Coking four-way ball valve

Abstract

This application relates to a coking four-way ball valve, belonging to the field of valve technology. It includes a first valve body, a valve sleeve, and an elastic sealing assembly. The bellows, fixed ring, fixed valve seat, and guide tube in the elastic sealing assembly together form a sealed annular pressure chamber. At least one gas flow channel is machined on the valve sleeve, with its first port normally connected to the pressure chamber and its second port used to connect to a gas supply device to introduce protective gas into the pressure chamber to maintain pressure balance. Furthermore, a two-stage passive protection system consisting of a safety valve assembly and a rupture disc assembly can be set. Layered redundant protection of the bellows back pressure is achieved through stepped pressure settings, and post-event traceability of leakage events can be achieved through an irreversible color-changing thermal patch. This application requires no external energy source and can effectively protect the bellows even under extreme operating conditions, improving the safety and reliability of the coking four-way ball valve.

Description

Technical Field

[0001] This application relates to the field of valve technology, and in particular to a coking four-way ball valve. Background Technology

[0002] In the delayed coking unit of an oil refinery, high-temperature oil is heated in a heater and then alternately switched to multiple reactors via a four-way valve. The four-way valve, as a switching element, needs to operate reliably for extended periods in a high-temperature, coke-containing medium at around 500°C. Traditional four-way valves use a helical spring as an elastic compensation element after the valve seat. However, the spring is directly exposed to the coke-containing environment, and long-term use can easily lead to coking, sticking, elastic decay, or even breakage. This results in the valve seat failing to effectively conform to the spherical surface, causing internal leakage and switching failures.

[0003] To address the problem of spring coking failure, existing technologies have developed bellows four-way ball valves that use metal bellows instead of springs. These valves rely on the axial elasticity of the bellows to push the valve seat against the spherical surface, while simultaneously using a guide tube to isolate the coke-containing medium from the chamber where the bellows is located.

[0004] However, because the bellows is a thin-walled metal structure, its wall thickness is usually much smaller than its diameter, making it highly sensitive to pressure differences between the inside and outside. In actual operation, the sealed chamber formed between the bellows and the guide tube contains gas. When valve switching operations or temperature fluctuations cause the gas in the chamber to expand due to heat, or when a small amount of medium from inside the valve enters the chamber through the gap in the guide tube, the pressure in the sealed chamber may rise abnormally and exceed the allowable external pressure of the bellows, causing the bellows to buckle and become unstable. Once the bellows loses its shape stability, its elastic compensation ability will decrease significantly, and in severe cases, irreversible structural damage may occur, causing the entire sealing assembly to fail. Summary of the Invention

[0005] The purpose of this application is to provide a coking four-way ball valve to overcome the above-mentioned technical problems.

[0006] The coking four-way ball valve provided in this application adopts the following technical solution: A coking four-way ball valve includes a first valve body, a valve core disposed within the first valve body, a rotary drive mechanism for driving the valve core to rotate, and an elastic sealing assembly. The first valve body is provided with a valve sleeve, and the elastic sealing assembly is installed inside the valve sleeve to form a floating seal with the spherical surface of the valve core. The elastic sealing assembly includes a fixing ring, a bellows, and a fixed valve seat. The fixing ring is fixed to the inner wall of the valve sleeve. One end of the bellows is welded to the fixing ring, and the other end is welded to the fixed valve seat. The front end face of the fixed valve seat is a spherical sealing surface that mates with the spherical surface of the valve core. A guide tube is inserted inside the valve sleeve, and the outer wall of the guide tube is clearance-fitted with the inner hole of the fixed valve seat. The bellows, the fixing ring, the fixed valve seat, and the outer wall of the guide tube together form a closed annular pressure chamber. At least one gas flow channel is machined on the valve sleeve. The gas flow channel has a first port and a second port. The first port is opened on the inner wall of the valve sleeve and is normally open to the pressure chamber. The second port is used to connect to an external gas supply device to introduce protective gas into the pressure chamber during normal valve operation.

[0007] By employing the above technical solution, an inert protective gas at a predetermined pressure is introduced into the sealed pressure chamber, maintaining pressure balance on both the inner and outer sides of the bellows and preventing buckling instability due to excessive pressure difference. The positive pressure environment within the pressure chamber prevents the intrusion of external media containing coke powder, extending the service life of the bellows. This solution addresses the back pressure protection problem of the bellows, a thin-walled elastic element, by positioning the gas flow channel within the pressure chamber for pressure regulation.

[0008] Optionally, there are two gas channels, namely a first gas channel and a second gas channel. Both the first gas channel and the second gas channel have a first port and a second port. The first port is opened on the inner wall of the valve sleeve and is always in communication with the pressure chamber.

[0009] By adopting the above technical solution, the two independent gas channels allow the intake and possible venting functions of the pressure chamber to be distributed to different channels, avoiding the possible conflicts that may occur when a single channel undertakes both the intake and venting functions at the same time; at the same time, the two channels can work together to supply gas under normal working conditions, improve the supply efficiency, and shorten the pressure build-up time in the pressure chamber.

[0010] Optionally, the second port of the first gas flow channel is connected to a first medium pipe, and the end of the first medium pipe away from the valve sleeve is connected to a one-way valve. The outlet of the one-way valve is in fluid communication with the first medium pipe, and the inlet of the one-way valve is used to connect to an external gas supply device.

