JP2002187068A - Suction type abrasive cleaning device and the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a suction type abrasive cleaning device and the method, which reduce wear of particle collectors and powdering of particles. SOLUTION: The suction type abrasive cleaning device serves to clean inside of a pipe to be cleaned, by sucking inside air from an end of the pipe together with an abrasive material which is sucked from another end of pipe, and serves to collect the abrasive material into a particle settling device which is located on the downstream in passing direction of the abrasive material in the pipe, besides provides a means of dropping the particles from above the particle settling device. It is desirable that the particle settling device is a receiver box.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to industrial pipes, tubes, architectural pipes and the like (hereinafter, also simply referred to as pipes).
Suction-type blasting device used for blasting the inner surface of a pipe, and in particular, a suction-type blasting device and a method thereof capable of suppressing the pulverization of blast particles generated during the blasting of a pipe inner surface About.

[0002]

2. Description of the Related Art Generally, methods for descaling the inner surface of a pipe can be roughly classified into 1) high-pressure blowing method and 2) suction method.

[0003] In the high-pressure blowing method, a cleaning material injection nozzle is inserted into a pipe to be polished, and the cleaning material particles injected together with the high-pressure gas from the nozzle collide against the inner wall of the pipe, thereby cleaning and removing the inner surface of the pipe. This is a method for performing scaling.

[0004] However, this high-pressure blowing method requires a large amount of power cost because high-pressure gas is required, and also has a problem in that the blowing equipment is also compatible with high-pressure gas, so that equipment costs are also increased.

Further, since the nozzle or the pipe to be polished needs to be moved over the entire length of the pipe to be polished, there is a problem that the equipment becomes complicated. As a method for solving such a problem, a suction method has been proposed.

For example, JP-A-6-2700065 proposes that secondary air is sucked from the end of a pipe and the secondary air is swirled to efficiently remove the scale.

[0007] In this method, a cyclone and a bag filter are assumed as a recovery system for the abrasive and scale (hereinafter also referred to as abrasive particles or simply particles).

[0008]

Since the finely-ground abrasive particles easily follow the movement of the gas flow, the probability of collision with the wall of the abrasive pipe is reduced. Further, even if a collision occurs, the impact force becomes small because the abrasive particles are small and light. As a result, when the abrasive particles containing a large amount of fine powder are used, the abrasive ability is reduced when compared with the same particle supply mass. Further, if a large amount of fine powder is contained, a shelf may be suspended in the hopper for supplying the abrasive particles, and supply failure may occur.

In order to solve these problems, the fine powder portion in the abrasive particles is discharged and discarded outside the system. On the other hand, the promotion of the pulverization of the abrasive particles means that the amount of the abrasive particles discharged and discarded outside the system increases, which directly increases the polishing treatment cost.

Therefore, the abrasive particles collide with the inner wall of the particle sedimentation device such as the receiver box or cyclone,
It is desirable that breakage (hereinafter also referred to as powdering) be prevented as much as possible.

[0011] For example, a cyclone is a particle sedimentation device that uses a centrifugal force to separate abrasive particles and carrier gas. The principle is that a mixture of abrasive particles and carrier gas is introduced in the tangential direction of the cyclone, a swirling flow is induced in the container, and the abrasive particles collide with the container wall by centrifugal force to collect the particles. Based on That is, the blast particles sufficiently accelerated in the blast tube collide with the cyclone wall without deceleration.

Generally, abrasion due to particles has a particle velocity of 2.5 to 3
[For example, Powder Transportation Technology, Takeshi Kano, Nikkan Kogyo Shimbun, October 1991, first edition, 308 pages
When the collision speed is high, the cyclone wall surface is liable to be worn, and the abrasive particles are liable to be powdered.

As another method for separating the abrasive particles from the carrier gas, there is a method utilizing gravity or inertial force. Particle sedimentation devices that use inertial force apply a mixture of blast particles and carrier gas to some kind of baffle plate (collision plate, guide plate)
To collect particles. In other words, the abrasive particles advance in the direction of the baffle plate due to a large inertial force, but the carrier gas has a small inertial force so that the direction can be changed, and as a result, the abrasive particles and the carrier gas respectively travel in different directions. The abrasive particles and the carrier gas are separated. Also in this case, the abrasive particles collide with the stationary baffle plate without deceleration, so that abrasion of the collision plate and powdering of the particles are inevitable.

