Fixed ball valve structure for pulverized coal conveying of coal gasification device

Abstract

The utility model discloses a pulverized coal conveying fixed ball valve structure for a coal gasification device, which relates to the technical field of valves and comprises a valve body, valve seats, a valve rod and a ball body, a flowing channel is arranged in the ball body, the valve seats are arranged at two ends of the ball body along the flowing channel, elastic pre-tightening pieces are arranged on the valve seats at two ends, and shaft handles are arranged at the upper end and the lower end of the ball body. The upper-end shaft handle is provided with an opening, the valve rod enters the opening and is connected with the upper-end shaft handle through a fixing pin, the upper-end shaft handle and the lower-end shaft handle are both connected with supporting plates and matched with the valve body through the supporting plates, and the supporting plates and the shaft handles are arranged in a centering mode. According to the utility model, through bidirectional sealing, the sealing performance and the structural stability are improved, the stress is optimized, the torque is reduced to resist high-pressure working conditions, the vibration resistance and the wear resistance are improved, the operation cycle cost is reduced, and the service life is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of valve technology, and more specifically, to a fixed ball valve structure for conveying pulverized coal in a coal gasification unit. Background Technology

[0002] With the rapid development of coal gasification and coal chemical technologies, the high-pressure, high-temperature, and high-solids-content media conditions in processes such as coal-to-oil, coal-to-gas, and coal-to-olefins place stringent requirements on core equipment. Valves used in hopper systems and pulverized coal conveying systems face technical challenges: firstly, safety production pressures, as the flammable and explosive nature of pulverized coal can lead to safety accidents, creating an urgent need for highly reliable, zero-leakage valves; secondly, energy efficiency and cost control, as the high frequency of system opening and closing operations results in high valve energy consumption, significant particulate wear during valve use, frequent maintenance, short lifespan, and high operating costs. Therefore, the industry urgently needs to reduce the life-cycle cost of valves.

[0003] The following problems exist in the application of existing floating ball valves: 1. High-pressure seal failure: Under large-diameter and high-pressure (Class 600 / 100bar) conditions (NPS12 (DN300) and above), the ball is displaced by the medium pressure, resulting in uneven contact of the sealing surface. API 598 standard tests show that its internal leakage rate is as high as 10% or more; 2. Particulate medium wear: The chrome-plated hardened sealing surface has a lifespan of less than 6 months under the erosion of coal dust particles (particle size ≤5mm). Frequent replacement leads to downtime losses. Moreover, the single-sided spring preloaded valve seat structure can only achieve one-way sealing. The valve's sealing performance is ensured by the force of the medium, i.e., the floating of the ball. Therefore, the valve seat on the sealing side is subjected to large compressive forces and frictional torque generated during opening and closing; 3. High-frequency operating torque and energy consumption: Under high pressure, the opening and closing torque of the floating ball valve is large, exceeding 5000 N·m. It requires matching with a large actuator (such as a large cylinder). Energy consumption accounts for 8%-12% of the total system energy consumption. Figure 1 As shown ( Figure 1 The left image shows a schematic diagram of the floating ball valve stem, and the right image is a cross-sectional view at point AA in the left image. In this structure, the stem and ball are connected by a crescent-shaped flat rectangular connection. The connection between the stem and ball is relatively weak, and the stem bears a large torque, making it prone to stress concentration and fracture when the opening and closing torque exceeds 5000 N·m. Although some improved designs use a double-seat fixed ball structure, it is prone to sealing failure due to particle jamming in solid media, and the superimposed preload of the double-seat springs significantly increases the opening and closing torque. Utility Model Content

[0004] To address this problem in practical applications, the purpose of this utility model is to propose a fixed ball valve structure for pulverized coal conveying in coal gasification units, achieving bidirectional zero-leakage sealing under high-pressure particulate media and overcoming the bottleneck of low torque durability under high cycle counts. The specific solution is as follows:

[0005] A fixed ball valve structure for conveying pulverized coal in a coal gasification unit includes a valve body, a valve seat, a valve stem, and a ball. The ball has a flow channel, and valve seats are provided at both ends of the flow channel. Each valve seat at both ends is provided with an elastic pre-tightening element. The ball has a shaft at both the upper and lower ends. The upper shaft has an opening, and the valve stem enters the opening and is connected to the upper shaft through a fixing pin. Both the upper and lower shafts are connected to support plates and cooperate with the valve body through the support plates. The support plates and shafts are centered.

