Novel valve seat sleeve of large-pressure-difference regulating valve

Abstract

The utility model belongs to the technical field of control valves, and discloses a novel valve seat sleeve of a large-pressure-difference regulating valve, which comprises a regulating valve seat body, an anti-erosion WC (Wolfram Carbide) valve seat sleeve, a compression valve seat sleeve nut and a positioning screw. On the basis of keeping the function of the original valve seat sleeve, the WC hard alloy valve seat sleeve is embedded on the valve seat body, so that the problems of valve seat cavitation, scouring and abrasion failure caused by the use environment of a control valve adjusting core component are solved under the condition of reducing the use amount, the service life of the core component is prolonged, and the service life of the core component is prolonged. And long-period, safe and reliable operation of core components in an application environment is ensured.

Description

TECHNICAL FIELD

[0001] The utility model belongs to control valve technical field, especially, it relates to a new big pressure difference governing valve valve seat cover. BACKGROUND

[0002] Control valve is a kind of special valve, it has the throttling or cut-off function of general valve, also has the regulating function of automatic control.Control valve application field is very wide, with the application of new material, new technology, new technology, fluid control industry field has put forward very high requirement and expectation to control valve, both to adapt to more and more demanding working condition regulation, more to reduce the frequency of maintenance, eliminate emergency shutdown, safe and reliable long running cycle, to realize production process optimization, stable, reduce production cost.Control valve core component is throttling element-valve core, valve seat or regulating valve cover.According to relevant data introduction, fluid industry, such as power generation, coal chemical industry, chemical industry, nuclear industry etc. field because control valve regulating throttling element failure causes emergency shutdown, or causes many major quality and personal safety accidents.

[0003] The main form of control regulating valve failure is cavitation and erosion damage of its regulating inner part-regulating valve core, throttling valve seat or throttling valve cover part.Cavitation is a kind of hydraulic flow phenomenon, when liquid medium flows through the throttling port of control valve, flow rate increases, pressure drops, when pressure drops to a certain value, i.e.saturated vapor pressure Pv, liquid begins to vaporize, liquid begins to gather bubbles, until flow rate reaches maximum, pressure drops to minimum Pvc, liquid gathers a large number of vapor bubbles, forms vapor-liquid two-phase flow, with the increase of flow cross section, flow rate decreases, pressure gradually recovers and increases, when pressure increases to more than liquid saturated vapor pressure Pv, vapor bubble breaks or explodes inward, thereby cavitation erosion occurs.Cavitation erosion damage features: the surface of valve core, valve seat or valve cover produces pit and rough surface similar to coal cinder, resulting in failure of throttling part of control valve.Another failure mode of throttling element of control valve is that liquid, solid particle-containing liquid and corrosive liquid medium pass through the throttling port, flow rate increases, forms high-speed erosion, abrasion and erosion to throttling regulating element valve core and valve seat or throttling valve cover, resulting in failure of throttling element.Erosion damage features: the surface of throttling element valve core, valve seat or valve cover produces metal material peeling, abrasion mark, deep groove, throttling element size distortion, etc., resulting in failure of throttling element of control valve.

[0004] At present, the large pressure differential pressure regulating control valve is prevented from being blocked by solid particles in the controlled fluid, and a multi-stage cage sleeve structure is usually used for adjusting, throttling, pressure reducing and flow control. The last stage of pressure reducing regulation adopts a porous pressure reducing valve sleeve structure of a whole nitriding hardening treatment of a nitriding steel material. The valve sleeve is selected from a Cr-Mo-Al type nitriding steel by a glow ion hardening process. The focus of the process method is to obtain a deeper part surface nitriding depth (generally up to 0.3-0.5 mm). The hardness distribution of the nitriding layer is that the depth of the surface layer of the part is 0.01-0.02 mm, the hardness is 920-1200 HV100 (equivalent to 85.3-88 HRA), the depth of the subsurface layer is 0.03-0.1 mm, the hardness is 800-900 HV100 (equivalent to 83-84.5 HRA), the nitriding layer is 0.2 mm, the hardness is 600 HV100 (equivalent to 79 HRA), and the nitriding layer is 0.3 mm, the hardness is 400 HV100 (equivalent to 70 HRA). From the above data, the nitriding hardness of the surface layer of the part is more ideal for anti-cavitation erosion effect. According to relevant information, the throttle hole on the pressure reducing valve seat sleeve cannot be chamfered due to manufacturing reasons, and the sharp corner part of the throttle hole cannot be chamfered. During the glow nitriding process, "decarburization" occurs at the sharp corner part of the throttle hole, causing "soft tissue band" to appear in the local organization of the throttle hole, that is, the hardness of the sharp corner part of the throttle hole edge is very low and equivalent to the matrix material, resulting in cavitation erosion and erosion failure of the throttle valve seat sleeve. Due to the failure of the control valve adjusting valve seat sleeve, emergency shutdown for repair is necessary during the running cycle.

