The maintenance principles during valve operation are as follows:


① keep the outside and moving parts of the valve clean and protect the integrity of the valve paint. The surface of the valve, the trapezoidal thread on the valve stem and the valve stem nut, the sliding part of the valve stem nut and the bracket, and the gear, worm and other parts are easy to deposit many dirt such as dust, oil and media residue, which will cause wear and corrosion to the valve. Therefore, always keep the valve clean. The general dust on the valve can be brushed by brush and compressed air, or even brushed by copper wire until the metal luster appears on the processing surface and matching surface, and the paint surface shows the true color of the paint. The steam trap shall be in the charge of a specially assigned person, and shall be checked at least once per shift; the flush valve and the bottom plug of the steam trap shall be opened regularly for flushing, or removed and washed regularly to prevent the valve from being blocked by dirt.


② good lubrication conditions are required to keep the lubrication of valve, trapezoidal thread of valve, sliding part of stem nut and bracket, bearing position, meshing part of gear and worm gear as well as other matching and moving parts, so as to reduce mutual friction and avoid mutual wear. For the parts without oil cup or nozzle, which are easy to be damaged or lost in operation, the lubrication system shall be repaired and equipped, and the unblocking of oil circuit shall be verified.

The lubricating parts shall be oiled regularly according to the specific conditions. The frequently opened and high temperature valves are suitable for filling once every week to a month; the filling cycle of the valves not frequently opened and low temperature can be longer. Lubricants include oil, butter, molybdenum disulfide and graphite. Oil is not suitable for high temperature valves; butter is not suitable either, they will be lost due to high temperature melting. High temperature valve is suitable for adding molybdenum disulfide and wiping graphite powder. For the exposed lubricating parts, such as trapezoidal thread, tooth space, etc., if grease and other grease are used, it is easy to be contaminated with dust, while if molybdenum disulfide and graphite powder are used for lubrication, it is not easy to be contaminated with dust and the lubrication effect is better than that of butter. Graphite powder is not easy to be directly coated, and it can be used with a little oil or water mixed into paste.

The plug valve with oil filling seal shall be filled with oil according to the specified time, otherwise it is easy to wear and leak.


③ keep the two pieces complete and intact. The bolts of flange and bracket shall be complete and fully buckled, and no looseness is allowed. If the fastening nut on the hand wheel is loose, it shall be tightened in time to avoid wearing the connection or losing the hand wheel. After the handwheel is lost, it is not allowed to replace the handwheel with a movable plate, and it shall be equipped in time. The packing differential pressure shall not be skewed or without pre tightening clearance. For the environment easily polluted by rain, snow, dust and other pollutants, the valve rod shall be equipped with a protective cover. The scale on the valve shall be complete and accurate. The lead seal, cap and pneumatic accessories of the valve shall be complete and intact. The insulation jacket shall be free of dents and cracks.


In addition, it is not allowed to knock, support heavy objects or stand on the valve to avoid contaminating the valve and damaging the valve. Especially for non-metal mesh door and cast iron valve, it is more forbidden.


Maintain the daily maintenance of electric devices. Generally, the maintenance of electric devices shall not be less than once a month. The maintenance contents include: the surface shall be clean without dust accumulation, and the device shall not be contaminated by steam and oil; the sealing surface and points shall be firm and tight. There shall be no leakage; the lubricating part shall be oiled as required, and the valve nut shall be greased; the electrical part shall be in good condition, without phase failure, the automatic switch and thermal relay shall not trip, and the indicator light shall display correctly.