Patent Application
20100001475
This invention relates to mechanical seals in which the sealing element is a split cylindrical ring with an inner metallic expander providing a resilient force to energize ring for sealing the passage between two adjacent surfaces.
Split piston ring seals are typically made of polymeric Polyamide plastics such as Vespels, Peek, PTFE and Nylons where the split section of the seal is a “Z” shaped cut. This ring is expanded to be energized by a “C” shaped metallic spring which expands ring diameter larger than it's sealing bore surface and when it is pressed inside this bore diameter it provides sealing force at the point of contact between seal ring and its surface it comes in contact with.
Piston rings in variety of sizes are increasingly being used for a range of applications as dynamic sealing elements. They are exposed to high and low temperatures and pressures along with corrosive media and as the ring slides inside housing bore in reciprocating motion in order to compensate and makeup for this wear the “C” shaped spring which is inserted inside piston ring to compensate for wear as it reciprocates inside housing bore. Some cylinder bores have pressure holes drilled through their wall and whenever these holes coincide with the “Z” cut split section of ring create leak path and in order to prevent this leakage the seal ring has to be clocked so that this cut will always stay on the opposite side of holes in the cylinder wall, this invention makes it possible to prevent seal ring from rotating inside the housing bore.
A number of spring energizers are used to expand seal rings. As for example my prior U.S. Pat. No. 4,133,542 on configuration and method of making springs, my other prior U.S. Pat. Nos. 4,508,356 and 4,939,830, and 7,159,857 and SPRINGCLIP RING U.S. Pat. No. 6,419,236 which could also be utilized in conjunction with seal ring inside diameter. In order to minimize leak path through split “Z” cut section, this invention, also, makes it possible to close the seal ring gap at the split by simply offset spring ring ends so that it exerts longitudinal forces opposite each other at the split ends of seal ring to close end gap to minimize leakage.
The object of this invention is to provide an improved spring energizer that overcomes the deficiencies of the prior art. Thus, a steel wire of variety cross sections is coiled to specific diameters and cut to individual rings then open ends to a desired gap, when inserted inside the split seal ring groove it's ends separate, thus giving necessary contact force to provide sealing between two adjacent surfaces it comes in contact. Spring ring ends are separated longitudinally away from each other so that ends are not collinear and when installed inside seal ring groove it will provide opposite forces towards centerline to close gap at the “Z” cut portion of seal ring thus minimizing leak path.
Referring to the drawings, the piston seal ring assembly 10 consists of an outer seal ring 20 having an internal groove 32 and spring ring 21, the preferred form of seal ring 20 is a true circle with a split “Z” cut 22 where spring ring 21 is nested inside groove 32 beginning and ending at both ends of split cut 22, this creates an outwardly force along circumference of seal ring 20 resulting a larger diameter than it's original and when it is installed into gland cavity 41 and bore 40 creating a seal between two adjacent surfaces of bore 40. In the same manner, spring ring 21 is formed so that its ends 26 are pulled apart longitudinally and when installed inside cavity 32 it creates forces opposite to gap opening 30 bringing them closer together and minimizing leak path from one side to another. Spring ring 21 may also be bent inward, 24, towards center of its diameter and when it is inserted inside drilled hole 44 located inside groove cavity 41 this will prevent seal ring 10 from rotating inside gland cavity 41.
