Claims
- 1. A method of electrostatically precipitating particles from a gaseous medium carrying the same, comprising:
- passing the medium through a channel in an electrostatic precipitating station wherein said particles are brought into a region containing ions of only one sign, said region including substantially the entire volume in said channel between an ion emitter and a collection electrode;
- generating said supply of ions of one sign in said region by thermionic ion emission from a thermionic ion emitter material comprising the beta phase of Li.sub.2 O . Al.sub.2 O.sub.3 . 2 SiO.sub.2 heated to a temperature sufficient to cause ion emission;
- subjecting said medium to a generally uniform, strong electric field to drive said ions of one sign onto said particles;
- said electric field causing attraction of said charged particles to one or more electrodes having a charge of opposite polarity to thereby precipitate said particles out of the medium.
- 2. A method as defined in claim 1 wherein said temperature is about 800.degree. C.
- 3. A method as defined in claim 1 wherein said ions are generated only in the upstream portion of said precipitating channel.
- 4. A method as defined in claim 1 wherein said ions are generated throughout the length of said precipitating channel.
- 5. A method as defined in claim 1 wherein said ion emitter is heated from an external source.
- 6. A method as defined in claim 1 wherein said ion emitter is heated by the hot gaseous medium.
- 7. A method for electrostatically precipitating particles from a gaseous medium carrying the same, comprising the steps of:
- passing the medium through a precipitating station having a plurality of electrodes including at least one positively charged electrode and at least one negatively charged electrode, selective electrodes being charged to produce a strong electric field within said precipitating station;
- subjecting said medium within said precipitating station to a supply of positive ions produced by a thermionic ion emitting material comprising the beta phase of Li.sub.2 O . Al.sub.2 O.sub.3 . 2 SiO.sub.2 heated to a temperature sufficient to produce said supply of ions;
- said ions charging the particles in said medium so that the magnitude of the attractive force between the particles and said negative electrode increases sufficiently so that the charged particles move toward said negatively charged electrode.
- 8. A method as defined in claim 7, wherein said material is applied to said positively charged electrode.
- 9. A method for removing particles from a gaseous medium at a precipitating station having a plurality of electrodes including at least one anode and at least one cathode, the cathode being adapted to attract particles having a net positive charge, comprising the steps of:
- charging said electrodes to produce a strong electric field within said precipitating station;
- passing the particle containing medium through the electrostatic precipitating station;
- subjecting the medium to ions of one sign produced by a thermionic ion emitter located within the precipitating station, said thermionic ion emitter comprising the beta phase of Li.sub.2 O . Al.sub.2 O.sub.3 . 2 SiO.sub.2 heated to a temperature sufficient to cause ion emission, the ions charging said particles in said medium so that said electric field causes said charged particles to be attracted to an oppositely charged electrode.
- 10. A method as defined in claim 9 wherein said electric field is up to the range of about 12 kV/cm to about 18 kV/cm.
- 11. A method as defined in claim 9 wherein said electrodes comprise generally flat members having arcuate edge portions.
- 12. A method as defined in claim 9 wherein said thermionic ion emitter produces positive ions and is applied to at least one of said positive electrodes.
- 13. A method as defined in claim 9 wherein said temperature is about 800.degree. C.
- 14. Apparatus for removing particles from a gaseous medium passing therethrough, comprising:
- an inlet for receiving and an outlet for expelling the medium;
- a central portion between said inlet and outlet for guiding said medium through the apparatus;
- at least one positivity charged electrode located in said central portion;
- at least one negatively charged electrode located in said central portion for attracting particles having a net positive charge from the medium;
- thermionic ion emitter means comprising the beta phase of Li.sub.2 O . Al.sub.2 O.sub.3 . 2 SiO.sub.2 heated to a temperature sufficient to cause ion emission for producing a supply of positive ions which bombard particles and cause them to be attracted to said negatively charged electrode.
- 15. Apparatus as defined in claim 14 wherein said temperature is about 800.degree. C.
- 16. Apparatus as defined in claim 14 wherein said positively charged electrode has a layer of said thermionic ion emitter material applied thereto.
- 17. Apparatus as defined in claim 14 wherein said positive ion producing means produces said supply of ions adjacent said positively charged electrode.
- 18. Apparatus as defined in claim 14 wherein said electrodes are in the form of generally flat members having curved edge portions.
Parent Case Info
This is a continuation-in-part of our original application, Ser. No. 502,103, filed Aug. 29, 1974 now abandoned.
US Referenced Citations (5)
Foreign Referenced Citations (2)
Number |
Date |
Country |
155,683 |
Mar 1954 |
AU |
1,046,652 |
Oct 1966 |
UK |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
502103 |
Aug 1974 |
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