A static mixer (also called a motionless mixer) patent claims a fixed internal geometry — helical elements, baffles or lattice structures — that blends a fluid stream using the energy of flow rather than a moving impeller. In this dataset, that scope is captured mainly under IPC B01F (mixing and stirring, 14.3% of records) and B01J (chemical and physical processes, 15.2%). General mixing equipment patents that rely on rotating parts or external agitation fall outside this specific search and are not counted here. The distinction matters for freedom-to-operate work because static-mixer claims are usually tied to element geometry and pressure-drop or residence-time performance rather than motor or drive-train design.

The assignee ranking behind this dataset covers 100 companies, with the leader holding 707 records and the fifth-ranked filer at 383. The top five combined account for 2,698 records, or 13.5% of all 19,953 records in scope, and the top ten combined reach 4,013 records, or 20.1% — concentrated but not dominated by a single player. Beyond the ranked leaders there is a long tail of smaller and single-filing entrants, so a full freedom-to-operate check should not stop at the largest names. Sector mix in the ranking spans chemical majors, consumer-products companies and medical-device makers, reflecting how broadly static-mixer geometry gets reused across industries.

Filings rose to a peak of 883 in 2018 and have since eased; the clearest complete-year comparison shows 533 filings in 2021 falling to 392 in 2024, a -26% change. Years after 2024 in the raw trend look lower still, but publication typically lags actual filing by around 18 months, so 2025 and 2026 figures are still incomplete and should not be read as a continued decline. The honest reading is a contraction from the 2018 peak through 2024, with the very latest years too thin on data to call a trend either way. Anyone tracking this space should re-pull the trend periodically rather than treating the most recent year as final.