JPS6322272A - Sandblast apparatus and blast head thereof - Google Patents

Abstract

PURPOSE:To keep off any pollution caused by swarf of dust to the full, by inserting a sandblast nozzle and a suction nozzle into a recovery chamber of a sandblast hood, and installing an elastic or flexible seal member in a peripheral edge of the blast hood coming into contact with a work surface in addition. CONSTITUTION:Polishing-cleaning materials are sprayed to a work surface by the sandblast nozzle 102 inserted into the inside of a sandblast hood 101, an a mixture of swarf and these materials to be produced is removed by a suction nozzle 103. The inside of the blast hood 101 is hermetically sealed by the elastic or flexible seal member installed in the peripheral edge of the blast food 101 to be contacted with the work surface, so that the swarf and polishing- cleaning materials are designed so as not to flow out. In consequence, even if there are irregularities on the work surface, dust and polishing-cleaning materials are all fully absorbable, thus pollution is fully preventable without entailing any efflux to the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a sandblasting device, and more particularly to a blasting device that can prevent contamination due to dust generated during sand blasting, and a blast head used in the device.

(Prior Art) Sandblasting equipment is useful for removing rust from weathered surfaces of concrete structures such as buildings and metal structures. However, such sandblasting equipment generates dust and concrete contaminants during operation, and therefore, in many cases, relatively large-scale construction such as covering the structure with large sheets or tents is required to prevent dust and other contaminants from becoming a source of contamination. A lot of work is required.

A sandblasting device proposed to avoid such inconveniences is described in Japanese Utility Model Application Laid-Open No. 59-193657. This device is equipped with an injection nozzle in the recovery hood, and this injection nozzle is connected to a supply hose that supplies working particles or abrasive material together with compressed air, and the abrasive material is delivered to the surface to be polished. It is designed to be injected into the air. A recovery hose is connected to the recovery hood to recover the sprayed abrasive material. In this device, the abrasive material sprayed from the spray nozzle is collected by a collection hood and further collected via a collection hose.

(Problems to be Solved by the Invention) However, although the conventional sandblasting devices described above are effective in preventing the abrasive debris or dust generated during blasting from being emitted to the outside, It's not something that can be prevented.

(Means for Solving the Problems) Therefore, an object of the present invention is to provide a sandblasting device that can sufficiently prevent contamination caused by abrasive debris or dust generated during blasting. In addition, the present invention has a blast head that can effectively absorb generated dust so that it does not flow outside, has an excellent noise reduction effect, and can sufficiently absorb dust and abrasive material even if the surface to be polished is uneven. The purpose is to provide equipment. To achieve this objective, the sandblasting device of the present invention uses a sandblasting head device having a generally ball-shaped sandblasting hood defining a collection chamber. A sandblasting nozzle directed toward the surface to be polished is inserted into the collection chamber of the sandblasting hood. The sandblasting nozzle is connected to an abrasive supply source and sprays the abrasive along with compressed air onto the surface to be polished.

Further, a suction nozzle connected to an air intake device is inserted into the collection chamber of the sandblasting hood in order to suck up and remove abrasive debris generated during the blasting operation along with the abrasive material. Furthermore, an elastic or flexible sealing member is provided on the peripheral edge of the blast hood that contacts the surface to be polished, to prevent contaminants from flowing out.

(Function) According to the sandblasting device of the present invention, the sandblasting nozzle inserted into the sandblasting hood sprays the abrasive onto the surface to be polished, and the mixture of generated abrasive debris and abrasive is collected by the suction nozzle. removed. The inside of the blast hood is sealed by an elastic or flexible sealing member provided at the peripheral edge of the blast hood that comes into contact with the surface to be polished, and the cleaning debris and abrasive materials are prevented from flowing outside. .

(Example) Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

As shown in FIG. 1, the plast apparatus of the present invention has an abrasive supply device l. The abrasive supply device 1 includes an abrasive recovery tank 2 and a blast tank IO, which will be described later. Abrasive material recovery tank 2 communicates with blast tank 10 via shutoff valve 11 .

