I. Overview
The plug valve has a simple structure, a quick switch, a small fluid resistance, and a fast angular stroke operation. In an emergency such as an accident, the pipeline can be quickly connected or disconnected. Compared with gate valves and globe valves, the operation is more flexible and the switch is faster. The plug valve uses a plug body with a through hole as the opening and closing member, and the plug body rotates with the valve stem to realize the opening and closing action. Small, non-filled plug valves are also known as "Cock". The plug body of the plug valve is mostly a cone (also a cylinder), and cooperates with the conical hole surface of the valve body to form a seal pair.
Second, soft seal plug valve <br> soft seal plug valve is often used in harsh environments such as corrosive, highly toxic and high-hazard media, strictly forbidden leakage, and the valve material will not pollute the medium. The valve body can be made of carbon steel, alloy steel and stainless steel according to the working medium.
A. The temperature may be employed working medium and F4, F46, PVDF, PP, PO, PE and other self-lubricating liner material, good lubrication, the entire work process Sealing friction coefficient is small, plug flexible operation, long service life .
B. The window structure of the inlet and outlet end of the valve body and the structure of the double-channel grooved sealing ring. During the rotation of the cock, the sealing ratio between the sealing pairs is gradually changed until it reaches the fully open or fully closed position, resulting in sufficient sealing. Compared with the pressure, the sealing pair reaches zero leakage.
C. The double groove sealing ring can not only make the bushing stable in the valve body, but also absorb the slight deformation caused by the temperature difference, and the strong friction between the bushing and the cock, with automatic cleaning The effect is to improve the service life of the sealing surface.
D. The unique reverse lip seal design on the top of the plunger adopts a combination of a soft sealing material diaphragm and a metal diaphragm and a adjusting gasket to adjust the sealing specific pressure between the sealing surfaces, so that the plug can be rotated flexibly and can be guaranteed. Sealing of the outlet end and the middle flange connection.
E. Suitable for high flushing gas hold. Liquid solid phase medium. Such as PVC, urea, phthalic anhydride, caustic soda production equipment, or external leakage requires high medium, such as HF, phosgene and so on.
F. The medium can flow in both directions, the installation direction is not limited, online maintenance is realized, and the use is more convenient.
G. Unique design to prevent static electricity, safe fireproof and safe to use.
Third, the oil lubrication hard seal plug valve <br> oil lubrication hard seal plug valve can be divided into conventional oil lubrication plug valve and pressure balanced plug valve. Special grease is injected from the top of the plug body between the cone hole of the valve body and the plug body to form an oil film to reduce the valve opening and closing torque, improve the sealing performance and service life. The working pressure can reach 64MPa, the high working temperature of Zui can reach 325 degrees, and the large diameter of Zui can reach 600mm.
1, the conventional oil-lubricated plug valves
A. Conventional hard-sealed plug valve, the plug cone is mounted in a formal dress. In order to reduce friction and the valve plug sealing surface, the valve seal construction generally sealed grease seat. The high-pressure sealing oil injected from the high-pressure oil nozzle forms a high-pressure sealing ring around the cock, that is, there is an oil film between the valve body and the sealing surface of the cock cone, which can be closed and lubricated, and is easy to open and close.
B. In order to further reduce the opening and closing force rejection of the plug valve, the method of reducing the diameter of the plug is usually adopted. Therefore, the plug valve usually adopts a rectangular flow passage. This method increases the fluid resistance of the plug valve while reducing the opening and closing torque of the plug valve.
C. Surfacing the STL alloy material in the sealing part of the taper cone or using surface hardening technology to enhance the wear and corrosion resistance of the sealing surface and long service life
D. The surface of the taper cone is finely ground to the mirror surface, and the sealing surface of the valve body is ground to have a lower opening and closing torque.
2, pressure balanced plug valve In order to reduce the torque of the conventional hard seal plug valve, pressure balanced plug valve is often used. In addition to the characteristics of a conventional oil-lubricated plug valve, the pressure-balanced plug valve has the following features:
A. The cocking cone of the pressure balanced plug valve is mounted in a flip-chip configuration. The upper part of the tap cone has a check valve.
When the valve is closed, due to the difference between the upper and lower cross-sectional areas of the cock cone, the injected high-pressure sealing oil causes the plug body to receive an upward lifting force, so that the sealing surface of the plug body and the valve can be better sealed.
Open valve B. In the moment, the pressure medium conduit of the valve body under equilibrium chamber, high pressure seal oil chamber on the cock by downward thrust, leaving a slight gap occurs between the plug and the valve cone sealing surface, The torque when rotating the plug body will be effectively reduced. It also protects the seal pair.
C. Under high temperature conditions, the thermal expansion of the cock can be absorbed by the lifting and lowering to avoid the seal pair wedge.
Oil-lubricated hard-sealed plug valve, although oil lubrication can properly reduce the opening and closing torque, it may cause contamination of the medium. Therefore, the sealing lubricant is selected for the actual working conditions.
