Electric grinding device and grinding method for sealing surface of valve body

Abstract

The invention discloses an electric grinding device and a grinding method of a valve body sealing surface, belongs to the field of safety valve assembly / maintenance, and aims to solve the problem that most of existing valve body sealing surface grinding devices only grind a horizontal sealing surface. Comprising a grinding disc, a first transmission shaft, a ball chain type universal joint, a second transmission shaft, a supporting frame, a fixing plate and an electric magnetic seat drill, a supporting seat is connected with the supporting frame, and the second transmission shaft is rotationally matched with the supporting seat through a first bearing and rotationally matched with the supporting frame through a second bearing; the first transmission shaft is connected to the left end of the second transmission shaft through a ball chain type universal joint, the right end of the second transmission shaft is coaxially connected with the left end of the transmission sleeve, the transmission sleeve is in running fit with the fixing plate through a third bearing, the electric magnetic drill press is fixed to the fixing plate, and the output end of the electric magnetic drill press is coaxially connected with the right end of the transmission sleeve. The first transmission shaft is sleeved with the grinding disc. The grinding device is compact in structure, and can be used for grinding a horizontally-arranged sealing surface and a vertically-arranged sealing surface.

Description

Technical Field

[0001] This invention belongs to the field of safety valve assembly / repair, and particularly relates to an electric grinding device and a grinding method for valve body sealing surfaces. Background Technology

[0002] The main steam safety valve is a non-direct load automatic valve, consisting of a main valve, a primary pilot valve, and a secondary valve. When the internal medium pressure of the boiler, pressure vessel, or main steam pressure pipeline exceeds the set pressure of the primary pilot valve, the primary pilot valve automatically opens, causing the secondary valve and the main valve to open respectively, thereby releasing the pipeline pressure. When the internal medium pressure of the main steam pressure pipeline is less than the reseating pressure of the primary pilot valve, the primary pilot valve closes, causing the secondary valve and the main valve to close respectively. Therefore, this safety valve is used to protect high-pressure, high-flow-rate systems such as high-pressure vessels, supercritical units, and main steam pipelines, preventing dangerous accidents such as leakage and explosion due to overpressure.

[0003] The main steam safety valve has high sealing requirements (zero leakage), so the flatness and roughness of the main valve sealing surface are also high, which can only be achieved by grinding. Due to the structure of the main steam safety valve and the requirements of on-site installation, the sealing surface of the main valve body is at 90° to the ground. However, most of the existing valve body sealing surface grinding devices are only for grinding horizontal sealing surfaces. In addition, the internal cavity structure of the main valve body is compact and the internal operating space is limited, making manual grinding impossible. Summary of the Invention

[0004] The purpose of this invention is to provide an electric grinding device and a grinding method for valve body sealing surfaces, thereby solving the problem that existing valve body sealing surface grinding devices mostly only grind horizontal sealing surfaces. The technical solution adopted by this invention is as follows:

[0005] An electric grinding device is used to grind the sealing surface of a main steam safety valve. The valve body of the main steam safety valve is a three-way component. The left opening of the valve body is a medium inlet, the lower opening of the valve body is a medium outlet, and the right opening of the valve body is a valve stem mounting port. The medium inlet, the medium outlet, and the valve stem mounting port are connected through a valve cavity. A valve seat structure is provided at the right end of the medium inlet. The right end face of the valve seat structure is the sealing surface to be ground. The grinding device includes a grinding disc, a first drive shaft, a ball chain universal joint, a second drive shaft, a support frame, a fixed plate, and an electric magnetic drill. The support base is connected to the support frame. The second drive shaft is rotatably engaged with the support base through a first bearing, and the second drive shaft is rotatably engaged with the support frame through a second bearing. The first drive shaft is connected to the left end of the second drive shaft through a ball chain universal joint. The right end of the second drive shaft is coaxially connected to the left end of the transmission sleeve. The transmission sleeve is rotatably engaged with the fixed plate through a third bearing. The electric magnetic drill is fixed on the fixed plate. The output end of the electric magnetic drill is coaxially connected to the right end of the transmission sleeve. The grinding disc is sleeved on the first drive shaft.

