JP2020133751A - Pumping pipe - Google Patents

Abstract

To provide a pumping pipe in which only a site that is relatively severely worn and needed to be replaced can be replaced, thereby reducing a maintenance cost.SOLUTION: In a steel pipe 10, a notch part 13 is provided in a high wear region 12a where an inner wall is relatively worn compared to other portions, and a wear resistant member 20 is detachably attached to the notch part 13. The wear resistant member 20 has an outside steel plate 21, and hard layers 40, 40A containing hard chips or hard particles formed on the inside surface of the outside steel plate 21.SELECTED DRAWING: Figure 1

Description

The present invention relates to a pumping tube.

The pumping pipe (transport pipe) applied to various facilities is made of sand, iron balls, etc. provided to remove sediments and dirt of the material flowing in the pipe, in addition to the wear caused by the material flowing in the pipe. There is wear, and the inside of the pumping pipe is damaged due to the wear caused by these various factors, and the entire pumping pipe has to be replaced. Further, in the concrete pump method, it is known that when concrete flows through the pumping pipe, the inside of the pumping pipe is worn due to friction between the concrete and the inside of the pumping pipe. It has been inspected and all of the pump pipes have been replaced if necessary. Here, "all of the steel pipes" means all of the steel pipes of a predetermined length, for example, all of the elbow pipes in which the straight pipe and the elbow pipe are connected, and the internal wear is relatively severe. There is.

Here, techniques relating to wear-resistant structures of wear-resistant pipes and pipes have been proposed. For example, in a wear-resistant double pipe in which a ceramic pipe is inserted into a metal pipe to strengthen the inner wall surface, a wear-resistant coating layer is provided on a contact surface with a fluid at a connecting portion between the ceramic pipes and has a U-shaped cross section. A wear-resistant double tube having a metal spacer made of a ring of the above has been proposed (see, for example, Patent Document 1).
Further, for example, at a bent portion of a pipe for transferring powder or granular material made of silica sand, which has a powder or granular material pool (sand pool) for colliding with the silica sand transferred to this pipe. Abrasion resistant structure has been proposed. A wear-resistant material (lining material) made of ceramics or cermet, which has a hardness greater than the hardness of silica sand, is provided at the site where the silica sand that collides with the sand pool and bounces off, and the silica sand that bounces off after colliding with the sand pool is provided. By colliding with a wear-resistant material having a hardness larger than the hardness of the silica sand, the wear-resistant material is less likely to be worn, so that the replacement frequency is reduced and the service life of the pipe is extended (for example, patent). Reference 2).
Further, a method for forming a hardened overlay layer in which hard particles can be evenly distributed in the hardened overlay layer has also been proposed. Specifically, a hollow pipe filled with hard particles is placed on the base material, and a welding torch is brought close to the base material above the hollow pipe to generate an arc, thereby melting the hollow pipe and the surface of the base material. By forming a molten pool, causing hard particles to flow out from the inside of the hollow pipe into the molten pool by melting the hollow pipe, and moving the welding torch along the hollow pipe, the hard particles are formed in the hardened overlay on the surface of the base metal. This is a method for forming a hardened overlay so that the particles are evenly distributed (see, for example, Patent Document 3).

JP-A-2002-31275 Japanese Unexamined Patent Publication No. 2001-50474 Japanese Unexamined Patent Publication No. 2018-1172

The entire area of the pumping pipe is not worn to the same extent, and the wear of some areas where the degree of wear is relatively severe has forced the entire replacement of the steel pipe as described above. , The conventional pumping pipe has a problem that unnecessary maintenance cost is incurred. Further, even in the wear-resistant structures of the wear-resistant pipes and pipes described in Patent Documents 1 to 3 described above, the means for solving the problem is not disclosed.

The present invention has been made in view of the above problems, and provides a pumping pipe capable of replacing only a part that needs to be replaced due to a relatively severe degree of wear and reducing maintenance costs. The purpose is.

In order to achieve the above object, one aspect of the pumping pipe according to the present invention is
A notch is provided in a high wear region where the inner wall of the steel pipe is relatively worn as compared with other parts, and a removable wear-resistant member is attached to the notch.
The wear-resistant member is characterized by having an outer steel plate and a hard layer containing hard chips or hard particles formed on the inner surface of the outer steel plate.

