JP2001122387A - Multistage tower and tank and fabrication method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for mounting a manhole, while the strength of a cylindrical intermediate side wall between an upper and lower tanks is being reinforced and to provide multistage towers and tanks made of FRP each having a manhole. SOLUTION: In the multistage towers and tanks made of FRP, a structure for a manhole is inserted into an insertion hole of a side wall, and a coating layer is formed from a curable composition for FRP from a body part of the manhole structure via the insertion hole to a side wall of a cylindrical intermediate part and the composition is cured to fix a manhole. With regard to the coating layer, the coating range of the layer on the wall of the cylindrical intermediate part is 1.0-1.5 times the distance, in the case of a prism-shaped manhole, between the center of the manhole and the vertical or horizontal side thereof, with respect to the insertion hole, and in the case of a cylindrical manhole, the coating range is 1.0-1.5 times the radius of the manhole. The thickness of the layer is 1.5-2.5 times the thickness of the side wall.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber reinforced plastic multistage tower having excellent corrosion resistance and a space-saving structure. In particular, the present invention relates to a multi-stage made of fiber-reinforced plastic (hereinafter also referred to as FRP) having an intermediate cylindrical space made of fiber-reinforced plastic provided with manholes for workers to enter and leave between upper and lower tanks of a multi-stage tower tank. It relates to a type tower tank.

[0002]

2. Description of the Related Art In the food industry, from small varieties and mass production,
With the diversification of customer needs, it is shifting to high-mix low-volume production. In accordance with such a tendency, a tank for storing and storing produced multi-type foods before shipment tends to be downsized. However, when a small tower is arranged on a plane, it occupies a large area in a site or a factory building. Therefore, it is becoming common to use a two-stage or more multi-stage tower.

[0003] Such a multi-stage column tank is basically constructed as shown in FIG.
Conventionally, as each tank, a steel tank whose inner surface is resin-lined is mainly used, and both tanks 2, 3 are stacked between the two tanks. By joining the tubular structure portions 2 ', 3' joined to the tank, a tubular intermediate portion 4 which is a working space where an operator can enter and exit is formed, and a trunk portion of the tubular intermediate portion is formed. That is, a manhole 8 for entering and exiting is provided on the side wall. In addition, 6 is a ventilation pipe,
7 is a manhole at the top of the upper and lower tanks, and 14 is a take-out pipe. However, steel tanks with resin lining on the inside,
Inferior in corrosion resistance and high maintenance cost,
Inexpensive fiber reinforced plastic (FR
P) It is desired to provide a multi-stage tower tank composed entirely of tanks.

[0004] In order to meet the above demand, when stacking and producing a multi-stage FRP tower tank in the same manner as a steel tank, a cylindrical intermediate space serving as a working space formed between the upper and lower tanks. When a hole (notch) for attaching a manhole structure for an operator to enter / exit the portion is provided in the cylindrical structure portion, that is, the side wall portion of the cylindrical intermediate portion, the manhole insertion hole is cut. Since the strength of the side wall portion of the cylindrical intermediate portion is reduced by the amount of the lack, and the entire multi-stage column becomes unstable, consideration must be given to reinforcing the strength of the side wall portion, and In contrast to the case of joining the steel side wall portion and the manhole structure that can be joined by welding, it is also an issue to secure sufficient attachment strength at the attachment portion of the manhole structure.

As a method of providing a manhole on the side wall of the cylindrical intermediate portion of the above-mentioned FRP multi-stage tower tank, a manhole structure 12 having a structure as shown in FIG. An annular rib 10 having the shape shown in FIG. 3 is inserted around the manhole structure mounting portion on the outer wall side.
The manhole structure 12 is fixed by fixing the manhole structure 12 or as shown in FIG. 4, the annular rib 11 protruding into the internal space is arranged on the inner wall side of the cylindrical intermediate portion, and the manhole structure 13 is attached thereto. A method of bonding and fixing is adopted.

