TurboCare v. General Electric Co. (JWB)

The Case

• Turbocare (Plaintiff-Appellant) and GE (Defendant-Appellee) in Court of Appeals
• Turbocare owner of ‘311 patent for a shaft sealing system for fluid turbines
• Suit brought against GE in district court of Massachusetts asserting infringement
• DC granted summary judgment of noninfringement for claims 1, 5, 6, 7 and invalidity on claim 2

The Patent

• improved labyrinth-type shaft seal for use in fluid-driven devices such as steam turbines
• steam turbines typically divided into stages separated by internal walls known as diaphragms (which include nozzles for steam passage and central openings for the rotating shaft)
• steam can leak through central opening causing inefficiency
• labyrinth-type seals are used to reduce leakage

Infringement

• springs apply a radial rather than circumferential force.
• As the steam load on a GE turbine rises, the pressure on the seal ring increases until the bias of the springs is overcome and the seal ring segments move radially inward to the small clearance position
• The 1992 N-2 Version includes similar side seal structures as well as dowels that allow the seal to be adjusted to accommodate non-standard and out-of-round conditions of the casing. The small clearance position is therefore defined by contact between the side seals and the dowels.
• DC held claim 2 invalid for lack of written description – Brandon amended his specification
  • DC found that the amendment was new matter and invalid
  • because the amendment was not considered, the district court concluded that claim 1 and the dependent claims did not cover a shaft seal with flat springs interposed between the casing shoulder and the inner surface of the outer ring portion of the ring segment

Ruling

• Turbocare challenges DC conclusion that new matter was added to the ‘311 patent (invalidating claim 2)
• When amending, new claims must find support in original specs
  • Brandon stated that “S-shaped springs are illustrated but others can be employed” and amended to “flat springs and others can be employed”
  • we cannot uphold the district court's summary judgment of invalidity as to claim 2 based on the asserted inadequacy of the original disclosure as to the type of spring used in the seal
• Brandon only specified springs “located at each end of each seal ring segment in a compressed condition” but then claimed “located between seal ring segments or adjacent to said rings”, which is not the same thing.
  • Turbocare argued one ordinarily skilled in the art would recognize that the only viable location for springs ‘adjacent to said rings’ would be between casing shoulders and the shoulders of the outer ring portion, and therefore the claimed matter was inherent to original disclosure
  • Ruled: Brandon's original disclosure is completely lacking in any description of an embodiment in which the spring is located between the casing shoulders and the inner surface of the outer ring portion of the ring segment. – not enough for written description requirement
• The “working fluid” limitation should be construed to exclude devices in which steam is admitted to the space between the casing and ring segments through a drilled hole above the ring. But that limitation should not be interpreted to exclude any device in which steam is admitted through a drilled hole, regardless of where the drilled hole is located.
• While the “large clearance position” certainly encompasses the preferred embodiment, it also encompasses an arrangement in which there is contact between the outward facing surface of the outer ring portion of the seal ring segment (i.e., the top of the seal) and the inward facing surface of the casing groove.
• For ‘small clearance position’ and the word ‘contact’, the district court properly construed the term, according to its ordinary meaning, to mean “touching.”
• the Original Version and the 1992 N-2 Version These devices do not infringe claim 1 as construed. They both have a drilled hole above the ring to admit steam into the space at the top of the seal segment
• 1992 Diaphragm Version
  • meets large clearance position limitation, but GE contests that it does not meet the small clearance position limitation
  • not literally infringing because the outward facing surface of casing shoulders and outer ring portion of seal segment are not touching
• 1995 Version
  • does not literally infringe for same reasons as 1992

• “the issue with respect to the doctrine of equivalents is whether the intrusion of the dowels between the casing and the ring segments creates any substantial differences between the claimed invention and the accused devices”

• “We remand the case to the district court to consider whether the 1992 Diaphragm Version or the 1995 Version infringes the ′311 patent under the doctrine of equivalents and to consider the validity of claims 1, 5, 6, and 7 in light of our claim construction.”