Ionization Patents (Class 340/629)
  • Patent number: 4364031
    Abstract: An ionization smoke detector containing at least one ionization chamber operated at an extra low voltage or potential. The ionization chamber contains a sensor employing a measuring electrode and a counter electrode. Ambient air has practically free access to the ionization chamber and there are provided one or more radioactive sources for generating ions, a supply voltage source and an electrical circuit for triggering an alarm. The smoke detector possesses increased operational reliability since circuit elements are provided which enable signal reporting to a central station by means of a low-voltage of about 200 volts, however the sensor is operated at an extra low voltage.
    Type: Grant
    Filed: October 20, 1980
    Date of Patent: December 14, 1982
    Assignee: Cerberus AG
    Inventors: Andreas Scheidweiler, Peter Muller
  • Patent number: 4335378
    Abstract: A combustion detection apparatus and method is provided for generating an alarm output when either a first alarm condition or a second alarm condition is present. A first alarm output is generated when a first predetermined concentration of combustion products is continuously present in a region being monitored for a preestablished period of time. A second alarm output is immediately generated when a second predetermined concentration of combustion products is present in the region being monitored. The second predetermined concentration of combustion products represents a relatively greater concentration of combustion products than the first predetermined concentration.
    Type: Grant
    Filed: December 20, 1978
    Date of Patent: June 15, 1982
    Assignee: Emerson Electric Company
    Inventor: Charles Coleman
  • Patent number: 4319234
    Abstract: Smoke detector, comprising a housing the length side of which is several times greater than the width side thereof, incorporating a sensor and a power source; a U-shaped bracket having a base mounted turnable on the top of the housing, and downwardly directed arms, one of which carries a second sensor interconnected with the first sensor and the power source, which is rotatable from a position adjacent the width sides of the housing into a position of parallel spaced relationship to the length side thereof, for accommodation of an upper door edge between the space within the sensor carrying arm and the length side of the housing.
    Type: Grant
    Filed: July 29, 1980
    Date of Patent: March 9, 1982
    Inventor: Royal K. Rice
  • Patent number: 4316184
    Abstract: A photosensor circuit produces a first sensor signal having an amplitude related to the quantity of smoke sensed thereby. An ionization sensor circuit produces a second sensor signal having an amplitude also related to the quantity of smoke sensed thereby. A first circuit provides a first output only when both the sensor signals exceed a first level. A second circuit provides a second output when either of the sensor signals exceeds a second higher level. An alerting-signal generator is coupled to both of the circuits and is responsive to either output to provide an alerting signal.
    Type: Grant
    Filed: July 27, 1979
    Date of Patent: February 16, 1982
    Assignee: Pittway Corporation
    Inventor: Richard A. Nagel
  • Patent number: 4306229
    Abstract: A fire detector comprises a piezo-electric element attached to a vibrating portion which is part of a component constituting the detector. The component having the vibrating function may be a casing or an electrode or any other suitable member. The piezo-electric buzzer is thus incorporated in the detector to form a simple and compact fire detector with an alarm device.
    Type: Grant
    Filed: June 23, 1980
    Date of Patent: December 15, 1981
    Assignee: Nohmi Bosai Kogyo Co., Ltd.
    Inventors: Toru Tamura, Toshiaki Okazaki
  • Patent number: 4305069
    Abstract: This invention is a combination smoke and fire detection and alarm system that comprises a battery powered personal unit and an AC/DC sustaining unit. It provides audible and visual alarms and an emergency light. The personal unit plugs into the sustaining unit for battery charge and provides an additional smoke and fire detector when used in this mode.
    Type: Grant
    Filed: May 31, 1978
    Date of Patent: December 8, 1981
    Inventors: Robert B. Machen, John E. Thompson
  • Patent number: 4300132
    Abstract: A fire alarm having in a single unit a battery and a fire detecting section energized by the battery to detect abnormal environmental conditions such as heat and smoke to provide an output signal. A voltage decrement detecting section detects a voltage decrement of the battery to provide an output signal. A warning unit such as a buzzer is coupled to a switching circuit for operating the warning unit upon reception of the output signal from either the fire detecting section or the voltage decrement detecting section through an input terminal thereof. To reduce power consumption, the system uses a multivibrator having C-MOS IC, inverters.
