JP3021920B2 - Negative pressure suction blasting device for pipe inner surface - Google Patents

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 an inner surface of a pipe, and more particularly to a method of blasting a material to be blasted into a blasted pipe by negative pressure suction air, and floating and conveying the inside of the blast pipe to negative pressure suction air. The present invention relates to a negative pressure suction blasting apparatus for blasting, polishing, and grinding an inner surface of a pipe to be blasted.

[0002]

2. Description of the Related Art Conventionally, there are a high-pressure injection blast apparatus and a negative-pressure suction blast apparatus for blasting, polishing, and grinding the inner surface of a drawn steel pipe or the like.

FIG. 1 shows a first conventional high-pressure injection blasting apparatus.
2 will be described.

As shown in FIG. 12, in a first conventional high-pressure injection blasting apparatus, a compressor 1 for supplying high-pressure air for injecting and transporting a polishing material, and liquefied in high-pressure air at the time of high-pressure airization. An air dryer 2 for removing moisture from the air, an abrasive material tank 3 for dropping and mixing the abrasive material into the high-pressure air flow, and a nozzle for ejecting the abrasive material and high-pressure air for floating and transporting the abrasive material 4 is connected to one end of the blast pipe 6, and the other end of the blast pipe 6 is used for polishing, polishing, and grinding of the inner surface of the blast pipe 6. Receiving the finished blasting material and the high-pressure air that floats and transports the blasting material, a recovery tank 7 that collects part of the blasting material, and is still completely crushed even after lapping, polishing, and grinding Cyclone 8 that separates the clean abrasive material and blast air that have not been A dust collector 9 for separating blasting material or blasting dust from blast air, and a blasting material after polishing, polishing and grinding is sucked from the recovery tank 7 through the cyclone 8 and the dust collector 9. Then, an abrasive material / air discharge section 12 having a blower 10 for sending and discharging the air from which the abrasive material and abrasive dust have been removed to a silencer 11 is connected.

Prior to the description of the operation, general common basic items will be described.

[0006] First, blasting means removing scale from the inner surface of general steel pipes, oil country tubular goods, and other special pipes. Various abrasives are used as blasting materials.

Polishing refers to polishing of the inner surface of a stainless steel tube, aluminum tube, copper tube or the like, and various types of bead materials are used as a polishing material.

[0008] Grinding is to grind the inner surface of a thick steel pipe, special pipe, or the like, and uses a hard abrasive as a polishing material.

[0009] The wind speed of the air flow for transporting the blasting material in the blasted pipe is at least about 60 m / sec to at most 250 m / sec. The speed of the conveyed abrasive differs depending on the conditions, but its maximum speed reaches the same speed as the wind speed.

[0010] The unit volume air flow mixed with the abrasive material is
The upper limit of the amount of suspended material that can be suspended and transported in the blasted pipe is mainly determined by the wind speed of the air flow, and there are some fluctuations due to the specific gravity of the material to be cleaned and the size of the granules. Ratio), abrasive material / air (solid-gas ratio) = 1/100
About 0 is the upper limit.

The solid-gas ratio of the blast material to the air flow depends on the purpose (whether blasting, polishing, and grinding), the method of making the blasted tube, the material, the inner diameter, and the length. / 200
00 is used, but the above upper limit = abrasive material / air = 1
/ 1000, that is, the solid-gas ratio is larger,
Good polishing and grinding efficiency.

When the mixing amount is small, the abrasive material is uniformly dispersed and floated in the air flow, becomes a uniform flow, and is easily suspended and transported. When the solid-gas ratio is increased, the abrasive material is increased. Tends to become a pipe bottom flow (also referred to as a linear flow because the traces of polishing, polishing, and grinding become linear) near the bottom of the pipe, and when the solid-gas ratio is further increased, the pipe bottom flow causes a pulsation phenomenon,
Fluctuations in the flow direction occur in the pipe bottom flow, resulting in a sparse flow.

In the case of a uniform flow, the inner surface of the pipe is uniformly cleaned.
Polishing / grinding occurs only when the amount of the abrasive material is very small, and it takes a long time for the abrasive cleaning / polishing / grinding.

In the case of the pipe bottom flow, as a general phenomenon of the air flow in the pipe, when the velocity becomes higher than the turbulence critical velocity, the laminar flow becomes turbulent through the turbulence advance section, and the spiral swirling flow As the material advances, the abrasive material spirals on the inner surface of the pipe by centrifugal force, and moves while being polished, polished, and ground by the synergistic effect of speed and centrifugal force. When the material flows, the trajectory of the material to be cleaned becomes constant,
The grinding trace becomes a spiral linear shape (thus, in order to uniformly clean, polish and grind the entire inner surface of the tube, it is necessary to rotate the blasted tube around its axis, as described later. .).

