JPH09323799A - Structure for detecting liquid level and water in storage tank such as underground tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure which is simpler and highly accurately detects an amount of remainder and water in a underground tank of a gas station or the like. SOLUTION: The underground tank is equipped with a float 3 which moves according to the level of a liquid in a tank main body 1, and a detector 2 which can calculate an amount of the movement of the float 3 by detecting the rotation of a drum 2a to which a float tape 3a connected to the float 3 is joined. In the case, a guide 5 is provided in the tank main body 1 and also the float 3 is joined to the guide 5 so as to move upward and downward along it. A water detection float, which is fitted on the guide 5 from outside so as to move upward and downward and incorporates a magnet, is provided below the float 3, and in the guide 5 a contact which is actuated by the magnet is provided in a position corresponding to the allowable level of water entering the tank. Further, the detector 2 is equipped with a system for AD-converting a liquid- level detection signal and digitally displaying an amount of remainder in the tank.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underground tank such as a gas station, and more particularly to a liquid level and water detection structure capable of surely detecting the oil level and the state of intruding water.

[0002]

2. Description of the Related Art In underground tanks such as gas stations,
It is usual to have a fuel gauge for detecting the amount of oil, and various fuel gauges have been conventionally used. As such a fuel gauge, a float type is widely known, which is the simplest and easiest to install, and which floats and sinks according to the liquid level and converts the floating and sinking amount into the remaining amount.

FIG. 6 is a schematic vertical view showing an equipment structure for detecting the remaining amount using such a float, and FIG. 7 is a transverse sectional view showing an internal structure of the detector.

At the upper end of the tank 51, for example, Japanese Patent Publication Sho 60
The detector 52 applicable as a digital oil level gauge as described in JP-A-35612 is provided.
A tape drum 53 is rotatably incorporated in the apparatus 2, and a float tape 54 with a scale is wound around the tape drum 53. The float tape 54 is connected to a float 55 that moves up and down according to the liquid level, and a guide roller 56 is provided in a path between the float tape 54 and the tape drum 53, and the weight of the weight 53a connected to the rotation shaft of the tape drum 53. The tape drum 53 can be rotationally driven according to the elevation of the float 55 by utilizing the balance of The potentiometer 57 for mechanically detecting the rotation amount of the tape drum 53 is provided, and the float 55 is output by outputting a signal based on the rotation amount.
The level, that is, the liquid level is output and digitally displayed on the fuel gauge.

On the other hand, the filling pipe that is connected to the underground tank for unloading oil from the tank truck is a hose connecting portion on the ground side, and the lower end is extended to near the bottom of the underground tank. It is normal. The purpose of extending the injection pipe to the vicinity of the bottom in this way is to prevent undulation at the liquid surface during unloading.
Further, the float 55 type fuel gauge shown in FIG. 6 is easily affected by waving, so that no pipe or the like is provided in the vicinity of the float 55 so that the float 55 does not interfere with the floating and sinking operation. It is designed to operate stably.

As described above, by preventing waviness on the liquid surface and by not providing the pipe in the vicinity, stable operation of the float can be ensured, so that the operation of the float is stabilized. No guides, etc. were required to let them do.

[0007]

However, in recent years,
Equipment has come to be adopted in which all piping is stored in one box to reduce construction costs. In such pipes, suction pipes or the like for sending oil to the ground-side oil dispenser are often inserted into the tank as so-called drop pipes, and such drop pipes should be placed near the fuel gauge. become. In addition, for the delivery of oil to the oil dispenser, an in-oil pump that is operated by immersing it in a liquid has come to be widely used because of its high discharge performance. It may be a design condition that must be placed nearby.

When the drop pipe is arranged near the fuel gauge as described above, the float is flown when the liquid surface is wavy, and the float is wound around the drop pipe, and the float does not operate. There is a fear.

For example, in the case of the detector 52 shown in FIG. 6, since the rotation amount of the tape drum 53 in response to the floating / sinking movement of the float 55 is converted as the remaining amount,
If the operation of the float 55 is unstable, it affects the accurate detection of the remaining amount. Since the float tape 54 may roll laterally, the guide roller 56 has a flange 56 for guiding the float tape 54 in the width direction.
Rolling is prevented by providing a. However, when such a flange 56a is provided, a resistance against the movement of the float tape 54 acts, so that the floating amount of the float 55 and the tape drum 5 are increased.
3 does not match the rotation amount, and as a result, the accuracy of remaining amount detection decreases.

