A cylindrical gap sealing gap shape control structure

Abstract

The present invention discloses a cylindrical gap sealing gap shape control structure, comprising a rotating shaft, a sealing stator and a fixed housing, a sealing gap is formed between the outer cylindrical surface of the rotating shaft and the inner cylindrical surface of the sealing stator, a first axial section located on the low-pressure medium side and a second axial section located on the high-pressure medium side of the fixed housing are respectively fixed with a control element and a test element for testing the axial position of the sealing stator, the control element comprises an active control element and a passive clamping element for driving the axial position of the sealing stator to change, two active control elements, two passive clamping elements and two test elements are respectively fixed on the first axial section and the second axial section, and the active control element, the passive clamping element and the test element are all in contact with the outer cylindrical surface of the sealing stator. The present invention realizes the control and testing of different sealing gap shapes including concentric annular gaps, eccentric annular gaps, three-dimensional inclined gaps, etc. by arranging the sealing stator axial position control element and the test element on two different axial sections, and can simulate the sealing gap shapes corresponding to different installation states of the sealing stator in engineering practice.

Description

Technical Field

[0001] The invention relates to the field of cylindrical surface sealing test, and in particular to a cylindrical surface gap sealing gap shape regulating structure. Background Art

[0002] Fixed stator type cylindrical gap seals, including labyrinth seals, honeycomb seals and hole-type damping seals, are commonly used sealing forms for steam turbines, gas turbines and various turbine machinery. They have the advantages of simple structure, easy installation and high reliability. The main structure of the fixed stator type cylindrical seal is a pair of seal pairs consisting of a rotating shaft or sleeve as a sealing rotor and a sealing stator fixedly installed on a stationary housing. There is generally a certain radial gap between the inner surface of the sealing stator and the outer surface of the sealing rotor to accommodate the installation deviation of the sealing stator, the radial runout or bending deformation of the rotating shaft, and this gap also becomes the main channel for medium leakage. The sealing gap value and its shape have a significant impact on the leakage characteristics and dynamic characteristics of the fixed stator type cylindrical seal. In the actual application of cylindrical gap seals, deviations such as misalignment and rotor deflection often occur due to machining errors and assembly errors of the sealing stator and rotor, which makes the sealing gap present an eccentric annular gap, a three-dimensional inclined gap and other shapes. How to accurately construct and test sealing gaps of different shapes in laboratory simulated working condition tests to simulate various gap shapes that may appear in engineering practice is crucial for studying the leakage and dynamic characteristics of fixed stator cylindrical seals. Existing fixed stator cylindrical seal test platforms generally have difficulty in achieving arbitrary adjustment of the sealing gap shape. Different sealing gap values ​​can only be constructed by using rotors or stators of different radial sizes, and the construction of axially inclined gaps cannot be achieved, which restricts the study of the influence of cylindrical sealing gap shape. Summary of the invention

[0003] In order to solve the problem that the existing cylindrical gap sealing test platform is difficult to realize the axial tilted gap shape structure, the present invention provides a cylindrical gap sealing gap shape control structure which is convenient and accurate to control.

[0004] The technical solution adopted by the present invention is:

[0005] A cylindrical gap sealing gap shape control structure comprises a rotating shaft, a sealing stator and a fixed shell, one axial side of which is a high-pressure medium side, and the other side is a low-pressure medium side, the sealing stator is located between the fixed shell and the rotating shaft, and a sealing gap is formed between the outer cylindrical surface of the rotating shaft and the inner cylindrical surface of the sealing stator, and a first axial section located on the low-pressure medium side and a second axial section located on the high-pressure medium side of the fixed shell are fixed with a control element and a test element for testing the axial position of the sealing stator, the control element comprises an active control element and a passive clamping element for driving the axial position of the sealing stator to change; the active control element, the passive clamping element and the test element are all in contact with the outer cylindrical surface of the sealing stator.

[0006] Furthermore, a first active regulating element, a second active regulating element, a first passive clamping element, a second passive clamping element, a first test element and a second test element are provided on the first axial section, and a third active regulating element, a fourth active regulating element, a third passive clamping element, a fourth passive clamping element, a third test element and a fourth test element are provided on the second axial section.

[0007] Furthermore, the first active regulating element and the second active regulating element are arranged at an angle of °, and the third active regulating element and the fourth active regulating element are also arranged at an angle of °. The active regulating elements may be screws or screw micrometers.

[0008] Furthermore, the first passive clamping element and the first active regulating element, the second passive clamping element and the second active regulating element, the third passive clamping element and the third active regulating element, and the fourth passive clamping element and the fourth active regulating element are all arranged at an angle of .

