Ultrasonic flow meter and method for ultrasonic flow metering

Patent metadata

Field	Value
Publication number	US-12339148-B2
Application number	US-202117905812-A
Country	US
Kind code	B2
Filing date	Mar 16, 2021
Priority date	Mar 20, 2020
Publication date	Jun 24, 2025
Grant date	Jun 24, 2025

Abstract

In an embodiment an ultrasonic flow meter includes a first transducer and a second transducer, a first impedance circuit and a second impedance circuit, each of the first and second impedance circuits having a variable impedance, a first terminal coupled to the first transducer via the first impedance circuit, a second terminal coupled to the second transducer via the second impedance circuit, a signal generator with a signal output and a signal evaluation circuit with a signal input, wherein the signal output and the signal input are coupled to the first and second terminals, and wherein the signal evaluation circuit includes a time-to-digital converter and a first comparator that couples the signal input to a first input of the time-to-digital converter, and a control circuit that is coupled to the signal generator, the signal evaluation circuit and the variable impedance.

First claim

The invention claimed is:

1. An ultrasonic flow meter comprising:
a first transducer and a second transducer;
a first impedance circuit and a second impedance circuit, each of the first and second impedance circuits comprising a variable impedance;
a first terminal coupled to the first transducer via the first impedance circuit;
a second terminal coupled to the second transducer via the second impedance circuit;
a signal generator with a signal output and a signal evaluation circuit with a signal input,
wherein the signal output and the signal input are coupled to the first and second terminals, and
wherein the signal evaluation circuit comprises a time-to-digital converter and a first comparator that couples the signal input to a first input of the time-to-digital converter; and
a control circuit coupled to the signal generator, the signal evaluation circuit and the variable impedance, the control circuit being configured to set the ultrasonic flow meter in an upstream mode and in a downstream mode and to set an impedance value of the variable impedance as a function of a first upstream time signal generated by the time-to-digital converter in the upstream mode and of a first downstream time signal generated by the time-to-digital converter in the downstream mode.

2. The ultrasonic flow meter according to claim 1 , wherein the variable impedance is configured to obtain one impedance value out of a number L of impedance values.

3. The ultrasonic flow meter according to claim 1 , wherein the control circuit is configured to optimize the impedance value of the variable impedance such that the first upstream time signal and the first downstream time signal differ by a time difference.

4. The ultrasonic flow meter according to claim 1 , wherein in the upstream mode, the first comparator is configured to generate a first comparator signal with a number K of pulses and the time-to-digital converter is configured to generate the first upstream time signal with the number K of values TOF_k_C1_l_UP corresponding to the number K of pulses of the first comparator signal, and
wherein in the downstream mode, the first comparator is configured to generate the first comparator signal with the number K of pulses and the time-to-digital converter is configured to generate the first downstream time signal with the number K of values TOF_k_C1_l_DOWN corresponding to the number K of pulses of the first comparator signal.

5. The ultrasonic flow meter according to claim 4 ,
wherein the control circuit is configured to determine a time difference and an lth impedance value out of a number L of possible impedance values at which the following sum f(l) obtains a minimum:

f
⁡
(
l
)

=

∑

k
=
1

K

(

TOF

k

C
⁢

1

l
UP

-

TOF

k

C
⁢

1

l
DOWN

-
DIFTOF

)

2

,

wherein TOF_k_C1_l_UP is a value of the first upstream time signal generated at a kth pulse of the number K of pulses of the first comparator signal using the lth impedance value of the number L of impedance values of the variable impedance in the upstream mode, and
wherein TOF_k_C1_l_DOWN is a value of the first downstream time signal generated at the kth pulse of the number K of pulses of the first comparator signal using the lth impedance value of the number L of impedance values of the variable impedance in the downstream mode.

6. The ultrasonic flow meter according to claim 1 , wherein the signal generator is configured to generate a square-wave signal having a number N of pulses.

7. The ultrasonic flow meter according to claim 1 , wherein the signal evaluation circuit comprises at least a second comparator that couples the signal input to at least a second input of the time-to-digital converter.

8. The ultrasonic flow meter according to claim 1 ,
wherein the signal evaluation circuit comprises a number M of comparators,
wherein the control circuit is configured to determine a time difference and a lth impedance value out of a number L of possible impedance values at which the following sum f(l) obtains a minimum:

f
⁡
(
l
)

=

∑

m
=
1

M

{

∑

k
=
1

K

(

TOF

k

C
⁢

m

l
UP

-

TOF

k

Assignees

• Sciosense Bv

Inventors

• Kern Stefan
• Coskunsu Faik

Classifications

• G01F1/667 Primary

  Arrangements of transducers for ultrasonic flowmeters; Circuits for operating ultrasonic flowmeters · CPC title