However, in these methods, there is a problem in cost due to the necessity of using a separately formed rib, and when a rib is provided inside the cylindrical intermediate portion, the working space becomes narrow. Therefore, there is a problem that workability is impaired. Further, if the ribs are used to reinforce a region in which the strength of the side wall portion can be reduced due to the cut-out of the side wall portion due to the installation of the manhole, it is necessary to increase the size of the rib. In terms of surface problems.

[0007]

SUMMARY OF THE INVENTION Therefore, the present invention
On the side wall of the cylindrical middle part of the upper and lower tanks of the RP multi-stage tower tank,
A manhole having a structure that does not cause a reduction in strength of the entire cylindrical intermediate portion, has sufficient mounting strength, and can secure a sufficient working space in the cylindrical intermediate portion, is simple and workable. It is an object of the present invention to provide an inexpensive manufacturing method that can be provided by a good method, and a multi-stage FRP column tank provided with manholes having sufficient mounting strength mounted by the method.

[0008]

SUMMARY OF THE INVENTION The inventors of the present invention have repeatedly conducted research and development on an attachment method which can replace a costly attachment method of providing a rib at an attachment point of a manhole. Further, it has been found that by covering a certain area around the area with the FRP lamination, a manhole having the same mounting strength as that of mounting the rib can be formed. Also,
It has also been found that by making the thickness of the FRP laminate not less than a certain thickness, it is possible to compensate for the decrease in the strength of the side wall of the cylindrical intermediate portion caused by the notch serving as the hole for manhole. As described above, the present invention relates to an FRP multi-stage column having a manhole having a sufficient mounting strength and compensating for a decrease in the side wall strength of the cylindrical intermediate portion due to the mounting of the manhole structure. The invention includes the following inventions.

(1) A multi-stage fiber tank made of fiber reinforced plastic having a tower tank portion consisting of a cylindrical intermediate portion provided with an upper tank and a manhole and a lower tank, wherein the cylindrical intermediate portion is provided on a side wall thereof. The area from the trunk of the square or cylindrical manhole structure placed in the drilled insertion hole, through the manhole structure insertion hole to the cylindrical middle side wall is thermoset for fiber reinforced plastic. The structure is coated with the composition, cured with a resin, and adhered and fixed, and the coating region on the cylindrical intermediate side wall with the coating layer is aligned with the rectangular cylindrical manhole starting from the manhole structure insertion hole. 1.0 to the distance from the center point of the opening to both the vertical and horizontal sides.
It is an area equivalent to 1.5 times the distance, and in the case of a cylindrical manhole, the radius of the opening at the opening is 1.0 to 1.0.
This is a region corresponding to a distance of 1.5 times, and the thickness of the coating layer in the coating region is 1.1 of the thickness of the cylindrical intermediate portion side wall.
A multi-stage tower tank made of fiber reinforced plastic, characterized in that the ratio is 5 to 2.5 times.

[0010] (2) The tower tank portion comprising the upper tank, a tubular intermediate portion having a manhole, and a lower tank is a lower cylinder integrally formed with the lower part of the body of the upper tank made of fiber reinforced plastic. The tip of the tubular structure is joined to the tip of the upper tubular structure integrally formed with the upper part of the body of the lower tank made of fiber-reinforced plastic, and a cylinder is formed between the upper tank and the lower tank. The multistage tower tank made of fiber-reinforced plastic according to item (1), characterized in that the tower tank section is formed by forming a shape-like intermediate portion and then attaching the manhole structure.

(3) The tip of the lower tubular structure formed integrally with the lower part of the body of the upper tank made of fiber-reinforced plastic, and the upper part of the body of the lower tank made of fiber-reinforced plastic integrally. Forming a tower section having a tubular intermediate portion between the upper tank and the lower tank by joining the tip portion of the formed upper tubular structure to a structure for manholes on a side wall of the tubular intermediate section; A step of drilling a body insertion hole to insert a rectangular cylindrical or cylindrical manhole structure and temporarily fixing the same, and a step of inserting the manhole structure through a manhole structure insertion hole from above the trunk of the manhole structure. A coating layer made of a thermosetting composition for fiber-reinforced plastic is formed in a region extending over the side wall of the intermediate portion. At this time, on the side wall of the cylindrical intermediate portion, a rectangular tube In the case of a shaped manhole, it is vertical from the center point of the opening. 1.0 to 1.5 of the distance to both sides
For a region up to a distance equivalent to twice, and in the case of a cylindrical manhole, a radius of 1.0 to
Forming a coating layer having a thickness of 1.5 to 2.5 times the thickness of the intermediate side wall for a region up to 1.5 times the distance,
And a step of bonding and fixing the manhole structure to the side wall of the tubular intermediate portion by curing the thermosetting resin in the coating layer. .

