A butterfly valve sealing surface flushing device

Abstract

This invention provides an external butterfly valve sealing surface flushing device, including a valve body, a valve plate disposed within the valve cavity of the valve body, a valve shaft sleeved within the valve plate, a bushing disposed between the upper ends of the valve body and the valve shaft, a packing assembly disposed above the bushing, and the packing assembly being fastened to the end face of the valve body by a fixing assembly; a limiting assembly disposed between the lower ends of the valve body and the valve shaft, a sealing assembly disposed between the outer periphery of the valve plate and the valve body, a plane bearing disposed at the bottom of the valve shaft, a bottom flange disposed at the bottom of the valve body, the plane bearing and the bottom flange being fixed, and a flushing short connecting pipe disposed between the flange end of the valve body and the field pipeline, the flushing short connecting pipe having a closed welded chamber inside, the welded chamber having a row of oblique through holes, the axis of the oblique through holes facing the sealing surface of the valve body. This invention can overcome the problems of valve action jamming and substandard sealing performance under harsh working conditions, ensuring that the valve can maintain a good working condition for a long time in the delayed coking unit, and ensuring the safe and stable operation of the delayed coking unit.

Description

Technical Field

[0001] This invention relates to the field of fluid control valve technology, and in particular to an external butterfly valve sealing surface flushing device. Background Technology

[0002] Delayed coking units are one of the core components of heavy oil light processing in refineries. They can convert low-cost heavy oils such as vacuum residue and deoiled bitumen into high-value light oils such as gasoline, diesel, and wax oil, as well as petroleum coke. This is a key link for refineries to improve processing depth, optimize product structure, and enhance economic efficiency.

[0003] The delayed coking unit operates under harsh conditions. The feedstock oil temperature at the heater outlet reaches 480-520℃, and after entering the coking tower, it undergoes rapid vaporization and cracking. The coking tower experiences a cycle of "raw coke - cold coke - decoking," with the tower temperature repeatedly fluctuating between 500℃ and 100℃. The operating pressure of the heater system is approximately 1MPa-1.8MPa, while the pressure of the hydraulic decoking system reaches 12MPa-35MPa, resulting in large pressure fluctuations. Furthermore, the medium contains high sulfur, high nitrogen, and high residual carbon components, making it highly corrosive. The medium also carries solid impurities such as coke powder and coke particles, exhibiting strong scouring and abrasive properties. During shutdowns or low-load conditions, residual oil easily cokes in the valve cavity and valve stem gaps. Processes such as coke tower switching and decoking operations require frequent valve opening and closing within a short period, demanding rapid valve response and extremely high requirements for the sealing structure. Compared to ball valves and gate valves, the triple-eccentric hard-seal butterfly valve features a straight-through flow channel design. When fully open, its flow resistance coefficient is significantly lower than that of ball valves and gate valves. This reduces pressure loss during the transport of high-temperature oil and gas and high-pressure decoking water, lowers the operating load of heating furnaces and high-pressure water pumps, and results in significant energy savings. The triple-eccentric structure enables frictionless opening and closing between the butterfly plate and the valve seat. The low opening and closing torque meets the requirements of high-frequency opening and closing conditions such as coke tower switching and decoking branch reversal. It also offers advantages such as convenient maintenance and low overall cost. However, with existing sealed butterfly valves, the sealing surfaces between the butterfly plate and the valve seat are easily damaged by factors such as coke particle erosion or residual oil coking. The valve seat, sealing ring, and valve shaft are prone to damage. High temperatures and temperature changes in the unit can also cause the valve to jam, fail to operate, or fail to meet sealing performance standards, ultimately affecting the use of the unit and system safety, resulting in significant economic losses. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an external butterfly valve sealing surface flushing device. This device effectively solves problems such as valve jamming and substandard sealing performance caused by factors such as coke particle erosion, residual oil coking, and temperature fluctuations, ensuring that the valve maintains a good working condition in the delayed coking unit for a long time and guaranteeing the safe and stable operation of the unit.

