The TSURUMI KRS1022 is the largest-bore heavy-duty submersible dewatering pump in Tsurumi's KRS series (officially classed as a general construction pump). It has a 250 mm (10-inch) discharge and a 22 kW 4-pole three-phase motor. With a maximum capacity of 12,000 L/min, it is the highest-flow, lowest-head model in the standard KRS range, built to move large volumes of water against a low total head: flood and storm drainage, boosting drainage pumping stations, reservoir and dock dewatering, and large excavations.
The KRS1022 is also the only model in the standard KRS range with a closed impeller and a top-discharge, flow-thru design. The impeller is ductile cast iron and the casing and motor frame are grey cast iron, paired with a low-speed motor. It handles stormwater, groundwater and wash water carrying a small amount of sand and silt (up to 15% dry matter, pH 5–9, solids up to 25 mm).
Selection note: the KRS1022 is a high-flow, low-head pump. Its maximum head is only 12.2 m, so it is not suited to high lifts or long-distance transfer. For more head, choose the KRS815 (21.5 m), KRS822L (26 m) or KRS822 (34.8 m). It is also not a slurry pump: it has no agitator and no high-chrome wear parts, so it is not suitable for settled sludge, dense sand slurry, desilting or dredging. For that duty, choose the KRD611 or KRS-200 slurry pumps, which have a high-chrome impeller and an agitator.
Key features
- Top-discharge, flow-thru design: unique to the KRS1022, it gives maximum motor cooling, allows continuous operation at low water levels and extends dry-run capability. Keep at least 450 mm of water for continuous running and do not run it dry for long periods.
- Closed ductile-iron impeller: the only closed impeller in the standard KRS range; ductile cast iron resists wear from abrasive particles.
- Double inside mechanical seals: silicon carbide (SiC) on SiC faces, upper and lower, in an isolated oil chamber, with Tsurumi's original Oil Lifter keeping the seal faces lubricated and cooled even when the oil drops to one third of its normal level.
- Two oil seals: nitrile rubber lip seals act as dust seals, protecting the mechanical seals from abrasive particles.
- Built-in circle thermal protector (CTP): cuts the motor circuit directly on excessive heat or overcurrent.
- Anti-wicking cable entry: stops water creeping along the cable cores into the motor if the sheath is damaged or the cable end is submerged, and also blocks moist air and condensation. A cable clip provides strain relief.
- Low-speed 4-pole motor: continuous-duty dry-type induction motor, IP68, insulation class F, about 1,440–1,470 rpm at 50 Hz, paired with a cast-iron body for long service life.
- Starting: direct-on-line (DOL) as standard, star-delta to order, and suitable for soft starters and variable-frequency drives (VFD).
Applications
- Flooding and storms: floodwater drainage, emergency storm drainage, boosting drainage pumping stations
- Reservoirs and docks: reservoir drainage, shipyard dock dewatering
- Construction and civil works: large excavation dewatering; tunnel, bridge and dam works
- Temporary drainage: provisional sewage drainage, simple rainwater drainage
Performance
The 12.2 m maximum head is the head at near-zero flow, and the 12,000 L/min (about 720 m³/h) maximum capacity is the end point of the performance curve. The two do not occur together: actual flow falls as total head (static head plus hose friction loss) rises. Select the pump from the performance curve using your site's total head, and avoid continuous running on the dashed part of the curve.
