CPC technology class · F28

F28C - Heat-exchange Apparatus

Heat-exchange apparatus, not provided for in another subclass, in which the heat-exchange media come into direct contact without chemical interaction. 493 US utility patents granted 2015–2025, with the leading assignees and year-by-year grant trajectory.

Compiled by PlainPatent · May 15, 2026

493
US patents granted: #3/5
in F28: 2.3%
F28 class share: -6%
5-yr velocity

The verdict

According to USPTO PatentsView, Heat-exchange Apparatus ranks #545 of 670 CPC technology areas - 493 US patents granted since 2015, with recorded grant volume down 6% over five years.

#545
of 670 CPC technology areas: 493
US patents granted, 2015–2025: Baltimore Aircoil
leading assignee (30): -6%
grant velocity, last 5 yrs

How F28C's grant cadence moved

Between 2020–2024, F28C recorded 221 grants versus 235 in 2015–2019 (-6% equal-window velocity). Across complete years, output peaked in 2019 at 62 grants and bottomed in 2018 at 35 (+77% peak-over-trough). Lead assignee Baltimore Aircoil Company, Inc. holds 6.1% of the class ; the top three share 13.4%.

Leaderboard read

F28C concentration, lead at 6.1%

Baltimore Aircoil Company, Inc. leads this historical grant record at 6.1% of F28C - us corporation assignees hold 82% of class grants (183 of 224). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.

Leader's share: 6.1%
Top three share: 13.4%
Lead over #2: 11

Where F28C sits inside F28

Among 5 subclasses in F28 (Heat Exchange IN General), F28C ranks #3 and holds 2.3% of the parent class's 21,601 recorded grants. Sibling chips below are the other subclasses in the same parent class, not the nationwide volume/lead-share peers further down.

F28F 10,136 F28D 10,118 F28G 438 F28B 416

Rising assignees active in F28C

Company-wide grant multiples (2022–2024 vs 2019–2021) among assignees with ≥5 patents in this subclass. Growth is company-wide; class patent counts are subclass-specific.

#1 Energy and Environmental Research Center Foundation 4.40x 5 → 22 company-wide · 6 in F28C
#2 Brentwood Industries, Inc. 2.17x 6 → 13 company-wide · 7 in F28C
#3 Koch-Glitsch, LP 1.78x 9 → 16 company-wide · 5 in F28C
#4 Evapco, Inc. 1.20x 20 → 24 company-wide · 19 in F28C
#5 Ecovap, Inc. 1.20x 5 → 6 company-wide · 7 in F28C

F28C grants by year, peak 2019 (62)

US utility-patent grants per year in F28C, 2015–2025 - recent five years are down 6% versus 2015–2019.

Baltimore Aircoil

30
Evapco

19
Spx Cooling

17
The Chemours Fc

10
Sdcmaterials

9
Prime Datum

8
Brentwood Industries

7
Prime Datum Developmen…

7
Ecovap

7
Energy and Environment…

6
Koch-glitsch

5
Booz Allen Hamilton

4

What this shows Baltimore Aircoil is the most active filer in F28C, holding 30 of the 493 patents in this class. Concentration at the top signals how contestable this technology area is for new entrants.

View data table

Top patent holders in CPC subclass F28C
Rank	Company	Patents in F28C
#1	Baltimore Aircoil Company, Inc.	30
#2	Evapco, Inc.	19
#3	SPX Cooling Technologies, Inc.	17
#4	THE Chemours Company FC, LLC	10
#5	SDCmaterials, Inc.	9
#6	Prime Datum, Inc.	8
#7	Brentwood Industries, Inc.	7
#8	Prime Datum Development Company, LLC	7
#9	Ecovap, Inc.	7
#10	Energy and Environmental Research Center Foundation	6
#11	Koch-Glitsch, LP	5
#12	Booz Allen Hamilton Inc.	4
#13	OVH	4
#14	Gradiant Corporation	4
#15	Heatcraft Refrigeration Products LLC	3
#16	Inertech IP LLC	3
#17	Oy Halton Group Ltd.	3
#18	Ensyn Renewables, Inc.	3
#19	Munters Corporation	3
#20	Dri-steem Corporation	3

Footprint here vs. claim strategy

Each dot is a leading F28C assignee, placed by how many patents it holds in this class (horizontal) against its company-wide average claims per patent (vertical) - a read on whether the class is led by broad-but-shallow filers or focused deep-claim players.

Top 14 F28C assignees by class footprint. Bubble size = patents in F28C. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Questions about F28C

Which company holds the most patents in F28C?

Baltimore Aircoil Company, Inc. leads F28C with 30 patents (6.1% of the subclass). By PatentsView assignee type, us corporations account for 82% of class grants.

Which F28C assignees grew fastest recently?

Among assignees with ≥5 grants in F28C, Energy and Environmental Research Center Foundation shows the highest company-wide grant multiple (4.40x: 5 grants in 2019–2021 → 22 in 2022–2024) while holding 6 patents in this subclass. Growth is company-wide, not class-only.

How does F28C compare inside parent class F28?

Inside F28 (Heat Exchange IN General), F28C ranks #3 of 5 subclasses by grant volume and holds 2.3% of the parent class total. The largest sibling is F28F (10,136 grants).

What to do with this data

F28C in context - here's where to go next.

Baltimore Aircoil Company, Inc. leads F28C with 30 grants in this class. See full portfolio
F28C ranks #545 of 670 by grant volume among all tracked CPC technology areas. See the ranking
Inside parent class F28, the largest sibling subclass is F28F with 10,136 grants. Explore F28F

Figures reflect USPTO PatentsView grant data through 2026-05-15; pending applications not yet granted are not counted.

Methodology - F28C figures are USPTO PatentsView granted-utility totals for this subclass (493 grants in the tracked window).

Every figure on PlainPatent is rendered directly from USPTO source data, no number is typed in by an editor. This page draws directly on USPTO source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.