2. Replacement of any portion of the vessel would require costly repair 

 procedures. The installed laboratory lifting facilities would not be sufficient 

 to assist in any disassembly. 



3. Welds, although made on relatively thin individual layers, except for the 

 end-closure flanges, would nevertheless be an added source of uncertainty 

 with regard to behavior under impact loading, cyclic stressing, etc. 



4. The fabrication is restricted to basically one company due to the proprietary 

 nature of this concept. 



Conclusions. The multilayer method has been sucessfully used in 

 some previous applications with operational pressures of 10,000 psi and could 

 be extended, with reasonable surety, to the 10-foot size required for the present 

 application. 



Recommendations. A 



complete design and cost estimate 

 should be obtained from the fabri- 

 cators. 



ndividual vessels 



i / // ///A^/)^ i 



I ^ 



)/////////. 



W 



Pi>Pk>Po 

 Pi " 2 p. 



R. R R: R 



I o I o 



unpressurized pressurized 

 Distribution of Hoop Stress 



Figure A-3. Separated layer concept of 

 pressure vessel construction. 



Separated Layer Concept 



The separated layer concept 

 consists of fabricating a vessel from 

 a series of individual shells (Figure A-3) 

 separated by annular fluid spaces. Two 

 systems have been briefly considered, 

 one allowing for continuous control 

 of the annular space pressures and 

 the other providing the initial pres- 

 surization to some prescribed values 

 with the subsequent magnitude of the 

 annular space pressures being deter- 

 mined by the deformation of the 

 vessels and the compressibility of the 

 fluid. 



A separated layer vessel theory 

 has been developed which assumes 

 that the maximum shear stress, T „, 



max 



at the interior of each layer, has the 

 same value. 



45 



