High temperature butterfly valve and its cooling method

Abstract

The present application relates to high temperature butterfly valve and its cooling method. The high temperature butterfly valve, including valve body, valve plate, valve stem, valve seat and actuator, the valve plate and valve stem have hollow structure with each other, the hollow structure has or connects the import and export of cooling medium. The present application solves the technical problem that the butterfly valve cannot be used in high temperature occasions, avoids many disadvantages of using plug valve under the same working condition, simplifies the structure, reduces the cost, and meets the production and use requirements of many enterprises.

Description

Technical Field

[0001] This invention relates to high-temperature butterfly valves and their cooling methods. Background Technology

[0002] Butterfly valves are commonly used in industries such as petroleum, chemical, power, and metallurgy. For butterfly valves designed for temperatures above 1050℃, the mechanical strength of the metal material is particularly low at this temperature. When the butterfly valve is large, the self-weight load of the internal valve plate, stiffeners, and shaft will cause the material stress to exceed the allowable stress at this temperature. In addition, the gas pressure inside the butterfly valve will further exceed the allowable stress. Therefore, flue butterfly valves are usually not used at such high temperatures; instead, slide gate valves are used.

[0003] For example, Metso Corporation in the United States uses a slide gate valve and the following corresponding measures to solve the problem of high temperature resistance of materials: the valve body is lined with insulation, the valve plate uses an interconnected pipe array as a skeleton, the pipe array is welded with insulation nails, the pipe array is covered with high temperature castable, and after curing and drying, the valve plate is formed. In order to prevent the pipe array from overheating, cooling water is circulated inside the pipe array during use. This structure solves the problem of high temperature resistance of metal materials in high temperature environments. Its shortcomings are: 1. It requires cooling water; if the water supply is interrupted, the butterfly valve may fail due to overheating; 2. It requires demineralized water; otherwise, scale may easily form inside the pipe or block the pipe; 3. If a water-cooling system is used, antifreeze insulation or circulating water measures are required; 4. It occupies a large space; 5. It has a long opening and closing time; 6. To avoid flash explosions or fires caused by the valve's inability to open and close properly in a faulty state, a reliable opening and closing system is required to ensure system safety, which significantly increases the manufacturing and maintenance costs of the entire valve system; 7. Without special waterproofing measures, it is difficult to ensure a seal at the valve plate inlet and outlet. Rainwater entering the valve body can react with sulfur-containing flue gas and damage subsequent production equipment.

[0004] For example, when using slide gate valves, some domestic companies address the high-temperature resistance issue of materials by making the valve plate into a box structure, covering the part of the valve plate in contact with the medium with high-temperature resistant insulation material. When the butterfly valve is closed, the opening of the box is located outside the valve body, and the box-shaped valve plate is exposed to the atmosphere, thus achieving cooling of the valve plate. Its advantages are simple structure and low cost; however, it also suffers from the shortcomings or potential hazards mentioned in points 5, 6, and 7 of the Metso slide gate valve described above.

[0005] The drawbacks of using slide gate valves in high-temperature applications have plagued many companies for years and have become a problem that urgently needs to be solved in this field. Summary of the Invention

[0006] In order to solve the above-mentioned problems in the existing technology, the present invention aims to provide a high-temperature butterfly valve or a high-temperature or ultra-high-temperature flue butterfly valve for use in larger diameter flues, so as to meet the practical needs of many enterprises.

[0007] The technical solution of this invention is implemented as follows: A high-temperature butterfly valve includes a valve body, a valve plate, a valve stem, a valve seat, and an actuator; the valve plate and the valve stem have a hollow structure that is interconnected, and the hollow structure has an inlet and an outlet for a cooling medium, or is connected to them.

[0008] Specifically, the valve stem is a hollow tube, with its two ends connected to a first inlet and a second outlet of cooling medium outside the valve plate, respectively. The middle portion of the valve stem penetrates the hollow cavity of the valve plate, and a second inlet and a first outlet of cooling medium are formed on the middle tube wall to connect the hollow tube of the valve stem with the hollow cavity of the valve plate. A sealing plate is provided between the second inlet and the first outlet. Further, the second inlet and the first outlet are located close to the first inlet and the second outlet, respectively, and are close to the inner wall of the valve plate corresponding to the valve stem's entry and exit points. Preferably, the valve stem axis is parallel to the surface of the valve plate.

