CA1139961A - Pressure and temperature sensor - Google Patents
Pressure and temperature sensorInfo
- Publication number
- CA1139961A CA1139961A CA000364539A CA364539A CA1139961A CA 1139961 A CA1139961 A CA 1139961A CA 000364539 A CA000364539 A CA 000364539A CA 364539 A CA364539 A CA 364539A CA 1139961 A CA1139961 A CA 1139961A
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- CA
- Canada
- Prior art keywords
- resistance
- resistance member
- substrate
- pressure
- electrode
- Prior art date
- Legal status (The legal status 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 status listed.)
- Expired
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Abstract
ABSTRACT OF THE DISCLOSURE
A hybrid sensor for simultaneously sensing pressure and temperature in non-interacting manner, includes an insulative substrate having a temperature-sensitive printed thick film resistor fabricated thereon. A con-ductive plate is insulatively spaced above the resistor and supported by a pressure-tight insulative barrier. The distributed capacitance between the plate and the resistive pattern is a function of the pressure applied to the exterior face of the plate, while the resistance of the resistive thick film is function of temperature of the surrounding environment.
A hybrid sensor for simultaneously sensing pressure and temperature in non-interacting manner, includes an insulative substrate having a temperature-sensitive printed thick film resistor fabricated thereon. A con-ductive plate is insulatively spaced above the resistor and supported by a pressure-tight insulative barrier. The distributed capacitance between the plate and the resistive pattern is a function of the pressure applied to the exterior face of the plate, while the resistance of the resistive thick film is function of temperature of the surrounding environment.
Description
~3~6~ RD 10635 Background o~ the Invention The present invention relates -to pressure and temperature sensors and, more particularly, to a novel hybrid pressure and temperature sensor for simultaneously sensing pressure and temperature at a single location and in non-interacting manner~
In many forms of apparatus, such as in heat pumps and the like appliances, it is necessary to simultaneously sense pressure and temperature at a parti-cular location. Previously, such parameter sensing hasbeen carried out by the use o~ a pair of sensors at each sensed location. This arrangement is not only relatively costly, but, as the two transducers are not located at exactly the same physical location within the apparatus, also does not provide simultaneous indication of pressure and temperature at exactly the same sensed location. It is desirable to not only sense both pressure and tempera-ture at the same location, in essentially non-interacting manner, but to also sense both parameters with a sinyle sensor having relatively low cost and a minimum parts count.
Brief Summary of the Invention In accordance with the invention, a sensor for simultaneously sensing pressure and temperature at a singl~ location in substantially non-interacting manner, includes an insulative substrate having a patterned thick film resistance element fabricated thereon between first and second terminals, and a conductive plate insulativel~ spaced from the xesistive thick film pattern and connected to a third terminal. A pressure-tight , support of insulative material is fabricated between the periphery of the conductive plate surface closest to the ., ~
, -- 1 --., , ~3~ RD 10635 substrate and the substrate surface, to provide an interior compartment, in which the thick film resistor is enclosed~ at a reference pressure, which may be substantially a vacuum. The sensor is positioned at the location at which pressure and temperature are ta be sensed and pressure thereat exerts a force upon the exterior surface of the conductive plate, varying the spacing between the plate and the resistive thick film to vary the distrihuted capacitance there between as a function of ambient external pressure, substantially independent of ambient temperature. The ambient temperature changes the amount of heat energ~ to vary the resistivity of the thick film resistor with temperature, substantially independent of ambient pressure.
In a preferred embodiment, the substrate is formed of alumina while the printed thick film resistor is formed in a meander or spiral pattern.
Accordingly, it is an object of the present invention to provide a novel sensor for simultaneously sensing pressure and temperature at a single location in substantially non-interacting manner.
This and other objects of the present invention will become apparent upon consideration of the following detailed description, when taken in conjunction with the drawings.
srief Description of the Drawings _ Figure 1 is a prospective view of a first preferred embodiment of the novel pressure and temperature sensor of the present invention;
Figure 2 is a sectional view of the sensor of Figure 1, taken along line 2-2;
Figure 3 is a schematic diagram of equivalent ~ ` RD 10635 circuit of the novel pressurance temperature sensor, and useful in understanding theprinciples of opera-tion thereof;
and Figure 4 is a plan view of another preferred embodiment of the novel pressure and temperature sensor, and of circuitry with which the sensor may be utilized.