[0006] The left end face of the grinding disc is the grinding surface. The left end of the grinding device is inserted into the valve cavity through the valve stem mounting port, and the grinding surface of the grinding disc abuts against the sealing surface. The support frame is matched with the stop of the valve stem mounting port, and the fixing plate is connected to the valve body flange.

[0007] Furthermore, the outer end face of the valve stem mounting port is provided with several valve cover screw holes around the circumference, the fixing plate is provided with several flange holes around the circumference, one end of several studs is connected to several valve cover screw holes in a corresponding manner, and the other end of several studs passes through several flange holes in a corresponding manner and is connected to several fastening nuts in a corresponding manner.

[0008] Furthermore, the support base is provided with a through first stepped hole, which is composed of a first shaft hole section, a first countersunk hole section, a second countersunk hole section, and a first threaded section coaxially connected from left to right. The diameters of the first shaft hole section, the first countersunk hole section, the second countersunk hole section, and the first threaded section increase sequentially. The first countersunk hole section and the second countersunk hole section are connected by an annular first shaft shoulder end face. The first locking nut is threadedly connected to the first threaded section. The first locking nut presses the outer ring of the first bearing against the first shaft shoulder end face. The diameter of the first countersunk hole section is larger than the outer diameter of the inner ring of the first bearing, and the diameter of the first shaft hole section is larger than the diameter of the second drive shaft.

[0009] Furthermore, the support frame is provided with a through second stepped hole, which consists of a second shaft hole section, a third countersunk hole section, a fourth countersunk hole section, and a second threaded section coaxially connected from left to right. The diameters of the second shaft hole section, the third countersunk hole section, the fourth countersunk hole section, and the second threaded section increase sequentially. The third countersunk hole section and the fourth countersunk hole section are connected by an annular second shaft shoulder end face. The second locking nut is threadedly connected to the second threaded section. The second locking nut presses the outer ring of the second bearing against the second shaft shoulder end face. The diameter of the third countersunk hole section is larger than the outer diameter of the inner ring of the second bearing, and the diameter of the second shaft hole section is larger than the diameter of the second drive shaft.

[0010] Furthermore, the fixing plate is provided with a through third stepped hole, which is composed of a third shaft hole section, a fifth countersunk hole section, a sixth countersunk hole section, and a third threaded section coaxially connected from left to right. The diameters of the third shaft hole section, the fifth countersunk hole section, the sixth countersunk hole section, and the third threaded section increase sequentially. The fifth countersunk hole section and the sixth countersunk hole section are connected by an annular third shaft shoulder end face. The second locking nut is threadedly connected to the second threaded section. The second locking nut presses the outer ring of the second bearing against the second shaft shoulder end face. The diameter of the third countersunk hole section is larger than the outer diameter of the inner ring of the second bearing, and the diameter of the second shaft hole section is larger than the diameter of the second drive shaft.

[0011] Furthermore, the first drive shaft consists of a first shaft segment and a second shaft segment connected coaxially to the left and right. The outer diameter of the first shaft segment is smaller than that of the second shaft segment. The grinding disc is fitted onto the first shaft segment, and the tensioning screw is threadedly connected to the first shaft segment. The tensioning screw presses the grinding disc onto the left end face of the second shaft segment through a washer.

[0012] Furthermore, the transmission sleeve is a circular sleeve-shaped component with the right end sealed. An elongated hole is provided on the tube wall of the transmission sleeve along the axial direction. The left end of the transmission sleeve is inserted into and slidably fitted with the right end of the second transmission shaft. A fixing pin is provided on the second transmission shaft, which passes through the elongated hole. A spring is provided between the right end wall of the transmission sleeve and the right end face of the second transmission shaft.

[0013] Furthermore, if we set the spring deformation as H when the grinding disc presses against the sealing surface for grinding, then the grinding pressure P of the grinding disc is calculated using the following formula:

[0014] ;

[0015] In the formula, K is the stiffness of the spring, and D is the outer diameter of the sealing surface;

[0016] The grinding efficiency η is determined by the following formula:

[0017] ;

[0018] In the formula, a is an empirical constant, n is the pressure index, ranging from 0.7 to 1.0, V is the relative velocity, and m is the velocity index, ranging from 1.0 to 1.4.