(4) The step of joining the distal end of the lower tubular structure of the upper tank to the distal end of the upper tubular structure of the lower tank may include the step of joining one distal end of the tubular structure of both tanks. This step is a step of joining the two end portions as an annular spigot structure, joining the other end portions as a socket structure composed of an annular groove, covering the inner and outer surfaces of the joined portion with a thermosetting composition for fiber-reinforced plastic, and curing the resin. (3) The method for producing a multi-stage tower tank made of fiber-reinforced plastic according to (3).

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A multistage column tank 1 made of FRP according to the present invention.
Although there is no limitation on the number of stacking stages of the tank, it is usually a two-stage tower tank as shown in FIG. 1, and in a typical example, a manhole 8 capable of entering and leaving inside is provided between upper and lower tanks. It has a tubular intermediate part 4. The tubular intermediate portion 4 is a space formed by joining the tip of the lower tubular structure 2 ′ of the upper tank 2 to the tip of the upper tubular structure 3 ′ of the lower tank 3. Is preferred.

As described above, the cylindrical intermediate portion 4 is
Of the lower cylindrical structure 2 'and the upper cylindrical structure 3' of the lower tank 3
The manhole 8 provided on the side wall portion of the formed cylindrical intermediate portion 4 is formed by joining the lower cylindrical structure portion 2 ′ of the upper tank 2 where the manhole is provided. It may be attached to the upper tubular structure 3 ′ of the lower tank 3 in advance, or may be joined to the lower tubular structure 2 ′ of the upper tank 2 and the upper tubular structure 3 ′ of the lower tank 3. After the cylindrical intermediate portion 4 is formed, an insertion hole 8 ′ may be formed in a side wall portion of the space portion, and then the manhole member may be inserted and fixed.

[0015] In the method of the present invention, the manhole mounting operation using the thermosetting composition for FRP molding is performed by inserting an insertion hole formed in a cylindrical body portion of a cylindrical intermediate portion of a multi-stage tower having the manhole installation position. The manhole member is inserted into the manhole body, and the manhole body is covered with the insertion hole from the top of the manhole body so as to cover a predetermined area on the outer wall of the cylindrical body portion.
This is an operation of laminating the thermosetting composition for RP molding and repeating the operation of curing the resin to laminate the FRP layer to a predetermined thickness. The operation of forming such a laminated FRP layer is not an operation requiring special skill, and is therefore an operation capable of reliably forming a manhole portion having a predetermined mounting strength.

In the above operation, at the same time as forming a manhole portion having a desired mounting strength, the present invention reinforces the strength of the entire cylindrical intermediate portion by forming a similar laminated FRP layer over a predetermined region. Is also intended. For the purpose of reinforcing the side wall strength of such a tubular intermediate portion, the FRP formed by the method of the present invention is used.
The area of the covering area by the lamination and the thickness of the covering layer are different from those of the hole in the side wall which is cut out from the manhole member insertion hole at the side wall portion of the intermediate cylindrical space so as to correspond to the diameter of the manhole member. It is determined by the size and the thickness of the side wall (trunk) of the cut-out cylindrical intermediate portion.

That is, the region covering the side wall surface of the cylindrical intermediate portion is substantially the same regardless of whether the manhole member is cylindrical or rectangular, and as shown in FIG.
Starting from the position of the manhole insertion hole 8 ′, in the case of a rectangular cylindrical manhole, the distances (a) and (b) from the center point to both the vertical and horizontal sides are (n × a) and (n × b). In the case of a circular manhole, as shown in FIG.
This is the area 9 in c). In the present invention, in any case, it is a distance region where n = 1.0 to 1.5.
In each case, the thickness of the coating layer in the coating region 9 on the side wall of the cylindrical intermediate portion is 1.5 to 2.
5 times. It is not necessary to further increase the manhole attachment strength by extending the coating layer to a region where the numerical value n for determining the coating region 9 exceeds 1.5. If the value n is less than 1.0, the mounting strength may be insufficient, which is not preferable.

