Steam seal gap measuring tool

Abstract

The utility model discloses a steam seal clearance measuring tool, which solves the problem that the existing steam seal clearance test of a steam turbine is time-consuming and labor-consuming. Comprising a cylinder inner partition plate (1), a steam sealing block embedded T-shaped groove (2) is formed in the cylinder inner partition plate (1), an I-shaped steam sealing block (3) is movably arranged in the steam sealing block embedded T-shaped groove (2), a left side gap (9) is formed between the outer side face of the left side of the I-shaped steam sealing block (3) and the inner side face of the cylinder inner partition plate (1), and a right side gap (9) is formed between the outer side face of the right side of the I-shaped steam sealing block (3) and the inner side face of the cylinder inner partition plate (1). A right side gap (10) is formed between the outer side face of the right side of the I-shaped steam seal block (3) and the inner side face of the cylinder inner partition plate (1), a left wedge block (11) is inserted into the left side gap, a right wedge block (12) is movably inserted into the right side gap (10), and the structure of the left wedge block is completely the same as that of the right wedge block; the number of times of repeated testing and detection of the steam seal gap in the later period is greatly reduced, and the working efficiency of steam gap adjustment is improved.

Description

Technical Field

[0001] The present invention relates to a steam turbine of a thermal power plant, in particular to a steam seal gap measuring tool and a steam seal gap measuring and adjusting method used when assembling a steam turbine unit of a thermal power plant. Background Art

[0002] The turbine body is mainly composed of four parts: rotor, stator, bearings and bearing box, and turning device; the rotor is the rotating part in the turbine flow, and is composed of main components such as main shaft, blades, couplings, etc. The turbine rotors, as well as the turbine rotor and generator rotor are connected by couplings to transmit torque and axial force; the stator is the stationary part in the turbine flow and the turbine casing, and is composed of cylinder, partition and partition sleeve, steam inlet part, exhaust part, steam seal and shaft seal, etc. Among them, the cylinder is the outer casing of the steam turbine, and is equipped with nozzle chamber, nozzle, partition, partition sleeve and steam seal and other components inside, and regulating steam valve and steam inlet, exhaust and oil inlet and return pipes outside; the function of the steam seal is to separate the flow part of the steam turbine from the atmosphere, forming a closed steam chamber to ensure that the steam completes its energy conversion process in the turbine. When the steam turbine is running, the rotor rotates at high speed and the stator is fixed. Therefore, a certain distance must be maintained between the rotor and the stator. When steam flows through the turbine's poles, its pressure and temperature gradually decrease, creating a pressure differential across the partitions. While most of the steam flows through the guide vanes and moving blades to produce work, a small portion flows through the gaps without producing work, resulting in a loss that reduces turbine efficiency. The rotor shaft must also pass through the cylinder and be supported on bearings, where clearance is also required. At both ends of the high- and medium-pressure cylinders, the steam pressure within the cylinders is greater than atmospheric pressure, causing steam to leak out, reducing efficiency and causing some condensate loss. At both ends of the low-pressure cylinder, because the steam pressure within the cylinders is lower than the external atmospheric pressure, air will leak into the cylinder through the gap where the main shaft passes through the cylinder. To reduce steam leakage through the aforementioned gaps (or air leakage from the outside) while ensuring normal and safe operation of the turbine, various steam seals are installed. These seals can be divided into three categories: flow seals, partition seals, and front and rear cylinder seals.

