# US 8,465,791 B2 · Method for counting particles in a gas

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- Number: US 8,465,791 B2
- Document ID: US8465791B2
- Status: Granted
- Kind: B2
- Application number: 12/872,697
- Filed: 2010-08-31
- Published: 2011-04-21
- Granted: 2013-06-18
- Earliest claimed: 2009-10-16
- Assignees: MSP Corporation
- Applicants: Benjamin Y. H. Liu; Thuc M. Dinh; William D. Dick; Aaron M. Collins; Francisco J. Romay
- Inventors: Benjamin Y. H. Liu; Thuc M. Dinh; William D. Dick; Aaron M. Collins; Francisco J. Romay
- Web page: https://patentgrep.com/patent/US8465791B2

## CPC

- B05C 11/00: Component parts, details or accessories not specifically provided for in groups B05C1/00 - B05C9/00 (means for manipulating or holding work B05C13/00; enclosures for apparatus, booths B05C15/00; spray booths B05B16/00)
- G01N 15/065: {using condensation nuclei counters}
- B05C: APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (spraying apparatus, atomising apparatus, nozzles B05B; plant for applying liquids or other fluent materials to objects by electrostatic spraying B05B5/08)
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

A method for detecting particles in a gas by saturating the gas with vapor and causing the gas to flow through a chamber with walls that are at a temperature different than the temperature of the entering gas creating a gas turbulence within the chamber resulting in the gas becoming super-saturated with vapor and causing said super-saturated vapor to condense on said particles and form droplets, which are then detected and counted by an optical light-scattering detector.

## Claims

### Claim 1

A method for creating a super-saturated vapor in a gas containing particles for detection, said method including: introducing said gas with vapor at a first temperature into a chamber having a second temperature different from the first temperature of the gas, the introduction of the gas into the chamber creating a gas flow that changes said first temperature of said gas and causes said gas to mix and create a super-saturated vapor for condensation on said particles to form droplets for detection.

### Claim 2 (depends on 1)

The method of claim 1, wherein said gas flow within the chamber being substantially circulatory.

### Claim 3 (depends on 1)

The method of claim 1, wherein the temperature of said gas entering said chamber is greater than the temperature of said chamber.

### Claim 4 (depends on 1)

The method claim 1, wherein vapor is added to said gas to bring said gas to substantial saturation before introducing said gas into said chamber.

### Claim 5 (depends on 1)

The method of claim 1, wherein the temperature of said gas entering the chamber is less than the temperature of said chamber, and wherein said temperature change of said gas in said chamber is accompanied by vapor addition to said gas in said chamber.

### Claim 6 (depends on 1)

The method of claim 1 including the additional step of introducing the gas through a flow restriction into a second chamber to cause the gas to undergo further mixing in said second chamber.

### Claim 7 (depends on 1)

The method of claim 1 wherein the gas is introduced into the chamber through a flow restriction to create a gas velocity sufficient to cause the gas to mix to create super-saturation and cause vapor to condense on particles to form droplets.

### Claim 8 (depends on 1)

The method of claim 1 wherein the vapor is water vapor.

### Claim 9 (depends on 1)

The method of claim 1 wherein the vapor comprises a chemical substance with a molecular weight that is higher than water and a vapor diffusivity that is lower than water.

### Claim 10

A method for creating a super-saturated vapor in a gas containing particles for detection, said method including: saturating said gas with vapor at a first temperature; introducing said gas into a first chamber, said first chamber being at a second temperature different from the first temperature resulting in the formation of a substantially laminar stream to change said temperature of said gas; and introducing said gas through a flow restriction into a second chamber to create turbulence in the second chamber thereby causing said gas to mix forming a super-saturated vapor for condensation on said particles to form droplets; and detecting said droplets so formed to detect said particles in said gas.