Overheat detection system

Claim 2

A fire and overheat detection system including in combination: a primary sensor tube having one closed end and one Open end, a reference sensor tube having one closed end and one open end, a primary responder having a housing and an electrically conductive primary diaphragm dividing said housing into (1) a first chamber connected to the open end of said primary sensor tube and provided with a first electrode, and (2) a second chamber connected to the open end of said reference sensor tube and provided with a second electrode, said primary diaphragm normally being out of contact with both said electrodes, the pressure within said first chamber and primary sensor tube normally being significantly greater than the pressure within said second chamber and reference sensor tube, and a confirmation responder having a housing and an electrically conductive confirmation diaphragm electrically connected to said second electrode and dividing said housing into a closed and sealed third chamber and having a third electrode, and a fourth chamber connected to and at the same pressure as said second chamber and having a fourth electrode against which said confirmation diaphragm normally rests in contact therewith.

Claim 3

The system of claim 1 having electrically actuable fault warning means connected on one end to both of said first and fourth electrodes and on the other end to ground, electrically actuable fire and overheat warning means connected on one end to said third electrode and on the other end to ground, and electrical potential means connected to said primary diaphragm, whereby fire or overheat warning is given when (1) the pressure in said primary sensor and said first chamber rises above the pressure in said second chamber sufficiently to force said primary diaphragm into contact with said second electrode and (2) simultaneously the pressure in said reference sensor and in said second and fourth chambers rises to an absolute value high enough to force said confirmation diaphragm against said third electrode, and whereby a change in pressure in said primary sensor, as may be caused by a leak in said primary sensor, causes said primary diaphragm to close, either (a) against said first electrode and produce a fault warning whatever the position of said confirmation diaphragm, or (b) against said second electrode while said confirmation rests against said fourth electrode, also producing a fault warning, and whereby a leak in said reference sensor when it is in an environment at pressure higher than that within said reference sensor, causes a rise in pressure in said second and fourth chambers to move said primary diaphragm into contact with said first electrode and said confirmation diaphragm into contact with said third electrode, resulting in a fault warning whether or not said primary sensor has a leak, and whereby a leak in said reference sensor when it is in an environment at pressure lower than that within said reference sensor, causes a drop in pressure in said second and fourth chambers to move only said primary diaphragm and to move it in contact with said second electrode, thereby producing a fault warning if said primary sensor is not leaking, or if the primary sensor is also leaking will produce a fault warning by said primary diaphragm moving against said first electrode, while if said primary sensor is operative, fire conditions can raise the pressure in said first chamber above atmospheric and cause said primary diaphragm to move against said second electrode and produce a fire warning.

Claim 4

The system of claim 1 wherein said primary and reference sensors are wound together in a double helix to support each other along substantially identical paths in a zone for which detection is desired.

Claim 5

The system of claim 1 wherein at 70* F. the pressure inside said primary sensor and said first chamber is approximately 2 p.s.i.a. and the pressure inside said reference sensor and second and fourth chambers is approximately 1 p.s.i.a.

Claim 6

The system of claim 4 wherein said primary diaphragm is actuaTed to close against said second electrode when the pressure in said first chamber exceeds that in said second chamber by about 2 p.s.i., a small preset pressure, and wherein, under normal operation when both sensors and both responders are free from fault, this occurs when the pressure in said fourth chamber has risen to a level that closes said confirmation diaphragm against said third electrode.

Claim 7

The system of claim 5 wherein said primary diaphragm is urged into contact with said first electrode when the pressure in said first chamber is less than 0.2 p.s.i. above that in said second chamber.

Claim 8

The system of claim 1 wherein each of said primary and reference sensor tubes continuously contains a solid and provides continuous free space and said solid is of the kind that reversibly emits a gas in gross quantities above a predetermined fire temperature and takes it back in below that temperature, thereby producing a marked increase in the pressure in said first chamber when even a short length of said primary sensor is exposed to a temperature above said predetermined fire temperatures.

Claim 9

A fire and overheat detection system including in combination: a primary sensor tube having one closed end and one open end, a reference sensor tube having one closed end and one open end, a primary responder having a housing and an electrically conductive primary diaphragm dividing said housing into a first chamber connected to the open end of said primary sensor tube and provided with a first electrode and a second chamber connected to the open end of said reference sensor tube and provided with a second electrode, said primary diaphragm normally being out of contact with both said electrodes and the pressure within said first chamber and primary sensor tube normally being significantly greater than the pressure within said second chamber and reference sensor tube, a confirmation responder having a housing and an electrically conductive confirmation diaphragm electrically connected to said second electrode and dividing said housing into a closed third chamber at a pressure below that in said reference sensor, and having a third electrode and a fourth chamber connected to and at the same pressure as said reference sensor and having a fourth electrode against which said confirmation diaphragm normally rests in contact therewith, electrically actuable fire and overheat warning means connected on one end to said third electrode and on the other end to ground, and electrical potential means connected to said primary diaphragm, whereby fire or overheat warning is given when (1) the pressure in said primary sensor and said first chamber rises above the pressure in said second chamber sufficiently to force said primary diaphragm into contact with said second electrode and (2) simultaneously the pressure in said reference sensor and in said second and fourth chambers rises to a value high enough to force said confirmation diaphragm against said third electrode.

