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Patent landscape, scope, and claims: |
United States Patent 7,284,474: Scope, Claim Set, and US Patent Landscape
United States Patent 7,284,474 claims a piston pumping system with a guide-tube-borne O-ring seal whose nitrogen gas permeation coefficient, radial compression, and groove fill level are tightly specified, plus optional features spanning valve type, piston dimensions, materials, actuation, and micro-delivery outlets. The claim scope centers on a sealing performance envelope designed to suppress gas ingress (nitrogen permeation) in micro-scale piston pumping.
What does claim 1 cover (the core invention)?
Claim 1 (independent) limitations
Claim 1 requires, in combination:
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Pump architecture
- A piston pumping system.
- Piston guided within a guide tube.
- Piston performs a stroke movement along its longitudinal axis.
- The piston opens into a pumping chamber.
- The pumping chamber connects via:
- A liquid-conveying connection with a valve to a storage vessel.
- From the pumping chamber, a liquid conveying connection to a device for delivering the liquid.
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Seal placement and mechanical sealing interface
- Within the guide tube is formed an O-ring seal.
- The O-ring is held by a groove.
- The groove seals off the piston.
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Sealing performance metrics (key differentiators)
- O-ring has a gas permeation coefficient in nitrogen (N2) of:
- 100 to 500 Ncm³mm/(m²hbar).
- The O-ring exhibits radial compression of less than 30%.
- The O-ring fills the groove to a groove filling level of more than 90%.
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Functional relationship
- The pump and delivery are tied to the seal’s achieved performance metrics (the claim requires the system “has” the O-ring with those specific properties while carrying out the piston stroke pumping system).
Independent claim 1 scope in plain terms
Claim 1 is not just “a piston pump with an O-ring.” It is a piston pump + guide tube groove + O-ring combination where the O-ring’s gas-barrier behavior (nitrogen permeation coefficient), compression window, and groove fill fall inside a specified set. This drives claim scope toward micro-dispensing pumps and seals engineered for low gas permeation rather than generic O-ring sealing.
How do dependent claims narrow claim 1?
Claim chart: dependency structure
Below is the narrowing logic across claims 2 to 17.
| Claim |
Additional limitation beyond claim 1 |
Practical narrowing effect |
| 2 |
Groove filling level >95% |
Tightens groove fill from “>90%” to a narrower range |
| 3 |
Valve is a non-return valve |
Limits valve structure/function |
| 4 |
Non-return valve is formed in the connection to delivery device |
Narrows where the check function resides |
| 5 |
Piston diameter 0.25 to 4 mm |
Constrains size class, relevant to micro-pumping |
| 6 |
Piston length 5 mm to 10 cm |
Further constrains geometry envelope |
| 7 |
Stroke length along longitudinal axis 1 mm to 5 cm |
Constrains stroke travel |
| 8 |
O-ring seal consists of silicon |
Material limitation |
| 9 |
Hollow piston where the liquid-conveying connection with valve is integrated |
Moves to an internalized/hollow piston architecture |
| 10 |
Piston movement mechanically controlled |
Forces mechanical actuation rather than electrical |
| 11 |
Mechanical control uses a helical spring |
Tightens actuation mechanism |
| 12 |
Piston movement electronically controlled |
Electrical actuation path |
| 13 |
Piston controlled by a microchip |
Narrows electronic control hardware |
| 14 |
Piston moved by a piezoelectric element |
Tightens actuation mechanism further |
| 15 |
Pump volume from 1 microliter to 1 ml |
Constrains capacity class |
| 16 |
Delivery device includes nozzle, micro-pin and/or microcutter, canula and/or outlet |
Narrows delivery element types (not necessarily one device) |
| 17 |
O-ring cord thickness 0.3 to 3 mm |
Constrains seal geometry |
Scope boundaries: what is covered vs. excluded
Included design space
A system fits the claims when it satisfies claim 1’s seal performance metrics and architecture, then any dependent features are optionally satisfied (depending on infringement theory by each claim).
Key included zones:
- Seal performance-defined O-ring sealing in a piston-guide-tube groove interface.
- Nitrogen permeation coefficient between 100 and 500 Ncm³mm/(m²hbar).
- Radial compression <30%.
- Groove fill >90% (and optionally >95%).
- Micro-scale to small-scale piston pumping as indicated by dependent geometry and volume limits (diameter 0.25-4 mm, stroke 1 mm to 5 cm, volume 1 µL to 1 mL).
Likely excluded design space
- If an accused system uses a different gas permeation coefficient outside 100-500 for nitrogen, it does not meet claim 1 as written.
- If the O-ring is not held in a groove within the guide tube that seals off the piston, it does not meet claim 1.
- If sealing relies on different sealing elements that do not meet the defined O-ring groove fill and compression parameters, claim 1 likely fails.
- If the piston pumping system does not have the defined connection chain (storage vessel via valve; delivery device downstream), claim 1 fails.
Claim interpretation pressure points (where scope is most litigated-prone)
Even without external prosecution history, the claim text creates predictable interpretation issues:
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Permeation coefficient
- The claim ties to nitrogen (N2) and a specific unit expression. Any dispute turns on:
- How permeation coefficient is measured,
- Whether reported values correspond to the same test method and conditions,
- Whether an accused product’s value is within 100 to 500.
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Radial compression definition
- Claim requires less than 30% radial compression.