[0009] The second inlet and the first outlet are through holes opened on the valve stem wall. The second inlet is close to the first inlet, and the first outlet is close to the second outlet. A sealing plate is fixed between the second inlet and the first outlet of the hollow tube to separate the inlet and the outlet. The external cooling medium enters the hollow inner cavity of the valve plate from the first inlet of the valve stem through the second inlet, and is led out from the first outlet of the valve stem through the second outlet to the outside of the butterfly valve.

[0010] Furthermore, the hollow pipe section of the valve stem corresponding to the second inlet and the first outlet is provided with a pipe wall reinforcement structure; specifically, the reinforcement structure is arranged axially and is a plate, pipe or structural component; for example, the reinforcement structure is a hub-shaped reinforcement inserted into the valve stem, which can be set in the valve stem at the inlet and outlet positions on the radial end face of the valve stem and transition fit or interference fit with the valve stem, its axial length is greater than the diameter of the inlet and outlet, its two axial ends are symmetrical to the axis of the inlet and outlet, and its outer diameter is equal to the inner diameter of the valve stem; Alternatively, specifically, the valve stem comprises two coaxial hollow tube segments symmetrically fixed to both sides of the valve plate. The hollow tube segments of the valve stem are respectively connected to the hollow cavity of the valve plate, and the openings of the two hollow tube segments away from the valve plate are respectively connected to the inlet and outlet of the cooling medium. External cooling medium enters the hollow cavity of the valve plate through the valve stem inlet and exits through the valve stem outlet to the outside of the butterfly valve. Preferably, the axes of the two coaxial hollow tube segments of the valve stem are parallel to the surface of the valve plate.

[0011] More preferably, a baffle plate is provided within the hollow cavity of the valve plate. The baffle plate is disposed throughout the hollow cavity of the valve plate to guide the flow of the cooling medium and minimize dead zones.

[0012] Furthermore, a heat-insulating lining is fixed inside the valve body; and / or a heat-insulating layer or a thermal insulation layer is covered on the outer surface of the valve plate.

[0013] Furthermore, one or more temperature sensors are provided within the hollow cavity of the valve plate.

[0014] Furthermore, to prevent the valve seat from yielding or creeping at high temperatures when there is a heat insulation lining in the valve body, the valve seat fixed on the valve body is divided into N circumferentially distributed segments, with an expansion gap between adjacent segments; in order to cover the axial and radial gaps left by the expansion gaps, a plate is provided above or below the expansion gap to cover the corresponding gaps; wherein, N≥2.

[0015] Furthermore, the valve body can be externally connected to a chimney that is perpendicular to the ground. The upper end of the chimney is higher than the upper end of the valve body, and the lower opening of the chimney is connected to the second outlet of the valve stem via a flexible hose.

[0016] Furthermore, an umbrella-shaped rain cap is fixed to the outlet end above the chimney; Furthermore, a blower is connected to the outside of the valve body, and a section of duct is connected to the outlet of the blower. The other end of the duct is connected to a pipe with an inlet on its radial end face. One end of the valve stem protrudes from the actuator and is connected to the pipe via a flexible hose. The axis of the pipe is nearly horizontal, and a one-way valve is installed inside its inlet end. To facilitate automatic opening of the one-way valve, the one-way valve is installed at an angle inward into the pipe in a direction perpendicular to the ground. The valve plate of the one-way valve is located at the bottom, and the valve plate rotates up and down to open and close. When the blower is not working, the valve plate of the one-way valve opens automatically by gravity.

[0017] Furthermore, the high-temperature butterfly valve may also include a controller, which includes a memory and a processor, with a computer program stored in the memory; correspondingly, the temperature sensor and blower, etc., are connected to the controller, and the processor executes the program to perform the following steps: The temperature data inside the valve plate is collected, and the blower is turned on and off according to the temperature setting.

[0018] This invention also discloses a method for cooling the high-temperature butterfly valve: Cooling medium enters the hollow structure of the valve plate and valve stem through the inlet, cooling the valve plate and valve stem, and then exits the butterfly valve through the outlet; furthermore, the cooled butterfly valve's temperature is lower than its maximum allowable temperature. The maximum allowable temperature of the butterfly valve is given based on design calculations and / or simulation calculations.

[0019] The cooling medium is air, water, or heat transfer oil drawn from the outside.

