Say goodbye to blockages! How to choose a submersible sewage pump correctly？

1. Clarify Sewage Properties: Match Anti-Clogging and Corrosion Resistance

• Solid particles and fiber content:
  • For sewage with large amounts of sediment or small stones (e.g., construction site sludge), opt for pumps with large-channel impeller designs (channel width ≥ 1.5 times the particle diameter) to prevent blockages.
  • For sewage containing easily tangled substances like long hair or cloth strips, prioritize models with cutting-type impellers (e.g., single or double-blade cutting designs), which can shred impurities before discharge.
• Corrosiveness and temperature:
  • Ordinary domestic sewage: Cast iron pump bodies are suitable (cost-effective and resistant to mild corrosion).
  • Industrial wastewater (containing acids, alkalis, or salts): Choose stainless steel (304/316) or engineering plastic (PVC/PP) materials to avoid component corrosion.
  • High-temperature sewage (e.g., food processing wastewater over 60°C): Check the pump’s temperature resistance rating (typically -10°C to 100°C; custom high-temperature motors are needed for temperatures beyond this range).

2. Determine Core Parameters: Flow Rate (Q) and Head (H)

• Flow rate (Q): The volume of sewage transported per unit time (units: m³/h or L/s).
  • Estimation method: Base it on the “sewage generation volume.” For example, for household basement drainage, if the maximum daily displacement is 5m³ and the working time is 8 hours, the flow rate should be ≥ 0.6m³/h. For municipal sewage wells, calculate using the number of residents served (each person generates ~0.2m³ of sewage daily).
  • Note: Reserve a 10%–20% margin to avoid insufficient flow during peak periods.
• Head (H): The vertical height the pump can lift sewage (unit: m). Calculate the “actual required head” as follows:
  • Formula: Actual head = vertical lifting height (vertical distance from the sewage tank bottom to the discharge outlet) + pipeline resistance loss (≈1–2m of head loss per 10 meters of pipeline; add 1–3m extra for elbows and valves).
  • Example: If the vertical height is 5m, total pipeline length is 20m, and there are 2 elbows, the actual head ≈ 5 + (20/10 × 1.5) + 2 = 5 + 3 + 2 = 10m. When purchasing, the pump’s nominal head must be ≥ the actual head, with a 5%–10% margin recommended.

3. Match Power and Motor Performance

• Protection class: Submersible sewage pumps must have an IP68 protection rating (fully dustproof and suitable for long-term underwater operation) to prevent motor short circuits from water ingress.
• Heat dissipation: Underwater operation relies on sewage for cooling. If the sewage level is too low (pump body exposed to air), poor heat dissipation may damage the motor. Thus, equip the pump with a liquid level controller (e.g., a float switch) to ensure the pump remains submerged.
• Overload protection: Choose motors with “overheat/overload protection” to automatically shut down when the pump is blocked or current is excessive, extending service life.

4. Consider Installation and Usage Scenarios

• Installation space: Submersible pumps need to fit into sewage tanks/wells. Confirm tank diameter and depth match the pump size (especially long-shaft models) to avoid installation or maintenance issues.
• Automatic control needs: For unattended scenarios (e.g., home basements, community sewage wells), select models with float switches to auto-start/stop based on liquid level (starts at upper limit, stops at lower limit). For frequent start-stop scenarios (e.g., temporary drainage), manual control is sufficient.
• Special environment requirements:
  • Flammable/explosive areas (e.g., chemical plant sewage): Use explosion-proof submersible sewage pumps (motors meeting standards like Ex dⅡBT4).
  • Low liquid level (sewage depth < 50cm): Choose “shallow submergence” models to prevent impeller blockages from bottom contact.

5. Brand and After-Sales Support

Summary