WO1992003833A2 - Capteur de temperature a resistance a couche mince - Google Patents

Capteur de temperature a resistance a couche mince Download PDF

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Publication number
WO1992003833A2
WO1992003833A2 PCT/US1991/005811 US9105811W WO9203833A2 WO 1992003833 A2 WO1992003833 A2 WO 1992003833A2 US 9105811 W US9105811 W US 9105811W WO 9203833 A2 WO9203833 A2 WO 9203833A2
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WO
WIPO (PCT)
Prior art keywords
rtd
thin film
conductive
substrate
temperature
Prior art date
Application number
PCT/US1991/005811
Other languages
English (en)
Other versions
WO1992003833A3 (fr
Inventor
Thomas M. Kiec
Dennis W. Livengood
Arthur P. Haag
Original Assignee
Advanced Temperature Devices, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Advanced Temperature Devices, Inc. filed Critical Advanced Temperature Devices, Inc.
Publication of WO1992003833A2 publication Critical patent/WO1992003833A2/fr
Publication of WO1992003833A3 publication Critical patent/WO1992003833A3/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/24—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of resistance of resistors due to contact with conductor fluid
    • G01F23/246—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of resistance of resistors due to contact with conductor fluid thermal devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D21/00—Measuring or testing not otherwise provided for
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
    • G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
    • G01K7/18—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer
    • G01K7/183—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer characterised by the use of the resistive element
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/04—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having negative temperature coefficient
    • H01C7/041—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having negative temperature coefficient formed as one or more layers or coatings
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/16—Printed circuits incorporating printed electric components, e.g. printed resistor, capacitor, inductor
    • H05K1/167—Printed circuits incorporating printed electric components, e.g. printed resistor, capacitor, inductor incorporating printed resistors