[0006] Furthermore, both valve seats at both ends are provided with sealing rings on their outer periphery, and pressure rings are provided on the outer side of the sealing rings. The outer side of the pressure rings is pressed against by the elastic preload member, wherein the elastic preload member is a preload disc spring.

[0007] Furthermore, the valve stem is connected to the ball by four fixing pins, wherein the fixing pins are cylindrical pins.

[0008] Furthermore, the center lines of the support plate, the upper and lower end shafts of the ball, and the valve stem are located on the same axis.

[0009] Furthermore, the support plate is adapted to the outer wall of the valve body and the inner wall of the valve body.

[0010] Furthermore, a sliding bearing is provided on the upper end of the support plate and the ball, located between the valve stem and the valve body, and the sliding bearing is made of a high-molecular wear-resistant material.

[0011] Furthermore, the valve stem is made of precipitation-hardened stainless steel and has undergone surface hardening treatment.

[0012] Furthermore, a packing pressure plate, a packing sleeve, packing, and a stuffing box are also provided between the valve body and the valve stem.

[0013] Furthermore, the valve seat is made of F51 duplex steel.

[0014] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0015] (1) Significantly improved sealing reliability: The double-seat pre-tightening spring achieves bidirectional sealing function, eliminating the restriction of medium flow direction, so that valve installation does not need to rely on flow direction marking, reducing the risk of misinstallation on site, and the sealing pair wears evenly. Each opening and closing action causes a slight rotation of the ball to avoid excessive wear in some areas, and the pre-tightening force is stable and durable. After multiple opening and closing cycles, it still maintains a good sealing effect, effectively reducing the leakage rate and greatly improving the sealing life of traditional floating ball valves.

[0016] (2) Improved structural stability: The double valve seat enables the valve to withstand bidirectional pressure. The double valve seat spring preload and the medium pressure work together to form a dynamic compensation sealing band, which has high bidirectional sealing performance, prevents reverse leakage of the medium, and ensures the safe and stable operation of the production system.

[0017] (3) Optimized stress and improved deformation resistance: The ball adopts a positioning structure with upper and lower shafts and a support plate set in the center to evenly distribute the medium load to the ball, valve stem and valve body. The ball is in a stable position, reducing the amount of ball floating deformation. Even in high pressure and large diameter scenarios, it can withstand impact and maintain a precise assembly state, ensuring reliable valve operation in the long term and reducing the risk of sealing failure due to structural deformation. In addition, the symmetrical force design of the double valve seat eliminates the concentration of single-sided extrusion stress and improves the deformation resistance.

[0018] (4) Improve vibration and wear resistance: The fixed ball is stable and immobile. With precise machining and matching bearings, vibration transmission is reduced. Friction is concentrated in the preset small rotation range, wear is controllable, and the service life of the sealing pair and the overall valve is extended to meet the requirements of long-term stable operation of the device.

[0019] (5) Reduce torque and improve cost performance: The torque of a fixed ball valve increases relatively slowly. Under high pressure and large diameter conditions, the torque advantage of a fixed ball valve is more obvious. Moreover, due to the small torque, the required actuator size is small, which reduces the overall procurement cost of the valve. The smaller actuator makes on-site installation more convenient and reduces on-site energy damage. Attached Figure Description

[0020] Figure 1 This is a schematic diagram illustrating the structure of a floating ball valve stem in the prior art;

[0021] Figure 2 This is an overall schematic diagram of an embodiment of the present utility model;

[0022] Figure 3 This is a schematic diagram showing the connection between the valve seat and the valve body in an embodiment of this utility model;

[0023] Figure 4 This is a schematic diagram showing the structure of the valve stem and its upper pin hole in an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the structure of the sphere in an embodiment of this utility model;

[0025] Figure 6 This is a schematic diagram of the support plate in an embodiment of the present invention;

[0026] Figure 7 This is a schematic diagram illustrating the structure of hardened valve stem surface in an embodiment of this utility model.

[0027] Reference numerals in the attached drawings: 1. Main valve body; 2. Secondary valve body; 3. Valve seat; 4. Valve stem; 5. Ball; 6. Packing gland; 7. Packing sleeve; 8. Packing; 9. Stuffing box; 10. Sealing ring; 11. Elastic preload; 12. Pressure ring; 13. Adjusting shim; 14. Fixing pin; 15. Upper shaft handle; 16. Lower shaft handle; 17. Support plate; 18. Sliding bearing; 19. Pin hole. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0029] like Figure 2 As shown, a fixed ball valve structure for conveying pulverized coal in a coal gasification unit is an improvement on the floating ball valve structure. It includes a valve body, a valve seat 3, a valve stem 4, and a ball 5. The valve body consists of a main valve body 1 and a secondary valve body 2, which are fixedly connected and each has a valve body cavity (not shown in the figure). The valve seat 3 and the ball 5 are both located in the valve body cavity. The valve stem 4 is connected to the ball 5 and placed on the valve body. A packing pressure plate 6, a packing sleeve 7, a packing 8, and a packing gland 9 are also provided between the valve body and the valve stem 4.