[0019] Furthermore, the electric magnetic drill has a maximum electromagnetic attraction force of 11000N, a stroke of 250mm, a rated voltage of 220V, and a rated frequency of 50-60Hz.

[0020] The present invention also provides a method for grinding the sealing surface of a valve body, which is implemented using the aforementioned electric grinding device, and includes the following steps:

[0021] Step 1: Attach the electric magnetic drill to the fixed plate and mate the output end of the electric magnetic drill with the transmission sleeve;

[0022] Step 2: Adjust the angle of the grinding disc using a ball chain universal joint to ensure that the grinding surface of the grinding disc is in close contact with the sealing surface of the valve body;

[0023] Step 3: Turn on the electric magnetic drill and set its speed to 500r / min-680r / min. The rotation of the electric magnetic drill will drive the grinding disc to rotate, thereby achieving the grinding of the sealing surface.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] When the electric magnetic drill is turned on, it drives the grinding disc to rotate sequentially through the second drive shaft, the ball chain universal joint, and the first drive shaft. The grinding disc then grinds the sealing surface. This invention has a compact structure, which can effectively ensure the roughness and flatness of the sealing surface of the main steam safety valve body. It also has high grinding efficiency, is easy to operate, and has high safety. At the same time, it has a certain degree of versatility among similar products and can grind both horizontally and vertically set sealing surfaces. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the device for grinding the sealing surface of the valve body in this invention;

[0027] Figure 2 This is a sectional view of the support base;

[0028] Figure 3 It is a half-section view of the support frame;

[0029] Figure 4 This is a half-section view of the fixing plate;

[0030] Figure 5 This is a sectional view of the first drive shaft;

[0031] Figure 6 This is a sectional view of the transmission sleeve;

[0032] Figure 7 This is a sectional view of the valve body.

[0033] In the diagram, 1. Valve body, 2. Grinding disc, 3. Washer, 4. Tensioner screw, 5. First drive shaft, 6. Ball chain universal joint, 7. Second drive shaft, 8. First bearing, 9. First lock nut, 10. Support frame, 11. Second bearing, 12. Second lock nut, 13. Fixing pin, 14. Drive sleeve, 15. Spring, 16. Fixing plate, 17. Third bearing, 18. Third lock nut, 19. Electric magnetic drill, 20. Fastening nut, 21. Stud, 22. Support base, 23. Second shaft hole section, 24. First countersunk hole section, 25. Second... 26. Countersunk section, 27. First threaded section, 28. Second shaft hole section, 29. Third countersunk section, 30. Fourth countersunk section, 31. Second threaded section, 32. Third shaft hole section, 33. Fifth countersunk section, 34. Sixth countersunk section, 35. Third threaded section, 36. Flange hole, 37. First shaft section, 38. Second shaft section, 39. Oblong hole, 40. Medium inlet, 41. Valve cavity, 42. Valve stem mounting port, 43. Medium outlet, 44. Valve cover screw hole, 45. Sealing surface, 46. First shaft shoulder end face, 47. Second shaft shoulder end face, 48. Third shaft shoulder end face. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0035] The connections mentioned in this invention are divided into fixed connections and detachable connections. Fixed connections, also known as non-detachable connections, include but are not limited to conventional fixed connection methods such as folded connections, riveted connections, adhesive connections, and welded connections. Detachable connections include but are not limited to conventional disassembly methods such as bolted connections, snap-fit ​​connections, pin connections, and hinged connections. When a specific connection method is not explicitly defined, it is assumed that at least one existing connection method can be found to achieve this function, and those skilled in the art can choose according to their needs. For example, a welded connection can be chosen for fixed connections, and a bolted connection can be chosen for detachable connections.

