Due to the presence of pores with water valve castings, slag, cracks, shrinkage and osteoporosis, a large number of weaknesses in the operation of the valve will be exposed at any time, become a hidden threat to safe operation.
1, with the water valve seal leakage can result in substantial damage to the system media. The valve stem seal leakage is generally not timely compaction caused by loose bolt filler plate, in the event often leads to a major accident. Another reason is because the stem surface treatment processes or materials are medium corrosion or improper selection packing corrosion failure of the stem seal surfaces.
2, with the water valve stem rust at the top and bottom surfaces of the Games bring out its filler particles filling the gap appears repeatedly breach, such as improper maintenance, high-pressure or high-speed media in a very short period of time filling out the form leak .
3. Similarly, stainless steel wire wound graphite materials for high pressure seal self-tight seal valves and stainless steel with graphite spiral wound gasket in the flange sealing valves should prevent the occurrence of such situations. Another reason often cause a lot of leakage of the medium, namely with the gap between the gland and the stem is too large, with a water valve stem up and down movement, the gap is too large due to repeated friction filling out the window dressing, eventually filling pressure tighter than the pressure drop, resulting in leakage.
Water distribution valve is sealed by force, that is, when the valve is closed, to rely on external pressure to force the gate valve to ensure the tightness of the sealing surface. The reason is that it is exposed above, we read it later in use, to avoid the problems exposed.