American Standard API Check Valve
The check valve is a valve that can automatically prevent the backflow of the fluid. It is used in the pipeline system. Its main function is to prevent the backflow of the medium, to prevent the pump and its driving motor from reversing and the medium in the container to discharge.
Check valves are generally divided into lift, swing, disc and diaphragm types, but the most common is the swing check valve.
The swing check valve is a disc that rotates around the axis, and its fluid resistance is generally smaller than that of the lift check valve. It is suitable for occasions with larger diameters. According to the number of discs, swing check valve can be divided into three types: single disc swing type, double disc swing type and multi disc swing type check valve. Single flap swing check valves are generally used in medium caliber applications. When using a single flap swing check valve for large-diameter pipelines, in order to reduce the water hammer pressure, it is best to use a slow-closing check valve that can reduce the water hammer pressure. Double flap swing check valve is suitable for large diameter pipelines. The wafer swing check valve has a small structure and light weight, and is a kind of check valve with rapid development.
The structure of the disc check valve is similar to the butterfly valve. Its structure is simple, the flow resistance is small, and the water hammer pressure is also small.
Diaphragm check valves have various structural forms, all of which use diaphragms as opening and closing parts. Due to their good waterproof hammer performance, simple structure and low cost, they have developed rapidly in recent years. However, the operating temperature and pressure of the diaphragm check valve are limited by the diaphragm material.
1. Structural features
The valve flap can be automatically closed under the action of gravity, preventing the medium from flowing back.
2. Self-sealing structure
The middle flange sealing ring can play a sealing role under the action of medium pressure.
3. Wafer double flap swing check valve
The water hammer pressure is small, the valve disc travel is short, the spring is assisted to close, and the switch is fast. The structure is short in length, small in size and light in weight.
