Loss-in-Weight Feeders assemble a feeding device, a weighing system, and a control system together to produce a gravimetric feeder. This feeder accurately doses or weigh bulk powders and ingredients into specific flow rates or batches. Material flowing from the weighing device is weighed and adjusted continuously so that the weight loss per unit time matches the required values. Filcoflex polyurethane weighing bellows serve an important function in loss-in-weight feeders. Once incorporated into the system, it prevents vibration or movement from influencing the accuracy of the weighing equipment. This ability reduces stress in the system and increases the machine’s service life.

Polyurethane materials are tested in compliance with ATEX regulations. ATEX, or Atmosphères Explosives, is a European Union directive that places requirements for equipment intended for use in environments with explosive hazards. This promotes both workplace and employee safety. Explosion resistance is the ability of PU flexible sleeves to withstand increase in pressure in case of explosion. PU sleeves scored between 1 to 1.5 bar, with some outliers scoring as high as 2 bars. On the other hand, electrostatic properties testing measured the ability of the PU sleeves to charge and cause powder explosion. Results showed that PU material cannot charge enough to produce an explosion in powders with minimum ignition energy (MIE) higher than 1 mJ.