A drilling die and drilling method for processing a drain hole of a steam turbine diaphragm outer ring

Abstract

A kind of drilling die and drilling method for steam turbine diaphragm outer ring drain hole processing, it relates to a kind of drilling die.The present application is to solve the problem that the current drill plate is prone to tilt, string movement and the error of manufacturing tolerance or alignment when using, affects the processing of drain hole.The present application uses the way that the profile line of the bevel of observation hole is tangent to the profile line of hollow guide vane to ensure that the positioning hole on the drill plate is in the position accurate within the profile line range of hollow guide vane, drill bit passes through positioning hole to drill diaphragm outer ring, and then ensure that the position of processed drain hole on diaphragm outer ring is accurate.After a group of drain holes are drilled, the drilling die is moved along the circumferential direction of the inner hole of diaphragm outer ring, the profile line of the next hollow guide vane is observed through the profile line comparison observation hole, then the next group of drain holes are drilled, and the above process is repeated to complete the processing of several groups of drain holes on diaphragm outer ring.The present application is used for the drilling processing of diaphragm outer ring drain hole.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of drilling mould and drilling method, specifically relates to a kind of drilling mould and drilling method for processing drain hole of steam turbine diaphragm outer ring, belong to steam turbine diaphragm processing technical field. BACKGROUND

[0002] Due to long time running in wet steam environment, diaphragm vane often appears serious water erosion phenomenon in the low pressure last stage diaphragm of high-power steam turbine, causes vane damage, fracture, leads to unit vibration aggravation, affects unit operation safety.At present, the most effective solution to solve the last stage diaphragm guide vane water erosion problem is to process drain hole on the inner and outer ring of last stage diaphragm to form drain passage with hollow guide vane, and the condensed water is discharged through the drain passage.Because the inner hole of diaphragm outer ring is curved surface structure, when processing drain hole in the inner hole, drill bit will appear sliding, and cannot be processed normally.Therefore, positioning drill tool is needed to position and fix drill bit when drilling, to ensure the stability when drilling.

[0003] For example, the utility model patent with publication number CN206689494U discloses a stator holding ring drain hole processing tool, the technical scheme of the patent is to place the "triple" type drill jig plate provided with three sets of positioning holes on the diaphragm outer ring to be processed, drill the first set of drain holes through the first set of positioning holes, then insert positioning pins into the first set of positioning holes of the drill jig plate and the first set of drain holes drilled, position the drill jig plate and the first set of drain holes of the stator holding ring through the positioning pins, adjust the position of the drill bit, and let the drill bit pass through the second set and the third set of positioning holes on the drill jig plate to process the second set and the third set of drain holes;after the third set of drain holes are processed, move the device to the next drilling position along the circumferential direction of the inner hole of the diaphragm outer ring, align the first set of positioning holes on the drill jig plate with the third set of drain holes at the previous processing position by inserting positioning pins, adjust the position of the drill bit again, and process the fourth set and the fifth set of drain holes through the second set and the third set of positioning holes on the drill jig plate, repeat the above steps, and complete the processing of the several sets of drain holes on the diaphragm outer ring.

[0004] However, the above device has the following disadvantages: first, the "triple" type drill jig plate is provided with three sets of positioning holes, which leads to large volume and weight of the drill jig plate and the entire device, and the device is prone to tilting and shifting during use, affecting the positioning of the drill bit;and the processing of the drain holes on the outer ring needs to move the drill jig tool in the circumferential direction several times, which is difficult to operate during shifting and alignment again, affecting the processing efficiency.

[0005] Secondly, when the distance between the hydrophobic holes is ensured by taking the first set of positioning holes of the drilling template as the positioning reference of the next drilling position, if the processing of all groups of hydrophobic holes of the outer ring of the partition plate is completed, the tolerance during the manufacturing of the drilling template and the error during the alignment of the next drilling position will gradually accumulate, so that the hydrophobic holes drilled later are not in the correct position, and then the hydrophobic holes and the hollow guide vane cannot form a hydrophobic passage, which does not meet the use requirements; if the position of the hollow guide vane is forcibly changed and the hydrophobic holes not in the correct position are connected, the size requirement of the guide vane throat of the outer ring of the partition plate is not met, which affects the flow efficiency of the unit.

