Flame ionization detector status indicator
AssigneeThe Perkin-Elmer Corporation
InventorEdward B. Delany
Life of this patent
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Abstract
Thermocouples are disposed in the flame exhaust passage and exteriorly on the housing of each ionization detector to monitor the flame status thereof within an environment of widely varying temperature. A temperature differential signal is derived from the thermocouples of each ionization detector, with each temperature differential signal being compared to a common threshold level at which an indication of a flameout condition occurs. The indication of a flameout condition in each ionization detector is varied relative to the temperature differential thereof through a variable gain amplification stage. Switches are disposed for individually interrupting each temperature differential signal and flameout conditions occurring in any one or more of the ionization detectors are identifiable therewith.
Claims11
Flame monitoring apparatus for at least one ionization detector within an environment of widely varying temperature, comprising:
- a thermocouple disposed in the flame exhaust passage of each ionization detector;
- a thermocouple disposed on the housing of each ionization detector;
- a differential amplifier for the outputs from said thermocouples of each ionization detector, each said differential amplifier having the inputs thereof separately connected to the thermocouple outputs;
- and
- means for indicating when the output from any one of said differential amplifiers transgresses a threshold level.
Flame monitoring apparatus for a pair of ionization detectors within an environment of widely varying temperature, comprising:
- a pair of first thermocouples, said first thermocouples being individually disposed in the flame exhaust passage of one ionization detector;
- a pair of second thermocouples, said second thermocouples being individually disposed on the housing of one ionization detector;
- a pair of differential amplifiers, each said differential amplifier having the inputs thereof connected separately to the outputs from said first and second thermocouples of one ionization detector;
- a pair of comparators, each said comparator having the inputs thereof connected separately to a first voltage terminal and to the output of one said differential amplifier;
- a transistor having the base thereof commonly connected to both outputs from said comparators;
- a pair of diodes, said diodes being individually connected to reverse bias the base of said transistor relative to said first voltage terminal and relative to a second voltage terminal, said second voltage terminal being also connected to the emitter of said transistor;
- switching means disposed between the base of said transistor and each output from said comparators for independently interrupting current flow therebetween;
- and
- an indicator connected to the collector of said transistor, said first voltage terminal being also connected to said indicator with a voltage from between said first and second voltage terminals being applied across said indicator by said transistor after the output from either of said differential amplifiers reaches the voltage level of said first voltage terminal and thereafter, the flame status of each ionization detector being determinable through said switching means.
Dependencies are inferred from the claim text.