[0005] The technical solution adopted in this invention is: An external butterfly valve sealing surface flushing device includes: a valve body; a valve plate is disposed within the valve cavity of the valve body; a valve shaft is sleeved within the valve plate; one end of the valve shaft extends outside the valve body; a bushing is disposed between the upper end of the valve body and the valve shaft; a packing assembly is disposed above the bushing; the packing assembly is fastened to the end face of the valve body by a fixing assembly; a limiting assembly is disposed between the lower end of the valve body and the valve shaft; a sealing assembly is disposed between the outer periphery of the valve plate and the valve body; a plane bearing is disposed at the bottom of the valve shaft; a bottom flange is disposed at the bottom of the valve body; the plane bearing and the bottom flange are fixed; a flushing short connector is disposed between the flange end of the valve body and the field pipeline; a closed welded chamber is disposed inside the flushing short connector; the welded chamber has a row of oblique through holes, the axis of which faces the sealing surface of the valve body.

[0006] Preferably, in the external butterfly valve sealing surface flushing device, the valve plate and valve shaft are connected in the valve cavity of the valve body via a flat key.

[0007] Preferably, in the external butterfly valve sealing surface flushing device, the valve plate and valve shaft are fixed by hexagonal head positioning bolts.

[0008] Preferably, in the external butterfly valve sealing surface flushing device, a graphite packing is provided at the bottom of the bushing, and the graphite packing and the bushing are arranged sequentially from bottom to top between the valve body and the upper end of the valve shaft.

[0009] Preferably, in the external butterfly valve sealing surface flushing device, the packing assembly includes, from bottom to top, a packing pad, graphite packing, a packing gland, and a packing pressure plate; the fixing assembly includes a fully threaded stud, a hexagonal nut, and a butterfly spring; the butterfly spring is provided on the packing pressure plate; and the packing pressure plate and the valve body are fastened to the valve body end face by the fully threaded stud and the hexagonal nut.

[0010] Preferably, in the external butterfly valve sealing surface flushing device, the limiting component includes a plane bearing, a pressure ring, and a split ring, which are arranged sequentially from top to bottom between the valve body and the lower end of the valve shaft.

[0011] Preferably, in the external butterfly valve sealing surface flushing device, the sealing assembly includes a first metal spiral wound gasket, a sealing ring, and a pressure ring. The sealing ring is provided on the outer periphery of the valve plate. The sealing ring is pressed onto the valve plate by the pressure ring and fastened by an internal hexagon screw. The first metal spiral wound gasket is provided between the sealing ring and the valve plate.

[0012] Preferably, in the external butterfly valve sealing surface flushing device: an adjusting shim is provided at the bottom of the planar bearing, the adjusting shim is provided between the bottom of the planar bearing and the bottom flange, a second metal spiral wound shim is provided between the bottom flange and the bottom of the valve body, and the planar bearing and the bottom flange are fastened to the bottom of the valve body by hexagonal head bolts.

[0013] Preferably, in the external butterfly valve sealing surface flushing device, a shut-off check valve is installed at the external interface of the flushing short pipe.

[0014] Preferably, in the external butterfly valve sealing surface flushing device, a flange spiral wound gasket is provided between the flushing short pipe, the valve body flange end, and the field pipeline. The flushing short pipe and the flange spiral wound gasket are installed between the valve body flange end and the field pipeline by pipe flange studs and nuts.

[0015] Preferably, in the external butterfly valve sealing surface flushing device, the oblique through hole of the welded chamber of the external flushing short circuit is located near the valve body and the sealing ring.

[0016] Advantages of this invention: (1) The external butterfly valve sealing surface flushing device of the present invention enters the flushing short pipe welding chamber through the external instrument air or flushing water connected to the inlet of the stop check valve. The oblique through hole of the welding chamber blows and flushes the valve seat sealing surface for cooling. During the valve opening and closing process, there may be a large temperature difference between the valve front and the valve back. The valve seat can be blown and flushed and cooled by the instrument air or flushing water in the flushing short pipe chamber, so that the temperature difference between the valve seat front and back is basically uniform. On the one hand, it avoids the decrease in the sealing fit between the butterfly plate and the valve seat due to the alternating temperature between the valve front and the valve back, which leads to sealing failure. On the other hand, it blows away the solid impurities such as residual oil, coke powder or colloid particles accumulated on the sealing surface, avoiding damage to the sealing surface due to solid impurities.