In the case of a sparse / dense flow, the speed is slow in a dense portion, and a clogged state is apt to occur, so that it is difficult to use it for polishing, polishing and grinding.

Next, the operation of the first conventional high-pressure injection blasting apparatus will be described with reference to FIG. First, based on the manufacturing method, material, inner diameter, and length of the blasted tube 6 and the specifications of the blasting, polishing, and grinding, the air flow rate (determined from the required wind speed and the inner diameter of the pipe, Can be achieved.) And the operating conditions such as the static pressure, the type and amount of the abrasive material, etc. are determined. Normally, small-diameter pipes have low air volume and high pressure, medium-diameter pipes have medium air volume and medium pressure, and large-diameter pipes have large air volume and low pressure.
Static pressure at 10 Kg / cm ² within a high pressure injection (within -1 kg / cm ₂ in the negative pressure suction), to set a static pressure which can ensure air flow. The type and amount of the abrasive material are determined by the above general common basic matter, and a granular abrasive material such as garnet, alumina, or sand having a diameter of about 1 mm to 3 mm is used.
Usually, the working conditions are determined empirically, test blasting is performed under the working conditions, the working conditions are modified,
Determine the working conditions that will actually be used.

When the working conditions are determined, the compressor 1 is operated in accordance with the working conditions, and the generated moisture in the high-pressure air is removed by the air dryer 2 (to prevent the inner surface of the pipe from being corroded by the moisture). A predetermined polishing material is dropped and supplied from the polishing material tank 3 into the high-pressure air, and the high-pressure air floats and conveys a predetermined amount of the cleaning material per unit volume.
It is injected from the nozzle 4 into the blast pipe 6. The blast material suspended and conveyed in the high-pressure air reaches the other end of the blast pipe 6 while blasting, polishing, and grinding the inner surface of the pipe, and is jetted out together with the high-pressure air into the collection tank 7, where the velocity is increased. And the uncrushed abrasive material is collected here.
The air containing the crushed abrasive material and the abrasive dust is sucked into the blower 10, the relatively large crushed abrasive material and the abrasive dust are separated by the cyclone 8, and the small crushed abrasive material by the dust collector 9 is removed. Separates materials and grinding waste, blower 10 and silencer 1
It is discharged into the atmosphere via 1. However, as mentioned above,
Since the inside of the blasted tube 6 is only polished, polished and ground in a linear shape, it is necessary to rotate the blasted tube 6 about its axis.

The change in the static pressure of the high-pressure air in the case of the high-pressure injection blast device is shown in the lower part of FIG.

In the high-pressure injection blast device of the first conventional example, high-pressure air is blown out of the nozzle 4 into the blast pipe 6 at a speed higher than the turbulent flow critical speed, as shown in FIG. In addition, at the end of the blast pipe 6, the gas is jetted out as a laminar flow, and becomes turbulent after passing through the laminar flow region of the turbulent flow approach section. For this reason, in this laminar flow region, the abrasive cannot polish, polish, and grind the inner surface of the blasted tube 6, so that the polish, polish, and grind effects become zero. After the turbulent flow approaching section, a turbulent flow area is formed, and after the synergistic effect of the velocity and the centrifugal force is generated, the polishing, polishing, and grinding effects are generated. Therefore, in the high-pressure injection blasting apparatus, the end of the blast pipe 6 cannot be ground, polished, or ground.

In the high-pressure injection blasting apparatus of the first conventional example, when the inner diameter of the blasted tube 6 is large, the wind speed at the end side of the blasted tube is lower than the wind speed at which blasting, polishing and grinding can be performed. And the blasting, polishing, and grinding become impossible, and the uniform blasting, polishing, and grinding cannot be performed only by rotating the blasted tube 6.

As a countermeasure, in the high-pressure injection blast device of the second conventional example, as shown in FIG. 13, a plurality of injection hole nozzles 14 are attached to the nozzle 4 of the abrasive / air injection unit 5 at the tip. The small-diameter pipe 13 is connected, the small-diameter pipe 13 for insertion is inserted from one end to the other end of the large-diameter blasted pipe 6 ′, and high-pressure air for floating and transporting the abrasive is supplied from the multiple nozzles 14. The large-diameter blasted tube 6 'is pulled out while being jetted, and is polished, polished, and ground. However, even with this, it is only possible to perform polishing, polishing, and grinding of multiple lines,
In order to uniformly polish, polish, and grind the inner surface of the large-diameter blast pipe 6 ', a complicated and inefficient method of rotating the large-diameter blast pipe 6' is adopted. In this case, the high-pressure injection blasting device becomes complicated and expensive, the work efficiency is poor, and a space twice as long as the length L of the large-diameter blasted tube 6 'for inserting and extracting the small-diameter tube 13 for insertion is required. is necessary.

