JPS61207927A - Stable measuring method for ultrasonic level instrument - Google Patents

Abstract

PURPOSE:To execute exactly a measurement without being influenced by whether a noise exists or not, by detecting a noise in a measuring gate, whenever an acoustic wave is emitted, deriving an average value, adding it to a discriminating value of the time of no-noise, setting it as a discriminating value, and executing the measurement. CONSTITUTION:Whenever an acoustic wave is emitted, a noise in a measuring gate is detected and an average value is derived, it is added to a discriminating value of the time of no-noise, it is set as a discriminating value, and a measurement is executed. In this way, when measuring a charging quantity of an object for generating a noise when it is charged such as an ore, etc., by an ultrasonic level instrument, no erroneous measurement is executed by its noise, and also the measurement can be executed even in case it is not charged.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to measuring the filling amount of various measurement objects using an ultrasonic level meter, for example, when an object such as ore that generates noise when put into a container. The present invention relates to a method for stably measuring the filling amount of water using an ultrasonic level meter without erroneously detecting it.

[Prior art] This type of ultrasonic level meter A measures the filling amount of lumpy solids, granules, and powders put into a container, and uses an ultrasonic oscillator as shown in Fig. 4. By emitting a sound wave from (a) and measuring the time ll1t until it bounces off the surface of the content α, the distance is determined from the following formula and this is displayed as the filling amount of the content.

To explain this measurement in more detail, as shown in Figure 5, it is measured by detecting a reflected wave (b) that appears after 11 seconds and exceeds the identification value (threshold level) 1, which is set to a predetermined value. is being carried out. That is 11
What appears before the second is the launch reverberation (c), so it is not measured even if it is detected, and even after 11 seconds, the reflected wave (b) that does not exceed the discrimination value ■1 is the ultrasonic oscillator ( b) It is not measured because it did not bounce off the surface of the content α directly below, but the measurement is performed by sensing the reflected wave (b) that exceeds the identification value ■1 after t1 seconds, and the result is If the reflected wave (b) is detected at the time of t1 seconds, the filling amount is displayed as 100%, and at the time of seconds, it is displayed as 0%.

However, when using this ultrasonic level meter A to measure the filling amount of something that generates noise when loading, such as ore, the ultrasonic component in the collision sound generated when ore is loaded exceeds the identification value ■1, This results in false detection and unstable filling amount measurement.

In other words, to explain the reflected wave (b) at this time, the reflected wave (b) appears in the form of being added to the noise (d) as shown in Fig. 6, but the reflected wave ( Since the noise (d) exceeds the identification value v1 at t2 seconds before b), this is detected and a value different from the actual filling amount is shown. In this case, if you raise the level of identification value ■1 in advance as shown by the dotted line, you can set the reflected wave (
(b) only exceeds the discrimination value V1', but in that case, when there is no noise (d) such as when the power is not turned on, the discrimination value V
The level of 1' is too high and the reflected wave (mouth') does not exceed this level, making it impossible to measure.

[Problems to be Solved by the Invention] However, the present invention aims to prevent erroneous measurements caused by the noise when measuring the filling amount of an object such as ore with an ultrasonic level meter, which generates noise when being charged, and to ensure that no erroneous measurements are made due to the noise. The purpose of the present invention is to provide a stable measurement method using an ultrasonic level meter that enables measurement even at times.

[Means for solving problems] The method of the present invention will be explained based on FIG.

In the method of the present invention, the reflected wave (b) appears as a result of being added to the noise (d), and can be distinguished from the level of the noise (d).

The average value VO is obtained by detecting the noise (d) in the noise, and adding it to the identification value 11V1 when there is no noise, and setting this as the identification value ■ for measurement.

Note that noise (d) is not limited to the sound generated when loading ore, etc., but regardless of the type of object to be measured, and may include noise generated during transport, noise that may enter during measurement depending on the installation location of ultrasonic level meter A, In other words, it does not matter whether the noise is internal or external.

[Function] Since the present invention is constructed as described above, for example, when looking at the case where the noise (d) is large as shown in FIG. Identification value v1
Since the discrimination value (■) is set to the value obtained by adding the above, the level of the discrimination value V is high, and only the reflected wave (b) exceeds the discrimination value (■). Also, if we look at the case where the noise (d) is of medium or low intensity as shown in Figure 2, in this case as well, the value obtained by adding the discrimination value v1 when there is no noise to the average value vO' of the noise (d) is Since it is set as the identification value v', only the reflected wave (b) exceeds this identification value V'. Furthermore, as shown in Figure 3, when there is no noise, the average value of noise (d) is 0, and the value obtained by adding the identification value ■1 when there is no noise, that is, Discrimination value (2) when there is no noise Since the value as it is is set as the discrimination value VH, the reflected wave (b) naturally exceeds the discrimination value VII.

[Effects] As described above, according to the method of the present invention, even when there is noise such as when ore is added, accurate measurement is possible because only the reflected wave exceeds the identification value. Even if there is no noise, the reflected wave will exceed the identification value, making measurement possible. That is, the method of the present invention has an extremely excellent effect of being able to perform accurate measurements without being affected by the presence or absence of noise.

[Brief explanation of the drawing]

Figures 1 to 3 are diagrams explaining the measurement method of the present invention, Figure 4 is a diagram explaining the measurement principle of an ultrasonic level meter, Figure 5 is a diagram explaining the conventional measurement of an ultrasonic level meter, and Figure 6 is a diagram explaining the measurement principle of the ultrasonic level meter. FIG. 2 is an explanatory diagram of problems caused by conventional fixed identification value setting. A... Ultrasonic level meter vo, vo'... Average value of noise ■1... Discrimination value when there is no noise v, v', v''... Discrimination value to... Measurement gate i...・Ultrasonic oscillator Mouth: Reflected wave C: Emission reverberation 2: Noise Figure 1 Figure 2 Figure 8 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1. Ultrasonic level measured by detecting noise in the measurement gate each time a sound wave is emitted, finding the average value, adding it to the discrimination value when there is no noise, and setting this as the discrimination value. Stable measuring method for an ultrasonic level meter 2: The noise is generated when the object to be measured is introduced into the instrument (claim 1) Stable measuring method for an ultrasonic level meter 3: The object to be measured is an ore Stable measurement method of the ultrasonic level meter described in paragraph 1 or 2