[0006] In summary, how to solve the above technical problems by proposing a new drilling mold has become a problem that needs to be solved by the technical personnel in the field at present. SUMMARY

[0007] The present application aims at the shortcomings of the prior art and further provides a drilling mold and a drilling method for processing hydrophobic holes of a turbine partition plate outer ring.

[0008] The technical scheme of the present application is: a drilling mold and a drilling method for processing hydrophobic holes of a turbine partition plate outer ring, comprising a drilling template, a first fixed plate, a second fixed plate and a third fixed plate.

[0009] The third fixed plate is arranged in parallel with the first fixed plate having a long hole, and a positioning key is installed on one side surface of the first fixed plate; and the positioning key is arranged at 90° with the long hole.

[0010] The first fixed plate is welded and connected with the second fixed plate, the third fixed plate is connected with the second fixed plate through bolts, and a plurality of jacking screws are installed on the second fixed plate and the third fixed plate.

[0011] The drilling template is connected with the first fixed plate through bolts, the drilling template is provided with a second key groove matched with the positioning key, a set of positioning holes for drilling and processing the partition plate outer ring, and a plurality of profile line comparison observation holes with a right trapezoidal cross section, and the hypotenuse of each profile line comparison observation hole is tangent to the profile of the hollow guide vane, and the axis direction of the profile line comparison observation hole and the positioning hole is perpendicular to the second key groove.

[0012] The present application further provides a turbine partition plate outer ring hydrophobic hole drilling method, which is specifically performed according to the following steps:

[0013] Step one, the partition plate outer ring, the partition plate inner ring and each hollow guide vane are pre-assembled according to the use requirements, and then the profile line of the root of each hollow guide vane in the inner hole position of the partition plate outer ring is marked in the inner circumferential surface direction of the partition plate outer ring;

[0014] Step two, after the transfer printing is completed, the partition plate outer ring, the hollow guide vane and the partition plate inner ring are separated, the drilling mold is assembled, the drilling mold is fixed on the partition plate outer ring, and the drilling of the drainage hole is prepared;

[0015] Step three, the drilling mold is moved along the inner hole circumferential direction of the partition plate outer ring, at the same time, the profile line of the hollow guide vane is observed through the two profile line comparison observation holes, when the inclined edge of the two profile line comparison observation holes is tangent to the profile line of the hollow guide vane, the movement of the drilling mold is stopped; the top screw on the third fixed plate is screwed first, so that the end surface with small cross section of the partition plate outer ring abuts against the first fixed plate; then the top screw on the second fixed plate is screwed, so that the inner circumferential surface of the partition plate outer ring abuts against the drilling mold plate;

[0016] Step four, the drill bit drills the first group of drainage holes through the positioning hole on the drilling mold plate, after the first group of drainage holes are processed, the top screws on the second fixed plate and the third fixed plate are loosened, and then the process of step three is repeated to complete the processing of a plurality of groups of drainage holes on the partition plate outer ring.

[0017] Compared with the prior art, the present application has the following effects:

[0018] 1. The drilling mold plate 1 of the present application is small in size and light in weight, and the partition plate outer ring 5 is abutted against the drilling mold of the present application by screwing the top screws 3-1 on the third fixed plate 4 and the second fixed plate 3, so that a "full-enclosing" fixing structure is formed, and the instability of the fixing during the drilling process is avoided.

