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Hydraulic Centrifugal Drainage Pump
Hydraulically driven centrifugal pump for general dewatering, sump drainage, and water transfer where electrical submersibles are unsuitable and moderate solids tolerance is required
The Hydraulic Centrifugal Drainage Pump is a hydraulically driven submersible centrifugal pump designed for general dewatering and water transfer duties. The pump uses a semi-open impeller and volute casing to generate head through radial flow, delivering up to 350 m³/h at heads up to 45 meters. Power is supplied by an external hydraulic power unit through hoses, with the hydraulic motor integrated into the sealed pump housing. No electrical motor or cable is submerged, simplifying safety management in wet sumps, tanks, and excavations. The pump passes solids up to 35 mm, making it suitable for water containing sand, silt, and small debris. The casing is cast iron with a replaceable wear plate, and the impeller is cast iron with a hardened leading edge. The unit is suited to batch procurement by contractors, municipal maintenance departments, and industrial plants requiring a general-purpose hydraulic dewatering pump.
The semi-open impeller passes solids up to 35 mm in diameter, including sand, silt, and small debris. This covers typical construction site and municipal sump conditions. For applications with fibrous material or larger objects, a strainer with larger openings or a trash pump should be specified. Buyers should confirm the expected solids profile at inquiry stage so the impeller and strainer configuration can be matched to the application.
Matching requires three inputs from the power pack: hydraulic flow in liters per minute, maximum pressure in bar, and relief valve setting. The pump's hydraulic motor displacement is selected so that the available flow produces the required impeller speed. Providing these figures along with the required discharge head and flow allows the supplier to specify the correct motor. If the power unit model is known but the flow figures are not, the supplier can typically match the motor from the model number.
The hydraulic motor and shaft bearings are lubricated by the hydraulic circuit rather than the pumped water, so the pump can run dry without the immediate bearing failure associated with electric submersibles. However, the mechanical seal relies on the pumped medium for cooling, and extended dry running accelerates seal face wear. For applications where water level fluctuates, a level control valve or float switch on the power pack circuit is recommended.
The discharge outlet size is determined by the casing casting and is not field-changeable on a standard unit. Buyers requiring 150 mm outlet must specify this at order stage. For buyers holding existing 100 mm hose and coupling inventory, the 100 mm model is the standard configuration. Custom outlet configurations may be available subject to minimum order quantity, which should be confirmed with the supplier.
For fleet operators, the recommended wear part inventory includes one wear plate and one impeller per pump head, plus a mechanical seal cartridge for every four pump heads. This ratio reflects typical wear rates in sandy and silty service. Buyers should confirm the supplier's service parts lead time before finalizing fleet quantities, as replenishment delays directly affect pump availability.
Each pump head is pressure tested on the hydraulic circuit to verify seal integrity and joint tightness. The impeller clearance is measured and recorded. A test run confirms free rotation of the shaft assembly. Buyers requiring witnessed testing, third-party inspection certificates, or specific documentation for site approval should specify these at the inquiry stage.
A complete inquiry should include: required discharge flow in cubic meters per hour; required head in meters; power pack hydraulic flow in liters per minute and maximum pressure in bar; relief valve setting; required discharge outlet size; hose length and coupler type; expected submersion depth; and the expected solids content of the water. For fleet orders, indicate the estimated annual quantity and whether the specification must remain fixed across repeat orders.
