JP2023078535A - Liquid type specification device and liquid container - Google Patents

Abstract

To provide a liquid type specification device and a liquid container with improved merchantability.SOLUTION: A liquid type specification device includes: a propagation body 10 arranged at a position opposite to a bottom 3a of a container 3 and having a propagation surface 11 on which a surface wave Ws propagates; a piezoelectric element 30 that generates the surface wave Ws by imparting vibration to the propagation body 10 to detect a reflected surface wave Ws; and a control unit 2 for specifying a type of a liquid 4 based on a propagation time of the surface wave Ws detected by the piezoelectric element 30. The propagation surface 11 is a non-flat surface toward a liquid level 4a side of the liquid 4 as it is separated from the piezoelectric element 30.SELECTED DRAWING: Figure 2

Description

The present invention relates to a liquid type identification device and a liquid container.

Conventionally, for this type of liquid type identification device, for example, one described in Patent Document 1 below is known. The liquid type identification device described in Patent Document 1 includes a propagating body that is immersed in a liquid and has a propagation surface on which surface waves propagate, and a surface wave that is generated by vibrating the propagating body and reflected by a surface wave reflecting portion. It comprises a piezoelectric element for detecting surface waves, and a fuel tank (storage member) that houses liquid and a propagating body. can be attached to Then, the type of liquid is specified based on the surface wave propagation period, which is the period from when the vibration is applied to the propagating body until the surface wave is reflected by the surface wave reflecting portion and is input to the piezoelectric element. .

JP 2018-54321 A

By the way, when the propagating body is installed in the fuel tank of a ship that travels on the sea, it is conceivable that seawater will enter the fuel tank in which gasoline is stored under stormy weather. When seawater enters the fuel tank, the seawater settles to the bottom of the fuel tank because the specific gravity of seawater is greater than that of gasoline.

At this time, under the condition that seawater is mixed up to the propagation surface, it is possible to identify that the seawater is mixed in the container based on the surface wave propagation period, but the propagation surface is parallel to the bottom of the fuel tank. Moreover, because the propagating body is attached to the fuel tank so as to face the bottom side, highly viscous gasoline adheres to the propagating surface and becomes difficult to separate from the propagating surface. As a result, it becomes difficult to identify that seawater has entered the fuel tank, which causes a problem of deterioration of marketability.

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid type identifying device and a liquid container with improved marketability in order to address the above-described problems.

In order to achieve the above object, the present invention provides a liquid type identification device that is attached to a storage member that stores a liquid and that determines the type of the liquid. a propagating body having a propagating surface along which a surface wave propagates; a piezoelectric element for generating the surface wave by vibrating the propagating body and detecting the reflected surface wave; and the surface wave detected by the piezoelectric element. and a specifying unit that specifies the type of the liquid based on the propagation time of the liquid, wherein the propagation surface is a non-flat surface that moves toward the liquid surface side of the liquid as the distance from the piezoelectric element increases. do.

ADVANTAGE OF THE INVENTION According to this invention, the liquid type identification apparatus and liquid container which can achieve the intended objective and improved marketability can be provided.

1 is a schematic configuration diagram of a liquid type identification device according to an embodiment of the present invention; FIG. The figure which expanded the principal part of the liquid type identification apparatus in FIG. FIG. 4 is a schematic cross-sectional view of a propagating body, an element accommodating portion, and a piezoelectric element according to the same embodiment; FIG. 4 is a plan view of a propagating body and an element housing portion when viewed from the bottom side of the housing member according to the same embodiment; AA sectional view of FIG. 4 (hatching is omitted). FIG. 4 is a schematic diagram showing waves input to the piezoelectric element when vibration is applied to the propagating body; FIG. 5 is a schematic cross-sectional view of a propagating body, an element accommodating portion, and a piezoelectric element according to a modification of the same embodiment; FIG. 10 is a schematic cross-sectional view of a propagating body, an element accommodating portion, and a piezoelectric element according to another modified example of the same embodiment;

An embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, 1 is a surface wave detector, 2 is a controller, 3 is a container as a storage member, 4 is a liquid contained in the container 3, and 4a is the liquid surface of the liquid 4. These surface wave detectors are shown in FIG. 1 and the control unit 2 constitute a liquid type identification device L for identifying the type of liquid 4 (hereinafter also referred to as liquid type) contained in the container 3 . Note that the container 3 (to which the liquid type identification device L is attached) here is a fuel tank mounted on a moving object such as a ship traveling on the sea.

