Method for measuring axial clearance of thrust bearing of steam turbine

Abstract

The invention relates to the field of steam turbine maintenance, in particular to a method for measuring the axial clearance of a thrust bearing of a steam turbine. The method comprises the following steps of: marking four measuring points at horizontal positions of a thrust bearing shell in sequence, and setting one measuring point on a second pair wheel; a laser tracker and a target ball are used for positioning the horizontal positions of the front and rear shells and the coordinates of marking points of the second pair wheel; then the shell is pushed to move towards the adjusting end until the second pair wheel moves, and at the moment, the laser tracker and the target ball are used for positioning the coordinates of the five measuring points again; the shell is pushed to move towards the electric end until the second pair wheel moves, and at the moment, the laser tracker and the target ball are used again for positioning the coordinates of the five measuring points; and after data collection, a thrust clearance result is automatically calculated by utilizing displacement of two measurement points. The axial clearance of the thrust bearing can be measured and calculated without erecting a dial indicator, the operation is simple and convenient, and the measurement result is accurate.

Description

Technical Field

[0001] The present invention relates to the field of steam turbine maintenance, and particularly to a method for measuring the axial clearance of a steam turbine thrust bearing. Background Art

[0002] The thrust bearing is a very important component on the steam turbine shafting. Its function is to bear the axial thrust of the rotor during the normal operation of the steam turbine and determine and maintain the axial relative position between the steam turbine rotor and the cylinder. The main methods for measuring the thrust bearing clearance in domestic nuclear power plants are as follows:

[0003] Install five dial indicators on the left and right sides of the thrust bearing housing and on the rotor coupling. Record the initial readings of the dial indicators. Select a special jackscrew or jack to move the thrust bearing housing towards the adjustment end at the position of the left and right wedges until the readings of the dial indicators on the rotor coupling change, then stop moving and record the readings of the dial indicators. Then move the housing towards the generator end until the readings of the dial indicators on the rotor shoulder change, then stop moving and record the dial indicator data. Calculate the thrust clearance value according to the following table.

[0004]

[0005] There are the following problems in measuring the thrust clearance value using the above method:

[0006] 1. The dial indicators are not firmly installed, resulting in inaccurate readings;

[0007] 2. During the process of jacking the housing with the jackscrew or jack, since it is manual operation, it is very difficult to make the thrust disc move synchronously and uniformly. Therefore, during the process of jacking the housing, the thrust housing will move instantaneously and accelerate, resulting in the dial indicators being instantaneously overloaded, causing the displacement of the dial indicator frame and the distortion of the readings;

[0008] 3. Different operators have different installation positions of the dial indicators and different reading habits, resulting in inconsistent results among different operators.

[0009] 4. Due to too many influencing factors during the operation process, multiple measurements are often required, so the calculation amount is very large and it is easy to make calculation errors.

[0010] Therefore, there is an urgent need on site for a method for measuring the axial clearance of a thrust bearing that is accurate in measurement and not affected by the installation and reading errors of the dial indicators. Summary of the Invention

[0011] The technical problem to be solved by the present invention is: to provide a method for measuring the axial clearance of a steam turbine thrust bearing, which can measure and calculate the axial clearance of the thrust bearing without installing dial indicators, is easy to operate, and the measurement result is accurate.

[0012] A method for measuring the axial clearance of a steam turbine thrust bearing according to the present invention includes the following steps:

[0013] Step S1: Mark 4 measurement points at the horizontal positions of the thrust bearing housing successively, and set 1 measurement point on the No. 2 coupling wheel.

[0014] Step S2: Use a laser tracker and a target ball to locate the horizontal positions of the front and rear housings and the coordinate of the marked point on the No. 2 coupling wheel.

[0015] Step S3: Then push the housing to move towards the adjustable end until the No. 2 coupling wheel moves. At this time, use the laser tracker and the target ball to locate the coordinates of the 5 measurement points again.

[0016] Step S4: Push the housing to move towards the generator end until the No. 2 coupling wheel moves. At this time, use the laser tracker and the target ball to locate the coordinates of the 5 measurement points again.

[0017] Step S5: After data collection, automatically calculate the thrust clearance result by using the displacements of the two sets of measurement points.

[0018] In a specific embodiment of the present invention, a first measurement point is provided at the top of the No. 2 coupling wheel facing the generator end side.

