Overview of the check valve

Opening and closing parts by the media flow and power to open or close their own to prevent media backflow valve called the check valve. Check valves are automatic valves, mainly used for medium flow of one-way pipe, only allow medium to flow in one direction to prevent accidents. Structure Check Valve (Check Valve): According to the structure, can be divided into lifting check valve, swing check valve and butterfly check valve three. Lift check valve can be divided into vertical and horizontal two. Swing check valve is divided into single-valve, double-valve and multi-valve three. Butterfly check valve is straight-through, the above types of check valve in the connection form can be divided into thread connection, flange connection and welding three. Installation of Check Valve Installation should pay attention to the following matters Top 1, do not make the check valve in the pipeline to bear weight, large check valve should be independent support, so that it is not affected by the pressure generated by the pipe system. 2, when installing, pay attention to the direction of the flow of the medium should be consistent with the arrow direction of the body ticket. 3, vertical drop-check valve should be installed in the vertical pipe. 4, lift-level flap check valve should be installed on the level of the pipeline. Check Valve Category: A, according to the material classification (check valve body material) 1. Cast iron check valve 2. Brass check valve 3. Stainless steel check valve Second, by functional classification 1. NRVZ mute Check valve 2.NRVG quiet check valve Check Valve (Check Valve): is to automatically stop the fluid back to the valve. The check valve flap opens under fluid pressure and fluid flows from the inlet side to the outlet side. When the pressure on the inlet side is lower than on the outlet side, the valve flap closes automatically under the effect of fluid pressure difference and gravity itself to prevent fluid backflow. Check Valve (Check Valve): Generally divided into lift, swing Kai, butterfly and diaphragm type, and other several. Lift check valve structure is generally similar to the cut-off valve, the valve flap along the line for lifting movements, reliable action, but larger fluid resistance, suitable for light small caliber occasions. Lift check valve can be straight and vertical two. Straight-through lift check valve can only be installed in the horizontal pipe, and vertical lift check valve is generally installed in the vertical pipe. Swing check valve flap for rotation around the axis of rotation. The fluid resistance is generally less than the lift check valve, which is suitable for larger diameter occasions. Swing check valve according to the number of valves can be divided into single-valve swing type, double-swing type and multi-swing swing type three. Single-flap swing check valve is generally suitable for medium-diameter occasions. Selection of large-diameter pipe single swing check valve, in order to reduce water hammer pressure, it is best to reduce the pressure of the water hammer slow closing check valve. Double valve swing check valve for medium and large diameter pipe. Double-flap swing check valve on the structure of small, light weight, is a fast-growing check valve; multi-valve swing check valve for large-diameter pipe. Butterfly check valve structure similar to the butterfly valve. Its simple structure, smaller flow resistance, water hammer pressure is also smaller. Diaphragm check valve has a variety of structural forms, are used as the opening and closing the diaphragm, due to its good waterproof hammer, simple structure, low cost, rapid development in recent years. However, the use of diaphragm check valve temperature and pressure diaphragm material restrictions. 3.NRVR silent check valve 4.SFCV rubber valve check valve 5.DDCV double valve