JPH08166094A - Pipe end corrosionproof core - Google Patents

Abstract

PURPOSE: To prevent occurrence of rust at an end portion of inside coated steel pipe connecting to a piping part by making a core proper with a highly elastic synthetic resin and then forming on its outer peripheral surface, in order, a taper portion of increasing diameter, an outer peripheral groove, a taper surface portion of increasing diameter and a screw portion for piping. CONSTITUTION: An outer peripheral screw portion 1a of a core proper 1 is screwed in an inner screw 3 for piping of a piping member proper 3, and an end face 1g of an inner end portion 1g is pressed against a bottom portion 3b of an inner screw 3a, so that leakage of fluid within pie is prevented. Then, when an inside coated steel pipe 6 is screwed on an internal screw 3, a lining layer 7 on inside surface of the inner surface coated steel pipe 6 hits a taper portion 1d in two steps of increasing diameter on outside of the core proper 1, so that the latter is pressed/deformed, and the former is pressed due to high elasticity of the core proper 1. The, lining layer 7 presses against a steel member 4 and deforms it, so that the seal member 4 is in pressed state due to its rubber elasticity, attaining the sealing. It is then further pressed in a taper surface portion 1e. Accordingly, a pipe end portion 6b without lining is prevented from rusting due to inside fluid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to water supply using a steel pipe coated with an inner surface to prevent corrosion, such as a polyethylene powder lined steel pipe or a hard vinyl chloride lined steel pipe.
Pipe fittings used in piping systems for hot water supply,
A pipe end anticorrosion core for piping components such as valves.

[0002]

2. Description of the Related Art In order to prevent the fluid in a pipe from coming into contact with the inner surface of a steel pipe and generating rust, and the product thereof is dissolved in the fluid and contaminates the fluid, in a piping system for water supply, hot water supply, etc., Steel pipes with an inner coating such as polyethylene powder lining steel pipes and vinyl chloride lining steel pipes are often used, and pipe joints, valves, etc. connected to these inner coating steel pipes are also coated with these inner coating steel pipes. In order to prevent the fluid from being contaminated by generating rust on the uncoated end surface of the pipe, the pipe end is generally provided with an anticorrosion structure.

FIG. 6 is a partial cross-sectional view showing a state of use of an example of a conventional pipe end anticorrosion joint.
This is disclosed as a conventional example in the publication.
This pipe end anticorrosion joint 10 is provided with synthetic resin sleeve portions 12a and 12b, which are concentric with the inner threads 11a and 11b, inside a joint body 11 having tapered inner threads 11a and 11b at both ends. And inner surface coated steel pipes 13 and 14 screwed into both ends of the joint body 11.
The internal passages 13a and 14a are connected by the internal passage 12c of the sleeve portions 12a and 12b.

Such a pipe end anti-corrosion joint 10 is constructed such that the outer peripheral surfaces of the sleeve portions 12a and 12b and the inner surface coated steel pipes 13 and 1 are covered.
It is designed to prevent the fluid in the pipe from leaking out due to the contact with the inner peripheral surface of No. 4, but the shapes and dimensions of both contact surfaces,
The surface condition is not sufficient, and sometimes the fluid in the pipe oozes out from this contact surface to generate rust at the pipe end 13b or 14b, and this rust oozes into the pipe from the contact surface and pollutes the fluid in the pipe. Since this joint 10 may be damaged or broken, the pipe ends 13b, 1
In general, the pipe end portions 13b and 14b are coated with an anticorrosion agent so that the fluid does not adhere to 4b, and then the inner surface coated steel pipes 13 and 14 are screwed into the joint body 11.

However, the work of applying the anticorrosive agent to the pipe end portions 13b and 14b is not only troublesome and time-consuming, but also requires skill to completely cover the pipe end portions 13b and 14b by applying the anticorrosive agent. However, there was a problem of lack of workability and reliability.

