Methods of reducing the occurance of false positives in gas detectors

Patent metadata

Field	Value
Publication number	US-12282008-B2
Application number	US-202217805174-A
Country	US
Kind code	B2
Filing date	Jun 2, 2022
Priority date	Jul 14, 2021
Publication date	Apr 22, 2025
Grant date	Apr 22, 2025

Abstract

A method of indicating the presence of a target gas in a gas volume comprising providing a gas sensing core, configured for detection of the target gas, and a condition sensor within the gas volume, providing a controller, allowing gas to fluidly interact with the gas sensing core, monitoring a target gas measurement output from the gas sensing core, monitoring a parameter output from the condition sensor, recording a parameter output minimum value, calculating a parameter difference, calculating a rate of change of the parameter with respect to time, and indicating the presence of a target gas is detected in the gas volume when the target gas measurement exceeds a target gas measurement threshold value and the parameter difference is less than a parameter difference threshold value.

First claim

What is claimed is:

1. A method of indicating the presence of a target gas in a gas volume comprising:
providing a gas sensing core, configured for detection of the target gas, and a condition sensor within the gas volume,
providing a controller disposed in electrical communication with the gas sensing core and the condition sensor,
allowing gas within the gas volume to fluidly interact with the gas sensing core,
monitoring with the controller a target gas measurement output from the gas sensing core,
monitoring with the controller a parameter output from the condition sensor,
recording a parameter output minimum value in a memory of the controller,
calculating with the controller a parameter difference, wherein the parameter difference is the difference between the minimum value of the parameter and an instant value of the parameter,
calculating with the controller a rate of change of the parameter with respect to time, and
indicating the presence of a target gas is detected in the gas volume when the target gas measurement exceeds a target gas measurement threshold value and the parameter difference is less than a parameter difference threshold value.

2. The method of claim 1 , further comprising indicating the presence of a target gas is detected in the gas volume when the target gas measurement exceeds the target gas measurement threshold value, the parameter difference exceeds the parameter difference threshold value, and the rate of change of the parameter with respect to time is less than a rate threshold value.

3. The method of claim 2 , further comprising not indicating the presence of the target gas is detected in the gas volume when target gas measurement exceeds a target gas threshold value, the parameter difference exceeds the parameter difference threshold value, and the rate of change of the parameter with respect to time exceeds a rate threshold value.

4. The method of claim 1 , further comprising locating the gas sensing core and the condition sensor in an HVAC/R device, wherein the gas volume is adjacent a flammable refrigerant containing component of the HVAC/R device.

5. The method of claim 1 , wherein indicating a presence of the target gas comprises signaling to a system controller of a HVAC/R device that target gas is detected, activating an indicator light in electrical communication with the controller, annunciating an alarm through a speaker in electrical communication with the controller, or a combination comprising at least one of the foregoing.

6. The method of claim 1 , wherein the recording the parameter output minimum value further comprises recording the parameter output minimum value from the condition sensor over a timespan.

7. The method of claim 1 , wherein the calculating with the controller a rate of change of the parameter output with respect to time further comprises calculating the rate of change from the parameter output minimum value and a corresponding timestamp, to the instant parameter output and corresponding instant timestamp.

8. The method of claim 1 , wherein the condition sensor comprises a temperature sensor, or a humidity sensor.

9. The method of claim 1 , wherein the gas sensing core comprises a combustible gas sensor, a flammable gas sensor, a radon sensor, a smoke sensor, a carbon monoxide sensor, a hydrogen sulfide sensor, a particulate matter sensor, a volatile organic compound sensor, an oxygen sensor, a formaldehyde sensor, a lead sensor, a pesticide sensor, a nitrogen dioxide sensor, or a carbon dioxide sensor.

10. The method of claim 1 , wherein the target gas measurement threshold value is greater than or equal to 5% and less than or equal to 25% of the lower flammability limit of a flammable refrigerant contained within a flammable refrigerant containing component of a HVAC/R device.

11. The method of claim 1 , wherein the condition sensor comprises a temperature sensor, and wherein the parameter difference threshold value is greater than 2° C.

12. The method of claim 1 , wherein the condition sensor comprises a humidity sensor, and wherein the parameter difference threshold value is greater than 5% relative humidity.

13. The method of claim 1 , wherein the condition sensor comprises a temperature sensor, and wherein the rate threshold value is greater than 1.5° C./minute.

14. An HVAC/R system comprising:
a vapor compression device containing flammable refrigerant and a system controller,
a gas sensing module disposed in fluid communication with a gas volume surrounding at least a portion of the vapor compression device, wherein the gas sensing module comprises a gas sensing core configured to measure a target gas measurement output and a condition sensor configured to measure a parameter output,
a controller disposed in electrical communication with the system controller, the gas sensing core and the condition sensor, wherein the controller is configured to;
monitor a target gas measurement output from the gas sensing core;
monitor a parameter output from the condition sensor;
record a parameter output minimum value in the memory;
calculate a parameter difference, wherein the parameter difference is the difference between the minimum value of the parameter and an instant value of the parameter;
calculate a rate of change of the parameter with respect to time;
determine that a target gas is detected in the gas volume when the target gas measurement exceeds a target gas measurement threshold value, and the parameter difference is less than a parameter difference threshold value; and
initiate a control action in response to a determination that a target gas is detected by the gas sensing module.

15. An HVAC/R system comprising:
a vapor compression device containing flammable refrigerant and a system controller,
a gas sensing module disposed in fluid communication with a gas volume surrounding at least a portion of the vapor compression device, wherein the gas sensing module comprises a gas sensing core configured to measure a target gas measurement output and a condition sensor configured to measure a parameter output,
a controller disposed in electrical communication with the system controller, the gas sensing core, and the condition sensor, wherein the controller is configured to initiate a control action in response to a determination that a target gas is detected by the gas sensing module, wherein the determination of the gas sensing core is disregarded as erroneous when:
the target gas measurement exceeds a target gas measurement threshold value,
a parameter difference exceeds a parameter difference threshold value, wherein the parameter difference comprises a difference between the parameter output and a minimum parameter output value stored in a memory of the controller, and
a rate of change of the parameter with respect to time exceeds a rate threshold value, wherein the rate of change of the parameter with respect to time comprises the parameter difference divided by a timespan between the instant time and a timestamp of the minimum parameter output value was stored in the memory of the controller.

Assignees

• Carrier Corp

Inventors

• Xiong Ziyou
• Birnkrant Michael
• Piech Marcin

Classifications

• G01N33/0063

  using a threshold to release an alarm or displaying means · CPC title

• F24F11/36

  to leakage of heat-exchange fluid · CPC title

• F25B2500/222

  Detecting refrigerant leaks · CPC title

• F25B49/00

  Arrangement or mounting of control or safety devices · CPC title

• G01D21/02

  Measuring two or more variables by means not covered by a single other subclass · CPC title