MEASURING DEVICE WITH A FLOWMETER AND METHOD FOR OPERATING A MEASURING DEVICE

Abstract

A measuring device has a flowmeter, an inlet tube and an outlet tube. The flowmeter has a measuring tube that is connected to the inlet tube and to the outlet tube. To provide a measuring device that allows for measurements using a flowmeter, in particular of the liquid components of medium in the measuring tube, independent of whether the medium is made to flow or is stagnant, wherein the measuring tube is completely filled at least with the liquid components of the medium when the medium is stagnant the inlet tube, the measuring tube and the outlet tube form a siphon, wherein the siphon is designed and aligned in respect to the vector of the gravitational field of the earth so that, when a medium initially flows through the siphon and then the flowing of the medium stops, the measuring tube is completely filled with the stagnant medium.

Claims

1. A measuring device, comprising: a flowmeter having a measuring tube, an inlet tube and an outlet tube, wherein the measuring tube is connected to the inlet tube and to the outlet tube, wherein the inlet tube, the measuring tube and the outlet tube form a siphon, wherein the siphon is aligned in respect to a vector of the gravitational field of the earth so that, when a medium initially flows through the siphon and then flowing of the medium stops, the measuring tube is completely filled with a stagnant medium.

2. The measuring device according to claim 1, wherein the flowmeter is a nuclear magnetic flowmeter.

3. The measuring device according to claim 1, wherein the measuring tube is straight and has a measuring tube longitudinal axis that is aligned perpendicular to the vector of the gravitational field of the earth.

4. The measuring device according to any claim 1, wherein the inlet tube and the outlet tube each have a first tube segment with a first tube segment longitudinal axis, a second tube segment with a second tube segment longitudinal axis and a third tube segment, wherein the first tube segment is connected to the measuring tube, wherein the first tube segment and the second tube segment are connected to one another by the third tube segment, and wherein the first tube segment longitudinal axis and the second tube segment longitudinal axis are spaced by a tube segment distance and are parallel to one another.

5. The measuring device according to claim 4, wherein the tube segment distance is adapted to cause the measuring tube to be completely filled with the stagnant medium when a flow of medium through the inlet tube, the measuring tube and the outlet tube at an assumed maximum flow velocity stops.

6. The measuring device according to claim 1, wherein the inlet tube and the outlet tube each have a first tube segment, a second tube segment and a third tube segment, wherein the first tube segment is connected to the measuring tube, the first tube segment and the second tube segment are connected to one another by the third tube segment, a projection of a first tube inner cross section surface of the first tube segment on a projection plane and a projection of a second tube inner cross section surface of the second tube segment on the projection plane do not intersect in the projection plane.

7. The measuring device according to claim 1, wherein a valve is arranged in each of the inlet tube and the outlet tube to control the flow of a medium through the measuring tube.

8. The measuring device according to claim 7, wherein the inlet tube and the outlet tube each have a first tube segment with a first tube segment longitudinal axis, a second tube segment with a second tube segment longitudinal axis and a third tube segment, wherein the first tube segment is connected to the measuring tube, wherein the first tube segment and the second tube segment are connected to one another by the third tube segment, wherein the first tube segment longitudinal axis and the second tube segment longitudinal axis are spaced by a tube segment distance and are parallel to one another, and wherein the valve in the inlet tube and the valve in the outlet tube are arranged in the respective first tube segment.

9. A method for operating a measuring device with a flowmeter, a inlet tube and an outlet tube, wherein the flowmeter has a measuring tube connected to the inlet tube and to the outlet tube, wherein the inlet tube, the measuring tube and the outlet tube form a siphon, the siphon is aligned in respect to a vector of the gravitational field of the earth so that, when the medium initially flows through the siphon and then the flowing of the medium stops, the measuring tube is completely filled with stagnant medium, wherein the method has the following method steps: in a first method step, the medium is made to flow through the inlet tube, the measuring tube and the outlet tube and the flowmeter carries out measurements on the medium flowing in the measuring tube, in a second method step, flow of the medium through the inlet tube, the measuring tube and the outlet tube is stopped and the flowmeter carries out measurements on the stagnant medium in the measuring tube, and in a third method step, the accuracy of the measurement from the first method step is increased by using the measurement from the second method step.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1 shows an embodiment of a measuring device,

[0025] FIG. 2 is a cross-sectional view of inlet/outlet tube of the measuring device from Fig.,

[0026] FIG. 3 is a cross-sectional view of the measuring device from FIG. 1 with a 1 with a flowing medium,

[0027] FIG. 4, is a cross-sectional view of the measuring device from FIG. 1 when flow has stopped, and

[0028] FIG. 5 a flow chart of a method in accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0029] FIG. 1 shows the measuring device 1 with the flowmeter 2, the inlet tube 3, and the outlet tube 4, the flowmeter being a nuclear-magnetic flowmeter in this embodiment. The flowmeter 2 has a measuring tube 5 that is connected to the inlet tube 3 and to the outlet tube 4. In this embodiment, the measuring tube 5 is straight and has a measuring tube longitudinal axis 6 that is aligned orthogonally to the vector of the gravitational field 7 of the earth.

