SYSTEMS AND METHODS FOR DAMPER PERFORMANCE DIAGNOSTICS

• US 20140277773A1
• Filed: 03/14/2013
• Published: 09/18/2014
• Est. Priority Date: 03/14/2013
• Status: Active Grant

• Current Assignee: Tyco Fire & Security GmbH (Johnson Controls International plc)
• Original Assignee: Johnson Controls Technology Company (Johnson Controls International plc)
• Inventors: Goldschmidt, Troy A., Papadopoulos, Dimitri S.
• Granted Patent: US 9,279,596 B2
• Time in Patent Office: Days
• US Class Current: 700/282
• CPC Class Codes: F24F 11/32 Responding to malfunctions or emergencies
• CPC Class Codes: F24F 11/52 Indication arrangements, e.g. displays
• CPC Class Codes: F24F 11/74 for controlling air flow rate or air velocity
• CPC Class Codes: F24F 2110/40 Pressure, e.g. wind pressure
• CPC Class Codes: F24F 2140/40 Damper positions, e.g. open or closed
• CPC Class Codes: G01F 1/36 the pressure or differential pressure being created by the use of flow constriction
• CPC Class Codes: G01F 25/00 Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume
• CPC Class Codes: G01F 25/10 of flowmeters
• CPC Class Codes: G05B 13/026 using a predictor
• CPC Class Codes: G05B 2219/2614 HVAC, heating, ventillation, climate control
• CPC Class Codes: G05B 23/02 Electric testing or monitoring
• CPC Class Codes: G05B 23/0205 by means of a monitoring system capable of detecting and responding to faults

Abstract

A computerized method for diagnosing a damper condition in a flow control unit includes providing a control signal to a damper. The control signal instructs the damper to move into a target position or to achieve a target flow rate through the flow control unit. The method further includes receiving pressure information including one or more pressure measurements from a differential pressure sensor of the flow control unit and using the pressure information and the control signal to conduct a damper performance diagnostic. The damper performance diagnostic includes at least one of: a stuck damper diagnostic, a predictive damper failure diagnostic, an improperly-sized damper diagnostic, and a damper leakage diagnostic.

Claims

1. A computerized method for diagnosing a damper condition in a flow control unit, the method comprising:

providing a control signal to a damper, wherein the control signal instructs the damper to move into a target position or to achieve a target flow rate through the flow control unit;

obtaining a differential pressure value using a measurement from a pressure sensor of the flow control unit;

using the differential pressure value and the control signal to conduct a damper performance diagnostic process including at least one of;

a stuck damper diagnostic process, a predictive damper failure diagnostic process, an improperly-sized damper diagnostic process, and a damper leakage diagnostic process; and

outputting a result of the damper performance diagnostic process to at least one of;

a user interface device, a local memory, and communications electronics.

2. The method of claim 1, wherein the damper performance diagnostic is conducted by a local controller for the flow control unit using only the differential pressure value as a measured variable.

3. The method of claim 1, wherein the damper performance diagnostic process comprises:

instructing the damper to move into an open position;

using a measurement from the pressure sensor to determine an open differential pressure, wherein the measurement is obtained after instructing the damper to move into the open position;

comparing the open differential pressure to a pressure threshold; and

determining that no flow is occurring through the flow control unit in response to the open differential pressure not exceeding the pressure threshold.

4. The method of claim 3, wherein, in response to a determination that no flow is occurring, the damper performance diagnostic process further comprises:

updating the open differential pressure using an updated measurement from the pressure sensor; and

repeating the ‘

comparing,’

‘

determining,’ and

‘

updating’

steps until the open differential pressure exceeds the pressure threshold.