    Type: Grant
    Filed: February 2, 1979
    Date of Patent: November 10, 1981
    Assignee: Hochiki Corporation
    Inventors: Takeo Arima, Akira Furuyama
  • Patent number: 4287516
    Abstract: A combustion products detection apparatus and method are provided. The apparatus is powered by an energy source which provides a relatively low DC output voltage. This DC voltage is multiplied by a voltage multiplier circuit in conjunction with a first oscillator having an output of a first predetermined frequency. The output voltage of the voltage multiplier circuit is applied to a combustion products sensor circuit. Upon detection of a predetermined concentration of combustion products in the region being monitored by the sensor circuit, a second oscillator is enabled. The second oscillator has an output of a second predetermined frequency which is a greater frequency than the first predetermined frequency. The second predetermined frequency output controls the voltage multiplier circuit when the predetermined concentration of combustion products is present.
    Type: Grant
    Filed: August 23, 1979
    Date of Patent: September 1, 1981
    Assignee: Emerson Electric Co.
    Inventor: Charles Coleman
  • Patent number: 4282520
    Abstract: An ionization smoke detector having two ionization chambers, one completely open to the ambient atmosphere and the other, a reference chamber, in communication with the atmosphere only through a breather tube having a defined length to diameter ratio. The detector employs a piezoelectric horn mounted on a cylindrical tube-like structure and attached to a printed circuit board containing one or more holes opposite the horn element so as to form a resonant chamber. The invention further contemplates a test switch which can be used to determine whether the battery is charged and the circuits are functioning.
    Type: Grant
    Filed: October 25, 1978
    Date of Patent: August 4, 1981
    Inventors: John I. Shipp, Charlie C. Rogers, III
  • Patent number: 4282519
    Abstract: A smoke detection alarm system which has at least one detector and alarm in each of the plurality of areas with an interconnection circuit whereby upon the detection of an abnormal smoke condition in any one of the areas, the annunciator or horn of the detector in the area having the abnormal condition is operated with a steady tone and the annunciators of the other detectors in other areas are operated in an intermittent tone so that an occupant of an area can determine by the sound of the tone from the annunciator whether the abnormal condition is in the area in which he is located or in a remote area.
    Type: Grant
    Filed: October 6, 1977
    Date of Patent: August 4, 1981
    Assignee: Honeywell Inc.
    Inventors: Stephen A. Haglund, Robert L. Payne
  • Patent number: 4280052
    Abstract: The detector uses a single radioactive source, such as a beta ionization source, with a multiple chamber construction. The source is positionable relative to the center or node electrode to provide simple adjustment of ionization in each chamber of say a dual chamber detector. Adjustment may be achieved without altering the geometric volume of the chambers or electrode spacing, but instead by altering the ratio of the source area protruding into each chamber. In one embodiment the center or node electrode is fixed and the source is adjustable in a direction normal to the electrode or by tilting relative to the electrode. In another embodiment the source is fixed and the electrode is adjustable relative to the position of the source. The principles may also be embodied in a three-chamber detector.
    Type: Grant
    Filed: November 9, 1978
    Date of Patent: July 21, 1981
    Inventor: Elias E. Solomon
  • Patent number: 4270123
    Abstract: A fire detector provided with a warning system, a reference element and an analysis element whose impedance varies in the presence of a rise of temperature and/or radiation and/or combustion gas, said reference and analysis elements being connected in series or in parallel and constituting two adjacent arms of a Wheatstone bridge assembly. The other two arms are constituted by resistors if necessary variable while the measuring diagonal or bridge, joins, either the common connecting points of the resistors and said elements, or respectively the ends of the detector elements. This device is distinguished in that the two ends of the bridge (X and Y) are connected respectively to the two inputs of two voltage comparators (A.sub.1 and A.sub.2), mounted in parallel and in reverse, each connected to a warning system (S.sub.1, S.sub.
    Type: Grant
    Filed: February 26, 1979
    Date of Patent: May 26, 1981
    Assignee: Universal Det, S.A.R.L.
    Inventor: Jean-Claude Collard
  • Patent number: 4266220
    Abstract: A self-calibrating obscuration smoke detector is provided along with a method for the operation thereof. A light source and a photodetector are mounted in spaced relation to one another with the output of the photodetector being a function of the amount of light sensed by the detector from the light source. The photodetector analog output is converted into digital signals by an A/D converter and digital signals are then delivered to a digital processor adapted to periodically calibrate the detector and to perform sampling operations between calibrations. Other sensing devices may be connected to the system with automatic self-calibrating capabilities with respect thereto.By using a pair of photodetecting cells directly visible to separate light sources or indirectly visible to a single source, a thermally stable system is provided where one cell provides a reference output for the other cell.
