US4004453A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for detecting oil in water
Assignee: Individual
•
Filing: 1975-12-08
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Granted: 1977-01-25
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Expires: 1995-12-08
Abstract
Abstract Simple and economical methods for accurately determining low concentrations of particulate oil in water. In one method a sample of water is first filtered at a controlled rate. A dye-impregnated pad is pressed against the upstream surface of the filter element and then removed. The upstream surface of the filter element may now be observed with the eye against colorations of known concentrations for variations in color intensity clearly discernible within the range of 0 to 30 ppm (parts per million) by volume of oil-in-water. The dye-impregnated pad is prepared by submerging a white absorbent material in a saturated solution of an oil-soluble, water-insoluble dye, and drying them in a rack under vacuum. In another method, where the sample also contains discoloring pigmented contaminants, an intermediate pad is pressed between the filter element and the dye-impregnated pad, and its coloration compared to known standards. In lieu of the intermediate pad method, a thin prefilter is placed on the upstream surface of the filter element during filtering, then discarded, and the filter element is processed as described in the first method above.
Inventors
- 👤 Per T. Thyrum
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:47
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/18; G01N33/1826; G01N33/1833; Y; Y02; Y02A; Y02A20/00; Y02A20/20; Y10; Y10T; Y10T436/00; Y10T436/21
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
77 words
A method for determining the presence of a first liquid of low solubility and low surface activity particulately dispersed in a second liquid, comprising: filtering a sample of said liquids through a porous filter element at a controlled flow rate; pressing a pad impregnated with an oil-soluble, water-insoluble dye against the upstream surface of the element; and removing said pad and observing the color stain on the surface of said element which was contiguous with said pad.
Claim 2
Independent Claim
77 words
A method for determining the presence of a first liquid of low solubility and low surface activity particulately dispersed in a second liquid, comprising: filtering a sample of said liquids through a porous filter element at a controlled flow rate; pressing a pad impregnated with an oil-soluble, water-insoluble dye against the upstream surface of the element; and removing said pad and observing the color stain on the surface of said element which was contiguous with said pad.
Claim 3
Dependent Claim
37 words
A method according to claim 1 wherein the process in preparing said dye-impregnated pad comprises the steps of: applying an organic solvent containing an oil-soluble, water insoluble dye to a pad; and removing said solvent by evaporation.
Claim 4
Dependent Claim
14 words
A method according to claim 2 wherein said pressing is at a preselected pressure.
Claim 5
Dependent Claim
14 words
A method according to claim 3 wherein said pressing is of a predetermined duration.
Claim 6
Dependent Claim
26 words
A method according to claim 4 wherein a method for preparing said sample of said mixture before filtering comprises: adding a surfactant; and agitating the sample.
Claim 7
Dependent Claim
17 words
A method according to claim 5 wherein said first and second liquids are oil and water, respectively.
Claim 8
Dependent Claim
17 words
A method according to claim 6 wherein said pressing is at a force of about 3000 pounds.
Claim 9
Dependent Claim
16 words
A method according to claim 7 wherein the duration of said pressing is about two minutes.
Claim 10
Dependent Claim
26 words
A method according to claim 8 wherein the sample is about 250 ml at a flow rate controlled to cause filtering between 30 and 50 seconds.
Claim 11
Independent Claim
101 words
A method for determining the presence of a first liquid of low solubility and low surface activity particulately dispersed in a second liquid, comprising: filtering a sample of said liquids through a porous filter element having a prefilter on the upstream surface at a controlled flow rate, said prefilter having a polycarbonate membrane of uniform, straight-through cylindrical pores; removing said prefilter from said element; pressing a pad impregnated with an oil-soluble, water-insoluble dye against the upstream surface of the element; and removing said pad and observing the color stain on the surface of said element which was contiguous with said pad.