Claim 10

A fire and overheat detection system including in combination: a primary sensor tube having one closed end and one open end, a reference sensor tube having one closed end and one open end, a primary responder having a housing and an electrically conductive primary diaphragm dividing said housing into a first chamber connected to the open end of said primary sensor tube and provided with a first electrode and a second chamber connected to the open end of said reference sensor tube and provided with a second electrode, said primary diaphragm normally being out of contact with both said electrodes and the pressure within said first chamber and primary sensor tube normally being significantly greater than the pressure within said second chamber and reference sensor tube, a confirmation responder having a housing and an electrically conductive confirmation diaphragm electrically connected to said second electrode and dividing said housing into a closed third chamber at a pressure below that in said reference sensor, and having a third electrode and a fourth chamber connected to and at the same pressure as said reference sensor and having a fourth electrode against which said confirmation diaphragm normally rests in contact therewith, electrically actuable fire and overheat warning means connected on one end to said third electrode and on the other end to ground, and electrical potential means connected to said primary diaphragm, whereby fire or overheat warning is given when (1) the pressure in said primary sensor and said first chamber rises above the pressure in said second chamber sufficiently to force said primary diaphragm into contact with said second electrode and (2) simultaneously the pressure in said reference sensor and in said second and fourth chambers rises to a value high enough to force said confirmation diaphragm against said third electrode.

Claim 11

The system of claim 8 wherein said primary and reference sensors are wound together and extend along substantially identical paths in a zone for which detection is desired.

Claim 12

The system of claim 8 wherein said primary diaphragm is actuated to close against said second electrode when the pressure in said first chamber exceeds that in said second chamber by about 2 p.s.i., and wherein under normal operation, when both sensors and both responders are free from fault, this occurs when the pressure in said fourth chamber has risen to a level that closes said confirmation diaphragm against said third electrode.

Claim 13

The system of claim 10 wherein said primary diaphragm is urged into contact with said first electrode when the pressure in said first chamber is less than 0.2 p.s.i., above that in said second chamber.

Claim 14

The system of claim 8 wherein each of said primary and reference sensor tubes contains solid and continuous free space and said soliD is of the kind that reversibly emits a gas in gross quantities above a predetermined fire temperature and takes it back in below that temperature, thereby producing a marked increase in the pressure in said first chamber when even a short length of said primary sensor is exposed to a temperature above said predetermined fire temperature.

Claim 15

A fire and overheat detection system, including in combination: a primary sensor tube having one closed end and one responder end, said tube containing a solid that reversibly emits gas in gross quantities above a predetermined temperature and takes it back below that temperature, there being a continuous free space around said solid in said primary sensor tube, said free space containing gas at about 2 p.s.i.a., a reference sensor tube having one closed end and one responder end and containing gas at about 1 p.s.i.a., a primary responder having a housing and an electrically conductive primary diaphragm dividing said housing into a first chamber connected to the responder end of said primary sensor tube and provided with a first electrode and a second chamber connected to the responder end of said reference sensor tube and provided with a second electrode, said primary diaphragm normally being out of contact with both said electrodes, a confirmation responder having a housing and an electrically conductive confirmation diaphragm electrically connected to said second electrode and dividing said housing into a closed third chamber at vacuum and having a third electrode and a fourth chamber connected to and at the same pressure as said second chamber and having a fourth electrode against which said confirmation diaphragm normally rests in contact therewith, electrically actuable fault warning means connected on one end to both of said first and fourth electrodes and on the other end to ground, electrically actuable fire and overheat warning means connected on one end to said third electrode and on the other end to ground, and electrical potential means connected to said primary diaphragm.

