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4 Sediment discharge function 4.1 Function description
The sediment discharge takes place through a number of
ports (3) in the bowl wall. Between discharges these ports
are closed by the sliding bowl bottom (1), which constitutes
an internal bottom in the separating space. The sliding bowl
bottom is held against a seal ring (4) by the water acting on
its underside. The pressure is produced during the rotation
because of the centrifugal force and increases with the
distance from the axis of rotation of the bowl. The operating
water exerts an upward pressure exceeding the counter-
acting downward pressure from the process liquid because
the underside of the sliding bowl bottom has a larger
pressure surface than its upper side.
The space below the sliding bowl bottom is kept closed by
valve plugs (6) seated in an operating slide (2). This slide is
forced upwards by coil springs (7). A constant water level is
held in the operating water chamber (8) by means of a
paring disc (12).
When a discharge shall be effected, compressed air forces
the piston in the OWMC forwards. Water is now supplied in
such quantity that water flows over the edge of operating
water chamber and onwards through the channel (9) to the
upper side of the operating slide.
• The slide is forced downwards by the liquid pressure
created between the operating slide and the bowl body
thereby opening the valve plugs enabling the closing
water under the sliding bowl bottom to escape.
• The sliding bowl bottom is pressed downwards,
uncovering the ports in the bowl wall so that the
sediment is discharged.
• The water on the upper side of the operating slide is
drained off through a nozzle (10).
• When water has been sufficiently drained through the
nozzle, the coil springs again force the operating slide
upwards, closing the valve plugs. The sliding bowl
bottom is forced upwards by the operating water supply.
Thus the bowl is closed.
• The low pressure water is supplied during the whole
cycle.
• The operating water now presses the OWMC piston
back into its end position by means of the operating
water pressure. The discharge is completed.
Solids and / or excessive mineral content in the operating
water will disturb, and eventually block the discharge
function.
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