US4904986A
Expired / Lapsed
US
⏱️ 0.0 years remaining
IR flame amplifier
Assignee: Honeywell Inc
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Filing: 1989-01-04
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Granted: 1990-02-27
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Expires: 2009-01-04
Abstract
Abstract A flame detector, for use with a photocell which produces a flame signal when the photocell is exposed to a flame, is used for detecting the presence of a flame. An input circuit is coupled to the photocell for receiving and buffering the flame signal. The buffered flame signal is filtered and amplified in a filter. An output circuit further amplifies the filtered flame signal providing an output flame signal. A switch is also used in the flame detector for substantially short circuiting the flame signal to a known value upon receiving a switch-close signal from either a test computer or from a hot refractory detection circuit. A flame-out condition is detected by the hot refractory detection circuit which generates an HRD signal causing the flame signal to be substantially short circuited to a known value thereby eliminating a false flame signal caused by hot refractory shimmering.
Inventors
- 👤 B. Hubert Pinckaers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:58
CPC Classifications
F; F23; F23N; F23N5/00; F23N5/02; F23N5/08; F23N5/082; F23N1/00; F23N2227/00; F23N2227/12; F23N2227/16; F23N2227/18; F23N2229/00; F23N5/24
Claims Analysis
Total Claims: 60
Claim 1
Independent Claim
195 words
A flame detector for use with flame detection means for detecting the presence of a flame and producing a flame signal which includes an AC component and a DC component when the flame is detected and for producing a no-flame signal when no flame is detected, the flame detector comprising: input means, coupled to the flame detection means, for receiving and buffering the AC component of the flame signal thereby providing an AC buffered flame signal; filter means, coupled to the input means, for filtering the AC buffered flame signal thereby providing an AC filtered flame signal; output means, coupled to the filter means, for amplifying the AC filtered flame signal and for providing a flame output signal; shorting means, coupled to the input means, for substantially, selectively short circuiting the AC component of the flame signal to a known voltage level; and hot refractory detection means, coupled to the flame detection means, for detecting the no-flame signal and for generating an HRD signal causing the AC component of the flame signal to be substantially short circuited to a known voltage level, thereby substantially eliminating a false flame output signal caused by hot refractory shimmering.
Claim 2
Dependent Claim
195 words
A flame detector for use with flame detection means for detecting the presence of a flame and producing a flame signal which includes an AC component and a DC component when the flame is detected and for producing a no-flame signal when no flame is detected, the flame detector comprising: input means, coupled to the flame detection means, for receiving and buffering the AC component of the flame signal thereby providing an AC buffered flame signal; filter means, coupled to the input means, for filtering the AC buffered flame signal thereby providing an AC filtered flame signal; output means, coupled to the filter means, for amplifying the AC filtered flame signal and for providing a flame output signal; shorting means, coupled to the input means, for substantially, selectively short circuiting the AC component of the flame signal to a known voltage level; and hot refractory detection means, coupled to the flame detection means, for detecting the no-flame signal and for generating an HRD signal causing the AC component of the flame signal to be substantially short circuited to a known voltage level, thereby substantially eliminating a false flame output signal caused by hot refractory shimmering.
Claim 3
Dependent Claim
32 words
The flame detector of claim 1 wherein the DC component reaches a flame-on level which represents the presence of the flame and a flame-out level which represents the absence of the flame.
Claim 4
Dependent Claim
38 words
The flame detector of claim 1 wherein the AC component represents flame flicker when the flame is present and has a flicker frequency, and wherein the AC component is coupled to the input means by AC coupling means.
Claim 5
Dependent Claim
41 words
The flame detector of claim 3 wherein the input means further comprises: limiting means, AC coupled to the flame detection means by the coupling means, for limiting the AC component to a predetermined level to prevent damage to the flame detector.
Claim 6
Dependent Claim
101 words
The flame detector of claim 4 wherein the limiting means further comprises: a first diode with its input coupled to the AC coupling means and its output coupled to a bias voltage where the first diode is reverse biased and where the first diode begins to conduct when the AC component rises above a predetermined level; and a second diode with its input coupled to a bias voltage and its output coupled to the AC coupling means where the second diode is reverse biased and where the second diode begins to conduct when the AC component drops below a predetermined level.
Claim 7
Dependent Claim
18 words
The flame detector of claim 5 wherein the first and second diodes are contained on a monolithic chip.
Claim 8
Dependent Claim
18 words
The flame detector of claim 6 wherein leakage currents of the first and second diodes are substantially equal.
Claim 9
Dependent Claim
24 words
The flame detector of claim 4 wherein the input means further comprises: input filter means for bypassing noise in the AC component to ground.
Claim 10
Dependent Claim
48 words
The flame detector of claim 8 wherein the input means further comprises: load resistance means, coupled to the input filter means, for loading the AC component, where the AC component appears across the load resistance means, and where substantially no DC voltage appears across the load resistance means.
