Externally Fed Rotary Drum Screens and Strainers

For the removal of suspended solids from process and wastewater streams

Externally-fed Rotary Drum Screen

American made since 1980, this stainless steel wedge wire screen is self-cleaning by nature due to constant back washing.  This often allows for only intermittent use of the spray bar cleaning system, reducing water usage. Not well suited for fine screening of high flows, but the use of the doctor blade system makes this mechanical screen well suited when oils and grease are present. Sized based on peak flow, solids and fats, oils, grease loadings in the wastewater/process water, these units can be configured with a variety of piping scenarios, overall dimensions and slot openings. Bypass configurations allow for bypass of overflow when upset conditions occur.

Externally Fed Screens

Externally-fed Rotary Drum Screens are individually designed to meet the client’s needs with regard to headbox configuration, inlets/outlets, height, width, pumped or gravity flow, etc.
All externally fed screens are equipped with overflow bypass provisions, located to suit the client’s needs, eliminating overflow concerns.
All stainless steel construction featuring a fully chassis legs, pans, and other extraneous parts with no hidden add-on costs.
The wedge wire screen with variable slot opening provides solids removal based on client’s specific particle size distribution.
Each system is equipped with an integral sump which can be oversized and/or conformed to meet design and potential upset conditions.
Externally fed screens are equipped with high pressure, CIPable spray manifold systems which can be run automatically or with manual operation.
For Food Applications: USDA approved, with a design that allows for the entire screen to be CIPed.
Screening systems are offered with a wide range of electrical control panel options, from basic to sophisticated control circuitry.
Additionally, spares and replacement parts are available, assuring years of uninterrupted service.


  • Screen cylinder of heliicalwound wedge wire
  • Screen slot openings 0.005to 0.250for a variety of applications
  • Screen assembly complete with internal support(s), tie rods, end rings, hub and shafts
  • Influent headbox designs to handle pumped or gravity flow feed, complete with flow dampening weir(s)
  • Influent overflow bypass piping

  • Chassis designs for open or enclosed filtrate discharge
  • Internal CIP manifold assembly with sprays designed for high pressure cleaning
  • Solids discharge blade assembly of UHMW construction
  • Shaft mounted, variable speed drives
  • All metal components of stainless steel construction

Externally fed rotary drum screens

Externally fed rotary drum screens are used in wastewater treatment processes and other industrial applications to separate solid materials from liquid. These screens consist of a rotating drum with perforations or slots on its surface. Here’s what they do:

  1. Separation of Solids from Liquid: The primary function of externally fed rotary drum screens is to separate solid particles from a liquid stream. This is particularly important in wastewater treatment plants where the goal is to remove solid contaminants from sewage or industrial wastewater before it can be discharged or further treated.

  2. Screening and Filtration: As the liquid flows into the drum screen, the solid particles and debris are captured on the surface of the rotating drum due to the perforations or slots. The size of these openings can be customized based on the specific requirements of the application. Larger openings allow larger particles to pass through, while smaller openings capture finer solids.

  3. Continuous Operation: One of the advantages of externally fed rotary drum screens is that they can operate continuously. The rotation of the drum ensures a continuous screening process, making them suitable for applications where a constant flow of liquid needs to be processed.

  4. Self-Cleaning Mechanism: To prevent clogging and maintain efficient operation, many rotary drum screens are equipped with a self-cleaning mechanism. This mechanism typically involves brushes or spray nozzles that clean the drum’s surface as it rotates, dislodging and removing accumulated solids.

  5. Efficient Solids Removal: Rotary drum screens are known for their efficiency in removing solids from liquid streams. They are often used as a preliminary treatment step in wastewater treatment plants to protect downstream processes and equipment from damage or contamination.

  6. Variability in Design: Externally fed rotary drum screens come in various designs, including different drum configurations, materials, and sizes. The choice of design depends on factors such as the type of solids being removed, the flow rate of the liquid, and the specific requirements of the application.

Overall, externally fed rotary drum screens play a crucial role in the treatment and purification of liquid streams by effectively separating solid contaminants, improving water quality, and protecting downstream processes and equipment.

Dontech Industries Inc, specializing in custom fabrication of externally fed rotary drum screens, follows a structured process to design and manufacture these screens according to the specific requirements of our customers. Here’s an overview of how we make externally fed rotary drum screens:

  1. Initial Consultation:

    • The process begins with an initial consultation between Dontech Industries Inc and the client. During this consultation, the client discusses their specific needs and requirements for the externally fed rotary drum screen. This includes details such as the desired screen size, material to be screened, flow rate, type of solids to be removed, and any special features required.
  2. Design and Engineering:

    • Dontech Industries Inc’s engineering team then takes the client’s specifications and begins the design process. They use specialized software and expertise to create a customized design for the rotary drum screen. This design includes the size and shape of the drum, the configuration of perforations or slots, the materials used, and any additional features like self-cleaning mechanisms.
  3. Material Selection:

    • The choice of materials is crucial in designing a custom rotary drum screen. Dontech Industries Inc selects materials that are corrosion-resistant, durable, and suitable for the specific application. Common materials used include stainless steel, carbon steel, and various plastic materials.
  4. Fabrication and Manufacturing:

    • Once the design is finalized and materials are selected, Dontech Industries Inc proceeds with the fabrication and manufacturing of the rotary drum screen. Skilled technicians and advanced machinery are used to construct the drum, perforations, support structure, and any other components.
  5. Custom Features and Modifications:

    • Dontech Industries Inc can incorporate custom features based on the client’s requirements. This might include adjusting the size and spacing of perforations to match the particle size distribution of the solids being removed. They can also add self-cleaning brushes, spray nozzles, or other mechanisms to improve screen efficiency and prevent clogging.
  6. Quality Control and Testing:

    • Quality control is a critical step in the manufacturing process. Dontech Industries Inc would conduct rigorous testing to ensure that the custom rotary drum screen meets the specified performance criteria. This may involve flow rate tests, solids removal efficiency tests, and durability assessments.
  7. Delivery and Installation:

    • Once the custom rotary drum screen is manufactured and passes quality control tests, it is prepared for delivery to the client’s location. Dontech Industries Inc can provide installation services to ensure proper setup and integration into the client’s wastewater treatment system or industrial process.
  8. Training and Support:

    • Dontech Industries Inc may offer training and ongoing support to the client’s operators and maintenance personnel to ensure the efficient operation and maintenance of the custom-made rotary drum screen.
  9. Customization Documentation:

    • A comprehensive documentation package, including drawings, specifications, and maintenance guidelines, is typically provided to the client for reference and future maintenance.

By following these steps, Dontech Industries Inc can design, manufacture, and deliver externally fed rotary drum screens that precisely meet the unique needs of their clients’ wastewater treatment or industrial processes. Customization ensures optimal performance and efficiency in the specific application.

Dontech Industries History

Founded in 1980, Dontech Industries, Inc. offers decades of engineering and design of screens, screening systems, belt presses and solids conveyance systems.

With its own team of experienced machine operators/welders each screen is individually constructed and sized based on the client’s needs. This professional team allows for ease of construction of equipment that is unique in shape, size, or other design considerations.

Offering experience on both the industrial and municipal markets, our professionals have the knowledge that allows all pertinent design questions to be addressed, assuring the final screen meets the design application and specifications.

We're Ready to Start a Customized Build for You!