Daily meticulous maintenance of valves
The valve is mainly used to isolate equipment and pipeline system, regulate flow, prevent backflow, regulate and discharge pressure. It is a control element in the fluid pipeline system and plays a very important role. Therefore, attention should be paid to the maintenance of the valve during normal use. Now, let’s introduce the daily maintenance methods of valves.
1、 Daily maintenance of valves
1. The valve shall be stored in a dry and ventilated room and blocked at both ends of the passage.
2. The valve shall be inspected regularly, and the dirt on it shall be removed, and the anti rust oil shall be coated on its surface.
3. The valve after installation and application shall be regularly overhauled to ensure its normal operation.
4. Check whether the sealing surface of the valve is worn, and repair or replace it as appropriate.
5. Check the trapezoidal thread wear of the valve stem and valve stem nut, and check whether the packing is out of date and invalid, and replace it if necessary.
6. The sealing performance of the valve shall be tested to ensure its performance.
7. The valve in operation shall be intact, the bolts on the flange and bracket shall be complete, the threads shall be undamaged, and there shall be no looseness.
8. If the hand wheel is lost, it shall be provided in time, instead of being replaced by a monkey wrench.
9. The packing gland shall not be skewed or have no pre tightening clearance.
10. If the valve is used in a harsh environment and is easy to be contaminated by rain, snow, dust, wind and sand, a protective cover should be installed for the valve stem.
11. The ruler on the valve shall be complete, accurate and clear, and the valve shall be sealed and capped.
12. The insulation jacket shall be free from dents and cracks.
13. Avoid knocking or supporting heavy objects on the valve in operation.
2、 Maintenance during valve greasing
The professional maintenance of valves before and after welding plays a vital role in the production and operation of valves. Correct, orderly and effective maintenance will protect the valves, enable them to function normally and extend their service life. Valve maintenance seems simple, but it is not. There are often overlooked aspects of work.
First, the problem of the amount of grease injection is often ignored when the valve is filled with grease.
After the grease gun is refueled, the operator selects the valve and grease connection mode to conduct grease injection. There are two situations: on the one hand, the amount of grease injected is small and insufficient, and the sealing surface is accelerated to wear due to lack of lubricant. On the other hand, excessive grease injection causes waste. The reason is that the sealing capacity of different valves is not accurately calculated according to the valve type category. The sealing capacity can be calculated according to the size and category of the valve, and then a reasonable amount of lubricating grease can be injected.
Second, the pressure problem is often ignored when the valve is greased.
During the grease injection operation, the grease injection pressure regularly changes from peak to valley. The pressure is too low, the sealing leakage or failure pressure is too high, the grease injection port is blocked, the grease inside the seal is hardened, or the seal ring is locked with the valve ball and valve plate. Generally, when the grease injection pressure is too low, the injected grease flows into the bottom of the valve chamber, usually in small gate valves. If the grease injection pressure is too high, on the one hand, check the grease injection nozzle and replace it if the grease hole is blocked; On the other hand, it is necessary to use cleaning fluid to harden the failed sealing grease repeatedly and inject new lubricating grease for replacement. In addition, the seal model and seal material also affect the grease injection pressure. Different seal forms have different grease injection pressures. Generally, the grease injection pressure of hard seal is higher than that of soft seal.
W: www.winwinpipe.com
M: rosie.lu@winwinpipe.com
Post time: Dec-16-2022