FIG. 7 is a partial sectional view showing a pipe end anticorrosion joint devised to solve the above problems, and FIG.
FIG. 8 is a partial cross-sectional view showing a usage state of the pipe end anticorrosion joint shown in FIG. 7, which is shown as an example of a device in the above-mentioned Japanese Utility Model Publication No. 25582/1992. In FIGS. 7 and 8, the joint body 21 of the pipe end anticorrosion joint 20 has a taper inner screw 21a for screwing the inner surface coated steel pipe 22 into the end, as in the pipe end anticorrosion joint 10 of FIG. A sleeve portion 23 made of synthetic resin is fitted into the inner diameter portion 22a of the inner surface coated steel pipe 22.

An annular lip portion 23a having elasticity is integrally provided on the outer peripheral surface of the sleeve portion 23, and the annular recessed portion 2 is provided adjacent to the outer side of the root portion of the lip portion 23a.
3b is provided, and the recessed portion 23b is provided with a sealing material 24 having elasticity that is deformed by being pressed against the inner diameter portion 22a of the inner surface coated steel pipe 22.

FIG. 8 is a partial sectional view showing a state in which the inner surface coated steel pipe 22 is screwed into the pipe end anticorrosion joint 20.
When the inner surface coated steel pipe 22 is screwed into the pipe end anti-corrosion joint 20, the inner surface coated steel pipe 22 pushes the seal member 24, but since the seal member 24 is backed up by the lip portion 23a, it is pushed over the lip portion 23a. Without being deformed, the inner surface 22a of the inner surface coated steel pipe 22 is pressed and deformed, the deformation also presses the lip portion 23a and bends inward, and the elastic force is applied to the sealing material 24. Restoring force due to its own elasticity and lip 2
It is pressed against the inner diameter portion 22a of the inner surface coated steel pipe 22 by the elastic force backed up by 3a, and the gap between the inner diameter portion 22a of the inner surface coated steel pipe 22 and the sleeve portion 23 is kept watertight.

By the way, as the so-called inner surface coated steel pipe, a polyethylene powder-lined steel pipe having polyethylene powder fused to the inner surface of the steel pipe and a hard vinyl chloride lining steel pipe bonded with a synthetic resin pipe The thickness of the lining layer is thin in the former case and thick in the latter case. For this reason, even for the inner surface coated steel pipe having the same outer diameter, the inner diameter dimension varies depending on the type of the lining layer.

For this reason, the conventional pipe end anticorrosion joint 10 described above with reference to FIG.
The outer diameter of the sleeve portion 12a must be different according to 14, and the assembling cannot be performed or the assembling can be performed unless the dimensions of the steel pipes 13 and 14 and the joint 10 are properly combined. The inconvenience of not being able to prevent corrosion occurs.

The pipe end anticorrosion joint 20 shown in FIGS. 7 and 8 is one in which the inner surface coated steel pipe 22 is a polyethylene powder lined steel pipe having a thin lining layer 22a. In the case of a hard vinyl chloride lining steel pipe having a large thickness, the sealing material 24 and the lip portion 23a are excessively deformed to the extent of being damaged, and the purpose of pipe end anticorrosion cannot be achieved.

Therefore, in the device disclosed in the above publication, as an example thereof, as shown in FIG.
b is provided with lip portions 23a and 23c adjacent to the outer side thereof, and the sealing material 24 has a circular cross-sectional shape made of a material that swells due to water absorption such as aqua elastomer and increases its volume. Is designed to have a size that does not block the gap between the two lip portions 23a and 23c in the unswelled state.

FIG. 9 shows a polyethylene powder lining steel pipe 22 having a thin lining layer 22a on the pipe end anticorrosion joint 20.
FIG. 4 is a partial cross-sectional view showing a state where the sealing material 24 is screwed in, in which the sealing material 24 is not swollen. FIG. 10 is a partial cross-sectional view showing a state after the sealing material 24 has swollen due to water absorption from the state of FIG. 9, and the swollen sealing material 24 seals between the sleeve portion 23 and the inner surface coated steel pipe 22. are doing. FIG. 11 is a partial cross-sectional view showing a state in which a hard vinyl chloride lining steel pipe 25 having a thick lining layer 25a is screwed in, and the sealing material 24 is swollen, and the swollen sealing material 24 is 23 and inner surface coated steel pipe 2
The space between 5 and 5 is sealed.

