Reciprocating compressor pump and diphragm pump drive principle

Wobble plate and swash plate drive units

Another type of drive unit uses a plate arranged at an angle to the linear motion axis of the plunger rod. These designs are available both with and without an upstream reduction gearbox. 

A wobble plate drive mechanism is a design in which the plate rotates wobbling relative to the housing and the plunger rod axis. The axial portion of the wobbling movement can be used to drive the plunger rod. The plunger rod usually has a sliding shoe that picks up the movement of the wobble plate, see figure 1

Figure 1: Example of a wobble plate diaphragm pump

A swash plate drive unit is a design in which the inclined position of the plate is fixed and the plunger rod moves in a circular orbit in a housing part. Here again, the axial movement is usually picked up from the plate using a sliding shoe, see figure 2

Figure 2: Schematic drawing of a swash plate drive unit

A special case of the swash plate drive unit consists of a driven swash plate that circulates instead of wobbling, and drives the plunger rod using a polar coupling rod, as shown in figure 3

Figure 3: Example of a wobble plate drive mechanism with polar coupling

When implementing stroke-adjustable drive units, the wobble plates or swash plates have an adjustable-angle design. Wobble plate and swash plate drive units can drive multiple plunger rods arranged in a circle simultaneously. 

This type of drive unit is not particularly widespread in metering pump engineering. 

Highly compact, powerful hydraulic pumps can be implemented, but for space reasons, this type is less suitable for implementing a modular diaphragm pump