Wear-resistant high-frequency cut-off ball valve

Abstract

This utility model discloses a wear-resistant high-frequency shut-off ball valve, relating to the field of industrial valve technology. The aim is to optimize the material and structure of the valve internals of a high-frequency feed shut-off valve to improve the overall service life and performance of the valve. The proposed technical solution includes a valve body, two annular valve seats disposed on the inner wall of the valve body, a ball supported between the two annular valve seats, and a valve stem connected to the top of the ball. The ball is made of 316 stainless steel with a tungsten carbide coating on its surface. An annular anti-wear groove is provided on the inner wall of the valve body, and the annular valve seats are installed within the annular anti-wear groove. A packing layer is also provided on the inner wall of the valve body, made of polytetrafluoroethylene or graphite. This utility model's metal-based ball combined with the tungsten carbide coating can withstand high-frequency torque impacts, eliminating the risk of ceramic breakage. The valve stem and ball are connected by an integrated short-shaft structure to avoid slurry retention, greatly improving the stability and lifespan of the device.

Description

Technical Field

[0001] This utility model relates to the field of industrial valve technology, specifically to a wear-resistant high-frequency shut-off ball valve. Background Technology

[0002] In the dewatering stage of lithium carbonate slurry, centrifuge technology is often used for slurry dewatering, employing a batch-feed continuous operation process. A single batch typically involves five steps: feeding, washing, spin-drying, backwashing, and scraping. The entire batch takes approximately 15 minutes, during which the centrifuge operates at a constant speed. Multiple interval feedings are used within a single batch, often 5-6 times, with feeding times ranging from 30-50 seconds and intervals from 20-40 seconds. Therefore, the centrifuge feed shut-off valve is a high-frequency valve. The valve operates at a high frequency, with up to 2 million cycles per year.

[0003] Lithium carbonate slurry, characterized by high density and high particle hardness, easily wears down the seals of conventional valves, leading to internal leakage. Combined with frequent switching operations and rapid wear of conventional packing, external leakage is highly likely. Internal leakage refers to the media leaking through the sealing surface between the valve seat and body even when the valve is closed, causing pressure loss and inaccurate flow control in the system. External leakage refers to the media leaking into the external environment from other parts of the valve, such as the connection between the valve stem and stuffing box, or the valve body, affecting product quality and causing interruptions in continuous production. In this operating condition, conventional soft-seal valves, hard-seal valves, plug valves, V-type hard-seal valves, and ceramic valves have all been used. The performance of all these valves was unsatisfactory, with internal and external leakage occurring within approximately three months.

[0004] Conventional O-type ball ceramic valves, whether made of zirconia or alumina, perform well under normal acid and alkali conditions. However, their performance deteriorates under conditions of high slurry density, high particle hardness, and corrosion, leading to ball breakage within a short period. The root cause lies in a design flaw in the valve's internal components, where material easily accumulates between the ball, the valve body flow channel cavity, and the valve stem. Under high torque, this can easily cause the ball to break. Utility Model Content

[0005] This utility model provides a wear-resistant high-frequency shut-off ball valve, the purpose of which is to optimize the internal components of the high-frequency feed shut-off valve in order to improve the service life and performance of the valve.

[0006] The technical solution of this utility model to solve the above-mentioned technical problems is as follows:

[0007] A wear-resistant high-frequency shut-off ball valve includes a valve body, two annular valve seats disposed on the inner wall of the valve body, a ball supported between the two annular valve seats, and a valve stem connected to the top of the ball. The ball is made of 316 stainless steel and has a tungsten carbide coating on its surface. The inner wall of the valve body is provided with an annular anti-wear groove, and the annular valve seats are installed in the annular anti-wear groove. The inner wall of the valve body is also provided with a packing layer, the material of which is polytetrafluoroethylene or graphite.

[0008] Furthermore, the annular anti-wear groove has a depth of 1.5 mm and a width of 2 mm.