In the structure for sealing the space between the sleeve portion 23 and the inner surface coated steel pipe 22 or 25 by using a material such as aqua elastomer which swells due to water absorption to increase its volume as the sealing material 24 as described above. , The fluid passes through between the sealing material 24 and the inner surface coated steel pipe 22 or 25 before the sealing material 24 swells, and the pipe end 22b or 2
5b and the remaining threaded portion 21b of the taper inner screw 21a of the joint body 21 and generate rust at these portions, which pushes the sealing material 24 to flow out into the fluid and stain the fluid, It may be damaged or broken.

[0015]

As described above, the problem to be solved by the present invention is, in the conventional pipe end anticorrosion joint as shown in FIG. 6, the inner peripheral surface of the inner surface coated steel pipe and the pipe end anticorrosion. The fluid in the pipe oozes out due to imperfections in the shape, dimensions, surface condition, etc. of the contact surface with the outer circumference of the sleeve part of the joint, causing rust at the pipe end, and this rust oozes into the pipe from the contact surface. Is to contaminate the fluid of the pipe, damage or break this joint, and to prevent this, it requires skill to reliably coat the pipe end with an anticorrosive agent, which requires workability and reliability. It is lacking. Furthermore, this joint cannot be assembled without ensuring the combination of the dimensions of the steel pipe and the joint for inner surface coated steel pipes having different inner diameter dimensions because the inner surface lining layers have different thicknesses,
This is to solve the problem that corrosion cannot be prevented even if it can be assembled.

Further, the pipe end anticorrosion joint of FIGS. 7 and 8 is suitable for an inner surface coated steel pipe having a relatively large inner diameter with a thin lining layer such as a polyethylene powder lined steel pipe, but a hard vinyl chloride lining. An inner surface coated steel pipe with a thick lining layer and a relatively small inner diameter, such as a steel pipe, is excessively deformed to the extent that the sealing material and the lip portion are damaged, and there is a problem that the function of preventing the pipe end deteriorates. are doing.

In particular, FIGS. 9 to 1 which are examples for addressing the problems of the pipe end anticorrosion joint shown in FIGS. 7 and 8 above.
In the pipe end anticorrosion joint shown in 1, a sealing material made of a material that swells due to water absorption such as aqua elastomer and remarkably increases its volume, swells due to water absorption, and the inner surface coated steel pipe and this pipe end anticorrosion joint Before sealing the space
There is a problem that the fluid adheres to the pipe end and the remaining threaded portion and rusts at these portions, and the rust stains the fluid and damages or breaks the joint.

[0018]

The pipe end anticorrosion core of the present invention is for solving the problems of the above-mentioned conventional pipe end anticorrosion joint and can be applied to other piping parts such as valves. To do so, it was constructed as follows.
The fluid in the pipe is attached to the inside of piping components such as pipe joints and valves, and the fluid in the pipe is supplied from between the inner peripheral surface of the lined inner peripheral surface of the steel pipe which is screwed into the internal threads for piping of these piping components. A pipe end anticorrosion core having a substantially cylindrical shape in which a sealing material that seals against leakage toward the pipe end is installed in an outer peripheral groove, and the pipe end anticorrosion core is made of highly elastic synthetic resin, On the outer peripheral surface, a taper portion whose diameter is increased by one step or multiple steps from the outer end portion inserted into the inner surface coated steel pipe, an outer peripheral groove for mounting a sealing material, a taper surface portion whose outer diameter is increased, and an outer peripheral threaded portion are sequentially formed. The outer peripheral threaded portion is screwed into an inner thread for piping of the above-mentioned piping component so that the pipe end anticorrosion core is attached to the body of the piping component.

