Piston Pump Machines

Optimum design of metering systems and equipment calls for detailed knowledge of the materials to be processed. Viscosity, abrasiveness, thixotropy, processing temperature, reactivity and reaction rate are all factors which influence the optimum process technology, and thus the design of the system – from the individual seals within a pump system to the configuration of the whole gluing or sealing machine.

If adhesives or sealants need to be mixed or dispensed, our systems are usually equipped with drum pumps. For medium to high-viscosity substances, we mostly use drum pumps based on scoop piston pump technology.

Suitable for low or high-viscosity substances

In our scoop piston pumps, the outlet valve is located in the piston itself. The material to be pumped is transported to the other side of the piston during the expulsion stroke and then ejected in the subsequent induction stroke, while new material is simultaneously drawn in on the other side of the piston. This enables our scoop piston pumps to achieve a delivery rate of approx. 98 cm³ per double stroke, at a maximum material pressure (system-dependent) of approx. 360 bar.

In order to pump highly viscous media (pasty) media, for instance from 20 l or 200 l drums, the scoop piston pump is mounted on what is known as a follower plate using a special device (which is why they are often referred to as follower plate pumps). The follower plate presses down on the pasty substance in the drum, thus pressing it through a hole to the pump’s intake manifold. The outer ring of the follower plate has a sealing lip, which presses against the inner wall of the drum and prevents air from being sucked or drawn in.

The follower plate is not needed for low-viscosity media (liquids). Here the suction pipe of the pump is completely immersed in the material (for example in a bung-hole drum). Oozing of the material is not a problem for such materials.

Depending on the application and the material, our scoop piston pumps can be pneumatically or hydraulically driven.

A typical characteristic of metering with a scoop piston pump is the slight pulsation that occurs when the material is discharged, due to the upwards and downwards movement of the pump. For many manual applications, this slight pulsation is not a problem.

The discharge fluctuations can also largely be compensated with a material pressure regulator that is integrated into the system downstream of the scoop piston pump. For applications requiring particular precision and uniformity, however, our gear pump technology may be the better option.

Fitted in 2-component systems with a metering pump

Examples of 1-component systems based on scoop piston pump technology include the “monoflow 20” and the “monoflow 200” metering units. If scoop piston pumps are fitted in 2-component systems, we normally also fit a metering pump (“dispenser”) which is filled by the scoop piston pump.

Metering pumps are displacement pumps (or reciprocating pumps); the material pressure at the inlet and outlet thus normally depends on the system. However, our 2000-0221-0000T series metering pump provides an exactly determined volume per stroke, irrespective of the pressure ratios: As the angle degree of the rocker is adjustable, strokes can be regulated, permitting the metering quantity of the B component to be adjusted.

Both the scoop piston pump technology and the combined metering system (consisting of a scoop piston pump and a metering pump) are widely used in many industries, such as the processing of silicone, polyurethanes and polysulphides. Be it for adhesive or sealing technology – our systems impress with their strong performance and wide range of applications.