What Is a Dry-Type Sewage Pump?
A dry-type sewage pump is a specialized pump designed to transport sewage containing solid particles, fibers, sludge, and other impurities. Its core rotating components (such as the motor and bearings) do not come into direct contact with sewage. Its design features a separation structure that isolates the motor from the sewage medium, preventing the motor from corrosion or damage caused by sewage—making it suitable for various harsh sewage environments.
I. Core Structure and Working Principle
The core structure of a dry-type sewage pump lies in “dry-wet separation,” mainly consisting of the following parts:
- Pump body: In direct contact with sewage, it contains an internal impeller. As the impeller rotates, it generates centrifugal force to suck in and discharge sewage.
- Motor: Serving as the power source, it connects to the pump body via a transmission structure (e.g., a coupling). The motor is completely isolated from sewage to prevent moisture damage, corrosion, or entanglement by impurities.
- Sealing device: At the connection between the pump body and the motor, mechanical seals or packing seals are typically used to prevent sewage from leaking into the motor compartment.
II. Main Characteristics
- Strong corrosion resistance: The pump body is often made of cast iron, stainless steel, or engineering plastics, enabling it to resist sewage containing corrosive components such as acids and alkalis.
- Wide applicability: It can transport sewage with solid particles (e.g., sediment, gravel) and fibers (e.g., cloth strips, hair), making it ideal for municipal sewage treatment, industrial wastewater discharge, basement drainage, and more.
- Easy maintenance: Since the motor does not contact sewage, failure rates are low. Additionally, maintenance requires no direct contact with sewage, simplifying operations.
- Flexible installation: It can be installed in a fixed configuration (e.g., in a pump pit) or a mobile setup (e.g., portable sewage pumps) based on needs.
III. Differences from Wet-Type Sewage Pumps
| Comparison Items | Dry-Type Sewage Pump | Wet-Type Sewage Pump (e.g., submersible pump) |
|---|---|---|
| Motor position | Isolated from sewage, typically positioned above the water surface | Submerged in sewage, in direct contact with sewage |
| Sealing requirements | High demands on sealing devices (to prevent leakage) | Relies on waterproof sealing of the motor housing |
| Applicable scenarios | Large-scale sewage treatment, high-impurity sewage applications | Small-scale drainage, shallow water operations |
| Maintenance difficulty | Lower (motor is easy to service) | Higher (water leakage easily damages the motor) |
IV. Typical Application Scenarios
- Sewage lifting processes in urban wastewater treatment plants;
- Discharge of industrial wastewater (including waste residues and chemicals) in factory workshops;
- Removal of standing water in basements and foundation pits during construction;
- Conveying in rural domestic sewage centralized treatment systems.
With its structural advantages, dry-type sewage pumps play a key role in sewage transportation, particularly in scenarios requiring high equipment durability and easy maintenance.