Invalidity dossier
US 5908493
Filtering system for cleaning air
Current assignee: Individual
Added 9/23/2026, 6:22:23 PM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 5,908,493 A
Title: Filtering system for cleaning air
Source: https://patents.google.com/patent/US5908493/en (fetched 2026-09-23)
Bibliographic data (as listed):
- Patent number: US 5,908,493 A
- Application number: US 08/971,738
- Inventor: Mark D. Krymsky
- Original assignee: Individual; current assignee listed as Individual
- Priority/filing date: 1997-11-17
- Publication (grant) date: 1999-06-01
- Anticipated expiration: 2017-11-17
- Legal status: Expired – Fee Related
- Classifications include A47L 9/18 (liquid filters, suction cleaners), B01D 47/02, and B01D 50/40
Purpose and plain-language scope:
The patent describes a multi-stage water filter for cleaning air, intended to replace bag filters and cyclones in household vacuum cleaners or to be used alone. Contaminated air is forced into the device rather than suctioned, and is impinged against a water surface to mix air with water; the air is then separated from the water several times to improve cleaning.
The first embodiment has a cylindrical main body containing a coaxial hollow cylinder, forming a ring-shaped (annular) chamber with a semi-spherically shaped bottom partially filled with water. Contaminated air enters the annular chamber through an entrance nozzle located above the water level (the excerpt is cut off at this point).
The specification states the device performs two main functions: thoroughly mixing contaminated air with water, and separating and collecting water from the mixture. Advantages asserted over the Rainbow-type liquid cleaner include use of forced air (greater impulse and kinetic energy), low aerodynamic resistance, separation in a ring-shaped rather than cylindrical chamber, a concentric three-step water-from-air separation replacing a rotating slotted separator (reducing clogging), operation at an inclined position, and possible mounting on an upright cleaner handle. Ten figures (FIGS. 1–10) are described, including two embodiments and a schematic upright-vacuum-cleaner incorporation.
What the excerpt does not establish:
The excerpt omits the claims, the detailed description of the second embodiment, and any specific prior-art references beyond named patents (e.g., Rainbow-related U.S. Pat. Nos. 2,221,572; 2,228,750; 2,886,127; 2,945,553; 4,640,697; 4,824,333). It provides no claim language, no examination history, and no verified legal conclusions regarding validity, enforceability, or ownership.
Generated 10/1/2026, 9:42:47 PM
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Litigation summary
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Proceedings on file (0)
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No PTAB proceedings on file. This patent has not been challenged via IPR, PGR, or CBM. The absence is itself a signal — well-asserted patents eventually attract IPRs. The LLM analysis below may surface filings the ODP feed hasn’t indexed yet.
PTAB challenges
AIA trial proceedings at the USPTO Patent Trial and Appeal Board — IPR, PGR, and CBM. Petitioners, judge panels, claim-level invalidation outcomes from Final Written Decisions, and Federal Circuit appeals. The single most important defensive datapoint after litigation history.
Assignment history
Inventors, original assignee, and the chain of ownership recorded with the USPTO — including the correspondent attorney who recorded each assignment, since shell-LLC chains often share one repeat-player attorney even when the entity names look unrelated. Surfaces NPE / patent-troll patterns: shell-entity transfers, known asserters in the chain, repeat correspondent fingerprints, pre-litigation assignments, and bankruptcy fire-sales.
Prior art
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Obviousness
Combinations of prior art that suggest the claimed invention would have been obvious under 35 U.S.C. § 103.
Extensions
Patent term adjustments, term extensions, continuations, divisionals, family members, and expiration dates.
Derivative works
Defensive disclosure: derivative variations of each claim designed to render future incremental improvements obvious or non-novel.