Accession Number : ADA953863

Title :   Investigation to Determine the Cause of Failure of the High Pressure Stem and Packings of the 150,000 lbs/sq. Inch Hydraulic Intensifier,


Personal Author(s) : Mann,H. C. ; Yatsevitch,M. G.

Report Date : 25 SEP 1934

Pagination or Media Count : 15

Abstract : The primary cause of failure was the threaded joint between the stem and stem head, and the design of the lower packing ring. This ring had no inner supporting lip and the pressure forced the lead filling out and into the thread section. This allowed the upper ring to come in contact with the lower ring which, due to its concave form acted as a die to turn in and collapse the outer lip, thus reducing the upper pressure contact area which resulted in greatly intensifying the pressure. This pressure intensification was sufficient to produce a tension stress in the stem in excess of the yield strength of the material which caused the stem to neck down. The lead and part of the lower packing ring forced into the thread section by the increased pressure acted as a wedge to produce a crack at the thread root which spread across the entire section causing rupture. Sudden release of the potential energy produced in the stem by the intensified pressure was sufficient to force the stem upward with considerable velocity.

Descriptors :   *Hydraulic pressure, *Stemming, *Hydraulic equipment, Rupture, Screw threads, Yield strength, Packaging, Rings, Potential energy, Fibers

Subject Categories : Mfg & Industrial Eng & Control of Product Sys
      Machinery and Tools

Distribution Statement : APPROVED FOR PUBLIC RELEASE