Detailed Description of the Invention Referring initially to Figures 1, 2 and 3, in one preferred embodiment of our novel pressure and tempera-ture sensor 10, an insulative substrate 11, of aluminaand the like insulative materials, has a resistance member 12 fabricated upon one surface lla thereof.
Resistor 12 is ad~antageously a pattern of thick-film resistance material placed upon surface lla by printing and the like processes. As best seen in Figure 1 r one presently preferred embodiment of resistance member 12 is a meander-line pattern covering a desired area of length L and width W. The total length and line width, as well as the line thickness, of the resistance film of member 12 is predeterminately selected, along with the resistivity of the resistance material, to provide a desired resistance between the opposed ends 12a and 12b of the resistance element. Ends 12a and 12b are each respectively connected to one of a pair of electrical contacts A and B formed upon substrate surface lla. A
distributed resistance RD is thus formed between contact terminals A and B and the resistance thereof is a function of the temperature at which the resistance material of resistor element 12 i5 maintained; the chan~e o~
resistance, between terminals A and B, with temperature is predeterminately chosen by selection of the resistance material.
~ thin conductive electrode plate 14, which may be of planar configuration, is insulatively supported abo~e subs-trate surface lla to provide a distributed capacitance CD between electrode 14 and resistance element 12 (and each of the contact terminals A and s associated therewith). Electrode 14 is connected by a lead 15 to an associated contact terminal C (also . positioned upon substrate surface lla). Electrode 14 has a length L', greater than the Iength ~ of the ~ 10 resistance pattern, and a width W', greater than the width W of the resistance pattern, to facilitate positioning of a support member 16 between the periphery of the electrode surface 14a, closest to the substrate, and the substrate surface lla. Support 16 is formed of an insulative material and is fabricated in such manner as to form a pressure-tight seal, along line 18, with `. substrate surface lla. The material of support 16 also `~ butts with, and forms a pressure-tight seal over, the . ends 12a and 12b of the resistance member pattern. .-.
After fabrication of supporting rim 16, conductive electrode 14 is positioned upon the rim surface 16a from the substrate and the periphery of electrode surface . .
14b is joined thereto in pressure-tight manner. The volume defined by substrate surface lla, the interior walls of support rim 16 and electrode surface 14a, contains a quality of a dielectric material, which may be vacuum, air and the like dielectri.c materials, introduced during fabrication and serving as the capacitor dielectric.
Electrode 14 acts as a diaphragm deforming responsive to ambient pressure P, at electrode surface 14b, urginy the electrode toward, and away from, resistance member 12 with greater, or lesser, pressure and increasing, ~ RD 10635 or decreasing, the capacitance bet~een terminal C and each of resistance element terminals A and B. The distance D between the interior electrode surface 14a and substrate surface lla is predeterminately established, by selecting the height of rim portion 16, to provide a preselected capacitance value at a reference pressure.
Thus, ambien~ pressure external to the sensor is sensed by variation of distributed capacitance CD, while ~mbient temperature affects the amount of thermal energy received by resistance member 12 within the pressure-tight compart-ment. Deformation of electrode 14, by proper choice of the conductive material and dimensions and shape thereof, is essentially unaffected by the temperature external to sensor 10.
Referring now to Figure 4, another preferred embodiment 10' of our novel pressure and temperature sensor also includes an insulative substrate 11 upon a sur~ace lla of which a resistor member 12' is farbicated.
