Linden Industries was the first equipment manufacturer to utilize hydraulically controlled orifices on a mixing head. The technology was developed for an automotive seating line manufacturing dual density cushions. The center of the cushion required a softer foam, while the perimeter needed to be firmer. With hydraulically controlled orifices the ratios could be changed on-the-fly so that the entire cushion could be produced by a single mixhead utilizing a robot to achieve the desired pour pattern.

This new technology provided a 4 to 1 ratio change in 0.5 seconds. In this application, the mixhead, with automatically controlled orifice pressure, is a 6-stream L-Head unit currently dedicated to 4 stream processing.  Three of the four streams could be selectively turned on or off as required. This technology is also available in a 2, 4, 5 and 6-stream impingement mix head.