JP4037838B2 - Tank rehabilitation method with oil leakage warning function and rehabilitation tank with oil leakage warning function - Google Patents

Description

  The present invention relates to a method for rehabilitating a double-shell tank having an oil leakage warning function and its structure in rehabilitation of a fuel tank embedded in a gas station or the like, and includes a tank body and rehabilitation materials such as an FRP sheet. In the meantime, an oil leakage sensor is installed to have a function of promptly alarming oil leakage due to a defect of the rehabilitation material.

Underground fuel tanks buried in gasoline stations and the like are made of iron plates, but after more than 20 years of construction, there is a risk that internal gasoline, light oil, etc. will leak due to internal corrosion, electric corrosion, etc. come. If this leakage occurs, soil contamination will occur, which will be a major social problem such as environmental contamination, and will require enormous costs for its treatment.
Therefore, when drilling holes in the soil outside the four corners of the above-mentioned underground fuel tank and periodically putting a piece of cloth such as a rag into the back of each hole, and lifting these pieces of cloth, In addition, it is confirmed whether or not the oil leaked into the soil is attached, and thereby it is detected whether or not the oil inside the tank is leaking into the soil.
However, in this method of detecting oil leakage from soil contamination around the underground fuel tank, in addition to the loss of fuel such as gasoline, it takes enormous effort and cost to clean up the soil, and environmental pollution It is unacceptable from the aspect of.
Therefore, in order to prevent such soil contamination, after the tank is used for a certain period of time, the tank is inspected for openness, and an iron plate having a thickness of 3.2 mm or less cannot be used continuously by law. When the thickness of the iron plate of the tank is 3.2 mm or more, the tank is repaired by lining the inner surface of the tank with a regenerated material made of FRP sheet with a thickness of 2 to 3 mm to extend the life of the tank. Yes.
JP2001-348089

  However, if a problem occurs in the lining of the rehabilitated material and the fuel leaks between the rehabilitated material and the inner surface of the tank, deterioration of the tank inner surface is promoted by water slightly contained in the fuel. Eventually, fuel such as oil will leak into the ground outside the tank. However, at present, there is no way to check whether the rehabilitation material is properly lined or whether the rehabilitation material has cracked due to aging.

  Therefore, in order to prevent such soil contamination, the present invention performs an open inspection of the tank, repairs the tank wall by lining the inner surface with FRP or the like as a rehabilitation material, and leaks oil from the rehabilitation material. The present invention is to provide a double shell tank rehabilitation method and a structure thereof having a function of detecting and alarming to solve the above problems.

The invention according to claim 1, in facilities to tanks retreading method rehabilitating material on the inner surface of the tank, performs overhaul inspection of the tank to wash the inside, repellent to some or all of the inner surface of the tank after having been subjected to primary treatment An optical fiber sensor is provided in contact with a part of this water-repellent oil-absorbing fiber, and a line with one end connected to this sensor is placed over the inner surface of the tank so that the line is led out of the tank. When light emitted from one end of the optical fiber sensor is received at the other end and oil adheres to the optical fiber sensor, an optical transmission loss occurs. The optical transmission loss is converted into an electrical signal by a converter, and the electrical a configuration in which signals are alarm oil alarm device leakage when a predetermined value or more, the water-repellent oil absorption fibers, from the top of the optical fiber sensor and the line, characterized in that subjected to rehabilitating material on the inner peripheral surface of the tank, Oil leakage alarm function It was a gas tank rehabilitation method. According to a second aspect of the present invention, in the first aspect of the invention, the oil leakage alarm device is provided with a plurality of optical fiber sensors, and these optical fiber sensors are arranged at a plurality of locations on the inner periphery of one tank or a plurality of optical fiber sensors. of characterized in that arranged on the inner periphery of the tank, and the tank rehabilitation method-out with oil leakage alarm function.

