US4452899A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for metering biological fluids
Assignee: Clinical Diagnostic Systems Inc
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Filing: 1982-06-10
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Granted: 1984-06-05
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Expires: 2002-06-10
Abstract
Abstract A method is disclosed for repeatedly and accurately depositing predetermined amounts of fluid, especially biological fluids, onto generally planar analysis slides. Fluid is aspirated into a disposable metering tip which is rapidly moved into a metering position where the fluid is expelled onto a slide. During movement of the tip into the metering position, a partial vacuum is created on the fluid in the tip, causing the fluid to be drawn up into the tip and thereby preventing fluid from being prematurely expelled onto the slide.
Inventors
- 👤 Wilton D. Alston
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 03:43
CPC Classifications
G; G01; G01N; G01N35/00; G01N35/10; G01N35/1081; G01N35/1083; G01N35/00029; G01N35/1009; G01N35/1016; G01N2035/102; G01N2035/1027; G01N2035/1034; Y; Y10; Y10T; Y10T436/00; Y10T436/11; Y10T436/112499; Y10T436/119163; Y10T436/25; Y10T436/2575
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
175 words
A process for the precise dispensing of a biological fluid from a metering tip onto a generally planar analysis slide, said process comprising the steps of: introducing a quantity of fluid into said tip, said tip having an air space above the fluid; moving the tip toward a metering position in which the tip is spaced between about 0.030 cm and about 0.15 cm from an analysis slide; creating a partial vacuum on the fluid in the tip when the tip is at a point spaced from the metering position in an amount effective to prevent pre-spotting when the tip is moved into the metering position; moving the tip into the metering position at a velocity that would cause pre-spotting in the absence of the partial vacuum; pressurizing the air and fluid in the tip for a preselected period to force a selected volume of fluid onto the slide at a predetermined dispense rate; and maintaining said tip briefly in the metering position after said period and then withdrawing the tip from said metering position.
Claim 2
Dependent Claim
175 words
A process for the precise dispensing of a biological fluid from a metering tip onto a generally planar analysis slide, said process comprising the steps of: introducing a quantity of fluid into said tip, said tip having an air space above the fluid; moving the tip toward a metering position in which the tip is spaced between about 0.030 cm and about 0.15 cm from an analysis slide; creating a partial vacuum on the fluid in the tip when the tip is at a point spaced from the metering position in an amount effective to prevent pre-spotting when the tip is moved into the metering position; moving the tip into the metering position at a velocity that would cause pre-spotting in the absence of the partial vacuum; pressurizing the air and fluid in the tip for a preselected period to force a selected volume of fluid onto the slide at a predetermined dispense rate; and maintaining said tip briefly in the metering position after said period and then withdrawing the tip from said metering position.
Claim 3
Dependent Claim
27 words
A process, as defined in claim 1, wherein the air space above said fluid is vented to the atmosphere, before creating a partial vacuum on the fluid.
Claim 4
Dependent Claim
19 words
A process, as defined in claim 1, wherein said partial vacuum is equal to about 0.4 inches of water.
Claim 5
Dependent Claim
30 words
A process, as defined in claim 1, wherein said air and fluid are pressurized to about 1.5 inches of water in forcing the 10 μl of fluid onto the slide.
Claim 6
Dependent Claim
15 words
A process, as defined in claim 1, wherein said selected volume is about 10 μl.
Claim 7
Dependent Claim
19 words
A process, as defined in claim 1, wherein said dispense rate is between about 10 μl/sec and 300 μl/sec.
Claim 8
Dependent Claim
24 words
A process, as defined in claim 1, wherein said tip is maintained in said metering position between about 0.05 sec and about 0.5 sec.
Claim 9
Dependent Claim
28 words
A process, as defined in claim 1, wherein said tip is withdrawn from the metering position at the rate of between about 0.5 cm/sec and about 5.08 cm/sec.
Claim 10
Dependent Claim
54 words
A process, as defined in claim 1, wherein a positive displacement pump is used to introduce fluid into the tip and create said vacuum, said pump having a piston which is movable through a first distance in one direction to aspirate said fluid and an additional distance in said direction to create said vacuum.
Claim 11
Dependent Claim
26 words
A process, as defined in claim 1, wherein said point spaced from the metering position is between about 1/4" and about 1/2" from the metering position.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-06-05 | 1987-12-05 | 1988-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-05 | 1991-12-05 | 1992-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-05 | 1995-12-05 | 1996-06-05 | $7700.00 | Window Closed / Lapsed |