Oil-sealed valve
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Help: What is the difference between an automatic leveling oil seal valve and a differential pressure oil seal valve? Please provide as much detail as possible. reward_7ree
Product overview of automatically leveling oil-sealed gate valves: The structural principle of these automatically leveling oil-sealed gate valves is based on the existing wedge-type elastic gate valve design. That is, at the position of the valve seat in the middle chamber of the conventional wedge-type gate valve body, an automatic oil-pressure sealing and lubrication mechanism is installed. This mechanism consists of a cylinder filled with sealing grease, a piston that can move along the inner surface of the cylinder, and the valve seat. When the valve is closed, the middle chamber of the valve body is filled with medium pressure. Behind the valve, that is, at its downstream end, the flow of medium is interrupted, creating a pressure difference with the middle chamber. This pressure difference drives the piston downward, thereby compressing the sealing grease inside the cylinder. This compressed grease then enters through the valve seat channels and forms a sealing oil film on the valve seat surface, thus achieving sealing. At the front and rear parts outside the valve body, there is a seal grease compensation pressing mechanism in each location. When seal grease needs to be replenished due to leakage in the valve, simply rotating the gland allows the seal grease to enter through the oil holes in the valve body and reach the sealing surface of the valve seat, thereby re-establishing the seal. Materials for the main components of automatic leveling oil-sealed gate valves: Names of components in gas valves, materials used for gas valves. Valve body and valve cover: cast steel and sulfur-resistant materials. Gate and sealing seat: chromium stainless steel (or welded cemented carbide). Valve stem: chromium stainless steel or chromium-silicon-molybdenum steel as well as 316 material. Valve stem nut: ductile iron or aluminum bronze. Packing: polytetrafluoroethylene or PTFE. Handwheel: ductile iron. Technical parameters of automatic leveling oil-sealed gate valves: Test pressure of gas valves in MPA: 2.5, 4.0, 6.4 (sealing test); bgf/cm2 values: 28, 44, 71. Test pressure in MPA: 3.8, 6.4, 9.6 (strength test); bgf/cm2 values: 38, 96, 96. Applicable media: oils, gas-water (industrial water). Operating temperature: ≤450°C. Instructions for ordering automatic leveling oil-sealed gate valves: 1. Product model and name; 2. Nominal diameter (DN); 3. Rated flow coefficient KV; 4. Nominal pressure and pressure difference; 5. Materials for valve body and internal components; 6. Flow characteristics; 7. Applicable temperature range; 8. Power supply voltage and control signal; 9. Whether accessories are included; 10. Composition of the medium used. The differential pressure oil-sealed flat gate valve features a new type of floating seal structure and is suitable for use in pipelines carrying oils, natural gas, etc., under pressures not exceeding 15.0 MPa and at temperatures ranging from -29 to 121°C. It serves as a device for controlling the opening, closing, and regulation of the medium flow. This product boasts a novel design, appropriate material selection, rigorous testing, and easy operation. It also exhibits strong resistance to corrosion, wear, and erosion, making it an ideal new type of equipment for the petroleum industry. II. Structural Features and Working Principle of the Differential Pressure Oil-Sealed Flat-Plate Gate Valve 1. It features a floating valve seat, enabling two-way operation; it provides reliable sealing and smooth operation. 2. All gate plates are provided with guide strips for precise guidance, and their sealing surfaces are spray-welded with cemented carbide to resist erosion. 3. The valve body has high load-bearing capacity; the flow path is straight-through. When fully open, it communicates with the gate plate’s flow guide holes, similar to a straight pipe, resulting in very low flow resistance. The valve stem uses a composite packing with multiple seals, ensuring reliable sealing and low friction. 4. To close the valve, turn the handwheel clockwise; the gate moves downward to its bottom position. Due to the pressure of the medium, the sealing seat at the inlet side is pushed toward the gate, creating a high sealing pressure that thus forms the first layer of seal. At the same time, the gate plate is pressed against the sealing seat at the outlet end, creating a double seal. 5. Thanks to the dual sealing, it is possible to replace wear parts without affecting the operation of the pipeline. This is an important feature that gives our factory’s products an advantage over similar products at home and abroad. 6. To open the gate plate, rotate the handwheel counterclockwise; the gate plate moves upward, causing the flow guide hole and the channel hole to become connected. As the gate plate rises, the through-hole gradually enlarges; when it reaches its extreme position, the guide hole coincides with the channel hole, at which point it is fully open. III. Performance Specifications for Differential Pressure Oil-Sealed Flat Gate Valves
Nominal Pressure: 1.0, 1.6, 2.5, 4.0, 6.4, 10.0
Nominal Diameter: DN40–DN700
Operating Pressure (MPa): ≤1.0, ≤1.6, ≤2.5, ≤4.0, ≤6.4, ≤10.0
Strength Test (MPa): 2.0, 2.4, 3.75, 6.0, 9.6, 15.0
Sealing Test (MPa): 1.1, 1.76, 2.75, 4.4, 7.1, 11.0
Working Medium: Water, oils, natural gas, etc.
