Dikkan DN150 Інструкція з експлуатації Посібник з експлуатації - Сторінка 10

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8. MAINTENANCE

Dikkan globe valves are designed to have minimum maintenance. But if you carry out the following maintenance, they

will increase the longevity and reliability of the valve.

Valves shall be dismounted from pipe line before maintenance and shall be cleaned from medium.

Maintenance work must be performed by qualified, trained and skilled people according to

maintenance instructions Welding is not accepted on valves repairing.

•

In very seldom used places, valves should be performed open-close every 3-4 months.

•

The stem threads that are exposed to atmosphere should be periodically lubricated, with quality grease.

•

Bonnet bolt tension should be checked periodically when valves are used in high temperature applications

where loosening may occur. Although leaks through ring joints are rare, erosion or corrosion could cause rings

to fail. In these cases, a new ring gasket is required.

•

The valve gland packing should be inspected at least monthly. If the gland packing shows signs of leakage,

simply tighten the adjusting nuts (P.No15) to compress the packing. Do not over-tighten the adjusting nuts as

this will make operation of the valve more difficult. If, after tightening the adjusting nuts to their fullest extent, the

leakage does not stop, it is then necessary to replace the gland packing.

At any circumstances, packing replacement is dangerous and not recommended for the valves

under pressure. Even the valve is back seated; it is not possible to make sure that any particle is avoiding

backseat to be at full closed position.

Backseat function shall only be used for avoiding or minimizing leakage of medium left in the line after

shutting down the line and taking away the line pressure. Rather than attempting to repack under pressure, it

is preferable to use the backseat to control the stem leakage until a shutdown provides safe repacking

conditions.

Valves shall not be retained fully back seated during usage. This may yield packing to dry and cause

the valve leakage. After the valve has been opened fully, rotate the hand wheel quarter turn towards the close

position.

Unscrew nuts (P.No15) and raise gland (P.No12). Remove all of the old gland packing with packing hook. Clean the

stuffing box and stem.

Doc. No: FRM.65

Rev. No: 00 Rev. Date: 01.06.2015