A catalytic bead sensor, also called a pellistor, detects combustible gas by measuring the heat released when the gas oxidises on a catalyst-coated bead held at an elevated temperature. The temperature rise changes the electrical resistance of the bead, which is measured against a reference element to produce a signal proportional to gas concentration. The design has been in commercial use for decades, and most current patent activity addresses failure modes like catalyst poisoning and signal drift rather than the core sensing principle itself.

Filing in this dataset is concentrated: the top five assignees hold 262 of 473 records in scope, or 55.4%, and the top ten extend that to 67.2%. The leading assignee alone holds 142 records, well ahead of the fifth-place figure of 16. Below that leader group sits a long tail of companies with far fewer filings each, so competitive attention should focus on the concentrated top rather than treating the field as evenly distributed.

Filing peaked in 2020 at 56 records and declined to 9 by 2024, a 36% drop over that three-year span. Figures for 2025 and 2026 show even lower counts, but publication typically lags filing by around 18 months, so those recent years are undercounted and should not be read as proof the technology has stopped attracting investment. The more defensible reading is that filing has cooled from its 2020 peak, with the most recent trend still uncertain.