Friction Washers

Rotajet Plastic Friction Washers are used to wash highly contaminated plastic films, PET, and rigid bottle granulate. Normally, the Rotajet friction washers are positioned after wet granulation and prior to Rotajet float sink tanks.

The Rotajet friction washer consists of a high-speed rotor mounted by two bearings, top and bottom, with a full hexagonal screen around the rotor. The rotor and screen are housed in a robustly manufactured frame that is mounted on an incline.

The liquid and plastic granulate mix from the wet granulator is fed into the base of the Rotajet friction washer. High-speed rotating paddles force the liquid and granulate mix to the outside screen, forcing the liquid and contaminants to pass through the screen. The plastic granulate is driven up the screen at high speed to the material outlet at the top. 

The screen is fitted with outside spray bars to keep clean and free of plastic dust and paper pulp. For highly contaminated material, a pneumatic screen scraper can be fitted to scrape the screens clean and is used in conjunction with the spray bars.

The Rotajet friction washers are manufactured with easy-to-replace D2 paddles, and quick-release internal screen.

Operation of Friction Washers​

As producers of recycled plastics, there are really two variables that are paramount in your mind. The amount produced and the cost of achieving it. It is important to understand therefore what energy is being used to clean your material so the simplest and most cost-efficient solutions are chosen
To wash any product three types of energy can be used to remove contaminants from their surface: chemical energy, mechanical energy, and thermal energy. This is no different when washing plastics during the recycling process.
The design of our friction washers allows us to fine-tune the relationship between these forms of energy so we can optimize your cleaning standards against the final OPEX costs.

Chemical Energy

Introducing chemical energy into your wash process can be as simple as using water to wet the surface area of the plastic granulate. Typically, however, we are speaking about the emulsification of lipids or the neutralization of acids or alkalis.
Our friction washers have been designed to allow for chemical dosing via a dedicated storage tank. Once the wash liquor is spent it is fed through coarse and fine filtration ready for either safe disposal or recirculation depending on your situation

Mechanical Energy

The mechanical energy in the wash process is typically in the form of kinetic friction also known as dynamic friction or sliding friction. This is the force that occurs when two objects are moving relative to one another.

In terms of OPEX costs, this is the cheapest energy to create when compared against chemical usage or temperature. As you can tell by their name our Friction Washer’s predominant form of energy through the wash process is kinetic friction. This is created by both the impact of the spinning rotor but also by the impact of the plastic against itself.

Thermal Energy

The introduction of heat is an extremely effective way of removing contamination from a product, despite the intrinsic cost of its creation. As the temperature of the wash liquor increases the activation energy required reduces and decreases wash times, such the other factors remain constant.

Each of our friction washers can either be supplied with heated or ambient wash liquor to account for our customers varying needs. This can either be supplied directly from a source on your site or can be generated through steam, oil, gas or electricity by Rotajet products.

Contact Rotajet

We aim to get back to any enquiry within 12 hours, so please contact us if you are interested in a specific machine or would like to discuss an individual cleaning application. Our friendly team are happy to help via email at or by phone on +44 (0) 1924 271446.

Size Reduction​

Size reduction is a crucial step when processing plastic ready for reuse. Plastics are reduced in size, usually between 6 – 10mm, and then cleaned, dried and separated into reusable plastic granules.



Why is Size Reduction so Important?

Reducing the size of the plastic material is a vital part of recycling plastics for three main reasons:

1. Reducing the particle size of the processed material increased the surface area present. This results in a reduced energy requirement during washing and drying, thereby reducing operational costs.

2. Sink Float tanks are typically used to separate plastics according to their density. Uniform particle sizes ensure the reliability and efficiency of this separation process

3. In standard situations plastic resin is sold according to its weight and purity. Reducing the particle size of the final product increases the density of resin contained within any given space. In turn, this process lowers the associated costs involved in transportation and storage.

Contact Rotajet

We aim to get back to any enquiry within 12 hours, so please contact us if you are interested in a specific machine or would like to discuss an individual cleaning application. Our friendly team are happy to help via email at or by phone on +44 (0) 1924 271446.

Plastic Washing

Rotajet produces a range of machinery for washing plastics at various stages in the recycling line. This video shows the washing of mixed rigid plastics within a Rotajet recycling line. 

Rotajet Systems Ltd
Unit 14
Flanshaw Way
West Yorkshire

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