US 4380154

I'll search for authoritative information on US 4380154, including any 2026 CAFC activity.

Let me run targeted searches for litigation/docket activity and an alternate identifier check.

US Patent 4,380,154 — "Clean Coal Power System"

Search scope note: I searched Google Patents (full authoritative text), OSTI/DOE, FreePatentsOnline, Justia, and open-web sources for CAFC/PTAB/2026 docket activity tied to this number. I found no 2026 (or any) CAFC docket, PTAB/IPR, or reexamination proceeding involving US 4,380,154. There is no litigation history I can verify for this patent. Treat the "no litigation found" statement as a negative search result, not proof of non-existence.

Bibliographic data

Source: https://patents.google.com/patent/US4380154/en ; https://www.osti.gov/biblio/6218322

Abstract (as issued)

A coal-burning power plant producing electricity at high efficiency with very low atmospheric contamination. A fluidized bed of limestone and coal burns the coal with little air pollution, and a large quantity of specially constructed heat pipes transfer heat to a closed-cycle gas turbine with very low temperature loss. Preferred heat pipes have steel casings, a thin aluminum oxide layer to prevent hydrogen permeation into the casing, and a plasma-sprayed ceramic coating on the portion within the fluidized bed to prevent erosion of the casing by solid particles in the bed.

Claim structure

The patent has 13 claims with exactly one independent claim — claim 1. Claims 2–5, 9, 10, 11, 12 and 13 depend from claim 1; claims 6–8 depend from claim 1 (with 7 and 8 depending from 6).

Independent claim 1 (plain language)

An apparatus for producing mechanical power, combining four elements:

1. A fluidized-bed combustor into which air, coal and limestone are introduced, where the coal burns to create heat and the limestone chemically combines with sulfur in the coal to form solid compounds;
2. Solids-removal means attached to the combustor to remove those sulfur-bearing solid compounds;
3. A closed-cycle gas turbine that uses hot gas supplied to its input to create mechanical energy; and
4. A heat exchanger whose first part connects to the fluidized-bed combustor and whose second part attaches to the gas turbine input, heating the turbine gas before it enters the turbine — the exchanger comprising multiple heat pipes with casings carrying (a) a continuous, impermeable oxide layer approximately one micron thick, and (b) a second ceramic coating between 0.010 and 0.125 inch thick covering at least the portion of the heat pipes immersed in the fluidized bed.

The protective dual coating on the heat pipes is the core structural limitation distinguishing claim 1.

Dependent claims (plain-language gist)

• 2 — The heat-pipe casings are steel.
• 3 — The impermeable oxide layer is selected from aluminum, silicon and titanium oxides.
• 4 — The second ceramic coating is selected from oxides of aluminum, silicon, titanium, magnesium and calcium.
• 5 — More than one thousand individual heat pipes are used (the redundancy/non-catastrophic-failure rationale).
• 6 — Combustor and heat exchanger are built as a single vessel with a gas-tight barrier wall separating the turbine input from the combustor, with the heat pipes penetrating that wall.
• 7 — The heat pipes are individually removable/replaceable, being bonded to gas-tight attachment means removably attached to the barrier wall (bolt-on flanges).
• 8 — The vessel is configured so the second (turbine-gas) part of the heat exchanger sits vertically above the fluidized-bed combustor.
• 9 — The second part of the exchanger comprises heat-exchange fins on the heat-output ends of the heat pipes inside a turbine-gas chamber.
• 10 — Alternative architecture: the second part of the exchanger is piping mounted internal to the heat pipes, through which the turbine gas flows (the FIG. 4 manifold embodiment).
• 11 — Adds a precipitator to remove solids from combustion gases.
• 12 — Adds means to extract usable heat from exhaust gases (e.g., boiler 26 for auxiliary vapor).
• 13 — Adds an electrical generator mechanically coupled to the gas turbine.

Points of uncertainty / caution

• Inventorship discrepancy: A scraped Justia assignee listing appears to pair this patent's abstract with "Filed: September 28, 1981 / Date of Patent: October 11, 1983 / Inventors: George Y. Eastman, Donald M. Ernst, Warren E. Thomas." That pairing is inconsistent with the authoritative record (filed 1981-06-23; issued 1983-04-19; sole inventor Eastman) and appears to be a scraper artifact interleaving entries for a different Thermacore patent. I rely on the full-text record: sole inventor George Y. Eastman.
• Term/expiry: Google Patents shows an "anticipated expiration" of 2001-06-23, but the legal-events record shows the patent lapsed 1991-04-21 for non-payment of maintenance fees. The enforceable term therefore ended in 1991, not 2001.
• No verified 2026 CAFC/PTAB activity could be located for this number; other hits for the string "4380154" belong to unrelated registrations (e.g., a Japanese patent JP4380154B2 for soil solidification, an FCC license ID, a trademark registration number), which should not be conflated with US 4,380,154.