US5059953A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Infrared overheat and fire detection system
Assignee: Pacific Scientific Co
•
Filing: 1990-04-10
•
Granted: 1991-10-22
•
Expires: 2010-04-10
Abstract
Abstract A system for detecting an overheat condition in aircraft preferably includes two control units each connected to eight thermal imaging modules. The thermal imaging modules monitor the cargo by for an overheat condition and if any module detects an overheat condition, the control unit verifies the overheat condition and then triggers an alarm. The control units execute routines to monitor and test their operational status and that of each thermal imaging module. The control units are connected to the aircraft electronics to indicate the location of an overheat condition or any malfunctioning control units and thermal imaging modules. The thermal imaging modules are identical to each other and include an infrared detector, a rotating optical assembly, threshold circuitry and a motor. The optical assembly is rotated by the motor to provide the detector with a conical field of view. The optical assembly focuses the radiation in the cargo bay on the infrared detector. If the infrared detector measures a radiation level equal or greater than that of a fire, the threshold circuitry outputs an overheat signal to the control unit. The thermal imaging module also includes a thermal switch that will trigger an overheat signal if the temperature of the module itself is above a specified temperature.
Inventors
- 👤 Michael L. Parsons
- 👤 Peter L. Hutchins
- 👤 Yeong-Jeng V. Tseng
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:53
CPC Classifications
G; G08; G08B; G08B31/00; G08B17/00; G08B17/12
Claims Analysis
Total Claims: 46
Claim 1
Independent Claim
114 words
A system for detecting fire comprising: an aircraft having a cargo bay capable of holding cargo in cargo containers; a plurality of cargo containers in said bay; a control unit attached to said aircraft; and a plurality of thermal imaging modules coupled to said control unit and positioned in direct view of said cargo containers, said thermal imaging modules having an infrared detector for sensing an overheat condition on the outside of said cargo bay containers indicating a fire within said containers and outputting a signal to said control unit, said thermal imaging modules also sized and positioned in said cargo bay to not interfere with the loading and unloading of said cargo bay.
Claim 2
Independent Claim
114 words
A system for detecting fire comprising: an aircraft having a cargo bay capable of holding cargo in cargo containers; a plurality of cargo containers in said bay; a control unit attached to said aircraft; and a plurality of thermal imaging modules coupled to said control unit and positioned in direct view of said cargo containers, said thermal imaging modules having an infrared detector for sensing an overheat condition on the outside of said cargo bay containers indicating a fire within said containers and outputting a signal to said control unit, said thermal imaging modules also sized and positioned in said cargo bay to not interfere with the loading and unloading of said cargo bay.
Claim 3
Dependent Claim
35 words
The system of claim 1, wherein said thermal imaging modules include an optical assembly that rotates to increase the field of view of said infrared detector and thereby increase the sensitivity of said infrared detector.
Claim 4
Dependent Claim
46 words
The system of claim 1, wherein each of said thermal imaging modules views a portion of the cargo bay, and wherein said thermal imaging modules are mounted in the cargo bay with most areas of the cargo bay viewed by two of said thermal imaging modules.
Claim 5
Dependent Claim
62 words
The system of claim 1, wherein a first and a last thermal imaging module are connected to said control unit with the remaining thermal imaging modules connected between said first and said last thermal imaging modules, and wherein each said thermal imaging module comprises an interface multiplexer thereby allowing bi-directional communication between each of said thermal imaging modules and said control unit.
Claim 6
Independent Claim
181 words
A system for detecting fire in an aircraft having an electronic system, comprising: a control unit; at least one thermal imaging module connected to said control unit, said module comprising: an infrared detector that outputs a signal corresponding to the level of infrared radiation; a stationary housing mounted to the aircraft, said stationary housing protecting said infrared detector positioned therein; a rotating optical assembly attached to said housing for directing infrared radiation toward said infrared detector from plural directions; a circuit connected to receive said signal output of said infrared detector and connected to provide an overheat signal to said control unit if the output from said infrared detector is above a predetermined level, said circuit connected to monitor the rotation of said optical assembly and output a fault signal to the control unit if rotation is below a preset speed; and a connector for connecting said control unit to said electronic system in said aircraft, wherein said control unit monitors said module for an overheat or fault signal and outputs a fire or fault signal if the condition is verified.