In this embodiment, resistor member 12' is fabricated as a dual spiral of resistance material with the opposite ends 12a' and 12b' of the resistance element connected to contact terminals A' and B', which may be advantageously positioned adjacent one edge of the substrate. An annular support member 16' is fabricated upon substrate surface lla, with an interior radius R greater than the maximum radius R of the resistant element spiral. Annular support rim 16' is joined to substrate top surface lla to form a pressure tight seal therebetween. A pressure tight seal is also formed where rim 16' passes over end portions of resistance member 12'. A circular conductive electrode member 14' is placed on top of annular support rim 16' and has a maximum radius R", $~
~D 10635 greater than the inner radius R' of support rim lG'. The periphery of the underside of the electrode is sealed to the top of the support rim in pressure-tight manner, whereby a somewhat cylindrical chamber, bounded by substrate surface of electrode 14' closest to the substrate, encloses the spiraled resistance member 12" and a dielectric medium at some reference pressure. Substantially circular electrode 14' is connected to a -third contact terminal Cl by lead 15', which may be fabricated as a conductive film upon the ex-terior surface of support rim 16' and substrate top surface lla.
In operation, a source 30 of D.C. potential of magnitude Vl is coupled in series with a resistor Rt between temperature~sensing terminals A' and B'. The distributed resistance RD, between terminals A' and B', forms a voltage divider with resistance Rt. A voltage Vt appearing between contact terminals A' and B' is a function of the magnitude of D.C. voltage Vl, the resistance of resistor Rt and the temperature-sensitive distributed resistance RD f the sensor. The increase of distributed resistance RD with temperature will cause an increase in the temperature-sensing output voltage Vt.
A source 32 of A.C. voltage of maynitude V2 is connected in series with a fixed resistance Rp between the capacitive electrode contact terminal C' and one of the distributed resistance contact terminals A' and s'. Illustratively~
contact terminal B' acts as the common terminal between the temperature sensing circuitry of source 30 and resis-tance Rt, and the pressure-sensing circuitry of source 32 and resistance R . A voltage V appears betweeen common terminal B' and capacitive electrode contact terminal C' with the same frequency as that of source 32, ~ ~ 3~ RD 10635 and with an amplitude established by the source magnitude V2, the resistance of resistor Rp and the pressure-sensitive magnitude of distributed capacitance CD. An increase in ambient pressure will move eletrode 14' closer to the resistance element, whereby ~he capacitance between terminals C' and B' will increase, thereby decreasing the magnitude of the pressure-sensing voltage Vp.
Advantageously, the potential sources 30 and 32 and the series resistors Rt and Rp are located in a temperature-stable and pressure-stable environment, whereby the changing magnitude of the pressure and temperature, to be simulatan~ously measured at the location of sensor 10', is not present at the location of the sources and series resistors and does not a~fect the magnitudes thereof.
The magnitudes of output voltages Vt and V are then affected only by the respective temperature and pressure to be simultaneously measured. The output voltages Vt and Vp are analog voltages, which may, in manner known to the art, be converted to digital singals, using analog-to-digital converters, voltage-to-frequency converters and the like~ The digital signals may be processed by microcomputers and the like, or the analog signals them-selves may be processed by suitable analog processing circuitry (not shown) for ad~usting the apparatus, in which the pressure and temperature sensor is located, in accordance with the simultaneous pressure and temperature readings achieved by the sensor in substantially non-interacting manner.
While the present invention has been described with respect to several presently preferred embodiments thereof, many modifications and variations will occur to ~D 10635 those skilled in the art. It is our intent, therefore, to be limited only by the scope of the appending claims and no~ by the specific details recited herein.
In many forms of apparatus, such as in heat pumps and the like appliances, it is necessary to simultaneously sense pressure and temperature at a parti-cular location. Previously, such parameter sensing hasbeen carried out by the use o~ a pair of sensors at each sensed location. This arrangement is not only relatively costly, but, as the two transducers are not located at exactly the same physical location within the apparatus, also does not provide simultaneous indication of pressure and temperature at exactly the same sensed location. It is desirable to not only sense both pressure and tempera-ture at the same location, in essentially non-interacting manner, but to also sense both parameters with a sinyle sensor having relatively low cost and a minimum parts count.