In this case, a plurality of grooves or ridges may be formed on the inner peripheral surface, and one or both side surfaces of the outer peripheral groove may be connected to the outer peripheral surface adjacent thereto by round chamfering.
The end surface of the inner end portion with respect to the outer end portion may be formed in a conical shape or a funnel shape, a recessed step portion may be provided on the outer peripheral side of the end surface of the inner end portion, and the sealing material may have a cross-sectional shape substantially equal to that of the inner end portion. It is preferably made of a triangular synthetic rubber having a peripheral surface as a base. Further, it is preferable to use a pipe end anticorrosion core for a pipe joint having the same shape as that of the above-described two pipe end anticorrosion cores connected so that their outer ends are at both ends. Further, these pipe end anticorrosion cores may be attached to form pipe fittings, valves and other piping parts.

[0020]

Since the pipe end anticorrosion core of the present invention is constructed as described above, first, the pipe end anticorrosion core is formed by screwing the outer peripheral threaded portion into the inner thread for piping of pipe fittings, valves and other piping parts. The inner end is strongly screwed in so that it is pressed against the bottom of the inner screw. In this case, if a plurality of grooves or ridges formed on the inner peripheral surface of the tube end anticorrosion core are hooked with a screwing tool, they can be easily and strongly screwed. Also, since the end face of the inner end portion is formed into a conical shape or a funnel shape, this end face and the bottom portion of the inner screw for piping of the piping component are pressed against each other in a narrow area, which results in high surface pressure and It is possible to reliably prevent the fluid in the pipe from leaking from the portion. Furthermore, if the recessed step portion provided on the outer peripheral side of the end surface of the inner end portion is filled with the sealing agent, the prevention of leakage becomes more reliable.

Next, when the inner surface coated steel pipe is screwed into the inner screw for piping of this pipe end anticorrosion type piping component, the lining layer on the inner surface of the pipe end portion of the inner surface coated steel pipe is located on the outer end side of the pipe end anticorrosion core. It hits a taper portion having a large diameter in one or more steps and is compressed and deformed to be in a state of pressure contact due to the high elasticity of the tube end anticorrosion core. When the inner surface coated steel pipe is screwed in further, the lining layer on the inner surface of the pipe end pushes and deforms the sealing material,
The sealing material is brought into a state of pressure contact by rubber elasticity, so that the sealing is surely performed irrespective of the shape, size and surface condition of the lining surface. In this case, if the inner surface coated steel pipe has a thick lining layer and a small inner diameter, the deformed seal material is sandwiched between the outer peripheral surface of the pipe end anticorrosion core and the lining layer of the inner surface coated steel pipe. However, the outer peripheral surface of this portion of the pipe end anticorrosion core also has a tapered portion with a large diameter, and the inner surface coated steel pipe is screwed into it to make stronger pressure contact. Even if there is a difference in the screw-in depth of the inner surface coated steel pipe, there is no difference in the sealing performance.

Since one or both side surfaces of the outer peripheral groove in which the sealing material is mounted and the outer peripheral surface adjacent to the outer peripheral groove are connected by a round chamfer, the inner end coated steel pipe of the inner surface coated steel pipe is deformed by the deformed portion of the pipe end anticorrosion core. Prevents damage to the lining surface and seal material from deformation.

When the shape of the sealing material is a substantially triangular shape with the inner peripheral surface as the base, the sectional area is smaller as the inner peripheral surface of the inner surface coated steel pipe is closer, the deformation is easier, and the sealing performance is excellent.
However, the cross-sectional shape of the sealing material used for the tube end anticorrosion core of the present invention is not limited to this, and may be another shape such as a trapezoid, an oval, or a circle. Further, when this sealing material is made of synthetic rubber, it has excellent elasticity, chemical resistance, durability and the like. However, it is not limited to synthetic rubber depending on the use conditions, and may be formed of natural rubber or synthetic resin.

In this way, the pipe end anticorrosion core of the present invention is mounted on a pipe component such as a pipe joint and a valve, and when the inner surface coated steel pipe is connected, the pipe end is not lined by the fluid in the pipe. It is possible to surely prevent rust from being generated at the pipe end and polluting the fluid inside. Further, these operations do not require any particular skill, and are highly workable and reliable. Further, the same tube end anticorrosion core can sufficiently function even for inner surface coated steel pipes having different inner diameters because the lining layers of the inner surface coated steel pipes have different thicknesses.