Claim 7
Independent Claim
181 words
A system for detecting fire in an aircraft having an electronic system, comprising: a control unit; at least one thermal imaging module connected to said control unit, said module comprising: an infrared detector that outputs a signal corresponding to the level of infrared radiation; a stationary housing mounted to the aircraft, said stationary housing protecting said infrared detector positioned therein; a rotating optical assembly attached to said housing for directing infrared radiation toward said infrared detector from plural directions; a circuit connected to receive said signal output of said infrared detector and connected to provide an overheat signal to said control unit if the output from said infrared detector is above a predetermined level, said circuit connected to monitor the rotation of said optical assembly and output a fault signal to the control unit if rotation is below a preset speed; and a connector for connecting said control unit to said electronic system in said aircraft, wherein said control unit monitors said module for an overheat or fault signal and outputs a fire or fault signal if the condition is verified.
Claim 8
Dependent Claim
34 words
The system of claim 5, further comprising a switch attached to said module, said switch outputting an overheat signal to said control unit if the temperature of said switch is above a predetermined level.
Claim 9
Dependent Claim
24 words
The system of claim 6, wherein said switch outputs an overheat signal if the temperature of said switch is greater than about 85° C.
Claim 10
Dependent Claim
41 words
The system of claim 5, further comprising a remote status display connected to said control unit and located in or near a cargo bay of the aircraft, said remote status display having indicator lamps to signal the presence of a fire.
Claim 11
Dependent Claim
27 words
The system of claim 5, wherein said circuit provides an overheat signal to said control unit if the infrared detector indicates a temperature greater than 200° C.
Claim 12
Dependent Claim
25 words
The system of claim 5, wherein said thermal imaging module further comprises a motor and a motor control circuit attached to rotate said optical assembly.
Claim 13
Dependent Claim
18 words
The system of claim 10, wherein said motor rotates said optical assembly at about one revolution per second.
Claim 14
Dependent Claim
88 words
The system of claim 5, wherein said optical assembly further comprises: a cover attached to said housing, said cover being rotatable with respect to said housing and substantially preventing radiation from passing therethrough, said cover defining an opening which allows infrared radiation to pass to said infrared detector; a reflector mounted in said cover, said reflector directing radiation entering through said opening to said detector; and a lens for focusing radiation of said infrared detector or said reflector, said lens being mounted in said opening of said cover.
Claim 15
Dependent Claim
21 words
The system of claim 12, wherein said lens of said optical assembly provides a field of view approximately 10° by 70°.
Claim 16
Dependent Claim
35 words
The system of claim 12, wherein said lens of said optical assembly comprises seven lenses each having a conical field of view of approximately 10°, said lenses having their beam centers spaced radially every 10°.
Claim 17
Dependent Claim
95 words
The system of claim 5, wherein said circuit further comprises: an amplifier connected to the output of said infrared detector to magnify the signal output by said infrared detector; a threshold circuit connected to the output of said amplifier, said threshold circuit comparing the signal from said amplifier and asserting an output signal if the level of the signal from said amplifier is above a preset level; and an interface multiplexer coupled to said control unit and said threshold circuit, said interface multiplexer controlling the communication between said control unit and said thermal imaging module.
Claim 18
Dependent Claim
21 words
The system of claim 15, wherein said amplifier comprises a series connection of a differential amplifier and a high gain amplifier.
Claim 19
Dependent Claim
15 words
The system of claim 15, wherein said threshold circuit comprises two counters and a comparator.
Claim 20
Dependent Claim
20 words
The system of claim 15, wherein said interface circuit comprises an RC timer, a monostable multivibrator and a transmission gate.
Claim 21
Dependent Claim
75 words
The system of claim 5, wherein said thermal imaging module further comprises: an infrared emitter attached near said infrared detector; and self-test logic coupled to said infrared emitter to provide pulses which cause said infrared emitter to produce infrared radiation equivalent to infrared radiation produced by a fire, said self-test logic also coupled to said control unit which provides a signal to said self-test logic to initiate production of infrared radiation for testing the system.
Claim 22
Dependent Claim
31 words
The system of claim 19, wherein said self-test logic comprises a comparator and a pulse generator which output a series of pulses in response to a signal from the control unit.
Claim 23
Dependent Claim
14 words
The system of claim 5, wherein said control unit is a microprocessor and memory.