[0011] By adopting the above technical solution, the one-way valve only allows the protective gas to flow from the gas replenishment device to the pressure chamber, preventing the medium from leaking back and ensuring that the protective gas in the pressure chamber will not flow back under the condition of pressure fluctuation of the gas replenishment device; the first medium pipe, as a fixed gas replenishment channel, can always maintain a reliable connection with the gas replenishment device, providing continuous and stable positive pressure protection for the pressure chamber.

[0012] Optionally, the second port of the second gas flow channel is connected to a second medium pipe. The second medium pipe has the function of selectively connecting one of the gas replenishment device and the protection system, so that when connected to the gas replenishment device, it can work with the first gas flow channel to replenish gas to the pressure chamber, or when connected to the protection system, it can work with the second gas flow channel to form a release initiation channel for leading the overpressure medium in the pressure chamber outward.

[0013] By adopting the above technical solution, the second medium pipe, as a standard interface with dual functions, eliminates the need to open a separate vent hole on the valve sleeve, maintains the integrity of the valve pressure boundary, and provides users with flexible functional configuration options.

[0014] Optionally, a protection system is connected to the end of the second medium pipe away from the valve sleeve. The protection system includes a pressure-tapping assembly, a protection block, a first-stage pressure relief assembly, and a second-stage pressure relief assembly. The pressure-tapping assembly is used to fluidly connect the second medium pipe to the protection block. A main pressure relief chamber is formed inside the protection block, and the pressure-tapping assembly is connected to the main pressure relief chamber through an inlet flow channel on the protection block. The first-stage pressure relief assembly and the second-stage pressure relief assembly are respectively connected to the main pressure relief chamber.

[0015] By adopting the above technical solution, the functions of drawing out, distributing and releasing overpressure medium are integrated into a protection block that is independent of the first valve body. The modular design facilitates installation, maintenance and replacement. The pressure-drawing assembly reliably transmits the pressure signal from the pressure chamber to the protection block. The main pressure relief chamber serves as the common interface between the first and second stage pressure relief assemblies, allowing multiple pressure relief elements to be connected in parallel without interference, thus providing a structural basis for graded protection.

[0016] Optionally, the first-stage pressure relief assembly is a safety valve assembly, which includes a second valve body, a valve disc, a safety valve seat, a loading spring, and an adjusting knob. The second valve body is mounted on the protective block, the safety valve seat is fixed inside the second valve body, the valve disc is slidably disposed above the safety valve seat and abuts against the lower end of the loading spring, and the upper end of the loading spring is pressed by the adjusting knob. The opening pressure of the safety valve assembly is set by rotating the adjusting knob to change the preload of the loading spring.

[0017] By adopting the above technical solution, an automatic reset first overpressure protection is provided: when the pressure in the pressure chamber abnormally rises to exceed the safety valve's set opening pressure, the valve disc automatically opens to release pressure; after the pressure returns, the valve disc reseats under the action of the spring force to restore the seal, without manual intervention. The adjusting knob allows for precise calibration of the opening pressure, adapting to bellows with different design parameters.

[0018] Optionally, the second-stage pressure relief assembly is a rupture disc assembly, which includes a lower clamp, a rupture disc, and an upper clamp. The lower clamp is sealed and mounted on the protective block, the rupture disc is placed on the positioning plane of the lower clamp, and the upper clamp presses on the rupture disc and is connected to the lower clamp via fasteners to clamp and seal the rupture disc.

[0019] By adopting the above technical solution, a second-stage ultimate overpressure protection is provided, complementing the function of the safety valve assembly. The rupture disc is a purely mechanical passive component with no moving parts, and is unaffected by coking, jamming, or corrosion of the medium. When the safety valve fails to open normally due to coking, jamming, or other reasons, the rupture disc, as the last line of defense, ruptures and releases pressure under a predetermined pressure, ensuring that the pressure in the pressure chamber never exceeds the safety limit.

[0020] Optionally, the set opening pressure of the safety valve assembly is configured to be greater than the protective gas pressure in the pressure chamber under normal valve operation and less than the allowable external pressure of the bellows; the set burst pressure of the rupture disc is configured to be greater than the set opening pressure of the safety valve assembly and less than the buckling failure pressure of the bellows.

[0021] By adopting the above technical solution and through quantitative pressure gradient settings, a two-level safety redundancy space is established between the normal operating pressure of the protective gas and the failure pressure of the bellows. This layered redundant protection gradient, which follows the order of "protective gas pressure < safety valve opening pressure < rupture disc burst pressure < bellows buckling failure pressure," ensures that the pressure in the pressure chamber is always limited within the safety limit of the bellows throughout the entire abnormal operating condition evolution process, significantly improving the safety of bellows operation.

[0022] Optionally, the protection system also includes a status indicator component, which is disposed on the outer wall of the discharge main pipe connected to the discharge outlet channel of the protection block; the status indicator component includes an irreversible color-changing thermal patch, a transparent sleeve, and a fixing clamp; the thermal patch is attached to the outer circumferential surface of the discharge main pipe and is located downstream of the discharge outlet channel of the protection block, the transparent sleeve is fitted over the pipe section with the thermal patch attached, and the two ends of the transparent sleeve are tightly sealed to the outer wall of the discharge main pipe by the fixing clamp.

