A new type of integrated seamless high-temperature and high-pressure gate valve and its valve body processing technology

Abstract

The present invention discloses a novel integrated high-temperature and high-pressure gate valve without weld seams and a processing technology for its valve body. Among them, the high-temperature and high-pressure gate valve includes: a valve body, including a valve body with a fluid passage arranged inside, a valve seat integrally formed in the valve body, a valve cover arranged on the valve body, and a valve plate for blocking the fluid passage; a transmission mechanism, including a ball screw with one end passing through the valve cover and connected to the valve plate, and a valve rod stopper arranged on the ball screw. By obliquely arranging the position indicator on the valve cover and the position indicator being perpendicular to the valve rod stopper, the present invention can effectively prevent impurities from entering. And because the position indicator is perpendicularly arranged with the valve rod stopper, the force on the ball head in the position indicator always acts along the movement direction, the guiding force is more uniform, and the wear is also uniform, solving serious faults such as over-stress deformation and breakage of the ball head in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of gate valves, and particularly to a new type of integrated seamless high-temperature and high-pressure gate valve and its valve body processing technology. Background Art

[0002] Regarding the "position indicator thrust rod jamming" fault, the macroscopic manifestation is that the valve moves beyond the position, and the signal feedback of the position indicator is significantly delayed. The reasons for the fault are as follows: 1) There are impurities / wear between the graphite sleeve and the thrust rod. Due to insufficient spring thrust, the thrust rod rebounds slowly, resulting in a delayed response; 2) The cooperation between the thrust rod and the valve stem block is misaligned, that is, the slope of the block is relatively large (usually 15-20°). At the end of the valve operation, the sensitivity of the position indicator is too high. After multiple operations, when there is wear between the thrust rod and the valve stem block, structural interference occurs, resulting in deformation of the thrust rod, leading to thrust rod jamming, and even the valve closing / opening too much, causing serious faults such as over-stress deformation and breakage of the ball head. Summary of the Invention

[0003] The purpose of the present invention is to solve the above deficiencies and provide a new type of integrated seamless high-temperature and high-pressure gate valve and its valve body processing technology.

[0004] To solve the above technical problems, the present invention adopts the following technical solutions: A new type of integrated seamless high-temperature and high-pressure gate valve, comprising:

[0005] A valve body, including a valve body with a fluid passage inside, a valve seat integrally formed in the valve body, a valve cover provided on the valve body, and a valve plate for blocking the fluid passage;

[0006] A transmission mechanism, including a ball screw with one end passing through the valve cover and connected to the valve plate, and a valve stem block provided on the ball screw;

[0007] A fully enclosed electric mechanism, provided on the valve cover and connected to the other end of the ball screw for driving the ball screw to move;

[0008] A position indicator, inclinedly provided on both sides of the valve cover, perpendicular to the valve stem block and cooperating with the valve stem block.

[0009] Further, the position indicator includes a pressure-bearing housing provided on the valve cover, a push rod with a ball head at one end and cooperating with the valve stem block. The pressure-bearing housing includes a first housing for setting a ceramic piezoelectric sheet and a second housing with an inner cavity larger than the first housing. The other end of the push rod passes through the second housing and extends into the first housing. A ceramic piezoelectric sheet is provided outside the side wall of the first housing away from the second housing, and a temperature measuring point is provided on the first housing.

[0010] Further, a ball guide sleeve sleeving on the push rod is connected to the mortise and tenon groove on the second housing and fixed by screws.

[0011] Further, a baffle is arranged on a section of the push rod located inside the second housing, and a spring is arranged between the baffle and the connection between the first housing and the second housing.

[0012] Further, the measuring method of the position indicator is as follows:

[0013] Displacement = k / v×(1 + αΔT);

[0014] Where: the displacement is the measured displacement;

[0015] v is the peak voltage of the third echo generated by the ceramic piezoelectric sheet;

[0016] k is the piezoelectric coefficient, representing the relationship between displacement and voltage;

[0017] α is the temperature coefficient, representing the influence of temperature change on displacement;

[0018] ΔT is the temperature change.

[0019] Further, the outside of the valve stem stopper is provided with a first inclined surface and a second inclined surface that are symmetric up and down, and the connection between the first inclined surface and the second inclined surface is provided with a spherical chamfer.

[0020] Further, the push rods on both sides are respectively perpendicular to the first inclined surface and the second inclined surface.

[0021] Further, the included angle between the first inclined surface and the vertical direction is A, and the included angle A is calculated by the following method:

[0022] ;

[0023] Where: r1 is half of the inner diameter of the valve cover minus 3 mm;

[0024] r2 is the radius of the valve stem;

[0025] d is the maximum theoretical linear running distance of the gate valve with a diameter of d;

[0026] d 误差 is the error of the maximum theoretical linear running distance of the gate valve, which is ±0.5 mm;

[0027] 1 is half of the arc chord length of the spherical chamfer section plane.