[0009] Furthermore, the surface roughness of the valve body flow channel is Ra = 0.6 μm, and the clearance between the valve body flow channel and the ball is 0.8 mm.

[0010] Furthermore, the valve stem and ball are connected by an integrated short-shaft structure.

[0011] Furthermore, the tungsten carbide coating has a spray thickness of 5±0.2 mm.

[0012] This utility model has the following beneficial effects:

[0013] This invention replaces the ceramic sphere with a metal-based sphere and coats the surface of the metal sphere with a tungsten carbide coating, enabling the sphere to withstand high-frequency torque impacts and fundamentally eliminating the risk of ceramic breakage. Furthermore, an annular anti-wear groove on the inner wall of the valve body compensates for wear and prevents leakage. The valve stem and sphere are connected by an integrated short-shaft structure to avoid slurry retention. Actual continuous operation has been measured for more than 18 months, a six-fold improvement over the previous three months, significantly enhancing the stability and service life of the device. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the wear-resistant high-frequency shut-off ball valve of this utility model;

[0015] Figure 2 This is a schematic diagram of the valve stem structure;

[0016] Figures 1 to 2 The reference numerals in the attached drawings represent: valve body 1, ball 2, ball channel 21, annular valve seat 3, annular anti-wear groove 31, valve stem 4, valve stem body 41, ball connection end 42, and packing layer 5. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0018] In this utility model, the terms "longitudinal," "lateral," "vertical," "upper," "lower," "front," "rear," "left," "right," "top," and "bottom," etc., indicate the orientation or positional relationship based on the appendix. Figure 1The orientation or positional relationship shown is for the purpose of describing the present invention only, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0019] Please refer to Figure 1-2 This utility model relates to a wear-resistant high-frequency shut-off ball valve, particularly suitable for high-frequency feed shut-off in a lithium carbonate downstream slurry dewatering centrifuge. The ball valve comprises a valve body 1, two annular valve seats 3 disposed on the inner wall of the valve body 1, a ball 2 supported between the two annular valve seats 3, and a valve stem 4 connected to the top of the ball 2. The ball 2 is characterized by having a 316 stainless steel metal base and a tungsten carbide coating on its surface; an annular anti-wear groove 31 is provided on the inner wall of the valve body 1, and the annular valve seats 3 are installed within the annular anti-wear groove 31; a packing layer 5 is also provided on the inner wall of the valve body 1, the packing layer 5 being made of polytetrafluoroethylene or graphite. The valve body 1 is cast from ASTM A351 standard CF8M stainless steel, with an inlet and outlet diameter of DN80. The ball 2, with a base material of 316 stainless steel, is machined into a spherical shape by a CNC lathe and then surface-treated in a vacuum plasma spraying equipment. The specific process is as follows: First, the surface of the sphere is roughened by sandblasting with 24-mesh brown corundum sand, and then tungsten carbide powder with a particle size of 15-45μm is sprayed under argon protection. The valve body 1 is equipped with a packing layer 5. The material of the packing layer 5 is preferably polytetrafluoroethylene (PTFE) or graphite, both of which have good chemical corrosion resistance and thermal conductivity.

[0020] The annular anti-wear groove 31 has a depth of 1.5mm and a width of 2mm. The annular valve seat 3 is made of wear-resistant ceramic material, and its mating surface with the valve body 1 is machined with an annular anti-wear groove 31. The annular anti-wear groove 31 has a depth of 1.5mm ± 0.05mm and a width of 2.0mm ± 0.1mm. This annular anti-wear groove 31 makes the annular valve seat 3 and the valve body 1 fit more tightly. The ball 2 is floating and rotating inside the valve body 1 by the rotational force of the valve stem 4. During the rotation, because the slurry will seep into the bottom of the annular valve seat 3, the ball 2 and the valve body 1, the bottom of the valve body 1 is subjected to uneven force from the ball 2, which can easily cause wear on the valve body 1, the ball 2 and the annular valve seat 3. In this embodiment, the ceramic ball 2 is replaced with a metal-based ball, and a tungsten carbide coating is sprayed onto the surface of the metal-based ball, enabling the ball 2 to withstand high-frequency torque impacts. The annular anti-wear groove on the inner wall of the valve body 1 allows the annular valve seat 3 and the valve body 1 to fit more tightly, thereby compensating for wear caused by uneven rotation of the ball 2. The packing layer 5 reduces the corrosion of the inner wall of the valve body 1 by corrosive slurry. Therefore, the metal ball 2 with tungsten carbide coating, the annular anti-wear groove 31, and the packing layer 5 can solve the internal leakage caused by uneven wear of the ball 2 and eliminate the effect of one-sided scoring of the valve body 1 during the rotation of the ball 2.