According to this aspect, a notch is provided in a high wear region where the inner wall of the steel pipe is relatively worn as compared with other parts, and a removable wear-resistant member is attached to the notch. As a result, when the high wear area wears earlier than other parts, it is necessary to remove the wear resistant member, maintain the wear resistant member, or replace it with a new wear resistant member and attach it to the steel pipe. Only certain parts can be replaced. Therefore, the maintenance cost can be significantly reduced as compared with the conventional pumping pipe. The "high wear area" in a steel pipe includes a region such as an elbow portion of a steel pipe that can be clearly identified as being heavily worn based on past achievements and empirical rules, as well as a region identified as being heavily worn by a wear experiment or the like. Further, as a form of a hard layer containing hard particles or hard chips arranged on the inner surface of the outer steel plate forming the wear-resistant member, a cemented carbide chip (for example, tungsten carbide (WC) as a main component is baked. Examples thereof include a form in which the cemented carbide) is attached by brazing, and a form in which a hardened overlay of cemented carbide particles formed by crushing the cemented carbide tip is formed.

Further, in another aspect of the pumping pipe according to the present invention, a first flange is provided around the notch on the outside of the steel pipe so as to project outward and surround the notch.
A second flange that projects outward and comes into contact with the first flange is provided on the outer outer circumference of the wear-resistant member.
The first flange and the second flange are in contact with each other and are fixed by fixing means.
According to this aspect, the first flange around the notch portion of the steel pipe and the second flange on the outer outer circumference of the wear-resistant member are in contact with each other and are fixed by the fixing means, so that the steel pipe and the wear-resistant member are worn. The members can be firmly joined, and both can be easily attached and detached. Here, as the fixing means, bolts are inserted into the insertion holes provided at the corresponding positions in the first flange and the second flange, and the nuts are tightened. The first flange and the second flange are clamped. There is a form to fix it.

Further, in another aspect of the pumping tube according to the present invention, the hard particles are cermet particles, and the hard layer is a cured overlay layer of cermet particles.
According to this aspect, since the hard layer is formed by the hardened overlay layer of cermet particles, it is possible to form a pumping pipe having an abrasion resistant member having excellent abrasion resistance. Here, cermet is a composite material formed by mixing a powder of a hard compound such as a metal carbide or a nitride with a metal binder and sintering it. For example, a titanium-based cermet in which a titanium compound such as titanium carbide (TiC) or titanium carbide (TiCN) is bonded with nickel or cobalt can be mentioned.

Further, in another aspect of the pumping pipe according to the present invention, the hard tip is a cermet tip, and the hard layer is a welded layer of the cermet tip.
According to this aspect, since the hard layer is a welded layer of the cermet tip, it is possible to form a pumping pipe having a wear resistant member having excellent wear resistance.

Further, in another aspect of the pumping pipe according to the present invention, the cermet particles are characterized in that the cermet tip applied to a used cutting tool is a crushed recycled material.
According to this aspect, cermet chips, which have not been recycled and have been conventionally treated as industrial waste, can be effectively utilized.

Further, in another aspect of the pumping pipe according to the present invention, the notch portion is provided on the radial outer side of the elbow portion of the steel pipe.
According to this aspect, since the wear-resistant member is attached to the radial outer side of the elbow portion of the steel pipe, which is clearly found to be heavily worn, the high-wear region can be narrowed down accurately, and the scale is as large as possible. It is possible to form a pumping pipe having a small wear-resistant member.

According to the pumping pipe of the present invention, the degree of wear is relatively severe, and only the part that needs to be replaced can be replaced, and the maintenance cost can be reduced.

It is a side view of an example of the pumping pipe which concerns on embodiment. It is a side view of the state in which the wear resistant member is not attached in the pumping pipe which concerns on embodiment. It is a perspective view of an example of the wear-resistant member. It is a perspective view of an example of a hard particle layer. It is a perspective view of another example of a hard particle layer. It is a figure which shows the wear test result.