[0023] By adopting the above technical solution, a "post-event traceability" function for leakage events is provided, which requires no power supply, no instrument signals, and no real-time personnel on duty. When an overpressure release occurs in a safety valve or rupture disc, the high-temperature medium causes the pipe wall to heat up rapidly, and the heat-sensitive patch undergoes an irreversible color change. Inspection personnel can observe the color change through the transparent sheath, thus determining that the valve has experienced a back pressure release event and arranging maintenance.

[0024] Optionally, the pressure-applying assembly includes an adapter block and a connecting pipe; one end of the adapter block is fixedly connected to the end flange of the second medium pipe by bolts, and the other end is sealed to the connecting pipe; the other end of the connecting pipe is sealed to the inlet flow channel of the protective block.

[0025] By adopting the above technical solutions, the adapter block is connected by flange bolts to ensure connection strength and sealing reliability under high pressure conditions; the connecting pipe, as a flexible connector, can adapt to spatial layout deviations and reduce installation accuracy requirements; the overall pressure-sensing assembly is a detachable structure, which facilitates independent maintenance and replacement of the protection system without the need to modify the valve sleeve and medium pipe.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. By introducing protective gas into the sealed pressure chamber, the pressure balance inside and outside the bellows is maintained, which prevents the bellows from buckling and becoming unstable from the source, while preventing the intrusion of coke-containing media and extending the service life of the bellows.

[0027] 2. By setting up a dual gas flow channel and dual medium pipe structure, the second medium pipe has both gas supply and venting functions, realizing a flexible configuration for coordinated gas supply under normal working conditions and venting under abnormal working conditions. There is no need to open additional holes on the valve sleeve, thus maintaining the integrity of the valve pressure boundary.

[0028] 3. Two-stage redundant protection is achieved by using the safety valve assembly and the rupture disc assembly. A quantified pressure gradient setting (protective gas pressure < safety valve opening pressure < rupture disc burst pressure < bellows buckling failure pressure) is used to achieve layered protection for the bellows pressure chamber, ensuring that the bellows will never be subjected to external pressure exceeding its buckling failure pressure under extreme conditions where the active gas supply system fails.

[0029] 4. By setting up a status indicator component based on an irreversible color-changing thermal patch, and taking the release of a safety valve or rupture disc as a trigger condition, the system can achieve post-event traceability of release events without the need for power supply and instrument signals, filling the gap in fault recording and traceability of purely mechanical protection systems.

[0030] 5. The entire protection system is a purely mechanical structure, requiring no external power supply, instrument fan, or control signal. It can still operate normally under extreme conditions such as power outages and gas outages, meeting the actual needs of long unattended operation cycles for delayed coking units. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of this application; Figure 2 This is an exploded structural diagram of Embodiment 1 of this application; Figure 3 This is a cross-sectional structural diagram of Embodiment 1 of this application, mainly showing the pressure chamber; Figure 4 This is a schematic diagram of the overall structure of Embodiment 2 of this application; Figure 5 This is a schematic diagram of embodiment 2 of this application, mainly illustrating the protection system; Figure 6 This is a structural schematic diagram of Embodiment 2 of this application, mainly illustrating the status indicator component; Figure 7 This is a cross-sectional structural diagram of Embodiment 2 of this application, mainly showing the first-stage pressure relief component.

[0032] Explanation of reference numerals in the attached drawings: 1. First valve body; 2. Valve core; 3. Rotary drive mechanism; 4. Air injection pipe; 5. Valve sleeve; 6. Sealing ring; 7. Flow guide tube; 8. Fixing ring; 9. Bellows; 10. Fixed valve seat; 11. Pressure chamber; 12. First medium pipe; 13. Second medium pipe; 14. Check valve; 15. Pressure tapping assembly; 151. Adapter block; 152. Connecting pipe; 16. Protective block; 161. Main pressure relief chamber; 17. First 171. Second stage pressure relief assembly; 172. Valve disc; 173. Safety valve seat; 174. Loading spring; 175. Adjusting knob; 176. Anti-loosening cap; 18. Second stage pressure relief assembly; 181. Lower clamp; 182. Rupture disc; 183. Upper clamp; 184. Relief connection; 19. Status indicator assembly; 191. Thermal patch; 192. Transparent sleeve; 193. Fixing clamp; 20. Relief main pipe. Detailed Implementation

[0033] The following is in conjunction with the appendix Figure 1 -Appendix Figure 7 This application will be described in further detail below. Example

[0034] A coking four-way ball valve, reference Figure 1 , Figure 2 The system includes a first valve body 1, a valve core 2 disposed within the first valve body 1, a rotary drive mechanism 3 for driving the valve core 2 to rotate, and an elastic sealing assembly. The elastic sealing assembly is installed within the first valve body 1 and is used to form a floating seal with the spherical surface of the valve core 2.

