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Hydraulic Pump for Underground Drainage
Hydraulically driven drainage pump for underground chambers, basement sumps, utility shafts, and below-grade drainage systems where electrical equipment in wet environments is restricted
The Hydraulic Pump for Underground Drainage is a hydraulically driven submersible pump designed for water removal from below-grade chambers, basement sumps, utility shafts, and underground drainage systems. The pump operates from an external hydraulic power unit, with no electrical motor or cable in the submerged assembly, which suits underground environments where moisture, confined access, and restricted electrical installation make electric submersibles difficult to deploy and maintain. The unit delivers up to 300 m³/h at heads up to 50 meters, sufficient to lift water from deep sumps to surface discharge points. The 40 mm solids passage handles water carrying silt, sand, and small debris accumulated in underground drainage systems. The pump body is cast iron with a replaceable wear plate, and the impeller is semi-open cast iron. The compact submerged profile allows lowering through narrow manholes and into chamber openings, and the hydraulic couplers permit connection to a surface power unit or existing hydraulic circuit.
The pump body is compact enough to pass through standard manhole openings, provided the discharge outlet and hydraulic couplers are positioned correctly during lowering. Buyers should provide the manhole opening dimensions and the chamber depth at inquiry stage. For openings narrower than the discharge flange diameter, a flanged discharge connection can be supplied with a removable flange for lowering, then reconnected at the pump body.
The required head is the vertical distance from the sump water level to the discharge point, plus friction losses in the discharge hose or pipe. For a 30-meter vertical lift with 80 meters of discharge hose, the total head requirement is typically 35 to 40 meters. The pump's maximum head of 50 meters provides margin for friction losses and discharge pressure. Buyers should provide the vertical lift and discharge line length so the required head can be confirmed.
The semi-open impeller passes solids up to 40 mm in diameter, covering silt, sand, small stones, and debris typical of underground drainage systems. For water containing larger objects or fibrous material, 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 unit: 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, flow, and vertical lift 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 pump can be operated with a level control valve or float switch on the power unit circuit to start and stop automatically based on water level. However, unattended operation in an underground chamber requires consideration of hose security, access control, and gas monitoring if personnel must enter. Buyers should confirm the chamber ventilation and access arrangements before planning unattended operation, and confirm whether the power unit supports automatic start-stop control.
After each dewatering cycle, flush the pump casing and impeller with clean water to remove silt and sediment. Inspect the hydraulic couplers and hoses for abrasion or damage. Check the impeller and wear plate condition, and replace worn parts as needed. Verify that the pump rotates freely. For units in standby, run the pump briefly each month to confirm operation and prevent seal sticking.
A complete inquiry should include: required discharge flow in cubic meters per hour; vertical lift from sump to discharge point in meters; discharge line length and diameter; power unit hydraulic flow in liters per minute and maximum pressure in bar; relief valve setting; coupler type; manhole or chamber opening dimensions and sump depth; expected solids content of the water; and the number of chambers to be served. For municipal or fleet procurement, indicate the estimated annual quantity and whether the specification must remain fixed across repeat orders.
