The working principle of the check valve: The role of this type of valve is to allow the medium to flow in only one direction, and to prevent the direction of flow. Usually, this kind of valve works automatically. Under the action of fluid pressure flowing in one direction, the valve disc opens; when the fluid flows in the opposite direction, the pressure of the fluid and the self-reclosing valve disc of the valve disc act on the valve seat to cut off the flow. China Marine valve manufacturer shares with you.
The check valve belongs to this type of valve, and it includes a swing check valve and a lift check valve. The swing check valve has a hinge mechanism, and a door-like valve disc freely rests on the surface of the inclined valve seat. In order to ensure that the valve disc can reach the proper position on the valve seat surface every time, the valve disc is designed in a hinge mechanism so that the valve disc has enough swing space and the valve disc is in full and complete contact with the valve seat. The discs can be made entirely of metal, or they can be inlaid with leather, rubber, or a synthetic covering, depending on the performance requirements. The swing check valve is fully open, the fluid pressure is almost unhindered, so the pressure drop across the valve is relatively small. The valve disc seat of the lift check valve is located on the valve seat sealing surface on the valve body. Except that the valve disc can be lifted and lowered freely, the rest is like a stop valve. The fluid pressure causes the valve disc to lift from the sealing surface of the valve seat. The return of the medium causes the valve disc to fall back to the valve seat and cut off the flow. Depending on the conditions of use, the valve disc can be an all-metal structure, or it can be in the form of a rubber pad or rubber ring inlaid on the valve disc holder. Like the shut-off valve, the passage of fluid through the lifting check valve is also narrow, so the pressure drop through the lifting check valve is greater than that of the swing check valve, and the flow of the swing check valve is limited Rarely.
Common faults are:
① The valve disc is broken; ② The medium flows backward.
The cause of the valve disc shattering is that the pressure of the medium before and after the check valve is close to equilibrium and "pulled" with each other. The valve disc is often beaten with the valve seat. Some brittle materials (such as cast iron, brass, etc.) The disc is broken.
The preventive method is to use a check valve with a flexible disc.
The reasons for media backflow are:
① The sealing surface is damaged; ② Impurities are trapped. Repairing sealing surfaces and cleaning impurities prevents backflow.
Our company also provides Dual Plate Check Valve.