Operating Temperature: –29–121°C
IV. Usage, Maintenance, and Precautions for Differential Pressure Oil-Sealed Flat Gate Valves
1. The valves undergo strength and sealing tests prior to leaving the factory; all connections must be maintained in their original state during use. 2. The operation handwheel of these valves is marked with indicators indicating the direction of opening and closing; the top part of the rod-type design is equipped with a scale showing the opening height, which serves as a guide for adjustment. 3. When welding this valve to the pipeline, the valve should be opened, and the neck area should be protected with a damp material to minimize heat transfer and prevent damage to the sealing packing. 4. It is strictly prohibited to use a force applicator when closing the valve; once the gate is closed to the top, the handwheel should be turned 1/2 turn to keep the gate in a floating position. 5. During operation, a fixed amount of lubricating grease should be regularly injected into the grease filling port of the valve cap. 6. During use, if the valve leaks due to wear-prone components, they should be replaced promptly. 7. During maintenance of the valve, its internal cavity should be cleaned thoroughly, and lubricant should be applied to all moving parts during assembly. 8. During storage and when the valve is not in use, the gate should be kept in the closed position. For long-term storage, it should be placed in a well-ventilated and dry area, with regular inspection and maintenance. 1. The valve seat features a floating valve seat structure with O-ring sealing and pre-tensioning, ensuring two-way sealing at both the inlet and outlet of the flat gate valve ； Moreover, the opening and closing torque of this structure is only 1/2 that of ordinary valves, allowing for easy operation of the valve. 2. When fully open, the flow path is smooth and linear, resulting in an extremely low flow resistance with no pressure loss; this enables the use of wool balls to clean the pipelines. 3. It features a packing structure with self-sealing capabilities, eliminating the need for frequent adjustments. Operation is very simple, and the sealing performance is reliable. An auxiliary sealing grease injection mechanism is provided at the packing box, ensuring absolutely reliable sealing and true zero leakage ； It eliminates the problem of leakage that often occurs at the packing of general-purpose valves. 4. When the flat gate valve is closed, it automatically releases the high pressure inside the chamber, ensuring safe use. 5. It features a fully enclosed design with excellent protective properties, enabling operation in all weather conditions. 6. The sealing structure of the valve seat should be elastic and have a presetting force, with both the upstream and downstream sealing surfaces providing sealing functionality. There is always a face-to-face seal between the valve seat and the seal. 7. The valve seat has a self-cleaning function, and it is not directly exposed to airflow during the opening or closing of the valve. The valve seat should be made of a lubricated, wear-resistant material. 8. Failures of the valve actuator do not affect other parts of the valve, and maintenance and replacement can be carried out without removing the valve. 9. Yoke sleeve – The aluminum-bronze yoke sleeve is equipped with needle thrust bearings to minimize operating torque. 10. Valve stem – thread length up to the bracket ； Pins and spot welding ； It has stability. 