[0028] A valve body processing technology for processing the above-mentioned new type of integrated seamless high-temperature and high-pressure gate valve includes the following steps:

[0029] S1. Subtractive machining: Machine the outer shape and internal structure of the valve body. Based on the design drawing, reduce the thickness of the sealing surface by 5 ± 0.1 mm and increase the thickness of the fluid passage by 1.2 mm to machine the basic structures of the valve body and valve seat.

[0030] S2. Additive machining: Laser cladding of the sealing surface with cobalt-based alloy. The sealing surface includes the inlet sealing surface and the outlet sealing surface. First machine the outlet sealing surface and then the inlet sealing surface. The two machining processes are the same.

[0031] S3. Precision machining: Precision machine the valve body after laser cladding according to the standard dimensions of the design drawing.

[0032] S4. Surface inspection and cleaning: Inspect the surface of the valve body after precision machining, process the cracked parts and re-perform cladding until no cracks appear. Clean the valve body using an ultrasonic cleaning machine to ensure that the surface is free of impurities, oil stains, and particulate foreign matters.

[0033] S5. Electrical discharge surface machining: Machine the valve seat sealing surface to ensure that the surface roughness meets the sealing requirements.

[0034] S6. Hydrostatic test: Install the valve plate in the valve body, simulate the motor through the ejector rod to ensure that the sealing force between the valve plate and the valve seat meets the design requirements. Fill the valve inlet with water and pressurize it to 1.2 times the design pressure of the valve, and check the leakage at the valve outlet. If there is leakage, repeat S5.

[0035] Furthermore, in step S2, the steps for machining the sealing surface are as follows:

[0036] S21. Place the valve body to be machined in the workpiece heater, with the inlet end on a 5° inclined plane, and adjust the angle of the outlet sealing surface through a feeler gauge to make the outlet sealing surface horizontal ± 0.05°.

[0037] S22. Set the heating temperature of the workpiece heater to 180 °C and set the insulation range to ± 10 °C. Take five temperature points on the inner wall of the valve body, and the temperature difference between the highest and lowest temperatures is less than 5 °C.

[0038] S23. Since the position will shift during the heating process, check whether the angles of the outlet sealing surface and the inlet sealing surface meet the requirements.

[0039] S24. Push the laser head of the two-axis powder spraying type laser cladding machine downward from the middle flange of the valve body, use a square light spot with a size of 0.5 * 0.5 mm, set the cladding thickness to 3 mm, and machine in the way from the inside to the outside and from left to right. When machining near the edge of the fluid passage, adjust the cladding power until it is far from the edge of the fluid passage.

[0040] S25. After the cladding is completed, keep the valve body temperature of the workpiece heater at 180 ± 10 °C, wait for 4 h, and cool it to room temperature after ensuring that the workpiece has no cracks;

[0041] S26. Remove the welding thermal stress. Set the temperature of the workpiece heater to 700 ± 30 °C for annealing, keep it warm for 5 h, and then linearly cool it to 200 °C. The cooling time is not less than 24 h;

[0042] S27. Remove the outermost layer during the cladding process and check whether there are cracks in the cladding layer. If there are cracks, remove them together;

[0043] S28. Repeat S21 - S27 twice to ensure that the actual thickness of the cladding layer > 5 mm.

[0044] Further, in the S24 step, adjust the cladding power in the following way:

[0045] When the center of the light spot is processed to a distance < 1 mm from the edge of the fluid channel, reduce the power by 20%; when the center of the light spot is 0.5 mm away from the edge of the flow channel, stop the cladding. At this time, the laser head makes an idle stroke until the center of the light spot is 0.5 mm away from the edge of the fluid channel, and then start the laser head again. The starting power is 80% of the set power; when the center of the light spot is 1 mm away from the edge of the fluid channel, the feeding is adjusted to the set power.

[0046] Further, the specific operation of the S5 step is as follows:

[0047] S51. Design and manufacture of the electric discharge machining electrode: The electrode is the discharge body for machining the valve seat sealing surface. It is made of copper material. The tooling structure is the same as that of the valve plate, but the contact surface is the same as the valve seat surface, and the thickness is 0.1 mm less than that of the valve plate. The surface treatment of the valve seat and the guide rail on the valve seat can be carried out simultaneously;

[0048] S52. Install the valve body: Horizontally install the valve body on the electric discharge machining center, and install the valve body and the electric discharge machine with the central axis of the upper flange of the valve body as the center line;

[0049] S53. Set the roughness reference line: Set 10 reference lines on the cross-section of the upper flange of the valve body as the roughness reference lines, with 5 for the inlet sealing surface and 5 for the outlet sealing surface respectively. Set the roughness detection instrument and measure the average roughness of the 10 reference lines. The method of measuring the roughness is from the upper flange of the valve body downwards until the sealing surface contacts the valve body;

[0050] S54. Set the parameters of the electric discharge machining center: Set the discharge voltage to 80 V, the discharge current to 2 A, the pulse width to 10 μs, the pulse interval to 50 μs, the working gap to 20 μm, and the discharge frequency to 500 kHz;

[0051] S55, Adaptive Optimization of Machining Parameters: Since the stress and materials on the cladding surface are not completely consistent during the cladding process, fixed parameters cannot be used for machining. Instead, dynamic adjustment should be carried out in combination with the roughness measurement results.