[0009] Furthermore, the first test element and the second test element are arranged at a certain angle, and the third test element and the fourth test element are also arranged at a certain angle, and the angle can be any value other than °. The test elements include a displacement sensor and a displacement sensor seat fixed on a fixed shell.

[0010] Furthermore, the passive clamping element is a pneumatic element, including a pressure cylinder body, a pneumatic joint, a piston push rod and a third auxiliary sealing ring. The pressure cylinder body is fixed on a fixed shell, the pneumatic joint is fixed on the pressure cylinder body, and a third auxiliary sealing ring is provided between the piston push rod and the pressure cylinder body. One end of the piston push rod is in contact with the outer cylindrical surface of the sealing stator, and the other end of the piston push rod is located in the pressure cylinder body.

[0011] Alternatively, the passive pressing element may also be a tightening screw.

[0012] Furthermore, a first auxiliary sealing ring and a second auxiliary sealing ring are provided between the sealing stator and the fixed housing.

[0013] Furthermore, the inner cylindrical surface of the sealing stator is a hole-type damping sealing surface with evenly arranged holes.

[0014] Alternatively, the inner cylindrical surface of the sealing stator may be a smooth surface.

[0015] Alternatively, the inner cylindrical surface of the sealing stator is a labyrinth sealing surface with an annular groove.

[0016] Advantages and beneficial effects of the present invention

[0017] (1) By setting up several groups of control elements and test elements on two different axial sections, convenient and precise control of different gap shapes of fixed stator cylindrical seals can be achieved, including concentric annular, eccentric annular or three-dimensional inclined gaps, so as to simulate different sealing gaps formed by processing and assembly errors in actual engineering.

[0018] (2) The adjustment parts of all active control elements and passive clamping elements are arranged outside the fixed shell, and the passive clamping element can adopt a pneumatic structure, which can directly and conveniently adjust the shape of the sealing gap from the outside, and the work intensity is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a right view of the cylindrical gap sealing gap shape regulating structure of the first embodiment of the present invention;

[0020] Figure 2 It is a front view of the cylindrical gap sealing gap shape regulating structure of the first embodiment of the present invention;

[0021] Figure 3 It is a three-dimensional model diagram of the cylindrical gap sealing gap shape control structure of the first embodiment of the present invention;

[0022] Figure 4 It is a first axial cross-sectional view of the cylindrical gap sealing gap shape regulating structure of the first embodiment of the present invention;

[0023] Figure 5 It is a radial cross-sectional view of the cylindrical gap sealing gap shape regulating structure of the first embodiment of the present invention;

[0024] Figure 6 It is a structural diagram of a sealed stator of an implementation case of the present invention;

[0025] Figure 7 It is a schematic diagram of an axial cross section of an embodiment of the present invention when the sealing stator and the rotating shaft are in a concentric state;

[0026] Figure 8 It is a schematic diagram of an axial cross section of an embodiment of the present invention when the sealing stator and the rotating shaft are not concentric;

[0027] Fig. 9 Schematic diagram of the gap shape when the sealed stator and the rotating shaft are in a concentric state in an implementation example of the present invention;

[0028] Fig.10 It is a schematic diagram of the gap shape when the sealing stator and the rotating shaft are not centered in the implementation case of the present invention;

[0029] Fig.11 Schematic diagram of the gap shape when the sealing stator and the rotating shaft are in a skewed state in an implementation example of the present invention;

[0030] Fig.12 It is the first axial cross-sectional view of the cylindrical gap sealing gap shape regulating structure of the second implementation example of the present invention. DETAILED DESCRIPTION

[0031] Implementation Case 1

[0032] The implementation of the present invention is further described in detail with reference to the accompanying drawings.

[0033] refer to Figure 1 , 2 , 3, 4 and 5, a cylindrical gap sealing gap shape control structure, including a rotating shaft 1, a sealing stator 2 and a fixed housing 3, a sealing gap is formed between the outer cylindrical surface 11 of the rotating shaft and the inner cylindrical surface 24 of the sealing stator, and one axial side of the sealing stator 3 is the high-pressure medium side, and the other side is the low-pressure medium side. Under the action of the medium pressure difference, the sealing medium leaks from the high-pressure medium side to the low-pressure medium side through the sealing gap. The sealing stator 2 is located between the fixed housing 3 and the rotating shaft 1, wherein the rotating shaft 1 and the fixed housing 3 always maintain a concentric state, and the sealing stator 2 can move in the radial space formed by the rotating shaft 1 and the fixed housing 3. In order to ensure a reliable seal between the sealing stator 2 and the fixed housing 3, a first auxiliary sealing ring 21 and a second auxiliary sealing ring 22 are provided between the sealing stator 2 and the fixed housing 3.