[0020] To cool the valve body, it can also be made into a jacketed structure with an inlet and an outlet on the outside of the jacket, and a cooling medium flowing through the inside of the jacket.

[0021] This invention utilizes the principle of air cooling by incorporating a hollow cavity within the valve plate. When the gas inside is heated, it automatically convects with the surrounding air. This invention improves cooling efficiency by increasing the airflow within the hollow cavity. The outlet at the top of the pipe, which replaces the chimney, is under negative pressure compared to the inlet on the valve stem, further increasing airflow. When natural convection or the aforementioned structure is insufficient, for example, by using a temperature sensor signal to start the blower, the blower's start and stop can be controlled by setting upper and lower temperature limits, thus achieving automated control and energy efficiency. When the blower is on, the one-way valve closes under air pressure. When the blower stops, the one-way valve opens by its own weight to ensure natural airflow.

[0022] The structure when water or heat transfer oil is used as the cooling medium is common technical knowledge in this field and will not be elaborated here.

[0023] Compared with the prior art, the present invention has the following technical effects: 1. Since the valve plate has a hollow inner cavity, by introducing a cooling medium into the cavity, the global problem that butterfly valves cannot be used in situations with particularly high temperatures has been effectively solved, thereby meeting the needs of many enterprises.

[0024] 2. It avoids many of the drawbacks of using slide gate valves as listed above.

[0025] 3. Compared to slide gate valves, it simplifies the structure, reduces costs, and lowers future maintenance costs.

[0026] 4. The valve stem is inside the cavity of the valve plate. When the inner cavity is cooled, the valve stem is cooled at the same time, and the valve stem does not need to be insulated separately.

[0027] This invention is applicable to various types of butterfly valves, including four-bar butterfly valves, and is especially suitable for high-temperature flue applications. Attached Figure Description

[0028] Figure 1 The front view of Embodiment 1 according to the present invention is as follows: Figure 2 for Figure 1 AA section view; Figure 3 The front view of Embodiment 2 according to the present invention: Figure 4 for Figure 3 BB cross-sectional view; Figure 5 A partial cross-sectional view of the valve stem and hub-shaped reinforcement according to Embodiment 1 of the present invention: Figure 6 for Figure 5 CC section view: In the diagram: 1. Temperature sensor; 2. Valve plate; 3. Baffle plate; 4. Valve seat; 5. Valve body; 6. Shaft seal stuffing box; 7. Actuator; 8. Hose a; 9. Pipe a; 10. Check valve; 11. Blower; 12. Air duct; 13. Thermal insulation lining; 14. Sealing plate; 15. Valve stem; 16. Hose b; 17. Pipe b; 18. Umbrella-shaped rain cap; 19. Insulation layer; 20. Hollow tube section a of valve stem; 21. Hollow tube section b of valve stem; 22. Hub-shaped reinforcing member I1; First inlet I2, I2′; Second inlet E1, E1′; First outlet E2; Second outlet E3; Pipe outlet. Implementation

[0029] The present invention will now be described in more detail with reference to the accompanying drawings. Example

[0030] A high-temperature butterfly valve, such as Figure 1 , Figure 2 As shown, the butterfly valve includes a valve body 5, a valve plate 2, a valve stem 15, a valve seat 4, a shaft seal stuffing box 6, and an actuator 7. The valve plate 2 has a hollow cavity, and the valve stem 15 is a hollow tube with its axis parallel to the surface of the valve plate 2. The valve stem 15 passes through the hollow cavity of the valve plate 2, and its two ends have a first inlet I1 and a second outlet E2 for the external cooling medium, respectively. The two radial end faces of the valve stem 15 located in the hollow cavity of the valve plate 2 are respectively provided with a second inlet I2 (I2′) and a first outlet E1 (E1′) for the external cooling medium. 2′) The first outlet E1 (E1′) is close to the first inlet I1 and the second outlet E2 respectively, and is also close to the inner wall of the corresponding cavity in the hollow cavity of the valve plate; and a sealing plate 14 is fixed on the hollow tube of the valve stem between the second inlet I2 (I2′) and the first outlet E1 (E1′) to separate the inlet and outlet. The external cooling medium enters the hollow cavity of the valve plate 2 from the first inlet I1 of the valve stem 15 through the second inlet I2 (I2′), and is led out from the first outlet E1 (E1′) of the valve stem 15 through the second outlet E2 to the outside of the butterfly valve; Furthermore, a reinforcing structure is provided inside the valve stem 15 corresponding to the positions of the second inlet I2 (I2′) and the first outlet E1 (E1′); as... Figure 1 , Figure 2 and Figure 6As shown, it can be a hub-shaped reinforcing member 22 inserted into the valve stem 15, whose axial length is greater than the diameter of the corresponding inlet I2 (I2′) and outlet E1 (E1′), and whose two axial ends are symmetrical to the axes of the inlet I2 (I2′) and outlet E1 (E1′), respectively. Its outer diameter is equal to the inner diameter of the valve stem 15 and the two are transition fit or interference fit. Example

