JP3983044B2 - Fluorine resin lining tank - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of a fluororesin lining tank suitable for use in a tank for storing a chemical solution or the like.
[0002]
[Prior art]
Conventionally, chemical tanks that handle corrosive liquids such as various chemicals and solvents are markedly superior to other synthetic resins in terms of heat resistance, chemical resistance, purity, etc. A fluororesin lining tank provided as a fluororesin lining material having the above has been widely used.
[0003]
In the fluororesin lining tank, a lining sheet in which a glass cloth is welded on one side to a metal outer can body divided into a cylindrical body and a lid that covers the cylinder mouth, or a lining sheet that is chemically etched on one side A-type type (can body split type, lining sheet adhesive type) in which the body portion and the lid portion are fixed with bolts via a flange, and molded in a cylindrical bag shape in advance by rotational molding or the like Cover the fluororesin lining material from the outside with the divided metal outer can body, and the lining material and the metal outer can body will not be bonded, and the connecting part of the divided body part and lid part is integrated by welding fixing There are B type types (can body integrated type, lining sheet non-adhesive type).
[0004]
[Problems to be solved by the invention]
In the A-type fluororesin lining tank, it is fixed with bolts through flanges provided on the body and the lid, respectively, but the cost of the flange is very high, which only increases the cost of the outer can body. In addition, it takes time and effort to bond the lining sheet to the inside of the metal outer can body (body portion and lid portion), which also increases the cost.
Moreover, although it is necessary to integrate the joint part of the lining sheets pasted with the adhesive by welding, the welded part is inferior in mechanical strength as compared with the lining sheet part which is the base material.
[0005]
Therefore, when a large stress is applied to the lining sheet for some reason, there is a possibility that a crack or a pinhole may occur at the welded portion. In addition, foreign matter or the like may be mixed in the welded part in the welding process, and this foreign matter may cause cracks or pinholes, or may cause a decrease in the purity unique to the fluororesin.
[0006]
On the other hand, in the B-type fluororesin lining tank, the outer periphery of the cylindrical bag-shaped lining material is covered with a metal outer can divided into a body portion and a lid portion, and the divided body portion and lid portion are separated. The connecting part is integrated by welding.
Therefore, the B-type does not require the flange portion in the A-type, and can eliminate the bonding of the lining sheet material and the welding of the lining sheets, thereby reducing the cost.
However, when welding the connecting portion of the body portion and the lid portion divided on the outside of the lining material, the lining sheet material may be damaged or melted by the heat.
[0007]
Accordingly, a fluororesin lining tank having a structure shown in FIG. 4 has been proposed as a solution to the problem of the B type.
In FIG. 4, 1 is a fluororesin lining material formed into a cylindrical bag shape, 2 is a cylindrical body forming a metal outer can covering the lining material, and 2a is a lower cylinder opening of the cylindrical body. The extended cylindrical leg portion 2b is a concentric cap-shaped lid portion that can be inserted into the cylindrical leg portion 2a. The cap-shaped lid portion 2b is inserted into the cylindrical leg portion 2a. After that, the entire circumference of the lower end of both is fixed by welding and integrated. 2c is the weld.
[0008]
According to the above structure, since the welded portion connecting the body portion and the lid portion of the can body is separated from the lining sheet, there is no possibility that the lining material is damaged or melted by welding heat.
However, in the structure described above, the constituent material of the metal outer can body increases, which increases the number of processing steps, which increases the cost.
[0009]
In addition, the tank (pressure vessel) structure used at a certain capacity and above a certain pressure is stipulated by the Labor Safety and Health Law of the Labor Bureau of the Ministry of Health, Labor and Welfare, and the outer can of the lining tank is no exception. Fluoropolymer lining tanks are often used in such a way that chemicals are stored in the tank and discharged to the outside by nitrogen pressurization, and most of them correspond to Type 2 pressure vessels of the Industrial Safety and Health Act. This type 2 pressure vessel corresponds to a tank having a tank capacity of 40 L or more and a working pressure of 0.2 MPa or more, and must be manufactured in a structure defined in the standard and pass the inspection of a specific engine.
[0010]
In the structure of the conventional B type tank described above, the welded portion between the body and the lid of the outer can body is located as shown in FIG. 4, and when pressure is applied to the inside of the tank, the pressure is applied to this portion. Is easy to concentrate and deform easily. Therefore, it is insufficient as a withstand voltage structure. In addition, since this structure is not a structure defined in the standard, a conventional A-type lining tank is used when it is a second type pressure vessel.
[0011]
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a fluororesin lining tank that is easy to manufacture and inexpensive.
[0012]
[Means for Solving the Problems]
The present invention is a fluororesin lining tank configured by covering a fluororesin lining material molded into a required shape with a segmented metal exterior can body, where the segmented portions of the metal exterior can body are welded to each other; A heat insulating material is provided between the lining material and the heat insulating material is a laminate of a polytetrafluoroethylene sheet and a polyimide sheet, and the polytetrafluoroethylene sheet side of the laminate is the metal exterior. that it places the can body side is a gist.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