Hereinafter, the pumping pipe according to the embodiment will be described with reference to the attached drawings. In the present specification and drawings, substantially the same components may be designated by the same reference numerals to omit duplicate explanations.

[Pressure pipe according to the embodiment]
An example of the pumping pipe according to the embodiment will be described with reference to FIGS. 1 to 5. Here, FIG. 1 is a side view of an example of the pressure feed pipe according to the embodiment, and FIG. 2 is a side view of the pressure feed pipe according to the embodiment in a state where no wear resistant member is attached. Further, FIG. 3 is a perspective view of an example of the wear-resistant member, and FIGS. 4 and 5 are perspective views of an example of the hard particle layer.

In the pressure feed pipe 50, the wear resistant member 20 is detachably attached to the notch 13 provided in the high wear region 12a where the inner wall of the steel pipe 10 is relatively worn as compared with other parts. It is formed by being Here, the facilities and equipment having the target steel pipe 10 include recycling facilities such as wood crushing and transporting facilities, irregular fireproof material transporting facilities and raw material transporting facilities such as steelworks, chemical plants, muddy water shield excavators and mud shields. Examples include excavators, muddy water propulsion machines, muddy soil propulsion machines, TBMs (tunnel boring machines), concrete pump trucks, and the like.

The steel pipe 10 has a straight portion 11 and an elbow portion 12. In the steel pipe 10 of the illustrated example, the straight portion 11 and the elbow portion 12 are continuous steel pipes, but the steel pipe may be formed by connecting the straight pipe and the elbow pipe. Here, as the steel pipe 10, JIS G 3444 carbon steel pipe for general structure (STK), JIS G 3452 carbon steel pipe for transport pipe (SGP), JIS G 3454 carbon steel pipe for pressure transport pipe (STPG), and the like are applied. ..

In the steel pipe 10 having the straight portion 11 and the elbow portion 12, the region that becomes the high wear region 12a is the radial outer side surface of the elbow portion 12 in light of past achievements and empirical rules. For example, as shown in FIG. 1, the pressure-fed material flowing in the X direction in the steel pipe 10 collides with the radial outer side surface of the elbow portion 12 and changes the flow direction. Therefore, the radial direction of the elbow portion 12 The outer side surface is generally the high wear region 12a. Therefore, as is clear from FIG. 2, a notch portion 13 for attaching the wear resistant member 20 is provided on the radial outer side surface of the elbow portion 12 which is the high wear region 12a.

Then, around the notch portion 12a, a first flange 14 projecting outward and surrounding the notch portion 12a is joined to the steel pipe 10 by welding. A plurality of insertion holes 14a and 14b are provided in the first flange 14. Further, of the endlessly continuous first flange 14, the first flange 14 at the boundary with the straight portion 11 has a side view triangular reinforcing rib 15 straddling the first flange 14 and the straight portion 11 by welding. It is joined.

On the other hand, as shown in FIG. 3, the wear-resistant member 20 has a main body 21 (an example of an outer steel plate) made of a steel pipe piece or the like formed by being cut out when forming the cutout portion 13 of the steel pipe 10. A second flange 22 that projects outward from the outer circumference of the main body 21 and surrounds the main body 21 is joined to the main body 21 by welding.

When the wear-resistant member 20 is arranged in the notch 13 of the steel pipe 10 shown in FIG. 2, the endless second flange 22 is similarly applied to the endless first flange 14 in the entire area of both. The second flange 22 is attached to the main body 2 so as to be in contact with the main body 2. Further, the second flange 22 is provided with insertion holes 22a and 22b at positions corresponding to the insertion holes 14a and 14b of the first flange 14 in a state where the first flange 14 and the second flange 22 are in contact with each other. There is. At both ends of the main body 21, the side view triangular reinforcing ribs 23 straddling the main body 21 and the second flange 22 are joined by welding. Further, a plurality of lateral view annular reinforcing ribs 24 are joined to the general portion of the main body 21 by welding so as to straddle the main body 21 and the left and right second flanges 22 at intervals in the longitudinal direction. ..

