JPH02140370A - Construction execution of petroleum tank - Google Patents

Abstract

PURPOSE:To prevent the intrusion of rainwater from a gap and prevent corrosion by covering the part between an annular plate laid on the periphery of the bottom plate of a tank and a foundation by a noncombustible light-hardened resin sheet over the whole periphery. CONSTITUTION:A tank 10 having a bottom plate 8 and au annular plate 9 is installed onto a foundation part 5 which is formed slightly high. Then, the part between the annular plate 9 and the foundation part 5 is covered with a noncombustible light-hardened resin sheet 14 over the whole periphery and fixed. Therefore, even if a gap is generated between the foundation part 5 and the annular plate 9 because of the welding strain of the tank 10, deformation of the annular plate 9, sinking of the ground, etc., intrusion of reinwater is prevented. Therefore, the corrosion of the bottom part of the tank is prevented, and the repair cost can be reduced.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a novel oil tank construction method, particularly an annual oil tank construction method.
This invention relates to a method of constructing an oil tank that can easily prevent rainwater from entering between the board and the foundation.

[Conventional technology]

Currently, more than 10,000 oil tanks are installed in various parts of Japan for refineries, reservoirs, and stockpiling bases. The capacity of each tank is 50Kf for small, 17 to 150,000Kf for large.
f and accordingly the diameter of the respective tank ranges from 4 m to 95 m. Incidentally, the average capacity of oil tanks related to reservoirs is 1500 kg, but the average capacity of oil tanks related to oil refineries is 30 kg.
0OOK, Q.

In terms of stockpiling bases, the average size is about 100,000KN.

Such oil tanks are usually constructed as follows. That is, in Figures 1 to 3 of the drawings, crushed stone, soil 2, etc. are first piled up at a certain height on the surrounding flat land 1, and the center of the surface is a horizontal part 3 that is approximately circular, and the surrounding area is approximately 1/1
Slope section with a slight slope of 0 to 1/20 (kenbashiri)
Slope section with a somewhat steep slope of 4 and 1/2 to 1/3 (
A base portion 5 is formed on which a slope (4') is provided. The surfaces of the horizontal portion 3 and the inclined portions 4 and 4' are covered with asphalt mortar 6. In this drawing, the end of the inclined portion 4 is surrounded by concrete 7.

A bottom plate 8 made of a rectangular steel plate of a certain size is laid down in a circular shape on the three horizontal surfaces and welded and joined together. Then, an annular plate 9 is laid in an annular manner around this circular bottom plate.

In this case, the circumference is divided into an appropriate number of equal parts, and steel plates of each width are laid down and welded together. Several side plates 10 are arranged and welded in a circumferential manner on the annular plate 9, and these are welded together in several stages to cover a rear roof (not shown) to form an oil tank body 11.

When rain falls on the oil tank 12 constructed in this way, the overhanging portion of the roof and surrounding annular plate 9, that is, the side plate 10
Since the asphalt mortar covering layer 6 of the surrounding foundation part 5 has almost no water permeability, rainwater falling on the outer part does not penetrate into the foundation and flows down from the slope part 4 to the ground outside the foundation. However, there is a gap 13 between the lower part of the annular plate 9, commonly called the hem area, and the upper surface of the foundation part 5, and rainwater can also enter this gap 13, leading to corrosion in this area.

The causes of this gap are: 1. Unavoidable distortion caused by the construction accuracy of the foundation surface and the welded structure of the tank body. 2. Moment generated in the annular plate/side plate due to changes in the level of the stored oil and load fluctuations. deformation of the annular plate due to

3. Due to ground subsidence, there may be a vertical shift between the outer part of the foundation and the foundation under the tank body, that is, the annular plate part, and there is usually a gap of 2 to 3 mm, but in severe cases, a gap of 5 to 6 mm in parts13. occurs.

When rainwater intrudes into the gap between the annular board and the asphalt mortar covering part of the foundation, significant corrosion occurs on the back surface of the annular board, which requires a great deal of cost and construction time to repair. In order to prevent such adverse effects, conventionally both the annular plate section and the base section are laminated and covered with a rubber sheet, a Teflon (tetrafluoroethylene) sheet, or the like.

During construction, these sheets are packed in boxes and transported to the site and laminated there, which is a time-consuming process, especially when constructing around large-capacity, large-diameter tanks. Furthermore, the adhesive used here is transported to the site in oil cans, prepared and used there, and is quite time-consuming, requiring 5 to 10 days for construction.