Further, since water having a larger specific gravity than oil accumulates at the bottom of the underground tank, there are some which use the conductivity of water to detect this water. This is to detect the amount of water by facing the probe to the detection plate installed on the bottom of the tank.For example, even if the water in the tank is small enough that water does not adhere to the tip of the probe, unloading oil Water suddenly diffuses due to the momentum of the oil at the start of squeezing, causing water to attach to the tip of the probe and triggering an alarm. Therefore, malfunctions tend to occur frequently, which poses a serious problem in terms of reliability.

As described above, in the conventional tank equipment, instability of floating operation of the float remains, which affects the highly accurate detection of the remaining amount, and there is still a problem to be improved in the detection of the infiltrated water.

The problem to be solved by the present invention is to provide a residual quantity and water detecting structure which can detect the residual quantity and water with a simpler structure and with high accuracy in an underground tank such as a gas station.

[0013]

SUMMARY OF THE INVENTION The present invention detects the rotation of a float which responds to the liquid level inside a tank body and a drum which is connected to a float tape connected to the float, and calculates the movement amount of the float. In an underground tank equipped with a possible detector, a guide is provided inside the tank main body, the float is connected to the guide so as to be able to move up and down, and the guide is vertically inserted to the guide below the float. In addition, a water detection float having a built-in magnet is provided, and the guide is provided with a contactor that can be operated by the magnet at a position corresponding to an allowable water penetration level in the tank.

Further, the detector may be provided with a system for AD-converting the liquid level detection signal and digitally displaying the remaining amount in the tank.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Since the float for detecting the remaining amount of oil and the water detection float for detecting the invading water accumulated at the bottom of the tank are also connected to the guides and moved up and down, the liquid level of The float for remaining amount detection can be held without being affected by undulations. Therefore, the swaying motion of the float tape connected to the float is also suppressed, and the liquid level detection is reliably performed by the rotation of the drum that winds the float tape.

Further, since one guide is used for both the remaining amount detection and the water detection, it is only necessary to attach the guide portion to the existing equipment, and it is possible to greatly contribute to the equipment improvement.

Further, the detector has a structure in which the remaining amount in the tank is digitally displayed based on the liquid level detection signal.
The remaining amount can be notified with a numerical value with high accuracy. And since the float does not shake, the detection accuracy of the liquid level by the detector is significantly improved compared to the case where no guide is provided, so the reliability of the displayed value of the remaining amount in the tank that is finally displayed digitally is also high. Get higher

[0018]

1 is a vertical cross-sectional view showing an essential part of a liquid level and water detection structure of the present invention, and a tank for storing gasoline or other oil will be described as an example.

In the figure, at the upper end of the tank main body 1, Japanese Patent Publication No. 60-35612 described in the section of the prior art of the fuel gauge.
A detector 2 having a detection system similar to that described in Japanese Patent Publication is provided. This detector 2 has a function of detecting the operation amount of the float 3 floating and sinking due to the fluctuation of the liquid level of the remaining amount of oil in the tank main body 1 by an analog signal, and then converting it into a digital signal and displaying it on the measuring instrument. It has been conventionally adopted in the field of measuring instruments.

That is, as described in Japanese Examined Patent Publication No. 60-35612, a change in the liquid level in a horizontal cylindrical gasoline tank is optically detected by a photoelectric sensor or the like, or the liquid level is detected. It is possible to apply a detection system including a circuit that mechanically detects by the action of the float that floats and sinks in response to the operation, electrically outputs detection signals by these, and converts and amplifies the voltage signal in the voltage signal conversion unit. In such a detection system, by connecting to the analog conversion circuit of the liquid level by the AD conversion circuit and providing the non-linear conversion circuit as the polygonal curve calculation circuit, the approximation along the curve of the display graph of the missing circle function is performed. It is possible to obtain a polygonal line, and it is possible to display the liquid volume in the horizontal type inner cylindrical gasoline tank clearly and clearly and accurately in a digital display. And
Especially, compared with the analog display, the display accuracy can be greatly improved and the liquid volume in the tank can be accurately grasped.