- Disputes can center on:
- How compression is calculated (installation compression vs. operating compression),
- Whether compression is measured at rest, during stroke, and/or after thermal conditioning.
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Groove filling level
- Claim requires >90% (or >95% in claim 2).
- This parameter is sensitive to manufacturing tolerances and how “fill level” is determined from groove geometry and O-ring cross-section.
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Actuation categories
- Dependent claims split into mechanical control (claim 10-11) vs electronic control (claim 12-14). A system that uses hybrid control could be contested against “mechanically controlled” or “electronically controlled” characterization unless claim language is satisfied as a matter of fact.
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Hollow piston integration
- Claim 9 is a significant structural narrowing: it requires integration of the liquid conveying connection with the valve into the hollow piston.
US patent landscape: likely crowded adjacent space vs. narrow niche
Why this patent is positioned narrowly
Most piston micro-dispensing patents focus on:
- actuator type (piezo, spring-microactuator),
- valve/check behavior,
- microfluidic delivery tips,
- stroke/capacity targeting.
This patent adds a distinctive, quantitative seal barrier requirement:
- nitrogen permeation coefficient window,
- radial compression cap,
- groove fill threshold.
That combination is a strong narrowing lens. Competitors can still design around by:
- using alternative seal materials/architectures,
- selecting O-rings with different permeation coefficients,
- changing compression set-up,
- altering groove fill geometry,
- using non-O-ring sealing interfaces.
Adjacency clusters to expect
Based on the functional elements recited in claims 3-4, 5-7, 9, 10-14, and 16, the patent sits at the intersection of:
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Micro piston pumping and microdispensing
- geometry and stroke constraints,
- pump volume ranges (1 µL to 1 mL).
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Check valve / non-return valve integration
- in-line check behavior for one-way flow and prevention of backflow.
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Actuation tech
- mechanical control with helical spring (claim 11),
- electronic control with microchip (claim 13),
- piezoelectric actuation (claim 14).
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Low-gas permeation sealing
- O-ring material engineering (claim 8 silicon),
- quantitative gas-barrier and compression/fill tuning.
Landscape risk signal
The patent’s risk is strongest where an accused system:
- uses an O-ring in a groove-based guide tube seal,
- operates as a piston pump with a check valve and storage/delivery connections,
- employs sealing with low nitrogen permeation engineered into the specified range,
- maintains radial compression and groove fill consistent with the claim.
In practice, this means the highest risk designs are those that replicate the seal engineering strategy, not just the pump concept.
Business relevance: infringement mapping strategy
Primary claim attack/defense lever: seal property window
If evaluating freedom-to-operate:
- The first gate is whether the accused system’s O-ring seal meets the nitrogen permeation coefficient window.
- Next gates are radial compression and groove fill.
This creates a “technical evidence” approach rather than a purely architectural approach.
Secondary gate: structural arrangement
If seal metrics are met, then architecture must match:
- piston guided in guide tube,
- groove-held O-ring within guide tube sealing the piston,
- pumping chamber connected to storage vessel via valve,
- delivery connection from pumping chamber to delivery device.
Dependent claim relevance
Dependent claims (5-7, 8, 9, 10-11, 12-14, 15-16, 17) can increase certainty when an accused system matches:
- piston dimensions and stroke range,
- silicon seal composition,
- hollow piston with integrated valve connection,
- spring or piezo actuation,
- delivery tip types.
Key Takeaways
- Claim 1 is defined by seal performance metrics: nitrogen permeation coefficient 100 to 500 Ncm³mm/(m²hbar), radial compression <30%, and groove fill >90%, coupled to a piston pumping architecture using an O-ring in a guide-tube groove.
- Dependent claims narrow architecture and implementation via valve configuration, micro-scale piston geometry, pump volume, silicon O-ring material, hollow piston with integrated valve connection, actuation type (spring vs piezo), and delivery nozzle/tip types.
- The patent’s landscape position is narrower than generic micro piston pumping patents because it hinges on quantitative gas-barrier sealing parameters. Design-around strategies typically target seal properties and/or groove-compression geometry.
FAQs
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Is the seal performance (nitrogen permeation coefficient) mandatory for infringement of claim 1?
Yes. Claim 1 requires an O-ring seal with a nitrogen permeation coefficient in 100 to 500 Ncm³mm/(m²hbar) plus the compression and groove fill thresholds.
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Do dependent claims like “silicon” broaden or narrow protection?
They narrow. Claim 8 limits the O-ring seal composition to silicon, so systems using other materials fall outside claim 8 but may still fall within claim 1 if they meet claim 1’s seal-property limits.
-
Can a design avoid the patent by changing valve placement?
It can. Claims 3 and 4 specify “non-return valve” and where it is formed (in the connection to the delivery device for claim 4). Claim 1 still requires a valve in the liquid-conveying connection to the storage vessel, so the design must still satisfy claim 1 architecture.
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How do piston dimensions affect claim coverage?
Claims 5-7 impose dimensional limits (diameter, length, stroke). If an accused device exceeds or falls below these ranges, it may avoid those dependent claims, but claim 1 can still apply if the seal and core architecture match.
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What is the most effective technical evidence path for claim mapping?
Focus first on the O-ring’s nitrogen permeation, then radial compression and groove fill level, because those are explicit numeric requirements in claim 1.
Cited Sources
None.
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