It takes a long period of one to two weeks for the laminated and coated sheet to harden, during which time it is impossible to walk on the area, and if you do, it will deform and you will have to start over again. After about six months of continued use, UV rays will cause the material to deteriorate and crack, making it difficult to prevent rainwater from entering the gap between the annual board and the foundation. There were some drawbacks, such as the need for

[Purpose of the invention]

Therefore, an object of the present invention is to solve these difficulties and to construct an oil tank that can satisfactorily prevent rainwater from entering the gap between the annular plate part and the foundation part of the oil tank with a simple operation. The purpose is to provide a method.

[Structure of the invention]

Therefore, the present invention comprises a base part which is formed in a circular shape slightly higher than the surrounding level ground and whose surface is covered with asphalt mortar, a circular bottom plate laid in the center above the base part, and an annular plate arranged around the base part in a circular shape. A flame-retardant photocurable resin sheet is applied over the annular plate and the surrounding base portion of an oil tank having a tank body, which is formed by laying a side plate vertically on the annular plate and further providing a roof. The present invention provides a method for constructing an oil tank, which is characterized by coating the oil tank.

C Detailed description of the invention] The present invention will be explained in more detail.

In the present invention, when constructing an oil tank as described above, a flame-retardant photocurable resin sheet 14 is provided between the overhanging part of the annual plate 9 and the asphalt mortar coating 6 of the foundation part 5.
(Figures 3 to 5). This sheet can be made by impregnating a modified vinyl ester resin, such as epoxy acrylate, with a flame retardant and a photosensitizer, into a sheet, or by impregnating matte glass fibers and forming a roll including a release paper. A sheet having a thickness of about 1 m11 and manufactured by Showa Kobunshi Co., Ltd. under the trade name Ripoxy VS100OM (flame retardant) can be suitably used.

In addition to this, the putty or varnish used to adhere this sheet is made of a similar material, and the product name is Ripoxy VS.
-100 (flame retardant) or VS-200 in liquid form
(flame retardant) can be suitably used.

These materials have excellent heat resistance and corrosion resistance comparable to epoxy, high strength, and crystal formability comparable to unsaturated polyester, as well as photocuring properties that quickly harden through a chemical reaction when irradiated with light (ultraviolet rays). Since it is difficult to burn and has flame retardancy that satisfies the provisions of the Fire Service Act, it can be used very well for the purpose of the present invention.

When using this sheet for construction, first remove the rust and scale adhering to the overhanging part of the annular board by using a wire.
Remove with a brush, etc. There is no need to remove the adhered base paint. Meanwhile, moisture, dust, etc. on the asphalt mortar covered foundation are removed. If there are significant irregularities, apply putty as appropriate to smooth the surface to which the sheet is attached.

A thin layer of varnish 15 is applied with a brush to the surface to be attached to the annular plate 9 (FIG. 5). The resin sheet 14 having a width of 200 mm is cut with scissors to a suitable length of about 500 to 800 mm depending on the curvature.

In the adhesion process, the release paper attached to the resin sheet product is turned face up and is pressed by hand against the annular temporary so that it is brought into close contact with the adhesion surface as much as possible so that there are no gaps. Also, lightly press it against the base, and then remove the release paper. The adhesive should be attached to the annular board for 20 to 30 m+s. When attaching the second and subsequent sheets, overlap them by about 10 mm on the inner annular plate side16, and butt both ends on the outer circumferential foundation side1.
7. The varnish 15 is applied to the contact area. Be careful to finish pasting the sheet around the tank each month within the photo-curing time of this sheet.

The lipoxy VS100OM (flame retardant) sheet is cured by sunlight (ultraviolet light) in 10 to 20 minutes.

In addition, in order to avoid stress concentration caused by displacement of the annular plate and the foundation end due to fluctuations in the amount or load of oil stored in the oil tank and the subsidence of the foundation, and to prevent hair cracks from forming in the asphalt mortar. , spread the adhesive sheet lightly by hand to avoid wrinkles in each part, and then
The sheet is manually pressed along the step 18 between the end of the board and the asphalt mortar covering of the base so that the sheet is brought into close contact with the annular board or the base.

This is good because the flexible resin sheet can follow the above-mentioned displacement.

〔Effect of the invention〕

By coating a flame-retardant photocurable resin sheet between the annular plate part and the asphalt mortar covering part of the foundation part as in the present invention, the work can be done in the following way compared to the case of conventional rubber sheets etc. It has good properties and properties, and can prevent rainwater from entering the gap by shielding the gap between the two parts from the outside, thereby effectively preventing corrosion of the surrounding area.

