8
IOM
3.
OPERATION
The Air & Vacuum component, with the large orifice, discharges air at high flow rates during the filling of the
system, and admits air into the system, at high flow rates, during system’s drainage and at water column
separation. High velocity air does not blow the float shut. Water lifts the float which seals the valve.
At any time during system operation, if the internal pressure of the system falls below the atmospheric
pressure, air enters the system.
The smooth discharge of air reduces pressure surges and other destructive phenomena.
The intake of air in response to negative pressure protects the system from destructive vacuum conditions,
and prevents damage caused by water column separation. Air entry is essential to efficiently drain the system.
As the system starts to fill, the valve functions according to the following stages:
1.
Air in the pipeline is discharged by the air valve.
2.
Liquid enters the valve, lifting the float to its sealing position.
When the internal pressure falls below the atmospheric pressure (negative pressure):
1.
The floats drop down, immediately opening the Air & Vacuum orifices.
2.
Air enters the system.