[0030] The inlet tube 3 and the outlet tube 4 in this embodiment are identically designed and shown in FIG. 2. They each have a first tube segment 8 with a first tube segment longitudinal axis 9, a second tube segment 10 with a second tube segment longitudinal axis 11, and a third tube segment 12. Thereby, each of the first tube segment 8 of the inlet tube 3 and of the outlet tube 4 is connected to the measuring tube 5, the first tube segment 8 and the second tube segment 10 are connected to one another by the third tube segment 12, and the first tube segment longitudinal axis 9 and the second tube segment longitudinal axis 11 are spaced along the vector of the gravitational field 7 of the earth by a tube segment distance d and are aligned parallel to one another. Furthermore, in this embodiment, the projection 13 of the first tube inner cross section surface 14 of the first tube segment 8 onto the projection plane 15 and the projection 16 of the second tube inner cross section surface 17 of the second tube segment 10 onto the projection plane 15 do not intersect in the projection plane 15. The projection plane 15 is thereby aligned along the vector of the gravitational field 7 of the earth.

[0031] In this embodiment of the measuring device 1, the valve 18 is arranged in the second tube segment 10 of the inlet tube 3 and the valve 19 is arranged in the second tube segment 10 of the outlet tube 4.

[0032] FIGS. 3 and 4 are cross-sectional views of the measuring device and show it in operation. In FIG. 3, the medium 20 flows first through the inlet tube 3, then through the measuring tube 5 and, finally, through the outlet tube 4. FIG. 4 shows the measuring device 1 when the flowing of the medium 20 has stopped. Regardless of the embodiment of the measuring device 1, the inlet tube 3, the measuring tube 5, and the outlet tube 4 form the siphon 21. The siphon 21 is thereby designed and aligned in respect to the vector of the gravitational field 7 of the earth so that, when the medium 20 initially flows through the siphon 21 and then the cause for the flowing of the medium 20 stops, the measuring tube 5 is completely filled with the stagnant medium 20.

[0033] The tube segment distance d between the first tube segment longitudinal axis 9 and the second tube segment longitudinal axis 11 is determined taking into account an assumed maximum flow velocity with assumed characteristics of the medium 20 so that, when the medium 20 initially flows through the inlet tube 3, the measuring tube 5, and the outlet tube 4 at the assumed maximum flow velocity, and then the cause for the flow of the medium 20 stops, the measuring tube 5 is completely filled with the stagnant medium 20.

[0034] Additionally, the third tube segment 12 of the inlet tube 3 and the third tube segment 12 of the outlet tube 4 are arranged slanted in respect to the vector of the gravitational field 7 of the earth so that the tube segments 12 form a ramp for the medium 20 in a direction opposite the vector of the gravitational field 7 of the earth, so that the medium 20 is decelerated.

[0035] The valves 18, 19 thereby control the flow of the medium 20 through the siphon 21. When the valves 18, 19 are open, the medium 20 flows through the measuring tube 5, and with the valves 18, 19 closed, flow in the measuring tube is stopped.

[0036] The measuring device 1 carries out the method shown in the flow chart in FIG. 5 during operation with the following method steps:

[0037] In the first method step 22, the medium 20 is made to flow through the inlet tube 3, the measuring tube 5, and the outlet tube 4 and the flowmeter 2 carries out measurements on the medium 20 flowing in the measuring tube 5. The flow of the medium 20 is thereby set by the opened valves 18, 19.

[0038] In the second method step 23, the medium 20 is not made to flow through the inlet tube 3, the measuring tube 5, and the outlet tube 4 and the flowmeter 2 carries out measurements on the stagnant medium 20 in the measuring tube 5. The medium 20 is not made to flow in that both valve 18 and valve 19 are closed.

[0039] In the third method step 24, the accuracy of the measurement from the first method step is increased by using the measurement from the second method step.