JPH11264753A - Liquid level detecting structure of liquid tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the liquid level with a simple and inexpensive structure never influenced by structure, strength or the like by providing a temperature indicating means sensing the temperature of a liquid and discoloring according to it on the outer surface of a tank, and detecting the level within the tank by the discoloration of the temperature indicating means. SOLUTION: A coating material using a pigment having chromatism phenomenon of reversibly changing the color according to thermal stimulation is applied to the outer surface of the side plate 4a of a tank body 4 to form a temperature indicating means 6. When the level 5a of a fuel 5 injected into the tank body 4 reaches the position of the temperature indicating means 6, the temperature indicating means 6 senses the temperature of the fuel 5 through the side plate 4a to change the area part X contact with the fuel 5, and according to the rise of the level 5a, the boundary part 6c between discoloration (coloring) and color extinguishment of the temperature indicating means 6 is also raised. Thus, the injection of the fuel 5 is continued while carefully observing the temperature indicating means 6, and stopped when the boundary part 6c reaches a full-tank display line 6b, whereby the full-tank can be confirmed to prevent the overflow.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for detecting the liquid level of a liquid tank, and more particularly, to detecting the liquid level of a liquid by using a temperature indicating means which senses the temperature of the liquid and changes its color. Liquid level height detection structure.

[0002]

2. Description of the Related Art A fuel tank, which is a liquid tank (hereinafter may be simply referred to as a "tank"), for example, is provided in a construction machine and stores fuel. A liquid level gauge is provided which can visually detect the fuel level so as not to overflow and also to confirm a specified "full state".

The following structure is used as a typical liquid level gauge. (1) As shown in FIG. 3, a transparent glass tube 2 for guiding a part of the liquid inside the tank 20 is provided on the side surface of the tank 20.
2 is set in the direction in which the liquid surface 20 a rises and falls so that the liquid surface 22 a in the glass tube 22 is at the same level as the liquid surface 20 a in the tank 20. A method using a liquid level tube for checking the liquid level 20a. (2) As shown in FIG.
A method using a long-hole window in which a long-hole window 24 is opened in the direction in which the liquid surface 20a moves up and down, a transparent plate 26 such as a glass plate is fitted, and the liquid surface 20a in the tank 20 is confirmed through the transparent plate 26.

[0004]

The conventional liquid level gauge of the above-described embodiment has the following problems to be solved.

(1) Since a hole for introducing liquid or a long hole with a transparent plate is provided in a part of the structure of the tank, the tank is designed and manufactured in order to maintain the watertightness (airtightness) of the tank. Requires special consideration. In addition, due to the structure of the tank, the place where the liquid level gauge is installed is often restricted.

(2) Parts for visual recognition, such as a transparent tube and a transparent plate, are added to the tank structure as the original liquid container. Great care must be taken to ensure the strength of the tank and additional structures.

[0007] The present invention has been made in view of the above-mentioned facts, and its technical problem is that there is no need to drill holes or the like in the tank, and there is little restriction on the structure of the tank. An object of the present invention is to provide a structure for detecting the liquid level of a liquid tank, which does not affect the strength and the like, is simple and inexpensive.

[0008]

According to the present invention, in order to solve the above-mentioned technical problems, a temperature indicating means for sensing the temperature of the liquid and discoloring the liquid is provided on an outer surface of a tank containing the liquid.
The color change of the temperature indicating means is visually confirmed to detect the liquid level.

[0009] The temperature indicating means is a means for changing the color by sensing the temperature, for example, changing the color by sensing the temperature of the stored liquid, and discoloring or changing to another color when there is no liquid.
Specifically, paint using a pigment having a chromism phenomenon in which the color reversibly changes in response to external thermal stimulus,
All means such as seals and tapes.

That is, according to the present invention, as a structure for detecting the liquid level in the liquid tank which solves the above technical problem, the liquid level of the liquid contained in the liquid tank is determined by using the outer surface of the liquid tank. Wherein the temperature of the liquid is sensed by a temperature indicating means which changes color by sensing the temperature of the liquid.

In the structure for detecting the liquid level in a liquid tank according to the present invention, the liquid level in the tank is changed by a temperature indicating means provided on the outer surface of the tank to change the color by sensing the temperature of the liquid through the wall of the tank. Is detected. Therefore, it is not necessary to make a hole in the tank for providing the liquid level gauge and to add components as in the conventional case.

In a preferred embodiment, a temperature indicating paint is used for the temperature indicating means. The temperature indicating paint is applied to the liquid tank.

[0013] Therefore, since the liquid level detecting structure is constituted by using the temperature-indicating paint, a simple and inexpensive liquid level detecting structure is provided.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a fuel tank for storing fuel according to an embodiment of the present invention; Then, it will be described in more detail.

