3. If desirable, an extra ring could be fabricated for use in metallurgical tests 

 and test of fabrication suitability. 



4. No welding would be required on the shell body. Thus, fabrication costs 

 are reduced and reliability is enhanced. 



5. Failure of the liner would result in loss of water from the tank, but would 

 not cause failure of the rings. Even if one ring were to fail, the cost of repair 

 would be much less than the cost of replacement of the entire tank. The 

 facilities available for handling the closure would be adequate to disassemble 

 the vessel ring by ring and replace the damaged ring. 



6. Analysis of the ring behavior is fairly straightforward since the end closures 

 are not attached to the shell body and each ring behaves in approximately the 

 same manner. 



Undesirable Features 



1. The total weight of steel used in the construction will be at least 50% greater 

 than in a multilayer construction because a separate system of structural mem- 

 bers must be employed to restrain the end closure. 



2. Design of the end closures and of the discontinuous tie-rod restraint systems 

 will be difficult as little is known about them. 



Conclusions. From the standpoint of feasibility of fabrication, cost of 

 fabrication, reliability (including inherent safety, ease of inspection, etc.), ease 

 of operation, and maintenance, the stacked-ring concept rates very high. An 

 independent device (yoke or tie rods) is required for taking the axial load, but 

 such a device appears to be desirable regardless of the type of tank employed. 



Recomnnendations. It is recommended that an exploratory design be 

 made according to this concept in order to obtain firm cost estimates for 

 fabrication of a stacked-ring pressure vessel. 



Multilayer* Concept 



Discussion. A multilayer pressure vessel is made up of a number of 

 concentric cylindrical shells. Construction of a multilayer vessel begins with 

 rolling and welding of the vessel's inner cylindrical shells, which may be made 



A. 0. Smith trademark. 



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