Reciprocating Compressor Materials Patents: Leaders & White Space 2026
- Filing has cooled since 2019. Filings peaked at 7 in 2019 and had fallen back to 2 by the 2022 midpoint, pointing to a mature, occupied claim space rather than an expanding one.
- Positive-displacement pump art dominates. F04B accounts for 114 of 226 records — half the corpus — with piston/seal art (F16J) and rotary-piston art (F04C) as the next largest but much smaller pools.
- Ownership is fragmented, not consolidated. No single assignee shows sustained recent-year momentum; several tracked assignees, including Whirlpool and LG Electronics, sit at zero filings in the latest year.
What this landscape covers
This landscape tracks patent families at the intersection of reciprocating and piston compressors and the materials engineered into their valves, cylinders and seals: wear-resistant cylinder coatings, self-lubricating pistons and rings, and valve-specific material claims. The 226-family corpus spans filings from 2015 through the current data cut-off, with publication lagging filing by roughly 18 months, so the last one to two years understate real filing activity.
The dataset draws on TACD search across compressor and material terms, ranked by patent family to neutralise repeat filings across jurisdictions. Receiving-office data shows the United States and Europe as the two largest filing destinations, with Japan, WIPO/PCT, Canada and Germany forming a secondary tier.
Filing trend and technology composition
Two views of the same 226-family corpus: how filing volume has moved year over year, and which IPC subclasses hold the claim density.
A flat-to-declining filing curve
Filings rose from 2 in 2017 to a peak of 7 in 2019, then eased back to 2 by 2022. That pattern — a short run-up followed by a plateau — is more consistent with a niche that reached its claim ceiling than one still being actively opened up. The final one to two years of any such trend are always undercounted because of publication lag, so treat the most recent bars as a floor, not a ceiling.
F04B carries half the corpus
F04B (positive-displacement pumps) alone accounts for 114 of 226 records, roughly half the dataset. F16J (pistons, seals and gaskets) and F04C (rotary-piston pumps) follow at 37 and 36 respectively, with lubricant-specific classes C10M and C10N together contributing 48 records. F16K (valves) sits at 23 — smaller than the pump and piston classes, which is notable given the search string explicitly targets valve materials.
Shares are the percentage of the 226 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Reciprocating Compressor Advanced Materials with Eureka
This page is one run against one query. Ask Eureka your own question about reciprocating compressor advanced materials and every answer comes back with the patent numbers behind it.
Try EurekaThe documents anchoring this field
EP0400334A2 — Oilless reciprocating compressor and expansion apparatus
A piston movable in a metal cylinder of an oilless reciprocating compressor comprises a piston body fitted with a piston ring made of self-lubricating material. The piston body is made, fully or on its circumferential surface, of self-lubricating material without compromising durability under compression heat at the piston top. A ring groove shaped like the letter C, with ends spaced apart, may be formed in the piston's self-lubricating surface.Filed by Iwata Air Compressor Mfg. Co., Ltd., 1990-12-05.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5121607A | Energy recovery system for large motor vehicles | 185 |
| 2 | US5033940A | Reciprocating high-pressure compressor piston with annular clearance | 103 |
| 3 | US3931554A | Reciprocating motor-compressor system | 68 |
| 4 | US5195881A | Screw-type compressor/expander with valves at each axial end of rotors | 57 |
| 5 | US8496026B2 | Valve | 56 |
| 6 | US20130276917A1 | Valve Design | 55 |
| 7 | US6302665B1 | Hermetic compressor and open compressor | 47 |
| 8 | US6309194B1 | Enhanced oil film dilation for compressor suction valve stress reduction | 46 |
| 9 | EP0679809A2 | Compressor and refrigerating unit | 41 |
| 10 | US5775885A | Combination suction manifold and cylinder block for a reciprocating compressor | 38 |
Citation counts favour older filings simply because they have had longer to accumulate citations inside the searched corpus; read them as a signal of influence on later filers, not as a ranking of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers mean for a filing decision
Three signals stand out once the trend, the IPC mix and the citation graph are read together.
The growth phase has already passed
The corpus peaked in 2019 and has not returned to that level since. A declining or flat midpoint after a peak usually means the obvious material and geometry combinations are already claimed, and new entrants need a genuinely different mechanism to clear prior art rather than an incremental variant.
Half the field sits in one subclass
F04B's share means most material innovation has been filed as part of pump/compressor structure claims rather than as standalone valve or coating patents. That skews design-around risk toward broad structural claims, not narrow material-composition ones.
Influence sits with early, broad filings
The most-cited record in the set (US5121607A) predates most of the corpus and covers energy recovery rather than a specific material. High citation counts here reflect age and foundational scope, not that the underlying claims are still the ones worth designing around today.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to reciprocating compressor advanced materials, with the prior art for and against each one.