The invention of claim 3 is the further Namata link the rehabilitating material is applied to the inner surface of the tank, overhaul inspection of the tank, internal cleaning, and, after the primary treatment, stretched on a part or the whole of the inner surface of the tank An optical fiber sensor is in contact with a part of the water-repellent oil-absorbing fiber, and a line having one end connected to the sensor is led from the inner surface of the tank to the outside of the tank and connected to the oil leakage alarm device. When light emitted from one end of the sensor is received at the other end and oil adheres to the optical fiber sensor, an optical transmission loss occurs, and this optical transmission loss is converted into an electrical signal by a converter. In the above case, the oil leakage warning device is configured to warn, and the optical fiber sensor comprises a clothing layer covering the core wire and a protective tube covering them, and a plurality of through holes are provided on the outer periphery of the protective tube. Protection The core is exposed at stripped part of the clothing layers of inner, water repellent oil absorption fibers, from the top of the optical fiber sensor and the line, characterized in that the rehabilitation material is applied to the inner peripheral surface of the tank , was further Namata link with oil leakage alarm function. According to a fourth aspect of the present invention, in the third aspect of the present invention, the oil leakage alarm device is provided with a plurality of optical fiber sensors, and these optical fiber sensors are arranged at a plurality of locations on the inner periphery of one tank or a plurality of optical fiber sensors. A rehabilitation tank with an oil leakage warning function, characterized in that it was placed on the inner circumference of the tank.

According to the inventions of claims 1 and 3 , when the lining of the rehabilitation material applied to the inner surface of the tank is not properly performed or when the rehabilitation material has cracked due to aging, the internal fuel is When leaking, the water-repellent oil-absorbing fiber provided between the inner surface of the tank and the rehabilitation material absorbs this quickly and leads to the sensor, and the sensor detects the oil leak early and alerts it. Therefore, precautions can be taken easily and reliably before liquid combustibles such as oil leak outside the tank, and soil contamination due to corrosion of the tank inner surface is not caused. In addition, since the sensor is an optical fiber sensor, oil leakage is attached to the optical fiber sensor, thereby causing a large optical transmission loss, which is converted into an electrical signal and an alarm is generated. The detection area is large and the leak detection function is excellent. Further, according to the invention of claim 2 and 4, since it is possible to a large number portion of the inner surface of one tank providing an optical fiber sensor, it is possible to quickly detect the leakage oil from the various points of the tank. Further, since it detects a leakage oil of a plurality of tanks in one detection alarm device that provided the respective optical fiber sensors on the inner surface of the plurality of tanks, the efficiency can be achieved.

  In the double shell tank refurbishment structure that applies the rehabilitation material to the inner surface of the tank, the tank is inspected for opening, the inside is cleaned, and the water repellent oil absorbing fiber is applied to a part or all of the inner surface of the tank after the primary treatment, An oil leakage sensor consisting of an optical fiber sensor is provided in contact with a part of the water-repellent oil-absorbing fiber, and an optical fiber having one end connected to the sensor is placed on the inner surface of the tank, and the optical fiber is led out of the tank. Then, connect to the oil leakage alarm device, apply rehabilitation material to the inner peripheral surface of the tank from above the water-repellent oil-absorbing fiber, oil leakage sensor and optical fiber, and oil will flow between the regenerated material and the tank inner surface. When it leaks, it is absorbed by the water-repellent oil-absorbing fiber, and oil adheres to the oil leak sensor, thereby causing a large optical transmission loss, which is converted into an electric signal and an alarm is issued.

1 and 2 are a sectional front view and a sectional side view of an existing underground tank showing the configuration of the present invention. As in the conventional tank, the iron tank 1 is provided with an inlet 2 for putting liquid combustible material into the tank 1, an oil feed pipe 3 for taking out liquid combustible material from the inside, a vent pipe 4, and a metering port 5. It has been.
When the existing tank 1 is rehabilitated, the remaining fuel and sludge are discharged, the inspection manhole 6 is opened, the inside of the tank 1 is cleaned, and the thickness of the tank body is confirmed as in the prior art.
In order to add an oil leakage detection function, after performing a primer treatment after inspection and cleaning of the inner surface of the tank 1, water-repellent oil absorbing fibers are attached to appropriate portions of the inner surface of the tank 1 (not shown), and an oil leakage sensor The plastic fiber sensor 7 is inserted from the vent pipe 4 of the tank 1 and is laid so as to contact the water-repellent oil-absorbing fiber around the lower portion of the tank 1, and the end portion is folded back so as to form a loop. The trachea 4 is led out of the tank 1. Thereafter, a UV curable FRP sheet 8 as a rehabilitation material is pasted on the entire inner surface of the tank 1 to form a double shell.