As shown in FIGS. 4 and 5, various forms of hard layers 40 and 40A are provided on the inner surface of the wear-resistant member 20. The hard layer 40 shown in FIG. 4 is in a form in which a large number of cermet chips 41 are formed in layers via a welding layer 42, and the welding layer 42 is joined to the inner surface of the outer steel plate 21. Here, by applying the recycled material as the cermet chip 41, the cermet chip, which has not been recycled and has been conventionally treated as industrial waste, can be effectively utilized. In addition to the cermet tip 41, a cemented carbide tip or the like may be applied.

On the other hand, the hard layer 40A shown in FIG. 5 has a form in which a large number of cermet particles 45 are dispersed in the cured overlay layer 46, and the cured overlay layer 46 is joined to the inner side surface of the outer steel plate 21. The cermet particles 45 are also preferable because they have not been recycled and the cermet chips, which have been conventionally treated as industrial waste, can be crushed into cermet particles, which can be effectively used.

Generally, 70 to 80% of the materials of cutting tools used in metal processing are cemented carbide tips, followed by cermets. Since tungsten is a rare metal in cemented carbide chips made of a sintered material containing tungsten carbide as a main component, various recycling methods have been put into practical use, and recycling is progressing.

On the other hand, since cermet is an extremely hard material, it is difficult to crush it, which is the main reason why recycling is not progressing. As the crushing method, a method in which a cermet chip and an explosive are collectively stored in water in a stainless steel container and crushed in water is expensive in crushing cost and the place of implementation is limited. Further, in the method using a stamp mill in which the cermet chips are housed inside the mortar and the cermet chips are crushed with a pestle, the particle size that can be crushed is limited and the processing time becomes long. Therefore, by crushing the recovered cermet chips with a dedicated crusher and classifying them with a vibrating sieve, it is possible to obtain desired classified cermet particles, and the recycled material in which the cermet chips are crushed is hard particles. Can be applied as.

When the hard layers 40 and 40A are formed on the outer steel plate 21, the inner side surfaces of the hard layers 40 and 40A are formed so as to be flush with the inner side surface of the steel pipe 10 forming the pumping pipe 50. Is preferable. With such a configuration, when the pressure-feeding material flows through the pressure-feeding pipe 50 formed by attaching the wear-resistant member 20 to the steel pipe 10, the smooth flow of the pressure-feeding material in the elbow portion can be guaranteed. Therefore, for example, when applying the steel pipe piece formed by the cutout when forming the cutout portion 13 of the steel pipe 10 to the outer steel plate 21, a process of scraping off a part of the inner side surface of the steel pipe piece is performed. By doing so, the total thickness of the outer steel plate 21 and the hard layers 40 and 40A when the hard layers 40 and 40A are formed is made to be about the same as the thickness of the steel pipe 10.

As shown in FIG. 1, the wear-resistant member 20 is arranged with respect to the notch 13 of the steel pipe 10, the first flange 14 and the second flange 22 are brought into contact with each other, and the corresponding insertion holes 14a, 22a and the insertion holes are inserted. By inserting bolts into 14b and 22b and tightening the nuts, the first flange 14 and the second flange 22 are firmly joined by the bolt nut 30 (an example of the fixing means) to form the pumping pipe 50. .. Here, the fixing means may be a plurality of clamps or the like in addition to the plurality of bolts and nuts 30 shown in the illustrated example.

Since the first flange 14 and the second flange 22 are fixed by bolts and nuts 30 (not shown), clamps (not shown), etc., both can be firmly joined, and at the time of maintenance or replacement of the wear-resistant member 20. The wear-resistant member 20 can be easily removed from the steel pipe 10, and the maintainability is also excellent. Further, of the steel pipe 10, only the portion that needs to be replaced is replaced because the wear resistant member 20 is replaceably attached to the high wear region 12a where the inner wall is relatively worn as compared with other parts. can do. Therefore, the maintenance cost can be significantly reduced as compared with the conventional pressure feed pipe which requires maintenance or replacement of the entire steel pipe 10. Since the wear-resistant member 20 has the hard layers 40 and 40A on the inner surface thereof, the maintenance period of the wear-resistant member 20 can be extended, which also reduces the maintenance cost. Contribute.

