The TSURUMI 50B2.75H is the high-head model in Tsurumi's B series of non-clog sewage pumps (channel impeller). It has a 50 mm discharge and a 0.75 kW 2-pole three-phase motor. The anti-clogging semi-open single-channel impeller, grey cast-iron casing, impeller and motor frame, and 420 stainless-steel shaft make it suited to building sewage sumps and to sewage and wastewater carrying solids and fibrous matter. At 50 Hz it delivers up to 15.2 m of head and up to 360 L/min (21.6 m³/h).
Selection note: Tsurumi offers three 50 mm, 0.75 kW B-series models. This 50B2.75H is the three-phase high-head version (15.2 m / 360 L/min). The 50B2.75 is the three-phase standard version, with lower head but more flow (12 m / 435 L/min). The 50B2.75S is the single-phase version and shares the 50B2.75H performance curve. B-series pumps are non-clog sewage pumps, not slurry pumps, and are not suitable for dense sludge or sand slurry.
Key features
- Non-clog channel impeller: a semi-open single-channel design that minimises trouble from clogged solids and fibrous matter, with a solids passage of about 20 mm.
- High-head design: compared with the standard 50B2.75 of the same bore and output, maximum head rises from 12 m to 15.2 m, suiting deeper sumps or longer discharge lines.
- Dual inside mechanical seals: silicon carbide (SiC) faces running in an oil chamber, with Tsurumi's original Oil Lifter, which keeps the seal faces lubricated even when the oil drops to about one third of the normal level.
- Built-in circle thermal protector (CTP): cuts the motor circuit directly on overheating or overcurrent.
- Anti-wicking cable entry: stops water creeping along a damaged or submerged cable into the motor and prevents condensation inside the motor.
- Continuous-duty motor: dry-type induction motor rated IP68, with shielded ball bearings.
- Optional guide-rail installation: with the TOS50B2.75H guide rail fitting, the pump can be lifted out for service without entering the sump.
Applications
- Buildings and commercial properties: sewage sumps and basement sewage pits
- Sewage and wastewater: transfer of sewage and wastewater containing solids and fibrous matter
- Sewage treatment facilities: sump transfer duty
- Factories and plants: wastewater pit discharge (liquid at 0–40 °C, pH 5–9)
The standard model is not intended for seawater, liquids above 40 °C, or flammable or strongly corrosive liquids, and it is not an explosion-proof pump.
Performance
The 15.2 m maximum head is the head at near-zero flow, and the 360 L/min (21.6 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 pipe friction loss) rises. Select the pump from the performance curve using your site's total head. For lower total head and more flow, consider the standard 50B2.75 (435 L/min); for a larger bore and more flow, consider the 80B21.5 (80 mm, 1,000 L/min).
Technical specifications
TSURUMI 50B2.75H technical specifications (50 Hz)
| Item | Specification |
|---|
| General |
|---|
| Model | 50B2.75H |
|---|
| Series | B series non-clog sewage pump (high-head type) |
|---|
| Discharge bore | 50 mm |
|---|
| Discharge connection | Threaded oval flange (threaded JIS 10K flange on the guide-rail version) |
|---|
| Hydraulic performance |
|---|
| Max. head (at zero flow) | 15.2 m |
|---|
| Max. capacity (curve end point) | 360 L/min (21.6 m³/h) |
|---|
| Solids passage | approx. 20 mm (0.79 in) |
|---|
| Impeller | Semi-open single-channel, grey cast iron |
|---|
| Electrical |
|---|
| Motor output | 0.75 kW |
|---|
| Motor | 2-pole dry-type induction motor, continuous duty, IP68 |
|---|
| Synchronous speed | 3,000 min⁻¹ (50 Hz) |
|---|
| Power supply | 3-phase 50 Hz (voltage as per nameplate) |
|---|
| Starting method | Direct-on-line (DOL) |
|---|
| Motor protection | Built-in circle thermal protector (CTP) |
|---|
| Cable | 6 m, PVC |
|---|
| Seals and bearings |
|---|