Further, the high-pressure injection blast device has a basic problem concerning the solid-gas ratio of the next abrasive. That is, when the abrasive material is mixed with the high-pressure air, the upper limit amount of the high-pressure air at which the abrasive material can float and convey the abrasive material is, as described above, about the abrasive material / air = 1/1000 by volume ratio, Even if the upper limit amount of the abrasive is mixed into the high-pressure air, the high-pressure air is injected into the blast pipe 6 after being mixed, and the high-pressure air expands and decompresses there and increases in volume. The amount of the abrasive material per unit volume of air (solid-gas ratio) becomes very small in inverse proportion to the expansion, and the effect of the abrasive / polishing / grinding is reduced accordingly. There is a problem that it takes a long time for grinding.

Further, the high-pressure injection blast device has a problem that the equipment cost and power consumption of the compressor for generating the high-pressure air are large, the cost is high, and there is a risk of rupture due to the high-pressure air.

Next, a third conventional suction vacuum blasting apparatus which solves the problems of the high pressure injection blasting apparatus will be described with reference to FIG.

As shown in FIG. 14, a conventional negative pressure suction blasting method (a method for blasting the inner surface of a pipe: Japanese Unexamined Patent Publication No.
In the third prior art negative pressure suction blasting device using the air suction device 29 incorporating a filter 32, the blasted material after the blasting is separated from the carrier air and accumulated in the accumulation tank 36. The blast pipe A is connected to one end of the blast pipe A by a pipe mounting part 33 via an air suction pipe 30 and an air suction pipe 30, and the abrasive material transport pipe 21 is connected to the other end of the blast pipe A through a nozzle 23. Pipe fitting 28
The air supply pipe 27 for supplying the negative pressure suction air sucked by the air suction device 29 for transporting the abrasive material to the blast pipe A is connected to the abrasive material transport pipe 21. ing. Further, above the air supply pipe 27, a hopper 24, an abrasive cleaning material outlet 25, and a regulating valve 26
Is provided.

Next, the operation of the negative pressure suction blast device of the third conventional example will be described with reference to FIG.

In FIG. 14, first, based on the manufacturing method, material, inner diameter and length of the blast pipe A, and the specifications of the blasting, polishing and grinding, the air volume of the negative pressure suction air (from the required wind speed and the inner diameter of the pipe). The purpose can be achieved if the air volume can be secured to this level or more.), The static pressure (within -1 kg / cm ₂ ), and the working conditions such as the type and amount of the abrasive material are determined. Normally, small-diameter pipes have a low air volume and high pressure, medium-diameter pipes have a medium air volume and medium pressure, and large-diameter pipes have a large air volume and low pressure. I can decide.

When the working conditions are determined, the air suction device 29 operates according to the working conditions, and the generated negative pressure suction force is applied to the separator 31, the air suction pipe 30, the blast pipe A, the nozzle 23, the abrasive material, and the like. A predetermined amount of negative pressure suction air for transporting the abrasive material is sucked from the air supply pipe 27 via the transport pipe 21. In this state, a predetermined polishing material from the cleaning material supply unit 22 falls in front of the air supply pipe 27, where it mixes with negative pressure suction air, and from there, the air suction device 29.
Floating / conveyed by negative pressure suction air toward.

The maximum speed of the abrasive material suspended and transported by the negative pressure suction air is the same as the wind speed of the negative pressure suction air in the blast pipe A (minimum 60 m / sec to maximum 250 m / sec). And the inner surface of the blast pipe A is cleaned, polished and ground.

The abrasive material suspended and conveyed by the negative pressure suction air reaches the other end of the blast pipe A while cleaning, polishing and grinding the inner surface of the pipe, and finishes the polishing, polishing and grinding. Most of the material is separated from the negative pressure suction air by the separator 31 through the air suction pipe 30, and the remaining polishing material after the polishing, polishing, and grinding is negatively suctioned by the filter 32 in the air suction device 29. Removed from air. The negative pressure suction air from which the abrasive material and the abrasive dust after the abrasive cleaning, polishing, and grinding are removed is discharged from the air suction device 29 into the atmosphere.

