Fluidic sensor for fluid stream velocity |
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| 申请号 | US3678746D | 申请日 | 1970-06-10 | 公开(公告)号 | US3678746A | 公开(公告)日 | 1972-07-25 |
| 申请人 | SUNDSTRAND DATA CONTROL; | 发明人 | COREY VICTOR B; | ||||
| 摘要 | A method and apparatus for determining the velocity of a fluid flow stream. A fluid jet source is disposed opposite a pair of fluid pressure detectors so that the jet stream equally intersects both detectors when the velocity of the fluid flow stream is zero. Means are provided for relatively laterally displacing the jet with respect to the detectors, and for sensing the pressure difference at the detectors, in order to indicate the velocity of the moving fluid flow stream. | ||||||
| 权利要求 | 1. Apparatus for measuring the velocity of a fluid flow stream in a predetermined direction, comprising: jet means disposed so as to direct a fluid jet stream across said fluid flow stream; detector means disposed opposite said jet means for detecting the jet stream as it passes through said flow stream; means for changing the relative position of said jet means and said detector means so as to cause the jet stream to intersect the detector means even though the flow path of said jet stream be deflected by the flow stream as it passes therethrough; and indicator means responsive to said relative position of said jet means and said detector means for providing an indication of the velocity of the fluid flow stream relative to said apparatus. 2. The measuring apparatus of claim 1 wherein said detector means includes at least two fluid pressure sensitive means disposed in side-by-side relationship opposite said jet means and lying in a plane parallel to the direction of flow of said fluid flow stream. 3. The measuring apparatus of claim 2 wherein said detector means further includes a signal comparison means for comparing the outputs of said pressure sensitive means and producing an error signal in proportion to the difference in pressure between the fluid pressure sensitive means. 4. The measuring apparatus of claim 3 wherein said position changing means is a servo means responsive to said error signal for changing said relative position of said jet means and said detector means until said error signal goes to a null condition. 5. The measuring apparatus of claim 1 wherein said jet means is translatable along an axis parallel with said predetermined direction, said position changing means moving said jet means along said axis until said detector means detects the jet stream in the same manner as when the fluid of said flow stream is stagnant, said indicator means being responsive to the position of said jet means to indicate the velocity of said fluid flow stream. 6. The measuring apparatus of claim 5 wherein said detector means includes a plurality of fluid pressure sensitive means disposed in side-by-side relationship opposite said jet means, differential pressure means coupled to said plurality of pressure sensitive means for generating a differential signal indicating the difference in pressure between said plurality of pressure sensitive means, said indicator means further including means responsive to said differential signal and to the relative position of said jet means for providing an indication of the velocity of said fluid flow stream relative to said apparatus. 7. The measuring apparatus of claim 1 wherein said detector means is translatable along an axis parallel wiTh said predetermined direction, said position changing means moving said detector means along said axis until said detector means detects the jet stream in the same manner as when the fluid of said flow stream is stagnant, said indicator means being responsive to the position of said detector means to indicate the velocity of said fluid flow stream. 8. The measuring apparatus of claim 7 wherein said detector means includes a plurality of fluid pressure sensitive means disposed in side-by-side relationship opposite said jet means, differential pressure means coupled to said plurality of pressure sensitive means for generating a differential signal indicating the difference in pressure between said plurality of pressure sensitive means, said indicator means further including means responsive to said differential signal and to the relative position of said detector means for providing an indication of the velocity of said fluid flow stream relative to said apparatus. 9. The measuring apparatus of claim 1 wherein said jet means includes means for modulating said fluid jet stream, means for generating a signal having a frequency corresponding to the frequency of modulation of said fluid jet stream, and said detector means includes means responsive to said signal for synchronously detecting said jet stream. 10. The measuring apparatus of claim 9 wherein said modulating means includes a device driven at a speed proportional to the frequency of modulation of said fluid jet stream, and said generating means comprises an AC generator driven by said device for producing an AC signal having a frequency corresponding to the frequency of modulation of said fluid jet stream. 11. The measuring apparatus of claim 10 wherein said jet means includes a source of pressurized fluid, nozzle means disposed so as to direct said fluid jet stream across said fluid flow stream to said detector means, first tubing means connecting said pressurized source to said nozzle means, and obstruction means located in the path of said first tubing means and driven by said modulating device to alternately pass and block said pressurized fluid to said nozzle means. 12. The measuring apparatus of claim 11 wherein said obstruction means comprises a member having a plurality of apertures located therein, each aperture being movable by said modulating device into coaxial alignment with said first tubing means to allow the pressurized fluid to pass therethrough. 13. The measuring apparatus of claim 1 for measuring velocity of a fluid flow stream in a first direction when the fluid flow stream has a velocity component along a direction normal to said first direction, wherein said jet means is disposed along said normal direction upstream from said detector means to maintain the impingement of the fluid jet stream upon the detector means. 14. The measuring apparatus of claim 13 wherein said detector means includes a plurality of air pressure sensitive means disposed in side-by-side relationship and lying in a sensitive plane parallel to the direction of airflow along said first direction, and said jet means is disposed so as to direct a fluid jet stream in a plane parallel with said sensitive plane and offset therefrom, said jet means being located upstream from said sensitive plane. 15. A method of determining the flow rate of a moving fluid stream, comprising the steps of: forming a fluid jet stream; directing the jet stream across the path of said moving fluid stream; sensing at spaced locations the pressure of the fluid jet stream after it has passed a given distance through the moving fluid stream; relatively moving the jet stream past the spaced locations until the pressure sensed at the spaced locations is equal; and scaling the relative distance between the jet stream and the spaced locations to provide a measure of the flow rate of the moving fluid stream. 16. The method of claim 15 wherein the step of relatively moving comprises moving the jet streaM relative to the spaced locations. 17. The method of claim 15 wherein the step of relatively moving comprises moving said spaced locations relative to the jet stream. |
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