JPH11320413A - Scale removing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To high-efficiently and uniformly remove a scale, to reduce coarseness of the inner surface of a pipe to be ground after abrasive blasting, and to decrease an installation space for equipment. SOLUTION: In this scale removing equipment 1, a first high pressure injection blasting processing part 2 to apply blasting processing on the inner surface of one pipe end part of a steel pipe P, a second high pressure injection blasting processing part 3 to apply blasting processing on the inner surface of the other pipe end part of the steel pipe P; and a negative pressure suction blasting processing part 4 to apply negative suction type blasting processing on the inner surface of the overall length of the steel pipe P are arranged in juxtaposition. A delivering device for the steel pipe P is located between the blasting processing parts 2, 3, and 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a facility for removing scale adhered to the inner surface of a steel pipe after heat treatment by blasting. The present invention relates to a scale removing facility that can reduce the roughness of the inner surface and reduce the installation space of the facility.

[0002]

2. Description of the Related Art Steel pipes manufactured by various pipe manufacturing methods are:
Since the quality varies in the as-manufactured state, uniformity of quality, designation of standards or customers, correction of weaknesses during manufacturing, improvement of quality, reduction of added elements, simplification of processes, and necessity in manufacturing In general, heat treatment is performed for the purpose of properties. In the heat treatment of the steel pipe, the oxide scale adheres to the inner and outer surfaces of the steel pipe. Therefore, removing the scale from the steel pipe surface is important as one of the surface treatments of the steel pipe.

Conventionally, the removal of oxide scale adhering to the surface of a steel pipe by heat treatment has been conventionally carried out by immersing it in a pickling tank to remove it scientifically, by brushing it mechanically, or by containing powder and granules in high-pressure water. Although a physical method of spraying and removing the same has been performed, in recent years, for removing scale from the inner surface of a steel pipe, a blast process of colliding an abrasive material against the inner surface of the pipe has become common.

[0004] As blast processing, for example, sand blast, shot blast, grit blast and the like are mainly employed. In these blasting processes, iron, stainless steel, alumina, silica sand, or the like is used as a polishing material. For example, in the blasting process for oil country tubular goods having an inner diameter of 20 to 200 mm and a length of 5 to 15 m, either a method of injecting the abrasive material at a high pressure or a method of suctioning the abrasive material in a negative pressure state is adopted. doing.

[0005] A high-pressure injection type blast treatment is disclosed in, for example, a descaling method for the inner surface of a pipe disclosed in Japanese Patent Publication No. 54-42715. According to this method, as shown in FIG. 2, as shown in FIG. 2, the scavenging tube 22 is mounted on a roller 21 that is rotationally driven by a driving device (not shown), rotated, and supplied from a compressor 23. High-pressure air in the abrasive material tank 2
Then, the cleaning material is dropped and mixed in from the nozzle 4 and the nozzle 26 attached to the tip of the cleaning material transporting pipe 25 having an outer diameter smaller than the inner diameter of the cleaning pipe 22 is moved while moving in the longitudinal direction of the cleaning pipe 22. Injects a mixture of cleaning material and air to clean the cleaning material
This is done by colliding with the inner surface of No. 2.

A negative pressure suction type blasting process is disclosed in, for example, Japanese Patent Application Laid-Open No. Sho 60-263671. According to this method, scale removal is
As shown in FIG. 3, a supply unit 32 for supplying an abrasive material and negative pressure air for floating and transporting the abrasive material to one end of a pipe 31 to be polished.
And a receiver box 33 for separating the reusable coarse-grained abrasive material and the negative-pressure suction air containing the fine-grained abrasive material is connected to the other end of the scavenging pipe 31.
3 sequentially from the air suction direction in the suction direction of the air, using a device provided with a polishing material recovery means 34 having a cyclone separator, a dust collector 35, and a negative pressure suction unit 36 having an air suction means for sucking air. The cleaning material is moved by the compressed air in the cleaning target tube 31 to collide with the material.