The thickness of the coating layer that covers the periphery of the manhole attachment point is a thickness that can guarantee a reduction in strength caused by the side wall portion cut out for manhole installation. Preferably it is 1.5 to 2.5 times. Although the strength can be further improved by laminating a coating layer having a thickness more than 2.5 times, even if the FRP lamination exceeds the required strength, an effect corresponding to the increase in cost cannot be expected. On the other hand, if it is less than 1.5 times, a desired strength may not be secured, which is not preferable.

According to the above manhole mounting method, the notch provided for installing the manhole in the space between the tanks of the multi-stage tower tank can be reinforced by appropriate means, and the workability between the tanks is hindered. It is possible to construct the intermediate section between tanks at low cost and having the same strength as the main body against external force such as earthquake or own weight at low cost.

[0020]

EXAMPLE A two-stage tower tank having the dimensions shown in Table 1 was manufactured for testing in accordance with a method for manufacturing a normal FRP tank. As shown in Table 2, with respect to manholes installed in the trunk between the tanks (cylindrical intermediate part), a tower tank in which the coating region and the coating thickness by the FRP overlay were changed was manufactured and subjected to a test. In addition, the thickness of the body was set to half the normal thickness so that the manhole between the tanks would be broken during the vibration test.

In the shake test, the horizontal seismic intensity of the shaker was gradually increased, and the evaluation was made based on the ratio of the horizontal seismic intensity at the time of the occurrence of the rupture in the manhole between the tanks. That is, the breaking load with respect to the horizontal seismic intensity of the body between the tanks when no manhole was installed between the tanks was set to 1, and the ratio of the test breaking seismic intensity of the cylindrical intermediate portion where the manhole was installed to each tank was calculated. The results are shown in FIG. As a result of the test shown in FIG. 5, in the case where this ratio (vertical axis) was a value of 1.0 or less, all the manhole portions were broken. Based on the result that the ratio (vertical axis) is 0.9 or more, the range and the coating thickness of the coating region of the FRP coating portion of the present invention were set from the results shown in FIG.

In the case where a flat cylindrical manhole having a diameter of 600 mm is installed in the body between the tanks, in the present invention, the reinforcing wall thickness ratio is set to 1.5, the opening reinforcing dimension area is made equal to the manhole radius, and the manhole is formed. For comparison, the manhole was attached by a method of reinforcing the inside of the manhole with a rib for comparison, and the production cost (material cost and production time) of the two at the present time was compared with that of the attachment method of the present invention by one. As a result, the material cost of the rib reinforcement method was 1.7 and the production time was 2.3.

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

As described above, the FRP in the manhole-installed portion of the body between the tanks (middle portion of the cylinder) of the present invention as described above.
It is clear that selecting the numerical range of the coating area and the numerical range of the thickness of the coating layer shows excellent results in the reinforcing effect of the manhole attachment portion of the trunk between the tanks.

[Brief description of the drawings]

FIG. 1 is a side view of a two-stage column tank of the present invention.

FIG. 2 is a diagram showing an arrangement region of an FRP reinforcing coating layer around a square cylindrical and cylindrical manhole.

FIG. 3 is a conventional rib reinforcement diagram.

FIG. 4 is a conventional rib reinforcement diagram.

FIG. 5 is a diagram showing a relationship between a coating layer region and a coating layer thickness in a cylindrical intermediate portion and a breaking strength.

