1D ULTRASONIC TRANSDUCER UNIT FOR MATERIAL DETECTION

Abstract

A 1D ultrasonic transducer unit for material detection, comprising a housing having securing device for securing to a surface and having at least three discrete ultrasonic transducers designed to decouple sound waves with a consistent operating frequency between 20 kHz and 400 kHz in a gaseous medium, and a control unit designed to control each ultrasonic transducer individually, wherein two ultrasonic transducers, directly adjacent to one another, are spaced apart by a distance, the 1D ultrasonic transducer unit has a sound channel per ultrasonic transducer with an input opening, associated with exactly one respective ultrasonic transducer, and an output opening, the output openings are arranged along a straight line, a distance from the directly adjacent output opening corresponds at most to the full or half the wavelength in the gaseous medium and is smaller than the corresponding distance.

Claims

1. A 1D ultrasonic transducer unit for material detection, the transducer unit comprising: a housing; at least three ultrasonic transducers; and a control unit adapted to control each ultrasonic transducer individually, wherein the housing has a communication interface, wherein each ultrasonic transducer has a transducer housing, a piezoelectric body disposed in the transducer housing, and a sound decoupling layer disposed at an open end of the transducer housing for decoupling sound waves in a gaseous medium, and is disposed at a fixed position in the housing, wherein each ultrasonic transducer is designed to emit and/or to receive a sound wave with a consistent working frequency, wherein the working frequency of the sound waves is in a range from 20 kHz to 400 kHz, wherein, two ultrasonic transducers, directly adjacent to one another, in the housing are spaced apart by a distance from a center of the sound decoupling layer to a center of the sound decoupling layer of at most 10 cm or at most 5 cm or at most 2 cm, wherein the 1D ultrasonic transducer unit has one sound channel per ultrasonic transducer, wherein each sound channel has an input opening and an output opening, wherein exactly one of the input openings is associated with each sound decoupling layer, wherein the output openings are arranged along a straight line, wherein the output openings are each arranged in a wall of the housing, or the sound channels penetrate the wall of the housing, wherein a distance from a center of one of the output openings to a center of a directly adjacent output opening corresponds at most to the wavelength in the gaseous medium or at most to half the wavelength in the gaseous medium, wherein a distance between two directly adjacent output openings is in each case smaller than a distance between the ultrasonic transducers associated with the corresponding input openings, wherein a quotient of a surface area of the output opening to a surface area of the input opening has a value between 0.30 and 1.2, wherein each sound channel has at least a length corresponding to the diameter of the input opening, wherein the housing has a securing device for securing to a surface, wherein the control unit is at least partially disposed in the housing, wherein the housing has a movable cover device designed to close the output openings of all sound channels, and wherein the output openings of all sound channels lie in a curved surface.

2. The 1D ultrasonic transducer unit according to claim 1, wherein the quotient of the surface area of the output opening to the surface area of the input opening has a value between 0.5 and 1.5 or between 0.9 and 1.1.

3. The 1D ultrasonic transducer unit according to claim 1, wherein each sound channel has a length from the sound decoupling layer of each ultrasonic transducer to the output opening of the associated sound channel and the length is an integral multiple of one eighth of the wavelength of the sound frequency or an integral multiple of half the wavelength of the sound frequency.

4. The 1D ultrasonic transducer unit according to claim 1, wherein each sound channel is formed of a metal or a plastic or comprises a metal or a plastic.

5. The 1D ultrasonic transducer unit according to claim 1, wherein each ultrasonic transducer has a sound uncoupling layer between the sound decoupling layer and the transducer housing.

6. The 1D ultrasonic transducer unit according to claim 1, wherein the control unit is disposed completely or partially in the housing.

7. The 1D ultrasonic transducer unit according to claim 1, wherein the housing of the 1D ultrasonic transducer unit is designed at least according to the IP 40 protection class.

8. The 1D ultrasonic transducer unit according to claim 1, wherein the communication interface is designed for wireless data transmission.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

[0045] FIG. 1A is a view of a first embodiment of the invention of a 1D ultrasonic transducer unit for level detection;

[0046] FIG. 1B is a view of a second embodiment of the invention of a 1D ultrasonic transducer unit for object detection;

[0047] FIG. 2 is a sectional view of an embodiment of the invention of a housing of a 1D ultrasonic transducer unit;

[0048] FIG. 3 shows a view of a further embodiment of the invention of the sound channels;

[0049] FIG. 4 is a view of a further embodiment of the invention of the sound channels;

[0050] FIG. 5 shows a view of a further embodiment of an individual sound channel; and

[0051] FIG. 6 shows a view of various embodiments of an output surface of a sound channel.

DETAILED DESCRIPTION

[0052] The illustration in FIG. 1A shows a view of a first embodiment of a 1D ultrasonic transducer unit 10 of the invention for level detection. The 1D ultrasonic transducer unit has a housing 14 which is attached with a securing device 11 to a cover 102 of a container 102 for a bulk material 104. Sound waves 11 are generated by 1D ultrasonic transducer unit 10. Sound waves 11 have a main direction of propagation, wherein the main direction of propagation in the image plane can be pivoted (dashed line, dotted line, or dot-dashed line), as a result of which the entire container 102 can be reliably scanned. Bulk material 104 and/or a bottom of container 102 and/or a side wall of container 102 reflect sound waves 11. By means of the 1D ultrasonic transducer unit, both the height or quantity of bulk material 104 and a surface structure of bulk material 104 can be detected, as a result of which conclusions about the type of bulk material 104 are possible.

