Lining plastic regulating valve

Abstract

The utility model discloses a lining plastic regulating valve which comprises a valve body, a valve core, a valve rod and a valve cover, the valve core and the valve rod are inserted into the valve body after being connected, and a combined sealing structure and the valve cover are arranged outside the valve rod to seal the valve rod. According to the pneumatic corrugated pipe plastic lining single-seat regulating valve, the valve body, the valve core, the valve rod and the valve cover are all provided with the lining layers, and a corrugated pipe-filler double-sealing structure is adopted between the upper valve cover and the valve rod, so that fluid media are effectively prevented from leaking outwards from a movement gap of the valve rod; the defects of packing aging, temperature difference sensitivity and the like of an existing packing seal valve are overcome, the safety and the reliability are better, and the packing seal valve can be applied to an automatic control system of rare special media such as highly toxic media, highly corrosive media and radioactive media.

Description

Technical Field

[0001] The utility model relates to the technical field of regulating valves, in particular to a plastic-lined regulating valve. Background Art

[0002] The regulating valve, also known as the control valve, is a key component in industrial automation process control. It receives the signal output by the regulating control unit and changes the process parameters such as medium flow, pressure, temperature or liquid level through power operation. It is usually composed of an actuator and a valve. According to the stroke characteristics, the regulating valve can be divided into two types: linear stroke and angular stroke. According to the power type of the equipped actuator, it can be divided into three types: pneumatic, electric and hydraulic. According to the function and characteristics, it can be divided into linear, percentage and parabolic characteristics. The regulating valve is suitable for a variety of media, including air, water, steam, various corrosive media, mud and oil.

[0003] Plastic-lined valves use corrosion-resistant plastic materials to line the inner cavity and internal parts of the valve, so they are widely used in the regulation and control of corrosive media such as hydrochloric acid, sulfuric acid, hydrofluoric acid, nitric acid, aqua regia, and other strong alkalis and oxidants. Since the regulating valve is usually used as the final control element, the valve stem often needs to move to open or close the valve. Existing packing seal valves usually have weaknesses such as packing aging and temperature difference sensitivity. When the medium generates a vacuum in the pipeline, the pure fluoroplastic bellows is not strong enough and is easily deformed under the influence of temperature and pressure, causing the medium to leak out from the valve stem movement gap, thereby affecting the sealing performance and service life of the product. Utility Model Content

[0004] The purpose of the utility model is to solve the above problems and provide a plastic-lined regulating valve.

[0005] In order to achieve the above-mentioned purpose, the utility model specifically adopts the following technical solutions:

[0006] A plastic-lined regulating valve comprises a valve body, a valve core, a valve stem and a valve cover, wherein the valve core and the valve stem are connected and inserted into the valve body, and a combined sealing structure and a valve cover are arranged outside the valve stem to seal the valve stem;

[0007] The combined sealing structure includes a bellows and a packing layer. The bellows is sleeved on the outside of the valve stem. The packing layer is arranged on the periphery of the connection between the valve stem and the tail of the valve cover. A metal bushing is also sleeved between the bellows and the valve stem. The valve stem is sealed by the bellows and the packing layer.

[0008] As a further description of the above technical solution, the valve body and the valve cover are connected by bolts and nuts, and the valve body, valve core, valve stem and valve cover are provided with an inner lining layer, and the inner lining layer includes a first lining plastic layer, a second lining plastic layer and a third lining plastic layer.

[0009] As a further description of the above technical solution, the material of the inner lining layer is FEP, and the thickness of the inner lining layer is 2-5 mm.

[0010] As a further description of the above technical solution, a medium channel is opened inside the valve body, and a first lining plastic layer is provided on the inner wall of the medium channel.

[0011] As a further description of the above technical solution, the valve core head is hemispherical, the step surfaces of the valve core and the medium channel abut against each other, and a second lining plastic layer is provided outside the valve core and the valve stem.

[0012] As a further description of the above technical solution, a sealing channel is opened inside the valve cover, and a third lining plastic layer is arranged on the inner wall of the sealing channel.

[0013] As a further description of the above technical solution, a bracket is provided on the valve cover, and a sliding groove is provided on the bracket for the connecting block to be inserted and slided. The tail of the valve stem is connected through the connecting block and the pneumatic head above the bracket, and the valve stem movement is driven by the pneumatic head to control the opening and closing of the medium channel.

[0014] As a further description of the above technical solution, the material of the bellows is FEP or PFA.

[0015] As a further description of the above technical solution, the material of the packing layer is PTFE, and the diameter of the packing layer is less than or equal to the diameter of the bellows.

[0016] As a further description of the above technical solution, a packing gland is arranged above the packing layer, and the packing gland and the bracket are connected by bolts and nuts.

