Metallized Carbon Corp.

Mechanical seal rings are used to seal the clearance between the rotating shaft and the stationary housing in equipment such as pumps and mixers, so that liquid can not leak out through this clearance. These sealing mechanisms are often referred to as shaft seals or pump seals. Metallized Carbon Corporation manufactures the mechanical Primary Rings or CarbonGraphite Wear Faces used in many of todays most sophisticated and reliable mechanical seals for industrial, aerospace and military applications. These mechanical seal assemblies usually consist of a primary seal ring manufactured using carbon graphite materials, a counter face ring, secondary (O-ring) seal rings, springs, fasteners, and a metal housing. Mechanical seal assemblies are also used to seal gases in high speed compressors. These dry gas seals are double mechanical seals that utilize a controlled barrier gas and spiral grooves in the counter face which provide aerodynamic lift off or gas lubrication between the seal faces. Mechanical seal primary rings can be supplied to customer drawings and specifications. The rings can be supplied plain, shrink fitted or cemented in metal retaining rings. Metcar mechanical seal rings can also be supplied with the sealing face lapped flat to one helium light band.

Radial seal ring assemblies are used to seal the clearance between a rotating or reciprocating shaft and the stationary housing on many types of machines. Carbon-graphite radial seal assemblies were developed to help solve serious leakage problems that occur when materials such as leather, plastic, composite or elastomeric materials are utilized in the stuffing box seals installed on industrial blowers, pumps and other turbo machinery. These problems occur because of wear, thermal degradation, chemical attack and dimensional stability problems with elastic seal ring materials. To accommodate some anticipated movement in a reciprocating or rotating shaft such as thermal expansion or run out, carbon-graphite radial seal rings are normally designed to float with OD clearance within a chamber in the stuffing box. This allows a close clearance seal to be maintained between the OD of the shaft and the ID of the carbon-graphite seal ring. Leakage around the OD of the carbon-graphite seal ring is minimized by using a close clearance between the width of the carbon-graphite seal ring and the width of the metallic seal housing cavity. There are two types of carbon-graphite radial seal rings. Close clearance carbon-graphite seal rings are one piece, solid rings that are made to fit with close clearance on the OD of the rotating or reciprocating shaft. If the shaft is expected to expand because of thermal expansion, the carbon-graphite ring should be shrink-fitted into a metal retaining ring. This affords the carbon graphitemetal assembly the same thermal expansion rate as the shaft. The metal retaining ring shrink fitted around the carbon graphite clearance seal should be of the same metal as the shaft. This allows the close clearance between the shaft OD and carbon-graphite seal ring to be maintained even at high temperatures.