| Shaft seal | Dual inside mechanical seals, silicon carbide (SiC) faces, oil-lubricated, with Oil Lifter |
|---|
| Oil seal | Single NBR oil seal |
|---|
| Lubricant | Turbine oil ISO VG32, 440 ml |
|---|
| Bearings | Shielded ball bearings |
|---|
| Materials |
|---|
| Casing, impeller, suction cover | Grey cast iron |
|---|
| Motor frame | Grey cast iron |
|---|
| Shaft | 420 stainless steel |
|---|
| Liquid limits |
|---|
| Liquid | Sewage and wastewater |
|---|
| Liquid temperature | 0–40 °C |
|---|
| pH | 5–9 |
|---|
| Dimensions and weight |
|---|
| Dry weight (excl. cable) | 24 kg (guide-rail version 23 kg, excl. duckfoot bend) |
|---|
| Dimensions (L × W × H) | 405 × 250 × 415 mm |
|---|
| TOS50B2.75H guide-rail version (L × W × H) | 621 × 250 × 458 mm |
|---|
| Lowest running water level | 145 mm |
|---|
Sources: Tsurumi B-series catalogue (IA100), Tsurumi Europe B-series data (50 Hz) and Tsurumi Canada (solids passage). Voltage and rated current of the Hong Kong supply version are as per the nameplate and confirmation from the Hong Kong agent.
B series comparison: 50–80 mm models
Tsurumi B series non-clog sewage pump comparison (50 Hz)
| Model | Discharge | Power | Supply | Max. head | Max. capacity |
|---|
| 50B2.4 | 50 mm | 0.4 kW | 3-phase | 9 m | 263 L/min |
|---|
| 50B2.75 | 50 mm | 0.75 kW | 3-phase | 12 m | 435 L/min |
|---|
| 50B2.75H (this product) | 50 mm | 0.75 kW | 3-phase | 15.2 m | 360 L/min |
|---|
| 50B2.75S | 50 mm | 0.75 kW | 1-phase | Same performance curve as 50B2.75H |
|---|
| 80B21.5 | 80 mm | 1.5 kW | 3-phase | 16.9 m | 1,000 L/min |
|---|
Optional accessories
- TOS50B2.75H guide rail fitting: includes the duckfoot bend, guide support with bolts and nuts, guide hook, 5 m lifting chain with shackles and a JIS 10K flange. Guide pipes are not supplied and must be provided on site.
- Float switches: the MC heavy-duty float switch (with shock absorber, for liquids with suspended solids and scum) or the MT float switch with integrated counterweight, used together with an external control panel.
- Control panel: three-phase pumps must be connected through a control panel providing overload protection and phase checking.
- Discharge piping: the guide-rail version uses a JIS 10K flange, so specify a JIS 10K mating flange for the pipework.
Safety and installation
- Installation and wiring must be carried out by a registered electrical worker in line with local regulations. Earth the pump correctly and fit overload and earth-leakage protection in the control panel.
- On three-phase pumps, check that the rotation is correct before putting the pump into service.
- After the built-in CTP trips, the motor may restart automatically once it cools. Always isolate the power before inspection or servicing.
- Keep the liquid above the lowest running water level (145 mm) and avoid prolonged dry running.
- Lift the pump by its handle or a lifting chain, never by the power cable (dry weight about 24 kg).
- Never let the cable end be submerged and never cut or damage the cable sheath. The anti-wicking cable entry is a safeguard only.
- Do not touch the pump or put your hands near the suction while it is energised. Sewage sumps are confined spaces: follow confined-space and gas (such as H₂S) precautions before entry. A guide-rail installation reduces the need to enter the sump.
- The standard model is not seawater-resistant or rated for hot liquids. Seawater-resistant (with sacrificial anode) and high-temperature (up to 80 °C) versions are special-order items.
Wear parts and routine checks
- Main wear parts: mechanical seals, oil seal and impeller.
- Check the oil in the oil chamber regularly and replace it as needed (turbine oil ISO VG32, 440 ml) to protect the mechanical seals. If the oil is cloudy or contains water, have the shaft seals inspected promptly.
- If flow drops noticeably, check the impeller for wear or entangled fibrous matter.
