Excellent Function：

• assemble structure no manmade installation error.
• reliability in the system changing period to supply safety allowance for temperary expansion when power on or off.
• reliable and stable sealing under vibrating working condition.
• outstanding discharge control ability of contact side design.
• only need to exchange spare part package including movement circle, O ring and spring, no need to exchange metal parts, which lower down maintenance fee as much as possible.

Structure：

• whole O circle moves or fixed in the nonmetal or non-weariness surface.
• friction side sealing side being accurately straight with axis.
• entirely transmission pin without danger of falling.
• with hydraulic balance priniple in the contact surface to produce less friction heat.
• washing interface (selectable) can turn all around faciliating connection.
• spring is separated from liquid to avoid erosion and block.
• adjustable shield without any change to match with conventional bolt.
• automatic blocking circle to reach outstanding concentric.
• core fixing hoop to simplify installation and daily maintenance.