Double-acting rupture disc POS-A-SET®

flat seatmetalultra-low-pressure

Relieve ultra-low vacuum or positive pressure conditions with the highly accurate, bidirectional POS-A-SET rupture disc. Our double-acting design allows the POS-A-SET to do the work of two rupture discs with just one installation point. It relieves low positive pressure (as low as 1 inwc) with a girdle and knife-blade assembly on one side, while slightly higher negative pressure is relieved from the other side with perforations and a pre-cut section. The POS-A-SET’s easy-to-clean flat seat design reduces product buildup, making it easier to meet FDA requirements. Looking for the CAL-VAC rupture disc? Nearly identical to the POS-A-SET rupture disc, the CAL-VAC relieves ultra low-pressure in the negative direction – the inverse of the POS-A-SET’s ultra-low relief in the positive direction. Contact us if you aren’t sure which you need. Two sides to the POS-A-SET rupture disc As system pressure approaches the burst pressure setting on the ultra-low positive pressure side, a girdle is loaded until it deflects back past a knife-blade assembly in the holder. As the girdle passes the knife blade, the seal is divided in a triangular pattern to relieve the pressure. CAL-VAC rupture discs vs. POS-A-SET rupture discs The difference between the CAL-VAC and the POS-A-SET is the orientation of pressure relief components. The CAL-VAC relieves ultra low-pressure in the vacuum (negative) pressure direction, while the POS-A-SET rupture disc relieves ultra-low pressure in the positive pressure direction.