The top five assignees together hold 35.2% of the 352 records in scope, and the top ten reach 50.6%. That means roughly half the field sits outside the ten most active filers, spread across ninety more ranked assignees and unranked entrants. The leader alone holds 31 records versus 21 at fifth place, so within the top group there is a clear front-runner rather than a tight cluster. For a new entrant, this points to a field where broad freedom-to-operate exists but the leading player’s claims deserve specific scrutiny.

Filing peaked in 2019 at 29 records and has since settled into a plateau: the 2021-to-2024 comparison shows 17 down to 16, a -6% change over three years. That is a flattening, not a collapse. The 2025 and 2026 figures in any such dataset are understated because patent publication typically lags actual filing by around eighteen months, so recent years will fill in as more applications publish.

B01D, covering separation processes such as filtration, appears in 60.2% of the 352 records and is by far the dominant class. B01J (chemical and physical processes, including catalysis) follows at 17.9%, and C01B (non-metallic elements and inorganic compounds) at 8.8%. Smaller classes including C07F, F25J, C12M, C07C and C12P each sit under 9%, meaning the field is still framed mostly as separation-process hardware rather than as gas-liquefaction, bioreactor, or fermentation equipment. Because a single record can carry several IPC classes, these shares add up to more than 100% of the total.