As a countermeasure, there is a method of suppressing abrasion and powdering of the apparatus by attaching a wear-resistant material such as a wear-resistant rubber plate to a baffle plate. However, it is necessary to periodically replace the wear-resistant material. However, there is a problem that the operation rate of the device is reduced.

A particle sedimentation device utilizing gravity utilizes a difference in density between the carrier gas and the particles and introduces a mixture of the carrier gas and the particles into a container having a large cross-sectional area perpendicular to the flow direction. The average particle velocity is reduced so that the particles are not suspended by the carrier gas and the particles are collected.
In other words, the carrier gas is exhausted from above the receiver, but the particles have a large inertial force and cannot change direction as freely as the carrier gas, so they collide with the opposite side wall surface of the scavenging pipe connection at a high speed. . As a result, abrasion of the wall surface and powdering of particles occur.

An object of the present invention is to provide a suction-type blasting apparatus and a method thereof which can reduce abrasion of the particle collecting apparatus for collecting particles and powdering of the particles.

[0017]

The present inventor has conducted the test using a gravity-type receiver, and has obtained the following findings. In addition, a mixture of carrier gas and particles is introduced from the side of the receiver, the separated carrier gas is discharged from above, and the particles settled by gravity are discharged from below to the outside of the receiver, and recycled as abrasive material. Hereinafter, the scavenging material is also referred to as collected particles.

(A) Particles are chipped or cracked when the force acting on the particles when the particles collide with a baffle plate, the wall surface of a receiver, or the like exceeds the mechanical strength of the particles. It will go.

(B) The force acting on the particles when they collide is proportional to the change in momentum of the particles, and is inversely proportional to the time required for the change. The change in momentum and the acting force are smaller in the case of hitting an object that is easily moved by collision than in the case of hitting the wall of a baffle or a receiver. That is, the force due to the collision is represented by the following equation. (Force due to collision) = (change in momentum) / (time required for change) Stretching the rubber plate has an effect of increasing the time required for change, and reduces the force due to collision. Colliding with an object that moves easily due to a collision reduces the change in momentum and reduces the collision force.

Therefore, instead of the method in which the particles coming from the scavenging tube collide with the receiver wall surface, the collected particles are allowed to fall freely from the upper part of the receiver, and the collected particles collide with the conveyed particles. , And powdering can be suppressed.

Of course, even if abrasive particles and / or other particles are used as the colliding particles, the speed can be effectively reduced and powdering can be suppressed. As other characteristics of the particles, the particle mass is desirably about the same as or less than the abrasive particles, and the particle hardness is desirably the same as or less than the abrasive particles. For example, sand, quartz sand and the like can be used.

However, by employing recovered particles as the colliding particles, there is an advantage that equipment for newly producing / supplying the colliding particles and a recovery facility are unnecessary. Here, there is no substantial reduction in the particle separation performance due to returning the particles. That is, the particle separation performance of the receiver is determined by the carrier gas flow velocity of the carrier gas exhaust pipe from the receiver, but returning the collected particles to the receiver does not increase the velocity of the carrier gas exhausted from the receiver. There is no performance degradation.

The present invention has been made based on the above findings, and the gist is as follows. (1) The internal air is sucked from one end of the scavenging pipe to be scrubbed, and the inner surface of the scavenging pipe is scrubbed by using the scavenging material sucked from the other end of the scavenging pipe. In a suction-type blasting device that collects the blasting material in a particle sedimentation device disposed on the downstream side of the blasting material in the direction in which the blasting pipe passes, it is preferable that the device has means for dropping particles from an upper part of the particle sedimentation device. Characteristic suction-type cleaning device.