[0034] A regulating element 4 and a testing element 5 for adjusting and testing the axial position of the sealing stator 2 are fixed on the fixed shell 3. The regulating element 4 includes an active regulating element 41 for driving the change of the axial position of the sealing stator 2 and a passive clamping element 42 for ensuring the positioning of the sealing stator 2. The active regulating element 41, the passive regulating element 42 and the testing element 5 are all in contact with the outer cylindrical surface 23 of the sealing stator.

[0035] According to a specific example of the present invention, the active control element 41 is a screw, and the axial position of the sealed stator 2 can be changed by changing the screwing depth of the screw. Two active control elements 41 are arranged circumferentially on an axial section, and the optimal value of the circumferential angle between two adjacent active control elements 41 is 90°, so that the axial position of the sealed stator 2 can be adjusted in two vertical directions.

[0036] According to a specific example of the present invention, the passive clamping element 42 includes a pressure cylinder body 45, a pneumatic joint 44, a piston push rod 43 and a third auxiliary sealing ring 46. The pressure cylinder body 45 is fixed on the fixed shell 3, the pneumatic joint 44 is fixed on the pressure cylinder body 45, and a third auxiliary sealing ring 46 is provided between the piston push rod 43 and the pressure cylinder body 45. One end of the piston push rod 43 contacts the outer cylindrical surface 23 of the sealing stator, and the other end of the piston push rod 43 is located in the pressure cylinder body 45; a closed pressure chamber is formed in the pressure cylinder body 45, and the sealing of one end thereof is achieved by the piston push rod 43 and the third auxiliary sealing ring 46, and the sealing of the other end is achieved by the pneumatic joint 44; after the active control element 41 adjusts the position of the sealing stator 2 into place, a pressurized medium is rushed into the pressure cylinder body 45 through an external pressure source, and the medium pressure acts on one end of the piston push rod 43, and the piston push rod 43 presses the outer cylindrical surface 23 of the sealing stator, thereby maintaining the axial position of the sealing stator 2. According to a specific example of the present invention, two passive clamping elements 42 are arranged along the circumferential direction on an axial section, and each passive clamping element 42 is arranged at an angle of 180° circumferentially with each active control element 41 on the same axial section mentioned above, so as to ensure that the passive clamping element 42 can reliably clamp the sealing stator 2 in the axial adjustment direction of the sealing stator 2.

[0037] The test element 5 includes a displacement sensor 51 and a displacement sensor seat 52 fixed on the fixed housing, and the displacement sensor 51 is fixed on the displacement sensor seat 52. According to a specific example of the present invention, two test elements 5 are arranged circumferentially on the same axial section, and the circumferential angle between the two test elements 5 ranges from 30° to 150°, preferably from 60° to 120°.

[0038] According to a specific example of the present invention, the first axial section 61 and the second axial section 62 are respectively close to the low-pressure medium side and the high-pressure medium side, and two active control elements 41, two passive clamping elements 42 and two test elements 5 are respectively fixed on the two axial sections. Specifically, the first active control element 411, the second active control element 412, the first passive clamping element 421, the second passive clamping element 422, the first test element 511 and the second test element 512 are provided on the first axial section 61, and the third active control element 413, the fourth active control element 414, the third passive clamping element 423, the fourth passive clamping element 424, the third test element 513 and the fourth test element 514 are provided on the second axial section 62. On the first axial section, the first active regulating element 411 is arranged at an angle of 90° to the second active regulating element 412, the first passive clamping element 421 is arranged at an angle of 180° to the first active regulating element 411, and the second passive regulating element 422 is arranged at an angle of 180° to the second active regulating element 412. On the second axial section, the third active regulating element 413 is arranged at an angle of 90° to the fourth active regulating element 414, the third passive clamping element 423 is arranged at an angle of 180° to the third active regulating element 413, the fourth passive regulating element 424 is arranged at an angle of 180° to the fourth active regulating element 414, the third test element 513 is located between the third active regulating element 413 and the fourth active regulating element 414, and the fourth test element 514 is located between the fourth active regulating element 414 and the third passive clamping element 423.

[0039] According to a specific embodiment of the present invention, referring to Figure 6 The inner cylindrical surface 24 of the sealing stator is a hole-type damping sealing surface with evenly arranged holes.

