The TSURUMI KTZ411-SEA seawater-resistant version is the KTZ411 submersible dewatering pump fitted with Tsurumi's optional Seawater-Resistant Kit. The KTZ series is Tsurumi's flagship line of three-phase, cast-iron dewatering pumps (officially classed as a general construction pump). The KTZ411 has a 100 mm (4-inch) discharge and an 11 kW motor, and with a 48.5 m maximum head it is the highest-head model among the KTZ seawater-resistant versions. The kit adds galvanic anodes and a special seawater-resistant cast-iron impeller, so the pump can be used for drainage involving seawater, such as waterfront development, marine construction and aquaculture facilities.
According to Tsurumi, the Seawater-Resistant Kit provides about two years of service, depending on operating conditions. For longer-term use, check with the dealer first.
Selection note: The KTZ411-SEA is not a separate Tsurumi model; it is the KTZ411 with the Seawater-Resistant Kit. For freshwater site drainage only, the standard KTZ411 is sufficient, but the standard pump is not designed for long-term seawater use. This pump has no automatic operation, float or electrode control. Tsurumi's all-titanium/resin seawater pumps are a separate range, the TM series.
Key features
- Galvanic anodes protect the pump body: the anodes have a lower potential than the cast-iron body, so they corrode first and protect it. Tsurumi uses mainly aluminium anodes, with zinc only on the strainer stand. The anodes are consumed over time and must be replaced every two years.
- Special seawater-resistant cast-iron impeller: made from specially treated chromium cast iron with a potential slightly lower than the shaft, so the impeller corrodes slowly and protects the shaft. Its corrosive wear is about one tenth that of a conventional cast-iron impeller.
- Top-discharge, side-flow design: the motor stays cooled even when exposed to air, and the slim body fits confined spaces. With the seawater kit, keep the water level at 770 mm or above for continuous running.
- Multi-directional hose coupling: the discharge can be set vertical or inclined so the hose does not kink.
- Dual inside mechanical seals: silicon carbide (SiC) faces housed in the oil chamber, isolated from abrasion and corrosion. Tsurumi's Oil Lifter keeps the seals lubricated and cooled even when the oil drops to about one third of the normal level.
- Seal pressure relief ports and 304 stainless steel labyrinth ring: fitted to KTZ models of 7.5 kW and above, so the mechanical seals see only the sump submergence pressure.
- Built-in circle thermal protector (CTP): cuts the motor circuit directly on overheating or overcurrent.
- Anti-wicking cable entry: stops water creeping into the motor by capillary action if the cable sheath is damaged; a cable clip protects against pulling.
Applications
- Waterfront development and coastal sites: excavation and temporary drainage of seawater or brackish water
- Marine construction: dewatering during offshore and coastal works
- Aquaculture facilities: seawater pumping
This is a dewatering pump for water carrying a small amount of sand and silt (up to 10% dry matter). It is not suitable for slurry, dense sand mixtures, desilting or dredging.
Performance
The 48.5 m maximum head is the head at near-zero flow, and the 1,440 L/min (about 86.4 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. These figures are for the KTZ411 base model (50 Hz). If your duty needs more flow at a lower head, consider the 150 mm KTZ611-SEA seawater-resistant version (up to 2,440 L/min).
