초록 ▼

A fluid measurement gauge is principally used to measure the fluid level in large underground storage tanks, such as for storing gasoline at service stations. A housing is positioned vertically in the fluid and includes a leadscrew which is driven by a stepper motor. A nut is mounted for longitudina

A fluid measurement gauge is principally used to measure the fluid level in large underground storage tanks, such as for storing gasoline at service stations. A housing is positioned vertically in the fluid and includes a leadscrew which is driven by a stepper motor. A nut is mounted for longitudinal movement along the leadscrew. A float encircles the housing and includes a magnet at the surface of the fluid level. A magnetic sensor, such as a Hall-effect switch, is mounted on the nut and driven in selected steps downward to encounter the magnet mounted in the float. A reference position is marked at the top of the housing and the fluid level is measured downward from the reference position by detecting the magnet by operation of the magnetic sensor. An additional float can be provided to detect the interface between two fluids such as gasoline and water. The second float is further provided with a magnet to be detected by the magnetic sensor. In addition, temperature sensors, such as thermistors, can be mounted near the housing to measure the temperature of the fluid for compensation to standard conditions. An electronic circuit board can be included within the fluid measurement gauge to provide an integral unit for making periodic, unattended fluid measurements.

대표청구항 ▼

1. A fluid measurement gauge, comprising: a housing for extending into a fluid, a leadscrew within said housing, means for rotationally driving said leadscrew, means threadably engaged to said leadscrew for longitudinally traversing along said leadscrew in response to rotation of said leadscre

1. A fluid measurement gauge, comprising: a housing for extending into a fluid, a leadscrew within said housing, means for rotationally driving said leadscrew, means threadably engaged to said leadscrew for longitudinally traversing along said leadscrew in response to rotation of said leadscrew, a float positioned exterior to said housing for floating at the surface of said fluid, a magnet mounted to said float, and a magnetic sensor mounted to said means engaged to said leadscrew for producing a detection signal when said sensor is in the vicinity of said magnet for detecting the level of said fluid. 2. A fluid measurement gauge as recited in claim 1 wherein said housing comprises a fluid-tight, elongate cylinder vertically extending into said fluid. 3. A fluid measurement gauge as recited in claim 1 wherein said leadscrew is mounted coaxially within said housing to extend substantially the length of said housing. 4. A fluid measurement gauge as recited in claim 1 wherein said means engaged to said leadscrew is a nut threaded on said leadscrew. 5. A fluid measurement gauge as recited in claim 1 wherein said means for rotationally driving said leadscrew is a stepper motor. 6. A fluid measurement gauge as recited in claim 1 wherein said float comprises a ring which encircles said housing. 7. A fluid measurement gauge as recited in claim 1 wherein said magnetic sensor comprises a Hall-effect device for detecting the proximity of said magnet. 8. A fluid measurement gauge as recited in claim 1, including: a second float positioned exterior to said housing and below said first float, said second float for floating at the interface of two fluids, and a second magnet mounted on said second float. 9. A fluid measurement gauge as recited in claim 1 including at least one guide rod within said housing, said guide rod parallel to said leadscrew and positioned to prevent rotation of said means engaged to said leadscrew relative to said housing. 10. A fluid measurement gauge as recited in claim 1 including an electronic module for controlling said means for rotationally driving said leadscrew and for receiving said detection signal produced by said magnetic sensor. 11. A fluid measurement gauge as recited in claim 1 including at least one guide rod within, but electrically insulated from said housing, for preventing rotation of said means engaged to said leadscrew and for transmitting said detection signal through said guide rod. 12. A fluid measurement gauge as recited in claim 11 including brushes mounted on said means engaged to said leadscrew and touching said guide rod for providing an electrical path from said magnetic sensor to said guide rod. 13. A fluid measurement gauge as recited in claim 1 including top and bottom plates for closing said housing. 14. A fluid measurement gauge as recited in claim 1 including at least one guide rod mounted exterior to said housing for positioning said float relative to said housing. 15. A fluid measurement gauge as recited in claim 1 including a temperature sensor mounted to said housing on the exterior thereof for measuring the temperature of said fluid. 16. A fluid measurement gauge as recited in claim 15 including means for detecting when said means engaged to said leadscrew is at a predetermined reference position. 17. A fluid measurement gauge as recited in claim 16 wherein said means for detecting comprises an optical sensor which generates a reference position signal when said means engaged to said leadscrew reaches said predetermined reference position. 18. A fluid measurement gauge, comprising: an elongate cylindrical housing for extending vertically into a body of fluid, a leadscrew extending coaxially within said housing, a motor connected to rotationally drive said leadscrew, a nut threadedly engaged to said leadscrew for longitudinally traversing said leadscrew when said leadscrew is rotated relative to said nut, a float encircling said housing and floating at the surface of said fluid, a magnet mounted to said float, a magnetic sensor mounted on said nut for generating a detection signal when said magnet is in the vicinity of said sensor for detecting the level of said fluid, and means for electrically communicating said detection signal from said magnetic sensor to outside said housing. 19. A fluid measurement gauge as recited in claim 18 wherein said motor is an electrical stepper motor. 20. A fluid measurement gauge as recited in claim 18 wherein said magnetic sensor is a Hall-effect device for detecting the proximity of said magnet. 21. A fluid measurement gauge as recited in claim 18 wherein said means for electrically communicating comprises first and second guide rods mounted inside said housing parallel to said leadscrew and positioned to prevent rotation of said nut relative to said guide rods, at least one of said guide rods electrically insulated from said housing. 22. A fluid measurement gauge as recited in claim 21 including brushes mounted on said nut and touching said guide rods for providing electrical communication between said magnetic sensor and said guide rods. 23. A fluid measurement gauge as recited in claim 18, including: a second float encircling said housing and positioned below said first float, and a second magnet mounted on said second float. 24. A fluid measurement gauge as recited in claim 18 including top and bottom plates for closing said housing. 25. A fluid measurement gauge as recited in claim 18 including a guide rod exterior to said housing for positioning said float relative to said housing. 26. A fluid measurement gauge as recited in claim 18 including a temperature sensor mounted to said housing on the exterior thereof for measuring the temperature of said fluid. 27. A fluid measurement gauge as recited in claim 18 including means for detecting when said nut is at a predetermined reference position. 28. A fluid measurement gauge as recited in claim 27 wherein said means for detecting comprises an optical sensor which generates a reference position signal when said nut reaches said predetermined reference position. 29. A fluid measurement gauge, comprising: an elongate, fluid-tight cylindrical housing for extending vertically into a body of fluid, a leadscrew mounted coaxially within said housing and supported by upper and lower bearings, a stepper motor connected to rotationally drive said leadscrew, a nut threadedly engaged to said leadscrew for longitudinally traversing said leadscrew when said leadscrew is rotated relative to said nut, first and second guide rods within said housing parallel to said leadscrew and positioned to prevent rotation of said nut, at least one of said guide rods electrically insulated from said housing, said guide rods serving as electrical conduction paths, a float encircling said housing and floating at the surface of said fluid, a magnet mounted to said float, a Hall-effect magnetic sensor mounted on said nut for generating a detection signal when said magnet is in the vicinity of said sensor for detecting the level of said fluid, brushes connected to said magnetic sensor and touching said guide rods for transmitting said detection signal from said sensor to said guide rods, and an optical sensor for generating a reference position signal when said magnetic sensor reaches a predetermined reference position wherein said fluid level is measured as the distance from said reference position to a position of said magnetic sensor where said detection signal is generated.