In recent years, With the improvement of industry and the requirements of energy conservation and environmental protection policy, the cut-off butterfly valve has been more and more widely used. In the prior technology, the tri-eccentric butterfly valve belongs to torque sealing, and the valve plate is closed more tightly by the torque of the actuator to achieve the sealing effect. However, in some special occasions (such as high temperature catalytic flue gas, gas, sulfur tail gas and other media, the temperature reaches 800°C), due to the existence of thermal expansion stress, the valve will not be able to open, easy to cause serious consequences such as tri-eccentric butterfly valve stuck, affecting industrial production, causing huge economic losses, and even cause safety accidents.
SNT VALVE is specialized in the research of high temperature flue gas device butterfly valve. For the above problems, SNT VALVE proposed to use four-stem eccentric butterfly valve instead of tri-eccentric butterfly valve and aeration butterfly valve as a solution in the industry for the first time, successfully solved the problem for many years, applied for two national patents: a four-stem eccentric butterfly valve (patent No.: ZL201520326489.1 and catalytic device with four-stem eccentric butterfly valve (patent No.: ZL201921719624.3), and commissioned China Petroleum and Chemical Industry Federation wot conduct product identification with Changzhou University, which was awarded as the domestic leader.
Four-link Eccentric Butterfly Valve Application
The AOC-4000 series four-link eccentric butterfly valve, designed by SNT, is widely used as a special condition regulating and shut-off valve.
The AOC-4000 series four-link eccentric butterfly valve is suitable for high-temperature, large-diameter, high-flow, low-pressure drop, low-leakage, and zero-leakage scenarios. Its excellent planar sealing performance prevents valve jamming at high temperatures. This valve offers quick opening and closing, high adjustment accuracy, and reliable sealing, making it especially suitable for the regulation or shut-off of pipeline media in the production processes of phthalic anhydride and maleic anhydride. It can also be used for controlling other gases and liquids, such as hydrogen, ammonia, air, smoke, and gas in pipeline systems. For media prone to crystallization (e.g., sulfur), a jacketed structure can be used to prevent pipeline blockage caused by cooling and condensation during the flow.
The AOC-4000 series four-link eccentric butterfly valve is typically equipped with a cylinder-type single-acting actuator, but cylinder-type double-acting actuators, electric actuators, and hydraulic actuators can also be selected based on requirements. The minimum shut-off time can reach (2-6) seconds.
Working Principle
The four-link butterfly valve mainly consists of a drive device, valve plate, valve body, valve shaft, linkage system, and shaft end seals. The opening and closing of the valve are driven by the drive device, which moves the valve shaft and the four-link mechanism. The valve shaft rotates to open the valve plate, and when the valve plate is parallel to the pipeline center, the valve is fully open. The reverse rotation of the valve shaft closes the valve plate, and when the valve plate contacts and compresses the valve body's sealing surface, the valve is fully closed.
Body
| Type | Four Lever Offset Buterfly Valves |
| Body Size | NPS 6-64''(DN 150-DN 1600) |
| Disc Form | Four Lever Eccentric |
| Flow to | Flow into the shaft side |
| Characteristics | Liner/On-off |
| Trim material/Trim treatment | See valve material table |
| Body ratings | ASME B16.34 ANSI 150 |
| Body Connections | ·ANSI, EN Double Flanged ·ANSI B16.25 ·API 609 Single Flange-Lug Type |
| Face to Face Dimension | See valve overall size |
| Range ability | Over 100:1(See Cv coefficients table) |
| Bonnet Type | Standard -29 degree Radiation fin -55 degree-566 degree Cryogenic -196 degree-55 degree |
| Packing | PTFE flexible graphite |
Leakage Class | According to API 598 Zero Leakage |
• Maximum diameter of connecting valve body up to DN4000
• Unique four-stem structure design, flat seal design
• External double bearing design prevents medium from entering the bearing and causing blocking
• Drain valve prevents medium corrosion
• High temperature design up to 800 ºC
• API607 Fire Protection Design
• Integral stem design, anti-center shaft out design
• Anti-static design
• Anti-misoperation design
• Multiple sealing structures for option
• Fabricated construction
• In the initial stage od opening and final stage od closing, the disc moves parallel to the body seat provinding a friction-free motion.
