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 filing trajectory.

10,118
US patents granted
F28
Parent CPC class
20
Active assignees
+29%
5-yr velocity

The verdict

Heat-exchange Apparatus ranks #170 of 670 CPC technology areas - 10,118 US patents granted since 2015, with filing up 29% over five years.

#170
of 670 CPC technology areas
10,118
US patents granted, 2015–2025
Mitsubishi Electric
leading assignee (234)
+29%
filing velocity, last 5 yrs
Top assignee: Mitsubishi Electric Corporation (234 patents)

CPC subclass F28D - HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT - covers 10,118 US utility patents granted between 2015 and 2025 according to USPTO PatentsView records, within the broader CPC class F28 (HEAT EXCHANGE IN GENERAL). See our CPC classification guide for how the system works.

The competitive landscape in F28D is shaped by 20 distinct companies actively filing in this space. Mitsubishi Electric Corporation leads with 234 patents, followed by Mahle International Gmbh at 187 grants and ASIA Vital Components Co., Ltd. at 146.

Filing activity in F28D is up 29% over the past five years versus 2015-2019, a sharp acceleration suggesting an emerging or fast-moving technology area. All counts come directly from USPTO PatentsView and reflect US granted utility patents only.

Is F28D innovation accelerating?

US utility-patent grants per year in F28D, 2015–2025 - recent five years are up 29% 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

About This Class

CPC subclass F28D belongs to class F28.

10,118 patents were granted in this class between 2015 and 2025.

20 companies actively patent in this space.

Classification System

Cooperative Patent Classification (CPC) is a hierarchical patent classification system used by the USPTO and EPO.

← All Technology Classes Technology Rankings →

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).

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 Thermi…Alfa Laval Corporate…Dana CanadaModine ManufacturingCooler MasterTrane InternationalDenso International A…Johnson Controls Tech…
Top 14 F28D assignees by class footprint. Bubble size = patents in F28D. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Frequently Asked Questions

What is CPC class F28D?
CPC subclass F28D covers HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT. It belongs to CPC class F28 (HEAT EXCHANGE IN GENERAL), with 10,118 US utility patents granted since 2015.
How many patents have been filed in F28D?
10,118 US utility patents were granted in CPC subclass F28D between 2015 and 2025, based on USPTO PatentsView data.
Which company holds the most patents in F28D?
Mitsubishi Electric Corporation leads F28D with 234 patents, making it the most active assignee in this technology area.
How is patent data for F28D collected?
Patent data comes from USPTO PatentsView, a public research dataset maintained by the United States Patent and Trademark Office. It covers all US granted utility patents and assigns CPC codes based on the technology described in each patent.
What is the difference between CPC class and subclass?
A CPC class (e.g., F28) is a broad technology category. Subclasses like F28D provide finer granularity within that category. PlainPatent organizes data at the subclass level (4-character codes) for the most useful view of technology domains.

Read our methodology - how this data is sourced, computed, and verified.

Data sourced from USPTO PatentsView - official U.S. government patent data. See our methodology for computation details. Retrieved and formatted by PlainPatent Editorial

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.