    Type: Grant
    Filed: July 27, 1979
    Date of Patent: May 5, 1981
    Inventor: William J. Malinowski
  • Patent number: 4266218
    Abstract: A circuit for reducing or eliminating the sensitivity of alarm circuitry to false alarms caused by noise occurring synchronously with a 60 Hz line voltage. The 60 Hz line signal is applied to a variable-threshold circuit which produces a 60 Hz clock signal. The clock signal produced by the variable-threshold circuit may be selected to occur at different points during a cycle of the 60 Hz line signal. In response to successive alarm signals, the clock signal produced by the variable-threshold circuit occurs with different phasing relationships to the 60 Hz line signal. Before an alarm indication is made, an alarm signal must be provided by the smoke sensor in response to a plurality of successive samples.
    Type: Grant
    Filed: October 12, 1978
    Date of Patent: May 5, 1981
    Assignee: Cherry Semiconductor Corporation
    Inventor: John J. Kardash
  • Patent number: 4260984
    Abstract: A detecting circuit is responsive to the change in a physical parameter indicative of a fire such as smoke, heat, flame or the like, and a comparator circuit connected to the detecting circuit produces detection pulses in synchronism with an oscillator circuit when the change in the physical parameter exceeds a predetermined amount. A counter circuit counts the detection pulses and produces an output which triggers a switching circuit when a predetermined number of consecutive detection pulses are counted. When triggered, the switching circuit transmits an alarm signal to an alarm receiving panel. Connected between the counter circuit and the switching circuit is a monostable multivibrator having a time constant which is equal to or smaller than the supply voltage rise time constant of the counter circuit so as to prevent the trigger signal from being applied to the switching circuit during the transition period immediately following the connection of the power source.
    Type: Grant
    Filed: March 13, 1980
    Date of Patent: April 7, 1981
    Assignee: Hochiki Corporation
    Inventor: Hiroshi Honma
  • Patent number: 4257039
    Abstract: A smoke detector is battery operated and may employ an ionization chamber and/or an infrared detector. When the alarm circuit is actuated due to the presence of smoke levels above a predetermined value being sensed by the detector, the alarm is actuated and each of the built in lights is illuminated. An auxilliary light energizeable by said detector is adapted to disengage one of said lights electrically and to be energized at the same time the other of said lights is energized.
    Type: Grant
    Filed: December 26, 1978
    Date of Patent: March 17, 1981
    Assignee: Norma J. Webb
    Inventors: Norman J. Webb, David Bories
  • Patent number: 4250500
    Abstract: In a smoke detector of the type wherein an alarm signal is generated to activate an audible indicator and an oscillator circuit drives a pulsating visual indication of standby readiness, the oscillation frequency increases between its standby and alarm modes. In addition, duty cycle means controls the operative period of the alarm indicator during each cycle of the increased frequency. The smoke detector includes a relaxation oscillator where the oscillation frequency is proportional to the charge rate of a capacitor. Independent current sources are connected through separate switches to change the charge rate of the capacitor and thus the oscillation frequency. Each switch is controlled by signals from a separate detector of a condition which requires that the oscillation frequency be changed, for example, the presence of smoke.
    Type: Grant
    Filed: October 22, 1979
    Date of Patent: February 10, 1981
    Assignee: RCA Corporation
    Inventor: Otto H. Schade, Jr.
  • Patent number: 4247299
    Abstract: An air pollutant and/or fire combustion sensing apparatus includes a sensing electrode having an electrically non-conductive or dielectric sensing layer which has a surface resistivity in excess of 1.times.10.sup.10 ohms/square (and preferably 1.times.10.sup.15), and a bulk resistivity in excess of 1.times.10.sup.12 ohm-cm, and preferably 1.times.10.sup.15 at 50% R.H., and which is essentially free of dipole-hydrogen bonding forces such that the surface energy component is primarily due to dispersion bonding forces and, if at all, only incidentally as a result of dipole-hydrogen bonding forces. The latter appears to be a principal factor and desirably has a value of less than 5.0 ergs/cm.sup.2 and preferably less than 1.0 erg/cm.sup.2. The gases detected have a large Van der Waal gas "a" constant and dipole moment. This sensing layer adsorbs air borne polar constituents to alter the charge on the electrode.
    Type: Grant
    Filed: June 19, 1978
    Date of Patent: January 27, 1981
    Assignee: Johnson Controls, Inc.