The surface wave detection device 1 includes a propagating body 10 immersed in a liquid 4, an element accommodating portion 20, a piezoelectric element 30, and a flange portion 40, as shown in FIGS.

Hereinafter, as shown in each figure, the X-axis extending in the longitudinal direction of the propagating body 10, the Z-axis extending in the normal direction of the facing surface 12 described later, and the Y-axis orthogonal to the X-axis and the Z-axis are used. , the configuration of the surface wave detection device 1 may be described. Also, the directions along the X, Y, and Z axes are defined as the axial directions. Further, the direction in which the arrows of the X, Y, and Z axes point is the "+" direction, and the opposite direction is the "-" direction. That is, the direction along the X axis is the X direction. Considering the directions of the arrows, the direction in which the X-axis arrow points is the +X direction, and the opposite direction is the -X direction. The same applies to the Y and Z axes.

The propagating body 10 propagates an ultrasonic wave including a surface wave Ws, which will be described later, and is made of a synthetic resin such as PPS (polyphenylene sulfide). The propagating body 10 is arranged at a position facing the bottom of the container 3, which will be described later.

The propagating body 10 extends in the X-axis direction and has a generally rectangular prism shape. As shown in FIG. 5, the propagating body 10 has a substantially H-shaped cross section, and includes a substantially quadrangular prism-shaped base portion 10a constituting the main portion thereof. A central portion of the base portion 10a is provided with a propagation surface 11 and a facing surface 12 facing the propagation surface 11 at positions facing each other in the Z direction in FIG. Further, in FIG. 5, a first rib R1 and a second rib R2 are provided on the upper left and lower left portions of the base portion 10a so as to protrude from the outer surface of the base portion 10a. The portion is provided with a third rib R3 and a fourth rib R4 so as to protrude from the outer surface of the base portion 10a. Thus, in this example, the propagating body 10 includes the propagating surface 11, the opposing surface 12, the side surfaces 13 and 14, the first rib R1, the second rib R2, the third rib R3, and the fourth rib R4. and have Further, the propagating body 10 has a bottom surface 15 shown in FIGS.

The propagation surface 11 is a portion of the propagation body 10 through which the surface wave Ws propagates, and is provided at a position facing (opposing) the bottom of the container 3, which will be described later, as shown in FIG. The propagation surface 11 here is non-parallel to the flat bottom portion as shown in FIGS. , and is provided in a strip shape in the X direction as shown in FIG. The −X-direction end of the propagation surface 11 functions as a reflecting portion 11a that reflects the surface wave Ws.

The facing surface 12 is provided at a position facing the propagation surface 11 with the base portion 10a interposed therebetween, as shown in FIGS. The facing surface 12 is also provided in a belt-like shape extending in the X direction. The propagation surface 11 faces the -Z direction, and the opposing surface 12 faces the +Z direction. The opposing surface 12 is parallel to the XY plane, and the propagation surface 11 is not parallel to the XY plane, but is an inclined surface directed in the +Z direction as the distance from the piezoelectric element 30 increases, as described above. That is, in this example, as shown in FIG. 3, the thickness of the base 10a along the Z direction (that is, the direction perpendicular to the facing surface 12) gradually decreases with increasing distance from the piezoelectric element 30. As shown in FIG.

Further, as shown in FIGS. 2 and 3, a groove 12a recessed from the facing surface 12 toward the propagation surface 11 is formed in the propagation body 10 (base portion 10a). Note that FIG. 2 shows a side view of the propagating body 10 and the element accommodating portion 20 as seen from the -Y direction. 3 is a cross-sectional view of the propagating body 10, the element accommodating portion 20, and the piezoelectric element 30 taken along a plane parallel to the XZ plane.

As shown in FIG. 5, the side surface 13 faces the -Y direction and the side surface 14 faces the +Y direction. Sides 13 and 14 are parallel to the XZ plane. The bottom surface 15 is an inclined surface that connects the propagation surface 11 and the opposing surface 12, as shown in FIGS. The bottom surface 15 forms an acute angle with the propagation surface 11 and forms an obtuse angle with the opposing surface 12 . The bottom surface 15 forms a tapered shape at the tip of the propagating body 10 . Due to the inclination of the bottom surface 15, the surface wave Ws propagating in the −X direction on the propagation surface 11 can be suppressed from going around to the opposing surface 12, reflected by the reflecting portion 11a of the propagation body 10, and propagated on the propagation surface 11 again. Therefore, the surface wave Ws can be directed toward the piezoelectric element 30 efficiently.

