US3853501A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removal of radioactive radon daughters from air
Assignee: Radon Dev Corp
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Filing: 1973-07-16
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Granted: 1974-12-10
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Expires: 1993-07-16
Abstract
Abstract An improved process for controlling radioactive radon daughters in the air in a working environment in a mine or during ore processing is described. The described process involving a filter for water contaminated with radon daughters is used in conjunction with air cleaning systems which employ water as a trap for radon daughters. The filter medium involves use of granular substrate which has been dried and oil-wetted with a normally-liquid hydrocarbon material.
Inventors
- 👤 C Stringer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:33
CPC Classifications
G; G21; G21F; G21F9/00; G21F9/02; B; B01; B01D; B01D47/00; Y; Y10; Y10S; Y10S454/00; Y10S454/909; Y10S55/00; Y10S55/09
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
86 words
IN THE METHOD FOR REMOVINB RADIOACTIVE RADON DAUGHTERS FROM AIR WHICH COMPRISES FILTERING AIR CONTAMINATED WITH RADON DAUGHTERS THROUGH A WATER-WETTED FILTER TO CAPTURE THE RADON DAUGHTERS IN THE WATER, THE IMPROVEMENT WHICH COMPRISES: CIRUCLATING THE WATER CONTAIMINATED WITH THE CAPTURED RANDON DAUGHTERS THROUGH FILTER MEDIUM COMPRISING A WATERINSOLUBLE GRANULAR SUBSTRATE WHEREIN THE SURFACE OF THE SUBSTRATE HAS BEEN DRIED OF WATER AND THEN WETTED WITH A NORMALLY LIQUID HYDROCARBIN; AND RETURNING THE FILTETED WATER TO AGAIN WET THE AIR FILTER AND CAPTURE ADDITIONAL RANDON DAUGHTERS.
Claim 2
Dependent Claim
86 words
IN THE METHOD FOR REMOVINB RADIOACTIVE RADON DAUGHTERS FROM AIR WHICH COMPRISES FILTERING AIR CONTAMINATED WITH RADON DAUGHTERS THROUGH A WATER-WETTED FILTER TO CAPTURE THE RADON DAUGHTERS IN THE WATER, THE IMPROVEMENT WHICH COMPRISES: CIRUCLATING THE WATER CONTAIMINATED WITH THE CAPTURED RANDON DAUGHTERS THROUGH FILTER MEDIUM COMPRISING A WATERINSOLUBLE GRANULAR SUBSTRATE WHEREIN THE SURFACE OF THE SUBSTRATE HAS BEEN DRIED OF WATER AND THEN WETTED WITH A NORMALLY LIQUID HYDROCARBIN; AND RETURNING THE FILTETED WATER TO AGAIN WET THE AIR FILTER AND CAPTURE ADDITIONAL RANDON DAUGHTERS.
Claim 3
Dependent Claim
29 words
The method of claim 1 wherein the water-insoluble substrate is sand having a particle size such that it passes a 20-mesh screen and is retained on a 90-mesh screen.
Claim 4
Dependent Claim
14 words
The method of claim 1 wherein the normally liquid hydrocarbon is an aromatic hydrocarbon.
Claim 5
Dependent Claim
29 words
The method of claim 3 wherein the aromatic hydrocarbon is blended with from about 20 percent to about 40 percent by volume mineral oil to form the normally-liquid hydrocarbon.
Claim 6
Dependent Claim
35 words
The method of claim 4 wherein the normally liquid hydrocarbon is about 20 percent to about 40 percent by volume mineral oil and, correspondingly, from about 80 percent to about 60 percent by volume benzene.
Claim 7
Dependent Claim
10 words
The method of claim 5 wherein the substrate is sand.
Claim 8
Dependent Claim
38 words
The method of claim 1 wherein the filter medium comprises a primary filter medium of the water-insoluble granular substrate and a supplementary filter medium consisting of oil-wettable plastic pellets which have been wetted with a normally liquid hydrocarbon.
Claim 9
Dependent Claim
20 words
The method of claim 7 wherein the granular substrate is sand and the plastic pellets are made of cellulose acetate.
Claim 10
Dependent Claim
42 words
The method of claim 8 wherein the normally liquid hydrocarbon is a mixture of about 80 percent to about 60 percent, by volume, an aromatic hydrocarbon and, correspondingly, from about 20 percent to about 40 percent by volume of another liquid hydrocarbon.