[0005] As is known to all, tungsten carbide (WC) hard alloy is a fine carbon powder, black powder and binder Co or Ni powder mixed in a certain proportion by moulding, sintered in a high temperature vacuum special equipment. The parts made of tungsten carbide (WC) hard alloy usually have a minimum thickness not less than 5 mm, a hardness of 1200 HV100 (equivalent to 89 HRA), and a consistent hardness of the whole part, which is the most ideal material for anti-fluid medium cavitation, abrasion and erosion. Tungsten carbide (WC) hard alloy is special and difficult to process, and is expensive, so it is often applied to special and critical parts to reduce its use.

[0006] Through the above analysis, the problems and defects of the prior art are:

[0007] (1) The throttle hole on the pressure reducing valve seat sleeve cannot be chamfered due to manufacturing reasons, and the sharp corner part of the throttle hole cannot be chamfered.

[0008] (2) During the glow nitriding process, the carbon element in the metal material of the sharp corner part of the throttle hole is lost due to the ultra-high temperature generated during the process, that is, "decarburization", and the throttle hole cannot form a high-hardness hard nitriding carbon copolymer, and a low-hardness soft band organization appears.

[0009] (3) throttling valve sleeve in throttling and reducing pressure process of high-speed flow of vapor phase, vapor-liquid two-phase or vapor-liquid solid three-phase fluid medium in throttling orifice cavitation, erosion, erosion and other damage, resulting in the appearance of pits and coal slag surface roughness. Due to the failure of the control valve adjusting valve seat sleeve, emergency shutdown for repair is necessary during the running period. Practical new type content

[0010] In view of the problems existing in the prior art, the utility model provides a novel big pressure difference regulating valve valve seat sleeve.

[0011] The utility model discloses a novel big pressure difference regulating valve valve seat sleeve, which comprises:

[0012] The adjusting valve seat body is used for providing the mounting base of the valve seat sleeve.

[0013] The anti-erosion WC valve seat sleeve is arranged in the adjusting valve seat body and can withstand the impact of high-pressure difference fluid and improve the durability of the regulating valve through its anti-erosion property.

[0014] The positioning screw is installed on the adjusting valve seat body and is used for positioning and fixing the anti-erosion WC valve seat sleeve in the adjusting valve seat body to prevent the valve seat sleeve from shifting.

[0015] The pressing valve seat sleeve nut is fixed on the adjusting valve seat body through threaded connection and is used for fastening the anti-erosion WC valve seat sleeve in the adjusting valve seat body.

[0016] Further, the adjusting valve seat body is made of 38CrMoAl, which belongs to the nitrogenized steel.

[0017] Further, the anti-erosion WC valve seat sleeve is made of tungsten carbide hard WC alloy.

[0018] Further, the pressing valve seat sleeve nut is made of 38CrMoAl.

[0019] In combination with the above technical scheme and the technical problems solved, the technical scheme to be protected by the utility model has the following advantages and positive effects:

[0020] Firstly, the utility model reduces the use amount by embedding the WC hard alloy valve seat sleeve on the valve seat body on the basis of keeping the function of the original valve seat sleeve, solves the failure of the valve seat cavitation, erosion and abrasion of the core component of the control valve caused by the use environment, improves the service life of the core component, and ensures the long-period, safe and reliable operation of the core component in the application environment.

[0021] The utility model improves the cavitation erosion, erosion and abrasion resistance of the throttling and regulating sleeve of the throttling core component of the control valve, i.e. the throttling and regulating sleeve, by embedding the tungsten carbide (WC) throttling and regulating sleeve on the original integral valve seat sleeve on the basis of keeping the function of the original component unchanged.

[0022] The core component anti-erosion WC valve seat sleeve of the utility model is pressed into a blank preform by adding binder elements Co or Ni in a certain proportion to tungsten carbide powder in a mold, due to the particularity of forming and the super-high hardness characteristics after forming, the throttling regulating holes are finally formed by mechanical equipment in advance on the preform according to the design requirements of regulating control. In order to guarantee the size, shape and position precision and yield of the throttling holes of the anti-erosion WC valve seat sleeve, test data show that the diameter size of the regulating throttling holes should be controlled in 4-8mm, the hole walls of the two throttling holes and the distance from the edges of the parts should not be less than 4mm.