[0017] (2) In the external butterfly valve sealing surface flushing device of the present invention, the direction of the pipeline medium fluid is consistent with the direction of the flushing medium fluid. On the one hand, it is beneficial for the flushing medium to flush the valve seat sealing surface; on the other hand, when the valve is closed, the instrument air or flushing water continuously blows and flushes the medium at the inlet end, which can effectively prevent solid impurities such as residual oil, coke powder or colloids from accumulating in front of the valve and forming colloids or solid crystals that adhere to the valve body and valve seat, making them difficult to clean.

[0018] (3) The external butterfly valve sealing surface flushing device of the present invention has a flushing short pipe welded chamber oblique through hole set near the valve body and sealing ring, which can effectively blow and flush the sealing surface of the butterfly valve with small opening adjustment. On the one hand, it can avoid the material flow capacity reduction caused by material accumulation, which affects the valve adjustment performance; on the other hand, continuous blowing and flushing can effectively prevent solid impurities such as residual oil, coke powder or colloid particles attached to the valve shaft from entering the gap between the valve shaft and the valve body, which can lead to problems such as valve shaft damage or even jamming.

[0019] (4) The external butterfly valve sealing surface flushing device of the present invention has a flushing short pipe that is independently connected to the valve and pipeline, which not only effectively improves the service life of the valve, but also allows for online replacement and low maintenance costs.

[0020] (5) The external butterfly valve sealing surface flushing device of the present invention has a graphite packing at the valve body and bushing, which can effectively prevent solid impurities such as residual oil, coke powder or colloid particles from entering between the valve shaft and the bushing, avoiding damage to the valve shaft and bushing, and causing damage to the valve shaft or even jamming.

[0021] (6) The external butterfly valve sealing surface flushing device of the present invention uses a key connection between the valve shaft and the valve plate for transmission. On the one hand, it ensures the rigidity and strength of the valve shaft; on the other hand, the flat key is installed in the keyway with a certain gap in the height direction, so that the key has a certain expansion space under high temperature conditions, minimizing the deformation of the valve shaft; and it is also compatible with installation, disassembly and maintenance. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the external butterfly valve sealing surface flushing device of the present invention.

[0023] Figure 2 for Figure 1 AA section view.

[0024] Figure 3 for Figure 1 BB cross-sectional view.

[0025] Figure 4 This is a schematic diagram of the flushing short pipe of the present invention.

[0026] Figure 5 for Figure 2 A magnified view of part I. Detailed Implementation

[0027] The present invention will be further described below with reference to specific accompanying drawings and embodiments.

[0028] like Figures 1-5 An external butterfly valve sealing surface flushing device includes: a valve body 1, a valve plate 2 disposed inside the valve cavity of the valve body 1, a valve shaft 3 sleeved inside the valve plate 2, one end of the valve shaft 3 extending outside the valve body 1, a bushing 6 disposed between the upper ends of the valve body 1 and the valve shaft 3, a packing assembly disposed above the bushing 6, the packing assembly being fastened to the end face of the valve body 1 by a fixing assembly; a limiting assembly disposed between the lower ends of the valve body 1 and the valve shaft 3, a sealing assembly disposed between the outer periphery of the valve plate 2 and the valve body 1, a plane bearing 23 disposed at the bottom of the valve shaft 3, a bottom flange 26 disposed at the bottom of the valve body 1, the plane bearing 23 and the bottom flange 26 being fixed, a flushing short pipe 18 disposed between the flange end of the valve body 1 and the field pipeline, a closed welded chamber 29 disposed inside the flushing short pipe 18, the welded chamber having a row of oblique through holes 30, the axis of the oblique through holes 30 facing the sealing surface direction of the valve body 1.