Further, as is clear from FIG. 1, both the steel pipe 10 and the wear-resistant member 20 are reinforced by the reinforcing ribs 15, 22, 23, so that the joints between the two are reinforced and the pressure-fed material is used. The impact resistance of the wear resistant member 20 against repeated impact loads is enhanced.

[Abrasion test]
The present inventors have manufactured a test piece in which three types of hard layers are attached to the surface of a steel plate, set each test piece on a rotary table of a low-load abrasive wear tester, and apply a load from above the test piece. A wear test was conducted to measure the amount of wear when the rotary table was rotated and slid in the attached state, and the amount of wear of each test piece was compared.

Here, in the test apparatus, abrasive grains made of silicon carbide (SiC) having a particle size of # 50 are applied to the mating material of the test body, and a load of 4.0 kgf (4.0 / 9.8 N) is applied to the test body. Was loaded, the rotation speed of the rotary table was set to 2500 rpm, and the test distance was set to 1.0 km.

The three types of hard layers are a hard layer made of a hardened cemented carbide material (HF800) made by crushing a cemented carbide chip (Comparative Example 1, hardness Hv is 740), and a hard layer made of a high-chromium cast iron material. (Comparative Example 2, hardness Hv is 690), and a hard layer made of a cured overlay material of cermet particles (in Example, hardness Hv is 1300 for the particle part and 350 for the welding material part). The test results are shown in FIG. 6, and in FIG. 6, the result of Comparative Example 1 is set to 1, and the ratio of Comparative Example 2 and Example to Comparative Example 1 is shown.

From FIG. 6, the wear amount of Comparative Example 1 is 1.0 and that of Comparative Example 2 is about the same as 1.05 (wear reduction), whereas the wear amount of Examples is 60% of that of Comparative Examples 1 and 2. It can be seen that the wear resistance of the hard layer made of the cured overlay material of the cermet particles is extremely excellent. From this result, it is proved that the maintenance period of the wear-resistant member 20 can be extended, and the maintenance cost is significantly increased in combination with the configuration that the pumping pipe 50 can replace only the part that needs to be replaced. It can be seen that it can be reduced to.

It should be noted that the configuration or the like described in the above embodiment may be another embodiment in which other components are combined, and the present invention is not limited to the configuration shown here. This point can be changed without departing from the spirit of the present invention, and can be appropriately determined according to the application form thereof.

10: Steel pipe, 11: Straight part, 12: Elbow part, 12a: High wear area, 13: Notch part, 14: First flange, 14a, 14b: Insertion hole, 15: Reinforcing rib, 20: Wear resistant member, 21: Main body (outer steel plate), 22: Second flange, 22a, 22b: Insertion hole, 23, 24: Reinforcing rib, 30: Bolt nut (fixing means), 40, 40A: Hard layer, 41: Cermet tip, 42: Welded layer, 45: Cermet particles, 46: Hardened overlay layer, 50: Pumped pipe

Claims (6)

A notch is provided in a high wear region where the inner wall of the steel pipe is relatively worn as compared with other parts, and a removable wear-resistant member is attached to the notch.
The wear-resistant member is a pumping pipe having an outer steel plate and a hard layer containing hard chips or hard particles formed on the inner surface of the outer steel plate. Around the notch on the outside of the steel pipe, a first flange is provided so as to project outward and surround the notch.
A second flange that projects outward and comes into contact with the first flange is provided on the outer outer circumference of the wear-resistant member.
The pumping pipe according to claim 1, wherein the first flange and the second flange are in contact with each other and are fixed by fixing means. The pumping tube according to claim 1 or 2, wherein the hard particles are cermet particles, and the hard layer is a cured overlay layer of cermet particles. The pumping pipe according to claim 1 or 2, wherein the hard tip is a cermet tip, and the hard layer is a welded layer of the cermet tip. The pumping pipe according to claim 3, wherein the cermet particles are a recycled material in which a cermet tip applied to a used cutting tool is crushed. The pumping pipe according to any one of claims 1 to 5, wherein the cutout portion is provided on the radial outer side of the elbow portion of the steel pipe.

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