[0017] The beneficial effects of the utility model are as follows:

[0018] 1. In the utility model, the valve body, valve core, valve stem and valve cover of the pneumatic bellows lined plastic single-seat regulating valve are all provided with an inner lining layer, and a bellows-filling double sealing structure is adopted between the upper valve cover and the valve stem, which effectively prevents the fluid medium from leaking outward from the valve stem movement gap, overcomes the weaknesses of the existing packing sealing valves such as packing aging and temperature difference sensitivity, has better safety and reliability, and can be applied to the automatic control system of rare and special media such as highly toxic, highly corrosive and radioactive media;

[0019] 2. The utility model comprises a top guide structure composed of a valve body, a valve core, a valve stem and a valve cover. The valve body has a compact structure, an S-shaped medium channel, a small pressure drop loss, a large flow rate, a wide adjustable range, a large valve core guide area, and good vibration resistance. The metal shell and the inner lining layer are joined by tooth processing in the inner cavity of the valve body and the valve cover, which effectively prolongs the service life and performance of the inner lining layer material. The valve stem seal adopts a combination of a bellows seal made of PFA or FEP material and a V-shaped PTFE packing, and an inner metal sleeve, which effectively enhances the sealing strength, ensuring that when the medium generates a vacuum in the pipeline, the pure plastic bellows will not be sucked by the vacuum, thereby causing the bellows to be damaged and leak.

[0020] In order to more clearly illustrate the structural features and functions of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a structural schematic diagram of the plastic-lined regulating valve of the utility model;

[0022] Figure 2 yes Figure 1 Schematic diagram of the enlarged structure at AA in the middle.

[0023] Reference numerals:

[0024] 1. Valve body; 11. Medium channel; 2. Valve core; 3. Valve stem; 4. Valve cover; 41. Sealing channel; 5. Combined sealing structure; 51. Bellows; 52. Packing layer; 53. Metal bushing; 6. Inner lining layer; 61. First plastic lining layer; 62. Second plastic lining layer; 63. Third plastic lining layer; 7. Connecting block; 8. Bracket; 9. Pneumatic head; 10. Packing gland. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present utility model clearer, the technical solution in the embodiments of the present utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the present utility model.

[0026] like Figure 1-Figure 2 As shown, in one embodiment, a plastic-lined regulating valve includes a valve body 1, a valve core 2, a valve stem 3 and a valve cover 4. The valve core 2 and the valve stem 3 are connected and inserted into the valve body 1 to form a top guide structure.

[0027] Among them, a combined sealing structure 5 and a valve cover 4 are arranged outside the valve stem 3 to seal the valve stem 3, and the metal shell and the lining layer 6 in the inner cavity of the valve body 1 and the valve cover 4 are perfectly joined through tooth processing, thereby effectively isolating the corrosion of the corrosive medium on the valve metal material, which can extend the service life of the lining layer 6 material, improve its corrosion resistance, and enable the valve to operate stably for a long time in the working environment of the corrosive medium.

[0028] like Figure 1-Figure 2 As shown, in this embodiment, the valve body 1, the valve core 2, the valve stem 3 and the valve cover 4 are provided with an inner lining layer 6, and the inner lining layer 6 includes a first lining plastic layer 61, a second lining plastic layer 62 and a third lining plastic layer 63. The material of the inner lining layer 6 is FEP (fluoroethylene propylene), which has excellent chemical resistance, heat resistance, electrical insulation, weather resistance and low friction coefficient, etc., and provides a soft connection between the valve body 1, the valve core 2 and the valve stem 3, effectively improving the sealing effect. Specifically, the thickness of the inner lining layer 6 is 2-5 mm.

[0029] Furthermore, the valve body 1 and the valve cover 4 are connected by bolts and nuts, a medium channel 11 is provided inside the valve body 1, and the inner wall of the channel is covered with a first lining plastic layer 61. The overall structure is compact, and the medium channel 11 is S-shaped and streamlined, so that the valve has a small pressure drop loss and a large flow rate when working, and has a wide adjustment range to meet different usage requirements.

[0030] Furthermore, a second lining plastic layer 62 is provided outside the valve core 2 and the valve stem 3, the head of the valve core 2 is hemispherical, and the step surfaces of the valve core 2 and the medium channel 11 abut against each other, which increases the guide area and improves the vibration resistance of the valve.

[0031] Furthermore, a sealing channel 41 is provided inside the valve cover 4, and a third plastic lining is covered on the inner wall thereof. A bracket 8 is provided above the valve cover 4, and a sliding groove is provided on the bracket 8 for the connection block 7 to be inserted and slided. The tail of the valve stem 3 is connected to the pneumatic head 9 above the bracket 8 through the connection block 7, and the movement of the valve stem 3 is controlled by the driving of the pneumatic head 9, thereby realizing the opening and closing operation of the medium channel 11.

