SMG - Screw Press

Using a very straightforward design, screw presses only have one moving part to generate the required pressure to compact and squeeze out the liquid element, making them a cost-effective, minimal maintenance machine.

Compact in size, consists of a cylindrical sieve screen that has a slow revolving screw through its centre that has a specifically designed screw flight/spiral that gets progressively tighter towards the discharge end, to create the force needed for the compaction. The input material is delivered to the inlet of the machine (the method is determined by its form) and is taken into the sieve screen by the revolving screw, starting the separation process.

• A fixed choke is generally a bolt-on reducer, extended pipe, or chute.
• Manual – set the position of the variable flap to the required aperture size.
• Automatic – constantly adjusts the aperture size of the discharge with either weighted, spring-loaded, or pneumatic controlled flap/cone to maintain the desired back pressure.

Depending on the application, and the forces & pressures exerted, we offer two options for the sieve screen:

• Wedge Wire screens are generally used for fine sieving, to leave as much solid matter in the dry element as possible and where the input material is relatively clean (no chunks of wood or plastic, etc.).
• Punch Plate screens are generally used for dirtier input material but cannot fine sieve to the same level as wedge wire. These screens can have built-in Break Bars that stop jamming from larger objects by breaking/slicing them into small pieces.

Using compaction to squeeze out the liquid provides many benefits over non-compaction units:

• A vast array of slurries, sludges, pastes, liquids, and products can be dewatered with a screw press that cannot with non-compaction, for example, thick and unpumpable, high in dry matter, viscous, sticky/gloopy, pastes/creams, foodstuffs/fruit/veg, and highly compressible and absorbent solids content products. Most products that have suspended solids can be dewatered with these machines except for certain entrained incompressible solids, for example, certain aggregates, etc. as these can compact and/or bind, causing the screw to stall.
• Higher levels of separation as finer sieve screens can be employed meaning greater quantities of solid matter in the dry element and less in liquid.
• Compacting the dry element means it is considerably drier (high dry matter), smaller in volume, and generally stackable, therefore doesn’t need a contained storage area.
• Certain applications require particles smaller than 100 microns to be removed. This can be overcome with coagulation and filtration technologies – visit Coagulation and Filtration on this site for more details.