[0007]

[Problems to be Solved by the Invention]
The high-pressure injection type blasting treatment as disclosed in Japanese Patent No. 42715 removes scale adhering to the inner surface of the scavenging pipe 22 while moving the nozzle 26 for injecting the abrasive in the longitudinal direction of the scavenging pipe 22. Therefore, if it is known in advance that the scale adhered to the inner surface of the scavenging tube 22 is not uniform, the moving speed of the nozzle 26 is controlled efficiently,
There is an advantage that the scale can be uniformly removed.

However, in the high-pressure injection type blasting, the length of the cleaning material transport pipe 25 is required to be substantially the same as the length of the cleaning pipe 22. In addition, there is a problem that the abrasive material remaining on the inner surface of the pipe must be removed by air blow or the like. In addition, there is also a problem that the surface roughness of the inner surface of the pipe after removing the scale becomes large, and the efficiency decreases during the production of crude oil in an oil well.

On the other hand, in the above-mentioned negative pressure suction type blast processing, since the abrasive material is floated and moved on the inner surface of the object to be cleaned 31 by negative pressure air, equipment can be installed in a small space. There is an advantage that the inner surface roughness of the blast pipe 31 after blasting is small.

However, in the negative pressure suction type blasting process, the sealability of the connecting portion is deteriorated due to the wear of the parts at the connecting portions of both ends of the scavenged pipe 31. As a result, scale removal at the pipe end becomes impossible. On the negative pressure suction side, there is a problem that the angle of collision of the blast material with the inner surface of the pipe 31 to be polished becomes small, so that the scale removing ability is lowered and the efficiency is also lowered. .

In the basic unit of the abrasive material used for the blasting process, in the case of the high-pressure injection type blasting process, as shown in FIG. In the case of the pressure suction type blast treatment, as shown in FIG. 5, not only the inner surface of the steel pipe (part A) but also the collision with the inner wall surface of the receiver box (part B) is broken.
Since the rate of reuse is reduced, there is also a problem that the basic unit of the abrasive material is deteriorated in the negative pressure suction type blasting process as compared with the high pressure injection type blasting process.

On the other hand, for example, in a steel pipe after heat treatment, oxidation easily proceeds at the both ends of the steel pipe because the air easily penetrates, and therefore, the thickness of the attached scale becomes thicker. However, what promotes the progress of oxidation is limited to the air staying inside the steel pipe, so that the oxygen concentration becomes thinner as the oxidation progresses, and it becomes difficult to promote the oxidation when the oxidation progresses to a certain extent. Therefore, in the central part of the steel pipe, if a certain scale thickness is generated, it tends to be difficult to further increase the thickness. Regarding the amount of scale attached to the inner surface of the steel pipe after heat treatment, the larger the inner diameter of the same material, the greater the amount of scale attached to the end of the tube, and the more easily oxidized material, the greater the amount of scale attached.

In the case where scale removal is performed on a steel pipe having such a tendency by high-pressure injection type blasting, the moving speed of the nozzle at the pipe end is reduced so that both pipe ends on the inner surface of the scavenged pipe, Shot energy corresponding to the scale thickness can be applied to the abrasive material at each central portion, so that the surface can be made uniform by blasting with relatively little loss.

However, in the case of the negative pressure suction type blast treatment, the shot energy applied to the polished material on the inner surface of the polished pipe decreases as it approaches the recovery side of the polished material. The time required for removal depends on the scale removal time of the pipe end on the recovery side of the abrasive material. Therefore, in the portion from the center of the pipe to be polished to be able to remove the scale at an early stage to the end of the pipe on the supply side of the lapping material, more shot energy than necessary is given to the lapping material. Cracks and the basic unit of abrasive material deteriorates.

In tests conducted to reproduce the above problems, for example, an outer diameter of 177.8 mm, a wall thickness of 11.51 mm,
As shown in FIG. 6, the inner surface of the 12 m long API standard L80-13Cr steel pipe after quenching and tempering has a pipe end of 0 to 4 m, and a pipe end of 10 to 12 m has a central part of 4 to 10 m.
m, the scale thickness was thicker.

