초록 ▼

A rugged microsensor assembly is disclosed that measures both the velocity and angular direction of an incoming air stream. The microsensor assembly includes at least two flow sensors, each orientated to measure a different velocity component of the incoming air stream. The velocity components are r

A rugged microsensor assembly is disclosed that measures both the velocity and angular direction of an incoming air stream. The microsensor assembly includes at least two flow sensors, each orientated to measure a different velocity component of the incoming air stream. The velocity components are related by the geometry between the sensors, and the angular direction and velocity of the incoming air stream are determined by examining the measured velocity components. The preferred sensor is a fully passivated thermal differential microanemometer with back contacts, designed to operate in harsh environments.

대표청구항 ▼

A rugged microsensor assembly is disclosed that measures both the velocity and angular direction of an incoming air stream. The microsensor assembly includes at least two flow sensors, each orientated to measure a different velocity component of the incoming air stream. The velocity components are r

A rugged microsensor assembly is disclosed that measures both the velocity and angular direction of an incoming air stream. The microsensor assembly includes at least two flow sensors, each orientated to measure a different velocity component of the incoming air stream. The velocity components are related by the geometry between the sensors, and the angular direction and velocity of the incoming air stream are determined by examining the measured velocity components. The preferred sensor is a fully passivated thermal differential microanemometer with back contacts, designed to operate in harsh environments. ected with threads, and said retriever head is mounted onto the front shell. 9. The apparatus of claim 4, wherein said means for heat insulation comprises: a thermal insulation flask comprising two concentric cylinders which are made of two polished smooth metal sheets and a sandwich layer between said two metal cylinders that is evacuated and sealed and a thermal flask stopper comprising an evenly distributed thermal tube inserted into said thermal insulation flask. 10. The apparatus of claim 4, wherein said means for sensing total pressure P1 and aridity ρ comprises: a first light source for generating light; a first sensing element for sensing total pressure and aridity, having a truncated cone shape with the larger end exposed to the variable condition to be sensed and the smaller end of said first sensing element oriented toward the inside of the apparatus and wherein said larger end of the first sensing element is polished into an ellipsoidal shape; the first sensing element is interference fit to a first base, and said first base is mounted on said front shell with threads; a first optical fiber for transmitting said first light from said first light source to said first sensing element through a polarizer; a second optical fiber for receiving first light from said first sensing element and a second polarizer, and terminating in photoelectric converter, thus providing values for the total pressure of steam due to the photoelastic effect on the specially shaped and dimensioned sensing element; a third optical fiber for transmitting a first light from the same first light source to the smaller end of the same sensing element; and a fourth optical fiber for transmitting said first light from the first sensing element to a photoelectric converter for providing values of the aridity of steam. 11. The apparatus of claim 6, wherein said first sensing element is a sapphire crystal. 12. The apparatus of claim 6, wherein said first sensing element is a ruby crystal. 13. The apparatus of claim 6, wherein said first sensing element further comprises at least one additional layer adhered to the larger end ellipsoid surface of the truncated cone shaped crystal to improve the sensing and anti-corrosion performance. 14. The apparatus of claim 4, wherein said means for sensing still pressure P2 and temperature T comprises: a second light source for generating a second light; a buffer grid comprising several rows of mismatched small tubes fabricated on the wall of the front shell and a blind hole behind said buffer grid for the purpose of having the steam inside said blind hole motionless; a second sensing element for sensing still pressure and temperature having a truncated cone shape with the larger end exposed to the blind hole, i.e., to the variable condition to be sensed, and the smaller end of said second sensing element toward the inner part of the apparatus said larger end of the second sensing element is polished into a sphere or curved shape; the second sensing element is interference fit to a second base, and said second base is mounted on said front shell with threads; a fifth optical fiber for transmitting said second light from said second light source to said second sensing element through a third polarizer; a sixth optical fiber for receiving light from said second sensing element and a fourth polarizer, and terminating in an photoelectric converter, thus providing values for the still pressure of steam due to the photoelastic effect on the second specially shaped and dimensional sensing element; a hollow optical fiber coated with a metal connected to the small end surface of the second sensing element and terminating in a thermopile detector, providing a means for the measurement of the temperature of steam; and a temperature compensation element connected to a second hollow optical fiber, and placed inside said evenly distributed tube. 15. The apparatus of claim 13, wherein said second sens ing element is a sapphire crystal. 