[0019] On one side of the thrust bearing housing facing the generator end, 2 measurement points are marked, namely the second measurement point and the third measurement point, which are arranged horizontally at 180°.

[0020] On one side of the thrust bearing housing facing the adjustable end, 2 measurement points are marked, namely the fourth measurement point and the fifth measurement point, which are arranged horizontally at 180°.

[0021] In a specific embodiment of the present invention, set up the laser tracker at an appropriate distance, start the laser tracker, and establish a coordinate system (X, Y, Z).

[0022] The vertical distance between the laser tracker and the thrust bearing housing is not less than 1 m.

[0023] In a specific embodiment of the present invention, the specific steps of Step S3 include:

[0024] Step S3-1: Push the thrust bearing housing towards the adjustable end and stop when the No. 2 coupling wheel is displaced.

[0025] Step S3-2: Place the target ball on the first measurement point, the second measurement point, the third measurement point, the fourth measurement point, and the fifth measurement point in sequence.

[0026] Step S3-3: The laser tracker forms the first measurement point (X1 ’ , Y1 ’ , Z1 ’ ), the second measurement point (X2 ’ , Y2 ’ , Z2 ’ ), the third measurement point (X3’ , Y3 ’ , Z3 ’ ), the fourth measurement point (X4 ’ , Y4 ’ , Z4 ’ ), the fifth measurement point (X5 ’ , Y5 ’ , Z5 ’ ) and record the readings.

[0027] In a specific embodiment of the present invention, the step S4 specifically includes:

[0028] Step S4-1: Push the thrust bearing housing towards the electrical end and stop after the No. 2 coupling wheel is displaced;

[0029] Step S4-2: Place the target ball at the first measurement point, the second measurement point, the third measurement point, the fourth measurement point, and the fifth measurement point in sequence;

[0030] Step S4-3: The laser tracker automatically locates the coordinates of the first measurement point (X1”, Y1”, Z1”), the second measurement point (X2”, Y2”, Z2”), the third measurement point (X3”, Y3”, Z3”), the fourth measurement point (X4”, Y4”, Z4”), and the fifth measurement point (X5”, Y5”, Z5”) in sequence and records the readings.

[0031] In a specific embodiment of the present invention, the step S5 specifically includes:

[0032] Step S5-1: Calculate the distance between the two coordinates of each measurement point;

[0033] Step S5-2: Calculate the thrust clearance using the distance.

[0034] In a specific embodiment of the present invention, in the step S5-1, the distance of each measurement point is calculated as shown in formula (1):

[0035]

[0036] where i is a natural number from 1 to 5.

[0037] In a specific embodiment of the present invention, in the step S5-2, the calculation method of the thrust clearance is:

[0038] Δh = (Δ1 + Δ2 + Δ3 + Δ4) / 4 - Δ5 (2).

[0039] In a specific embodiment of the present invention, the laser tracker includes an automatic calculation module and a collection module,

[0040] The collection module is used to collect the coordinates of each measurement point;

[0041] The automatic calculation module is used to automatically calculate the thrust clearance by using the coordinates collected by the collection module.

[0042] Compared with the prior art, the method for measuring the axial clearance of the thrust bearing of a steam turbine according to the present invention has the following beneficial effects:

[0043] (1) Utilize the high-precision measurement ability of the laser tracker to accurately measure the thrust bearing in a nuclear power plant to obtain the actual position and state of the bearing. The working principle of the laser tracker is to emit a laser beam and then calculate the position and moving distance of an object by measuring the time when the laser beam is reflected back. Therefore, it has very high precision.

[0044] After obtaining the actual position and state of the bearing, further process and analyze the measurement data through a specially designed algorithm to accurately calculate the clearance of the thrust bearing. This algorithm can effectively process the measurement data of the laser tracker and further improve the accuracy of clearance measurement.

[0045] (2) This high-precision measurement method can effectively improve the operation efficiency of a nuclear power plant, reduce maintenance costs, and improve economic benefits. Description of the Drawings

[0046] Figure 1 Schematic diagram showing the laser tracker measuring the axial clearance of the thrust bearing of a steam turbine;

[0047] In the figure, 1 - electrical end, 2 - adjusting end, 3 - laser tracker, 4 - No. 2 coupling, 5 - thrust bearing housing, 6 - first measurement point, 7 - second measurement point, 8 - third measurement point, 9 - fourth measurement point, 10 - fifth measurement point, 11 - target ball. Detailed Embodiment

[0048] To further understand the present invention, the implementation scheme of the present invention will be described below in conjunction with embodiments. However, it should be understood that these descriptions are only for further explaining the features and advantages of the present invention and not for limiting the present invention.

