JPH0679630A - Blasting device - Google Patents

Abstract

PURPOSE: To provide a blast device composed to circulate and use polishing material without providing a cyclone separator or a separating chamber above a blast chamber. CONSTITUTION: An air supply pipe 6 and a polishing material supply pipe 15 are connected to a blast nozzle 5 disposed in a blast chamber 1, and the polishing material supply pipe 15 communicates with a polishing material suction port 21 disposed at a lower part of the blast chamber 1. An air feed pipe 26 to feed air is disposed on the polishing material suction pipe 21 in such a way that an interval between the polishing material suction port 21 and the air feed pipe 26 is adjustable. Polishing material accumulated at the lower part of the blast chamber 1 is fed with air fed from the air feed pipe 26 into the suction port 21 to be supplied through the polishing material supply pipe 15 to a blast nozzle 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blasting device for blowing a high speed air mixed with a polishing / cleaning material to a work introduced into a blast chamber, and in particular, using the polishing / cleaning material in a circulating manner. Regarding what is configured to.

[0002]

2. Description of the Related Art The construction of a so-called suction type blasting device is called a suction type blasting device, in which an air supply pipe and a polishing / cleaning material supply pipe are connected to a blast nozzle arranged in a blast chamber, When the high-speed air sent from the air supply pipe passes through the nozzle inner hole, the polishing and cleaning material supplied from the polishing and cleaning material supply pipe is sucked by the negative pressure of the high-speed air flowing through the nozzle inner hole, and then sucked The abrasive material is mixed with high-speed air and jetted from the tip of the nozzle. The abrasive cleaning material, which mixes with the high-speed air jetted from the nozzle and flies, collides with the work and performs the blast treatment. After the blast treatment, the abrasive cleaning material falls to the lower part of the blast chamber together with dust such as burrs scraped from the work. Conventionally, the polishing / cleaning material dropped to the lower part of the blast chamber is usually circulated as follows.

That is, a cyclone separator connected to a negative pressure source is installed in the upper part of the blast chamber, and the dust-containing abrasive cleaning material that has fallen to the lower part of the blast chamber as described above is sucked up into the cyclone separator through a recovery pipe. , Then, after removing the dust from the polishing and cleaning material, drop the polishing and cleaning material into the polishing and cleaning material reservoir at the bottom of the cyclone separator, and pass the polishing and cleaning material in this polishing and cleaning material reservoir through the above polishing and cleaning material supply pipe. It should be introduced into the blast nozzle.

A dust collector is suitable as a negative pressure source to be connected to the cyclone separator, and the negative pressure generated by the suction blower of the dust collector causes the dust separated from the abrasive material by the cyclone separator to be collected. It is introduced into the dust collector through a pipe or the like.

Further, Japanese Patent Laid-Open No. 4-63680 discloses that
Using a special separation chamber installed in the upper part of the blast chamber, the dust-mixed abrasive cleaning material sucked up from the lower part of the blast chamber is separated into dust and abrasive cleaning material, and thus separated It is shown that the polishing and cleaning material accumulated in the above is supplied to the blast nozzle through the polishing and cleaning material supply pipe. Also in this case, suction of the dusting and cleaning material into the separation chamber is performed by the negative pressure generated by the suction blower attached to the dust collector or the like connected to the separation chamber.

As described above, conventionally, the abrasive cleaning material that has fallen to the lower part of the blast chamber is stored in the cyclone separator installed in the upper part of the blast chamber or the bottom of the separation chamber, and then supplied through the abrasive cleaning agent supply pipe. Supplied to the blast nozzle.

The reason why the cyclone separator or the separation chamber is installed above the blast chamber is that the abrasive material to be supplied to the blast nozzle must be positioned above the blast nozzle. That is, even though the negative pressure is generated in the blast nozzle by the air passing through the inner hole at high speed, a sufficient amount of the polishing / cleaning material must be dropped to the vicinity of the nozzle by gravity. Is not mixed with the high-speed air passing through the nozzle.

The problems of the conventional suction type blasting device having the above-mentioned structure are obvious. That is, since a cyclone separator or a separation chamber must be further installed on the blast chamber that secures a certain capacity, the device becomes large especially in the height direction, and therefore the blast device cannot be installed in some places. Sometimes.