For example, when a negative pressure suction type blasting process is performed on this steel tube under the conditions of an orifice diameter of 22 mm, three large blowers and one small blower at full output, and a cleaning time of 10 minutes, As shown in FIG. 7, the shot energy (also known as arc height) gradually applied to the abrasive material attenuates from the abrasive material supply side (pipe end 0 m) to the abrasive material recovery side (pipe end 12 m). did.

In addition, it took about 18 minutes for the scale to be removed by the negative pressure suction type blast processing so as to satisfy the quality. Therefore, in this test, as shown in FIG. 8, the middle portion of the steel pipe is easily descaled (6 to 1 until it is removed).
On the other hand, at the end of the pipe, especially on the abrasive material recovery side, it is difficult to remove the scale (18 minutes until it is removed). If the steel pipe is long, it takes time to remove the scale and the output for negative pressure suction is reduced. It turns out that it is necessary to increase. In FIG. 8, for example, 14 minutes after the start of scale removal, the scale remains at a position 350 mm from the recovery-side pipe end under the test conditions, that is, the scale at the recovery-side pipe end of the abrasive material is It turns out that it is difficult to remove.

That is, as shown in FIG. 9 (a), the negative pressure suction type blasting process has a large amount of useless shot energy, so that the efficiency is low. If the steel pipe is long, the scale cannot be effectively removed. On the other hand, in the high-pressure injection type blasting process, as shown in FIG. 9B, the injection pressure and the injection time can be partially adjusted, so that the scale can be efficiently and uniformly removed. However, it is necessary to lengthen the abrasive transporting pipe moving inside the steel pipe as described above, and the entire equipment becomes large. As described above, the high-pressure injection type blasting process and the negative pressure suction type blasting process each have advantages and disadvantages, and do not have both working efficiency and installation efficiency.

The present invention has been made in order to solve the above-mentioned problems, and makes use of these advantages while solving the problems of the high-pressure injection type blast processing and the negative pressure suction type. To provide scale removal equipment that can remove scale efficiently and uniformly, reduce the roughness of the inner surface of the blasted pipe after blasting, and reduce the installation space of the equipment. The purpose is to do.

[0020]

In order to achieve the above-mentioned object, a scale removing apparatus of the present invention removes scale on the inner surface of one end of a steel pipe in a first high-pressure injection blast processing section, and removes the scale on the other pipe. The first inner surface of the steel pipe is removed by the second high-pressure injection blast processing unit, and the scale of the central part of the steel pipe and the entire inner surface is removed by the negative pressure suction blast processing unit.
The high-pressure injection blast processing section, the second high-pressure injection blast processing section, and the negative pressure suction blast processing section were arranged in parallel, and a steel pipe transfer device was interposed between these processing sections. By doing so, the time required for scale removal can be shortened, the basic unit of the abrasive material can be improved, and the roughness of the inner surface of the steel pipe can be reduced.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A scale removing apparatus according to the present invention is a facility for removing scale adhering to an inner surface of a steel pipe, and a first high-pressure injection blast processing section for performing blast processing on an inner surface of one end of a steel pipe. And a second high-pressure injection blast processing unit for performing blast processing on the inner surface of the other end of the steel pipe, and a negative pressure suction blast processing unit for performing blast processing on the entire inner surface of the steel pipe are arranged in parallel, and between these blast processing units. A steel pipe transfer device is provided.

With the above configuration, in the first and second high-pressure injection blasting sections, the pipes for transporting the abrasive material have a length capable of moving by a predetermined amount with respect to one and the other end of the steel pipe. Space can be saved. In addition, after the scale removal of one and the other pipe ends is performed in the first and second high-pressure injection blast processing sections, the scale is finally removed in the negative pressure suction blast processing section over the entire length of the steel pipe. In addition, the scale of the entire steel pipe can be removed, the entire scale removal time can be reduced, and the surface roughness of the inner surface of the steel pipe can be reduced uniformly.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the scale removing equipment of the present invention will be described below with reference to FIG. FIG. 1 shows the descaling equipment of the present invention. The scale removing equipment 1 includes a first high-pressure injection blast processing section 2 that removes scale of the inner surface of one end P1 of the steel pipe P transported from the heat treatment step, and a steel pipe transported from the first high-pressure injection blast processing section 2. A second high-pressure injection blast processing section 3 for removing scale from the inner surface of the other pipe end P2 of P;
And a negative pressure suction blast processing unit 4 that removes the scale of the entire length of the inner surface of the steel pipe conveyed from the steel pipe.

