Self-cleaning filters — also called automatic backwash filters or automatic self-cleaning strainers — are essential components in industrial water circuits ranging from cooling water systems and boiler feedwater to irrigation and process water. Unlike cartridge or bag filters that require manual element replacement, self-cleaning filters backwash automatically, making them ideal for continuous, high-volume applications.
This buyer’s guide walks through the key parameters you need to specify before purchasing.
1. Define Your Flow Rate and Pressure Requirements
Start with your maximum design flow rate (m³/h) and the available inlet pressure. Self-cleaning filters have a pressure drop across the element — typically 0.03–0.10 bar during normal operation. Your system must maintain sufficient pressure for the backwash cycle to operate effectively, usually a minimum differential of 0.07 bar.
2. Select the Filtration Grade (Mesh Size)
Filtration grade is measured in microns (μm) or mesh. Common industrial grades include:
- 100–500 μm: Cooling tower make-up water, irrigation, general process water — removes sediment, rust, and debris
- 50–100 μm: Chiller and heat exchanger protection — prevents tube fouling
- 10–50 μm: Precision cooling circuits, spray nozzle protection
- Below 10 μm: Pre-filtration ahead of RO or ultrafiltration membranes
Note: Finer meshes require more frequent backwash cycles and higher differential pressure for effective cleaning.
3. Choose the Right Body Material
Material selection depends on your water chemistry and operating temperature:
- Carbon Steel + Epoxy Coating: Cost-effective for clean freshwater applications
- Stainless Steel 304/316L: Ideal for mildly corrosive water, seawater pre-treatment, food & beverage
- Duplex Stainless Steel: High-chloride environments, offshore applications
- FRP (Fiberglass Reinforced Plastic): Chemical resistance, lightweight, suitable for acids/alkalis
4. Backwash Mechanism: Disc vs. Screen vs. Brush
Three main backwash technologies are available:
- Suction Backwash (Scanner Type): A rotating suction arm sweeps the filter screen during backwash. Low water consumption, suitable for moderate fouling loads. Most common in cooling water applications.
- Brush & Flush Backwash: Motorized brushes mechanically scrub the screen while flushing. Better for sticky or biological fouling (e.g., algae in cooling towers).
- Disc Filter (Stack Disc): Uses grooved plastic discs as the filter medium. Very effective against organic matter and algae, easy to clean.
5. Control & Automation Options
Modern self-cleaning filters should offer:
- Differential pressure-triggered backwash (automatic, set-point adjustable)
- Timer-based backwash as backup
- 4-20 mA or RS485 Modbus output for SCADA integration
- Local HMI panel with fault alarm relay
Yaotong Self-Cleaning Filter Range
Wuxi Yaotong manufactures a full range of automatic self-cleaning filters from DN25 to DN600, with filtration grades from 10 to 3000 μm and flow rates up to 2,000 m³/h. All units feature stainless steel screen elements, PLC control panels, and can be customized for high-temperature or corrosive service.
Have a specific application? Send us your flow rate, pressure, and water quality parameters and our engineers will recommend the right model and prepare a technical quotation within 24 hours.
