US 5,627,323 A · Ultrasonic binary gas measuring device

Abstract

A method and apparatus to continuously measure the ratio of gasses in a binary gas mixture. A binary gas mixture is passed through a chamber in which a single ultrasonic wave travels from one piezoelectric transducer to another on the opposite side of the chamber. Immediately upon sensing an incoming ultrasonic wave, the transducer on opposite side of the chamber converts into a transmitter and transmits a single wave on top of the just received wave. The new wave travels back in the direction of the first transducer where it is received. The time of travel back and forth through the chamber is compared to a reference time, and represents the concentration of a gas in a binary gas mixture. The difference between time of travel in the direction of flow and against the direction of flow represents standard flow rate. A temperature sensor located in the middle of the chamber is used to temperature compensate the result. From the measured times, the temperature, the offset, and stored formulas a microprocessor calculates the gas concentration and/or the standard flow rate for the gas.

Claims25

Dependent claims

A method of measuring the ratio of gasses in a binary gas mixture comprising the steps of;

transmitting a first sound wave from an initial transmission point through the gas mixture,
detecting the arrival of said first sound wave at a receiving point a preselected distance from said initial transmission point,
then, after a given delay, transmitting an echo wave from said receiving point in the opposite direction, through the gas mixture, back to said initial transmission point,
said echo wave being of the same frequency and wave length as said first sound wave and superimposed thereon,
receiving said echo wave at said initial transmission point,
then measuring the travel time from the initial transmission to the time of reception of said echo wave to provide a measure of the relative proportions of the gases in said mixture, and
providing a display indicative of the relative proportions of said gasses.

4 more elements

In a sensor for determining the composition of a binary gas mixture, said sensor including a sealed gas chamber for containing said gas mixture, said chamber comprising a hollow conduit having end walls and an elongated cylindrical side wall, first and second acoustic transducers mounted a predetermined distance apart in said chamber and means for selectively energizing said transducers to transmit acoustic waves through said gas mixture, a gas ratio measurement system comprising in combination;

a first gas flow port in said side wall at one end of said conduit and a second gas flow port in said side wall at the other end thereof,
means for generating gas flow in a given direction within said conduit between said gas ports,
a switching network for alternately conditioning said transducers for transmitting and receiving said sound waves, and
a microprocessor apparatus connected to said switching network for conditioning said transducers such that one said transducers is energized to transmit a first sound wave of a given frequency and wave length to be received by the other transducer and then, immediately upon detection of said first sound wave, converting said other transducer to a transmitter and, within a given constant delay time, send a return echo sound wave of the same frequency and wave length to said one transducer superimposed on said first sound wave,
whereby the time from initial transmission of said first sound wave to the time of reception of said echo sound wave may be utilized to calculate the gas ratio measurement,
said microprocessor apparatus including means to measure the difference between the travel time of said first sound wave and said echo sound wave and to calculate the flow rate of said gas therefrom.

3 more elements

Dependencies are inferred from the claim text.

Ultrasonic binary gas measuring device

Life of this patent

Ultrasonic binary gas measuring device

Life of this patent

Abstract

Claims25