When installing flanged check valves, the following precautions should be taken to ensure their proper operation and long-term use:

1. Preparation before Installation

• Inspect the valve: Ensure that the valve has not been damaged during transportation and that there are no foreign objects inside the valve body.
• Clean the pipeline: Clean debris such as weld slag and rust from inside the pipeline to prevent them from entering the valve body.
• Verify parameters: Check the pressure, temperature, material, and other parameters on the valve's nameplate to ensure they meet the requirements of the working conditions.

2. Installation Position and Direction

• Flow direction marking: Ensure that the arrow marking on the valve is consistent with the flow direction of the medium in the pipeline.
• Vertical installation: Check valves are typically installed vertically, with the valve disc free to open and close. When installed horizontally, ensure that the valve disc can move freely.

3. Flange Connection

• Align flanges: Ensure that the flanges of the pipeline and valve are aligned to avoid offset or stress concentration.
• Flange gasket: Select the appropriate gasket material and place it correctly between the flanges to prevent leakage.
• Bolt tightening: Tighten the flange bolts uniformly in a diagonal sequence, gradually increasing the force to ensure uniform stress on the flange and prevent deformation.

4. Avoid Stress

• Pipeline support: Install appropriate supports before and after the valve to prevent the weight and stress of the pipeline from concentrating on the valve.
• Reduce vibration: In pipeline systems with significant vibration, take measures to reduce vibration transmission to the valve and extend its lifespan.

5. Testing and Commissioning

• Seal test: Conduct hydrostatic or pneumatic testing after installation to check the sealing performance of the flange connections and inside the valve.
• Function test: Confirm that the check valve can open and close normally during medium flow and stoppage.

6. Regular Maintenance

• Regular inspection: Regularly inspect the tightness and sealing performance of the flange connections to prevent loosening and leakage.
• Clean the valve body: Clean the inside of the valve body when necessary to prevent debris accumulation that could affect valve performance.
• Lubricate components: For check valves requiring lubrication, regularly inspect and add lubricant to ensure flexible valve disc movement.

7. Special Working Condition Considerations

• High temperature and pressure: In high-temperature and high-pressure conditions, select appropriate gasket and bolt materials to prevent leakage caused by thermal expansion and contraction or stress concentration.
• Corrosive media: For corrosive media, choose valves made of corrosion-resistant materials and implement corrosion prevention measures.

8. Environmental Requirements

• Protective measures: When installing in outdoor or corrosive environments, take protective measures for the valve, such as applying anticorrosive paint or installing protective covers.
• Temperature control: In extreme temperature environments, take insulation or cooling measures to prevent the valve from failing due to temperature effects.