Claim 24
Independent Claim
114 words
An apparatus for detecting an overheat condition comprising: an infrared detector that outputs a signal corresponding to the level of infrared radiation; a stationary housing protecting said infrared detector with said infrared detector positioned therein; a rotating optical assembly attached to said housing for directing infrared radiation to said infrared detector from plural directions; and a circuit connected to receive the output of said infrared detector and to provide an overheat signal if the output from said infrared detector is above a predetermined level; said circuit also connected to monitor the rotation of said optical assembly and to provide a fault signal if said optical assembly rotates at a rate below a preset level.
Claim 25
Independent Claim
114 words
An apparatus for detecting an overheat condition comprising: an infrared detector that outputs a signal corresponding to the level of infrared radiation; a stationary housing protecting said infrared detector with said infrared detector positioned therein; a rotating optical assembly attached to said housing for directing infrared radiation to said infrared detector from plural directions; and a circuit connected to receive the output of said infrared detector and to provide an overheat signal if the output from said infrared detector is above a predetermined level; said circuit also connected to monitor the rotation of said optical assembly and to provide a fault signal if said optical assembly rotates at a rate below a preset level.
Claim 26
Dependent Claim
30 words
The apparatus of claim 22, further comprising a switch attached to said housing, said switch outputting an overheat signal if the temperature of said switch is above a predetermined level.
Claim 27
Dependent Claim
32 words
The apparatus of claim 22, further comprising a motor and a motor control circuit attached to rotate said optical assembly to provide said infrared detector with a substantially conical field of view.
Claim 28
Dependent Claim
18 words
The apparatus of claim 24, wherein said motor rotates said optical assembly at about one rotation per second.
Claim 29
Dependent Claim
84 words
The apparatus of claim 22, wherein said optical assembly further comprises: a cover attached to said housing, said cover being rotatable with respect to said housing and substantially preventing radiation from passing therethrough, said cover defining an opening which allows infrared radiation to pass to said infrared detector; a reflector mounted in said cover, said reflector directing radiation entering through said opening to said detector; and a lens for focusing radiation on said reflector, said lens being mounted in said opening of said cover.
Claim 30
Dependent Claim
21 words
The apparatus of claim 26, wherein said lens of said optical assembly provides a field of view approximately 10° by 70°.
Claim 31
Dependent Claim
35 words
The apparatus of claim 27, wherein said lens of said optical assembly comprises seven lenses each having a conical field of view of approximately 10°, said lenses having their beam centers spaced radially every 10°.
Claim 32
Dependent Claim
94 words
The apparatus of claim 22, wherein said circuit further comprises: an amplifier connected to the output of said infrared detector to magnify the signal output by the infrared detector; a threshold circuit connected to the output of said amplifier, said threshold circuit comparing the signal from said amplifier and asserting a signal if the level of the signal from said amplifier is above a preset level; and an interface multiplexer coupled to said control unit and said threshold circuit, said interface multiplexer controlling the communication between said control unit and said thermal imaging module.
Claim 33
Dependent Claim
21 words
The apparatus of claim 29, wherein said amplifier is a series connection of a differential amplifier and a high gain amplifier.
Claim 34
Dependent Claim
15 words
The apparatus of claim 29, wherein said threshold circuit comprises two counters and a comparator.
Claim 35
Dependent Claim
20 words
The apparatus of claim 29, wherein said interface circuit comprises an RC timer, a monostable multivibrator and a transmission gate.
Claim 36
Dependent Claim
62 words
The apparatus of claim 22, wherein said thermal imaging module further comprises: an infrared emitter attached near said infrared detector; and a pulse generator which outputs a series of pulses to test the apparatus, said pulse generator coupled to said infrared emitter to produce infrared radiation equivalent to infrared radiation produced by a fire, said pulse generator responsive to a test signal.
Claim 37
Independent Claim
353 words
A system for use with aircraft electronics to detect the presence of fire in the cargo bay of the aircraft, said system comprising: a first plurality of thermal imaging modules positioned to view the entire area of the cargo bay, each of said thermal imaging modules measuring infrared radiation in a portion of the cargo bay and outputting an overheat signal if an overheat condition is detected or a fault signal if the module is defective; a first control unit coupled to the aircraft electronics for receiving test signals and sending fault and fire detect signals, said first control unit also coupled to said first plurality of modules for receiving overheat and fault signals from said modules and sending a test signal to said modules; a second plurality of thermal imaging modules positioned to view the entire area of the cargo bay, each of said thermal imaging modules measuring infrared radiation in a portion of the cargo bay and outputting an overheat signal if an overheat condition is detected or a fault signal if the module is defective; a second control unit coupled to the first control unit for receiving test signals, said second control unit coupled to the aircraft electronics for sending fault and fire detect signals, said second control unit also coupled to said second plurality of modules for receiving overheat and fault signals from said modules and sending a test signal to said modules; and wherein each of said modules connected to said first and said second control units comprises: an infrared detector that outputs a signal corresponding to the level of infrared radiation; a stationary housing mounted to the aircraft, said stationary housing protecting said infrared detector with infrared detector positioned therein; an optical assembly attached to said housing for directing infrared radiation toward said infrared detector; a circuit connected to receive input from said infrared detector and to output an overheat signal if the output from said infrared detector is above a predetermined level; and a switch attached to said module, said switch outputting an overheat signal if the temperature of said switch is above a predetermined level.
