Technological method for tensioning stator core by half tensioner

Abstract

The invention relates to the field of steam turbine generators, and discloses a process method for tensioning a stator core by half of tensioners, aiming at the steam turbine generator with an old structure for many years, the thread length of a positioning rib of the stator core is designed to be relatively short and can only meet the use requirement of a positioning rib nut, while the tensioner in the existing new process is not suitable for the use of a positioning rib nut. In order to solve the problem that a stretcher is used when positioning ribs of an old structure are repaired on site, a half of positioning rib threads distributed at intervals are used for installing positioning rib nuts, and the other half of positioning rib threads are used for installing the stretcher. And when the stator core is tensioned by half of the tensioners, the other half of the positioning rib nuts are rotated and tightened, so that the purpose of tensioning the stator core on site is realized, and the problem that the stator core of a turbonator with an old structure is difficult to tension the stator core on site by using a new process is solved.

Description

Technical Field

[0001] The invention relates to the field of steam turbine generators, and in particular to a process method for tightening a stator core with a half-stretcher. Background Art

[0002] When the steam turbine generator is running on site, it is sometimes necessary to increase the tightness of the stator core on site due to various reasons.

[0003] The existing technology for improving the tightness of the stator core on site requires the use of a horizontal hydraulic press. A heavy and strong tool jig is installed at both ends of the stator core. The jigs at both ends and the center pull column of the horizontal hydraulic press are installed in the stator core chamber. Pressure is applied to the stator core through these tools and equipment, and then various wrenches are used to tighten the nuts of the positioning ribs. The entire operation is difficult and takes a long time. There is also a fatal problem that in order to tighten the stator core, all the stator windings must be removed first, which takes a long time and causes great losses.

[0004] With the development of technology, the tensioning technology used in the stator core now uses a stretcher. It is only necessary to fix multiple stretchers on the extended threads outside the nut of each positioning rib, and give all the stretchers a force at the same time, so that these stretchers stretch the threads of these positioning ribs at the same time, thereby generating reverse pressure to compress the stator core. In this way, the tightness of the stator core is improved. This technology can preserve the entire stator winding from damage, greatly reducing the workload and construction period of on-site repair of the stator core, minimizing losses and improving work efficiency.

[0005] In the production process of old-structure steam turbine generators produced in the early years, various wrenches were used to tighten the nuts of the locating ribs, and the tensioners used in the current new technology were not used. Therefore, the thread length of the locating ribs was only enough to meet the needs of the nuts, and there was no extended thread used by the tensioners.

[0006] In view of this, it is urgent to develop a process method that can improve the stator core tightness of old-structure steam turbine generators without dismantling the stator winding on site, so as to meet the needs of the current power industry life extension market. Summary of the invention

[0007] The purpose of the present invention is to provide a practical, convenient and practical process for tightening the stator core of a steam turbine generator on site. The technical solution of the present invention is:

[0008] S1. When the stator core needs to be tightened during on-site repair of an old steam turbine generator, if the thread of the positioning rib is too short to install nuts and tensioners at the same time, half of the threads of the positioning ribs with intervals should be installed with nuts, and the other half of the threads of the positioning ribs should not be installed with nuts but only with tensioners;

[0009] S2. Use half of the tensioner to tighten the positioning rib, press the stator core through the stator pressing ring, tighten half of the nuts assembled on the positioning rib threads, loosen and move the tensioner forward on the positioning rib threads according to the stroke of the tensioner, tighten the positioning rib with the tensioner again, press the stator core through the stator pressing ring, tighten half of the nuts assembled on the positioning rib threads, and repeat the operation until the tightness of the stator core meets the requirements;

[0010] S3. Remove the tensioner and replace it with nuts. Tighten half of the nuts installed for the second time according to the specified torque to achieve the purpose of all nuts pressing the stator core together with the same pulling force.