The plastic fiber sensor 7 is composed of a loop-shaped optical fiber sensor, and transmits near-infrared light emitted from a light emitting element (light emitting diode) provided at one end through the optical fiber sensor, and a light receiving element (photograph) as a light receiving unit at the other end. When the oil is attached to the plastic fiber sensor 7, an optical transmission loss (difference in the optical signal level between the light emitting part and the light receiving part) occurs, and this optical transmission loss is converted into an electrical signal by a converter. When the value of the electric signal is converted to an alarm set value or more, an alarm is given by the oil leakage alarm device.
The amount of light that passes through this optical fiber sensor and reaches the light receiving element varies depending on the length of the optical fiber sensor and the polished state of the end face, and in normal conditions (no oil is attached) The drive current of the light emitting element is corrected so as to keep the amount of light reaching the constant.
The optical signal received by the light receiving element is converted into a voltage signal by the converter, and the arithmetic element in the monitor reads the voltage signal at every sampling time of a predetermined interval. The monitor operates the drive voltage of the light receiving element so as to always maintain a constant set value while the alarm value set in advance is not reached.

  This oil leakage warning system (trade name “Oil Leak Monitor” manufactured by IHI Escube Co., Ltd.) draws the plastic fiber sensor 7 into the inside of the tank 1 and leads both ends out of the vent pipe 4 of the tank 1. As shown in FIG. 3, these are connected to a converter 9, and an electric signal converted by the converter 9 is sent to an oil leakage alarm device 10 including a monitoring device via a cable 10a. Since the oil leak detectors such as the plastic fiber sensor 7 and the converter 9 are installed in a hazardous area, they are composed of intrinsically safe equipment. The plastic fiber sensor 7 can be used with a length of about 30 m at the longest. Further, since the converter 9 and the monitor 10 are connected by a shielded control cable, the oil leakage alarm device 10 including the monitor is provided. Can be installed in a non-hazardous area.

As shown in FIG. 4, the specific configuration of the plastic fiber sensor 7 is such that the outer periphery is covered with a coating layer 11 in order to eliminate the loss of transmitting near-infrared light emitted from the light-emitting diode to the photodiode as the light-receiving unit. A protective tube 12 made of a stainless steel tube, a Teflon (registered trademark) tube, or the like is coated thereon, and a large number of through holes 13 are formed in the outer periphery of the protective tube 12, and a part of the coating layer 11 in the protective tube 12 is formed. Is peeled off to expose the core wire 14, and oil leakage is detected at the core wire 14 portion.
Further, the core wire 14 from which the covering layer 11 of the plastic fiber sensor 7 in FIG. 4 is peeled is about 1 m. However, as shown in FIG. Alternatively, by providing 10 at intervals, the detection area for oil leakage can be expanded.

  In actual operation, as shown in Fig. 6A and Fig. B, if oil leakage occurs due to poor construction or deterioration over time of rehabilitation materials made of FRP sheets, the above protection is provided. A plurality of plastic fiber sensors 7 contained in a pipe 12 (not shown) may be provided on the inner periphery of one tank 1. Further, although not shown, the “oil leak monitor” (trade name) includes a pair of a sensor, a converter, and an oil leakage alarm device. It may be provided on the inner periphery of the tank 1. In any case, as shown in FIG. 7, the plurality of plastic fiber sensors 7 are collected in the converter 9, and the light direction of one light emitting element 15 is changed as shown in FIGS. 8A and 8B. Then, the light is converted by a rotating mirror 16 and passed through one of a plurality of plastic fiber sensors 7 in the outward path, and the rotating mirror 17 is rotated from one of the plastic fiber sensors 7 in the backward path to be received by one light receiving element 18. It can also be set as the structure to make. Thereby, the number of the light emitting elements 15 and the light receiving elements 18 can be reduced, and the converter 9 can be reduced in size and weight.