11. Pressure sealing – Simple in design, it features segmented clamps and silver-plated low-carbon steel washers, which facilitate disassembly and ensure optimal sealing of the valve cap. 12. Seat ring – The welded seat ring is perpendicular to the flow channel, facilitating maintenance. 13. Actuators – These valves can be equipped with electric, hydraulic, or pneumatic actuators. For sizes below DN300, standard hand cranks are used; for sizes above DN350, helical gear operating mechanisms are employed. 14. Yoke – The fully assembled yoke passes seismic tests, and is easy to maintain and install actuators. 15. Cover – two-piece, self-adjusting cover to prevent it from being ejected. 16. Overall rear seat – rigid surface, longest service life. 17. Valve disc – The spring-loaded valve disc can adjust itself, reducing the torque requirement of the actuator. 18. Integral stop – An integrally cast bracket stop device that positions the assembled bracket valve disc, thereby providing a more stable and reliable valve seat. 19. The valve body comes in two structures: cast and welded. 20. The valve seat features a floating seat structure with O-ring sealing and pre-tensioning, ensuring two-way sealing at both the inlet and outlet of the valve ； Moreover, the opening and closing torque of this structure is only 1/2 that of ordinary valves, allowing for easy operation of the valve. 21. Valves with metal-to-metal sealing, featuring a grease injection mechanism on the outside of the valve body; grease is introduced to the valve’s sealing surfaces through a grease injector and the valve seat, thereby achieving zero leakage. 22. The valve seat features PTFE inlaid on the sealing surface, providing dual sealing – PTFE sealing between metal and metal – while also serving to remove debris from the gate. 23. The gate and valve seat are treated using special processes, with cemented carbide sprayed and welded on them, as well as wear-resistant PTFE, to achieve dual sealing. Oil can also be injected for auxiliary sealing, providing dual protection; thus the sealing is more reliable and the service life is longer. 24. The gate of the valve with guide holes remains in contact with the sealing surface whether it is fully open or fully closed, thereby protecting the sealing surface from direct exposure to the medium and extending its service life. 25. When the valve is fully open, the flow path is smooth and straight; the flow resistance coefficient is extremely low, with no pressure loss, allowing the use of wool balls to clean the pipelines. 26. This valve features a packing structure with self-sealing capability, eliminating the need for frequent adjustments. It is very easy to open and close, and offers reliable sealing. An auxiliary sealant injection mechanism is provided at the packing box, ensuring absolutely reliable sealing and true zero leakage ； It addresses the problem of leakage that most commonly occurs at the packing of general-purpose valves. 27. The valve can automatically release the high pressure in its interior when it is closed, ensuring safe use. 28. Fully enclosed structure with excellent protection performance, capable of meeting all-weather requirements. 29. The valve is equipped with an indicator rod or observation window to indicate its open or closed state.
Nominal Pressure: 1.0, 1.6, 2.5, 4.0, 6.4, 10.0
Nominal Diameter: DN40–DN700
Operating Pressure (MPa): ≤1.0, ≤1.6, ≤2.5, ≤4.0, ≤6.4, ≤10.0
Strength Test (MPa): 2.0, 2.4, 3.75, 6.0, 9.6, 15.0
Sealing Test (MPa): 1.1, 1.76, 2.75, 4.4, 7.1, 11.0
Working Medium: Water, oils, natural gas, etc.
