Earth Pressure Balance and Slurry Shields Patents: Top Filers & Trends 2026
- Concentrated but not locked up. the top 5 assignees hold 26.9% of all 78 records in scope, and the top 10 hold 46.2% — leaving over half the field to a long tail of single- and few-filing entrants.
- Filing is still accelerating. filings rose from 4 in 2021 to 7 in 2024, a +75% increase, with 2024 standing as the peak year recorded so far.
- Almost everything sits under one IPC subclass. E21D (shafts, tunnels & mine support) covers 89.7% of records, while conveying, mixing and mine-safety classes each cover under 7% — a sign that muck handling and conditioning chemistry are comparatively under-claimed.
Filing growth compares 2021 (4 records) with 2024 (7) — 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 78 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Earth pressure balance (EPB) and slurry shield tunnel boring machines dominate mechanised tunnelling in soft and mixed ground, and the patent activity tracked here follows the working problems specific to that method: face pressure control, conditioning foam chemistry, slurry separation plant, screw conveyor discharge, muck consistency and the ground settlement outcomes that all of the above are meant to control. The scope spans records published between 2015 and the 2026 data cut-off.
The 78 records in scope are dominated by Chinese filers and receiving offices, with Japanese, US, UK, Singaporean and Malaysian activity forming a smaller but present secondary tier. Reading the dataset by patent family, rather than raw document count, is the fairer way to gauge which organisations are genuinely active versus which have filed a cluster of continuations around a single project.
Filing trend and technology composition
Two views of the same 78 records: how filing activity has moved year over year, and how it distributes across IPC subclasses. Because a single record can carry more than one classification, the subclass shares add up to well over 100%.
Filing trend, 2017–2026
Annual filings moved from 5 in 2017 to a recorded peak of 7 in 2024, including a +75% rise between 2021 (4) and 2024 (7). 2025 and 2026 show fewer records, but publication typically lags filing by around 18 months, so the most recent two years understate actual filing activity rather than showing a genuine slowdown.
IPC subclass composition
E21D (shafts, tunnels and mine support) appears in 89.7% of the 78 records, confirming this is fundamentally a tunnelling-machine dataset. Conveying and material handling (B65G), mixing and stirring (B01F), and mine safety and ventilation (E21F) each sit near 5-6%, with spraying/atomising, misc. materials, foundations and digital data processing rounding out the remainder at under 4% each.
Shares are the percentage of the 78 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Earth Pressure Balance and Slurry Shields with Eureka
This page is one run against one query. Ask Eureka your own question about earth pressure balance and slurry shields and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a representative filing
Foam generator for an earth pressure balance shield tunnel boring machine (US20170067339A1)
The application describes a foam generator built around a mixing chamber with separate inlets for a foamable liquid and a gas, feeding a tubular flow chamber with a dedicated gassing section, so that soil conditioning foam can be produced and dosed in a controlled way ahead of excavation.Filed by MC-Bauchemie Muller GmbH & Co. KG, published 2017-03-09.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6347838B1 | Method for replacing cutters of tunnel-excavating machine, method for excavating tunnel, and tunnel excavatin… | 47 |
| 2 | CN106285699A | 基于同步射流的土压平衡盾构泥饼防治系统 | 33 |
| 3 | CN105201520A | 砂卵石地层土压平衡盾构施工渣土改良工艺 | 32 |
| 4 | CN105781561A | 研究软弱地层应力响应的室内土压平衡盾构掘进模拟系统 | 30 |
| 5 | CN105127707A | 隧道内拆解土压平衡盾构机的方法 | 30 |
| 6 | CN104131817A | 一种富水砂卵石地层盾构掘进施工渣土改良工艺 | 24 |
| 7 | CN107416994A | 一种泥水盾构机在细颗粒地层中施工的泥浆多级分离方法 | 23 |
| 8 | CN201367906Y | 螺旋输送机 | 19 |
| 9 | CN110500108A | 一种新型土压平衡盾构机及工作方法 | 18 |
| 10 | GB2263490A | Mechanical shield driving method using foaming agent | 18 |
Citation counts reflect a searched corpus and favour older records; treat them as a signal of influence rather than of current technical importance.
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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Three read-outs from the underlying data that matter more for strategy than the raw counts alone.
Leadership is real but not exclusionary
The top 5 assignees combine for 26.9% of all 78 records and the top 10 for 46.2%. That leaves more than half the field held by organisations with only a handful of filings each, which is a workable environment for a new entrant rather than a closed one.
Activity is still building, not cooling
Filings grew from 4 in 2021 to 7 in 2024, the peak year recorded. The apparent dip in 2025-2026 reflects publication lag of roughly 18 months rather than declining interest, so 2024 is the last year that should be read as a complete signal.
