Method and apparatus for monitoring particles in a flowing gas
View Patent ↗A method and apparatus for monitoring particulate matter in a gas sample and the air quality associated therewith is provided.
1. A method for monitoring the mass flow of particles of a specified size fraction in a gas stream which comprises:
(a) contacting or passing near the first triboelectric probe with a flowing particle-laden gas to obtain a first signal that embodies particle mass flow rate information;
(b) charging particles in the particle-laden gas to produce a surface charge on the particles;
(c) impinging the charged particles upon or passing near a second triboelectric to produce a second signal representative of particle surface area; and
(d) analyzing the relationship between the first signal and the second signal to ascertain information concerning sizes of particles in the particle-laden gas.
2. The method of claim 1 , wherein the steps (a) through (c) are performed continuously over an interval of time.
3. The method of claim 1 , wherein the steps (a) through (c) are performed serially.
4. The method of claim 1 , wherein the particle-laden gas comprises air.
5. The method of claim 4 wherein the information concerning sizes of particles in the particle-laden gas includes a percentage of particles having nominal diameters less than a delimiting value.
6. The method of claim 5 , wherein the delimiting value is 2.5 microns.
7. The method of claim 1 , wherein the steps (a) through (c) are performed as passive monitoring steps that do not require motive means to actuate the particle-laden gas.
8. The method of claim 1 , further comprising a step of using motive means to actuate the particle-laden gas.
9. The method of claim 1 , wherein the particles comprise biological materials.
10. The method of claim 1 , wherein the particles comprise chemical materials.
11. The method of claim 1 , wherein the particles comprise inorganic materials.
12. A device for monitoring air quality, comprising:
a first triboelectric probe configured to produce a first signal when gas-borne particulates contact or pass close to the probe;
means for charging particles in a particle-laden gas, the means for charging being positioned to avoid impingement of charged particles on the first triboelectric probe, but also to charge essentially the same gas-borne particulates contacting the first triboelectric probe; and
a second triboelectric probe positioned such that charged particles produced by the means for charging contact or pass close to it and produce a second signal.
13. The device of claim 12 , wherein the first triboelectric probe, the means for charging, and the second triboelectric probe are positioned sequentially in that order.
14. The device of claim 12 , wherein the particle-laden gas affected by the charging means comprises air.
15. The device of claim 12 , further comprising sensor electronics configured to operate on the first signal and second signal to ascertain information about the gas-borne particulates.
16. The device of claim 15 , wherein the sensor electronics contain program instructions calibrating the device for biological materials.
17. The device of claim 15 , wherein the sensor electronics contain program instructions calibrating the device for organic materials.
18. The device of claim 15 , wherein the sensor electronics contain program instructions calibrating the device for inorganic materials.
19. The device of claim 15 wherein the information includes a percentage of particles having nominal diameters less than a delimiting value.
20. The device of claim 19 , wherein the delimiting value is 2.5 microns.
21. The device of claim 15 , wherein the sensor electronics are configured to determine a ratio of the first signal and the second signal to facilitate ascertaining the information.
22. The device of claim 12 , without motive means to actuate the particle-laden gas.
23. The device of claim 12 , further comprising motive means to actuate the particle-laden gas.