The main advantage of the lift check valve is its simple construction. Since the conical disc is the only moving part, the valve is durable and requires little maintenance, and because it is a metal seat, there is little wear.
The double offset butterfly valve is characterized in that the shaft center of the valve stem is offset from both the center of the disc and the center of the body. The double offset effect allows the disc to be quickly disengaged from the valve seat after the valve is opened, which greatly eliminates unnecessary over-squeezing and scraping of the disc and the valve seat, reduces the opening resistance, reduces wear and improves the seat life.
The two eccentricities of the double offset butterfly valve refer to the eccentricity of the rotating center line of the disc and the eccentricity of the sealing line and the eccentricity of the center line of rotation of the disc and the center line of the channel.
Further improved molding on the basis of the single offset butterfly valve is currently the most widely used double offset butterfly valve. The structural feature is that the stem axis is offset from the center of the disc and from the center of the body.
The offset butterfly valve is divided into single offset butterfly valve, double offset butterfly valve, and triple offset butterfly valve. A butterfly valve whose valve stem axis is at the same time deviated from the center of the disc and the center of the body, and whose sealing pair is a slanting vertebra is called an offset butterfly valve.
The butterfly valve application range:his manual contains manual, geared, electric and pneumatic operating butterfly valves with nominal diameters from DN50mm to 1600mm (2"~64") and nominal pressures from PN1.0MPa to 4.0MPa (ANSI CLASS150~300).
The double offset butterfly valve is further improved on the basis of a single eccentric butterfly valve. The structural feature is that the stem axis is eccentric from the center of the disc and from the center of the body.
The ball of the floating ball valve is floating without a mounted shaft. Under the action of the medium pressure, the ball can generate a certain displacement and press on the sealing ring at the outlet end to ensure the sealing of the outlet end, which is a single-sided forced seal.
The valve flap of the swing check valve is disc-shaped and rotates around the shaft of the valve seat passage. The flow passage is streamlined and the flow resistance is smaller than that of the butterfly check valve. It is suitable for low flow rate and irregular flow.
The plug valve is a closing or plunger-shaped rotary valve that opens or closes by rotating the passage port on the valve plug 90° degrees or the same as the passage port on the valve body.Plug valve is difference from knife gate valve. The plug of the plug valve may be cylindrical or conical shape.