[0011] The technical effects of the present invention are:

[0012] 1. The present invention can make the stator core of the steam turbine generator with the old structure positioning ribs whose thread length of the positioning ribs cannot be used by the tensioner, realize the operation of tightening the stator core on site, and make the tightness of the stator core meet the requirements.

[0013] 2. Compared with the original process method, the present invention can achieve the tightening of the stator core without removing any parts of the stator winding, making the entire repair process simple and easy to operate, greatly improving work efficiency and greatly shortening the repair period.

[0014] 3. The present invention tightens the stator core on site, thus saving a number of bulky tools in the original technical method and being able to quickly respond to the need for tightening the stator core on site. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Front view of the stator core being tightened by half of the tensioners.

[0016] Figure 2 Side view of the stator core being tightened by half of the tensioners.

[0017] Figure 3 Assembly drawing of the stretcher.

[0018] Figure 4 Assembly diagram for the nut.

[0019] Explanation of the markings in the attached drawings: 1- stator core; 2- positioning rib; 3- thread; 4- nut; 5- stator pressure ring; 6- tensioner. DETAILED DESCRIPTION

[0020] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0021] The process of tightening the stator core with half of the tensioners. Taking the on-site repair of a steam turbine generator as an example, the process implementation process is as follows:

[0022] 1. According to Figure 1 , the stator core 1 and the stator pressing ring 5 have been assembled in place on site, nuts 4 are assembled on half of the positioning ribs 2 threads 3 at intervals, and tensioners 6 are assembled on the other half of the positioning ribs 2 threads 3;

[0023] 2. According to Figure 2 and Figure 3 , after applying oil pressure to the tensioner 6, the stator core 1 is tightened by pressing the stator pressing ring 5;

[0024] 3. According to Figure 2 and Figure 4 At this time, there will be a gap between the stator pressing ring 5 and the nut 4, tighten the nut 4;

[0025] 4. According to Figure 2 and Figure 3 , reduce the oil pressure of the tensioner 6 to zero, rotate the tensioner 6 on the thread 3 of the positioning rib 2 toward the stator pressing ring 5, and apply oil pressure again to tighten the stator core 1 by pressing the stator pressing ring 5;

[0026] 5. According to Figure 2 and Figure 4 , rotate and tighten the nut 4 again to eliminate the gap between the stator pressing ring 5 and the nut 4;

[0027] 6. Repeat the operation until the tensile force meets the requirements and there is no gap between the stator pressing ring 5 and the nut 4;

[0028] 7. Remove the tensioner 6 on the thread 3 of half of the positioning rib 2, install the nut 4, and tighten the second installed nut 4 according to the specified torque.

[0029] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, it should be clear to those skilled in the art that the technical solutions described in the above embodiments may be modified, or some or all of the technical features therein may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A process for tightening a stator core with half a tensioner, characterized by comprising the following steps: S1. When the stator core (1) of an old steam turbine generator needs to be tightened during on-site repair, if the thread (3) of the positioning rib (2) is too short to install the nut (4) and the tensioner (6) at the same time, half of the thread (3) of the positioning rib (2) distributed at intervals are installed with the nut (4), and the other half of the thread (3) of the positioning rib (2) is not installed with the nut (4) but only with the tensioner (6); S2. Use half of the tensioner (6) to tighten the positioning rib (2), press the stator core (1) through the stator pressing ring (5), tighten half of the nuts (4) assembled on the thread of the positioning rib (2), loosen and move the tensioner (6) forward on the thread (3) of the positioning rib (2) according to the stroke of the tensioner (6), tighten the positioning rib (2) with the tensioner (6) again, press the stator core (1) through the stator pressing ring (5), tighten half of the nuts (4) assembled on the thread of the positioning rib (2), and repeat the operation until the tightness of the stator core (1) meets the requirements; S3. Remove the tensioner (6) and replace it with the nut (4). Tighten the half of the nuts (4) installed for the second time according to the specified torque. All the nuts press the stator core (1) together with the same tension.

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