What are the common failures of check valves?

 What are the common failures of check valves?

Check valve faults and solution:

Check valve refers to a valve whose opening and closing part is a circular disc and acts by its own weight and medium pressure to block the backflow of the medium. It belongs to the automatic valve category, and the movement mode of the valve disc is divided into lift type and swing type. The common faults are as follows: the lifting valve disc, the lifting is not working; the swing rocker mechanism is damaged; the medium flows back.

1. Lifting valve disc, the lifting is not working

Reason 1: The drain hole on the valve disc shaft and guide sleeve is blocked, resulting in a damping phenomenon, which causes the valve disc to not work smoothly

Treatment method: Regular cleaning, and media with high viscosity and abrasive particles should not be used

 

Reason 2: Improper installation or assembly, making the valve disc crooked

Treatment method: Check the processing quality of the parts, the installation or assembly should be correct, and the valve cover should not be skewed in the middle

 

Reason 3: The clearance between the disc shaft and the guide sleeve is too small

Treatment method: The clearance between the valve disc shaft and the guide sleeve is moderate, and the influence of temperature changes and abrasive particle invasion on the valve disc lift should be considered.

 

Reason 4: The valve disc shaft is worn and blocked

Treatment method: regular maintenance

 

Reason 5: Failure of the preload spring

Treatment method: regular inspection and replacement

 

1. The swing rocker mechanism is damaged

Reason 1: The pressure before and after the valve is close to or fluctuates greatly, so that the valve disc and other parts are damaged by repeated flapping.

Treatment method:The operating pressure should be stable, and when the operating pressure is unstable, cast steel valve discs and steel rockers should be selected.

 

Reason 2: The rocker mechanism is not assembled correctly, resulting in the phenomenon that the valve disc falls up and down

Treatment method:Before use, it should be colored to check the tightness of the sealing surface

      

Reason 3: Loose or worn connection of rocker, disc and mandrel

Treatment method:The assembly should be firm, the quality meets the technical requirements, and the regular maintenance

 

Reason 4: The joystick is deformed or broken

Treatment method:Manufacturing quality meets technical requirements, regular inspection

 

1. Medium backflow

 

Reason 1: The non-return mechanism is not working or damaged

Treatment method:Regular cleaning, it is not suitable to use media with high viscosity and high abrasive particles; check the processing quality of parts, installation or assembly should be correct, the valve cover should not be skewed in the middle; the clearance between the valve disc shaft and the guide sleeve should be moderate, and temperature changes and abrasive particle intrusion should be considered. Effect on valve disc lift; regular inspection and replacement

   

Reason 2: The sealing surface is damaged and aging

Treatment method:Correct selection of sealing surface materials, regular maintenance, and regular replacement of rubber sealing surfaces

 

Reason 3: The sealing surface is not closed for a long time, and the dirt is attached to it, which cannot be well sealed

Treatment method:For media containing many impurities, a filter or a sewage pipe should be set before the valve

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Complete solutions for Industrial valves