Metering Pumps _ High Suction Head and High Vacuum in Delivery Line

There was installations where the suction head is  higher than delivery head and
or delivery line under high vacuum

This causing syphoning , and flowrate will not be be accurrate , often very much higher than
set at the Metering pump .

Solution
a) Installing a back Pressure Valve
b) pressure loading valve
or
c) Installing a Pressure relief valve to the Pipeline or vessel under high vacuum

This (c) is the simplest cost effective solution