ball valve

First, the structure characteristics of full welded ball valve
1.1 all welded structure
Ball valve body consists of six parts forging shell assembly after welding and become, compact structure, the whole ball valve. The current domestic production of the use of large diameter ball valve for fission three panel structure, adopts bolt connection between the parts. Compared with three type ball valve, in under the same intensity of full welded ball valve forgings of wall thickness can be thin. Valves can reduce weight a quarter, and at the same time of pipe bending and compression resistance; Due to cancelled the valve flange and bolt, shape size decreases, and with the call also eliminates the potential leakage passage. In addition, the body welding structure internal curve smooth. Keep the lubrication and pipeline connection no dead Angle, good medium flow.
 
1.2 box axis fixed ball design
Ball valve based on sphere form can be divided into two kinds of fixed and floating ball. Domestic products general structure of the floating ball, ball under the pressure of medium sphere are compressed in the outlet seal surface, achieve closed, import and export pressure difference is bigger, once the body due to the torque is very often it is difficult to open. All welded ball valve adopt high strength steel stem satin, PTFE (polytetrafluoroethylene) by outsourcing stainless steel bearing do support smooth rotation accuracy. Due to pivot support stem can absorb piping medium pressure that generates the thrust, and can reduce the friction between the valve ball and seat, so even under full differential pressure, the operation of concave door torque requirement is very low, still ball valve switch freely.
 
1.3 rotating seat design
When the ball valve on close to close or just opens, the narrow point position between the valve ball and seat (9 o 'clock position) for gas cut by throttle into high-speed turbulent under high speed, become the most serious regional seat seal wear. Finally cause leakage. Size 12 (or more) CAMERON (CAMERON) ball valve USES a unique rotating seat. Every time they open or close the valve. The upstream and downstream seat is on the valve ball dial plucked rotating 15 degrees Celsius, so the valve seat sealing surface in turn by the gas flushing, the valve open or close the same parts after the 12 times to flushing again, the entire seat wear uniform, extended service life greatly. Conventional ball valve seat is fixed, the long running after damaged parts is also fixed the seat will often cause the drain. On the other hand. Pipeline in operation after a period of time some harmful sediment can accumulate on the seat ring, caused by the conventional ball valve jammed or can't normal seating, while rotating seat in turns to remove foreign bodies on the surface of the seat.
 
1.4 the valve stem and secondary emergency greasing seating
PFFE stem the upper area of the sealing material is a kind of low friction resistance to ageing material, long service life. (size (or more) of full welded ball valve stem is also equipped with sealing grease injection system, once the ball valve seat between enters the foreign body and damage the sealing surface, can still through the secondary injection of special sealing grease maintain seating. Conventional ball valve does not have sealing grease injection structure. Once the sealing surface damage internal leakage occurred, only replacing the entire ball valve.
 
1.5 automatic internal relief valve cavity pressure and double lumen partition put pressure
Sealed ball valve is to adopt double seat of upstream and downstream of the partition, but a long running seat cannot avoid wear and tear; Upstream seat when the valve is closed, there may be some leakage, leakage of the medium into the valve ball lumen. Special design of the downstream seat can effectively avoid the valve ball midplane overpressure, once the valve cavity pressure more than the downstream pressure is 138 kpa, the downstream seat will be pushed away from the ball, make the pressure relief in the downstream piping. Ball valves installed with lumen tube connected with pressure, and will put pressure pipe lead to the ground, regardless of whether the valve is in full open or close position, all can open the valve cavity shutoff valves, discharge midplane pressure. Pressure is detectable by releasing midplane seat sealing performance.