JPH0747296B2 - Lining method for pipe with flange - Google Patents

Description

The present invention relates to a method for lining a synthetic resin pipe on the inner surface of a pipe having a flange at the end of the present invention.

(Prior Art) Conventionally, the following two types of methods are generally known as methods for lining a flanged pipe of this type.

The first method is the method described in Japanese Examined Patent Publication No. 56-37889, in which a guide member is provided at the outer edge of the flange of the flanged pipe 51 in which the lining material 52 softened by heating is inserted as shown in FIG. 53 is a method of connecting 53 and expanding the inside of the lining material by filling it with a heated and pressurized liquid to bring the lining material 52 into close contact with the inner surface of the pipe and at the same time close contact with the outer end surface of the flange. This is called the “simultaneous expansion method”.

The second method is a method that has been traditionally practiced, and after a lining material made of a thermoplastic synthetic resin inserted into a flanged pipe is adhered to the inner surface of the flanged pipe, the pipe end flange is then attached. This is a method in which the lining material, which has been projected outward by a portion and has already been cooled, is heated and softened again, is pressed against the outer end surface of the flange, and is bonded via an adhesive. As a method of adhering the lining material to the inner surface of the flanged pipe in this first step, a method of injecting a heating and pressurizing fluid into the lining material to expand the lining material in the radial direction and adhere it via an adhesive agent Alternatively, by heating the flanged pipe in which the lining material is inserted as a whole, the heat-foaming adhesive previously applied to the inner surface of the flanged pipe is foamed to cause the lining material to be applied to the inner surface of the flanged pipe. A method of bonding is used.

The above-mentioned second method is generally called a "rear collar return method".

(Problems to be Solved by the Invention) However, in the first method, that is, the “simultaneous expansion method”, when the lining material is expanded, a guide is formed to form a closed space that defines a deformation range of the lining material. It is unavoidable to use a large jig called a member, and the wall thickness of the lining material adhered to the outer end surface of the flange becomes thinner toward the outer circumference, so the flange surface after lining does not become flush and the pipes It interferes with flange connection. In addition, since the gap between the pipe and the guide member and the lining material is a closed space, air bubbles remain on the adhesive surface of the lining material in the process of radial expansion of the lining material, which adversely affects the adhesive strength. There is.

Further, in the second method, that is, the “rear collar return method”, two heating steps of reheating the lining material that has already been allowed to cool and projects outward from the pipe end flange portion are required. There is a risk of the phenomenon that the lining layer at the end portion is peeled off by the reheating.

(Means for Solving Problems) The present invention solves the above-mentioned various problems inherent in the prior art by using a heat-expandable lining material that expands to an outer diameter larger than the inner diameter of the pipe. The object of the invention is to provide a heat-expandable lining material having an outer diameter larger than the inner diameter of the flanged pipe when it is inserted into the flanged pipe and attached with the flange through an adhesive. Inserting into the inner surface of the main part of the pipe, heating and temporarily adhering, the pipe end of the flanged pipe while keeping the pipe end of the lining material protruding outward from the pipe end while keeping the pipe end in a softened state. A step of pressing back the flange on the outer end surface and bringing them into close contact with each other with an adhesive, pressing a blind flange against both flanges of the flanged pipe, and pressing the lining material that is tightly adhered to the outer end surface of the flange to the flange end surface. Forming between Rutotomoni closed space, consists in lining method of flanged tube made of the step of cooling in a state in which injecting a pressurized fluid into the closed space.

(Operation) In the present invention, since the tubular lining material made of thermoplastic synthetic resin has the property of having an outer diameter larger than the inner diameter of the flanged pipe when expanded, the lining material is After heating and bringing it into close contact with the inner surface of the main part of the flanged pipe, the inner surface of the main part is pressed against the lining material even if the temperature slightly decreases while performing flange and flange in the next step. Since the stress to be attempted is inherent, the diameter is not immediately reduced and a gap is not formed between the inner surface of the main pipe and the inner surface. In other words, the lining material has an expanding force that tends to make it larger than the inner diameter of the flanged pipe, so even if the lining material is allowed to cool to some extent during the collar bending work, there is a portion that tries to shrink the wire due to the cooling. They are canceled by the action of the diametrical expansion force, and try to maintain the state in which they are in close contact with the inner surface of the main pipe portion of the flanged pipe.

Further, since the pipe end of the lining material is held in the softened state, it can be easily returned to the outer end face of the flange. Further, the lining material is firmly pressed and brought into close contact with the outer end face of the flange and the inside of the main pipe portion by the action of the blind flange pressed against both pipe ends of the flanged pipe and the pressurized fluid injected into the lining material.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 are views for explaining one embodiment of the present invention in the order of steps. FIG. 1 is an explanatory view showing a partial cross-sectional view of a process of performing a flange, in which 1 is a pipe with a flange, 2 is a lining material, and 3 is a warm air heater.

