Patent: 5,629,209

Summary for Patent: 5,629,209

Title:	Method and apparatus for detecting viscosity changes in fluids
Abstract:	An apparatus for detecting changes in the viscosity of a fluid comprises a cartridge having a fluid receiving/dispensing reservoir, one or more fluid-receiving chambers, and a conduit that permits fluid communication between the fluid receiving/dispensing reservoir and the fluid-receiving chamber. Fluid is introduced into the cartridge through an injection port and fills the reservoir, moving from the reservoir through the conduit into the chamber. An air vent/fluid plug device in fluid communication with the chamber permits air to exit while the fluid enters the system but prevents the fluid from leaving after the chamber is filled. A freely movable ferromagnetic material is placed within the fluid-receiving chamber and is caused to move by an electromagnet. Changes in the viscosity of the fluid are detected by determining the position of the ferromagnetic material in the fluid-receiving chamber.
Inventor(s):	Braun, Sr.; Walter J. (Aurora, CO), Boiarski; Anthony A. (Upper Arlington, OH), Braun, Jr.; Walter J. (Aurora, CO), Braun; Steven P. (Peoria, AZ)
Application Number:	08/545,523
Patent Claims:	see list of patent claims

Executive summary
United States Patent 5,629,209 claims an instrumented, sealed cartridge for measuring viscosity changes using (i) a freely movable ferromagnetic element in one or more fluid-receiving chambers, (ii) actuation by an electromagnet, (iii) position sensing by a radio-frequency (RF) detector, and (iv) cartridge architecture that uses air vent/fluid plug devices to vent displaced air during fill while preventing fluid loss. Dependent claims narrow to human blood, 2–6 chambers for comparisons, cartridge viscosity-altering substances, and specific hematology-relevant reagents plus preferred temperature and motion/sensing implementations. The claim set is structurally specific enough to create design-around leverage on cartridge venting, actuation and sensing modalities, and the “freely movable ferromagnetic” sensing element, but the core combination is broad in functional language and is likely to overlap with earlier viscosimetry approaches that use oscillating magnetic elements and contactless RF position detection, and with later point-of-care blood viscosity/aggregation or coagulation-related viscosity measurements that use disposable cartridges and internal reagent chemistry.

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US Patent 5,629,209 claims: what apparatus features are required to practice the invention?

Independent claim 1 requires all of the following in combination:

1. Cartridge architecture

   • A fluid receiving/dispensing reservoir connected via a plurality of conduits to one or more fluid-receiving chambers.
   • A cartridge injection port for introducing the fluid to the reservoir.

2. Air vent/fluid plug devices

   • One or more air vent/fluid plug devices, each in fluid communication with each fluid-receiving chamber.
   • During introduction: permits venting of air displaced from the reservoir/conduit/chamber.
   • During operation: prevents fluid from leaving via the vent/fluid plug device.

3. Movable ferromagnetic element

   • A ferromagnetic material free to move within each fluid-receiving chamber.

4. Actuation and detection

   • “Means for moving” the ferromagnetic material in the chamber.
   • “Means for detecting a position” of the ferromagnetic material in the chamber.

Functional effect: viscosity changes in the fluid are inferred from position behavior of the movable magnetic element after induced motion and allowed settling. The claims do not require a particular oscillation waveform, equilibrium time constant, or calibration method, so long as the device detects “position” consistent with viscosity-dependent motion.

What does claim scope capture versus exclude?

• Captured: any implementation where a magnetic/ferromagnetic element moves in fluid and its position is detected by an RF detector, coupled with a cartridge having venting that vents air but prevents fluid leakage.
• Excluded by structure: if the device lacks the vent/fluid plug feature, lacks the cartridge reservoir-conduit-chamber architecture, or uses a non-ferromagnetic sensing element (or a fixed element that does not move in the fluid).
• Gray area: “means for detecting” is broad enough that embodiments could use other position detection technologies, unless later narrowed by dependent claims (claims 9, 17, 22, 29 in the provided set explicitly require RF detection for those dependents).

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Which dependent claims narrow the device to blood viscosity testing and multi-chamber comparisons?

Blood-specific claims

Claims 10–11 narrow “fluid” to human blood and recite the cartridge specifics:

• Claim 11 requires:
  • cartridge with two to six blood-receiving chambers
  • plurality of conduits allowing fluid communication
  • injection port
  • air vent/fluid plug devices in communication with each chamber that vent air but prevent blood loss
  • freely movable ferromagnetic material in each chamber
  • motion means and position detecting means

Chamber count and parallel testing

• Claim 11: two to six chambers supports built-in comparative runs (claim 3 in the generic apparatus; claim 11 tightens it to blood use with 2–6 chambers).
• Claim 3 (apparatus) adds: at least two fluid-receiving chambers for comparing viscosity changes.

Simultaneous dispensing

• Claim 5 (apparatus) and claim 13/18 (blood-specific apparatus) require the reservoir to dispense simultaneously to more than one chamber, strengthening the argument that the test is a controlled parallel exposure rather than separate, sequential assays.

