Inspection and Installation of valves
1. Make sure the model number and specification meet the requirements of drawings.
2. Make sure the stem and disc can rotate easily, no sense of blocking and deflection.
3. Make sure the valve is in good condition and no damage; keep the thread end completed and proper.
4. Check up if the seat and body are welded firmly and the tie between disc and seat; bonnet and body; stem and disc.
5. Check up if the gasket, packing and fasteners are suitable for the working conditions.
6. For the long-stored pressure-relieving valve, need to check the dust and sand.
7. Remove the covers and check up the seal performance, making sure the disc can close to the seat.
All valves should do the shell and seal test.
Shell testing is performed when valve opens, with 1.5 times of the nominal pressure. Check up the leakage of the valve body. Test time should be more than 5 min. Body and packing gland should not leakage.
Fully close the valve and do the seal test. Check if there is leakage from the seal surface. Testing pressure equals to the nominal pressure. No leakage is allowable.