CONTROL METHODS FOR SETTING A REFERENCE VOLTAGE IN AN AIR TREATMENT SYSTEM

• US 20140170955A1
• Filed: 02/21/2014
• Published: 06/19/2014
• Est. Priority Date: 07/14/2005
• Status: Active Grant

• Current Assignee: Access Business Group International LLC (Alticor Incorporated)
• Original Assignee: Access Business Group International LLC (Alticor Incorporated)
• Inventors: Niezgoda, Thomas A., Leppien, Thomas J., Evans, Gregory K.
• Granted Patent: US 9,568,210 B2
• Time in Patent Office: Days
• US Class Current: 454/256
• CPC Class Codes: B01D 2267/40 Different types of filters
• CPC Class Codes: B01D 46/0038 with means for influencing the odor, e.g. deodorizing substances
• CPC Class Codes: B01D 46/0086 Filter condition indicators
• CPC Class Codes: B01D 46/442 by measuring the concentration of particles
• CPC Class Codes: B01D 46/46 automatic
• CPC Class Codes: F24F 11/74 for controlling air flow rate or air velocity
• CPC Class Codes: G01N 21/53 within a flowing fluid, e.g. smoke

Abstract

A control system and associated methods for an air treatment system. In one aspect, the present invention provides a control system and method for controlling blower speed as a function of separately determined smoke and dust concentrations. In one embodiment, the control system and method provides a variable delayed between changes in motor speed to address undesirable rapid changes between speeds. In another aspect, the present invention provides a system and method for calibrating a sensor to provide more uniform operation over time. In yet another aspect, the present invention provide a system and method for calibrating motor speed to provide more consistent and uniform motor speed over time. The present invention also provides a system and method for tracking filter life by as a function of time, motor speed and/or a sensed variable, such as particulate concentration in the environment.

Claims

1. A method for controlling an air treatment system comprising:

providing a blower motor operable at first and second speed settings;

in response to a change in operation from the first speed setting to the second speed setting;

measuring the motor speed at recurring intervals over a time period,

determining an average measured speed over the time period,

comparing the average measured speed to a predetermined acceptable range for the second speed setting, and

adjusting the motor speed if the average measured speed falls outside of the predetermined acceptable range for the second speed setting,

wherein the steps of measuring, determining, comparing and adjusting are performed as part of a continuous control loop.

2. The method according to claim 1, wherein adjusting the motor speed includes varying a control signal to the blower motor.

3. The method according to claim 2, wherein the control signal includes a duty cycle, and wherein varying the control signal includes changing the duty cycle.

4. The method according to claim 3, further including storing the changed duty cycle to computer readable memory for subsequent iterations of the continuous control loop.

5. The method according to claim 1, further including determining the blower motor has continuously operated at the first speed setting for a minimum time period before commencing operation of the blower motor at the second speed setting.

6. The method according to claim 5, wherein the minimum time period is a variable time delay.

7. The method according to claim 6, wherein the variable time delay is manually adjustable.

8. A method for controlling an air treatment system, the method comprising:

providing a control signal to operate a blower motor at a first motor speed setting from among a plurality of motor speed settings;

modifying the control signal to operate the blower motor at a second motor speed setting from among the plurality of motor speed settings;

measuring motor speed in response to the change from the first motor speed setting to the second motor speed setting;

determining an average measured speed based on multiple measurements within a sample period;

comparing the average measured speed to a predetermined acceptable range for the second motor speed setting; and

adjusting the control signal if the average measured speed falls outside of the predetermined acceptable range for the second motor speed setting.

9. The method according to claim 8, wherein adjusting the control signal includes changing from a first duty cycle to a second duty cycle.

10. The method according to claim 9, further including assigning the second duty cycle to the second motor speed setting in computer readable memory.

11. The method according to claim 8 further including determining the blower motor has continuously operated at the first speed setting for a minimum time period before commencing operation of the blower motor at the second speed setting.

12. The method according to claim 11 wherein the minimum time period is a variable time delay.

13. The method according to claim 8, wherein measuring motor speed includes taking a plurality of motor speed readings from an RPM sensor.

14. The method according to claim 8, wherein the RPM sensor produces a pulse signal as a frequency indicative of motor speed.

15. A method for calibrating motor speed for a blower motor in an air treatment system, comprising the steps of:

providing a blower motor capable of operating at a plurality of motor speed settings;

predetermining an acceptable range of blower motor speeds for each of the plurality of motor speed settings;

in response to a motor speed setting change, taking a plurality of readings at predetermined intervals from a sensor indicative of motor speed;

computing a comparison value as a function of the readings, the comparison value being indicative of average motor speed over a period of time;

comparing the comparison value to the predetermined acceptable range for the corresponding motor speed setting;

adjusting the actual speed of the motor if the comparison value falls outside the predetermined acceptable range by a predetermined amount; and

repeating said taking, computing, comparing and adjusting steps until the comparison value falls within the predetermined acceptable range.

16. The method according to claim 15 further including determining the blower motor has continuously operated at one of the plurality of speed settings for a minimum time period before commencing the motor speed setting change.

17. The method according to claim 16 wherein the minimum time period includes a variable time delay.

18. The method according to claim 15, wherein adjusting the actual speed of the motor includes varying a control signal from an existing duty cycle to an updated duty cycle.

19. The method according to claim 18, further including saving the updated duty cycle to computer readable memory for retrieval after a power failure.

20. The method according to claim 15, wherein the steps of computing, comparing, adjusting and repeating are performed continuously.