Liquid Controls Optical Air Eliminator US Patent 7000628 Refined Fuels Applications A8981 & A8981A - Manual (Page 4)

4
Introduction
How the Optical Air Eliminator Works
A solenoid valve, located at the top of the air eliminator,
is either open or closed. When the liquid level is below
the optical sensor (Figure 1), and a delivery is initiated,
the solenoid valve opens and vents air and vapor to
atmospheric pressure. At the same time, a solenoid-actu-
ated control valve (A2982-11 or A2848-11) closes at the
meter outlet.
When liquid rises to the optical sensor level as the air is
exhausted (Figure 2), the optical air eliminator solenoid
valve closes and prevents continued venting to atmo-
spheric pressure. At the same instant, the control valve
at the meter outlet opens so that a delivery may begin or
continue. This functionality ensures that only liquid passes
through the meter for measurement.
As long as a delivery is active and the liquid level remains
at or above the optical sensor, the optical air eliminator
solenoid valve remains closed and the control valve re-
mains open. If the liquid level should drop below the optical
sensor, the optical air eliminator solenoid valve opens and
the control valve closes. When the delivery is complete,
the control valve closes and the printer prints a delivery
ticket. The optical air eliminator solenoid valve is not ac-
tive between deliveries and remains OFF or closed.
Figure 2: Liquid Level at or above Optical Sensor
Solenoid Valve - OPEN
Vent
Optical Sensor
Control Valve - OPEN
Liquid Level
Figure 1: Liquid Level below Optical Sensor
Solenoid Valve - OPEN
Vent
Optical Sensor
Control Valve - CLOSED
Liquid Level