A blast head device 100 including a blast hood 101, a sandblast nozzle 102, and a suction nozzle 103 is connected to the abrasive supply device 1. in fact,
The blast tank IO is connected to the blast nozzle 102 of the sandblasting head device 100 via a supply pipe 32, and is configured to blast abrasive material. The suction nozzle 102 of the blast head device 100 is connected to the collection pipe 34
It is connected to a filtration device 4 having a cyclone filter 40 via. The cyclone filter 40 is connected to the outflow valve 4
4, it communicates with an abrasive material collector 5 having a classifier 50. The classifier 50 classifies the collected mixture of abrasive debris and abrasive material, and collects the abrasive material. The abrasive material classified by the classifier 50 is supplied to the recovery tank IO via the abrasive material recovery hopper 52 and the supply pipe 55.

On the other hand, the cyclone filter 40 of the filtration device 4 is connected to the air intake device 8 via the air filtration device 7. In this configuration, the suction nozzle 103, the collection pipe 34 and the filtration device 4
Negative pressure is generated inside, and the mixture of abrasive material and abrasive material is sucked into the collection chamber of the blast hood +01.

Note that various types of abrasive materials such as silica sand can be used as the abrasive material. Most preferred, however, is an abrasive consisting of slag produced in a converter. For use as an abrasive, the slag is cooled and reduced to 0.7 to 2.4 mm.
Grind to a particle size of

The abrasive material manufactured in this way has a Vickers hardness of 700±
It is 100HV. This hardness is sufficient for use as an abrasive. Also, because each particle has multiple sharp edges, such abrasives are effective in sandblasting. Furthermore, the abrasive material consisting of slag is highly alkaline, ie, pH 10, and can impart corrosion protection to the treated surface.

A shutoff valve 11 provided between the recovery tank 2 and the blast tank 10 allows the recovered abrasive material to be supplied from the recovery tank to the blast tank 10. Further, the shutoff valve 11 can prevent the pressure inside the blast tank 10 from being introduced into the recovery tank 2. The shutoff valve 11 consists of a valve seat 12 and a conical valve member 18. A conical recess is formed in the bottom of the valve member 18 . The pressure tube 13 extends upwardly so that its upper end opposes the conical recess 1π of the valve member 18. The pressure pipe 13 extends through the side wall of the blast tank 10. The other end of the pressure pipe 13 is connected to a pressure accumulator 16.
6 is connected to an air compressor 17. A pressure regulating valve 13a is provided in the pressure pipe, and communicates and isolates the pressure accumulator 16 and the blast tank 10 from each other. When pressure is applied within the blast tank 10, compressed air is discharged into a conical recess in the valve member 18. The pressure discharged from the outlet of the pressure pipe 13 causes the valve member 18 to shift upward and engage the valve seat I2, and communication between the recovery tank 2 and the blast tank 10 is cut off.

On the other hand, the pressure in the blast tank 10 is maintained higher than the pressure in the recovery tank by the pressure introduced through the pressure pipe 3. As a result, the pressure differential between the recovery tank 2 and the blast tank 10 maintains the valve member 18 in the engaged position with the valve seat 12, cutting off communication between these tanks.

An exhaust port is formed in the blast tank IO, and an exhaust pipe 14a is connected to the exhaust port. Exhaust pipe +
An exhaust valve 14 is provided at the end of 4a. The pressure in the blast tank 10 is controlled by the exhaust valve 14, the pressure in the storage tank is reduced below the pressure in the recovery tank chamber 2, and the abrasive material recovered in the recovery chamber is introduced into the blast tank 10. . The pressure within the blast tank 10 is regulated by adjusting the position of the pressure control valve 13a. In order to adjust the position of the pressure regulating valve 13a, a pressure sensing sensor is provided within the blast chamber 10, as shown by the phantom line in FIG. A pressure sensitive sensor is connected to the controller. The controller outputs a pressure control signal;
Adjust the position of the pressure regulating valve 13λ. Further, in order to detect the amount of abrasive material in the blast tank, an abrasive material amount sensor such as a load cell is provided in the blast tank 10. When the amount of abrasive material in the blast tank IO decreases below a predetermined amount, the controller outputs an abrasive material supply control signal, and the signal is supplied to the exhaust valve 14.
Exhaust valve 14 opens. Further, when the pressure inside the blast tank IO exceeds a predetermined pressure, the controller may output a supply control signal to open the exhaust valve 14.