Who is filing, and who has gone quiet
Assignee activity in this corpus is fragmented: co-filing pairs exist but no single organisation shows sustained recent output.
A small collaborative cluster around Shin Jin Ung
The strongest co-assignee links in the dataset — Shin Jin Ung with Lee Kangwook, Lee Geun Hyoung and Kwon Yongchol, each at 11 shared filings — point to a single collaborative group rather than a corporate R&D pipeline, distinct from the larger listed assignees.
Established names have stopped filing in this niche
Whirlpool, LG Electronics, Nordson Piginno Holdings, Entropie, voestalpine Precision Strip and ManSpring Energy all show zero filings in the latest tracked year, one with a -100% year-on-year change. That is consistent with a niche where large compressor makers filed early and have since moved on or folded the art into broader filings.
US and Europe carry the bulk of filings
The United States (61) and the European Patent Office (44) are the two largest receiving offices, together holding well over a third of tracked filings ahead of Japan (23), WIPO/PCT (19), Canada (16) and Germany (11).
| Assignee | Recent year | YoY |
|---|---|---|
| Nordson Piginno Holdings | 0 | — |
| Entropie Ltd. | 0 | — |
| LG Electronics | 0 | — |
| voestalpine Precision Strip | 0 | — |
| ManSpring Energy Co., Ltd. | 0 | -100% |
| Whirlpool Corporation | 0 | — |
| SHIN JIN UNG | 0 | — |
| LEE KANGWOOK | 0 | — |
Where to take this analysis
The dataset points to a mature, fragmented field with specific gaps rather than an emerging one — the next steps depend on whether you are clearing a filing or scouting a gap.
Screen a candidate claim against the F04B core
Given half the corpus sits in positive-displacement pump structure claims, any new material claim should be checked against F04B prior art first, not just against F16K valve filings.
Explore the corpus in EurekaWatch for renewed filing after the lag window
Because publication lags filing by about 18 months, the apparent 2022-2026 decline may partly reverse as later filings publish; revisit the trend after the next data refresh.
Track filing trends in EurekaMap the Shin Jin Ung cluster's claim scope
The strongest co-assignee links in this dataset belong to a small named group rather than a corporation; understanding what they actually claim may reveal a narrow but active pocket of activity.
Review assignee networks in EurekaCommon questions on this landscape
The corpus does not show a single dominant assignee; instead, ownership is fragmented across many filers with a small collaborative cluster around Shin Jin Ung, Lee Kangwook, Lee Geun Hyoung and Kwon Yongchol showing the strongest co-filing links at 11 shared filings each. Larger appliance and compressor names such as Whirlpool and LG Electronics appear in the tracked set but show zero filings in the most recent year. This pattern is more typical of a mature niche than one with an emerging clear leader, so competitive tracking here benefits more from watching co-filing clusters than from ranking single assignees.
Not currently. Filings rose from 2 in 2017 to a peak of 7 in 2019, then fell back to 2 by the 2022 midpoint, which is a flat-to-declining trajectory rather than a growth curve. Because publication lags filing by roughly 18 months, the last one to two years in the dataset are undercounted and should be read as a floor. Even allowing for that lag, the absence of a renewed upward trend through the peak year suggests the core material and geometry combinations have already been substantially claimed.
F04B, positive-displacement pumps, accounts for 114 of the 226 records in this corpus — roughly half the field — making it the single most important class to search before filing. F16J (pistons, seals and gaskets) and F04C (rotary-piston pumps) follow at 37 and 36 records respectively, and the lubricant-specific classes C10M and C10N together add 48 records. F16K, valves specifically, holds only 23 records despite valve materials being explicitly part of the search criteria, suggesting valve-specific material claims are comparatively less crowded than pump and piston structure claims.
EP0400334A2, filed by Iwata Air Compressor Mfg. Co., Ltd. in 1990, claims a piston for an oilless reciprocating compressor where the piston body is made fully or on its circumferential surface of a self-lubricating material, with an optional C-shaped ring groove on that surface. Anyone filing a self-lubricating piston or ring design should check claim scope against this filing specifically around the self-lubricating surface treatment and the ring-groove geometry. It does not cover valve materials or cylinder coatings directly, so those adjacent branches are not blocked by this particular filing.
The IPC composition points to valve-specific wear coatings and lubricant-property indexing (C10N) as comparatively thin relative to the dominant F04B pump-structure claims, and rotary-piston self-lubricating seal composites appear underfiled compared with reciprocating-piston equivalents. Ceramic-lined cylinder liners and oil-free piston ring geometries also show less density than the core piston and pump classes. These are directional signals from filing counts, not a guarantee of freedom to operate, so any specific claim should still be checked against the full prior art in that subclass before filing.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
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Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.