18
3.5
Auto Air Vent Valve Operation
The Auto Air Vent Valve is an option on select EW and EK pumps and replaces the standard
Manual Air Vent Valve when ordered. It is used primarily in applications where gassing is a
problem and pumps can lose prime.
Unlike the Manual Air Vent Valve, the Auto Air Vent Valve constantly bleeds a controlled
amount of volume out of the “Air” vent. Therefore, the “Air” vent should
always
be plumbed
back to the source tank. During priming, the access knob does not have to be loosened as with a
manual air vent valve as pressure is relieved through the vent. The Top Valve Guide assembly
uses a bottom seat to ensure that air is not introduced into the discharge media and utilizes a
precisely machined top seat that allows air to be quickly purged but limits the amount of liquid
returned to the tank. A sleeve valve is used to maintain backpressure within the pump head,
which helps speed the purging of air.
3.6
Priming
Install the pump as described in Section 2.0. With the pump turned on, set stroke length at
100% and frequency to 360 SPM. If the pump is equipped with an air vent valve, open the knob
1/2 turn. Liquid should move up through the suction tubing and into the pump head. When
liquid starts running through the vent side tubing, close the air vent knob and continue with
output adjustment described below. If the pump has no air vent valve, disconnect the discharge
tubing from the injection valve. When liquid enters the discharge tubing at the pump head, stop
the pump. Then reconnect the discharge tubing to the injection valve.
If the pump does not self prime, remove the check valve housing on discharge & suction sides to
make sure valve cartridges and gaskets are in correct positions (see section 4.2 for correct
orientation).
Note:
Pumps with FC liquid ends may need assistance if dry priming due to the hard valve seat
material.
AAVV – Cross Sectional
View
Discharge to Process
Sleeve
Valve
Suction
Gas Vent
Top Check Ball
and Seats
Access Knob
