The invention relates generally to electronic thermal sensors which may be used in clothing that is subjected to environmental stresses such as open flame and elevated temperature. More specifically, the invention relates to clothing such as, for example, turnout gear worn by fire-fighters which is capable of monitoring and reporting increasing temperature.
Intelligent clothing, especially in hazardous environments can often mean the difference between life and death. Environmental extremes such as extremes in temperature, and exposure to elemental hazards like liquids, gases and solids that can detrimentally affect ambient conditions all must be considered.
Whether considering applications such as undersea or stellar exploration or the more mundane aspects of controlling natural disasters, protective clothing is a first priority. One application which occurs routinely throughout the world is fire protection. Fire protection or fire-fighting, as it is generically regarded, has historically been undertaken with an assortment of equipment that has evolved over time to become more technologically sophisticated.
Fire-fighters have tended to wear an assortment of equipment that serves at least two functions, protection from physical harm and protection from heat. Fire gear has traditionally emphasized the use of helmets, protective boots, as well as multi-layer pants and jackets. Protective pants and jackets used by fire-fighters are commonly known as “″turn out” gear.
Turn out gear may take many styles, forms and fashions. Boots and bunker pants tend to work together to provide protection over the fire-fighter's lower extremities, seat and legs. Often times, bunker pants can be substituted for high boots and a long bunker jacket. At the same time, a bunker jacket is generally worn by the fire-fighter to protect his upper extremities.
The more traditional piece of turnout gear is the fire-fighter's jacket or bunker coat. A bunker coat is a system which generally includes one or more layers designed to insulate the fire-fighter from physical harm and temperature extreme while absorbing moisture. Traditionally, the outer layer of the coat protects against physical harm such as open flame while the inner layer of the coat provides thermal insulation. Moisture insulation may also be provided by added layers.
Fire-fighting is characterized by extreme stress caused by any number of factors. Periods of extreme physical exertion, for example, carrying heavy rescue equipment while performing physically demanding tasks, exposure to critical temperatures and hazardous substances all contribute to this stress. While protective clothing insulates firemen from the worst effects of external heat sources, it is heavy and the very nature of the clothing, for example use of vapor barrier materials, effectively inhibits the passage of heat away from the body.
Physical exertion causes fire-fighters to sweat. Aggravated by thermal stress from working in a hot environment, the body attempts to lose excess heat by directing blood flow to the skin. This reduces blood flow to vital organs, leads to dehydration, salt loss and increased heart rate. This phenomenon is known as heat stress and has symptoms which include fatigue, confusion, renal failure and eventually cardiac arrest.
Heat stress has been recognized for many years. That the symptoms of heat stress can be made more critical by the poor physical condition and weight of some fire-fighters is also well known. The demand for ever increasing levels of protection from external heat have further exacerbated the problem. As materials are developed that increase heat insulation fire-fighters have been forced to find new ways to sense ambient temperature on the fire ground. Previously it was common practice to keep the earlobes free of protective clothing or to cut a hole in the rear of the jacket in order to “feel” when temperatures became too extreme.
The efficiency of garments in insulating against external heat allows fire-fighters to spend greater time exposed to hazardous fire ground conditions. For example, better protective gear allows greater confidence in undertaking internal rescue work and fire suppression activity, and in turn, can allow greater time on site involved in the activity. Exposure times can increase and, in turn, heat stress may also become more apparent.
Evolving technology has brought advances in bunker gear which allows greater care of fire-fighters. For example, U.S. Pat. Nos. 5,635,909 and 5,973,602 disclose a system for temperature monitoring which may be incorporated into fire-fighting gear. One example of gear in which the system may be used includes turnout jackets or bunker coats. Cole also discloses that this system may be added to other fire equipment such as SCBA.
However, even with such advances, improvements are possible. For example, it is desirable to determine the ambient temperature at the body surface. Further, there is a need for visually displaying the sensed temperature, both from the exterior and interior surfaces of the gear at one location on the exterior surface of the gear.
As a result there is a need for further improvements in prior developments of this technology.
In accordance with one aspect of the invention, there is provided a thermally insulative garment having an outer shell layer with an exterior side and an interior side, an inner thermal layer with an exterior side and an interior side, and a thermal detector system comprising at least two sensors, the first sensor positioned on the outer shell exterior side and the second sensor positioned on the inner thermal layer interior side, wherein the first and second sensors monitor variance in temperature and signal temperature change.
In accordance with a further aspect of the invention, there is provided a fire-fighter turnout coat comprising an outer flame retardant shell, an inner thermal insulating layer, and a thermal detector system comprising a first sensor positioned on the outer shell exterior side, the first sensor comprising a thermistor and a thermocouple, a second sensor positioned on the inner layer interior side and comprising a thermistor, a first display positioned adjacent the first sensor, and a second display positioned remotely from the first sensor, and a power supply.
