Systems and methods for detecting leaks in an electromagnetic flowmeter
An electromagnetic flowmeter has a flowtube configured to carry a conductive fluid. The flowtube has wall made of a conductive material. The wall has an inner surface surrounding a fluid flow path for the fluid. A non-conductive liner is positioned to electrically insulate the flowtube wall from the fluid. The flowtube and non-conductive liner define an electrode mounting hole. An electrode extends through the electrode mounting hole. The electrode and the non-conductive liner form a fluidic seal between the electrode mounting hole and the fluid flow path. At least a portion of the electrode is arranged in fluid communication with the flowtube within the electrode mounting hole. A short circuit detector can detect failure of the seal when conductive fluid that has leaked past the seal creates a short circuit as a result of the fluid communication between the flowtube and the electrode mounting hole.
1. An electromagnetic flowmeter comprising:
a flowtube configured to carry a flowing conductive fluid, the flowtube having a flowtube wall comprising a conductive material, the flowtube wall having an inner surface surrounding a fluid flow path for the conductive fluid;
a non-conductive liner positioned to electrically insulate the flowtube wall from the conductive fluid, the flowtube and non-conductive liner defining an electrode mounting hole;
an electrode extending through the electrode mounting hole, the electrode and the non-conductive liner forming a fluidic seal between the electrode mounting hole and the fluid flow path, at least a portion of the electrode being arranged in fluid communication with the flowtube within the electrode mounting hole.
2. The electromagnetic flowmeter of claim 1 wherein said portion of the electrode and a portion of the flowtube in the electrode mounting hole are in opposed relation free of obstruction therebetween.
3. The electromagnetic flowmeter of claim 1 further comprising a non-conductive spacer disposed around at least a portion of the electrode in the electrode mounting hole between the electrode and the flowtube wall, the non-conductive spacer having at least one fluidic path extending between the electrode and the flowtube wall so the conductive fluid can establish an electrical connection between the electrode and the flowtube wall in the event the conductive fluid leaks into the fluidic path.
4. The electromagnetic flowmeter of claim 3 wherein the non-conductive spacer comprises a cylindrically-shaped sleeve.
5. The electromagnetic flowmeter of claim 4 wherein the electrode comprises a head and a shank, the cylindrically-shaped sleeve having an axial hole configured to receive the shank.
6. The electromagnetic flowmeter of claim 5 wherein the fluidic path is a transverse hole in the cylindrically-shaped sleeve.
7. The electromagnetic flowmeter of claim 6 wherein the transverse hole extends from the shank to the flowtube wall.
8. The electromagnetic flowmeter of claim 1 further comprising a short circuit detector configured to detect whether conductive fluid is in the fluidic path.
9. The electromagnetic flowmeter of claim 8 where the short circuit detector is configured to detect current passing through the conductive fluid in the fluidic path.
10. The electromagnetic flowmeter of claim 8 wherein the short circuit detector is configured to detect a change in a resistance in an electrical path between the electrode and the flowtube wall.
11. The electromagnetic flowmeter of claim 8 wherein the short circuit detector is further configured to output an alarm when it detects the conductive fluid is in the fluidic path.
12. The electromagnetic flowtube of claim 1 wherein the electrode comprises a head and a shank, the head having a head diameter and the shank has a shank diameter and the head diameter is larger than the shank diameter.
13. The electromagnetic flowtube of claim 12 wherein the head comprises teeth configured to engage the non-conductive liner to help form the fluidic seal.
14. The electromagnetic flowtube of claim 1 wherein the fluidic path is configured so the conductive fluid establishes the electrical connection between the shank and the flowtube wall in the event that the conductive fluid leaks through the fluidic seal.