Mechanical Seal Testing Patents: Who Leads, Filing Trends 2026
- Filing has cooled since a 2019 peak of 10 records, with the 2022 midpoint at 5 and no rebound visible through the most recent full year.
- China accounts for 61 of 104 receiving-office filings, more than Japan, the US, EPO, UK and Canada combined — testing rig and leakage-test claims are concentrating there.
- The G01M and F16J subclasses dominate at 64 and 46 records respectively, while adjacent branches like G01L pressure measurement and F04D pump-seal integration sit in single digits.
Filing growth compares 2021 (5 records) with 2024 (10) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 104 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Mechanical seal testing and inspection sits at the intersection of rotary and face-seal hardware and the rigs, sensors and endurance benches used to qualify it. The 104-family dataset behind this page combines IPC codes for testing machinery (G01M), pressure and force measurement (G01L), and seal or gasket structure (F16J) with claim text mentioning leakage, pressure or endurance test benches. That combination captures patents on the test method or apparatus itself, not on seal geometry alone.
Coverage runs from 2015 through the most recent data cut-off. Because publication typically lags filing by around eighteen months, the last one to two years in any trend chart will understate actual filing activity.
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Filing trend and IPC composition
Two views of the same 104-family dataset: annual filing volume, and where those filings sit across the IPC classification tree.
A peak in 2019, then plateau
Filings rose from 3 in 2017 to a peak of 10 in 2019, then settled near the 2022 midpoint of 5 with no clear recovery through the latest full year — a flat-to-declining pattern rather than a growth curve.
Testing apparatus outweighs seal structure
G01M (testing machine & structure balance) leads at 64 records and F16J (seals & gaskets) follows at 46, confirming this corpus is centred on test apparatus claims. Material-science branches — B22F powder metallurgy, C22C alloys, C04B ceramics — appear only in single digits, each pointing to seal-material characterisation rather than rig design.
Shares are the percentage of the 104 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Mechanical Seal Testing and Inspection with Eureka
This page is one run against one query. Ask Eureka your own question about mechanical seal testing and inspection and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a representative filing
US20170198815A1 — Mechanical seal and floating ring
Filed by Eagle Industry, this application describes a mechanical seal built from a rotating ring, a stationary ring, and a floating ring positioned axially between them, with the floating ring's sliding portion contacting the rotating ring to seal the annular gap around a rotating shaft.Abstract text is machine-extracted from the original filing and lightly trimmed for length.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | CN103267613A | 一种机械密封性能试验装置 | 57 |
| 2 | US4416458A | Mechanical face seal with minute pores in sliding surface | 44 |
| 3 | US6450502B1 | Rotary seal with relief angle for controlled tipping | 30 |
| 4 | US4997192A | Mechanical seal using pore-dispersed material, and pore-dispersed cemented carbide and method for manufacturi… | 29 |
| 5 | US4423879A | Mechanical seal | 26 |
| 6 | US4407513A | Mechanical seal | 24 |
| 7 | US20020084593A1 | Rotary seal with relief angle for controlled tipping | 23 |
| 8 | CN104712867A | 一种用于钢管水压试验的压力自适应端面密封装置 | 22 |
| 9 | CN201464132U | 机械密封动、静压实验装置 | 22 |
| 10 | JP1992050744A | Method and device for leak inspection of mechanical seal | 21 |
Citation counts are drawn from within this searched corpus and favour older filings that have had more years to accumulate references — read them as a signal of influence, not current relevance.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers say about this field
Three patterns stand out once the filing trend, geography and citation data are read together.
Growth has flattened, not accelerated
The corpus peaked at 10 filings in 2019 and had fallen back to the 2022 midpoint of 5 by the following data point, with the most recent year still partial. That is a plateau, not a technology in early growth.
China is the primary filing venue
China's receiving office accounts for 61 of the 104 tracked families, roughly four times the next-largest venue. Japan and the United States each sit at 16, with Europe, the UK and Canada trailing in single digits.
Apparatus claims outnumber structure claims
Testing-machine classification (G01M) leads seal-structure classification (F16J), indicating the denser claim space is around rigs, benches and measurement methods rather than seal geometry itself.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to mechanical seal testing and inspection, with the prior art for and against each one.