[0036] The present invention will be further described in detail below with reference to the accompanying drawings. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0037] Example 1: As Figures 1-7 As shown, an electric grinding device is used to grind the sealing surface 44 of a main steam safety valve. The valve body 1 of the main steam safety valve is a three-way component. The left opening of the valve body 1 is a medium inlet 39, the lower opening of the valve body 1 is a medium outlet 42, and the right opening of the valve body 1 is a valve stem mounting port 41. The medium inlet 39, the medium outlet 42, and the valve stem mounting port 41 are connected through a valve cavity 40. A valve seat structure is provided at the right end of the medium inlet 39, and the right end face of the valve seat structure is the sealing surface 44 to be ground. The grinding device includes a grinding disc 2, a first drive shaft 5, a ball chain universal joint 6, a second drive shaft 7, a support frame 10, and a fixing plate 1. 6 and electric magnetic drill 19, support base 22 is connected to support frame 10, second drive shaft 7 is rotatably engaged with support base 22 through first bearing 8, and second drive shaft 7 is rotatably engaged with support frame 10 through second bearing 11, first drive shaft 5 is connected to the left end of second drive shaft 7 through ball chain universal joint 6, right end of second drive shaft 7 is coaxially connected to the left end of drive sleeve 14, drive sleeve 14 is rotatably engaged with fixed plate 16 through third bearing 17, electric magnetic drill 19 is fixed on fixed plate 16, output end of electric magnetic drill 19 is coaxially connected to the right end of drive sleeve 14, grinding disc 2 is sleeved on first drive shaft 5;

[0038] The left end face of the grinding disc 2 is the grinding surface. The left end of the grinding device is inserted into the valve cavity 40 through the valve stem mounting port 41, and the grinding surface of the grinding disc 2 abuts against the sealing surface 44. The support frame 10 is matched with the stop of the valve stem mounting port 41, and the fixing plate 16 is connected to the flange of the valve body 1, thus completing the installation of the present invention.

[0039] When the electric magnetic drill 19 is turned on, it drives the grinding disc 2 to rotate sequentially through the second drive shaft 7, the ball chain universal joint 6, and the first drive shaft 5. The grinding disc 2 then grinds the sealing surface. This invention has a compact structure and can effectively ensure the roughness and flatness of the sealing surface of the main steam safety valve body 1. It also has high grinding efficiency, is easy to operate, and has high safety. At the same time, it has a certain degree of versatility among similar products and can grind both horizontally and vertically set sealing surfaces.

[0040] The outer end face of the valve stem mounting port 41 is provided with a plurality of valve cover screw holes 43 around its circumference. The fixing plate 16 is provided with a plurality of flange holes 35 around its circumference. One end of a plurality of studs 21 is connected to a plurality of valve cover screw holes 43, and the other end of a plurality of studs 21 passes through a plurality of flange holes 35 and is connected to a plurality of fastening nuts 20. The present invention fixes the valve body 1 to the fixing plate 16, thereby improving the stability of grinding.

[0041] The support base 22 is provided with a through first stepped hole, which is composed of a first shaft hole section 23, a first countersunk hole section 24, a second countersunk hole section 25 and a first threaded section 26 connected coaxially from left to right. The diameters of the first shaft hole section 23, the first countersunk hole section 24, the second countersunk hole section 25 and the first threaded section 26 increase sequentially. The first countersunk hole section 24 and the second countersunk hole section 25 are connected by an annular first shaft shoulder end face 45. The first locking nut 9 is threadedly connected to the first threaded section 26. The first locking nut 9 presses the outer ring of the first bearing 8 onto the first shaft shoulder end face 45. The diameter of the first countersunk hole section 24 is larger than the outer diameter of the inner ring of the first bearing 8. The diameter of the first shaft hole section 23 is larger than the diameter of the second drive shaft 7. The second drive shaft 7 passes through the first shaft hole section 23.