[0032] like Figure 1-Figure 2 As shown, in this embodiment, the combined sealing structure 5 includes a bellows 51 and a packing layer 52. The bellows 51 is sleeved on the outside of the valve stem 3, and a metal bushing 53 is sleeved between the bellows 51 and the valve stem 3 to ensure that the pure plastic bellows 51 will not be sucked and damaged in a vacuum environment, so that the seal is damaged. The packing layer 52 is arranged on the periphery of the connection between the valve stem 3 and the valve cover 4 at the tail, and the valve stem 3 is sealed by the bellows 51 and the packing layer 52, which effectively improves the sealing effect. A packing gland 10 is arranged above the packing layer 52, and the packing gland 10 and the bracket 8 are connected by bolts and nuts, and the diameter of the packing layer 52 is less than or equal to the diameter of the bellows 51.

[0033] Specifically, the material of the bellows 51 is FEP (fluoroethylene propylene) or PFA (perfluoroalkoxy resin), and the material of the filler layer 52 is PTFE (polytetrafluoroethylene). This type of fluoroplastic has excellent dielectric properties and chemical corrosion resistance, high and low temperature resistance, waterproofness, non-stickiness, low friction coefficient, good self-lubrication and other properties.

[0034] Working principle: The valve stem 3 seal adopts a combination of a bellows 51 seal made of PFA or FEP material and a V-shaped PTFE packing. The inner frame has a metal sleeve and a plastic lining layer for soft sealing, which effectively enhances the sealing strength and corrosion resistance. It can withstand the corrosion of almost all media (including concentrated nitric acid and aqua regia), ensuring that when the medium generates a vacuum in the pipeline, the pure plastic bellows 51 will not be sucked by the vacuum, and there will be no damage to the bellows 51 due to insufficient strength, resulting in damage to the seal and leakage.

[0035] Through the above technical scheme, the present application uses a bellows 51-packing double sealing structure to achieve sealing between the valve cover 4 and the valve stem 3, effectively preventing the fluid medium from leaking from the movement gap of the valve stem 3, overcoming the common problems of packing aging and temperature difference sensitivity of existing packing sealing valves, and having better safety and reliability. It can be widely used in automatic control systems for rare and special media such as highly toxic, highly corrosive and radioactive media, such as valves set at the corrosion-resistant vacuum pump port for adjusting flow.

[0036] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A plastic-lined regulating valve, comprising a valve body (1), a valve core (2), a valve stem (3) and a valve cover (4), characterized in that: The valve core (2) and the valve stem (3) are connected and inserted into the valve body (1); a combined sealing structure (5) and a valve cover (4) are arranged outside the valve stem (3) to seal the valve stem (3); The combined sealing structure (5) comprises a bellows (51) and a packing layer (52); the bellows (51) is sleeved on the outside of the valve stem (3); the packing layer (52) is arranged on the periphery of the connection between the tail of the valve stem (3) and the valve cover (4); a metal bushing (53) is also sleeved between the bellows (51) and the valve stem (3); the valve stem (3) is sealed by the bellows (51) and the packing layer (52).

2. The plastic-lined regulating valve according to claim 1, characterized in that: The valve body (1) and the valve cover (4) are connected by bolts and nuts. The valve body (1), the valve core (2), the valve stem (3) and the valve cover (4) are provided with an inner lining layer (6). The inner lining layer (6) comprises a first lining plastic layer (61), a second lining plastic layer (62) and a third lining plastic layer (63).

3. The plastic-lined regulating valve according to claim 2, characterized in that: The material of the inner lining layer (6) is FEP, and the thickness of the inner lining layer (6) is 2-5 mm.

4. The plastic-lined regulating valve according to claim 1, characterized in that: A medium channel (11) is provided inside the valve body (1), and a first lining plastic layer (61) is provided on the inner wall of the medium channel (11).

5. The plastic-lined regulating valve according to claim 1, characterized in that: The head of the valve core (2) is hemispherical, the step surfaces of the valve core (2) and the medium channel (11) abut against each other, and a second lining plastic layer (62) is provided outside the valve core (2) and the valve stem (3).

6. The plastic-lined regulating valve according to claim 1, characterized in that: A sealing channel (41) is provided inside the valve cover (4), and a third lining plastic layer (63) is provided on the inner wall of the sealing channel (41).

7. The plastic-lined regulating valve according to claim 1, characterized in that: The valve cover (4) is provided with a bracket (8), and the bracket (8) is provided with a sliding groove for the connection block (7) to be inserted and slide. The tail of the valve stem (3) is connected to the pneumatic head (9) above the bracket (8) through the connection block (7), and the pneumatic head (9) drives the valve stem (3) to move and control the opening and closing of the medium channel (11).

8. The plastic-lined regulating valve according to claim 1, characterized in that: The material of the bellows (51) is FEP or PFA.

9. The plastic-lined regulating valve according to claim 1, characterized in that: The material of the packing layer (52) is PTFE, and the diameter of the packing layer (52) is less than or equal to the diameter of the bellows (51).

10. The plastic-lined regulating valve according to claim 1, characterized in that: A packing gland (10) is arranged above the packing layer (52), and the packing gland (10) and the bracket (8) are connected via bolts and nuts.

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