What feeder for sticky products?

Sticky products are always going to present problems for accurate feedrate control but before we talk about the pros and cons that will help you choose a feeder for sticky products, we need to talk about what being sticky means.

What is a sticky product?

Words like sticky don’t really help narrow down the handling properties of a material very well. Sticky means different things to different people. So far example, do we mean the product clumps together? Or do we mean it will stick to the walls of a hopper or coat a screw flight?

And what causes the stickiness? Is it a moist food product such as a raisin that naturally tends to be sticky? Or is it a powder that compacts and forms a large lump if compressed too much?

Clearly some of these issues may require extra product treatments to make the material flow correctly. This might include coating them, freezing them, passing them through sieves or lump breakers and so on. 

If a material tends to coat a metal surface, then a machine such as the Brabender Flexwall may overcome this issue in the area where most flow issues can occur in a feeder – the feed trough. If a material coats and fills a solid flight screw, then a twin screw device may work better than a single screw feeder as the rotating flights on a twin screw tend to clean each other.

Pre-treating a product may also be the best solution, such as coating food products so they break up and don’t form lumps, allowing the ingredients to be accurately mixed together rather than having a large amount in one packet and none in the next!

But what feeder should I use?

Testing different options is the best way to get an answer to this question. And tests need to be done as close to factory conditions as possible as issues such as temperature and humidity may well change the material’s handling characteristics.

A few days in the lab or with a rented machine on site will save dealing with unforeseen and expansive issues later on.

As always the team at Genesis are here to help. We have seen hundreds of different product types and would be happy to discuss any of yours that you are concerned about. We’re also available to set up product trials so we can help you select the best configuration for your process line.