The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 27, 2004
Filed:
May. 23, 2002
Mikhail Belenkii, San Diego, CA (US);
Trex Enterprises Corporation, San Diego, CA (US);
Abstract
An optical flow monitor. Fluid flow is determined by correlating two interference signals produced by coherent laser beams passing through a flowing fluid at two spaced-apart paths. The distance between the two paths is known and the correlation of the two signals is used to determine the time required for the fluid to flow between the two paths. In a preferred embodiment actually built and tested by Applicant the correlation is made by having an operator monitor on an oscilloscope the intensities of interference fringes corresponding to each of the two beam paths. Intensity variations in the interference fringes are caused by the same turbulent eddies passing each of the two paths. These turbulent eddies cause fluctuations in the index of refraction of the fluid which produce similar patterns on the oscilloscope which are separated on the oscilloscope time scale by an amount corresponding to the distance between the two beam paths and the flow rate of the fluid. The operator can determine the time difference between the similar patterns in the two beams and knowing the actual distance between the beams the operator can calculate the flow rate. In preferred embodiments the interference signals are produced using shear plates. In one preferred embodiment useful for monitoring the flow rate of a respirator, the correlation of the fringe intensity values corresponding to the two beam paths is made by a digital computer programmed with an algorithm for making cross correlation analyses that utilizes a fast Fourier transform.