A method for treating steam leakage of a steam turbine shaft seal

Abstract

The application discloses a steam turbine shaft seal body steam leakage processing method and belongs to the technical field of steam turbine equipment. The processing method comprises the following steps: S1, measuring the axial gap between the steam cylinder groove and the shaft seal body provided with an adjusting ring, and indirectly measuring the flatness of the outermost and innermost positions in the depth direction of the steam cylinder groove; S2, grinding the steam cylinder groove plane to the outer plane of the adjusting ring of the shaft seal body by using the original adjusting ring of the shaft seal body as a grinding reference, so that the whole-circle width of the steam cylinder groove is uniform; S3, grinding the width of the inner vertical surface of the measured steam cylinder groove, so as to determine the axial gap of the shaft seal body provided with the adjusting ring, and adding a gasket between the adjusting ring and the shaft seal body according to the gap data, so as to ensure that the inner vertical surface of the steam cylinder groove is attached to the outer vertical surface of the adjusting ring of the shaft seal body; and S4, adding an external seal between the shaft seal body and the external steam cylinder body. The application can greatly reduce the steam leakage processing cost and processing time of the shaft seal body.

Description

Technical Field

[0001] This invention relates to the field of steam turbine equipment technology, and more specifically, to a method for dealing with steam leakage in a steam turbine shaft seal. Background Technology

[0002] Steam leakage from shaft seals is common during turbine overhauls and modifications, especially when cylinder block deformation or cylinder boring is involved. If the inner diameter of the shaft seal deviates, the clearance between the cylinder block and the shaft seal increases, causing steam leakage from the shaft seal, resulting in water in the oil and affecting the safe operation of the unit.

[0003] In the past, when steam leakage occurred in the shaft seal, the traditional methods were to either perform secondary boring or modify the shaft seal. Although these two methods could solve the problem of steam leakage, the construction period was long. The boring cycle was generally more than 7 days, while the processing cycle for modifying the shaft seal was about 30 days.

[0004] Obviously, the construction period of the above two methods is relatively long and the corresponding cost is also relatively high. Therefore, we propose a method for dealing with steam leakage in the turbine shaft seal to solve the above problems. Summary of the Invention

[0005] In view of the above-mentioned problems in the existing technology, the purpose of the present invention is to provide a method for dealing with steam leakage in the turbine shaft seal.

[0006] To solve the above problems, the technical solution adopted by the present invention is as follows: A method for handling steam leakage in a turbine shaft seal, comprising a shaft seal equipped with an adjusting ring, and the following steps: S1. Measure the axial clearance between the cylinder groove and the shaft seal body, and indirectly measure the flatness of the outermost and innermost positions of the cylinder groove in the depth direction; S2. Using the adjusting ring as a grinding reference, grind the outer plane of the cylinder groove until the outer plane of the adjusting ring fits into the inner plane of the cylinder groove, so that the width of the cylinder groove is uniform throughout the entire circle. S3. Measure the width of the inner vertical surface of the cylinder groove after grinding, determine the axial clearance between the inner vertical surface of the cylinder groove and the shaft seal body with the adjusting ring, and add shims between the adjusting ring and the shaft seal body according to the clearance between the inner vertical surface of the cylinder groove and the outer vertical surface of the adjusting ring so that the inner vertical surface of the cylinder groove and the outer vertical surface of the adjusting ring fit together. S4. A pressure ring is installed between the shaft seal body and the cylinder body for sealing, and asbestos packing is placed between the pressure ring and the adjusting ring. The external flexible seal of the shaft seal body is achieved by natural compression between the cylinder groove and the shaft seal body.

[0007] Furthermore, during the measurement process in step S1, the axial clearance between the shaft seal body and the cylinder groove at various points along the circumference is measured.

[0008] Furthermore, in the process of determining the axial clearance in step S3, the axial clearance between the shaft seal body equipped with the adjusting ring and the cylinder groove at various points along the circumference is measured.

[0009] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention can perform grinding and inspection on the expansion gap between the cylinder and the shaft seal body by adjusting the ring, achieving initial axial sealing after the cylinder expands at high temperature. Then, gaskets are used to compensate for the seal between the adjusting ring and the shaft seal body. Finally, graphite packing is used in conjunction with the pressure ring to fix it, achieving secondary filling and sealing of the cylinder axially. Compared with the traditional method of directly processing and modifying the shaft seal body or cylinder, the construction cycle is obviously shorter and the cost is lower. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the structure corresponding to the air leakage treatment process of the shaft seal body of the present invention.

[0011] In the diagram: 1. Shaft seal body; 2. Groove; 3. Adjusting ring; 4. Shim; 5. Graphite packing; 6. Pressure ring; 7. Cylinder. Detailed Implementation

[0012] The present invention will be further described below with reference to specific embodiments.

