JP2001174317A - Liquid leakage detecting sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid leakage detecting sensor reliably detecting a liquid with the specific gravity smaller than that of water with a simple structure and capable of reducing the cost. SOLUTION: This liquid leakage detecting sensor is provided with a main float 1 with the specific gravity smaller than that of water and larger than that of the liquid to be detected, a sub-float 2 with the specific gravity smaller than that of the liquid to be detected and submersibly fitted to the main float 1, and a means converting the floating of the sub-float 2 into an electric signal. The sub-float 2 is installed vertically movably against a guide pipe 3 provided on the main float 1, a magnet 5 is installed on the sub-float 2, and the magnetic sensor such as a reed switch 6 operated by the approach of the magnet 5 is installed on the guide pipe 3. The liquid such as oil with the specific gravity smaller than that of water and accumulated in a drainage pit or the like is detected reliably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid leak detection sensor in a liquid reservoir such as a drain pit installed around an oil storage facility.

[0002]

2. Description of the Related Art An oil leak detection sensor is installed at a drain pit in a tank oil dike or a drain pit near a plant or a pump yard to constantly monitor oil leaks day and night. However, since rainwater and the like accumulate in the drain pit, simply monitoring the level of the liquid in the pit does not mean that an oil leak has been detected.

In order to cope with such a situation, a float type sensor has been provided. The structure is shown in FIG. In the figure, 11 is a float body which is lighter than the specific gravity of water, 1
2 is a detection probe, 13 is a microswitch, 14 is an auxiliary probe, and 15 is a measurement signal transmission cable. The detection principle is to detect the difference between the capacitance of water and oil.
2 is to detect.

The float body 11 floating on the water surface such as a drain pit normally measures the capacitance of water by a detection probe 12. When the oil layer is formed on the water surface, the float main body 11 rises to the oil surface, and the detection probe 12 is relatively pulled out of the water, and the capacitance being measured decreases. This change is transmitted as a current signal to a remote transducer via a cable, which activates a relay to detect an oil leak.

When the drain pit is depleted of water, the auxiliary probe 14 protruding from the lower end of the float main body 11 is pushed up, the micro switch 13 is operated, and the output of the detection probe 12 is short-circuited. Electrically, this short circuit provides the same signal as measuring the capacitance of water. If water enters the pit in this state, the alarm is not issued because the capacitance of the water is measured even if the short circuit is broken.
When oil enters, the capacitance being measured when the short circuit breaks off is greatly reduced and an alarm is issued.

[0006]

However, the above-mentioned conventional float-type sensor has a complicated structure and a complicated electric circuit, so that a considerable cost is required and a product price is very high. In addition, the electrostatic capacitance type is liable to malfunction if dust or the like adheres to the detection portion, and has poor reliability. Therefore, the problem to be solved by the present invention is to reliably detect a liquid having a lighter specific gravity than water with a simple structure,
Another object of the present invention is to provide a liquid leakage detection sensor that can reduce costs.

[0007]

In order to solve the above-mentioned problems, a liquid leak detection sensor according to the present invention comprises a main float having a specific gravity smaller than the specific gravity of water and larger than the specific gravity of the liquid to be detected. To be able to float up and down,
A sub-float having a specific gravity smaller than the specific gravity of the liquid to be detected, and a means for converting the floating of the sub-float into an electric signal. In this liquid leak detection sensor, a sub-float is installed so as to be able to ascend and descend with respect to a guide pipe provided on a main float, a magnet is provided on the sub-float, and a reed switch and other magnetic sensors are operated by the proximity of the magnet to the guide pipe. Can be provided.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below based on embodiments shown in the drawings. 1A and 1B show an embodiment of the present invention, in which FIG. 1A is a sectional view, FIG. 1B is a plan view, and FIG. 1C is a sectional view of a sensor section.