In the negative pressure suction blast device of the third conventional example, since the air velocity in the blast pipe is formed by suction of the air suction device 29, even if the blast pipe is a large-diameter pipe, the air flow in the blast pipe is not increased. There is no decrease in the wind speed, and the wind speed at which the blasting, polishing, and grinding can be performed can be maintained over the entire length from the ejection end to the suction end of the blast pipe. Further, when a predetermined abrasive from the abrasive supply unit 22 is mixed with the negative pressure suction air in front of the air supply pipe 27 to a maximum amount at which the negative pressure suction air can float and transport the abrasive, As a feature of the negative pressure suction blast device, the negative pressure suction air sucked by the air suction device 29 can make the wind speed close to the wind speed in the blast pipe A at the mixing position of the material to be cleaned. By changing the inner diameter of the apparatus at the mixing position of the material to be closer to the inner diameter of the blasted pipe, the change in static pressure during mixing of the abrasive material and passing through the blasted pipe A is much smaller than in the case of the high-pressure injection blasting apparatus. The negative pressure suction air can float and transport the blasting material A as it is in the blasted tube A as it is mixed to the upper limit amount where the blasting material can be floated and transported, and can efficiently perform blasting, polishing and grinding. . Therefore, in the case of a high-pressure injection blasting device, there are problems associated with high-pressure work, problems in that large-diameter pipes cannot be uniformly polished, polished, and ground over the entire length, and a decrease in the solid-gas ratio of the blasted material. The basic problem that long time is required for cleaning, polishing, and grinding can be solved.

[0032]

However, the negative pressure suction blast device of the third conventional example has a problem that it is necessary to stop the negative pressure suction blast device when removing the abrasive material from the receiver box. . An object of the present invention is to solve this problem and to provide a vacuum suction blasting device for the inner surface of a pipe, which can continuously remove the abrasive material from the receiver box during operation of the vacuum suction blasting device. I have.

[0033]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a negative pressure suction blasting device for an inner surface of a pipe according to the present invention separates an abrasive material and a negative pressure suction air at one end of a pipe to be blasted. The receiver box, the abrasive material discharging means for discharging the abrasive material separated from the receiver box, a cyclone, a dust collector, and a negative pressure suction unit having an air suction means for sucking negative pressure suction air are connected. The other end of the blast pipe is connected to a blasting material / air supply unit for supplying a blasting material and a negative pressure suction air for floating / conveying the blasting material into the blast pipe, and the negative pressure suction unit By the negative pressure suction action, the abrasive material is blown out from the cleaning material / air supply unit into the blast pipe together with the negative pressure suction air for floating and transporting the same, and the jetted material is floated by the negative pressure suction air.・ Conveyed laboratory By the material, the inner surface of the blasted pipe is polished, polished, and ground, and the blasted material after the blasting, polishing, and grinding, the negative pressure suction air, and the blast, polishing, and grinding debris are removed by the negative pressure suction unit. In the vacuum suction blasting device for the inner surface of the pipe that sucks out the inside of the blasted pipe and blasts the inner surface of the pipe, the blasting material discharging means includes a screw conveyor that discharges the blasting material from the bottom of the receiver box, and the screw conveyor. It is characterized by having a hopper tank for accumulating the conveyed abrasive material, a bypass tank connected to the hopper tank via an on-off valve, and an on-off valve between the bypass tank and the atmosphere.

[0034]

According to the vacuum suction blasting device for the inner surface of the pipe of the present invention, the abrasive material discharging means is provided at the bottom of the receiver box of the negative pressure suction unit, and the abrasive material discharging means is provided with the abrasive material from the bottom of the receiver box. Screw conveyor, and a hopper tank that accumulates the abrasive material carried out by the screw conveyor, a bypass tank connected to the hopper tank via an on-off valve, and an on-off valve between the bypass tank and the atmosphere. The screw conveyor continuously transports the abrasive material accumulated in the cyclone by the blasting work to the hopper tank, and when the abrasive material is accumulated in the hopper tank by a certain amount or more, an opening / closing valve between the hopper tank and the bypass tank. Open the hopper tank, transfer the abrasive material in the hopper tank to the bypass tank, and open and close the valve between the hopper tank and the bypass tank. Close. During this time, the hopper tank continuously receives the abrasive material that the screw conveyor carries out from the bottom of the receiver box to the hopper tank. The polishing material moved to the bypass tank is opened to the open / close valve and discharged to the atmosphere.

In this way, the polishing material can be continuously collected while the negative pressure suction blast device is continuously operated.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the negative pressure suction blast device of the present invention will be described with reference to FIGS.