The present invention has been devised under the circumstances described above, and is of a suction type in which a blast cleaning material is sucked and mixed with a high-speed air stream flowing through the nozzle inner hole in the blast nozzle to inject it. An object of the blast apparatus is to make it possible to significantly reduce the size of the apparatus, particularly the size in the vertical direction, while ensuring the capacity of the blast chamber.

[0010]

In order to solve the above problems, the present invention takes the following technical means. That is, the blast device according to claim 1 of the present application is a blast device for blowing high-speed air mixed with a polishing and cleaning material to a work introduced into the blast chamber to perform the blast treatment. In addition, the air supply pipe and the polishing / cleaning material supply pipe are connected to each other, and the polishing / cleaning material sucked from the above-mentioned polishing / cleaning material supply pipe by the suction force generated by the high-speed air supplied from the air supply pipe A blast nozzle configured to be mixed with air and jetted, and a polishing / cleaning material suction port which is opened at a lower portion of the blast chamber and is connected to the polishing / cleaning material supply pipe, and a tip of the polishing / cleaning material suction port. A polishing / cleaning material collecting means is provided which has an air supply pipe arranged to face each other and which sends air into the polishing / cleaning material suction port, and an adjusting means for adjusting a clearance between the suction port and the air supply pipe. It is characterized in that.

The blasting device according to claim 2 of the present application is the blasting device according to claim 1, wherein the abrasive cleaning material suction port and the air supply pipe are arranged on the same axis. It is characterized in that the diameter is smaller than the diameter of the abrasive cleaning material suction port.

Further, the blasting device according to claim 3 of the present application is the blasting device according to claim 2 in which the abrasive cleaning material suction port and / or the air supply pipe are movable in the axial direction thereof. It is characterized in that the adjusting means is configured.

Further, the blasting device according to a fourth aspect is the blasting device according to the first aspect, further comprising a dust collecting device connected to an upper portion of the blast chamber via a dust collecting pipe. To be

[0014]

When the blast device of the present invention is in operation, air generated by a low pressure air source such as a roots blower is flowing at high speed in the blast nozzle via the air supply pipe. On the other hand, in the polishing / cleaning material recovery means, an air supply pipe feeds the air generated by a blower or the like toward the polishing / cleaning material supply port. Further, preferably, a dust collecting device connected to the upper part of the blast chamber via a dust collecting pipe is operating, and a suction force generated by the dust collecting device is applied to the upper part of the blast chamber.

The polishing and cleaning material that has fallen and accumulated in the lower portion of the blast chamber is sent into the suction port together with the air flow sent from the air supply pipe. The polishing / cleaning material thus fed into the suction port passes through the polishing / cleaning material supply pipe by the synergistic work of the dynamic pressure of the air flow itself from the air supply pipe and the suction force generated by the high-speed air flowing in the blast nozzle. Sent to the blast nozzle.

That is, the blast nozzle is higher than the polishing / cleaning material collecting means arranged in the lower part of the blast chamber, especially the suction port constituting the blasting / cleaning material collecting means, but the polishing / cleaning material accumulated in the lower part of the blast chamber is as described above. As described above, the air flow sent from the air supply pipe into the suction port and the suction force generated by the high speed air flow in the blast nozzle are sent upward in the abrasive cleaning material supply pipe and mixed with the high speed air flow in the blast nozzle. It will be.

Therefore, according to the blasting device of the present invention, basically, unlike the conventional suction type blasting device of this type, it is not necessary to provide a cyclone separator or a separation chamber in the upper part of the blasting chamber, and the lower part of the blasting chamber is basically provided. It is possible to circulate and supply the abrasive cleaning material accumulated in the blast nozzle. As a result, the blasting device of the present invention is remarkably downsized in comparison with the conventional one, especially in the vertical height.

Further, as characterized in claim 2, the polishing / cleaning material supply port and the air supply pipe constituting the polishing / cleaning material recovery means are arranged on the same axis, and the diameter of the air supply pipe is supplied to the polishing / cleaning material supply. If the diameter is smaller than the diameter of the mouth, the polishing and cleaning material is conveniently formed between the suction port and the air supply pipe, and an annular clearance toward the suction port is formed from this annular clearance. Is put on the air sent from the air pipe,
It is conveniently fed into the suction port.