    Inventors: Carl F. Klein, Paul E. Thoma
  • Patent number: 4246572
    Abstract: A battery-powered fire alarm including a smoke detector circuit, a controllable horn circuit and a battery monitoring circuit. The smoke detector employs a pair of complementary field-effect transistor switches with gates respectively connected to an ionization chamber and a potentiometer of a Wheatstone bridge circuit connected across the battery. The field-effect transistors are biased off to minimize standby power consumption and are connected such that the threshold voltages thereof are offsetting to minimize supply voltage sensitivity of the detector. When the voltage from the ionization chamber assumes a value approximately equal to a preselected alarm voltage at the potentiometer, both field-effect transistors turn on to energize an alarm circuit to sound an alarm. Hysteresis circuitry is provided to ensure that the complementary switches, once turned on, will not turn off and thereby terminate the alarm until after the alarm condition has terminated.
    Type: Grant
    Filed: March 27, 1978
    Date of Patent: January 20, 1981
    Assignee: Patent Development & Management Company
    Inventor: Larry D. Larsen
  • Patent number: 4243981
    Abstract: An ionization fire-signal device is provided which is compact in construction so that it has a small axial height. The housing for the device includes an axial extending outer wall and a transversely extending front wall to form a cup shaped housing. An insulator, including an axially extending circular wall which forms an enclosure, is positioned inside the housing and cooperates with the housing to form a measuring chamber. The axial dimension of the circular insulator wall and outer housing wall are approximately equal. In addition, a reference chamber is formed between the circular wall of the insulator and the outer wall of the housing such that the reference chamber is arranged transversely adjacent to the measuring chamber. A radiation source for ionizing the measuring chamber and reference chamber is also provided.
    Type: Grant
    Filed: November 17, 1978
    Date of Patent: January 6, 1981
    Inventor: Hartwig Beyersdorf
  • Patent number: 4238788
    Abstract: An ionization type smoke detector includes an element for giving a visible indication of operativeness of the system together with a component responsive thereto for representing impending failure of the power source. A housing for the system includes a battery-containing well that includes a channel permitting finger-access to the batteries. A pushbutton is located in a wall of the housing. An electrically-conductive probe is positioned within an ionization chamber and is associated with the pushbutton for addressing the probe in a manner that creates a simulation of the existence of combustion. In response to a signal from the ionization chamber, digital processing is employed in order to enable alarm indication as appropriate as well as to monitor continued capability of the battery power source. Special circuitry cooperates advantageously with those features as well as in interrelating the different features so as to minimize complexity.
    Type: Grant
    Filed: January 3, 1978
    Date of Patent: December 9, 1980
    Assignee: Teledyne Industries, Inc.
    Inventors: Robert J. Rosauer, James F. Gamble, Jr.
  • Patent number: 4238677
    Abstract: An alarm device for detecting smoke, fire or the like includes a reference and measurement chamber for comparing the character of the ambient atmosphere with a volume of reference gas, and a radioactive source for ionizing the contents of each of the chambers. Electrodes communicating with each of the chambers measures an electric field within each of the latter indicative of the degree of ionization of the contents thereof. An electronic circuit senses the relative difference of the signals produced by the electrodes associated with each of the chambers and activates an alarm when a signal of predetermined magnitude is sensed indicating the presence of smoke or the like in the area of the detector.
    Type: Grant
    Filed: March 31, 1978
    Date of Patent: December 9, 1980
    Assignee: Societe Gamma-Electronic
    Inventor: Emile L. Hugon
  • Patent number: 4234877
    Abstract: In an ion type smoke sensor including a smoke sensor having an internal electrode, an intermediate electrode and an external electrode, and a field effect transistor having a control input terminal connected to the intermediate electrode, a first output terminal connected to the internal electrode and a second output terminal connected to the external electrode, an ion type smoke sensor of this invention comprises an oscillator circuit for generating an oscillating output having a predetermined oscillating frequency; a reference level source for intermittently producing an output signal with a predetermined reference level in response to the oscillating output from the oscillator circuit; and a comparing circuit for comparing a sensing output between the first and second output terminals of the field effect transistor with the reference level from the reference level source to produce a fire sensing signal in accordance with the result of the comparison.
    Type: Grant
    Filed: August 23, 1979
    Date of Patent: November 18, 1980
    Assignee: Hochiki Corporation
    Inventors: Masaki Maruyama, Kohei Nakamura
  • Patent number: 4225860
    Abstract: An improved fire detector has both ionization chamber and photoelectric type products of combustion sensing devices, both of which must detect combustion for an alarm to be generated. The sensing devices are each adjusted to a quiescent sensitivity, but upon combustion being detected by one of the devices the sensitivity of the other device is automatically increased. In this manner, the detector operates very reliably to generate an alarm in the very early stages of a fire irrespective of whether the combustion process generates primarily visible or generally invisible type products of combustion, yet spurious generation of false alarm is minimized.
