Flow meter for dosing pumps

A flow meter for a pulsed fluid stream which performs a succession of pulses, comprising:

• a flow sensor body defining an internal flow channel having an inlet and an outlet, the flow channel configured to allow flow of the fluid stream in a direction from said inlet to said outlet:
• a float structure movable in said flow channel in said direction by the pulsed stream and being biased to perform a movement counter to said direction between successive pulses of the fluid stream, the float structure comprising a float body and a ferromagnetic body:
• first, second and third coils surrounding first, second and third portions of the flow sensor body;
• the second coil configured as a drive coil for connection to an AC signal generator and situated between the first and third coils along the float body;
• each of said first and third coils configured to generate induced voltage signals in response to the position of said float structure in said flow channel;
• and
• an electronics module connected to the first, second and third coils, the electronics module including:
• the AC signal generator connected to the second coil to drive the second coil with AC signals;
• the module configured to measure the position of the float structure in said flow channel, the module responsive to the induced voltage signals from each of the first and third coils and configured to determine the first peak voltage of the first coil with the float structure at rest between pulses of the fluid stream and the third peak voltage of the third coil during each pulse of the fluid stream;
• the module configured to generate a flow meter signal indictive of a fluid flow quantity passed through the channel;
• and
• wherein the float structure comprises a plurality of elongated channels extending longitudinally along the periphery of the float body.

A method for measuring fluid flow of a pulsed fluid stream which performs a succession of pulses, comprising:

• providing a sensor body defining a flow channel for the flow of the fluid stream and having an inlet and an outlet;
• positioning a movable float structure in the flow channel and being biased to perform a movement counter to the direction of fluid flow between successive pulses of the fluid stream, the float structure comprising a ferromagnetic body;
• providing first, second and third coils surrounding first, second and third portions of the sensor body the second coil disposed between the first and third coils along the sensor body;
• driving the second coil with an AC signal to generate induced voltage signals in the first and third coils in response to the position of said float structure in said channel;
• and
• analyzing the induced voltage signals in the first and third coils to determine the peak voltage of the first coil with the float structure at rest between pulses and the peak voltage of the third coil during each pulse and generating a flow meter signal indictive of a fluid flow passed through the channel.