Filter clog sensing system and method for compensating in response to blower speed changes

• US 9,186,609 B2
• Filed: 01/31/2012
• Issued: 11/17/2015
• Est. Priority Date: 01/31/2012
• Status: Active Grant

• Current Assignee: Clean Alert Innovations LLC (Jeffrey M. Gross)
• Original Assignee: Cleanalert, LLC
• Inventors: Sherman, William III, Green, Richard
• Primary Examiner(s): SUGLO, JANET L
• Application Number:
  US13/363,361
• Publication Number:
  US 20130197829A1
• Time in Patent Office: 1,386 Days
• Field of Search: 702/45
• US Class Current: 1/1
• CPC Class Codes: B01D 46/0086 Filter condition indicators
• CPC Class Codes: F24F 11/39 Monitoring filter performance

Abstract

A sensing system and method for use with a gas filter in a gas conduit attached to a gas blower, having a motor for producing a first gas flow blower speed, discards readings taken when the blower is off or during blower startup and shutdown, and recalculates a clog threshold in response to changes in the fan speed of a multi-speed blower.

Claims

1. A filter clog detection system for a gas filter in a gas conduit operatively attached to a gas blower having power to produce a gas flow, comprising:

a sensing system that measures a property within the conduit based upon a flow of gas into the sensing system from outside the gas conduit, wherein a condition of the gas filter affects the value of the measured property;

a controller, including a memory that stores electronic information therein and a processor executing program instructions, that obtains a first measurement of the property when the gas filter is in a first state, obtains a second measurement of the property when the gas filter is in a second state, and compares the first measurement and the second measurement;

wherein the sensing system comprises a sensing tube formed with an opening at two ends, and a plate attached to the sensing tube, the sensing tube having an inlet as one of the openings that receives gas flow from outside the gas conduit, and an outlet as the other opening that allows gas to flow into the gas conduit;

wherein the sensing system further comprises a first sensor linked with a heater that provides energy to the first sensor;

a second sensor that senses a first temperature within the sensing tube, wherein the first sensor and second sensor are positioned inside the sensing tube and exposed to gas flowing through the sensing tube, wherein the heater increases voltage to the first sensor as air velocity moving through the sensing tube increases;

wherein the first temperature is the temperature of gas in the sensing tube, and the measured property is the voltage for raising the temperature of the first sensor to a second temperature that is a fixed number of degrees above the first temperature; and

processor means for comparing the difference between the first measurement and the second measurement to a stored value in order to validate the second measurement.

2. The system of claim 1, wherein the second temperature is raised by no more than about 5°

C. above the first temperature.

3. The system of claim 1, wherein the controller discards the second measurement if the blower is off or is not operating at a stable operating speed.

4. The system of claim 1, wherein the controller determines if a change in fan speed of the gas blower at the time of the second monitoring event compared to a previous monitoring event exceeds a fan speed change threshold.

5. The system of claim 1, wherein the processor compares the difference between the first measurement and the second measurement to a clog threshold.

6. The system of claim 5, wherein the processor recalculates the clog threshold in response to changes in fan speed of the gas blower.

7. A clogging detection method for a gas filter in a conduit operatively attached to a gas blower having power to produce a gas flow comprising:

providing a sensing tube having a first sensor coupled to a heater and a second sensor that senses a first temperature within the sensing tube when gas is flowing from outside the conduit into the sensing tube, wherein the sensing tube introduces gas flow into the gas conduit with an inlet that receives gas flow from outside the gas conduit, and an outlet that allows gas to flow into the gas conduit;

providing energy from the heater to the first sensor to raise the temperature to a second temperature, which is a fixed number of degrees above the temperature measured by the second sensor, and wherein as air velocity moving through the sensing tube increases the heater increases voltage to the first sensor to raise the temperature of the first sensor;

obtaining a first measurement to determine a property within the conduit when the gas filter is in a first state, wherein a condition of the gas filter affects the value of the measured property;

obtaining a second measurement of the property when the gas filter is in a second state, wherein the first measurement an second measurement are voltage for raising the temperature of the first sensor to a second temperature that is a fixed number of degrees above the first temperature; and

configuring a controller, having a memory that stores electronic information therein and a processor executing program instructions, to store and compare the first measurement and the second measurement, and to validate the second measurement by comparing the second measurement to a previous monitoring event to verify the blower is on and is operating at a stable operating speed.

8. The method of claim 7, wherein the temperature of the first sensor is raised by no more than about 5°

C. above the first temperature.

9. The method of claim 7, wherein the controller recalculates the threshold in response to changes in fan speed of the gas blower.

10. The method of claim 7, further comprising determining if a change in fan speed of the gas blower compared to a previous monitoring event exceeds a fin speed change threshold.