JPS588443B2 - Level detector using ultrasonic waves - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a level detector that electrically detects the inclination of a surface to be measured with respect to the horizontal using ultrasonic waves.

Conventionally, commonly used spirit levels measure the inclination of the surface to be measured with respect to the horizontal by visual inspection. In cases where measurement results are automatically displayed on a simple display device, it is necessary to detect the measurement results as electrical signals.

The present invention aims to provide a level detector that satisfies these requirements, and is intended to provide a level detector that uses two types of liquids with different specific gravity and sound speed, such that ultrasonic waves are refracted and propagated at the interface between them. Two liquids are filled in a container, and an ultrasonic transmitter is placed in one liquid at a central position in the container, and in the same horizontal plane at a symmetrical position or around the container in the other liquid. Install two or more ultrasonic receivers,
These ultrasonic receivers are characterized in that they are connected to a time difference detection circuit that detects the difference in time when ultrasonic waves are received by each receiver as the inclination of the container.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an outline of an apparatus for detecting a one-dimensional level based on the present invention.

In this level detector, two types of liquids having different specific gravity and sound speed are contained in a closed container 1 whose inner peripheral surface is made of an ultrasonic absorbing material, and ultrasonic waves are refracted and propagated through the interface between them. Two liquids 2,3 with almost the same acoustic impedance (product of specific gravity and sound speed), such as water (specific gravity 1.00, sound speed 1500 m/s) and chloroform (specific gravity 1.49, sound speed 1000 m/s) The ultrasonic transmitter 4 is placed at the center of one of the liquids 2, and
Ultrasonic wave receivers 5a and sb are attached to symmetrical positions on the inner wall of the container in the other liquid 3.

The ultrasonic receivers 5a and 5b are located in the same horizontal plane when the container 1 is placed on a horizontal plane, so both the ultrasonic receivers 5a and 5b are located in the same horizontal plane.
, 5b are located at the same distance from the transmitter 4.

The receivers 5a and sb are connected to a time difference detection circuit that detects the time difference between the outputs of the receivers.

In the level detector having the above configuration, when the ultrasonic wave is emitted as a pulse from the wave transmitter 4 in the liquid 2, a part of the ultrasonic wave propagates into the liquid 3 through the interface between the two liquids 2 and 3.
The waves are received by the respective receivers 5a and 5b,
In this case, if the container 1 is kept horizontally, the ultrasonic waves from the transmitter 4 are received by both receivers at the same time, as shown in FIG. If the time difference between the waveform outputs is detected, the time difference is O.

However, if the container 1 is tilted as shown in FIG. Since the propagation speed of the ultrasonic waves passing through them is different, both receivers 5a
, sb, there is a difference in the time at which the ultrasonic waves from the transmitter 4 are received, and by detecting the time difference in the time difference detection circuit, the inclination of the container 1, that is, the inclination of the surface to be measured, etc., is converted into an electrical signal. can be detected.

FIG. 3 shows an outline of a level detector that detects a two-dimensional level based on the present invention. There are two types of level detectors in a cylindrical container 11, which have different specific gravity and sound speed but have almost the same acoustic impedance. An ultrasonic transmitter 14 is provided at the center of one of the liquids 12, and a large number of ultrasonic receivers 15 are placed at equal intervals on the inner wall of the container in the other liquid 13. 15,... is installed.

The ultrasonic receivers 15, 15, . . . are located in the same horizontal plane when the container 11 is held horizontally,
These are connected to a time difference detection circuit (not shown).

In a two-dimensional level detector having such a configuration, when it is held horizontally, the ultrasonic waves from the transmitter 14 are simultaneously received by each receiver 15, 15, . . . However, if the container 11 is tilted with respect to the horizontal plane, the arrival time of the ultrasonic waves will be different at each receiver, and therefore the time difference detection circuit will detect the relative shift in the reception time at each receiver. By detecting this, it is possible to detect in which direction and to what degree the container is tilted with respect to the horizontal plane as an electrical signal.

As detailed above, according to the level detector of the present invention,
A one-dimensional or two-dimensional level can be detected as an electrical signal using an extremely simple device in which an ultrasonic transmitter and a receiver are installed in a container containing two types of liquids.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a level detector according to the present invention in a horizontal state, FIG. 2 is a sectional view of the level detector in an inclined state, and FIG. 3 is a perspective view of another embodiment of the present invention. 1,11...container, 2,3,12.13...liquid, 4,
14... Ultrasonic wave transmitter, 5a, 5b, 15... Ultrasonic wave receiver.

Claims (1)

[Claims] 1 A container is filled with two types of liquids that have different specific gravity and sound speed, and ultrasonic waves are refracted and propagated at the interface between them. A sonic wave transmitter is disposed, and two or more ultrasonic wave receivers are installed in the same horizontal plane at symmetrical positions or around the container in the other liquid, and these ultrasonic wave receivers are connected to each receiver. 1. A level detector using ultrasonic waves, characterized in that it is connected to a time difference detection circuit that detects the difference in time when ultrasonic waves are received in a wave detector as the tilt of a container.