[0049] The embodiment of the present invention discloses a method for measuring the axial clearance of the thrust bearing of a steam turbine, including the following steps:

[0050] Step S1: Mark 4 measurement points at the front and rear horizontal positions of the thrust bearing housing 5, and set 1 measurement point on the No. 2 coupling 4, as Figure 1 shown;

[0051] A first measurement point 6 is provided at the top of the No. 2 coupling 4 facing the electrical end 1 side,

[0052] On one side of the thrust bearing housing 5 facing the electrical end 1, two measurement points are marked, namely the second measurement point 7 and the third measurement point 8, which are arranged horizontally at 180°;

[0053] On one side of the thrust bearing housing 5 facing the adjustment end 2, two measurement points are marked, namely the fourth measurement point 9 and the fifth measurement point 10, which are arranged horizontally at 180°;

[0054] Step S2: Set up a laser tracker at an appropriate distance (the measuring head of the laser tracker will follow the rotation of the ball, so there is no need to specify a specific angle, and the distance is determined according to the on-site space, trying not to affect on-site maintenance). Start the laser tracker and establish a coordinate system (X, Y, Z);

[0055] The target ball is a long rod with a highly polished metal sphere at the head, which is used to receive and reflect signals. During measurement, the target ball can be pressed against the measurement point.

[0056] Use the laser tracker and the target ball to locate the horizontal positions of the front and rear housings and the coordinates of the marking points of the No. 2 coupling;

[0057] Step S3: Then push the housing towards the adjustment end 2 until the No. 2 coupling 4 moves. At this time, use the laser tracker 3 and the target ball 11 to locate the coordinates of the 5 measurement points;

[0058] Specifically, it includes the following steps:

[0059] Step S3-1: Push the thrust bearing housing 5 towards the adjustment end 2 and stop after the No. 2 coupling 4 has a displacement;

[0060] Step S3-2: Place the target ball 11 successively at the first measurement point 6, the second measurement point 7, the third measurement point 8, the fourth measurement point 9, and the fifth measurement point 10;

[0061] Step S3-3: The laser tracker 3 successively forms the coordinates of the first measurement point 6 (X1 ’ , Y1 ’ , Z1 ’ ), the second measurement point 7 (X2 ’ , Y2 ’ , Z2 ’ ), the third measurement point 8 (X3 ’ , Y3 ’ , Z3 ’ ), the fourth measurement point 9 (X4 ’ , Y4 ’ , Z4 ’ ), the fifth measurement point 10 (X5 ’ , Y5 ’ , Z5 ’ ) and records the readings;

[0062] Step S4: Push the housing towards the electrical end 1 until the No. 2 coupling 4 moves, and then use the laser tracker 3 and the target ball 11 to locate the coordinates of the 5 measurement points again;

[0063] Specifically, it includes the following steps:

[0064] Step S4-1: Push the thrust bearing housing 5 towards the electrical end 1 and stop after the No. 2 coupling 4 is displaced;

[0065] Step S4-2: Place the target ball 11 at the first measurement point 6, the second measurement point 7, the third measurement point 8, the fourth measurement point 9, and the fifth measurement point 10 in sequence;

[0066] Step S4-3: The laser tracker 3 automatically locates the coordinates of the first measurement point 6 (X1”, Y1”, Z1”), the second measurement point 7 (X2”, Y2”, Z2”), the third measurement point 8 (X3”, Y3”, Z3”), the fourth measurement point 9 (X4”, Y4”, Z4”), and the fifth measurement point 10 (X5”, Y5”, Z5”) in sequence and records the readings;

[0067] Step S5: After data collection, automatically calculate the thrust clearance result using the displacements of the two sets of measurement points.

[0068] Specifically, it includes:

[0069] Calculate the distances of each measurement point, as shown in formula (1):

[0070]

[0071] where i is a natural number from 1 to 5;

[0072] Calculate the thrust clearance using the distances of each measurement point, as shown in formula (2):

[0073] Δh = (Δ1 + Δ2 + Δ3 + Δ4) / 4 - Δ5 (2).

[0074] In the present invention, the laser tracker includes an automatic calculation module and a collection module.

