ALARM DEVICE GAS DISCHARGE TUBE

• US 3,621,262 A
• Filed: 02/07/1969
• Issued: 11/16/1971
• Est. Priority Date: 02/15/1968
• Status: Expired due to Term

• Current Assignee: Daniel Lecuyer
• Original Assignee: Daniel Lecuyer
• Inventors: Lecuyer, Daniel
• Primary Examiner(s): James W. Lawrence
• Assistant Examiner(s): Martin Abramson
• Application Number:
  US04/797,402
• Time in Patent Office: 1,012 Days
• Field of Search: 250/206,214 357/311 340/228
• US Class Current: 250/214.00R
• CPC Class Codes: G01T 7/125 Alarm- or controlling circuits using ionisation chambers, proportional counters or Geiger-Mueller tubes, also functioning as UV detectors measuring radiation intensity with counting tubes G01T1/18; measuring radiation intensity with ionisation chambers G01T1/185; flame monitoring in combustion devices F23Q7/00, F23N; fire alarms actuated by presence of radiation of particles, e.g. of infrared radiation, of ions G08B17/11; discharge tubes per se H01J47/00
• CPC Class Codes: G08B 17/12 Actuation by presence of radiation or particles, e.g. of infrared radiation or of ions

Abstract

Alarm device for detecting a radiation in a given space. The device comprises a discharge tube responsive to said radiation, a pulse generator having a first frequency and connected to said tube, a counting device whose input is connected in the circuit of said tube and of said generator, a time-base circuit connected to the reset terminal of said counting device and furnishing reset pulses at a second frequence, a control device connected to said counting device, and a signal device controlled by said control device.

Claims

1. An alarm device for detecting a radiation in a given space and producing an alarm signal when the quantity of energy particles of said radiation per time unit exceeds a predetermined value, said device comprising in combination, a discharge tube responsive to said radiation and connected so as to be conductive each time energy particLes of said radiation impinges thereon, a pulse generator having a first frequency at a voltage sufficient to cause conduction of said tube by combined action of said voltage and said energy particles, a circuit connecting said generator to said tube, a counting device having a reset terminal and an input, said input being connected in said circuit, so as to be rendered operative each time said tube is conductive, a time-base circuit connected to said reset terminal and furnishing reset pulses at a second frequency, a control device connected to said counting device, and a signal device controlled by said control device.

2. A device as claimed in claim 1, wherein said counting device is a binary counter comprising a series of flip-flops.

3. A device as claimed in claim 2, said control device having an AND gate, equivalent outputs of said flip-flops being connected to said AND gate, the alarm device further comprising a thyristor whose control electrode is connected to the output of said gate, said thyristor being connected in parallel with a relay coil and in series with a signal device.

4. A device as claimed in claim 2, wherein said time-base circuit is a multivibrator whose output is connected to reset inputs of said flip-flops.

5. A device as claimed in claim 3, wherein the control electrode of said thyristor is directly connected to an output of the last flip-flop of said counting device.

6. A supervising installation comprising a plurality of alarm devices for detecting a radiation in a given space and producing an alarm signal when the quantity of energy particles of said radiation per time unit exceeds a predetermined value, each alarm device comprising in combination a discharge tube responsive to said radiation and connected so as to be conductive each time energy particles of said radiation impinges thereon, a pulse generator having a first frequency at a voltage sufficient to cause conduction of said tube by combined action of said voltage and said energy particles, a circuit connecting said generator to said tube, a counting device having a reset terminal and an input, said input being connected in said circuit so as to be rendered operative each time said tube is conductive, a time-base circuit connected to said reset terminal and furnishing reset pulses at a second frequency, a control device connected to said counting device, and a signal device controlled by said control device, said alarm devices constituting separate supervising stations in spaced relation, said pulse generator being common to said alarm devices and located in a central supervising station, each alarm device comprising a switch controlled by the corresponding control device, said installation further comprising a supply circuit which is connected to said pulse generator and includes a resistor in series, said switches being connected in series with said resistor, and a central alarm control circuit responsive to the variation in the potential of one of the points of connection of said supply circuit.

7. An installation as claimed in claim 6, wherein said pulse generator comprises a transformer, a rectifier bridge and a system of a plurality of Zener diodes connected in parallel with output terminals of said rectifier bridge.

8. An installation as claimed in claim 6, wherein said central control circuit comprises a system including two field-effect transistors having drain-source circuits connected in parallel, a coil of a relay with sequence action being connected in series with said system, one of said field-effect transistors having a grid connected to said point of connection of said supply circuit whereas the grid of the other of said field-effect transistors is connected to said point through a Zener diode.

9. An installation as claimed in claim 7, wherein said point of connection of said supply circuit is the negative terminal of said rectifier bridge.