According to a third aspect of the present invention, the polishing / cleaning material suction port and / or the air supply pipe is moved in the axial direction to form an annular clearance formed between the suction port and the air supply pipe. By adjusting the size or axial length, an appropriate amount of abrasive material can be conveniently sent to the blast nozzle via the abrasive material supply pipe according to the particle diameter or specific gravity of the abrasive material. It can be done easily.

Further, as characterized in claim 4,
If a dust collector is connected to the upper part of the blast chamber via a dust collection pipe, the dust floating in the blast chamber will be conveniently collected by the dust collector to prevent the cleaning and cleaning material from becoming contaminated. It is possible.

In this case, by disposing a plurality of blast nozzles in the blast chamber, the high-speed air jetted from the plurality of blast nozzles maintains the air in the blast chamber in an appropriate flow state. As a result, when a negative pressure acts on the upper part of the blast chamber through the dust collecting pipe, the dust that is floating because the air in the blast is in a flowing state is conveniently collected by the dust collecting device. is there.

As described above, according to the present invention, the blasting capacity and the life of the blasting material are maintained at the same level as those of the conventional blasting apparatus, and the apparatus is remarkably downsized particularly in the vertical height. Will be.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will be described below.
A specific description will be given with reference to the drawings. The embodiment shown in the drawing is configured to deburr a lead frame that has undergone the resin molding process in the process of manufacturing an electronic component. As shown in FIGS. 1 and 2, an inlet container 2 and an outlet container 3 are formed in communication with each other on both left and right sides of the blast chamber 1, and these inlet container 2, blast chamber 1, and outlet container 3 are formed. A transport path 4 for the lead frame F is formed so as to run longitudinally through. The transport mechanism for the lead frame F will be described later.

In the blast chamber 1, a plurality of blast nozzles 5 ... Are arranged in the upper and lower sides so as to face the lead frame F conveyed on the conveying path 4. An air supply pipe 6 to which air sent from a low pressure air generation source (not shown) such as a roots blower is supplied is arranged above the blast chamber 1, and an air supply pipe branched from this air supply pipe 6 is provided. The hoses 6a are connected to the base ends of the blast nozzles 5, respectively.

An umbrella-shaped dust collecting hood 7 is arranged above the blast chamber 1, and the upper portion of the dust collecting hood 7 is exposed outside the blast chamber 1 via a dust collecting pipe 8. Is connected to the dust collector 9 disposed adjacent to (see FIG. 2). This dust collecting device 9 generates suction force by a suction blower 11 installed in the upper part of the dust collecting chamber 10, and the dust-containing air introduced from the dust collecting pipe 8 into the dust collecting chamber 10 by this suction force. A publicly known one configured to remove dust by a filter can be used.

On the other hand, the lower portion of the blast chamber 1 is reduced in diameter in a hopper shape, and below the hopper portion 12, polishing / cleaning material recovery means 13 is constructed.

In this embodiment, as well shown in FIGS. 3 and 4, a recovery container 14 is connected to the lower end of the hopper portion 12, and a lower part of the recovery container 14 is
A means for circulating the polishing / cleaning material that has fallen and collected in the recovery container 14 through the polishing / cleaning material supply pipes 15 to the respective blast nozzles 5 is constructed. Further, a pull-out type sieve 16 is provided on the upper portion of the recovery container 14 so that coarse burrs generated by the blast treatment can be removed. In addition, at the lower end of the collection container 14,
A drawer 18 provided with a sieve 17 having a mesh finer than that of the abrasive material used is provided so that fine dust having a large specific gravity can be sieved and removed. Also,
Pipes 19 and 20 for introducing the polishing / cleaning material that has dropped to the bottoms of the inlet container 2 and the outlet container 3 into the recovery container 14 are connected to the side portions of the recovery container 14.

Now, in the present invention, the recovery container 1 is used.
The polishing / cleaning material collecting means 13 for circulating the polishing / cleaning material accumulated in 4 to the above-mentioned blast nozzles 5 ... Arranged in the vertical direction of the blast chamber is connected to the base end of each blast nozzle 5. And a polishing / cleaning material suction port 21, which communicates with the polishing / cleaning material supply pipe 15, and a distal end of the polishing / cleaning material suction port 21, which is opposed to the polishing / cleaning material suction port 21, and which feeds air into the polishing / cleaning material suction port 26. ..., the suction port 21 ..., and the air supply pipe 26
It is constituted by adjusting means 23 for adjusting the clearance between the ...

