User guide

6
7. Description and Operation
7.1 Principle of Operation
Reciprocating metering pumps are used with a wide variety of chemicals, such as sodium hypochlorite, that
produce gas within the piping and pump systems. This gas can accumulate in the pump reagent head,
causing the pump to “air bind” and lose prime.
The Automatic Valve Assembly (AVA) prevents this by allowing a small amount of pressurized fluid from
the discharge line to bleed back into the pump head, thereby helping to keep the pump head primed and
also displacing gas through the discharge check valve. The system also has a Manual Override Button to
enable faster pump priming at pump startup or other situations.
7.2 General Description
The PULSAR
®
and PULSAR Shadow
®
HypoPump
®
system consists of the pump reagent head, suction and
discharge valves, and Automatic Valve Assembly (AVA). The AVA consists of a pressure balanced valve
which opens periodically to allow fluid from the discharge line to bypass the discharge check valve and
flow back into the pump head. The valve is actuated by a solenoid controlled by a solid-state timer. This
pre-set timer will operate properly in the majority of HypoPump applications.
Power supply required is 115 or 230 VAC, 50 or 60 hz. All electrical components are enclosed in a NEMA
4X (IP 65) enclosure, which is isolated from the pumped fluid. The timer is preset at the factory to open for
0.25 second every 30 seconds in order to achieve optimum gas handling time with minimal pump capacity
loss. The valve assembly is easily removed from the pump head in order to access the discharge check
valve for cleaning or replacement. The automatic valve assembly can be run independently of the pump
motor and/or controls.
7.3 Operation of Manual Override Button
The Manual Override Button functions as a fast priming aid. For best results press the button down for 1
second every few seconds. Do not hold the button down continuously.
Figure 4