These valves are installed where existing pulsant or static high pressures are present.
The benefit which a pressure balanced Plug gives is the equalized pressure between the Plug and upper and lower body chambers.
Pressure is balanced by two holes in the plug connecting the plug port with lower and upper cavities.
The hole in the lower end is a simple connecting passage whilst the hole in the upper end is provided with a check valve so the pressure is always equal to the one in the large end cavity and it is always equal to or greater than the line pressure in the small end cavity.
Some advantages are:

• Easy mainteneance even after long time in open/closed position
• In case of locking of the Plug with the body,it is possible to release by injecting lubrificant through the greaser with the valve in service
• Tightness of the stem is assured by antifriction ring fitted between stem and body. Two gaskets fitted between stem and valve body guarantee against any leakage through the stem
• Tightness of the operating system is assured by the ball check devices on the lubrification duct
• When required the valve is equipped with double operating grease injectors suitable for lubricating gun and lubrating sticks.