[0003] The steam seal is a mechanism installed between the dynamic and static parts of the steam turbine to reduce or prevent steam leakage and air leakage into the vacuum side. Taking a 300MW unit as an example, the equipment layout of the steam turbine unit is, from the head side, the front box, high and medium pressure cylinders, the middle box, the low pressure cylinder, and the low pressure rear box. Each bearing box and the low pressure cylinder are located on the foundation plate. The extended cat claws of the high and medium pressure cylinders are placed on the bearing box respectively. The rotor is supported by the bearing shell located on the bearing box. The bearing shell is plated with tungsten gold (about 3 mm thick) to protect the rotor and steam seal from damage and wear in the event of a turbine accident. There are multi-stage partitions in the cylinder, and end steam seals are installed on the front and rear sides of the cylinder. The partitions and end steam seals are divided into upper and lower halves. The upper and lower half steam seals are composed of 3 steam seal blocks, namely the left, right and bottom steam seal blocks. A steam turbine unit has nearly 60 circles of partition steam seals and end steam seals, a total of There are 360 ​​steam seal blocks in total, which are clamped in the steam seal body groove by springs, and the steam seal body groove is set on the cylinder; each level of partition steam seal and end steam seal are arranged with high and low teeth, which mesh with the low and high teeth of the rotor to form a steam seal gap, which is generally required to be 0.25±0.10 mm; in the assembly of the steam turbine, whether the steam seal gap is adjusted accurately directly affects the thermal efficiency of the steam turbine; steam seal gap adjustment is one of the key and difficult points in the installation and maintenance of the steam turbine; the steam seal block is clamped in the steam seal body groove by springs and is elastically fixed. The steam seal block can retreat, and the retreat gap is generally 3-4 mm; before measuring the steam seal gap, the steam seal block must be evenly lifted and fixed, and it cannot retreat and rebound, so that the steam seal gap can be accurately measured; that is, a wooden wedge must be embedded in the retreat space of the steam seal block in the steam seal body groove to lift and fix the steam seal block, so that the steam seal gap can be measured.

[0004] Adjusting the steam seal gap is one of the important difficulties in the installation and maintenance of steam turbines. Before measuring the steam seal gap, the spring of the steam seal block needs to be removed and then lifted up with wooden wedges or other process tools, that is, the steam seal block needs to be fixed and lifted up evenly, so that the steam seal gap can be accurately measured and the steam seal gap can be judged based on the measurement data. Otherwise, the unqualified steam seal needs to be scraped and adjusted, and the measurement and adjustment are repeated until it is qualified. There are many steam seal blocks and the space is small. Therefore, evenly fixing and lifting the steam seal block is an important construction process with the largest workload and the most difficult technology in the process of measuring and adjusting the steam seal gap. The traditional method of testing and adjusting the steam seal gap has the following problems: (1) The thickness deviation of the wooden wedges is poor; (2) In the process of embedding the wooden wedges in the retreat space of the steam seal block, the steam seal block is prone to unevenness; (3) A large number of wooden wedges need to be made each time the test is repeated, resulting in increased labor and material costs; (4) Repeated testing has the disadvantages of being time-consuming and labor-intensive. Summary of the Invention

[0005] The invention provides a steam seal gap measuring tool, which solves the technical problem of time-consuming and labor-intensive existing steam turbine steam seal gap testing.

[0006] The present invention solves the above technical problems through the following technical solutions:

[0007] A steam seal gap measuring tool comprises a cylinder inner partition plate, a steam seal block is provided on the cylinder inner partition plate and embedded in a T-shaped groove, an I-shaped steam seal block is movably provided in the steam seal block embedded in the T-shaped groove, a stator steam seal low teeth and a stator steam seal high teeth are respectively provided on the inner side surface of the I-shaped steam seal block, a rotor is provided on the inner side of the I-shaped steam seal block, a rotor steam seal high teeth and a rotor steam seal low teeth are respectively provided on the rotor, the stator steam seal low teeth and the rotor steam seal high teeth are correspondingly meshed, and the stator steam seal high teeth and the rotor steam seal low teeth are correspondingly meshed, a left gap is formed between the left outer side surface of the I-shaped steam seal block and the inner side surface of the cylinder inner partition plate, a right gap is formed between the right outer side surface of the I-shaped steam seal block and the inner side surface of the cylinder inner partition plate, a left wedge block is inserted in the left gap, and a right wedge block is movably inserted in the right gap, and the structure of the left wedge block is exactly the same as that of the right wedge block.

