阅读说明：本技术 换热管堵管方法 (Method for blocking heat exchange tube ) 是由 雒晓卫 吴莘馨 于 2018-08-17 设计创作，主要内容包括：本发明涉及热力工程技术领域,提供了一种换热管堵管方法。该方法包括以下步骤：预先在密封塞的外壁上加工环形凸台,在压紧塞的外壁上加工第一锁紧部；在换热管两端封堵处的内壁上加工用于与所述环形凸台接触配合的台阶面、以使所述换热管的管口内形成阶梯孔；在所述阶梯孔的大端上加工用于与所述第一锁紧部配合锁紧的第二锁紧部；将所述密封塞插入所述换热管,使所述环形凸台贴合在所述台阶面上；将压紧塞插入所述换热管,通过所述第一锁紧部与所述第二锁紧部配合锁紧,使所述环形凸台压紧所述台阶面；对所述压紧塞进行防松处理。本发明不仅可适用于处于高温环境以及内径较小的换热管,而且还无需打磨去除换热管与管板之间原有的密封焊缝。(The invention relates to the technical field of thermal engineering, and provides a method for blocking a heat exchange tube. The method comprises the following steps: processing an annular boss on the outer wall of the sealing plug in advance, and processing a first locking part on the outer wall of the pressing plug; step surfaces which are in contact fit with the annular bosses are machined on the inner walls of the plugging parts of the two ends of the heat exchange tube so as to form step holes in the tube orifice of the heat exchange tube; a second locking part matched and locked with the first locking part is machined at the large end of the stepped hole; inserting the sealing plug into the heat exchange tube to enable the annular boss to be attached to the step surface; inserting a compression plug into the heat exchange tube, and enabling the annular boss to compress the step surface through matching and locking of the first locking part and the second locking part; and carrying out anti-loosening treatment on the compaction plug. The invention is not only suitable for the heat exchange tube which is in a high-temperature environment and has a smaller inner diameter, but also does not need to polish and remove the original sealing weld joint between the heat exchange tube and the tube plate.)

1. A method for blocking a heat exchange tube is characterized by comprising the following steps:

processing an annular boss on the outer wall of the sealing plug in advance, and processing a first locking part on the outer wall of the pressing plug;

step surfaces which are in contact fit with the annular bosses are machined on the inner walls of the plugging parts of the two ends of the heat exchange tube so as to form step holes in the tube orifice of the heat exchange tube;

a second locking part matched and locked with the first locking part is machined at the large end of the stepped hole;

inserting the sealing plug into the heat exchange tube to enable the annular boss to be attached to the step surface;

inserting a compression plug into the heat exchange tube, and enabling the annular boss to compress the step surface through matching and locking of the first locking part and the second locking part;

and carrying out anti-loosening treatment on the compaction plug.

2. The method for plugging a heat exchange tube according to claim 1, wherein the first locking portion is an external thread provided on an outer wall of the compression plug, and the second locking portion is an internal thread provided on a large end of the stepped hole.

3. The method of plugging a heat exchange tube according to claim 2, wherein the length of the internal thread is smaller than the length of the large end of the stepped hole.

4. The method of plugging a heat exchange tube according to claim 2, wherein the top of the compression plug is provided with a driving site for engagement with an installation tool.

5. The method for plugging the heat exchange tube according to claim 4, wherein the driving position is a mounting hole formed at the top of the compression plug, and the mounting hole is used for being matched and connected with an inner angle wrench.

6. The method for plugging a heat exchange tube according to claim 5, wherein the cross-sectional shape of the mounting hole is a triangle, a quadrangle, a hexagon or an octagon.

7. The method for plugging the heat exchange tube according to claim 1, wherein the anti-loosening treatment is performed on the compression plug, specifically, a mechanical anti-loosening treatment is performed on the compression plug or a welding anti-loosening treatment is performed on the compression plug.

8. The method of plugging a heat exchange tube according to claim 1, wherein the compression plug is integrally formed with the sealing plug.

9. The method for plugging a heat exchange tube according to any one of claims 1 to 8, wherein a sealing layer is plated on the step surface.

10. The method for plugging a heat exchange tube according to any one of claims 1 to 8, wherein the step surface is a tapered surface.

Technical Field

The invention relates to the technical field of thermal engineering, in particular to a method for blocking a heat exchange tube.

Background

Heat exchangers are indispensable equipment in the fields of chemical industry, petrochemical industry, power generation and the like, and can be divided into heaters, coolers, evaporators, reboiling periods, condensers, waste heat boilers and the like according to different purposes of heat recovery of the heat exchangers. The heat exchange tube in the heat exchanger is easy to leak or thin due to welding quality defects, abrasion, stress corrosion, intergranular corrosion, flow-induced vibration, high-temperature creep and other reasons, and even the heat exchange media on the tube side and the shell side of the heat exchanger are mutually communicated. In order to ensure that the heat exchanger can continue to operate safely and stably, the heat exchange tube with the wall thickness reduced to a certain thickness and leakage must be plugged. The plugging technology commonly used at present has explosion plugging pipe, welding plugging pipe and mechanical plugging pipe, wherein:

the explosive plugging pipe is not used at present due to large residual stress and difficulty in controlling plugging quality.