[0035] refer to Figure 1 , Figure 2The first valve body 1 has one inlet, three outlets, and one operating port. The inlet and operating port are symmetrically located at both ends of the first valve body 1, and the three outlets are equidistantly arranged on the sides of the first valve body 1. Mounting flanges are integrally formed at the inlet, outlet, and operating port of the first valve body 1. The mounting flange at the inlet of the first valve body 1 is sealed to the external liquid outflow pipe; the mounting flange at the operating port of the first valve body 1 is bolted to a valve cover, which is sealed to the valve cover and serves to support the rotary drive mechanism 3; the mounting flange at each outlet of the first valve body 1 is bolted to a valve sleeve 5, which is sealed to the external liquid inflow pipe.

[0036] An operating hole is provided in the middle of the valve cover. An operating rod integrally formed on the valve core 2 passes through the operating hole and is connected to the rotary drive mechanism 3. A shaft seal assembly is fixed to the valve cover at the operating hole by bolts to prevent leakage of liquid flowing through the first valve body 1. An air injection channel is integrally formed inside the valve cover. The inlet of the air injection channel is located on the side of the valve cover, and its outlet is located on the inner wall of the operating hole and communicates with the operating hole. An air injection pipe 4 is fixed to the side of the valve cover by welding. The outlet of the air injection pipe 4 is in fluid communication with the inlet of the air injection channel. The outlet of the air injection pipe 4 is integrally formed with a flange for connecting to an external air supply device.

[0037] refer to Figure 2 , Figure 3 The valve sleeve 5 is a stepped sleeve-shaped part with a central through hole. Its outer circumference is provided with a mating flange that seals with the outlet of the first valve body 1, and it is bolted to the mounting flange of the first valve body 1. A first sealing ring 6 is installed between the valve sleeve 5 and the first valve body 1 to ensure a tight seal between them. An annular elastic component mounting groove is formed on the inner wall of the valve sleeve 5; this groove is a concave annular groove extending radially outward from the valve sleeve 5. A guide tube 7 passes through the first valve body 1, with one end of the guide tube 7 near the mating flange having an interference fit with the inner wall of the valve sleeve 5, and a second sealing ring 6 is installed between them.

[0038] The resilient sealing assembly includes a retaining ring 8, a bellows 9 welded to the retaining ring 8, and a retaining valve seat 10 welded to the bellows 9.

[0039] The fixing ring 8 is a circular metal part. Its outer circumferential surface and the inner wall surface of the mounting groove near the docking flange are welded together to form an unremovable seal. An annular gap is left between the inner wall of the fixing ring 8 and the outer wall of the guide tube 7.

[0040] The bellows 9 has axial expansion and contraction elasticity and radial pressure bearing capacity. One end of the bellows 9 is welded and fixed to the end face of the fixed ring 8, and the other end is welded and fixed to the annular surface of the fixed valve seat 10.

[0041] The fixed valve seat 10 is a ring-shaped hard alloy part. Its front end face is a spherical sealing surface that matches the spherical surface of the valve core 2, and its rear end face is welded to the bellows 9.

[0042] The guide tube 7 is a thin-walled straight cylinder with a clearance fit between its outer wall and the inner hole of the fixed valve seat 10. It is used to separate the liquid flow channel inside the valve sleeve 5 from the elastic component mounting groove, preventing high-temperature coke-containing media from entering the mounting groove.

[0043] Thus, the bellows 9, the fixing ring 8, the fixing valve seat 10, and the outer wall of the guide tube 7 together form a sealed annular pressure chamber 11. This pressure chamber 11 is isolated from the liquid flow channel inside the valve sleeve 5.

[0044] The valve sleeve 5 is integrally machined with a first gas flow channel and a second gas flow channel. Both the first gas flow channel and the second gas flow channel have a first port and a second port. The first port is opened on the inner wall surface of the valve sleeve 5 and is axially positioned between the fixing ring 8 and the mating flange, so that the first gas flow channel and the second gas flow channel are normally connected to the pressure chamber 11 through the annular gap between the inner wall of the fixing ring 8 and the outer wall of the guide tube 7.

[0045] The second ports of both the first and second gas flow channels are located on the outer wall of the valve sleeve 5. A first medium pipe 12 is welded and fixed to the second port of the first gas flow channel, and a second medium pipe 13 is welded and fixed to the second port of the second gas flow channel. One end of the first medium pipe 12 and the second medium pipe 13 are respectively in fluid communication with the second port of the corresponding gas flow channel.

[0046] The other end of the first medium pipe 12 is integrally formed with a first flange, and a one-way valve 14 is connected through the first flange. The one-way valve 14 is then connected to an external gas supply device. Under normal valve operation, the gas supply device introduces protective gas into the pressure chamber 11 through the one-way valve 14, the first medium pipe 12, and the first gas flow channel.

[0047] The other end of the second medium pipe 13 is integrally formed with a second flange. The second flange is used to connect another one-way valve 14 and a gas supply device when the valve is in normal operation, so as to cooperate with the first gas flow channel to supply gas to the pressure chamber 11; or, the second flange is used to connect a protection system when passive safety protection needs to be constructed, in which case the second medium pipe 13 and the second gas flow channel together constitute a venting initiation channel for leading the overpressure medium in the pressure chamber 11 outward.

[0048] In this embodiment, the second medium pipe 13 is connected to another one-way valve 14 through its second flange, and is connected to an external air supply device through the one-way valve 14.

