US3915646A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and means for quantitative analysis of sulfuric acid-containing gases
Assignee: Cabot Corp
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Filing: 1974-09-30
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Granted: 1975-10-28
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Expires: 1994-09-30
Abstract
Abstract There is disclosed a method and means for the quantitative analysis of sulfuric acid contained as a vapor or aerosol in a sample gas. The sample gas is contacted with a water extractant having a substantial exposed surface, thereby to collect the sulfuric acid component therein. The resulting water/sulfuric acid solution is diluted with a further amount of water and the electrical conductivity of the resulting liquid aliquot is measured, said conductivity being related to the concentration of sulfuric aicd therein.
Inventors
- 👤 Bernard Harris
- 👤 Lorenzo Willard Richards
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:35
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/416; G01N27/4162; G01N33/00; G01N33/0004; G01N33/0009; G01N33/0027; G01N33/0036; G01N33/0042; Y; Y02; Y02A; Y02A50/00; Y02A50/20; Y10; Y10T; Y10T436/00; Y10T436/10; Y10T436/100833; Y10T436/15; Y10T436/156666
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
132 words
A METHOD FOR THE QUANTITATIVE ANALYSIS OF SULFURIC ACID CONTAINED AS AN AEROSOL OR VAPOR IN A CARRIER GAS WHICH COMPRISES: A. PROVIDING AN ENCLOSED COLLECTION ZONE HAVING AN OUTLET COMPRISING A GAS PERMEABLE POROUS WATER WETTABLE AND INERT FILTER MEDIUM, B. WETTING SAID FILTER MEDIUM WITH A SMALL KNOWN QUANTITY OF LIQUID WATER EXTRACTANT TO PROVIDE SAID WATER EXTRACTANT ENTRAINED IN LIQUID FORM IN THE FILTER MEDIUM AND HAVING A SUBSTANTIALY EXPOSED SURFACE, C. INTRODUCING SAID CARRIER GAS INTO SAID ENCLOSED COLLECTION ZONE TO CAUSE CONTACT THEREOF WITH SAID WETTED POROUS FILTER MDIUM: D. BACKWASHING SAID FILTER MEDIUM FROM THE DOWNSTREAM SIDE THEREOF WITH AN ADDITIONAL KNOWN QUANTITY OF WATER EXTRACTANT TO PROVIDE A VOLUME OF SULFURIC ACID-CONTAINING AQUEOUS ALIQUOT, AND E. DETERMINING THE ELECTRICAL CONDUCTIVITY AND TEMPERATURE OF SAID ALIQUOT.
Claim 2
Independent Claim
132 words
A METHOD FOR THE QUANTITATIVE ANALYSIS OF SULFURIC ACID CONTAINED AS AN AEROSOL OR VAPOR IN A CARRIER GAS WHICH COMPRISES: A. PROVIDING AN ENCLOSED COLLECTION ZONE HAVING AN OUTLET COMPRISING A GAS PERMEABLE POROUS WATER WETTABLE AND INERT FILTER MEDIUM, B. WETTING SAID FILTER MEDIUM WITH A SMALL KNOWN QUANTITY OF LIQUID WATER EXTRACTANT TO PROVIDE SAID WATER EXTRACTANT ENTRAINED IN LIQUID FORM IN THE FILTER MEDIUM AND HAVING A SUBSTANTIALY EXPOSED SURFACE, C. INTRODUCING SAID CARRIER GAS INTO SAID ENCLOSED COLLECTION ZONE TO CAUSE CONTACT THEREOF WITH SAID WETTED POROUS FILTER MDIUM: D. BACKWASHING SAID FILTER MEDIUM FROM THE DOWNSTREAM SIDE THEREOF WITH AN ADDITIONAL KNOWN QUANTITY OF WATER EXTRACTANT TO PROVIDE A VOLUME OF SULFURIC ACID-CONTAINING AQUEOUS ALIQUOT, AND E. DETERMINING THE ELECTRICAL CONDUCTIVITY AND TEMPERATURE OF SAID ALIQUOT.
Claim 3
Dependent Claim
73 words
The method of claim 1 wherein the original sample gas is ambient air comprising sulfuric acid in aerosol form and wherein said sample gas is pretreated by, seriatim, flowing thereof through a porous filter medium adapted to separate said sulfuric acid aerosol and other particulate matter therefrom and flowing a dry inert gas stream through said sulfuric acid laden filter medium to produce said carrier gas containing said sulfuric acid in vapor form.
Claim 4
Dependent Claim
28 words
The method of claim 1 wherein said determinations of temperature and conductivity provide electrical signals which are integrated so as to temperature compensate the conductivity of the aliquot.
Claim 5
Dependent Claim
23 words
The method of claim 1 wherein said backwashing of the filter medium is accomplished in a plurality of serial, separate and distinct steps.
Claim 6
Dependent Claim
113 words
Apparatus for the quantitative analysis of sulfuric acid contained as an aerosol or vapor in a carrier gas which comprises: A. an enclosure having an outlet comprising a gas permeable, porous, water wettable and inert filter element, means to deliver a known small quantity of liquid water extractant sufficient to wet said filter element, means to deliver an additional known quantity of backwashing water extractant to the downstream side of said filter element and means to deliver a sulfuric acid-containing carrier gas into said enclosure; B. a conductivity measuring chamber adapted to receive a volume of liquid aliquot from said enclosure of (A) and comprising an electrical conductivity cell and temperature sensing means.
Claim 7
Dependent Claim
113 words
Apparatus for the quantitative analysis of sulfuric acid contained as an aerosol or vapor in a carrier gas which comprises: A. an enclosure having an outlet comprising a gas permeable, porous, water wettable and inert filter element, means to deliver a known small quantity of liquid water extractant sufficient to wet said filter element, means to deliver an additional known quantity of backwashing water extractant to the downstream side of said filter element and means to deliver a sulfuric acid-containing carrier gas into said enclosure; B. a conductivity measuring chamber adapted to receive a volume of liquid aliquot from said enclosure of (A) and comprising an electrical conductivity cell and temperature sensing means.
Claim 8
Dependent Claim
13 words
The apparatus of claim 5 wherein said filter element is a glass frit.
Claim 9
Dependent Claim
58 words
The apparatus of claim 5 wherein said enclosure of (A) is disposed substantially vertically, said filter element is disposed across the interior of said enclosure to define an upper filter washing chamber and a lower collection chamber and wherein each of said means to deliver water extractant is disposed to discharge said water extractant into said upper chamber.
Claim 10
Dependent Claim
57 words
The apparatus of claim 7 wherein said upper washing chamber is additionally equipped with inert gas pressurizing means and said lower collection chamber is equipped with pressure relieving means, said pressurizing and relieving means coacting to aid in the flow of water extractant from said washing chamber through said porous filter element and into said collection chamber.
Claim 11
Dependent Claim
69 words
The apparatus of claim 5 wherein said temperature sensing means is a thermistor, wherein said thermistor and said conductivity cell form two variable resistor elements in a Wheatstone bridge arrangement and wherein the voltage required to null said Wheatstone bridge arrangement is employed as the output signal to a transducer, said transducer thereby displaying the temperature compensated conductivity of a volume of liquid contained in said chamber of (B).
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) | 1978-10-27 | 1979-04-28 | 1979-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-27 | 1983-04-28 | 1983-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-27 | 1987-04-28 | 1987-10-28 | $7700.00 | Window Closed / Lapsed |