The flanged pipe 1 is a main pipe portion 11 having a straight pipe shape and the main pipe portion 11
Is made of iron and comprises a flange 12 protruding from the outer peripheral portion of the pipe end. However, the flanged tube 1 may be any material as long as it is not deformed by heating, and its material is not particularly limited.

A hot-melt adhesive such as a rubber-based or synthetic resin-based adhesive is applied in advance to the inner surface of the main pipe portion 11 and the outer end surface of the flange 12 or the outer surface of the lining material 2, and the material is sufficiently dried to remove the lining material 2. Insert into the flanged tube 1. The lining material 2 is a tubular body made of a thermoplastic synthetic resin and having an outer diameter slightly smaller than the inner diameter of the flanged pipe 1, and is heated to heat the flanged pipe 1
It has the property of expanding and expanding to an outer diameter larger than the inner diameter of. Here, a vinyl chloride resin pipe having an outer diameter which is about 5 to 10% larger than the inner diameter of the flanged pipe 1 when heated and expanded is used. Next, the flanged tube 1 with the lining material 2 inserted therein is put into a heating furnace, and the lining material 2 is heated to 110 to 150 ° C. In this way, the flanged pipe 1 adhered to the inner surface of the main pipe portion 11 by expanding and expanding the lining material 2 through the hot melt type adhesive is taken out from the heating furnace, and the pipe end of the flanged pipe 1 is moved outward. The warm air heater 3 prevents the lining material pipe end portion 21 protruding to the side from cooling, and the pipe end portion 21 is attached to the outer end surface of the flange 12 with an adhesive agent while maintaining the softened state. In order to bring them into intimate contact with each other, the clasp is performed manually or by using a clapper.

Next, the cooling process of the present invention will be described with reference to the partially omitted sectional view shown in FIG. Immediately after performing the collar-turning in the previous process, the lined flanges 21, 21 '
The blind flanges 4 and 4'are pressed in the axial direction of the pipe toward the center of the pipe. The blind flange 4 is provided with a through hole 41, and pressurized fluid, preferably air, is supplied from the through hole 41 to the main portion.
It is poured into the inside of the lining material 2 closely attached to the inner surface of 11.
Therefore, the pressing force for pressing the blind flanges 4 and 4'needs to be larger than the pressure of the pressurized fluid.

As described above, the work of removing the flanged pipe 1 in which the lining material 2 is in close contact with the inner surface of the main pipe portion 11 from the heating furnace and applying pressure to the inside with air or the like must be performed as quickly as possible. Steel tube (caliber 100
mm) When a heat-expandable vinyl chloride pipe with an outer diameter that is 10% larger than the inner diameter is used as the lining material, 20
If it is allowed to cool in the outside air temperature of ℃, there is a time margin of about 10 minutes before a gap is formed between the steel pipe and the lining material, so the above-mentioned work should be performed during this time.

(Effects of the Invention) As described above, according to the present invention, it is not necessary to reheat the pipe end portion for bending back, and it suffices to simply maintain the heating state. It is possible to form a firmly adhered lining layer without floating or peeling off on the entire inner surface, especially near the tube end. Also, since the free end of the thermally expandable lining material is turned back, a lining layer with a substantially uniform thickness can be formed on the outer end surface of the flange, and the watertightness of the flange connection during piping can be improved. You can

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of the present invention in a partial cross section,
2 is a partially omitted sectional view showing the next step in the same embodiment of the present invention, and FIG. 3 is a sectional view showing the prior art. 1 …… Flanged pipe, 11 …… Main pipe part 12 …… Flange, 2 …… Lining material 3 …… Hot air heater, 4,4 ′ …… Blind flange

Claims (1)

[Claims] 1. A method of lining the inner surface of a main pipe portion of a flanged pipe and the outer end face of the flange with a tubular lining material made of a thermoplastic synthetic resin, wherein the flanged pipe is expanded at the time of expansion. A step of inserting a heat-expandable lining material having a property of having an outer diameter larger than an inner diameter into an inner surface of a main portion of the flanged pipe through an adhesive, and heating and temporarily adhering the lining material, of the flanged pipe. A step of holding the pipe end portion of the lining material protruding outward from the pipe end in a softened state and pressing the pipe end portion to the outer end surface of the flange by pressing and adhering the pipe end portion via an adhesive; With the blind flange pressed against both flanges, the lining material that is in close contact with the outer end surface of the flange is pressed against the flange end surface to form a closed space, and pressurized fluid is injected into the closed space. Lining method of flanged tube made of a step of retirement.