5. The method of claim 1, wherein the stuck damper diagnostic process comprises:

instructing the damper to move into a first position and using a first measurement from the pressure sensor to determine a first differential pressure, wherein the first measurement is obtained after instructing the damper to move into the first position;

instructing the damper to move into a second position and using a second measurement from the pressure sensor to determine a second differential pressure, wherein the second measurement is obtained after instructing the damper to move into the second position;

calculating a difference between the first differential pressure and the second differential pressure; and

diagnosing a stuck damper condition in response to the difference not exceeding a stuck damper pressure threshold.

6. The method of claim 5, wherein the first position is an open damper position and the second position is a closed damper position.

7. The method of claim 1, wherein the predictive damper failure diagnostic process comprises:

instructing the damper to move into a first position and using a first measurement from the pressure sensor to determine a first differential pressure, wherein the first measurement is obtained after instructing the damper to move into the first position;

instructing the damper to move from the first position toward a second position, wherein a time at which the damper begins moving defines a beginning of a movement interval and a time at which the damper stops moving defines an end of the movement interval;

using a second measurement from the pressure sensor to determine a second differential pressure, wherein the second measurement is obtained at the end of the movement interval;

calculating a rate of change between the determined differential pressures by dividing a difference between the first differential pressure and the second differential pressure by a duration of the movement interval;

calculating a difference between the calculated rate of change and an expected rate of change; and

predicting a damper failure in response to the difference between the calculated rate of change and the expected rate of change exceeding a threshold rate of change.

8. The method of claim 1, wherein the improperly-sized damper diagnostic process comprises:

receiving a damper size parameter;

instructing the damper to move into an operating position and using a measurement from the pressure sensor to determine a measured differential pressure, wherein the measurement is obtained after instructing the damper to move into the operating position;

estimating an expected differential pressure based on the damper size parameter and the operating position;

calculating a difference between the measured differential pressure and the expected differential pressure;

diagnosing an improperly-sized damper condition in response to the difference exceeding a differential pressure threshold.

9. The method of claim 8, wherein diagnosing an improperly-sized damper condition comprises:

determining whether the measured differential pressure exceeds the expected differential pressure; and

one of;

diagnosing that the damper size parameter is undersized in response to the measured differential pressure exceeding the expected differential pressure, and

diagnosing that the damper size parameter is oversized in response to the measured differential pressure not exceeding the expected differential pressure.

10. The method of claim 1, wherein the damper leakage diagnostic process comprises:

instructing the damper to move into a closed position and using a measurement from the pressure sensor to determine a closed differential pressure, wherein the measurement is obtained after instructing the damper to move into the closed position;

comparing the closed differential pressure to a differential pressure threshold; and

diagnosing an excessive leakage damper condition in response to the closed differential pressure exceeding a differential pressure threshold.

11. A system for diagnosing a damper condition in a flow control unit, the system comprising:

a pressure sensor configured to obtain one or more pressure measurements in the flow control unit; and

a controller configured to obtain a differential pressure value using the one or more pressure measurements and to provide a control signal to a damper, wherein the control signal instructs the damper to move into a target position or to achieve a target flow rate through the flow control unit,

wherein the controller is further configured to use the differential pressure value and the control signal to conduct a damper performance diagnostic process including at least one of;

a stuck damper diagnostic process, a predictive damper failure diagnostic process, an improperly-sized damper diagnostic process, and a damper leakage diagnostic process;

wherein the controller is further configured to output a result of the damper performance diagnostic process to at least one of;

a user interface device, a local memory, and communications electronics.

12. The system of claim 11, wherein the controller is a local controller for the flow control unit and wherein the damper performance diagnostic process uses only the differential pressure value as a measured variable.

13. The system of claim 11, wherein the damper performance diagnostic process comprises the steps of:

instructing the damper to move into an open position;

using a measurement from the pressure sensor to determine an open differential pressure, wherein the measurement is obtained after instructing the damper to move into the open position;

comparing the open differential pressure to a pressure threshold; and

determining that no flow is occurring through the flow control unit in response to the open differential pressure not exceeding the pressure threshold.