Definitions

  • the present invention relates to thin film resistance temperature devices (RTDs) , and more particularly to thin film RTDs comprising flexible composite.
  • RTDs thin film resistance temperature devices
  • the invention relates particularly to the use of such RTDs in an air flow temperature integrating sensor for use in applications involving dynamic air movement.
  • a resistance temperature device is a device whose resistance varies according to its temperature. By measuring the resistance of a RTD at various temperatures, a Resistance vs. Temperature curve (RT curve) may be obtained for that RTD. Given the resistance of an RTD and its RT curve, the temperature of that device can be computed.
  • alpha (sometimes referred to as the temperature coefficient of resistance (TCR) ) represents the percent unit change in resistance per unit change in temper ⁇ ature (Ohms/Ohm/°C) .
  • TCR temperature coefficient of resistance
  • the TCR at a given point represents the slope of the RT curve at that point. While any device whose resistance varies with temperature may function as an RTD, several desirable features can improve an RTD's performance.
  • the RTD's RT curve be substantially linear over the temperature range to be measured.
  • the TCR corresponds to the slope of the RT curve.
  • the TCR of the RTD should be substantially constant over the desired temperature range.
  • This linearity is desired because, among other thing, it simplifies the development of electronic circuitry to convert the resistance of the RTD into an electrical signal which varies as a function of temperature and it enables the use of linear curve fitting techniques. Further, a repeatable TCR is important for the precise measurement of temperature.
  • a second desirable feature of RTDs is that their RT curves be repeatable. This primarily means that the RT curve for a particular RTD be the same after every temperature cycle excluding burn-in cycles if any (or that the TCR of the RTD be substantially constant over time) . For example, most RTD's physically expand or contract as the temperature changes. This expansion and contraction often causes the RT curve (i.e., the TCR) of a particular device to change over time. Thus, the RT curve of one specific RTD subject to several temperature fluctuations may be substantially different than it originally was.
  • the RTD industry has established certain standards es ⁇ tablishing the acceptable percent variability of the TCR for commercial RTDs; A change in the RT curve is undesirable because, among other things, the electrical circuitry used with the RTD is generally designed to operate with only one RT curve (i.e., one TCR) .
  • the RTD respond rapidly to changes in temperature.
  • certain applications e.g., fire detection, heat detection
  • a desired attribute of an RTD is rapid response to temperature changes.
  • the platinum wire RTD developed by CH. Myers in 1932, has a substantially constant TCR, is able to accurately measure temperature changes, but is fragile and often uneconomical.
  • This device is produced by winding a helical coil of platinum wire on a crossed mica web, and mounting this assembly inside a glass tube. The winding of the wire on the web, the uniformity of wire thickness and the purity of the metal, are necessary for a substan- tially constant and repeatable RT curve (i.e., the TCR is constant) .
  • the coefficient of thermal expansion of the ceramic substrate differs from that of the deposited metal or slurry, which it usually does, substantial changes in the RT curve may occur. These changes are a result of the stress and strain placed on the deposited material when the substrate and the material attempt to expand at different rates.
  • the substrates used in many prior art devices are selected (e.g., ceramics) such that they substantially do not expand or contract at operating temperatures. In dealing with such prior art devices care must be taken to evaluate problems caused by expansion and contraction effects. Further, differential expansion, vibrations, and surface irregularities all affect the theoretical and actual TCRs of ceramic based RTDs.
  • each of these proposed prior art devices appears to utilize a thin (or thick) metal film deposited upon a rigid substrate.
  • the substrate is generally selected such that its expansion is either minimal or matched to that of the metal layer at operating temperatures.
  • RTDs are based on the principle that certain materials exhibit a change in resistance for a change in temperature. In order to allow for accurate measurements of the resistance change, it is generally desirable for the RTD to exhibit a measurable degree of resistance.
  • metal is frequently the material of choice for RTD's. Because most metals are fairly conductive, prior art devices generally follow one of two alternatives: First, prior art devices often utilize metals having a relatively high resistivity for a conductor (e.g., platinum). Metals having low to moderate resistivity (i.e., metals that are highly conductive) such as gold, silver, and aluminum are rarely used.
  • some prior art devices use a metal with low to moderate resistivity (e.g., copper).
  • a metal with low to moderate resistivity e.g., copper
  • typical prior art devices merely use more copper.
  • copper RTDs often have nominal ice points similar to those of platinum, the length of the resistance element is sub ⁇ stantially greater.
  • the devices can be made out of a metal having relatively low to moderate conductivity and comparatively high cost (e.g., platinum); or the devices can be made out of a metal having relatively moderate conductivity and low resistivity (e.g., copper), requiring the use of a longer resistive element and thus the often costly and complex manufacturing processes associated with such lengthy elements.
  • a metal having relatively low to moderate conductivity and comparatively high cost e.g., platinum
  • a metal having relatively moderate conductivity and low resistivity e.g., copper
  • the use of metals of comparatively high conductivity, i.e., of low to moderate resistivity (e.g., gold, silver, aluminum) in RTDs was commonly avoided in the prior art because of the size of the resistive elements that were believed to be necessary.
  • the present invention realizes substantially all of the above-described attributes desirable for a RTD and avoids many prior art difficulties.
  • a polymer thin film RTD can be constructed to be flexible, vibration and impact resis ⁇ tant, to require reduced protective insulation or sheath ⁇ ing, and to have extremely fast response time.
  • the present invention provides an RTD that may be adapted to most all possible RTD applications within operating- temperature limitations.
  • the present invention provides an RTD that has a substantially linear RT curve, has a substantially cons- tant TCR, and is adaptable to operation in multiple envi ⁇ ronments.
  • the invention further provides an RTD with a fast response time which may be easily and economically produced using low cost, highly conductive metals uncommo to RTDs, such as aluminum, silver, and gold.
  • the invention further provides an improved RTD for use in measuring the true average air duct temperatures i heating, ventilation and air conditioning systems.
  • RTD A flexible, low cost, durable, chemical resistant, vibration resistant RTD is disclosed.
  • This RTD includes an polymer-layer/metal-layer composite which exhibits a highly accurate, rapid, and repeatable positive response to temperature changes.
  • the invention involves a thin film RTD and its method of manufacture.
  • a thin film of a conductive material such as metal, especially a gold-chrome composite, is bonded to a substrate such as a sheet comprising a thermoplastic polymer, and a protective barrier such as second sheet of polymer is adhered to the thin film.
  • the composite "sandwich” may then be trimmed or etched into a pattern having terminal ends.
  • This thin film conductor and connector system is calibrated to yield a particular resistance at a known temperature.
  • This calibrated device is a highly accurate, flexible RTD which has a TCR that is substantially constant over changes in time and temperature.
  • the process described herein results in a temperature coefficient of resistance believed to be unique to the polymer/metal composite that is both linear and repeatable over the operating range.
  • the polymer sub- strate is not perfectly smooth and the thin film of con ⁇ ductive material is believed to be affected by the substrate surface characteristics.
  • characteristics i.e., current and resistance
  • an electrical potential across the RTD of the present invention show evidence of properties that are affected by the polymer surface in a manner analogous to the effect of grain in a field on the flow of wind across the field.
  • HVAC heating ventilation and air conditioning
  • the RTD of the present invention can be manufactured in continuous lengths of up to 60 feet. As such, the true average temperature of an air duct may be measured. Further, the device of the present invention is flexible and significantly less subject to damage resulting from vibration, and can be suspended in such a manner as to traverse the entire duct. The savings in energy resulting from the improved temperature readings can be enormous.
