How to maintain pipeline valves in use,The purpose of maintenance during the operation of pipeline valves is to ensure that the valves are in a state of perennial cleanliness, good lubrication, complete valves and normal operation.
cleaning of valves
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 support, and the gear, worm gear and other parts are easy to be stained with dirt such as dust, oil stain and medium residue, which will cause wear and corrosion to the valve. Therefore, it is very important to keep the exterior and moving parts of the valve clean and protect the integrity of the valve paint. The dust on the valve is suitable for brush brushing and compressed air blowing; The dirt between the trapezoidal thread and the teeth is suitable for wiping with a rag; The oil stain and medium residue on the valve are suitable for steam purging, or even brushing with copper wire until the processing surface and mating surface show metallic luster, and the paint surface shows the natural color of paint. The drain valve shall be in the charge of a specially assigned person, and shall be inspected at least once per shift. The flushing valve and the plug at the bottom of the drain valve shall be opened regularly for flushing, or the drain valve shall be disassembled and flushed regularly to avoid clogging the valve with dirt.
lubrication of valves
The trapezoidal thread of the valve, the sliding part of the valve stem nut and the support, the bearing part, the meshing part of the gear and worm wheel and worm, and other mating parts need good lubrication conditions to reduce friction and avoid mutual wear. Some parts are specially equipped with oil cups or nozzles. If they are damaged or lost during operation, they should be repaired and equipped, and the oil path should be unblocked.
Lubricating parts shall be regularly oiled according to specific conditions. Frequently open valves with high temperature are suitable for refueling once a week to a month; The refueling cycle of valves that are not frequently opened and have low temperature can be longer. Lubricants include engine oil, butter, molybdenum disulfide and graphite. High temperature valves are not suitable for oil and butter, which will be lost due to high temperature melting. Instead, they are suitable for injection of molybdenum disulfide and graphite powder and for exposed parts requiring lubrication. For example, if grease such as butter is used for trapezoidal thread and gear, it is easy to get dust, while molybdenum disulfide and graphite powder are used for lubrication, it is not easy to get dust, and the lubrication effect is better than butter. Graphite powder is not easy to apply directly. It can be mixed with a little oil or water to form a paste.
The plug valve for oil filling seal shall be filled with oil at the specified time, otherwise it is easy to wear and leak.
Valves in operation and various valves shall be complete and intact. The bolts on the flange and bracket are indispensable, and the threads shall be intact without looseness. The fastening nut on the hand wheel shall be tightened in time if it is found to be loose, so as to avoid abrasion of the connection or loss of the hand wheel and nameplate. If the hand wheel is lost, it is not allowed to replace it with a spanner, and it should be equipped in time. The packing gland shall not be skewed or have no pre tightening clearance. For the valve in the environment easily contaminated by rain, snow, dust, wind and sand, the valve stem shall be installed with a protective cover. The scale on the valve shall be complete, accurate and clear. The lead seal, cap and pneumatic accessories of the valve shall be complete and intact. The insulation jacket shall be free of depression and crack. It is not allowed to knock, stand or support heavy objects on the valves in operation; Especially non-metallic valves and cast iron valves