Double-pipe structure

Abstract

To provide a piping system for supplying fuels such as gasoline, light oil, and petroleum, a piping system for supplying organic solvents such as toluene, alcohol, xylene, and ketone, and a piping system for supplying liquids such as bases including sodium hydroxide, paints, colloids including milk, and water.SOLUTION: The present invention relates to a double-pipe structure for detecting leakage of liquid flowing in such piping. In particular, an oil leakage alarm device includes an oil leakage detection circuit for detecting leakage, the circuit including a plurality of reference resistors. A divided voltage is compared with the resistance value of a leakage detection wire, so that the leakage position of the primary pipe is specified. The resistance value of the leakage detection wire differs at predetermined intervals, and the resistance values different at the predetermined intervals are compared with the reference resistors in the circuit, so that the double-pipe structure which can pinpoint the leakage position of the primary pipe can be achieved.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to piping systems for supplying fuels such as gasoline, diesel, and petroleum; piping systems for supplying organic solvents such as toluene, xylene, ketones, and alcohol; and piping systems for liquids such as bases such as sodium hydroxide, colloids such as paint and milk, and water, and in particular to a double piping structure for detecting leaks of liquids flowing in such piping. [Background technology]

[0002] Conventionally, in piping systems that supply fuel to fuel tanks, piping systems that supply organic solvents to solvent tanks that store them, and piping systems for liquids such as water, confirmation of leaks in piping supply lines has relied on, for example, visual inspection by facility staff or maintenance workers.

[0003] However, such visual inspections often result in overlooking (forgetting to inspect) necessary areas, and in particular in the case of buried pipes buried underground, laborious and time-consuming work such as digging up the pipes is required. Therefore, an invention has been proposed for a double-pipe structure that doubles the pipes to detect liquid leaks within the pipes, as a pipe that can be easily and reliably inspected automatically for fuel leaks, etc.

[0004] However, the double-wall piping structure is currently used only in fueling facilities such as gas stations, and is not widely used in general factories or other facilities. For example, various types of piping are used in chemical plants, energy industries such as electricity and gas, and water facilities, but double-wall piping for leak detection has not been adopted. As a result, the above-mentioned time-consuming and laborious maintenance work is required.

[0005] In particular, the working fluid flowing through the pipes may be at high temperature, high pressure, or contain chemicals that are harmful to the human body, making maintenance work difficult.

[0006] Furthermore, such facilities are typically operated 24 hours a day, and if a leak occurs in the piping, it is necessary to identify and repair the leak as quickly as possible, without shutting down the facility.

[0007] In conventional methods (for example, Patent Document 1), an injection jig is attached to the leaking pipe, and the jig heats and softens the sealant, which is then injected into the pipe to repair the leak. However, with conventional methods, it is difficult to pinpoint the leak location, reliably identify the leak position, and repair the leak location in a short period of time. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-78348 Summary of the Invention [Problem to be solved by the invention]