    Type: Grant
    Filed: January 15, 1979
    Date of Patent: September 30, 1980
    Assignee: Pittway Corporation
    Inventor: Frederick J. Conforti
  • Patent number: 4224611
    Abstract: A fire alarm system comprises a central control station feeding through a plurality of parallel supply lines a direct current voltage to a corresponding plurality of remote alarm stations. Each station has a fire sensor including a reference ionization chamber and a measuring ionization chamber, both chambers being connected in series between the two supply lines and having a common intermediate electrode. A field effect transistor has a gate electrode connected to the intermediate electrode of the ionization chambers and a source drain conducting channel the conductivity of which is controlled by the gate electrode. The input resistance and the input capacitance of the field effect transistor is connected parallel to the reference ionization chamber and defines therewith a first relatively short time constant of about two seconds.
    Type: Grant
    Filed: March 24, 1978
    Date of Patent: September 23, 1980
    Inventor: Wolfgang Munstedt
  • Patent number: 4223305
    Abstract: The present invention is a single station type ionization smoke sensor which operates on a dc battery having a voltage lower than the voltage of about 9 volts usually needed for operation of ionization-type smoke sensors. The smoke sensor of the present invention includes a voltage booster means for boosting the battery voltage, a voltage detector means which detects when the boosted voltage falls below a predetermined value and an alarm energization means which energizes an alarm when an ionization type smoke detector means detects combustion products or when the voltage detector means detects a drop in the boosted voltage below the predetermined voltage.
    Type: Grant
    Filed: August 17, 1978
    Date of Patent: September 16, 1980
    Assignee: Hochiki Corporation
    Inventor: Takeo Arima
  • Patent number: 4222046
    Abstract: An ionizing type smoke detector device has an output voltage which is compared with a reference voltage and upon the output dropping below the reference, a horn is energized. The reference voltage is normally quite low to reduce the number of false alarms and thus the smoke detector is relatively insensitive to smoldering fires which may require a high sensitivity of the smoke detector device. A timer means periodically modifies the reference voltage to a high value for a short period of time to make the smoke detector more responsive to smoldering fires and yet with the higher sensitivity for the short period of time the number of false alarms are kept at a minimum. Additionally a counter circuit is provided for counting the outputs of the smoke detector over three timing periods and if an output exists for three consecutive periods, an output to the horn is provided.
    Type: Grant
    Filed: July 31, 1978
    Date of Patent: September 9, 1980
    Assignee: Honeywell Inc.
    Inventors: B. Hubert Pinckaers, Stephen A. Haglund
  • Patent number: 4213046
    Abstract: An ionization fire-signal device with an ionized measuring chamber, a reference element connected in series with the reference chamber, an amplifier stage controlled by the electric potential of the connection point of the measuring chamber and the reference element and comprising a field effect transistor, and a signal circuit controlled by the amplifier stage and comprising another transistor. A bistable behavior of the ionization fire-signal device is achieved by a positive signal feedback from the signal circuit to the substrate of the field effect transistor.
    Type: Grant
    Filed: February 17, 1978
    Date of Patent: July 15, 1980
    Inventor: Hartwig Beyersdorf
  • Patent number: 4213047
    Abstract: A smoke detector of superior smoke sensitivity characterized by a compact unipolar ionization chamber in which the ionization area or zone is situated and defined between the source of alpha particles and an electrode which confronts the source; another electrode, which attracts the unipolar charge carriers, is situated on an indirect path from the source, preferably being behind such source with respect to the pattern of radiation emitted therefrom.
    Type: Grant
    Filed: October 25, 1978
    Date of Patent: July 15, 1980
    Assignee: General Signal Corporation
    Inventor: Herbert W. McCord
  • Patent number: 4205306
    Abstract: Improvements in battery operated smoke detector electronics including micro power astable multi-vibrator circuitry which has fast reliable switching of the inverters and electronic circuitry for single or dual ionization chamber smoke detector which maintains constant smoke detector sensitivity throughout the usable life of the battery.
    Type: Grant
    Filed: January 9, 1978
    Date of Patent: May 27, 1980
    Assignee: Dicon Systems Limited
    Inventor: Zbigniew W. Turlej
  • Patent number: 4196426
    Abstract: A self-monitoring ion chamber type combustion products detection apparatus operable to generate perceptibly different output signals indicative of, respectively: the apparatus is being tested; the condition of the apparatus is normal; an alarm condition is detected; an apparatus malfunction is detected; and, a low power supply voltage is detected. The impedance of the ion chamber of the apparatus varies as a function of the degree of combustion products in the atmosphere being monitored and this change in impedance produces a variation in the output voltage of the ion chamber which is used by the apparatus to produce an alarm signal. In generating different output signals, the apparatus employs test, alarm, fault and low power supply reference voltages. An oscillator circuit is selectively driven by one or more substantially constant current sources to produce output pulses having predetermined frequencies which are utilized in producing at least some of the perceptibly different output signals.
