A fluid metering or pumping device includes multiple pumping or metering elements that are connected so that they all operate together, moving in the same direction and at the same speed. The multiple pumping or metering elements are intended for use at high pressures where the strain from the pressure might distort the walls of the elements, and interfere with their pumping or metering accuracy. These elements are enclosed in, but preferably not directly connected to a pressure vessel that would contain the high operating pressure, leaving the pumping or metering element housings to only contain the pressure rise or fall that occurs within that element. The pumping or metering elements are connected to a support structure that also penetrates the pressure vessel, and contains an outlet port for that element. The pressure vessel connects the elements, and serves as an intake plenum for all of the elements.