Self-Cleaning Filter with Bag Filter in Series

Product Overview

The Fully Automatic Scraper Self-Cleaning Filter is available in two configurations: internal-scraper and external-scraper types. The system mainly consists of a geared motor, filter housing, filter screen, scraper cleaning assembly, differential-pressure control system, electrical control cabinet, and drain valve.

Unlike backwashing self-cleaning water filters, scraper filters are suitable not only for water filtration but also for the continuous filtration of viscous process fluids such as solvents, acidic and alkaline solutions, polymers, coatings, and similar materials.

The filtration rating ranges from 30 to 1,500 μm, and specially configured systems can handle fluids with viscosities of up to 800,000 cP. The equipment is widely used in water treatment, petrochemical, metallurgy, power generation, fine chemicals, coatings, inks, papermaking, food and beverage, pharmaceutical, and metal-processing industries.

The electric scraper filter operates automatically and provides high filtration accuracy with stable and reliable performance. It is an effective alternative to conventional manually cleaned filters and systems using disposable filter media. In many applications, it can also replace traditional cartridge filters, bag filters, basket strainers, vibrating screens, and similar filtration equipment.

Working Principle

The process fluid enters the filter through the inlet and passes through the filter screen. Solid particles larger than the screen openings are retained on the filtration surface.

As filtration continues, contaminants gradually accumulate on the filter screen, causing the differential pressure across the filter to increase.

When the differential pressure reaches the preset value, the differential-pressure control system sends a signal to start the geared motor. The motor drives the scraper assembly to rotate along the surface of the filter element, removing accumulated contaminants and restoring the effective filtration area.

At the same time, the bottom drain valve opens automatically to discharge the collected impurities.

After the contaminants are removed, the differential pressure returns to the normal operating range and continuous filtration resumes without the need to stop the main process.

General Specifications

• Operating flow rate: 50–350 m³/h
  Custom designs are available for higher or lower flow requirements
• Working pressure: 0.2–1.0 MPa
• Filtration area: 3,000–20,000 cm²
• Recommended fluid viscosity range: 3,000–100,000 cP
• Inlet / outlet size: DN50–DN200
• Working temperature: ≤230°C
  Custom designs are available for higher-temperature applications
• Control power supply: 24 V DC
  10–24 V DC options available according to requirements
• Motor power: 0.37–0.75 kW, 50 Hz
• Rated operating voltage: 220 V / 380 V
• Rated current: 1.5–2.0 A

Product Features and Advantages

The scraper assembly is designed with an optimized arrangement and cleaning angle. Driven by the geared motor, the scraper continuously removes accumulated contaminants from the filter element to maintain stable filtration performance.

The cleaning mechanism consists of scrapers and spring-loaded components. The spring pressure is carefully selected to maintain effective contact with the filtration surface while minimizing wear on the filter screen.

The spring-loaded design also compensates for gradual scraper wear, helping extend the service life of the scraper assembly.

The filter uses a wedge-wire element constructed from V-shaped stainless-steel wires and stainless-steel support rods.

The smooth surface of the wedge-wire element serves as the filtration surface, while precisely controlled slot openings provide consistent filtration performance.

Compared with conventional filter elements, the special wedge-wire structure offers several advantages:

• Reduced risk of clogging
• Easy mechanical cleaning
• Long service life
• Stable filtration accuracy
• Low discharge volume
• Reduced loss of valuable process material
• Continuous operation with minimal manual intervention

Applications

Applicable Industries

• Water treatment
• Pulp and paper
• Petrochemical processing
• Biopharmaceuticals
• Coatings
• Printing inks
• Oils and fats
• Food and beverage processing

Typical Process Fluids

The scraper self-cleaning filter can be used for a wide variety of fluids, including:

• Wax
• Kerosene
• Monomers
• Polymers
• Water
• Citric acid solutions
• Fermentation liquids
• Protein solutions
• Soap
• Sorbitol
• Wet-end additives
• Adhesives
• Printing inks
• Pigments
• Coatings
• Resins
• Rubber-related process fluids
• Ethanol
• Chocolate
• Confectionery products
• Edible oils
• High-temperature oils
• Fruit juices
• Coolants
• Diesel fuel