Referring to FIG. 1 and FIG. 2, a fuel tank indicated generally by reference numeral 2 comprises a tank body 4, a temperature indicating means 6 provided on a side plate 4 a of the tank body 4, and a tank body 4.
A cap 8 detachably attached to the tip of an injection pipe 4b provided at the upper part of the tank, a drain cock 10 openable and closable provided at the lower part of the tank body 4, and a fuel supply destination provided at a lower part of the tank body 4 Is provided with a supply cock 12 that can be opened and closed freely and connected to the supply pipe line. Injection tube 4b
Is provided with a strainer 14.

The tank body 4 is formed by welding thin steel plates to each other and integrally forming a substantially rectangular parallelepiped hollow container (FIG. 1).
Has a width in a direction perpendicular to the paper surface). The cap 8 attached to the injection pipe 4b on the upper part of the tank body 4 is removed, and foreign matter is injected into the tank body 4 from the injection port formed by the injection pipe 4b using a fuel injection nozzle or the like. Inject into the tank body 4 through the strainer 14 provided so as not to enter. Thus, the fuel 5 is accommodated in the tank main body 4, and the liquid level 5a is formed.

The temperature indicating means 6 is provided by applying a temperature indicating paint (the temperature indicating paint will be described later in detail) to the outer surface of the side plate 4a forming one side surface of the tank body 4.
The temperature-indicating paint is a rectangular temperature-indicating paint application area 6a having a length L and a width W in the fluctuation direction of the liquid level 5a of the fuel 5 as indicated by an arrow 7.
It is applied to. At the upper end of the temperature paint application range 6a, a full tank display line 6b is marked, and the specified “full tank” position of the fuel tank 2 is displayed.

As the temperature indicating paint used for the temperature indicating means 6, a paint using a pigment having a chromism phenomenon in which the color reversibly changes in response to a thermal stimulus is used. The temperature-indicating paint develops color, for example, on the low temperature side of the set reference temperature, and disappears on the high temperature side. The type of color to be developed is arbitrarily selected, but if the fuel tank is yellow, for example, black can be used to make it easy to see. The reference temperature, which is the boundary temperature between color development and color erasure, has a temperature range of ± α ° C. between color development and color erasure for complete color change. The reference temperature is set to T ° C based on the temperature T ° C of the fuel injected into the tank.
If it is set to, the color develops completely at T ° C + α ° C, and T °-α ° C
Completely decolorize with. Since the reference temperature T ° C. can be appropriately selected, it is determined based on the temperature condition around the fuel tank 2 and the temperature condition of the injected fuel. As the paint, for example, a product name of "Thermo Paint" of NOF Engineering Co., Ltd. is commercially available.

With reference to FIG. 1, the operation of the liquid level detecting structure of the fuel tank 2, which is the liquid tank as described above, will be described.

(1) Inlet cap 8 of fuel tank 2
When the fuel is injected from the injection port using an injection nozzle or the like while watching the temperature indicating means 6, a liquid level 5 a is formed by the injected fuel 5, and the liquid level 5 a increases with the injection amount of the fuel 5. It rises together.

(2) When the liquid level 5a rises to the position where the temperature indicating means 6 is provided, the temperature indicating means 6
Is sensed through the steel-made side plate 4a forming the tank main body 4, and the portion of the temperature indicating means 6 that contacts the fuel 5 via the side plate 4a is discolored. For example, the side plate 4 of the tank body 4
If the temperature of the fuel a is lower than the reference temperature T ° C. and the temperature of the fuel 5 is higher than the reference temperature T ° C., the liquid level 5 a
Is located below the position of the temperature indicating means 6, the temperature indicating means 6 is colored. When the liquid level 5a rises and reaches the position of the temperature indicating means 6, the fuel 5 passes through the side plate 4a of the temperature indicating means 6.
Is erased, and the boundary 6c (corresponding to the liquid level 5a) between the color development and the decoloring rises with the rise of the liquid level 5a. That is, the lower area of the temperature-indicating paint application range 6a indicated by X in FIG. 1 is erased . Conversely, the side plate 4a of the tank body 4
When the temperature of the fuel 5 is higher than the reference temperature T ° C. and the temperature of the fuel 5 is lower than the reference temperature T ° C., when the liquid level 5 a is below and not at the position of the temperature indicating means 6, the temperature indicating means 6 decolorizes. ing. Then, when the liquid level 5a rises and reaches the position of the temperature indicating means 6, the portion of the temperature indicating means 6 which comes into contact with the fuel 5 via the side plate 4a develops a color, and in accordance with the rise of the liquid level 5a, a boundary portion 6c between the decoloring and the coloring. (Corresponding to the liquid level 5a). That is, the lower area of the temperature-indicating paint application range 6a indicated by X in FIG. 1 is colored.