[0030] The ball 5 has a flow channel (not shown in the figure), and valve seats 3 are provided at both ends of the flow channel. Each valve seat 3 has a sealing ring 10 and an elastic preload element 11. Both valve seats 3 can maintain a seal under the action of the sealing ring 10, achieving bidirectional sealing of the fixed ball valve. Simultaneously, the elastic preload element 11 on both valve seats 3 provides preload force, ensuring that the ball 5 and valve seats 3 always have a preload force regardless of temperature and pressure changes, keeping the valve seats 3 tightly against the ball 5 and ensuring the valve's sealing performance. Furthermore, since the structure of the valve seats 3 is identical at both ends, there are no directional requirements during installation. Compared to existing floating ball valves with unidirectional sealing that require attention to reverse installation, the fixed ball valve of this application has greater versatility, lower torque, and longer service life.

[0031] Specifically, in one possible embodiment, combining Figure 3 As shown, sealing rings 10 are provided on the outer periphery of both valve seats 3, and pressure rings 12 are provided on the outer side of the sealing rings 10. The outer side of the pressure rings 12 is pressed by an elastic pre-tightening member 11, wherein the elastic pre-tightening member 11 is a pre-tightening disc spring.

[0032] Furthermore, to further improve the sealing performance, an additional sealing ring 10 can be provided on the outside of the pressure ring 12, and an adjusting pad 13 can be provided outside the sealing ring 10. At this time, the elastic pre-tightening member 11 will press the adjusting pad 13 against the pressure ring 12.

[0033] Because the connection between the valve stem and the ball of the floating ball valve is a crescent-shaped flat square (see...) Figure 1 The connection between the valve stem and the ball is relatively weak, and the valve stem is subject to a large torque, making it prone to breakage.

[0034] Therefore, return Figure 2 Simultaneously combined Figure 4 , Figure 4 The left-hand diagram shows the structure of the valve stem, and the right-hand diagram is a cross-sectional view at point BB in the left-hand diagram. In this application, the valve stem 4 is connected to the ball 5 via a fixing pin 14. Specifically, in one possible embodiment, four pin holes 19 (not shown in the figure) are evenly distributed around the end of the valve stem 4 facing the ball 5. The fixing pin 14 is a cylindrical pin, which enters the pin holes 19 from the ball 5 to connect the valve stem 4 and the ball 5. At this time, the torsional stress borne by the valve stem 4 during the opening and closing process is changed to compressive stress, resulting in better stress distribution, a larger contact area, and no damage to the strength of the valve stem 4, thus ensuring the service life of the valve.

[0035] At the same time, combined Figure 5 The ball 5 has a handle at both the upper and lower ends. The upper handle 15 has an opening. The valve stem 4 enters the opening and is connected to the upper handle 15 through a fixing pin 14, which can improve the connection strength between the valve stem 4 and the ball 5.

[0036] Both the upper and lower end shafts are connected to support plates 17 and cooperate with the valve body via the support plates 17. The center lines of the support plate 17, the upper end shaft 15 of the ball 5, the lower end shaft 16, and the valve stem 4 are located on the same axis, meaning the support plate 17 is centered on the ball 5 and the valve stem 4. Specifically, in conjunction with... Figure 6 The support plate 17 has a through hole (not shown in the figure) in the middle position along its vertical direction for the upper and lower end shafts of the ball 5 to pass through; the outer wall of the support plate 17 facing the valve body is adapted to the inner wall of the valve body, and both have an arc-shaped surface structure.

[0037] In this application, the ball 5 adopts a connection structure that combines the upper and lower end shafts with the support plate 17. At this time, the force of the medium acting on the ball 5 is transmitted to the support plate 17, which can better protect the valve stem 4. The valve is only subjected to torsional stress during the opening and closing process, which better ensures the service life of the valve.

[0038] Meanwhile, the ball 5 and the valve stem 4 are connected by a cylindrical pin and are positioned in conjunction with the support plate 17 and the valve body. Compared with the existing floating ball valve, this structure can not only better ensure the alignment of the ball 5 and the valve stem 4, but also greatly improve the connection strength between the valve stem 4 and the ball 5, avoiding the adverse effects of valve stem 4 being strained or torque being increased, thus ensuring the performance of the valve.

