US4786604A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Lead detector kit
Assignee: Individual
•
Filing: 1987-06-22
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Granted: 1988-11-22
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Expires: 2007-06-22
Abstract
Abstract A method and apparatus for detecting the existence of lead in tapwater. The apparatus comprises a kit having one vial filled with a reference solution exhibiting the appearance of clear, partially diluted sodium chromate. A second vial is partially filled with a saturated sodium or potassium chromate solution. Testing is accomplished by filling the second vial with the tap water, permitting any lead within the tap water to react with the sodium or potassium chromate and then visually comparing the resulting clarity of the test solution and the reference solution.
Inventors
- 👤 Robert C. Michael
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:31
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/18; G01N33/1813
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
82 words
A kit for testing for lead concentrations in water in excess of approximately five parts per million comprising: a packaging means including; (a) a first vial constructed from a substantially transparent material and containing a non-chromate reference solution having the appearance of a clear sodium chromate solution, that is an optically clear yellow tinted liquid; and (b) a second vial constructed from a substantially transparent material, said second vial being partially filled with a test solution comprising a saturated sodium chromate solution.
Claim 2
Dependent Claim
82 words
A kit for testing for lead concentrations in water in excess of approximately five parts per million comprising: a packaging means including; (a) a first vial constructed from a substantially transparent material and containing a non-chromate reference solution having the appearance of a clear sodium chromate solution, that is an optically clear yellow tinted liquid; and (b) a second vial constructed from a substantially transparent material, said second vial being partially filled with a test solution comprising a saturated sodium chromate solution.
Claim 3
Dependent Claim
22 words
A kit as defined in claim 1 in which said reference solution comprises a mixture of yellow dye and a liquid medium.
Claim 4
Dependent Claim
36 words
A kit as defined in claim 1 further including packaging means comprising: (c) a generally planar backing member; (d) a substantially transparent envelope affixed to said planar backing member for enclosing said first and second vials.
Claim 5
Dependent Claim
31 words
A testing kit as defined in claim 3 in which said vial enclosing means comprises a substantially transparent thin plastic sheet material affixed proximate the margins thereof to said backing member.
Claim 6
Dependent Claim
131 words
A drinking water testing kit for determining lead concentrations in excess of approximately five parts per million in domestic water supplies, comprising: (a) a display and transport package including: (i) a substantially planar backing member; and (ii) a vial enclosing means affixed to said backing member; (b) a first vial constructed from a substantially transparent material, said vial being disposed within said vial enclosing means and containing therewithin a non-chromate reference solution comprising a mixture of yellow coloring and water said solution being free of precipitate and having the appearance of a clear sodium chromate solution; and (c) a second vial constructed from a substantially transparent material, said second vial being disposed within said vial containing means and being partially filled with a test solution comprising a saturated sodium chromate solution.
Claim 7
Dependent Claim
131 words
A drinking water testing kit for determining lead concentrations in excess of approximately five parts per million in domestic water supplies, comprising: (a) a display and transport package including: (i) a substantially planar backing member; and (ii) a vial enclosing means affixed to said backing member; (b) a first vial constructed from a substantially transparent material, said vial being disposed within said vial enclosing means and containing therewithin a non-chromate reference solution comprising a mixture of yellow coloring and water said solution being free of precipitate and having the appearance of a clear sodium chromate solution; and (c) a second vial constructed from a substantially transparent material, said second vial being disposed within said vial containing means and being partially filled with a test solution comprising a saturated sodium chromate solution.
Claim 8
Independent Claim
186 words
A method for testing for lead concentrations in water in excess of approximately five parts per million, comprising the steps of: (a) mixing within a first, substantially transparent vial a yellow dye and a liquid medium to form a non-chromate reference solution having the appearance of a clear sodium chromate solution, that is an optically clear yellow tinted liquid free of precipitate; (b) mixing within a second substantially transparent vial a saturated sodium chromate solution; (c) adding the water to be tested to said second vial containing said saturated sodium chromate solution; (d) thoroughly mixing the water to be tested with said saturated sodium chromate solution; (e) placing said second vial in an upright, at rest position for a period of time sufficient to permit any lead contained in the water sample to react with the sodium chromate; and (f) comparing the mixture thus formed in said second vial with said reference solution to detect an appearance of greater relative cloudiness in said second vial, thereby indicating the presence of lead in said second vial in an amount in excess of approximately five parts per million.
Claim 9
Independent Claim
186 words
A method for testing for lead concentrations in water in excess of approximately five parts per million, comprising the steps of: (a) mixing within a first, substantially transparent vial a yellow dye and a liquid medium to form a non-chromate reference solution having the appearance of a clear sodium chromate solution, that is an optically clear yellow tinted liquid free of precipitate; (b) mixing within a second substantially transparent vial a saturated sodium chromate solution; (c) adding the water to be tested to said second vial containing said saturated sodium chromate solution; (d) thoroughly mixing the water to be tested with said saturated sodium chromate solution; (e) placing said second vial in an upright, at rest position for a period of time sufficient to permit any lead contained in the water sample to react with the sodium chromate; and (f) comparing the mixture thus formed in said second vial with said reference solution to detect an appearance of greater relative cloudiness in said second vial, thereby indicating the presence of lead in said second vial in an amount in excess of approximately five parts per million.
Claim 10
Dependent Claim
66 words
A method as defined in claim 6 in which said first and second vials each have a volume of approximately four milliliters; in which said first vial is substantially filled with said reference solution; in which said second vial is filled with approximately 2 milliliters of a saturated sodium chromate solution in distilled water prior to adding the water to be tested to said second vial.
Claim 11
Dependent Claim
24 words
A method as defined in claim 7 in which said yellow dye comprises yellow food coloring and in which said liquid medium comprises water.
Claim 12
Dependent Claim
79 words
A kit for testing for lead concentrations in water in excess of approximately five parts per million comprising: a packaging means including; (a) a first vial constructed from a substantially transparent material and containing a non-chromate reference solution being free of precipitate and having the appearance of a clear potassium chromate solution; and (b) a second vial constructed from a substantially transparent material, said second vial being partially filled with a test solution comprising a saturated potassium chromate solution.
Claim 13
Dependent Claim
79 words
A kit for testing for lead concentrations in water in excess of approximately five parts per million comprising: a packaging means including; (a) a first vial constructed from a substantially transparent material and containing a non-chromate reference solution being free of precipitate and having the appearance of a clear potassium chromate solution; and (b) a second vial constructed from a substantially transparent material, said second vial being partially filled with a test solution comprising a saturated potassium chromate solution.
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) | 1991-11-22 | 1992-05-23 | 1992-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-22 | 1996-05-23 | 1996-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-22 | 2000-05-23 | 2000-11-22 | $7700.00 | Window Closed / Lapsed |