[0008] After the left wedge block is inserted into the left gap and the right wedge block is movably inserted into the right gap, the I-shaped steam seal block is fixed and cannot retreat to the T-shaped groove where the steam seal block is embedded. The spacing T1 between the stator steam seal high teeth set on the left side of the inner side surface of the I-shaped steam seal block and the corresponding meshing rotor steam seal low teeth is equal to the spacing T2 between the steam seal high teeth set on the right side of the inner side surface of the I-shaped steam seal block and the corresponding meshing rotor steam seal low teeth.

[0009] The spacing T1 between the high teeth of the stator steam seal arranged on the left side of the inner side of the I-shaped steam seal block and the corresponding meshing low teeth of the rotor steam seal is 0.15 mm-0.35 mm; the width of the left gap is 3-4 mm.

[0010] The left wedge block is in the shape of a right triangle. Comb teeth are arranged at equal intervals on the hypotenuse of the left wedge block, and a scale ruler indicating the height of each comb tooth is arranged on the front side elevation of the left wedge block.

[0011] A method for adjusting a steam seal clearance, characterized by comprising the following steps:

[0012] The first step is to place the bearing box and lower cylinder of the steam turbine unit on the workbench;

[0013] The second step is to check whether the inner diaphragms (sleeves) and steam seals (sleeves) of the upper and lower cylinders of the steam turbine are intact. If they are intact, remove the fixing springs of the I-shaped steam seal blocks in the upper and lower cylinders, and remove each I-shaped steam seal block from the corresponding T-shaped groove of the steam seal block. Check whether the I-shaped steam seal block has oil stains and whether the edges of the steam seal teeth are flat and free of curling.

[0014] Step 3: Install the I-shaped steam seal block and the fixed spring back into the steam seal block and embed it into the T-shaped groove;

[0015] Step 4: Insert the left wedge-shaped block of the right triangle into the left gap, and insert the right wedge-shaped block of the right triangle into the right gap, so that the I-shaped steam seal block protrudes outward and the I-shaped steam seal block cannot retreat into the T-shaped groove of the steam seal block;

[0016] Step 5. Determine the comb teeth on the left wedge block that are in contact with the left outer side of the I-shaped steam seal block, and read the reading of the comb teeth on the scale ruler. The reading is the width of the left gap; determine the comb teeth on the right wedge block that are in contact with the right outer side of the I-shaped steam seal block, and read the reading of the comb teeth on the scale ruler. The reading is the width of the right gap;

[0017] Step 6. Compare the left gap width obtained in step 5 with the right gap width. If the two readings are not equal, remove the I-shaped steam seal block from the T-shaped groove and repair it. Then, repeat steps 3 to 6 until the left gap width is equal to the right gap width and the left gap is 3 mm to 4 mm.

[0018] Step 7. Apply a layer of adhesive tape on the steam seal surface of the lower teeth of each stator steam seal of the upper cylinder and the lower cylinder, as well as on the steam seal surface of the higher teeth of the stator steam seal. The thickness of the adhesive tape is 0.25 mm.

[0019] Step 8: Apply red lead powder on the steam cover of the rotor steam seal high teeth and the steam cover of the rotor steam seal low teeth of the rotor, with a width of 100 mm;

[0020] Step 9: Assemble the rotor of the steam turbine unit into the bearing housing of the steam turbine unit, and buckle the upper cylinder and the lower cylinder together;

[0021] Step 10. Press the turbine's rotation wheel to move the rotor 360 degrees.

