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

• US 20130197829A1
• Filed: 01/31/2012
• Published: 08/01/2013
• Est. Priority Date: 01/31/2012
• Status: Active Grant

• Current Assignee: Clean Alert Innovations LLC (Jeffrey M. Gross)
• Original Assignee: William Sherman III
• Inventors: Sherman, William III, Green, Richard
• Granted Patent: US 9,186,609 B2
• Time in Patent Office: Days
• US Class Current: 702/45
• 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 first gas flow, comprising:

a sensing system for measuring a property within the conduit, wherein a condition of the gas filter affects the value of the measured property;

a controller including a processor, a memory for storing electronic information therein, and program instructions for obtaining a first measurement of the property when the gas filter is in a first state, for obtaining a second measurement of the property when the gas filter is in a second state, and for comparing the first measurement and the second measurement; 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 measurement is validated by making a determination chosen from the group verify blower on when second measurement obtained, verify blower at stable operating speed when second measurement obtained, and verify blower operating at same speed as when the second measurement was obtained relative to previous monitoring event.

3. The system of claim 1, further comprising indicator means capable of sending at least one signal indicating a condition of the gas filter, the indication being based on the difference between the first measurement and the second measurement.

4. The system of claim 1, further comprising:

a sensing tube having an outlet in fluid communication with an interior of the gas conduit, the gas conduit being at least partially hollow;

a first sensor linked with a heater arranged to provide energy to the first sensor;

a second sensor for sensing a first temperature, the first sensor and second sensor being positioned inside the sensing tube and exposed to gas flowing through the sensing tube,

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 a fixed number of degrees above the first temperature.

5. The system of claim 4, wherein the temperature of the first sensor is raised by no more than about 5°

C. above the first temperature.

6. The system of claim 5, in which air flow velocity in the gas conduit is not directly measured.

7. The system of claim 5, in which the speed of the gas blower is not directly sensed.

8. The system of claim 1, the processor further being configured to compare the difference between the first measurement and the second measurement to a clog threshold.

9. The system of claim 8, the processor further being configured to recalculate the clog threhold in response to changes in fan speed of the gas blower.

10. The system of claim 4, further comprising a thermal insulator between the first sensor and the interior of the gas conduit.

11. A clogging detection method for use with a gas filter in a gas conduit that is at least partially hollow and operatively attached to a gas blower having power to produce a first gas flow, comprising:

providing a sensing system for the gas conduit;

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;

taking a second measurement of the property when the gas filter is in a second state; and

configuring a controller, having a processor, a memory for storing electronic information therein, and program instructions, to compare the first measurement and the second measurement, and validate the second measurement.

12. The method of claim 11, further comprising configuring the controller to obtain the first measurement and the second measurement, store the first measurement in memory, and compare the first measurement and the second measurement.

13. The method of claim 12, wherein the second measurement is validated by making a determination chosen from the group verify blower on when second measurement obtained, verify blower at stable operating speed when second measurement obtained, and verify blower operating at same speed as when the second measurement was obtained relative to previous monitoring event.

14. The method of claim 12, further comprising configuring the controller to calculate a threshold for indicating whether a difference between the first measurement and the second measurement is within a range of values consistent with the second state being that of a clogged gas filter.

15. The method of claim 14, further comprising configuring the controller to send at least one signal indicating a condition of the gas filter, the indication being based on the comparison of the first measurement to the second measurement.

16. The method of claim 12, further comprising the steps of:

providing a sensing tube having a first sensor coupled to a heater and a second sensor for measuring gas temperature within the sensing tube;

the sensing tube having an outlet in fluid communication with an interior of the gas conduit; and

a heater for raising the temperature of the first sensor a fixed amount above the temperature measured by the second sensor,

wherein the measured property is voltage for raising the temperature of the first sensor.

17. The method of claim 16, wherein the temperature of the first sensor is raised by no more than about 5 °

C. above the first temperature.

18. The method of claim 14, wherein the controller is further configured to recalculate the threshold in response to changes in fan speed of the gas blower.

19. A computer program product comprising computer readable instructions stored on a memory medium, the program product for use with a filter clog detection system of the type that includes:

at least one sensor;

at least one sensing tube having an outlet in fluid communication with an interior of a gas conduit, the gas conduit being at least partially hollow, and

a controller having a memory and program instructions,

wherein the controller is configured to;

obtain a first measurement of a property when the gas filter is in a first state,

obtain a second measurement of the property when the gas filter is in a second state,

and compare the difference between the first measurement and the second measurement and validate the second measurement.

20. The computer program product of claim 19, wherein the second measurement is validated by making a determination chosen from the group verify blower on when second measurement obtained, verify blower at stable operating speed when second measurement obtained, and verify blower operating at same speed as when the second measurement was obtained relative to previous monitoring event.

21. The computer program product of claim 19, wherein the program product is for use with a filter clog detection system that further includes:

a temperature sensor for sensing a first temperature,

wherein the at least one sensor is a heated sensor coupled with a heater arranged to provide energy to the heated sensor,

the heated sensor and the temperature sensor being positioned inside the sensing tube and exposed to gas flowing through the sensing tube,

the first temperature being the temperature of a flow of gas in the sensing tube, and

the heater being further arranged to raise the temperature of the first sensor to a second temperature.

22. The computer program product of claim 21, wherein the second temperature is no more than about 5°

C. above the first temperature, and the property includes a reading indicative of voltage provided by the heater to the first sensor.