    Type: Grant
    Filed: July 10, 1978
    Date of Patent: April 1, 1980
    Assignee: Emerson Electric Company
    Inventor: Francis T. Ogawa
  • Patent number: 4194192
    Abstract: Alarm devices are provided with circuit means for permitting interconnection of the alarm devices into an alarm system in which each of the alarm devices continually senses for an adverse condition, such as smoke in a smoke detection alarm system, and in which all of the alarm devices signal an alarm in response to the sensing of an adverse condition. The interconnections for the alarm devices are such that the alarm devices not directly coupled to operative sources of electric power will, nevertheless, sense adverse conditions and signal alarms when any one of the alarm devices senses an adverse condition.
    Type: Grant
    Filed: December 11, 1978
    Date of Patent: March 18, 1980
    Assignee: General Electric Company
    Inventor: Harry Albinger, Jr.
  • Patent number: 4194191
    Abstract: A smoke detector of the ionization type is provided with a movable test target or probe for intercepting alpha radiation within the measuring chamber when moved to a particular position. As a result of the interception of alpha particles, the electrical resistance of the chamber between a pair of electrodes is increased. Since the electrical resistance similarly increases when airborne products of combustion enter the measuring chamber, the operative position and size of the test target may be selected such that its movement to its operative position results in electrical simulation of a predetermined level of airborne products of combustion within the measuring chamber.
    Type: Grant
    Filed: February 1, 1978
    Date of Patent: March 18, 1980
    Assignee: General Electric Company
    Inventor: Robert J. Salem
  • Patent number: 4189644
    Abstract: An ionization chamber of the type used in an ionization smoke detector is made adjustable. The chamber has two electrodes and one radioactive source for ionizing the electrode gap. One of the electrodes is laterally displaceable relative to the other. As a result of displacement of this electrode, areas of the electrode with differing geometrical configurations can be brought into the ionization zone of the radioactive source.Several different embodiments of the electrode with different geometrical configurations are described.
    Type: Grant
    Filed: November 23, 1977
    Date of Patent: February 19, 1980
    Assignee: Cerberus AG
    Inventors: Wolfgang Schubert, Bernhard Durrer
  • Patent number: 4183020
    Abstract: A field effect transistor in common-drain amplifier connection is followed in direct-coupled cascade by a bipolar transistor of similar conductivity type, in common-emitter amplifier connection, and without emitter degeneration resistance for limiting its collector current by means of current feedback. Rather the collector current is limited by (a) restricting the range of source voltage variation of the field effect transistor by a threshold conducting means between the source electrode of the field effect transistor and the emitter electrode of the bipolar transistor and (b) inserting a resistance between the source electrode of the field effect transistor and the base electrode of the bipolar transistor to limit the maximum base drive current available to the bipolar transistor when the restricted source voltage of the field effect transistor departs most from the emitter voltage of the bipolar transistor.
    Type: Grant
    Filed: September 8, 1978
    Date of Patent: January 8, 1980
    Assignee: RCA Corporation
    Inventor: Otto H. Schade, Jr.
  • Patent number: 4176311
    Abstract: Smoke is detected by a surface ionization effect on a heated wire filament disposed opposite a negative ion collector electrode. Current flow between the wire and the electrode increases in the presence of smoke. The increase is probably attributable to surface ionization of smoke particles on the heated wire.
    Type: Grant
    Filed: December 23, 1976
    Date of Patent: November 27, 1979
    Assignee: General Electric Company
    Inventor: William D. Davis
  • Patent number: 4168497
    Abstract: At least two sensors are used, providing electrical output signals to indicate alarm conditions, one of the sensors being a bipolar ion sensor having a shielded ion chamber formed to slow or brake atmospheric currents therethrough, and a second sensor which operates essentially in unipolar mode having an ion chamber freely accessible to atmospheric flow therethrough.
    Type: Grant
    Filed: January 19, 1978
    Date of Patent: September 18, 1979
    Assignee: Cerberus AG
    Inventor: Andreas Scheidweiler
  • Patent number: 4167687
    Abstract: A smoke detection apparatus is disclosed having a highly efficient ionization chamber. The ionization chamber is primarily formed by a wire mesh collector that readily admits products of combustion such as smoke into the chamber which has therein an alpha emitting, radioactive source and a selectable portion of a tuning screw. Two types of smoke detectors are shown utilizing the ionization chamber with one of the detectors operating from a conventional A.C. power source and the other being battery operated. The smoke detector utilizing the conventional A.C. power source requires no transformer and has the alarm indicating horn connected with the A.C. source with the horn being triggered by a silicon controlled rectifier connected with the radioactive source in the ionization chamber through a field effect transistor switch. A rectified and regulated D.C. voltage is provided to the wire mesh collector and to the field effect transistor switch.
