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FEATURE
• Durable and robust
• Due to pipe diameter, usually 50-100mm, the pump can draw
water from very narrow sumps.
• Up to 6 hours of continuous pumping based on a 5 litre fuel
tank.
• Depending on the specific type of fuel pump (trash, slurry or
clean water), can pump suspended solids of up to 32mm
Disadvantages of fuel driven pumps
• Cannot be used indoors, carbon monoxide exhaust fumes can
be harmful
• Suction depth (the difference between the pump inlet and
water level) is limited to between 1 and 3.5m
• Fuel contamination is a possibility
• A petrol pump needs to be serviced; a pump that works in
dusty area will need to be serviced more regularly than a
pump that works in a ‘clean air’ environment.
• Fuel driven pumps could be a fire hazard
• Pump unit must be primed before use
It is worth noting that there are two types of fuel driven pumps,
petrol and diesel. Diesel driven pumps are considerably more
expensive, in some cases double the cost, because they: have a lot
fewer spare parts than that of petrol, therefore spare parts are more
readily available; are a lot more robust and reliable; have lower fuel
consumption; are safer to operate due to diesel having a lower flash
point, and is therefore less flammable.
Electrical submersible drainage pumps
Drainage pumps are a sealed pump unit that is installed under
water, with the use of an electrical motor that rotates the shaft
and in turn the impellor, water is drawn in through the bottom of
the pump and then pumped through a delivery hose, no smaller
than 50mm, out of the desired area. These pumps usually come
complete with a float switch connected so that unit that will
automatically switch off the pump if the water level gets too low.
Advantages of a drainage pump:
• Easy installation: no suction hoses required, only a delivery
hose
• Pumping heads up to 12m
• Can be used in all-weather conditions
• Pumping solids up to 50mm, depending in pump type,
therefore up to Category 3 wastewater can be pumped.
• No priming needed
Disadvantages of a drainage pump:
• Limited pressure
• Power supply needed
• Bulkier, so space limitations apply
• Drainage pumps that have a float switch are not to be used in
continuous duty applications. PA
www.plumbingafrica.co.za
August 2020 Volume 26 I Number 06