ISO 9809-4:2014 pdf free

ISO 9809-4:2014 pdf free.Gas cylinders – Refillable seamless steel gas cylinders
The external diameter and thickness of the formed neck end of the cylinder shall be adequate for the torque applied in ftting the valve to the cylinder. The torque can vary according to the diameter of the thread, the form of the thread, and the sealant used in the fitting of the valve.
NOTE For guidance on torques, see ISO 13341.
In establishing the minimum thickness, consideration should be given to obtaining a thickness of the wall in the cylinder neck which will prevent the permanent expansion of the neck during the initial and subsequent fittings of the valve into the cylinder without the support of an attachment. The external diameter and thickness of the formed neck end of the cylinder shall not be damaged (no permanent expansion or crack) by the application of the maximum torque required to fit the valve to the cylinder (see ISO 13341) and the stresses when the cylinder is subjected to its test pressure. In specific cases [e.g. very thin-walled cylinders ) where these stresses cannot be supported by the neck itself, the neck can be designed to require reinforcement, such as a neck ring or shrunk-on collar, provided the reinforcement material and dimensions are clearly specified by the manufacturer and this configuration is part of the type approval procedure.
When a foot ring is provided, it shall be sufficiently strong and made of a material compatible with that of the cylinder. The shape should preferably be cylindrical and shall give the cylinder sufficient stability.The foot ring shall be secured to the cylinder by a method other than welding, brazing, or soldering. Any gaps which can form water traps shall be sealed by a method other than welding, brazing, or soldering.
When a neck ring is provided, it shall be sufficiently strong and made of a material compatible with that of the cylinder and shall be securely attached by a method other than welding, brazing, or soldering.
The axial load to remove the neck ring shall be greater than 10 times the weight of the empty cylinder but not less than 1 000 N, and that the torque to turn the neck ring is greater than 100 Nm.ISO 9809-4 pdf download.