(2) The internal air is suctioned from one end of the scavenging tube, and the inner surface of the scavenging tube is cleaned using the cleaning material sucked from the other end of the scavenging tube. A suction-type blasting device that collects the blasting material in a particle sedimentation device disposed on the downstream side of the blasting material in the direction in which the blasting pipe passes, wherein the blasting material deposited under the particle sedimentation device; Characterized by having means for dropping from the upper part of the particle sedimentation device.

(3) The suction type cleaning apparatus according to the above (1) or (2), wherein the particle sedimentation device is a receiver box. (4) The internal air is suctioned from one end of the scavenging tube to be scrubbed, and the inner surface of the scavenging tube is scrubbed using the scrubbing material sucked from the other end of the scavenging tube. In a suction-type blasting method for recovering the blasting material to a particle sedimentation device disposed on the downstream side of the blasting material in the direction of passage of the blasting pipe, particles are dropped from an upper part of the particle sedimentation device. Cleaning method.

(5) The internal air is suctioned from one end of the scavenging tube, and the inner surface of the scavenging tube is cleaned using the cleaning material sucked from the other end of the scavenging tube. A suction-type wiping method for collecting the blast material in a particle sedimentation device disposed on the downstream side of the blast material in the direction in which the blasting pipe passes, wherein the blast material deposited under the particle sedimentation device; Is dropped from the upper part of the particle sedimentation device.

(6) The cleaning method according to the above (4) or (5), wherein the particle sedimentation device is a receiver box.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION As a sedimentation device for separating and recovering particles, a cyclone, a receiver box or the like can be used.

FIG. 1 is a conceptual diagram showing a configuration example of a suction-type polishing apparatus of the present invention. As shown in the figure, the abrasive material 2 mounted on the abrasive material hopper 1 is discharged to the suction pipe 4 via the abrasive material cutting device 3 and is blown by a blower 8 serving as a power source for suction. The gas is accelerated together with the suction gas from the suction pipe 4 and supplied to the scavenging tube 5. A receiver box 6 is provided at the exit side of the scavenged pipe 5 to collect coarse particles (abraded material and scale), and fine particles are collected by a bag filter 7.

As one configuration example of the present invention, a means for dropping the collected particles collected at the bottom of the receiver box 6 from the upper part of the receiver box is required. Means for dropping the collected particles from the upper part of the receiver box include a collected particle cutting device 9, a conveying device 10 for spraying, and a hopper 1 for spraying.
A part of the collected particles collected by the receiver box is cut out by the collected particle cutting device 9, conveyed to the spraying hopper 11 by the spraying conveying device 10, and sprayed. Cutting device 12
And sprayed from the top of the receiver box.

As the spraying and cutting device 12, for example, a screw feeder or a vibration feeder can be used. For example, a chain conveyor, a bucket conveyor, or the like can be used as the spraying transport device 10.

A part of the particles collected by the receiver box 6 is returned to the abrasive hopper 1 via the abrasive transport device 13 and reused. In addition, when using the abrasive material and / or other particles as the particles for spraying, the abrasive material and / or other particles are charged into the hopper 11 for spraying, and the cutting-out device 12 for spraying is used. What is necessary is just to drop the particles into the receiver box 6.

[0033]

EXAMPLES Test results when 100 steel pipes having an inner diameter of 154.8 mm and a length of 10 m were treated are shown below (the basic process is as shown in FIG. 1). The test conditions were as follows: supply rate of abrasive particles: 19 kg
/ min, cleaning time: 15 min / line, suction gas amount: 130 Nm ³ / min.

Table 1 shows the results of the examples performed in the following manner. The powdering ratio in the table is the ratio of the total mass (28500 kg) of the abrasive material used for the blasting to the mass discharged after being powdered and discharged out of the particle sedimentation apparatus.

The stoppage time is the total time required for repair / inspection of the equipment when each test equipment has been operated for one week.

[0036]

[Table 1]

(Conventional Example 1) A gravity type receiver box is used as a particle sedimentation device, and the depth of the receiver box is
It was 1.5 m. Since the mass discharged outside the system of the particle sedimentation device after the treatment was 1055 kg, the powdering ratio was 3.7%. In addition, in a continuous operation for one week, a hole was formed in the portion where the particles collided in the receiver box, so that the portion had to be repaired.

