JP3019252B2 - Leak detection device for gas station underground tanks - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leak detecting device for a gas station underground tank for detecting oil or ground water leaking from an inner shell or an outer shell of a gas station underground tank.

[0002]

2. Description of the Related Art In order to detect oil leakage from a gas station underground tank, a leak detection device is provided in the tank.

FIG. 4 is a schematic diagram of a conventional leak detection system for gasoline station underground tanks, and FIG. 5 is an overall view of a conventional gasoline station underground tank leak detection device.

The underground tank comprises a steel tank inner shell 1 and a tank outer shell 2 made of FRP coated on the outer surface of the tank inner shell 1, and has leaked between the tank inner shell 1 and the tank outer shell 2. An oil detection layer 3 is formed.

[0005] A detection pipe 4 is provided in the tank so as to penetrate from the upper part to the lower part of the tank. The lower end of the detection tube 4 is closed with a perforated steel plate 6 to allow the detection tube 4 and the detection layer 3 to communicate with each other.

FIG. 3 is a sectional view of the float switch.

[0007] The leak detection device is a terminal box 7 at the top of the device.
The detection unit 5 is provided at the lower end of the guide pipe 8 connected to the sensor. The detection unit 5 is fixed to the lower end of the guide pipe 8 and has a switch rod 11 in which a reed switch 10 is disposed.
The float switch includes a float 13 having a built-in permanent magnet 12 that slides around the switch rod 11.

An operation check plate 14 is provided below the float 13 as a float pulling body so as to be slidable around the switch rod 11. The operation check plate 14 is composed of a plurality of wires 15 locked on the periphery thereof. It is hung down on the protection plate 16 placed on the upper part of the switch rod 11. In addition, the operation check plate 14 is locked with one end of an operation check wire 17 as a float pulling jig so as to lift the operation check plate 14 upward.
The other end of 7 is fixed to a plug 18 provided on the upper part of the detection tube 4.

The detection operation of the leak detection device will be described.

For example, if the tank inner shell 1 is damaged and oil leaks, the oil reaches the lower part of the tank through the detection layer 3 between the tank inner shell 1 and the tank outer shell 2 and is perforated at the lower part of the tank. It enters the detection tube 4 through the steel plate 6. When the oil accumulates in the detection tube 4, the float 13 rises, and when it reaches the position of the reed switch 10 set to the leak alarm level of the switch rod 11, the reed switch 10 is set by the permanent magnet 12 built in the float 13. Is turned on, the ON signal is sent to the terminal box 7, and further sent to the indoor monitor 19 to notify the abnormality.

When the tank outer shell 1 is damaged, groundwater flows into the detecting layer 3 between the tank inner shell 1 and the tank outer shell 2, and the float 13 is moved in the same manner as in the case of oil leakage described above. As a result, the reed switch 10 is turned on, and the monitor 9 notifies an abnormality by an ON signal.

As described above, the leak detecting device is required to always function normally in order to quickly detect the leak from the underground tank and to ensure safety. Therefore, the operation of the float switch is periodically checked. ing.

[0013] The operation of the leak detection device can be checked by opening the plug and pulling up the operation check wire by raising the operation check plate and, at the same time, raising the float and operating the reed switch normally. Check.

[0014]

During the checking operation, the detecting portion is tilted because it is supported by the cantilever by the operation checking wire, and when the detecting portion is lowered while being tilted by the operation checking wire, the detecting portion is turned off. There is a risk of malfunction due to overturning or tilting. In some cases, the operation confirmation wire is pulled too much and the wire is cut.

Accordingly, the present invention provides a checking device for a gasoline station underground tank leak detecting device in which the detecting section does not fall down due to the checking operation of the leak detecting device.

[0016]

According to the present invention, there is provided a leak detecting device for a gas station underground tank, wherein a detecting portion is arranged at a lower portion in a detecting pipe of the gas station underground tank, and the detecting portion and the terminal box are connected by a cable. A leak detection device for a gas station underground tank in which an operation check wire is connected to a detection unit, wherein the detection unit includes a switch rod having a reed switch disposed therein, and a float with a built-in permanent magnet sliding on the switch rod. The float pull-up body that raises the float is provided movably with respect to the switch rod, and the float pull-up body jig is fixed to the float pull-up body, and the detection unit is located just above the center position of the detection unit. The jig is provided with a float pulling body jig so as to lift the jig.

[0017]

1 is an overall view of a leak detecting device for a gas station underground tank according to the present invention, and FIG. 2 is a front view of a detecting portion of the leak detecting device according to the present invention.

The structures of the underground tank and the detection tube are as described in the prior art. In the drawings, the same members are denoted by the same reference numerals and the description thereof will be omitted. The terminal box 7 has a flanged pipe 19 above the flange of the detection tube 4.
On top of

The detection unit 5 is disposed below the detection tube 4 and
The terminal box 7 and the detection unit 7 are connected by a cable 20.

