Double Block Discharge Slab Gate Valve with Diversion Hole

The double cut-off slab gate valve with diversion hole is mainly used to cut off the medium. It is a kind of pipeline valve, which is used in many industries, such as natural gas, oil, etc. 

Main features of slab gate valve

• 1. With the structure of diversion hole, the sealing surface of the valve seat is always in contact with the ram when the valve is opened and closed, which can effectively avoid scratching the sealing surface due to medium entering the valve seat, thus improving the service life of the sealing surface of the valve seat, and the valve can play the role of pigging.
• 2. With double sealing structure, the valve is mainly sealed by the soft sealing seat. When the soft sealing seat is damaged, second sealing can be achieved in the metal sealing surface overlaid on the seat.
• 3. Double block discharge function: when the valve is closed, to achieve double block, the inlet and outlet valve seats can seal the pipeline media at both ends of the block valve seat ; when the pressure in the valve cavity is abnormally increased, to achieve double discharge function, the pressure difference acting on both sides of the valve seat will push the valve seat thrust gate to discharge the pressure in the cavity into the pipeline.

Working principles of double block drain valve seat

When the valve is closed, the initial sealing force of the sealing surface is provided by the spring on the valve seat. When the medium pressure entering the upstream and downstream pipelines of the valve is p, to achieve the double cut-off function of the valve, the valve seat is pushed to the ram by the medium pressure difference on the limited annular area. When the pressure in the middle cavity of the valve increases abnormally, the valve seat is pushed away from the ram by the pressure difference between the two sides of the valve seat and the limited annular area, which overcomes the spring force, so that the pressure in the middle cavity can be discharged into the pipeline through the gap between the ram and the valve seat, realizing the function of self discharge of the middle cavity pressure, i.e. double discharge.

Summary of double block discharge slab gate valve

Compared with the ordinary single gate valve, the double cut-off discharge gate valve with diversion hole has the advantages of small friction on the sealing surface of the valve seat, long service life, and low opening effort. When the valve is closed, the valve seats at both ends of the inlet and outlet can be sealed at the same time. When the pressure in the middle cavity increases abnormally, the pressure in the middle cavity can be automatically discharged into the pipeline, so that the valve is more safe and reliable. In some cases, the double block discharge slab gate valve with guide hole can replace the ball valve, so that the application field of slab gate valve is further expanded.

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