When a pipe end anticorrosion core having the same shape as the two pipe end anticorrosion cores according to the present invention connected so that their outer ends are at both ends is attached to a straight pipe joint, the attaching work is performed. It is easy to obtain an economical pipe joint. Also,
The present invention also proposes a pipe joint, a valve, and other piping parts equipped with the above-mentioned pipe end anticorrosion core, and their functions are also the same as those described above.

[0026]

FIG. 1 is a partial sectional view showing an embodiment of the pipe end anticorrosion core of the present invention, and FIG. 2 shows the pipe end anticorrosion core of FIG. FIG. 3 is a partial sectional view showing a mounted state, and FIG. 3 shows a state in which an inner surface coated steel pipe having a relatively thin inner layer and a relatively large inner diameter, such as a polyethylene powder lined steel pipe, is screwed into the piping component of FIG. FIG. 4 is a partial cross-sectional view showing a state in which an inner surface-coated steel pipe having a relatively thick lining layer such as a hard vinyl chloride lining steel pipe and a relatively small inner diameter is screwed into the piping component of FIG. 2; 5 is a cross-sectional view showing an example of a pipe joint equipped with the pipe end anticorrosion core of FIG. 1. In FIGS. 1 to 5, 1 is a core body of the pipe end anticorrosion core, 2 is a pipe joint, and 3 is Main body of piping parts such as pipe joints and valves, 4 is sealing material 5 sealant, is lined steel pipe 6, 7 is a lining layer.

The core body 1 for pipe end anticorrosion is made of a highly elastic synthetic resin and has a substantially cylindrical shape. As shown in FIG. 1 to FIG. The outer peripheral threaded portion 1a of the core main body 1 is screwed into the inner thread 3a for piping of the main body 3, and is attached to the outer peripheral groove 1b of the core main body 1, and the sealing material 4 is attached to the core main body 1 and the pipe. The inner peripheral surface 7 of the inner surface coated steel pipe 6 in which the outer thread 6a is screwed into the inner thread 3a for piping of the body 3 of the component
The fluid in the pipe from between a and the pipe end portion 6b of the inner surface coated steel pipe 6
It prevents it from leaking toward.

An inner surface coated steel pipe 6 is provided on the outer peripheral surface of the core body 1.
From the outer end 1c to be inserted into the taper, a taper portion 1d having a larger diameter in one step or a plurality of steps, a taper portion 1j, an outer peripheral groove 1b for mounting a sealing material, a taper surface portion 1e having a larger diameter, and an outer peripheral thread portion 1a are sequentially formed. This peripheral thread 1
a is screwed into the internal thread 3a for piping of the body 3 of the piping component, and the core body 1 is mounted inside the piping component such as the pipe joint 2 and the valve.

Further, a plurality of grooves 1f are formed on the inner peripheral surface of the core body 1, and the side surfaces on both sides of the outer peripheral groove 1b and the tapered surfaces 1d and 1e adjacent thereto are round chamfered 1i.
Tied with. Further, the end portion 1g of the inner end portion with respect to the outer end portion 1c is formed in a funnel shape, and a step portion 1h retracted is provided on the outer peripheral side of the end surface 1g, as shown in FIGS. 2 to 5. This core body 1 is the body 3 of piping parts
When it is mounted on, the step portion 1h is filled with the sealing agent 5.

The cross-sectional shape of the sealing material 4 is substantially the inner peripheral surface 4a.
Although it is made of a substantially triangular synthetic rubber whose base is, the cross-sectional shape is not limited to this.