[0049] The implementation principle of this embodiment 1 is as follows: First, the welding fixing rings 8 and the fixing valve seat 10 at both ends of the bellows 9 are welded to the inner wall of the valve sleeve 5 mounting groove and the fixing valve seat 10, respectively. At the same time, a guide tube 7 is set inside the bellows 9. The outer wall of the guide tube 7 is clearance-fitted with the inner hole of the fixing valve seat 10, completely separating the liquid flow channel inside the valve sleeve 5 from the elastic component mounting groove, preventing the high-temperature coke-containing medium from entering the mounting groove. Thus, the bellows 9, fixing rings 8, fixing valve seat 10, and the outer wall of the guide tube 7 together form a closed annular pressure chamber 11. This pressure chamber 11 is isolated from the liquid flow channel inside the valve sleeve 5, so that the bellows 9 does not directly contact the coke-containing medium.

[0050] Secondly, a first gas flow channel and a second gas flow channel are integrally machined on the valve sleeve 5. The first ports of both are located on the inner wall of the valve sleeve 5, and their axial positions are between the fixing ring 8 and the mating flange. They are normally connected to the pressure chamber 11 through the annular gap between the inner wall of the fixing ring 8 and the outer wall of the guide tube 7. The second ports of the two gas flow channels are respectively welded to the first medium pipe 12 and the second medium pipe 13. Both medium pipes are connected to an external gas supply device through flanges and a one-way valve 14. During normal operation, the gas supply device introduces inert protective gas with a predetermined pressure into the pressure chamber 11 through the one-way valve 14, the two medium pipes, and the two gas flow channels to maintain the pressure balance in the pressure chamber 11 and prevent the bellows 9 from buckling and becoming unstable due to excessive internal and external pressure differences.

[0051] Specifically, the second flange of the second medium pipe 13 is designed with a dual-function interface—in normal operation, it connects to the one-way valve 14 and the gas replenishment device, working in conjunction with the first gas flow channel to replenish gas to the pressure chamber 11; when passive safety protection is required, it can be switched to connect to the protection system, at which point the second medium pipe 13 and the second gas flow channel together constitute the initial channel for releasing the overpressure medium in the pressure chamber 11 outwards. The reason for setting two independent medium pipes instead of a single medium pipe is that if only one gas flow channel and medium pipe are set, that channel must simultaneously undertake the dual functions of gas replenishment and release, and external release cannot be achieved when the gas replenishment one-way valve 14 is not disassembled; setting independent first medium pipe 12 and second medium pipe 13 allows the first medium pipe 12 to always remain connected to the gas replenishment device, while the second medium pipe 13 can be flexibly switched for different purposes as needed.

[0052] Through the above scheme, the bellows 9 is effectively supported by the protective gas in the sealed pressure chamber 11. The pressure in the pressure chamber 11 is maintained within the design range through the dual-medium pipe gas replenishment system, and the bellows 9 will not buckle and become unstable due to excessive internal and external pressure difference. The guide tube 7 isolates the coke-containing medium outside the pressure chamber 11 to prevent the bellows 9 from coking and getting stuck. The dual-medium pipe structure provides a standard interface for the subsequent construction of a passive safety protection system, and the function can be expanded without opening additional holes on the valve sleeve 5. Example

[0053] A coking four-way ball valve, reference Figure 4 The difference between this embodiment and Embodiment 1 is that the second medium pipe 13 is not connected to the gas supply device, but is instead connected to a protection system via its second flange. The protection system provides mechanical graded protection without external power when the back pressure of the resilient sealing assembly abnormally increases.

[0054] refer to Figure 3 , Figure 4 The protection system includes a pressure-inducing assembly 15, a protection block 16, a first-stage pressure relief assembly 17, a second-stage pressure relief assembly 18, and a status indicator assembly 19. Its working path is as follows: the overpressure medium in the pressure chamber 11 sequentially passes through the annular gap between the fixed ring 8 and the guide tube 7, the second gas flow channel, the second medium pipe 13, and the pressure-inducing assembly 15, enters the protection block 16, and is then released by either the first-stage pressure relief assembly 17 or the second-stage pressure relief assembly 18, or sequentially. Finally, the status indicator assembly 19 retains a visual record of the release event.

[0055] refer to Figure 5 The pressure-applying assembly 15 includes an adapter block 151 and a connecting pipe 152. The adapter block 151 has a through-hole for pressure application. One end of the adapter block 151 has a third flange, which is bolted to the second flange of the second medium pipe 13, and a third sealing ring 6 is installed between them. The connecting pipe 152 is a high-pressure, thick-walled metal pipe; one end of it is threadedly sealed to the other end of the adapter block 151, and the other end of the connecting pipe 152 is threadedly sealed to the inlet flow channel of the protective block 16.

[0056] refer to Figure 5 , Figure 6 The protective block 16 is an independently installed high-temperature resistant alloy steel block with interconnected cavities inside. An inlet channel is machined on one side of the protective block 16, and the port of the inlet channel is threaded internally and sealed to the connecting pipe 152. The inlet channel extends inward and merges into the main pressure relief chamber 161 located at the center of the protective block 16. The main pressure relief chamber 161 is a cylindrical cavity with a cross-sectional area larger than that of the inlet channel.