[0042] The support frame 10 is provided with a through second stepped hole, which is composed of a second shaft hole section 27, a third countersunk hole section 28, a fourth countersunk hole section 29 and a second threaded section 30 connected coaxially from left to right. The diameters of the second shaft hole section 27, the third countersunk hole section 28, the fourth countersunk hole section 29 and the second threaded section 30 increase sequentially. The third countersunk hole section 28 and the fourth countersunk hole section 29 are connected by an annular second shaft shoulder end face 46. The second locking nut 12 is threadedly connected to the second threaded section 30. The second locking nut 12 presses the outer ring of the second bearing 11 onto the second shaft shoulder end face 46. The diameter of the third countersunk hole section 28 is larger than the outer diameter of the inner ring of the second bearing 11. The diameter of the second shaft hole section 27 is larger than the diameter of the second drive shaft 7. The second drive shaft 7 passes through the first shaft hole section 23.

[0043] The fixed plate 16 is provided with a through third stepped hole, which is composed of a third shaft hole section 31, a fifth countersunk hole section 32, a sixth countersunk hole section 33 and a third threaded section 34 connected coaxially from left to right. The diameters of the third shaft hole section 31, the fifth countersunk hole section 32, the sixth countersunk hole section 33 and the third threaded section 34 increase sequentially. The fifth countersunk hole section 32 and the sixth countersunk hole section 33 are connected by an annular third shaft shoulder end face 47. The second locking nut 12 is threadedly connected to the second threaded section 30. The second locking nut 12 presses the outer ring of the second bearing 11 onto the second shaft shoulder end face 46. The diameter of the third countersunk hole section 28 is larger than the outer diameter of the inner ring of the second bearing 11. The diameter of the second shaft hole section 27 is larger than the diameter of the second drive shaft 7. The second drive shaft 7 passes through the first shaft hole section 23.

[0044] The first drive shaft 5 consists of a first shaft section 36 and a second shaft section 37 connected coaxially to the left and right. The outer diameter of the first shaft section 36 is smaller than the outer diameter of the second shaft section 37. The grinding disc 2 is sleeved on the first shaft section 36. The tension screw 4 is threadedly connected to the first shaft section 36. The tension screw 4 presses the grinding disc 2 against the left end face of the second shaft section 37 through the washer 3.

[0045] The transmission sleeve 14 is a circular sleeve-shaped component with the right end sealed. An elongated hole 38 is provided on the tube wall of the transmission sleeve 14 along the axial direction. The left end of the transmission sleeve 14 is inserted and slidably engaged with the right end of the second transmission shaft 7. A fixing pin 13 is provided on the second transmission shaft 7. The fixing pin 13 passes through the elongated hole 38. A spring 15 is provided between the right end wall of the transmission sleeve 14 and the right end face of the second transmission shaft 7.

[0046] When the grinding disc 2 is pressed against the sealing surface 44 for grinding, the deformation of the spring 15 is H. Then the grinding pressure P of the grinding disc 2 is calculated by the following formula:

[0047] ;

[0048] In the formula, K is the stiffness of spring 15, and D is the outer diameter of sealing surface 44;

[0049] The grinding efficiency η is determined by the following formula:

[0050] ;

[0051] In the formula, a is an empirical constant, n is the pressure index, ranging from 0.7 to 1.0, V is the relative velocity, and m is the velocity index, ranging from 1.0 to 1.4.

[0052] The electric magnetic drill 19 can apply leftward pressure to the transmission sleeve 14, and the spring 15 will then transmit the pressure to the grinding disc 2, so that the grinding disc 2 can press against the sealing surface 44. The elastic deformation of the spring 15 is proportional to the grinding pressure of the grinding disc 2. The grinding efficiency of the grinding disc 2 can be adjusted by the deformation of the spring 15.

[0053] The maximum electromagnetic attraction force of the electric magnetic base drill 19 is 11000N, the stroke is 250mm, the rated voltage is 220V, and the rated frequency is 50-60Hz.

[0054] Example 2: Figure 1 As shown, a method for grinding the sealing surface of a valve body, implemented using an electric grinding device as described in Embodiment 1, includes the following steps:

[0055] Step 1: Attach the electric magnetic drill 19 to the fixed plate 16 and mate the output end of the electric magnetic drill 19 with the transmission sleeve 14.

[0056] Step 2: Adjust the angle of the grinding disc 2 using the ball chain universal joint 6 so that the grinding surface of the grinding disc 2 is in close contact with the sealing surface 44 of the valve body 1.

