JPS61178179A - Reflux blast device - Google Patents

Abstract

PURPOSE:To correct automatically the fluctuation of the state of blast particles projected repeatedly and maintain a uniform blast condition during a blasting process by inserting a wind force classifier comprising a zigzag passage in the return circuit of blast particles. CONSTITUTION:A wind force classifier 7 comprising a zigzag passage is inserted in the blast particle return circuit of a reflux blast device. A magnetic classifier 8 is inserted in a tail part line 9 where a tail substance classified at the zigzag passage of the wind force classifier 7 is taken out. a magnetized substance classified by said magnetic classifier 8 is discharged out of the system, while a non-magnetized substance is returned to the system. The wind force classifier 7 is utilized in that way, thereby making the adjustment and maintenance of repeatedly projected blast particles at a constant state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a recirculation blasting device that can automatically correct even if the morphology of blast particles changes during the operation of the device, and in particular, Multi-component blasting material (particles)
The present invention relates to a continuous blasting apparatus that can suitably achieve uniformity and homogenization of a coating when subjected to a coating forming treatment by blasting, such as forming a coating on the surface of an object to be treated.

[Conventional technology]

BACKGROUND ART Conventionally, circulation blasting apparatuses have been known that blast a workpiece while circulating blast particles, but in such apparatuses, the blast particles are worn out or denatured during circulation. Therefore, normally, the condition of the particles is observed and the blasting process is stabilized by replacing them with new particles or partially replenishing them with new particles.

Blasting is generally used to grind the surface of the object to be treated (for example, to remove rust), but in the case of such grinding, even a slight change in the shape of the two particles will rapidly reduce the effect. Since such occurrences are rare, strict control of the particle morphology so that it remains constant throughout the treatment has not normally been carried out.

However, when performing so-called mechanical blasting, in which the blasting material is deposited on the surface of the workpiece, the blasting conditions must be constant in order to achieve a homogeneous coating. Therefore, it is desirable that the particle size and properties of the blast particles to be projected remain constant during the process.

Japanese Patent Publication No. 59-9312 discloses a blasting material suitable for such mechanical blasting treatment. This is a particle that has an iron-zinc alloy layer around the iron core. When this particle is projected, the iron-zinc alloy layer moves from the particle to the surface of the workpiece, and this iron-zinc alloy Because it has high hardness and is brittle, and because the iron core with high specific gravity hits this iron-zinc alloy from the back, it forms an iron-zinc alloy with extremely high adhesion strength on the surface of the workpiece. A zinc alloy film can be formed.

The blasting equipment used to carry out the blasting process using such blasting materials is particularly required to have constant blasting conditions.

[Problem that the invention seeks to solve]

In a recirculation blasting device that repeatedly projects the blast particles after being projected onto the blasting zone, when it is desired that the shape of the blast particles that are repeatedly projected is always constant, the conventional device is used. However, it has not been possible to automatically adjust the morphology of such particles, such as particle size and particle quality, so that they remain constant throughout the blasting process.

The present invention attempts to solve such problems.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention is characterized in that, in a circulation type blasting device equipped with a blast particle circulation path, a wind classifier consisting of a zigzag passage is inserted into the blast particle circulation path. A magnetic classifier is inserted into the tail outlet line of the wind classifier, and the magnetically classified materials are discharged from the system while the non-magnetically attracted materials are returned to the system. The present invention provides a recirculation type blasting device.

Here, the wind classifier consists of a zigzag passage.

The material to be classified (
In a wind classifier in which particles (particles) are dropped into this passage, this passage is structured in a zigzag manner, and in accordance with the present invention, there are at least two or more turning points in this zigzag passage where the direction changes in a zigzag manner. Yes, the angle of this turning point is 45° or more and 120° or less,
The angle is preferably 100° or less, more preferably 90° or less. When inserting a wind classifier consisting of such a zigzag passage into the circulation line for blast particles, it is necessary to
It is preferable to install this zigzag passage vertically in the line where the particles fall so that the material to be classified (particles) descends from above this zigzag passage. Then, a passage is provided through which the air flowing from the bottom to the top of the zigzag passage exits from the zigzag passage. Since this passage is a passage through which the classified tail material is taken out, it is herein referred to as a "tail part outlet line". On the contrary, the passage from which the concentrate is removed, in fact the passage below the upper and lower zigzag passages, becomes the particle supply passage to the blasting zone.