As shown in FIG. 5, the first rib R1 and the second rib R2 protrude in the direction in which the propagation surface 11 faces (that is, the −Z direction from the base 10a), and correspond to the propagation surface 11 as shown in FIG. It is provided in a belt shape in the X direction so as to do so. The first rib R1 and the second rib R2 face each other across the propagation surface 11 in the width direction (Y direction) of the propagation surface 11, as shown in FIG. Also, the heights (heights in the Z direction) of the first ribs R1 and the second ribs R2 from the propagation surface 11 are preferably equal and set equal to or greater than the wavelength λ of the surface wave Ws.

A curved surface portion S1 connected to the propagation surface 11 is formed at the base end portion of the first rib R1. Specifically, the curved surface portion S1 connects the propagation surface 11 with the first opposing surface portion So1, which is the inner surface of the first rib R1 (the surface facing the −Y direction) and faces the second rib R2. A curved surface portion S2 connected to the propagation surface 11 is formed at the base end portion of the second rib R2. Specifically, the curved surface portion S2 connects the propagation surface 11 with the second opposing surface portion So2 that is the inner surface (the surface facing the +Y direction) of the second rib R2 and faces the first rib R1. Here, actually, the surface wave Ws due to vibration of the piezoelectric element 30 is generated not only on the propagation surface 11 but also around the propagation surface 11 . By providing the curved surface portions S1 and S2 as described above, the surface waves Ws generated in the propagating body 10 can be collected on the propagation surface 11, and the directivity of the surface waves Ws propagating on the propagation surface 11 can be enhanced. .

Further, as shown in FIG. 4, the distance D between the first rib R1 and the second rib R2 is set substantially equal to the width of the piezoelectric element 30. As shown in FIG. Specifically, the interval D between the first rib R1 and the second rib R2 is the interval between the first opposing surface portion So1 and the second opposing surface portion So2. With this configuration, it is possible to suppress the generation of unnecessary surface waves Ws on portions other than the propagation surface 11 . The fact that the interval D is substantially equal to the width of the piezoelectric element 30 includes not only that the interval D is equal to the width of the piezoelectric element 30 , but also that the width of the propagation surface 11 is equal to the width of the piezoelectric element 30 . That is, it is preferable that the width of the piezoelectric element 30 is equal to or less than the interval D and equal to or greater than the width of the propagation surface 11 .

As shown in FIG. 5, the third rib R3 and the fourth rib R4 protrude in the direction in which the facing surface 12 faces (that is, +Z direction from the base portion 10a). Further, the third rib R3 and the fourth rib R4 are provided in a band shape in the X direction so as to correspond to the facing surface 12, similar to the positional relationship between the first rib R1, the second rib R2, and the propagation surface 11. The third rib R3 and the fourth rib R4 face each other across the facing surface 12 in the width direction (Y direction) of the facing surface 12, as shown in FIG. For example, the main surfaces of the third rib R3 and the fourth rib R4 (surfaces facing the +Z direction) are parallel to the facing surface 12 . For example, the angle formed by the facing surface 12 and the third facing surface portion So3, which is the inner surface of the third rib R3 (the surface facing the -Y direction) and faces the fourth rib R4, is set at a right angle. For example, the angle formed between the fourth opposing surface portion So4, which is the inner surface (the surface facing the +Y direction) of the fourth rib R4 and faces the third rib R3, and the opposing surface 12 is also set at a right angle.

In addition to the first rib R1 and the second rib R2 that are provided so as to correspond to the propagation surface 11, by providing the third rib R3 and the fourth rib R4 that are provided so as to correspond to the opposing surface 12, the propagation body 10 can improve the geometrical moment of inertia, and can improve the resistance to vibration resonance.

The element housing portion 20 is located in the +X direction of the propagating body 10 and houses the piezoelectric element 30, as shown in FIG. For example, the element accommodating portion 20 is made of the same material as the propagating body 10 and is integrally formed. The element housing portion 20 includes a disk portion 21 and a cylindrical body 22 and is provided so as to be continuous with the propagation body 10 .

The disk portion 21 is connected to the propagating body 10 and has an attached surface 21a attached to a side portion of the container 3, which will be described later. The cylindrical body 22 has a cylindrical shape with an outer diameter smaller than the outer diameter of the disc portion 21 and protrudes from the disc portion 21 in the +X direction. A piezoelectric element 30 is accommodated in a space provided inside the cylindrical body 22 . An attachment groove 22a, which is a groove recessed toward the center of the cylinder 22, is formed on the outer peripheral surface of the cylinder 22, and in which the seal member 5 shown in cross section in FIG. 2 is mounted.

The piezoelectric element 30 vibrates the propagating body 10 via the disk portion 21 and causes the propagating body 10 having the propagation surface 11 to generate ultrasonic waves. Specifically, the piezoelectric element 30 generates a surface wave Ws on the propagation surface 11 of the propagating body 10 and an internal propagating wave Wi inside the propagating body 10 as ultrasonic waves. Further, the piezoelectric element 30 detects the surface wave Ws reflected by the reflecting portion 11a and the internal propagation wave Wi reflected by the groove 12a, and outputs a detection signal (voltage signal) indicating the detection result.

The piezoelectric element 30 is composed of a known ultrasonic transducer and has a rectangular parallelepiped shape. The piezoelectric element 30 faces the propagating body 10 with the disk portion 21 interposed therebetween, and generates a surface wave Ws on the propagating surface 11. It is provided so as to protrude across the For example, the surface waves Ws are Schulz waves in the liquid 4 . The surface wave Ws may be a transverse surface acoustic wave (SH-SAW) or the like. The internal propagation wave Wi may be a transverse wave or the like. Further, although detailed illustration is omitted here, the piezoelectric element 30 is electrically connected to the control section 2 via a terminal.

The flange portion 40 shown in FIG. 2 is formed of, for example, a synthetic resin, and has a cylindrical portion 41 opening in the −X direction, a flange 42 protruding in the outer diameter direction of the cylindrical portion 41, and a flange 42. and a hollow cap portion 43 positioned in the +X direction. 2, the cylindrical portion 41 and the seal member 5 are shown in cross section along the radial direction.

The tubular portion 41 surrounds the tubular body 22 of the element housing portion 20 . The tip of the tubular portion 41 faces the outer peripheral edge of the disk portion 21 in the X direction. A sealing material 5 seals between the cylindrical portion 41 and the cylindrical body 22 . The seal member 5 is made of, for example, resin rubber in a ring shape and functions as a packing.

The cap portion 43 has a coupler (not shown). An output terminal (not shown) is positioned inside the coupler. When the external device and the coupler are connected, the external device and the output terminal are electrically connected. For example, the inside of the cap portion 43 accommodates a PCB (Printed Circuit Board) (not shown) that is electrically connected to each of the piezoelectric element 30 and the output terminals, and on which a transmission circuit, a reception circuit, etc., which will be described later, are formed.

The controller 2 schematically shown in FIG. 1 is composed of, for example, a microcomputer, and includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and the like.

A fuel tank mounted on the moving body can be applied to the container 3, and the liquid 4 and the propagating body 10 are stored therein. The container 3 has a bottom portion 3a positioned at the lowest portion thereof, and a side portion 3b provided so as to rise from the peripheral portion of the bottom portion 3a. configuration.

In this case, the propagating body 10 is housed in the container 3 in a belt-like state with the propagating surface 11 facing the bottom 3a of the container 3 (see FIGS. 1 and 2). More specifically, the propagating body 10 here is placed on the bottom portion 3a in a state in which the first rib R1 and the second rib R2 are in contact (surface contact) with the bottom portion 3a as shown in FIG. . The propagating body 10 may be housed in the container 3 so that the first rib R1 and the second rib R2 are separated from the bottom portion 3a.

A hole 3c is provided below the side portion 3b, and the surface wave detector 1 is attached to the side portion 3b of the container 3 with the disk portion 21 closing the hole 3c (see FIG. 2). At this time, the disk portion 21 (element housing portion 20) is positioned outside the side portion 3b with the mounting surface 21a in contact with the side portion 3b, and the entire area of the propagating body 10 is immersed in the liquid 4. become. Focusing on the positional relationship between the facing surface 12, the bottom portion 3a, and the mounting surface 21a, the facing surface 12 is parallel to the bottom portion 3a and orthogonal to the mounting surface 21a. It has become.

