EBARA EFQU4 - Manual (Page 11)

EBARA Fluid Handling 10
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 its prime or stops.
WARNING!
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 Fluid Handling 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.
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).