Gas sensors

Details Gas sensors Gas sensors

2007-07-10

2007-07-10

Nguyen, Sang H. (Department: 2877)

Optics: measuring and testing

For light transmission or absorption

Of fluent material

C356S432000, C356S433000, C250S343000, C250S339040, C073S024020

Reexamination Certificate

active

11408363

ABSTRACT:
The present invention relates to a device for accomplishing noise reduction in a photoacoustic gas detector using a sound damping element and/or a background or reference microphone where a preferably larger external volume that acts as a sound damping element (SDE) is coupled to a smaller volume through which the gas diffuses. The coupling is accomplished in such a way that the externally generated sound waves incident upon the photoacoustic detector are adequately attenuated by the larger volume SDE without adversely affecting diffusion of the gaseous species of interest through the smaller volume for measurement by the detector. Preferably this is accomplished by coupling the larger SDE volume to the smaller gas diffusion volume by a long and thin pressure channel. Another photoacoustic detector includes a measuring system to measure the photoacoustic excitation of analyte gas entering the photoacoustic detector, a reference system to measure the effect of pressure waves in the environment, and a system for offsetting an output from the measuring system with an output from the reference system to reduce noise resulting from pressure waves in the environment in an output signal of the photoacoustic detector. The present invention also relates to a device for testing the integrity of a porous member and includes a source of pressure waves and a sensor for measuring a signal resulting from the transmittal of pressure waves from the transmitter. The signal is proportional to pressure losses through the porous member. The pressure losses through the porous member are, in turn, a measure of the degree to which the porous member has become clogged.

REFERENCES:
patent: 4436428 (1984-03-01), Watanabe et al.
patent: 4622845 (1986-11-01), Ryan et al.
patent: 5616826 (1997-04-01), Pellaux et al.
patent: 6006585 (1999-12-01), Forster
patent: 6049728 (2000-04-01), Chou

Affiliated with

Also associated with

Rating

Gas sensors does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Gas sensors, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Gas sensors will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3821615