JPH0641318B2 - Lining method for the inner surface of the tank - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for lining the inner surface of a tank that stores a high-purity chemical solution, and more specifically, a nozzle that projects inward from the wall surface of the tank. The present invention relates to a method for lining the inner surface of a tank having a portion.

(Prior art) For tanks that store high-purity chemicals, the inner surface of the tank is lined with a lining material that has excellent chemical resistance and corrosion resistance, which prevents corrosion of the tank by chemicals. It is known that the durability is remarkably improved. For example, JP-A-55-67409 discloses a method of lining an inner surface of a nozzle portion provided so as to project from a wall surface of a tank. . In the lining method disclosed in the publication, an insertion tube to be inserted into the nozzle portion is manufactured in advance so that the insertion tube is in contact with the inner surface of the nozzle portion, and the insertion tube is inserted into the nozzle portion to form a nozzle. After fixing the inner peripheral surface of the portion and the outer peripheral surface of the insertion tube with an adhesive or a joint material, the lining material on the inner surface of the tank is joined.

(Problems to be Solved by the Invention) In the method disclosed in the publication, since the inner surface of the nozzle portion protruding to the outside of the tank is lined, there is a case where the screw portion is formed on the inner surface of the nozzle portion. As described above, when it is not necessary to coat the inner surface of the nozzle portion, it cannot be carried out.

In particular, when the nozzle portion having the threaded portion formed on the inner surface projects inward from the tank wall surface, the method disclosed in the above publication cannot be carried out, and normally only the inner surface of the tank wall surface is By lining with a lining sheet, the nozzle portion is not lined and is projected from the lining sheet. For this reason, the space between the nozzle portion and the lining sheet cannot be reliably sealed in a liquid-tight state, and the liquid that enters through the gap between the two enters the tank wall surface and the lining material, There is a risk of peeling the lining material from the wall of the tank.

The present invention is to solve the above-mentioned conventional problems, and an object thereof is a method for lining a tank inner surface capable of stably lining the inner surface of a tank provided with a nozzle portion protruding inward from a tank wall surface for a long period of time. To provide.

(Means for Solving the Problem) A method of lining a tank inner surface according to the present invention includes a step of forming a screw portion on an outer peripheral surface of a nozzle portion projecting inward from a tank wall surface, and a step of forming an inner surface of the tank wall surface on the nozzle portion. Except for the step of lining with a predetermined lining material, a cylindrical member made of a predetermined lining material formed on the inner peripheral surface of a threaded portion screwed to the threaded portion formed on the outer peripheral surface of the nozzle portion,
The method includes a step of screw-engaging with a threaded portion of the nozzle portion to cover the nozzle portion, and a step of welding a cylindrical member that covers the nozzle portion and a lining material that lines the inner surface of the tank wall surface. The purpose is achieved.

(Example) Hereinafter, the present invention will be described with reference to Examples.

The lining method of the present invention is, for example, as shown in FIG.
It is carried out when lining the inner surface of the tank provided with the metal nozzle portion 20 penetrating therethrough. The nozzle unit 20 is
It is connected to the wall surface of the tank by welding, and thus is in a state of protruding inward and outward from the wall surface 10 of the tank. The nozzle portion 20 has a screw portion 22 formed at a portion protruding outward from the tank wall surface 10.

In the method of the present invention, first, the tank wall surface 10 in the nozzle portion 20 is
A screw part (21) is formed on the outer peripheral surface of the part projecting inwardly from. Then, a predetermined lining material 30 is adhered to the inner surface of the tank wall surface 10 via the adhesive layer 60, and the lining material 30
The inner surface of the tank wall surface 10 is lined by. On the other hand, as shown in FIG. 1, a lining material for lining the tank wall surface 10 with a cylindrical member 40 having an inner peripheral surface formed with a threaded portion 41 screwed to a threaded portion 21 formed on the outer peripheral surface of the nozzle portion 20.
Pre-manufactured with a lining material similar to 30. The cylindrical member 40 is in a state in which one end surface is formed with an opening 42 equal to the inner diameter of the nozzle 20 and the portion other than the opening 42 is closed.

