Ionization detector
AssigneeGulf & Western Manufacturing Company (Systems)
InventorElias E. Solomon
Life of this patent
Estimating the term…
Abstract
An ionization detecting fire alarm device that comprises a double chamber structure, a source disposed in at least one of the chambers and a vernier adjusting screw electrode protruding into one chamber. The chamber containing the adjustable electrode is more open to the atmosphere than the other chamber, porting is provided between chambers and detection occurs by sensing the rate of change of ionization current in the chamber structure. The source or sources, one being in each chamber, is a beta source such as a nickel 63 source. A change in ionization current is detected by a unique circuit of this invention which comprises a programmable unijunction transistor oscillator circuit.
Claims19
An ionization detector comprising;
- a structure defining at least one chamber having means for receiving gases from outside of the chamber,
- at least a pair of fixed electrodes associated with and at least in part defining the chamber and spaced from one another,
- means including a radioactive source disposed in the chamber for establishing an ionization current in the chamber between the fixed electrodes,
- an adjustable particle capturing member contained in the chamber between the fixed electrodes and movable to alter the ionization current,
- means for supporting said particle capturing member independent of either fixed electrode with said member having an end extending into the chamber, the exposed area of said end within the chamber being variable to vary the number of particles captured thereby finely adjusting the ionization current,
- and means coupled from one of the fixed electrodes for detecting changes in the ionization current.
An ionization detector comprising;
- a chamber structure including means defining a first chamber having means for receiving gases from external of the first chamber, means defining a second chamber also having means for receiving gases from external of the second chamber, and common boundary means between chambers having means for permitting the communicating of gases directly between chambers, and including a common electrode,
- fixed electrode means associated with each chamber and spaced from each other and also from the common electrode,
- means including a radioactive source disposed in at least the first chamber for establishing an ionization current in the chamber structure,
- an adjustable electrode contained in one of said first and second chambers for adjusting the ionization current,
- and means coupled from the fixed electrode means for detecting changes in the ionization current.
A circuit for connection to an ionization chamber to detect variations in the ionization current in the chamber comprising;
- means for receiving a signal from an electrode of the chamber including an input transistor circuit having an output terminal,
- first supervisory circuit means including an oscillator circuit and a light source coupled from and operated from the oscillator circuit to light the light source at a set repetition rate during alarm and no alarm conditions, said oscillator circuit coupled directly from the output terminal of the input transistor circuit,
- and second circuit means coupled in parallel with the first supervisory circuit means including a delay circuit and a trigger circuit coupled in series directly from the output terminal of the input transistor circuit and operable to trigger the trigger circuit when an alarm condition exists,
- said first supervisory circuit means being responsive to a first minimum voltage level to operate the light source and said second circuit means being responsive to a second higher voltage level indicative of an alarm condition.
Dependencies are inferred from the claim text.