What is a sewage pump? The working principle and application scenarios of sewage pumps

What is a sewage pump?

A sewage pump is a type of pump designed specifically for conveying wastewater containing impurities (such as feces, tissues, and sludge). Unlike ordinary water pumps, its key features are its ability to handle high-viscosity liquids containing solid particles (typically ≤50mm in diameter) and its anti-clogging properties. Based on their structure, they can be divided into two categories:

1. Centrifugal sewage pumps: These pumps use the rotating impeller to generate centrifugal force and are suitable for handling wastewater with smaller particles (such as household wastewater).

2. Cutter sewage pumps: These pumps use internal rotating blades to pulverize solids and are suitable for handling wastewater containing impurities such as fibers and sanitary napkins (e.g., in public toilets).

How does a sewage pump work?

Its operating principle can be divided into three steps:

1. Sewage Collection: Sewage enters the pump tank through the inlet pipe. When the liquid level reaches a preset height (usually 2/3 of the way up the tank), a float switch or sensor triggers the pump to start.

2. Pressurized Discharge: The high-speed rotation of the impeller (approximately 2900 rpm) generates pressure, pushing the sewage into a vertical or horizontal drain pipe. Some high-end models feature dual pumps operating alternately to handle peak flow rates.

3. Backflow Protection: A check valve prevents sewage from flowing back, ensuring system hygiene and safety.

Application Scenarios and Selection Recommendations

Core application scenarios for sewage pumps include:

1. Basement drainage: For basement bathrooms, garage laundry rooms, and other applications, a silent pump (≤45dB) with a cutter function is recommended.

2. Commercial buildings: For public facilities such as hotels and shopping malls, flow rate requirements (recommended ≥30m³/h) and durability are important. Stainless steel pumps are recommended.

3. Municipal engineering: Subway stations and underpasses require drainage systems with an IP68 waterproof rating and dual-pump redundancy.

Notes when selecting a pump:

- Flow rate calculation: Estimate based on the number of users. For example, for a household, 0.15m³ of sewage per person per day is used (refer to the "Design Standard for Building Water Supply and Drainage" GB50015).

- Lift requirement: Vertical lift height + horizontal pipe length × 10% (friction loss).

Maintenance and Troubleshooting

Regularly cleaning the pump's interior (recommended every three months) and inspecting the seals can extend its service life. Common faults, such as frequent starts and stops, may indicate a stuck float, requiring manual reset.

The above analysis demonstrates that sewage pumps are critical components of modern drainage systems, and their technical specifications and suitability for specific applications directly impact their effectiveness.