Dikkan DN400 Manuale di istruzioni per l'uso - Pagina 13

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9. OPERATION

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Globe valves are operated manually by handwheel. The handwheels are designed such that reasonable effort

exerted by the operators is sufficient to operate the valve. All Dikkan globe valves have open and closed marked

on the hand wheels along with directional arrow. To open, turn the handle in a counterclockwise direction. To

close, turn the handle in a clockwise direction. Whenever possible, open and close the valve slowly. This is

particularly important in piping systems containing liquids where quick valve closure (with other factors) could

lead to the possibility of an undesirable pressure surge (water hammer) in the piping system.

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Level indicator models, you can follow the valve open- close rates on the level indicator.

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If the hand wheel is difficult to turn, loosen packing nut ¼ to ½ turn. Retighten packing nut after open-close

operation is completed.

Valves with balancing plugs have to be installed with medium flowing over the plug (a) as indicated by flow direction

arrow on valve body. When the valve is closed, anticlockwise rotation of the hand wheel lifts the pilot plug (b) off the

larger balancing plug (a). This allows the medium to pass through the plug and equalizes the pressure of the medium

under the plug (a). After the pressures have been equalized within the values stated, the valve can be opened by turning

the valve further with normal manual force.

Doc. No: FRM.65

Rev. No: 00 Rev. Date: 01.06.2015