JPH10128666A - Air blast device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air blast device of simple structure with a small harmful effect by static electricity even by using an easily charged projection material of resin or the like. SOLUTION: In an air blast device applying blasting work to a treated objet by a projection material to collect it to a hopper 3 through a projection material recovery circuit circulated and utilized, of the projection material recovery circuit, in a part just before the hopper, a low speed transfer feed path of screw conveyer 21 or the like, transfer feeding at a low speed while rolling a flow of the projection material transfer fed to the hopper 3, is provided, the transfer fed projection material is brought into contact with a static eliminator means consisting of metallic material of an earthed helical blade 23 in this feed path, pipe-shaped outer wall 28, or the like, and the projection material is made antistatic just before the hopper in the halfway of a transfer feed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air blasting apparatus in which a blasted blasted material to be processed is collected in a hopper through a blasted material recovery path and is recycled for use. TECHNICAL FIELD The present invention relates to an improved air blast device capable of reducing the adverse effects caused by electrification of a blast material even when blasting is performed using the blasting method.

[0002]

2. Description of the Related Art A blasting material is accelerated by the jetting force of compressed air to collide with an object to remove burrs and scales of the object, and the blasted blasting material passes through a blasting material recovery path. Air blast devices that are collected in a hopper and recycled are widely used because they can process a large number of articles with complicated shapes. If you try to treat a small article with a resin-made projectile that is easily charged with static electricity, the projectile is charged with static electricity, causing clogging inside the pipe, or attaching to the surface of the object to be treated, requiring a great deal of labor to remove it. There were various problems.

In order to solve such a problem, Japanese Utility Model Laid-Open No.
Focusing on the point that static electricity is generated due to friction between accelerated projectiles as seen in JP-A-5-23952,
In order to suppress the generation of static electricity by coating the blasting material with a static electricity removing liquid, spray means for spraying a static electricity removing liquid such as water with a surfactant added in the air pipe close to the nozzle to eliminate the adverse effects of static electricity Although an air blast device has been proposed, even if the generation of static electricity is suppressed by such a device, the effect does not last for a long time, and there is a problem that the effect is uneven, and the air blast device has a problem. It is difficult to remove the lost static electricity. Therefore, a method of removing the generated static electricity to further reduce the adverse effects caused by the static electricity has been attempted. For example, a conventional method of disposing a contact neutralizing means such as a grounded chain in a projection chamber has the effect. Was not enough. That is, in the conventional air blast device, a cyclone as dust separating means for separating dust and a blast material transported by a dust collection airflow is disposed above the hopper, and the blast material stalled by the cyclone is directly deposited on the hopper. When the static eliminator is arranged in the blast material flow path, the projectile is accelerated at a high speed in the static eliminator, and it is established that the projectile moving at a high speed contacts the grounded metal part. In addition to being not very high, even if the charge is removed, the projectiles immediately collide again and become charged, so that a sufficient charge removal effect could not be expected.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems by simplifying a structure which is less harmful to static electricity even if a projectile material such as resin which is easily charged is used. To provide a suitable air blast device.

[0005]

SUMMARY OF THE INVENTION An air blasting apparatus according to the present invention, which has been made to solve the above-mentioned problems, collects and circulates a blast material on which an object is blasted, through a blast material collecting path to a hopper. In the air blasting device that is used, a low-speed transfer path that transfers at low speed while rolling the flow of the blast material transferred to the hopper is provided in a portion of the blast material collection path immediately before the hopper, and the low-speed transfer path is provided in the low-speed transfer path. Is characterized in that a static eliminator made of a grounded metal material is provided to eliminate static electricity in contact with the projected material to be transferred.

In the above-described air blasting apparatus, the grounded metal member is provided in a low-speed transfer path of the blast material recovery path, and is provided in a temporary storage tank for collected blast material provided immediately before the low-speed transfer path. The invention according to claim 2 is a metal screw conveyor connected to a hopper, and in these air blast devices, an antistatic liquid is supplied to a compressed air flow path portion for accelerating a blast material and ejecting the blast material from a nozzle. The invention according to claim 3 is provided with a spraying means of the present invention. Further, a dust separating means for separating dust and a blast material transferred by a dust collection air flow is provided in the middle of the blast material collecting path, The invention according to claim 4 is provided with a means for spraying an antistatic liquid on the inlet side of the separating means.

