Improvement of ball valve door seal

A, the present situation and the ball valve door seal analysis cast stone ball valve door is ideal in the ash pipe opening and closing device, its sealing quality directly affect the quality and the service life of the valve gate. Used O shaped rubber seal structure form, that is, on the shaft processing O ring is put inside the ring groove, then assembled into a set of parts processing out of the hole and shaft and hole sealing, the sealing performance of the structure depends on the amount of interference when the design, namely the O ring compression and machining precision of hole and shaft parts. Interference quantity is too small, sealed performance is poor, the amount of interference is too large, easily when assembling crowded bad O ring, seal failure. The sealing structure is simple, easy assembly. But if the shaft, hole machining accuracy is not high, or difficult to improve the machining precision, in addition to basic sealing performance is difficult to guarantee or difficult to further improve the accuracy, its main drawback is that the sealing material, this seal structure is applicable in the cylinder, hydraulic cylinder, cast stone used in ash water ball valve door seal is difficult to ensure the sealing performance. The reason is that ball valve door switch belongs to the part of the transformation of the back, often need to 90 & deg; The switch. Because for clearance fit between the valve stem and valve body, have a certain gap, valve door in medium switch in the sphere of large thrust, inevitably produces a certain inclination to make the valve rod of the valve rod to side, the side is badly worn, contains a lot of suspended matter and ash water erosion on sealing ring. Cause the valve rod part O ring life cycle is short, leak phenomenon often happens, also caused certain effects in the field environment, therefore decided to improve the sealing structure forms and materials, the improved main starting point is the assembly in the shaft and hole, can be adjusted through the compression quantity and don't have to greatly improve the shaft, hole machining precision can be guaranteed effectively sealed. Second, the ball valve door structure improvement and abrasive design 1, X X to seal ring structure surrounded by sealing surface, are on the outside of the sealing ring in lubricating groove, this kind of structure is better than that of O ring, installation precision is low, the use of good reliability, no maintenance, low prices, can also through the gasket compression quantity adjustment, has been widely used in various pressure levels of cast stone gate valve sealing, can effectively prevent the occurrence of leakage phenomenon, greatly extend the service life of the valve gate, improve the reliability of the valve gate. 2, X X to seal ring material, material using polyurethane ( CPU) Materials, can effectively solve the problems existing in the traditional O ring. Type casting polyurethane is now on the international comparison by a sealing material, the modulus of elasticity is big, physical and mechanical performance is good, can bear bigger impact load, and polyurethane has been basically settled the problem of hydrolysis resistance, heat resistance level is in constant increase, greatly expands the application fields of the polyurethane. With a molded polyurethane x-shaped seal production, the craft simple, the manufacturing cost is low. Their level of pressure can reach 60 mpa is even higher, effect of pressure also is quite good, basic can reach zero leakage. 3, ball valve door sealing principle, its working principle: when tightening bolts, gland downwards pressure adjustment gaskets, by extrusion V packing cushion, make x-shaped seal lips, in the outside lip tiejin shaft and hole sealing surface at the same time, guarantee the reliability of the seal, the sealing performance depends on the main assembly screw down the bolt clamping force, the relationship between shaft and hole size accuracy without too much. 4, grinding tool designed to ensure the use requirement of products, comply with the design requirements; Mold release, qing mould, easy to operate; Manufacturing cost is low; Abrasive materials for 45 steel; Press 1 shrinkage rate. 5% ~ 1. 7% design; 10° Slope position without flash, products guaranteed accuracy, high yield; Abrasive tool consists of upper die, die, die in. 5, packing chamber size packing chamber according to ball valve door pressure and diameter size decided dressing quantity, width is determined by the size of the shaft. Pressure to zero. 6 to 2. 5 mpa, DN250mm prevent an X under seal; 2. 5 ~ 10 mpa, the placement of more than 12 two X sealing ring. Packing chamber by dressing pad size depth, pressure transfer ring, x-shaped seal height. 6, pressure transmission loop pressure transmission loop is set up in high pressure and large diameter, it is installed between the two groups of X ring, its main function is passed the above pressure, change x-shaped seal bearing state, make X ring stress and radial deformation, reach the sealing performance. 7, finite element analysis of X of X ring ring is a kind of lip seal, with pressure ring ( The packing gland) And the bearing ring ( Packing cushion) Combined, it can effectively prevent media leaks. 8 X, X ring force analysis force is through pressure seal ring ( The packing gland) Pressure is passed to the X ring, sealing ring at the bottom of the bearing ring ( Packing cushion) The form of three strength, axis force uniform with the sealing face of valve port, and can get ideal sealing effect. By improving the end of the three, about the ball valve door seal, valve door structure more reasonable and more reliable sealing, save raw materials, reduce the cost, and improve the service life and retrofit is fast, less investment, to satisfy the users' needs.