Author: Site Editor Publish Time: 2019-03-01 Origin: Site
The function of the check valve is to prevent back flow of the medium in the pipeline. The check valve is an automatic valve type, and the opening and closing member is automatically opened or closed by the force of the flowing medium.
The check valve is only used on the pipeline where the medium flows in one direction, preventing the medium from flowing back to prevent accidents.
Check valve for medium: water, steam, oil, nitric acid, strong oxidizing medium and urea. Widely used in power stations, petroleum, chemical, pharmaceutical, food and other industries. The clamp type check valve is suitable for the nominal pressure PN1.0MPa～42.0MPa, Class150～2500; nominal diameter DN12～1200mm, NPS1/2～48; working temperature -196～540°C for various pipelines, used to prevent The media is reversed. By using different materials, it can be applied to various media such as water, steam, oil, nitric acid, acetic acid, strong oxidizing medium and urea.
Common faults of check valves are:
1. The valve flap is broken
2. The media is reversed.
The cause of the valve flap breaking is
Before and after the check valve, the medium pressure is close to equilibrium and "saw" with each other. The valve flap is often tapped with the valve seat, and the valve flap made of some brittle materials (such as cast iron, brass, etc.) is broken.
The precautionary approach is to use a valve flap as a check valve for ductile materials.
The reason for the media back flow is
1. Sealing surface damage;
2. Pinch the impurities. Repairing the sealing surface and cleaning impurities can prevent back flow.
Check valve maintenance
1 Check valve should be stored in a dry and ventilated room to prevent moisture, rain and rust.
2 The opening and closing parts should be in the closing device during storage or transportation. At the same time, the following work should be done:
a The valve flap should be fixed in the open position.
b The inner end of the through hole is blocked by the foam board, and the port must be tightly closed with a squeaky cover to protect it from dust and rust, to keep the passage clean and the end surface flat;
c Appropriate packaging protection, shockproof and anti-collision;
d Check valves should be placed in a stable position and must not be squeezed from each other.
3 Check valves should be inspected regularly when placed for long periods of time. Every three months, check the dirt and rust on the two channels, the sealing surface, and the protection status of the welded joint. After wiping the dirt and rust, re-apply the anti-rust oil to protect it.