16. The apparatus of claim 13, wherein said second sensing element is a ruby crystal. 17. The apparatus of claim 13, wherein said second sensing element further comprises at least one additional layer adhered to the larger end curved surface of the crystal to improve the sensing and anti-corrosion performance. 18. The apparatus of claim 4, wherein said means for sensing steam flow rate of the steam can thus be determined by v2=2(P1-P2)/ρ, where v is the steam flow rate, P1 is the total pressure of steam, P2 is the still pressure of steam, and ρ is the aridity of steam. 19. The apparatus of claim 4, wherein said means for sensing kinetic pressure P can thus be determined by P=P1-P2, where P1 is the total pressure of steam, and P2 is the still pressure of steam. 20. The apparatus of claim 4, wherein said means for electronic communication and processing comprises means for obtaining, processing and saving the data obtained from all the six sensors and temperature compensation element, said means for electronic communication and processing is placed inside the evenly distributed thermal tube. 21. The apparatus of claim 4 wherein said retriever socket is used to connect with a computer for the further data processing, display, printing and storage, the retriever socket is mounted with the front shell and can be separated with the back shell part. 22. The apparatus of claim 6, wherein the hollow cylinder is composed of stainless steel. 23. The apparatus of claim 14, wherein said temperature compensation element comprises a thermopile detector. d the second sensor axis intersect at an angle of less than 90 degrees. 10. A sensor assembly according to claim 9, wherein the first sensor axis and the second sensor axis intersect at an angle of 90-X degrees, where X is greater than zero. 11. A sensor assembly according to claim 9, where the determining means determines the velocity of the incoming fluid stream from the output signal of the first sensor and the output signal of the second sensor using the relation: v={ΔGA2+ΔGB2-1.5ΔGAΔGBcos(90 +X)}n/2. 12. A sensor assembly for detecting the angular direction of an incoming fluid stream having a velocity, the sensor comprising: a first microbridge flow sensor having at least one elongated heater strip and at least one elongated sensor strip both in thermal communication with the incoming fluid stream, the at least one elongated sensor strip laterally spaced from the at least one elongated heater strip, both the at least one elongated heater strip and the at least one elongated sensor strip extending at least substantially perpendicular to a first sensor axis, the first microbridge flow sensor providing an output signal that is related to the component of the velocity of the incoming fluid stream that extends along the first sensor axis; a second microbridge flow sensor having at least one elongated heater strip and at least one elongated sensor strip both in thermal communication with the incoming fluid stream, the at least one elongated sensor strip laterally spaced from the at least one elongated heater strip, both the at least one elongated heater strip and the at least one elongated sensor strip extending at least substantially perpendicular to a second sensor axis, the second microbridge flow sensor providing an output signal that is related to the component of the velocity of the incoming fluid stream that extends along the second sensor axis; the first microbridge flow sensor and the second microbridge flow sensor positioned such that the first sensor axis intersects the second sensor axis at a point; and determining means for determining the angular direction of the incoming fluid stream from the output signal of the first microbridge flow sensor and the output signal of the second microbridge flow sensor. 13. A sensor assembly according to claim 12, wherein the determining means further determines the velocity of the incoming fluid stream from the output signal of the first microbridge flow sensor and the output signal of the second microbridge flow sensor. 14. A sensor assembly according to claim 13, wherein the first sensor axis and the second sensor axis intersect at an angle of about 90 degrees. 15. A sensor assembly according to claim 14, wherein the determining means determines the velocity of the incoming fluid stream from the output signal of the first microbridge flow sensor and the output signal of the second microbridge flow sensor using the relation: where, ΔGA=the first microbridge flow sensor output signal; ΔGB=the second microbridge flow sensor output signal; and n=scaling factor. 16. A sensor assembly according to claim 15, where n=2. 17. A sensor assembly according to claim 16, wherein the determining means determines the angular direction of the incoming fluid stream from the output signal of the first microbridge flow sensor and the output signal of the second microbridge flow sensor using the relation: where, B=90-A. 18. A sensor assembly according to claim 13, wherein the first sensor axis and the second sensor axis intersect at an angle of less than 90 degrees. 19. A sensor assembly according to claim 18, wherein the first sensor axis and the second sensor axis intersect at an angle of 90-X degrees, where X is greater than zero. 20. A sensor assembly according to claim 19, where the determining means determines the velocity of the incoming fluid stream from the output si