Claim 11
Dependent Claim
66 words
The flame detector of claim 9 wherein the shorting means further comprises: a control input for receiving the switch-close signal; a first switch terminal coupled to the load resistance means; and a second switch terminal, coupled to a known voltage, wherein the shorting means substantially short circuits the first switch terminal to the second switch terminal when the switch-close signal is applied to the control input.
Claim 12
Dependent Claim
16 words
The flame detector of claim 10 wherein the shorting means comprises: an analog, bilateral, solid-state switch.
Claim 13
Dependent Claim
33 words
The flame detector of claim 9 wherein the input means further comprises: buffer means, coupled to the load resistance means, for buffering the AC component and thereby providing the AC buffered flame signal.
Claim 14
Dependent Claim
14 words
The flame detector of claim 12 wherein the buffer means includes an operational amplifier.
Claim 15
Dependent Claim
23 words
The flame detector of claim 3 wherein the filter means further comprises: a multiple feedback, bandpass filter with a first and second stage.
Claim 16
Dependent Claim
19 words
The flame detector of claim 14 wherein the first and second stages are stagger-tuned to pass the flicker frequency.
Claim 17
Dependent Claim
16 words
The flame detector of claim 15 wherein the filter means amplifies the AC buffered flame signal.
Claim 18
Dependent Claim
33 words
The flame detector of claim 3 wherein the shorting means further comprises a switch which short circuits the AC component of the flame signal to the known voltage upon receiving a switch-close signal.
Claim 19
Dependent Claim
16 words
The flame detector of claim 17 wherein the switch-close signal is generated by a test pulse.
Claim 20
Dependent Claim
16 words
The flame detector of claim 17 wherein the switch-close signal is generated by the HRD signal.
Claim 21
Dependent Claim
21 words
The flame detector of claim 1 wherein the output means full-wave rectifies the AC component thereby providing a rectified flame signal.
Claim 22
Dependent Claim
21 words
The flame detector of claim 20 wherein the output means amplifies the rectified flame signal thereby providing an amplified flame signal.
Claim 23
Dependent Claim
26 words
The flame detector of claim 21 wherein the output means converts the amplified flame signal to substantially a DC signal thereby providing the flame output signal.
Claim 24
Dependent Claim
32 words
The flame detector of claim 1 wherein the flame detector means further comprises a photocell which has a variable, photosensitive resistance that varies as a function of infrared radiation impinged upon it.
Claim 25
Dependent Claim
30 words
The flame detector of claim 23 wherein the photosensitive resistance reaches a dark resistance value when the flame is absent and a light resistance value when the flame is present.
Claim 26
Dependent Claim
30 words
The flame detector of claim 24 wherein the photosensitive resistance varies due to variations in the amount of infrared radiation incident upon the photocell as a result of flame flicker.
Claim 27
Dependent Claim
53 words
The flame detector of claim 25 wherein the DC component of the flame signal represents the dark resistance when the flame is absent and the light resistance when the flame is present, and wherein the AC component of the flame signal represents the changes in the photosensitive resistance due to the flame flicker.
Claim 28
Dependent Claim
19 words
The flame detector of claim 26 wherein the photocell is biased by a voltage in excess of 10 V.
Claim 29
Dependent Claim
143 words
A flame detector for use with a photocell which produces a flame signal when exposed to a flame, the flame detector comprising: input means, coupled to the photocell, for receiving and buffering the flame signal thereby providing a buffered signal; filter means, coupled to the input means, for filtering and amplifying the buffered signal thereby providing a filtered flame signal; output means, coupled to the filter means, for further amplifying the filtered flame signal thereby providing an output flame signal; switch means, coupled to the photocell, for selectively, substantially short circuiting the flame signal to a known voltage value; and hot refractory detection means, coupled to the photocell for detecting a flame-out condition and generating an HRD signal causing the flame signal to be substantially short circuited to a known voltage value thereby eliminating a false flame signal caused by hot refractory shimmering.
Claim 30
Dependent Claim
143 words
A flame detector for use with a photocell which produces a flame signal when exposed to a flame, the flame detector comprising: input means, coupled to the photocell, for receiving and buffering the flame signal thereby providing a buffered signal; filter means, coupled to the input means, for filtering and amplifying the buffered signal thereby providing a filtered flame signal; output means, coupled to the filter means, for further amplifying the filtered flame signal thereby providing an output flame signal; switch means, coupled to the photocell, for selectively, substantially short circuiting the flame signal to a known voltage value; and hot refractory detection means, coupled to the photocell for detecting a flame-out condition and generating an HRD signal causing the flame signal to be substantially short circuited to a known voltage value thereby eliminating a false flame signal caused by hot refractory shimmering.