Inside the detector 2, there is rotatably provided a tape drum 2a for winding a float tape 3a having a float 3 connected to its lower end, and as shown in FIG.
Similarly, two rod-shaped guide shafts 2b and 2c for guiding the float tape 3a to the peripheral surface of the tape drum 2a are rotatably provided. Further, a potentiometer 2d for detecting the rotation amount of the tape drum 2a is incorporated,
The rotary shaft 2e of the tape drum 2a and the potentiometer 2d are connected to each other by a gear train 2f.
A weight tape 4a having a weight 4 attached to the lower end is wound around e.

Further, the detector 2 has its lower end at the tank body 1
A guide 5 having a cross-sectional shape that is opened so as to face the inside of the tank, the upper end of which is inserted into the detector 2 and the lower end of which is seated on the bottom of the tank body 1, is arranged in a vertical posture. The guide 5 is made of a steel pipe or the like having a rectangular hollow cross section, and the guide 5 will sway even if the liquid surface in the tank body 1 is wavy. It is fixed to the main body 1.

As shown in FIG. 1, the tank body 1 is provided with a suction pipe 1a extending to the bottom surface thereof.
Allow oil to be supplied from a to each weighing machine on the ground.

The float 3 is connected to the guide 5 by a hook 6 so as to be movable up and down. As shown in FIG. 3A, the hook 6 is formed by bending a steel wire into a concave shape, for example, and includes a base 6a and a pair of arms 6b at both ends thereof. The length of the base 6a is sufficiently longer than the length of one side of the guide 5 having a rectangular cross section, and the arm 6b is slightly longer than the length of one side of the guide 5. Then, as shown in FIG. 3B, the base portion 6a is fixed to the peripheral surface of the float 3 by welding or the like so that the base portion 6a has a posture having an intersection angle of 45 degrees with respect to the axis of the float 3. .

In such a mounting structure of the hook 6 to the guide 5, as shown in FIG. 4, since the length of the base portion 6a is sufficiently longer than the length of one side of the guide 5, the arm 6b is provided.
Are engaged with the surfaces of the two sides facing each other. Since the base 6a is inclined 45 degrees with respect to the axis of the float 3, when the arm 6b is engaged with the two surfaces of the guide 5 in this manner, the axis of the float 3 is aligned with the guide 5.
It becomes a posture orthogonal to the
Be maintained in the posture. That is, since the float 3 has a hollow cylindrical shape, when it floats on oil, it floats in a posture in which its axis is parallel to the liquid surface. Therefore, the hook 6 is placed in the middle of the axial length of the float 3. If properly provided, even if the hook 6 is externally inserted into the guide 5, the float 3 is set so that the arm 6b of the hook 6 does not hit the surface of the guide 5 strongly in the posture of FIG. Can be floated in oil in a horizontal position.

As described above, since the guide 2 is arranged in a vertical posture in the tank body 1 and the float 3 is connected to the guide 2 by the hook 4, even if there is a waviness generated during unloading or the like. The float 3 can be restrained to the guide 2 side so that only the floating / sinking operation is performed. Therefore, even if the drop pipe, the in-oil pump, or the like is installed nearby, the float 3 can maintain a stable movement and can reliably detect the remaining amount.

That is, in the conventional example shown in FIG. 6, since the float 55 is simply suspended from the detector 52 by the float tape 54, the float 55 moves around due to the corrugation of the liquid surface. Sway. On the other hand, in the present invention, the float 3
Is lifted up and down while being restrained by the guide 5 via the hook 6, the float 3 will not be swept even if the liquid surface undulates, and can be moored below the detector 2 at all times.

Therefore, even when the liquid level rises and the float tape 3a is wound around the tape drum 2a, the float tape 3a operates without swaying, so that the rise of the liquid level can be accurately rotated. It can be transmitted, and the detection value of the liquid level fluctuation by the potentiometer 2d can be maintained with high accuracy. Also, float tape 3a
Since the lateral sway of the guide tape is suppressed, the guide shafts 2b and 2c do not need flanges for restraining both ends of the float tape 3a in the width direction, and the guide shafts 2b and 2c can be rod-shaped as they are. And float tape 3
Since “a” only slides on the peripheral surfaces of the guide shafts 2b and 2c and is not subjected to resistance by the flange, the responsiveness to changes in the liquid level becomes faster, and the detection accuracy of the remaining amount can be further improved.

