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    Improvements in or relating to supervisory systems
    54.
    发明专利
    Improvements in or relating to supervisory systems 未知

    公开(公告)号：GB1079528A

    公开(公告)日：1967-08-16

    申请号：GB4290764

    申请日：1964-10-21

    Applicant: ELECTRONICS CORP AMERICA

    IPC: F23N5/08

    Abstract: 1,079,528. Photo-electric flame detector. ELECTRONICS CORPORATION OF AMERICA. Oct.21, 1964 [Nov. 5, 1963], No.42907/64. Heading G1A. In a fail-safe detector flame failure is periodically simulated by a chopper 14 in the flame radiation beam, the resulting appearance and disappearance of the flame causing a capacitor 90 to be repeatedly charged and discharged but maintained at a potential high enough to hold a control relay 96 actuated, which is released only when a complete failure of the flame prevents the capacitor 90 from recharging. Signals from the lead sulphide detector 12 after passing through a filter amplifier tuned to the flicker frequency of the flame, charge capacitor 52 to cause triode stage 62 to conduct, which by charging capacitor 74 shuts off triode stage 64. The voltage across the anode resistor 78 is now removed and allows capacitor 84 to recharge the relay capacitor 90. Upon removal of the flame radiation by the chopper, triode stage 62 ceases to conduct and triode stage 64 conducts; the voltage across anode resistor 78 is restored so isolating relay capacitor 90 by diode 88 and recharging capacitor 84. If complete flame failure occurs triode 64 is held conducting so the charge on the relay capacitor 90 is not regularly replenished and the relay contacts 90 open to operate a fuel valve 98. Any component failure has a similar effect. In another embodiment not using the flame flicker frequency Fig. 2 (not shown) an avalanche type of detector is fed from an A.C. supply. The pulses are produced as the detector repeatedly breaks down when irradiated are fed through a frequency selective network to operate an S.C.R. to maintain a transistor in a non-conducting condition. A capacitor similar in function to 84 is charged and discharged as the transistor conducts and is shut off in correspondence with the absence simulator.

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