[0029] The valve plate 2 and the valve shaft 3 are connected in the valve cavity of the valve body 1 by a flat key 16; the valve plate 2 and the valve shaft 3 are fixed by a hexagonal head positioning bolt 10.

[0030] The bottom of the bushing 6 is provided with a graphite packing 9, and the graphite packing 9 and the bushing 6 are arranged from bottom to top between the upper ends of the valve body 1 and the valve shaft 3.

[0031] The packing assembly includes, from bottom to top, a packing pad 7, a graphite packing 8, a packing gland 14, and a packing pressure plate 15. The fixing assembly includes a fully threaded stud 11, a hexagonal nut 12, and a butterfly spring 13. The butterfly spring 13 is installed on the packing pressure plate 15. The packing pressure plate 15 and the valve body 1 are fastened to the end face of the valve body 1 by the fully threaded stud 11 and the hexagonal nut 12.

[0032] The limiting assembly includes a plane bearing 20, a pressure ring 21, and a split ring 22, which are arranged sequentially from top to bottom between the lower end of the valve body 1 and the valve shaft 3.

[0033] The sealing assembly includes a first metal spiral wound gasket 17, a sealing ring 5, and a pressure ring 4. The sealing ring 5 is provided on the outer periphery of the valve plate 2. The sealing ring 5 is pressed onto the valve plate 2 by the pressure ring 4 and fastened by an internal hex screw 28. The first metal spiral wound gasket 17 is provided between the sealing ring 5 and the valve plate 2.

[0034] An adjusting shim 24 is provided at the bottom of the planar bearing 23. The adjusting shim 24 is located between the bottom of the planar bearing 23 and the bottom flange 26. A second metal spiral wound shim 25 is provided between the bottom flange 26 and the bottom of the valve body 1. The planar bearing 23 and the bottom flange 26 are fastened to the bottom of the valve body 1 by hexagonal head bolts 27.

[0035] The external interface of the flushing short connector 18 is equipped with a shut-off check valve 19; a flange spiral wound gasket is provided between the flushing short connector 18, the flange end of the valve body 1, and the field pipeline. The flushing short connector 18 and the flange spiral wound gasket are installed between the flange end of the valve body 1 and the field pipeline through pipe flange studs and nuts; the oblique through hole 30 of the welded chamber of the external flushing short connector 18 is located near the valve body 1 and the sealing ring 5.

[0036] The working process of this invention is as follows: like Figures 1-3As shown, after the butterfly valve is installed, counterclockwise rotation is the valve opening direction, and clockwise rotation is the valve closing direction. The medium flows through the valve via the flow channel, and enters the welded chamber of the flushing short pipe 18 through the inlet of the stop check valve 19 connected to external instrument air or flushing water. The oblique through hole of the welded chamber blows and flushes the sealing surface of the valve body 1, effectively reducing the temperature difference between the valve body 1 and the sealing ring before and after the valve. This avoids the valve jamming or sealing failure caused by the different thermal expansion of the valve body 1 and the sealing ring due to the temperature difference before and after the valve. The oblique through hole of the welded chamber of the flushing short pipe 18 is located near the valve body and the sealing ring 5, and the blowing medium continuously... The sealing surface and valve shaft 3 are purged and flushed. The purging medium can be air or water to prevent the medium from accumulating in the valve seat sealing surface and the gap between valve shaft 3 and valve body 1, which would reduce the valve's flow capacity, cause the sealing surface to be scratched and stuck, and lead to sealing failure. When the valve is closed, the air or flushing water continuously purges and flushes the medium at the inlet end, which can effectively prevent solid impurities such as residual oil, coke powder, or colloids from accumulating in front of the valve and forming gel-like or solid crystals that adhere to the valve body and valve seat and are difficult to clean. Graphite packing 9 is provided between valve body 1 and bushing 6, which can effectively prevent the medium from entering the gap between valve body 1 and bushing 6, and prevent the valve shaft 3 and bushing 6 from being scratched, which could lead to valve shaft scratching or even sticking.

