The Plunger Pump System
The difference between the plunger and the piston pump system is that the plunger system does not require any close tolerance parts such as cylinders or precise piston seals, etc. The plunger is sealed by a simple maintenance-free seal. Plungers with various diameters can be mounted on the ZMP 700 series of pumps. This grants the highest possible pressure and output ranges flexibility for each individual model.

Automatic Pressure Control (APC)
The ZMP 700 pumps are equipped with control valves which allow precise pre-setting of the maximum grout pressure. When the pre-set pressure is reached, the pump delivers only as much grout as the injection point will take at the pre-set pressure. If there is no more grout take, the pump automatically stops and maintains the pressure for any time period. Low pressures of only 1 bar can be pre-set on some models. The APC system guarantees safe grouting of delicate formations without risking hazardous overpressure.

Flow Control
The built-in flow control permits the setting of a maximum flow rate. With this feature, slow penetration of soft ground can be achieved without risking segregation of the grout or creating new voids. The flow control together with the APC pressure control system allows the use of these pumps for permeability tests.

Valves
The grout valves are made of high grade alloy steel for long life. The valve seats are reversible. The special design of the hydraulic system provides for a high speed suction stroke of the plunger, which creates a relatively high grout velocity in the suction valves. Thus, heavy particles will be flushed away and the valves are kept clear. The design of the valves allows pumping of grouts with low water/cement ratios or sanded grouts with a particle size of up to 8 mm.

Maintenance
In the design of these pumps, Häny has paid great attention to simple maintenance and easy cleaning. The suction and discharge valves can be dismantled quickly. The plunger seal consists of maintenance free, wear resistant seal rings.

Modular Pump System
The pumps of the ZMP 700 series are designed as an interchangeable modular system. The pump modules are identical on both single and double acting units. Thus wear and spare parts are also identical throughout the entire line which simplifies the stocking of spare parts.