Pressure balanced plug valve

In order to reduce the conventional hard-sealed torque plug valves are often used pressure balanced plug valves. Pressure balanced plug valves in addition to conventional oil-lubricated plug valves with the characteristics, there are the following characteristics:
A. pressure balanced plug valves of cocks for the installation of pyramidal inversion. Cocks of the upper cone of a non-return valve.
In the valve closed, Cone cocks up and down due to poor cross-sectional area, the high pressure seal oil into the plug so that by the upward lifting force to the valve plug and the sealing surface can be sealed better.
B. Open the moment in the valve, valve body cavity under the pressure and medium pressure pipelines balance, on the high-pressure chamber sealed by the oil so plug thrust downward, with the body of cocks Cone sealing surface between the small gap , when the rotating plug will effectively reduce the torque. Can also be sealed to protect vice.
C. In the high-temperature conditions, cocks, thermal expansion can be absorbed through the take-off and landing to avoid the death sealed card.
Oil sealed plug valves hardware, although the proper lubricating oil to reduce the torque headstock, but it may form a contaminated medium. Thus the actual choice of sealing lubricant condition.