TurboCare v. General Electric Co. (JWB)

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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


  • 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


  • 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.”

Class Notes

  • GE has four inventions that Turbocare says they infringed on (infringed on claims 1, 2, 5, 6, 7)
  • District Court ruled that claim 2 was invalid, and 1, 5-7 were not infringed
    • Claim 2 involved new material
    • originally springs/compressed springs – Brandon added ‘flat springs’


  • high pressure side and low pressure side of turbine
  • seals shaft such that all the high pressure fluid is forced through turbine to get work out of it
  • springs force it out to give it a larger diameter – if nothing forces springs, clearance gets larger
  • want larger clearance as it speeds up
  • as pressure builds outside, springs are compressed and you get a tighter seal

Revision of Claims

  • Brandon's original disclosure stated that a “considerable variety of springs 16 can be employed…Flat, S-shaped springs are illustrated, but others can be employed.”
  • Revised to be “S-shaped springs are illustrated, but flat springs and others can be employed”
  • CAFC ruled that summary judgment was not allowed because issue of fact existed
    • Jury could rule either way
  • Claim 2 was ruled invalid
    • All limitations of claim must be disclosed
    • Examiner rejected Brandon’s claim that ‘between’ or ‘adjacent to’, stating they were not the same thing
    • Brandon revised to include just ‘adjacent to’

Means Plus Function

  • §112

“An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure…such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof”

  • It is to be interpreted in regard to what is disclosed in the specification” ~Patent Manual



  • District Court: Summary Judgment – did not infringe claim 1, 5, 6, 7; claim 2 invalid
  • Claim 2 invalidity affirmed due to new matter (disclosure)
  • Claims 1, 5, 6, 7 – partial affirm, partial remand (2 out of 4 GE inventions are non-infringing)

The Patent

  • Steam pressure limits closure and seals the escape to annular section
  • GE Products similar – bias springs outward until pressure got higher

Claim 2

  • Claim 2 was amended during prosecution, adding leaf springs
  • “We conclude that there is an issue of fact as to whether Brandon's amendment, which explicitly discloses flat springs, added new matter to the specification. Consequently, 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.”

  • Original disclosure was close enough, that perhaps flat springs may be supported
  • Not only TYPE of spring, but also LOCATION of spring
  • Only one location specifically disclosed – at the “end of each seal-ring segment”
    • Original claim had “end or adjacent” to seal-ring segment
    • Examiner rejected original claim because it was indefinite
    • Amended claim: “radial position means biased against segment”
      • New dependent claim: specified flat springs and specifies location at shoulders
  • “The missing descriptive matter must necessarily be present in the original application’s specification such that one skilled in the art would recognize such a disclosure”
    • 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.
    • “all the limitations must appear in the specification”

Claims 1, 5, 6, 7

Radial Positioning Means

  • can write a claim with “means plus function”, which goes back to specification
  • Claim 1 states that the function of the “radial positioning means” is to position the ring segments such that spring forces dominate at low speeds/low turbine loads, and the pressure forces to dominate at high speed/high turbine loads
  • Warth (British patent) anticipated leaf springs
    • Brandon’s is two-position seal (either open or closed) – distinguish from Warth, which employs leaf springs with nearly frictionless ring segments that gradually allow the ring clearance (gradual, not open/closed at all times)
  • GE claimed that they surrendered subject matter, but CAFC disagreed

Large Clearance Position

  • District Court said ‘large clearance position’ required that the outward facing surface of the inner ring portion of the seal ring segment touch the inward facing surface of the casing shoulders when the seal is in the large clearance position
  • CAFC – there is no basis for reading a limitation in such a way

Small Clearance Position

  • arguing over contact in different places and different type of contact
  • says “direct contact” in some places and “contact” in others, implying that when “contact” is used, “direct contact” is not required
  • District Court and CAFC disagreed