US4226369A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Means and method for the destruction of particles entrained in a gas stream
Assignee: United States Department of Energy
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Filing: 1978-08-17
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Granted: 1980-10-07
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Expires: 1998-08-17
Abstract
Abstract An apparatus and method for the destruction of particles entrained in a gas stream are disclosed. Destruction in the context of the subject invention means the fragmentation and/or vaporization of particles above a certain size limit. The subject invention contemplates destroying such particles by exposing them to intense bursts of laser light, such light having a frequency approximately equal to or less than the mean size of such particles. This invention is particularly adopted to the protection of turbine blades in open cycle coal-fired turbine systems. Means for introducing various chemical species and activating them by exposure to laser light are also disclosed.
Inventors
- 👤 Thomas E. Botts
- 👤 James R. Powell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 13:11
CPC Classifications
F; F02; F02C; F02C3/00; F02C3/20; F02C3/30; B; B01; B01D; B01D49/00; F02C3/26; F23; F23J; F23J15/00; F23J15/02; Y; Y02; Y02E; Y02E20/00; Y02E20/16
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
90 words
A method for the production of a gas stream significantly free of particles larger than about 2 to 5 microns said method comprising the step of: (a) producing a particulate laden gas stream by the combustion of coal; (b) passing said particulate laden gas stream through a cavity, said cavity having associated with it laser means for providing illumination of appropriate wavelength and energy density to destroy particles, and having window means for admitting said laser illumination; and, (c) exposing a significant portion of said particles to said laser illumination.
Claim 2
Independent Claim
90 words
A method for the production of a gas stream significantly free of particles larger than about 2 to 5 microns said method comprising the step of: (a) producing a particulate laden gas stream by the combustion of coal; (b) passing said particulate laden gas stream through a cavity, said cavity having associated with it laser means for providing illumination of appropriate wavelength and energy density to destroy particles, and having window means for admitting said laser illumination; and, (c) exposing a significant portion of said particles to said laser illumination.
Claim 3
Dependent Claim
19 words
A method as described in claim 1 wherein said gas stream is used after step b for powering turbines.
Claim 4
Dependent Claim
25 words
A method as described in claim 1 wherein the gas stream is pre-filtered to limit the maximum size of the particles to approximately 10 microns.
Claim 5
Dependent Claim
19 words
A method as described in claim 1 wherein said laser illumination has a wavelength less than approximately 20 microns.
Claim 6
Dependent Claim
34 words
A method as described in claim 1 or in claim 4 wherein said particles are exposed to said laser illumination having an energy density per pulse greater than approximately 5.1×10 -4 joules/cm 2 .
Claim 7
Independent Claim
248 words
An apparatus for the production of a gas stream substantially free of particles larger than about 2 to 5 microns; said apparatus comprising: (a) combustion means for producing a particulate laden gas stream by the combustion of coal; (b) particle destruction apparatus further comprising: (b1) structure means for containing such a particulate laden gas stream within a cavity; (b2) intake and exhaust means for maintaining the flow of such a particulate laden gas stream through said cavity; (b3) laser means for providing illumination of appropriate wavelength and energy density to a significant portion of said cavity at a sufficient pulse rate whereby a significant portion of the particles in the gas stream will be destroyed by exposure to said illumination as they pass through said cavity; and, (b4) window means associated with said cavity for admitting said illumination into said cavity, said window means further comprising windows formed of material having a low absorption of said illumination so as to reduce the amount of energy absorbed by said windows and thereby reduce the possibility of damage to said windows; and, (c) means, connecting said combustion means with said intake means of said particle destruction apparatus, for conducting said particulate laden gas stream from said combustion means to said intake means whereby the particulate laden gas stream will flow through said particle destruction apparatus and a significant portion of the particles will be destroyed producing the gas stream significantly free of particles larger than about 2 to 5 microns.
Claim 8
Independent Claim
248 words
An apparatus for the production of a gas stream substantially free of particles larger than about 2 to 5 microns; said apparatus comprising: (a) combustion means for producing a particulate laden gas stream by the combustion of coal; (b) particle destruction apparatus further comprising: (b1) structure means for containing such a particulate laden gas stream within a cavity; (b2) intake and exhaust means for maintaining the flow of such a particulate laden gas stream through said cavity; (b3) laser means for providing illumination of appropriate wavelength and energy density to a significant portion of said cavity at a sufficient pulse rate whereby a significant portion of the particles in the gas stream will be destroyed by exposure to said illumination as they pass through said cavity; and, (b4) window means associated with said cavity for admitting said illumination into said cavity, said window means further comprising windows formed of material having a low absorption of said illumination so as to reduce the amount of energy absorbed by said windows and thereby reduce the possibility of damage to said windows; and, (c) means, connecting said combustion means with said intake means of said particle destruction apparatus, for conducting said particulate laden gas stream from said combustion means to said intake means whereby the particulate laden gas stream will flow through said particle destruction apparatus and a significant portion of the particles will be destroyed producing the gas stream significantly free of particles larger than about 2 to 5 microns.
Claim 9
Dependent Claim
23 words
The apparatus of claim 6 wherein said conducting means further comprises preliminary means for the removal of particles larger than about 10 microns.
Claim 10
Dependent Claim
18 words
An apparatus as described in claim 6 wherein said laser illumination has a wavelength less than 20 microns.
Claim 11
Dependent Claim
18 words
An apparatus as described in claim 8 wherein said laser means has a wavelength of approximately 10 microns.
Claim 12
Dependent Claim
28 words
An apparatus as described in claim 9 wherein said windows are formed from a material chosen from the group consisting of zinc selinide, germanium, gallium arsenide and silicon.
Claim 13
Dependent Claim
21 words
An apparatus as described in claim 10 further comprising means for maintaining said windows at a temperature below approximately 250° C.
Claim 14
Dependent Claim
23 words
An apparatus as described in claim 8 wherein the energy density per pulse of said laser means is approximately 20 joules/cm 2 .
Claim 15
Dependent Claim
19 words
An apparatus as described in claim 8 wherein the pulse length of said laser means is approximately one microsecond.
Claim 16
Dependent Claim
16 words
An apparatus as described in claim 6 wherein said laser means is a CO 2 laser.
Claim 17
Dependent Claim
44 words
An apparatus as described in claim 6 wherein the energy density per pulse within various portions of said cavity which are illuminated is between approximately 5 joules/cm 2 and 100 joules/cm 2 and the pulse length of said laser means is approximately 1 microsecond.
Claim 18
Dependent Claim
32 words
An apparatus as described in claim 6 wherein the volume percentage of said cavity which will be exposed to sufficient laser energy to cause particle destruction is from 50 to 90 percent.
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) | 1983-10-07 | 1984-04-07 | 1984-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-07 | 1988-04-07 | 1988-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-07 | 1992-04-07 | 1992-10-07 | $7700.00 | Window Closed / Lapsed |