When the UK-based pre-fried and frozen potato producer Agristo was looking to expand its production, they turned to Ajax Equipment—a company that had supplied the first three mixers at the potato plant.

According to Eddie McGee, managing director at Ajax Equipment, “Ajax has worked with Agristo over a number of years to refine its mixers to suit local site needs and enhance the production of Agristo’s potato products.” 

In 2015, the potato maker used one of Ajax’s hire machines to test various product combinations and handling requirements. The resulting feedback allowed Ajax to scale up the mixer’s design, producing a stainless steel continuous twin paddle mixer with a specially profiled casing for the most effective operation. The fourth mixer supplied continues this development, using Agristo’s experience with their existing machines and Ajax’s expertise to enhance mixing performance, according to McGee.

The stainless steel, twin-screw mixer uses a combination of paddle and Lynflow ribbon screw geometry to provide gentle mixing to grated potato and various additives, including flavorings, to produce a range of potato products with negligible damage to the ingredients. 

Twin-screw mixers are made up of two rotating, intermeshing screws operating within a profiled casing. The screw arrangement consists of a series of paddles arranged to form a discontinuous helix, a pair of ribbons forming a helix or a combination of the two. All of these options combine the ingredients, working them together in a zone between the two shafts while at the same time driving the material axially along the machine as the shafts rotate. The variables of the screw design, paddle size and shape, angle of the blades, as well as operating parameters—including material loading and speed of rotation—offer a high degree of flexibility and control over the mixing process. This enables each mixer to be tailored to the ingredients involved and degree of mixing required.

The continuous mixer has a range of hygienic features. The mixer’s casing and covers have a smooth figure-eight profile to ensure there are no “dead” areas for product to accumulate, and counterbalanced covers offer easy access. The mixer also holds water making it easy to agitate the screws within the casing, which effectively becomes a bath for a cleaning cycle. Once cleaning is complete, the mixer’s gentle incline ensures it fully drains.

“Since commissioning Agristo’s first Ajax continuous mixers almost five years ago, they have performed very well. As a result, when Agristo looked to expand its production… Ajax was the obvious choice,” says Dieter Raes, technical director, Agristo.