The Impact Pump is a range extender that enables surface pumps to access deep groundwater.
Surface pumps, in which motors, sliding seals and electronics are located in air at surface level, are generally cheaper, more efficient, easier to maintain and longer lasting than submersible pumps. However they can only draw water from a maximum of 7m depth (often much less). In most of the world, (>90% of Sub-Saharan Africa), groundwater is located beyond suction depth. In these cases, submersible pumps are required, which push water up from below. This currently involves situating motors and serviceable parts below the waterline, often in confined conditions. Efficiency is limited by small rotor and impeller diameters and failures are common, due to dry running (causing motor burnouts), and damage caused by silt and grit. Maintenance involves removing the pump from the well, which is often arduous and difficult, particularly where hard pipes are used.
The Impact Pump is a “range extender” that uses the Joukowski effect to enable most surface pumps to access deep water without sliding seals or electronics below ground. It will initially be available in Kenya, with rollout across East Africa shortly afterwards.
Efficient: It is highly efficient (over 90% with steel pipes, over 80% with plastic). It can enable its surface drive pump to operate close to its Best Efficiency Point (BEP) across a much greater range of input powers, heads and flows than submersibles, leading to overall efficiency improvements, particularly in the context of solar power and centrifugal pumps.
Long-lived: It is inherently robust, enabling long warranty periods and service intervals.
Versatile: It can be powered by more or less any suitably powered surface pump.
Tested: Extensive testing including developing world field trials have been carried out with grid-centrifugal, solar (helical and piston types), petrol-powered and human-powered drive pumps.
Durable: It is highly tolerant of silt and grit, which can be separated off as sediment in a surface storage tank, so the drive pump is protected too. It can run dry (pumps air), solving a major challenge faced by electrically-powered submersibles.
Variable: It enables low starting flows, particularly in the context of solar power, as the head seen by the drive pump is “de-coupled” from the static lift it pumps against. This also enables it to be set up such that the drive pump operates close to its Best Efficiency Point (BEP) across a wide range of power inputs (not otherwise possible).
Dual-use: It can distribute water for short periods at very high flow rates with low input power, using the drive pump as a conventional low-head surface pump. For solar pumps, where surface storage is often needed, this enables expensive raised tanks to be replaced with cheaper covered ponds. This also enables rainwater catchment, which is not possible with raised tanks.
See www.impactpumps.com for regular updates.