Claim space is dense at the core, thinner at the edges
Almost nine in ten records sit in E21D, the shafts-and-tunnels class. Conveying, mixing, mine safety and foundations classes each cover under 7% of records, which points to comparatively open claim space around material handling and conditioning chemistry rather than the core machine architecture.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to earth pressure balance and slurry shields, with the prior art for and against each one.
Who is filing, and where the gaps sit
Filing activity clusters around Chinese state infrastructure groups and a smaller number of specialist chemical and machine builders, with universities contributing a steady secondary stream.
A single leader, then a shallow drop-off
The leading assignee holds 6 records; by the tenth position the count has fallen to 3, the same level as fifth place. The curve flattens quickly rather than tailing off gradually, which is typical of a field still being staked out.
Chemistry suppliers partner with contractors
The strongest co-assignee pairing links a construction group with a specialty chemicals supplier around conditioning products, alongside several pairings between related engineering bureaus, suggesting joint filing is more common between complementary specialisms than between direct competitors.
Filing is heavily domestic-first
China accounts for 59 of the 78 records by receiving office, with Japan and the United States at 5 each and the UK, Singapore and Malaysia forming a smaller international tier. Any freedom-to-operate check needs to weight Chinese filings accordingly rather than treating this as a globally even dataset.
| Assignee | Recent year | YoY |
|---|---|---|
| China Railway Engineering Equipment Group Co., Ltd. | 0 | — |
| China Railway 12th Bureau Group Co., Ltd. | 0 | -100% |
| China Railway Construction Heavy Industry Co., Ltd. | 0 | — |
| Central South University | 0 | — |
| Taiyo Kensetsu Co., Ltd. | 0 | — |
| China Railway 11th Bureau Group Urban Rail Transit Engineering Co., Ltd. | 0 | — |
| Shanghai Jiao Tong University | 0 | — |
| PORR BAU | 0 | — |
Where to take this analysis
The landscape points to a few concrete next steps depending on what a team needs to decide.
Check freedom-to-operate against the most-cited records
The most-cited documents in this set, including US6347838B1 and several Chinese records on foam-based conditioning and ground response, are the ones most likely to have spawned dependent or continuation filings worth checking individually.
Explore citing records in EurekaMap the co-filing network before approaching partners
The strongest co-assignee pairings show contractors filing jointly with chemical suppliers and with related engineering bureaus, which is a useful map of who already collaborates before proposing a new partnership.
Trace assignee relationships in EurekaDraft around the under-claimed branches
Muck consistency sensing, screw conveyor torque control and slurry separation automation all carry fewer records than the core E21D machine architecture, which is where a narrowly drafted first claim has the best chance of standing clear of prior art.
Search white space in EurekaCommon questions about this landscape
The dataset ranks 69 companies and research institutes across 78 records, with the leading assignee holding 6 records. The top 5 assignees together account for 26.9% of all records and the top 10 for 46.2%, so while there is a clear leader, the field is not dominated by any single filer. Chinese state infrastructure and engineering groups make up most of the top ranks, with Japanese contractors and a German conditioning-chemicals specialist also appearing among the more active filers.
Filings grew from 4 in 2021 to 7 in 2024, a +75% increase, with 2024 the highest year recorded in the dataset. The lower counts shown for 2025 and 2026 are not evidence of a slowdown; publication typically lags actual filing by around 18 months, so recent years are still being backfilled. Based on the 2021-2024 trend, filing activity has been building rather than cooling.
E21D, the shafts-and-tunnels IPC subclass, appears in 89.7% of the 78 records, confirming that most activity centres on the tunnel boring machine and shield structure itself. Conveying and material handling, mixing and stirring, and mine safety and ventilation each appear in only 5-6% of records, and spraying, foundations and digital data processing classes sit even lower. That imbalance suggests conditioning chemistry, muck handling and digital monitoring are comparatively open relative to core machine claims.
US6347838B1, covering cutter replacement and excavation methods for a tunnel-excavating machine, is the most-cited record in this landscape with 47 citations. High citation counts inside a searched corpus tend to favour older, foundational filings rather than currently central technology, so this signals historical influence on later cutter-replacement and excavation method claims rather than an indication that the patent covers today's leading-edge approach.
The clearest gaps sit outside the dominant E21D machine-architecture class, in areas like slurry separation plant automation, muck consistency sensing, screw conveyor torque control and conditioning foam dosing chemistry, each represented by only a handful of records. A first claim drafted narrowly around sensing or automation logic in one of these branches, rather than around the shield structure itself, has more room to clear existing prior art.
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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.