Assignee landscape and collaboration patterns
Filing activity is spread across a mix of seal specialists and materials suppliers, with a small number of recurring co-filing relationships.
Collaboration is limited but structural
Only five co-assignee pairs appear in the dataset. The strongest, between Daido Metal (Taihō Kogyo) and Toyota Industries at 5 joint records, points to an established supplier-integrator relationship rather than a one-off project.
No leading assignee filed in the latest tracked year
Every assignee named in the recent-momentum ranking, including Eagle Industry and Toyota Industries, shows zero filings in the latest year — consistent with the broader plateau, and a reminder that the newest year is always undercounted due to publication lag.
Older US and China filings anchor the citation graph
The most-cited record in the corpus is a China filing on mechanical seal test apparatus at 57 citations, followed by decades-old US filings on face-seal and pore-dispersed seal materials still drawing references today.
| Assignee | Recent year | YoY |
|---|---|---|
| Eagle Industry Co., Ltd. | 0 | — |
| Taiho Kogyo Co., Ltd. | 0 | — |
| Trelleborg Sealing Solutions US, Inc. | 0 | — |
| Toyota Industries Corporation | 0 | — |
| Nihon Tungsten Co., Ltd. | 0 | — |
| Raytheon Technologies Corporation | 0 | — |
| Tanken Seiko Co., Ltd. | 0 | — |
| Nippon EagleBurgmann Co., Ltd. | 0 | — |
Where to take this analysis
This page surfaces the pattern; the next step is testing a specific claim or filing strategy against the full document set.
Check freedom-to-operate on a rig design
Run a targeted search against the G01M and F16J clusters before committing to a specific test-bench architecture, since apparatus claims are the densest part of this corpus.
Explore in EurekaTrack the co-filing relationships
The Daido Metal / Toyota Industries and Eagle Industry / NOK relationships suggest supplier-integrator filing pairs worth monitoring for new joint applications.
Explore in EurekaWatch the under-claimed branches
Pump-integrated test rigs and powder-metallurgy seal materials show low filing density relative to the core clusters, which may indicate open claim space rather than settled art.
Explore in EurekaFrequently asked questions
This field is classified primarily under G01M (testing machinery and structure balance) combined with F16J (seals and gaskets), with claims typically covering the test rig, sensor arrangement, or endurance-cycle method rather than the seal itself. The dataset behind this page uses that combination alongside claim-text matches for leakage test, pressure test and endurance test bench to isolate 104 patent families. Most of these originate from China's receiving office, followed by Japan and the United States.
Filing is spread across established seal manufacturers including Eagle Industry, Toyota Industries and its Daido Metal (Taihō Kogyo) supplier relationship, alongside materials specialists like Sanken Refractory (Nihon Tungsten) and research institutions. No single assignee dominates the corpus, and notably every leading assignee shows zero filings in the most recent tracked year, which is consistent with a broader plateau in activity as well as normal publication lag.
The trend is flat to declining rather than growing. Filings rose from 3 in 2017 to a peak of 10 in 2019, then fell back toward the 2022 midpoint of 5, with the most recent year still partial in the data. That pattern suggests the core testing methods are largely settled, though publication lag of roughly eighteen months means the last one to two years understate true activity.
Relative to the dense G01M and F16J clusters, branches like G01L pressure measurement, F04D pump-seal integration, B22F powder-metallurgy seal materials, and C04B ceramic wear testing each show only single-digit record counts. That does not guarantee those areas are unclaimed, but the low density relative to the core clusters is worth checking with a focused freedom-to-operate search before committing engineering resources to a rig design in those areas.
China's receiving office accounts for 61 of the 104 tracked families, well ahead of Japan and the United States at 16 each. This concentration likely reflects both the volume of domestic manufacturing and testing-equipment production in China and the practice of filing test-apparatus patents domestically before deciding on international extension. It does not necessarily mean the underlying invention activity originated in China for every one of those filings.
Research Mechanical Seal Testing and Inspection in depth with Eureka
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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.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
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.