Flow meter device
A device having a first flow meter ( 2 ) and a second flow meter ( 3 ). The first and the second flow meters work according to a Coriolis principle. The first flow meter includes a first measuring tube ( 7 ). The second flow meter includes a second measuring tube ( 10 ). The first flow meter and the second flow meter are disposed in a common housing ( 4,5,6 ). The first flow meter and the second flow meters have different eigenfrequencies because of a first vibration-influencing device ( 18 ) attached to the first flow meter and a second vibration-influencing device ( 19 ) attached to the second flow meter.
1. A device comprising:
a first flow meter, working according to Coriolis principle, said first flow meter including a first measuring tube;
a second flow meter, working according to Coriolis principle, said second flow meter including a second measuring tube;
said first flow meter and said second flow meter being disposed in a common housing and
said first flow meter and said second flow meter having different eigenfrequencies because of a first vibration-influencing device attached to the first flow meter and a second vibration-influencing device attached to the second flow meter.
2. The device of claim 1 , wherein the first vibration-influencing device is located at a relative position different from a relative position of the second vibration-influencing device.
3. The device of claim 2 wherein at least one of the first and the second vibration-influencing devices is configured as a passive device.
4. The device of claim 2 wherein the first and the second flow meters have similar structures except for the first and the second vibration-influencing devices.
5. The device of claim 2 wherein the first and the second measuring tube each has at least two loops, the two loops in the first measuring tube being interconnected by at least a first coupling element that forms the first vibration-influencing device, the two loops in the second measuring tube being interconnected by at least a second coupling element that forms the second vibration-influencing device.
6. The device of claim 5 , wherein a third and a fourth coupling elements are provided for the first and the second measuring tubes, respectively.
7. The device of claim 6 , wherein the coupling elements on each measuring tube are arranged equidistantly from the ends of the respective measuring tube.
8. The device of claim 5 , wherein the coupling elements are plates and the corresponding measuring tubes are aligned perpendicularly to the plate.
9. The device of claim 8 , wherein the plates are fixed relative to a first chassis corresponding to the first flow meter and a second chassis corresponding to the second flow meter, wherein the plates corresponding to the first flow meter are fixed at a first locating position on the first chassis and the plates corresponding to the second flow meter are fixed at a second locating position on the second chassis.
10. The device of claim 9 , wherein the first and the second locating positions are defined by structures on the first and the second chassis, respectively.
11. The device of claim 10 , wherein the plates are configured to be inserted into the corresponding structures.
12. The device of claim 10 , wherein the first and the second locating positions are defined by at least three projecting parts each located in the first and the second chassis, said projecting parts protruding toward the first and the second measuring tubes respectively.
13. The device of claim 9 , wherein the first and the second locating positions are spaced apart from each other by a distance on the order of one centimeter.
14. The device of claim 5 , wherein a respective strain gauge is disposed on each of the first and the second coupling elements.
15. The device of claim 1 , wherein the first flow meter has a first electronic control unit and the second flow meter has a second electronic control unit, wherein the first and the second electronic control units monitor each other.