Technical specifications
TSURUMI KTZ411-SEA seawater-resistant version technical specifications
| Item | Specification |
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| General |
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| Model | KTZ411-SEA (KTZ411 with Seawater-Resistant Kit) |
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| Series | KTZ (general construction pump, 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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| Seawater configuration | Galvanic anodes (mainly aluminium), special seawater-resistant cast-iron impeller |
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| Hydraulic performance (KTZ411 base model, 50 Hz) |
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| Max. head (at zero flow) | 48.5 m |
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| Max. capacity (curve end point) | 1,440 L/min (86.4 m³/h) |
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| Max. solids size | 12 mm |
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| Electrical |
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| Motor output | 11 kW |
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| Motor | Dry-type induction motor, three-phase 2-pole, continuous-duty rated, insulation class F, IP68 |
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| Power supply | Three-phase (voltage as per nameplate) |
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| Speed | approx. 2,935 rpm (Tsurumi Europe 400 V 50 Hz data) |
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| Rated current | 22 A (Tsurumi Europe 400 V 50 Hz data; as per nameplate) |
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| Starting method | Direct-on-line (DOL); star-delta is available on request for the KTZ411 base model, so confirm with the dealer for the seawater-resistant version |
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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, bearings and lubrication |
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| Shaft seal | Dual inside mechanical seals, silicon carbide (SiC) faces, in oil chamber, with Oil Lifter |
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| Seal protection | Seal pressure relief ports; 304 stainless steel labyrinth ring |
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| Bearings | Shielded ball bearings |
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| Lubricant | Turbine oil ISO VG32, 760 ml |
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| Materials |
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| Impeller | Semi-open, special seawater-resistant cast iron (specially treated chromium cast iron) |
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| Suction cover | Ductile cast iron |
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| Casing, frame, motor housing | Grey cast iron |
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| Shaft | 420 stainless steel |
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| Galvanic anodes | Mainly aluminium; zinc on the strainer stand |
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| Liquid limits |
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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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| Dimensions (L × H) | 459 × 884 mm |
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| Dry weight | 133 kg (excl. galvanic anodes and cable) |
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| Min. continuous water level (C.W.L.) | 770 mm (level at which all galvanic anodes work effectively) |
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Sources: Tsurumi Seawater-Resistant Dewatering Pumps catalogue (IB115), KTZ/KTZE/KTD series catalogue (IB107), Tsurumi Hong Kong seawater-resistant pump information, and Tsurumi Europe KTZ411 data (400 V 50 Hz). Voltage and rated current of the Hong Kong supply version are as per the nameplate.
KTZ seawater-resistant models compared
The KTZ615-SEA is Jaco's seawater-resistant specification of the KTZ615, and its hydraulics are base-model data. Confirm its seawater-resistant configuration and minimum water level with Jaco before ordering.
Seawater-Resistant Kit contents
According to Tsurumi, the Seawater-Resistant Kit includes:
- Galvanic anodes (with fittings and seal putty)
- Special seawater-resistant cast-iron impeller
- 304 stainless steel eye bolts (only for models fitted with steel eye bolts)
The grey cast-iron hose coupling in the kit applies to KTZ 3.7 kW models only and is not part of the KTZ411 kit. Please confirm the exact supply configuration when ordering.
Optional accessories
- Float switch and motor starter / control panel: the pump has no built-in level control, so unattended operation needs a float switch and a control panel with overload protection.
- Replacement galvanic anodes (every two years) and special seawater-resistant cast-iron impeller; ask the dealer for part numbers.
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 has overload and phase-loss protection. Check the voltage and current on the nameplate before connecting.
- Check the direction of rotation after connection.
- If the built-in thermal protector trips, find the cause of the overheating or overcurrent before running again. Isolate and lock out the power before any inspection or service.
- Never lift or lower the pump by its cable; use the eye bolt or handle with a chain or rope. The pump weighs 133 kg dry, so lifting equipment is required for handling and lowering.
- Keep the water level at 770 mm or above for continuous running. Below this level, parts that are not submerged may corrode.
- Stand the pump on a stable base so it does not get buried in silt. Expect faster wear in sandy or corrosive service.
- Do not use with flammable liquids or in flammable or explosive atmospheres; the pump is not explosion-proof. Liquid temperature must not exceed 40 °C, and pH must be within 5–9.
Wear parts and routine checks
- Galvanic anodes: consumed over time; replace every two years.
- Special seawater-resistant cast-iron impeller: corrodes slowly to protect the shaft; replace every few years, up to 10 years, depending on operating conditions.
- Mechanical seals and suction cover: wear gradually with long running in sandy water.
- Check the oil in the oil chamber regularly (turbine oil ISO VG32, 760 ml). If the oil is cloudy or contains water, have the shaft seals inspected promptly.