Further, as described above, after the primer treatment is performed after the inner surface of the tank 1 is inspected and cleaned, the water-repellent oil-absorbing fiber is attached to an appropriate portion of the inner surface of the tank 1, and the water-repellent oil-absorbing fiber 19 is a polypropylene fiber. (Trade name “Tafnel” manufactured by Mitsui Chemicals Co., Ltd.), as shown in FIG. 9, a strip having a width of about 10 cm is stretched on the side surface and bottom surface of the tank 1 with a plurality of intervals in the longitudinal direction. A plurality of the tanks 1 are stretched at annular intervals along the inner peripheral surface of the tank 1. Then, the plastic fiber sensor 7 is brought into contact with the part of the water-repellent oil-absorbing fibers 19 so as to wrap the plastic fiber sensor 7, and the plastic fiber sensor 7 is wound on the inner surface of the tank 1. As a result, the water-repellent oil-absorbing fiber 19 quickly absorbs the oil leakage from the tank 1 and induces oil leakage to the lower portion of the tank 1 as time elapses, and the oil leakage easily adheres to the core wire 14 of the plastic fiber sensor 7. The structure is as follows. For this purpose, as shown in FIG. 10, a protective tube 12 containing the plastic fiber sensor 7 is meandered at the bottom of the tank 1 where oil can be easily stored, and the numerous transparent tubes 12 are disposed in the protective tube 12 at the meandering location. The hole 13 can be opened to facilitate detection of oil leakage.
Thereafter, the UV curable FRP sheet 8 is used as a rehabilitation material, and is adhered to the inner peripheral surface of the tank 1 from above the water-repellent oil-absorbing fiber 19 and the plastic fiber sensor 7. As shown in FIG. 11, the ultraviolet curable FRP sheet 8 has a first belt-like sheet 8a stretched between the inner peripheries of the tank 1 with a space therebetween, and a second belt-like sheet 8b between these sheets 8a. The first and second strips 8a and 8b are stretched so that their edges overlap each other.

  In the above embodiment, the oil leakage sensor uses an optical fiber. However, the present invention is not limited to this, and a sensor of a type or configuration such as a capacitance type, an electric resistance type, or a reflection type can also be used. However, when an optical fiber is used, the detection area can be widened compared to other types of sensors, and since it is a flexible linear body, it can be handled in an optimum shape for the detection target, and early. Excellent leakage monitoring function. In addition to the plastic fiber sensor of the above embodiment, a quartz fiber sensor can be used as the optical fiber sensor. Further, in the case of the above optical fiber sensor, it is easy to detect disconnection, and those in a protective tube such as a stainless steel tube can be easily replaced when disconnected. Moreover, although the ultraviolet curable FRP sheet was used as the rehabilitation material in the above-described embodiment, other rehabilitation materials may be used, and the rehabilitation material may be applied by coating instead of attaching the sheet. Moreover, in the said Example, although the fuel tank embed | buried underground was used, this invention can be used not only for an underground burial tank but for a ground tank.

  In addition, the present invention can provide the oil leakage warning function similar to the above in the double shell tank forming method in which FRP is applied to the outer surface of the tank installed on the ground or in the tank. Although not shown, the water-repellent oil-absorbing fiber is stretched on a part or all of the outer surface of the tank, and the oil-leak sensor is provided in contact with a part of the water-repellent oil-absorbing fiber, and one end is connected to the sensor. Route the line over the outer surface of the tank and lead the line to the outside of the tank, where it is connected to the oil leakage alarm device, and the FRP is placed on the outer peripheral surface of the tank from above the water-repellent oil absorbing fiber, oil leakage sensor and line. The method for forming a double shell tank with an oil leakage warning function or a double shell tank formed by this method can be used.

