Ultrasonic anemometer
First Claim
1. In a fluid flow measurement system including at least two spaced apart electroacoustic transducing means, a process for determining ultrasonic signal propagation times along a bidirectional signal propagation path between the transducing means, including the steps of:
- a. (i) causing a first one of the transducing means to generate a continuous wave acoustic signal in a first direction and receiving the continuous wave acoustic signal at the second transducing means;
(ii) causing the second transducing means to generate the continuous wave acoustic signal in a second direction opposite to the first direction, and receiving the continuous wave acoustic signal at the first transducing means;
(iii) causing the first transducing means to generate a single pulse acoustic signal in the first direction and receiving the single pulse acoustic signal at the second transducing means; and
(iv) causing the second transducing means to generate the single pulse acoustic signal in the second direction and receiving the single pulse acoustic signal at the first transducing means;
b. Determining respective signal propagation times TCW -1 and TCW -2 corresponding to propagation between the transmission means in the first and second directions based on respective phase comparisons of the sent and received continuous wave signal and determining a continuous wave time differential .increment.TCW based upon the difference in the respective propagation times;
c. Measuring respective single pulse propagation times TSP -1 and TSP -2 corresponding to propagation of the single pulse in the first and second directions, and determining a pulse time differential .increment.TSP based on the difference in the respective signal propagation times; and
d. Determining a value for the propagation time based upon a combination of the values .increment.TSP and .increment.TCW.
3 Assignments
0 Petitions
Accused Products
Abstract
An ultrasonic anemometer employs three ultrasonic transducers arranged in a configuration defining a horizontal equilateral triangle. Each of the transducers has a response profile characterized by a primary central lobe and secondary or side lobes angularly inclined from and surrounding the primary lobe. Each transducer is tilted from the horizontal to align the secondary lobes with signal propagation paths between it and the other transducers, thus affording a minimum number of transducers performing at a high degree of efficiency. Circuitry is employed to cause the ultrasonic transducers to generate either continuous wave acoustic signals or single pulse acoustic signals on an alternating basis. In each case only one of the transducers transmits the acoustic signal while the other two transducers receive the signal. Propagation measurements based upon the continuous wave and the single pulse are combined to provide a composite propagation time, for each of two opposite directions in connection with each propagation path. These values in turn are combined to obtain a single vector representation of wind speed and direction.
90 Citations
18 Claims
-
1. In a fluid flow measurement system including at least two spaced apart electroacoustic transducing means, a process for determining ultrasonic signal propagation times along a bidirectional signal propagation path between the transducing means, including the steps of:
-
a. (i) causing a first one of the transducing means to generate a continuous wave acoustic signal in a first direction and receiving the continuous wave acoustic signal at the second transducing means;
(ii) causing the second transducing means to generate the continuous wave acoustic signal in a second direction opposite to the first direction, and receiving the continuous wave acoustic signal at the first transducing means;
(iii) causing the first transducing means to generate a single pulse acoustic signal in the first direction and receiving the single pulse acoustic signal at the second transducing means; and
(iv) causing the second transducing means to generate the single pulse acoustic signal in the second direction and receiving the single pulse acoustic signal at the first transducing means;b. Determining respective signal propagation times TCW -1 and TCW -2 corresponding to propagation between the transmission means in the first and second directions based on respective phase comparisons of the sent and received continuous wave signal and determining a continuous wave time differential .increment.TCW based upon the difference in the respective propagation times; c. Measuring respective single pulse propagation times TSP -1 and TSP -2 corresponding to propagation of the single pulse in the first and second directions, and determining a pulse time differential .increment.TSP based on the difference in the respective signal propagation times; and d. Determining a value for the propagation time based upon a combination of the values .increment.TSP and .increment.TCW. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A signal processing apparatus for a fluid velocity measuring system, including:
-
a plurality of electroacoustic transducing means mounted in spaced apart relation to one another within a fluid flow, said transducing means cooperating to define a set of linear bidirectional acoustic signal propagation paths comprised of one of said propagation paths between each pair of the transducing means; a first signal generating means for generating a first electrical signal in the form a continuous wave; a second signal generating means for generating a second electrical signal in the form of a an individual pulse; a coupling means for selectively electrically coupling the first signal generating means and the second signal generating means with the transducing means to cause the transducing means to generate a continuous wave acoustic signal in response to receiving the first electrical signal and, alternatively, to generate an acoustic pulse in response to receiving the second electrical signal;
wherein each the transducing means, in response to receiving the acoustic continuous wave signal and the acoustic pulse, respectively generates a third electrical signal in the form of a continuous wave and a fourth electrical signal in the form of an individual pulse;a detecting means coupled to the transducing means and to the first and second pulse generating means, for sensing the first, second, third and fourth electrical signals; a counting means coupled to the detecting means for generating a plurality of values with respect to each of the propagation paths, including first and second values representing acoustic signal propagation times along the associated path in first and second opposite directions, and third and fourth values representing propagation time of the pulse in the first and second directions; and a computing means coupled to the counting means for calculating, with respect to each propagation path, a composite signal propagation time in said first direction based upon the first and third values, and a composite signal propagation time in the second direction based upon said second and fourth values. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14)
-
-
15. In a fluid flow measurement system including at least three spaced apart electroacoustic transducers defining a plurality of linear, co-planar and bidirectional acoustic signal propagation paths in at least three non-parallel directions between adjacent pairs of the transducers, a process for measuring fluid flow velocity and direction in the plane of the signal propagation paths, including the steps of:
-
causing each one of the transducers to generate acoustic signals and alternatively to receive acoustic signals generated by at least one of the other transducers; determining respective signal propagation times corresponding to propagation of the acoustic signals in first and second opposite directions along each of the propagation paths; computing a fluid velocity value V along each of the signal propagation paths, each value V being a vector in the direction of its associated signal propagation path and computed based on the signal propagation times in the first and second directions along the associated path; determining whether any of the vectors V is at least substantially aligned with the direction of fluid flow, to identify each of the vectors V as either so aligned or non-aligned; and combining only the non-aligned vectors V to provide a single resultant vector representing fluid flow velocity and direction. - View Dependent Claims (16, 17, 18)
-
Specification