John F. Walker, JR
Electrician at Kingsley Ave, Pueblo, CO
License number
Colorado 6496
Issued Date
Mar 19, 1982
Renew Date
Feb 28, 1983
Expiration Date
Feb 28, 1983
Type
Journeyman Electrician
Address
Address
106 Kingsley Ave, Pueblo, CO 81005
Professional information
Independent Biotechnology Professional
Location:
Pueblo, Colorado Area
Industry:
Biotechnology
Education:
Arizona State University 1986 - 1990
Photoacoustic Instrument For Measuring Particles In A Gas
US Patent:
6662627, Dec 16, 2003
Filed:
Jun 22, 2001
Appl. No.:
09/888251
Inventors:
William Patrick Arnott - Reno NV
Hans Moosmuller - Reno NV
John W. Walker - Pueblo CO
Hans Moosmuller - Reno NV
John W. Walker - Pueblo CO
Assignee:
Desert Research Institute - Reno NV
International Classification:
G02N 2100
US Classification:
73 2402, 73 2406, 73 2801, 356438, 356440
Abstract:
A photoacoustic sensor that measures carbon black particles emitted in the exhaust gas of a vehicle traveling on a road or being tested on a dynamometer or engine stand. The sensor includes an acoustic waveguide and a pump mounted to an outlet of the waveguide. The pump pulls the gas through the waveguide. A critical orifice is mounted between the pump and the outlet. The critical orifice prevents noise generated by the pump from entering the waveguide. Optical windows are mounted at opposite ends of the waveguide. A modulated source of light is located adjacent one of the windows and irradiates the waveguide. A microphone is attached to the waveguide. The microphone detects an acoustic signal generated by absorption of the light by the particles in the gas. The acoustic signal is proportional to the mass concentration of particles in the gas. The microphone generates an electrical signal proportional to the acoustic signal.