Technical specifications
TSURUMI KRS1022 technical specifications (50 Hz)
| Item | Specification |
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| General |
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| Model | KRS1022 |
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| Series | KRS (general construction pump, heavy-duty submersible dewatering) |
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| Discharge bore | 250 mm (10 in) |
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| Discharge connection | Hose coupling (standard) |
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| Discharge design | Top discharge, flow-thru |
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| Hydraulic performance |
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| Max. head (at zero flow) | 12.2 m |
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| Max. capacity (curve end point) | 12,000 L/min (720 m³/h / 12 m³/min) |
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| Max. solids size | 25 mm |
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| Electrical |
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| Motor output | 22 kW |
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| Motor | 4-pole dry-type induction motor, continuous duty, IP68, insulation class F |
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| Speed | approx. 1,440–1,470 rpm (50 Hz) |
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| Power supply | 3-phase 50 Hz (voltage as per nameplate) |
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| Starting method | Direct-on-line (DOL); star-delta available to order; suitable for soft starters and VFDs |
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| Motor protection | Built-in circle thermal protector (CTP) |
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| Cable | 10 m, chloroprene rubber sheath, anti-wicking cable entry |
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| Seals and bearings |
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| Shaft seal | Double inside mechanical seals, SiC on SiC (upper and lower), oil-lubricated, with Oil Lifter |
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| Oil seals | Nitrile rubber lip seals × 2 |
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| Lubricant | Turbine oil ISO VG32, 4,000 ml |
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| Bearings | Double-shielded deep-groove ball bearings (C3), permanently lubricated |
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| Materials |
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| Impeller | Closed, ductile cast iron (EN-GJS-700-2) |
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| Pump casing, suction cover | Grey cast iron (EN-GJL-200) |
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| Motor frame | Grey cast iron (EN-GJL-200) |
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| Shaft | 420 stainless steel (X30Cr13) |
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| Liquid limits |
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| Liquid | Stormwater, groundwater, wash water and site water with a small amount of sand and silt |
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| Liquid temperature | 0–40 °C |
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| pH | 5–9 |
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| Max. dry matter | 15% |
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| Max. submersion depth | 40 m |
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| Dimensions and weight |
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| Dry weight (excl. cable) | 400 kg |
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| Dimensions (L × W × H) | 527 × 524 × 1419 mm |
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| Min. water level for continuous running | 450 mm |
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Sources: Tsurumi KRS/KRD series catalogue (IB111, 2025 edition), Tsurumi model specification sheets and Tsurumi Europe KRS series data (50 Hz). Older official sheets list a dry weight of 390 kg. Voltage, cable size and rated current of the Hong Kong supply version are as per the nameplate and confirmation from the Hong Kong agent.
KRS series comparison: 200 mm and larger
Tsurumi KRS series model comparison (50 Hz)
| Model | Discharge | Power | Max. head | Max. capacity | Max. solids |
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| KRS811 | 200 mm | 11 kW | 17.5 m | 5,500 L/min | 30 mm |
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| KRS815 | 200 mm | 15 kW | 21.5 m | 6,400 L/min | 25 mm |
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| KRS822L | 200 mm | 22 kW | 26 m | 5,900 L/min | 25 mm |
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| KRS822 | 200 mm | 22 kW | 34.8 m | 5,300 L/min | 25 mm |
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| KRS1022 (this product) | 250 mm | 22 kW | 12.2 m | 12,000 L/min | 25 mm |
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What's in the box
- KRS1022 pump with attached 10 m cable × 1
- Hose coupling × 1
Optional accessories
- Male threaded discharge coupling, in place of the standard hose coupling.
- Float switch. On a three-phase pump it must switch a control-panel contactor, never the motor directly.
- Motor overload protector or control panel, set to the nameplate rated current.
- A high-temperature-liquid version (up to 60 °C) is a special factory build, not an accessory; ask for availability.
Safety and installation
- The pump weighs about 400 kg dry. Lift it by its handle with a chain or shackle rated for the load. Never lift it by the cable or the hose.
- Stand the pump on a firm or raised base so it does not sink into silt.
- Electrical connection must be made by a registered electrical worker in line with Hong Kong wiring regulations, with earth-leakage protection. Set the overload relay to the nameplate rated current.
- A 22 kW direct-on-line start draws a high starting current, so the cable, breaker and generator or transformer must be sized for it.
- Check rotation before first use: at start-up the pump body should kick anticlockwise when viewed from above. If it turns the wrong way, have an electrician swap two phases. Do not hold the handle while checking.
- After the built-in motor protector trips, the motor restarts automatically once it cools. Always isolate and lock off the power before inspection or servicing.
- Do not run continuously below a 450 mm water level, avoid prolonged dry running, and do not run continuously on the dashed part of the curve near shut-off.
- Tsurumi lists no seawater-resistant kit for the KRS1022, so it is not recommended for seawater or brackish water. Do not pump liquids outside pH 5–9, oily or chemical liquids, or flammable liquids; liquids above 40 °C need the high-temperature version.
Wear parts and routine checks
- Main wear parts: impeller, suction cover, mechanical seals and the two oil seals. With long running in sandy water, the impeller and suction cover gradually wear and flow drops.
- Check the oil in the oil chamber regularly (turbine oil ISO VG32, 4,000 ml). If it is milky, cloudy or contains water, have the shaft seals inspected promptly.
