Performance
Sealability
Die Molded Rings for Dynamic Applications
Die Molded Rings as Static Seals
TABLE ES-108
Performance
Grafoil die molded ribbon-pack (DMRP) rings, manufactured by EGC Enterprises,
guarantee performance. Each ring is molded from Grafoil ribbon pack
material with precision dies designed for critical sizing of Grafoil
rings. Grafoil has proven itself superior to other materials, making
a significant difference in production, downtime and most importantly,
safety.
Each ring is held to a closer tolerance than any other molded ring on
the market, ensuring proper performance in all temperatures, mediums and
pressures . . . while providing optimum sealability in valves and pumps.
EGC die molded rings are supplied in a multitude of shapes and styles, from the smallest tube
ferrule to large 24" body seals. Die Molded Rings for Dynamic Applications Several design criteria must be considered when using die formed rings as seals. The following we find to
be the most important.
1) Leak requirements: Can the application allow slight permeation of
gas. By the nature of their construction die molded parts can permeate
gas.
2) Proper sizing: per ES-108, die molded rings should have a slight interference
fit on the O.D. and a slight clearance on the I.D. of the ring.
3) Axial to radial loading: dynamic sealing requires special attention
to the friction. Flexible graphite displays one of the highest axial
to radial load transfers of any sealing material. Because of this,
special care in selecting ring density must be observed.
Die Molded Rings as Static Seals Die molded rings as
static seals must be contained on both I.D. and O.D. and typically become face seals. The same sealing principals apply however, and the installed density governs sealability.
1) Tolerances: much more critical than a standard ring. Height
must be controlled along with the initial density. This leads to rings
that are weight-sorted.
Ring O.D.: Nominal stuffing box I.D. + C
