Device for taking out fractured conical threaded section in heat exchange tube and operation method

Abstract

The invention discloses a device for taking out a fractured conical thread section in a heat exchange tube and an operation method, and aims to solve the problem that a conical thread pulling head of a straight tube type heat exchanger is fractured and is taken out in a manner that the conical thread section is drilled by an electric hand drill or a thread taking device is mounted or the conical thread pulling head is loosened by reverse striking. The conical threaded section pulling head broken in the heat exchange pipe cannot be effectively taken out, the plate-shaped electrode is installed on a gun head of an electric spark machine, electric corrosion is conducted on a notch of the conical threaded section through the plate-shaped electrode, and the water outlet end of the water injection pipe is arranged close to the front end of the plate-shaped electrode. The method is realized according to the following steps of: 1, fixing a gun head of an electric spark machine on a tube plate; 2, selecting a plate-shaped electrode made of a brass material; thirdly, the plate-shaped electrode is clamped to a clamping nozzle of an electric discharge machine and fastened; 4, an electric spark machine gun head is started while injection is conducted; and fifthly, the straight-line-shaped notch is communicated, and the conical threaded section is taken out. The invention relates to the field of heat exchanger maintenance.

Description

Technical Field

[0001] The invention relates to a device and an operating method for removing a tapered thread section in a heat exchange tube, and in particular to a device and an operating method for removing a broken tapered thread section in a heat exchange tube. The invention relates to the field of heat exchanger maintenance. Background Art

[0002] During the installation of straight tube heat exchangers, it is often necessary to pull out and replace the heat exchange tubes with the specification of φ16×1.4BFe30. For the pulling out work, a special tapered thread puller is used. The tapered thread on it is screwed with the heat exchange tube by external force, and then the puller is pulled out by the action of hydraulic pressure. Due to the influence of factors such as the material of the tapered thread puller, the bonding force between the heat exchange tube and the tube sheet, and the actual operation, the tapered thread puller occasionally breaks.

[0003] In the case where the tapered thread section is broken in the heat exchange tube, a hand drill is usually used to break the puller head, a thread remover is installed, or it is loosened by reverse hitting. However, since the material of the tapered thread section is spring steel 60Si2Mn, the material has high hardness and strong elasticity, and there is a large thread bite force with the heat exchange tube, but due to the small inner diameter of the heat exchange tube, the deep position of the tapered thread section and the limited operating space, the tapered thread section broken in the heat exchange tube cannot be removed, affecting subsequent work. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that the broken conical thread head of a straight tube heat exchanger can be removed by drilling the conical thread segment with an electric hand drill, installing a thread remover, or hitting it in the reverse direction to loosen it, but the broken conical thread head in the heat exchange tube cannot be effectively removed, which affects the normal progress of subsequent work, and further provides a device and an operating method for removing the broken conical thread segment in the heat exchange tube.

[0005] The technical solution adopted by the present invention to solve the above problems is:

[0006] A device for removing a broken conical thread section in a heat exchange tube comprises a cutting device and a water injection pipe; the cutting device comprises an electric spark machine gun head and a plate electrode; the plate electrode is installed on the electric spark machine gun head, and the conical thread section is electro-etched through the plate electrode, and the water outlet end of the water injection pipe is arranged close to the front end of the plate electrode.

[0007] Furthermore, the cutting equipment also includes a magnetic support for the machine head and an EDM machine nozzle; the EDM machine gun head is installed on the tube plate through the magnetic support for the machine head, the EDM machine nozzle is installed at the front end of the EDM machine gun head, and the plate electrode is installed on the EDM machine nozzle.

[0008] Furthermore, the plate-shaped electrode is a plate-shaped electrode made of brass material, and the thickness of the plate-shaped electrode is 2 mm.

[0009] An operating method for removing a broken conical thread section in a heat exchange tube, the method is implemented according to the following steps:

[0010] Step 1: Fix the EDM machine gun head on the tube sheet through the machine head with a magnetic bracket;

[0011] Step 2: Select a 2mm thick brass plate electrode as the electrode material for opening a straight-shaped notch;

[0012] Step 3: Clamp the plate electrode onto the EDM machine nozzle and tighten it. Confirm the position of the plate electrode by adjusting the position of the EDM machine gun head so that the plate electrode is located in the center of the tube.

[0013] Step 4: Inject tap water into the water injection pipe and start the EDM gun head at the same time. Through the repeated advance and retreat of the plate electrode, a straight-shaped notch is punched in the tapered thread section near the pipe wall. With the help of running water, the eroded powder is taken out of the pipe to avoid accumulation that affects the normal operation of the plate brass electrode.

