Poppet and Seat Design Criteria for Contaminant-Particle Resistance
Abstract
This final report describes analytical and experimental investigations to establish design criteria for reliable metal-to-metal poppet and seat sealing in contaminated fluid environments. Static evaluation of standard flat 440C models (0.470-inch seat diameter, 0.03-inch land) with placed hard (Rc 62-67) and soft (Rc 17-21) spherical metal particles defined envelopment closure loads and stress-leakage change characteristics. The control condition was nominally 0.01-scim nitrogen leakage at 1000 psig and 40-pound seat load. Envelopment loads, defined by leakage increase less than 10 times control, were determined to be nearly proportional to the particle diameter squared. The 30-micron diameter constituted an approximate upper size limit for the 0.03-inch land, with about 46 pounds required to envelope one to three equally spaced particles. Larger particles created a radial channel leak path necessitating substantial load increase to effect closure. Dynamic tests of four closure configurations in a recirculation liquid system containing a precisely controlled concentration of hard spherical metal particles provided correlation of impact frequency predictions based on a binomial analysis of concentration, cycles, and theoretical seat sampling volume. A hard poppet on soft seat combination was capable of sealing with larger particles entrapped. The particle avoidance concept was investigated experimentally and is a potentially fruitful approach to particle resistance.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1970
- Accession Number
- AD0878212
Entities
People
- G. F. Tellier
- J. W. Lewellen