Brief Summary of the Invention In accordance with the invention, a sensor for simultaneously sensing pressure and temperature at a singl~ location in substantially non-interacting manner, includes an insulative substrate having a patterned thick film resistance element fabricated thereon between first and second terminals, and a conductive plate insulativel~ spaced from the xesistive thick film pattern and connected to a third terminal. A pressure-tight , support of insulative material is fabricated between the periphery of the conductive plate surface closest to the ., ~
, -- 1 --., , ~3~ RD 10635 substrate and the substrate surface, to provide an interior compartment, in which the thick film resistor is enclosed~ at a reference pressure, which may be substantially a vacuum. The sensor is positioned at the location at which pressure and temperature are ta be sensed and pressure thereat exerts a force upon the exterior surface of the conductive plate, varying the spacing between the plate and the resistive thick film to vary the distrihuted capacitance there between as a function of ambient external pressure, substantially independent of ambient temperature. The ambient temperature changes the amount of heat energ~ to vary the resistivity of the thick film resistor with temperature, substantially independent of ambient pressure.
In a preferred embodiment, the substrate is formed of alumina while the printed thick film resistor is formed in a meander or spiral pattern.
Accordingly, it is an object of the present invention to provide a novel sensor for simultaneously sensing pressure and temperature at a single location in substantially non-interacting manner.
This and other objects of the present invention will become apparent upon consideration of the following detailed description, when taken in conjunction with the drawings.
srief Description of the Drawings _ Figure 1 is a prospective view of a first preferred embodiment of the novel pressure and temperature sensor of the present invention;
Figure 2 is a sectional view of the sensor of Figure 1, taken along line 2-2;
Figure 3 is a schematic diagram of equivalent ~ ` RD 10635 circuit of the novel pressurance temperature sensor, and useful in understanding theprinciples of opera-tion thereof;
and Figure 4 is a plan view of another preferred embodiment of the novel pressure and temperature sensor, and of circuitry with which the sensor may be utilized.
Detailed Description of the Invention Referring initially to Figures 1, 2 and 3, in one preferred embodiment of our novel pressure and tempera-ture sensor 10, an insulative substrate 11, of aluminaand the like insulative materials, has a resistance member 12 fabricated upon one surface lla thereof.
Resistor 12 is ad~antageously a pattern of thick-film resistance material placed upon surface lla by printing and the like processes. As best seen in Figure 1 r one presently preferred embodiment of resistance member 12 is a meander-line pattern covering a desired area of length L and width W. The total length and line width, as well as the line thickness, of the resistance film of member 12 is predeterminately selected, along with the resistivity of the resistance material, to provide a desired resistance between the opposed ends 12a and 12b of the resistance element. Ends 12a and 12b are each respectively connected to one of a pair of electrical contacts A and B formed upon substrate surface lla. A
distributed resistance RD is thus formed between contact terminals A and B and the resistance thereof is a function of the temperature at which the resistance material of resistor element 12 i5 maintained; the chan~e o~
resistance, between terminals A and B, with temperature is predeterminately chosen by selection of the resistance material.
~ thin conductive electrode plate 14, which may be of planar configuration, is insulatively supported abo~e subs-trate surface lla to provide a distributed capacitance CD between electrode 14 and resistance element 12 (and each of the contact terminals A and s associated therewith). Electrode 14 is connected by a lead 15 to an associated contact terminal C (also . positioned upon substrate surface lla). Electrode 14 has a length L', greater than the Iength ~ of the ~ 10 resistance pattern, and a width W', greater than the width W of the resistance pattern, to facilitate positioning of a support member 16 between the periphery of the electrode surface 14a, closest to the substrate, and the substrate surface lla. Support 16 is formed of an insulative material and is fabricated in such manner as to form a pressure-tight seal, along line 18, with `. substrate surface lla. The material of support 16 also `~ butts with, and forms a pressure-tight seal over, the . ends 12a and 12b of the resistance member pattern. .-.
After fabrication of supporting rim 16, conductive electrode 14 is positioned upon the rim surface 16a from the substrate and the periphery of electrode surface . .
14b is joined thereto in pressure-tight manner. The volume defined by substrate surface lla, the interior walls of support rim 16 and electrode surface 14a, contains a quality of a dielectric material, which may be vacuum, air and the like dielectri.c materials, introduced during fabrication and serving as the capacitor dielectric.
