The TSURUMI KTZ33.7 is a submersible heavy-duty dewatering pump from Tsurumi's KTZ series, listed by Tsurumi under Dewatering Pumps. It has an 80 mm (3-inch) discharge and a 3.7 kW 2-pole three-phase motor. KTZ is Tsurumi's flagship line: a cast-iron body paired with a high-chrome cast-iron impeller, built to pump muddy water on construction sites, in quarries and in mines (up to 10% dry matter, pH 5–9, solids up to 8.5 mm).
Selection note: the KTZ33.7 is the standard model. It has no automatic operation and is not seawater-resistant. For automatic level-controlled start and stop, choose the KTZE33.7. For seawater or brackish water, choose the KTZ33.7-SEA seawater-resistant version fitted with the Seawater-Resistant Kit. The KTZ33.7 is a dewatering pump, not a slurry pump, and is not suitable for dense slurry or sand transfer.
Key features
- Top-discharge, side-flow design: the motor stays cooled even when exposed to air, and the slim body fits confined spaces. Keep at least 150 mm of water for continuous running.
- Multi-directional hose coupling: the discharge can be set vertical or inclined so the hose does not fold or kink.
- Semi-open high-chrome cast-iron impeller: resists wear from abrasive 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 drops to about one third of the normal level.
- Oil seal (dust seal): an NBR oil seal gives the mechanical seals extra protection.
- Built-in circle thermal protector (CTP): cuts the motor circuit directly on overheating or overcurrent.
- Anti-wicking cable entry and cable clip: stops water creeping in by capillary action if the sheath is damaged, and protects the cable against pulling.
- Hardened shaft: the 420 stainless steel shaft is quench-hardened where it meets abrasive particles.
Applications
- Construction and civil works: excavation and basement dewatering, temporary site drainage
- Quarries and aggregate plants: removal of water carrying a small amount of silt
- Mines: pit dewatering (water only, not slurry transfer)
Performance
The 29 m maximum head is the head at near-zero flow, and the 900 L/min (about 54 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. For more flow and head from the same 80 mm discharge, consider the KTZ35.5 (5.5 kW, 32 m, 1,100 L/min).
Technical specifications
TSURUMI KTZ33.7 technical specifications
| Item | Specification |
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| General |
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| Model | KTZ33.7 |
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| Series | KTZ (submersible heavy-duty dewatering pump) |
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| Discharge bore | 80 mm (3 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) | 29 m |
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| Max. capacity (curve end point) | 900 L/min (54 m³/h) |
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| Max. solids size | 8.5 mm |
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| Electrical |
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| Motor output | 3.7 kW |
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| Motor | Continuous-duty dry-type induction motor, 3-phase, 2-pole, insulation class F, IP68 |
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| Power supply | 3-phase (voltage as per nameplate) |
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| Synchronous speed | 3,000 min⁻¹ (50 Hz) / 3,600 min⁻¹ (60 Hz) |
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| Rated speed and current (European 400 V 50 Hz version, for reference) | 2,888 rpm; 8 A |
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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 bearings |
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| Shaft seal | Dual inside mechanical seals, silicon carbide (SiC) faces, oil-lubricated, with Oil Lifter |
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| Oil seal | NBR (dust seal) |
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| Lubricant | Turbine oil ISO VG32, 1,250 ml |
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| Bearings | Shielded ball bearings |
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| Materials |
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| Impeller | Semi-open, high-chrome cast iron |
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| Suction cover | Ductile cast iron |
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| Casing, frame, motor housing | Gray cast iron |
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| Shaft | 420 stainless steel |
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| Liquid limits |
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| Liquid | Drainage 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 | 10% |
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| Max. submersion depth | 50 m |
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| Weight and water level |
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| Dry weight (excl. cable) | 60 kg |
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| Min. water level for continuous running (W1) | 150 mm |
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Sources: Tsurumi KTZ/KTZE/KTD series catalogue (IB107), Tsurumi Hong Kong official website and Tsurumi Europe KTZ33.7 data. Rated speed and current are from the European 400 V 50 Hz version; voltage and rated current of the Hong Kong supply version are as per the nameplate.
KTZ series comparison: 80 mm and 3.7 kW models
Tsurumi KTZ series model comparison
| Model | Discharge | Power | Max. head | Max. capacity | Max. solids | Dry weight |
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| KTZ31.5 | 80 mm | 1.5 kW | 14.4 m | 670 L/min | 8.5 mm | 33 kg |
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| KTZ32.2 | 80 mm | 2.2 kW | 20.4 m | 800 L/min | 8.5 mm | 34 kg |
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| KTZ33.7 (this product) | 80 mm | 3.7 kW | 29 m | 900 L/min | 8.5 mm | 60 kg |
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| KTZ35.5 | 80 mm | 5.5 kW | 32 m | 1,100 L/min | 8.5 mm | 74 kg |
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| KTZ23.7 | 50 mm | 3.7 kW | 36.5 m | 450 L/min | 8.5 mm | 60 kg |
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| KTZ43.7 | 100 mm | 3.7 kW | 18 m | 1,440 L/min | 8.5 mm | 60 kg |
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Among the 3.7 kW models, the KTZ23.7 gives more head and less flow, the KTZ43.7 more flow and less head, and the KTZ33.7 sits between them.
What's in the box
- KTZ33.7 pump with 8 m cable attached × 1
- Hose coupling (standard discharge connection) × 1
Optional accessories
- Seawater-Resistant Kit: the KTZ33.7 is on Tsurumi's official seawater model list. The kit contains galvanic anodes (with fittings and seal putty), a seawater-resistant special cast-iron impeller, a gray cast-iron hose coupling, and 304 stainless steel eye bolts (on models with steel eye bolts). For the kit-fitted version, see the KTZ33.7-SEA seawater-resistant version.
- Float switch and control panel: the KTZ33.7 has no built-in level control. For unattended running, pair it with a float switch and a motor starter or control panel with overload protection, or choose the KTZE33.7 automatic model.
- Star-delta starting: available on request; ask when ordering.
Safety and installation
- Three-phase supply only. Wiring and installation must be done by a registered electrical worker in line with local regulations, with proper grounding and a motor starter that has overload and phase-failure protection.
- Check the voltage and current on the nameplate before connecting, and check the direction of rotation after connection.
- If the built-in thermal protector trips on overheating or overcurrent, find the cause before running the pump again. Always isolate and lock out the power before inspection or servicing.
- Lift and lower the pump by its handle or eye bolt with a chain or rope. Never lift it by the power cable, and protect the cable from pulling and cuts.
- Keep the water level at or above 150 mm (W1) for continuous running, and do not run the pump dry for long periods.
- Use a strainer and do not let the pump get buried in silt. Wear is faster in abrasive or corrosive service.
- The standard model is not seawater-resistant. Do not pump liquids above 40 °C or outside pH 5–9, or flammable liquids, and do not use it in explosive atmospheres (it is not explosion-proof).
Wear parts and routine checks
- Main wear parts: impeller, suction cover, mechanical seals and oil seal. With long running in sandy water, the impeller and suction cover gradually wear and flow drops.
- Check the oil condition and level in the oil chamber regularly (turbine oil ISO VG32, 1,250 ml). If the oil is cloudy or contains water, have the shaft seals inspected promptly.