[0013] like Figure 1 As shown, in this embodiment, the leak handling step is specifically as follows: First, the flatness of the outer diameter of the shaft seal 1 and the outermost and innermost positions of the groove 2 of the cylinder 7 in the depth direction are measured to determine the deviation value of the cylinder 7 relative to the shaft seal 1 in the axial direction after high-temperature expansion. Figure 1 The deviation of dimension b relative to dimension c.

[0014] Based on the deviation value, an adjusting ring 3 that is adapted to the outer diameter of the shaft seal 1 is sleeved on the shaft seal 1, and the outer plane of the adjusting ring 3 is used to perform contact grinding inspection on the outer plane of the cylinder 7 groove 2. The outer plane of the cylinder 7 groove 2 is ground synchronously until the outer plane of the adjusting ring 3 is flush with the outer plane of the cylinder 7 groove 2.

[0015] The gap between the inner surface of the groove 2 of cylinder 7 and the outer surface of the adjusting ring 3 is measured a second time. A shim 4 is added between the inner surface of the adjusting ring 3 and the outer surface of the shaft seal 1 to fit the inner surface of the groove 2 of cylinder 7 and the outer surface of the adjusting ring 3. The specific steps for determining the thickness of the shim 4 are as follows: In both the first and second measurements, considering that the high-temperature expansion and deformation of cylinder 7 is an integral deformation, there are deviation gaps in various parts of the circumference. Therefore, the measurement positions are increased, and corresponding measurements are performed on the left, upper and lower sides of the circumference to ensure comprehensive data coverage.

[0016]

[0017] Based on the measurement data in the table above, it can be seen that ab and ac are in opposite directions, and the thickness of shim 4 is the sum of the absolute values ​​of the two, which can be determined to be 1.4mm. After shim 4 is filled, it can provide sealing compensation between shaft seal 1 and cylinder groove 2, and the inner surface of cylinder 7 groove 2 and the outer surface of adjusting ring 3 can be fitted again to ensure that no gap remains.

[0018] When cylinder 7 is reinstalled, if Figure 1 As shown, a pressure ring 6 adapted to the outer diameter of the cylinder 7 can be used to axially seal the side of the adjusting ring 3 that is away from the groove 2 of the cylinder 7, and an annular graphite packing 5 can be filled between the pressure ring 6 and the adjusting ring 3; the graphite packing 5 can seal the shaft seal 1 a second time to ensure that the leakage of the shaft seal 1 is eliminated.

[0019] Repeat the above steps to address steam leakage in the upper and lower halves of the shaft seal 1 in the turbine. (Details omitted here.) Similarly, when reinstalling the upper and lower halves of the shaft seal 1, sealant can be applied inside the groove 2 of the cylinder 7 to enhance overall sealing performance. After the secondary fitting inspection is passed, axial expansion clearance grinding is performed during rotor shaft alignment measurement, and acceptance is conducted according to axial clearance standards.

[0020] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A method for treating steam leakage in a steam turbine shaft seal, characterized in that, The processing steps for the shaft seal body, including the one with the adjusting ring, are as follows: S1. Measure the axial clearance between the cylinder groove and the shaft seal body, and indirectly measure the flatness of the outermost and innermost positions of the cylinder groove in the depth direction; S2. Using the adjusting ring as a grinding reference, grind the outer plane of the cylinder groove until the outer plane of the adjusting ring fits into the inner plane of the cylinder groove, so that the width of the cylinder groove is uniform throughout the entire circle. S3. Measure the width of the inner vertical surface of the cylinder groove after grinding, determine the axial clearance between the inner vertical surface of the cylinder groove and the shaft seal body with the adjusting ring, and add shims between the adjusting ring and the shaft seal body according to the clearance between the inner vertical surface of the cylinder groove and the outer vertical surface of the adjusting ring so that the inner vertical surface of the cylinder groove and the outer vertical surface of the adjusting ring fit together. S4. A pressure ring is installed between the shaft seal body and the cylinder body for sealing, and asbestos packing is placed between the pressure ring and the adjusting ring. The external flexible seal of the shaft seal body is achieved by natural compression between the cylinder groove and the shaft seal body.

2. The method for treating steam leakage in a turbine shaft seal body according to claim 1, characterized in that: During the measurement process in step S1, the axial clearance between the shaft seal body and the cylinder groove at various points along the circumference is measured.

3. The method for treating steam leakage in a turbine shaft seal according to claim 1, characterized in that: In step S3, during the determination of axial clearance, the axial clearance between the shaft seal body equipped with the adjusting ring and the cylinder groove is measured at various points along the circumference.

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