  • Figure 1 illustrates a resistive temperature device of the present invention
  • Figures 2A-2B illustrates two methods for applying metal film to a thermoplastic polymer
  • Figure 3 is a chart illustrating a general relationship between resistivity, percent transmission, and optical density for thin film metals in certain circumstances
  • Figure 4 illustrates the application of a protective film to a metallized roll of thermoplastic
  • Figures 5A - 5B illustrate alternate methods of applying the protective film to the metallized roll
  • Figures 6A - 6B illustrate geometric resistive patterns
  • Figure 7 illustrates the heating of a resistive pattern
  • Figure 8A - 8H illustrate various connectors between a thin metal film and an electrical lead
  • Figures 9A - 9C illustrate one method for calibrating the RTD of the present invention
  • FIGS. 10A - IOC illustrate novel devices for temperature measurement
  • Figures 11A - 11C illustrate a novel device for measuring fluid level and fluid temperature
  • FIGS 12-14 illustrate various embodiments of the present invention
  • FIGS 15A-15D illustrate the application of the present invention to heating, ventilation and air conditioning systems.
  • FIG. 1 illustrates a basic embodiment of a resistance temperature detector in accordance with the present invention.
  • An RTD 10 is illustrated as comprising a composite or "sandwich" of three layers.
  • a thin film of a conductive material such as a metal 12 is bonded between a substrate and a barrier such as thermoplastic films 16a and 16b.
  • Electrical leads 14 are connected to the metal film 12 according to one of the methods discussed below.
  • the metal layer 12 may be vacuum metallized aluminum, although silver, gold, lead, copper, platinum, titanium, nickel, molybdenum, tungsten, rhodium, iridium, palladium, doped silicon, tin, zirconium, columbium, alloys including the foregoing, conductive pigments, and foils are believed acceptable.
  • the thickness of the metal layer 12 depends in part on the overall size and characteristics desired for the RTD, but is generally within the range between a mono-atomic layer and about 3000 angstroms (A; lA - 1 X 10 "10 Meters) and frequently between about 25 ⁇ A and about IOOOA.
  • Metal layer 12 may be attached to the thermoplastic sheet 16a via thermal vacuum deposition, although other methods of attachment are envisioned. Currently, sputtering, chemical vapor deposition and the like are believed to be acceptable alternatives for attaching metal layer 12 to thermoplastic sheet 16a. Thermoplastic sheet 16b may be attached to metal layer 12 through the use of known adhesives.
  • thermoplastic sheets 16a and 16b preferably comprise a thermoplastic polymer which is operable in the temperature range to be measured.
  • polyester has been found to be an acceptable polymer for temperatures between -70°C and 150 ⁇ C.
  • Such thin sheets of polyester are t jmmercially available under the trade name MYLAR available from DuPont, or other commercially available equivalents.
  • MYLAR available from DuPont, or other commercially available equivalents.
  • KAPTON and TEFLON are trademarks of the E.I. duPont deNemours company of Wilmington, Delaware; UPILEX is a trademark of ICI Ltd.
  • polymers such as polyethylene, polypropylene, nylon, polycarbonate, poly(4- methyl-1-pentene) , polybutene-1, blended plastics and the like are believed to be acceptable substitutes for MYLAR and KAPTON.
  • the polymers are believed to be acceptable substitutes for MYLAR for lower temperature applications, as well as some higher temperature applications.
  • thermoplastic sheets 16a and 16b it is important to consider the temperature range to be measured, and the polymer's ability to accept metallization. The ability o a thermoplastic polymer to accept metallization is believed to be related to the surface characteristics of the particular polymer.
  • Type A MYLAR has been found to be an acceptable thermoplastic for most applications. (MYLAR is a trademark of the E. I. duPont deNemours company.)
  • the thickness of the thermoplastic sheets 16a and 16 may be determined by the response time and the handling characteristics desired for the RTD. Thicker sheets are envisioned when a slower response time is permissible or desired (i.e., the time required to detect a given absolute temperature rise) , or if increased environmental protection is desired.
  • Electrical leads 14 are connected to metal layer 12 and may be connected to known circuitry to measure the resistance between the leads. By measuring the resistanc between the leads 14 for several temperatures, a characteristic RT curve for the RTD 10 may be obtained. Once the RT curve is obtained, the temperature of the device may be determined by measuring the resistance across leads 14.
  • the first step in making the RTD of the present invention is to determine the composition of the metal layer 12, and of the thermoplastic sheets 16a and 16b.
  • aluminum has been found to be an acceptable metal for layer 12 although other possibilitie are envisioned.
  • Selection of the Thermoplastic Polymer The selection of sheets 16a and 16b involves the consideratio of several factors. First, the thermoplastic film selected should be able to accept metallized films.
  • thermoplastic film selected should be able to operate at the temperatures which the device will be measuring; this includes temperature spikes (temp ⁇ erature "spikes” are short duration rises (or declines) in the temperature) .
  • temperature spikes temp ⁇ erature "spikes” are short duration rises (or declines) in the temperature
  • a film capable of withstanding these temperature spikes should be selected. If the highest possible temperature is not considered in selecting the sheets, the RTD may be destroyed if a temperature spike occurs.
  • MYLAR type A has been found acceptable for most applications at or below 150°C.
  • the particular thickness of the thermoplastic should be selected with the desired response time in mind.
  • the thickness of the thermoplastic sheet is inversely related to the response time of the RTD. Generally, the thicker the thermoplastic sheet, the slower the response time.
  • the needed thickness can be calculated given the desired response time and the thermal conductivity of a given thermoplastic material. This calculation can be accomplished through simple engineering techniques well known in the art. Thicknesses of between 0.5 and 10.0 mils have been found to be acceptable.
  • thermoplastic material 16 For many applications in the lower temperature range requiring comparatively rapid response times. Type A, 300- gauge MYLAR has been found acceptable. Certain polymers are known to emit toxic vapors at high temperatures. Consequently, appropriate precautions may need to be made when selecting the thermoplastic material 16.
  • the selection of the metal material 12 involves many factors. First, as discussed above, it is generally desirable to have a RTD with a linear RT curve. As such, it is generally desir ⁇ able to select a metal having a substantially constant TCR over the expected operating temperatures. Second, for economy reasons, the cost of the material and its strategic availability may be considered. The coef- ficients of thermal expansion (TCE) for the metal and the thermoplastic material should also be considered. Gen ⁇ erally it is desirable to have the coefficients of thermal expansion of the metal and the thermoplastic sufficiently close to avoid problems from strain such as altered temperature coefficients of resistance.
  • a film of aluminum having a TCE of about 26 microinches per inches per degree Celsius, 26 ⁇ in/in/°C
  • a substrate of MYLAR having a TCE of about 17 ⁇ in/in/°C
  • Other considerations should be: (1) the thickness of the conductive film and the current load, (2) possible Seebeck effects arising from use of dissimilar metals at an interconnect, (3) the temperature range at which the device will operate, and (4) the strain gage factor of the metal — it is believed advantageous to select metals that have a strain gauge factor close to zero.
  • Vacuum Deposition When the metal 12 and the thermoplastic material 16 have been selected, metal 12 ma be vacuum deposited on a first roll or individual sheet o thermoplastic material 16. Vacuum deposition procedures ar. well known in the art and will not be discussed herei in great detail.
  • Figure 2 show a vacuum deposition chamber 20. A roll of the selected thermoplastic polymer 26 is positioned within the chamber. The selected metal 28 is then deposited onto the sheet 26.
  • the size of roll 26 depends on the application for which the RTD is being manufactured. For example, for small RTD's a roll width of 1 inch will suffice; for larger RTDs, sizes up to the standard 60-inch roll may be necessary. Generally any roll size may be used because the size of the roll is not believed to affect the performance of this invention except for variability related to the uniformity and consistency of the deposition.
  • the deposition thickness of the metal is an important feature of this invention.
  • the metal 28 should be deposited on the sheet until its depth is in the desired range.
  • the depth of the deposition plays an important role in allowing the RTD of the present invention to yield a repeatable and substantially linear RT curve.
  • the RTD of the present invention exhibits a substantially linear RTD curve that is not believed to be significantly affected or degraded by numerous temperature cycles over an expected operating range after an appropriate burn-in period. This is believed to be a result of a special interaction between the deposited metal and the resin surface of the thermoplastic polymer. This special interaction between the metal and the polymer is believed to be closely re ⁇ lated to the deposition thickness of the metal. For example, when aluminum deposition depths of greater than about 300 ⁇ A are used, it is believed that the effects of the metal layer 12 dominate those of the thermoplastic sheets 16a and 16b. As such, any RTD produced in such a process would exhibit substantially the same qualities as a metal film on a substrate other than the polymer.
  • the region approximately between 25 ⁇ A - lOOoA allows the RTD to exhibit several unique characteristics, i.e., substantial linearity and repeatability.
  • the mechanisms causing the linear RT curve and the high repeatability for this region are not yet fully understood but are believed to involve the interaction of the thin metal layer and the relatively rough surface of the thermoplastic sheet.
  • thermoplastic sheet has been found by the inventors to be slightly higher tha would be expected. This is believed to be result from th coarseness of the thermoplastic film, having small, micro scopic peaks and valleys, imparting a uniform reduction in the electron flow of the thin film deposited metal. This reduction on electron flow is believed to result from the interferences of the non-conducting resin of which the thermoplastic is made with the continuity of the metallic deposit.
  • the effect of this interaction may be labeled the "cornfield effect" as the resistance provided by the roughness of the resin surface may be likened to the resistance to air flow that exists over a cornfield as opposed to a flat open area.
  • FIG. 3 sets forth a chart illustrating three variables that may be assigned to a sheet that has received a metal deposition (a metallized film) .
  • the chart shows that for aluminum, the optical density, percent transmission and sheet resistance (ohms per square unit of area) may be used to describe any given metallized film. This chart is merely representative of several available in the prior art.
  • resistivity percent transmission, and optical density
  • the sheet resistance has been found acceptable, although the other variables may be used.
  • Depositions to yield resistivity between about 0.5 ohms/square to about 1.5 ohms/square are believed to be satisfactory; with a sheet resistance of 1 ohm/square being preferred.
  • Aluminum deposition thicknesses between approximately 250A - 300 ⁇ A are also believed to be satisfactory. Techniques for depositing a metal on a thermoplastic film given a desired sheet resistance (ohms/square) are well known in the art and will not be discussed here.
  • Vacuum deposition is not the only way that the metal can be attached to the thermoplastic material.
  • Other techniques such as metallization, lamination, pressure sensitization, thermal curing, printing, electrodeposition techniques, chemical vapor deposition, vacuum deposition, sputtering, glow discharge, radiation curing (e.g., ultraviolet curing) , printing techniques, plasma deposition, thermal evaporation, E-beam evaporation, and the like are believe to be viable. What is important when using alternate techniques is that, for aluminum, the layer of metal have a thickness generally within the above described limit, i.e., approximately 25 ⁇ A - lOOoA. H. Gold/Chrome Embodiments of the RTD
  • thermoplastic material Prior to the application of the metal to the thermoplastic material, a coating or coatings to reduce the effects of heat aging may be applied to the thermoplastic. Additionally, it has been found beneficial to deposit more than one type of metal 12 on the thermoplastic polymer.
  • Figure 2B illustrates such a device.
  • a thin layer of chrome 12a (approximately lOoA to 15 ⁇ A) is deposited on the polymer sheet 26 using known methods.
  • a glow discharge is used prior to the chrome deposition to both improve the adhesive qualities of the polymer sheet and remove contaminates.
  • a slightly thicker layer of gold 12b (approximately lOOoA) is deposited on the chrome.
  • the gold/chrome device may be processed according to the methods discussed below in regard to aluminum devices. This embodiment has been found to have several advantages over the aluminum device (e.g., the gold/chrome device is better adapted for harsh environments) .
  • the chrome layer serves primarily to promote adherence of the gold film. Because the sheet resistance of chrome in this thickness is substantially greater than that of thin film gold, the sheet resistance of the gold/chrome layer RTD is substantially the same as that of a gold layer RTD.
  • a second roll 46 is applied as a protective cover. This process is illustrated in Figure 4. This top laminate is for the protection of the conductive surface and is not believed to enter into the electrical process.
  • a second roll 46 is provided.
  • This second roll 46 may be made of the same thermoplastic material as the first roll 26. Further, the second roll 46 may have an adhesive precoated on one side. For operating ranges at or below 125°C, the V-95 adhesive from the Flexcon company (near Boston) has been found to be acceptable, although with sustained use at higher temperatures, potential problems may arise due to heat aging and possible interactions between the adhesive and the film.
  • the adhesive When the adhesive is precoated on the second roll 46, it may be attached to the first via pressure from rollers 40 and 42. This second roll of thermoplastic is useful to protect the metal layer from scratching, erosion and corrosion.
  • the second roll of thermoplastic does not cover all of the metallized surface of the first roll. These embodiments are illustrated in Figure 5A - 5C As Figure 5A shows, the second roll 46 may cover all but the edges of the metallized surface of the first roll 26. The exposed region 50 may be used to make connections to the metal layer to allow for the attachments of electrical leads 14 as illustrated in Figure 1.
  • the second layer of thermoplastic 46 covers all but two strips of the metallized surface of the first roll 26.
  • the two exposed surfaces are labeled as 52.
  • the exposed surfaces may be used to make connections to the metallized surface of roll 26.
  • the geometry of the second, protective layer may be of any shape, it is generally beneficial to leave regions close to the center of the roll exposed for connections. The reason for this is that vacuum deposition, while creating an essentially uniform surface, tends to deposit a more uniform layer of metal at the center of the roll. Further, the thickness of the metal at the center is sometimes greater than that at the edges. This slight difference in thickness and uniformity becomes significant when deposition thicknesses in the region of this invention are used.
  • the second roll of ther ⁇ moplastic is not applied to the metallized first sheet roll.
  • the metal may be left unprotected, or a protective coating or coatings, such as silicon monoxide or other standard barrier coatings, may be adhered to the surface.
  • the well-known ADCOTE 554 from the Morton-Thiokol company has been found to be an ade- quate barrier coat. It has been found advantageous to thin the ADCOTE with methyl ethyl ketone (MEK) for application to exposed metal surfaces. Methods for coating such metal layers, e.g., painting, spraying, are known in the art and will not be discussed herein. As discussed above, it may be desirable to leave regions close to the center of the roll uncoated for the purposes of making electrical connections.
  • ADCOTE a two step heat treatment has been found to be adequate; e.g., heating the coated RTD to 35 °C for fifteen minutes, and then heating the RTD to 50 °C for an additional fifteen minutes.
  • the metal/thermoplastic composite "sandwich” is cut into a desired resistance pattern.
  • a portion of the composite e.g., the outer portions of the rolled thermoplastic sheet
  • each such shape is physically trimmed o otherwise treated to increase its resistance as desired t meet a specified standard.
  • photoprocessing e.g., a photo-etch
  • photoprocessing is employed to obtained the desired resistor pattern before the second, protective roll is affixed to the metallized first roll.
  • thermoplastic film Methods for cutting a thermoplastic film are generally known in the art. For example, for large RTDs (e.g., a 60" or 12" roll) die cutting or other blade cutting may be used; for smaller rolls (e.g., 1") laser cutting or water jet cutting may be used. Such technique are known and will not be discussed herein. Generally, any method of cutting that does not destroy the main body of the thermoplastic (e.g., by elevating the temperature of the sandwich to greater than that allowed for the thermoplastic film) may be used.
  • Resistive patterns for thin and thick films are known in the art and will not be discussed in detail. These patterns may include rectangles, circles, other basic geometric shapes, and serpentine patterns. Examples of such patterns are the well known bar, top-hat, loop, and ladder patterns. Figures 6A and 6b are provided as examples of such patterns. In Figure 6A a square spiral pattern 60 is shown, while a rectangular pattern 62 is illustrated in Figure 6B.
  • the resistance of the RTD is proportional to the aspect ratio, or number of squares, between the two terminal points.
  • the number of squares in a resistor is calculated using the length of the conduc- tive path divided by its width factoring in corrections for contacts, bends, and changes in shape.
  • a calibration strip 64 may be provided. As discussed below this calibration strip may be used to "fine tune” or calibrate the RTD to a desired resistance at a certain temperature.
  • One desirable resistance is 1000 ⁇ .5, 1, o 2 ohms at 0°C
  • the material comprising the RTD is flexible. This allows the resistiv patterns to be cut to virtually any geometry and to be customized to specific applications in a cost effective manner. For example, a spiral-square or other pattern ma allow the resistive element to conform to the shape of a particular object, e.g. , an air duct. Resistive patterns may be designed and customized to meet the requirements o any number of specific applications.
  • the present invention allows for the manufacture of sensors having identical base resistances (e.g., 100 ohms at 0°C) but very different dimensions.
  • RTD of dimension 5/8" X 2-1/4" can have the same base resistance (e.g., 1000 ohms at 0°C) as RTDs of dimension 1/2" X 24 feet, 1/4" X 48 feet, and 12" X 5/8". This attribute while not unique to the present invention, is considerably easier than with either current ceramic base RTDs or wire-wound technology.
  • the resistive patterns After being cut from the thermoplastic/metal sandwich, the resistive patterns are then heated to a temperature slightly above the expected operating temp- erature (e.g., approximately 155°C for MYLAR) and left at this temperature for a short period of time (approximatel 30 ⁇ 5 minutes) .
  • Vendor process recommendations for heat- stabilizing MYLAR indicate that a temperature 30°C above the expected maximum operating temperature is beneficial. This process is illustrated in Figure 7.
  • two metal plates 70, 72 may be used during this heating, or annealing, to compress the resistive patterns and prevent these patterns from distorting. This annealing step is sometimes necessary to improve the dimensional stability of the RTD over temperature cycles.
  • the devices should not be calibrated until after the completion of the heat treatment step. It may be possible to omit this annealing step if heat-stabilized materials are used.
  • the temperature and length for the heat treatment step may be adjusted depending on the prior or subsequent heat treatment to which the RTD has been or will be subject to (e.g., overcoat curing steps). Care should be taken to ensure that the temperature and time of the heat treatment step are acceptable for the selected laminate adhesive.
  • the temperature at which the heat treatment step is performed may affect the TCR of the resulting RTD. Basically, the higher the temperature during the heat treatment step, the higher the TCR.
  • FIGS 8A - 8E Alternate methods for affixing the connectors to the resistive patterns are shown in Figures 8A - 8E. 1. Conventional Connector Attachment. As Figure 8 illustrates, connections to the resistive pattern may be made by a conventional crimp connector 80, such as those currently available from the AMP company of Harrisburg, Pennsylvania. These connectors, much like staples, may b affixed to the terminal ends of the resistive pattern as shown.
  • the metal layer is extremely thin, it is often difficult to make a good electrical connection to the connector. Further, the combined metal and therm ⁇ oplastic layer thickness is so thin that the connector ma not be able to "grab" enough of the resistive element to hold the device.
  • One possible method of overcoming this problem is to add a backing 82 to the terminal ends of th resistive elements 60. An additional backing of approximately 5 to 7 mils has been found sufficient for purposes of making the connector attachment.
  • a layer of conductive epoxy 84 may be applied to the exposed metal surface of the resistive element.
  • This exposed surface provides a larger area ove which electrical contact may be made, and addresses the additional concern, related to a finely divided reactive thin film, that when the thin film is disintegrated, it oxidizes very readily because of the high surface area.
  • Figure 8b These alternatives are illustrated in Figure 8b with the conductive epoxy illustrated on top of the exposed region of sheet, and the backup illustrated directly underneath.
  • an electrical connector may be attached to the resistive element without the use of a backing element.
  • a layer of conductive " epoxy 84 is applied directly to a portion of the resistive element.
  • a silver-based or nickel-based epoxy has been found adequate for this pur ⁇ pose.
  • a plate of copper or nickel may be attached to the resistive element.
  • the gold/chrome embodiment it is helpful to use only a nickel plate or to have a thin nickel plate separating the gold layer and the copper plate.
  • the precise thickness of the epoxy layer 84 or the plate is believed not to be critical so long as the material thickness specifications for use of the AMP connectors are met, but it is beneficial if the epoxy or plate covers the entire underside of the AMP connector.
  • a connector of the type illustrated in Figure 8A may be attached using known methods.
  • a protective barrier coat may be applied to the resistive element/con ⁇ nector combination or a protective resin may be applied to the exposed surfaces and edges.
  • FIG. 8C - 8E A second method for attaching a connector to the resistive pattern is illustrated in Figures 8C - 8E.
  • an interconnect board should first be selected that can meet the temperature extremes established for the RTD (e.g., a board comprising an injected molded or molded polymer resin) .
  • the interconnect board may be matched to the thermoplastic material used in the RTD (i.e., may be made of the same material) .
  • Such a board is illustrated as 86 in Figure 8C.
  • This board is then patterned, or etched to a pattern, of approximately 4 mils.
  • Several conductive traces 88 are then attached to the board via conventional plating techniques or adhesion. The number of traces depends on the number of connections to be made to the RTD. Electrical leads 90 are attached to the conductive traces or strips.
  • the molded 3-D interconnects generally include one or more conductive strips 88', usually copper with a top plate of nickel, an insulating base 86', and electrical leads 90'. The following discussion applies to both the prepared PC board and the 3-D molded interconnect.
  • thermoplastic polymer 92 is attached to the base of the connector via adhesive or mechanical rivets. This sheet should be attached to the base 86 such that the conductive strip 88 and the thermo ⁇ plastic sheet 92 form a substantially planer interconnect surface 94.
  • the thermoplastic sheet 92 with the connecto attached is then placed into a vacuum deposition chamber or the like and a highly conductive film is deposited at the junction between the copper/nickel conductor 88 and the thermoplastic sheet 92.
  • the thickness of the conductive film is not critical so long as the conductivity is high compared to the sheet resistance of the RTD material and it meets the mechanical requirements of he device (e.g., no cracking over the edges). Shadow mask tooling or photolithography may be used to ensure that the conductive material is applied to or remaining o only the junction region. Because different materials all come together at the junction region, and that region may be thermally cycled, it is useful to ensure that a conductive path always exists across the junction region.
  • the highly conductive film 96 provides such a conductive path.
  • the connector- thermoplastic sheet provides a planerized interconnect area with the leads already connected.
  • the shadow mask is removed (if shadow mask tooling is used) and a sputter etch may be performed to remove any oxides or other contaminates.
  • the thermoplastic sheet with the connector may be placed into a vacuum deposition chamber, and a thin layer of metal 96 (approx. 25 ⁇ A - lOOoA) may be deposited onto it as discussed above.
  • a protective coat e.g., silicon dioxide
  • Such a protective coat may inhibit the oxidation of metal layer 96.
  • the use of a protective coat may be especially helpful when the metal layer 96 comprises a reactive metal.
  • thermoplastic 98 may be applied to the metallized sheet and the resistive patterns may be cut out.
