Liquid conduction indication in a magnetic flowmeter
AssigneeRosemount Inc.
InventorsWilliam E. O'Donnell, Thomas P. Coursolle, David L. Wehrs
Life of this patent
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Abstract
A magnetic flowmeter with an improved liquid conduction indication has a flowtube assembly with a passage for liquid flow and has an electromagnet mounted outside the passage that provides ramped magnetic excitation. An electrode circuit couples through the passage and generates ramp spikes and a flow signal. A processor receiving the flow signal and generating a flow rate output. The processor also receives the ramp spikes and generates a filtered integral of the ramp spikes as a liquid conduction or empty pipe indication.
Claims28
A magnetic flowmeter with an improved liquid conduction indication, comprising:
- a flowtube assembly having a passage for liquid flow and having an electromagnet mounted outside the passage adapted to provide ramped magnetic excitation and having an electrode circuit coupling through the passage and generating ramp spikes and a flow signal;
- and
- a processor receiving the flow signal and generating a flow rate output;
- the processor further receiving the ramp spikes and generating a filtered integral of the ramp spikes as a liquid conduction indication.
A magnetic flowmeter with an improved liquid conduction indication, comprising:
- a flowtube assembly having a passage for liquid flow and having an electromagnet mounted outside the passage adapted to generate ramped magnetic excitation and having an electrode circuit coupling through the passage and generating ramp spikes and a flow signal;
- a converter having a buffer coupling to the electrode circuit and generating a buffer output, and having a flow output circuit receiving the buffer output and generating a flow rate output;
- a filter receiving the buffer output and selectively reproducing ramp spikes;
- and
- an integration circuit receiving the reproduced ramp spikes and generating an indication of liquid conduction in the passage.
A magnetic flowmeter with an improved liquid conduction indication, comprising:
- a flowtube assembly having a passage for liquid flow and having an electromagnet mounted outside the passage adapted to provide ramped magnetic excitation and having an electrode circuit coupling through the passage and generating ramp spikes and a flow signal;
- a processor receiving the flow signal and generating a flow rate output;
- and
- means for receiving the ramp spikes and generating a filtered integral of the ramp spikes as a liquid conduction indication.
Dependencies are inferred from the claim text.