[0031] A high-temperature butterfly valve, such as Figure 3 , Figure 4 As shown, the valve includes a valve body 5, a valve plate 2, a valve stem, a valve seat 4, a shaft seal stuffing box 6, and an actuator 7. The valve plate 2 has a hollow cavity. The valve stem includes two coaxial hollow tube sections 20 and 21, which are symmetrically fixed on both sides of the valve plate 2 and respectively connected to the hollow cavity of the valve plate 2. Their axes are parallel to the surface of the valve plate 2, and the openings of the two hollow tube sections 20 and 21 away from the valve plate 2 are respectively the first inlet I1 and the second outlet E2 of the cooling medium. The cooling medium enters the hollow cavity of the valve plate from the first inlet I1 of the valve stem 20 and exits to the outside of the butterfly valve from the second outlet E2 of the valve stem 21.

[0032] Specifically, for the aforementioned high-temperature butterfly valve, the cooling medium can be air or water drawn from the outside, or heat transfer oil.

[0033] Furthermore, a baffle plate 3 can also be provided in the hollow cavity of the valve plate 2. It is disposed in the entire hollow cavity of the valve plate 2 to guide the flow of the cooling medium and avoid dead zones as much as possible. A heat insulation lining 13 is fixed inside the valve body 5; The outer surface of the valve plate 2 is completely covered with a heat insulation layer or thermal insulation layer 19. The valve body 5 is externally connected to a pipe b17 that is fixed perpendicular to the ground to replace the function of a chimney. The pipe opening E3 above the pipe b17 is higher than the valve body 5, and the pipe opening below the pipe b17 is connected to the outlet E2 of the valve stem 15 or the hollow pipe section b21 of the valve stem through a hose b16. An umbrella-shaped rain cap 18 can be fixed above the outlet E3 of the pipe b17 that replaces the chimney function; The valve body 5 can be externally connected to a blower 11. The outlet of the blower 11 is connected to a section of duct 12. The other end of the duct 12 is connected to a pipe a9 with an inlet on the radial end face. One end of the valve stem 15 or the hollow pipe section a20 of the valve stem protrudes from the actuator 7 and is connected to the outlet of the pipe a9 through a flexible hose a8. The axis of the pipe a9 is nearly horizontal, and a one-way valve 10 is installed inside the inlet end of the pipe a9. To facilitate the automatic opening of the one-way valve 10, the one-way valve 10 is installed at an angle to the inside of the pipe 9 in a direction perpendicular to the ground, with the valve plate shaft of the one-way valve 10 at the bottom, and the valve plate of the one-way valve 10 rotates up and down to open and close; when the blower 11 is not working, the valve plate of the one-way valve 10 opens automatically by gravity; one or more temperature sensors 1 are fixed on the inner wall of the hollow cavity of the valve plate 2.

[0034] The temperature sensor 1 and blower 11 are connected to the controller (not shown in the figure) to enable the automatic start and stop of the blower and other equipment by computer program control according to the temperature setting.

[0035] To prevent the valve seat 4 from yielding or creeping at high temperatures when there is a heat insulation lining 13 inside the valve body 5, the valve seat 4 fixed on the valve body 5 is divided into N circumferentially distributed segments (N≥2, not shown in the figure), with an expansion gap between each adjacent segment; the gap amount is determined after calculation based on the design temperature; above or below the gap position between all valve seats 4, there is a plate to block the axial and radial gaps left by the gap between valve seats 4 (not shown in the figure).

[0036] Obviously, the above embodiments are only some embodiments of the present invention, and not all embodiments. Based on this, any technical solution obtained by those skilled in the art, within the scope of the technology disclosed in this invention, by making equivalent substitutions or modifications to the technical solutions and inventive concepts of the present invention without creative effort, should be covered within the protection scope of this invention.