[0023] The core component of the utility model has simple structure, the tungsten carbide (WC) throttling regulating sleeve is convenient to disassemble and replace, positioning is reliable and cost is low.

[0024] Secondly, the expected income and commercial value of the technical scheme of the utility model after transformation are:

[0025] After transformation of the technical scheme of the utility model, the anti-cavitation, erosion and scouring capability of the core component of the large-pressure-difference small-flow control valve is remarkably improved, the long-period, safe and reliable operation of the core component in the application environment is guaranteed, and the optimal economic benefit and social benefit are realized with a small amount of rare and expensive materials and controllable cost.

[0026] The technical scheme of the utility model provides a kind of thought for practitioners, and realizes the maximization of economic benefit and social benefit in the optimal economic mode by adopting the form of superposition and combination in combination with application environment and fault problems.

[0027] The technical scheme of the utility model solves the problems that people have been eager to solve, such as the control valve of the liquid process control system in the application environment with weak corrosion, solid particles, large pressure difference and large temperature and flow variation range, the failure of the regulating element-cage valve seat sleeve caused by cavitation, erosion and scouring, and the short period of production operation, which also brings hidden dangers to safe production. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a structure diagram of a novel large-pressure-difference regulating valve seat sleeve provided by the utility model embodiment.

[0029] Figure 2 is a structure diagram of a regulating valve seat body provided by the utility model embodiment.

[0030] Figure 3 is a structure diagram of an anti-erosion WC valve seat sleeve provided by the utility model embodiment.

[0031] Figure 4 is a structure diagram of a compressed valve seat sleeve nut provided by the utility model embodiment.

[0032] Figure 5The utility model technical scheme effect picture provided by the embodiment of the utility model.

[0033] In the figure: 1, adjusting valve seat body, 2, anti-erosion WC valve seat sleeve, 3, press valve seat sleeve nut, 4, positioning screw. DETAILED DESCRIPTION

[0034] In order to make the utility model purposes, technical scheme and advantages more clear and obvious, the following with examples, the utility model is further detailed.The specific embodiments described here are merely used to explain the utility model and not to limit the utility model.

[0035] The big pressure difference adjusting valve valve seat sleeve provided by the embodiment of the utility model mainly comprises adjusting valve seat body, anti-erosion WC valve seat sleeve, press valve seat sleeve nut and positioning screw.The purpose of the design is to improve the erosion resistance of the adjusting valve under high pressure difference conditions, while ensuring its long-term stable operation.

[0036] Firstly, the anti-erosion WC valve seat sleeve is installed in the adjusting valve seat body.The anti-erosion WC valve seat sleeve is made of hard material, has strong wear resistance and erosion resistance, and is suitable for harsh working conditions with high pressure difference.The anti-erosion WC valve seat sleeve can effectively withstand the high-frequency impact of the valve core and the fluid through its special design structure, reduce the wear of the valve seat sleeve, and improve the service life of the adjusting valve.

[0037] Secondly, the positioning screw is used to fix the anti-erosion WC valve seat sleeve in the adjusting valve seat body, to ensure that the valve seat sleeve does not shift during work.The design of the positioning screw ensures the close combination of the anti-erosion WC valve seat sleeve and the adjusting valve seat body, while avoiding the sealing failure and leakage caused by the loosening of the valve seat sleeve.

[0038] Thirdly, the press valve seat sleeve nut is fastened through the thread on the adjusting valve seat body.Through the thread structure, the press valve seat sleeve nut exerts a certain pressure on the anti-erosion WC valve seat sleeve, ensuring that it can still maintain stable positioning under high pressure conditions.This structure makes the anti-erosion WC valve seat sleeve not displace under high pressure difference conditions, thereby maintaining the stability of the adjusting valve.

[0039] In addition, the adjusting valve seat body serves as a support structure, bearing the anti-erosion WC valve seat sleeve and the positioning screw, and also reduces the vortex and turbulence of the fluid through its special flow channel design, thereby further reducing the erosion effect on the valve seat sleeve.The strength design of the adjusting valve seat body ensures that it can withstand high pressure difference impact and long-term working pressure.

[0040] When fluid enters the regulating valve, the anti-erosion WC valve seat sleeve bears the main impact load. Due to the material properties and structural design, the wear resistance and anti-erosion performance of the valve seat sleeve are greatly improved, so that the regulating valve can still maintain good working condition under long-time high-pressure difference working condition. The compression nut further stabilizes the structure and prevents the parts from loosening under high-pressure difference working condition.

