JP2014206414A - Thickness measurement device of underground tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thickness measurement device of an underground tank capable of accurately measuring the thickness of a steel plate and FRP of the underground tank buried especially in a gasoline station or the like.SOLUTION: The thickness measurement device of an underground tank includes: a steel plate constituting a housing of the underground tank; an FRP disposed on a surface of the steel plate by adhesion or coating; and a thickness measurement instrument having first measuring means for measuring the thickness of the FRP and second measuring means for measuring the thickness of the steel plate.

Description

  The present invention relates to a thickness measuring device for measuring the thickness of steel plates and FRPs in underground tanks embedded in a gas station or the like.

  Conventionally, in welded steel structures such as tower tanks and spherical tanks, aging deterioration due to corrosion occurs, and inspection and repair by periodic plate thickness measurement are necessary. In particular, when the tank is buried underground, a crack or the like occurs when it becomes old, which causes oil leakage. For this reason, inspection by periodic plate thickness measurement is required.

  For example, in Patent Document 1, ultrasonic probes and eddy current sensors are arranged in a staggered manner (alternately) and mounted on a traveling carriage in order to measure the thickness of a flat bottom plate of a cylindrical tank. A technique for measuring a steel plate thickness of a tank bottom plate plane by running a traveling carriage on the coating coated on the tank is disclosed.

JP 2001-50736 A

  However, in the above conventional method, in order to measure the plate thickness of the flat bottom plate of the cylindrical tank, the traveling carriage is run on the coating coated on the bottom plate surface of the cylindrical tank, and the steel plate thickness of the plane of the tank bottom plate is measured. Actually, there are fine irregularities on the plane of the tank bottom plate, and it is not possible to accurately measure the thickness of the buried tank.

  Accordingly, the present invention provides an underground tank thickness measuring device capable of accurately measuring the thickness of an underground tank embedded in a gas station or the like.

  According to the first aspect of the present invention, there is provided a first steel sheet that constitutes a housing of an underground tank, an FRP disposed on the surface of the steel sheet by sticking or coating, and a thickness of the FRP. This can be achieved by providing a thickness measuring device for an underground tank comprising a measuring means and a thickness measuring instrument having a second measuring means for measuring the thickness of the steel sheet.

  Moreover, the said subject can be achieved by providing the thickness measuring apparatus of the underground tank which the said thickness measuring device is an ultrasonic measuring device according to 2nd invention.

  According to a third aspect of the present invention, there is provided a thickness measuring device for an underground tank in which the measurement positions of the FRP and the steel plate measured by the first and second measuring means are processed flat. Can be achieved.

  Further, according to the fourth aspect of the present invention, the above object can be achieved by providing an underground tank thickness measuring device in which the underground tank is a tank buried underground in a gas station.

  According to the present invention, an underground tank thickness measuring device capable of accurately measuring the thickness of an underground tank buried in a gas station or the like is provided, and occurrence of cracks, pitting corrosion, corrosion, and the like is caused in advance. Can be prevented.

It is an external view of the plate | board thickness measuring apparatus of the burying tank of this invention. It is a figure explaining the internal circuit of a plate thickness measuring apparatus. It is a figure explaining the example which performs the thickness measurement of the underground tank which stores gasoline. It is a figure which shows the cross-sectional structure of an underground tank, and is AA 'cross section shown in FIG. It is a figure which shows the process at the time of actually measuring the thickness of a steel plate and FRP. It is a figure which shows the surface state of FRP, and the example by which the measurement location was planarized.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is an external view of an underground tank thickness measuring apparatus according to the present invention. In the figure, the thickness measuring device 1 can measure the thickness of metal, internally corroded metal, and FRP (Fiber Reinforced Plastics) using, for example, an ultrasonic reflection echo. It is also possible to measure the layer thickness. The FRP is a fiber reinforced plastic, for example, a composite material in which glass fiber is mixed into the plastic to improve the strength. FIG. 2 is a diagram for explaining an internal circuit of the thickness measuring apparatus 1.

  In both figures, the thickness measuring apparatus 1 converts an ultrasonic vibration signal into an ultrasonic wave and sends it to an FRP, which is a measured object, at a certain angle, and a reflected wave from the measured object. Is received at a position different from the transmitting vibrator 2 and converted into an electric signal, and a probe 4 containing the receiving vibrator 3, an ultrasonic vibration signal is given to the probe 4, and It comprises a measuring device 5 that forms a gate signal based on a reflected wave signal from the surface of the measuring body in the received signal from the probe 4 and measures the layer pressure such as FRP based on the gate signal. ing.

  Here, the measuring instrument 5 includes a transmission unit 6, a reception amplification unit 7, a detection gate circuit 8, a drive circuit 9, an operation unit 10, a display unit 11, and a CPU 12. The CPU 12 is a central processing unit of the measuring instrument 5 and controls each unit such as the transmission unit 6 and the reception amplification unit 7. The operation unit 10 is provided with a power button and various setting buttons, and the display unit 11 displays the thickness of the measurement object as a measurement result.

The measuring instrument 5 supplies a vibration signal having a predetermined frequency to the probe 4 from the transmitter 6 via the transmission terminal T. On the other hand, the detection signal from the probe 4 is supplied to the reception amplification unit 7 via the reception terminal 3. The output signal of the reception amplifying unit 7 is converted into a gate signal by the detection gate circuit 8, drives the drive circuit 9, and displays the thickness data of the measured object based on the reflected wave signal on the display unit 11.
The process which measures the thickness of FRP of an underground tank and a steel plate using the thickness measuring apparatus of this example below is demonstrated below.

