Piston pumps are used when high pressures are to be generated. The flow rate of piston pumps is independent of the head and is determined only by speed. Its good suction performance is outstanding. Piston pumps belong to the group of positive displacement pumps. They transport the medium by a reciprocating motion of a piston in the pump working space, called stroke. The stroke creates a suction respectively vacuum effect used to deliver the water. The pulsating pressure curve of the pump can be damped with the aid of the air vessel. Flow rate and head are adjusted via needle valve and overflow valve. The experimental unit is fitted with sensors for pressure and flow rate. The cycle that takes place (intake and discharge of water) can be shown clearly in the p-V diagram. The position of the piston rod is measured by an angle sensor. This allows the determination of the cylinder volume. One pressure sensor measures the pressure at the outlet of the pump, another one measures the pressure in the inside of the cylinder.
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