First and second high-pressure injection blasting units 2;
Reference numeral 3 denotes, for example, abrasive material transfer pipes 2a and 3a which can move in predetermined ranges of one and the other pipe ends P1 and P2 of the steel pipe P.
Nozzles 2b, 3b provided at the downstream end of the blasting material transfer pipes 2a, 3a; blasting material tanks 2c, 3c provided at the upstream end of the blasting material transfer pipes 2a, 3a; Compressors 2d and 3d.

The negative pressure suction blast processing section 4 includes a gripping section 4a for gripping both ends of the steel pipe P in an externally fitting manner, and a polishing material supply section 4b provided at one end of the steel pipe P via the gripping section 4a. The receiver box 4c of the abrasive material provided at the other end of the steel pipe P via the gripping portion 4a and the downstream side of the receiver box 4c for separating the abrasive material from the removed scale and the broken abrasive material. A cyclone separator 4d, a dust collector 4e provided downstream of the cyclone separator 4d to collect the removed scale and broken abrasive, and a negative pressure generating air suction provided downstream of the dust collector 4e. Device 4f.

The scale removing equipment 1 includes a roller group 5 for positioning the steel pipe P conveyed from the heat treatment step at the installation position of the first high-pressure injection blast processing unit 2, and a first high-pressure A stopper 5a provided at the same position in the axial direction as the installation position of the injection blast processing unit 2 to align the steel pipe P, and the steel pipe P conveyed to the stopper 5a position is provided at the installation position of the first high-pressure injection blast processing unit 2. Transport means (transfer device) (not shown) for transporting to
It has a transport means (not shown) for moving the steel pipe P from the first high-pressure injection blast processing section 2 to a roller group 6 described later.

Further, the descaling equipment 1 is similarly provided with the second
A roller group 6, a stopper 6a, and a conveying means (not shown) for positioning the steel pipe P at a position where the high pressure injection blast processing section 3 is installed, and a steel pipe P from the second high pressure injection blast processing section 3 to the negative pressure suction blast processing section 4. Transport means (transfer device) (not shown) for transporting the image. The transfer means as a transfer device is configured to send the steel pipe P in a direction orthogonal to the transfer direction of the steel pipe P by the roller groups 5 and 6.

Next, the operation of the scale removing equipment 1 having the above configuration will be described. When the steel pipe P is transported to the roller group 5 from the heat treatment step, the steel pipe P is sent in the axial direction until the one pipe end P1 of the steel pipe P comes into contact with the stopper 5a by the roller group 5. Then, after the steel pipe P comes into contact with the stopper 5a, the steel pipe P is sent to the installation position of the first high-pressure injection blast processing unit 2 by a conveying means (not shown).

In the first high-pressure injection blast processing unit 2, the abrasive transfer pipe 2a having the nozzle 2b attached to the downstream end thereof is moved in the axial direction of the steel pipe P, and the nozzle 2b is inserted into the steel pipe P. When the compressed air is sent from 2d and the abrasive material is supplied from the abrasive material tank 2c to the abrasive material transfer pipe 2a, the abrasive material to which shot energy is given by the compressed air from the nozzle 2b is blown out. Is made to collide with the inner surface of the steel pipe P to remove the scale in a predetermined range of the one end P1 of the steel pipe P.

When the scale removal operation for a predetermined time is completed in the first high-pressure injection blast processing section 2, the steel pipe P is sent from the first high-pressure injection blast processing section 2 by a transport means (not shown) and transported to the roller group 6. You. Then, in the roller group 6, the steel pipe P is sent in the axial direction until the other pipe end P2 of the steel pipe P comes into contact with the stopper 6a, and the steel pipe P is transferred to the stopper 6a.
Is brought into contact with the steel pipe P by the transport means (not shown).
The high-pressure injection blasting unit 3 is sent to the installation position. The steel pipe P sent to the second high-pressure injection blast processing unit 3 is removed by the abrasive material in which a predetermined range of the scale of the other pipe end P2 of the steel pipe P is injected in the same manner as described above.