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What patents protect viscosity measurement using magnetic elements and position sensing, and how does 5,629,209 map to that landscape?

A complete competitive “patentability and infringement” map requires identifying (a) the priority date of 5,629,209, (b) the file history and cited references, and (c) the relevant claims of earlier and later patents. Those record-level facts are not provided here. Under the constraint, only a claim-structure-based analysis can be completed.

Claim-structure adjacency (high-likelihood overlap categories)

5,629,209 is likely to overlap with pre-existing and later patent families in these clusters:

1. Magnetic viscosimetry / magnetically actuated microelements

   • Approaches that move a magnetic element through a fluid and correlate motion to viscosity (often via settling time, oscillation damping, or position after a controlled pulse).

2. Contactless position detection via RF or electromagnetic sensing

   • Non-contact detection systems for magnetic elements using RF inductive coupling, resonant circuits, or radio-frequency tracking.

3. Disposable cartridges for point-of-care fluid handling

   • Reservoir, conduit networks, and venting/leak-prevention structures for controlled fill of chambers.

4. Reagent integration for blood chemistry inside sealed cartridges

   • Cartridge-contained viscosity modifiers (the dependent claims list multiple coagulation, platelet, and surface-active chemistry reagents).

Most critical claim elements for overlap

• The movable ferromagnetic element plus position detection is the “core physics” combination.
• The RF detector in dependents (claims 9, 17, 22, 29) is the key electronics constraint that can narrow overlap versus magnetic actuation with optical or Hall sensors.
• The air vent/fluid plug is a distinct mechanical/cartridge constraint that can reduce overlap against designs that rely on capillaries, stop valves, or complete priming rather than vent-and-plug architecture.

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How strong is the patent estate for US 5,629,209 based on claim breadth and enforceability pressure points?

Where enforceability is strongest

• Integrated combination claim: claim 1 binds together cartridge fluid-handling, vent/fluid plug, movable ferromagnetic element, actuation, and position detection. This reduces the set of independently reusable sub-features.
• Blood-specific tightening: claims 11 and 18 narrow to human blood, chamber count, and cartridge fill behavior that prevents blood loss through vents.

Where enforceability is weakest (design-around and validity risk vectors)

Because claim 1 uses “means” language for moving and detecting, enforceability will tend to hinge on the statutory interpretation of those means plus the specific limitations that dependent claims add. Practical risk vectors:

1. Replace RF position detection (dependent claims 9/17/22/29)

   • If a competitor uses another contactless sensor (optical, Hall array, magnetoresistive, ultrasound echo, capacitive tracking) they may avoid the RF-specific dependents. Whether they can still read claim 1 depends on whether “means for detecting a position” is interpreted broadly (it is broad) and whether the sensing element is still detected by “radio frequency” or something else.

2. Fix the ferromagnetic element (or confine it in a way that removes “free to move”)

   • If the ferromagnetic element is constrained to a fixed track or fixed depth so it does not freely translate in the viscosity-dependent way, the “free to move” requirement can be challenged.

3. Eliminate the air vent/fluid plug architecture

   • Many cartridge systems use porous membranes, capillary priming, or one-way valves rather than “air vent/fluid plug devices.” Even if viscosity measurement physics remains, avoiding that specific fill/leak-prevention feature can reduce infringement exposure.

4. Move from cartridge-contained viscosity-modifying chemistry to external mixing

   • Dependent claim 2, 12, 27, 20, 19, 21 require viscosity-altering substances placed within the cartridge, with lists of specific reagents. Competitors using pre-treated blood, external reagent cassettes, or post-cartridge mixing may avoid dependents.

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Which formulations are protected by 5,629,209 for blood viscosity alteration inside the cartridge?

The patent’s “formulation” protection here is not about dosage forms of a drug; it is about viscosity-modifying substances placed in the cartridge that interact with blood to alter viscosity-related behavior of the movable ferromagnetic element.

Viscosity-altering substances (dependent claims 20 and 19)

• Claim 20 lists: protamine, platelet-activating factor, factor VIII, factor IX complex, factor XVII, fibrinogen, aminocaproic acid, thrombin, thromboplastin, vitamin K, calcium chloride, kaolin, diatomaceous earth.
• Claim 19 defines anticoagulant selection: heparin, warfarin, dicumarol, acenocoumarol, phenprocoumon, diphenadione, phenindione, sodium citrate, citric acid, citrate dextrose, citrate phosphate dextrose, aspirin, and edetate disodium.

Varying reagent amount by chamber

• Claim 21 permits the amount of viscosity-altering substance in each chamber to vary, supporting dose-response or comparative testing across chambers.

Practical implication

Cartridge designs that keep the viscosity-modifying reagents outside the sealed cartridge (or use different classes of modifiers not listed in the dependent claims) reduce exposure to those dependents. Claim 1 and 11, however, do not require those reagents; dependents do.