[0019] 2. The partition plate outer ring 5, the partition plate inner ring and the hollow guide vane are pre-assembled at the correct position, the profile lines of all the hollow guide vanes are transferred on the inner circumferential surface of the partition plate outer ring 5, the profile line of the hollow guide vane is observed through the profile line comparison observation hole 1-3, and the position of the positioning hole 1-1 on the drilling mold plate 1 is ensured to be accurate within the range of the profile line of the hollow guide vane by the tangent mode of the inclined edge of the profile line comparison observation hole 1-3 and the profile line of the hollow guide vane, so that the drill bit passes through the positioning hole 1-1 to drill the partition plate outer ring 5, and the position accuracy of the processed drainage hole on the partition plate outer ring 5 is ensured.

[0020] After a group of drainage holes are drilled, the drilling mold is moved along the inner hole circumferential direction of the partition plate outer ring 5, the profile line of the next hollow guide vane is observed through the profile line comparison observation hole 1-3, and then the next group of drainage holes is drilled, so that the influence of the manufacturing tolerance or the error during the alignment on the processing of the drainage hole is avoided; the subsequent hollow guide vane is reassembled only by the profile line position during the pre-assembly, so that the drainage passage of the inner hole drainage hole of the outer ring and the hollow guide vane is ensured to meet the use requirements. BRIEF DESCRIPTION OF DRAWINGS

[0021] Fig. 1 is a side view of the present application;

[0022] Fig. 2 is the front view of the drill jig 1 of the present application, wherein the double-dot dashed line represents the profile line of the hollow guide vane imprinted in the direction of the inner circumferential surface of the partition outer ring 5;

[0023] Fig. 3 is the top view of the first fixed plate 2 of the present application.

[0024] In the figure: 1, drill jig, 1-1, positioning hole, 1-2, weight-reducing hole, 1-3, profile line comparison observation hole, 2, first fixed plate, 2-1, positioning key, 2-2, bolt, 2-3, long hole, 3, second fixed plate, 3-1, jacking screw, 4, third fixed plate, 5, partition outer ring. DETAILED DESCRIPTION

[0025] In order to make the invention purpose, features and advantages of the present application more obvious and easy to understand, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application.

[0026] Specific embodiment one: in combination with Figs. 1-3 In this embodiment, the drill jig for processing the drain hole of the turbine partition outer ring includes a drill jig plate 1, a first fixed plate 2, a second fixed plate 3 and a third fixed plate 4.

[0027] The third fixed plate 4 is arranged in parallel with the first fixed plate 2 having the long hole 2-3, and the positioning key 2-1 is installed on one side surface of the first fixed plate 2; and the positioning key 2-1 is arranged at 90° with the long hole 2-3.

[0028] The first fixed plate 2 is welded and connected with the second fixed plate 3, the third fixed plate 4 is connected with the second fixed plate 3 through the bolt 2-2, and the second fixed plate 3 and the third fixed plate 4 are both installed with a plurality of jacking screws 3-1.

[0029] The drill jig plate 1 is connected with the first fixed plate 2 through the bolt 2-2, the drill jig plate 1 is provided with the second key groove matched with the positioning key 2-1, a group of positioning holes 1-1 for drill processing of the partition outer ring 5 and a plurality of profile line comparison observation holes 1-3 with right-trapezoidal cross section, and the hypotenuse of each profile line comparison observation hole 1-3 is tangent to the profile of the hollow guide vane, and the axis direction of the profile line comparison observation hole 1-3 and the positioning hole 1-1 is perpendicular to the second key groove.

[0030] In this embodiment, the threaded head of the jacking screw 3-1 is stacked with copper, so that the surface of the partition outer ring 5 is avoided from being scratched by the jacking screw 3-1.

[0031] The drill template 1 and the first fixed plate 2 are in threaded connection structure in the embodiment, and different sizes of the baffle outer ring 5 can be processed by replacing the drill template 1 of different sizes.

[0032] Specific implementation method two: combined with Fig. 2 and Fig. 3 The embodiment is described, and the number of profile line comparison observation holes 1-3 is 2 in the embodiment.

[0033] Further, the number of positioning holes 1-1 is 3.

[0034] Further, the weight reduction hole 1-2 is arranged on the drill template 1. In this way, the weight of the drill template 1 is reduced, and the labor intensity of the operator is reduced.

