Filing in this field is concentrated at the top: the leading assignee alone accounts for 99 of the 270 records in scope, and the top five combined account for 180 records, or 66.7% of the field. The top ten combined reach 224 records, or 83.0%. This means a small number of established refrigeration and transport-equipment companies hold the majority of claim space, while a long tail of smaller entrants files far less frequently.

Filings peaked at 23 in 2019 after rising from 18 in 2017, then declined; by 2024, the last year that can be treated as complete, annual filing had dropped to 0 from 1 in 2021, a -100% move over that three-year span. However, publication lags filing by roughly 18 months, so the 2025 and 2026 figures shown in any trend chart are still incomplete and should not be read as evidence the field has stopped moving. A clearer read on the most recent activity will only be available once those years finish publishing.

Start with F25D (refrigerators and cooling), which covers 90.4% of the 270 records in scope, and F25B (refrigeration and heat pumps) at 31.9% — together these define the refrigeration-hardware core. For transport-specific integration, add B60H (vehicle heating and air-conditioning, 29.3%) and the container/load-handling classes B60P and B65D (14.1% each); food-condition-specific claims tend to sit in A23B or A23L, each under 10% of records.

US5924302A, an insulated shipping container patent cited 189 times, is the most-cited record in this dataset and represents foundational claim territory that a large share of later container-design patents had to file around. It does not itself list the specific monitoring or sensor logic that later patents build on top of the container structure. Any new entrant designing an insulated refrigerated container should expect to review this and the other high-citation records (each cited 100+ times) before finalizing a structural claim, since these older patents underlie much of what followed.

The thinnest technology bands in this dataset are food-condition monitoring (A23B at 9.6%, A23L at 6.7% of the 270 records) and material-handling integration (B65G at 6.3%), all well below the 90.4% and 31.9% shares held by the core refrigeration classes F25D and F25B. This gap suggests that claims tying sensor-detected cargo condition directly to automated refrigeration-loop control are comparatively underclaimed. With only 10 co-assignee pairs recorded across the whole dataset, cross-disciplinary filing between food science and refrigeration engineering also appears rare, reinforcing that this intersection is open ground rather than saturated.