Check valve is the popular valve which widely used in different industries, today WESDOM will introduce to you some check valves.
A check valve whose disc slides along the vertical centerline of the valve body. Lifting check valves can only be installed on horizontal pipelines. Balls can be used for discs on high-pressure small-diameter check valves. The shape of the valve body of the lift check valve is the same as that of the globe valve (it can be used in common with the globe valve), so its fluid resistance coefficient is larger.
Its structure is similar to the globe valve, and the valve body and disc are the same as the globe valve. The upper part of the valve disc and the lower part of the valve cover are machined with guide sleeves. The valve disc guide can be freely lifted and lowered in the valve guide. When the medium flows downstream, the valve disc is opened by the thrust of the medium. It falls vertically on the valve seat to prevent the reverse flow of the medium.
The direction of the medium inlet and outlet channels of the straight-through lift check valve is perpendicular to the direction of the valve seat channel; the vertical lift check valve has the same direction of the medium inlet and outlet channels as the valve seat channel, and its flow resistance is smaller than that of the straight-through type.
The disc of the swing check valve is disc-shaped and rotates around the shaft of the valve seat passage. Because the passage in the valve is streamlined, the flow resistance is smaller than that of the lift check valve. It is suitable for large-diameter occasions with low flow rate and infrequent changes in flow, but it is not suitable for pulsating flow, and its sealing performance is not as good as that of lifting type.
The swing check valve is divided into three types: single-lobe type, double-lobe type and multi-half type. These three types are mainly divided according to the diameter of the valve.
The butterfly check valve is similar in structure to the butterfly valve. The main difference is that the butterfly valve must be driven by external force as a shut-off valve, while the butterfly check valve is an automatic valve and does not require a driving mechanism. When the medium stops flowing or flows back, the disc rotates to the valve seat by its own weight and the action of the backflow medium.
This check valve can be used on both horizontal and riser pipes and is usually wafer mounted. Under the action of fluid pressure, the two discs rotate around the pin shaft against the spring force, and the opening state is a bit like a "">" sign. There should be some straight pipe sections at the inlet and outlet of the valve, because the valve disc must have a certain space for rotation.