[0014] Step 5: When the straight notch passes through the tapered thread section, the bite force between the tapered thread section and the BFe30 heat exchange tube will be released, and the loosened tapered thread section will be loosened and removed.

[0015] Furthermore, after the straight-shaped notch in step five passes through the tapered thread segment, the loosened tapered thread segment is loosened and removed by using a straight-blade screwdriver in conjunction with a wrench.

[0016] Beneficial effects of the present invention:

[0017] 1. The present application uses a method of high-temperature electrospark melting to open a straight-shaped notch on the tapered thread segment, thereby releasing the bite force between the tapered thread segment and the inner wall of the heat exchange tube, and then uses a straight-blade flat-head screwdriver and a wrench to loosen and remove the loosened tapered thread segment, thereby ensuring the orderly progress of subsequent work and reducing damage to the bottom hole of the tube plate.

[0018] Second, by using the process of electric spark erosion to remove materials, a straight-shaped notch is punched in the tapered thread segment. When the thread engagement depth is exceeded, the bonding force between the tapered thread segment and the heat exchange tube is released. Then, with the help of other simple flat tools such as a screwdriver, the tapered thread segment is loosened by rotation until it is removed. This method solves the problem of tapered thread segments remaining in small-diameter heat exchange tubes that are too deep to be removed by conventional methods. The effect has been good in practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of a straight tube double tube sheet heat exchanger.

[0020] Figure 2 Schematic diagram of the tapered thread segment before fracture.

[0021] Figure 3 Schematic diagram of the tapered thread segment after fracture.

[0022] Figure 4 This is a physical picture of the end face of a deep hole threaded cone section.

[0023] Figure 5 This is a real picture of the notch being etched away in the deep hole thread cone section.

[0024] Figure 6 This is a physical picture of the deep hole thread cone section that has been removed.

[0025] Figure 7 Schematic diagram of installation on tube sheet for this application.

[0026] Figure 8 This is a schematic diagram of the overall structure of this application.

[0027] Fig. 9 It is a structural diagram of the plate electrode 4.

[0028] Fig.10 Actual photo of the tooling used to prepare the opening for etching away the tapered thread segment. DETAILED DESCRIPTION

[0029] Specific implementation method 1: Combination Figure 7-Figure 9 The present embodiment is described as a device for removing broken conical thread segments in a heat exchange tube, which includes a cutting device and a water injection pipe 5; the cutting device includes an electric spark gun head 1 and a plate electrode 4; the plate electrode 4 is installed on the electric spark gun head 1, and the conical thread segments are electro-etched by the plate electrode 4, and the water outlet end of the water injection pipe 5 is arranged close to the front end of the plate electrode 4.

[0030] Electrospark machining is based on the high temperature erosion of the workpiece surface material generated by the instantaneous spark discharge between the tool electrode and the workpiece electrode. This machining method utilizes the conversion of electrical energy to thermal energy, and generates local high temperature on the workpiece surface through pulse discharge, so that the material on the workpiece surface melts or even vaporizes, and is thus eroded. The material of the tapered thread section is spring steel, which is an iron-based material with electrical conductivity, and is engaged with the BFe30 heat exchange tube, and forms a conductive circuit with the tool electrode clamped on the EDM machine gun head 1, which has the conditions for implementing electrospark erosion of materials. A straight-line notch can be made on the tapered thread section to release the engagement force between the tapered thread section and the inner wall of the heat exchange tube, and then other tools such as a screwdriver can be used to remove the residue.

[0031] Specific implementation method 2: Combination Figure 7-Figure 9The present embodiment is described. The present embodiment is a device for removing a broken conical thread section in a heat exchange tube, characterized in that: the cutting device further comprises a head magnetic support 2 and an EDM machine nozzle 3; the EDM machine gun head 1 is mounted on the tube sheet through the head magnetic support 2, the EDM machine nozzle 3 is mounted on the front end of the EDM machine gun head 1, and the plate electrode 4 is mounted on the EDM machine nozzle 3. Other methods are the same as those in the first specific embodiment.

[0032] Specific implementation method three: Combination Figure 7-Figure 9 The present embodiment is described as follows: the device for removing a broken conical threaded section in a heat exchange tube is characterized in that the plate-shaped electrode 4 is made of brass material and has a thickness of 2 mm. Other methods are the same as those of the second embodiment.

