Linuo Knife Gate Design Advances

The Linuo knife gate is an economical, high performance knife gate valve used in pulp and paper making, refining, wastewater and water treatment, mining, and chemical fiber industries.

It has the following advanced features:

1) A super thin body design and compact construction, providing easy installation.

2) The seats movable design with a spring-loaded O-ring serves to provide self-compensation to normal seat wear, resulting in long term service life. Excellent seal tightness is upheld throughout a prolonged life cycle. Metal seated, EPDM seated and PTFE seat designs are available for various process conditions.

3) The disk bottom provides a knife shaped design with strong cutting force, particularly applicable for pulp media. The disk guide is hard chromium plated after a perfect surface grinding allowing high abrasion and corrosion resistance.

4) PTFE guides insure tight gate to body contact with low friction and no damage to the gate. Small machined transitions at the port bottom prevent residue build-up and reduce downtime.

5) A variety of port designs are available for various process conditions, such as 3 port, triangle port, hexagonal port, and others.

6) The knife gate valve can be mounted with pneumatic and electric actuators control systems for used in automatic control systems in a variety of industries.

Check out this video about the Linuo Knife Gate valve:

Basic Information on Trunnion Ball Valves

A trunnion ball valve is a valve where the ball is physically supported in the body and kept directly in-line with the valve stem. In a trunnion design, there is a single, consistent centerline between the ball and the stem. When under load, the ball does not change position or get pushed or in either direction. A seating surface inside the valve supports the ball, handling the pressure and managing the end loads.

The valve seats on either side of the ball have spring loading on the ball, thus making the trunnion ball valve a true bi-directional sealing ball valve.

For use in severe service, where a metal seated trunnion ball valve is required, seat selection is critical. The physical characteristics of the seat must be able to withstand the application conditions (such as elevated temperatures). Therefore, elastomers or “soft seats” like Viton or PTFE should not be used.

For critical applications a constant, static seal between the seat and body with a dynamic seal between the seat and ball is needed. The seal between seat and body must be a temperature tolerant material such as Grafoil or the like, to withstand the elevated temperatures. The dynamic seal between seat and ball is metal-to-metal, with a variety of hard coating materials such as Hard Chromium, Nickel Boron, Tungsten Carbide, Tungsten Chromium Carbide, or Chromium Carbide.

The valve seat is spring loaded on the ball via upstream pressure providing better sealing on the upstream side of the ball. Trunnions hold the ball in place and the valve seat positions to tightly seal the ball.