(Conventional Example 2) A cyclone was used as a particle sedimentation apparatus. The cyclone diameter was 1 m. Since the particles are incident tangentially to the cyclone, the state of collision between the cyclone and the particles is alleviated as compared with the receiver, and the mass discharged outside the system of the particle sedimentation device after the treatment was 855 kg. The powdering ratio was 3.0%. In addition, during one week of continuous operation, the cyclone was perforated, so repairs were necessary. In addition, the cyclone had to be replaced to accommodate samples with different diameters of the scavenged pipe. Time was needed. (Example of the Present Invention) A gravity-type receiver box was used as a particle sedimentation apparatus, and the depth of the receiver box was 1.5 m.
In addition, a part of the collected particles collected by the receiver box was dropped from above at a supply speed of 19 kg / min. Since the mass discharged out of the system of the particle sedimentation device after the treatment was 428 kg, the pulverization ratio was 1.5%, which was halved compared to the conventional example 1 or 2. In addition, the continuous operation for one week did not cause any holes in the receiver box, and only stopped for a short period of time for periodic inspection.

Even when the abrasive was dropped at the same supply speed in place of the recovered particles, the powdering ratio was about 1.5%, which was similarly halved as compared with Conventional Examples 1 and 2.

[0040]

According to the present invention, since the powdering rate can be reduced, the shot cost can be reduced.
In addition, productivity can be improved because the stoppage time can be reduced.
Furthermore, equipment maintenance costs could be reduced, and costs could be reduced.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a configuration example of a suction type polishing apparatus of the present invention.

[Explanation of symbols]

 1: Hopper for blasting material, 2: blasting material, 3: blasting material cutting device, 4: suction pipe, 5: polished tube, 6: receiver box, 7: bag filter, 8: blower, 9: Collected particle cutting device, 10: Spraying conveying device, 11: Spraying hopper, 12: Abrasive material hopper, 13: Abrasive material conveying device.

Claims (6)

[Claims] An internal air is suctioned from one end of a scavenging pipe to be scrubbed, and an inner surface of the scavenging pipe is scrubbed using a scrubbing material sucked from another end of the scavenging pipe. A suction-type blasting device that collects the blasting material in a particle sedimentation device disposed on the downstream side of the blasting material in the direction in which the blasting pipe passes, the device having means for dropping particles from above the particle sedimentation device. A suction type cleaning apparatus characterized by the above-mentioned. 2. An internal air is sucked from one end of the scavenging tube to be scrubbed, and the inner surface of the scavenging tube is scrubbed by using a scrubbing material sucked from the other end of the scavenging tube. A suction-type blasting device that collects the blasting material in a particle sedimentation device disposed downstream of the blasting material in the direction in which the blasting pipe passes, wherein the blasting material deposited under the particle sedimentation device is removed. A suction-type cleaning device comprising means for dropping from the upper part of the particle sedimentation device. 3. The suction type cleaning apparatus according to claim 1, wherein the particle sedimentation device is a receiver box. 4. An internal air is suctioned from one end of the scavenging tube, and the inner surface of the scavenging tube is cleaned by using an abrasive material sucked from the other end of the scavenging tube. A suction-type blasting method for collecting the blast material in a particle sedimentation device disposed downstream of the blast material in a direction in which the blast material passes through the blasting pipe, wherein particles are dropped from an upper part of the particle sedimentation device. And the cleaning method. 5. An internal air is sucked from one end of the scavenging tube to be scrubbed, and an inner surface of the scavenging tube is scrubbed by using a scrubbing material sucked from the other end of the scavenging tube. A suction-type blasting method for collecting the blasting material in a particle sedimentation device disposed downstream of the blasting material in a direction in which the blasting pipe passes, wherein the blasting material deposited at a lower portion of the particle sedimentation device is removed. A polishing method comprising dropping from the upper part of the particle sedimentation device. 6. The cleaning method according to claim 4, wherein the particle settling device is a receiver box.