    Type: Grant
    Filed: February 10, 1977
    Date of Patent: September 11, 1979
    Assignee: Unitec, Inc.
    Inventor: Douglas E. Furney
  • Patent number: 4163226
    Abstract: Alarm condition detecting apparatus in the form of a combustion products detection system for monitoring a zone to detect the occurrence of fire therein. The apparatus has a plurality of detecting units adapted to be interconnected as parallel loads with a control unit. Each detecting unit receives operating power which may be from the control unit and functions to monitor a selected portion of the zone, generating, as appropriate, condition signals indicative of condition normal, impending alarm, alarm or unit malfunction. The impending alarm and unit malfunction signals are preferably pulsed signals of distinctly different frequencies and a light emitting diode (LED) arrangement is included in the detecting units to generate visual ouputs corresponding to the impending alarm, alarm and unit malfunction signals.
    Type: Grant
    Filed: September 2, 1977
    Date of Patent: July 31, 1979
    Assignee: Statitrol Division Emerson Electric Co.
    Inventor: Francis T. Ogawa
  • Patent number: 4155081
    Abstract: A circuit for a rechargeable battery backup power source used with an ionization smoke detector device whereby upon the failure of the main alternating current power source, a battery which is normally charged from the power source during standby operation is connected to an ionization smoke detector circuit to maintain its energization upon the loss of the alternating current power source.
    Type: Grant
    Filed: October 25, 1977
    Date of Patent: May 15, 1979
    Assignee: Honeywell Inc.
    Inventor: Stephen A. Haglund
  • Patent number: 4150373
    Abstract: An ionization particle detector for indicating the presence of charged particles in a gas includes a single ionization chamber having two defined regions of electrical field intensity. The first region is of small geometric volume and high electric field intensity while the second region is of large geometric volume and low electric field intensity. The radioactive source for generating the ions is located near one electrode while the second electrode forming the walls of the chamber are located such that the walls are incident near the Bragg ionization peak of the detector. A probe is positioned between the two regions for detecting the maximum electric field change when particles enter the chamber.
    Type: Grant
    Filed: January 27, 1977
    Date of Patent: April 17, 1979
    Inventor: Louis Ried, Jr.
  • Patent number: 4139770
    Abstract: In the disclosed ionization fire alarm structure, a gap that admits ambient air to the alarm test chamber eliminates directional smoke sensitivity or any insensitivity that might be caused by high air velocities. A ring shaped wall section in the approximate plane of the center electrode and common to the test and reference chambers, and an axially extending tubular wall and housing that enclose the jacket of a flat-bottomed external electrode establish the gap that admits ambient air to the test chamber and form axially compact device with adequate electrical insulation. An insulator cover and angular bends which are formed in the latch springs that couple the alarm to the base prevent unauthorized disassembly by requiring a special manipulation to uncouple these components.
    Type: Grant
    Filed: November 21, 1977
    Date of Patent: February 13, 1979
    Inventor: Hartwig Beyersdorf
  • Patent number: 4139846
    Abstract: Apparatus for supervising the energy level of a battery is characterized by circuitry for periodically loading the battery, monitoring the change in voltage across the battery from the condition prior to loading to during loading, and generating a signal whenever the change in voltage is at least equal to a predetermined magnitude. In one embodiment the apparatus is used with a fire detector powered by the battery, and the signal operates an alarm to indicate impending battery failure.
    Type: Grant
    Filed: June 30, 1977
    Date of Patent: February 13, 1979
    Assignee: Pittway Corporation
    Inventor: Frederick J. Conforti
  • Patent number: 4138670
    Abstract: An improved a.c. voltage powered warning device for detecting the occurrence of predetermined phenomena, is characterized by battery backup for providing power to the device in the event of interruption of the a.c. voltage. In the disclosed embodiments the warning device is a fire detector having circuitry for supervising the energy level of the backup battery and for providing a warning upon the energy level decreasing to a predetermined value, and for testing a combustion detecting and alarm generating portion of the detector.