Claim 31
Dependent Claim
46 words
The flame detector of claim 28 wherein the flame signal, as produced by the photocell, has a DC component, which reaches a flame-out level when the flame-out condition exists and reaches a flame-on level when the flame is present, and which has an AC ripple component.
Claim 32
Dependent Claim
40 words
The flame detector of claim 29 wherein the hot refractory detection means detects a change in the DC component of the flame signal and generates an HRD signal when the DC component of the flame signal reaches the flame-out level.
Claim 33
Dependent Claim
22 words
The flame detector of claim 30 wherein the hot refractory detection means generates the HRD signal for an HRD override time period.
Claim 34
Dependent Claim
34 words
The flame detector of claim 31 wherein the HRD override time period is determined by the shorter of a predetermined time period and a flame-out period representing the time that the flame-out condition exists.
Claim 35
Dependent Claim
37 words
The flame detector of claim 32 wherein the hot refractory detection means stops generating the HRD signal before the predetermined time period is ended where the DC component of the flame signal returns to the flame-on level.
Claim 36
Dependent Claim
28 words
The flame detector of claim 33 wherein the switch means is actuated and substantially short circuits the flame signal to the known voltage upon receiving a switch-close signal.
Claim 37
Dependent Claim
16 words
The flame detector of claim 34 wherein the switch-close signal is generated by the HRD signal.
Claim 38
Dependent Claim
17 words
The flame detector of claim 34 wherein the switch-close signal is generated by an amplifier test pulse.
Claim 39
Dependent Claim
174 words
The flame detector of claim 34 wherein the HRD means further comprises: first amplifier means having a first amplifier input and a first amplifier output; first coupling means, for coupling the photocell to the first amplifier input, where the first coupling means provides a turn-on signal, which is representative of the flame-out level of the DC component of the flame signal, at the first amplifier input for a time period determined by the shorter of the predetermined time period and the flame-out period; second amplifier means, having a first input, a second input and an output, for providing the HRD signal when the flame-out condition exists, where the first input is coupled to the first amplifier output, and the second input is biased and coupled to the output of the second amplifier means such that the output of the second amplifier means provides the HRD signal while the flame-out condition is presented to the first amplifier input; and second coupling means for coupling the output of the second amplifier means to the switch means.
Claim 40
Dependent Claim
17 words
The flame detector of claim 37 wherein the first amplifier means further comprises a common-base connected transistor.
Claim 41
Dependent Claim
93 words
The flame detector of claim 38 wherein the first coupling means further comprises: a capacitor with first and second capacitor terminals; a resistor with first and second resistor terminals; and a diode with first and second diode terminals where the first capacitor terminal is coupled to the photocell and the second capacitor terminal is coupled to the first resistor terminal and where the second resistor terminal is coupled to the input of the common-base connected transistor and also to the first diode terminal, and where the second diode terminal is coupled to ground.
Claim 42
Dependent Claim
16 words
The flame detector of claim 37 wherein the second amplifier means further comprises an operational amplifier.
Claim 43
Dependent Claim
28 words
The flame detector of claim 37 wherein the second coupling means further comprises a diode connected between the output of the second amplifier means and the switch means.
Claim 44
Dependent Claim
120 words
A flame signal amplifier for use with a flame detector that produces a flame signal, having an AC component and a DC component, when exposed to a flame, the flame signal amplifier comprising: input means, coupled to the flame detector, for receiving and buffering the AC component of the flame signal, thereby providing an AC buffered flame signal; filter means, coupled to the input means, for filtering the AC buffered flame signal, thereby providing an AC filtered flame signal; and output means, coupled to the filter means, for full wave rectifying the AC filtered flame signal, amplifying the AC filtered flame signal, and converting the AC filtered flame signal into a flame output signal that is substantially a DC signal.
Claim 45
Dependent Claim
120 words
A flame signal amplifier for use with a flame detector that produces a flame signal, having an AC component and a DC component, when exposed to a flame, the flame signal amplifier comprising: input means, coupled to the flame detector, for receiving and buffering the AC component of the flame signal, thereby providing an AC buffered flame signal; filter means, coupled to the input means, for filtering the AC buffered flame signal, thereby providing an AC filtered flame signal; and output means, coupled to the filter means, for full wave rectifying the AC filtered flame signal, amplifying the AC filtered flame signal, and converting the AC filtered flame signal into a flame output signal that is substantially a DC signal.
Claim 46
Dependent Claim
110 words
The flame signal amplifier of claim 42 wherein the output means further comprises: rectifier means for full wave rectifying the AC filtered flame signal; capacitance means for providing the flame output signal; first amplifier means for amplifying a first half cycle of the AC filtered flame signal to produce a first amplified flame signal and applying it to the capacitance means; and second amplifier means for amplifying a second half cycle of the AC filtered flame signal and to produce a second amplified flame signal and applying it to the capacitance means where the capacitance means charges during the first and second half cycle of the AC filtered flame signal.
