Electrode assembly for combustion products detector
First Claim
1. An electrode assembly for a combustion product detector which includes means defining a cylindrical ionization chamber having an axis and a first electrode therein and having openings allowing the introduction of ambient air and products of combustion thereinto and a source of radiation disposed within the ionization chamber, said assembly comprising a flat plate-like second electrode mounted in the ionization chamber non-coaxially therewith and spaced from the first electrode, a flat plate-like third electrode disposed in the ionization chamber, and insulating means closing the space between said second and third electrodes around the entire perimeter thereof and maintaining said third electrode spaced from said first and second electrodes for cooperation respectively therewith to define a sampling zone and a reference zone within the ionization chamber, said third electrode having a small opening therein providing the sole communication between said reference zone and said sampling zone.
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Accused Products
Abstract
This electrode assembly includes two relatively large-diameter, parallel conductive discs spaced apart by an annular insulator which has peripheral flanges respectively encompassing the perimeters of the discs. The assembly is adapted to be disposed in an ionization chamber formed by a printed circuit board and a conductive cup mounted thereon. One of the discs has conductive mounting legs adapted to be snap-fitted into complementary openings in the circuit board for spacing the disc from the board a distance sufficient to permit the mounting of associated electronic components therebetween. Both discs have pronged attachment apertures adapted for one-way press-fitting engagement with corresponding attachment posts on the insulating body, one disc having a central aperture for mounting an associated radioactive source thereon. The other disc cooperates with the one disc to define a reference zone therebetween and cooperates with the metal cup to define a sampling zone of the ionization chamber.
19 Citations
20 Claims
- 1. An electrode assembly for a combustion product detector which includes means defining a cylindrical ionization chamber having an axis and a first electrode therein and having openings allowing the introduction of ambient air and products of combustion thereinto and a source of radiation disposed within the ionization chamber, said assembly comprising a flat plate-like second electrode mounted in the ionization chamber non-coaxially therewith and spaced from the first electrode, a flat plate-like third electrode disposed in the ionization chamber, and insulating means closing the space between said second and third electrodes around the entire perimeter thereof and maintaining said third electrode spaced from said first and second electrodes for cooperation respectively therewith to define a sampling zone and a reference zone within the ionization chamber, said third electrode having a small opening therein providing the sole communication between said reference zone and said sampling zone.
- 3. An electrode assembly for a combustion product detector which includes means defining a cylindrical ionization chamber having an axis and a first electrode therein and having openings allowing the introduction of ambient air and products of combustion thereinto and a source of radiation disposed within the ionization chamber, said assembly comprising a second electrode mounted in the ionization chamber non-coaxially therewith and spaced from the first electrode and having attachment means, a third electrode disposed in the ionization chamber and having attachment means, and an insulating body having first and second attachment structure respectively disposed on opposite sides thereof, said first and second attachment structure being respectively adapted for press-fitting engagement with the attachment means of said second and third electrodes for secure attachment thereof to said insulating body in an assembled condition wherein said insulating body closes the space between said second and third electrodes around the entire perimeter thereof and maintains said third electrode spaced from said first and second electrodes for cooperation respectively therewith to define a sampling zone and a reference zone within the ionization chamber, said third electrode having a small opening therein providing the sole communication between said reference zone and said sampling zone.
- 7. An electrode assembly for a combustion product detector which includes a printed circuit board and a conductive housing forming a first electrode and mounted on the circuit board for cooperation therewith to define a cylindrical ionization chamber having an axis and having openings allowing the introduction of ambient air and products of combustion thereinto and a source of radiation disposed within the ionization chamber, said assembly comprising a flat plate-like second electrode having an attachment aperture therein, means mounting said second electrode in the ionization chamber non-coaxially therewith substantially parallel to the circuit board and spaced therefrom and from the first electrode, a flat plate-like third electrode disposed in the ionization chamber and having an attachment aperture therein, and an insulating body having an opening therethrough and including first and second attachment posts respectively extending from opposite sides thereof, said first attachment post being adapted for press-fitted engagement in said attachment aperture of said second electrode securely to attach said insulating body thereto, said second attachment post of said insulating body being adapted for press-fitting engagement in said attachment aperture of said third electrode securely to fasten said insulating body thereto, whereby said insulating body closes the space between said second and third electrodes around the entire perimeter thereof and maintains said third electrode spaced from said first and second electrodes for cooperation respectively therewith to define a sampling zone and a reference zone within the ionization chamber, said third electrode having a small access opening therein cooperating with said opening in said insulating body for providing the sole communication between said reference zone and said sampling zone.
- 17. An electrode assembly for a combustion product detector which includes a printed circuit board and a conductive housing forming a first electrode and mounted on the circuit board for cooperation therewith to define an ionization chamber and having openings allowing the introduction of ambient air and products of combustion thereinto and a source of radiation disposed within the ionization chamber, said assembly comprising a flat plate-like second electrode having an attachment aperture therein, means mounting said second electrode in the ionization chamber substantially parallel to the circuit board and spaced therefrom and from the first electrode, a flat plate-like third electrode disposed in the ionization chamber and having an attachment aperture therein, and an insulating body having an opening therethrough and including first and second spaced-apart flat mounting surfaces on opposite sides thereof and first and second attachment posts respectively extending from said mounting surfaces, first and second retaining flanges respectively integral with said first and second mounting surfaces and extending therefrom substantially normal thereto around the entire perimeter thereof, said second electrode being disposed against said first mounting surface within said first peripheral flange with said first attachment post being disposed in press-fitted engagement in said attachment aperture of said second electrode securely to attach said insulating body thereto, said third electrode being disposed against said second mounting surface within said second peripheral flange with said second attachment post being disposed in press-fitted engagement in said attachment aperture of said third electrode securely to fasten said insulating body thereto, whereby said insulating body maintains said third electrode spaced from said first and second electrodes for cooperation respectively therewith to define a sampling zone and a reference zone within the ionization chamber, said third electrode having a small access opening therein cooperating with said opening in said insulating body for providing communication between said reference zone and said sampling zone.
Specification