[0040] Combination Figure 7 and Figure 8 The control and test of the axial center position of the sealing stator 2 in an axial section are described. As shown in the figure, the radius of the outer cylindrical surface 11 of the rotating shaft is r 1 , the radius of the inner cylindrical surface 22 of the sealing stator is r 2 , the radius of the outer cylindrical surface 23 of the sealing stator is r 3 , the radius of the inner cylindrical surface of the fixed shell 3 is r 4 The axis position of the rotating shaft 1 is O, the two contact points between the displacement sensor 41 and the outer cylindrical surface 23 of the sealed stator are A and B respectively, and the circumferential angle between the radius line OA and OB is 2θ. Figure 7 When the sealed stator 2 is in the concentric state with the rotating shaft 1 as shown, the axis center of the sealed stator 2 is also point O; the axis center position of the sealed stator 2 is changed by the active control element 42, when the sealed stator 2 is in the state as shown Figure 8When the seal stator 2 is not concentric with the rotating shaft 1, the axis center of the seal stator 2 is point P, and AP = BP = r 3 , and the distances between points A and B and the original axis point O are AO = a and BO = b respectively. The distance difference between AO and BO in the concentric and non-concentric states is ar 3 ,br 3 It can be measured by the displacement sensor 41, and then according to the known r 3 The values ​​of a and b can be obtained by using the values. With O as the origin, the x-axis passing through the origin and the control element 42 and the y-axis passing through the origin and perpendicular to the x-axis are used as coordinate axes to establish a coordinate system on the axial section. In the xoy coordinate system, the coordinates of point A are (-asinθ, acosθ) and the coordinates of point B are (bsinθ, bcosθ). With A as the center and r as the center, the coordinates of point A and B are (-asinθ, acosθ). 3 The circle 1 formed by the radius and the point B as the center, r 3 The circle 2 formed by the radius will form two intersection points, of which the intersection point closer to O is point P. The equation curves of circle 1 and circle 2 can be expressed as:

[0041] (x+a 1 sinθ) 2 +(ya 1 cosθ) 2 =r 3 2 (1)

[0042] (xb 1 sinθ) 2 +(yb 1 cosθ) 2 =r 3 2 (2)

[0043] By combining equations (1) and (2), we can obtain the coordinates of the intersection point P. 2 The equation curve of the inner cylindrical surface 24 of the sealed stator can be obtained by taking O as the center and r as the radius. 1 The equation curve of the shaft outer cylindrical surface 11 can be obtained by taking 2 as the radius. Since the sealing gap is the closed space enclosed by the sealing stator inner cylindrical surface 24 and the shaft outer cylindrical surface 11, the sealing gap values ​​at different circumferential angles can be obtained on this basis.

[0044] After obtaining the sealing gap value on a certain axial section, combined with Fig. 9 , Fig.10 and Fig.11To further illustrate the regulation and testing principles of the sealing gap shape. The axial distance between the first axial section 61 and the second axial section 62 is L. The three-dimensional coordinate system oxyz is established with the axis O of the rotating shaft fixed on the first axial section 61 as the origin and the axis line of the rotating shaft as the z-axis. First, the axial coordinates P of the sealing stator 2 at different axial positions are obtained according to the axis line equation of the sealing stator 2, and then the circular curves of the inner cylindrical surface 24 of the sealing stator and the outer cylindrical surface 11 of the rotating shaft are obtained with the center of the circle at point P and r2 as the radius and with the center of the circle at point O and r1 as the radius, and then the sealing gap values ​​at different axial positions and circumferential angles are obtained. When the sealing stator 2 is in a position such as Fig. 9 When the sealing stator 2 is in the concentric state with the rotating shaft 1 as shown, the sealing gap is equal in the circumferential and axial directions, that is, the sealing gap has nothing to do with the axial and circumferential positions; when the sealing stator 2 is in the state shown Fig.10 When the sealing stator 2 is not centered with the rotating shaft 1 as shown, the axis of the sealing stator 2 is parallel to the axis of the rotating shaft 1, and the sealing gap value is only related to the circumferential position but not to the axial position; when the sealing stator 2 is in the state of being misaligned with the rotating shaft 1 as shown Fig.11 As shown in the state of being skewed with respect to the rotating shaft 1, the axis centerline of the sealing stator 2 is not parallel to the axis centerline of the rotating shaft 1, and the sealing gap value is related to both the axial and circumferential positions.