Claim 47
Dependent Claim
26 words
The flame signal amplifier of claim 42 wherein the filter means further comprises: a multiple feedback, band pass filter with a first and a second stage.
Claim 48
Dependent Claim
24 words
The flame signal amplifier of claim 44 wherein the first stage is tuned to have a maximum gain at a frequency of 11.3 Hz.
Claim 49
Dependent Claim
25 words
The flame signal amplifier of claim 44 wherein the second stage is tuned to have a maximum gain at a frequency of approximately 14.9 Hz.
Claim 50
Dependent Claim
58 words
The flame signal amplifier of claim 44 wherein the filter means has an overall gain at a frequency of 8.5 Hz and 19.5 Hz that is approximately 20% of the gain at 14.0 Hz, and an overall gain at a frequency of 35.0 Hz and 5.0 Hz which is less than 2% of the gain at 14.0 Hz.
Claim 51
Dependent Claim
34 words
The flame signal amplifier of claim 42, and further comprising: switch means, coupled to the input means, for substantially, selectively short circuiting the AC component of the flame signal to a known voltage level.
Claim 52
Dependent Claim
54 words
The flame signal amplifier of claim 48, and further comprising: hot refractory detection means, coupled to the flame detector, for detecting a flame-out condition and generating an HRD signal causing the flame signal to be substantially short circuited, to a known voltage value thereby eliminating a false flame signal caused by hot refractory shimmering.
Claim 53
Dependent Claim
29 words
The flame signal amplifier of claim 49 wherein the switch means short circuits the AC component of the flame signal to the known voltage upon receiving a switch-close signal.
Claim 54
Dependent Claim
17 words
The flame signal amplifier of claim 50 wherein the switch-close signal is generated by a test pulse.
Claim 55
Dependent Claim
17 words
The flame signal amplifier of claim 51 wherein the switch-close signal is generated by the HRD signal.
Claim 56
Dependent Claim
145 words
A flame detector, comprising: a photocell for producing a flame signal having an AC and a DC component, when exposed to a flame, the photocell producing the flame signal across a first and a second terminal where the first terminal is substantially at ground potential to facilitate bypassing noise to ground; input means, coupled to the photocell, for receiving and buffering the AC component of the flame signal thereby providing an AC buffered flame signal; filter means, coupled to the input means, for filtering the AC buffered flame signal thereby producing an AC filtered flame signal; output means, coupled to the filter means, for amplifying the AC filtered flame signal to provide a flame output signal; and switch means coupled to the input means, for substantially short circuiting the AC component of the flame signal to a known voltage level upon receiving a switch-close signal.
Claim 57
Dependent Claim
145 words
A flame detector, comprising: a photocell for producing a flame signal having an AC and a DC component, when exposed to a flame, the photocell producing the flame signal across a first and a second terminal where the first terminal is substantially at ground potential to facilitate bypassing noise to ground; input means, coupled to the photocell, for receiving and buffering the AC component of the flame signal thereby providing an AC buffered flame signal; filter means, coupled to the input means, for filtering the AC buffered flame signal thereby producing an AC filtered flame signal; output means, coupled to the filter means, for amplifying the AC filtered flame signal to provide a flame output signal; and switch means coupled to the input means, for substantially short circuiting the AC component of the flame signal to a known voltage level upon receiving a switch-close signal.
Claim 58
Dependent Claim
54 words
The flame detector of claim 53 and further comprising hot refractory detection means, coupled to the flame detection means, for detecting a flame-out condition and generating the switch-close signal causing the flame signal to be substantially short circuited to a known voltage value thereby eliminating a false flame signal caused by hot refractory shimmering.
Claim 59
Dependent Claim
16 words
The flame detector of claim 53 wherein the switch-close signal is actuated by a test pulse.
Claim 60
Dependent Claim
20 words
The flame detector of claim 53 wherein the photocell is biased by a voltage which is greater than 10 V.
References Cited (Backward Citations)
US3202976A
Cited
US3299361A
Cited
US3421156A
Cited
US3541549A
Cited
US3742474A
Cited
US3822408A
Cited
US3936648A
Cited
US3820097A
Cited
US3947218A
Cited
US4039844A
Cited
US4033711A
Cited
US4100407A
Cited
US4227155A
Cited
US4235587A
Cited
US4298334A
Cited
US4381455A
Cited
US4370557A
Cited
US4395638A
Cited
US4455487A
Cited
US4540886A
Cited
US4451226A
Cited
US4591725A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-02-26 | 1993-08-28 | 1994-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-26 | 1997-08-28 | 1998-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-26 | 2001-08-28 | 2002-02-27 | $7700.00 | Window Closed / Lapsed |