• Various seat arrangement
★ Design standard: AP1598API607ASMEB16.34
★ Standard size: NPS12-160"(DN300-DN4000)
★ Pressure class: PN2.5-PN20/ASMECLASS150
★ Applicable temperature: -20 ° C ~ 800 °C
★ Leakage class: ANSIB16.104VI, API598 no leakage
★ Body material: ASTMA105A351CF8M/special alloy, etc.
★ Valve internals material: A479-316;S2205;17-4PH
★ Operation mode: manual, pneumatic, electric, electro-hydraulic, etc.
★Product range can be expanded according to user needs
• Sand Blasting Surface Treatment SA2.5
1. Sandblasted inside and outside of valve body
2. Fine surface after sandblasting, strong paint adhesion
3. If 02 content in medium >23.5%, external sandblasting, internal sandblasting is not required•
1. Standard painted surface temperature resistance up to 450°C, higher temperatures can be treated separatel
2. Two coats of paint 35 micrometers thick for corrosion protection
• Hard Alloy Surfacing on Sealing Surface of Valve Plate
a) The sealing surface of valve plate can be welded with Hastelloy, Stellited gr.6,
b) Tungsten carbide and other hard alloy spraying, hardness up to HRC60-70
SINOCHEM GROUP Petrochemical Incineration Boiler Crossover Four-stem Butterfly Valve (The right figure is used product after 4 years)
Petro China 270,000 tons/year sulfur tail gas standard project
catalytic flue gas turbine outlet butterfly valve instead of water seal tank
Comparison of SINOPEC catalytic flue gas turbine outlet to heat recovery boiler site
Images from the scene of SINOCHEM GROUP Refining and Chemical catalytic flue gas turbine outlet to chimney
SNT Machinery(Qingdao) Co. , Ltd is a producer of control valves, combines manufacturing, designing, sales and services in one. It has high starting point quick development SNT is located in Qingdao, Shandong province with an area for 42000m2, equipped with modern workshop and production equipment. It is a high-tech enterprise with independent intellectual property rights and imported advanced management and production experience. Now it has more than 150 workers, and R&D specialist accounts for 15%, graduates or with higher degrees account for 30%. Depending on high quality production management team and innovative technology research and development, now we produce large quantities of high quality vales used in petrochemical, oil and coal chemical industries. We have a sales value to nearly 100billion in the year 2017.
Now SNT has got the TS special equipment manufactuuring certificate and ISO 9001, and has acquired the net qualification certificate of SINOPEC,CNOOC, PETROCHINA and SINOCHEM. And we have got the National Patent in many technologies. We can design and manufacture all series of valves according to ANSI, API, DIN, BS, JIS standards. Combining the advantages of famous valves all cross the world and with independent research and development, until now we can manufacture all kinds of valves, including GLOBE, High Pressure Boiler Blow-down Valves, High-performance Butterfly Valves, Angle-regulating Valves, Eccentric Rotary Valves, T Three-eccentric Center Butterfly Valves, V Ball Valves, High Wear-resistant Ball Valves, High Pressure Steam Valves, Micro-flow Control Valves, Self-operated Control Valves, Cryogennic Valves tc, Driving form includes manual operation, power-drinven, pneumantic and hydraulic drive. Materials for main parts are A216WCB, A217 WC6/WC9, A351 CF8/CF8M/CF3/CF3M etc. Specification 1/2"~120", working pressure ANSI 150#~2500#, working temperature -196ºC~1100ºC.
Relying on advanced production technology management and qulity assurance system, SNT Valves have been widely used in petrochemical, oil, steel&iron, paper manufacturing and power station industries. Our customers include SINOPEC QILU branch, SINOPEC Qingdao branch, CNOOC Huizhou Refinery, PETROCHINA Guangxi branch, PETROCHINA Ningxia branch, SINOPEC Qingdao Refinery, SINOPEC Qingdao branch, CNOOC Huizhou Refinery, PETROCHINC Guangxi branch, PETROCHINA Ningxia branch, SINOPEC Changling branch, Jinan branch etc.
We make user's profits as our priority, devoting ourselves to the establishment of excellent quality and good brand, Our perfect quality assurance and after-sales systems guarantee that SNT valves join hands with all our customers and creat prosperity.