[0052] Furthermore, in the above S55, the method of dynamic adjustment is as follows:

[0053] After every 15 minutes of machining, roughness detection is carried out. Comparing with the previous roughness, if there is no change in roughness, the discharge current is reduced by 0.1 A, and the roughness Ra(i) at this time is recorded, where i represents the i-th time after the roughness has not changed.

[0054] Furthermore, during the dynamic adjustment process, if the roughness still cannot meet the requirements after 3 times, the adjustment is carried out according to the following formula:

[0055] ln(Ra(i) / K) = M·ln(I(i)) - N·ln(d(i));

[0056] Where: Ra(i) is the average roughness recorded at the i-th time;

[0057] I(i) is the discharge current corresponding to the i-th record;

[0058] d(i) is the set working gap at the i-th record;

[0059] K is the roughness reference coefficient;

[0060] M is the current influence coefficient;

[0061] N is the gap influence coefficient;

[0062] By substituting the data of 3 groups or more (Ra(i), I(i), d(i)) into the above formula, the estimated values of the three parameters K, M, and N can be obtained; then, substituting the roughness Ra(i + 1) corresponding to the (i + 1)-th record, the working gap d(i + 1) set at the (i + 1)-th record, and the estimated values of K, M, and N into the following formula to obtain the recommended discharge current;

[0063] ;

[0064] Machine for 1 hour according to the recommended discharge current I(i + 1). If it still does not meet the requirements after 1 hour, repeat the above process.

[0065] Compared with the prior art, the present invention has the following beneficial effects:

[0066] 1. In the present invention, by obliquely arranging the position indicator on the valve cover and making the position indicator perpendicular to the valve stem stopper, it can effectively prevent impurities from entering. Moreover, since the position indicator is perpendicularly arranged with the valve stem stopper, the force on the ball head inside the position indicator is always along the movement direction, the guiding force is more uniform, and the wear is also uniform, solving the serious problems such as over-stress deformation and breakage of the ball head in the prior art.

[0067] 2. In the present invention, the valve stem stopper is set as a first inclined surface and a second inclined surface that are symmetric up and down. By setting the angle between the first inclined surface and the vertical direction as A, it can ensure full contact between the ball head inside the position indicator and the valve stem stopper. In addition, by setting a spherical chamfer between the first inclined surface and the second inclined surface, it is ensured that once the ball head enters in the reverse direction, the ball head will not get stuck in the middle of the valve stem stopper.

[0068] 3. In the present invention, through the integrated design of the valve body and the valve seat, first, the valve body has no pressure-bearing weld structure, avoiding the stress concentration and potential leakage risks caused by traditional welds, and significantly improving the safety and reliability of the valve under high-pressure working conditions; second, the interchangeability of the valve plates between gate valves of the same caliber is realized, without grinding, reducing the processing cost and maintenance cost; finally, through the optimized material removal and material addition processing technologies, combined with the precision electrical discharge machining method, the steps of multiple processing and adjustment in the traditional process are reduced, and the processing efficiency is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] The schematic diagrams in the specification forming a part of the present application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0070] Figure 1 is a schematic diagram of an embodiment of the present invention.

[0071] Figure 2 are the three-view drawings of the valve body of an embodiment of the present invention.

[0072] Figure 3 is a schematic diagram of the position indicator of an embodiment of the present invention.

[0073] Figure 4 is a partial schematic diagram of the valve stem stopper of an embodiment of the present invention.

[0074] In the figure: 1. Valve body; 11. Valve body; 12. Valve seat; 13. Valve cover; 14. Valve plate; 15. Fluid passage; 2. Transmission mechanism; 21. Ball screw; 22. Valve rod block; 3. Fully enclosed electric mechanism; 4. Position indicator; 41. Pressure-bearing housing; 42. Ball head; 43. Push rod; 44. Ceramic piezoelectric sheet; 411. First housing; 412. Second housing; 413. Temperature measurement point; 414. Ball guide sleeve; 46. Baffle; 45. Spring; 221. First inclined surface; 222. Second inclined surface. Specific embodiments

[0075] The following will combine the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0076] Please refer to Figures 1-4 。

[0077] The novel integrated seamless high-temperature and high-pressure gate valve of the present invention includes:

[0078] The valve body 1 includes a valve body 11 with a fluid passage 15 provided therein, a valve seat 12 integrally formed in the valve body 11, a valve cover 13 provided on the valve body 11, and a valve plate 14 for blocking the fluid passage 15;

[0079] The transmission mechanism 2 includes a ball screw 21 with one end passing through the valve cover 13 and connected to the valve plate 14, and a valve rod block 22 provided on the ball screw 21;

[0080] The fully enclosed electric mechanism 3 is provided on the valve cover 13 and connected to the other end of the ball screw 21 for driving the ball screw 21 to move;

[0081] The position indicator 4 is inclinedly provided on both sides of the valve cover 13, perpendicular to the valve rod block 22 and cooperating with the valve rod block 22.