[0057] Step 3: Turn on the electric magnetic drill 19 and set the rotation speed of the electric magnetic drill 19 to 500r / min-680r / min. The rotation of the electric magnetic drill 19 drives the grinding disc 2 to rotate, thereby achieving the grinding of the sealing surface 44.

[0058] The above embodiments are merely illustrative examples of the present invention and do not limit its scope of protection. Those skilled in the art can make partial changes to them, as long as they do not exceed the spirit and essence of the present invention, they are all within the scope of protection of the present invention.

Claims

1. An electric grinding device for grinding the sealing surface (44) of a main steam safety valve, wherein the valve body (1) of the main steam safety valve is a three-way component, the left opening of the valve body (1) is a medium inlet (39), the lower opening of the valve body (1) is a medium outlet (42), and the right opening of the valve body (1) is a valve stem mounting port (41). The medium inlet (39), the medium outlet (42) and the valve stem mounting port (41) are connected through a valve cavity (40). A valve seat structure is provided at the right end of the medium inlet (39), and the right end face of the valve seat structure is the sealing surface (44) to be ground. The device is characterized in that: The grinding device includes a grinding disc (2), a first drive shaft (5), a ball chain universal joint (6), a second drive shaft (7), a support frame (10), a fixed plate (16), and an electric magnetic drill (19). The support base (22) is connected to the support frame (10). The second drive shaft (7) and the support base (22) are rotatably connected through the first bearing (8), and the second drive shaft (7) and the support frame (10) are rotatably connected through the second bearing (11). The first drive shaft (5) is connected to the left end of the second drive shaft (7) through the ball chain universal joint (6). The right end of the second drive shaft (7) is coaxially connected to the left end of the transmission sleeve (14). The transmission sleeve (14) and the fixed plate (16) are rotatably connected through the third bearing (17). The electric magnetic drill (19) is fixed on the fixed plate (16). The output end of the electric magnetic drill (19) is coaxially connected to the right end of the transmission sleeve (14). The grinding disc (2) is sleeved on the first drive shaft (5). The left end face of the grinding disc (2) is the grinding surface. The left end of the grinding device is inserted into the valve cavity (40) through the valve stem mounting port (41), and the grinding surface of the grinding disc (2) abuts against the sealing surface (44). The support frame (10) is matched with the stop of the valve stem mounting port (41), and the fixing plate (16) is connected to the flange of the valve body (1).

2. The electric grinding device according to claim 1, characterized in that: The outer end face of the valve stem mounting port (41) is provided with a number of valve cover screw holes (43) around the circumference. The fixing plate (16) is provided with a number of flange holes (35) around the circumference. One end of a number of studs (21) is connected to a number of valve cover screw holes (43) in a corresponding manner. The other end of a number of studs (21) passes through a number of flange holes (35) in a corresponding manner and is connected to a number of fastening nuts (20) in a corresponding manner.

3. The electric grinding device according to claim 1, characterized in that: The support base (22) is provided with a through first stepped hole. The first stepped hole is composed of a first shaft hole section (23), a first countersunk hole section (24), a second countersunk hole section (25), and a first threaded section (26) connected coaxially from left to right. The diameters of the first shaft hole section (23), the first countersunk hole section (24), the second countersunk hole section (25), and the first threaded section (26) increase sequentially. The first countersunk hole section (24) and the second countersunk hole section (25) are connected by an annular first shaft shoulder end face (45). The first locking nut (9) is threadedly connected to the first threaded section (26). The first locking nut (9) presses the outer ring of the first bearing (8) onto the first shaft shoulder end face (45). The diameter of the first countersunk hole section (24) is greater than the outer diameter of the inner ring of the first bearing (8), and the diameter of the first shaft hole section (23) is greater than the diameter of the second drive shaft (7).