In the device of the present invention, a magnetic classifier can be connected to the tail outlet line. In connection with this connection, it is preferable to select particles with a large particle size among the tail portions and then connect them to the magnetic classifier. For this sorting, it is preferable to provide means for causing an airflow carrying particles passing through the tail outlet line to flow obliquely upward, and for selecting large particles from this airflow and causing them to fall downward. The magnetic classifier itself may be a magnetic separator that selectively attracts magnetic particles to a rotor equipped with a magnet and collects the magnetic particles while separating them from other particles. The magnetic substances classified by this magnetic classifier can be discharged to the outside of the system, and the non-magnetic substances can be returned to the system for circulation use.

The details of the apparatus of the present invention will be specifically explained below according to the embodiments shown in the drawings.

〔Example〕

FIG. 1 is a diagram showing the entire equipment arrangement of the device of the present invention,
1 is a blasting zone, and 2 is a barrel for forming this blasting zone 1.

3 is a screw conveyor installed below this barrel 2, 4 is a packet elevator, 5 is a hopper path, and 6 is a rotor for projecting blast particles onto the blasting zone 1. Screw con hair 3. Packet elevator 4. The hopper path 5 forms a blast particle circulation path through which particles subjected to blasting are repeatedly projected from the rotor 6 again. 7 is a wind classifier consisting of a zigzag passage inserted into this blast particle circulation path,
8 is a magnetic classifier connected to the tail outlet line 9 of the wind classifier.

To configure the blasting zone l, a rotating endless perforated belt 10, for example as schematically shown in FIG. 2, is installed inside the barrel 3 of FIG. (For example, a bolt, a bolt, etc.) is rotated, and blast particles are projected from the rotor 2 toward the transferred workpiece 11. The blast particles that have been projected fall from the holes of the endless porous belt 10, and are transported laterally (
outside the barrel 2 in FIG. In the process of dropping the blast particles from the position where they are carried up by the packet elevator 4 to the rotor 6 by the drop to the rotor 6, a wind classifier 7 is inserted as shown in FIG.

FIG. 3 shows a portion of this wind classifier 7 in an enlarged manner. In FIG. 3, 13 is the outflow end of the blast particles from the packet elevator 4, and 14 is the supply end to the rotor 6. Between the head from the position 13 to the position 14, there is an inclined hopper path 5 and a zigzag path. A passage 15 is provided. That is, a hopper path 5 is provided which is inclined at an angle where the blast particles naturally flow down from the blast particle outflow end 13 from the packet elevator 4.
A zigzag passage 15 is connected vertically downward. At this time, the connection point between the hopper path 5 and the zigzag path 15 is formed into a three-way path, and an exhaust path 16 is provided diagonally upward from this connection point. This exhaust passage 16 becomes the previously described tail outlet line 9 (FIG. 1).

The hopper channel 5 has a blast particle inlet 1 with a lid 17.
8 is provided almost in the center, and a damper 19 is provided below.
is the installation. This damper 19 is a single-open Chatsuki damper with the support point 20 facing upward so that the lower ends of the nine blades open due to the weight of the particles. When this becomes large, the lower end of this damper 19 opens, and particles flow out from this opening. Therefore, this damper 19
This makes it possible to keep the flow rate of particles flowing downward constant while preventing backflow of air (flow of air in the opposite direction to the flow of particles).

The zigzag passage 15 is arranged in the vertical direction, and an air intake port 23 is provided below the zigzag passage 15, and an adjusted amount of air is supplied to the air intake port 23 from a blower 24 via a damper 25. . This air rises while changing direction at a conversion point in the zigzag passage 15 and is discharged to the exhaust passage 16 side. Air is preferably introduced into the zigzag passage 15 using a nozzle 26. This nozzle 26 may be provided in an air chamber 27 formed between the air intake port 23 and the air chamber 27 . In addition, zigzag passage 1
The air introduced into 5 is substantially not located below the zigzag passage 15. This is because particles accumulate in the nozzle portion falling toward the rotor 6 (this state is shown in FIG. 2), and these accumulated particles block the flow of air. When configuring the zigzag passage 15, at least two turning points are provided to change the direction in a zigzag manner, and the angle of the turning points is 45° or more and 120° or less, preferably 100° or less, and more preferably 90°. It is best to keep it below °.