Claims

1. A high-temperature butterfly valve, comprising a valve body, a valve plate, a valve stem, a valve seat, and an actuator; wherein the valve plate and the valve stem have a hollow structure that communicates with each other, and the hollow structure has an inlet and an outlet for a cooling medium, or is connected to the hollow structure; characterized in that: One or more temperature sensors are provided in the hollow cavity of the valve plate; The valve body is externally connected to a blower. The outlet of the blower is connected to a section of duct. The other end of the duct is connected to a pipe with an inlet on its radial end face. One end of the valve stem protrudes from the actuator and is connected to the pipe via a flexible hose. The axis of the pipe is nearly horizontal. A one-way valve is installed inside its inlet end. The one-way valve is installed at an angle in the pipe perpendicular to the ground. The valve plate of the one-way valve is located at the bottom. The valve plate of the one-way valve rotates up and down to open and close. When the blower is not working, the valve plate of the one-way valve opens automatically by gravity. The high-temperature butterfly valve includes a controller, which includes the temperature sensor and a blower connected to the controller; The controller includes a memory and a processor, wherein a computer program is stored in the memory; When the processor executes the program, it performs the following steps: Collect temperature data within the valve plate, and turn the blower on and off according to the temperature setting; The temperature of the butterfly valve after cooling is lower than its maximum allowable temperature; the maximum allowable temperature of the butterfly valve is given based on design calculations and / or simulation calculations.

2. The high-temperature butterfly valve as described in claim 1, characterized in that: The valve stem is a hollow tube, with its two ends connected to a first inlet and a second outlet of cooling medium outside the valve plate, respectively. The middle part of the valve stem penetrates the hollow cavity of the valve plate, and a second inlet and a first outlet of cooling medium are opened on the middle tube wall to connect the hollow tube of the valve stem with the hollow cavity of the valve plate. A sealing plate is provided between the second inlet and the first outlet.

3. The high-temperature butterfly valve as described in claim 2, characterized in that: The second inlet and the first outlet are located near the first inlet and the second outlet, respectively, and are each located near the inner wall of the valve plate corresponding to the valve stem entering and exiting the valve plate.

4. The high-temperature butterfly valve as described in claim 2, characterized in that: The valve stem has a pipe wall reinforcement structure in the hollow pipe section corresponding to the second inlet and the first outlet.

5. The high-temperature butterfly valve as described in claim 1, characterized in that: The valve stem includes two coaxial hollow tube sections, which are symmetrically fixed on both sides of the valve plate. The hollow tube sections of the valve stem are respectively connected to the hollow cavity of the valve plate, and the openings of the two hollow tube sections of the valve stem away from the valve plate are respectively connected to the inlet and outlet of the cooling medium.

6. The high-temperature butterfly valve as described in claim 1, characterized in that: The valve plate has a baffle plate inside its hollow cavity.

7. The high-temperature butterfly valve as described in claim 1, characterized in that: The valve body is fixed with a heat-insulating lining; and / or The valve plate is covered with a heat insulation layer or a thermal insulation layer.

8. The high-temperature butterfly valve as described in claim 1, characterized in that: The valve body is externally connected to a chimney that is perpendicular to the ground. The upper end of the chimney is higher than the upper end of the valve body. The pipe opening below the chimney is connected to the second outlet of the valve stem via a flexible hose. An umbrella-shaped rain cap is fixed to the outlet end above the chimney.

9. The high-temperature butterfly valve as described in claim 1, characterized in that: The valve seat is fixed on the valve body and is divided into N circumferentially distributed segments, with an expansion gap between adjacent segments; above or below the expansion gap, there is a plate to block the corresponding gap; wherein, N≥2.

10. A method for cooling a high-temperature butterfly valve as described in claim 1, characterized in that: The processor executes the program in memory to perform the following steps: Collect temperature data within the valve plate, and turn the blower on and off according to the temperature setting; The valve plate has a hollow cavity inside, where the gas will automatically convect with the outside air after being heated. The start and stop of the blower are controlled by setting upper and lower limits of temperature. When the blower is turned on, the valve plate of the one-way valve is closed under the action of air pressure. When the blower stops running, the valve plate of the one-way valve opens by its own weight to ensure natural air circulation. The temperature of the butterfly valve after cooling is lower than its maximum allowable temperature; the maximum allowable temperature of the butterfly valve is given based on design calculations and / or simulation calculations.

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