[0057] The top of the protective block 16 is machined with a first pressure relief port, which is a threaded hole and communicates with the main pressure relief chamber 161. The other side of the protective block 16 is machined with a second pressure relief port, which is a flange port and also communicates with the main pressure relief chamber 161. The axes of the first and second pressure relief ports are arranged at a predetermined angle in space, so that they are connected in parallel to the main pressure relief chamber 161 without interfering with each other.

[0058] The bottom of the protective block 16 is machined with a discharge outlet channel, one end of which is connected to the main pressure relief chamber 161, and the other end is machined with a joint thread and connected to the discharge main pipe 20.

[0059] refer to Figure 6 , Figure 7 The first-stage pressure relief assembly 17 is a safety valve assembly, which is threadedly installed into the first pressure relief port of the protective block 16. The safety valve assembly includes a second valve body 171, a valve disc 172, a safety valve seat 173, a loading spring 174, an adjusting knob 175, and an anti-loosening cap 176.

[0060] The second valve body 171 is a cylindrical shell with a central through hole, and its lower end is machined with external threads, which are screwed into the first pressure relief port of the protective block 16 for sealing. The safety valve seat 173 is fixed to the lower end of the inner hole of the second valve body 171. The valve disc 172 is disc-shaped and is slidably mounted above the safety valve seat 173, abutting against the lower end of the loading spring 174. The loading spring 174 is a helical compression spring, and its upper end is pressed by the adjusting knob 175. The adjusting knob 175 engages with the internal thread at the upper end of the second valve body 171. By rotating the adjusting knob 175, the preload of the loading spring 174 can be changed, thereby precisely setting the opening pressure of the safety valve assembly. After adjustment, it is locked with a lock nut, and the anti-loosening cap 176 covers the adjusting knob 175 to prevent accidental operation.

[0061] The safety valve assembly is configured with a set opening pressure that is greater than the protective gas pressure in the pressure chamber 11 under normal valve operation, but less than the allowable external pressure of the bellows 9. When the actual pressure in the pressure chamber 11 exceeds this set opening pressure, the valve disc 172, under the action of the medium pressure, overcomes the spring force of the loading spring 174 and leaves the safety valve seat 173. The overpressure medium is discharged through the internal passage of the second valve body 171, causing the pressure in the pressure chamber 11 to drop below the allowable external pressure of the bellows 9. After the pressure in the pressure chamber 11 drops, the valve disc 172 reseats under the action of the loading spring 174, restoring the seal. Thus, the safety valve assembly provides an automatically reset first overpressure protection.

[0062] The second-stage pressure relief assembly 18 is a rupture disc 182 assembly, which is installed at the second pressure relief port of the protective block 16. The rupture disc 182 assembly includes a lower clamp 181, a rupture disc 182, an upper clamp 183, and a relief connector 184.

[0063] The lower clamp 181 is a ring-shaped metal component, one end of which is sealed and installed inside the second pressure relief port, forming a seal with the protective block 16 through a sealing gasket. The rupture disc 182 is a precision-designed arched metal diaphragm, manufactured according to a preset burst pressure, and placed on the positioning plane of the lower clamp 181. The upper clamp 183 presses on the rupture disc 182 and is fastened to the lower clamp 181 with bolts, uniformly clamping the periphery of the rupture disc 182 to form a metal seal. The relief connector 184 is connected to the outlet end of the upper clamp 183 and is used to guide the burst medium into the subsequent pipeline.

[0064] The set burst pressure of the rupture disc 182 is configured to be greater than the set opening pressure of the safety valve assembly and less than the buckling failure pressure of the bellows 9. When the safety valve assembly fails to open normally due to coking, jamming, or other reasons, and the pressure in the pressure chamber 11 continues to rise to the set burst pressure of the rupture disc 182, the rupture disc 182 ruptures, forming a full-bore relief channel, ensuring that the pressure in the pressure chamber 11 does not exceed the ultimate external pressure that the bellows 9 can withstand. Thus, the rupture disc 182 assembly provides a second-stage ultimate overpressure protection that is functionally complementary to the safety valve assembly.

[0065] With the above pressure settings, the protective gas pressure < safety valve opening pressure < rupture disc 182 burst pressure < bellows 9 buckling failure pressure, thus forming a layered redundant protection ladder for the pressure chamber 11 of bellows 9.

[0066] refer to Figure 6 The status indicator component 19 is disposed on the outer wall of the venting manifold 20 to provide a visual traceability indicator without external power after an overpressure venting event occurs in the first-stage venting component 17 or the second-stage venting component 18. The status indicator component 19 includes an irreversible color-changing thermal patch 191, a transparent sheath 192, and a fixing clamp 193.

[0067] The thermal patch 191 is a flexible sheet material. Its temperature-sensing surface undergoes an irreversible color change when subjected to thermal shock exceeding a predetermined temperature threshold. The adhesive side of the thermal patch 191 is directly attached to the outer circumferential surface of the vent manifold 20, with the attachment position located downstream of the vent outlet channel of the protective block 16.

[0068] The transparent sheath 192 is a high-temperature resistant transparent tubular shell that is fitted over the pipe section to which the thermal patch 191 is attached. The two ends of the transparent sheath 192 are tightly sealed to the outer wall of the drain manifold 20 by fixing clamps 193, protecting the thermal patch 191 from external environmental corrosion and allowing inspection personnel to directly observe the color status of the thermal patch 191 through the transparent sheath 192.