In FIG. 1, reference numeral 1 denotes a main float, which is set to a specific gravity smaller than the specific gravity of water but larger than the specific gravity of oil, for example, 0.9. A guide ring 7 is provided on a side portion of the main float 1, and is configured to be able to float and descend along a column 10 provided in a drainage pit or the like. A guide pipe 3 is provided at the center of the main float 1 and has a specific gravity of oil (0.85
油 0.75), for example, an oil float 2 having a specific gravity of 0.5 is attached to be able to move up and down. Oil float 2
A magnet 5 is fixed in the inside, and a reed switch 6 is mounted in the guide pipe 3. A signal for opening and closing the reed switch 6 is transmitted to a remote control panel or the like via the cable 4.

The operation of the embodiment of the present invention will be described with reference to FIG. FIG. 2A shows a case where only water accumulates in the pit P. When the water W accumulates in the pit P, the main float 1 rises. At this time, since the level of the oil float 2 is higher than the level of the main float 1, no alarm is issued.

FIG. 2B shows a case where the oil O accumulates on the water W. When the oil O enters the pit P, the oil O accumulates on the water W and accumulates in a certain amount. Then, the oil float 2 rises, and the reed switch 6 incorporated in the guide pipe 3 is turned on by the influence of the magnetic field of the magnet 5 in the oil float 2, and a signal is generated.

FIG. 2 (c) shows a case where only oil accumulates in the pit P. In this case, the main float 1 does not float at all, and when a certain amount of oil accumulates, the oil float 2 rises and the guide pipe 3 The reed switch 6 incorporated therein is turned on, and a signal is emitted.

Although a reed switch having a simple structure is used as the means operated by the magnetic field of the magnet 5, a semiconductor magnetic sensor such as a magnet diode or a Hall element may be used. In the above, the case of water and oil having different specific gravities has been described. However, the case of two kinds of liquids having different specific gravities that are not mixed with each other can be similarly detected.

[0014]

As described above, according to the present invention, the following effects can be obtained. (1) With a simple structure, it is possible to reliably detect a liquid having a specific gravity lower than that of water. (2) Since the cost is reduced in both the structure and the electric circuit, it can be provided at low cost. (3) There is no effect on operation due to the attachment of dust and the like, and the structure is simple, so there are few failures and the reliability is greatly improved.

[Brief description of the drawings]

1 shows an embodiment of the present invention, in which (a) is a sectional view, (b) is a plan view, and (c) is a sectional view of a sensor section.

FIG. 2 is an explanatory diagram showing an operation of the embodiment of the present invention.

FIG. 3 is a partially cutaway front view showing an example of a conventional float-type sensor.

[Explanation of symbols]

1 main float, 2 oil float (sub float), 3
Guide pipe, 4 cables, 5 magnets, 6 reed switches, 7 guide rings, 10 posts, P pits, W water, O oil, 11 float body, 12 detection probe, 13 micro switch, 14 auxiliary probe, 15 measurement signal transmission cable

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[Procedure amendment]

[Submission date] January 16, 2001 (2001.1.1)
6)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

[0007]

According to the present invention, a specific gravity smaller than the specific gravity of water and larger than the specific gravity of the liquid to be detected is provided.
Comprising a main float, an auxiliary float having a smaller specific gravity than the specific gravity of the liquid to be tested knowledge with, the main float
Ring-shaped, with a guide ring on its side, for measurement
If the liquid to be contained contains water, provide support for the facility that contains the liquid.
The sub-float is freely movable up and down along the pillar,
Along the guide pipe provided in the center of the main float
It is mounted so that it can move up and down,
Is provided with a magnet, and the guide pipe
Is provided with a magnetic sensor and is close to the magnet.
Liquid leakage that converts the float of the sub-float into an electrical signal by contact
It is a leak detection sensor .

Claims (3)

[Claims] 1. A main float having a specific gravity smaller than the specific gravity of water and larger than the specific gravity of a liquid to be detected, and a sub float having a specific gravity smaller than the specific gravity of the liquid to be detected attached to the main float so as to float. And a means for converting the floating of the sub-float into an electric signal. 2. A sub-float is installed so as to be able to move up and down with respect to a guide pipe provided on a main float, a magnet is installed on the sub-float, and a magnetic sensor is operated on the guide pipe by the proximity of the magnet. The liquid leak detection sensor according to claim 1, wherein 3. The liquid leakage detection sensor according to claim 2, wherein the magnetic sensor is a reed switch.