[0033] Specific implementation method 4: Combination 1- Fig.10 The present embodiment is described. The present embodiment is an operating method for removing a broken conical threaded section in a heat exchange tube, characterized in that the method is implemented according to the following steps:

[0034] Step 1: Fix the EDM machine gun head 1 on the tube sheet through the machine head magnetic bracket 2;

[0035] Step 2: Select a 2mm thick brass plate electrode 4 as the electrode material for opening a straight-line notch;

[0036] Step 3: Clamp the plate electrode 4 onto the EDM machine nozzle 3 and tighten it, and confirm the position of the plate electrode 4 by adjusting the position of the EDM machine gun head 1 so that the plate electrode 4 is located at the center of the tube;

[0037] Step 4: Inject tap water into the water injection pipe 5 and start the EDM gun head 1 at the same time. The plate electrode 4 is repeatedly moved forward and backward to punch a straight-line notch on the tapered thread section near the pipe wall. The eroded powder is taken out of the pipe with the help of running water to avoid accumulation that affects the normal operation of the plate brass electrode.

[0038] Step 5: When the straight notch passes through the tapered thread section, the bite force between the tapered thread section and the BFe30 heat exchange tube will be released, and the loosened tapered thread section will be loosened and removed.

[0039] Specific implementation method five: Combination 1- Fig.10 This embodiment is described. The method for operating a device for removing a broken tapered thread segment in a heat exchange tube described in this embodiment is characterized in that: after the straight-shaped notch passes through the tapered thread segment in step 5, the loosened tapered thread segment is loosened and removed by using a straight-blade screwdriver and a wrench. Other methods are the same as those in the fourth embodiment.

[0040] The above-mentioned specific implementation can be partially adjusted in different ways by those skilled in the art without departing from the principle and purpose of the present invention. The protection scope of the present invention shall be based on the claims and shall not be limited by the above-mentioned specific implementation. Each implementation scheme within its scope shall be subject to the constraints of the present invention.

Claims

1. A device for removing a broken tapered thread section in a heat exchange tube, characterized in that: It comprises a cutting device and a water injection pipe (5); the cutting device comprises an electric spark machine gun head (1) and a plate-shaped electrode (4); the plate-shaped electrode (4) is mounted on the electric spark machine gun head (1), and the conical threaded section is electro-etched by the plate-shaped electrode (4); the water outlet end of the water injection pipe (5) is arranged close to the front end of the plate-shaped electrode (4).

2. The device for removing a broken conical thread section in a heat exchange tube according to claim 1, characterized in that: The cutting device also includes a machine head magnetic support (2) and an electric spark machine nozzle (3); the electric spark machine gun head (1) is installed on the tube plate through the machine head magnetic support (2), the electric spark machine nozzle (3) is installed at the front end of the electric spark machine gun head (1), and the plate electrode (4) is installed on the electric spark machine nozzle (3).

3. The device for removing a broken conical thread section in a heat exchange tube according to claim 2, characterized in that: The plate-shaped electrode (4) is a plate-shaped electrode (4) made of brass material, and the thickness of the plate-shaped electrode (4) is 2 mm.

4. The method for operating the device for removing the broken conical threaded section in the heat exchange tube according to any one of claims 1 to 3, characterized in that: The method is implemented according to the following steps: Step 1: Fix the EDM machine gun head (1) on the tube plate through the machine head magnetic bracket (2); Step 2: Select a 2 mm thick brass plate electrode (4) as the electrode material for opening a straight-line notch; Step 3: Clamp the plate-shaped electrode (4) onto the EDM machine nozzle (3) and tighten it, and confirm the position of the plate-shaped electrode (4) by adjusting the position of the EDM machine gun head (1) so that the plate-shaped electrode (4) is located at the center of the tube; Step 4: Inject tap water into the water injection pipe (5) and start the electric spark gun head (1) at the same time. The plate electrode (4) is repeatedly moved forward and backward to punch a straight-line notch in the tapered thread section near the pipe wall. The eroded powder is taken out of the pipe with the help of running water to avoid accumulation that affects the normal operation of the plate brass electrode. Step 5: When the straight notch passes through the tapered thread section, the bite force between the tapered thread section and the BFe30 heat exchange tube will be released, and the loosened tapered thread section will be loosened and removed.

5. The method for operating the device for removing a broken conical thread section in a heat exchange tube according to claim 4, characterized in that: After the straight-shaped notch passes through the tapered thread section in step 5, the loosened tapered thread section is loosened and removed by using a straight-blade screwdriver and a wrench.

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