Next, the operation will be described based on the embodiment shown in FIGS. First, in the core body 1, the outer peripheral threaded portion 1a is connected to the pipe joint 2 and the body 3 of a piping component such as a valve.
It is screwed into the inner screw 3a for piping, and is strongly screwed so that the end face 1g of the inner end is in pressure contact with the bottom portion 3b of the inner screw 3a. In this case, if a plurality of grooves 1f formed on the inner peripheral surface of the core body 1 are hooked with a screwing tool, they can be easily and strongly screwed. Further, since the end face 1g of the inner end portion is formed in a funnel shape, this end face 1g
And the bottom portion 3b of the internal thread 3a for piping of the main body 3 of the piping component are in pressure contact with each other in a narrow area of the outer peripheral portion, so that the surface pressure is high and the leakage of the fluid in the pipe from this pressure contact portion can be reliably prevented. . Further, if the recessed step portion 1h provided on the outer peripheral side of the end face 1g of the inner end portion is filled with the sealant 5, the leakage can be prevented more reliably. FIG. 2 shows this state.

Next, when the inner surface coated steel pipe 6 is screwed into the inner screw 3a for piping of the pipe end anticorrosion type piping component, the lining layer 7 on the inner surface of the pipe end portion 6b of the inner surface coated steel pipe 6 becomes the pipe end anticorrosion core. The two taper portions 1d on the outer end side having a larger diameter hit the taper portion 1d, which is compressed and deformed, so that the core body 1 is brought into a state of pressure contact due to its high elasticity. Further, when the inner surface coated steel pipe 6 is screwed in, the lining layer 7 on the inner surface of the pipe end portion 6b pushes and deforms the sealing material 4, and the sealing material 4 is brought into a state of pressure contact by rubber elasticity, and the inner peripheral surface 7a of the lining layer 7a. Regardless of the shape, size, surface condition, etc., the sealing will be ensured. FIG. 3 shows this state, and even if there is a difference in the screwing depth of the inner surface coated steel pipe 6, there is no difference in the sealed state.

In this case, when the inner surface-coated steel pipe 6 has a thick lining layer 7 and a small inner diameter like a hard vinyl chloride lining steel pipe, the deformed seal 4 has the outer peripheral surface of the core body 1 and the inner surface-coated steel pipe 6 However, the outer peripheral surface of this portion of the core body 1 also has a tapered surface portion 1e with a larger diameter, and the inner surface coated steel pipe 6 is screwed in to make a stronger pressure contact. Will be done. FIG. 4 shows this state, and even if there is a difference in the screwing depth of the inner surface coated steel pipe, there is no difference in the sealing performance.

Further, the outer peripheral groove 1b in which the sealing material 4 is mounted
Side surfaces on both sides of the taper and the taper portion 1 which is the outer peripheral surface adjacent to the side surfaces
Since the d and the tapered surface portion 1e are connected by the round chamfer 1i, the inner peripheral surface 7a of the lining layer 7 of the inner surface coated steel pipe 6 is prevented from being damaged by the deformed portion of the pipe end anticorrosion core 1, and The seal material 4 is prevented from being damaged when it is deformed.

When the shape of the sealing material 4 is a substantially triangular shape having the substantially circumferential surface 4a as the base, the inner circumferential surface 7 of the inner surface coated steel pipe 6 is formed.
The closer to a, the smaller the cross-sectional area, the easier the deformation, and the better the sealing performance. However, the cross-sectional shape of the sealing material 4 used for the tube end anticorrosion core 1 in this example is not limited to this, and may be another shape such as a trapezoid, an egg shape, a bullet shape, or a circle. When the sealing material 4 is made of synthetic rubber, it is excellent in elasticity, chemical resistance, durability and the like. However, it is not limited to synthetic rubber depending on the use conditions, and may be formed of natural rubber or synthetic resin.

In this way, the core body 1 for pipe end anticorrosion according to the present invention is mounted on the pipe fitting 2, the piping component such as the valve, and when the inner surface coated steel pipe 6 is connected, the pipe inside depends on the fluid inside the pipe. It is possible to surely prevent rust from being generated on the unlined pipe end of the end 6b and pollute the internal fluid. Further, these operations do not require any particular skill, and are highly workable and reliable. Furthermore, even for inner surface coated steel pipes 6 having different inner diameters due to different thicknesses of the lining layer 7 of the inner surface coated steel pipe 6, the same pipe end anticorrosion core 1
Can be fully functional.