As a preferred embodiment of the present invention, as shown in FIG. 1 to FIG. 3, in a fluororesin lining tank configured by covering a fluororesin lining material A previously formed in a cylindrical bag shape with a metal outer can body B, The metal outer can body B uses a can body that is divided into a cylindrical body b ₁ and bowl-shaped lids b ₂ and b ₃ that respectively close both the mouths of the cylinder, and the upper lid b ₂ is previously a body. part b ₁ to butt leave welded, lid b ₃ of the lower and freely fitted to the trunk portion b _1, barrel b the tubular bag-like lining material before fitting the lid b _{3 In addition to} being inserted into ₁ , the connecting portion is welded in a state where a heat insulating material C is disposed between the connecting portion by fitting the body portion b ₁ and the lid portion b ₃ and the lining material A. Thus, the lid b ₃ is integrated with the body b ₁ . b ₄ is a weld.
[0014]
The lining material A is preferably a fluororesin such as PFA or PTFE, and can be formed into a cylindrical bag shape by an integral molding method such as a rotational molding method, a blow molding method, or an isostatic molding method.
[0015]
The heat insulating material C arranged between the lining material and the connecting portion of the divided can bodies absorbs or insulates the welding heat when the divided can bodies are welded to each other so that the lining material is not damaged. Therefore, an organic material or an inorganic material having a melting point of 200 ° C. or higher is used.
[0016]
As the organic material having a melting point of 200 ° C. or higher, engineering plastics such as fluororesins such as PTFE and PFA, polyimide resins, polyether ether ketone (PEEK), polyphenylene sulfide (PPS), and polyetherimide (PEI) can be used. PTFE is desirable because it is heat resistant, flame retardant, and has a high melting point. Further, the above-mentioned sheets may be appropriately overlapped. Among them, the lining material in which the polyimide resin and PTFE are overlapped particularly in order not to fuse the lining material made of fluororesin and the heat insulating material PTFE. preferable.
[0017]
On the other hand, glass fibers, rock wool, asbestos, and the like can be used as the inorganic material, but a glass fiber mat or a cloth-like one is particularly preferable in terms of handling.
Moreover, as thickness of a heat insulating material, although it changes with kinds of material, the thickness which absorbs the heat | fever amount in the case of welding or insulates is required. For example, when fluororesin (PTFE) is used as the heat insulating material, it is desirable that the thickness be 0.3 mm or more.
[0018]
In FIG. 1, D is a metal support that supports the tank, and this support is welded and fixed to the body b ₁ in advance before the lining material A is put into the metal outer can body B.
[0019]
According to the configuration of the fluororesin lining tank of the present invention, since the heat insulating material is interposed between the lining material and the connecting portion of the divided metal outer can body, it is convenient to perform welding at the lining tank manufacturing site. In addition, the number of components of the metal outer can body can be reduced and labor can be reduced, and the manufacturing cost can be greatly reduced.
[0020]
【Example】
In the fluororesin lining tank shown in FIGS. 1 to 3, a metal outer can body covering the lining material A is used as the lining material A by using a PFA molded in a cylindrical bag shape by a rotational molding method. B uses a barrel b ₁ , an upper lid b ₂ , and a lower lid b ₃ formed of a metal plate (SUS304) having a thickness of 4.0 mm, and the upper lid b ₂ is a barrel b. ₁ is previously integrated by butt welding and fixing, and the cylindrical bag-shaped lining material A is inserted and disposed therein, and the lid portion b ₃ is fitted between the body portion b ₁ and the connecting portion between the lining material and the lining material. Then, a strip-shaped heat insulating material C made by integrating PTFE with a thickness of 0.5 mm and polyimide with a thickness of 0.125 mm with a polyimide-based adhesive tape is bonded and fixed so that the PTFE faces the metal tube side, and then the lid trunk portion _{b 1} of part _{b 3} Welding the connecting portion due to alignment fit, to constitute a lining tank by fixing the lid portion b ₃ to the trunk portion b ₁ by welding.
[0021]
When the connecting part between the body part b ₁ and the lid part b ₃ is welded, since the heat insulating material C is provided between the connecting part and the lining material A, the heat insulating material heats even when welding is performed. By absorbing and insulating, it was confirmed that the temperature rise of the lining material was suppressed and the lining material was prevented from being damaged.
Moreover, when the lining material side of the heat insulating material C was made into the polyimide layer, it was recognized that it can prevent that the lining material and PTFE of a heat insulating material melt | fuse at the time of welding.
[0022]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to obtain a fluororesin lining tank that is simple to manufacture and inexpensive.
[Brief description of the drawings]
FIG. 1 is a front view of a fluororesin lining tank showing an embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of a portion where a divided body portion and a lower lid portion are connected by welding.
FIG. 3 is a schematic configuration diagram of the weld connection portion.
FIG. 4 is a cross-sectional view of a conventional fluororesin lining tank.
[Explanation of symbols]
1 cylinder bag-like molded into the lining material 2 metal outer can body 2a cylindrical barrel extension leg 2b galea lid 2c weld A tubular bag shape molded lining material B metal outer can body b ₁ tubular in Body part b ₂ Upper cover part b ₃ Lower cover part b ₄ Welding part C Heat insulating material D Metal support leg

Claims (1)

A fluororesin lining tank configured by covering a fluororesin lining material formed into a required shape with a divided metal outer can body, the portion where the divided parts of the metal outer can body are welded to each other, and the lining material A heat insulating material is provided between the polytetrafluoroethylene sheet and the polyimide sheet, and the polytetrafluoroethylene sheet side of the laminated body is disposed on the metal exterior can body side. fluororesin lining tank, wherein to Rukoto.

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