[0069] The operating logic of the status indicator component 19 is as follows: It is based on the premise that the safety valve assembly or rupture disc 182 assembly experiences overpressure relief. When the safety valve assembly or rupture disc 182 assembly releases pressure due to overpressure in the pressure chamber 11, a high-temperature medium flows through the relief manifold 20 for a short period, causing a rapid rise in pipe wall temperature. The thermal patch 191 senses this rapid temperature rise and undergoes irreversible discoloration. Even if the valve subsequently returns to normal operation and the pipe wall temperature drops, the patch color remains unchanged. During routine inspections, operators can observe the color change of the thermal patch 191 through the transparent sheath 192, thus determining that a back pressure relief event has occurred and arranging further inspection and maintenance. Therefore, the status indicator component 19 achieves a "post-event traceability" function for relief events without requiring power supply, instrument signals, or immediate personnel monitoring.

[0070] The implementation principle of this embodiment 2 is as follows: When the valve is working normally, the sealing principle of the elastic sealing assembly is the same as in embodiment 1. The external gas supply device introduces protective gas into the pressure chamber 11 through the first medium pipe 12 and the first gas flow channel. The difference from embodiment 1 is that the second medium pipe 13 is not connected to the gas supply device, but is connected to the protection system through its second flange. When the pressure in the pressure chamber 11 is within the normal range, the safety valve assembly remains closed under the action of the loading spring 174, the rupture disc 182 assembly remains intact, and the thermal patch 191 retains its initial color.

[0071] When the pressure in the pressure chamber 11 rises abnormally due to a malfunction in the protective gas control system, internal leakage of the valve, or other abnormalities, and exceeds the set opening pressure of the safety valve assembly, the valve disc 172 of the safety valve assembly, under the action of the medium pressure, overcomes the spring force of the loading spring 174 and leaves the safety valve seat 173 to open and release pressure. The overpressure medium is discharged sequentially through the annular gap between the fixed ring 8 and the guide tube 7, the second gas flow channel, the second medium pipe 13, the adapter block 151, the connecting pipe 152, the inlet flow channel of the protective block 16, the main pressure relief chamber 161, and the internal channel of the second valve body 171, so that the pressure in the pressure chamber 11 drops back to below the allowable external pressure of the bellows 9. After the pressure drops, the valve disc 172 reseats under the action of the loading spring 174 to restore the seal. This is the first overpressure protection that can be automatically reset.

[0072] If the safety valve assembly fails to open normally due to coking, jamming, or other reasons, and the pressure in the pressure chamber 11 continues to rise to the set burst pressure of the rupture disc 182, the rupture disc 182 will rupture, forming a full-bore relief channel. The overpressure medium will be released along the same path through the rupture disc 182 assembly, ensuring that the pressure in the pressure chamber 11 does not exceed the ultimate external pressure that the bellows 9 can withstand. This is the second-level ultimate overpressure protection, which complements the function of the safety valve assembly. Layered redundant protection for the bellows 9 pressure chamber 11 is achieved through a pre-set pressure gradient relationship (protective gas pressure < safety valve opening pressure < rupture disc 182 burst pressure < bellows 9 buckling failure pressure).

[0073] When any overpressure relief event occurs, the high-temperature medium flows through the relief manifold 20 for a short period, causing a rapid rise in the pipe wall temperature. The thermal patch 191 in the status indicator assembly 19 senses this rapid temperature rise and undergoes an irreversible color change. Even after the valve returns to normal operation and the pipe wall temperature drops, the patch color remains unchanged. Inspectors can observe the color change through the transparent sleeve 192 to determine that a backpressure relief event has occurred.

[0074] The entire protection system requires no external power supply, instrument air, or control signals. It relies on the pressure setting logic and physical actions of purely mechanical components to achieve graded protection and event tracing.

[0075] The entire protection system is a mechanical structure, requiring no external power supply, instrument fan, or control signal. It can still operate normally under extreme conditions such as power outages and gas outages, compensating for the shortcomings of active control systems. The recoverable pressure relief of the safety valve and the non-recoverable ultimate protection of the rupture disc 182 form a redundant double insurance, respectively dealing with extreme conditions caused by intermittent overpressure and coking blockage. The thermal patch 191 provides passive event tracing, filling the gap in accident records under unattended conditions. The three-level protection forms a complete functional closed loop of "preventing pressure relief → preventing damage → post-event tracing" through tiered pressure settings, significantly improving the safety and reliability of the coking four-way ball valve under harsh conditions.

