Vibrating screens are used widely in industry to separate granular materials or powders into different sizes. While there are many varieties of screens, they can be broadly classified into two groups: circular vibrating screens and linear screens. Knowing which type is best will depend on the nature of your application. This article discusses how to make the best choice, and please don’t hesitate to contact us directly, if you would like to discuss your business’ requirements in person with one of our team.
1) Mode of Operation
The primary distinction between the two screening processes is given by the trajectory of the product particles being processed. Simply put, circular screens move the particles clockwise around the surface of the screen generated by controlled horizontal and vertical motion.
Typically, the circular vibrating screen separator always operates in a horizontal position. The motor weight settings are configured to produce vibration of sufficient amplitude for a continuous vertical and circular motion on the surface of the screen, where smaller particles travel through each screen’s correct apertures, separated from larger particles which remain above a screen. These machines can provide very accurate classification if required with single or multi-level decks with dedicated output spouts for specific fraction delivery positions.
A linear screen uses a simpler vibration method, comprising of a vertical and forward motion. The unit is normally horizontally mounted on its support frame but can be in a declined position, and the particles move from the feed end down to the outlets at the other. Multi-layer screens may be used to produce several fractions. Linear screening can be used to screen but also transfer material from one location to another in one unit – again with delivery positions using dedicated spout designs.
With circular screens, the product moves within a relatively small area as it is filtered by the rotating motion allowing for a more compact machine with a smaller footprint. Linear screens, by contrast, need an extended operating area with start and end points. This must be long enough to allow the material to filter through whatever number of layers are required as it moves from input to outlet. Linear screens may be connected to a production pipeline, taking input, and offering output to other processes.
3) Hole Blocking, Pegging, Blinding
Hole blocking can be a problem for any vibrating screen system. As a general rule, with the correct aperture and type of screen, this can be minimised for both circular and linear screens. For some irregular shaped product material a linear screen with a slightly higher throughput (using larger screen sizes) may be more suitable as opposed to circular fine grading of powders or plastic pellets for example. For some certain powder product, particles that blind screen apertures, commonly known as pegging, Gough can provide an additional ultrasonic packages used to de-blind a screen very effectively.
4) Flow and Fraction
At Gough Engineering, we supply a range of options for both circular and linear screens. For circular sieves, we can provide either a direct single, centrally mounted motor (Vibrecon®) with up to 4 fractions exiting at different spouts, or two externally mounted motors for the Vibraflo® (flow through) design for just two fraction separation, with a central flow of material.
For linear screens, two motors are usually deployed, one on each side of the screen for continuous use over time. A further option which may be suitable for some operations as it uses electro-magnetic drives rather than regular motors for smaller scale separation where there may be a start/stop requirement.
Vibrating Screens From Gough Engineering
Linear and circular vibrating screens can all operate within a fully enclosed structure, which prevents dust spillage and reduces environmental contamination. Special lids with inlet spigots and optional viewing ports can be designed into the final solution. Additional extraction systems can also be designed with hoods and changeable filters if required.
Please call one of our technical sales team today for advice on choosing the right solution for your production requirements.