[0009] Therefore, the present invention proposes a double piping structure for piping used in places other than fueling facilities such as gas stations, such as chemical plants, energy industries such as electricity and gas, and water facilities, and also proposes a double piping structure that can pinpoint the leak location of various liquids, not just fuels and solvents, but also alcohol, water, etc., and can accurately detect liquid leaks from piping due to the occurrence of corrosion holes or pitting holes. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides a primary pipe through which at least oils such as gasoline, organic solvents such as toluene, xylene, acetone, alcohol, and ethyl acetate, bases such as sodium hydroxide, colloids such as paint and milk, and liquids such as water flow; a secondary pipe that is installed outside the primary pipe and covers it with a predetermined gap; This can be achieved by providing a double piping structure comprising: a leak detection line arranged in a straight line along the gap located on the lower surface of the lower part of the primary piping and the upper surface of the lower part of the secondary piping, which detects leakage of gasoline or oil liquids other than gasoline from the primary piping; and an oil leak alarm device which alerts the public to leakage from the piping based on a signal detected by the leak detection line, wherein the oil leak alarm device includes an oil leak detection circuit which detects the leakage, and has a plurality of standard resistors within the circuit, and is configured to identify the leak location in the primary piping by comparing the divided voltage with the resistance value of the leak detection line, and the resistance value of the leak detection line varies at predetermined intervals, and the leak location in the primary piping can be pinpointed by comparing the different resistance values ​​at predetermined intervals with the standard resistor within the circuit. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a conceptual diagram illustrating a piping structure according to the present embodiment. [Figure 2] FIG. 2 is a diagram illustrating the piping configuration, and is a perspective view of the double piping structure of this example. [Figure 3] 1B is a cross-sectional view of the double piping structure of this example, and FIG. 1B is an enlarged view of part A shown in FIG. [Figure 4] 3(b) (cross-sectional view taken along line CC), and includes an enlarged view of a circled portion D and an enlarged view of a circled portion E. FIG. [Figure 5] FIG. 2 is a perspective view illustrating the structure of a pipe through which the leak detection line is taken out to the outside. [Figure 6] 1 is a circuit diagram showing an example of an oil leakage detection circuit used in an oil leakage detection device. [Figure 7] FIG. 10 is a perspective view of a piping according to a second embodiment. [Figure 8] FIG. 10 is a circuit diagram showing another example of an oil leakage detection circuit used in the oil leakage detection device of the second embodiment. [Figure 9] FIG. 10 is a diagram showing the configuration of a leak detection line used in the third embodiment. [Figure 10] FIG. 10 is a circuit diagram showing another example of the oil leakage detection circuit used in the oil leakage detection device of the third embodiment. [Figure 11] FIG. 10 is a circuit diagram showing still another example of the oil leakage detection circuit used in the oil leakage detection device of the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. (First embodiment) 1 is a conceptual diagram illustrating a double piping structure according to an embodiment of the present invention, which is used to transport petroleum fuels such as gasoline refined in a chemical plant and organic solvents such as toluene. The example of underground facilities shown in Figure 1 stores products refined by a chemical plant, and includes, for example, one or more underground gasoline tanks 1 that store gasoline, underground kerosene tanks 2 that store kerosene, underground MCH tanks 3 that store MCH (methylcyclohexane: first organic solvent) which is a hydrogen carrier, underground toluene tanks 4 that store toluene (second organic solvent) obtained by dehydrogenation of MCH, and underground alcohol tanks 5 that store alcohol.

[0013] Incidentally, today, organic solvents such as toluene, xylene, and acetone are widely used in painting, cleaning, printing, and other operations. For example, toluene is widely used as a solvent for paint, paint thinner, printing ink, adhesives, etc., and xylene is also used as a solvent for adhesives and paints, and they are used in a wide range of applications.

[0014] The gasoline filled in underground tank 1 is transported, for example, by a tanker truck. The kerosene filled in underground kerosene tank 2, the MCH filled in underground MCH tank 3, the toluene filled in underground toluene tank 4, and the alcohol filled in underground alcohol tank 5 are also transported, for example, by tanker trucks.

[0015] Furthermore, one or more fuel supply equipment 6a, reformer 6b, compressor 7, pressure accumulator 8, and dispenser 9 are installed on the ground.

[0016] The fueling equipment 6a is equipment for supplying gasoline stored in the underground gasoline tank 1 to a gasoline vehicle 12. The reformer 6b is a system that extracts MCH from the underground MCH tank 3, burns kerosene stored in the underground kerosene tank 2, heats the extracted MCH, and separates and refines hydrogen.

[0017] The compressor 7 compresses and liquefies the gaseous hydrogen purified by the reformer 6b. The accumulator 8 is used to store the liquefied hydrogen. The dispenser 9 is a facility for filling the hydrogen stored in the accumulator 8 into an FCV (fuel cell vehicle) 13.

[0018] FIG. 2 is a perspective view of the double piping structure of this example, illustrating the piping configuration connecting underground tanks 1 to 5 storing gasoline, kerosene, MCH, toluene, and alcohol to the ground.

[0019] As shown in the figure, the pipe 14 has a primary pipe 15 made of resin covered by a secondary pipe 16 made of the same resin, and a gap 17 of a predetermined width is formed between the primary pipe 15 and the secondary pipe 16. The leak detection line 11 described above is disposed in this gap 17. The primary pipe 15 and the secondary pipe 16 are not limited to being made of thermoplastic resin such as polyethylene or polyamide, but may also be made of thermosetting resin such as phenolic resin or epoxy resin.

[0020] FIG. 3(a) is a cross-sectional view of the piping 14 (cross-sectional view taken along line BB in FIG. 2), and FIG. 3(b) is an enlarged view of the dotted circled area A in FIG. 3(a). As described above, the piping 14 has a double structure, with the secondary piping 16 covering the primary piping 15. As shown in FIGS. 3(a) and 3(b), the leak detection line 11 is disposed in the gap 17 between the primary piping 15 and the secondary piping 16 to detect leakage from the primary piping 15. The leak detection line 11 is disposed linearly on the underside of the primary piping 15 (the upper surface of the secondary piping 16). Therefore, even if toluene, for example, flowing through the primary piping 15 leaks from a defect formed in the primary piping 15, the leaked toluene flows down along the outer surface of the primary piping 15, and can be reliably detected by the leak detection line 11. Furthermore, the secondary pipe 16 acts as a receiver, preventing leaked substances such as toluene and alcohol from flowing outside and contaminating the soil.