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What method steps are required by the claims of 5,629,209, and where are the closest procedural design-arounds?

Method claim 24 requires

1. Heating the cartridge to an “optimal temperature.”
2. Introducing fluid (blood if using dependent claim 31).
3. Venting displaced air through the air vent/fluid plug device while preventing fluid from leaving via the same device.
4. Inducing motion in a freely movable ferromagnetic material.
5. Allowing the ferromagnetic material to come to rest for a period.
6. Detecting position of the ferromagnetic material.

Method-dependent narrowing

• Claim 25: repeat motion/rest/detect steps.
• Claim 26: further emphasizes preventing fluid leaving via vent/fluid plug.
• Claim 27: contacting fluid with a viscosity-altering substance within the cartridge.
• Claim 28: motion induced by an electromagnet.
• Claim 29: position detected by a radio frequency detector.
• Claim 30: optimal temperature 98.6°F ± 2°F.
• Claim 31: fluid is human blood.

Procedure design-around

• Use a different temperature control regime and avoid claim 30 (still leaving claim 24 intact).
• Use a non-electromagnetic actuation (avoid claim 28 dependently).
• Use a non-RF position detection (avoid claim 29 dependently).
• Perform air removal differently than via the vent/fluid plug device (avoid claim 24/26’s vent structure).
• Keep viscosity-altering substances external (avoid claim 27/12/2).

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How does 5,629,209 compare with typical point-of-care blood assay patent estates?

Without the cited art and priority date, the most defensible comparison is by claim architecture:

Distinctive elements versus typical blood assay cartridge patents

• Many cartridge patents emphasize: flow control, microfluidics, membranes, and reagent reservoirs.
• 5,629,209’s distinct engineering nucleus is the movable ferromagnetic element and the position detection approach. That is atypical compared with clot detection via optical density, mechanical impedance, or imaging.

Distinctive element versus typical viscosimetry patents

• Many viscosimetry patents use viscometers (capillary, rotational, oscillatory) and sample preparation external to the sensor.
• 5,629,209 ties the viscosity readout to a sealed disposable cartridge with a defined fill/air vent strategy.

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What generic entry risks exist for patents like 5,629,209?

There is no “generic entry” in the small-molecule sense because the claims are directed to an apparatus and method rather than an FDA-approved drug substance. The business risk is technology substitution:

• Competitors can develop non-infringing viscosimeters using different sensing modalities or cartridge fill architectures.
• If the patent is used as a licensing anchor in a point-of-care blood testing platform, risk shifts to design-around and faster-to-market competitors that avoid RF detection, vent/fluid plug features, or the freely movable ferromagnetic element’s motion model.

A complete freedom-to-operate and infringement landscape requires file wrapper data and the full claims set; those are not provided.

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Key takeaways

• Claim 1 is an integrated system claim: cartridge fluid network + injection port + vent/fluid plug fill-leak prevention + freely movable ferromagnetic element + actuator + position detection.
• Blood-focused protection is concentrated in dependent claims requiring human blood, 2–6 chambers, and simultaneous dispensing to multiple chambers.
• Enforceability pressure points are the easy-to-change components: RF detection, actuation modality, the “free to move” constraint, and cartridge air vent/fluid plug architecture.
• “Formulation” protection in this patent is really cartridge chemistry: dependent claims specify anticoagulants and a defined list of viscosity-altering substances located inside the cartridge, including chamber-to-chamber varying amounts.
• The practical licensing and competitive risk is less about FDA generic entry and more about technology redesign in disposable cartridge viscosimetry.

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FAQs

1. Does US 5,629,209 require RF sensing for claim 1 infringement?
   No. RF is required only in the RF-position dependents; claim 1’s “means for detecting” is broader.

2. Can a competitor avoid infringement by using a non-electromagnetic actuator?
   It may avoid the electromagnet dependents, but claim 1 still requires “means for moving” the ferromagnetic material, so the design must still meet the claim’s moving requirement.

3. Are the listed anticoagulants and viscosity-altering substances required for the broad invention?
   No. They appear in dependent claims tied to blood handling and reagent placement.

4. Does the patent cover multi-chamber comparative viscosity testing?
   Yes. Claim 3 requires at least two chambers for comparing changes, and blood dependents specify two to six chambers.

5. Is the vent/fluid plug device an essential feature?
   Yes for claim 1 and method claim 24 as written, because the air vent/fluid plug architecture is explicitly recited for venting displaced air while preventing fluid loss.

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References

No sources were cited because the question provides only the asserted claim text for US 5,629,209 and does not include bibliographic data, prosecution citations, priority information, expiration status, or Orange Book/FDA context.

Details for Patent 5,629,209

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Grifols Biologicals Llc	PROFILNINE, PROFILNINE HP, PROFILNINE HT, PROFILNINE SD	factor ix complex	For Injection	102476	July 20, 1981	5,629,209	2015-10-19