[0037] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An external butterfly valve sealing surface flushing device, characterized in that: The valve body (1) includes a valve plate (2) inside its valve cavity. A valve shaft (3) is fitted inside the valve plate (2), with one end of the valve shaft (3) extending outside the valve body (1). A bushing (6) is provided between the upper ends of the valve body (1) and the valve shaft (3). A packing assembly is provided above the bushing (6), and the packing assembly is fastened to the end face of the valve body (1) by a fixing assembly. A limiting assembly is provided between the lower ends of the valve body (1) and the valve shaft (3). The outer periphery of the valve plate (2) and the valve body (1) are connected. A sealing assembly is provided between the valve shaft (3) and the bottom of the valve body (1). A flat bearing (23) is provided at the bottom of the valve shaft (3). A bottom flange (26) is provided at the bottom of the valve body (1). The flat bearing (23) and the bottom flange (26) are fixed. A flushing short pipe (18) is provided between the flange end of the valve body (1) and the field pipeline. A closed welding chamber (29) is provided inside the flushing short pipe (18). The welding chamber is provided with a row of oblique through holes (30). The axis of the oblique through holes (30) is aligned with the sealing surface of the valve body (1).

2. The external butterfly valve sealing surface flushing device according to claim 1, characterized in that: The valve plate (2) and the valve shaft (3) are connected in the valve cavity of the valve body (1) by a flat key (16).

3. The external butterfly valve sealing surface flushing device according to claim 1, characterized in that: The valve plate (2) and valve shaft (3) are fixed by hexagonal head positioning bolts (10).

4. The external butterfly valve sealing surface flushing device according to claim 1, characterized in that: The bottom of the bushing (6) is provided with a graphite packing (9), and the graphite packing (9) and the bushing (6) are arranged from bottom to top between the upper end of the valve body (1) and the valve shaft (3).

5. The external butterfly valve sealing surface flushing device according to claim 1, characterized in that: The packing assembly includes a packing pad (7), graphite packing (8), packing gland (14), and packing pressure plate (15) arranged sequentially from bottom to top. The fixing assembly includes a fully threaded stud (11), a hexagonal nut (12), and a butterfly spring (13). The butterfly spring (13) is provided on the packing pressure plate (15). The packing pressure plate (15) and the valve body (1) are fastened to the end face of the valve body (1) by the fully threaded stud (11) and the hexagonal nut (12).

6. The external butterfly valve sealing surface flushing device according to claim 1, characterized in that: The limiting assembly includes a plane bearing (20), a pressure ring (21), and a split ring (22), which are arranged from top to bottom between the lower end of the valve body (1) and the valve shaft (3).

7. The external butterfly valve sealing surface flushing device according to claim 1, characterized in that: The sealing assembly includes a first metal spiral wound gasket (17), a sealing ring (5) and a pressure ring (4). The sealing ring (5) is provided on the outer periphery of the valve plate (2). The sealing ring (5) is pressed onto the valve plate (2) by the pressure ring (4) and fastened by an internal hex screw (28). The first metal spiral wound gasket (17) is provided between the sealing ring (5) and the valve plate (2).

8. The external butterfly valve sealing surface flushing device according to claim 1, characterized in that: An adjusting pad (24) is provided at the bottom of the planar bearing (23). The adjusting pad (24) is located between the bottom of the planar bearing (23) and the bottom flange (26). A second metal spiral wound pad (25) is provided between the bottom flange (26) and the bottom of the valve body (1). The planar bearing (23) and the bottom flange (26) are fastened to the bottom of the valve body (1) by hexagonal head bolts (27).

9. The external butterfly valve sealing surface flushing device according to claim 1, characterized in that: The external interface of the flushing short pipe (18) is equipped with a shut-off check valve (19); a flange metal spiral wound gasket is provided between the flushing short pipe (18), the flange end of the valve body (1), and the field pipeline. The flushing short pipe (18) and the flange metal spiral wound gasket are installed between the flange end of the valve body (1) and the field pipeline through pipe flange studs and nuts.

10. The external butterfly valve sealing surface flushing device according to claim 7, characterized in that: The oblique through hole (30) of the welding chamber of the external flushing short circuit (18) is located near the valve body (1) and the sealing ring (5).

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