[0021] 4 is a cross-sectional view (cross-sectional view along line CC) of FIG. 3(b) above, and shows the wiring configuration of the leak detection line 11 arranged in the gap 17 between the aforementioned primary pipe 15 and secondary pipe 16. As shown in the figure, the leak detection line 11 is arranged linearly along the lower surface of the primary pipe 15 (the lower upper surface of the secondary pipe 16), and can reliably detect, for example, toluene or alcohol leaking from a defect in the primary pipe 15.

[0022] The configuration of the leak detection line 11 will be explained by enlarging the circled portion D in the figure. The leak detection line 11 is made up of an oil absorption portion 19 and a detection portion 20. The oil absorption portion 19 is made up of, for example, a fluororesin film that has the property of absorbing oils such as gasoline, and the detection portion 20 detects the oil sucked in by the oil absorption portion 19. As shown in the schematic diagram further enlarging the circled portion E in the figure, when oil comes into contact with the detection portion 20 through the oil absorption portion 19, the oil penetrates the element 21 of the detection portion 20, changing the resistance value of the detection portion 20. This change in resistance value is notified to the oil leak detection monitor via a cable (not shown).

[0023] Figure 5 shows the structure of the piping through which the leak detection wire 11 is taken out, and this piping 23 is basically a double piping structure consisting of the above-mentioned primary piping 15 and secondary piping 16, but is provided with a wiring outlet 22 through which the leak detection wire 11 is taken out. Note that the piping 23 shown in the figure has the above-mentioned normal double piping, for example 24, connected to the front and back, and multiple of these piping 23 and 24 are connected, and the leak detection wire 11 is wired through all of the double piping. Note that the leak detection wire 11 is made of fluororesin as mentioned above, and has excellent weather resistance and chemical resistance.

[0024] By wiring the leak detection wire 11 in a straight line along the underside of the pipe 14 in this way, even if a leak occurs from a defective part of the pipe, the leak detection wire 11 can reliably detect the leak and notify the oil leak detection monitor via the cable. That is, as shown in the schematic diagram of Figure 4, when oil comes into contact with the detection unit 20 through the oil absorption part 19, the oil permeates the element 21 of the detection unit 20, changing the resistance value of the detection unit 20. This change in resistance value is notified to the oil leak detection monitor as described above.

[0025] Figure 6 shows an example of an oil leak detection circuit used in an oil leak detection monitor. As shown in the figure, the oil leak detection circuit 25 is composed of, for example, a transistor Tr, a voltage dividing resistor R, a resistor r, and a leak detection line 11. The voltage value of the power supply E is divided by the resistance value of the leak detection line 11 and the resistance value of the voltage dividing resistor R, and when the resistance value of the leak detection line 11 reaches a predetermined value or higher, a leak detection signal is output from the collector of the transistor Tr. Therefore, the oil leak detection device uses this signal to alert the outside world to a leak, for example by lighting or flashing an LED. The oil leak detection device also uses a speaker to notify the outside world of the leak. Therefore, in this example, the piping is made double-layered and linear detection sensors are arranged in the gaps between the piping, making it possible to detect leaks of, for example, toluene or alcohol, and prevent leakage into the ground.

[0026] (Second embodiment) Next, a second embodiment of the present invention will be described. In the above description of the first embodiment, a single pipe 23 provided with a wiring outlet 22 was used, but the double pipe structure of this embodiment is configured to use multiple pipes 23 provided with wiring outlets 22, and a leak detection line 11 is drawn out from each of the wiring outlets 22. With this configuration, it is possible to pinpoint the location of a leak of, for example, toluene from the pipe 14. This will be explained in detail below.

[0027] 7 is a perspective view of the double piping structure of this embodiment. As shown in the figure, in the double piping structure of this example, pipes 23 provided with wiring outlets 22 and pipes 24 not provided with wiring outlets 22 are arranged alternately, adjacent pipes 23 and 24 form a pair, and leak detection wire 11 is drawn out from the wiring outlet 22 of the corresponding pipe 23.

