The TSURUMI KRD47.5 is a heavy-duty submersible slurry pump with agitator from Tsurumi's KRD/KRS (Slurry) series, classed by Tsurumi Hong Kong as a construction slurry pump. It has a 100 mm (4-inch) discharge and a 7.5 kW 4-pole three-phase motor, and was formerly sold as the KRS2-100. A high-chrome cast-iron agitator on the shaft stirs up settled solids so they can be pumped away, while the semi-open impeller and suction plate are also high-chrome cast iron for strong wear resistance. It is designed for slurries laden with silt, earth, sand or other particulate, with solids up to 30 mm.
Selection note: the KRD47.5 is an agitator-type slurry pump for settled sediment and sandy slurry. If the job is mainly removing site water that carries only a little sand rather than settled slurry, a KRS-series heavy-duty dewatering pump without an agitator, such as the KRS811, may suit better. The KRD47.5 is not intended for sewage or wastewater containing fibrous solids.
Key features
- High-chrome cast-iron agitator: mounted on the shaft and paired with a dedicated strainer, it suspends settled solids so they are drawn in smoothly.
- High-chrome wear parts: the semi-open impeller and the suction plate are high-chrome cast iron. When wear reduces performance, replacing the suction plate restores it.
- Top-discharge, side-flow design: keeps the motor cooled even when it runs exposed to air, and reduces the overall pump diameter for confined spaces.
- Double inside mechanical seals: silicon carbide (SiC) faces in an oil chamber with Tsurumi's Oil Lifter, which keeps the seal faces lubricated and cooled down to about one third of the normal oil level. The oil seal doubles as a dust seal that shields the mechanical seal from abrasive particles.
- Built-in circle thermal protector (CTP): cuts the motor circuit directly on excessive heat or overcurrent.
- Anti-wicking cable entry and cable clip: limit water travelling along the cable into the motor.
- Continuous-duty 4-pole motor: dry-type induction motor, insulation class F, synchronous speed 1,500 min⁻¹ at 50 Hz.
Applications
- Construction sites: pumping muddy, sediment-laden water from excavations, sumps and pits
- Construction slurry: transferring slurry containing silt, earth, sand or other particulate (solids up to 30 mm)
- Sediment removal: clearing settled sand and silt from sump pits and tank floors
The standard model handles liquids at 0–40 °C, pH 5–9 and up to 20% dry matter. It is not for seawater, chemicals or corrosive liquids, hot liquids, flammable liquids, or sewage containing fibrous solids.
Performance
The 17.1 m maximum head is the head at near-zero flow, and the 2,350 L/min (about 141 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, and drops further when pumping denser slurry. Select the pump from the performance curve using your site's total head. These are 50 Hz figures; the 60 Hz model is a separate build whose performance follows the official curve. For more flow or head, consider the KRD611 (22 m) or KRS-200 (31 m).
Technical specifications
TSURUMI KRD47.5 technical specifications (50 Hz)
| Item | Specification |
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| General |
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| Model | KRD47.5 (formerly KRS2-100) |
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| Series | KRD/KRS (Slurry), heavy-duty submersible slurry pump with agitator |
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| Discharge bore | 100 mm (4 in) |
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| Discharge connection | Hose coupling (standard) |
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| Hydraulic performance |
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| Max. head (at zero flow) | 17.1 m |
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| Max. capacity (curve end point) | 2,350 L/min (about 141 m³/h / 2.35 m³/min) |
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| Max. solids size | 30 mm |
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| Electrical |
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| Motor output | 7.5 kW |
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| Motor | 4-pole dry-type induction motor, continuous-duty rated, insulation class F |
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| Synchronous speed | 1,500 min⁻¹ (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 on request |
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| Motor protection | Built-in circle thermal protector (CTP) |
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| Standard cable length | 8 m (chloroprene rubber cable) |
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| Seals and lubrication |
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| Shaft seal | Double inside mechanical seals, silicon carbide (SiC) faces, oil-lubricated, with Oil Lifter |
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| Oil seal (dust seal) | NBR |
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| Lubricant | Turbine oil ISO VG32, 2,300 ml |
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| Materials |
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| Impeller | Semi-open, high-chrome cast iron |
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| Agitator | High-chrome cast iron |
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| Suction plate | High-chrome cast iron |
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| Pump casing, suction cover | Grey cast iron |
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| Motor frame | Grey cast iron |
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| Shaft | 420 stainless steel |
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| Liquid limits |
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| Liquid | Slurry containing silt, earth, sand or other particulate |
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| Liquid temperature | 0–40 °C |
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| pH | 5–9 |
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| Max. dry matter | 20% |
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| Dimensions and weight |
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| Dry weight (excl. cable) | 154 kg |
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| Dimensions (L × W × H) | 418 × 379 × 936 mm |
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| Lowest running water level | 270 mm |
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Sources: Tsurumi KRS/KRD series catalogue (IB111), Tsurumi Hong Kong KRD/KRS slurry pump page and Tsurumi Europe KRD series data (head, capacity, liquid limits and lowest running water level are 50 Hz values). Voltage and rated current of the Hong Kong supply version are as per the nameplate; obtain the delivery specification sheet before use.
KRD/KRS slurry series comparison
Tsurumi KRD/KRS slurry series model comparison (50 Hz)
| Model | Discharge | Power | Max. head | Max. capacity | Max. solids |
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| KRD35.5 | 80 mm | 5.5 kW | 15.8 m | 1,670 L/min | 30 mm |
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| KRD47.5 (this product) | 100 mm | 7.5 kW | 17.1 m | 2,350 L/min | 30 mm |
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| KRD611 | 150 mm | 11 kW | 22 m | 3,250 L/min | 30 mm |
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| KRS-200 | 200 mm | 18 kW | 31 m | 4,800 L/min | 30 mm |
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Optional accessories
- Discharge hose sized for the 100 mm outlet, in the length your site needs.
- Motor-protection starter or control panel (supplied separately): three-phase pumps must be connected through a panel with overload and earth-leakage protection, with the overload relay set to the nameplate rated current.
- For other Tsurumi accessories (such as hose couplings in other sizes, a seal oil leakage sensor or a jetting system) and the seawater-resistant kit, please ask us about Hong Kong availability.
Safety and installation
- The pump weighs 154 kg dry (excluding cable). Lift it by its handle with suitable lifting gear. Never lift it by the cable or the hose.
- Wiring, earthing and protective devices must be installed by a registered electrical worker in line with local regulations. The built-in CTP does not replace an external motor-protection starter.
- Check the direction of rotation before first use. If it is wrong, have an electrician swap two phases.
- Keep the liquid above the lowest running water level (270 mm) while running, and never run the pump dry.
- Always isolate the power before inspection or servicing. The agitator and impeller edges are sharp; handle them with care.
- The standard model is not seawater-resistant and should not be used in seawater without the seawater-resistant kit. Do not use it with flammable or explosive liquids or atmospheres, or with liquids above 40 °C.
Wear parts and routine checks
- Main wear parts: the high-chrome suction plate, impeller, agitator and mechanical seals. Pumping sandy slurry gradually wears the impeller and suction plate and reduces flow; replacing the suction plate restores performance.
- Check the oil in the oil chamber regularly (turbine oil ISO VG32, 2,300 ml). Cloudy oil, or water or slurry in the oil, indicates mechanical seal wear; have the seals inspected promptly.
