Robert S Keys

US Patent:

20120036925, Feb 16, 2012

Filed:

Aug 9, 2011

Appl. No.:

13/206250

Inventors:

Robert S. Keys - Viola WI, US

Assignee:

SENTRY EQUIPMENT CORPORATION - Oconomowoc WI

International Classification:

G01F 1/69

US Classification:

7320425

Abstract:

A digital fluid flow meter for measuring fluid flow past a surface on one side of a wall including first and second reduced thickness areas in the wall spaced from one another, a first detector having a first temperature sensitive element thermally coupled to the first reduced thickness area to provide thermal transfer between fluid in contact with the surface and the first detector, a second detector comprising a second temperature sensitive clement thermally coupled to the second reduced thickness area of said wall to provide thermal transfer between fluid in contact with the surface and the second detector. The digital fluid flow meter includes means for sensing the temperature of the first and second temperature sensitive elements, first and second heating elements for heating the respective temperature sensitive elements proximate to the first and second detectors, respectively. The meter includes means for providing input power and control signals to the first and second heating elements and means for transmitting output signals from the temperature sensing means. The wall may be a tube having reduced diameter sections for improving the turndown ratio, total turndown and sensitivity of the digital fluid flow meter.