The detection unit 5 is housed in a cylindrical body 21 made of resin, and has a switch rod 11 in which a reed switch is disposed inside and a permanent magnet built-in which slides around the switch rod 11 as in the prior art. And a float switch composed of a float 13 of FIG.

Around the float 13, as a float pulling body, a perforated bottom through which the switch rod 11 passes is located below the float, and an operation confirmation tube 22 having a wall surrounding the float formed above the perforated bottom. Is provided movably with respect to the switch rod 11.

The operation checking cylinder 22 which is a float pulling body
Has a wire 1 for operation confirmation as a float pulling jig
7 are fixed to both ends of the diameter of the operation confirmation tube 22, respectively, and the respective operation confirmation wires 17 are drawn out through long holes provided on both sides of the cylindrical main body 21 so as to face both ends of the diameter.

Protective lid 2 fixed on top of cylindrical body 21
3 is provided with a hole for passing a cable, a hole for fixing to a cylindrical main body, and a hole for preventing movement of an operation confirmation wire in the center.

The operation confirming wire 17 is connected at the upper portion of the protective cover 23 to form a loop, and one end of the wire 17 is connected so as to lift the detecting portion 5 just above the center position of the detecting portion.
The other end is fixed to a plug provided in the terminal box.

The cable 20 is fixed by a cable fastener 24 on a protective lid and a cover nut 26 arranged on a rib 25 in the middle of the tubular main body 21.

In the above configuration, when the inner shell 1 of the tank is damaged and oil leaks, or when the outer shell of the tank is damaged and groundwater flows in, the oil or groundwater is discharged as described in the aforementioned conventional example. It reaches the lower part of the tank through the detecting layer 3 between the tank inner shell 1 and the tank outer shell 2, enters the detecting pipe 4 through the perforated steel plate 6 at the lower part of the tank, and accumulates oil or groundwater in the detecting pipe 4. Then, when the float 13 rises and reaches the position of the reed switch 10 set to the leak alarm level of the switch rod 11, the reed switch 10 is turned on by the permanent magnet 12 built in the float 13 and the ON signal is output to the terminal. Sent to box 7 and indoor monitor 9
To be notified of abnormalities.

The operation of the leak detection device of the present invention can be checked by pulling up the plug 18 to which the operation checking wire 17 is fixed, whereby the operation check tube 22 rises, the float 13 rises, and the reed switch 10 moves Check if it works properly.

[0028]

【The invention's effect】

(1) In the present invention, since the suspending position of the operation confirmation wire is provided immediately above the detecting unit, the detecting unit can be suspended vertically, and the falling and tilting of the detecting unit can be prevented.
As a result, malfunction can be eliminated.

(2) In the present invention, since the detection unit itself is lifted even if the operation confirmation wire is pulled too much, there is no possibility that the wire is cut or the detection unit is damaged.

(3) It has a simple mechanical structure and can be manufactured at low cost.

(4) Since it has a simple structure, it has durability.

[Brief description of the drawings]

FIG. 1 is an overall view of a leak detection device for a gas station underground tank according to the present invention.

FIG. 2 is a front view of a detection unit of the leakage detection device according to the present invention.

FIG. 3 is a sectional view of a float switch.

FIG. 4 is a schematic view of a conventional leak detection system for gas station underground tanks.

FIG. 5 is an overall view of a conventional leak detection device for a gas station underground tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tank inner shell 2 Tank outer shell 3 Detecting layer 4 Detecting tube 5 Detecting part 6 Perforated steel plate 7 Terminal box 8 Guide pipe 9 Monitor 10 Reed switch 11 Switch rod 12 Permanent magnet 13 Float 14 Operation check plate (Float lifting body) 15 Wire 16 Protective plate 17 Operation confirmation wire (float lifting body jig) 18 Plug 19 Flanged pipe 20 Cable 21 Tubular body 22 Operation confirmation cylinder (Float lifting body) 23 Protective lid 24 Cable fastener 25 Rib 26 Cover nut

Claims (1)

(57) [Claims] 1. A gas station underground tank in which a detection unit is arranged in a lower part of a detection pipe of a gas station underground tank, the detection unit and a terminal box are connected by a cable, and a float lifting jig is connected to the detection unit. Leak detector, wherein the detection unit comprises a float switch including a switch rod having a reed switch disposed therein and a float with a built-in permanent magnet that slides the switch rod. It is provided movably with respect to the switch rod, and the float lifting body jig is fixed to the float lifting body, and the float lifting body jig is provided so as to lift the detection unit just above the center position of the detection unit Leak detection device for gas station underground tanks.