The claimed invention provides thermally insulative garments of multiple layers having good ventilation and flexibility. The disclosed designs provide the flexibility for extended effective wear and protection in high risk environments such as fire-fighting. The claimed invention comes from recognized concerns that environmental extremes can result in stresses that must be guarded against. For example, with skin temperature, the difference between pain and second degree burns is a mere 54° F. Further, a temperature stressed fire-fighter consumes 30% to 40% more air reducing time on self-controlled breathing apparatus.
The TST-system/invention alerts fire-fighters when thermal stress factors reach critical levels. This system is designed to increase fire-fighters' awareness to the risk for heat stress and provide the security of a visual alert to abnormal/critical temperatures via a flashing L.E.D. array. Two independent heat sensors are required. A sensor located inside the fire-fighter's jacket measures developments in body temperature inside the protective clothing and a sensor located on the rear of the jacket alerts fire-fighters to dangerous external temperature increases behind them before these prohibit their withdrawal.
The disclosed temperature sensing system uses sensors encapsulated in silicone labels to register and alert fire-fighters to critical changes in external and internal garment temperatures. The design of the labels encapsulates sensors and visual displays while also including a conductive ribbon which acts as a “fabric wire” between the labels, the control unit and control circuits.
The invention includes an inner micro-electronic temperature sensor preferably placed inside the jacket together with the control unit. The sensor and control unit are connected to a display panel sewn onto the sleeve of the jacket and an external beat sensor preferably sewn onto the shoulder and which registers critical increases in ambient temperature. This sensor also has a display diode that is visible so that it may be seen by the wearer's partner. The external sensor is connected to the display on the sleeve and the battery box by a conductive textile ribbon which enables critical temperature increases to be displayed by means such as a light emitting diode.
The overall principle for temperature sensing with the thermal detector system of the invention is based on communication between the sensors, control unit and displays. The various functions of the system have different addresses and are all controlled by circuitry in the control unit. In principle, the control unit transmits different functions concerning status and compares the response with a predetermined program. The temperatures inside the turnout coat, for example, are measured by the inside temperature sensor and transmitted to the integrated circuit which determines whether the measured temperature lies within defined limits. If the measured temperature lies within the limits defined as safe, no further response is made. If the temperature measured by the sensor lies above a first or second limit, defined as unsafe, for example, the integrated circuit within the control unit communicates to the displays and the appropriate visual signal is sent. The sensing principle is based on the actual temperature inside the coat since the temperature deviation is expected to be relatively slow and low.
The temperature outside the fire-fighter's turnout coat is measured by the combination of external temperature, by for example, thermocouple, located in the shoulder label and by circuit board temperature sensor, for example, a thermistor, in the same label. The thermistor in the circuit board registers the exact temperature, and the thermocouple expresses a relative temperature. The external temperature is therefore always the product of both sensor measurements. This principle allows for the thermistor on the circuit board to register whether the circuit board is becoming overheated. The combination of two sensors also allows the operator to determine current external ambient temperature. Further, a sudden increase in difference between the two sensors indicates that the external ambient temperature is rising rapidly. This is a result of insulating the thermistor with the circuit board and exposing the thermocouple by gluing it to a metal plate on the surface of the label.
a is a front elevational view of a fire-fighter bunker coat in accordance with one preferred embodiment of the invention.
b is a rear perspective view showing one embodiment of the invention in its environment of use.
a through 3d are various depictions of the structure, properties and activity of a fabric which may be used as an outer shell layer in accordance with various embodiments of the invention.
a is a plan view of one embodiment of a conductive textile ribbon in accordance with one aspect of the invention.
b is a cutaway axial view of an exemplary conductive fibers used in the conductive textile ribbon depicted in
a is an exploded perspective view of one embodiment of a sensor and signal which may be used in accordance with the invention.
b is a top plan view of the sensor and signal depicted in
a is a further embodiment of a signal display which may be used in accordance with the invention illustrated in exploded perspective view.
b is a top plan view of the signal display depicted in
The invention will now be illustrated through several views wherein like parts are designated by like numerals throughout these several views. One aspect of the invention is a thermally insulative garment such as a fire-fighter's bunker or turnout coat 10,
While the invention may be used in any insulative garment, one principle application is fire-fighting gear. Fire-fighting gear, and in particular jackets 10, are typified by multilayer clothing. Typically, clothing of this type may have two or more layers. These layers may include an outer protective layer 60, an inner thermal insulating layer 70, and an optional intermediate third layer 80, such as a moisture barrier layer. Added intermediate layers may also be used depending on the ultimate application of the garment and the specifications of the user. The outer layer 60,
Synthetic fibers useful to this end include polymeric fibers having a monomeric composition including monomers selected from the group consisting of an ester, an ether, a ketone, an amide, a vinyl alcohol, a tetrafluoroethylene, a vinyl chloride, an imide, a sulfone, an olefin, a benzoxazole, an acetone, an acrylic, an acrylate, an acrylonitrile, an oxide, a sulfide, a phenylene, compounds thereof, compound mixtures thereof, polymers thereof, and polymer mixtures thereof. Commercial materials available for producing the outer shell layer 60 of the jacket include Nomex® Titan™, Nomex® Advance™, and Nomex® Advance Ultra™ all available from DuPont as well as PBI Gemini™ Matrix™, and Basofil® Gladiator™, among others.
