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 grant trajectory.

238
US patents granted
#2/3
in F22
10.0%
F22 class share
-18%
5-yr velocity

The verdict

According to USPTO PatentsView, Preheating ranks #592 of 670 CPC technology areas - 238 US patents granted since 2015, with recorded grant volume down 18% over five years.

#592
of 670 CPC technology areas
238
US patents granted, 2015–2025
General Electric
leading assignee (14)
-18%
grant velocity, last 5 yrs

How F22D's grant cadence moved

Between 2020–2024, F22D recorded 103 grants versus 126 in 2015–2019 (-18% equal-window velocity). Across complete years, output peaked in 2019 at 34 grants and bottomed in 2024 at 17 (+100% peak-over-trough). Lead assignee Mitsubishi Power, Ltd. holds 2.9% of the class ; the top three share 8.0%.

Leaderboard read

F22D concentration, lead at 2.9%

Mitsubishi Power, Ltd. leads this historical grant record at 2.9% of F22D - us corporation assignees hold 52% of class grants (34 of 65). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.

Leader's share
2.9%

7 of 238 grants

Top three share
8.0%

of the class's recorded grants

Lead over #2
1

more grants than The Babcock & Wilcox Company

Where F22D sits inside F22

Among 3 subclasses in F22 (Steam Generation), F22D ranks #2 and holds 10.0% of the parent class's 2,387 recorded grants. Sibling chips below are the other subclasses in the same parent class, not the nationwide volume/lead-share peers further down.

F22B 1,959 F22G 190

Rising assignees active in F22D

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 Mitsubishi Power, Ltd. 0.66x 133 → 88 company-wide · 7 in F22D
  2. #2 The Babcock & Wilcox Company 0.28x 18 → 5 company-wide · 6 in F22D

F22D grants by year, peak 2019 (34)

US utility-patent grants per year in F22D, 2015–2025 - recent five years are down 18% 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

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). 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-geraeteb…Echogen Power SystemsDri-steemMitsubishi Hitachi…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).

Questions about F22D

Which company holds the most patents in F22D?
General Electric Company leads F22D with 14 patents (2.9% of the subclass). By PatentsView assignee type, us corporations account for 52% of class grants.
Which F22D assignees grew fastest recently?
Among assignees with ≥5 grants in F22D, Mitsubishi Power, Ltd. shows the highest company-wide grant multiple (0.66x: 133 grants in 2019–2021 → 88 in 2022–2024) while holding 7 patents in this subclass. Growth is company-wide, not class-only.
How does F22D compare inside parent class F22?
Inside F22 (Steam Generation), F22D ranks #2 of 3 subclasses by grant volume and holds 10.0% of the parent class total. The largest sibling is F22B (1,959 grants).

What to do with this data

F22D in context - here's where to go next.

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

Methodology - F22D figures are USPTO PatentsView granted-utility totals for this subclass (238 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.