[0022] Step 11. Disassemble the upper cylinder and lift out the rotor, and check the condition of the tape on each steam seal: If there is light red lead powder on the tape, it means that the steam seal tooth and the rotor are slightly in contact, and the steam seal gap of the steam seal tooth is qualified; if there is dark red lead powder on the tape or the tape is cut, it means that the steam seal gap of the steam seal tooth is too small, and the position of the corresponding I-shaped steam seal block needs to be adjusted; if there is no trace of red lead powder on the tape, it means that the steam seal gap of the steam seal tooth is too large, and the position of the corresponding I-shaped steam seal block needs to be adjusted.

[0023] The tooling of the present invention is simple and easy to operate, and can evenly fix and lift the steam seal block of the steam turbine in the steam seal block groove to obtain accurate steam seal clearance of the steam turbine; through the tooling of the right-angled triangular wedge block with a height scale, the purpose of evenly lifting the steam seal block is achieved, and the gap width readings on both sides after the steam seal block is completely lifted can be read at a glance, which is convenient for comparison with the design value, and unqualified steam seal blocks can be repaired in time before turbine assembly, which greatly reduces the number of times that the steam seal clearance needs to be repeatedly tested and inspected in the later stage, and improves the working efficiency of the steam gap adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0025] The present invention is described in detail below in conjunction with embodiments:

[0026] A steam seal clearance measuring tool comprises a cylinder inner partition plate 1, a steam seal block embedded in a T-shaped groove 2 is provided on the cylinder inner partition plate 1, an I-shaped steam seal block 3 is movably provided in the steam seal block embedded in the T-shaped groove 2, an outer T-shaped end of the I-shaped steam seal block 3 is movably embedded in the steam seal block embedded in the T-shaped groove 2, a spring is provided between the outer T-shaped end and the steam seal block embedded in the T-shaped groove 2, the spring floats the I-shaped steam seal block 3 on the inner side of the cylinder inner partition plate 1; a stator steam seal low tooth 4 and a stator steam seal high tooth 5 are respectively provided on the inner side surface of the I-shaped steam seal block 3, a turbine unit rotor 6 is provided on the inner side of the I-shaped steam seal block 3, a rotor steam seal high tooth 7 and a rotor steam seal low tooth 8 are respectively provided on the rotor 6, the stator steam seal low tooth 4 and the rotor steam seal high tooth 7 are correspondingly meshed. The high teeth 5 of the stator steam seal and the low teeth 8 of the rotor steam seal are arranged in correspondence with each other, thereby realizing the steam sealing of the gap in the cylinder. A left gap 9 is formed between the left outer side surface of the I-shaped steam seal block 3 and the inner side surface of the partition plate 1 in the cylinder, and a right gap 10 is formed between the right outer side surface of the I-shaped steam seal block 3 and the inner side surface of the partition plate 1 in the cylinder. The left gap 9 and the right gap 10 are the gaps for the I-shaped steam seal block 3 to retreat into the T-shaped groove 2 when the steam seal block is embedded; a left wedge block 11 is inserted into the left gap 9, and a right wedge block 12 is movably inserted into the right gap 10, and the structure of the left wedge block 11 is exactly the same as that of the right wedge block 12; when the two wedge blocks are tightly inserted into the gaps on both sides, the left gap 9 and the right gap 10 are the maximum gaps that can be explored inward by the I-shaped steam seal block 3.

[0027] After the left wedge block 11 is inserted into the left gap 9 and the right wedge block 12 is movably inserted into the right gap 10, the I-shaped steam seal block 3 is fixed and cannot retreat to the T-shaped groove 2 to embed the steam seal block. The spacing T1 between the stator steam seal high teeth 5 set on the left side of the inner side surface of the I-shaped steam seal block 3 and the corresponding meshing rotor steam seal low teeth 8 is equal to the spacing T2 between the steam seal high teeth 5 set on the right side of the inner side surface of the I-shaped steam seal block 3 and the corresponding meshing rotor steam seal low teeth 8; T1 equals T2, which means that both sides of the I-shaped steam seal block 3 protrude evenly and are qualified steam seal blocks. Otherwise, they need to be scraped and repaired.