[0041] Finally, through the precise design of the combination and assembly relationship, the parts can work cooperatively, so that the regulating valve has strong anti-erosion, stable positioning performance and long service life, and solves the problem that the regulating valve is easily damaged under high-pressure difference working condition in the prior art. This design not only improves the performance of the regulating valve, but also significantly prolongs the maintenance period of the equipment.

[0042] As shown in Figure 1 The utility model embodiment provides a novel big pressure difference regulating valve valve seat sleeve, which comprises:

[0043] The regulating valve seat body 1, the anti-erosion WC valve seat sleeve 2, the compression valve seat sleeve nut 3 and the positioning screw 4.

[0044] As shown in Figure 2 , 4 The anti-erosion WC valve seat sleeve 2 is arranged in the regulating valve seat body 1; and the anti-erosion WC valve seat sleeve 2 is positioned in the regulating valve seat body 1 through the positioning screw 4.

[0045] As shown in Figure 3 The compression valve seat sleeve nut 3 fixes the anti-erosion WC valve seat sleeve 2 on the regulating valve seat body 1 through the threads on the regulating valve seat body 1.

[0046] The regulating valve seat body provided in the utility model embodiment is made of 38CrMoAl, which belongs to the nitrogenized steel. After glow discharge ion nitriding treatment, the surface hardening layer of the material has a thickness of 0.3-0.5 mm.

[0047] The anti-erosion WC valve seat sleeve provided in the utility model embodiment is made of tungsten carbide (WC) alloy, is usually made by compression sintering, has a thickness of not less than 5 mm, has uniform hardness at each cross section, and has a hardness of not less than 89HRA (relative to 1250HV100) and a hardness of 1250HV100.

[0048] The compression valve seat sleeve nut provided in the utility model embodiment is made of 38CrMoAl and is subjected to surface nitriding treatment, and has the same characteristics as the regulating valve seat body.

[0049] The technical scheme of the utility model is applied to the regulating valve sleeve, which is a core pressure reduction regulating element of a regulating valve for controlling a small flow of a weakly corrosive liquid medium under a big pressure difference.

[0050] The utility model discloses an embodiment provides a kind of structure design of novel big pressure difference regulating valve valve seat cover, and the performance of erosion resistance and corrosion resistance under the condition of big pressure difference small flow is realized by reasonable material selection and component connection mode.The following is its detailed working principle:

[0051] 1. The composition and function of the regulating valve seat body

[0052] The regulating valve seat body 1 is made of 38CrMoAl nitriding steel, and the surface layer is formed with a hardened layer of 0.3-0.5 mm in thickness through glow plasma nitriding treatment, effectively improving the wear resistance and erosion resistance. Specifically, the nitriding layer has different hardness in different layers, and the hardness of the outermost layer can reach more than 920HV100, providing high wear resistance. This structure design ensures that the regulating valve seat body can withstand strong erosion under high pressure difference conditions, prolonging its service life.

[0053] 2. Installation and protection function of erosion-resistant WC valve seat cover

[0054] The erosion-resistant WC valve seat cover 2 is made of tungsten carbide hard alloy material, which has excellent wear resistance and hardness. The thickness is not less than 5 mm, and the hardness of the cross section is uniform, reaching more than 89HRA. The valve seat cover is installed in the regulating valve seat body 1 and in contact with the fluid, and can directly withstand the impact of high-pressure liquid. The high hardness of tungsten carbide material ensures that it is not easily worn out during long-term use, effectively protecting the valve seat body and improving the erosion resistance of the valve in harsh environments.

[0055] 3. Fixing effect of positioning screw

[0056] The erosion-resistant WC valve seat cover 2 is fixed in the regulating valve seat body 1 by the positioning screw 4, ensuring that the valve seat cover will not be displaced due to the high pressure impact of the fluid. The positioning screw provides precise positioning, ensuring the stability of the WC valve seat cover, so that it always remains in the best position in the high pressure difference environment, thereby ensuring the accuracy and reliability of the regulating valve in the fluid control process.

[0057] 4. Compression function of valve seat cover nut

[0058] The valve seat cover nut 3 is installed on the regulating valve seat body 1, and the erosion-resistant WC valve seat cover 2 is firmly fixed by screw connection. Through the compression of the valve seat cover nut, it is ensured that the valve seat cover will not loosen during use, effectively preventing the impact of vibration caused by high pressure difference on the valve seat cover, ensuring the safety and stability of the valve seat.