[0035] The other components and connection modes are the same as those in the specific implementation method one.

[0036] Specific implementation method three: combined with Figs. 1-3 The embodiment is described, and the steam turbine baffle outer ring drain hole drilling method in the embodiment is performed according to the following steps.

[0037] Step one, the baffle outer ring 5, the baffle inner ring and each hollow guide vane are pre-assembled according to the use requirements, and then the profile lines of the positions of the root portions of each hollow guide vane in the inner hole of the baffle outer ring 5 are respectively transferred in the inner circumferential surface direction of the baffle outer ring 5;

[0038] Step two, after the transfer is completed, the baffle outer ring 5, the hollow guide vane and the baffle inner ring are separated, the drilling mold is assembled, the drilling mold is fixed on the baffle outer ring 5, and the drilling of the drain hole is prepared;

[0039] Step three, the drilling mold is moved along the inner hole circumferential direction of the baffle outer ring 5, at the same time, the profile line of the hollow guide vane is observed through the two profile line comparison observation holes 1-3, when the oblique edges of the two profile line comparison observation holes 1-3 are tangent to the profile line of the hollow guide vane, the movement of the drilling mold is stopped; the top screw 3-1 on the third fixed plate 4 is screwed first, so that the end surface with small cross-sectional area of the baffle outer ring 5 is abutted against the first fixed plate 2; then the top screw 3-1 on the second fixed plate 3 is screwed, so that the inner circumferential surface of the baffle outer ring 5 is abutted against the drill template 1;

[0040] Step four, the drill bit passes through the positioning hole 1-1 on the drill template 1 to drill the first group of drain holes, after the first group of drain holes is processed, the top screws 3-1 on the second fixed plate 3 and the third fixed plate 4 are loosened, and then the process of step three is repeated to complete the processing of the several groups of drain holes on the baffle outer ring 5.

[0041] The other components and connection modes are the same as those in the specific implementation method one or two.

[0042] Working principle

[0043] Combination Figs. 1-3 The working principle of the present application is explained as follows:

[0044] Firstly, the partition plate outer ring 5, the partition plate inner ring and each hollow guide vane are pre-assembled according to the use requirements, and the profile line of the root of each hollow guide vane in the inner hole position of the partition plate outer ring 5 is respectively transferred in the inner circumferential surface direction of the partition plate outer ring 5;

[0045] Then, the partition plate outer ring 5, the hollow guide vane and the partition plate inner ring are separated, the drilling mold of the present application is fixed on the partition plate outer ring 5, and the drilling mold is moved along the inner hole circumferential direction of the partition plate outer ring 5, at the same time, the profile line of the hollow guide vane is observed through the two profile line comparison observation holes 1-3, when the oblique edge of the two profile line comparison observation holes 1-3 is tangent to the profile line of the hollow guide vane, the movement of the drilling mold is stopped, and the position of the positioning hole 1-1 on the drilling mold plate 1 is ensured to be within the range of the profile line of the hollow guide vane by the way that the oblique edge of the profile line comparison observation hole 1-3 is tangent to the profile line of the hollow guide vane. The jacking screw 3-1 on the third fixed plate 4 is screwed, so that the end surface with small cross-sectional area of the partition plate outer ring 5 is abutted against the first fixed plate 2; then the jacking screw 3-1 on the second fixed plate 3 is screwed, so that the inner circumferential surface of the partition plate outer ring 5 is abutted against the drilling mold plate 1.

[0046] Finally, the drill bit passes through the positioning hole 1-1 to perform the drilling processing of the first group of hydrophobic holes, after the first group of hydrophobic holes is processed, the jacking screw 3-1 on the second fixed plate 3 and the third fixed plate 4 is loosened; after the hydrophobic holes are drilled, the drilling mold is moved along the inner hole circumferential direction of the partition plate outer ring 5, the profile line of the next hollow guide vane is observed through the profile line comparison observation hole 1-3, then the next group of hydrophobic holes is drilled, the above process is repeated, the processing of the several groups of hydrophobic holes on the partition plate outer ring 5 is completed, and the subsequent hollow guide vane is reassembled only by the profile line position during the pre-assembly, so as to ensure that the hydrophobic holes in the inner hole of the outer ring and the hollow guide vane form a hydrophobic channel and meet the use requirements.

