17
In
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Necessary devices
The following devices are needed to the metering pump. Be sure to install, or personal injury or property dam-
age may result.
■ Relief valve
The metering pump by nature keeps working, exceeding the limit pressure of discharge line if it is blocked. This
may damage the pump/piping system and burn out the motor. Install a relief valve close to the pump and fix its
set pressure below the maximum allowable pressure of the pump/discharge line.
■ Back pressure valve
Discharge line pressure must be 0.03MPa or higher than suction line pressure. Otherwise, check valve may
not check flow and overfeeding may result. Install a back pressure valve on the discharge line to keep the mini-
mum pressure difference as necessary.
■ Strainer
Provide a 40-mesh strainer at the end of a suction line and clean it periodically. Otherwise, clogging may
result.
■ Pressure gauge
Install a pressure gauge to monitor the discharge line pressure.
Overfeeding is the condition that check valves in the pump head stay open and liquid continues flowing
into discharge line. Always keep the discharge line pressure 0.03MPa or higher than a suction line pres-
sure.
Pipework
Glossary