[0028] For example, in the example shown in the figure, adjacent first pipes 23-1 and 24-1 form a pair, and a leak detection wire 11-1 is drawn out from a wiring outlet 22-1 provided on one of the pipes, 23-1. Similarly, adjacent second pipes 23-2 and 24-2 form a pair, and a leak detection wire 11-2 is drawn out from a wiring outlet 22-2 provided on one of the pipes, 23-2. Similarly, adjacent third pipes 23-3 and 24-3 and subsequent pipes, a leak detection wire 11-3 is drawn out from a wiring outlet 22-3 provided on one of the pipes, 23-3, and a leak detection wire 11-4 is drawn out from a wiring outlet 22-4 provided on pipe 23-4, and this piping configuration is continuous.

[0029] 8 shows an example of a detection circuit for detecting leaks of, for example, toluene in the piping structure configured as described above, and specifically, this can be realized by using the oil leak detection circuit shown in the figure. That is, a circuit of transistors Tr1, Tr2, Tr3, ..., voltage dividing resistors R1, R2, R3, ..., and resistors r1, r2, r3, ... is created corresponding to each leak detection line 11-1, 11-2, 11-3, ..., and in each circuit, the voltage value of power supply E is divided by the resistance value of leak detection lines 11-1, 11-2, 11-3, ... and the resistance value of voltage dividing resistors R1, R2, R3, ..., and the location of the leak in the piping is identified by outputting a leak detection signal from the collector of transistor Tr when the resistance value of leak detection line 11-1, 11-2, 11-3, ... reaches a predetermined value or higher.

[0030] For example, if a leak detection signal is detected from output 1, it is known that there is a leak at the location of the corresponding pipe 23-1 or 24-1, and this piping section should be repaired. Also, if a leak detection signal is detected from output 2, it is known that there is a leak at the location of the corresponding pipe 23-2 or 24-2, and this piping section should be repaired. This applies in the same way, and therefore the piping section to be repaired can be pinpointed in advance, allowing excavation work, repair work, etc. to be carried out efficiently, making this a highly effective double piping system.

[0031] (Third embodiment) Next, a third embodiment of the present invention will be described. In the above description of the second embodiment, an example was given in which a plurality of leak detection lines 11-1, 11-2, 11-3, ... were used, but in this embodiment, even when a single leak detection line is used, the location of the leak can be pinpointed by using an element whose detection section has different resistance values ​​depending on the location of the leak detection line, for example. This will be explained in detail below.

[0032] FIG. 9 is a diagram showing the configuration of the leak detection line 31 used in this embodiment. As shown in the figure, the leak detection line 31 used in this example uses an element 33 whose detection section 32 has different resistance values ​​depending on its installation position. For example, the resistance value of the first predetermined width L1 of the leak detection line 31 is set to R31-1, the resistance value of the next predetermined width L2 is set to R31-2, the resistance value of the next predetermined width L3 is set to R31-3, and so on, with the resistance value changing for each subsequent predetermined width as R31-4, R31-5, and so on. By using a leak detection line 31 configured in this way, it is possible to identify the location of a leak such as gasoline.

[0033] FIG. 10 is a diagram for explaining the circuit configuration (oil leak detection circuit 27) used in this example. In this case, a signal from one leak detection line 31 is input to the leak detection line 31, and by varying the resistance values ​​of the voltage dividing resistors R1, R2, R3, etc. according to the position of the piping, an output can be obtained from the position of the transistor Tr corresponding to the leak position. For example, By matching the resistance value to the resistance change of the detection section 32 (element 33) of the leak detection line 31 at a certain position in the piping, if there is a detection output from the output of the transistor Tr, it can be determined that the leak is from the corresponding position in the piping.

[0034] Specifically, by matching the resistance value of voltage dividing resistor R1 to the resistance change of detector 32-1 (element 33-1) at resistor R31-1 on leak detection line 31, if there is a detection output (output 1) from transistor Tr1, it is determined that there is leakage from position L1 on the pipe. Also, by matching the resistance value of voltage dividing resistor R2 to the resistance change of detector 32-2 (element 33-2) at resistor R31-2 on leak detection line 31, if there is a detection output (output 2) from transistor Tr2, it is determined that there is leakage from position L2 on the pipe. Similarly, by matching the resistance value of voltage dividing resistor R3 to the resistance change of detection unit 32-3 (element 33-3) at the position of resistor R31-3 on the leakage detection line 31, if there is a detection output (output 3) from transistor Tr3, it is determined that there is leakage from position L3 on the piping, and by matching the resistance value of voltage dividing resistor R4 to the resistance change of detection unit 32-4 (element 33-4) at the position of resistor R31-4 on the leakage detection line 31, if there is a detection output (output 4) from transistor Tr4, it is determined that there is leakage from position L3 on the piping.