Claim 12
Independent Claim
101 words
A method for determining the presence of a first liquid of low solubility and low surface activity particulately dispersed in a second liquid, comprising: filtering a sample of said liquids through a porous filter element having a prefilter on the upstream surface at a controlled flow rate, said prefilter having a polycarbonate membrane of uniform, straight-through cylindrical pores; removing said prefilter from said element; pressing a pad impregnated with an oil-soluble, water-insoluble dye against the upstream surface of the element; and removing said pad and observing the color stain on the surface of said element which was contiguous with said pad.
Claim 13
Dependent Claim
37 words
A method according to claim 10 wherein the process in preparing said dye-impregnated pad comprises the steps of: applying an organic solvent containing an oil-soluble, water insoluble dye to a pad; and removing said solvent by evaporation.
Claim 14
Dependent Claim
14 words
A method according to claim 11 wherein said pressing is at a preselected pressure.
Claim 15
Dependent Claim
14 words
A method according to claim 12 wherein said pressing is of a predetermined duration.
Claim 16
Dependent Claim
26 words
A method according to claim 13 wherein a method for preparing the sample of said mixture before filtering comprises: adding a surfactant; and agitating the sample.
Claim 17
Dependent Claim
17 words
A method according to claim 14 wherein said first and second liquids are oil and water, respectively.
Claim 18
Dependent Claim
17 words
A method according to claim 15 wherein said pressing is at a force of about 3000 pounds.
Claim 19
Dependent Claim
16 words
A method according to claim 16 wherein the duration of said pressing is about two minutes.
Claim 20
Dependent Claim
26 words
A method according to claim 17 wherein the sample is about 250 ml at a flow rate controlled to cause filtering between 30 and 50 seconds.
Claim 21
Independent Claim
83 words
A method for determining the presence of a first liquid of low solubility and low surface activity particulately dispersed in a second liquid, comprising: filtering a sample of said liquids through a porous filter element at a controlled flow rate; pressing a pad impregnated with an oil-soluble, water-insoluble dye interposed by a white intermediate pad against the upstream surface of the element; and removing said intermediate pad and observing the color stain on the surface thereof which was contiguous with said dye-impregnated pad.
Claim 22
Independent Claim
83 words
A method for determining the presence of a first liquid of low solubility and low surface activity particulately dispersed in a second liquid, comprising: filtering a sample of said liquids through a porous filter element at a controlled flow rate; pressing a pad impregnated with an oil-soluble, water-insoluble dye interposed by a white intermediate pad against the upstream surface of the element; and removing said intermediate pad and observing the color stain on the surface thereof which was contiguous with said dye-impregnated pad.
Claim 23
Dependent Claim
36 words
A method according to claim 19 wherein the process in preparing said dye-impregnated pad comprises the steps of: applying an organic solvent containing an oil-soluble, water-insoluble dye to a pad; and removing said solvent by evaporation.
Claim 24
Dependent Claim
14 words
A method according to claim 20 wherein said pressing is at a preselected pressure.
Claim 25
Dependent Claim
14 words
A method according to claim 21 wherein said pressing is of a predetermined duration.
Claim 26
Dependent Claim
26 words
A method according to claim 22 wherein a method for preparing the sample of said mixture before filtering comprises: adding a surfactant; and agitating the sample.
Claim 27
Dependent Claim
14 words
A method according to claim 23 wherein said liquid mixture is water and oils.
Claim 28
Dependent Claim
17 words
A method according to claim 24 wherein said pressing is at a force of about 6000 pounds.
Claim 29
Dependent Claim
16 words
A method according to claim 25 wherein the duration of said pressing is about two minutes.
Claim 30
Dependent Claim
26 words
A method according to claim 26 wherein the sample is about 500 ml at a flow rate controlled to cause filtering between 60 and 100 seconds.
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) | 1980-01-25 | 1980-07-26 | 1981-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-01-25 | 1984-07-26 | 1985-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-01-25 | 1988-07-26 | 1989-01-25 | $7700.00 | Window Closed / Lapsed |