PlainPatent

CPC technology class · F22

F22D - Preheating

Preheating, or accumulating preheated, feed-water for steam generation; feed-water supply for steam generation; controlling water level for steam generation; auxiliary devices for promoting water circulation within steam boilers. 238 US utility patents granted 2015–2025, with the leading assignees and year-by-year filing trajectory.

238
US patents granted
F22
Parent CPC class
20
Active assignees
-14%
5-yr velocity

The verdict

Preheating ranks #591 of 670 CPC technology areas - 238 US patents granted since 2015, with filing down 14% over five years.

#591
of 670 CPC technology areas
238
US patents granted, 2015–2025
General Electric
leading assignee (14)
-14%
filing velocity, last 5 yrs
Top assignee: General Electric Company (14 patents)

CPC subclass F22D - PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER FOR STEAM GENERATION; FEED-WATER SUPPLY FOR STEAM GENERATION; CONTROLLING WATER LEVEL FOR STEAM GENERATION; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN STEAM BOILERS - covers 238 US utility patents granted between 2015 and 2025 according to USPTO PatentsView records, within the broader CPC class F22 (STEAM GENERATION). See our CPC classification guide for how the system works.

The competitive landscape in F22D is shaped by 20 distinct companies actively filing in this space. General Electric Company leads with 14 patents, followed by The Babcock & Wilcox Company at 6 grants and Skavis Corporation at 6.

Filing activity in F22D is down 14% over the past five years versus 2015-2019, a relatively steady filing pace. All counts come directly from USPTO PatentsView and reflect US granted utility patents only.

Is F22D innovation accelerating?

US utility-patent grants per year in F22D, 2015–2025 - recent five years are down 14% versus 2015–2019.

010203040 20152016201720182019202020212022202320242025 5

Who leads F22D?

The 12 most active assignees in PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER FOR STEAM GENERATION; FEED-WATER SUPPLY FOR STEAM GENERATION; CONTROLLING WATER LEVEL FOR STEAM GENERATION; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN STEAM BOILERS - wider bars mean more grants

patents

What this shows General Electric is the most active filer in F22D, holding 14 of the 238 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 F22D
Rank Company Patents in F22D
#1 Mitsubishi Power, Ltd. 7
#2 The Babcock & Wilcox Company 6
#3 Skavis Corporation 6
#4 Nooter/eriksen, Inc. 4
#5 TLV Co., Ltd. 3
#6 Miura Co., Ltd. 3
#7 Arvos Ljungstrom Llc 3
#8 E.g.o. Elektro-geraetebau Gmbh 2
#9 Echogen Power Systems, Llc 2
#10 Dri-steem Corporation 2
#11 Mitsubishi Hitachi Power Systems Americas, Inc. 2
#12 FCCL Partnership 2
#13 Abengoa Solar New Technologies, S.a. 1
#14 Watts Water Technologies 1
#15 XDI Holdings, Llc 1
#16 Orcan Energy Ag 1
#17 Sumitomo SHI FW Energia Oy 1
#18 Lochinvar, Llc 1
#19 Rancilio Group S.p.a. 1
#20 Netzsch Trockenmahltechnik Gmbh 1

About This Class

CPC subclass F22D belongs to class F22.

238 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 F22D 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 F22D assignees by class footprint. Bubble size = patents in F22D. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Top 14 F22D assignees by class footprint. Bubble size = patents in F22D. Source: USPTO PatentsView (claim depth is company-wide across all classes). Scatter plot of 14 data points (bubble-sized by third dimension). 051015202530 02468 Patents in F22D Avg claims / patent (company-wide) Mitsubishi PowerThe Babcock & WilcoxSkavisNooter/EriksenTlvMiuraArvos LjungstromE G O Elektro-geraete…Echogen Power SystemsDri-steemMitsubishi Hitachi Po…Fccl PartnershipAbengoa Solar NewWatts Water
Top 14 F22D assignees by class footprint. Bubble size = patents in F22D. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Frequently Asked Questions

What is CPC class F22D?
CPC subclass F22D covers PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER FOR STEAM GENERATION; FEED-WATER SUPPLY FOR STEAM GENERATION; CONTROLLING WATER LEVEL FOR STEAM GENERATION; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN STEAM BOILERS. It belongs to CPC class F22 (STEAM GENERATION), with 238 US utility patents granted since 2015.
How many patents have been filed in F22D?
238 US utility patents were granted in CPC subclass F22D between 2015 and 2025, based on USPTO PatentsView data.
Which company holds the most patents in F22D?
General Electric Company leads F22D with 14 patents, making it the most active assignee in this technology area.
How is patent data for F22D 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., F22) is a broad technology category. Subclasses like F22D 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.