A flow control valve 15 is provided between the outlet of the blast tank IO and the supply pipe 32. The position of the flow control valve 15 is adjusted electrically or electromagnetically by a manually operated switch located adjacent to the blast nozzle 102. This type of flow control valve 15 was developed in Japanese Patent Application Publication No. 5
3-16989. In the above embodiment, a manual switch is used to control the opening and closing of the flow rate control valve, but it can also be controlled by a controller. Further, although the manual switch in the above embodiment is provided adjacent to the blast nozzle, it may be located at a position where it can be easily operated manually. Furthermore, the configuration of the flow control valve is
-16989, but is not limited to that disclosed in
Any suitable arrangement of flow control valves that can be electrically or electromagnetically controlled by a manual switch or controller may be used.

The cyclone filter 40 of the filtration device 4 has a funnel 4
2. Connected to a classifier 50 via a rotary valve 44 and an inflow pipe 57. The rotary valve 44 is driven at a constant speed by a drive motor 45. Therefore,
The rotary valve 44 allows a predetermined amount of the abrasive debris and abrasive material mixture to be introduced into the classifier. On the other hand, the rotary valve 44 prevents the negative pressure within the cyclone filter 40 from being introduced into the classifier.

Various types of classifiers can be used as the classifier 50 for classifying the abrasive material and the abrasive waste. In this embodiment, the classifier 50 is rotated by the pneumatic motor 54 to introduce dust into the hopper 51.

On the other hand, the abrasive material classified from dust by the classifier 50 is introduced into the collection hopper 52. A discharge port 53 of the recovery hopper 52 is connected to the recovery tank 2 via a supply pipe 55.

The recovery tank 2 is connected to one inlet 6I of the two-way valve device 6.
The other inlet 60 of the valve device 6 is connected to the exhaust port 43 of the cyclone filter 40 . The two-way valve device 6 is provided with a discharge port 62,
The outlet 62 is connected to the intake device 8 via the air filtration device 7 .

The two-way valve device 6 has inlets 60 and 6I and an outlet 6.
It consists of a hollow valve housing with 2. A pair of butterfly valves 63 are provided inside the valve housing. Each butterfly valve provides communication and isolation between the cyclone filter 40 and the air filtration device 7 and between the recovery tank 2 and the air filtration device 7. Throttle valve 63
are each connected to a motor 64, by which they can be driven to adjust the position of the valve. The motors 64 are interlocked with each other so that when one throttle valve opens, the other throttle valve closes.

Preferably, the motors 64 are connected to a controller and driven in synchronization with each other by valve position control signals from the controller.

The air filtration device 7 consists of a filter housing 72,
The filter housing 72 is provided with an intake lower 5 that is connected to the two-way valve device 6 . A substantially cylindrical air filter 74, such as a bag filter, is provided within the filter housing. The air passed through the intake lower 5 and introduced into the filter housing is passed through the air filter 74.
and is exhausted into the filtration chamber 73. The filtration chamber 73 is
It is connected to the exhaust lower end of the blower 80 of the intake device via the exhaust lower end and suction duct 81 .

Further, the suction duct 81 is connected to the ejector device 9 via a switching valve 83. The switching valve 83 is coupled to a motor 84 and can thereby control the air filtration device 7 to be selectively connected to the blower 80 or the ejector device 9.

The blower 80 is provided with an exhaust port connected to a silencer 82 so as to be able to exhaust air. The blower 80 generates a large amount of negative pressure and is capable of suctioning a mixture of abrasive debris and abrasive material.