Electrode 14 acts as a diaphragm deforming responsive to ambient pressure P, at electrode surface 14b, urginy the electrode toward, and away from, resistance member 12 with greater, or lesser, pressure and increasing, ~ RD 10635 or decreasing, the capacitance bet~een terminal C and each of resistance element terminals A and B. The distance D between the interior electrode surface 14a and substrate surface lla is predeterminately established, by selecting the height of rim portion 16, to provide a preselected capacitance value at a reference pressure.
Thus, ambien~ pressure external to the sensor is sensed by variation of distributed capacitance CD, while ~mbient temperature affects the amount of thermal energy received by resistance member 12 within the pressure-tight compart-ment. Deformation of electrode 14, by proper choice of the conductive material and dimensions and shape thereof, is essentially unaffected by the temperature external to sensor 10.
Referring now to Figure 4, another preferred embodiment 10' of our novel pressure and temperature sensor also includes an insulative substrate 11 upon a sur~ace lla of which a resistor member 12' is farbicated.
In this embodiment, resistor member 12' is fabricated as a dual spiral of resistance material with the opposite ends 12a' and 12b' of the resistance element connected to contact terminals A' and B', which may be advantageously positioned adjacent one edge of the substrate. An annular support member 16' is fabricated upon substrate surface lla, with an interior radius R greater than the maximum radius R of the resistant element spiral. Annular support rim 16' is joined to substrate top surface lla to form a pressure tight seal therebetween. A pressure tight seal is also formed where rim 16' passes over end portions of resistance member 12'. A circular conductive electrode member 14' is placed on top of annular support rim 16' and has a maximum radius R", $~
~D 10635 greater than the inner radius R' of support rim lG'. The periphery of the underside of the electrode is sealed to the top of the support rim in pressure-tight manner, whereby a somewhat cylindrical chamber, bounded by substrate surface of electrode 14' closest to the substrate, encloses the spiraled resistance member 12" and a dielectric medium at some reference pressure. Substantially circular electrode 14' is connected to a -third contact terminal Cl by lead 15', which may be fabricated as a conductive film upon the ex-terior surface of support rim 16' and substrate top surface lla.
In operation, a source 30 of D.C. potential of magnitude Vl is coupled in series with a resistor Rt between temperature~sensing terminals A' and B'. The distributed resistance RD, between terminals A' and B', forms a voltage divider with resistance Rt. A voltage Vt appearing between contact terminals A' and B' is a function of the magnitude of D.C. voltage Vl, the resistance of resistor Rt and the temperature-sensitive distributed resistance RD f the sensor. The increase of distributed resistance RD with temperature will cause an increase in the temperature-sensing output voltage Vt.
A source 32 of A.C. voltage of maynitude V2 is connected in series with a fixed resistance Rp between the capacitive electrode contact terminal C' and one of the distributed resistance contact terminals A' and s'. Illustratively~
contact terminal B' acts as the common terminal between the temperature sensing circuitry of source 30 and resis-tance Rt, and the pressure-sensing circuitry of source 32 and resistance R . A voltage V appears betweeen common terminal B' and capacitive electrode contact terminal C' with the same frequency as that of source 32, ~ ~ 3~ RD 10635 and with an amplitude established by the source magnitude V2, the resistance of resistor Rp and the pressure-sensitive magnitude of distributed capacitance CD. An increase in ambient pressure will move eletrode 14' closer to the resistance element, whereby ~he capacitance between terminals C' and B' will increase, thereby decreasing the magnitude of the pressure-sensing voltage Vp.
Advantageously, the potential sources 30 and 32 and the series resistors Rt and Rp are located in a temperature-stable and pressure-stable environment, whereby the changing magnitude of the pressure and temperature, to be simulatan~ously measured at the location of sensor 10', is not present at the location of the sources and series resistors and does not a~fect the magnitudes thereof.
