, power, food and many other industries, and are widely used. Among the many types of heat exchangers, fixed tube sheet heat exchangers are relatively simple in structure, compact, and low in cost, so they are widely used. The disadvantage is that the outside of the tube cannot be cleaned mechanically, so the shell-side fluid must be clean and not easy to scale or corrode the shell.

[0003] At present, in fixed tube sheet heat exchangers, the main connection methods between heat exchange tubes and tube sheets are expansion, welding, or expansion plus welding. With this connection method, because the heat exchange tubes cannot be disassembled and cleaned, the medium cleanliness requirements are high. If the shell-side medium has high viscosity, is easy to scale, and is difficult to clean, it will seriously affect the normal operation of the heat exchanger and produce temperature difference stress of the heat exchange tubes, causing some heat exchange tubes to be damaged and fall off. In this case, the heat exchange tube fails and can only block the damaged heat exchange tube, resulting in reduced performance of the heat exchanger. If a detachable heat exchanger is used, the heat exchange tubes can be easily replaced, and even ordinary heat exchange tubes can be replaced with high-efficiency heat exchange tubes, which greatly improves the performance of the equipment and upgrades the equipment. Therefore, designing a heat exchanger with detachable heat exchange tubes will produce huge benefits.

[0004] For fixed tube sheet heat exchangers, since the inside and outside of the tubes are hot and cold fluids of different temperatures, it is particularly important to completely isolate the two media, especially in the chemical and petroleum industries. It is necessary to change the original welding and expansion methods, and at the same time, it is necessary to ensure the connection strength and sealing. It is also better to facilitate sealing detection, or to strengthen the sealing regularly.

[0005] Although the strength of threaded connection is higher than that of expansion joint and welding, the main limitation in the actual production process is that although the threaded fit is strong, it often leaks due to the gap between the threads. In addition, since the heat exchanger is generally large, the threaded fit requires rotating the heat exchange tube and the tube sheet. When the length and weight of the heat exchange tube are relatively large and the gap between the heat exchange tube and the baffle is relatively small, it is not realistic to achieve threaded fit by rotating the heat exchange tube. In addition, even if one side achieves threaded fit by rotating the heat exchange tube, it is not easy to achieve threaded fit by rotating the heat exchange tube on the other side. Even if the fit is completed, if the heat exchange tube and the tube sheet are not sealed and welded, there may be a risk of leakage. The above technical defects must be improved. Summary of the invention

[0006] The utility model aims to provide a heat exchanger with threaded connection between heat exchange tubes and tube sheets, in view of the problems that the existing heat exchange tubes and tube sheets are easily inconvenient to repair, replace and clean when they are connected by welding or expansion joints, and are prone to leakage when they are connected by threaded connection. Under the premise of ensuring the connection strength and sealing, the disassembly, repair and descaling of the fixed tube sheet heat exchanger can be easily realized.

[0007] The technical solution of the utility model is:

[0008] A heat exchanger with a heat exchange tube and a tube sheet connected by threads, characterized in that it comprises a tube sheet 1 with a threaded through hole, a heat exchange tube 2 with a threaded joint, a hollow bolt 3 with threads on both sides, a hollow stud 4 with a thread on one side, a first sealing gasket 5.1 and a second sealing gasket 5.2, the hollow bolt 3 is screwed to the internal thread of the tube sheet 1 through an external thread, the internal thread of the hollow bolt 3 is screwed to the external thread of the heat exchange tube 2, and the hollow stud 4 is screwed to the internal thread of the heat exchange tube 2 through an external thread; the first sealing gasket 5.1 is installed between the outer side of the tube sheet 1 and the screw head of the hollow bolt 3, and the second sealing gasket 5.2 is installed between the screw head of the hollow stud 4 and the screw head of the hollow bolt 3.

[0009] The main connection method of the utility model is to mechanically connect the heat exchange tube and the tube sheet by means of the matching clamping sealing gasket between the threads.

[0010] By clamping the sealing gasket through the cooperation of the threads, the heat exchange tube and the tube sheet are mechanically connected together, and the meshing strength between the threads can definitely be guaranteed in terms of stress resistance; although the connection strength between the threads is very high, there may be leakage between the threads. The utility model clamps the sealing gasket through the cooperation of the threads to seal the thread gap, thereby ensuring the sealing performance.

[0011] The utility model does not adopt the method of adding sealing gaskets inside for sealing, and the positions of two sealing gaskets are exposed on the surface, which is convenient for observation, and it is convenient to check the sealing condition regularly and replace them in time.

[0012] The heat exchange tubes of the utility model are detachable and connected to the tube sheet by mechanical clamping and sealing. All components do not deform, so all heat exchange tubes (or a single tube or part of them) can be loosened mechanically. During maintenance and parking, the fixed tube sheet heat exchanger can be disassembled for maintenance and descaling, and it is also convenient to regularly replace the sealing gasket.

[0013] The bolt root of the hollow bolt (3) has a chamfer that matches the inner inclination angle of the first sealing gasket (5.1).

[0014] The stud root of the hollow stud (4) has a chamfer that matches the inner inclination angle of the second sealing gasket (5.2).

[0015] The first sealing gasket (5.1) and the second sealing gasket (5.2) have the same structure. The inner diameter of half of their thickness is consistent with the corresponding hollow bolt (3) or hollow stud (4), and the other half of their thickness has an inner inclination angle that matches the chamfer of the root of the stud. There is a diameter difference between the inner inclination angle of the sealing gasket and the chamfer of the root of the stud. The aperture of the sealing gasket is smaller than the chamfer diameter of the root of the stud. Due to the diameter difference, an interference fit can be achieved when the sealing gasket is compressed, thereby enhancing the sealing performance of the sealing gasket.

[0016] The beneficial effects of the utility model are:

[0017] 1. By connecting through mechanical structure instead of welding, the requirements for manufacturing personnel and manufacturing equipment are reduced. There is no need to have skilled welding skills. The overall quality can be maintained by strictly following the assembly process requirements. There is no need to demand the welding technology of the manufacturing personnel or the advanced level of the welding equipment.

[0018] 2. Through the threaded connection, the fixed tube sheet can be disassembled for easy cleaning and maintenance, while ensuring the connection quality and sealing. In the working conditions where the fixed tube sheet heat exchanger cannot be used due to the easy scaling of the medium, the heat exchanger of the utility model can be used, which greatly saves equipment costs.

[0019] 3. Since the sealing gasket is mechanically clamped on the surface of the tube sheet, it is convenient to check the sealing performance and replace it regularly, which can ensure the sealing performance of the equipment for a long time.

[0020] 4. The tube sheet and hollow bolts, as well as the hollow bolts and heat exchange tubes are mechanically connected through threaded engagement, which significantly improves the tensile stress resistance and reduces the possibility of the heat exchange tube falling off. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0022] Figure 2 This is a schematic diagram of a tube sheet with threaded holes of the utility model;

[0023] Figure 3 This is a schematic diagram of a heat exchange pipe joint of the utility model;

[0024] Figure 4 It is a schematic diagram of a hollow bolt with threads on both sides of the utility model;

[0025] Figure 5 It is a schematic diagram of a hollow stud with a thread on one side of the utility model;

[0026] Figure 6 It is a schematic diagram of the sealing gasket of the utility model;

[0027] Figure 7It is a schematic diagram of the cooperation between the hollow stud and the sealing gasket of the utility model. DETAILED DESCRIPTION

[0028] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0029] like Figure 1-7 shown.

[0030] A heat exchanger having a heat exchange tube and a tube sheet connected by threads, comprising a tube sheet 1 with threaded through holes, a heat exchange tube 2 with a threaded joint, a hollow bolt 3 with threads on both sides, a hollow stud 4 with threads on one side, a first sealing gasket 5.1 and a second sealing gasket 5.2, such as Figure 1 As shown, the hollow bolt 3 (such as Figure 4 ) through the external thread and the tube sheet 1 ( Figure 2 ) is screwed together, and the internal thread of the hollow bolt 3 is screwed together with the heat exchange tube 2 ( Figure 3 ) external threaded connection, hollow stud 4 (such as Figure 5 ) is screwed together with the internal thread of the heat exchange tube 2 through an external thread; the first sealing gasket 5.1 is installed between the outer side of the tube sheet 1 and the screw head of the hollow bolt 3, and the second sealing gasket 5.2 is installed between the screw head of the hollow stud 4 and the screw head of the hollow bolt 3.

[0031] The utility model adopts a structure in which a hollow bolt and a nut cooperate to clamp a sealing gasket, which ensures sealing performance and forms a thread fit without rotating the heat exchange tube.

[0032] The connection structure mainly includes a tube sheet 1 with threaded through holes, a heat exchange tube 2 with a threaded joint, a hollow bolt 3 with threads on both sides, a hollow stud 4 with a thread on one side, and a sealing gasket 5 (including a first sealing gasket 5.1 and a second sealing gasket 5.2 with the same structure and different sizes, such as Figure 5 as shown).

[0033] The tube sheet 1 is evenly distributed with heat exchange tube holes, which have appropriate hole diameters and internal threads, and the thread pitch is determined according to the material and thickness of the tube sheet.

[0034] Both ends of the heat exchange tube 2 have threads of a certain length inside and outside, and the pitch is determined by the material and thickness of the tube sheet. Generally, the outer thread length of the heat exchange tube should not be less than the hollow bolt 3 with inner and outer threads, and the inner thread length of the heat exchange tube is determined according to the connection strength.

[0035] The inner thread of the hollow bolt 3 with threads on both sides can be closely matched with the outer thread of the heat exchange tube 2, and the outer surface can be closely matched with the threaded through hole of the tube sheet 1, and the root has a chamfer that is consistent with the angle of the sealing gasket 5.1; Figure 7 shown.