[0082] By setting the position indicator 4 to be inclined, perpendicular to the valve rod block 22 and cooperating with the valve rod block 22, since the main impurities fall from the upper part, the oblique guidance is less likely to introduce impurities. And through the design that the position indicator 4 is perpendicular to the valve rod block 22, the ball head 42 is perpendicular to the valve rod block 22, and the force on the ball head 42 is always along the movement direction, so that the guiding force is more uniform and the wear is also more uniform.

[0083] Preferably, the position indicator 4 is a high-temperature and high-pressure linear position indicator 4. The high-temperature and high-pressure linear position indicator 4 uses the method of ultrasonic micrometer and has built-in temperature compensation, being less affected by temperature. Meanwhile, the method of ultrasonic displacement measurement has a fault self-checking function. When a fault of the position indicator 4 is detected during self-checking, the valve action will be restricted, basically eliminating the occurrence of fracture faults.

[0084] In one embodiment, the position indicator 4 includes a pressure-bearing housing 41 arranged on the valve cover 13, a push rod 43 with a ball head 42 at one end and cooperating with the valve rod stopper 22. The pressure-bearing housing 41 includes a first housing 411 for arranging a ceramic piezoelectric sheet 44 and a second housing 412 with an inner cavity larger than the first housing 411. The other end of the push rod 43 passes through the second housing 412 and extends into the first housing 411. A ceramic piezoelectric sheet 44 is arranged outside the side wall of the first housing 411 away from the second housing 412, and a temperature measurement point 413 is arranged on the first housing 411. With such a design, by improving the structure of the position indicator 4, and the push rod 43 and the ball head 42 on the position indicator 4 are perpendicular to the valve stopper, ensuring non-separation throughout the valve action process, avoiding knocking and extrusion, and achieving a full-range measurement of the opening of the electric gate valve.

[0085] In one embodiment, a ball bearing guide sleeve 414 sleeved on the push rod 43 is connected to the second housing 412 by a tenon groove connection and fixed by screws. With such a design, by replacing the sliding guide sleeve with the ball bearing guide sleeve 414, the friction force during the action process is greatly reduced, the wear amount is reduced, and the jamming caused by wear is avoided.

[0086] In one embodiment, a baffle 46 is arranged on a section of the push rod 43 inside the second housing 412, and a spring 45 is arranged between the baffle 46 and the connection between the first housing 411 and the second housing 412. With such a design, it is convenient for the movement and reset of the push rod 43 and the ball head 42.

[0087] In one embodiment, the measurement method of the position indicator 4 is as follows:

[0088] Displacement = k / v × (1 + αΔT);

[0089] Where: Displacement is the measured displacement;

[0090] v is the peak voltage of the third echo generated by the ceramic piezoelectric sheet 44;

[0091] k is the piezoelectric coefficient, representing the relationship between displacement and voltage;

[0092] α is the temperature coefficient, representing the influence of temperature change on displacement;

[0093] ΔT is the temperature change. With such a design, a non-contact displacement measurement method with temperature compensation is adopted. By means of the ceramic piezoelectric sheet 44 on the outer wall of the high-temperature and high-pressure pipe, the intensity of the third peak echo signal is measured, realizing the measurement of the valve opening under high-temperature and high-pressure conditions. At the same time, through the temperature measuring point 413 signal, the non-linear change of displacement measurement under high-temperature, medium-temperature, and normal-temperature conditions is compensated, improving the measurement accuracy to the order of 0.01 mm.

[0094] Preferably, the self-check formula of the position indicator 4 is as follows:

[0095] ;

[0096] where: displacement 测 is the displacement obtained by measurement;

[0097] displacement 预期 is the expected displacement;

[0098] frequency 实际 is the actual ultrasonic excitation frequency;

[0099] frequency 预期 is the expected ultrasonic excitation frequency. With such a design, through the change of the signal emission and reception frequencies of the ceramic piezoelectric sheet 44, the fault self-check of the position indicator 4 is realized, solving the problem that the traditional position indicator 4 cannot identify faults.

[0100] In one embodiment, the outside of the valve stem stopper 22 is provided with a first inclined surface 221 and a second inclined surface 222 that are symmetric up and down, and the connection between the first inclined surface 221 and the second inclined surface 222 is provided with a spherical chamfer. With such a design, in order to make the ball head 42 in full contact with the valve stopper, and to ensure that once the ball head 42 enters the reverse direction, the ball head 42 will not get stuck in the middle of the valve stopper, the connection between the first inclined surface 221 and the second inclined surface 222 is provided with a spherical chamfer.