Operating Temperature: –29–121°C
IV. Usage, Maintenance, and Precautions for Differential Pressure Oil-Sealed Flat Gate Valves
1. The valves undergo strength and sealing tests prior to leaving the factory; all connections must be maintained in their original state during use. 2. The operation handwheel of these valves is marked with indicators indicating the direction of opening and closing; the top part of the rod-type design is equipped with a scale showing the opening height, which serves as a guide for adjustment. 3. When welding this valve to the pipeline, the valve should be opened, and the neck area should be protected with a damp material to minimize heat transfer and prevent damage to the sealing packing. 4. It is strictly prohibited to use a force applicator when closing the valve; once the gate is closed to the top, the handwheel should be turned 1/2 turn to keep the gate in a floating position. 5. During operation, a fixed amount of lubricating grease should be regularly injected into the grease filling port of the valve cap. 6. During use, if the valve leaks due to wear-prone components, they should be replaced promptly. 7. During maintenance of the valve, its internal cavity should be cleaned thoroughly, and lubricant should be applied to all moving parts during assembly. 8. During storage and when the valve is not in use, the gate should be kept in the closed position. For long-term storage, it should be placed in a well-ventilated and dry area, with regular inspection and maintenance. 1. The valve seat features a floating valve seat structure with O-ring sealing and pre-tensioning, ensuring two-way sealing at both the inlet and outlet of the flat gate valve ； Moreover, the opening and closing torque of this structure is only 1/2 that of ordinary valves, allowing for easy operation of the valve. 2. When fully open, the flow path is smooth and linear, resulting in an extremely low flow resistance with no pressure loss; this enables the use of wool balls to clean the pipelines. 3. It features a packing structure with self-sealing capabilities, eliminating the need for frequent adjustments. Operation is very simple, and the sealing performance is reliable. An auxiliary sealing grease injection mechanism is provided at the packing box, ensuring absolutely reliable sealing and true zero leakage ； It eliminates the problem of leakage that often occurs at the packing of general-purpose valves. 4. When the flat gate valve is closed, it automatically releases the high pressure inside the chamber, ensuring safe use. 5. It features a fully enclosed design with excellent protective properties, enabling operation in all weather conditions. 6. The sealing structure of the valve seat should be elastic and have a presetting force, with both the upstream and downstream sealing surfaces providing sealing functionality. There is always a face-to-face seal between the valve seat and the seal. 7. The valve seat has a self-cleaning function, and it is not directly exposed to airflow during the opening or closing of the valve. The valve seat should be made of a lubricated, wear-resistant material. 8. Failures of the valve actuator do not affect other parts of the valve, and maintenance and replacement can be carried out without removing the valve. 9. Yoke sleeve – The aluminum-bronze yoke sleeve is equipped with needle thrust bearings to minimize operating torque. 10. Valve stem – thread length up to the bracket ； Pins and spot welding ； It has stability. 11. Pressure sealing – Simple in design, it features segmented clamps and silver-plated low-carbon steel washers, which facilitate disassembly and ensure optimal sealing of the valve cap. 12. Seat ring – The welded seat ring is perpendicular to the flow channel, facilitating maintenance. 13. Actuators – These valves can be equipped with electric, hydraulic, or pneumatic actuators. For sizes below DN300, standard hand cranks are used; for sizes above DN350, helical gear operating mechanisms are employed. 14. Yoke – The fully assembled yoke passes seismic tests, and is easy to maintain and install actuators. 15. Cover – two-piece, self-adjusting cover to prevent it from being ejected. 16. Overall rear seat – rigid surface, longest service life. 17. Valve disc – The spring-loaded valve disc can adjust itself, reducing the torque requirement of the actuator. 18. Integral stop – An integrally cast bracket stop device that positions the assembled bracket valve disc, thereby providing a more stable and reliable valve seat. 19. The valve body comes in two structures: cast and welded. 20. The valve seat features a floating seat structure with O-ring sealing and pre-tensioning, ensuring two-way sealing at both the inlet and outlet of the valve ； Moreover, the opening and closing torque of this structure is only 1/2 that of ordinary valves, allowing for easy operation of the valve. 21. Valves with metal-to-metal sealing, featuring a grease injection mechanism on the outside of the valve body; grease is introduced to the valve’s sealing surfaces through a grease injector and the valve seat, thereby achieving zero leakage. 