9.1.1 Automatic venting
The automatic venting facility (standard features on DE/DX 03, 07 otherwise optional extra) consists of a
non-return ball valve. The ball
③
rolls against the seat during the suction stroke and away from it during the
pressure stroke. The stroke length of the ball is determined by the screw
②
. Starting from the position at
which the screw blocks the ball, turn the screw by half a turn to the left and start the dosing pump. Depend-
ing on the
operating pressure that may already be applied at the discharge valve
③
, the dosing pump is primed until
until the metered medium emerges from the vent outlet
⑤
. Now tighten screw
②
until medium no longer
emerges and the dosing pump assumes normal delivery.
To regularly dispose of gas collected in the dosing head, a certain permanent, unavoidable leakage quantity
is to be established (approx. 25 - 30% of the dosing rate, corresponding to approx. 0.5 - 0.7 l/h on the
DE/DX 2) which flows through the vent outlet
⑤
via a 4/6 PVC hose back to the supply tank. The leakage
quantity is set by carefully turning screw
②
and locking nut
④
.
The leakage quantity depends on the operating pressure. If the operating pressure is subject to fluctuations,
the consistency of the leakage quantity and therefore of dosing itself can be increased by installing a pres-
sure control valve. The pressure control valve should be set approx. 0.5 bar above the maximum expected
operating pressure.
⑤
④
③
②
①
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| Operation & Maintenance Instructions | Start-up