In one preferred embodiment of the invention, found at
First and second layers 62 and 64, respectively, are generally connected to make a bilayer through any variety of means,
In accordance with a further aspect of the invention, there is provided an interior thermal layer 70. Generally this thermal layer 70 functions to protect the wearer from temperature conditions external to the jacket 10. The thermal layer 70 may comprise any number of materials including batting, knits, spunlace, woven textiles, nonwoven textiles or any combinations thereof. Here again, Nomex® and Kevlar® fibers may be woven together in a single layer or in combination with fiber selected from those provided above.
Commercial materials useful as thermal layer 70 include ISOMEX® Iso'Air™ available from Duflot.
Further intermediate layers may be included in the garment in accordance with the invention. In one example, a moisture barrier layer 80,
In further detail as can be seen in
A second display 30 may be woven on the external portion of the jacket 10, again as seen in
One principle benefit of the invention is that the first display/sensor 20 is mounted on the exterior surface of the jacket while the second sensor is located in the interior surface of the jacket as part of control circuit 40 and directly adjacent the wearer,
In accordance with one aspect of the invention, garments are provided which have at least two sensors. One sensor is placed on the outside of the garment to measure external ambient temperature. A further sensor is placed on the far interior of the garment, adjacent the wearer. The sensors are interconnected by means such as electrical wiring or radio control. At least three temperatures (absolute and relative) are sensed, the external ambient temperature, the internal ambient temperature, and the difference between internal and external temperatures. These temperatures may be used to activate any number of signals in accordance with the invention. Further, any number of different sensors may be used as one of skill in the art will know having read this specification in accordance with the invention.
Exemplary electronics of the thermal detection system of the invention are further depicted in
Similarly, the second device 30 may be a personal display and generally comprises means for indicating variance in temperature such as one or more light emitting diodes 34. Second signal means may also comprise a thermistor 36 for assisting in sensing heat and communicating these signals and an integrated circuit for purposes of communicating with the control unit 40. Optionally or additionally, device 30 may also comprise a further sensor such as that contained in device 20, for sensing external ambient temperature.
The control unit 40 generally comprises a second temperature sensor and an integrated circuit for communication and translation of temperatures through current flow 42 to the first and second signals, 24 and 34. The control unit 40 also generally comprises a power source such as a battery 43 used to run the thermal detector system of the invention.
Various safeguards may also be placed into the control unit 40 including a self-test as indicated by self-test button 45 and debugging terminals 47 which may be used to program or reprogram the thermal detector system of the invention.
The interconnection 50 shown in
As can be seen in
The control unit 40 as seen in
The control unit 40 may take any number of different configurations or structures consistent with that function. One embodiment of the control unit which is useful in accordance with the invention may be seen in
One embodiment of a combined sensor/display structure 20 is seen in
As is explained further herein, sensor/display 20 preferably comprises two sensors. The first sensor preferably comprises a thermocouple which is directly attached to the metal base of the sensor/display 20. Further, sensor/display 20 also comprises a thermistor which is encapsulated within the circuit board of sensor/display 20. In accordance with the invention, the two different types sensors which are packaged differently on sensor/display 20, result in different sensed temperatures. The difference may be used to prompt alarms as noted below.
A further embodiment of a signal structure or label 30 may be seen in
The LED's may be configured to signal the users through any variety of patterns. For example, the LED's may be configured in series to alert the user together or in parallel to alert the user of separate events such as failing battery life, external temperature stress, or internal temperature stress.
Consistent with the labels shown in
Internal sensor 42,
The thermal sensor system discussed herein may be modeled after any number of electrical systems which allow for two sensors and the positioning of these sensors in a manner which is consistent with the invention.
In accordance with one preferred embodiment of the invention, one scheme of operation for the external thermal sensor system of the invention may be seen in
At an arbitrary time, chosen by the operator or programmer, when the difference between profile 101 and 103 is determined to be too great, an alarm may be triggered at point 104 indicating that the ambient temperature is rising rapidly. A slower increase in temperature may result in a visual alarm at, for example, a higher temperature,
A decrease in ambient temperature (
Overall, this difference in temperature between the two sensors indicates that the ambient temperature is rising rapidly. This comes from insulating the thermistor within the sensor display unit 20 and exposing the thermocouple to at the surface of the unit by gluing it to the heat conductive metal plate of the unit.
The invention may also provide for a second temperature alert (
At the same time that external temperature is being monitored, increase in thermistor temperature (
One further aspect of the invention is the ability to self-test the unit prior to use whether done periodically or prior to the arrival of an incident scene. This can be seen in
Although the present invention has been described in detail by way of illustration and example, it should be understood that a wide range of changes and modifications can be made to the preferred embodiments described above without departing from the scope and spirit of the invention. Thus, the described embodiments are to be considered in all respects only as illustrative and not restrictive, and the scope of the invention is, therefor, indicated by the appended claims rather than the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.