Brief introduction and description of swing check valve

Check valve is also known as one-way valve or check valve. Its function is to prevent the backflow of medium in the pipeline. The bottom valve of water pump is also a check valve. The opening and closing parts automatically open or close by the medium flow and force, so as to prevent the backflow of medium. The valve is called check valve. The check valve belongs to the automatic valve category. The check valve is mainly used on the pipeline with unidirectional flow of medium, and only allows the medium to flow in one direction to prevent accidents.

According to the structure, the check valve can be divided into lift check valve, swing check valve and butterfly check valve. Lift check valve can be divided into vertical check valve and horizontal check valve. Swing check valve is divided into single disc check valve, double disc check valve and multi disc check valve. Butterfly check valve is a through check valve. The above check valves can be divided into three types in connection: threaded check valve, flange check valve and welded check valve.

The installation of check valve shall pay attention to the following matters:

1. Do not make the check valve bear the weight in the pipeline. The large check valve should be supported independently, so that it is not affected by the pressure produced by the pipeline system.

2. During installation, the direction of medium flow shall be consistent with the direction of arrow on the valve body. 3. Lift type vertical disc check valve shall be installed on the vertical pipeline. 4. Lift type horizontal disc check valve shall be installed on horizontal pipeline.

Nominal pressure or pressure level of check valve: pn1.0-16.0mpa, ANSI class 150-900, jis10-20k, nominal diameter or caliber: dn15-900, NPs 1 / 4-36 connection method: flange, butt welding, thread, socket welding and other applicable temperatures: - 196 ℃ - 540 ℃ body material: WCB, zg1cr18ni9ti

ZG1Cr18Ni12Mo2Ti、CF8(304)、CF3(304L)、CF8M(316)、 CF3M(316L)、Ti。 With different materials, the check valve can be applied to water, steam, oil, nitric acid, acetic acid, oxidizing medium, urea and other media.

The check valve only allows the medium to flow in one direction and prevents the flow in the opposite direction. Generally, the check valve works automatically. Under the action of the fluid pressure flowing in one direction, the valve disc opens; when the fluid flows in the opposite direction, the fluid pressure, the self weight of the valve disc and the valve disc act on the valve seat to cut off the flow.

When the swing check valve is fully open, the fluid pressure is almost unimpeded, so the pressure drop through the valve will be smaller.

The disc seat of the lift check valve is located on the sealing surface of the valve seat on the valve body. Except that the valve disc can be lifted freely, the rest of the valve is like a globe valve. The fluid pressure makes the valve disc lift from the sealing surface of the valve seat. The backflow of the medium causes the valve disc to fall back to the valve seat and cut off the flow.

According to the applicable conditions, the disc can be made of all metal mechanism, or the disc holder can be inlaid with rubber pad or rubber ring.

Like the stop valve, the passage of fluid through the lift check valve is narrow, so the pressure drop through the lift check valve is larger than that of the swing check valve, and the flow of the swing check valve is limited very little.