[0036] The outer thread of the single-sided threaded hollow stud 4 can be tightly matched with the inner thread of the heat exchange tube 2, and the root has a chamfer that is consistent with the angle of the sealing gasket 5.2; Figure 7 shown.

[0037] The sealing gaskets 5.1 and 5.2 described above have an inner diameter of half the thickness that is consistent with that of the hollow bolt and the hollow stud, and the other half of the length has a chamfer that is consistent with the angle of the root of the hollow bolt and the hollow stud, and there is a certain diameter difference between the chamfer of the sealing gasket and the chamfer of the root of the stud; the diameter of the sealing gasket is slightly smaller than the chamfer diameter of the root of the stud; through the diameter difference, an interference fit can be achieved when the sealing gasket is compressed, thereby enhancing the sealing performance of the sealing gasket.

[0038] The method of using the utility model is:

[0039] Taking the assembly of the heat exchange tube and the tube sheet on one side as an example, first, the heat exchange tube 2 with a threaded joint passes through the threaded hole of the tube sheet 1 with a threaded through hole, and a part of it extends out. At this time, the hollow bolt 3 with threads on both sides is rotated by a tool, and the inner and outer threads of the hollow bolt 3 are tightly combined with the outer threads of the heat exchange tube 2 and the inner threads of the tube sheet 1 respectively, and the first sealing gasket 5.1 is compressed; then the hollow stud 4 with threads on one side is rotated by a tool, and the outer threads of the hollow stud 4 are tightly combined with the inner threads of the heat exchange tube 2, and the second sealing gasket 5.2 is compressed; because the sealing gasket is elastic, when the sealing gasket is not compressed, the hollow bolt and the hollow stud can pass through the sealing gasket with a slightly smaller inner diameter; when the sealing gasket is compressed, it can have a good sealing effect on the gap between the threads and between the sealing gasket and the hollow bolt and the hollow stud.

[0040] By performing the above operations on all heat exchange tubes according to this process, the connection between the tube sheet and the heat exchange tube on one side can be achieved. Similarly, by performing the above operations on the heat exchange tube and tube sheet on the other side, the mechanical connection and sealing of the heat exchange tube and tube sheet of the entire heat exchanger can be achieved. When maintenance and descaling are required, the above steps can be reversed for disassembly.

[0041] The parts not involved in the present invention are the same as the prior art or can be implemented by using the prior art.

Claims

1. A heat exchanger with a heat exchange tube and a tube sheet threadedly connected, characterized in that: It comprises a tube sheet (1) with threaded through holes, a heat exchange tube (2) with a threaded joint, a hollow bolt (3) with threads on both sides, a hollow stud (4) with a thread on one side, a first sealing gasket (5.1) and a second sealing gasket (5.2); the hollow bolt (3) is screwed to the internal thread of the tube sheet (1) via an external thread, the internal thread of the hollow bolt (3) is screwed to the external thread of the heat exchange tube (2), and the hollow stud (4) is screwed to the internal thread of the heat exchange tube (2) via an external thread; the first sealing gasket (5.1) is installed between the outer side of the tube sheet (1) and the screw head of the hollow bolt (3), and the second sealing gasket (5.2) is installed between the screw head of the hollow stud (4) and the screw head of the hollow bolt (3).

2. The heat exchanger with heat exchange tubes and tube sheets threadedly connected according to claim 1 is characterized in that: The pitch of the internal thread on the tube sheet (1) matches the external thread of the hollow bolt (3).

3. The heat exchanger with heat exchange tubes and tube sheets threadedly connected according to claim 1, characterized in that: The pitch of the internal and external threads at both ends of the heat exchange tube (2) is determined according to the material and thickness of the tube sheet (1), and the length of the external thread is not less than the length of the hollow bolt (3).

4. The heat exchanger with heat exchange tubes and tube sheets threadedly connected according to claim 1, characterized in that: The bolt root of the hollow bolt (3) has a chamfer that matches the inner inclination angle of the first sealing gasket (5.1).

5. The heat exchanger with heat exchange tubes and tube sheets threadedly connected according to claim 1, characterized in that: The stud root of the hollow stud (4) has a chamfer that matches the inner inclination angle of the second sealing gasket (5.2).

6. The heat exchanger with heat exchange tubes and tube sheets threadedly connected according to claim 1, characterized in that: The first sealing gasket (5.1) and the second sealing gasket (5.2) have the same structure. The inner diameter of half of their thickness is consistent with the corresponding hollow bolt (3) or hollow stud (4), and the other half of their thickness has an inner inclination angle that matches the chamfer of the root of the stud. There is a diameter difference between the inner inclination angle of the sealing gasket and the chamfer of the root of the stud. The aperture of the sealing gasket is smaller than the chamfer diameter of the root of the stud. Due to the diameter difference, an interference fit can be achieved when the sealing gasket is compressed, thereby enhancing the sealing performance of the sealing gasket.

Images