FIG. 4 explains the relationship between the air flow (indicated by dotted lines) and the particle flow (indicated by solid lines) in this zigzag passage 15. The upwardly moving air crosses each inclined passage and collides with the opposing surface. The two particles change direction and rise in each inclined passageway.
It falls through the zigzag passage 15 while rolling up and crossing the airflow, and during this time it is divided into those that ride the airflow and are carried upwards, and those that do not ride the airflow and descend. Items that are carried along with the airflow have small particle sizes or light specific gravity, and items that fall against the airflow have low buoyancy (large specific gravity or large particle size). be. As a result, the original blast particle form descends in this zigzag passage 15, and particles damaged by the projection or fragments separated from one particle are carried towards the exhaust passage 16. Iron-
When using the blast particles described in Japanese Patent Publication No. 59-9312, which has a zinc alloy layer around an iron core.

The iron-zinc alloy layer is separated from the iron core by blasting, resulting in iron-zinc alloy powder, and the iron-zinc alloy layer has FJ loss, resulting in small particles with iron cores whose particle size has become smaller (
In the process of falling through this zigzag passage 15, the tail part) is carried by the airflow and selectively moves toward the exhaust passage 16,
It can be separated from healthy particles (the tail part is separated from healthy particles).

In this way, the air that accompanies the tail flows through the tail outlet line 9 (Fig. 1). However, in this embodiment, there is a secondary air flow along the tail outlet line 9. A wind classifier 30 is provided. This secondary classifier 30
As shown in Figure 3.

An opening 31 is provided in the lower plate of the exhaust passage 16 extending diagonally upward, through which particles with larger diameters among the tail portions selectively fall. Specifically, the exhaust passage 16 is also provided with a direction changing part 32 with which the airflow that has passed through the passage collides with the exhaust passage 16,
Particles flowing along with the airflow also collide with the wall of the airflow converter 32 to temporarily reduce their inertial energy, thereby removing particles that cannot ride the airflow that continues to flow downstream to the opening 31. to flow backwards toward the
In addition, particles that are entrained only up to the middle of the exhaust passage I6 are allowed to fall into the opening 31 in the middle of this passage, and one particle with a large particle size or one with a large specific gravity among the tail parts is selectively dropped from this opening 31. let In order to prevent the air flowing through the first passage 16 from leaking through the opening 31, the air is made to flow toward the third passage through the opening 31 as well. For this purpose, a branch air passage 33 is taken from the blower 24, a damper 34 for adjusting the air volume is interposed therein, and the branch air passage 33 is connected to an air chamber 35 provided below the opening 31. The air introduced into the air chamber 35 passes through the baffle plate 36.
and 37, while changing direction, passing through the opening 31 and being fed into the passage 16. In this way, by maintaining the inside of the air chamber 35 at a more positive pressure than the passage 16, the air flowing through the passage 16 from the opening 31 is prevented from leaking, and particles with a large size are removed from the opening 31. selectively taken out. Particles falling through this opening 31 are temporarily stored in a hoverer 38 and fall toward the magnetic classifier 8.

The magnetic classifier 8 has a large number of magnets 39 as shown in FIG.
By dropping particles from the hopper 38 onto this rotating drum 40, only magnetic particles are attracted to the magnet 39, and these are automatically collected. As a result, the particles are separated from the non-magnetic particles, and the non-magnetic particles are allowed to fall on the path 41 side, and the magnetic particles are allowed to fall on the path 42 side. In the case of blast particles having the iron-zinc alloy layer around the iron core, the non-magnetic particles collected on the side of the first passage 41 are substantially iron-zinc alloy, and the non-magnetic particles are substantially iron-zinc alloy.
The particles collected on the side of the passage 42 are those of iron cores whose iron-zinc alloy layer has been peeled off or consumed. The former is mixed with the particles projected into the blasting zone (mixed with the particles into the projection rotor 6), and the latter is discharged outside the system. 43 in FIG. 1 indicates iron particles discharged to the outside of the system.

The airflow flowing through the tail outlet line 9 and passing through the secondary classifier 3° is accompanied by fine particles. For this reason, the first
In the apparatus shown in the figure, a cyclone 44 and a bag filter 45 are installed downstream of the cyclone 44 to separate this fine powder from the air flow. The particles collected by the cyclone 44 are mixed with the particles projected into the blasting zone via a conduit 46.

Further, in order to circulate the air in the system, the suction side of the blower 24 is connected to the air passage 47 leading from the cyclone 44 to the bag filter 45, and the air flowing through this air passage 47 is sucked into the blower 24. This is then supplied to the wind classifier 7 and the secondary classifier 30 for classification.