The ejector device 9 consists of a number of ejectors.

Each ejector consists of a closed case 92 that communicates with an injection pipe 90 at one end and an exhaust pipe 91 at the other end. The injection pipe 90 is connected to the pressure accumulator 6 via a pressure line 96. On the outside of each exhaust pipe 91 is provided a discharge drum 94 whose inner surface is covered with sound-deadening glass wool. The compressed air from the pressure accumulator 16 is transferred to the injection pipe 90
The air is exhausted from the air into the sealed case 92. The exhausted air is
The air passes through the sealed case 92 and is exhausted through the exhaust pipe 9I. This creates negative pressure or suction within the closed case. The negative pressure generated within each sealed case is added to the negative pressure within the suction duct via the suction pipe 95.

In this embodiment, the filter device 4, classifier 5, and abrasive material supply device I are mounted on a trolley 56 and are movable. Further, the air filtration device 7, the air intake device 8, and the exhaust device 9 are also mounted on the trolley 77 and are movable.

2, 3 and 4 illustrate a preferred embodiment of the blast head +00. As illustrated, the sandblasting hood 101 is generally box-shaped with a substantially rectangular cross section and rounded corners. blast hood 10
I consists of an outer layer plate 113, an intermediate layer 112, and an inner layer 111, and the outer layer is a damping steel plate press-formed into a desired shape. As is well known, damping steel plates have a thickness of 0.4 to 3.2
It has a laminate structure consisting of a pair of steel plates with a diameter of 2 mm and an elastic resin sandwiched between the steel plates. The intermediate layer 112 is made of honeycomb board or foamed resin, and the inner layer Ill is made of wear-resistant rubber.

The inner layer Ill is formed with a protrusion extending from the peripheral edge of the outer layer plate 113 and the intermediate layer 112 toward the surface to be polished.

A cylindrical end 110 is formed in the protrusion of the inner layer 111 . The cylindrical end 110 is elastically deformable to provide a dust seal between the surface to be polished and the sandblasting hood.

A plan 104 extending toward the surface to be polished is attached to the peripheral edge of the outer plate +13. ``Brush! 04 is covered by a seal piece 141 fixed to the outer layer plate 113.

A handle 106 and a pressure regulating valve 10'7 are attached to the outer surface of the blast hood. To allow the blast head to move smoothly along the surface to be polished,
The pressure in the injection chamber 115 of the blast hood 101 can be adjusted by manually operating the pressure control valve 107 so that the suction pressure does not become excessive.

The blast nozzle 102 is inserted into the injection chamber 115 through an opening formed in the side surface of the blast hood 101 . The opening into which the blast nozzle 102 is inserted is inclined at the upper corner of the blast hood 101, and the axis of the blast nozzle +02 is inclined downward and extends toward the surface to be polished. Therefore, plast hose 3
2 Nutrients and compressed air together with the abrasive material are blasted into the blast nozzle 1.
02, the abrasive material is sprayed at an oblique angle to the surface to be painted. In this way, rust on metal surfaces and weathered surfaces on concrete structures can be removed.

The suction nozzle 103 is inserted into the injection chamber 115 from the bottom of the blast hood 101. As shown in FIG. 2, the suction nozzle 103 has an inner pipe 131 and an outer pipe 132.
The outer tube 132 is provided with a number of holes 134. An annular space is formed between the inner pipe 131 and the outer pipe 132, the annular space 133 communicates with the inner space 133 of the inner pipe 132 at a confluence part 136, and the confluence part 136 is connected to the recovery hose 130. There is.

A cover plate 13 is provided on the inner surface of the blast hood 101.
7 is attached to define a collection chamber 114 around the upper end of an outer tube 132 with holes 134 circumferentially provided therein. A slight gap 138 is provided in the cover plate 137 so that the recovery chamber 114 communicates with the injection chamber l15. With this configuration, the internal space 133 of the inner tube 132
communicates with the injection chamber 115, and the mixture of dust and abrasive material inside is discharged. On the other hand, the annular space 135 is a cover plate! Communication with the injection chamber is cut off by 37, and the hole! 3
4 to the collection chamber 114, so that the mixture of dust and abrasive material in the collection chamber +14 is transferred to the annular space 135.
pass through the inside.