[0101] Preferably, the spherical chamfer generally selects an R25 spherical chamfer, which is better. The width of 2 mm is the best. If it is less than 2 mm, it is difficult to make a sphere, and if it is greater than 2 mm, the size of the stopper is too large.

[0102] In one embodiment, the two push rods 43 on both sides are respectively perpendicular to the first inclined surface 221 and the second inclined surface 222. With such a design, by respectively arranging the push rods 43 on both sides, and the push rods 43 are respectively perpendicular to the first inclined surface 221 and the second inclined surface 222, the accuracy of the position indicator 4 detection can be ensured, and detection can be carried out during the use of the valve.

[0103] In one embodiment, the angle between the first inclined surface 221 and the vertical direction is A, and the angle A is calculated in the following way:

[0104] ;

[0105] Wherein: r1 is half of the inner diameter of the valve cover 13 minus 3 mm; after subtracting 3 mm from the inner diameter of the valve cover 13, the valve stem block 22 can move normally within the valve cover 13, and there will be no large gap between the valve stem block 22 and the valve cover 13;

[0106] r2 is the radius of the valve stem;

[0107] d is the maximum theoretical linear travel distance of a gate valve with a caliber of d;

[0108] d 误差 is the error of the maximum theoretical linear travel distance of the gate valve, which is ±0.5 mm;

[0109] 1 is half of the arc chord length of the spherical chamfer section. With such a design, through the above formula, the included angle A can be calculated according to valves of different calibers, thus facilitating the design of the valve block.

[0110] Taking a DN70 gate valve as an example, the maximum theoretical travel distance is 70 mm, r1 is 25 mm, r2 is 15 mm, and d 误差 is 1 mm. At this time, the included angle A is 8.2°.

[0111] A valve body processing technology for processing the above-mentioned new type of integrated seamless high-temperature and high-pressure gate valve includes the following steps:

[0112] S1. Subtractive machining: Machine the outer shape and internal structure of the valve body 11. Using a 5-axis numerical control machine tool, based on the design drawing, reduce the thickness of the sealing surface by 5 ± 0.1 mm and increase the thickness of the fluid passage 15 by 1.2 mm to machine the basic structures of the valve body 11 and the valve seat 12;

[0113] S2. Additive machining: Laser cladding of cobalt-based alloy on the sealing surface. First machine the outlet sealing surface, and then machine the inlet sealing surface. The two machining processes are the same; during cladding, slight deformation of other parts will inevitably occur. The slight deformation only affects the sealing surface. Since the outlet sealing surface plays a major sealing role, the inlet sealing surface is machined first and the outlet sealing surface is machined later. In this way, even if there is deformation, it affects the inlet sealing surface and has little impact on the outlet sealing surface;

[0114] S21. Place the valve body 11 to be machined in the workpiece heater, with the inlet end on a 5° inclined plane, and adjust the angle of the outlet sealing surface through a feeler gauge to make the outlet sealing surface horizontal ±0.05°;

[0115] S22. Set the heating temperature of the workpiece heater to 180 °C, and set the heat preservation range to ±10 °C. Take five temperature points on the inner wall temperature of the valve body 11, and the temperature difference between the highest and lowest temperatures is less than 5 °C;

[0116] S23. Since the heating process will cause position deviation, check whether the angles of the outlet sealing surface and the inlet sealing surface meet the requirements;

[0117] S24. Push the laser head of the two-axis powder spraying type laser cladding machine downward from the middle flange of the valve body 11. Use a square spot with a size of 0.5 * 0.5 mm, set the cladding thickness to 3 mm, and the surfacing method is to process from the inside to the outside and from left to right. When processing near the edge of the fluid passage 15, adjust the cladding power until it is far from the edge of the fluid passage 15; when the center of the spot is processed to a distance less than 1 mm from the edge of the fluid passage 15, reduce the power by 20%; when the center of the spot is 0.5 mm away from the edge of the flow passage, stop cladding. At this time, the laser head makes an idle stroke until the center of the spot is 0.5 mm away from the edge of the fluid passage 15, and then start the laser head again. The starting power is 80% of the set power; when the center of the spot is 1 mm away from the edge of the fluid passage 15, the feeding is adjusted to the set power;

[0118] S25. After cladding, keep the temperature of the valve body 11 of the workpiece heater at 180 ± 10 °C, wait for 4 h, and cool it to room temperature after ensuring that the workpiece has no cracks;

[0119] S26. Remove the welding thermal stress. Set the temperature of the workpiece heater to 700 ± 30 °C for annealing, keep warm for 5 h, and then linearly cool it to 200 °C. The cooling time is not less than 24 h;

[0120] S27. Remove the outermost layer during the cladding process, check whether there are cracks in the cladding layer. If there are cracks, remove them together;

[0121] S28. Repeat S21 - S27 twice to ensure that the actual thickness of the cladding layer > 5 mm;

[0122] S3. Finish machining: Use a 5-axis CNC machine tool to finish machine the valve body 11 after laser cladding according to the standard dimensions of the design drawing;

[0123] S4. Surface inspection and cleaning: Inspect the surface of the surfacing valve body 11 after finish machining, process the cracked parts and re-clad them until there are no cracks. Use an ultrasonic cleaning machine to clean the valve body 11 to ensure that the surface has no impurities, oil stains, and particulate foreign matters;

[0124] S5. Electric discharge surface machining: Machine the sealing surface of the valve seat 12 to ensure that the surface roughness of the sealing surface meets the sealing requirements.