Claim 11
Dependent Claim
19 words
The method of claim 9 wherein the aromatic hydrocarbon is benzene and the other liquid hydrocarbon is mineral oil.
Claim 12
Independent Claim
81 words
A method for preparing a filter medium for use in a water scrubbing system removing radon daughter contamination from air which comprises: a. drying a water-insoluble granular substrate at a temperature of at least about 150*F; b. contacting the dried substrate with an excess of a normally liquid hydrocarbon before the substrate with an excess is cooled to wet the substrate surface with the hydrocarbon; and c. removing the excess liquid hydrocarbon to recover the oil-wetted substrate as the filter medium.
Claim 13
Independent Claim
81 words
A method for preparing a filter medium for use in a water scrubbing system removing radon daughter contamination from air which comprises: a. drying a water-insoluble granular substrate at a temperature of at least about 150*F; b. contacting the dried substrate with an excess of a normally liquid hydrocarbon before the substrate with an excess is cooled to wet the substrate surface with the hydrocarbon; and c. removing the excess liquid hydrocarbon to recover the oil-wetted substrate as the filter medium.
Claim 14
Dependent Claim
15 words
The method of claim 11 wherein the drying of the substrate takes place under vacuum.
Claim 15
Dependent Claim
42 words
The method of claim 11 wherein the filter medium consists of a supplementary substrate consisting of oil-wettable plastic particles and a primary oil-wetted substrate consisting of a granular inorganic material wherein the primary substrate is placed on top of the secondary substrate.
Claim 16
Dependent Claim
20 words
The method of claim 13 wherein the supplementary substrate are cellulose acetate beads and the second substrate is granular sand.
Claim 17
Dependent Claim
20 words
The method of claim 11 wherein the normally liquid hydrocarbon is benzene, toluene, hexane, kerosene, mineral oil, or mixtures thereof.
Claim 18
Dependent Claim
18 words
The method of claim 15 wherein the normally liquid hydrocarbon is a mixture of benzene and mineral oil.
Claim 19
Dependent Claim
70 words
A filter adapted for use in a process for the removal of radon daughter contamination from air, which system include wash water contaminated with said radon daughters, the filter which comprises: a. a body to contain a filter medium, the body having a water inlet and water outlet opening; b. a filter medium comprising a granular substrate, the surface of the substrate having been oil-wetted with a normally liquid hydrocarbon.
Claim 20
Dependent Claim
70 words
A filter adapted for use in a process for the removal of radon daughter contamination from air, which system include wash water contaminated with said radon daughters, the filter which comprises: a. a body to contain a filter medium, the body having a water inlet and water outlet opening; b. a filter medium comprising a granular substrate, the surface of the substrate having been oil-wetted with a normally liquid hydrocarbon.
Claim 21
Dependent Claim
33 words
The filter of claim 17 wherein the granular substrate is a primary filter medium and the filter medium includes as a supplementary filter, oil-wettable plastic beads surface wetted with the normally liquid hydrocarbon.
Claim 22
Dependent Claim
20 words
The filter of claim 18 wherein the granular substrate is sand and the supplementary substrate consists of cellulose acetate pellets.
Claim 23
Dependent Claim
14 words
The filter of claim 19 whrein the normally liquid hydrocarbon is an aromatic hydrocarbon.
Claim 24
Dependent Claim
25 words
The filter of claim 20 wherein the aromatic hydrocarbon includes from about 20 percent to about 40 percent by volume of another normally liquid hydrocarbon.
Claim 25
Dependent Claim
18 words
The filter of claim 21 wherein the aromatic hydrocarbon is benzene and the other hydrocarbon is mineral oil.
Claim 26
Dependent Claim
14 words
The filter of claim 17 wherein the normally liquid hydrocarbon is an aromatic hydrocarbon.
Claim 27
Dependent Claim
25 words
The filter of claim 23 wherein the aromatic hydrocarbon contains from about 20 percent to about 40 percent by volume of another normally liquid hydrocarbon.
Claim 28
Dependent Claim
18 words
The filter of claim 24 wherein the aromatic hydrocarbon is benzene and the other hydrocarbon is mineral oil.
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Cited
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Cited
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-09 | 1978-06-10 | 1978-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-09 | 1982-06-10 | 1982-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-09 | 1986-06-10 | 1986-12-10 | $7700.00 | Window Closed / Lapsed |