A pair of seal tongue pieces 105 are provided at the free end of the seal piece 141.
is connected. The upper seal piece 10'5 extends upward from the blast hood 101, and the lower seal piece 10'5 extends upward from the blast hood 101.
5 extends downward from the blast hood 101. Fifth
As shown in the figure, each seal tongue 105 consists of a metal wire frame 151 and a rubber bag 152 into which the metal wire frame 151 is inserted. metal wire frame 1
51 is formed into a substantially U-shape, and protrusions 153 protruding in the lateral direction are provided at both ends. The protrusion 153 is rotatably fitted into a recess formed in the knoll piece. 'In this embodiment, the width of the sealing tongue 10'5 corresponds to the width of the surface to be polished. The seal tongue piece 105 is rotatable. During injection, since the pressure inside the injection chamber IIS is reduced, the upper sealing tongue 105, which acts as a trailing tongue, presses against the concave surface 181 created when the rusted or weathered surface is removed, and removes dust. It can be sealed.

Although the sandblasting device of the present invention uses the sealing tongue as described above, other sealing tongues may also be used. For example, the seal tongue may be formed by a flexible plate that is biased by a spring toward the surface to be cleaned.

When operating the sandblasting device according to the invention:
By introducing compressed air from the pressure accumulator 16, the pressure inside the blast tank IO is increased to a predetermined pressure. Thereafter, the blower 80 or the ejector 90 is driven to reduce the pressure inside the blast head device via the recovery device 4 and the recovery tank 2.

Abrasive material is supplied from the blast tank IO to the blast nozzle 102 via the supply hose 32 along with compressed air. In this way, the abrasive material is transferred to the blast nozzle 1.0
2 toward the surface to be polished. A mixture of abrasive material and abrasive debris is generated in the ejection chamber 115 of the blast head device 100, and a portion of the mixture flows into the collection chamber 114. Injection chamber 11
5 and the mixture in the collection chamber 114 are absorbed into the suction nozzle by negative and positive, and introduced into the cyclone filter 40 via the collection pipe 34. By the cyclone filter 40,
Air and a mixture of abrasive material and debris are separated. Air is supplied to the air filter 74 of the air filtration device 7 via the suction hose 65 and exhausted by the blower 80 or ejector 90.

On the other hand, the mixture in the air filter separated from the air is
It is supplied to a classifier 50 and classified into abrasive material and abrasive waste.

Abrasive debris is collected in a hopper 51, and abrasive material is collected in a hopper 52. When a predetermined amount of abrasive material is collected into the hopper 52, a negative pressure is created in the collection chamber by the two-way valve device 6. When the pressure inside the recovery tank 2 is reduced, the abrasive material in the hopper 52 is introduced into the recovery tank 2 via the recovery pipe 55.

During the above operation, the suction chamber 1 in the blast head device 100
15 is sealed to prevent dust from escaping,
It can prevent the generation of pollutants. Furthermore, even if unevenness occurs on the surface to be polished during the blasting operation, the seal tongue piece 1
05, the dust-tight state is maintained.

According to the above-described configuration, the noise generated in the injection chamber can be absorbed by the blast hood 101. Also,
By using damping steel plates to form the blast hood, the vibrations of the blast head can be reduced.

(Effects of the Invention) As described above, according to the present invention, since the suction chamber in the blast head device is sealed, abrasive debris does not flow out to the outside, which is effective in preventing contamination.

Further, even if the surface to be polished becomes uneven during the blasting operation, the sealing tongue prevents the cleaning debris and the abrasive material from flowing out. Furthermore, since the blast hood is made of sound-deadening material, it can absorb the noise generated in the injection chamber, and since the blast hood is made of damping steel plate, it can reduce the vibration of the blast head. .

