VACUVENT VA Series, Owner'S Manual

Page: 15 / 18

Independent Valve Marketing (Pty) Ltd
Engineering Page 15 of 18
VSS0203WD00
Figure 5- Pumped Example for Air Valve Placement
SIZING
Most sizing is based on the need to protect the pipeline from a negative pressure, vent the initial air,
and to vent the pressurised air with the importance generally in that order. A good start is to select
a scouring or drainage rate based on rupture or draining of 2-3 times the designed flow rate of that
particular section. Size the air release valves to protect the pipeline and seals from low pressure
within the pipeline during draining or other pipeline disturbances (e.g. pump trip).
One accepted method is to limit the internal pressure to 3.5 m
∆P (5 Psi) below atmospheric
pressure. The air release valves curves in each individual valve catalogue indicate that point and
the resultant inflow of air.
GENERAL OPERATION
The Vacuvent series air release valves provide a full bore solution to any pipeline. The large orifice
is not restricted in vacuum and during filling operation works through the anti-shock nozzle only.
Vacuvent air valves operate in reaction to the pipeline conditions and require no external input from
the end user.