[0028] The spacing T1 between the stator steam seal high teeth 5 and the corresponding meshing rotor steam seal low teeth 8 set on the left side of the inner surface of the I-shaped steam seal block 3 is 0.15 mm-0.35 mm; the width of the left side gap 9 is 3-4 mm to ensure that after the 3 mm tungsten gold coating plated on the bearing shell is worn off, the steam seal teeth on the stator and the steam seal teeth on the rotor will not be scratched.

[0029] The left wedge block 11 is in the shape of a right triangle. Comb teeth are arranged at equal intervals on the hypotenuse of the left wedge block 11, and a scale 13 for the height of each comb tooth is provided on the front side elevation of the left wedge block 11. The scale 13 indicates the vertical distance height of the corresponding comb teeth on the wedge block, that is, the width of the left gap 9 after the I-shaped steam seal block 3 is completely extended out of the steam seal block and embedded in the T-shaped groove 2. Based on these two readings, it can be determined whether the I-shaped steam seal block 3 needs to be repaired.

[0030] A method for adjusting a steam seal clearance, characterized by comprising the following steps:

[0031] The first step is to place the bearing box and lower cylinder of the steam turbine unit on the workbench;

[0032] Step 2: Check whether the inner diaphragms (sleeves) and steam seals (sleeves) of the upper and lower cylinders of the steam turbine are intact. If so, remove the fixing springs of the I-shaped steam seal blocks 3 in the upper and lower cylinders, and remove each I-shaped steam seal block 3 from the corresponding T-shaped groove 2. Check whether the I-shaped steam seal block 3 is greasy, and whether the edges of the steam seal teeth are flat and free of curling. If there is no greasy stain and the edges of the steam seal teeth are intact, proceed to the next step.

[0033] Step 3: Install the I-shaped steam seal block 3 and the fixing spring back into the steam seal block and embed it into the T-shaped groove 2;

[0034] Step 4: Insert the right triangle-shaped left wedge block 11 into the left gap 9 and the right triangle-shaped right wedge block 12 into the right gap 10, so that the I-shaped steam seal block 3 protrudes outward and cannot retreat into the T-shaped groove 2 where the steam seal block is embedded, completely simulating the normal working state of the I-shaped steam seal block 3 in the cylinder;

[0035] Step 5. Determine the comb teeth on the left wedge block 11 that are in contact with the left outer side of the I-shaped steam seal block 3, and read the reading of the comb teeth on the scale 13. The reading is the width of the left gap 9; determine the comb teeth on the right wedge block 12 that are in contact with the right outer side of the I-shaped steam seal block 3, and read the reading of the comb teeth on the scale 13. The reading is the width of the right gap 10. Determine whether the two widths are consistent and whether they are between 3-4 mm;

[0036] Step 6. Compare the width of the left gap 9 obtained in step 5 with the width of the right gap 10. If the two readings are not equal, remove the I-shaped steam seal block 3 from the steam seal block embedded in the T-shaped groove 2 and repair it again. Then, repeat the above steps from step 3 to step 6 until the width of the left gap 9 is equal to the width of the right gap 10, and the left gap 9 is 3 mm to 4 mm.

[0037] The above steps realize the preliminary adjustment of the steam seal gap, and basically realize the preliminary adjustment of the steam seal gap in place. Then, the following steps of assembling the upper cylinder, rotor and lower cylinder are carried out, which greatly saves the working time of steam gap adjustment.

[0038] Step 7: Apply a layer of adhesive tape on the steam sealing surface of the low teeth 4 of each stator seal of the upper cylinder and the lower cylinder, as well as on the steam sealing surface of the high teeth 5 of the stator seal. The thickness of the adhesive tape is 0.25 mm.

