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CPC technology class · F28

F28F - Details Of Heat-exchange And Heat-transfer Apparatus

Details of heat-exchange and heat-transfer apparatus, of general application. 10,136 US utility patents granted 2015–2025, with the leading assignees and year-by-year grant trajectory.

10,136
US patents granted
#1/5
in F28
46.9%
F28 class share
+7%
5-yr velocity

The verdict

According to USPTO PatentsView, Details Of Heat-exchange And Heat-transfer Apparatus ranks #169 of 670 CPC technology areas - 10,136 US patents granted since 2015, with recorded grant volume up 7% over five years.

#169
of 670 CPC technology areas
10,136
US patents granted, 2015–2025
Hamilton Sundstrand (Hsc)
leading assignee (273)
+7%
grant velocity, last 5 yrs

How F28F's grant cadence moved

Between 2020–2024, F28F recorded 4,693 grants versus 4,393 in 2015–2019 (+7% equal-window velocity). Across complete years, output peaked in 2019 at 1,197 grants and bottomed in 2015 at 630 (+90% peak-over-trough). Lead assignee Hamilton Sundstrand Corporation (HSC) holds 2.7% of the class ; the top three share 6.0%.

Leaderboard read

F28F concentration, lead at 2.7%

Hamilton Sundstrand Corporation (HSC) leads this historical grant record at 2.7% of F28F - foreign corporation assignees hold 61% of class grants (2,838 of 4,667). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.

Leader's share
2.7%

273 of 10,136 grants

Top three share
6.0%

of the class's recorded grants

Lead over #2
66

more grants than Mahle International GmbH

Where F28F sits inside F28

Among 5 subclasses in F28 (Heat Exchange IN General), F28F ranks #1 and holds 46.9% 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.

F28D 10,118 F28C 493 F28G 438 F28B 416

Rising assignees active in F28F

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 Zhejiang Dunan Artificial Environment Co., Ltd. 23x 0 → 23 company-wide · 12 in F28F
  2. #2 Vast Glory Electronics & Hardware & Plastic (HUI ZHOU) Ltd. 10x 2 → 20 company-wide · 11 in F28F
  3. #3 Frore Systems Inc. 9.75x 4 → 39 company-wide · 9 in F28F
  4. #4 Johnson Controls Tyco IP Holdings LLP 9.57x 67 → 641 company-wide · 14 in F28F
  5. #5 Nelumbo Inc. 8.00x 1 → 8 company-wide · 11 in F28F

F28F grants by year, peak 2019 (1,197)

US utility-patent grants per year in F28F, 2015–2025 - recent five years are up 7% versus 2015–2019.

4006008001,0001,2001,400 20152016201720182019202020212022202320242025 616

Who leads F28F?

The 12 most active assignees in Details OF Heat-exchange AND Heat-transfer Apparatus, OF General Application - wider bars mean more grants

patents

What this shows Hamilton Sundstrand… is the most active filer in F28F, holding 273 of the 10,136 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 F28F
Rank Company Patents in F28F
#1 Hamilton Sundstrand Corporation (HSC) 273
#2 Mahle International GmbH 207
#3 Hanon Systems 129
#4 Daikin Industries, Ltd. 124
#5 Valeo Systemes Thermiques 115
#6 Carrier Corporation 114
#7 Alfa Laval Corporate AB 107
#8 Asia Vital Components Co., Ltd. 106
#9 Dana Canada Corporation 106
#10 Modine Manufacturing Company 88
#11 Cooler Master Co., Ltd. 67
#12 Denso International America, Inc. 66
#13 Trane International Inc. 66
#14 Uacj Corporation 48
#15 Rheem Manufacturing Company 44
#16 Sanhua (HANGZHOU) Micro Channel Heat Exchanger Co., Ltd. 43
#17 Kyungdong Navien Co., Ltd. 42
#18 Furukawa Electric Co., Ltd. 38
#19 Linde GmbH 37
#20 Baltimore Aircoil Company, Inc. 37

Footprint here vs. claim strategy

Each dot is a leading F28F 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 F28F assignees by class footprint. Bubble size = patents in F28F. Source: USPTO PatentsView (claim depth is company-wide across all classes). Scatter plot of 14 data points (bubble-sized by third dimension). 681012141618 050100150200250300 Patents in F28F Avg claims / patent (company-wide) Hamilton Sundstrand…Mahle InternationalHanon SystemsDaikin IndustriesValeo Systemes…CarrierAlfa Laval Corporate…Asia Vital ComponentsDana CanadaModine ManufacturingCooler MasterDenso International…Trane InternationalUacj
Top 14 F28F assignees by class footprint. Bubble size = patents in F28F. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Classes near F28F's 10,136-grant footprint

Nationwide nearest neighbors for F28F (#169 of 670 by volume ; lead share 2.7%) - not the F28 parent-class siblings above.

Nearest by grant volume

F28D 10,118 F16F 10,113 A01K 10,071 H04Q 10,225

Nearest by lead-assignee share

A23P 2.7% E03F 2.7% B29K 2.7% G16H 2.7%

Questions about F28F

Which company holds the most patents in F28F?
Hamilton Sundstrand Corporation (HSC) leads F28F with 273 patents (2.7% of the subclass). By PatentsView assignee type, foreign corporations account for 61% of class grants.
Which F28F assignees grew fastest recently?
Among assignees with ≥5 grants in F28F, Zhejiang Dunan Artificial Environment Co., Ltd. shows the highest company-wide grant multiple (23x: 0 grants in 2019–2021 → 23 in 2022–2024) while holding 12 patents in this subclass. Growth is company-wide, not class-only.
How does F28F compare inside parent class F28?
Inside F28 (Heat Exchange IN General), F28F ranks #1 of 5 subclasses by grant volume and holds 46.9% of the parent class total. The largest sibling is F28D (10,118 grants).

What to do with this data

F28F in context - here's where to go next.

  • Hamilton Sundstrand Corporation (HSC) leads F28F with 273 grants in this class. See full portfolio
  • F28F ranks #169 of 670 by grant volume among all tracked CPC technology areas. See the ranking
  • Inside parent class F28, the largest sibling subclass is F28D with 10,118 grants. Explore F28D

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

Methodology - F28F figures are USPTO PatentsView granted-utility totals for this subclass (10,136 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.