Ultrasound speed measurement of temperature and pressure effects

• US 6,571,643 B1
• Filed: 05/17/2000
• Issued: 06/03/2003
• Est. Priority Date: 08/13/1998
• Status: Expired due to Term

• Current Assignee: Pnf Co., Ltd.
• Original Assignee: Electronics For Imaging Incorporated
• Inventors: Plotkin, Serge, Wood, Robert P., Harel, Jacob, Hou, Alfred Samson
• Primary Examiner(s): MOLLER, RICHARD ALAN
• Application Number:
  US09/574,567
• Time in Patent Office: 1,112 Days
• Field of Search: 735/97, 738/611.8, 738/612.5, 738/612.7, 738/612.8, 738/612.9, 738/613.1
• US Class Current: 73/861.27
• CPC Class Codes: G01N 2291/02836 Flow rate, liquid level
• CPC Class Codes: G01P 13/02 Indicating direction only, e.g. by weather vane
• CPC Class Codes: G01P 5/245 by measuring transit time of acoustical waves measuring propagation velocity of acoustical waves per se G01H5/00
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/043 using propagating acoustic waves

Abstract

An apparatus and process for using ultrasound to measure speed and acceleration in fluids is provided. Three preferred embodiments are disclosed. The first preferred embodiment measures fluid velocity, such as, for example, wind, under standard atmospheric pressure-temperature. The second preferred embodiment measures gas velocity, such as, for example, wind, affected by and automatically calibrates for pressure-temperature. The third preferred embodiment measures gas density, such as, for example, density altitude. Applications of the invention include wind direction and speed calculation in agriculture, aviation, hydraulics, and other industries. One of the advantages provided by the invention is there are no moving parts in making such measurements.

Claims

1. A process for calculating a gas velocity vector in standard atmospheric pressure, the process comprising:

providing a first transmitter element adapted to transmit ultrasonic pulses, a second transmitter element adapted to transmit ultrasonic pulses and a receiver element adapted to receive ultrasonic pulses, whereby said first transmitter is positioned a first distance from said receiver, said second transmitter is positioned a second distance from said receiver and positioned at a 90 degree angle from and coplanar with said first transmitter;

transmitting a first ultrasonic pulse from said first transmitter to said receiver and calculating a first transit time for said first pulse to reach said receiver;

transmitting a second ultrasonic pulse from said second transmitter to said receiver and calculating a second transit time for said second pulse to reach said receiver;

calculating a first transit time differential vector by determining a first difference between said calculated first transit time and a first predetermined transit time of an ultrasonic pulse transmitted from said receiver to said first transmitter in standard atmospheric pressure;

calculating a second transit time differential vector by determining a second difference between said calculated second transit time and a second predetermined transit time of an ultrasonic pulse transmitted from said receiver to said second transmitter in standard atmospheric pressure; and

determining said gas velocity vector by combining said first transit time differential vector and said second transit time differential vector.

2. The process of claim 1, wherein said first transmitter, said second transmitter, and said receiver are adapted to be portable.

3. The process of claim 1, wherein said first transmitter comprises an ultrasonic piezoelectric transducer and said second transmitter comprises an ultrasonic piezoelectric transducer.

4. An apparatus for calculating a gas velocity vector in standard atmospheric pressure, the apparatus comprising:

a first transmitter element adapted to transmit ultrasonic pulses, a second transmitter element adapted to transmit ultrasonic pulses, a receiver element adapted to receive ultrasonic pulses, whereby said first transmitter is positioned a first distance from said receiver, said second transmitter is positioned a second distance from said receiver and positioned at a 90 degree angle from and coplanar with said first transmitter;

means for transmitting a first ultrasonic pulse from said first transmitter to said receiver and calculating a first transit time for said first pulse to reach said receiver;

means for transmitting a second ultrasonic pulse from said second transmitter to said receiver and calculating a second transit time for said second pulse to reach said receiver;

means for calculating a first transit time differential vector by determining a first difference between said calculated first transit time and a first predetermined transit time of an ultrasonic pulse transmitted from said receiver to said first transmitter in standard atmospheric pressure;

means for calculating a second transit time differential vector by determining a second difference between said calculated second transit time and a second predetermined transit time of an ultrasonic pulse transmitted from said receiver to said second transmitter in standard atmospheric pressure; and

means for determining said gas velocity vector by combining said first transit time differential vector and said second transit time differential vector.

5. The apparatus of claim 4, wherein said first transmitter, said second transmitter, and said receiver are adapted to be portable.

6. The apparatus of claim 4, wherein said first transmitter is an ultrasonic piezoelectric transducer and said second transmitter is an ultrasonic piezoelectric transducer.