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avoid solid particles or welding splinters which may be harmful for sealing surfaces,
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strainer ( wire mesh filter) installed before the valve increases certainty of its correct action.
6.
MAINTENANCE
During maintenance following rules should be observed:
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startup process – sudden changes of pressure and temperature should be avoided when starting the plant,
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valve is closed by turning the handwheel clockwise when looking from above the handwheel (according to arrow
direction marked on the handwheel),
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valve is opened by turning the handwheel counter-clockwise,
It is prohibited to use additional lever when turning the handwheel
,
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performance of fitted valves can be checked by multiple closing and opening,
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if leakage on stem occurs for valves Fig.215, 216 (PN6 – PN25) it is necessary to tighten with moderate force two T-bolt
nuts pressing the packing gland until the leakage disappear, for SDNR valves Fig.215, Fig.216 (PN40) similar nuts on eye
bolts, whereas for stop valves Fig.215 (PN40) packing rings are pressed by tightening threaded gland nut screwed in the
bonnet, the nut press the rings by gland,
-
in the case of necessity to replace packing rings, it should be done without overpressure inside the valve, when the valve is
completely open. In this position inner space of the valve is entirely shut off : stop valves are provided with back seat on
the upper part of disc which adheres to bonnet seat, SDNR valves are provided with flange on the stem which adheres to
bonnet seat,
-
in order to refill packing rings of valves Fig.215 i 216 (PN6 – PN25) unscrew the nuts on T-bolts, move the gland into
handwheel direction, working under lifted gland refill cut - packing rings in the stuffing box, then press again these cut
packing rings. There are similar procedures for SDNR valves Fig.215 , Fig.216 (PN40) but there are eye bolts instead of
T-bolts that can be swing aside. For stop valves Fig.215 (PN40) packing can be refilled when gland nut is unscrewed.
open
shut off
Tighten the nuts