In the present embodiment, as shown in FIG. 4, the abrasive cleaning material suction port 21 ... Pipe 21a horizontally supported by the side wall 14a of the recovery container 14
It is composed by. The number of pipes 21a ... Corresponds to the number of blast nozzles 5 ... Arranged in the blast chamber. The outer ends of the pipes 21a ... And the base ends of the nozzles 5 ... Are connected to each other by a polishing / cleaning material supply hose 15a. Further, the pipes 21a ... Can be slid in the horizontal direction with respect to a boss portion 24 formed through one side wall of the collection container 14, and the adjusted position is the boss portion 2 described above.
4 is retained by a set screw 25 screwed from the side wall.

On the other hand, the other side wall 1 below the recovery container 14
Each of the pipes 21 forming the suction ports 21 ...
The air supply pipes 26 ... Are supported in a penetrating manner so as to have the same axis as a. The pipes 26a forming these air supply pipes 26 are also inserted and supported in the boss portion 27 supported on the other side wall of the recovery container 14 so as to be horizontally movable. Then, a set screw 28 screwed into the boss portion 27 is provided.
Thus, the positions of the air supply pipes 26 ... Are adjusted after being adjusted in the axial direction.

In the present embodiment, as clearly shown in FIG. 4, the diameter of each of the air supply pipes 26 ...
It is smaller than the inner diameter of the pipes that make up. Further, the inner diameters of the inner end portions of the pipes 21a forming the suction ports 21 are designed so that the inner diameters thereof taper toward the inner side.

Therefore, by adjusting the axial position of one or both of the pipes 21a and the air supply pipes 26 which form the suction ports 21 ..., the tips of the suction ports 21 ... and the air supply pipes 26 ... Annular clearance between the parts 2
The size and axial length of 9 can be adjusted appropriately.

The outer ends of the air supply pipes 26 ...
It is connected to the surge tank 31 (FIG. 2) via the ... And air is sent to the surge tank 31 by a blower 32. Therefore, the air generated by the blower 32 is sent to each of the air supply pipes 26 ... Through the surge tank 31 or the hose 30.

In the operating state of the blasting device, the dust collecting device 9 is in the operating state, suction force is applied to the dust collecting hood 7 above the blast chamber 1, and air from a blower (not shown) is applied. Are sent to the nozzles 5 through the air supply pipes 6 and 6a, and the air from the blower 32 is sent to the air supply pipes 26 in the polishing / cleaning material recovery means 13. Of course, the transport mechanism for transporting the work (in the present embodiment, the lead frame F) is also operating, but this transport mechanism is not an essential part of the present invention and will be described later.

In the blasting device, a certain amount of the cleaning material S
Are used cyclically. That is, the abrasive cleaning material which has been sprayed by high-speed air from each blast nozzle 5 and finished the blasting process falls below the blast chamber 1 due to gravity and collects in the abrasive cleaning material recovery container 14 (FIG. 4). ). At this time,
In the present embodiment, of the dust scraped off from the work by the blasting process, relatively large dust such as coarse burr is removed by the coarse burr screen 16.

Of the dust scraped off from the work by the blasting process, the dust having a small specific gravity and fine dust rides on the air in the blast chamber which is in a flowing state because a plurality of blast nozzles 5 are provided. However, the fine floating dust with such a small specific gravity
It is sent to the dust collector 9 through the hood 7 or the dust collecting pipe 8.

In the polishing / cleaning material recovery means 13 arranged at the lower part of the recovery container 14, when air is sent to each of the polishing / cleaning material suction ports 21 via the air supply pipes 26 (FIG. 4), this air flow The polishing and cleaning material S accumulated in the lower portion of the recovery container 14 is drawn into the suction ports 21 ...
The polishing and cleaning material drawn into the suction ports 21 in this manner is given a dynamic pressure due to the air flow from the air supply pipes 26, and a negative pressure generated by the high-speed air flowing in each blast nozzle 5 ... By the action, it is expediently sent to each blast nozzle 5 through the abrasive cleaning material supply hose 15a as the abrasive cleaning material supply pipe 15, and then mixed with the high-speed air flow in the blast nozzle and injected again. It In other words, the abrasive cleaning material drawn into the suction ports 21 ... blasts at a high position due to the interaction between the pumping force generated by the air flow from the air supply pipes 26 ... And the negative pressure generated in the blast nozzle. It can be conveyed to the nozzle 5 through the abrasive cleaning material supply hose 15.

