Ionization aerosol detector

Claim 2

An ionization aerosol detection system comprising: first and second electrodes spaced one from the other; a DC voltage source maintaining a charge difference between the electrodes; a radiation source situated between the electrodes and associated with the first electrode, the radiation source emitting particles into the space between the electrodes and the second electrode comprising a wire axially aligned iwht the radiation source; means developing an electric field around the radiation source for focusing the emitted particles into a column generally along a line coaxial with the second electrode; means for exposing a quantity of ambient air to the focused column of emitted particles; means for electrically detecting the change in conductivity between the electrodes resulting from the presence of aerosols between the electrodes; and alarm means responsive to the detecting means when a preset threshold of conductivity is reached.

Claim 3

An ionization aerosol detection system as defined in claim 1 wherein said developing means comprises a housing for the radiation source which is charged to essentially collimate ions emitted therefrom.

Claim 4

An ionization aerosol detection system as defined in claim 1 wherein the first electrode is cylindrically configurated and wherein said radiation source is situated adjacent the cylinder upon the axis thereof, particles emitted from the radiation source having the same charge as the first electrode.

Claim 5

An ionization aerosol detection system comprising an electrical detection circuit which comprises: power supply means; a measuring ionization chamber presenting two spaced electrodes; a fixed resistive element in series with the measuring chamber, the series being directly across the power supply; an amplification-isolation element comprising a MOSFET, the gate of which is electrically connected to a node between the measuring chamber and the fixed resistor, the MOSFET conducting a measurable amount of drain to source current in the steady state and a reduced current when aerosols affect the conductance of the ionization chamber; an inverting element coupled to the output of the MOSFET for monitoring the current therethrough, said inverting element developing an output signal when the current through the MOSFET drops to a predetermined level; an alarm driving switching element responsive to the output signal of the inverting element; and an alarm providing a perceptible indication when the switching element is in the conductive state.

Claim 6

An ionization aerosol detection system comprising an electrical detection circuit which comprises: power supply means; a measuring ionization chamber presenting two spaced electrodes; a fixed resistive element in series with the measuring chamber, the series being directly across the power supply; an amplification-isolation element comprising a MOSFET, the gate of which is electrically connected to a node between the measuring chamber and the fixed resistor, the MOSFET conducting a measurable amount of drain to source current in the steady state and a reduced current when aerosols affect the conductance of the ionization chamber; an inverting element coupled to the output of the MOSFET for monitoring the current therethrough, said inverting element developing an output signal when the current through the MOSFET drops to a predetermined level; an alarm driving switching element responsive to the output signal of the inverting element; and an alarm providing a perceptible indication when the switching element is in the conductive state.

Claim 7

An ionization aerosol detection system as defined in claim 4 wherein said inverting element comprises a solid state inverting operational amplifier.

Claim 10

A method of electronically detecting the presence of aerosols in ambient air as defined in claim 6 wherein said focusing step comprises enveloping the electrodes and radiation source within an axIally symmetrical cavity and electrically charging the cavity with the polarity of the emitted particles.