Speed and fluid flow controller

Details Speed and fluid flow controller Speed and fluid flow controller

2006-01-03

2006-01-03

Williams, Hezron (Department: 2856)

Measuring and testing

Gas analysis

Impurity

C073S023200, C388S823000, C388S815000

Reexamination Certificate

active

06981402

ABSTRACT:
A system and method for measuring fluid flow rate in a system where fluid is pumped, such as a gas monitoring instrument where gas is pumped from a space such as a room or enclosure through a conduit to a sensor. The flow of gas through a pump is determined by measuring motor back-e.m.f. which is proportional to motor speed. In a system where motor speed is regulated by pulse width modulation of the motor drive voltage, the back-e.m.f. is sampled during intervals between the drive pulses applied to the motor, and in a further aspect the sampling is done at selected, spaced-apart or infrequent intervals such as once for every ten or once for every hundred motor drive pulses. Advantageously, in an instrument that uses a microprocessor and analog-to-digital converter to measure gas-concentration, the same microprocessor and converter can provide the PWM control of the pump, in response to the back-e.m.f. generated by the pump motor between the drive pulses. The microprocessor compares the output of the analog-to-digital converter, corresponding to the back-e.m.f., which in turn corresponds to the pump motor speed, to a set-point value, representative of the desired pump motor speed. The processor then adjusts the PWM to control the pump motor to achieve and maintain the desired speed. As a result, in a gas monitor, the gas-flow rate may be maintained close to a desired gas flow rate regardless of the voltage supplied by the battery or other voltage source, regardless of the degree to which the gas is filtered, and under a wide range of operating conditions.

REFERENCES:
patent: 3588654 (1971-06-01), Balazs
patent: 3683253 (1972-08-01), Rummel et al.
patent: 3803470 (1974-04-01), Vesteen
patent: 3873814 (1975-03-01), Mirdadian
patent: 3950989 (1976-04-01), Meirowitz
patent: 4241299 (1980-12-01), Bertone
patent: 4292574 (1981-09-01), Sipin et al.
patent: 4384825 (1983-05-01), Thomas et al.
patent: 4527953 (1985-07-01), Baker et al.
patent: 4638233 (1987-01-01), Erdman
patent: 4884013 (1989-11-01), Jackson et al.
patent: 4893067 (1990-01-01), Bhagwat et al.
patent: 5048115 (1991-09-01), Venturino
patent: 5107713 (1992-04-01), Peck et al.
patent: 5601413 (1997-02-01), Langley et al.
patent: 5714862 (1998-02-01), Mikesell et al.
patent: 5933795 (1999-08-01), Schottler et al.
patent: 6247980 (2001-06-01), Moore et al.
patent: 6363802 (2002-04-01), Grippo et al.
patent: 6402478 (2002-06-01), Zhang et al.
patent: 000071848 (1983-02-01), None
patent: 363223446 (1988-09-01), None

Affiliated with

Also associated with

Rating

Speed and fluid flow controller does not yet have a rating. At this time, there are no reviews or comments for this patent.

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

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3587675