Air sampling system providing compound discrimination via comparative PID approach

• US 9,651,531 B2
• Filed: 06/28/2013
• Issued: 05/16/2017
• Est. Priority Date: 06/28/2013
• Status: Active Grant

• Current Assignee: Aircuity Incorporated
• Original Assignee: Aircuity Incorporated
• Inventors: Desrochers, Eric M.
• Primary Examiner(s): Caputo, Lisa
• Assistant Examiner(s): Roy, Punam
• Application Number:
  US13/930,017
• Publication Number:
  US 20150004898A1
• Time in Patent Office: 1,418 Days
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/36 to leakage of heat-exchange fluid
• CPC Class Codes: F24F 2110/50 Air quality properties
• CPC Class Codes: F24F 2110/66 Volatile organic compounds [VOC]
• CPC Class Codes: G01N 1/2226 Sampling from a closed space, e.g. food package, head space
• CPC Class Codes: G01N 27/66 and measuring current or voltage
• CPC Class Codes: G01N 33/0054 Ammonia
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

Methods and apparatus for providing an air sampling system with first and second PID sensors to discriminate ammonia measurements. In one embodiment, air samples are taken from a vivarium environment to determine ammonia levels for controlling air flow to the vivarium.

Claims

1. A method of providing a discriminating measurement of ammonia along with a limited number of secondary airborne parameters associated with animal waste from an indoor environment comprising:

obtaining an air sample by a multipoint air sampling system which contains a representative concentration of ammonia and said other secondary airborne parameters from said environment;

measuring said air sample by a higher photonic energy photoionization detector applied within said multipoint air sampling system to create a first photoionization detector signal;

measuring said air sample by a lower photonic energy photoionization detector applied within said multipoint air sampling system to create a second photoionization detector signal; and

generating a PID measurement derived from the said second photoionization detector signal and said first photoionization detector signal by subtracting the second photoionization detector signal from the first photoionization detector signal, wherein the PID measurement is proportional to the second photoionization detector signal subtracted from the first photoionization detector signal.

2. The method according to claim 1 wherein the PID measurement includes an enhanced response factor to compensate for said second photoionization detector finite response to ammonia.

3. The method of claim 1, wherein the multipoint air sampling system comprises a star configuration system.

4. The method of claim 1, wherein the multipoint air sampling system comprises a networked air sampling system.

5. The method of claim 1 wherein the higher photonic energy photoionization detector has a 10.6 eV lamp and the lower photonic energy photoionization detector has a 10.0 eV lamp.

6. The method of claim 1 wherein the indoor environment is a vivarium.

7. The method of claim 1, wherein the indoor environment comprises cage racks.

8. The method of claim 1 wherein the indoor environment is an exhaust duct connected to a cage rack which is monitored by said multipoint sampling system in order to keep track of the environmental conditions of the cages.

9. The method of claim 8, wherein the PID measurement is used to optimize the cage bedding change schedule.

10. An air sampling system, comprising:

an air sample by a multipoint air sampling system to obtain air samples;

a sensor suite including a higher photonic energy photoionization detector to create a first photoionization detector signal and a lower photonic energy photoionization detector to create a second photoionization detector signal; and

a processor to generate a PID measurement from said second photoionization detector signal and said first photoionization detector signal to discriminate ammonia by subtracting the second photoionization detector signal from the first photoionization detector signal, wherein the PID measurement is proportional to the second photoionization detector signal subtracted from the first photoionization detector signal.

11. The air sampling system according to claim 10, wherein the air samples are obtained from a vivarium environment.

12. The air sampling system according to claim 11, wherein the PID measurement is used to generate an air flow signal to control air flow to the vivarium environment.

13. The air sampling system according to claim 11, wherein the PID measurement is used to derive a schedule to change animal bedding material.

14. The air sampling system according to claim 10, wherein the higher photonic energy photoionization detector has a 10.6 eV lamp and the lower photonic energy photoionization detector has a 10.0 eV lamp.