If the hook 6 is a steel wire rod having a circular cross section, the base 6a and the arm 6b slide on the surface of the guide 5 in line contact with each other. Therefore, the resistance of the float 3 to floating and sinking operations is small, and the responsiveness to changes in the liquid level is high.

Further, in the present invention, the water detecting float 7 is provided below the float 3 around the guide 5. The water detection float 7 is for detecting water having a specific gravity larger than that of oil that has entered the tank body 1 and accumulated at the bottom for some reason. When the water reaches a certain limit value, an alarm is issued. Is included in the system that was designed to emit.

That is, the water detection float 7 is an annular body having a shape through which the guide 5 penetrates, and as shown in the schematic longitudinal sectional view of FIG. It does not float with the specific gravity of oil, and has a volume and weight that only float when immersed in invading water. On the other hand, on the lower end side of the guide 5, the water detection float 7
Is mounted and a contactor 5a is incorporated at a position corresponding to the height at which the alarm for water intrusion should be issued. This contactor 5a is designed to output a signal to the control unit by closing the contact when the water detection float 7 floats up due to the pool of invading water and the magnet 7a reaches the corresponding height, thereby issuing an alarm. Is.

In this way, one guide 5 is attached to the float 3
It can be used both as an alarm when water enters by the combination of the guide member and the water detection float 7. Further, since the water detection float 7 can perform a stable floating / sinking operation without being affected by undulations by the guide 5, the water detection float 7 can reliably perform water detection that is much more stable than the water detection using conductivity by the probe. Therefore, it is possible to prevent the obstacle caused by the invasion of water into the tank body 1.

[0033]

According to the present invention, it is possible to detect the remaining amount of oil and the water intrusion using one guide.
Even existing tank equipment can be easily equipped with the functions of residual quantity detection and water intrusion detection. Further, even with a configuration in which a detector for digitally displaying the remaining amount detection is provided to read the raising / lowering operation of the float, the floating / sinking operation of the float is stabilized, so that the accuracy of the remaining amount detection can be improved.

Further, since it is not necessary to provide a flange or the like for restricting the movement in the width direction on the guide shaft or the like for guiding the float tape to the detection mechanism side, the resistance to the float tape is reduced and the fluctuation of the liquid level is surely detected on the detection mechanism side. It is possible to further improve the detection accuracy by transmitting to the.

Further, in the case where the detector is provided with a digital display system, the operation of the float is stable and the liquid level can be accurately detected by this, and in addition, the numerical value is displayed, so that the inside of the tank is further raised. You will be able to grasp with accuracy.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a main part of an underground tank provided with a remaining amount and water detection structure of the present invention.

FIG. 2 is a cross-sectional view showing the internal structure of the detector.

FIG. 3 is a main part of a structure in which a float is connected to a guide, (a) of which is an exploded perspective view of a guide and a hook;
(B) of the same figure is a front view of the main part for showing that the axis of the float can be set parallel to the guide.

FIG. 4 is a front view of the main part when the float is in a posture orthogonal to the guide.

FIG. 5 is a vertical cross-sectional view of a main part showing a water detection float portion.

FIG. 6 is a vertical cross-sectional view of a main part showing an example of a conventional remaining amount detecting structure.

7 is a cross-sectional view showing the internal structure of the detector in the example of FIG.

[Explanation of symbols]

 1: Tank main body 1a: Suction tube 2: Detector 2a: Tape drum 2b, 2c: Guide shaft 2d: Potentiometer 2e: Rotating shaft 2f: Gear train 3: Float 3a: Float tape 4: Weight 4a: Weight tape 5: Guide 5a: Contact element 6: Hook 7: Water detection float 7a: Magnet

Claims (2)

[Claims] 1. A float, which responds to a liquid level inside a tank main body, and a detector capable of calculating rotation amount of the float by detecting rotation of a drum connected to a float tape connected to the float. In an underground tank, a water detection float which is provided inside the tank body, connects the float to the guide so as to be able to move up and down, and is externally inserted below the float so as to be able to move up and down by the guide and has a built-in magnet And a structure for detecting a liquid level and water in a storage tank such as an underground tank, in which the guide is provided with a contact element operable by the magnet at a position corresponding to the allowable water intrusion water level in the tank. 2. The structure for detecting the liquid level and water in a storage tank such as an underground tank according to claim 1, wherein the detector comprises a system for AD-converting a liquid level detection signal and digitally displaying the remaining amount in the tank. .