Claim 38
Independent Claim
353 words
A system for use with aircraft electronics to detect the presence of fire in the cargo bay of the aircraft, said system comprising: a first plurality of thermal imaging modules positioned to view the entire area of the cargo bay, each of said thermal imaging modules measuring infrared radiation in a portion of the cargo bay and outputting an overheat signal if an overheat condition is detected or a fault signal if the module is defective; a first control unit coupled to the aircraft electronics for receiving test signals and sending fault and fire detect signals, said first control unit also coupled to said first plurality of modules for receiving overheat and fault signals from said modules and sending a test signal to said modules; a second plurality of thermal imaging modules positioned to view the entire area of the cargo bay, each of said thermal imaging modules measuring infrared radiation in a portion of the cargo bay and outputting an overheat signal if an overheat condition is detected or a fault signal if the module is defective; a second control unit coupled to the first control unit for receiving test signals, said second control unit coupled to the aircraft electronics for sending fault and fire detect signals, said second control unit also coupled to said second plurality of modules for receiving overheat and fault signals from said modules and sending a test signal to said modules; and wherein each of said modules connected to said first and said second control units comprises: an infrared detector that outputs a signal corresponding to the level of infrared radiation; a stationary housing mounted to the aircraft, said stationary housing protecting said infrared detector with infrared detector positioned therein; an optical assembly attached to said housing for directing infrared radiation toward said infrared detector; a circuit connected to receive input from said infrared detector and to output an overheat signal if the output from said infrared detector is above a predetermined level; and a switch attached to said module, said switch outputting an overheat signal if the temperature of said switch is above a predetermined level.
Claim 39
Independent Claim
201 words
A system for detecting fire comprising: a control unit; a plurality of thermal imaging modules for detecting a fire or overheat condition, said thermal imaging modules further comprising: an infrared detector; an optical assembly for directing infrared radiation toward said detector; a circuit connected to said detector to receive input from said detector and output an overheat signal; and an interface multiplexer connected to said circuit and coupled for communication with said control unit, said interface multiplexer having two data lines and two address lines, said interface multiplexer capable of both inputting and outputting signals on said data and address lines; and wherein said plurality of thermal imaging units are coupled by a daisy chain connection with a data line and an address line between each of said thermal imaging modules, a first thermal imaging module in said chain connected to said control unit and a last thermal imaging module in said chain connected to said control unit, thereby providing bi-directional communication in which any thermal imaging module may communicate with said control unit using either the connection of said first thermal imaging module to said control unit or the connection of said last thermal imaging module to said control unit.
Claim 40
Independent Claim
201 words
A system for detecting fire comprising: a control unit; a plurality of thermal imaging modules for detecting a fire or overheat condition, said thermal imaging modules further comprising: an infrared detector; an optical assembly for directing infrared radiation toward said detector; a circuit connected to said detector to receive input from said detector and output an overheat signal; and an interface multiplexer connected to said circuit and coupled for communication with said control unit, said interface multiplexer having two data lines and two address lines, said interface multiplexer capable of both inputting and outputting signals on said data and address lines; and wherein said plurality of thermal imaging units are coupled by a daisy chain connection with a data line and an address line between each of said thermal imaging modules, a first thermal imaging module in said chain connected to said control unit and a last thermal imaging module in said chain connected to said control unit, thereby providing bi-directional communication in which any thermal imaging module may communicate with said control unit using either the connection of said first thermal imaging module to said control unit or the connection of said last thermal imaging module to said control unit.