[0047] The present application has been disclosed in the above preferred embodiments, however, it is not intended to limit the present application, any person skilled in the art, without departing from the technical solution of the present application, according to the technical essence of the present application, any simple modification, equivalent change and modification of the above embodiments are still within the scope of the technical solution of the present application.

Claims

1. A method for drilling drain holes in the outer ring of a turbine diaphragm, the drilling jig used in the method comprising a drilling template (1), a first fixed plate (2), a second fixed plate (3) and a third fixed plate (4); The third fixed plate (4) is arranged in parallel with the first fixed plate (2) having a long hole (2-3) formed therein, and the first fixed plate (2) is provided with a positioning key (2-1) on one side surface thereof; and the positioning key (2-1) is arranged at an angle of 90° with the long hole (2-3); The first fixed plate (2) is welded to the second fixed plate (3), and the third fixed plate (4) is connected to the second fixed plate (3) by means of a bolt (2-2); and the second fixed plate (3) and the third fixed plate (4) are each provided with a plurality of clamping screws (3-1); The drilling template (1) is connected to the first fixed plate (2) by means of a bolt (2-2); the drilling template (1) is provided with a second key groove matched with the positioning key (2-1), a group of positioning holes (1-1) for drilling the outer ring (5) of the diaphragm and a plurality of profile line comparison observation holes (1-3) having a right trapezoidal cross section; Or the drilling template (1) is provided with a weight-reducing hole (1-2); the drilling template (1) is provided with a second key groove matched with the positioning key (2-1), three positioning holes (1-1) for drilling the outer ring (5) of the diaphragm and two profile line comparison observation holes (1-3) having a right trapezoidal cross section; the oblique edges of each profile line comparison observation hole (1-3) are tangent to the profile of the hollow guide vane; and the axis directions of the profile line comparison observation holes (1-3) and the positioning holes (1-1) are perpendicular to the second key groove; characterized in that The method is performed according to the following steps: Step 1: The outer ring (5) of the diaphragm, the inner ring of the diaphragm and the hollow guide vanes are pre-assembled according to the requirements, and then the profile lines of the positions of the roots of each hollow guide vane in the inner hole of the outer ring (5) of the diaphragm are marked in the circumferential direction of the inner hole of the outer ring (5) of the diaphragm; Step 2: After the marking is completed, the outer ring (5) of the diaphragm, the hollow guide vanes and the inner ring of the diaphragm are separated, the drilling jig is assembled and fixed on the outer ring (5) of the diaphragm, and the drilling of the drain holes is prepared; Step 3: The drilling jig is moved along the circumferential direction of the inner hole of the outer ring (5) of the diaphragm, and at the same time, the profile of the hollow guide vane is observed through the two profile line comparison observation holes (1-3); when the oblique edges of the two profile line comparison observation holes (1-3) are tangent to the profile of the hollow guide vane, the movement of the drilling jig is stopped; the clamping screws (3-1) on the third fixed plate (4) are screwed first, so that the end surface of the outer ring (5) of the diaphragm with a small cross-sectional area is abutted against the first fixed plate (2); then the clamping screws (3-1) on the second fixed plate (3) are screwed, so that the inner circumferential surface of the outer ring (5) of the diaphragm is abutted against the drilling template (1); Step 4: The drill bit drills the first group of drain holes through the positioning holes (1-1) in the drilling template (1); after the first group of drain holes are drilled, the clamping screws (3-1) on the second fixed plate (3) and the third fixed plate (4) are loosened, and then the process of Step 3 is repeated to complete the drilling of the groups of drain holes in the outer ring (5) of the diaphragm.

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