In the above-described scale removal in the first high-pressure injection blast processing section 2 and the second high-pressure injection blast processing section 3, the steel pipe P is fixed while the nozzles 2b and 3b are fixed to the shaft.
If the shaft is rotated, or if the nozzles 2b and 3b are rotated while the steel pipe P is fixed, the scale can be efficiently removed. The nozzles 2b and 3b and the abrasive transfer pipes 2a and 3a are movable by a certain amount in the axial direction of the steel pipe P.

In the second high-pressure injection blast processing section 3, the steel pipe P
When the scale removal at the other end of the steel pipe P is completed, the steel pipe P is transported to the negative pressure suction blast processing unit 4 by the transport means (not shown). In the negative pressure suction blast processing unit 4, both ends of the steel pipe P are gripped by the gripping parts 4a, and the inside of the steel pipe P is made airtight. In this state, the air suction device 4f is driven to make a negative pressure state inside the steel pipe P, When the abrasive material and the air for negative pressure suction are supplied from the abrasive material supply unit 4b, the abrasive material moves from one end to the other end while colliding with the inside of the steel pipe P to remove the scale on the inner surface of the steel pipe P. .

The abrasive material, the abrasive material broken by the collision of the inner surface of the steel pipe P, and the removed scale that have moved to the other end of the steel pipe P are captured by the receiver box 4c provided at the other end of the steel pipe P. Then, it is sucked by the cyclone separator 4d. In the cyclone separator 4d, a reusable abrasive material, that is, an abrasive material that did not crack by collision,
The abrasive material and scale broken by the collision are separated,
Of these, the reusable abrasive material is returned to the abrasive material supply unit 4b. On the other hand, the broken abrasive and scale separated by the cyclone separator 4d are separated by the dust collector 4e.
Is captured by

Next, the effect of the above-described scale removing equipment 1 will be described. Table 1 below shows that, after heat-treating a 13% Cr oil well steel pipe P having an outer diameter of 177.8 mm, a wall thickness of 11.51 mm, and a length of 12 m, the scale was removed using the scale removing equipment 1 and the high pressure injection was performed. The following shows the results of comparison of the scale removal status, the basic unit of abrasive material, and the surface roughness after scale removal when the scale was removed only by the blast treatment of the formula and when the scale was removed only by the blast treatment of the negative pressure suction type.

[0035]

[Table 1]

As shown in Table 1, when the steel pipe P was descaled by the descaling equipment 1, the time required for the blasting process using only the high-pressure injection type and the blasting process using the negative pressure suction type was shorter. 100% of the scale could be removed, the basic unit of the abrasive material could be reduced, and the surface roughness after removing the scale could be reduced.

As described above, in view of the fact that a large amount of scale adheres to both ends of the steel pipe P after the heat treatment, the scale removing equipment 1 partially reduces the shot energy given to the abrasive material in the steel pipe P. Utilizing the advantages of high-pressure injection type blasting that can be controlled in a controlled manner, descaling of both ends of steel pipe P is performed, and descaling of only one end and the other end of steel pipe P is sequentially performed by high-pressure injection blasting. As a result, the abrasive transfer pipe can be shortened,
In addition, the size of the second high-pressure injection blast processing units 2 and 3 can be reduced.

Further, the scale removing equipment 1 has the first blast processing section 2, the second blast processing section 3, and the negative pressure suction blast processing section 4 arranged in parallel as described above, and performs the first and second high pressure injection blast processing. The scale of the one end P1 and the other end P2 of the steel pipe P is removed by the parts 2 and 3, and finally, the entire length of the steel pipe P is removed by the negative pressure suction blast processing part 4. Therefore, the surface roughness of the inner surface of the steel pipe P after the scale removal can be reduced.