The magnitudes of output voltages Vt and V are then affected only by the respective temperature and pressure to be simultaneously measured. The output voltages Vt and Vp are analog voltages, which may, in manner known to the art, be converted to digital singals, using analog-to-digital converters, voltage-to-frequency converters and the like~ The digital signals may be processed by microcomputers and the like, or the analog signals them-selves may be processed by suitable analog processing circuitry (not shown) for ad~usting the apparatus, in which the pressure and temperature sensor is located, in accordance with the simultaneous pressure and temperature readings achieved by the sensor in substantially non-interacting manner.
While the present invention has been described with respect to several presently preferred embodiments thereof, many modifications and variations will occur to ~D 10635 those skilled in the art. It is our intent, therefore, to be limited only by the scope of the appending claims and no~ by the specific details recited herein.
Claims (9)
1. A sensor for simultaneously sensing temperature and pressure at a single location and in substantially non-interacting manner, comprising:
a substrate of an insulative material, said substrate having a surface;
a resistance member fabricated upon said substrate surface, said resistance member having first and second ends between which an electrical resistance is measurable;
a single flexible conductive electrode spaced from said resistance member and said substrate surface;
an insulative support rim extending from said substrate surface to the periphery of a surface of said conductive electrode nearest to said substrate, said substrate rim joined to said substrate surface and to only the periphery of said electrode to form a pressure-tight cavity enclosing said resistance member;
and a dielectric material enclosed within said cavity and at a reference pressure;
said resistance member being formed of a resistance material responsive to changes in external temperature for continuously varying the electrical resistance between said resistance member ends; said conductive electrode responsive to changes in external pressure for continuously varying the distributed electrical capacitance between said electrode and said resistance member.
a substrate of an insulative material, said substrate having a surface;
a resistance member fabricated upon said substrate surface, said resistance member having first and second ends between which an electrical resistance is measurable;
a single flexible conductive electrode spaced from said resistance member and said substrate surface;
an insulative support rim extending from said substrate surface to the periphery of a surface of said conductive electrode nearest to said substrate, said substrate rim joined to said substrate surface and to only the periphery of said electrode to form a pressure-tight cavity enclosing said resistance member;
and a dielectric material enclosed within said cavity and at a reference pressure;
said resistance member being formed of a resistance material responsive to changes in external temperature for continuously varying the electrical resistance between said resistance member ends; said conductive electrode responsive to changes in external pressure for continuously varying the distributed electrical capacitance between said electrode and said resistance member.
2. The sensor of claim 1, wherein the substrate is formed of alumina.
3. The sensor of claim 1, wherein the resistance member is fabricated of a thick-film resistance material.
4. The sensor of claim 3, wherein said resistance member is formed in a meander-line configuration.
5. The sensor of claim 3, wherein the resistance member is formed as a dual-spiral pattern.
6. The sensor of claim 5, wherein the dual-spiral resistance member has a maximum radius R; said electrode is substantially circular and of radius R" greater than R; and said support rim is of annular shape with an inner radius R
greater than R and less than R".
greater than R and less than R".
7. A sensor for simultaneously sensing temperature and pressure at a single location and in substantially non-interacting manner, comprising:
a substrate of an insulating material, said substrate having a surface;
a resistance member fabricated of a thick-film resistance material upon said substrate surface, said resistance member having a meander-line configuration with first and second ends between which an electrical. resistance is measurable;
the meander-line resistance member covering an area of length L and width W;
a flexible conductive electrode spaced from said resistance member and said substrate surface; said electrode being of substantially rectangular shape and having a length L' greater than length L and a width W' greater than width W;
an insulated support rim extending from said substrate surface to the periphery of a surface of said conducting electrode nearest to said substrate, said support rim having length and width inner dimensions respectively greater than L and W and less than L' and W' and joined to said substrate surface and said electrode to form a pressure-tight cavity enclosing said resistance member; and a dielectric material enclosed within said cavity and at a reference pressure;
said resistance member being formed of a resistance material responsive to changes in external temperature for varying the electrical resistance between said resistance member ends; said conductive electrode responsive to changes in external pressure for varying the distributed electrical capacitance between said electrode and said resistance member.
