The maintenance principles during valve operation are as follows:
① Keep the exterior and moving parts of the valve clean, and protect the integrity of the valve paint. The surface of the valve, the trapezoidal threads on the valve stem and valve stem nut, the sliding parts of the valve stem nut and bracket, as well as components such as gears, worm gears, etc., are prone to depositing a lot of dust, oil stains, and media residue, which can cause wear and corrosion to the valve. Therefore, valves should be kept clean regularly. Generally, dust on valves can be brushed with a brush or compressed air, and even brushed with a copper wire brush until the machining surface and mating surface show a metallic luster, and the paint surface shows its true color. Steam trap valves should be inspected by a dedicated person at least once per shift; Regularly open the flushing valve and steam drain valve bottom plug for flushing, or dismantle them regularly for flushing to prevent dirt from blocking the valve.
② Good lubrication conditions are required to maintain the lubrication of the valve, the trapezoidal threads of the valve, the sliding parts of the valve stem nut and bracket, the meshing parts of the bearing position, gears and worm gear, and other mating moving parts, in order to reduce friction and avoid mutual wear. For parts without oil cups or nozzles that are prone to damage or loss during operation, the lubrication system should be repaired and equipped, and the oil circuit should be verified for smoothness.
Lubricating parts should be lubricated regularly according to specific situations. Valves that are frequently opened and have high temperatures are suitable for refueling at intervals of one week to one month; Valves that are not frequently opened and have low temperatures can have a longer refueling cycle. Lubricants include engine oil, butter, molybdenum disulfide, and graphite. Engine oil is not suitable for hightemperature valves; Butter is also not very suitable as it will melt at high temperatures and be lost. High temperature valves are suitable for adding molybdenum disulfide and wiping graphite powder. Lubricating parts exposed to the outside, such as trapezoidal threads, interdental areas, etc., are easily contaminated with dust if butter or other grease is used. However, lubricating with molybdenum disulfide and graphite powder is less likely to be contaminated with dust and has a better lubrication effect than butter. Graphite powder is not easy to apply directly, and a small amount of oil or water can be mixed into a paste to use.
The oil sealed plug valve should be filled with oil at the specified time, otherwise it is prone to wear and leakage.
③ Keep both items complete and intact. The bolts of the flange and bracket should be complete and fully fastened, and no looseness is allowed. If the fastening nut on the handwheel is loose, it should be tightened in a timely manner to avoid wear on the connection or loss of the handwheel. After the handwheel is lost, it is not allowed to replace it with a trapdoor, and it should be prepared in a timely manner. The pressure difference of the packing should not be skewed or have no pre tightening clearance. In environments that are prone to pollution from rain, snow, dust, and other pollutants, protective covers should be installed on the valve stem. The scale on the valve should be kept intact and accurate. The lead seal, cap, pneumatic accessories, etc. of the valve should be complete and intact. The insulation jacket should have no dents or cracks.
In addition, it is not allowed to knock, support heavy objects or stand on the valve to avoid dirtying or damaging the valve. Especially non-metallic mesh doors and cast iron valves should be avoided.
Maintain daily maintenance of electric devices. The maintenance of electric devices is generally not less than once a month. The maintenance content includes: the appearance should be clean, without dust accumulation, and the device should not be contaminated with soda or oil; The sealing surface and points should be firm and tight. No leakage phenomenon; Lubricating parts should be lubricated according to regulations, and valve nuts should be lubricated with grease; The electrical part should be intact, without any phase faults, the automatic switch and thermal relay should not trip, and the indicator light should display correctly.