  • the connectors are attached to the first ther ⁇ moplastic sheet throughout the process.
  • the exposed metal region is left exposed after the connector is attached. This may leave the exposed region vulnerable to corrosion, erosion, or scratching. To inhibit such damage, a barrier coat may be applied to the exposed surface after the connector is attached.
  • FIG 8G A further method of attaching a connector to the resistive pattern is illustrated in Figure 8G.
  • crimp connectors of the type illustrate in Figure 8A were originally designed to be attached to interconnects having thicknesses much greater than that of the resistive element of the present invention. As such, it is often difficult to make good electrical connections between the present resistive element and traditional crimp connectors.
  • thermoplastic polymer having a minimal thickness (approximately 3 mils thick) throughout most of the area, but gradually increa ⁇ sing to a thickness on one end 93 sufficient to accommod ⁇ ate most traditional crimp connectors (approximately 10 mils).
  • a substrate is illustrated as 92' in Fig ⁇ ure 8G.
  • resistive elements are formed according to the steps disclosed above. Once the processing steps are completed a crimp connector may be attached to the thick end 93 of substrate 92' using known methods.
  • FIG. 8H A still further method for attaching a connector to resistive patten is illustrated in Figure 8H.
  • a layer of flexible polymer 92 is attached to a molded interconnect 86" using an adhesive suitable for the temperature range to which the resistive element will be subjected to.
  • Interconnect 86" is similar to that described above in regard to Figure 8D except the interconnect of this embodiment has a planer interconnect surface. It is generally desirable that the layer of polymer 92 fully cover the plated surface of the interconnect 86". Once the adhesive has cured, vias 95 are manufactured through the adhesive and the polymer layer 92 down to the surface of the plated leads of interconnect 86.
  • the vias 92 can be produced using mechanical methods, e.g., drilling, or through chemical methods, e.g., photolithography techniques and wet or dry etching. After producing the vias, the conductive material 12 is deposited over the polymer and the resistive elements are produced as disclosed above.
  • One factor in ensuring good coverage of the vias is the slope of the vias down to the plated surface.
  • the particular slope selected depends on the step height, the dimension of the deposition source, and the source to substrate distance. Calculations to determine the maximum permissible slope angle are known and will not be discussed herein.
  • thermoplastic can be applied to the resistive patten to completely cover both sides of the patterns to prevent erosion. This process is known in the art as overlaminating and will not be described in detail. 4. Applying an Overmold to the RTD. After the overlaminate and/or recoat has been applied to the RTD, it may be desirable to provide an overmold to the portion of the RTD where the connector is affixed to the resistive pattern. This overmold may be either a small plastic or an ejected rubber shell. The overmold may be used to both isolate the exposed thin film and electrical connector from the environment and to provide strain relief on the connector/RTD interface by limiting the bend radius at the interface.
  • the resistive elements may be calibrated. Calibration may be necessary because of the percent variation that is inherent is several of the previous processing steps.
  • the resistive patterns calibrated such that the resistance is defined a 0°C (e.g., 100 ohms at 0°C, 250 ohms at 0°C, 500 ohms at 0°C, 1000 ohms at 0°C) . Because the RT curve of the RTD of this invention may be determined, it is possible to calibrate the devices at temperatures other than 0°C.
  • Known iterative techniques using a calibration bath may b employed (i.e., calibrate in a bath; trim; calibrate again; trim again; and so forth) .
  • FIG. 9A - 9B illustrate another calibration technique.
  • a table having a glass top 100 is provided with a connection strip 102 attached to a personal computer 104. Alternatively, a comparator board may be used in place of personal computer 104.
  • the connection strip 102 contains several leads 103 that may be attached to the electrical leads of the RTD's to be calibrated. Within the connection strip 102 is provided a RTD 106 tha has already been calibrated.
  • a heater 108 is provided to heat the glass top 100 to approximately 100°F. The glass top 100 table is heated so that the RTDs to be calibrated and the pre-calibrated standard are at substantially the same temperature.
  • a switch on the connection strip 110 allows the operator performing the calibration to select which of the uncalibrated RTDs is to be measured.
  • the personal computer 104 is attached to conventional circuity which measures the resistive value of the uncalibrated RTD 112 and that of the calibrated RTD 106.
  • a visual indication is provided to indicate the difference between the two devices.
  • a calibration strip 114 may be designed into the RTD. This calibration strip 114 is illustrated in Figure 9B. As discussed above, the resistive value of the RTD depends on the area (in number of squares) that is between the terminal points of the resistive element. By carefully cutting along the slit 116, the number of squares between point A and point B may be increased.
  • FIG 9B1 the area between point A and point B is about 1 square unit of area. After extending the slit to point X, there are four square units between the points. This is illustrated in Figure 9B2.
  • the above describe calibration method may be followed to increase the resistive value to precisely the right amount.
  • One method for extending the slit 116 is illustrated in Figure 9C. In this method a slotted cover 120 is provided that may be used to cover the resistive element being calibrated. A cutting razor 122 is then inserted through the slot. The slotted cover 120 is necessary to prevent the heat from the individual performing the calibration from affecting the temperature of the device being calibrated.
  • an ice bath 124 may be provided for use as a reference standard. The use of an ice bath in calibrating RTDs is discussed in ASTM Publication No. E-644.
  • a layer of a barrier coating (e.g., ADCOTE) may be applied to the area of the RTD trimmed during calibration for protection.
  • the resistance of the RTD may be measured using known electronic devices. These electroni -35-
  • devices may be configured to produce an industry standard 4-20 milliamp output using the RTD of the present invention.
  • the RTD of the present invention has several applications.
  • One application facilitated by the present invention is that of large scale temperature integration.
  • Temperature integration involves the determination of the integrated temperature of a large single object (e.g., a large wall) , or of a particular region of material (e.g. , water flowing through a pipe) .
  • the integrated temperature of such objects or regions is often useful for making engineering decisions, for process control, and for basic temperature detection.
  • large scale temperature integration has often been done through the use of numerous temperature sensors whose outputs had to be averaged by other expensive and complex apparatus.
  • FIG 10A illustrates one method of using the present invention to measure the integrated tempera ⁇ ture of a large wall.
  • a large RTD 130 is manufactured and affixed to the wall 132.
  • This large RTD 130 may be adhered to the wall (if the measurements are to be permanently taken) , or held in place by non-permanent connectors (e.g., tape, tacks, etc.). Because a single RTD (or multiple RTD's connected in series) covers the entire wall, and because of the quick response time of the present invention, the RTD will quickly yield an indication of the integrated wall temperature.
  • the RTD 130 can, because it is flexible, be rolled into a compact package once the wall temperature is measured. Further, because of the flexible nature of the device, a "RTD shell" can be produced which could essentially conform to the shape of the object whose integrated temperature is desired to be determined.
  • RTDs of the type shown in Figure 10a may be embedded within a wall, airplane wings, or other objects to constantly measure the average temperature of those devices.
  • Figure 10B illustrates a portion of pipe that can measure the integrated temperature of the fluid flowing therethrough.
  • a long, rectangular, RTD 134 is coiled and affixed to the inside of the pipe 136.
  • the new re- sistance can be measured, and the integrated temperature of the fluid may thereby be determined with reasonable accuracy and precision. In this manner the temperature of large fluid containers, such as the storage areas of shipping tankers, may be measured.
  • FIG. IOC A still further embodiment of the present invention is illustrated in Figure IOC.
  • a flexible RTD 140 of the present invention is designed and patterne so as to conform to the shape of a particular motor 142.