a substrate of an insulating material, said substrate having a surface;
a resistance member fabricated of a thick-film resistance material upon said substrate surface, said resistance member having a meander-line configuration with first and second ends between which an electrical. resistance is measurable;
the meander-line resistance member covering an area of length L and width W;
a flexible conductive electrode spaced from said resistance member and said substrate surface; said electrode being of substantially rectangular shape and having a length L' greater than length L and a width W' greater than width W;
an insulated support rim extending from said substrate surface to the periphery of a surface of said conducting electrode nearest to said substrate, said support rim having length and width inner dimensions respectively greater than L and W and less than L' and W' and joined to said substrate surface and said electrode to form a pressure-tight cavity enclosing said resistance member; and a dielectric material enclosed within said cavity and at a reference pressure;
said resistance member being formed of a resistance material responsive to changes in external temperature for varying the electrical resistance between said resistance member ends; said conductive electrode responsive to changes in external pressure for varying the distributed electrical capacitance between said electrode and said resistance member.
8. In combination, a sensor for simultaneously sensing temperature and pressure at a single location and in substantially non-interacting manner, comprising:
a substrate of an insulative material, said substrate having a surface;
a resistance member fabricated upon said substrate surface, said resistance member having first and second ends between which an electrical resistance is measurable;
a flexible conductive electrode spaced from said resistance member and said substrate surface;
an insulative support rim extending from said substrate surface to the periphery of a surface of said conductive electrode nearest to said substrate, said substrate rim joined to said substrate surface and to said electrode periphery to form a pressure-tight cavity enclosing said resistance member; and a dielectric material enclosed within said cavity and at a reference pressure;
said resistance member being formed of a resistance material responsive to changes in external temperature for varying the electrical resistance between said resistance member ends; said conductive electrode responsive to changes in external pressure for varying the distributed electrical capacitance between said electrode and said resistance member;
a source of a D.C. potential, said source having a first terminal connected to one of the resistance member ends and a second terminal;
a first fixed resistance connected between said D.C.
source second terminal and the remaining one of said resistance member ends;
a source of an A.C. potential, said source having a first terminal connected to said one of the resistance member ends and a second terminal; and a second fixed resistance connected between said A.C. source second terminal and said electrode.
a substrate of an insulative material, said substrate having a surface;
a resistance member fabricated upon said substrate surface, said resistance member having first and second ends between which an electrical resistance is measurable;
a flexible conductive electrode spaced from said resistance member and said substrate surface;
an insulative support rim extending from said substrate surface to the periphery of a surface of said conductive electrode nearest to said substrate, said substrate rim joined to said substrate surface and to said electrode periphery to form a pressure-tight cavity enclosing said resistance member; and a dielectric material enclosed within said cavity and at a reference pressure;
said resistance member being formed of a resistance material responsive to changes in external temperature for varying the electrical resistance between said resistance member ends; said conductive electrode responsive to changes in external pressure for varying the distributed electrical capacitance between said electrode and said resistance member;
a source of a D.C. potential, said source having a first terminal connected to one of the resistance member ends and a second terminal;
a first fixed resistance connected between said D.C.
source second terminal and the remaining one of said resistance member ends;
a source of an A.C. potential, said source having a first terminal connected to said one of the resistance member ends and a second terminal; and a second fixed resistance connected between said A.C. source second terminal and said electrode.
9. The sensor combination of claim 8, wherein said D.C. and A.C. sources and said first and second fixed resistances are at a location removed from the location of said sensor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000364539A CA1139961A (en) | 1980-11-13 | 1980-11-13 | Pressure and temperature sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000364539A CA1139961A (en) | 1980-11-13 | 1980-11-13 | Pressure and temperature sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1139961A true CA1139961A (en) | 1983-01-25 |
Family
ID=4118427
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000364539A Expired CA1139961A (en) | 1980-11-13 | 1980-11-13 | Pressure and temperature sensor |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1139961A (en) |
-
1980
- 1980-11-13 CA CA000364539A patent/CA1139961A/en not_active Expired
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |