JP2006284347A - Apparatus for detecting liquid level and liquid tank having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for detecting a liquid level having a few number of components parts in a liquid tank, capable of improving volume efficiency in the liquid tank, and excellent in the followability of a float and provide a liquid tank having the same. <P>SOLUTION: The liquid level detection apparatus comprises a flat type float having a part to be detected; a guide part oppositely arranged in the direction of movement of the float for restricting the direction of movement of the float; and a detection means for detecting the position of the float. The position of the float vertically moving with variations of a liquid level in the liquid tank and the part to be detected provided for the float are detected by the detection means provided for the holder to detect the liquid height level in the liquid level detection apparatus and improve both volume efficiency in the liquid tank and detection accuracy. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid level detection device for detecting a liquid level in a liquid tank and a liquid tank having the liquid level detection device.

  As a liquid level detection device that detects the level of the liquid level in the liquid tank, a configuration as disclosed in Patent Document 1 is known.

  FIG. 9 is a cross-sectional view showing a conventional liquid level detection device. A liquid constituted by a guide pipe 21 in the liquid tank 20, a float 22 that moves up and down following the liquid level of the liquid in the guide pipe 21, and a detector 23 that is connected to the float 22 and moves up and down in conjunction with the float 22. It is a surface detection device. The liquid level detection device recognizes the level of the liquid level in the liquid tank 20 by visually confirming the vertical state of the detection unit 23 interlocked with the float 22 that moves up and down as the liquid level rises and falls. It is. (See Patent Document 1)

JP 2004-340635 A

  In the liquid level detection apparatus as described above, the float used for detecting the liquid level is columnar and part of it is submerged in the liquid. Also, a holding mechanism such as a guide pipe for guiding the moving direction of the float needs to be provided in the liquid tank so as to be immersed in the liquid. In such a configuration, the ratio of the component parts of the liquid level detection device to the volume in the liquid tank increases, and the volume of liquid that can be stored in the liquid tank decreases.

  Further, since the float and its holding mechanism are immersed in the liquid, when the distance between the float and the holding mechanism is narrowed, the float is fixed to the holding mechanism due to surface tension, and the followability of the float to the liquid surface is deteriorated.

  The present invention solves such problems, and has a liquid level detection device and a liquid level detection device that have few components in the liquid tank, improve volumetric efficiency in the liquid tank, and have good float followability. The object is to provide a liquid tank.

A liquid level detection device for detecting a liquid level level in a liquid tank,
At least a plate-like float having a detected portion, a guide portion arranged to face the movement direction of the float and restricting the movement direction of the float, and a holder having a detecting means for detecting the position of the float The liquid that detects the level of the liquid level by detecting the position of the float that moves up and down with the fluctuation of the liquid level in the liquid tank by the detection means of the holder. A surface detection device is used.

  The float is a liquid level detecting device having a curved portion protruding upward from the liquid level.

  The float is a liquid level detecting device in which a plurality of convex portions protruding toward the liquid level are formed.

  A liquid level detecting device in which the liquid contact surface of the float is formed in a mesh shape or a dendritic shape.

  A liquid level detecting device in which at least the liquid contact surface of the float has water repellency is provided.

  In the liquid level detection device, the guide part of the holder is a concave part, and the float is provided with a convex part that fits into the concave part.

  The guide part of the holder is constituted by a rod-shaped pin, and the float is provided with a through hole through which the rod-shaped pin is inserted and arranged.

  A liquid tank having the liquid level detection device, wherein the liquid level detection device is a liquid tank provided on an upper end surface portion or a lower end surface portion in the liquid tank.

  In the present invention, a holder having a flat plate-like float having a detected portion, a guide portion arranged to face the movement direction of the float and restricting the movement direction of the float, and detection means for detecting the position of the float The level of the liquid level is detected by detecting the position of the float that moves up and down with the fluctuation of the liquid level in the liquid tank by a detecting means provided in the holder for the detected part provided in the float. In particular, since the float has a flat plate shape, it is possible to obtain a float that floats due to the surface tension of the liquid together with the buoyancy caused by the deformation of the liquid surface. Since the float has no part that sinks in the liquid and is thin, a liquid level detecting device with improved volumetric efficiency in the liquid tank can be obtained.

  In addition, since the float has a curved portion protruding upward from the liquid surface, a portion not in contact with the portion in contact with the liquid surface is formed on the liquid surface side of the float. Since the interfaces where the liquid surface and the float contact each other are connected to form a single curved surface, a float that easily utilizes the surface tension and floats on the liquid surface can be obtained. Since the float has no part that sinks in the liquid and is thin, a liquid level detecting device with improved volumetric efficiency in the liquid tank can be obtained.

  In addition, since the plurality of protrusions protruding in the liquid surface direction of the float are formed, the float is in contact with the liquid surface at a plurality of points, and a plurality of interfaces generated between the protrusions of the float and the liquid surface. Since a curved surface is formed by connecting with adjacent interfaces, a float that easily utilizes the surface tension and floats on the liquid surface can be obtained. Since the float has no part that sinks in the liquid and is thin, a liquid level detecting device with improved volumetric efficiency in the liquid tank can be obtained.

  In addition, since the float's liquid contact surface is formed in a mesh or dendritic shape, the length of the float in line contact with the liquid surface can be increased, and a float that easily floats on the liquid surface using a lot of surface tension. Is obtained. Since the float has no part that sinks in the liquid and is thin, a liquid level detecting device with improved volumetric efficiency in the liquid tank can be obtained.

  In addition, since at least the liquid contact surface of the float has water repellency, the surface tension of the liquid with respect to the float can be increased, and a float that easily utilizes the surface tension and floats on the liquid surface can be obtained. Since the float has no part that sinks in the liquid and is thin, a liquid level detecting device with improved volumetric efficiency in the liquid tank can be obtained.

  In addition, since the guide portion of the holder is a recess, and the float is provided with a convex portion that fits into the recess, the position of the detected portion of the float relative to the detection means provided in the holder can be regulated. The level of the liquid level can be accurately detected.

  In addition, since the guide portion of the holder is constituted by a rod-shaped pin, and the float is provided with a through-hole into which the rod-shaped pin is inserted and arranged, the float to be detected with respect to the detection means provided in the holder with a simple configuration. The position of the part can be regulated, and the level of the liquid level can be accurately detected.

  Since the liquid level detection device is a liquid tank provided on the upper end surface portion or the lower end surface portion in the liquid tank, the volume efficiency in the liquid tank is improved and a liquid tank with good detection accuracy is obtained.

  A plate-like float having a detected portion, a guide portion that is arranged opposite to the movement direction of the float and regulates the movement direction of the float, and a holder that has detection means for detecting the position of the float, Liquid that detects the level of the liquid level by detecting the position of the float that moves up and down with the fluctuation of the liquid level in the liquid tank by a detecting means provided in the holder with a detected part provided in the float. The surface detection device is used to improve the volumetric efficiency and detection accuracy in the liquid tank. The present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a liquid level detection device according to a first embodiment of the present invention, which is a diagram arranged in a liquid tank. In FIG. 1, a holder 13 is installed in an opening provided on the upper surface of the liquid tank 1 so as to maintain the airtightness of the liquid tank 1. On the outer surface side of the liquid tank 1 of the holder 13, a hall element 14 as a detection means is attached. A concave portion 13 a is formed on the inner surface side of the holder 13 of the liquid tank 1. The tip of the recess 13a of the holder 13 is in a position recessed from the inner wall surface of the liquid tank. A small flat plate-like float 11 having a width shorter than the width of the inner surface of the liquid tank of the holder 13 is installed in the liquid tank 1, and the float 11 is provided with a convex portion 11a. It is mated. The convex portion 11a is provided with a magnet 12 as a detected portion. The bottom surface of the float 11 is a wetted surface and floats due to surface tension generated at the interface having a contact angle due to wettability between the outer periphery of the float 11 and the liquid surface and buoyancy generated by deformation of the liquid surface of the wetted surface. It is a configuration.

  2A and 2B are diagrams showing a float of the liquid level detection device of the present invention, wherein FIG. 2A is a front view and FIG. 2B is a bottom view. The float 11 has a plate shape, and the planar shape is a circle. The planar shape may be a square shape regardless of this embodiment.

  FIG. 6 is a sectional view showing the liquid level detection device of the present invention, and is a supplementary diagram showing the dimensional relationship among the liquid tank, the holder and the float. As shown in FIG. 6, the length L of the convex portion 11a of the float 11 including the magnet 12 is longer than the length K of the concave portion 13a of the holder. The height H of the float 11 is longer than the distance G between the tip of the holder recess 13 a and the inner wall of the liquid tank 1 on the opposite surface of the holder 13. This prevents the float 11 from being detached from the recess 13 a of the holder 13 regardless of the presence or absence of liquid in the liquid tank 1.

  Next, the operation of the liquid level detection device of the present invention will be described. When the liquid tank 1 is empty, the float 11 is in contact with the bottom surface of the liquid tank in a state of being fitted with the holder 13. When liquid is injected into the liquid tank 1, the outer periphery of the float 11 and the liquid surface form an interface having a contact angle due to wettability. Due to the surface tension of the liquid at the interface and the buoyancy caused by the deformation of the liquid surface occurring on the liquid contact surface of the entire float 11, the float 11 floats in a state of fitting with the holder 13 in accordance with the height of the liquid surface. The height of the liquid level can be detected by the Hall element 14 attached to the holder 13 detecting the distance from the magnet 12 fixed to the convex portion 11a provided on the float 11. Specifically, when the magnet 12 approaches the Hall element 14, the output voltage from the Hall element 14 increases, and conversely, when the magnet 12 moves away, the output voltage decreases. Therefore, the level of the liquid level can be recognized by detecting the output voltage from the Hall element 14.

  When the liquid tank 1 is full, the tip of the convex portion 11a (magnet 12) of the float 11 comes into contact with the holder 13 and stops. Since the width of the float 11 is shorter than the width of the holder 13 on the inner surface of the liquid tank, the float 11 can enter a position recessed from the inner wall surface of the liquid tank of the holder. In the liquid tank 1, the liquid can be stored in all places other than the part where the float 11 enters, and the volume in the liquid tank can be effectively utilized.

  By using the liquid level inspection apparatus having the above-described configuration, the members constituting the liquid level detection apparatus can be configured not to be immersed in the liquid, so that the volume efficiency in the liquid tank is improved and the followability of the float is good. A detection device is obtained.

  FIG. 3 is a view showing another example of the float used in the liquid level detection device of the present invention, in which (a) is a perspective view and (b) is a bottom view. The float 11b in this configuration is a disc having a lattice-like mesh. The mesh may be irregular. A convex portion 11a is provided at the center of the float 11b, and a magnet 12 is attached to the tip thereof. With this configuration, the length of the float 11b in line contact with the liquid surface can be increased, and the length of the interface having a contact angle due to wettability generated between the float and the liquid surface is increased. The action length of the surface tension of the generated liquid is increased, and a float that easily floats on the liquid surface is obtained together with the buoyancy due to the deformation of the liquid surface that occurs on the liquid contact surface of the entire float 11.

  FIG. 4 is a bottom view showing another example of the float used in the liquid level detection device of the present invention. The float used in the liquid level detection device of the present invention may be formed in a dendritic shape as shown in the figure, and the outer shape is not limited to a circle but may be an indeterminate shape.

  FIG. 5 is a front view showing another example of the float used in the liquid level detection device of the present invention. The float 11c in this configuration is formed with a curved portion so as to protrude in the direction opposite to the liquid level. With this configuration, a portion not in contact with the liquid surface is formed on the liquid surface side of the float 11c. Interfaces with contact angles due to wettability generated at the part where the liquid level and the float come into contact are connected at the part where the liquid level and the float are not in contact, forming a single curved surface on the liquid level below the float. Thus, the surface area of the surface tension is increased, and a float that easily floats on the liquid surface can be obtained together with the buoyancy caused by the deformation of the liquid surface.

  Moreover, you may form several convex part which protrudes in a liquid level direction in each float shown in FIGS. As a result, the float contacts the liquid surface at multiple points, so the interface with the contact angle due to wettability that occurs between the float and the liquid surface is connected to the adjacent interface to form a single curved surface, and the surface tension In addition to the buoyancy caused by the deformation of the liquid surface, a float that easily floats on the liquid surface is obtained.

  In addition, at least the liquid contact surface of each float shown in FIGS. 1 to 5 may be formed with Teflon (registered trademark) or may be processed with a Teflon film or the like (Teflon is a registered trademark). As a result, the surface tension of the liquid with respect to the float can be increased, and the contact angle due to the wettability of the interface between the float and the liquid surface can be increased, thereby increasing the effect of the surface tension and the deformation of the liquid surface. Combined with buoyancy, a float that floats easily on the liquid surface is obtained.

  In FIG. 1, the magnet 12 that is the detected portion of the float 11 is at the tip of the convex portion 11 a, but may be below the convex portion 11 a of the float 11, or may be directly mounted on the float 11.

  In FIG. 1, the Hall element 14 serving as a detection unit is located on the upper portion of the holder 13, but may be located on the side portion of the holder 13.

  In FIG. 2, the holder 13 is installed on the upper surface of the liquid tank 1, but the holder 11 may be installed on the lower surface of the liquid tank 1, and the float 11 may be disposed so as to fit therewith.