Moreover, the suction ports 21 ... And the air supply pipe 2
By adjusting the size and the axial length of the annular clearance 29 formed by 6 ..., the amount of the polishing / cleaning material fed into the suction port 21 ... according to the particle size or the specific gravity of the polishing / cleaning material to be used. Can be adjusted appropriately, and it is extremely easy to properly adjust the amount of the polishing and cleaning material sprayed from the blast nozzle 5.

By the way, as described above, the above-described embodiment is particularly formed in order to efficiently remove burrs that cling to the manufacturing frame F after the resin molding process so as to cling to the manufacturing frame F. It was done. The manufacturing frame F generally has a rectangular strip shape in which a thin metal plate is punched as shown in FIG. 8, and in the present embodiment, the manufacturing frame F is formed.
Is conveniently transported horizontally in the blasting chamber, and can be deburred by blasting with a plurality of blast nozzles 5.

First, as shown in FIG. 7, the transport path 4 which runs the inlet container 2, the blast chamber 1 or the outlet container 3 in the horizontal direction is provided on the opposing surfaces of the pair of left and right plate-shaped rails 33, 33. Lateral V formed to correspond to the width of the frame F
The V-shaped grooves 34, 34 are formed, and the frame F can be slid and conveyed by engaging the bottoms of the V-shaped grooves 34, 34 with the both side edges of the frame F.

An endless chain 36 wound around a plurality of sprockets 35 is disposed below the transport path 4. The endless chain 36 is formed with a portion that horizontally runs below the transport path 4 along the endless chain 36.
Each frame F introduced into the transport path 4 is slid and transported in the exit direction by being pushed by the feed claws 37 provided at equal intervals on the endless chain 36.

At the entrance of the transport path 4, a feeding device 38 is provided for feeding the frame F to the transport path 4 one after another in synchronization with the position of the feed claw 37 of the endless chain 36.

This feeding device 38 is shown in FIGS.
As shown in FIG. 3, a feeding guide 39 extending horizontally at the same height as the conveying path 4, and the feeding guide 39
Above the pair of drive pulleys 40 and 40, a pair of front and rear drive pulleys 40, 40 are wound around the rubber belt 41, and a notch 42 provided in the feeding guide 39 is provided.
Backup roller 4 that can rotate by contacting with a rubber belt wound around it so as to face 0, 40
3 and 43. Delivery guide 3
When the frame F is inserted into the entrance of 9 by manual operation or an automatic alignment mechanism so that the leading end of the frame F is slightly sandwiched between the rubber belt 41 and the backup roller 43, the rubber belt 41 becomes endless chain 36. The frame F is rotationally driven so as to be fed into the transport path 4 in synchronism with the position of the feed claw 37. The frame F once engaged and held in the transport path 4 is
The feeding pawls 37 of the endless chain 36 continuously convey the conveying path 4 forward.

As described above, the transport path 4 engages and holds both side edges of the frame F that is fed horizontally.
The upper and lower surfaces of the central portion in the width direction where the resin mold portion is formed can be exposed. Therefore, deburring of the upper and lower surfaces of the resin mold portion is performed by a plurality of blast nozzles 5 arranged above and below. Can be done conveniently.

The frame F that has reached the front end of the transport path 4 after undergoing the deburring process is transported to the next step via the chute 44 or is recovered in a recovery box (not shown).

As described above, in the blasting apparatus of the present invention, unlike the conventional case, the polishing and cleaning material accumulated in the lower portion of the blast chamber is not temporarily stored in the cyclone separator or the separation chamber arranged in the upper portion of the blast chamber. Instead, the polishing / cleaning material accumulated in the lower portion of the blast chamber 1 is directly supplied to the polishing / cleaning material supply pipe by the interaction of the air feeding action of the air supply pipe 26 and the suction action of the negative pressure generated in the blast nozzle 5. The polishing and cleaning material is circulated by being sent to the blast nozzle 5 through 15 ... Therefore, unlike the conventional case, it is not necessary to further install a cyclone separator or a separation chamber on the blast chamber, and it is possible to remarkably reduce the vertical height of the device. It dramatically increases.