Liquid 4 can be gasoline (liquid fuel) stored in container 3 . Here, if the container 3 is a fuel tank mounted on a ship (moving body) that travels on the sea, gasoline is stored under stormy weather conditions (or under conditions where the filler cap seems to be damaged for some reason). It is conceivable that seawater may enter the container 3 where the water is stored. When seawater is mixed in the container 3, a liquid 4 consisting of gasoline and seawater coexists in the container 3. - 特許庁In the following description, among the liquids 4, gasoline will be referred to as the first liquid C1, and seawater will be referred to as the second liquid C2. In this case, the liquid type identification device L and the container 3 containing the liquid 4 and the liquid type identification device L constitute a liquid container.

Here, since the specific gravity of gasoline is about 0.74 and the specific gravity of seawater is about 1.03, the liquid 4 consists of the first liquid C1 having the first specific gravity and The second liquid C2 having a large second specific gravity settles on the bottom 3a of the container 3 due to the action of gravity.

Then, the control unit 2 specifies which of the first and second liquids C1 and C2 the liquid type of the liquid 4 is based on the propagation time of the surface wave Ws detected by the piezoelectric element 30. function as The transmission circuit of the PCB transmits a drive signal to the piezoelectric element 30 to drive the piezoelectric element 30 under the control of the control unit 2 . As a result, the propagating body 10 generates a surface wave Ws and an internal propagating wave Wi. The receiving circuit of the PCB receives detection signals indicating the reflected surface waves Ws and the reflected internal propagation waves Wi from the piezoelectric element 30 and supplies them to the control unit 2 . After receiving the detection signal, the control unit 2 executes processing for identifying the liquid type of the liquid 4 based on the detection signal.

Here, the second liquid C2 is mixed in the container 3, and the propagation surface 11 is positioned below the interface between the first liquid C1 and the second liquid C2 (that is, the propagation surface 11 is immersed in the second liquid C2). By the way, under the condition that the propagation surface 11 is immersed in the second liquid C2 as described above, the propagation surface 11 and the bottom 3a of the container 3 are parallel to each other, and the propagation surface 11 is arranged to face the bottom 3a side. When it is attached to the portion 3b, the first liquid C1 with high viscosity adheres to the propagation surface 11 and becomes difficult to separate from the propagation surface 11, and the second liquid C2 is mixed into the container 3. There is a possibility that it cannot be detected accurately. Such a problem is expected to occur significantly when the propagation surface 11 is formed in a depressed portion between the first rib R1 and the second rib R2 as in the present embodiment.

On the other hand, in the present embodiment, the propagation surface 11, which is a non-flat surface, is provided so as to face the bottom portion 3a side, and is inclined toward the +Z direction (that is, the liquid surface 4a side of the liquid 4) as the distance from the piezoelectric element 30 increases. The first liquid C1 with high viscosity adhering to the propagation surface 11 easily flows toward the bottom surface 15 when the propagation surface 11 is immersed in the second liquid C2. It is designed to come out of the propagating body 10 in a practical manner. Therefore, under the condition that the propagation surface 11 is immersed in the second liquid C2, the adhesion of the first liquid C1 with high viscosity to the propagation surface 11 is suppressed, and as described later, the second liquid C2 flows into the container. 3 can be accurately detected.

Note that the transmission circuit and the reception circuit may be provided in the control section 2 . Also, at least part of the functions of the control unit 2 may be mounted on a PCB provided inside the flange portion 40 .

Here, an example of a liquid type identification method will be described. FIG. 6 shows how the internal propagation wave Wi and the surface wave Ws propagating through the propagating body 10 are input to the piezoelectric element 30 after being reflected by generating the vibration W0.

A time point t0 is a time point when the vibration W0 is generated in the propagating body 10 by driving the piezoelectric element 30 . The vibration W0 causes the propagating body 10 to propagate the surface wave Ws and the internal propagating wave Wi. Time t1 is the time when the internal propagation wave Wi is reflected by the groove 12a and enters the piezoelectric element 30. FIG. A period T1 is an internal propagation wave propagation period T1 from time t0 to time t1. At time t2, the propagation body 10 is immersed in the second liquid C2, and the surface wave Ws propagating on the propagation surface 11 to which the first liquid C1 is not adhered is reflected by the reflecting portion 11a and reaches the piezoelectric element 30. at the time of entry. A period T2 is a surface wave propagation period T2 from time t0 to time t2.