[0125] S51. Design and Manufacture of Electric Discharge Electrode: The electrode is the discharge body for machining the sealing surface of the valve seat 12. It is made of copper material. The tooling structure is the same as that of the valve plate 14, but the contact surface is consistent with the surface of the valve seat 12, and its thickness is 0.1 mm less than that of the valve plate 14. The surface treatment of the valve seat 12 and the guide rail on the valve seat 12 can be carried out simultaneously;

[0126] S52. Install the valve body 11: Horizontally install the valve body 11 on the electric discharge machining center. Take the central axis of the upper flange of the valve body 11 as the center line to install the valve body 11 and the electric discharge motor;

[0127] S53. Set the roughness reference line: Set 10 reference lines on the cross-section of the upper flange of the valve body 11 as the roughness reference lines, with 5 for the inlet sealing surface and 5 for the outlet sealing surface respectively. Set the roughness detection instrument and measure the average roughness of the 10 reference lines. The roughness measurement method is from the upper flange of the valve body 11 downwards until the sealing surface contacts the valve body 11;

[0128] S54. Set the parameters of the electric discharge machining center: Set the discharge voltage to 80 V, the discharge current to 2 A, the pulse width to 10 μs, the pulse interval to 50 μs, the working gap to 20 μm, and the discharge frequency to 500 kHz;

[0129] S55. Adaptive Machining Parameter Optimization: Since the stress materials on the clad surface are not completely consistent during the cladding process, fixed parameters cannot be used for machining, but dynamic adjustment should be carried out in combination with the roughness measurement results; After machining for 15 minutes, conduct roughness detection, compare with the previous roughness. If the roughness does not change, reduce the discharge current by 0.1 A, and record the roughness Ra(i) at this time, where i represents the i-th time after the roughness does not change;

[0130] S6. Closed Water Test: Install the valve plate 14 in the valve body 11, simulate the motor through the ejector rod to ensure that the sealing force between the valve plate 14 and the valve seat 12 meets the design requirements. Fill water into the valve inlet to 1.2 times of the valve design pressure, and check the leakage situation at the valve outlet. If there is leakage, repeat S5.

[0131] In one embodiment, during the dynamic adjustment process, if after 3 times, the roughness still cannot meet the requirements, adjust according to the following formula:

[0132] ln(Ra(i) / K) = M·ln(I(i)) - N·ln(d(i));

[0133] Where: Ra(i) is the average roughness recorded at the i-th time;

[0134] I(i) is the discharge current corresponding to the i-th record;

[0135] d(i) is the working gap set at the i-th recording;

[0136] K is the roughness reference coefficient, which is used to reflect the influence degree of the discharge current I(i) on the roughness. The larger this value is, the more sensitive the change of the discharge current is to the final roughness during the machining process;

[0137] M is the current influence coefficient, which is used to reflect the influence degree of the discharge current I(i) on the roughness. The larger this value is, the more sensitive the change of the discharge current is to the final roughness during the machining process;

[0138] N is the gap influence coefficient, which is used to reflect the influence degree of the working gap d(i) on the roughness. The larger this value is, the more significant the influence of the gap on the roughness is;

[0139] By substituting the data of 3 groups or more (Ra(i), I(i), d(i)) into the above formula, the predicted values of the three parameters K, M, and N can be obtained; then, substitute the corresponding roughness Ra(i + 1) at the (i + 1)-th recording, the working gap d(i + 1) set at the (i + 1)-th recording, and the predicted values of K, M, and N into the following formula to obtain the recommended discharge current;

[0140] ;

[0141] Machine for 1 hour according to the recommended discharge current I(i + 1). If the requirements are still not met after 1 hour, repeat the above process.

[0142] The integrated machining process of the present invention combines subtractive machining, additive machining, finishing, and electric discharge machining into an overall process. By designing the valve body 11 and the valve seat 12 as an integral unit, the problem of pressure-bearing welds is avoided. In the field of valves in high-pressure environments, there is a great innovation in sealing performance and structural stability. And through high-precision machining methods, the design that one valve plate 14 can be adapted to multiple different valve bodies 11 is realized, solving the complexity problems in the maintenance and use in the field of valves. This interchangeable design of the valve plate 14 and the valve body 11 has great application value in the valve industry; the present invention realizes the dynamic adjustment of the electric discharge machining parameters through the optimization and adjustment combined with roughness detection, so as to ensure the accuracy of the gate valve after machining.

[0143] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to include all changes falling within the meaning and scope of the equivalent elements of the claims in the present invention.

