Abstract: A sealing system for use in a chemical or gaseous delivery system has a delivery tube connected to a source of the material to be delivered and which intrudes into the revolving region where the material is to go. The sealing system has a secondary sealing nut affixed to the delivery end of the tube, and a primary sealing nut mounted on the secondary nut with a sealing member therebetween. When the region revolves, the two nuts are automatically tightened to hold the sealing member in firm and positive engagement with the housing surrounding the region.