22. The valve seat features PTFE inlaid on the sealing surface, providing dual sealing – PTFE sealing between metal and metal – while also serving to remove debris from the gate. 23. The gate and valve seat are treated using special processes, with cemented carbide sprayed and welded on them, as well as wear-resistant PTFE, to achieve dual sealing. Oil can also be injected for auxiliary sealing, providing dual protection; thus the sealing is more reliable and the service life is longer. 24. The gate of the valve with guide holes remains in contact with the sealing surface whether it is fully open or fully closed, thereby protecting the sealing surface from direct exposure to the medium and extending its service life. 25. When the valve is fully open, the flow path is smooth and straight; the flow resistance coefficient is extremely low, with no pressure loss, allowing the use of wool balls to clean the pipelines. 26. This valve features a packing structure with self-sealing capability, eliminating the need for frequent adjustments. It is very easy to open and close, and offers reliable sealing. An auxiliary sealant injection mechanism is provided at the packing box, ensuring absolutely reliable sealing and true zero leakage ； It addresses the problem of leakage that most commonly occurs at the packing of general-purpose valves. 27. The valve can automatically release the high pressure in its interior when it is closed, ensuring safe use. 28. Fully enclosed structure with excellent protection performance, capable of meeting all-weather requirements. 29. The valve is equipped with an indicator rod or observation window to indicate its open or closed state.
I remember there being only one differential pressure oil-sealed gate valve. Almost no one uses this anymore. All have been replaced with flat gate valves·~
The structural principle of the automatically leveling oil-sealed gate valve is developed on the basis of the existing wedge-type elastic gate valve structure. That is, at the position of the valve seat in the middle cavity of the existing wedge-type gate valve body, an automatic oil-pressure sealing and lubrication mechanism is installed. This mechanism consists of an oil cylinder filled with sealing grease, a piston that can move along the inner surface of the oil cylinder, and the valve seat. When the valve is closed, the middle cavity of the valve body is filled with medium pressure. Behind the valve, that is, at its downstream end, the flow of medium is interrupted, creating a pressure difference with the middle cavity. Under this pressure difference, the piston is pushed downward, compressing the sealing grease inside the oil cylinder. This grease then enters through the valve seat channels and forms a sealing oil film on the valve seat surface, thereby achieving sealing. At the front and rear parts outside the valve body, there is a seal grease compensation pressing mechanism in each location. When seal grease needs to be replenished due to leakage in the valve, simply rotating the gland allows the seal grease to enter through the oil holes in the valve body and reach the sealing surface of the valve seat, thereby re-establishing the seal. Structural features and working principle of the differential pressure oil-sealed flat gate valve: 1. It features a floating valve seat, enabling two-way operation; it provides reliable sealing and flexible operation. 2. All gate plates are provided with guide strips for precise guidance, and their sealing surfaces are spray-welded with cemented carbide to resist erosion. 3. The valve body has high load-bearing capacity; the flow path is straight-through. When fully open, it communicates with the gate plate’s flow guide holes, similar to a straight pipe, resulting in very low flow resistance. The valve stem uses a composite packing with multiple seals, ensuring reliable sealing and low friction. 4. To close the valve, turn the handwheel clockwise; the gate moves downward to its bottom position. Due to the pressure of the medium, the sealing seat at the inlet side is pushed toward the gate, creating a high sealing pressure that thus forms the first layer of seal. At the same time, the gate plate is pressed against the sealing seat at the outlet end, creating a double seal. 5. Thanks to the dual sealing, it is possible to replace wear parts without affecting the operation of the pipeline. This is an important feature that gives our factory’s products an advantage over similar products at home and abroad. 6. To open the gate plate, rotate the handwheel counterclockwise; the gate plate moves upward, causing the flow guide hole and the channel hole to become connected. As the gate plate rises, the through-hole gradually enlarges; when it reaches its extreme position, the guide hole coincides with the channel hole, at which point it is fully open.
Are it the price and control factors?