Claims

1. A new type of integrated weld-free high-temperature and high-pressure gate valve, characterized by: include: A valve body (1) comprises a valve body (11) provided with a fluid channel (15) inside, a valve seat (12) integrally formed and provided inside the valve body (11), a valve cover (13) provided on the valve body (11), and a valve plate (14) for blocking the fluid channel (15); A transmission mechanism (2) comprising a ball screw (21) having one end passing through the valve cover (13) and connected to the valve plate (14), and a valve stem stopper (22) arranged on the ball screw (21); A fully enclosed electric mechanism (3), which is arranged on the valve cover (13) and connected to the other end of the ball screw (21) for driving the ball screw (21) to move; A position indicator (4) is obliquely arranged on both sides of the valve cover (13), perpendicular to the valve stem stopper (22) and matched with the valve stem stopper (22); The position indicator (4) comprises a pressure-bearing housing (41) arranged on the valve cover (13), and a push rod (43) having a ball head (42) at one end and cooperating with the valve stem stopper (22); The exterior of the valve stem stopper (22) is configured as a first inclined surface (221) and a second inclined surface (222) which are symmetrical in top and bottom, and the connection between the first inclined surface (221) and the second inclined surface (222) is configured as a spherical chamfer; The pushing rods (43) on both sides are respectively perpendicular to the first inclined surface (221) and the second inclined surface (222).

2. The novel integrated weld-free high-temperature and high-pressure gate valve according to claim 1 is characterized in that: The pressure-bearing shell (41) comprises a first shell (411) for arranging a ceramic piezoelectric sheet (44) and a second shell (412) whose inner cavity is larger than that of the first shell (411); the other end of the push rod (43) passes through the second shell (412) and extends into the first shell (411); a ceramic piezoelectric sheet (44) is arranged on the outside of a side wall of the first shell (411) away from the second shell (412); and a temperature measuring point (413) is arranged on the first shell (411).

3. The novel integrated weld-free high-temperature and high-pressure gate valve according to claim 2 is characterized in that: A ball guide sleeve (414) sleeved on the push rod (43) is provided on the second shell (412) in a tongue-and-groove connection and fixed by screws.

4. The novel integrated weld-free high-temperature and high-pressure gate valve according to claim 3 is characterized in that: A baffle (46) is provided on a section of the push rod (43) located inside the second shell (412), and a spring (45) is provided between the baffle (46) and the connection between the first shell (411) and the second shell (412).

5. The novel integrated weld-free high-temperature and high-pressure gate valve according to claim 4 is characterized in that: The measuring method of the position indicator (4) is as follows: Displacement = k / v × (1 + αΔT); Where: displacement is the measured displacement; v is the peak voltage of the third echo generated by the ceramic piezoelectric piece (44); k is the piezoelectric coefficient, which expresses the relationship between displacement and voltage; α is the temperature coefficient, which indicates the effect of temperature change on displacement; ΔT is the temperature change.

6. The novel integrated weld-free high-temperature and high-pressure gate valve according to claim 1 is characterized in that: The angle between the first inclined surface (221) and the vertical direction is A, and the angle A is calculated as follows: ； Where: r1 is half of the inner diameter of the valve cover (13) minus 3 mm; r2 is the radius of the valve stem; d is the theoretical maximum straight-line running distance of a gate valve with a diameter of d; d 误差 The error of the theoretical maximum straight-line running distance of the gate valve is ±0.5mm; 1 is half the length of the arc chord of the spherical chamfered surface.

7. A gate valve processing technology, characterized in that: The method for processing the novel integrated weld-free high-temperature and high-pressure gate valve according to any one of claims 1 to 6 comprises the following steps: S1. Subtractive processing: The outer shape and internal structure of the valve body (11) are processed. Based on the design drawings, the thickness of the sealing surface is reduced by 5±0.1 mm, and the thickness of the fluid channel (15) is increased by 1.2 mm, so as to obtain the basic structure of the valve body (11) and the valve seat (12); S2. Additive processing: The sealing surface is laser clad with cobalt-based alloy. The outlet sealing surface is processed first, and then the inlet sealing surface is processed. The two processing processes are the same; S3, finishing: finishing the valve body (11) after laser cladding according to the standard size of the design drawing; S4. Surface inspection and cleaning: Inspect the surface of the valve body (11) after fine machining, treat the cracked part and re-clad it until no cracks appear, and clean the valve body (11) with an ultrasonic cleaning machine to ensure that there are no impurities, oil stains, or foreign particles on the surface; S5, electric spark surface processing: processing the sealing surface of the valve seat (12) to ensure that the roughness of the sealing surface meets the sealing requirements; S6, water-tightness test: install the valve plate (14) in the valve body (11), simulate the motor by the push rod, ensure that the sealing force between the valve plate (14) and the valve seat (12) meets the design requirements, pressurize the valve inlet with water to 1.2 times the valve design pressure, check the valve outlet for leakage, and repeat S5 if leakage exists.

