seated ball valves, gate valves and orbit ball valves. ... The first. C-wear resistant ball valves have been in operatio
Would you like to receive a hardcopy of this magazine's full publication? Please include the month and year of publication and contact Mrs. Erica Riethorst at
[email protected]
Keywords: Balancing valve • Ball valves • Coal gasification
Oil & Gas
Applications of C-wear resistant ball valve for coal gasification devices An alternative valve with a longer service life and resistance to wear-and-tear for coal gasification devices is sought after by many. This valve exists. Read on as Changming Li discusses the C-wear resistant ball valve.
By Changming Li, Shandong Afa Flow Control Co., Ltd.
T
he valves commonly used in terms of access to chilling pumps, high-pressure water back pumps and low-pressure water back pumps in coal gasification devices, and lye medium (easy-to-accumulate dregs) are metalseated ball valves, gate valves and orbit ball valves. Opening and closing frequency for these applications is low, every two months or less. Long term inaction leads to extremely serious scaling in the valve. When the ball valve is fully open, dead space between the valve body and the ball will form heavy scaling on the surface of the ball body so that, possibly, even the switch may not work. Dregs accumulate at the bottom of the gate valve so that the flashboard cannot be put in place. Although the orbit ball valve can be closed, material adhering on the sealing surface cannot be removed and any leakage will be very serious. Basically, the three kinds of valves mentioned above should be dismounted for maintenance after only two to three operations. These problems are very challenging for the device operator.
Serious scaling of the valve The C-wear resistant ball valve adopts a double asymmetric structure. Its ball body only has contact with the valve seat during sealing. The rest stroke has zero friction and wear. It is easy to open and, when closing, gradual movement of the ball surface for the valve seat has a shearing action against material adherence on the ball surface so as to achieve a self-cleaning function. When the valve is fully open there is nothing to obstruct the flow in the valve cavity. The design is full bore and there is no stagnation zone for material
The alternative The C-wear resistant ball valve can easily solve these problems. Not only does it guarantee flexibility of switch motion, but also reliable and safe sealing. www.valve-world.net
to collect in. The medium is always able to flow so that the problem of medium and accumulative dregs can be effectively resolved. When the valve closes there is no dead space. In terms of sealing, the C-wear resistant ball valve adopts torque sealing due to its double asymmetric structure and selfsealing against pressure from the medium from the spring loaded fluctuation valve seat, so that reliable sealing can be ensured. The valve adopts an upper and lower supporting axle structure and the valve stem is not affected by pressure from the medium but only has to cope with fully flowing medium when open. The ball surface is metallurgically melted and spray-welded with a nickel-base alloy. The bond strength of the spray-welded layer and the base material is high, which can meet the wear resistance requirement of the sealing face of the valve seat. The contact part of the upper and lower supporting axle and ball body is spraywelded with cemented carbide so that the long-term friction motion between the ball and the supporting axle will not generate wear. The C-wear resistant ball valve also has automatic compensation and a long service life of five times longer than that of other valves.
Structure of the C-wear resistant ball valve January / February 2012
1
Oil & Gas
At present The C-wear resistant ball valve is currently being applied for access to chilling pumps, high-pressure water back pumps and low-pressure water pumps back pumps in coal gasification devices of many domestic companies, also in lye and black water pipelines. Customer feedback regarding operating conditions is good. The first C-wear resistant ball valves have been in operation for 13 months now and continue to be fully serviceable. More and more coal gasification enterprises are electing to fit these valves to replace standard metal-seated ball valves, gate valves and orbit ball valves.
About the author Changming Li is Manager of the Technology Department at Shandong Afa Flow Control Co., Ltd. He is also an Assistant Chief Engineer and was responsible for developing the C-wear resistant ball valve. Additionally Mr Li was involved in the design of the coal chemical valve and is familiar with the application conditions of the valve for coal gasification devices. Field applications of the C-wear resistant ball valve
2
January / February 2012
www.valve-world.net