  FIG. 7 is a cross-sectional view showing a liquid level detection device according to a second embodiment of the present invention, and is a view arranged in a liquid tank. FIG. 8 is a perspective view of a float used in the liquid level detection device of the second embodiment. The float 11d is provided with a circular through hole 11e. The float 11d is provided with a plurality of convex portions 11f projecting in the liquid surface direction and a magnet 12 as a detected portion attached to the center of the float 11d. In FIG. 7, a holder 13 is installed in an opening provided on the upper surface of the liquid tank 1 so as to maintain the airtightness of the liquid tank 1. On the outer surface side of the liquid tank 1 of the holder 13, a hall element 14 is attached as detection means. On the inner surface side of the liquid tank 1 of the holder 13, a rod-shaped pin 15 that serves as a guide portion of the float 11 d extends to the inner surface of the liquid tank that faces. In the liquid tank 1, a float 11d is arranged by inserting a rod-like pin 15 extending from the holder 13 into a through hole 11e of the float 11d. Since the rod-shaped pin 15 is thin, it hardly occupies the volume in the liquid tank 1.

  Next, the operation of the liquid level detection device of the present invention will be described. When the liquid tank 1 is empty, the float 11d is grounded to the bottom of the liquid tank. When the liquid is injected into the liquid tank 1, a plurality of interfaces having contact angles due to wettability are formed between the plurality of convex portions 11f of the float and the liquid surface. The interface is connected to an adjacent interface to form a curved surface. The float 11d floats in accordance with the height of the liquid surface in combination with the surface tension of the liquid in the curved surface portion and the buoyancy due to the deformation of the liquid surface. The level of the liquid level is detected by a magnet 12 which is a detected portion fixed to the float 11d and a hall element 14 which is a detecting means attached to the holder 13.

  By setting it as the liquid level inspection apparatus of the said structure, the volume efficiency in a liquid tank improves and the liquid level detection apparatus with the favorable followability of a float is obtained.

  The float 11d shown in the second embodiment is not limited to this, and may be in the form shown in the first embodiment.

  Also in the second embodiment, the liquid tank 1 and the holder 13 may be integrally formed. In this case, the detection means may be directly attached to the liquid tank 1 or may be attached separately.

1 is a cross-sectional view showing a liquid level detection device according to a first embodiment of the present invention, and is a diagram arranged in a liquid tank. It is a figure which shows the float of the liquid level detection apparatus of this invention, (a) is a front view, (b) is a bottom view. It is a figure which shows the other example of the float used for the liquid level detection apparatus of this invention, (a) is a perspective view, (b) is a bottom view. The bottom view which shows the other example of the float used for the liquid level detection apparatus of this invention The front view which shows the other example of the float used for the liquid level detection apparatus of this invention It is sectional drawing which shows the liquid level detection apparatus of this invention, and is a supplementary figure which shows the dimensional relationship of a liquid tank, a holder, and a float It is sectional drawing which shows the liquid level detection apparatus of 2nd Example of this invention, and is the figure arrange | positioned in a liquid tank The perspective view of the float used for the liquid level detection apparatus of 2nd Example of this invention Sectional view showing a liquid level detection device according to the prior art

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid tank 11 Float 11a Convex part 11b Float 11c Float 11d Float 11e Through hole 11f Convex part 12 Magnet 13 Holder 13a Concave part 14 Hall element 15 Rod-shaped pin 20 Liquid tank 21 Guide pipe 22 Float 23 Detection part

Claims (8)

A liquid level detection device for detecting a liquid level level in a liquid tank,
at least,
A flat float having a detected portion;
It is arranged to be opposed to the movement direction of the float, and includes a holder having a guide part that regulates the movement direction of the float, and a detection unit that detects the position of the float,
Detecting the level of the liquid level by detecting the position of the float that moves up and down with the fluctuation of the liquid level in the liquid tank by a detecting means provided in the holder for the detected part provided in the float. A liquid level detection device characterized by the above.   The liquid level detection device according to claim 1, wherein the float has a curved portion protruding upward from the liquid level.   The liquid level detection device according to claim 1, wherein the float has a plurality of protrusions protruding toward the liquid level.   The liquid level detection apparatus according to claim 1, wherein a liquid contact surface of the float is formed in a mesh shape or a dendritic shape.   The liquid level detection device according to claim 1, wherein at least a liquid contact surface of the float has water repellency.   The liquid level detection according to claim 1, wherein the guide portion of the holder is a concave portion, and the float is provided with a convex portion that fits into the concave portion. apparatus.   The guide part of the said holder is comprised by the rod-shaped pin, The through-hole which inserts and arrange | positions the said rod-shaped pin is provided in the said float, The any one of Claims 1-5 characterized by the above-mentioned. Liquid level detection device. A liquid tank having the liquid level detection device according to any one of claims 1 to 7,
A liquid tank having a liquid level detection device, wherein the liquid level detection device is provided on an upper end surface portion or a lower end surface portion in the liquid tank.

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