[Brief explanation of drawings]

FIG. 1 is a side view of a sandblasting device showing an embodiment of the present invention, FIG. 2 is an enlarged view of a sandblasting head device used in the sandblasting device of FIG. 1, and FIG. 3 is an enlarged view of the sandblasting head device of FIG. 2. 4 is a rear view of the sandblasting head device of FIG. 2, and FIG. 5 is an enlarged perspective view of a seal piece used in the sandblasting head device of FIG. 2. l Abrasive material supply device 2 Abrasive material recovery tank 4i! !
filtration device 5 Abrasive material collection device 7 Air filtration device 8 Intake device 100 Blast head 101 Blast hood 102 Blast nozzle 103 Suction nozzle 105 Seal tongue piece Fig. 3 Fig. 5 Fig. 4 L

Claims (36)

[Claims] (1) A blast hood defining an ejection chamber having an opening facing the surface to be polished; and a blast hood interposed between the blast hood and the surface to be polished and in pressure contact with the surface to be polished; a sealing means for cutting off communication from the outside; and a sealing means inserted into the ejection chamber through a first opening formed in the blast hood and connected to an abrasive material supply source to supply the abrasive material to the target material. a blast nozzle that injects toward the surface to be polished; and a second opening formed in the blast hood at a position different from the first opening; the blast hood is inserted into the injection chamber; A blast head device for sandblasting, comprising a suction nozzle connected to the suction nozzle for introducing negative pressure into the ejection chamber to suck in the mixture of abrasive material and abrasive debris generated during the ejection operation. (2) The blast head device according to claim 1, wherein the blast hood is made of a damping steel plate. (3) The blast head device according to claim 1, wherein the blast hood is made of a noise absorbing material. (4) The blast head device according to claim 1, wherein the sealing means comprises a sealing piece that extends from the peripheral edge of the blast hood and contacts and seals the surface to be polished. (5) The blast head device according to claim 4, wherein the seal piece is made of rubber. (6) The blast head device according to claim 5, wherein the seal piece has a cylindrical portion that can be elastically deformed and abutted against the surface to be polished to seal the surface. (7) The sealing means is provided at least on the rear side of the blast hood in the direction of movement, and includes a sealing tongue that comes into close contact with the surface to be polished to ensure a sealed state between the blast hood and the surface to be polished. A blast head device according to claim 1, characterized in that: (8) The sealing means is provided at least on the rear side of the blast hood in the traveling direction, and closely contacts the surface to be polished and works in conjunction with the seal piece to seal between the blast hood and the surface to be polished. Blast head device according to claim 1, characterized in that it consists of a sealing tongue that guarantees the condition. (9) The suction nozzle consists of an inner and an outer tube, defining a first suction passage and a second annular suction passage between the inner tube and the outer tube. The blast head device according to scope 1. (10) A partition wall separating the injection chamber and the recovery chamber is provided in the blast hood, and means for communicating between the injection chamber and the recovery chamber is provided in the partition wall, and the first absorption passage communicates with the injection chamber. The blast head device according to claim 9, wherein the second absorption passage communicates with the recovery chamber. (11) The blast head device according to claim 2, characterized in that the blast hood is provided with a layer of sound-deadening material. (12) The blasting apparatus according to claim 11, wherein the sealing means is comprised of a sealing piece that extends from the peripheral edge of the blast hood and tightly contacts and seals the surface to be polished. head device. (13) The blast head device according to claim 12, wherein the seal piece is made of rubber. (14) The blast head device according to claim 13, wherein the seal piece has a cylindrical portion that can be elastically deformed and come into close contact with the surface to be polished. (15) The sealing means is provided at least on the trailing side of the blast hood, tightly contacts the surface to be polished, and works in conjunction with the sealing piece to maintain a sealed state between the blast hood and the surface to be polished. 15. Blast head device according to claim 14, characterized in that it consists of a sealing tongue ensuring that. (16) The blast head device according to claim 1, wherein the abrasive material is slag produced in a converter. (17) Claim 16, wherein the abrasive material has a Vickers hardness of 700±100HV.