Claim 41
Independent Claim
199 words
A system for detecting fire comprising: a control unit producing an inquisition signal and receiving data; a plurality of thermal imaging modules for detecting a fire or overheat condition, said thermal imaging modules further comprising: an infrared detector; an optical assembly for directing infrared radiation toward said detector; a circuit connected to said infrared detector to receive input from said detector and output an overheat signal; and an interface multiplexer connected to said circuit and coupled for communication with said control unit, said interface multiplexer receiving said inquisition signal on an address line, said interface multiplexer outputting data on a data line and said inquisition signal on a second address line after a preset delay in response to said inquisition signal; and wherein said plurality of thermal imaging modules are daisy chain connected with one data line and one address line between each of said thermal imaging modules, a first thermal imaging module in said chain connected to said control unit, thereby defining a series of time slots in which each thermal imaging module may respond to said inquisition signal, said time slots being defined by the amount of delay from the previous thermal imaging modules in the chain.
Claim 42
Independent Claim
199 words
A system for detecting fire comprising: a control unit producing an inquisition signal and receiving data; a plurality of thermal imaging modules for detecting a fire or overheat condition, said thermal imaging modules further comprising: an infrared detector; an optical assembly for directing infrared radiation toward said detector; a circuit connected to said infrared detector to receive input from said detector and output an overheat signal; and an interface multiplexer connected to said circuit and coupled for communication with said control unit, said interface multiplexer receiving said inquisition signal on an address line, said interface multiplexer outputting data on a data line and said inquisition signal on a second address line after a preset delay in response to said inquisition signal; and wherein said plurality of thermal imaging modules are daisy chain connected with one data line and one address line between each of said thermal imaging modules, a first thermal imaging module in said chain connected to said control unit, thereby defining a series of time slots in which each thermal imaging module may respond to said inquisition signal, said time slots being defined by the amount of delay from the previous thermal imaging modules in the chain.
Claim 43
Independent Claim
124 words
A system for detecting fire comprising: a control unit; a plurality of thermal imaging modules for detecting a fire or an overheat condition, said thermal imaging modules further comprising: an infrared detector; a rotating optical assembly for directing infrared radiation toward said detector; a control circuit connected to regulate the rotation rate of said optical assembly, said control circuit outputting a signal indicating a rotation of said optical assembly; and a circuit connected to receive input from said detector and said control circuit, said circuit outputting an overheat signal to said control unit if the output of said detector indicates an overheat condition in a preset number of consecutive rotations of said optical assembly as indicated by the output signal from said control circuit.
Claim 44
Independent Claim
124 words
A system for detecting fire comprising: a control unit; a plurality of thermal imaging modules for detecting a fire or an overheat condition, said thermal imaging modules further comprising: an infrared detector; a rotating optical assembly for directing infrared radiation toward said detector; a control circuit connected to regulate the rotation rate of said optical assembly, said control circuit outputting a signal indicating a rotation of said optical assembly; and a circuit connected to receive input from said detector and said control circuit, said circuit outputting an overheat signal to said control unit if the output of said detector indicates an overheat condition in a preset number of consecutive rotations of said optical assembly as indicated by the output signal from said control circuit.
Claim 45
Independent Claim
115 words
A method for detecting fire in a cargo bay of an aircraft comprising the steps of: mounting a control unit in the aircraft; positioning a plurality of thermal imaging modules having an infrared detector for sensing the presence of fire in the cargo bay to view a substantial portion thereof and not interfere with loading and unloading of the cargo bay; coupling said control unit to each of said thermal imaging modules; sensing the presence of an overheat or fire condition with said thermal imaging modules; and signaling an overheat condition with said control unit if any of said thermal imaging modules senses a fire or overheat condition in the cargo bay of the aircraft.
Claim 46
Independent Claim
115 words
A method for detecting fire in a cargo bay of an aircraft comprising the steps of: mounting a control unit in the aircraft; positioning a plurality of thermal imaging modules having an infrared detector for sensing the presence of fire in the cargo bay to view a substantial portion thereof and not interfere with loading and unloading of the cargo bay; coupling said control unit to each of said thermal imaging modules; sensing the presence of an overheat or fire condition with said thermal imaging modules; and signaling an overheat condition with said control unit if any of said thermal imaging modules senses a fire or overheat condition in the cargo bay of the aircraft.
References Cited (Backward Citations)
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Cited
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-10-21 | 1995-04-22 | 1995-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-10-21 | 1999-04-22 | 1999-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-10-21 | 2003-04-22 | 2003-10-22 | $7700.00 | Window Closed / Lapsed |