  • the thermoplastic sheets used in manufacturing the RTD 140 comprise so-called shrink wrap material, and the RTD 140 is "shrink-wrapped" (e.g., thermally conformed) around th motor 142.
  • This particular embodiment allows the heat of the motor to be effectively monitored during operation. quick rise in temperature or a gradual rise to a high temperature could provide a fast indication of improper motor operation.
  • Figures 11A and 11B illustrate a novel fluid level and temperature measuring device that is made possible by the present invention.
  • Figure lla illustrates one embodiment of this device.
  • a first RTD 150 is applied along the walls of a large fluid container, e.g. , the cargo area of a shipping vessel. As discussed above, this RTD may be used to measure the integrated temperature of the walls of the container. Although illustrated as covering only one wall, the RTD may be designed to cover substantially all of the container.
  • RTDs 152 are positioned so as to run horizontally along the wall. These RTDs 152 are used to determine the level of the fluid in the container.
  • the thermal conductivity of a substance in fluid form is much greater than the thermal conductivity of that same substance in gaseous form.
  • the temperature of thermally conductive materials in contact with the fluid will change at a rate substantially different from materi ⁇ als in contact with the gas.
  • the invention of Figure lla makes use of the difference in conductivity to determine the fluid level in the container.
  • RTDs 152a and 152b consistently monitc- the temperature of the walls of the container.
  • RTD 152a will provide an indication as to the general temperature " of the gas/wall interface;
  • RTD 152b provides an indication as to the temperature of the fluid/wall interface.
  • the gas/wall temperature Tg may be measured, while RTD 152b yields the fluid/wall temperature Tf.
  • RTD 155 of known length L, is positioned vertically in the container such that its length runs from the botto of the container to the top. From the resistance of RTD 155, the temperature measured by that device may be cal ⁇ culated. This advantageously permits rapid, integrated measurement of differential heat transfer rates between the liquid and gas.
  • the level of the flui may be determined by a ratio of the resistance values.
  • a heating element is provided to add heat to the system for brief periods of time. During the time the heating element is activated, the change in the temperature of each RTD can be measured and compared as discussed above.
  • FIG 11B illustrates an alternate embodiment of fluid level and temperature device.
  • a single RTD 155 is positioned vertically in a container 160 which is capable of receiving fluid 162.
  • the RTD 155 should first be calibrated. This is done by measuring the RTD's 155 resistance when the container 160 is empty, i.e., R 0 , and when the container 160 is filled with the fluid to be monitored at a known level KL, i.e., R 1 .
  • KL i.e., R 1
  • the propor ⁇ tional relationship between resistance measured to fluid level can be calculated.
  • a basic method for performing such a calculation is to compute the quantity L ? KL/(R x
  • the level of the fluid may be measured by taking the resistance value that is measured, and multiplying it by the proportionality constant determined when the device was calibrated.
  • FIG. 11B An alternate embodiment to the device of Figure 11B is illustrated in Figure lie. This device operates similar to that describe above in respect to Figure 11B, but the RTD 155 covers several sides of the container.
  • FIG. 12 A still further embodiment of the present invention is shown in Figure 12.
  • a web of RTDs 160 is shown.
  • Web 160 comprises vertical strips 161, as well as horizontal strips 162.
  • By monitoring the temperatures of all of the RTD's it may be possible to pinpoint the location of a rise (or fall) in temperature. For example, if a temperature rise occurs at point X, both RTD 161' and 162' will show a rise in temperature.
  • the precise location of a temperature disturbance may be located.
  • Such information may be particularity important when the location of a dangerous temperature disturbance needs to be known.
  • FIG. 13 A still further embodiment of the invention is illustrated in Figure 13.
  • a multilayer RTD 170 is shown.
  • RTD 170 comprises several RTD's, 171, 172 of the type discussed above.
  • a thin metallic film 173 is also provided.
  • the RTDs 171 and 172 should be selected such that the thermoplastic material of the RTD 171 will break down at a lower temperature than that of the RTD 172.
  • RTDs By having RTDs"171, 172 of different temperature ranges, a sensor is created whereby the degree of a temperature disturbance may be monitored and determined. For example, a rise in temperature up to a certain level may cause RTD 171 to break (e.g., separate). Such a brea would yield an infinite resistance for that RTD. This could set off one alarm indicating that some action shoul be taken (e.g., RTD 172 should be closely monitored.)
  • RTD 172 Because the temperature range of RTD 172 is greater than that of RTD 171, the temperature of the system being monitored can still be measured. Then, by progressively stacking RTDs of different temperature ranges, a sensor may be produced whereby various alarm signals are provide depending on the degree of temperature rise.
  • Conductive film 173 is provided so that a complete break of the RTD may be measured. For example, a break o all the RTD's as well as film 173 may indicate that the sensor has been inadvertently severed as opposed to act ⁇ ually destroyed by a temperature disturbance.
  • FIG. 14 A still further embodiment of the present invention is illustrated in Figure 14.
  • the RTD of the present invention is combined with a pressure sensor to yield a unitary pressure/temperature sensor.
  • First an RTD 180 of the present invention is affixed to a thermoplastic protective layer, or a base support layer 181. If YAG laser processing is employed (or its equivalent) , the base support layer 181 may be the substrate of RTD 180.
  • a partial grid is then constructed on the base support layer using parallel lines 183 of conductive ink. These lines may be applied to base 181 through known met ods.
  • the base support layer 181, including the conducti lines, is then coated with a conductive elastomer 182 su as a polyvinylidene fluoride polymer (PVDF) , a piezo ⁇ electric material.
  • PVDF polyvinylidene fluoride polymer
  • a second group of conductive lines 18 is then applied to the piezomaterial coating 182. Electrical leads 187 may then be attached to the conductive lines.
  • material 182 comprises a resistive conductor material.
  • the grid lines 183, 185 may be used or the resistance of the coating 182 itself may be measured.
  • a force applied to the coating of this embodiment increases the contact area between two lines. This results in a decrease of resistance between the lines.
  • the applied force can be determined.
  • the RTD of the present invention may be constructed in such a manner to allow its suspension in an air duct so that it may be exposed to the total air flow through the duct.
  • the RTDs of the present invention function as temperature integrating sensors (TIS) .
  • TIS temperature integrating sensors
  • a single TIS is advantageous over numerous RTDs because it measures the true average (integrated) temperature rather than an approximate average obtained from a few discrete temperature measurements.
  • a sensor 200 comprising a flexible RTD 202 is sandwiched between two polyester layers 204a and 204b. Although only one RTD 202 is illustrated, several different RTD's may be sandwiched between the polyester layers 204a and 204b.
  • polyester tabs 206 are attached t the sensor 200 at six inch intervals.
  • the tabs 206 preferably protrude 1" to 2" above the sensor and are use to suspend the sensor in the air duct.
  • Figure 15B illustrates one way in which the sensor of 15A may be suspended in a air duct.
  • An alternative to using tab 206 is illustrated in Figure 15C.
  • a pressure sensitive adhesive is applied to the backside of sensor 200. The sensor 200 is then either attached to an interior wall 208 of the air duct or attached to a piece of interior tubing 210 used to traverse the duct.
  • Figure 15D illustrates one embodiment in which a rectangular base 212 is used to support the sensor in the air duct.
  • An advantage of the sensor of the present invention is its ability to bend, fold, or wrap inside the air duct This feature allows the sensor to measure the temperature of flowing air (which may stratify, form eddy currents) , dead zones, or areas of laminar flow, without being undul influenced by the temperature of ambient air and/or the wall of the air duct.
  • an entire zone of air duct may be monitored. For example, using the methods described above an air duct temperature integrating senso of 60 feet in length may be produced.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Thermal Sciences (AREA)
  • Fluid Mechanics (AREA)
  • Electromagnetism (AREA)
  • Measuring Temperature Or Quantity Of Heat (AREA)
  • Thermistors And Varistors (AREA)
  • Laminated Bodies (AREA)

