The TSURUMI HS3.75S 110V is a portable dewatering pump from Tsurumi's HS series (official classification: submersible pumps > portable dewatering pumps), supplied here in the single-phase 110V 50Hz version. It has an 80 mm (3-inch) discharge and a 0.75 kW single-phase capacitor-run motor, with a urethane rubber semi-vortex impeller and a sintered-alloy agitator. It passes solids up to 7 mm and weighs 16.8 kg without the cable, so one person can carry it to site water, basements and flooded areas for temporary drainage.
"110V" is a supply version, not part of Tsurumi's model code: the factory model is HS3.75S in both cases, and Tsurumi Europe and Tsurumi UK offer it in single-phase 110V and 230V versions. The 110V version must run on a 110V 50Hz supply, which on construction sites usually comes from an isolating transformer.
Selection note: the HS3.75S is a manual model with no float switch, so it is switched on and off by hand. For automatic start/stop by water level, choose the HSZ3.75S 110V automatic model, which has the same performance. For a 230V supply, choose the HS3.75S (230V). HS series pumps are dewatering pumps, not sewage or slurry pumps: for settled sand, mud or bentonite, use the HSD2.55S slurry pump. If you need more flow at a lower head, consider the HS3.75SL (580 L/min max. capacity, 10.8 m max. head).
Key features
- Shaft-mounted agitator prevents air lock: a sintered-alloy agitator on the shaft stops the air lock that vortex and semi-vortex pumps are prone to.
- Abrasion-resistant wear parts: parts exposed to wear are made of abrasion-resistant material, which Tsurumi says gives durability equivalent to its three-phase drainage pumps.
- Side discharge with spiral casing: solids pass through more smoothly, and the external side outlet helps draw solids in.
- Double inside mechanical seals: silicon carbide (SiC) faces running in an oil chamber, with Tsurumi's own Oil Lifter, which keeps the seal faces lubricated and cooled even when the oil drops to one third of its normal level.
- NBR V-ring dust seal: fitted on models of 0.55 kW and above, including this one.
- 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 sheath is damaged or the cable end is submerged, and prevents condensation inside the motor housing. A cable clip protects against tugging.
- Resin stand: prevents the pump from scratching the floor.
Applications
- Construction sites: excavations, trenches and temporary site water
- Buildings and facilities: water in basements, plant rooms and lift pits
- Storms and flooding: emergency drainage
- Maintenance works: temporary pumping during drain, manhole and tank maintenance
The pump is suited to water carrying a small amount of solids (up to 7 mm). It is not suitable for raw sewage, fibrous liquids, slurry, seawater or chemicals.
Performance
The 18 m maximum head is the head at near-zero flow, and the 300 L/min (about 18 m³/h) maximum capacity is the end point of the 50 Hz performance curve. The two do not occur together: actual flow falls as total head (static head plus hose friction loss) rises, so select the pump from the performance curve using your site's total head. Tsurumi UK lists the same performance for the 110V and 230V versions (310 L/min max. capacity, 18 m max. head).