The controller 2 identifies (determines) the liquid type of the liquid 4 based on the surface wave propagation period T2. That is, the control unit 2 identifies the liquid type of the liquid 4 by referring to the data table in which the surface wave propagation period T2 and the liquid type of the liquid 4 are associated. In this case, the control unit 2 refers to the data table and performs processing to specify that the liquid type of the liquid 4 that has settled on the bottom 3a of the container 3 due to the action of gravity is seawater (second liquid C2). . As a result, it is possible to accurately detect that the second liquid C2 has entered the container 3 . Note that the control unit 2 may execute a process of notifying the user of the detected liquid type by means of a notification unit such as a character display (not shown). The principle by which the liquid type of the liquid 4 can be specified based on the surface wave propagation period T2 will be described below.

Since the surface wave propagation period T2 is inversely proportional to the surface wave propagation velocity, the surface wave propagation period T2 becomes shorter as the surface wave propagation velocity increases, while the surface wave propagation period T2 becomes longer as the surface wave propagation velocity decreases. . The surface wave propagation velocity when the propagating body 10 is entirely immersed in the liquid 4 is the sound velocity vl and the density ρl in the liquid peculiar to the liquid 4, and the propagation velocity of the internal propagating wave Wi peculiar to the propagating body 10 determined by vs. That is, when the material of the propagating body 10 is fixed, the surface wave propagation velocity when the propagating body 10 is entirely immersed in the liquid 4 changes depending on the liquid type of the liquid 4 . Therefore, the relationship between the surface wave propagation velocity and the liquid type of the liquid 4 when the propagation body 10 is entirely immersed in the liquid 4 can be obtained by actual measurement, simulation, or the like. By storing the data table in which the surface wave propagation period T2 and the liquid type are associated with each other in the ROM provided in the control unit 2, the liquid type identification device L can determine the surface wave propagation period T2. can be used to identify the liquid type of the liquid 4 (the type of liquid that settles on the bottom 3a is seawater).

The expression that the control unit 2 specifies the liquid type of the liquid 4 based on the surface wave propagation period T2 means that the control unit 2 calculates the surface wave propagation velocity from the surface wave propagation period T2 and calculates the calculated surface wave velocity. It also includes specifying the liquid type of the liquid 4 based on the wave propagation speed. That is, the control unit 2 can identify the liquid type of the liquid 4 based on the calculated surface wave propagation speed by referring to the data table in which the surface wave propagation speed and the liquid type of the liquid 4 are associated. good. In this case, the control unit 2 creates a data table in which the surface wave propagation velocity and the liquid type of the liquid 4 are related, instead of the data table in which the surface wave propagation period T2 and the liquid type of the liquid 4 are related. It suffices if it is stored in the ROM. Further, under the condition that the second liquid C2 is not mixed in the container 3 at all and only the first liquid C1 is stored in the container 3, the controller 2 determines that the liquid type is the first liquid C1. It goes without saying that the specified processing is executed.

As described above, according to the present embodiment, the propagating body 10 is arranged at a position facing the bottom portion 3a and has the propagation surface 11 on which the surface wave Ws propagates, and the propagating body 10 is vibrated to generate the surface wave Ws. a piezoelectric element 30 for detecting the reflected surface wave Ws, and a controller 2 for specifying the type of the liquid 4 based on the propagation time of the surface wave Ws detected by the piezoelectric element 30. The propagation surface 11 is The surface becomes non-flat toward the liquid surface 4a side of the liquid 4 as the distance from the piezoelectric element 30 increases. Therefore, as described above, the adhesion of the first liquid C1 having a high viscosity to the propagation surface 11 is suppressed, and it becomes possible to specify that the second liquid C2 is mixed in the container 3, thereby improving marketability. It is possible to provide a liquid type identification device that

The present invention is not limited by the above embodiments and drawings. Modifications (including deletion of components) can be made as appropriate without changing the gist of the present invention.

For example, any material can be used for the propagating body 10 as long as the surface wave Ws can be propagated satisfactorily. For example, the resin used as the propagating body 10 is not limited to PPS, and may be POM (polyacetal), PBT (polybutylene terephthalate), or the like.