[0037]

INDUSTRIAL APPLICABILITY The pipe end anticorrosion core of the present invention is used by mounting it on piping parts such as pipe joints and valves, and in the piping system for water supply and hot water supply using the inner surface coated steel pipe, these inner surface coated steel pipes are used. The fluid inside the pipe is prevented from coming into contact with the uncorroded end of the pipe to prevent the formation of rust, and the formation of rust prevents the fluid from being contaminated and the rust from damaging or damaging this piping component.

Further, the same pipe end anticorrosion core can be commonly used for inner surface coated steel pipes having different lining layer thicknesses and different inner diameter dimensions. Further, even if there is a difference in the screw-in depth for connecting the inner surface coated steel pipe, there is no difference in the pipe end anticorrosion effect.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing an embodiment of a tube end anticorrosion core of the present invention.

FIG. 2 is a partial cross-sectional view showing a state in which the pipe end anticorrosion core of FIG. 1 is mounted inside a piping component such as a pipe joint and a valve.

FIG. 3 is a partial cross-sectional view showing a state where an inner surface coated steel pipe having a relatively thin lining layer and a relatively large inner diameter is screwed into the piping component of FIG.

FIG. 4 is a partial cross-sectional view showing a state where an inner surface coated steel pipe having a relatively thick lining layer and a relatively small inner diameter is screwed into the piping member of FIG.

5 is a sectional view showing an example of a pipe joint equipped with the pipe end anticorrosion core of FIG. 1. FIG.

FIG. 6 is a partial cross-sectional view showing a usage state of an example of a conventional pipe end anticorrosion joint.

FIG. 7 is a partial cross-sectional view showing a conventional pipe end anticorrosion joint.

FIG. 8 is a partial cross-sectional view showing a conventional pipe end anticorrosion joint.

FIG. 9 is a partial cross-sectional view showing a conventional pipe end anticorrosion joint.

FIG. 10 is a partial cross-sectional view showing a state after the sealing material has swollen from the state of FIG.

FIG. 11 is a partial cross-sectional view showing a case where the inner coating steel pipe has a thick lining layer in the state of FIG.

[Explanation of symbols]

 1 Core Main Body for Corrosion Protection 1a External Thread 1b External Groove 1c Outer Edge 1d Tapered Part 1e Tapered Surface 1f Groove 1g Inner End Face 1h Step 2 Pipe Joint 3 Piping Part Body 3a Internal Screw 4 Sealant 4a Inner peripheral surface 5 Sealing agent 6 Inner surface coated steel pipe 6a Outer screw 6b Pipe end 7 Lining layer 7a Inner peripheral surface

Claims (5)

[Claims] 1. A fluid in the pipe is introduced from between a lined inner peripheral surface of an inner surface-coated steel pipe which is mounted inside a pipe component such as a pipe joint and a valve and screwed into an internal thread for piping of these pipe components. A substantially cylindrical pipe-end anticorrosion core in which a sealing material that seals against the pipe end of the inner surface coated steel pipe is installed in the outer peripheral groove, and the core body of the pipe-end anticorrosion core is elastic. Made of high synthetic resin, the outer peripheral surface has a taper portion with a diameter larger by one or more steps than the outer end portion inserted into the inner surface coated steel pipe, an outer peripheral groove for mounting a sealing material, a taper surface portion with a larger diameter, and the above. A pipe end anticorrosion core, characterized in that an outer peripheral thread portion to be screwed into an inner thread for piping of the above-mentioned piping component is sequentially formed. 2. The pipe end anticorrosion core according to claim 1, wherein a plurality of grooves or ridges are formed on the inner peripheral surface of the core body. 3. The pipe end anticorrosion core according to claim 1, wherein one or both side surfaces of the outer peripheral groove and an outer peripheral surface adjacent thereto are connected by a round chamfer. 4. The pipe end anticorrosion core according to claim 1, wherein an end surface of the inner end portion with respect to the outer end portion is formed in a conical shape or a funnel shape. 5. The pipe end anticorrosion according to any one of claims 1 to 4, characterized in that the sealing material is made of a synthetic rubber having a substantially triangular cross-section with an inner peripheral surface as a base. core.