[0075] The collection module is used to collect the coordinates of each measurement point;

[0076] The automatic calculation module is used to automatically calculate the thrust clearance using the coordinates collected by the collection module.

[0077] The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0078] The foregoing description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for measuring the axial clearance of a steam turbine thrust bearing, characterized in that: The following steps are involved: Step S1: Mark four measuring points in the horizontal position of the thrust bearing housing, and set one measuring point on the No. 2 pair of wheels; Step S2: Use a laser tracker and a target ball to locate the horizontal position of the front and rear shells and the coordinates of the No. 2 wheel mark point; Step S3: Then push the housing to move toward the adjustment end until the No. 2 pair of wheels moves, and at this time use the laser tracker and the target ball to locate the coordinates of the five measurement points again; Step S4: Push the housing toward the electric end until the No. 2 pair of wheels moves, and then use the laser tracker and target ball to locate the coordinates of the five measurement points again; Step S5: After data collection, the thrust clearance result is automatically calculated using the displacement of the two measurement points.

2. The method for measuring the axial clearance of a steam turbine thrust bearing according to claim 1, characterized in that: The top of the No. 2 pair of wheels facing the electric end is provided with a first measuring point. Two measuring points are marked on the side of the thrust bearing housing facing the electrical end, namely the second measuring point and the third measuring point, which are arranged horizontally at 180°; Two measuring points are marked on the side of the thrust bearing housing facing the adjustment end, namely the fourth measuring point and the fifth measuring point, which are arranged horizontally at 180°.

3. The method for measuring the axial clearance of a steam turbine thrust bearing according to claim 1, characterized in that: Select a suitable distance to set up the laser tracker, start the laser tracker, and establish the coordinate system (X, Y, Z); The vertical distance between the laser tracker and the thrust bearing housing is not less than 1 m.

4. The method for measuring the axial clearance of a steam turbine thrust bearing according to claim 1, characterized in that: The step S3 specifically includes: Step S3-1: Push the thrust bearing housing to move toward the adjustment end until the No. 2 wheel pair is displaced and stops; Step S3-2: placing the target ball at the first measuring point, the second measuring point, the third measuring point, the fourth measuring point, and the fifth measuring point in sequence; Step S3-3: The laser tracker forms the first measurement point (X1 ’ 、Y1 ’ 、Z1 ’ ), the second measuring point (X2 ’ 、Y2 ’ 、Z2 ’ )、The third measuring point (X3 ’ 、Y3 ’ 、Z3 ’ )、The fourth measuring point (X4 ’ 、Y4 ’ 、Z4 ’ )、The fifth measuring point (X5 ’ 、Y5 ’ 、Z5 ’ ) coordinates and record the readings.

5. The method for measuring the axial clearance of a steam turbine thrust bearing according to claim 1, characterized in that: The step S4 specifically includes: Step S4-1: Push the thrust bearing housing toward the electric end until the No. 2 wheel pair is displaced and stops; Step S4-2: placing the target ball at the first measuring point, the second measuring point, the third measuring point, the fourth measuring point, and the fifth measuring point in sequence; Step S4-3: The laser tracker automatically locates the coordinates of the first measuring point (X1”, Y1”, Z1”), the second measuring point (X2”, Y2”, Z2”), the third measuring point (X3”, Y3”, Z3”), the fourth measuring point (X4”, Y4”, Z4”), and the fifth measuring point (X5”, Y5”, Z5”) in sequence and records the readings.

6. The method for measuring the axial clearance of a steam turbine thrust bearing according to claim 1, characterized in that: The step S5 specifically includes: Step S5-1: Calculate the distance between the two coordinates of each measurement point; Step S5-2: Calculate the thrust clearance using the distance.

7. The method for measuring the axial clearance of a steam turbine thrust bearing according to claim 6, characterized in that: In step S5-1, the distances of the various measuring points are calculated, as shown in formula (1): Where i is a natural number from 1 to 5.

8. The method for measuring the axial clearance of a steam turbine thrust bearing according to claim 6, characterized in that: In step S5-2, the thrust clearance is calculated as follows: Δh=(Δ1+Δ2+Δ3+Δ4) / 4-Δ5 (2).

9. The method for measuring the axial clearance of a steam turbine thrust bearing according to claim 1, characterized in that: The laser tracker includes an automatic calculation module and a collection module. The acquisition module is used to acquire the coordinates of each measurement point; The automatic calculation module is used to automatically calculate the thrust clearance using the coordinates collected by the collection module.

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