When the inner surface of the tank wall surface 10 is lined with the lining material 30, a packing made of an elastic material such as rubber is attached to the tip surface of the portion of the nozzle portion 20 projecting into the tank wall surface 10.
In a state where 50 is abutted, the screw portion 21 formed on the outer peripheral surface of the nozzle portion 20 is screwed to the screw portion 41 formed on the inner peripheral surface of the cylindrical member 40 to form the nozzle portion. The cylindrical member 40 covers the portion of the tank 20 that protrudes into the tank wall surface 10. As a result, the end surface of the cylindrical member 40 opposite to the end surface on which the opening 42 is formed is in contact with the lining material 30 that covers the inner surface of the tank wall surface 10. At this time, the tip of the nozzle portion 20 protruding into the tank and the cylindrical member
The packing 50 interposed between the one end face of 40 and the one end face is pressed by both to seal the both in a liquid-tight manner.

After that, the abutting portions of the cylindrical member 40 and the lining material 30 are welded and connected. As a result, the lining material 30 and the cylindrical member 40 are connected in a liquid-tight manner, and there is no risk that the liquid contained in the tank will enter from between the lining member 30 and the cylindrical member 50. In addition, since the packing 50 also ensures a liquid-tight state between the cylindrical member 40 and the portion of the nozzle portion 20 that protrudes inward from the tank wall surface 10, it is accommodated in the tank between them. There is no risk of liquid ingress or permeation.

In the method of the present invention, as the lining material 30 for lining the inner surface of the tank wall surface 10, PTFE (tetrafluoroethylene resin), FEP (tetrafluoroethylene / hexafluoropropylene copolymer), PFA (tetrafluoroethylene. Sheets of a fluororesin such as a perfluoroalkoxyl resin copolymer) or PVDF (vinylidene fluoride resin) or a vinyl chloride resin, a thermoplastic resin such as hard polyethylene or polypropylene are used. The thickness of the sheet is preferably about 0.5 mm to 5.0 mm. If the thickness of the sheet is 0.5 mm or less, the anticorrosive effect may not be exhibited, and if it is 5.0 mm or more, it becomes impossible to attach the sheet to the inner surface of the tank wall surface 10 when lining the inner surface of the tank wall surface 10. There is a risk. Further, a sheet backed with glass cloth or polyester cloth can also be preferably used.

The screw portion 21 formed on the outer peripheral surface of the nozzle portion 20 protruding inward from the tank wall surface 10 is a normal pipe straight screw or a taper screw.

The cylindrical member 40 is preferably made of a lining material made of the same material as the lining material 30. When different materials are used, there is a risk of a joint failure when welding the cylindrical member 40 and the lining material 30 that lines the inner surface of the tank wall surface 10. The cylindrical member 40 is machined by a lathe or the like using a thermoplastic resin rod. The wall thickness of the cylindrical member 40 is equal to or larger than the thickness of the lining material 30, and usually 3 to 10 m.
About m is suitable. Cylindrical member 4 against which packing 50 is pressed
The thickness of the end surface of 0 is required to be such that creep deformation due to the tightening force does not occur. For example, in the case of PVDF, it is about 5 to 10 mm.

As the packing 50, elastic and corrosion-resistant rubber is used, and fluororubber, silicon rubber, nitrile rubber and the like are preferable. The thickness of the packing is preferably about 1 to 3 mm.

The packing 50 interposed between the tip of the nozzle portion 20 and the end surface of the cylindrical member 40 has an initial thickness of 30 to 90 due to compressive deformation.
It is tightened so that it becomes about%.

For welding the cylindrical member 40 and the lining material 30, a hot-air type welding machine used for welding vinyl chloride resin or the like is used. The hot air temperature during welding is 10 higher than the melting point of the thermoplastic resin.
It is set to a high temperature of about 0 to 200 ° C, and in the case of PVDF,
A temperature of about 270 to 370 ° C is suitable.

As the adhesive layer 60 for adhering the inner surface of the tank wall surface 10 and the lining material 30, an adhesive used for sheet lining is used, and a rubber-based, epoxy-based, acrylic-based or urethane-based adhesive is suitable. . Next, an experimental example of the method of the present invention will be shown.

