The assignee ranking for this dataset covers five companies, with the leading assignee holding 9 records and the fifth-ranked holder just 1. This is a small ranking, not a top-50 or top-100 list, so it should be read as the complete set the data endpoint returns rather than a sample. Several of the individual inventors named in the ranking also appear together as co-assignees on shared filings, suggesting a tightly connected filing group rather than a broad competitive field.

US4909266A, titled 'Ultrasonic cleaning system' and granted in 1990, is the most-cited document in this dataset at 62 citations — far ahead of any other record. It covers a multi-transducer tank design with a selective switching system that sequentially activates transducers to raise cavitation intensity. Anyone drafting claims around transducer placement or switching logic should review it closely, since later documents in this space cite it heavily.

In this dataset, G21F (radiation protection and shielding) appears in 75.0% of the 12 records in scope, nearly as often as the general cleaning class B08B at 83.3%. This reflects a distinct use case: ultrasonic cleaning systems adapted for decontaminating radioactive or nuclear-adjacent components, evidenced by titles like 'Radiation hardened ultrasonic cleaning system'. It is a separate technical branch from conventional parts washing, not a coincidental overlap.

The filing trend in this dataset peaked at 9 records in 2017 and has not reached that level again, falling to 0 in the most recent year. However, publication typically lags actual filing by around 18 months, so the most recent year understates real activity and should not be read as a definite slowdown. With fewer than four complete years once that lag is accounted for, no reliable growth rate can be stated from this evidence.

The IPC composition shows dense coverage in general cleaning (B08B) and radiation protection (G21F), but comparatively thin representation in areas like semiconductor-wafer fixturing (H01L) and nuclear reactor component servicing (G21C), each at 16.7% of the 12 records. Frequency-selection algorithms for cavitation tuning and bath degassing control are named in the search scope but do not dominate any single IPC class, suggesting room for more specific claims. A first filing there would need to tie a concrete mechanism, such as a closed-loop degassing sensor, to a defined cleaning outcome rather than restating the general cavitation-intensity approach already covered by earlier art.