  FIG. 3 shows an example of an underground tank for storing gasoline, for example. In the figure, an underground tank 15 is filled with gasoline, an oiling pipe 16 for charging gasoline, an oil supply pipe 17 for sucking gasoline from the underground tank 15, a ventilation pipe 18 for venting the underground tank 15, and a gasoline liquid stored in the underground tank 15. A liquid level gauge 19 for measuring the surface height is provided. The underground tank 15 is buried at a predetermined depth from the ground surface, and concrete (not shown) is provided on the underground tank 15.

  The oil supply pipe 16 is provided with an oil supply port 20 on the ground surface, and gasoline is supplied from the oil supply port 20. The refueling pipe 17 is provided with equipment 21 such as a meter and a pump on the ground surface, and sucks gasoline from the underground tank 15 and measures the sucked gasoline. The oil supply pipe 16 is provided with a valve 22, and the oil supply pipe 17 is provided with a valve 23. When the underground tank 15 is repaired / renovated, the valves 22 and 23 are closed. The vent pipe 18 is provided with a vent 24 for discharging gas generated in the underground tank 15.

  FIG. 4 is a diagram showing a cross-sectional configuration of the underground tank 15, and FIG. 3 is a diagram showing an AA ′ cross section of the underground tank 15. As shown in the figure, the underground tank 15 is composed of a steel plate 25 and an FRP 26, and the thicknesses of the steel plate 25 and the FRP 26 are measured using the thickness measuring device 1 described above from the direction of the arrow shown in the figure.

  FIG. 5 is a diagram showing a process for actually measuring the thicknesses of the steel plate 25 and the FRP 26. First, the thickness measuring device 1 is turned on, and the probe 4 is brought into contact with the position to be measured on the inner wall of the underground tank 15. Next, the transmission unit 6 is driven under the control of the CPU 12 to oscillate ultrasonic waves of a predetermined frequency from the transmission vibrator 2. This ultrasonic wave is reflected at the boundary between the steel plate 25 and the FRP 26, and the reflected wave is returned to the probe 4.

  The reply transducer 3 receives this signal, sends it to the reception amplification section 7, and amplifies the received signal. Thereafter, the reception signal amplified by the reception amplification unit 7 is input to the detection gate circuit 8 and the drive circuit 9 is driven to display the thickness data of the FRP 26 on the display unit 11. In the example shown in FIG. 1, for example, a measurement result of 2.00 mm is displayed.

  Next, an ultrasonic wave of another frequency is oscillated from the transmission unit 6 under the control of the CPU 12, and a reflected wave reflected at the end of the steel plate 25 by this ultrasonic wave is returned to the probe 4. The reply transducer 3 detects this signal and sends it to the reception amplification unit 7 as described above to amplify the reception signal. Thereafter, the reception signal amplified by the reception amplification unit 7 is input to the detection gate circuit 8 and the drive circuit 9 is driven to display the thickness data of the steel plate 25 and the FRP 26 on the display unit 11.

  On the other hand, there are fine irregularities on the surface of the FRP 26. In this example, as shown in FIG. 6, the measurement surfaces 26a, 26b, 26c,. Further, the measurement surfaces 26a, 26b, 26c,... Are flattened at a constant interval, and a more accurate layer pressure of the FRP 26 or the like can be measured.

  As described above, according to this example, it is possible to accurately measure the thickness of the FRP 26 and the like of the underground tank embedded in a gas station and the like, and by processing the measurement surface flat, more accurate laminar pressure can be obtained. Can be measured. Moreover, by performing repairs based on the measurement results, it is possible to prevent the occurrence of cracks, pitting corrosion, corrosion, etc. in the underground tank.

DESCRIPTION OF SYMBOLS 1 ... Thickness measuring apparatus 2 ... Transmitting vibrator | oscillator 3 ... Receiving vibrator | oscillator 4 ... Probe 5 ... Measuring instrument 6 ... Transmitting part 7 ... Reception amplification part 8... Detection gate circuit 9... Drive circuit 10 ..Operation unit 11 .. Display unit 12 ..CPU
15. ・ Underground tank 16 ・ ・ Lubrication pipe 17 ・ ・ Fuel pipe 18 ・ ・ Ventilation pipe 19 ・ ・ Liquid level gauge 20 ・ ・ Lubrication port 21 ・ ・ Equipment 22, 23 ・ ・ Valve 25

Claims (4)

A steel plate constituting the housing of the underground tank;
FRP disposed on the surface of the steel sheet by sticking or coating;
A thickness measuring instrument having first measuring means for measuring the thickness of the FRP, and second measuring means for measuring the thickness of the steel sheet;
An underground tank thickness measuring device comprising:   3. The underground tank thickness measuring apparatus according to claim 2, wherein the thickness measuring instrument is an ultrasonic measuring instrument.   3. The underground tank thickness measuring device according to claim 1 or 2, wherein the FRP and the steel plate measuring positions measured by the first and second measuring means are processed flat.   4. The underground tank thickness measuring device according to claim 1, wherein the underground tank is a tank embedded in a base of a gas station.

Images