The operation of the cut-off valve, a variety of valve parts should be complete, intact. The bolts on the flange and the bracket are indispensable, the thread should be intact, and the loosening phenomenon is not allowed. The fastening nut on the handwheel, if found loose should be tightened in time, lest wear connection place or lose Handwheel and nameplate. If the handwheel of the globe valve is lost, it is not allowed to be replaced with a live wrench. Padding gland does not allow skew or no pretension clearance. For the easy to be affected by rain and snow, dust, sand and other pollutants in the environment of the cut-off valve, the valve stem to install protective cover. The ruler on the cut-off valve should be kept intact, accurate and clear. Cut-off valve seals, caps, pneumatic accessories should be complete intact.
Not allowed to knock on a running stop valve, the station person or supports the load-bearing material, specially the nonmetal valve and the cast iron valve, must prohibit the valve to grease the maintenance work before the welding before putting into operation and after putting into operation the valve specialized maintenance work, for the valve serves in the production operation to play the vital role, Correct and orderly and effective maintenance will protect the valve, so that the valve functions properly and extend the service life of the valve. Valve maintenance work seems simple, it is not. Often overlooked aspects of work.
First, the cut-off valve when injecting grease, often ignore the problem of fat injection. After filling the grease, the operator selects the valve and the grease coupling way, carries on the grease-filling work. There are two kinds of situations: on the one hand, the amount of fat less grease, sealing surface due to lack of lubricant and speed up wear. On the other hand, excessive injection of fat, resulting in waste. is not based on the valve type category, the different cut-off valve sealing capacity for accurate calculation. The sealing capacity can be calculated by the cut-off valve size and category, and the appropriate amount of grease is injected.
Second, when the cut-off valve grease, often ignore the pressure problem. In the operation of grease injection, the pressure of Grease is regularly changed in peak and valley. Pressure is too low, sealing leakage or failure, pressure is too high, grease mouth plug, sealed internal lipid hardening or sealing ring and valve ball, valve board to die. Usually, when grease pressure is too low, the injected grease goes into the bottom of the valve cavity, usually in a small gate valve. and fat injection pressure is too high, on the one hand, check the fat hole, such as lipid blocking to determine the situation to replace; On the other hand is lipid hardening, to use cleaning fluid, repeatedly soften the failure of the sealing grease, and inject new grease replacement. In addition, sealing type and sealing material, also affect the injection pressure, different sealing forms have different pressure, the general situation of hard sealing grease pressure is higher than the soft seal. Ball valve maintenance is generally in the open position, under special circumstances choose to close maintenance. Other valves are not punishable by open position. Gate valve in the maintenance must be in a closed state, to ensure that grease along the seal ring filled with sealing groove, if open, sealing grease directly off the inlet or valve cavity, resulting in waste.
After installation, the cut-off valve should be inspected regularly, and the main items are inspected:
(1) The seal surface wear of the cut-off valve.
(2) The wear of trapezoidal thread of stem and stem nut.
(3) Whether the filler is obsolete or not, if the damage should be replaced in time.
(4) The sealing performance test shall be carried out after overhaul and assembly of the cut-off valve.