Further, a disadvantage in the negative pressure suction type blasting process, that is, at one end of the steel pipe P (on the side where the abrasive is supplied), an excessive amount of shot energy is given to the abrasive and on the other end (on the side where the abrasive is collected). The first and second high-pressure injection blasting units 2 and 3 compensate for the disadvantage that the shot energy given to the abrasive material is insufficient, so that uniform scale removal is possible and the negative pressure suction In addition to the fact that the type blast processing unit 4 itself can install equipment in a small space, the first and second high-pressure injection blast processing units 2 and 3 can be downsized as described above.
As a whole, an increase in the size of the equipment can be suppressed.

The scale removing equipment of the present invention is not limited to the above embodiment, but can be modified. For example, the roller groups 5, 6 and the stoppers 5a, 6a in the above embodiment may be omitted to provide one.
First and second high-pressure injection blasting units 2 and 3 are disposed at both ends of one roller group, and a steel pipe P mounted on the roller group is disposed.
Is moved to one end of the roller group, and the scale is removed at the one end P1 of the steel pipe P by the first high-pressure injection blast processing unit 2. Then, the steel pipe P is moved to the other end of the roller group to remove the scale. If the scale of the other end P2 of the steel pipe P is removed by the high-pressure injection blasting section 3, the entire installation space can be reduced.

[0041]

As described above, the scale removing equipment of the present invention removes the scale of one end and the other end of the steel pipe in sequence by the first and second high-pressure injection blasting sections, and then reduces the entire length of the steel pipe to a negative pressure. Since these processing units are laid out in parallel so as to remove the scale in the suction blast processing unit, the scale can be removed reliably in a short time. Further, the scale removing equipment of the present invention can shorten the abrasive material transfer pipe by removing the scale only at the pipe end in the first and second high-pressure injection blast processing sections,
Therefore, these installation spaces can be reduced.

Further, the scale removing equipment of the present invention mainly removes the scale at the central portion of the steel pipe in the negative pressure suction blast processing section. As compared with the suction force, the suction force can be reduced to a small negative pressure. Therefore, it is possible to prevent the abrasive material from being cracked and becoming a reuse load, thereby improving the basic unit of the abrasive material. Moreover, since the scale removing equipment of the present invention finally removes the scale of the inner surface of the steel pipe by the negative pressure suction blast processing section, the surface roughness of the inner surface of the steel pipe after the scale removal can be reduced uniformly.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a scale removing facility of the present invention.

FIG. 2 is a view showing a conventional high-pressure injection type blasting scale removing apparatus.

FIG. 3 is a diagram illustrating a conventional scale removing apparatus by negative pressure suction type blast processing.

FIG. 4 is a view showing a state in which a polishing material collides with the inner surface of a steel pipe in a conventional scale removing apparatus by blast processing of a high-pressure injection type.

FIG. 5 is a view showing a situation in which a polishing material collides with an inner surface of a steel pipe and an inner wall surface of a receiver box in a conventional scale removing apparatus using a negative pressure suction type blasting process.

FIG. 6 is a diagram showing the relationship between the position of a steel pipe and the scale adhesion thickness.

FIG. 7 is a diagram showing a relationship between a position of a steel pipe and a shot energy of a polishing material in a conventional negative pressure suction type blasting scale removing apparatus.

FIG. 8 is a diagram showing the relationship between the length of a steel pipe and the time required for scale removal in a conventional vacuum removal type blasting scale removing apparatus.

9A is a diagram showing a relationship between a position of a steel pipe and a shot energy of a polishing material in a conventional scale removing apparatus using a negative pressure suction type blasting process, and FIG. 9B is a diagram showing a conventional high pressure injection type blasting process. It is a figure which shows the relationship between the position of a steel pipe, and the shot energy of an abrasive material in the scale removal apparatus by a blast process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Scale removal equipment 2 1st high pressure injection blast processing part 3 2nd hole thickness injection blast processing part 4 Negative pressure suction blast processing part P Steel pipe

Claims (1)

[Claims] 1. A facility for removing scale adhering to an inner surface of a steel pipe, comprising: a first high-pressure injection blast processing section for performing blast processing on an inner surface of one pipe end of a steel pipe; A second high-pressure injection blast processing unit that performs blast processing, and a negative pressure suction blast processing unit that performs blast processing on the entire inner surface of the steel pipe are arranged in parallel,
A scale removing facility comprising a steel pipe transfer device interposed between these blasting sections.