[0053] A second embodiment of the invention of 1D ultrasonic transducer unit 10 is shown in the illustration of FIG. 1B. 1D ultrasonic transducer unit 10 is attached with securing device 11 to a building ceiling 106 above a conveyor belt 108, so that objects 110 on the conveyor belt can be detected by means of the ultrasonic waves. By pivoting the emitted ultrasonic waves, it is possible to monitor a rather large area of conveyor belt 108 and to recognize the shape or the surface structure of objects 110 located on conveyor belt 108.

[0054] A sectional view of a housing 14 of an ultrasonic transducer unit 10 is shown in the illustration of FIG. 2. In housing 14, five discrete ultrasonic transducers 12 are arranged along a planar rear wall 16 of housing 14. Each ultrasonic transducer 12 has its own transducer housing 18 and a sound decoupling layer 20. Each ultrasonic transducer 12 is spaced apart by a distance A1 from the directly adjacent ultrasonic transducer(s) 12 from the center of sound decoupling layer 20 to the center of sound decoupling layer 20.

[0055] A sound channel 22 is associated with each ultrasonic transducer 12, wherein each sound channel 22 has an input opening 24 and an output opening 26. Input openings 24 are each arranged in front of or around one of ultrasonic transducers 12, so that the respective ultrasonic transducer 12 emits into sound channel 22. Output openings 26 of sound channels 22 are arranged along a planar front wall 30 of housing 14, said front wall being opposite the rear wall, or penetrate front wall 30.

[0056] In each case two adjacent output openings 26 are spaced apart by a distance A2 from the center of output opening 26 to the center of output opening 26. According to the invention, the distance A2 between output openings 26 is in each case less than or equal to the distance A1 of the assigned or associated ultrasonic transducer 12.

[0057] A length L1 from each sound decoupling layer 20 to output opening 26 of the associated sound channel 22 is an integral multiple of one eighth of the wavelength of the sound frequency.

[0058] Housing 14 also comprises a movable cover device 32. Cover device 32 is in a closed state in the illustrated exemplary embodiment. For this purpose, the cover device is arranged in front of front wall 30 of housing 14 with output openings 26, so that sound channels 22 are closed. In an open state, cover device 32 is no longer located in front of front housing wall 30 and output openings 26, for example, by folding or sliding, and output openings 26 are uncovered.

[0059] In the exemplary embodiment shown in FIG. 3, sound channels 22 run so that output openings 26 of all sound channels 22 lie in a common flat plane E1. In the illustrated embodiment, front wall 30 of housing 14 of 1D ultrasonic transducer unit 10 runs within plane E1. A region 34 of the respective sound channel 22, said region still located in front of input opening 24 of each sound channel 22, is designed so that the respectively associated ultrasonic transducer 12 fits precisely into sound channel 22. For this purpose, each sound channel 22 in the region has an inner diameter corresponding to outer diameter D1 and an edge 36 serving as a stop.

[0060] A control unit (not shown) is designed to control each ultrasonic transducer 12 individually. By controlling the individual ultrasonic transducers 12 in a time-shifted or phase-shifted manner, 1D ultrasonic transducer unit 10 generates planar ultrasonic waves with a main direction of propagation (arrows), wherein the main direction of propagation or an angle between the main direction of propagation and the first plane E1 can be set by means of the phase offset between the sound waves emerging from output openings 26 of the individual sound channels.

[0061] In the exemplary embodiment shown in FIG. 4, output openings 40 of all sound channels 36 lie in a concavely curved surface F1.

[0062] An individual sound channel 22 is shown schematically in the illustration in FIG. 5, only the differences from FIGS. 1 to 4 being explained below.

[0063] Input opening 24 has a cross-sectional area with a width x1 and a height y1, and output opening 26 has a cross-sectional area with a width x2 and a height y2.

[0064] Input opening 24 is formed circular; i.e., the width x1 and height y1 of the cross-sectional area have the same value. Output opening 26, in contrast, has an oval shape, so that the width x2 of the cross-sectional area is smaller than the width y2.

[0065] The width x2 of output opening 26 is preferably smaller than the width x1 of input opening 24. In contrast, the height y2 of output opening 26 is preferably greater than the height y1 of input opening 24. The increase in the height of sound channel 22 particularly preferably compensates for the decrease in the width of sound channel 22, so that the surface area of the cross-sectional area of input opening 24 corresponds to the surface area of the cross-sectional area of output opening 26.

[0066] It is understood that the width x2 of each output opening 26 must be smaller than the wavelength of the sound frequency in order to be able to realize a distance from the center of output openings 26 to the center of a directly adjacent output opening 26 of at most the wavelength of the sound frequency.

[0067] In the illustration in FIG. 6, a number of exemplary embodiments of the invention of the cross-sectional areas of output openings 26 are shown schematically. So that the surface area of the cross-sectional area of output opening 26 corresponds to the surface area of the cross-sectional area of input opening 24, shapes are particularly suitable that have a ratio of width x2 to height y2 of approximately 1.5

[0068] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.