    Type: Grant
    Filed: January 3, 1977
    Date of Patent: February 6, 1979
    Assignee: Pittway Corporation
    Inventors: Quentin L. Schneider, Richard J. Schwarzbach
  • Patent number: 4138664
    Abstract: An improved warning device having a sensor responsive to predetermined phenomena to generate a signal which changes in value upon the presence of the phenomena, and means for comparing the signal with a reference potential and for generating an indication upon a predetermined difference therebetween, is characterized by integrated circuit components which may economically be manufactured and assembled, and which maintain substantially constant the sensitivity of the device to the phenomena despite changes in the level of power supplied thereto. Where the warning device is a battery powered fire detector, the phenomena to be sensed is products of combustion, circuitry supervises the power level of the battery, and means are provided for readily testing the entire combustion detecting and indication generating portion of the detector, whereby a user of the detector may be assured of proper operation of the detector in response to combustion.
    Type: Grant
    Filed: December 14, 1976
    Date of Patent: February 6, 1979
    Assignee: Pittway Corporation
    Inventors: Frederick J. Conforti, Richard J. Schwarzbach, Quentin L. Schneider
  • Patent number: 4134111
    Abstract: Method and apparatus for detecting an aerosol, such as smoke, is provided. An electric potential is applied to one of a pair of electrically isolated conductors spaced apart from one another by a gap into which smoke may permeate. No potential is applied to the other conductor to attract charge particles to it. The two conductors define a tapering channel for guiding smoke particles to the gap between the conductors. The potential is high enough to ionize any aerosol particles in the gap. These ionized particles then drift to the second conductor, altering its potential. A high-gain amplifier detects any change in the potential of the second conductor and provides an output to indicate detection of an aerosol.
    Type: Grant
    Filed: December 16, 1976
    Date of Patent: January 9, 1979
    Assignee: N.V. Tools Limited
    Inventor: Derrick A. Nudds
  • Patent number: RE29983
    Abstract: Time pulse generator having biasing means therefor including a control device, which may be a transistor and means interconnecting the biasing means to the battery being monitored. The output of the time pulse generator is utilized to drive a signaling device to indicate a low level of battery energy and/or an alarm condition as detected by an external condition sensor.
    Type: Grant
    Filed: June 21, 1976
    Date of Patent: May 1, 1979
    Assignee: Emerson Electric Co.
    Inventors: Lyman L. Blackwell, Paul A. Staby
  • Patent number: RE30117
    Abstract: To render an ionization-type sensing element essentially immune to changes in ambient conditions, principally temperature or operating voltage, while still using low-current draining circuits to sense response of the ionization chamber of the sensor, the threshold response level of a field effect transistor (FET) is arranged to have approximately the same temperature response characteristic, within the range of ambient temperature considered, as the ionization cell so that the overall circuit or system combination of the cell and FET amplifier will have a response which is essentially independent of ambient temperature or similar conditions. The source path of the FET is connected to a voltage divider which is so dimensioned that the voltage division ratio (R.sub.2 /R.sub.1) is related to the temperature coefficient (.alpha.) of the base-emitter voltage of the FET and the temperature coefficient (.beta.) of the measuring ionization cell chamber:R.sub.2 /R.sub.1 =(.beta./.alpha.)-1.
    Type: Grant
    Filed: February 13, 1978
    Date of Patent: October 16, 1979
    Assignee: Cerberus AG
    Inventors: Andreas Scheidweiler, Otto Meier
  • Patent number: RE30323
    Abstract: A smoke detector is disclosed which comprises an inner electrode, an intermediate electrode with a hole for passing radioactive rays therethrough, an outer electrode having openings for allowing smoke to flow therethrough, and one radioactive source, the inner and intermediate electrodes forming an inner ionization chamber, the intermediate and outer electrodes forming an outer ionization chamber, the radioactive source being disposed in the inner ionization chamber. A proper quantity of radioactive rays from the radioactive source is applied into the outer ionization chamber through the hole provided in the intermediate electrode.
    Type: Grant
    Filed: September 5, 1978
    Date of Patent: July 1, 1980
    Assignee: Hochiki Kabushiki Kaisha
    Inventor: Yukio Tomioka
  • Patent number: RE30620
    Abstract: A high output smoke and heat detector alarm system comprises a high output audible alarm means which includes a piezoelectric transducer and a voltage doubling means in combination with an improved smoke and heat detector which includes a low voltage power supply source, an ambient temperature detecting means, at least one ionization sensing chamber, a voltage amplitude comparing means, and a low voltage sensing means.
    Type: Grant
    Filed: July 3, 1978
    Date of Patent: May 19, 1981
    Assignee: P. R. Mallory & Co. Inc.
    Inventors: Louis P. Sweany, Michael T. Burk