Technical specifications
TSURUMI HS3.75S 110V technical specifications (50 Hz)
| Item | Specification |
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| General |
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| Model | HS3.75S (110V supply version) |
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| Type | Portable dewatering pump (submersible, manual) |
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| Discharge bore | 80 mm (3 in) |
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| Discharge connection | Hose coupling (standard); male threaded coupling on special request |
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| Hydraulic performance |
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| Max. head (at zero flow) | 18 m |
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| Max. capacity (curve end point) | 300 L/min (approx. 18 m³/h) |
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| Max. solids passage | 7 mm |
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| Impeller | Semi-vortex, urethane rubber |
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| Agitator | Sintered alloy |
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| Electrical |
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| Motor output | 0.75 kW |
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| Power supply | Single-phase 110V 50Hz |
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| Motor | Dry-type induction motor, 2-pole, insulation class E, continuous-duty rated |
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| Starting method | Capacitor run |
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| Synchronous speed | 3,000 min⁻¹ (50 Hz) |
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| Motor protection | Built-in circle thermal protector (CTP) |
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| Cable | 5 m PVC cable |
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| Seals and materials |
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| Shaft seal | Double inside mechanical seals, silicon carbide (SiC) faces, oil-lubricated, with Oil Lifter |
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| Lubricant | Turbine oil ISO VG32, 160 ml |
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| V-ring | Nitrile rubber (NBR) |
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| Pump casing | Ductile cast iron |
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| Shaft | 403 stainless steel |
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| Stand | Resin |
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| Dimensions and weight |
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| Dry weight (excl. cable) | 16.8 kg |
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| Dimensions (L × W × H) | 285 × 184 × 394 mm |
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| Discharge centre height | 218 mm |
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| Min. water level for continuous running | 90 mm |
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| Liquid limits (Tsurumi Europe data) |
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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 | 20 m |
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Sources: Tsurumi single-phase portable pumps catalogue (IB101), Tsurumi Hong Kong and Tsurumi Global HS product pages, and Tsurumi Europe / Tsurumi UK HS series data (50 Hz). Tsurumi Hong Kong notes that published data may differ from the actual product, so obtain the delivery specification sheet before use. Voltage and rated current are as per the nameplate.
HS series manual models compared
Tsurumi HS series portable dewatering pumps compared (50 Hz)
| Model | Discharge | Power | Max. head | Max. capacity | Max. solids | Dry weight |
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| HS2.4S 110V | 50 mm | 0.4 kW | 12 m | 200 L/min | 7 mm | 11.3 kg |
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| HS2.75S 110V | 50 mm | 0.75 kW | 18 m | 230 L/min | 7 mm | 16.4 kg |
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| HS3.75S 110V (this product) | 80 mm | 0.75 kW | 18 m | 300 L/min | 7 mm | 16.8 kg |
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| HS3.75SL | 80 mm | 0.75 kW | 10.8 m | 580 L/min | 7 mm | 19.6 kg |
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Optional accessories
- 80 mm (3-inch) discharge hose for the standard hose coupling.
- Male threaded coupling for pipe connection, available from the factory on special request.
- 110V site isolating transformer with a 110V 50Hz output rated for the motor.
- Float switch: Tsurumi Europe offers a short float for single-phase pumps that can be fitted to the HS series for automatic operation; check availability with the Hong Kong agent. For a factory automatic model, choose the HSZ3.75S 110V.
- Oil leakage sensor: Tsurumi Europe offers a seal-oil sensor for the HS3.75S, which needs a separate relay; check availability with the Hong Kong agent.
Safety and installation
- Connect this pump only to a single-phase 110V 50Hz supply. Never connect it to 230V, and never run a 230V version on 110V.
- Use a correctly rated, earthed supply; an outlet with earth-leakage (RCD) protection is recommended. Electrical connection must be made by a registered electrical worker in line with local regulations.
- The built-in thermal protector (CTP) is a safeguard only. Do not let the pump run dry for long periods, and keep at least 90 mm of water for continuous running.
- Lift and lower the pump by its handle, never by the power cable. Protect the cable from damage; a damaged cable must be replaced or repaired before use.
- Stand the pump on firm ground or a raised platform so it does not sink into silt.
- Do not use it in flammable or explosive atmospheres or with flammable or corrosive liquids, and stay within 0–40 °C liquid temperature, pH 5–9 and 20 m maximum submersion depth.
Wear parts and routine checks
- Main wear parts: impeller, agitator, mechanical seals and V-ring. With long running in sandy water the impeller gradually wears and flow drops.
- Isolate the power before inspection or servicing. Check and change the seal oil (turbine oil ISO VG32, 160 ml) periodically; if the oil is cloudy or contains water, have the shaft seals inspected promptly. The Oil Lifter only maintains lubrication down to one third of the normal oil level, so do not delay topping up.