Further, in the above-described embodiment, the propagation surface 11 as the non-flat surface is provided so as to face the bottom 3a of the container 3, and becomes an inclined surface toward the liquid surface 4a of the liquid 4 as the distance from the piezoelectric element 30 increases. However, as a modification of this embodiment, as shown in FIG. 7, instead of the inclined surface, the non-flat surface is formed by a curved surface having a predetermined curvature toward the liquid surface 4a of the liquid 4 as the distance from the piezoelectric element 30 increases. may be made. Even in the case of such a configuration, adhesion of the highly viscous first liquid C1 to the propagation surface 11 is suppressed, and effects similar to those of the above-described embodiment can be obtained.

Further, in the above-described embodiment, the surface wave detecting device 1 is arranged such that the mounting surface 21a of the element accommodating portion 20 is orthogonal to the facing surface 12 (that is, the angle between the mounting surface 21a and the facing surface 12 is 90 degrees). was attached to the side portion 3b of the container 3, but as another modification of this embodiment, the angle θ formed between the facing surface 12 and the attached surface 21a is an acute angle (for example, about 75 degrees). Even in the case of such a configuration, adhesion of the highly viscous first liquid C1 to the propagation surface 11 is suppressed, and effects similar to those of the above-described embodiment can be obtained. In this case, the propagating body 10 may be configured so that the opposing surface 12 and the propagating surface 11 are parallel to each other. It goes without saying that a combined configuration can be employed.

In the above description, descriptions of well-known technical matters are omitted as appropriate in order to facilitate understanding of the present invention.

1 surface wave detector 2 control section (specification section)
3 container (storage member)
3a Bottom 3b Side 4 Liquid 4a Liquid surface 10 Propagating body 10a Base 11 Propagating surface 12 Opposing surface 12a Groove 13, 14 Side 15 Bottom 20 Element accommodating part 21 Disk part 21a Mounting surface 30 Piezoelectric element 40 Flange C1 First Liquid C2 Second liquid R1 First rib R2 Second rib R3 Third rib R4 Fourth rib S1, S2 Curved surface portion Ws Surface wave Wi Internal propagation wave θ Angle

Claims (9)

In a liquid type identification device that is attached to a storage member that stores a liquid and determines the type of the liquid,
a propagating body disposed at a position facing the bottom of the storage member and having a propagating surface that is immersed in the liquid and on which surface waves propagate;
a piezoelectric element that vibrates the propagating body to generate the surface waves and that detects the reflected surface waves;
a specifying unit that specifies the type of the liquid based on the propagation time of the surface wave detected by the piezoelectric element;
A liquid type identification device, wherein the propagation surface is a non-flat surface directed toward the liquid surface side of the liquid as the distance from the piezoelectric element increases. 2. A liquid type identification device according to claim 1, wherein said non-flat surface is formed by an inclined surface or a curved surface. The propagating body includes a base portion having the propagation surface, and a facing surface provided at a position facing the propagation surface across the base portion,
3. A liquid type identification device according to claim 1, wherein the thickness of said base portion along the direction orthogonal to said facing surface gradually decreases with increasing distance from said piezoelectric element. The propagation surface is provided in a strip shape so as to face the bottom side,
The propagating body has a first rib and a second rib that protrude in a direction in which the propagating surface faces and are provided in a band shape so as to correspond to the propagating surface,
4. The liquid seed according to claim 1, wherein the first rib and the second rib are opposed to each other across the propagation surface in the width direction of the propagation surface. Specific device. An element accommodating portion provided so as to be continuous with the propagating body and accommodating the piezoelectric element,
The element housing portion has a mounting surface to be mounted on a side portion of the housing member,
5. A liquid type identification device according to claim 3, wherein an angle formed by said mounting surface and said opposing surface is an acute angle. The liquid is composed of a first liquid having a first specific gravity and a second liquid having a second specific gravity greater than the first specific gravity,
6. The liquid type identification device according to any one of claims 1 to 5, wherein the second liquid settles to the bottom. When the second liquid settles on the bottom and the propagation surface is immersed in the second liquid, the identifying unit determines the type of the liquid based on the propagation time of the surface wave detected by the piezoelectric element. 7. The liquid type identification device according to claim 6, wherein is identified as the second liquid. The storage member is a fuel tank mounted on a mobile body,
8. The liquid type identification device according to claim 6, wherein the first liquid is liquid fuel stored in the fuel tank. a liquid type identification device according to any one of claims 1 to 8;
and a storage member that stores the liquid and the liquid type identification device.

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