〔effect〕

The recirculation blasting device of the present invention can maintain uniform blasting conditions while automatically correcting changes in the morphology of blast particles due to continued blasting. The apparatus of the present invention was loaded with blast particles (referred to as iron-zinc particles) having an iron-zinc alloy layer around the iron core described in Japanese Patent Publication No. 59-9312, and MIO bolts were used as the object to be treated. .

The effects will be specifically explained below by citing the operational results when the surface of this bolt is coated with an iron-zinc alloy.

As for the blasting conditions, 100 kg of the iron-zinc particles were charged from the rotor 6 into the last zone at a blasting rate of 60 m/sec and a blasting rate of 7, and continuous blasting was performed for 30 minutes. Then, the bolts of the object to be processed were replaced. The iron-zinc particles were repeated 10 times without replacing them. Therefore, the continuous treatment with these particles was carried out for 5 hours.

The blower 24 is 10n? /m1nX250mmAq
A device with a capacity of 0.75 to - was used, and the air speed and volume within the air device are as shown in Table 1.

Table 1 (a) to (h) in the table are the positions shown in FIG.

From the position downstream of each classifier during processing.

Particles in circulation were sampled every 10 minutes and their particle size distribution was measured. the result. The particle size of the particles originally used (
Particle size before classification) is +48 mesh; 34, 6%, 48
~60 meshes, 19.8%. 60-80 mesh; 16.3%. 80-100 mesh 7; 3.8%,
100-120 Mesos; io. s%. -120
mesh: It had a particle size distribution measurement value of 10.0%, but in the wind classifier 7. A concentrate of +60 mesh was collected with a classification rate of 94.5%, and a concentrate of 60 to 100 mesh was collected in the secondary classifier 30 with a classification rate of 96.4% in the hopper 38. In container 8, 1120 mesh fine powder was classified on the non-magnetized side at a classification rate of 92.8%. In addition, in the magnetic classifier 8, the classification ratio of magnetically attracted substances and non-magnetized substances was 88.8% for the former and 11.1% for the latter.

Then, as mentioned above, the 30-minute process was performed 10 times, that is, 5 times.
Although continuous time processing was performed, the same processing as at the beginning of the process could be performed at the end of the process. The bolt surface of the workpiece is covered with all kinds of surfaces such as grooves, valleys, and peaks. An extremely uniform iron-zinc alloy layer was formed, and there were no differences in quality due to differences in the location of the film or differences in processing time. A product of uniform quality with no difference in adhesion strength was obtained.

In this way, when particles made of two materials with different properties, iron and an iron-zinc alloy layer, are used as projectile particles, even though one of them is subjected to coating and is consumed, it is possible to obtain a uniform coating. It is a remarkable achievement that blasting conditions were maintained. This combines iron, which imparts physical energy during the shot, and a hard iron-zinc alloy layer, which serves as a coating layer. After projection, these are classified appropriately. This is thought to be due to the fact that the latter powder was returned to the system, which was a balanced process as a whole. In other words, the amount of iron-zinc alloy layer used in the coating is equal to the amount of iron particles discharged from the system. It is thought that the overall blasting conditions were maintained almost constant.

[Brief explanation of the drawing]

Fig. 1 is an overall equipment layout diagram of the recirculation type Plus 1 device of the present invention, Fig. 2 is an enlarged perspective view of the blasting zone, and Fig. 3 is an enlarged perspective view of the blasting zone.
The figure is a partially enlarged view of the wind classifier, FIG. 4 is a diagram showing the state of fluid flow in the wind classifier, and FIG. 5 is a diagram showing the principle of the magnetic classifier. 1; blasting zone; 2; barrel; 3; screw conveyor; 4; bucket elevator. 5; Hopper path, 6; Projection rotor, 7; Wind classifier, 8
；Magnetic classifier, 9; Tail part output line of wind classifier,
16; exhaust passage in the tail outlet line; 19; particle flow rate adjustment damper; 24; blower.

Claims (2)

[Claims] (1) A circulation blasting device equipped with a blast particle circulation path, characterized in that an air classifier having a zigzag passage is inserted into the blast particle circulation path. (2) In a circulation type blasting device equipped with a blast particle circulation path, a wind classifier consisting of a zigzag passage is inserted into the blast particle circulation path, and a magnetic classifier is connected to the tail outlet line of the wind classifier. 1. A recirculation blasting device characterized in that the magnetic material classified by the magnetic classifier is discharged from the system, and the non-magnetic material is returned to the system.