Claim 16

A fire and overheat detection system, including in combination: a primary sensor tube having one closed end and one responder end, said tube containing a solid that reversibly emits gas in gross quantities above a predetermined temperature and takes it back below that temperature, there being a continuous free space around said solid in said primary sensor tube, said free space containing gas at about 2 p.s.i.a., a reference sensor tube having one closed end and one responder end and containing gas at about 1 p.s.i.a., a primary responder having a housing and an electrically conductive primary diaphragm dividing said housing into a first chamber connected to the responder end of said primary sensor tube and provided with a first electrode and a second chamber connected to the responder end of said reference sensor tube and provided with a second electrode, said primary diaphragm normally being out of contact with both said electrodes, a confirmation responder having a housing and an electrically conductive confirmation diaphragm electrically connected to said second electrode and dividing said housing into a closed third chamber at vacuum and having a third electrode and a fourth chamber connected to and at the same pressure as said second chamber and having a fourth electrode against which said confirmation diaphragm normally rests in contact therewith, electrically actuable fault warning means connected on one end to both of said first and fourth electrodes and on the other end to ground, electrically actuable fire and overheat warning means connected on one end to said third electrode and on the other end to ground, and electrical potential means connected to said primary diaphragm.

Claim 17

The system of claim 13 wherein said primary and reference sensors are wound together in a double helix to support each other along substantially identical paths in a zone for which detection is desired.

Claim 18

The system of claim 13 wherein said primary diaphragm is actuated to close against said second electrode when the pressure in said first chamber exceeds that in said second chamber by about 2 p.s.i., and wherein, under normal operation, when both sensors and both responders are free from fault, this occurs when the pressure in said fourth chamber has risen to a level that closes said confirmation diaphragm against said third electrode.

Claim 19

The system of claim 13 wherein said primary diaphragm is urged into contact with said first electrode when the pressure in said first chamber is less than 0.2 p.s.i., above that in said second chamber.

Claim 20

A fire and overheat detection system including in combination: tubular sensor means having one end closed and one end open, a primary responder having a housing connected to an open end of said sensor means, and first pressure-responsive means, and a confirmation responder having a housing connected to said open end of said sensor means and second pressure-responsive means, said first pressure-responsive means being a first metal diaphragm, said primary responder having a first electrode isolated electrically from said first diaphragm and against which said first diaphragm moves to actuate a warning, said first diaphragm normally being out of contact with said first electrode except when actuated by an increase of pressure in said sensor, said second pressure-responsive means being a second metal diaphragm electrically connected to said first diaphragm, said confirmation responder having an electrode against which said second diaphragm normally rests, except when moved away therefrom by an abnormal drop of pressure in sAid sensor.

Claim 21

A fire and overheat detection system including in combination: tubular sensor means having one end closed and one end open, a primary responder having a housing connected to an open end of said sensor means, and first pressure-responsive means, and a confirmation responder having a housing connected to said open end of said sensor means and second pressure-responsive means, said first pressure-responsive means being a first metal diaphragm, said primary responder having a first electrode isolated electrically from said first diaphragm and against which said first diaphragm moves to actuate a warning, said first diaphragm normally being out of contact with said first electrode except when actuated by an increase of pressure in said sensor, said second pressure-responsive means being a second metal diaphragm electrically connected to said first diaphragm, said confirmation responder having an electrode against which said second diaphragm normally rests, except when moved away therefrom by an abnormal drop of pressure in sAid sensor.

Claim 22

A temperature differential detection system including in combination: a first sensor tube having one closed end and one open end, a second sensor tube having one closed end and one open end, a first responder having a housing and an electrically conductive first diaphragm dividing said housing into (1) a first chamber connected to the open end of said first sensor tube and provided with a first electrode, and (2) a second chamber connected to the open end of said second sensor tube and provided with a second electrode, said first diaphragm normally being out of contact with both said electrodes, the pressure within said first chamber and first sensor tube normally being the same as the pressure within said second chamber and second sensor tube, and a second responder having a housing and an electrically conductive second diaphragm electrically connected to said second electrode and dividing said housing into a closed and sealed third chamber and having a third electrode, and a fourth chamber connected to and at the same pressure as said second chamber and having a fourth electrode against which said second diaphragm normally rests in contact therewith.

Claim 23

A temperature differential detection system including in combination: a first sensor tube having one closed end and one open end, a second sensor tube having one closed end and one open end, a first responder having a housing and an electrically conductive first diaphragm dividing said housing into (1) a first chamber connected to the open end of said first sensor tube and provided with a first electrode, and (2) a second chamber connected to the open end of said second sensor tube and provided with a second electrode, said first diaphragm normally being out of contact with both said electrodes, the pressure within said first chamber and first sensor tube normally being the same as the pressure within said second chamber and second sensor tube, and a second responder having a housing and an electrically conductive second diaphragm electrically connected to said second electrode and dividing said housing into a closed and sealed third chamber and having a third electrode, and a fourth chamber connected to and at the same pressure as said second chamber and having a fourth electrode against which said second diaphragm normally rests in contact therewith.

