Cooling Tower Patents: Top Companies & Filing Trends 2026
- Filings have cooled since the 2018 peak. 63 families were published that year; by the most recent full year the annual count had fallen back toward early-2017 levels, with no sign of a renewed climb through the midpoint year.
- Water treatment chemistry dominates the IPC mix. C02F accounts for 651 of the 1,005 records — nearly two-thirds — well ahead of heat-exchanger hardware (F28F, 383) and direct-contact exchange (F28C, 350).
- Filing is heavily China-weighted. 530 of the tracked records entered through the China receiving office, more than the next four offices — US, Japan, EPO and WIPO — combined.
A mature, chemistry-heavy field with a shrinking filing curve
Cooling tower and circulating water system patents sit at the intersection of direct-contact heat exchange hardware and water treatment chemistry. The dataset behind this page spans 1,005 patent families published between 2015 and mid-2026, drawn from records that combine cooling-tower terminology with treatment-specific language such as drift loss, fill fouling, approach to wet bulb and Legionella control. That search construction pulls in both the mechanical side of tower design and the chemical side of keeping circulating water clean and corrosion-free.
Filing activity peaked in 2018 at 63 families and has trended down since, with the midpoint year sitting well below that peak. Because publication typically lags filing by around 18 months, the last one or two years in any such trend understate true filing activity — but the broader shape, a rise through the late 2010s followed by a plateau or decline, is consistent enough across the window to read as a real slowdown rather than a data artefact.
Filing trend and technology composition
Two views of the same 1,005-family corpus: how filing volume has moved year over year, and how that volume splits across the IPC subclasses the search touches.
Annual filings, 2017–2026
Filings rose to a peak of 63 in 2018, sat near 38 at the 2022 midpoint, and had fallen to 5 by the most recent (partial) year — a pattern of decline rather than growth, even allowing for publication lag understating the final one to two years.
IPC subclass distribution
C02F (water and wastewater treatment) leads with 651 records, ahead of F28F heat-exchanger details (383) and F28C direct-contact heat exchange (350). Smaller counts in B01D separation (84), F28G surface cleaning (63), F24F air conditioning (54), C23F corrosion control (51) and F04D pumps (49) mark the field's secondary, more mechanical branches.
Shares are the percentage of the 1,005 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Cooling Tower and Circulating Water Systems with Eureka
This page is one run against one query. Ask Eureka your own question about cooling tower and circulating water systems and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited prior art in this corpus
SG11201609011UA — Method for adjusting concentration of cooling water treatment agent in circulating cooling water system
Filed by Kurita Water Industries, this application addresses a water recovery system that uses a separation membrane to treat blowdown discharge from a circulating cooling water system and return treated water to the loop. Its core claim covers controlling the concentration of the added cooling water treatment agent in the circulating system so that the membrane-based recovery stage can run at a higher, more stable water recovery rate without a corresponding rise in treatment cost.Filed 2016-12-29 · assignee Kurita Water Industries
View full record| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US4931187A | Cooling tower system | 142 |
| 2 | US5145585A | Method and apparatus for treating water in a cooling system | 128 |
| 3 | US20030127391A1 | Method for treatment of circulating cooling water | 83 |
| 4 | US5800732A | All-in-one treatment agent for cooling water | 79 |
| 5 | US4306967A | Cooling tower basin water treating apparatus | 79 |
| 6 | US5057229A | Apparatus and process for the treatment of cooling circuit water | 72 |
| 7 | US4464315A | Indexing controller system and method of automatic control of cooling water tower systems | 70 |
| 8 | CN1785853A | 一种无磷复合阻垢缓蚀剂及其在水处理中的应用 | 65 |
| 9 | US4172786A | Ozonation of cooling tower waters | 62 |
| 10 | US6733654B1 | Water treatment method and apparatus | 54 |
Citation counts reflect influence within this searched corpus and skew toward older filings — a high count signals a foundational reference, not current commercial relevance.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers say about this field
Four figures from the dataset that matter more for filing strategy than the headline family count.
The field has passed its filing peak
Annual filings ran to 63 families in 2018, had roughly halved by the 2022 midpoint at 38, and had fallen to 5 by the latest tracked year. Even discounting the most recent year or two for publication lag, the direction is down, not flat.
Water chemistry, not tower hardware, carries the volume
Almost two-thirds of records touch C02F water and wastewater treatment. Heat-exchanger hardware (F28F) and direct-contact exchange (F28C) trail well behind, meaning the densest claim space is in treatment agents and dosing methods, not tower structure.
China is the primary filing venue by a wide margin
China's receiving office accounts for more than half the corpus — well over the combined total for the US, Japan, EPO and WIPO offices. A freedom-to-operate check limited to Western jurisdictions will miss most of the active filing.
