The TSURUMI KTZ47.5 is a heavy-duty submersible dewatering pump from Tsurumi's KTZ series (officially classed as a general construction pump). It has a 100 mm (4-inch) discharge and a 7.5 kW 2-pole three-phase motor. KTZ is Tsurumi's flagship line of drainage pumps, combining a cast-iron body with a wear-resistant semi-open high-chromium cast-iron impeller. It is built for construction sites, quarries and mines, and handles muddy site water (up to 10% dry matter, pH 5–9, solids up to 12 mm).
Selection note: the KTZ47.5 and the KTZ67.5 share the same 7.5 kW motor. The KTZ47.5 (100 mm) gives more head, up to 40 m; the KTZ67.5 (150 mm) moves more water, up to 2,030 L/min, with a 31 m maximum head and 20 mm solids passage. The KTZ47.5 is a dewatering pump, not a slurry pump, and is not suited to dense slurry or sand transfer (Tsurumi's agitator-equipped slurry pumps are the KTD series). It has no automatic operation, and it is not on Tsurumi's list of models for the seawater-resistant kit. For a 100 mm pump in seawater, consider the KTZ411 seawater-resistant version.
Key features
- Top-discharge, side-flow design: water flows up around the motor, so the motor stays cooled even when exposed to air, and the body stays slim enough for confined spaces. Keep the water level at 190 mm (W1) or above for continuous running.
- Multi-directional hose coupling: the discharge can be set vertical or inclined, so the hose does not kink.
- High-chromium cast-iron semi-open impeller: resists wear from abrasive particles. The 420 stainless steel shaft is quench-hardened where it meets particles.
- Dual inside mechanical seals: silicon carbide (SiC) faces housed in the oil chamber, isolated from abrasion and corrosion. Tsurumi rates SiC at five times the corrosion, wear and heat resistance of tungsten carbide.
- Oil Lifter (Tsurumi original): keeps the seal faces lubricated and cooled even when the oil level falls to about one third of normal.
- Seal pressure relief ports and 304 stainless steel labyrinth ring: fitted on models of 7.5 kW and above. The relief ports mean the mechanical seals only see the submergence pressure of the sump.
- Built-in circle thermal protector (CTP): cuts the motor circuit directly on excessive heat or overcurrent.
- Anti-wicking cable entry and cable clip: stops water creeping into the motor by capillary action if the cable sheath is damaged, while the clip protects the cable against pulling.
Applications
- Construction sites: excavation and basement dewatering, temporary site drainage
- Quarries and aggregate yards: removal of water carrying sand and silt
- Mines: pit dewatering (water only, not slurry transfer)
- Confined spaces: the slim body suits sumps and pits with limited room
Performance
The 40 m maximum head is the head at near-zero flow, and the 1,400 L/min (84 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. Compared with the lower-powered 100 mm models, the KTZ43.7 (18 m) and KTZ45.5 (22.5 m), the KTZ47.5 delivers considerably more head. Where the head is lower and you need more flow, consider the KTZ45.5 (1,740 L/min) or the KTZ67.5 (2,030 L/min); for more head, consider the KTZ411 (100 mm, 11 kW, 48.5 m maximum head).
Technical specifications
TSURUMI KTZ47.5 technical specifications (50 Hz)
| Item | Specification |
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| General |
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| Model | KTZ47.5 |
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| Series | KTZ (general construction pump, heavy-duty submersible dewatering) |
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| Discharge bore | 100 mm (4 in) |
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| Discharge connection | Hose coupling (vertical or inclined) |
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| Hydraulic performance |
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| Max. head (at zero flow) | 40 m |
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| Max. capacity (curve end point) | 1,400 L/min (84 m³/h) |
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| Max. solids size | 12 mm |
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| Electrical |
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| Motor output | 7.5 kW |
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| Motor | Dry-type induction motor, 2-pole, IP68, insulation class F, continuous-duty rated |
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| Power supply | 3-phase 50 Hz (voltage as per nameplate) |
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| Speed | 2,945 rpm (Tsurumi Europe 400 V 50 Hz data) |
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| Rated current | 15.1 A (Tsurumi Europe 400 V 50 Hz data; Hong Kong supply 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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| Cable | 8 m, chloroprene rubber sheath |
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| Seals and lubrication |
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| Shaft seal | Dual inside mechanical seals, silicon carbide (SiC) faces, with Oil Lifter |
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| Seal protection | Seal pressure relief ports; 304 stainless steel labyrinth ring |
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| Lubricant | Turbine oil ISO VG32, 760 ml |
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| Bearings | Shielded ball bearings |
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| Materials |
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| Impeller | Semi-open, high-chromium cast iron |
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| Suction cover | Ductile cast iron |
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| Casing, frame and motor housing | Grey cast iron |
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| Shaft | 420 stainless steel |
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| Liquid limits |
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| Liquid | Drainage water (water carrying 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 | 10% |
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| Max. submersion depth | 50 m |
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| Dimensions and weight |
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| Dry weight (excl. cable) | 101 kg |
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| Overall height | 812 mm |
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| Min. water level for continuous running (W1) | 190 mm |
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Sources: Tsurumi KTZ/KTZE/KTD series catalogue (IB107) and Tsurumi Europe KTZ47.5 data (400 V 50 Hz). Voltage and rated current of the Hong Kong supply version are as per the nameplate.
KTZ series comparison: 100 mm and 7.5 kW models
Tsurumi KTZ series model comparison (50 Hz)
| Model | Discharge | Power | Max. head | Max. capacity | Dry weight |
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| KTZ43.7 | 100 mm | 3.7 kW | 18 m | 1,440 L/min | 60 kg |
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| KTZ45.5 | 100 mm | 5.5 kW | 22.5 m | 1,740 L/min | 74 kg |
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| KTZ47.5 (this product) | 100 mm | 7.5 kW | 40 m | 1,400 L/min | 101 kg |
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| KTZ411 | 100 mm | 11 kW | 48.5 m | 1,440 L/min | 133 kg |
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| KTZ415 | 100 mm | 15 kW | 55 m | 1,980 L/min | 146 kg |
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| KTZ422 | 100 mm | 22 kW | 71 m | 2,750 L/min | 295 kg |
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| KTZ67.5 | 150 mm | 7.5 kW | 31 m | 2,030 L/min | 100 kg |
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Optional accessories
- Float switch with a motor starter or control panel: the KTZ47.5 has no built-in level control, so unattended automatic on/off needs a float switch and a control panel with overload protection.
- Motor starter or control panel with overload and phase-failure protection, set to the nameplate rated current. Star-delta starting is available on request.
Safety and installation
- Three-phase supply only. Installation and wiring must be carried out by a registered electrical worker, with proper earthing and a motor starter that provides overload and phase-failure protection.
- Check the voltage and current on the nameplate before connecting, and confirm the direction of rotation after wiring.
- If the built-in thermal protector trips, find the cause of the overheating or overcurrent before running the pump again. Always isolate and lock out the power before inspection or servicing.
- The pump weighs about 101 kg dry. Lift and lower it by its handle or eye bolt with a chain or rope and suitable lifting equipment. Never lift it by the power cable, and protect the cable from pulling and cuts.
- Keep the water level at 190 mm (W1) or above for continuous running. Use a strainer and keep the pump from being buried in sludge.
- The standard model is not seawater-resistant. Do not pump liquids above 40 °C or outside pH 5–9, and do not use it with flammable or explosive liquids or atmospheres (the pump is not explosion-proof).
Wear parts and routine checks
- Main wear parts: impeller, suction cover and mechanical seals. Wear is faster in abrasive or corrosive service, and flow drops as these parts wear.
- Check the oil in the oil chamber (turbine oil ISO VG32, 760 ml) regularly. If it is cloudy or contains water, have the shaft seals inspected promptly.
