Method and apparatus for testing liquid fillings in tanks

• US 5,036,703 A
• Filed: 02/21/1990
• Issued: 08/06/1991
• Est. Priority Date: 02/23/1989
• Status: Expired due to Fees

• Current Assignee: Bror A. Eriksson
• Original Assignee: Bror A. Eriksson
• Inventors: Eriksson, Bror A.
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Gutierrez, Diego F. F.
• Application Number:
  US07/482,935
• Time in Patent Office: 531 Days
• Field of Search: 73/290 V, 367/908, 374/117, 181/400, 181/402, 181/123, 181/124, 181/0.5
• US Class Current: 73/290.00V
• CPC Class Codes: G01F 23/2962 Measuring transit time of reflected waves
• CPC Class Codes: G01K 11/24 of the velocity of propagation of sound
• CPC Class Codes: G01N 2291/02836 Flow rate, liquid level
• CPC Class Codes: G01N 2291/02881 Temperature
• CPC Class Codes: G01N 29/024 by measuring propagation velocity or propagation time of acoustic waves
• CPC Class Codes: Y10S 181/402 Liquid
• CPC Class Codes: Y10S 367/908 Material level detection, e.g. liquid level

Abstract

The invention relates to a method and an apparatus for investigating a filling of liquid in a container, e.g. a fuel tank in respect of actual volume, density, temperature, opacity or other condition. From an emitter (19) at the bottom of the container there are emitted pulses of ultrasonic waves which are reflected by one or more horizontal border faces (17, 21) of the liquid and returned to the bottom of the container and detected by a receiver (20) there. The passage times of the reflected signals are compared with the passage times of direct and not-reflected signals that are detected by a plurality of receivers (1, 2, 3, 4, 5) placed above each other in fixed known positions. The result of said comparison is made the basis of a calculation of the sought quality. Measurement of the passage times, comparison, calculation and exposition of the result takes place by the use of electronic or data equipment (23).

Claims

1. A method for determining the level of an upper free surface of a liquid within a container and any horizontal border faces between adjacent layers of liquid in the container, the method comprising the steps of:

(a) emitting ultrasonic wave pulses from an emitter located in a bottom portion of the container upwardly through the liquid so that echoes of said wave pulses are reflected by said upper free surface and said horizontal border faces and returned for reception by a first receiver located proximate said emitter;

(b) measuring time between the emitting of said ultrasonic wave pulses from said emitter and reception of corresponding echoes by said first receiver;

(c) providing a plurality of additional receivers at predetermined levels above said bottom portion of the container such that at least some of said ultrasonic wave pulses are received directly within said plurality of additional receivers;

(d) measuring time between the emitting of said ultrasonic wave pulses from said emitter and direct reception by each of said plurality of additional receivers; and

(e) comparing the times measured in steps (b) and (d) and converting differences therebetween into one or more length measures indicative of levels of said upper free surface and said horizontal border faces within said container, and displaying said length measures.

2. The method according to claim 1 wherein the comparing step recited in step (e) is made after first having divided the time measured in step (b) by two.

3. The method according to claim 1 wherein the comparing step recited in step (e) is made after first having multiplied the time measured in step (d) by two.

4. Apparatus for determining the level of an upper free surface and any intermediate horizontal border faces of a liquid within a container comprising:

an emitter for intermittently emitting a plurality of ultrasonic wave pulses from a bottom portion of the container;

a first receiver located proximate said emitter for receiving ultrasonic wave pulses reflected by the upper free surface of the liquid and any horizontal border faces present within the liquid;

a plurality of second receivers placed at predetermined levels within said container above the bottom portion of the container for directly receiving wave pulses emitted by said emitter; and

, measuring and controlling means connected to the emitter and to said first and second receivers for measuring and making a comparison of passage times of reflected pulses received in said first receiver and pulses received directly by said plurality of second receivers and including means for displaying results of said comparison as a length measure indicating location of said upper free surface of said liquid and any horizontal border faces within said liquid.

5. Apparatus according to claim 4 wherein said second plurality of receivers comprises five receivers arranged in substantial vertical alignment within said container.

6. Apparatus according to claim 5 wherein one of said five receivers is located above said upper free surface of said liquid.

7. Apparatus according to claim 4 wherein said emitter and said first and second receivers are electrically connected to said measuring and controlling means by wires enclosed in a tube, and wherein said plurality of second receivers are mounted on said tube.

8. A method of examining liquid contents of a container by the utilization of ultrasonic waves, comprising the steps of:

(a) sending ultrasonic wave pulses through the liquid contents from an emitter in a bottom portion of the container such that said waves reflect from any horizontal border faces within the liquid contents as well as from an upper free surface of the liquid and are returned to a first receiver located proximate said emitter;

(b) measuring and recording passage times of said wave pulses reflected by said horizontal border faces and said upper free surface and returned to said first receiver;

(c) locating a plurality of additional receivers within said container at predetermined locations where said additional receivers directly receive at least some of said ultrasonic wave pulses emitted from said emitter;

(d) measuring and recording passage times of said ultrasonic wave pulses received directly by said additional receivers; and

(e) comparing the passage times recorded in steps (b) and (d) and displaying results of the comparison as length measures indicative of levels of said upper free surface and said horizontal border faces within the container.