The welded blocking pipe belongs to a permanent blocking pipe, although the cost of the blocking pipe is low, the effect of the blocking pipe directly depends on the quality of a welding seam, and the sealing welding seam is welded again after the sealing welding between the heat exchange pipe and the pipe plate is polished and removed during pipe blocking, particularly the heat exchanger adopting flush welding or inward concave welding. The method is generally limited by the field environment, and the radiographic inspection of the welding seam cannot be performed after the welding is finished, so that the quality of the field welding seam is difficult to ensure. In addition, in some cases, in order to reduce the residual stress of welding, it is necessary to perform post-welding heat treatment on the weld, and the heat treatment may affect the expansion, connection and removal force of the surrounding heat exchange tube. For example, in a high temperature gas cooled reactor steam generator, the heat exchange tube is made of T22, the tube plate is made of F22, and the heat treatment after welding is required for the sealing welding between the heat exchange tube and the tube plate. In order to not influence the pulling-out force of the expansion joint of the heat exchange tube during the postweld heat treatment, the postweld heat treatment of the seal welding is placed before the hydraulic expansion. If the tube is blocked by adopting a welding mode, the original sealing weld joint between the heat exchange tube and the tube plate needs to be polished and removed, and the sealing welding is carried out again. Thus, the following problems arise: 1) the quality of the sealing weld of the secondary welding is not easy to guarantee; 2) the ray detection of the welding seam cannot be implemented; 3) the postweld heat treatment of the weld cannot be performed, and even if the postweld heat treatment can be performed, the pulling-out force of the surrounding heat exchange tube is also affected.

Mechanical pipe plugging is generally divided into two ways: one is mechanical drawing type, and the other is mechanical roller expanding type. Although the mechanical pipe plugging has simple process flow, the pipe plug has a complex structure and is not suitable for a heat exchange pipe which is in a high-temperature environment and has a pipe wall which is too thick or the inner diameter of which is less than 16 mm. The main reason is that the inner diameter of the heat exchange tube directly affects the sizes of the pull rod and the roller, and the strength of the pull rod and the roller cannot meet the requirement due to the fact that the sizes of the pull rod and the roller are too small. In addition, under the high-temperature annular condition, due to the existence of creep deformation, the residual stress at the contact surface of the plug is reduced along with the increase of service time, and the sealing performance of the plug is further influenced.

Disclosure of Invention

The invention aims to provide a method for blocking a heat exchange tube, which has a wide application range and does not need to weld a sealing weld again.

In order to achieve the aim, the invention provides a method for plugging a heat exchange tube, which comprises the following steps:

processing an annular boss on the outer wall of the sealing plug in advance, and processing a first locking part on the outer wall of the pressing plug;

step surfaces which are in contact fit with the annular bosses are machined on the inner walls of the plugging parts of the two ends of the heat exchange tube so as to form step holes in the tube orifice of the heat exchange tube;

a second locking part matched and locked with the first locking part is machined at the large end of the stepped hole;

inserting the sealing plug into the heat exchange tube to enable the annular boss to be attached to the step surface;

inserting a compression plug into the heat exchange tube, and enabling the annular boss to compress the step surface through matching and locking of the first locking part and the second locking part;

and carrying out anti-loosening treatment on the compaction plug.

The first locking portion is an external thread formed on the outer wall of the compression plug, and the second locking portion is an internal thread formed on the large end of the stepped hole.

Wherein the length of the internal thread is less than the length of the large end of the stepped hole.

Wherein, the top of the compressing plug is provided with a driving position used for being matched with an installation tool.

The driving position is a mounting hole formed in the top of the compression plug, and the mounting hole is used for being connected with the inner angle wrench in a matched mode.

The cross section of the mounting hole is in a shape of a triangle, a quadrangle, a hexagon or an octagon.

The anti-loosening treatment is carried out on the compaction plug, specifically, the mechanical anti-loosening treatment is carried out on the compaction plug or the welding anti-loosening treatment is carried out on the compaction plug.

Wherein the compression plug is integrally formed with the sealing plug.

And a sealing layer is plated on the step surface.

Wherein, the step surface is a conical surface.

The invention has simple process flow and convenient operation, and the pipe orifice of the heat exchange pipe can be blocked by the sealing plug by processing the step surface which is used for being in interference fit with the annular boss of the sealing plug on the inner wall of the pipe orifice of the heat exchange pipe; meanwhile, the second locking part matched with the first locking part of the compression plug for locking is processed on the inner wall of the heat exchange tube, so that the compression plug can be utilized to abut against the sealing plug, the annular boss is locally deformed, and the sealing of the heat exchange tube can be realized. Therefore, the invention is not only suitable for the heat exchange tube in high temperature environment and with smaller inner diameter, greatly improves the application range, but also does not need to polish and remove the original sealing weld between the heat exchange tube and the tube plate, simplifies the process flow and effectively reduces the influence of high-temperature creep pressing force.

Drawings

FIG. 1 is a schematic view of a process of plugging a heat exchange tube in example 1 of the present invention;

fig. 2 is a schematic view of a process of plugging a heat exchange tube in example 2 of the present invention.

Reference numerals:

1. a heat exchange pipe; 1-1, step surface; 1-2, internal threads; 2. a sealing plug; 3. the plug is compressed.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, unless otherwise specified, the terms "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the system or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.