US4176165A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Treatment of alkyl lead-containing gas stream
Assignee: PPG Industries Inc
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Filing: 1978-11-08
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Granted: 1979-11-27
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Expires: 1998-11-08
Abstract
Abstract Method of removing alkyl lead from air and other gases by contacting said air or other gas with at least a catalytic amount of lead dioxide at temperatures in the range between 60° C. and 225° C.
Inventors
- 👤 William D. Hargett
- 👤 Thorowgood T. Broun
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:04
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/72
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
50 words
A method for treating a gaseous stream containing alkyl lead which comprises contacting the gas stream with at least a catalytic amount of lead dioxide at temperatures in the range between 60° C. and 225° C. for a time sufficient to reduce the alkyl lead content of the gaseous stream.
Claim 2
Independent Claim
50 words
A method for treating a gaseous stream containing alkyl lead which comprises contacting the gas stream with at least a catalytic amount of lead dioxide at temperatures in the range between 60° C. and 225° C. for a time sufficient to reduce the alkyl lead content of the gaseous stream.
Claim 3
Dependent Claim
11 words
The method of claim 1, wherein the gaseous stream is air.
Claim 4
Dependent Claim
40 words
The method of claim 1, wherein the amount of lead dioxide is between 15 square meters surface area of lead dioxide per cubic centimeter gas treated to 350 square meters surface area of lead dioxide per cubic centimeter gas treated.
Claim 5
Dependent Claim
21 words
The method of claim 1, wherein the volatile alkyl lead is a mixture consisting essentially of tetraethyl lead and tetremethyl lead.
Claim 6
Dependent Claim
16 words
The method of claim 1, wherein the alkyl lead is contained in a ventilating air stream.
Claim 7
Dependent Claim
20 words
The method of claim 5, wherein the ventilating air stream contain less than 1 part per hundred of alkyl lead.
Claim 8
Independent Claim
48 words
A method for treating an air stream containing alkyl lead which comprises contacting the air stream with dust from a lead smelting furnace at temperatures in the range between 60° C. and 225° C. for a time sufficient to reduce the alkyl lead content of the air stream.
Claim 9
Independent Claim
48 words
A method for treating an air stream containing alkyl lead which comprises contacting the air stream with dust from a lead smelting furnace at temperatures in the range between 60° C. and 225° C. for a time sufficient to reduce the alkyl lead content of the air stream.
Claim 10
Dependent Claim
31 words
The method of claim 7, wherein the air is mixed with a gas stream from the lead smelting furnace and which further comprises filtering the mixture through bags in a baghouse.
Claim 11
Independent Claim
58 words
A method of treating an air stream containing 17 to 1700 milligrams of alkyl lead per standard cubic meter which comprises contacting the air stream with dust from a lead smelting furnace at a temperature in the range between 60° C. and 225° C. for a time sufficient to reduce the alkyl lead content of the air stream.
Claim 12
Independent Claim
58 words
A method of treating an air stream containing 17 to 1700 milligrams of alkyl lead per standard cubic meter which comprises contacting the air stream with dust from a lead smelting furnace at a temperature in the range between 60° C. and 225° C. for a time sufficient to reduce the alkyl lead content of the air stream.
Claim 13
Dependent Claim
17 words
The method of claim 9, wherein the alkyl lead consists essentially of tetramethyl lead and tetraethyl lead.
Claim 14
Dependent Claim
19 words
The method of claim 9, wherein the alkyl lead content is reduced below 530 milligrams per standard cubic meter.
Claim 15
Independent Claim
60 words
A method for treating a gaseous stream containing alkyl lead which comprises contacting the gas stream with a catalytic amount of lead dioxide in the presence of at least the stoichiometric amount of oxygen at temperatures in the range between 60° C. and 225° C. for a time sufficient to convert the lead in the alkyl lead to lead dioxide.
Claim 16
Independent Claim
60 words
A method for treating a gaseous stream containing alkyl lead which comprises contacting the gas stream with a catalytic amount of lead dioxide in the presence of at least the stoichiometric amount of oxygen at temperatures in the range between 60° C. and 225° C. for a time sufficient to convert the lead in the alkyl lead to lead dioxide.
Claim 17
Dependent Claim
11 words
The method of claim 12, wherein the gaseous stream is air.
Claim 18
Dependent Claim
41 words
The method of claim 12, wherein the catalytic amount of lead dioxide is between 15 square meters surface area of lead dioxide per cubic centimeter gas treated to 350 square meter surface area of lead dioxide per cubic centimeter gas treated.
Claim 19
Dependent Claim
20 words
The method of claim 12, wherein the alkyl lead is a mixture consisting essentially of tetraethyl lead and tetramethyl lead.
Claim 20
Dependent Claim
16 words
The method of claim 12, wherein the alkyl lead is contained in a ventilating air stream.
Claim 21
Independent Claim
66 words
A method for treating an air stream containing alkyl lead which comprises contacting the air stream with lead dioxide containing dust from a lead smelting furnace at temperatures in the range between 60° C. and 225° C. for a time sufficient to convert the lead in the alkyl lead to lead dioxide, the air stream containing at least the stoichiometric amount of oxygen for the conversion.
Claim 22
Independent Claim
66 words
A method for treating an air stream containing alkyl lead which comprises contacting the air stream with lead dioxide containing dust from a lead smelting furnace at temperatures in the range between 60° C. and 225° C. for a time sufficient to convert the lead in the alkyl lead to lead dioxide, the air stream containing at least the stoichiometric amount of oxygen for the conversion.
Claim 23
Dependent Claim
31 words
The method of claim 17, wherein the air is mixed with a gas stream from a lead smelting furnace and which further comprises filtering the mixture through bags in a baghouse.
Claim 24
Dependent Claim
17 words
The method of claim 17, wherein the alkyl lead consists essentially of tetramethyl lead and tetraethyl lead.
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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) | 1982-11-26 | 1983-05-28 | 1983-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-11-26 | 1987-05-28 | 1987-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-11-26 | 1991-05-28 | 1991-11-27 | $7700.00 | Window Closed / Lapsed |