8. The gate valve processing process according to claim 7, characterized in that: In step S2, the steps for processing the sealing surface are specifically as follows: S21, place the valve body (11) to be processed into a workpiece heater, place the inlet end on a 5° inclined plane, and adjust the angle of the outlet sealing surface by a feeler gauge so that the outlet sealing surface is horizontal ±0.05°; S22, setting the heating temperature of the workpiece heater to 180°C, and setting the insulation range to ±10°C, taking five temperature points on the inner wall of the valve body (11), and the temperature difference between the highest and lowest temperatures is less than 5°C; S23. Since the heating process may cause the position to shift, check whether the angles of the outlet sealing surface and the inlet sealing surface meet the requirements; S24, push the laser head of the two-axis powder spraying laser cladding machine downward from the middle flange of the valve body (11), use a square spot with a size of 0.5*0.5 mm, set the cladding thickness to 3 mm, and process from the inside to the outside and from the left to the right. When processing near the edge of the fluid channel (15), adjust the cladding power until it is away from the edge of the fluid channel (15); S25. After the cladding is completed, the temperature of the valve body (11) of the workpiece heater is maintained at 180±10°C, and the temperature is cooled to room temperature after waiting for 4 hours to ensure that the workpiece has no cracks; S26, remove welding thermal stress, set the temperature of the workpiece heater to 700±30℃ for annealing, keep warm for 5h, then linearly cool down to 200℃, and the cooling time shall not be less than 24h; S27, remove the outermost layer in the cladding process, check whether the cladding layer has cracks, and if there are cracks, remove them together; S28. Repeat S21-S27 twice to ensure that the actual thickness of the cladding layer is greater than 5 mm.

9. The gate valve processing process according to claim 8, characterized in that: In the step S24, the cladding power is adjusted in the following manner: When the center of the light spot is processed to a distance of less than 1 mm from the edge of the fluid channel (15), the power is reduced by 20%; when the distance between the center of the light spot and the edge of the flow channel is 0.5 mm, the cladding is stopped, and the laser head performs an empty stroke until the distance between the center of the light spot and the edge of the fluid channel (15) is 0.5 mm, and then the laser head is started again, and the starting power is 80% of the set power; when the distance between the center of the light spot and the edge of the fluid channel (15) is 1 mm, the feed is adjusted to the set power.

10. The gate valve processing process according to any one of claims 7 to 9, characterized in that: The specific operation of step S5 is as follows: S51. Design and manufacture of electric spark electrodes: The electrode is a discharge body for machining the sealing surface of the valve seat (12). It is made of copper and has the same tooling structure as the valve plate (14). Its thickness is 0.1 mm less than that of the valve plate (14). S52, installing the valve body (11): installing the valve body (11) horizontally on the electric spark machining center, using the central axis of the upper flange of the valve body (11) as the center line to install the valve body (11) and the electric spark motor; S53, setting roughness reference lines: setting 10 reference lines as roughness reference lines on the upper flange section of the valve body (11), including 5 reference lines on the inlet sealing surface and 5 reference lines on the outlet sealing surface, setting a roughness detection instrument, and measuring the average roughness of the 10 reference lines. The roughness is measured from the upper flange of the valve body (11) downward until the sealing surface contacts the valve body (11); S54, set the parameters of the EDM machining center: set the discharge voltage to 80V, the discharge current to 2A, the pulse width to 10μs, the pulse interval to 50μs, the working gap to 20μm, and the discharge frequency to 500kHz; S55, Adaptive processing parameter optimization: Since the stress material on the cladding surface is not completely consistent during the cladding process, fixed parameters cannot be used for processing, but dynamic adjustments must be made based on the roughness measurement results.

11. The gate valve processing process according to claim 10, characterized in that: In the S55, the dynamic adjustment method is as follows: After every 15 minutes of processing, the roughness is tested and compared with the previous roughness. If the roughness does not change, the discharge current is reduced by 0.1A and the roughness Ra (i) is recorded. i represents the i-th time after the roughness does not change.

12. The gate valve processing process according to claim 11, characterized in that: During the dynamic adjustment process, if the roughness still cannot meet the requirements after 3 times, adjust according to the following formula: ln(Ra(i) / K)=M·ln(I(i))-N·ln(d(i)); Where: Ra(i) is the average roughness recorded for the i-th time; I(i) is the discharge current corresponding to the i-th recording; d(i) is the working interval set at the i-th recording; K is the roughness reference coefficient; M is the current influence coefficient; N is the gap influence coefficient; By substituting the three groups of data (Ra(i), I(i), d(i)) into the above formula, the predicted values ​​of the three parameters K, M, and N can be obtained; then the roughness Ra(i+1) corresponding to the i+1th record, the working gap d(i+1) set at the i+1th record, and the predicted values ​​of K, M, and N are substituted into the following formula to obtain the recommended discharge current; ； Process for 1 hour according to the recommended discharge current I (i+1). If the requirements are still not met after 1 hour, repeat the above process.

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