Vertical plastic centrifugal pumps are used almost exclusively under difficult conditions. Temperature of the medium, solid particles in the liquid or an extremely high switching rate of the pumps is often the cause for pump failures, expensive repairs and downtimes.
The new KGK series, B80 vertical plastic centrifugal immersion pumps are designed for use in closed, unpressurised containers, pools or excavations. Special design features enable a long service life and safe operation. Special vapour seals protect the pump bearings from gases and vapours. Permanently installed pumps are used to pump acid solutions, hydroxides, salts in varying concentrations, strong acid mixtures, galvanising solutions, chemical waste fluids, chlorinated hydrocarbons, glycol ether, emulsions, sea water and hot spring water etc. with a delivery rate of up to 80 m³/h and a delivery head of up to 41 m wc at a density of max. 2 kg/dm³.
The single stage centrifugal pumps have an immersion depth between 500 and 4000 mm as well as a max. suction pipe extension of up to 2000 mm. The pumps are available in the materials PP (polypropylene), PVDF (polyvinylidene fluoride) and PVC (polyvinyl chloride) with a high resistance to chemicals. For the “G” version, the immersed shaft guide tube and the rising tube are clad with PP-GRP (vinylester-reinforced fibreglass). This increases the strength and limits lengthwise expansion. Liquids up to a temperature of 90°C can be pumped, the bearing load is reduced and the service life of the pump therefore is increased.
The KGK series: Quality in detail
The pump has a compact bearing housing with a robust plastic bearer plate. The bearing housing is treated with an acid protection paint, is resistant to corrosion and accommodates the elastic coupling with axial and radial bearings. The design was kept as compact as possible, which significantly reduces vibrations. To contain the vapours and gases which arise inside the pump, in the standard version, at the height of the bearer plate, a vapour seal is fitted which works dry, both in static and dynamic conditions. In addition to the standard lip seals which work dry, a mixed seal is also available which has a dynamic deflector ring that works efficiently up to a pressure of about 300 mbar. The innovative “liquid barrier” system can be supplied with compressed air or liquid via a rapid-action coupling. The laminar spread of the compressed air builds up a counter-pressure, completely blocking poisonous vapours and gases so these can neither get to the mechanical parts nor escape to the outside, thus protecting the environment.
Optionally the pump can be equipped with an external flushing line for rinsing the guide bushings. The pump shaft made of carbon steel is completely coated with plastic that is resistant to the pumped medium. The shaft is guided at the top by a roller bearing and then along its length by plain bearings. This protects the pump as far as possible from cavitation damages.
The plain bearings are made of PTFE/glass on ceramic for general applications or SiC/SiC for abrasive media. The plain bearings are lubricated by the pumped medium or can optionally be supplied with an external medium. The bearing can be simply replaced and in case of a bearing damage it can be avoided that the complete pump housing is disrupted.
Pump hydraulics is optimised and available are open and closed impellers. The impellers are hydraulically unloaded by blades so that only minimum axial forces impact on the pump bearings. A protective filter in the base as standard protects the pump against contamination and solids at a minimum flow loss.