[0076] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. A coking four-way ball valve, comprising a first valve body (1), a valve core (2) disposed within the first valve body (1), a rotary drive mechanism (3) for driving the valve core (2) to rotate, and an elastic sealing assembly, characterized in that: The first valve body (1) is provided with a valve sleeve (5), and the elastic sealing assembly is installed inside the valve sleeve (5) to form a floating seal with the spherical surface of the valve core (2); the elastic sealing assembly includes a fixing ring (8), a bellows (9) and a fixed valve seat (10), the fixing ring (8) is fixed to the inner wall of the valve sleeve (5), one end of the bellows (9) is welded to the fixing ring (8) and the other end is welded to the fixed valve seat (10), and the front end face of the fixed valve seat (10) is a spherical sealing surface that mates with the spherical surface of the valve core (2); The valve sleeve (5) is provided with a guide tube (7), and the outer wall of the guide tube (7) is in clearance fit with the inner hole of the fixed valve seat (10); the bellows (9), the fixed ring (8), the fixed valve seat (10) and the outer wall of the guide tube (7) together form a closed annular pressure chamber (11). At least one gas flow channel is machined on the valve sleeve (5). The gas flow channel has a first port and a second port. The first port is opened on the inner wall surface of the valve sleeve (5) and is normally connected to the pressure chamber (11). The second port is used to connect to an external gas supply device to introduce protective gas into the pressure chamber (11) when the valve is in normal working condition.

2. The coking four-way ball valve according to claim 1, characterized in that: There are two gas channels, namely a first gas channel and a second gas channel. Both the first gas channel and the second gas channel have a first port and a second port. The first port is opened on the inner wall of the valve sleeve (5) and is normally open to the pressure chamber (11).

3. The coking four-way ball valve according to claim 2, characterized in that: The second port of the first gas flow channel is connected to a first medium pipe (12). The end of the first medium pipe (12) away from the valve sleeve (5) is connected to a one-way valve (14). The outlet of the one-way valve (14) is in fluid communication with the first medium pipe (12), and the inlet of the one-way valve (14) is used to connect with an external gas supply device.

4. The coking four-way ball valve according to claim 3, characterized in that: The second port of the second gas flow channel is connected to a second medium pipe (13). The second medium pipe (13) has the function of selectively connecting one of the gas replenishment device and the protection system, so that when the gas replenishment device is connected, it can work with the first gas flow channel to replenish the pressure chamber (11) with gas, or when the protection system is connected, it can work with the second gas flow channel to form a release initiation channel for leading the overpressure medium in the pressure chamber (11) outward.

5. The coking four-way ball valve according to claim 4, characterized in that: The end of the second medium pipe (13) away from the valve sleeve (5) is connected to a protection system, which includes a pressure-tapping assembly (15), a protection block (16), a first-stage pressure relief assembly (17), and a second-stage pressure relief assembly (18). The pressure-tapping assembly (15) is used to fluidly connect the second medium pipe (13) to the protection block (16). A main pressure relief chamber (161) is formed inside the protection block (16), and the pressure-tapping assembly (15) communicates with the main pressure relief chamber (161) through the inlet flow channel on the protection block (16). The first-stage pressure relief assembly (17) and the second-stage pressure relief assembly (18) are respectively connected to the main pressure relief chamber (161).

6. The coking four-way ball valve according to claim 5, characterized in that: The first-stage pressure relief assembly (17) is a safety valve assembly, which includes a second valve body (171), a valve disc (172), a safety valve seat (173), a loading spring (174), and an adjusting knob (175). The second valve body (171) is mounted on the protective block (16), the safety valve seat (173) is fixed inside the second valve body (171), the valve disc (172) is slidably disposed above the safety valve seat (173) and abuts against the lower end of the loading spring (174), the upper end of the loading spring (174) is pressed by the adjusting knob (175), and the preload of the loading spring (174) is changed by rotating the adjusting knob (175) to set the opening pressure of the safety valve assembly.

7. The coking four-way ball valve according to claim 6, characterized in that: The second-stage pressure relief assembly (18) is a rupture disc (182) assembly, which includes a lower clamp (181), a rupture disc (182), and an upper clamp (183). The lower clamp (181) is sealed and installed on the protective block (16). The rupture disc (182) is placed on the positioning plane of the lower clamp (181). The upper clamp (183) presses on the rupture disc (182) and is connected to the lower clamp (181) by fasteners to clamp and seal the rupture disc (182).

8. The coking four-way ball valve according to claim 7, characterized in that: The set opening pressure of the safety valve assembly is configured to be greater than the protective gas pressure in the pressure chamber (11) under normal valve operation and less than the allowable external pressure of the bellows (9); the set burst pressure of the rupture disc (182) is configured to be greater than the set opening pressure of the safety valve assembly and less than the buckling failure pressure of the bellows (9).

9. The coking four-way ball valve according to claim 5, characterized in that: The protection system also includes a status indicator component (19), which is disposed on the outer wall of the discharge main pipe (20) connected to the discharge outlet channel of the protection block (16). The status indicator component (19) includes an irreversible color-changing thermal patch (191), a transparent sleeve (192), and a fixing clamp (193). The thermal patch (191) is pasted on the outer circumferential surface of the discharge main pipe (20) and located downstream of the discharge outlet channel of the protection block (16). The transparent sleeve (192) is fitted over the pipe section to which the thermal patch (191) is pasted. The two ends of the transparent sleeve (192) are tightly sealed to the outer wall of the discharge main pipe (20) by the fixing clamp (193).

10. The coking four-way ball valve according to claim 5, characterized in that: The pressure-applying assembly (15) includes an adapter block (151) and a connecting pipe (152); one end of the adapter block (151) is fixedly connected to the end flange of the second medium pipe (13) by bolts, and the other end is sealed to the connecting pipe (152); the other end of the connecting pipe (152) is sealed to the inlet flow channel of the protective block (16).

Images