4. The electric grinding device according to claim 1, characterized in that: The support frame (10) is provided with a through second stepped hole. The second stepped hole is composed of a second shaft hole section (27), a third countersunk hole section (28), a fourth countersunk hole section (29), and a second threaded section (30) connected coaxially from left to right. The diameters of the second shaft hole section (27), the third countersunk hole section (28), the fourth countersunk hole section (29), and the second threaded section (30) increase sequentially. The third countersunk hole section (28) and the fourth countersunk hole section (29) are connected by an annular second shaft shoulder end face (46). The second locking nut (12) is threadedly connected to the second threaded section (30). The second locking nut (12) presses the outer ring of the second bearing (11) onto the second shaft shoulder end face (46). The diameter of the third countersunk hole section (28) is greater than the outer diameter of the inner ring of the second bearing (11), and the diameter of the second shaft hole section (27) is greater than the diameter of the second drive shaft (7).

5. The electric grinding device according to claim 1, characterized in that: The fixed plate (16) is provided with a through third stepped hole. The third stepped hole is composed of a third shaft hole section (31), a fifth countersunk hole section (32), a sixth countersunk hole section (33) and a third threaded section (34) connected coaxially from left to right. The diameters of the third shaft hole section (31), the fifth countersunk hole section (32), the sixth countersunk hole section (33) and the third threaded section (34) increase sequentially. The fifth countersunk hole section (32) and the sixth countersunk hole section (33) are connected through an annular third shaft shoulder end face (47). The second locking nut (12) is threadedly connected to the second threaded section (30). The second locking nut (12) presses the outer ring of the second bearing (11) onto the second shaft shoulder end face (46). The diameter of the third countersunk hole section (28) is greater than the outer diameter of the inner ring of the second bearing (11). The diameter of the second shaft hole section (27) is greater than the diameter of the second drive shaft (7).

6. The electric grinding device according to claim 1, characterized in that: The first drive shaft (5) consists of a first shaft section (36) and a second shaft section (37) connected coaxially on the left and right sides. The outer diameter of the first shaft section (36) is smaller than the outer diameter of the second shaft section (37). The grinding disc (2) is fitted onto the first shaft section (36). The tightening screw (4) is threadedly connected to the first shaft section (36). The tightening screw (4) presses the grinding disc (2) onto the left end face of the second shaft section (37) through the washer (3).

7. The electric grinding device according to claim 1, characterized in that: The transmission sleeve (14) is a circular sleeve-shaped component with the right end sealed. An elongated hole (38) is provided on the tube wall of the transmission sleeve (14) along the axial direction. The left end of the transmission sleeve (14) is inserted and slidably fitted with the right end of the second transmission shaft (7). A fixing pin (13) is provided on the second transmission shaft (7). The fixing pin (13) passes through the elongated hole (38). A spring (15) is provided between the right end wall of the transmission sleeve (14) and the right end face of the second transmission shaft (7).

8. The electric grinding device according to claim 1, characterized in that: When the grinding disc (2) is pressed against the sealing surface (44) for grinding, the deformation of the spring (15) is H. Then the grinding pressure P of the grinding disc (2) is calculated by the following formula: ； In the formula, K is the stiffness of the spring (15), and D is the outer diameter of the sealing surface (44); The grinding efficiency η is determined by the following formula: ； In the formula, a is an empirical constant, n is the pressure index, ranging from 0.7 to 1.0, V is the relative velocity, and m is the velocity index, ranging from 1.0 to 1.

4.

9. The electric grinding device according to claim 1, characterized in that: The maximum electromagnetic attraction force of the electric magnetic base drill (19) is 11000N, the stroke is 250mm, the rated voltage is 220V, and the rated frequency is 50-60Hz.

10. A method for grinding the sealing surface of a valve body, implemented using an electric grinding device according to any one of claims 1-9, characterized in that, Includes the following steps: Step 1: Attach the electric magnetic drill (19) to the fixed plate (16) and mate the output end of the electric magnetic drill (19) with the transmission sleeve (14); Step 2: Adjust the angle of the grinding disc (2) by using the ball chain universal joint (6) so that the grinding surface of the grinding disc (2) is in close contact with the sealing surface (44) of the valve body (1); Step 3: Turn on the electric magnetic drill (19) and set the speed of the electric magnetic drill (19) to 500r / min-680r / min. The electric magnetic drill (19) rotates to drive the grinding disc (2) to rotate, thereby achieving the grinding of the sealing surface (44).

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