Cooled mechanical seal

Claim 1

A cooled mechanical seal assembly for a shaft passing from the free atmosphere through an opening in a housing wall, comprising, means defining a primary seal slide ring with a front working surface rotating together with the saft, means defining a primary seal counter ring and a sealing housing with said counter ring being mounted in said sealing housing, the sealing housing containing a medium to be sealed and wherein the counter ring is exposed to the medium to be sealed and is fastened so as to be axially non-displaceable and prevented from rotation in the sealing housing and essentially has a front face and peripheral and rear outer faces, means for spring-forcing a front working surface of the slide ring against said counter ring front face, and further comprising, means defining a mounting block portion of said sealing housing supporting said counter ring and comprising extension of its outer peripheral surfaces open to ambient air and enlarging it in available surface area accessible to the ambient air by cooling ribs therealong, said mounting block having at least a primary inner surface in direct butting metal to metal contact against peripheral and rear outer faces of the primary seal counter ring, the primary seal counter ring having an annular shoulder defined by a front step thereof, the mounting block including a clamping flange portion with a collar end projecting regularly inwardly in annular form and resting via an O-ring gasket against said annular shoulder to seal off the annular shoulder, and wherein at least the counter ring is made of a material with high mechanical strength, whose heat transfer coefficient is greater than 50 Kcal/m h C.° means defining a secondary seal with a slide ring and counter ring on the atmosphere side of the above said primary seal and wherein said mounting block has an inner portion with back to back seats separated by an inwardly extending portion of the mounting block so that the counter rings of the primary and secondary seals are mounted immovably and face in opposite directions, the secondary seal having said slide ring secured to the shaft for rotation therewith.