Stirrer keeps crusts away

The machine is designed to deal with a pond of 3.5 million litres.

The stirrer, made extensively from high-grade galvanised steel, has a triangular pedestal designed to be bolted to a concrete pad at the edge of the pond. 

A deep, square-section support tube, in this case 8m long, can be tailored to individual situations; it has a large propeller surrounded by a shroud not unlike an empty oil drum. The interaction between the propeller and the shroud is designed to increase the velocity of the liquid and to create a vortex that keeps solids in suspension and helps reduce the build-up of silted areas in a pond.

Depth control is achieved by a heavy-duty chain arrangement at the pedestal end, with an integral foot at the business end designed to protect the liner from damage. 

Also at this end of the unit, a mechanical linkage can be adjusted to alter the angle of the propeller/shroud to mix thoroughly. 

Power comes from a shore-mounted electricity supply from 4 to 7.5kW; gearbox reductions at the propeller end can be tweaked to a range of speeds and power requirements.