[0007] In the air blasting apparatus configured as described above, the collected blast material sent through the blast material collecting path is sufficiently decelerated in the low-speed transfer path provided immediately before the hopper, and is transferred while rolling. As described above, the charge is neutralized by contacting the grounded metal part, so that the charge is uniformly and accurately removed, and the shot material once discharged is stored in the hopper without being charged again. In particular, if the collected blast material is temporarily stored in a temporary storage tank and then transferred to a hopper by a grounded screw conveyor, the transfer and static elimination can be performed by one screw conveyor, which is more efficient. When the spraying means of the antistatic liquid is provided in the compressed air flow path for accelerating the material and ejecting it from the nozzle, it is possible to suppress the generation of static electricity at the time of spraying, and it is also possible to prevent the spray material from being collected. If dust separation means is provided on the way to separate dust and blasted material transported by the dust collection air stream, and an antistatic liquid spraying means is provided on the inlet side of the dust separation means, the static electricity generated during collection may be reduced. Since the generation can be suppressed, the adverse effects of static electricity can be reduced through the entire blast material collection path, which is more preferable.

[0008]

Next, preferred embodiments of the present invention will be described in more detail with reference to the drawings. Reference numeral 1 denotes an air blast device main body.
A hopper 3 into which the projectile 2 is loaded is provided on the ceiling of the projection chamber 10, and the electromagnetic valve 4 is connected to a lower projecting material outlet located inside the projection chamber 10. Is connected to a nozzle 6 through a flexible hose 5 and connected to the nozzle 6 with a compressed air pipe 7 to which compressed air is supplied from outside via an antistatic spraying means 8. Further, on the side wall of the projection chamber 10, there is provided an air inlet 11 for introducing the air 9, which is a transfer medium of the projection material 2 scattered in the projection chamber 10 and the generated dust, and The bottom is squeezed in a funnel shape and connected to an exhaust pipe front section 12. The exhaust pipe front section 12 is connected to spray means 13 for spraying an antistatic agent by compressed air supplied from a compressed air supply pipe 14. The spraying means 13 is located at the rear of the exhaust pipe. The cyclone 16 is connected to the cyclone 16 via the air passage 5, and the cyclone 16 functions as dust separating means for separating the dust and the blast material transported by the dust collection airflow in the middle of the blast material collection path. Are separated, dust is collected in a dust collector not shown in the drawing connected to the dust collection pipe 17, and the blast material is configured to fall into the blast material collection unit 18 below the cyclone 16.

A projectile collecting section 18 below the cyclone 16 is connected to a vibrating sieving machine 19 so that foreign matter is deposited on a dust box 20 and the projectile 2 is moved to a temporary storage tank 21. A screw conveyor 22 is provided upright on the temporary storage tank 21. The screw conveyor 22 has one end of the spiral blade 23 facing the temporary storage tank 21, and the other end of the spiral blade 23 is connected to a motor 24 via a speed reducer 25. Is designed to be driven to rotate. A projectile discharge pipe 26 is branched from the tubular outer wall 28 of the screw conveyor 22, and the other end of the projectile discharge pipe 26 faces the inside of the hopper 3.

Next, the operation of the air blast device configured as described above will be described. First, an appropriate amount of the projecting material 3 is accommodated in the hopper 3, and the workpiece W to be blasted is placed on a table 27 in the projection chamber 10 and the nozzle 6 is fixed at a predetermined position. . Next, if you press the operation switch of the electric circuit not shown,
Compressed air is supplied to the compressed air pipe 7 and the compressed air supply pipe 14 by a conventional electric circuit, and at the same time, the vibrating sieving machine 19 starts to vibrate, and the blower of the dust collector also starts to operate. Since the conveyor 22 also starts rotating, if the processing start switch is operated and the electromagnetic valve 4 is opened, the blast material 2 charged in the hopper 3 flows down to the nozzle 6 and is accelerated by the compressed air. It is sprayed toward the workpiece W, and processing of the workpiece W is started. In this case, since the projection material ejected from the nozzle 6 collides violently by the ejection and generates static electricity, it is preferable to spray and attach the antistatic agent to the projection material from the antistatic agent spraying means 8 to reduce the friction between the projection materials. In addition, the generation of static electricity is reduced so that the projection material 2 does not adhere to the workpiece W. Water may be used as the antistatic agent, but it is more effective if a small amount of a surfactant is added, and spraying into the projection chamber 10 is more effective.
It is more effective to provide it in the compressed air supply path in the vicinity of. When the workpiece W is a metal product and the workpiece is grounded, the projecting material attached to the workpiece can be quickly neutralized and removed. The spraying means 8 may be omitted.

Next, the projectile 2 scattered by colliding with the workpiece W or the like, dust generated as a result of processing, etc., enter the projection chamber 10 through the intake port 11 and are carried by the dust collection airflow reaching the dust collector. It is squeezed in a funnel shape below the projection chamber 10, accelerated and guided to the cyclone 16 via the exhaust pipe front part 12 and the exhaust pipe rear part 15, where the exhaust pipe front part 12 and the exhaust pipe rear part 15 Since the projecting material 2 is transported at high speed over this distance, static electricity is likely to be generated in the projecting material 2, so that the charged projecting material 2 is discharged from the exhaust pipe front 12 or the exhaust pipe. There is a possibility that a problem that the collection of the blasting material is obstructed due to the clogging in the rear portion 15 may occur. In such a case, the antistatic agent is sprayed appropriately by the antistatic agent spraying means 13 to prevent such a problem. What is necessary is just to reduce the occurrence of problems.

