Features / Benefits

• capacities up to 5 m3/h
• pressures up to 45 bar
• high viscosities up to 50.000 cP (mPas)
• moderate to high abrasiveness
• mild corrosiveness
• up to 15mm particle size
• up to 85% solids content

Where slurry consistency and particle size are beyond the limit of  handling capability of a crankshaft driven pump, consideration is given to hydraulic driven piston pumps. These are two cylinder, single-acting pumps with continuous water flush on the backside of the piston. These pumps are designed with a prerequisite low stroke rate, a low piston velocity and large flow areas, which also help to minimise wear. Cartridge mounted sensors are provided at either end of the hydraulic drive cylinders. Signals from opposed sensors/pistons enable a plc controlled stroke reversal and either piston to complete a full stroke. This method of leakage compensation enables the use of standard hydraulic piston seals, which afford a 5 to 100% capacity adjustment range. Larger size pumps use a linear transducer in lieu of sensors. lt reduces the length and weight of the piston and cylinder and enables a full stroke length independent of the stroke rate. The drive cylinder design, oil hydraulic flow sheet and plc programming aim to obtain a relatively smooth piston reversal and reduce hydraulically and mechanically induced loads. The larger size pumps accomplish piston pump stroke reversal by reversing the swash plate angle of the main oil pump(s) in lieu of manipulating a control valve. A detailed review of the slurry consistency, performance indicators and project requirements determines the choice for either of the two available piston pump models.

SHC - Piston pump with actuator assisted valves
The model SHC piston pump is fitted with large diameter, high lift, actuator assisted suction and discharge valves and handles rather viscous pastes and particles typically not larger than 15 mm. It uses the valve design from the diaphragm pump, except that the valve cone bolts directly onto the actuator rod. The actuator load and activation sequence is arranged such that a valve will not open against the pump discharge pressure. As a result the system is inherently protected against backflow, even if a valve is jammed open.