EBARA EFQT3 - Manual (Page 11)

EBARA Fluid Handling 11
AUTOMATIC AIR RELEASE VALVE
When properly installed and correctly
adjusted to the specific hydraulic operating
conditions of the application, the EBARA
Automatic Air Release Valve will permit air
to escape through the bypass line, and then
close automatically when the pump is fully
primed and pumping at full capacity.
Theory of Operation
Figures 3 and 4 show a cross-sectional view
of the Automatic Air Release Valve, and a
corresponding description of operation.
Figure 3 – Valve in Open Position
During the priming cycle, air from the pump
casing flows through the bypass line, and
passes through the Air Release valve to the
wet well (Figure 3).
Figure 4 – Valve in Closed Position
When the pump is fully primed, pressure
resulting from flow against the valve
diaphragm compresses the spring and
closes the valve (Figure 4). The valve will
remain closed, reducing the bypass of liquid
to 1 to 5 gallons (3.8 to 19 liters) per minute,
until the pump loses it’s prime or stops.
Some leakage (1 to 5 gallons [3.8 to 19
liters] per minute) will occur when the
valve is fully closed. Be sure the bypass
line is directed back to the wet well or
tank to prevent hazardous spills.
When the pump shuts down, the spring
returns the diaphragm to its original position.
Any solids that may have accumulated in the
diaphragm chamber settle to the bottom and
are flushed out during the next priming cycle.
NOTE
The valve will remain open if the pump
does not reach its designed capacity or
head. Valve closing pressure is
dependent upon the discharge head of
the pump at full capacity. The range of
the valve closing pressure is established
by the tension rate of the spring as
ordered from the factory. Valve closing
pressure can be further adjusted to the
exact system requirements by moving
the spring retaining pin up or down the
plunger rod to increase or decrease
tension on the spring. Contact your
EBARA distributor or EBARA for
information about an Automatic Air
Release Valve for your specific
application.
Air Release Valve installation
The Automatic Air Release Valve must be
independently mounted in a horizontal
position and connected to the discharge line
of the self-priming centrifugal pump (see
Figure 5).
NOTE
If the Air Release Valve is to be installed
on a staged pump application, contact
the factory for specific installation
instructions.
WARNING!