[0039] Step 8: Apply red lead powder on the steam sealing surface of the rotor steam seal high teeth 7 and the steam sealing surface of the rotor steam seal low teeth 8 of the rotor, with a width of 100 mm;

[0040] Step 9: Assemble the rotor of the steam turbine unit into the bearing housing of the steam turbine unit, and buckle the upper cylinder and the lower cylinder together;

[0041] Step 10. Press the turbine's rotation wheel to move the rotor 360 degrees.

[0042] Step 11. Disassemble the upper cylinder and lift out the rotor, and check the tape on each steam seal: If there is light red lead on the tape, it means that the steam seal tooth and the rotor are slightly in contact, and the steam seal gap of the steam seal tooth is qualified; if there is dark red lead on the tape or the tape is cut, it means that the steam seal gap of the steam seal tooth is too small, and the position of the corresponding I-shaped steam seal block 3 needs to be adjusted; if there is no trace of red lead on the tape, it means that the steam seal gap of the steam seal tooth is too large, and the position of the corresponding I-shaped steam seal block 3 needs to be adjusted;

[0043] The unqualified steam seal gaps detected in the above steps are very limited, accounting for a limited number of hundreds of steam seal gaps. It is only necessary to repair the I-shaped steam seal blocks 3 corresponding to these limited steam seal gaps.

Claims

1. A steam seal gap measuring tool, comprising a cylinder inner partition (1), a steam seal block embedded in a T-shaped groove (2) is provided on the cylinder inner partition (1), an I-shaped steam seal block (3) is movably provided in the steam seal block embedded in the T-shaped groove (2), a stator steam seal low tooth (4) and a stator steam seal high tooth (5) are respectively provided on the inner side surface of the I-shaped steam seal block (3), a rotor (6) is provided on the inner side of the I-shaped steam seal block (3), a rotor steam seal high tooth (7) and a rotor steam seal low tooth (8) are respectively provided on the rotor (6), the stator steam seal low tooth (4) and the rotor steam seal high tooth (7) are correspondingly meshed and arranged, and the stator steam seal high tooth (5) and the rotor steam seal low tooth (8) are correspondingly meshed and arranged, characterized in that: A left gap (9) is formed between the left outer side surface of the I-shaped steam seal block (3) and the inner side surface of the cylinder inner partition (1), and a right gap (10) is formed between the right outer side surface of the I-shaped steam seal block (3) and the inner side surface of the cylinder inner partition (1). A left wedge-shaped block (11) is inserted into the left gap (9), and a right wedge-shaped block (12) is movably inserted into the right gap (10). The structure of the left wedge-shaped block (11) is exactly the same as that of the right wedge-shaped block (12).

2. The steam seal gap measuring tool according to claim 1, characterized in that: After the left wedge block (11) is inserted into the left gap (9) and the right wedge block (12) is movably inserted into the right gap (10), the I-shaped steam seal block (3) is fixed and cannot be retracted into the T-shaped groove (2) to be embedded in the steam seal block. The spacing T1 between the stator steam seal high teeth (5) provided on the left side of the inner side surface of the I-shaped steam seal block (3) and the corresponding meshing rotor steam seal low teeth (8) is equal to the spacing T2 between the steam seal high teeth (5) provided on the right side of the inner side surface of the I-shaped steam seal block (3) and the corresponding meshing rotor steam seal low teeth (8).

3. The steam seal gap measuring tool according to claim 2, characterized in that: The spacing T1 between the stator steam seal high teeth (5) and the corresponding meshing rotor steam seal low teeth (8) provided on the left side of the inner side surface of the I-shaped steam seal block (3) is 0.15 mm to 0.35 mm; the width of the left gap (9) is 3 to 4 mm.

4. A steam seal gap measuring tool according to claim 1, 2 or 3, characterized in that: The left wedge-shaped block (11) is in the shape of a right triangle, and comb teeth are arranged at equal intervals on the hypotenuse of the left wedge-shaped block (11), and a scale (13) indicating the height of each comb tooth is arranged on the front side elevation of the left wedge-shaped block (11).

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