Claim 24

A fire and overheat detection system including in combination: tubular sensor means having one end closed and one end open, a primary responder having a housing connected to an open end of said sensor means, and first pressure-responsive means, and a confirmation responder having a housing connected to said open end of said sensor means and second pressure-responsive means, said first pressure-responsive means being a first metal diaphragm, said primary responder having a metal housing electrically connected to said first diaphragm and a first electrode isolated electrically from said housing and against which said first diaphragm moves to actuate a warning, said first diaphragm normally being out of contact with said first electrode except when actuated by an increase of pressure in said sensor, said second pressure-responsive means being a second metal diaphragm electrically connected to said first diaphragm, said confirmation responder having a metal housing electrically connected to said second diaphragm and an electrode against which said second diaphragm normally rests, except when moved away therefrom by an abnormal drop of pressure in said sensor.

Claim 25

A fire and overheat detection system including in combination: tubular sensor means having one end closed and one end open, a primary responder having a housing connected to an open end of said sensor means, and first pressure-responsive means, and a confirmation responder having a housing connected to said open end of said sensor means and second pressure-responsive means, said first pressure-responsive means being a first metal diaphragm, said primary responder having a metal housing electrically connected to said first diaphragm and a first electrode isolated electrically from said housing and against which said first diaphragm moves to actuate a warning, said first diaphragm normally being out of contact with said first electrode except when actuated by an increase of pressure in said sensor, said second pressure-responsive means being a second metal diaphragm electrically connected to said first diaphragm, said confirmation responder having a metal housing electrically connected to said second diaphragm and an electrode against which said second diaphragm normally rests, except when moved away therefrom by an abnormal drop of pressure in said sensor.

Claim 26

The system of claim 19 having a current source, a first lead connecting said source to said first electrode, an alarm system, a second lead connecting the housing of said confirmation responder to said alarm system.

Claim 27

The system of claim 20 having a switch connected on one side to said first lead, a third lead connecting the other side of said switch to said second electrode.

Claim 28

The system of claim 21 having a fault monitor circuit connected across said switch.

Claim 29

The system of claim 20 having a switch connected to said first lead, an adjustable resistor connected to said sensor near its open end, the closed end of said sensor being grounded, and a third lead connecting said switch to said resistor.

Claim 30

A fire and overheat detection system including in combination: tubular sensor means having one end closed and one end open, a primary responder having a housing and an electrically conductive primary diaphragm dividing said housing into (1) a first chamber connected to an open end of said sensor means, and (2) a closed and sealed second chamber provided with a first electrode, said primary diaphragm normally being out of contact with the electrode, and actuated to move thereagainst at a pressure which is different from the ambient pressure, a confirmation responder having a housing and an electrically conductive confirmation diaphragm dividing its said housing into a third chamber at ambient pressure and a fourth chamber connected to said open end of said sensor means, and an electrode in one of sAid third and fourth chambers against which said diaphragm is normally seated and from which it moves away when said sensor reaches said ambient pressure.

Claim 31

A fire and overheat detection system including in combination: tubular sensor means having one end closed and one end open, a primary responder having a housing and an electrically conductive primary diaphragm dividing said housing into (1) a first chamber connected to an open end of said sensor means, and (2) a closed and sealed second chamber provided with a first electrode, said primary diaphragm normally being out of contact with the electrode, and actuated to move thereagainst at a pressure which is different from the ambient pressure, a confirmation responder having a housing and an electrically conductive confirmation diaphragm dividing its said housing into a third chamber at ambient pressure and a fourth chamber connected to said open end of said sensor means, and an electrode in one of sAid third and fourth chambers against which said diaphragm is normally seated and from which it moves away when said sensor reaches said ambient pressure.

Claim 32

The system of claim 24 having a third electrode in said chamber of said confirmation responder other than that containing said second electrode, so that whether said sensor is normally above or below said ambient pressure said confirmation diaphragm will be normally seated against a said electrode and will not be seated against either said electrode at ambient pressure.

Claim 33

The system of claim 25 having an expandable bellows connected to said third chamber for keeping it at ambient pressure.

Claim 34

The system of claim 21, wherein said second and third electrodes are electrically connected together.

Claim 35

The system of claim 24 wherein said primary and confirmation diaphragms are electrically connected together.

Claim 36

The system of claim 28 wherein a power source is connected to said second electrode, alarm means is connected to said first electrode, a resistor is placed between said diaphragms and ground, and a fault indicator is connected in series between said power source and said primary diaphragm, said fault indicator being actuable at a lower current demand than said alarm.