Introduction
The following instructions provide information on the installation, operation and maintenance of ACCU-
VENT, automatic degassing valves, manufactured by Primary Fluid Systems Inc. The valves are
designed to improve the performance and safe operation of most pumps used for metering
applications.
The standard valve assembly is constructed of CPVC (Corzan) wetted parts, for use specifically with
Sodium Hypochlorite, Sulfuric Acid to 98% and Hydrogen Peroxide to 30%. Alternative material options
include 316L Stainless Steel and PVDF.
The automatic degassing valve is rated to a maximum working pressure of 150 PSIG.
Special Features of the ACCU-VENT Assembly:
•CPVC corrosion resistant wetted materials of construction
•Special material designed float automatically vents built up gases on system start-up and under
working pressure
•Can be used on feed side or discharge side of pump (or both)
•Std. 1/2" NPT threaded connections or optional ¼”, ¾”, and 1” NPT connection, including socketweld
and BSPT
•Available in other materials of construction for various gaseous liquid chemicals
Automatic Degassing Valve:
Our standard automatic degassing valves are designed to automatically vent gases and vapors that are
commonly released from Sodium Hypochlorite or Hydrogen Peroxide. Gases or vapor are
compressible, and if not vented cause what is known as vapor lock in your metering pump and the
system, causing the metering pump to malfunction and in most cases cause the pump to stop
discharging chemical to the system.
The valve is designed to allow for the venting of gases and condensed vapor back to the feed tank,
which improves priming on initial start-ups and continuous trouble free operation while working under
pressure.
The valve when in operation vents gases, vapor and a small amount of liquid, which is the same as the
chemical being pumped. This discharge must be returned through hard piping or tubing back to tank, to
prevent personnel or equipment from coming in contact with vented corrosive fluid.
Caution:
It is recommended that the automatic vent discharge be piped back to tank through the
use of hard pipe or tubing. Failure to do so could result in hazardous consequences.
(see typical installation)
Automatic Degassing Valves: Reason for Selection and Use
Metering pumps handling chemicals such as Sodium Hypochlorite or Hydrogen Peroxide, will always
be subject to the problem of venting off a build up of gases inherent to these chemicals. Some metering
pumps are available with a built in degassing valve, but these are either a manual arrangement
requiring constant monitoring and physical adjustment, or based on a constant bypass through a fixed
orifice, which reduces pump discharge and efficiency. Our automatic degassing valve vents off any
build up of gases through the use of a special float mechanism, which senses the gas and opens the
discharge vent allowing the gas and vapor to escape back to tank. When the float senses liquid, the
valve automatically closes the discharge port, blocking liquid from venting back to tank.