[0059] 5. Synergistic effect of pressure reduction and erosion resistance

[0060] In the case of high pressure difference and small flow, the impact force generated by the fluid passing through the adjusting valve seat sleeve is large, and the high hardness performance of the anti-erosion WC valve seat sleeve effectively absorbs and resists these impacts, playing a role in protecting the adjusting valve seat body. At the same time, due to the gradual relief of fluid pressure, the valve seat sleeve plays a role in reducing pressure, allowing the subsequent fluid to flow out more smoothly, improving the stability of the entire regulating system.

[0061] 6. Combination protection of anti-erosion material and nitriding layer

[0062] The material selection of the valve seat sleeve and the adjusting valve seat body 1 has a synergistic effect: the anti-erosion WC valve seat sleeve directly contacts the fluid through the high hardness tungsten carbide material, providing a layer of protection; while the nitriding layer on the surface of the adjusting valve seat body provides secondary protection against erosion and wear caused by high pressure fluid, ensuring durability under fluid erosion. This combined design enables the device to remain long-lasting in extreme environments.

[0063] 7. Corrosion resistance of the overall device

[0064] By nitriding the key components, especially the adjusting valve seat body and the compression valve seat sleeve nut made of 38CrMoAl material treated by nitriding, the overall corrosion resistance is improved. Even in the environment of adjusting valve used for weakly corrosive liquid medium, the stability of the material can still be guaranteed, preventing performance degradation caused by corrosion.

[0065] 8. Design features suitable for high pressure difference and small flow control

[0066] This device is suitable for the core components of the adjusting valve in the case of large pressure difference and small flow. The anti-erosion WC valve seat sleeve, through precise size and flow channel design, can ensure the accuracy of the valve in flow control. With the auxiliary protection of the nitriding layer and the toughness of the anti-erosion material, the device achieves stable, long-lasting, and reliable working performance in the environment of high pressure difference and small flow, effectively avoiding wear and corrosion problems in the fluid control process, and improving the overall durability and service life of the valve.

[0067] In June 2023, a chemical company's main product high-pressure section had the following process technical parameters: working temperature ≤270℃, control adjusting valve inlet pressure 17~20Mpa, outlet pressure 0.6Mpa, control flow 20m 3 / h, the control valve is initially selected from a large valve enterprise in China GYT44-320-DN65 high temperature and large pressure regulating valve, the valve application is less than half a year, the regulating function is invalid, the emergency shutdown is overhauled, the valve is disassembled, the last stage regulating valve sleeve of the valve core is seriously eroded, the regulating valve sleeve is made of 38CrMoAl material, the surface is nitrided, and the integrated regulating valve sleeve is replaced by the technical scheme of the utility model in October, 2023, and the valve whole machine runs to September, 2024, the regulating function is normal, and the system runs well.

[0068] The above is only a specific embodiment of the utility model, but the protection scope of the utility model is not limited to this, any skilled person in the art can make any modification, equivalent replacement and improvement within the technical range disclosed by the utility model, and the modification, equivalent replacement and improvement within the spirit and principles of the utility model should be covered in the protection scope of the utility model.

Claims

1. A new type of large differential pressure control valve seat sleeve, characterized in that, The utility model relates to a kind of anti-erosion WC valve seat sleeve and anti-erosion WC valve seat sleeve installation structure, including: Adjusting valve seat body (1) is used to provide the installation base of valve seat sleeve; Anti-erosion WC valve seat sleeve (2) is arranged in adjusting valve seat body (1), can withstand the impact of high pressure difference fluid, and the durability of regulating valve is improved by its anti-erosion property; Positioning screw (4) is installed on adjusting valve seat body (1), for positioning and fixing anti-erosion WC valve seat sleeve (2) in adjusting valve seat body (1), prevent valve seat sleeve displacement; Compression valve seat sleeve nut (3) is fixed by thread connection on adjusting valve seat body (1), for anti-erosion WC valve seat sleeve (2) is fastened in adjusting valve seat body (1).

2. The new generation large pressure-differential control valve seat sleeve according to claim 1, characterized in that, The outer surface of the anti-erosion WC valve seat sleeve (2) is connected with the inner surface of the adjusting valve seat body (1) by the positioning screw (4).

3. The new generation large differential pressure control valve seat insert of claim 1, wherein, The compression valve seat sleeve nut (3) is tightly fixed in the adjusting valve seat body by thread connection with the adjusting valve seat body (1).

4. The new generation large pressure-differential control valve seat insert according to claim 1, characterized in that, The material of the anti-erosion WC valve seat sleeve (2) is cemented carbide.

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