A handful of large groups file jointly at scale
The strongest co-assignee relationship in the dataset links a major Chinese petrochemical parent with its own research institute at 65 shared filings — far above the next pairs, which sit in the single digits. That gap points to one dominant internal filing structure rather than a broad web of external collaboration.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to cooling tower and circulating water systems, with the prior art for and against each one.
Who is filing, and where the field is still open
Filing in this space is dominated by a small number of large industrial and water-treatment groups, with momentum having cooled across the board in the most recent tracked year.
Sinopec and its research arms
Sinopec's corporate entity and its Beijing research institute form the strongest co-assignee pair in the dataset at 65 shared filings, reflecting a centralised group filing strategy across a large industrial operator. Momentum has flattened to zero in the latest tracked year across this group, consistent with the broader filing slowdown.
Kurita Water Industries
Kurita appears as the assignee on the representative record covering treatment-agent concentration control in membrane-based water recovery, and shows the same recent-year pause seen across the leaderboard.
Prime Datum and named inventor Rollins
Prime Datum Inc. co-files repeatedly with named inventor Patrick Rollins (7 and 6 shared filings across two name variants), a pattern typical of a smaller, founder-driven filer rather than a large corporate group. Its filing rate has dropped 100% year over year.
| Assignee | Recent year | YoY |
|---|---|---|
| China Petroleum & Chemical Corporation (Sinopec) | 0 | — |
| Sinopec Beijing Research Institute of Chemical Industry | 0 | — |
| PRIME DATUM INC | 0 | -100% |
| Kurita Water Industries Ltd. | 0 | — |
| McNNNAC Energy Services Inc. | 0 | — |
| Miura Co., Ltd. | 0 | — |
| Carrier Corporation (USA) | 0 | — |
| PRIME DATUM DEVELOPMENT CO LLC | 0 | — |
Where to take this next
The trend and leaderboard above answer who has filed and how much; the questions below go into specific claim scope and design-around options.
Map claim scope on the highest-cited prior art
The five most-cited records in this corpus, several dating to the 1980s and 1990s, still anchor citation chains in cooling tower water treatment. Checking current filings against their claim language is a faster filter than reading the full corpus.
Open key patentsCheck freedom-to-operate against the China-filed majority
With 530 of 1,005 records filed via China, a Western-only clearance search covers under half the active filing base in this field.
Review receiving officesAsk Eureka about a specific claim or assignee
For a claim-level read on SG11201609011UA, a design-around for Sinopec's dosing patents, or a first-claim draft in an under-claimed branch, put the question to Patsnap Eureka directly.
Ask EurekaCommon questions about cooling tower and circulating water patents
This dataset tracks 1,005 patent families published between 2015 and mid-2026 that combine cooling-tower terminology with water-treatment-specific language such as drift loss, fill fouling and Legionella control. The true global figure is higher because this is a filtered corpus built around a specific IPC and keyword combination, not every cooling-tower-related filing ever made. Families are the right unit to compare across companies because they neutralise repeat filing of the same invention across jurisdictions.
Filing is concentrated among large industrial groups with in-house water treatment operations, most visibly Sinopec's corporate entity alongside its Beijing research institute, which together form the strongest co-assignee relationship in the dataset at 65 shared filings. Kurita Water Industries and Prime Datum Inc. also appear as recurring filers, the latter alongside a named individual inventor rather than a broad corporate team. All of the top filers show zero or negative momentum in the latest tracked year, consistent with the overall filing slowdown.
It is slowing. Annual filings peaked at 63 in 2018, had fallen to roughly 38 by the 2022 midpoint, and dropped to 5 in the latest tracked year. Some of that final-year drop reflects the normal 18-month lag between filing and publication rather than a true collapse in activity, but the multi-year decline through 2022 predates that lag effect and points to a genuinely cooling filing curve.
Water and wastewater treatment chemistry, classified under IPC subclass C02F, accounts for 651 of the 1,005 records in this corpus — close to two-thirds of all filings. Heat-exchanger hardware details (F28F, 383 records) and direct-contact heat exchange design (F28C, 350) follow well behind, with smaller pockets in separation processes, surface cleaning, air conditioning integration, corrosion control and pumps. That distribution means dosing chemistry and treatment-agent claims are the most crowded part of the landscape, while pump integration and cleaning-surface mechanics see comparatively lighter filing.
The smaller IPC categories in this corpus — F28G surface cleaning (63 records), F24F air-conditioning integration (54) and F04D pumps (49) — carry noticeably lower filing density than the water-chemistry core, suggesting more room for a defensible first claim there. Specific under-claimed angles include real-time Legionella monitoring, sensor-based fill fouling detection, and non-chemical scale control methods, none of which show the same concentration of high-citation prior art as the treatment-agent core. Any white-space read should still be checked against a full claims search rather than the IPC counts alone, since subclass density is only a rough proxy for competitive crowding.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.