Blast head device as described in section. (18) The blast head device according to claim 16, wherein the abrasive material is alkaline. (19) Consisting of an abrasive material supply source that supplies abrasive material at a predetermined pressure, an air intake device, a blast head device, and an abrasive material recovery device, the blast head device defines an ejection chamber and a blast hood with an opening on the side to be polished; a sealing means for sealing between the blast hood and the surface to be polished to cut off communication between the ejection chamber and the outside; and a first through hole formed in the blast hood. a blast nozzle inserted into the injection chamber through the blast nozzle and connected to the abrasive material supply source to be supplied with abrasive material; and a blast nozzle formed at a position different from the first through hole of the blast hood. The abrasive material and generated abrasive debris are removed during injection by being inserted into the injection chamber through a second through hole and connected to the intake device to generate negative pressure in the injection chamber. The abrasive collecting means has a suction nozzle for sucking the mixture,
A sandblasting device characterized in that the mixture sucked by the suction nozzle is recovered, the abrasive material is separated from abrasive debris, and the abrasive material is supplied to the abrasive material supply source. (20) The sandblasting device according to claim 19, wherein the abrasive supply source comprises a shutoff valve that can be opened and closed by a switch provided adjacent to the blast head device. (21) The abrasive material supply source includes a blast tank connected to a compressed air supply source, a collection tank connected to the abrasive material recovery means to recover the collected abrasive material, and the blast tank and the collection tank. 20. The sandblasting apparatus according to claim 19, further comprising valve means disposed between the tanks to communicate and shut off the blast tank and the recovery tank. (22) The sandblasting apparatus according to claim 21, wherein the valve means is comprised of a valve means for communicating or blocking between the blast tank and the recovery tank. (23) The sandblasting device according to claim 22, wherein the collection tank is connected to the suction device to suck in the abrasive material collected by the abrasive material collection means. (24) The sandblasting device according to claim 23, further comprising valve means for selectively connecting the suction device to the recovery tank and the suction nozzle. (25) The sandblasting device according to claim 19, wherein the blast hood is formed of a damping steel plate. (26) The sandblasting device according to claim 19, wherein the blast hood is made of a sound-deadening material. (27) The sandblasting device according to claim 19, wherein the sealing means comprises a sealing piece that extends from the peripheral edge of the blast hood and tightly contacts and seals the surface to be polished. Device. (28) The sandblasting device according to claim 27, wherein the seal piece is made of rubber. (29) The sandblasting device according to claim 28, wherein the seal piece has a cylindrical portion that can be elastically deformed and come into close contact with the surface to be polished. (30) The sealing means is provided at least on the trailing side of the blast hood, and closely contacts the surface to be polished and works in conjunction with the sealing piece to maintain a sealed state between the blast hood and the surface to be polished. 20. Sandblasting device according to claim 19, characterized in that it consists of a sealing tongue ensuring that. (31) The sealing means is provided at least on the trailing side of the blast hood, closely contacts the surface to be polished, and works in conjunction with the sealing piece to maintain a sealed state between the blast hood and the surface to be polished. 29. Sandblasting device according to claim 28, characterized in that it consists of a sealing tongue ensuring that the (32) the suction nozzle consists of an inner and an outer tube;
20. Sandblasting device according to claim 19, characterized in that it defines a first suction passage and a second annular suction passage between the inner tube and the outer tube. (33) A partition wall partitioning the injection chamber and the recovery chamber is provided in the blast hood, a means for communicating between the injection chamber and the recovery chamber is provided in the partition wall, and the first absorption passage communicates with the injection chamber. 33. The sandblasting device according to claim 32, wherein the second absorption passage communicates with the recovery chamber. (34) The sandblasting device according to claim 19, wherein the abrasive material is a slag produced within a converter. (35) Claim 34, wherein the abrasive material has a Vickers hardness of 700±100HV.
Sandblasting equipment as described in section. (36) The sandblasting device according to claim 34, wherein the abrasive material is alkaline.