14. The system of claim 13, wherein, in response to a determination that no flow is occurring, the damper performance diagnostic process further comprises the steps of:

updating the open differential pressure using an updated measurement from the pressure sensor; and

repeating the ‘

comparing,’

‘

determining,’ and

‘

updating’

steps until the open differential pressure exceeds the pressure threshold.

15. The system of claim 11, wherein the stuck damper diagnostic process comprises the steps of:

instructing the damper to move into a first position and using a first measurement from the pressure sensor to determine a first differential pressure, wherein the first measurement is obtained after instructing the damper to move into the first position;

instructing the damper to move into a second position and using a second measurement from to pressure sensor to determine a second differential pressure, wherein the second measurement is obtained after instructing the damper to move into the second position;

calculating a difference between the first differential pressure and the second differential pressure; and

diagnosing a stuck damper condition in response to the difference not exceeding a stuck damper pressure threshold,

wherein the first position is an open damper position and the second position is a closed damper position.

16. The system of claim 11, wherein the predictive damper failure diagnostic process comprises the steps of:

instructing the damper to move into a first position and using a first measurement from the pressure sensor to determine a first differential pressure, wherein the first measurement is obtained after instructing the damper to move into the first position;

instructing the damper to move from the first position toward a second position, wherein a time at which the damper begins moving defines a beginning of a movement interval and a time at which the damper stops moving defines an end of the movement interval;

using a second measurement from the pressure sensor to determine a second differential pressure, wherein the second measurement is obtained at the end of the movement interval;

calculating a rate of change between the determined differential pressures by dividing a difference between the first differential pressure and the second differential pressure by a duration of the movement interval;

calculating a difference between the calculated rate of change and an expected rate of change; and

predicting a damper failure in response to the difference between the calculated rate of change and the expected rate of change exceeding a threshold rate of change.

17. The system of claim 11, wherein the improperly-sized damper diagnostic process comprises the steps of:

receiving a damper size parameter;

instructing the damper to move into an operating position and using a measurement from the pressure sensor to determine a measure differential pressure, wherein the measurement is obtained after instructing the damper to move into the operating position;

estimating an expected differential pressure based on the damper size parameter and the operating position;

calculating a difference between the measured differential pressure and the expected differential pressure;

diagnosing an improperly-sized damper condition in response to the difference exceeding a differential pressure threshold.

18. The system of claim 17, wherein diagnosing an improperly-sized damper condition comprises the steps of:

determining whether the measured differential pressure exceeds the expected differential pressure; and

one of;

diagnosing that the damper size parameter is undersized in response to the measured differential pressure exceeding the expected differential pressure, and

diagnosing that the damper size parameter is oversized in response to the measured differential pressure not exceeding the expected differential pressure.

19. The system of claim 11, wherein the damper leakage diagnostic process comprises the steps of:

instructing the damper to move into a closed position and using a measurement from the pressure sensor to determine a closed differential pressure, wherein the measurement is obtained after instructing the damper to move into the closed position;

comparing the closed differential pressure to a differential pressure threshold; and

diagnosing an excessive leakage damper condition in response to the closed differential pressure exceeding a differential pressure threshold.

20. One or more non-transitory computer-readable media having instructions for diagnosing a damper condition in a flow control unit stored therein, the instructions being executable by one or more processors to cause the one or more processors to perform operations comprising:

providing a control signal to a damper, wherein the control signal instructs the damper to move into a target position or to achieve a target flow rate through the flow control unit;

obtaining a differential pressure value using a measurement from a pressure sensor of the flow control unit;

using the differential pressure value and the control signal to conduct a damper performance diagnostic process including at least one of;

a stuck damper diagnostic process, a predictive damper failure diagnostic process, an improperly-sized damper diagnostic process, and a damper leakage diagnostic process; and

outputting a result of the damper performance diagnostic process to a user interface device,

wherein the damper performance diagnostic is conducted by a local controller for the flow control unit using only the differential pressure value as a measured variable.