When installing check valves, it is necessary to ensure their proper functioning from various aspects such as direction, location, piping conditions, auxiliary devices, etc. to avoid leakage, failure or system malfunction due to improper installation. The following are detailed precautions:

Installation direction: strictly follow the medium flow direction

Core principle: check valve valve body is usually marked with an arrow, the direction of the arrow must be completely consistent with the direction of media flow, prohibit reverse installation.

Example: pump outlet check valve, the arrow should point to the direction of the water flow away from the pump, to prevent the shutdown of water backflow back to the pump.

Consequence: reverse installation will lead to the check valve can not be closed, the medium continues to flow backward, may trigger the pump reversal, system pressure imbalance and other issues.

Piping conditions: Ensure that the installation environment is suitable

Pipeline cleanliness: Thoroughly clean the welding slag, rust, impurities, etc. in the pipeline before installation, to avoid foreign objects stuck between the valve flap and the valve seat, resulting in sealing failure or flap jamming.

Pipe diameter matching: the nominal diameter of the check valve should be the same as the diameter of the pipeline, if you need to change the diameter, you need to use the transition of the reducer pipe fittings, to avoid sudden changes in the diameter of the pipeline resulting in fluid turbulence, affecting the action of the valve flap.

Support fixed: large diameter check valves (such as DN100 or more) need to set up an independent bracket in the pipeline, to avoid the valve weight on the pipeline caused by stress, affecting the sealing performance.

Auxiliary device: according to the demand with accessories

Filter: If the medium contains particles of impurities (such as sewage, slurry), it is necessary to install a Y-type filter upstream of the check valve to prevent impurities from clogging the valve flap or abrasion of the sealing surface.

Bypass valve: In high-pressure systems or large-diameter pipelines, a bypass valve can be installed next to the check valve to facilitate the isolation of the valve during maintenance or to balance the pipeline pressure during commissioning.

Pressure gauge / thermometer: install monitoring instruments upstream and downstream of the check valve to monitor the pressure and temperature changes in real time, so that it is easy to judge the valve's working status (e.g. whether the pressure drop is too large due to blockage).

Installation points for special scenarios

1. Vertical pipeline (medium flows from bottom to top)

Swing check valve flap rotation axis needs to be kept horizontal, to avoid tilting due to gravity leads to delayed closure; lifting check valve need to ensure that the valve flap can fall back smoothly under the action of gravity.

2. High / low temperature media system

High-temperature occasions (such as steam pipelines) need to choose the metal sealing surface of the check valve, and to ensure that the valve body material temperature; low-temperature occasions (such as liquefied gas pipelines) need to use low-temperature steel, to prevent the flap from freezing or the valve body brittle cracks.

3. easy to produce water hammer system

When the pump suddenly stops, the medium backflow may trigger water hammer, it is recommended to use spring loaded check valve (fast closing speed), or install water hammer eliminator downstream of the valve.

Inspection and commissioning after installation

Manual test: After installation, manually push the valve flap (rotary opening type can swing the valve flap, lifting type can move up and down the valve flap), check whether the action is flexible, no blocking phenomenon.

Sealability test: pass the medium in the positive direction, observe whether there is leakage in the downstream; apply pressure in the reverse direction (e.g. air pressure test), check whether the sealing surface of the valve seat is tight.

Operation monitoring: after the system is started, listen to the valve to see if there is any abnormal noise (such as frequent impact sound of the valve flap), check whether there is any leakage in the connection, and shut down the machine in time for maintenance if any problem is found.

Yantai Valtone Valve Co., Ltd.

Email: 

liujun@valtone-valve.com

carrie@valtone-valve.com

Tel: 

+86-535-6391338
Cell Phone: 

+86-18660599666

Address:

No. 13, Wuhan street, Bajiao industry park, Yantai ETDZ, Shandong, China