The blast material 2 transferred to the cyclone 16 in this way is separated from the airflow reaching the dust collector together with the dust, and flows down from the blast material collection unit 18 to the vibrating sieving machine 19 where it is larger than the blast material 2. Since the foreign matter and small foreign matter are removed by sieving, the foreign matter is temporarily stored in the dust box 20 and appropriately discarded. On the other hand, the shot material 2 from which the foreign matter has been removed is temporarily stored at one end below the screw conveyor 22. It flows down to the layer 21 and rides on the spiral blades 23 which are being rotated sequentially,
Rolled by the relative movement of the tubular outer wall 28 and the spiral blade 23,
The tubular outer wall 28, which is a metal part that is uniformly grounded
While being in contact with the spiral blades 23 and being discharged, the blast material is returned to the hopper 3 through the blast material discharge pipe 26.

As described above, the hopper 3 in the blast material collecting path
The screw conveyor 22 is provided upright as a low-speed transport path for transporting the blast material to the hopper 3 at a low speed while decelerating and rolling the flow. The tubular outer wall 28 and the spiral blade 23, which are the metal parts of the conveyor 22 that are grounded, act as static elimination means to eliminate static electricity. That is, in the conventional air blast device, the cyclone is integrally arranged at the upper part of the hopper, and the projectile moves at a high speed until it is collected in the hopper, so that the projectile is always strongly charged in the projectile flow path. Even if spraying an antistatic agent suppresses the generation of static electricity,
Although it was not possible to prevent the occurrence of the adverse effects of static electricity such as a shelf hanging phenomenon in the hopper, in the present invention, the flow of the blast material transferred to the hopper 3 in the blast material collection path immediately before the hopper was rolled. A low-speed transfer path for transferring at a low speed is provided, and the charge is sufficiently removed by a charge removing means made of a metal material provided in a grounded state on the low-speed transfer path. It is in a state of very good fluidity, and it is possible to reduce the problem that the adverse effect of static electricity such as the shelf hanging phenomenon in the hopper 3 hinders the continuation of operation.

[0014]

As described above, the air blast device of the present invention can recover and reuse the charged blasting material even after using the blasting material which is easily charged, such as resin, after precisely discharging the charged blasting material. In the recovery channel, the adverse effects of static electricity, which hinders the normal operation of the air blasting device due to the hanging of the shelf, can be suppressed to a very small level. It is possible to use an inexpensive general-purpose device such as a screw conveyor having both the function and the charge removing function, to provide the apparatus at low cost, and to increase the degree of freedom in designing the cyclone arrangement and the like. Furthermore, if a compressed air flow path part for accelerating the blast material and ejecting it from the nozzle, or a spray means for the antistatic liquid is provided at the entrance side of the dust separation means provided in the middle of the blast material recovery path, It will exhibit excellent effects. Therefore, the present invention is very large in that it contributes to the development of the industry as a solution to the problems of this type of conventional air blast device.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing a preferred embodiment of the present invention.

[Explanation of symbols]

 3 Hopper 6 Nozzle 7 Compressed air piping 8 Antistatic agent spraying means 10 Projection chamber 12 Front of exhaust pipe 13 Spraying means 14 Compressed air supply pipe 15 Rear of exhaust pipe 16 Cyclone 21 Temporary storage tank 22 Screw conveyor 23 Spiral blade 26 Projectile material discharge Tube 28 tubular outer wall

Claims (4)

[Claims] 1. An air blast apparatus in which a blast material on which an object to be processed is blasted is collected by a hopper through a blast material collecting path and is recycled for use. A low-speed transfer path that transfers at low speed while rolling the flow of blast material transferred to
An air blasting apparatus characterized in that a static eliminator made of a grounded metal material is provided in the low-speed transfer path to contact and discharge a projectile material. 2. A grounded metal member is provided in a low-speed transfer path of a blast material recovery path, and is formed of metal which connects a temporary storage tank for collected blast material provided immediately before the low-speed transfer path and a hopper. The air blast device according to claim 1, which is a screw conveyor. 3. The air blasting device according to claim 1, wherein a spraying means of an antistatic liquid is provided in a compressed air flow path portion for accelerating and projecting the blast material from a nozzle. 4. A dust separating means for separating dust and a blast material which is transported by a dust collection air flow is provided in the middle of the blast material collecting path, and a spray means for an antistatic liquid is provided at an inlet side of the dust separating means. 4. The air blast device according to claim 1, wherein the air blast device is provided.