(3) When the injection of the fuel 5 is continued, the liquid level 5a
As the temperature rises, the boundary 6c between the coloring and decoloring of the temperature indicating means 6
Also rises. Therefore, the boundary portion 6c is filled with the full display line 6b.
, The injection of the fuel 5 is stopped. Therefore, if the temperature indicating means 6 is closely watched, overflow of the fuel 5 from the injection port when the fuel 5 is injected into the fuel tank 2 can be prevented, and a specified “full state” can be confirmed.

(4) The structure for detecting the liquid level of the liquid tank according to the present invention is formed by providing a temperature indicating means coated with a temperature indicating paint on the outer surface of the tank, so that the structure is simple.
In addition, since it is not necessary to add components such as a hole to the tank, a transparent tube, and a transparent plate, there is no effect on the watertightness (airtightness) or strength of the tank. Furthermore, there are few restrictions on the installation location of the temperature indicating means. Therefore, the structure for detecting the liquid level of the liquid tank can be provided with a simple structure and at low cost.

(5) In particular, the structure for detecting the liquid level of a liquid tank according to the present invention is suitable for a fuel tank of a construction machine. That is, in construction machinery, in order to properly perform construction work, at the start of work every day, at the end of work, or in the middle of work, the fuel tank is frequently filled up at the operation site so that the fuel tank becomes "full". Fuel is refilled frequently. This filling operation is performed not by monitoring the remaining amount of fuel in the tank provided in the driver's cab, but by looking at the liquid level gauge provided in the tank. Further, the fuel tank of the construction machine is subjected to severe vibration, impact and the like. Therefore, the liquid level detecting structure of the liquid tank according to the present invention has a simple structure, does not impair the strength of the tank, and is resistant to damage. Can be.

As described above, the present invention has been described in detail based on the embodiments. However, the present invention is not limited to the above-described embodiments, and can be variously modified or modified within the scope of the present invention. It is.

(1) In the embodiment of the present invention, the temperature indicating paint is directly applied to the liquid tank body as the temperature indicating means. However, the temperature indicating paint is applied in advance to a material having good heat conductivity, such as a copper plate, and the temperature indicating paint is applied. May be attached to the liquid tank.

(2) Further, in the embodiment of the present invention, the temperature indicating paint of the temperature indicating means is provided in a portion close to "full" of the liquid tank in a range of L in the vertical direction (FIG. 1). ), The range of L can be extended to below the tank so that the liquid level can be detected from a low position to a “full” part.

(3) Further, in the embodiment of the present invention, the liquid tank is made of a steel plate, but the liquid tank is formed by plastic molding or the like, so that the heat transfer between the liquid and the temperature indicating means is performed. In the case where the heat resistance is poor, it is preferable that a steel plate having good thermal conductivity, for example, is buried in the forming stage in advance in the portion where the temperature indicating means is provided.

[0029]

According to the structure for detecting the liquid level of a liquid tank constructed in accordance with the present invention, it is not necessary to make a hole in the tank, and there is little restriction on the installation location in the tank. Does not affect structure, strength, etc.
A structure for detecting the liquid level of a liquid tank, which is simple and inexpensive, is provided.

[Brief description of the drawings]

FIG. 1 is a side view of a fuel tank provided with a temperature indicating means, which is a liquid level detection structure of a liquid tank configured according to the present invention.

FIG. 2 shows a portion provided with the temperature indicating means of FIG.
The enlarged sectional view seen in the direction.

FIG. 3 is an explanatory diagram of a liquid level gauge using a conventional liquid level tube.

FIG. 4 is an explanatory view of a liquid level gauge using a conventional long hole window.

[Explanation of symbols]

 2: Fuel tank (liquid tank) 4: Tank body 5: Fuel (liquid) 5a: Liquid level 6: Temperature indicating means 6a: Temperature indicating paint application range 6b: Full tank display line 6c: Boundary part

Claims (3)

[Claims] 1. The liquid tank according to claim 1, wherein the liquid level of the liquid contained in the liquid tank is detected by a temperature indicating means provided on an outer surface of the liquid tank to change the color by sensing the temperature of the liquid. Liquid level detection structure. 2. The structure for detecting a liquid level in a liquid tank according to claim 1, wherein a temperature indicating paint is used for said temperature indicating means. 3. The structure for detecting a liquid level of a liquid tank according to claim 1, wherein said temperature indicating paint is applied to said liquid tank.