Abstract

Capteur intégrateur de température pour un conduit d'air dans un système de chauffage/ventilation/climatisation (HVAC), ou tout autre conduit de circulation de fluides, comprenant un capteur de température à résistance flexible (RTD) que l'on fabrique par dépôt d'une mince couche de chrome et d'une deuxième couche mince d'or sur un mince support thermoplastique flexible.
PCT/US1991/005811 1990-08-15 1991-08-15 Capteur de temperature a resistance a couche mince WO1992003833A2 (fr)

Applications Claiming Priority (6)

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US56844590A 1990-08-15 1990-08-15
US568,445 1990-08-15
US66134091A 1991-02-25 1991-02-25
US66133491A 1991-02-25 1991-02-25
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Cited By (10)

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EP0674157A1 (fr) * 1994-03-24 1995-09-27 Volkswagen Aktiengesellschaft Procédé pour détecter au moins une quantité physique
DE19839631C1 (de) * 1998-08-31 2000-03-30 Siemens Matsushita Components Verfahren zum Herstellen eines Temperatursensors
EP1260804A1 (fr) * 2001-05-22 2002-11-27 Siemens Building Technologies AG Dispositif pour former une moyenne pour la mesure d'une température
EP2065903A1 (fr) * 2007-11-29 2009-06-03 Delphi Technologies, Inc. Méthode de réalisation d'un capteur de suie
WO2009083505A1 (fr) * 2007-12-27 2009-07-09 Robert Bosch Gmbh Procédé pour produire un conducteur électrique par application d'au moins une pâte, en particulier une pâte en couche épaisse
EP2290334A1 (fr) * 2009-09-01 2011-03-02 Siemens Plc Sonde de niveau cryogène
EP2953103A1 (fr) * 2014-06-02 2015-12-09 Siemens Schweiz AG Dispositif d'alarme
WO2018190860A1 (fr) * 2017-04-14 2018-10-18 Hewlett-Packard Development Company, L.P. Dispositifs et procédés de détection de caractéristique de fluide analogique
CN114122540A (zh) * 2021-11-15 2022-03-01 电子科技大学 一种温度检测器及其制备方法、锂电池结构组合
EP4040126A4 (fr) * 2019-10-01 2023-10-11 Nitto Denko Corporation Film électroconducteur et son procédé de fabrication, film capteur de température et son procédé de fabrication

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DE2302615A1 (de) * 1973-01-19 1974-08-08 Max Planck Gesellschaft Temperaturabhaengiger elektrischer widerstand fuer eine messonde
US4323875A (en) * 1981-01-21 1982-04-06 Trw, Inc. Method of making temperature sensitive device and device made thereby

Patent Citations (2)

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Publication number Priority date Publication date Assignee Title
DE2302615A1 (de) * 1973-01-19 1974-08-08 Max Planck Gesellschaft Temperaturabhaengiger elektrischer widerstand fuer eine messonde
US4323875A (en) * 1981-01-21 1982-04-06 Trw, Inc. Method of making temperature sensitive device and device made thereby

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0674157A1 (fr) * 1994-03-24 1995-09-27 Volkswagen Aktiengesellschaft Procédé pour détecter au moins une quantité physique
DE19839631C1 (de) * 1998-08-31 2000-03-30 Siemens Matsushita Components Verfahren zum Herstellen eines Temperatursensors
EP1260804A1 (fr) * 2001-05-22 2002-11-27 Siemens Building Technologies AG Dispositif pour former une moyenne pour la mesure d'une température
EP2065903A1 (fr) * 2007-11-29 2009-06-03 Delphi Technologies, Inc. Méthode de réalisation d'un capteur de suie
US7954230B2 (en) 2007-11-29 2011-06-07 Delphi Technologies, Inc. Method for making soot sensor
WO2009083505A1 (fr) * 2007-12-27 2009-07-09 Robert Bosch Gmbh Procédé pour produire un conducteur électrique par application d'au moins une pâte, en particulier une pâte en couche épaisse
EP2290334A1 (fr) * 2009-09-01 2011-03-02 Siemens Plc Sonde de niveau cryogène
EP2953103A1 (fr) * 2014-06-02 2015-12-09 Siemens Schweiz AG Dispositif d'alarme
WO2018190860A1 (fr) * 2017-04-14 2018-10-18 Hewlett-Packard Development Company, L.P. Dispositifs et procédés de détection de caractéristique de fluide analogique
EP4040126A4 (fr) * 2019-10-01 2023-10-11 Nitto Denko Corporation Film électroconducteur et son procédé de fabrication, film capteur de température et son procédé de fabrication
CN114122540A (zh) * 2021-11-15 2022-03-01 电子科技大学 一种温度检测器及其制备方法、锂电池结构组合

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AU8428991A (en) 1992-03-17

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JP2013211180A (ja) 温度センサ付きフィルムヒータ

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