Systems and methods for damper performance diagnostics

Patent metadata

Field	Value
Publication number	US-2016154405-A1
Application number	US-201615016239-A
Country	US
Kind code	A1
Filing date	Feb 4, 2016
Priority date	Mar 14, 2013
Publication date	Jun 2, 2016
Grant date	—

Abstract

A computerized method for conducting a performance diagnostic for a damper in a flow control unit includes providing a control signal to the 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 includes measuring a first differential pressure using a pressure sensor of the flow control unit at a first time before providing the control signal to the damper and measuring a second differential pressure using the pressure sensor of the flow control unit at a second time after providing the control signal to the damper. The method includes calculating a rate of change between the measured differential pressures based on a difference between the first and second measured differential pressures and a difference between the first and second times. The method includes predicting failure of the damper in response to the calculated rate of change being less than a threshold rate of change and outputting a damper failure prediction to at least one of a user interface device, a local memory, and communications electronics.

First claim

What is claimed is:

1 . A computerized method for conducting a performance diagnostic for a damper in a flow control unit, the method comprising:
providing a control signal to the 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; measuring a first differential pressure using a pressure sensor of the flow control unit at a first time before providing the control signal to the damper; measuring a second differential pressure using the pressure sensor of the flow control unit at a second time after providing the control signal to the damper; calculating a rate of change between the measured differential pressures based on a difference between the first and second measured differential pressures and a difference between the first and second times; predicting failure of the damper in response to the calculated rate of change being less than a threshold rate of change; and outputting a damper failure prediction to at least one of a user interface device, a local memory, and communications electronics.

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

3 . The method of claim 1 , further comprising:
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; determining that no flow is occurring through the flow control unit in response to the open differential pressure not exceeding the pressure threshold; and postponing the performance diagnostic in response to determining that no flow is occurring through the flow control unit.

4 . The method of claim 1 , further comprising:
instructing the damper to move into an open damper position and using a first measurement from the pressure sensor to determine an open differential pressure, wherein the first measurement is obtained after instructing the damper to move into the open position; instructing the damper to move into a closed damper position and using a second measurement from the pressure sensor to determine a closed differential pressure, wherein the second measurement is obtained after instructing the damper to move into the closed position; calculating a difference between the open differential pressure and the closed differential pressure; and diagnosing a stuck damper condition in response to the difference not exceeding a stuck damper pressure threshold.

5 . The method of claim 1 , wherein measuring the first differential pressure comprises:
instructing the damper to move into a first position; and using a first measurement from the pressure sensor to determine the first differential pressure, wherein the first measurement is obtained after instructing the damper to move into the first position.

6 . The method of claim 5 , wherein measuring the second differential pressure comprises:
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; and using a second measurement from the pressure sensor to determine the second differential pressure, wherein the second measurement is obtained at the end of the movement interval.

7 . The method of claim 6 , wherein calculating the rate of change comprises dividing a difference between the first differential pressure and the second differential pressure by a duration of the movement interval.

8 . The method of claim 1 , further comprising:
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; and diagnosing an improperly-sized damper condition in response to the difference exceeding a differential pressure threshold.

9 . The method of claim 8 , wherein diagnosing the improperly-sized damper condition comprises:
determining whether the measured differential pressure exceeds the expected differential pressure; 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 , further comprising:
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 conducting a performance diagnostic for a damper in a flow control unit, the system comprising:
a controller configured to provide a control signal to the 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; and a pressure sensor configured to measure a first differential pressure at a first time before providing the control signal to the damper and a second differential pressure at a second time after providing the control signal to the damper; wherein the controller is configured to:
calculate a rate of change between the measured differential pressures based on a difference between the first and second measured differential pressures and a difference between the first and second times;
predict failure of the damper in response to the calculated rate of change being less than a threshold rate of change; and
output a damper failure prediction 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 local controller for the flow control unit and configured to conduct the performance diagnostic using only differential pressure value as a measured variable.

13 . The system of claim 11 , wherein the controller is configured to:
instruct the damper to move into an open position; use 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; compare the open differential pressure to a pressure threshold; determine that no flow is occurring through the flow control unit in response to the open differential pressure not exceeding the pressure threshold; and postpone the performance diagnostic in response to determining that no flow is occurring through the flow control unit.

14 . The system of claim 11 , wherein the controller is configured to:
instruct the damper to move into an open damper position and u

Assignees

• Johnson Controls Tech Co

Inventors

• Goldschmidt Troy A
• Papadopoulos Dimitri S

Classifications

• G05B23/02

  Electric testing or monitoring · CPC title

• F24F2110/40

  Pressure, e.g. wind pressure · CPC title

• G05B2219/2614

  HVAC, heating, ventillation, climate control · CPC title

• F24F11/52

  Indication arrangements, e.g. displays · CPC title

• F24F11/32

  Responding to malfunctions or emergencies · CPC title