What are common valve failure
Valve in the course will inevitably fail, common faults which have caused the fault, what does? Understanding of these troubleshooting great for us all to help. General common faults are:
A valve body and bonnet connection leak:
Its possible causes are: bolted flange connections caused by uneven sloping flange or fastening bolt tightening force is not enough, body and bonnet connection surface is damaged; gasket is damaged or does not meet the requirements; flange joint surface is not parallel to the flange machined surface is not good; stem bushing and valve stem of the valve cover bad thread processing is tilted.
(2) are not tightly closed gate:
The main reason this happens there: Close strength enough; debris falling between the valve seat and gate; valve sealing surface machining bad or damaged.
3. Sealing surface leakage:
Sealing surface leakage main reasons are: sealing surface damage, such as indentation, abrasion, middle break; adhesion between the sealing surface dirt poor or ring connection and so on.
4. Packing leak:
Packing leak causes are: filler plate without compression; filler is not enough; filler due to improper care and failure; stem or stem roundness exceeds the specified surface scratches, groove, brushed and rough defects; filler varieties, structure size or quality does not meet the requirements.
5 gate interfere with the valve cover:
When you open valve to fully open state, and sometimes can not be achieved gate wide open, and the emergence gate and valve cover interference. The reason is: gate valve cover is not installed correctly or the geometry does not meet the standard requirements.
6 stem rotation is not flexible or stuck:
Stem rotation is not flexible or stuck, and its two main reasons: packing too tight; stuffing into the stuffing box when irregularities; stem and stem bushing using the same materials or improper selection; stem and bushing the gap is not enough; stem to bend; threaded surface roughness substandard requirements.
7 other aspects:
Such as casting defects arising from trachoma, the sealing surface cracks, etc. will also affect the normal use of the valve, shall take appropriate measures to address them.