It is a section front view showing a schematic structure of a tank of this invention. It is a section side view showing the outline composition of the tank of this invention. It is an explanation perspective view showing the composition of the oil leak warning system of this invention. It is a description side view which shows the principle structure of the oil leak sensor of this invention. It is an explanatory side view showing other composition of the oil leakage sensor of this invention. FIGS. A and B are schematic perspective views showing the arrangement of the oil leakage sensor of the present invention in the tank. It is a description perspective view which shows the other application structure of the oil leak warning system of this invention. FIGS. A and B are explanatory configuration diagrams showing the arrangement of a plurality of oil leakage sensors using a rotary movable mirror in the oil leakage alarm system of the present invention. It is a description perspective view which shows the sticking structure of the water repellent oil absorption fiber to the tank inner surface of this invention. FIG. 3 is an explanatory perspective view in which a protective tube for an oil leakage sensor is meandered on the bottom surface of the tank according to the present invention. It is a description perspective view which shows the sticking procedure of the ultraviolet curable FRP sheet to the tank inner surface of this invention.

Explanation of symbols

1 tank
2 Inlet 3 Oil supply pipe
DESCRIPTION OF SYMBOLS 4 Vent pipe 5 Metering port 6 Manhole for inspection 7 Plastic fiber sensor 8 UV curable FRP sheet 9 Converter 10 Oil leak alarm device 10a Cable 11 Cover layer 12 Protective tube 13 Through hole 14 Core wire 15 Light emitting element 16 Rotating mirror 17 Rotating mirror 18 Light-receiving element 19 Water-repellent oil-absorbing fiber

Claims (4)

In facilities to tanks retreading method rehabilitating material on the inner surface of the tank,
Inspect the tank for openness, clean the inside, apply a water-repellent oil absorbing fiber to part or all of the inner surface of the tank after the primary treatment, and contact the optical fiber sensor with a part of this water-repellent oil absorbing fiber. A line having one end connected to the sensor is placed over the inner surface of the tank, the line is led out of the tank, light emitted from one end of the optical fiber sensor is received at the other end, and the optical fiber sensor oil is a light transmission loss in the case of contact, the optical transmission loss is converted into an electrical signal by the transducer, and a configuration in which the electrical signal is an alarm in the oil alarm device leakage when a predetermined value or more, the water-repellent oil fibers, from the top of the optical fiber sensor and the line, characterized in that subjected to rehabilitating material on the inner peripheral surface of the tank, tank rehabilitation method-out with oil leakage alarm function. A plurality of optical fiber sensor in the leaked oil alarm device, characterized in that these optical fiber sensor to one of the inner circumference of the plurality of positions of the tank, or placed on the inner periphery of the plurality of tanks, the billing tank rehabilitation way-out oil leakage with alarm functions described in claim 1. In a further Namata link the rehabilitating material is applied to the inner surface of the tank,
After tank open inspection, internal cleaning, and primary treatment, an optical fiber sensor is in contact with a part of the water-repellent oil-absorbing fiber stretched on part or all of the tank inner surface, and one end is connected to this sensor. When the line is led from the inner surface of the tank to the outside of the tank and connected to the oil leakage alarm device, the light emitted from one end of the optical fiber sensor is received at the other end, and the oil adheres to the optical fiber sensor It becomes a light transmission loss, this light transmission loss is converted into an electric signal by a converter, and when the electric signal is a certain value or more, the above oil leakage alarm device warns.
The optical fiber sensor comprises a clothing layer covering the core wire and a protective tube covering them,
A number of through holes are provided on the outer periphery of the protective tube,
The core wire is exposed by peeling a part of the clothing layer in the protective tube,
Water repellent oil absorption fibers, from the top of the optical fiber sensor and the line, characterized in that the rehabilitating material on the inner peripheral surface of the tank is subjected, further Namata linked with oil leakage alarm function. A plurality of optical fiber sensor in the leaked oil alarm device, characterized in that these optical fiber sensor to one of the inner circumference of the plurality of positions of the tank, or placed on the inner periphery of the plurality of tanks, the billing Item 4. Rehabilitation tank with oil leakage warning function according to item 3.

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