4. Lifting plug valve <br>The lift plug valve has various structural forms. The lift plug valve is divided into soft seal and hard seal according to the material of the seal surface. The basic principle is that when the opening is opened, the cock is raised, and the cock is rotated by 90 degrees until the valve is fully opened to reduce the friction with the sealing surface of the valve body; when the valve is closed, the cock is rotated 90 degrees to the closed position and then the valve body is sealed. The surface contact reaches the seal.
1. Double seal lift plug valve Double seal lift plug valve is soft seal structure. The plug body is a cylindrical plug body composed of three plates, the rubber plates on both sides are inlaid with rubber sealing faces, and the middle is a cylindrical wedge plug.
When the valve is opened, the transmission mechanism raises the cock, and the two sides of the plate are closed, so that the combined plug body and the valve sealing surface are separated, and then the plug body is rotated by 90 degrees to the fully open position of the valve.
When the valve is closed, the transmission mechanism rotates the combined plug body by 90 degrees to the closed position, and then pushes the plug body down. After the two side plates contact the bottom of the valve body, the lower wedge plate does not move down, and the middle wedge plug continues to descend, pushing the two side plates through the inclined surface. The inlet and outlet ends are moved so that the soft sealing surface of the side plate is compressed by the valve body sealing surface to be sealed.
The double-sealed lift plug valve has double blocking and discharging functions, and the valve is provided with a pressure balance device to prevent abnormal pressure rise of the system and reduce the resistance of the valve when opening and closing. Since the metal faces are in contact with each other after the sealing ring is compressed, the valve has a fireproof function. The maintenance of the valve is very convenient. The two side plates can be removed from the valve body by removing the end cover of the bottom of the valve body without removing the valve body from the pipeline. Therefore, it is also widely used in oil, natural gas, metallurgical mining, gas engineering, light industrial textiles, ship docks, food and environmental water treatment industries to regulate and open and close pipeline fluids.
2, hard seal lift plug valve metal hard seal lift plug valve valve seat sealing surface can be sealed, the use of the valve is not limited by the flow direction of the medium. When the metal hard seal lift plug valve is closed, the valve seat sealing surface can be pressurized by the hand wheel and the valve stem. By increasing the seal specific pressure, the plug valve can have better sealing performance. The sealing surface of the valve seat is convex, which is convenient for cleaning the sealing surface, and the sealing surface is not easy to accumulate crystal medium or solid particles. Solid is often used in high temperature applications in chemical plants. There are many types of hard seal lift plug valves, and two are common.
A. Handwheel-operated lift plug valve, working principle: rise, make the cock and valve fully open. When closing, turn the handle to rotate the cock 90 degrees to the closed position, then turn the transmission handwheel to lower the cock to seal.
When the valve is opened and closed again, the cock is separated from the valve seat, so the opening and closing of the valve is very easy, and the sealing surface is not easy to be scratched during the opening or closing process, and the valve has a long service life. However, the handle drive torque is small, so the nominal size of the valve used is usually small. The handwheel lift lift plug valve is compact, small in size and low in fluid resistance.
B. Mechanical cross drive lift plug valve, the working principle is: when the valve is opened, the transmission rotates the thread of the valve stem to raise the plug body. After the cock and the sealing surface of the valve body are disengaged, the cock is driven to rotate 90 degrees until the valve is fully opened. When the transmission is turned off, the cock is rotated 90 degrees to the closed position, the cock is no longer rotated, and the driving force turns the thread to lower the cock, and contacts the sealing surface of the valve body to achieve sealing. The mechanical cross drive mechanism can be connected to cylinders, electric devices, hydraulic systems, etc. for remote control.
The mechanical cross drive lift plug valve solves the limitation of insufficient input torque of the drive device, and makes the valve develop toward large diameter and high pressure.
The diameter of the cock of the mechanical cross drive lift plug valve is the same as the diameter of the pipe, and the fluid resistance is small, which is convenient for pigging. The development of oil and natural gas long-distance pipelines is growing.
Five-way, three-way and four-way plug valves <br>Three-way and four-way plug valves are suitable for use in Shanghai equipment, changing the direction of medium flow or media distribution. According to the requirements of the working conditions, you can choose soft seal bushing or soft seal, hard seal lift plug valve.
Hebei Abiding Co.Ltd, a professional food supplier, was established in 2005 in Shijiazhuang, China. We specialize ourselves in supplying Organic Tomato Paste and organic pastas. Conventional ones are also available to supply. We can make the private labels according to the customers' requirement. Our products have EU, NOP and JAS organic certificates. They are also Kosher certified. We have business relationships with importers and wholesalers from around the world, mainly in Europe and America. Over the years, we have earned highly recognition from clients due to our qualified service and steadily increase our market share year after year.
Products and Services
1. OEM service provided. We can do OEM with your brand(print, graphics on the products).
2. We have different types of Organic Pasta.(One-shop service)
3. International certificates. Guarantee our quality and make sure you can sell them all over the world!
Soybean Pasta,Bio Soybean Pasta,Organic Soybean Noodle,Bio Soybean Noodle
Hebei Abiding Co.Ltd , https://www.hebeiabiding.com