PSI-Polymer Systems sells modified CSC continuous screen changer for a food industry extrusion application

PSI-Polymer Systems has recently sold a modified continuous screen changer to a U.S.-based candy producer for use in what the company called a "challenging food extrusion application."

This purchase marks the fifth PSI screen changer this customer has purchased for their food process. The first one went into service in 2011.   

"This particular food application was new for continuous screen changers back then. There were trials that had to be run and validation procedures met, but more than that, months of in-service operation had to be performed to make certain that the metallurgy would stand up over several years and rigorous FDA conditions upheld without fail," said Don Macnamara, general manager of PSI-Polymer Systems Inc. "Whether it's plastics, food, or other materials, it's our job to adapt technology to the process."

There are several unique challenges of running a food application with a machine generally used for plastic extrusion, which include the ability to thoroughly clean any area where bacteria might grow; accommodate water wash down and be watertight to facilitate this washing; be built entirely of stainless steel to resist rusting; use FDA approved paint, and have exterior surfaces free of nooks and crannies that can catch and hold food and cause bacterial growth.

PSI' s customer was clear that the process could not tolerate any machine downtime for filter changes, meaning the screen changer had to be continuous to allow for an automatic switch from a clogged or potentially contaminated screen to a new, clean screen without shutting the line down. 

The PSI screen changer is a continuous design with easy to change screen packs. It is made of 420 stainless steel to allow for heat-treating while also resisting corrosion and rusting. Additionally, as was required, the screen changer is watertight and has the ability to process the extremely high viscosity of this food application. 

Hydraulic slide plate screen changers have traditionally been used in the food industry, for batch applications such as cereal, corn chips and others. However, the PSI continuous screen changer accommodates 24/7 continuous extrusion operations and allows for an automatic, easy switch of screens which eliminates downtime and creates a system that is both more efficient and less susceptible to contamination than the standard hydraulic version.

 "This is an exciting application for us here at PSI," said Glenn Woodcock, president of PSI-Polymer Systems. "The challenge of developing a screen changer that meets all the standards of the food industry while still increasing efficiency and value for the customer is something we believe not many companies in this business could have overcome. We at PSI pride ourselves on our ability to innovate and push the boundaries, and we have done so yet again."