Abstract: A cylinder valve outlet includes a bore with a large cylindrical entry leading to a tapered seat. A nipple with a cylindrical neck is fit into the large diameter entry of the bore of the valve outlet. The nipple further includes an arcuately convex mating end for seating in the conically tapered seat of the valve outlet. A seal enhancer is between the valve outlet and the nipple. The seal enhancer is generally tubular with opposed leading and trailing ends and a cylindrical section therebetween. The leading end is tapered for engagement between the tapered seat of the valve outlet and the mating end of the nipple. The trailing end of the seal enhancer is flared outwardly. The seal enhancer is shorter than the mating portions of the nipple so that the outwardly flared trailing end is visually readily apparent. The outwardly flared trailing end also facilitates separation of the seal enhancer from either the nipple or the valve outlet when the gas cylinder is being replaced.

Abstract: A high pressure fluid fitting is provided for repeated connection and disconnection. The fitting includes a threaded nipple and a flanged nipple configured for abutting end-to-end mating with one another. A thrust bearing formed from a metal harder than the flanged nipple is positioned adjacent the flange and on the side thereof opposite the mating face of the flanged nipple. A coupling nut with an inwardly extending annular flange is disposed over the flanged nipple and is threadedly engageable with the threaded nipple. The flange of the coupling nut moves against the thrust bearing and urges the nipples into tight sealing engagement. The smoothness and hardness and chemical dissimilarity of the thrust bearing avoid galling and other friction related damage to the fitting, and hence lead to an extended life for the fitting.