[Explanation of symbols]

1: multi-stage tower tank, 2: upper tank, 2 ': lower tubular structure,
3: lower tank, 3 ': upper tubular structure part, 4: tubular middle part,
5: joint, 6: vent pipe, 7: manhole, 8, 12:
Manhole in the middle of the tube, 8 ': hole for insertion, 9: FRP
Covering area, 10: external rib, 11: internal rib, 13: flat manhole, 14: extraction pipe

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hiromichi Mochizuki 90 Maeda, Fuji City, Shizuoka Prefecture Fuji Chemical Co., Ltd.F-term (reference) 3E070 AA03 AB10 BF01 DA08 GB04 GB14 KA11 KB02 KB06 KC02 PA04 PA06 RA02 RA03 TA06 VA01

Claims (4)

[Claims] 1. A fiber-reinforced plastic multi-stage tower tank having a tower tank section comprising an upper tank, a cylindrical intermediate section having a manhole, and a lower tank, wherein the cylindrical intermediate section is formed on a side wall thereof. The thermosetting composition for fiber reinforced plastic covers the area from the body of the rectangular or cylindrical manhole structure placed in the provided insertion hole to the middle intermediate wall through the manhole structure insertion hole. In a rectangular tube-shaped manhole, the covering region on the cylindrical intermediate side wall by the covering layer is a manhole structure insertion hole as a base point. Is 1.0 to 1.0 of the distance from the center point in the opening to both the vertical and horizontal sides.
It is an area equivalent to 1.5 times the distance, and in the case of a cylindrical manhole, the radius of the opening at the opening is 1.0 to 1.0.
This is a region corresponding to a distance of 1.5 times, and the thickness of the coating layer in the coating region is 1.1 of the thickness of the cylindrical intermediate portion side wall.
A multi-stage tower tank made of fiber reinforced plastic, characterized in that the ratio is 5 to 2.5 times. 2. A tower tank portion comprising an upper tank, a tubular intermediate portion having a manhole, and a lower tank, is a lower cylindrical member integrally formed with a lower portion of a body of a fiber reinforced plastic upper tank. The distal end of the structural part is joined to the distal end of the upper tubular structure that is integrally formed with the upper part of the body of the lower tank made of fiber-reinforced plastic, and a cylindrical shape is formed between the upper tank and the lower tank. Forming an intermediate portion, and then a tower tank portion formed by attaching the manhole structure,
The fiber-reinforced plastic multistage tower tank according to claim 1. 3. A tip portion of a lower tubular structure portion integrally formed with a lower portion of a body portion of a fiber-reinforced plastic upper tank, and integrally formed with an upper portion of a body portion of the fiber-reinforced plastic lower tank. Forming a tower tank portion having a cylindrical intermediate portion between the upper tank and the lower tank by joining the tip portion of the upper cylindrical structure portion, and a manhole structure on a side wall of the cylindrical intermediate portion. Drill an insertion hole and insert a rectangular or cylindrical manhole structure,
Temporarily fixing, forming a coating layer of a thermosetting composition for fiber-reinforced plastic on a region extending from a body portion of the manhole structure to a side wall of the tubular intermediate portion through a manhole structure insertion hole. At that time, on the side wall of the cylindrical intermediate portion, starting from the insertion hole of the structure for manhole as a base point, in the case of a rectangular cylindrical manhole, the distance from the center point of the opening to both the vertical and horizontal sides is 1.0 to 1.0. For an area up to a distance equivalent to 1.5 times, and for a cylindrical manhole, an area up to a distance of 1.0 to 1.5 times the radius at the opening,
Forming a coating layer having a thickness of 1.5 to 2.5 times the thickness of the side wall of the intermediate portion; and then curing the manhole structure by curing the thermosetting resin in the coating layer. A method of manufacturing a multi-stage tower tank made of fiber-reinforced plastic, comprising a step of bonding and fixing to a side wall. 4. The step of joining the tip of the lower tubular structure of the upper tank and the tip of the upper tubular structure of the lower tank,
One end of the cylindrical structure of both tanks is an annular spigot structure, the other end is a socket structure consisting of an annular groove, and both ends are joined, and the inner and outer surfaces of the joint are thermoset for fiber reinforced plastic 4. The method for producing a fiber-reinforced plastic multi-stage tower tank according to claim 3, wherein the step is a step of coating with a conductive composition and curing the resin.