[0045] Implementation Case 2

[0046] Reference Fig.12 The difference between it and implementation case one is that the passive clamping element 42 is a clamping screw, the first passive clamping element 471 and the first active regulating element 411 are arranged circumferentially at an interval of 180°, the second passive clamping element 472 and the second active regulating element 412 are arranged circumferentially at an interval of 180°, and the rest of the structure and principle are the same as those in implementation case one.

[0047] The contents described in the embodiments of this specification are merely an enumeration of implementation forms of the inventive concept. The protection scope of the present invention should not be deemed to be limited to the specific forms described in the embodiments. The protection scope of the present invention also extends to equivalent technical means that can be conceived by those skilled in the art based on the inventive concept.

Claims

1. A cylindrical gap sealing gap shape control structure, comprising a rotating shaft (1), a sealing stator (2) and a fixed housing (3), wherein the sealing stator (2) is located between the fixed housing (3) and the rotating shaft (1), a sealing gap is formed between an outer cylindrical surface (11) of the rotating shaft and an inner cylindrical surface (24) of the sealing stator, one axial side of the sealing stator (2) is a high-pressure medium side, and the other axial side is a low-pressure medium side, characterized in that: A regulating element and a testing element are provided on the first axial section (61) on the low-pressure medium side and the second axial section (62) on the high-pressure medium side of the fixed shell (3); the regulating element (4) comprises an active regulating element (41) and a passive pressing element (42) for driving the change of the axial center position of the sealing stator; the testing element (5) is used to test the axial center position of the sealing stator; the active regulating element (41), the passive pressing element (42) and the testing element (5) are all in contact with the outer cylindrical surface (23) of the sealing stator.

2. The cylindrical gap sealing gap shape control structure according to claim 1, characterized in that: Two active regulating elements (41), two passive pressing elements (42) and two testing elements (5) are fixed on the first axial section (61) and the second axial section (62) respectively; the first axial section (61) is provided with a first active regulating element (411), a second active regulating element (412), a first passive pressing element (421), a second passive pressing element (422), a first testing element (511) and a second testing element (512); the second axial section (62) is provided with a third active regulating element (413), a fourth active regulating element (414), a third passive pressing element (423), a fourth passive pressing element (424), a third testing element (513) and a fourth testing element (514).

3. The cylindrical gap sealing gap shape control structure according to claim 2, characterized in that: The first active regulating element (411) and the second active regulating element (412) are arranged at an angle of 90°, and the third active regulating element (413) and the fourth active regulating element (414) are also arranged at an angle of 90°.

4. The cylindrical gap sealing gap shape control structure according to claim 2, characterized in that: The first passive pressing element (421) and the first active regulating element (411), the second passive pressing element (422) and the second active regulating element (421), the third passive pressing element (423) and the third active regulating element (413), and the fourth passive pressing element (424) and the fourth active regulating element (414) are all arranged at an angle of 180°.

5. The cylindrical gap sealing gap shape control structure according to claim 2, characterized in that: The first test element (511) and the second test element (512) are arranged at a certain angle, and the third test element (513) and the fourth test element (514) are also arranged at a certain angle, and the certain angle is an arbitrary value other than 180°.

6. The cylindrical gap sealing gap shape control structure according to claim 1, characterized in that: The active regulating element (41) is an adjusting screw or a micrometer screw.

7. The cylindrical gap sealing gap shape control structure according to claim 1, characterized in that: The passive clamping element (42) is a pneumatic element, comprising a pressure cylinder body (45), a pneumatic joint (44), a piston push rod (43) and a third auxiliary sealing ring (46); the pressure cylinder body (45) is fixed on a fixed housing (3); the pneumatic joint (44) is fixed on the pressure cylinder body (45); a third auxiliary sealing ring (46) is provided between the piston push rod (43) and the pressure cylinder body (45); one end of the piston push rod (43) is in contact with an outer cylindrical surface (23) of a sealing stator; and the other end of the piston push rod (43) is located in the pressure cylinder body (45).

8. The cylindrical gap sealing gap shape control structure according to claim 1, characterized in that: The passive pressing element (42) is a tightening screw (47).

9. The cylindrical gap sealing gap shape control structure according to claim 1, characterized in that: The test element (5) comprises a displacement sensor (51) and a displacement sensor seat (52) fixed on a fixed housing.

10. The cylindrical gap sealing gap shape control structure according to claim 1, characterized in that: The inner cylindrical surface (24) of the sealing stator can be a smooth surface, a labyrinth sealing surface with annular grooves, or a hole-type damping sealing surface with evenly arranged holes.

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