Filter status sensor device, method of use, and automatic replenishment system

An air filter comprising:

• a filter media;
• and
• an airflow sensor device, attached to the filter media, comprising:
• a sensor housing having a bypass conduit configured for air flow around (or bypassing) the filter media;
• a displaceable baffle, movably mounted within the bypass conduit;
• a magnetic field sensor, mounted within the sensor housing, configured to generate an output voltage;
• and
• an embedded processing system, mounted within the sensor housing and operatively connected to the magnetic field sensor, configured to determine a position of the displaceable baffle based on the output voltage generated by the magnetic field sensor;
• wherein the displaceable baffle progressively moves within the bypass conduit in response to changes to a pressure differential across the displaceable baffle in proportion to an accumulation of particulate matter on the filter media, and
• wherein the displaceable baffle is a magnetically-biased check valve.

An air handling system comprising:

• a fan configured to create a negative pressure within a system housing;
• an air filter having a filter frame circumscribing a filter media;
• and
• an airflow sensor device, attached to the filter media, comprising:
• a sensor housing having a bypass conduit configured for air flow bypassing the filter media that extends from a first side of the sensor housing to a second side of the sensor housing;
• a displaceable baffle, movably mounted within the bypass conduit, wherein the displaceable baffle is configured to move within the bypass conduit in response to a pressure differential across the displaceable baffle;
• a magnetic field sensor, mounted within the sensor housing, configured to generate an output voltage in proportion to a magnetic flux density of a magnetic field from an actuation magnet mounted on the displaceable baffle;
• and
• an embedded processing system, mounted within the sensor housing and operatively connected to the magnetic field sensor, configured to determine a position of
• the displaceable baffle based on the output voltage generated by the magnetic field sensor;
• wherein the displaceable baffle progressively moves within the bypass conduit in response to changes of a pressure differential across the filter in proportion to an accumulation of particulate matter on the filter media;
• and
• wherein the displaceable baffle is a magnetically-biased check valve.