[Experimental Example 1] A steel plate with a thickness of 9 mm (material SS41) is 300 mm x
Cut to a size of 300 mm, and in the center of the steel plate, diameter 28 m
m through holes were formed. Then, in the through hole, a nominal diameter of 3 /
A stainless steel pipe (material SUS316L) having a length of 4 inches (outer diameter 27.3 mm) and a length of 40 mm is projected 23 mm from the surface of the steel sheet to be lined, and is welded to the surface opposite to the surface to be lined. Part and

Next, a parallel pipe screw (P
S3 / 4) is formed on the surface of the steel sheet to be lined,
Epoxy adhesive (trade name "Esdyne # 3100",
After applying Sekisui Chemical Co., Ltd., PV with a thickness of 2 mm
A DF lining sheet (trade name "Kohran ESP", manufactured by Showa Denko KK) was attached.

After that, by lathing a commercially available PVDF rod with a diameter of 40 mm, a PVD rod with a length of 29 mm that was previously manufactured
The cylindrical member made of F was screw-connected to the nozzle portion with a packing made of fluororubber having a thickness of 2 mm (trade name "Viton", manufactured by DuPont) interposed therebetween. The cylindrical member has a parallel thread (PS3 / 4) for a pipe in the threaded portion, and the wall thickness of the pipe end face with which the packing abuts is 7 mm. The cylindrical member was screwed to the nozzle portion until the end surface of the cylindrical member came into contact with the lining material for lining the steel plate. At this time, the packing became 50% (1 mm) of the initial thickness.

In such a state, the abutting portion of the cylindrical member and the lining material was welded. The welding process was performed using a hot air type welding machine for vinyl chloride resin and a commercially available PVDF welding rod. The hot air temperature of the welding machine was 320 ° C.

Thus, a test piece was manufactured, and the test piece was subjected to a penetration test from the lining surface by a water penetration acceleration tester (blister tester) using a temperature gradient. Regarding the test conditions, the lining surface and the nozzle portion were immersed in water at 100 ° C, and the steel plate surface on the side opposite to the lining surface was maintained at 30 ° C.

As a result, there was no abnormality for 1500 hours.

[Experimental Example 2] A commercially available glass cloth backed PTFE sheet having a thickness of 2 mm was used as a lining sheet for lining a steel sheet, and a commercially available PTFE rod having a diameter of 40 mm was used as a material for the cylindrical member. A commercially available PFA welding rod was used as a welding rod for welding the sheet. Further, the hot air temperature during welding was set to 410 ° C. Other conditions are the same as in Experimental Example 1. As a result of the penetration test, there was no abnormality for 500 hours.

[Comparative Example] In Experimental Example 1, only the steel plate surface of the test piece was lined under the same conditions, and the nozzle surface was not lined. The lining material on the surface of the steel sheet and the nozzle portion were lined so that no gap was formed. When the same penetration test as in Experimental Example 1 was conducted, water penetrated through the gap between the nozzle portion and the lining material in 20 hours, and 50% of the lining material was peeled off.

(Effect of the Invention) The tank inner surface lining method of the present invention is
The lining material for lining the inner wall surface of the tank and the cylindrical member covering the nozzle portion are made liquid-tight by welding, and between the cylindrical member and the nozzle portion are made liquid-tight by packing, Liquid is reliably prevented from entering between the lining material and the wall surface of the tank, and the lining material is prevented from being separated from the wall surface. As a result, the inner surface of the tank wall surface where the nozzle portion projects inward can be reliably lined with the nozzle portion, and the inner surface of the tank wall surface can be protected for a long period of time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a lining structure of an inner surface of a tank formed by carrying out the method of the present invention, and FIG. 2 is a cross-sectional view of the tank showing an implementation process thereof. 10 …… tank wall, 20 …… nozzle part, 21,22 …… screw part, 30 …… lining material, 40 …… cylindrical member, 41 …… screw part, 50 …… packing.

Claims (1)

[Claims] 1. A step of forming a threaded portion on an outer peripheral surface of a nozzle portion projecting inward from a tank wall surface, and a step of lining the inner surface of the tank wall surface with a predetermined lining material excluding the nozzle portion, A cylindrical member made of a predetermined lining material and having a threaded portion threadedly coupled to the threaded portion formed on the outer peripheral surface of the nozzle portion is formed on the inner circumferential surface, and the threaded portion of the nozzle portion is threadedly coupled to the nozzle portion. A tank inner surface lining method comprising: a covering step; and a step of welding a cylindrical member covering a nozzle portion and a lining material for lining an inner surface of a tank wall surface.