[0021] The inner surface roughness Ra of the flow channel of valve body 1 is 0.6 μm, and the clearance between the flow channel of valve body 1 and ball 2 is 0.8 mm. To allow the ball to rotate freely, the inner cavity flow channel of valve body 1 is precision machined, with the inner surface roughness controlled to Ra = 0.6 μm. This value is obtained by averaging five measurement points evenly distributed along the flow channel axis using a portable surface roughness meter. The clearance between the flow channel and ball 2 is designed to be 0.8 mm; this dimension ensures the free rotation of the ball while preventing lithium carbonate slurry particles from entering the sealing area.

[0022] The valve stem 4 and the ball 2 are connected by an integrated short-shaft structure. To prevent lithium carbonate slurry from seeping into the gap and hardening and accumulating, increasing the rotational resistance of the ball, and causing the ceramic ball to break or the sealing surface to wear unevenly, the valve stem 4 and the ball 2 are designed to be connected by an integrated short-shaft structure. This structure is achieved through the following process: A 40mm diameter 316 stainless steel bar is selected, and the valve stem body 41 and the ball connection end 42 are simultaneously machined on a CNC lathe. The length of the ball connection end 42 is L = 18mm. The ball 2 and the ball connection end 42 adopt a transition fit method, and a permanent connection with an interference of 0.03mm is achieved during assembly through a 200℃ heat fitting process. The connection uses a large arc transition with R = 12mm, and the arc surface smoothly connects with the inner wall of the ball channel 21, thereby avoiding right-angle material accumulation.

[0023] The tungsten carbide coating thickness is 5±0.2mm. The tungsten carbide coating is applied in three coats, each coat being 1.7mm thick, for a total thickness of 5.0mm±0.2mm. An ultrasonic thickness gauge is used to measure the thickness at eight points evenly distributed on the equatorial surface of the sphere.

[0024] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A wear-resistant high-frequency cut-off ball valve, comprising a valve body (1), two annular valve seats (3) arranged on the inner wall of the valve body (1), a ball (2) supported between the two annular valve seats (3), and a valve stem (4) connected to the top of the ball (2), characterized in that, The ball (2) is a 316 stainless steel metal substrate, and the surface of the ball (2) is coated with tungsten carbide; the inner wall of the valve body (1) is provided with an annular anti-wear groove (31), and the valve seat (3) is installed in the annular anti-wear groove (31); the inner wall of the valve body (1) is also provided with a packing layer (5), and the material of the packing layer (5) is polytetrafluoroethylene or graphite.

2. The wear-resistant high-frequency shut-off ball valve according to claim 1, characterized in that, The annular anti-wear groove (31) has a groove depth of 1.5 mm and a groove width of 2 mm.

3. The wear-resistant high-frequency shut-off ball valve according to claim 1, characterized in that, The inner surface roughness of the valve body (1) flow channel is Ra=0.6μm, and the clearance between the valve body (1) flow channel and the ball (2) is 0.8mm.

4. The wear-resistant high-frequency shut-off ball valve according to claim 1, characterized in that, The valve stem (4) and the ball (2) are connected by an integrated short shaft structure.

5. The wear-resistant high-frequency shut-off ball valve according to claim 1, characterized in that, The thickness of the tungsten carbide coating is 5±0.2 mm.

Images