[0039] Furthermore, returning to Figure 2A sliding bearing 18 is provided on the support plate 17 and the upper end of the ball 5, located between the valve stem 4 and the valve body. The sliding bearing 18 is made of high polymer wear-resistant material to reduce the opening and closing torque of the valve.

[0040] like Figure 7 As shown, the valve stem 4 is made of precipitation-hardened stainless steel and has undergone surface hardening treatment to improve its wear resistance and extend the service life of the valve.

[0041] To facilitate uniform replacement, in one possible embodiment, the valve body is manufactured to match the dimensions of the ball 5 and the valve seat 3, with a uniform depth. At the same time, the diameter of the ball 5 and the length of the valve seat 3 are all manufactured with a uniform diameter. In this embodiment, the diameter of the ball 5 is preferably 470mm, and the length of the valve seat 3 is preferably 5mm, which facilitates subsequent stockpiling and replacement.

[0042] Furthermore, the valve seat 3 is made of F51 high-strength duplex steel. By comparing the F51 duplex steel material used in this application with F316 steel material, the tensile strength, yield strength, elongation, reduction of area, and hardness data of the valve seat 3 are obtained, as shown in Table 1.

[0043] Table 1

[0044]

[0045] As shown in Table 1, after the material of the valve seat was changed, its tensile strength and yield strength were greatly improved, which can better meet the requirements of the working conditions.

[0046] This application improves the structure of the floating ball valve used for pulverized coal conveying in coal gasification units to a fixed ball valve structure, which solves the defects of existing floating ball valves such as insufficient sealing, severe wear, and high energy consumption, meets the current needs of the industry, and contributes to the development of the industry.

[0047] The above description is merely a preferred embodiment of this utility model. The protection scope of this utility model is not limited to the above embodiments. All technical solutions falling within the scope of this utility model's concept are protected. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of this utility model should also be considered within the protection scope of this utility model.

Claims

1. A fixed ball valve structure for conveying pulverized coal in a coal gasification unit, comprising a valve body, a valve seat, a valve stem, and a ball, characterized in that, The ball has a flow channel inside, and valve seats are provided at both ends of the flow channel. Each valve seat at both ends is provided with an elastic pre-tightening element. The ball has a shaft at both the upper and lower ends. The upper shaft has an opening. The valve stem enters the opening and is connected to the upper shaft through a fixing pin. Both the upper and lower shafts are connected to support plates and cooperate with the valve body through the support plates. The support plates are centered with the shafts.

2. The fixed ball valve structure for conveying pulverized coal in a coal gasification unit according to claim 1, characterized in that, Both ends of the valve seat are provided with sealing rings on their outer periphery, and a pressure ring is provided on the outside of the sealing ring. The outside of the pressure ring is pressed against by the elastic pre-tightening member, wherein the elastic pre-tightening member is a pre-tightening disc spring.

3. The fixed ball valve structure for pulverized coal conveying in a coal gasification unit according to claim 1, characterized in that, The valve stem is connected to the ball by four fixing pins, wherein the fixing pins are cylindrical pins.

4. The fixed ball valve structure for pulverized coal conveying in a coal gasification unit according to claim 1, characterized in that, The center lines of the support plate, the upper and lower end shafts of the ball, and the valve stem are all on the same axis.

5. The fixed ball valve structure for conveying pulverized coal in a coal gasification unit according to claim 1, characterized in that, The support plate is aligned with the outer wall of the valve body and fits into the inner wall of the valve body.

6. The fixed ball valve structure for conveying pulverized coal in a coal gasification unit according to claim 1, characterized in that, The support plate and the upper end of the ball are provided with a sliding bearing located between the valve stem and the valve body, and the sliding bearing is made of a high-molecular wear-resistant material.

7. The fixed ball valve structure for conveying pulverized coal in a coal gasification unit according to claim 1, characterized in that, The valve stem is made of precipitation-hardened stainless steel and has undergone surface hardening treatment.

8. The fixed ball valve structure for conveying pulverized coal in a coal gasification unit according to claim 1, characterized in that, The valve body and valve stem are also provided with a packing pressure plate, a packing sleeve, packing, and a stuffing box.

9. The fixed ball valve structure for conveying pulverized coal in a coal gasification unit according to claim 1, characterized in that, The valve seat is made of F51 duplex steel.

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