US5728949A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fluid flow rate measuring circuit
Assignee: McMillan Co
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Filing: 1996-04-12
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Granted: 1998-03-17
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Expires: 2016-04-12
Abstract
Abstract A turbine wheel flow measuring transducer is provided for measuring low flow rates of corrosive fluids, whether fluids or gases. The transducer has a turbine wheel rotating in a housing fluid chamber at a rate set by the corrosive fluid flowing through the housing. Infrared light passing through the fluid is sensed and converted by an optical flow measurement circuit. The amount of light which passes through a rotating turbine wheel indicates flow rate. A processing circuit forms output signals indicative of fluid flow rate.
Inventors
- 👤 Robert D. McMillan
- 👤 Robert M. McMillan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:48
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/05; G01F1/06; G01F1/065; G01F15/00; G01F15/006; G01F15/02; G01F15/028
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
70 words
An optical flow measurement circuit for forming an electrical signal indicative of fluid flow, comprising: a light source mounted for emitting light to pass through the fluid; a light detector in optical alignment with said light source to sense the amount of light passing through the fluid; and a pulsed power source for energizing said light source at a duty cycle of about ten percent to thereby reduce power consumption.
Claim 2
Dependent Claim
70 words
An optical flow measurement circuit for forming an electrical signal indicative of fluid flow, comprising: a light source mounted for emitting light to pass through the fluid; a light detector in optical alignment with said light source to sense the amount of light passing through the fluid; and a pulsed power source for energizing said light source at a duty cycle of about ten percent to thereby reduce power consumption.
Claim 3
Dependent Claim
19 words
The measurement circuit of claim 1, wherein the fluids are corrosive fluids at low flow rates and pressure drops.
Claim 4
Dependent Claim
29 words
The measurement circuit of claim 2, wherein said flow rates of the corrosive fluids are on the order of twenty milliliters per minute to ten thousand milliliters per minute.
Claim 5
Dependent Claim
30 words
The measurement circuit of claim 2, wherein said pressure drops of the corrosive fluids are on the order of about twenty inches of water pressure or less for corrosive gases.
Claim 6
Dependent Claim
22 words
The measurement circuit of claim 1, wherein: said light source emits infrared light at a wavelength of about 0.9 to 1.1 microns.
Claim 7
Dependent Claim
21 words
The measurement circuit of claim 1, further including: a processing circuit for forming an output signal indicative of fluid flow rate.
Claim 8
Dependent Claim
24 words
The measurement circuit of claim 6, wherein said processing circuit includes: an amplifier forming a group of pulses in response to flow of fluid.
Claim 9
Dependent Claim
23 words
The measurement circuit of claim 6, wherein said processing circuit includes: a demodulator forming square wave pulses in response to flow of fluid.
Claim 10
Dependent Claim
21 words
The measurement circuit of claim 6, wherein: said demodulator includes a filter excluding signals at the operating frequency of electric light.
Claim 11
Dependent Claim
27 words
The measurement circuit of claim 6, wherein said processing circuit includes: a frequency/voltage converter forming an output signal having a voltage level indicative of fluid flow rate.
Claim 12
Dependent Claim
59 words
The measurement circuit of claim 6, wherein said processing circuit includes: an amplifier forming a group of pulses in response to flow of fluid; a demodulator forming square ware pulses in response to pulses from said amplifier; a frequency/voltage converter forming an output signal from the pulses from said demodulator having a voltage level indicative of fluid flow rate.
Claim 13
Dependent Claim
20 words
The measurement circuit of claim 11, said demodulator includes a filter excluding signals at the operating frequency of electric light.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-03-16 | 2001-09-15 | 2002-03-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-03-16 | 2005-09-15 | 2006-03-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-03-16 | 2009-09-15 | 2010-03-17 | $7700.00 | Window Closed / Lapsed |