PlainPatent

CPC technology class · F28

F28D - Heat-exchange Apparatus

Heat-exchange apparatus, not provided for in another subclass, in which the heat-exchange media do not come into direct contact. 10,118 US utility patents granted 2015–2025, with the leading assignees and year-by-year grant trajectory.

10,118
US patents granted
#2/5
in F28
46.8%
F28 class share
+14%
5-yr velocity

The verdict

According to USPTO PatentsView, Heat-exchange Apparatus ranks #170 of 670 CPC technology areas - 10,118 US patents granted since 2015, with recorded grant volume up 14% over five years.

#170
of 670 CPC technology areas
10,118
US patents granted, 2015–2025
Mitsubishi Electric
leading assignee (234)
+14%
grant velocity, last 5 yrs

How F28D's grant cadence moved

Between 2020–2024, F28D recorded 4,796 grants versus 4,224 in 2015–2019 (+14% equal-window velocity). Across complete years, output peaked in 2019 at 1,162 grants and bottomed in 2015 at 598 (+94% peak-over-trough). Lead assignee Hamilton Sundstrand Corporation (HSC) holds 2.2% of the class ; the top three share 5.5%.

Leaderboard read

F28D concentration, lead at 2.2%

Hamilton Sundstrand Corporation (HSC) leads this historical grant record at 2.2% of F28D - foreign corporation assignees hold 59% of class grants (2,794 of 4,721). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.

Leader's share
2.2%

227 of 10,118 grants

Top three share
5.5%

of the class's recorded grants

Lead over #2
40

more grants than Mahle International GmbH

Where F28D sits inside F28

Among 5 subclasses in F28 (Heat Exchange IN General), F28D ranks #2 and holds 46.8% 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 F28C 493 F28G 438 F28B 416

Rising assignees active in F28D

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. #1 Fulian Precision Electronics (Tianjin) Co., Ltd. 118x 0 → 118 company-wide · 5 in F28D
  2. #2 Rondo Energy, Inc. 36x 0 → 36 company-wide · 42 in F28D
  3. #3 Zhejiang Dunan Artificial Environment Co., Ltd. 23x 0 → 23 company-wide · 11 in F28D
  4. #4 Vast Glory Electronics & Hardware & Plastic (HUI ZHOU) Ltd. 10x 2 → 20 company-wide · 13 in F28D
  5. #5 Trucapsol LLC 10x 1 → 10 company-wide · 5 in F28D

F28D grants by year, peak 2019 (1,162)

US utility-patent grants per year in F28D, 2015–2025 - recent five years are up 14% versus 2015–2019.

4006008001,0001,200 20152016201720182019202020212022202320242025 646

Who leads F28D?

The 12 most active assignees in Heat-exchange Apparatus, NOT Provided FOR IN Another Subclass, IN Which THE Heat-exchange Media DO NOT Come Into Direct Contact - wider bars mean more grants

patents

What this shows Mitsubishi Electric is the most active filer in F28D, holding 234 of the 10,118 patents in this class. Concentration at the top signals how contestable this technology area is for new entrants.

Source USPTO PatentsView, granted utility patents As of 2015–2025 grant years
View data table
Top patent holders in CPC subclass F28D
Rank Company Patents in F28D
#1 Hamilton Sundstrand Corporation (HSC) 227
#2 Mahle International GmbH 187
#3 Asia Vital Components Co., Ltd. 146
#4 Hanon Systems 123
#5 Daikin Industries, Ltd. 113
#6 Carrier Corporation 109
#7 Valeo Systemes Thermiques 101
#8 Alfa Laval Corporate AB 99
#9 Dana Canada Corporation 92
#10 Modine Manufacturing Company 87
#11 Cooler Master Co., Ltd. 72
#12 Trane International Inc. 63
#13 Denso International America, Inc. 60
#14 Johnson Controls Technology Company 52
#15 Furukawa Electric Co., Ltd. 51
#16 Shinko Electric Industries Co., Ltd. 49
#17 Kyungdong Navien Co., Ltd. 42
#18 Rondo Energy, Inc. 42
#19 Rheem Manufacturing Company 38
#20 Sanhua (HANGZHOU) Micro Channel Heat Exchanger Co., Ltd. 38

Footprint here vs. claim strategy

Each dot is a leading F28D 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 F28D assignees by class footprint. Bubble size = patents in F28D. Source: USPTO PatentsView (claim depth is company-wide across all classes). Scatter plot of 14 data points (bubble-sized by third dimension). 5101520 050100150200250 Patents in F28D Avg claims / patent (company-wide) Hamilton Sundstrand…Mahle InternationalAsia Vital ComponentsHanon SystemsDaikin IndustriesCarrierValeo Systemes…Alfa Laval Corporate…Dana CanadaModine ManufacturingCooler MasterTrane InternationalDenso International…Johnson Controls…
Top 14 F28D assignees by class footprint. Bubble size = patents in F28D. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Classes near F28D's 10,118-grant footprint

Nationwide nearest neighbors for F28D (#170 of 670 by volume ; lead share 2.3%) - not the F28 parent-class siblings above.

Nearest by grant volume

F16F 10,113 F28F 10,136 A01K 10,071 H04Q 10,225

Nearest by lead-assignee share

F04B 2.3% G01D 2.3% G01R 2.3% B22D 2.3%

Questions about F28D

Which company holds the most patents in F28D?
Mitsubishi Electric Corporation leads F28D with 234 patents (2.2% of the subclass). By PatentsView assignee type, foreign corporations account for 59% of class grants.
Which F28D assignees grew fastest recently?
Among assignees with ≥5 grants in F28D, Fulian Precision Electronics (Tianjin) Co., Ltd. shows the highest company-wide grant multiple (118x: 0 grants in 2019–2021 → 118 in 2022–2024) while holding 5 patents in this subclass. Growth is company-wide, not class-only.
How does F28D compare inside parent class F28?
Inside F28 (Heat Exchange IN General), F28D ranks #2 of 5 subclasses by grant volume and holds 46.8% of the parent class total. The largest sibling is F28F (10,136 grants).

What to do with this data

F28D in context - here's where to go next.

  • Hamilton Sundstrand Corporation (HSC) leads F28D with 227 grants in this class. See full portfolio
  • F28D ranks #170 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 - F28D figures are USPTO PatentsView granted-utility totals for this subclass (10,118 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.