[0035] In addition, the example shown in Figure 11 is a case where there is a leak at position L2 of the pipe, for example. In this case, there is a change in the resistance value of the detection unit 32-2 (element 33-2), and the detection output (output 2) of transistor Tr2 indicates that there is a leak at position L2 of the pipe.

[0036] Therefore, in this example, the pipe location to be repaired can also be pinpointed in advance, allowing for efficient excavation work, repair work, etc., making this a highly effective double piping system. The above-mentioned predetermined width can be set arbitrarily, for example, from intervals of several tens of centimeters to several meters, as needed.

[0037] In the above explanation of the first to third embodiments, the fuel filling pipe 2 of a gas station has been described as an example, but the same can be applied to the fuel supply pipe 3. In addition, in the above explanation, the example of an underground buried tank of a gas station has been described, but the same can be applied to underground piping for other underground tank storage facilities, fuel filling stations, etc.

[0038] This example is not limited to underground piping, but can also be applied to exposed piping in coastal areas where corrosion is likely to occur, and to long-distance piping. Furthermore, although the above explanation has been given for resin piping, it can also be applied to double piping made of steel or FRP (fiber reinforced composite material), etc.

[0039] Furthermore, the oil leakage detection circuit diagrams in Figures 6, 8, and 10 described in this example are just examples, and it goes without saying that the circuits for detecting leakage of, for example, toluene, etc. in the double piping structure of the present invention are not limited to the above examples.

[0040] In addition to toluene and alcohol, the same process can be carried out with organic solvents such as acetone and ethyl acetate, bases such as sodium hydroxide, colloids such as paints and milk, and liquids such as water.

[0041] Furthermore, in the configuration of pipes 23 and 24 described in the second embodiment, a leak detection line 11 may be used for every two pipes 24 for one pipe 23, or a leak detection line 11 may be used for every three pipes 24 for one pipe 23, or even a leak detection line 11 may be used for every four or more pipes 24 for one pipe 23. [Explanation of symbols]

[0042] 1. Underground gasoline tank 2. Underground kerosene tank 3. MCH underground tank 4. Toluene underground tank 5. Alcohol 6a··Fueling equipment 6b Reformer 7. Compressor 8. Accumulator 9. Dispenser 10. Tank truck 11. Leak detection wire 14 Piping 15 Primary piping 16 Secondary piping 17. Gap 19...Oil absorption part 20. Detection unit 21 elements 22, 22-1, 22-2, 22-3... Wiring outlet 23, 23-1, 23-2, 23-3, Piping 24, 24-1, 24-2, 24-3, Piping 31 Leak detection wire 32, 32-1, 32-2, 32-3, Detector 33, 33-1, 33-2, 33-3, etc. elements E...Power supply L1,L2,L3,...predetermined width Tr1, Tr2, Tr3, etc. transistors R1, R2, R3, etc. voltage dividing resistors R31-1, R31-2, R31-3, etc. Resistance of the detection section r1, r2, r3,...resistance

Claims

1. a primary pipe through which at least oils such as gasoline, organic solvents such as toluene, alcohol, xylene, acetone, and ethyl acetate, and liquids such as water flow; a secondary pipe that is installed outside the primary pipe with a predetermined gap therebetween; a leak detection line that is linearly arranged along the gap located between the lower surface of the lower portion of the primary pipe and the upper surface of the lower portion of the secondary pipe, and that detects leakage of oils such as toluene, alcohol, xylene, acetone, ethyl acetate, and other organic solvents, as well as water, from the primary pipe; an oil leakage alarm device that notifies the outside of a leakage from the piping based on a signal detected by the leakage detection line, The oil leakage alarm device includes an oil leakage detection circuit that detects the leakage, and is provided with multiple standard resistors within the circuit, and is configured to identify the leakage point in the primary piping by comparing the divided voltage with the resistance value of the leakage detection line, and the resistance value of the leakage detection line varies at predetermined intervals, and the leakage point in the primary piping is pinpointed by comparing the different resistance values ​​at predetermined intervals with the standard resistor within the circuit.

2. The double piping structure described in claim 1, characterized in that the leak detection line is composed of an oil absorption section and a detection section, and the oil absorption section absorbs oil components of gasoline or oils other than gasoline, and the detection section detects leaks.

3. 3. The double piping structure according to claim 2, wherein the detection unit detects the leakage based on a resistance value that changes as the oil penetrates.

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