That is, since the only materials required are a resin sheet like an adhesive tape and putty or varnish, transportation is simple and there is no need for troublesome preparation work on site. Furthermore, this sheet is usually thin and flexible, with a thickness of about 1 m11, so it is easy to install (and has good adhesion after hardening) and can withstand fluctuations in load caused by external forces.

Moreover, the only tools required are scissors and brushes, which are usually used, and there is no need to use special tools. Further, the work does not require much experience or skill, and the work time can be shortened accordingly. Therefore, costs including material costs and labor costs can be reduced considerably, making it truly economical and efficient. In addition, it remains in good condition without cracking even when used for a long period of time under harsh environmental conditions.

〔Example〕

Example 1 A flame-retardant photocurable resin sheet according to the present invention was pasted around an oil tank with a capacity of 1200 KfI and a diameter of 11.6 rn located in Ibaraki Prefecture.

This tank is currently under open inspection, and after the painting and foundation work is completed, we will take precautions to prevent paint from adhering to the tank.
After removing the masking tape (duct tape, etc.) from the part of the annual board where the sheet is to be attached, use a wire brush to remove loose rust, dust, etc. Apply the product name Ripoxy V at a position approximately 20 degrees inward from the outer periphery of the annular plate.
Apply S-200 (flammable) varnish. Similarly, apply the varnish on the base portion approximately 180 degrees outward from the outer periphery of the annular plate. However, I did not fill it with putty.

The product name Lipoxy V is 200mm wide and 11mm thick.
A S100OM (flame retardant) resin sheet is cut with scissors to a length of 680 mm, and is pasted on the varnished area.

In adhering, almost no roller was used, and the adhesive was applied by hand over the release paper, including the annular board, the base, and the stepped portion in between, to avoid wrinkles. For the second and subsequent sheets, the inner annular plates were overlapped by about 10 ann, the outer edges were abutted, varnish was applied to the joints, and the sheets were attached in the same manner. Although it was cloudy that day, the 6 pieces of sheet hardened in about 15 minutes, and the entire area around the tank was completed in about 1 hour by 3 people.
Finished in time. No abnormalities were found when a firefighter attended the inspection two days after the rain.

Example 2 A resin sheet was pasted in the same manner as in Example 1 around an oil tank with a capacity of 114,400 Kfi and a diameter of 37.7 m that was being used in the Kanagawa system. The weather on that day was sunny and 6 pieces were 10.
Hardened in minutes. The work was completed in 180 minutes by three people. Approximately 8 months have passed since the construction, including the winter, and during that time the oil level in the oil tank has fluctuated approximately 100 times, from a minimum of 3.9 m to a maximum of approximately 11.6 m, and the sheet attachment area changes accordingly. Although repeated load fluctuations were applied, no abnormalities such as rainwater infiltration into the gap between the annual plate and the foundation, corrosion of the annual plate, or cracks in the sheet were observed, and the product functioned as expected. was held.

[Brief explanation of the drawing]

The drawings are all explanatory diagrams for explaining the present invention in detail, and FIG. 1 is a partial elevation view of the oil tank, FIG. 2 is a plan view of the same, and FIG. 3 shows a sheet pasting part. FIG. 1 is an enlarged cross-sectional view of section A, FIG. 4 is a plan view showing the attached state, and FIG. 5 is a perspective view. 1... Surrounding flat area, 2... Crushed stone layer, 3... Planar part of the foundation, 4... Gentle slope of the foundation, 4'... Slightly steep slope of the foundation, 5 ...Foundation part, 6...Asphalt mortar covering part, 7...Concrete, 8...
・Bottom plate, 9... Annular plate, 10... Side plate, 11
...tank body, 12... entire oil tank, 13.
... Gap part, 14... Resin sheet, 15... Varnish, 16... Overlapping part, 17... Butting part,
18...Step part. Tame 1 Figure

Claims (1)

[Claims] A foundation part is formed in a circular shape slightly higher than the surrounding flat land and the surface is covered with asphalt mortar, a bottom plate is laid in a circular shape in the center above the foundation part, an annular plate is laid in a ring shape around it, and the annular A petroleum tank having a tank body having a side plate vertically disposed on the plate and a roof further comprising a flame-retardant photocurable resin sheet covering the annular plate and the surrounding base portion. Tank construction method.