Further, it is possible to easily set the amount of the polishing / cleaning material to be jetted from the blast nozzle appropriately according to the particle size or the specific gravity of the polishing / cleaning material, and to properly set the blast treatment efficiency according to the work. be able to.

Of course, the present invention is not limited to the above embodiment. The purpose of blasting or the object to be blasted is not limited in any way. As a means for adjusting the clearance between the suction port and the air supply pipe, in the embodiment, both the pipe forming the suction port and the pipe forming the air supply pipe are configured to be movable in the axial direction. One of them may be adjustable in movement, and also as a means for moving in the axial direction, in addition to simple slide fitting, a screw is formed on the outer circumference of each pipe itself and a boss portion holding these pipes is formed. A female screw may be formed so that the axial position can be adjusted by a screw feeding action by rotating each pipe. In this case, the set screw after adjusting the axial movement may be unnecessary.

Further, regarding the above-mentioned embodiment, the dust collecting force can be easily adjusted by providing a damper whose opening can be adjusted in the dust collecting pipe connecting the hood to the dust collecting device. When using a polishing / cleaning material having a small specific gravity, it is possible to reduce the flow rate in the pipe with a damper so that the polishing / cleaning material is not sent to the dust collector, which is advantageous.

Further, in the above-mentioned embodiment, the collecting means is provided with a pull-out type sieve for removing coarse burrs from the blasting material after blasting. For example, a vibrating type sieving apparatus is attached to remove the coarse burrs. It is possible to further increase efficiency. Further, regarding the specific shape or structure of each part constituting the invention of the present application, all design changes are within the scope of the invention of the present application, as long as the features in the functional aspect defined in the claims are exhibited. included.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view schematically showing the overall configuration of an embodiment of a blasting device of the present invention.

FIG. 2 is a schematic cross-sectional view taken along the line II-II of FIG.

3 is an enlarged cross-sectional view taken along the line III-III in FIG.

FIG. 4 is an enlarged sectional view taken along line IV-IV in FIG.

FIG. 5 is a sectional view showing details of a feeding device.

6 is a sectional view taken along line VI-VI of FIG.

7 is a cross-sectional view of the conveyance path and is a view corresponding to an enlarged cross-sectional view taken along the line VII-VII of FIG.

FIG. 8 is a plan view showing an example of a semiconductor manufacturing frame which is an example of a work.

[Explanation of symbols]

 1 Blast Chamber 5 Blast Nozzle 6 Air Supply Pipe 13 Abrasive Cleaning Agent Recovery Means 15 Abrasive Cleaning Agent Supply Pipe 21 Abrasive Cleaning Agent Suction Port 23 Adjusting Means 26 Air Pipe

Claims (4)

[Claims] 1. A blasting device for blasting a workpiece introduced into a blasting chamber by blowing high-speed air containing a polishing and cleaning material, the blasting device being disposed in the blasting chamber and having an air supply pipe. And the abrasive cleaning material supply pipe are connected, so that the abrasive cleaning material sucked from the above abrasive cleaning material supply pipe is mixed with the above high speed air by the suction force generated by the high speed air supplied from the air supply tube to be jetted. A configured blast nozzle, and a polishing / cleaning material suction port that opens at a lower portion of the blast chamber and is connected to the polishing / cleaning material supply pipe, and a tip is disposed to face the polishing / cleaning material suction port and the polishing / cleaning material is also provided. A blasting device comprising: an air supply pipe for sending air into the suction port; and a polishing and cleaning material recovery means having an adjusting means for adjusting a clearance between the suction port and the air supply pipe. 2. The polishing / cleaning material suction port and the air supply pipe in the polishing / cleaning material recovery means are arranged on the same axis, and the diameter of the air supply pipe is smaller than that of the polishing / cleaning material suction port. The blasting device of claim 1, wherein: 3. The blasting device according to claim 2, wherein the adjusting means is formed by making the abrasive cleaning material suction port and / or the air supply pipe movable in the axial direction. 4. The blast apparatus according to claim 1, further comprising a dust collecting device connected to the upper portion of the blast chamber via a dust collecting pipe.