In FIG. 1, the negative pressure suction blasting apparatus of the present embodiment comprises, at one end of a blast pipe A, a blasted material which has been polished, polished and grounded on the inner surface of the blast pipe A, and the blasted material. The receiver box X, which receives the negative pressure suction air for floating and transporting the material and separates the blast air, which has not been completely crushed after the blasting, polishing, and grinding, from the blast air, and the receiver box X Abrasive material transport means Y for transporting separated abrasive material
(The abrasive material is returned to the abrasive material tank 50, not shown.), A cyclone 51 for separating the crushed abrasive material or abrasive dust from the negative pressure suction air, a dust collector 52, and an abrasive material.・ Abrasive material after polishing and grinding and negative pressure suction air for floating and transporting the abrasive material are sucked from the blast pipe A through the receiver box X, the cyclone 51, and the dust collector 52. A negative pressure suction unit C having an air suction means 53 for sending and discharging the air from which the abrasive material and the abrasive dust have been removed to the silencer 54 is connected to the other end of the blast pipe A. And a negative pressure suction air for floating and transporting the same into the blast pipe A.
An air supply section B is connected, and the abrasive material / air supply section B is provided with an abrasive material / air turbulence means D. The air suction action by the negative pressure suction section C and the abrasive material / air turbulence means are provided. Due to the turbulence effect of D, the abrasive material and the negative pressure suction air for floating and transporting the abrasive material are ejected from the abrasive material / air supply unit B into the blast pipe A in a turbulent state. The inner surface of the blasted tube A is cleaned, polished and ground by the blast material which is ejected and floated and conveyed in the negative pressure suction air. The pressure suction air and the polishing / polishing / grinding debris are suctioned / discharged from the blast tube A. In this case, the abrasive material / air turbulence generating means D jets into the blast pipe A by disturbing the air flow and / or the abrasive material flow supplied into the abrasive material / air supply unit B. The flow of the immediately preceding abrasive material and the negative pressure suction air for floating and transporting the same are made to be turbulent in the abrasive material / air supply unit B, and the negative pressure suction for floating and transporting the abrasive material Air is blown out from the abrasive material / air supply unit B into the blast pipe A in a turbulent state.

The change in the negative static pressure of the negative pressure suction air of the negative pressure suction blast device is shown in the lower part of FIG.

FIG. 2 is a detailed view of the air suction means 53 of FIG.

Using one negative pressure suction blast device of the present embodiment, one blast pipe A from a small diameter pipe (small air volume and high pressure) to a large diameter pipe (large air volume and low pressure) or In order to blast the plurality of tubes at the same time, it is necessary to arbitrarily set the range of the air volume and the negative static pressure of the negative pressure suction air of the air suction means 53 over a wide range. For that purpose, it is effective to use a turbo blower for large air volume and low pressure and a vacuum blower or vacuum pump for small air volume and high pressure as the air suction means 53 alone or in various combinations.

In FIG. 2, two turbo blowers 55,
The on / off valves 59, 60, 61, and 62 can be used or stopped one by one, two in parallel, and two in series. FIG. 3 shows the operating characteristics in this case.

FIG. 3 shows a single turbo blower,
Air volume (m ³ / mi) when two units are used in parallel and two units are used in series
n) and the relationship between negative static pressure (-mmHg). In FIG. 3, the air flow from 0 to the maximum value cannot be used in a surging area because surging occurs when used in a negative pressure suction blast device. In the case of using two units in parallel, the surging area is eliminated, and in the case of using two units in series, the surging area becomes narrow. In addition to these effects, in this embodiment in which one unit is used alone, two units are arranged in parallel, and two units are used in series, the range of the negative air suction air volume and the negative static pressure of the air suction means 53 is set very wide. it can. Accordingly, one or many of the large-diameter pipes and the medium-diameter pipes can be blasted under appropriate conditions.

In this case, the turbo blowers 55, 5
No. 6 must be capable of operating at the same pressure.

In FIG. 2, two vacuum blowers or vacuum pumps can be used or stopped independently by the on-off valves 63 and 64, one by one or two in parallel. Since vacuum blowers and vacuum pumps have a negative static pressure limit of -760 mmHg, it is not necessary to use them in series.

FIG. 4 shows the operating characteristics in this case.

FIG. 4 shows a vacuum blower or a vacuum pump,
Airflow when using one unit alone and two units in parallel (m ³ /
min) and the negative static pressure (-mmHg). In the case of a vacuum blower or a vacuum pump, since there is no surging region, it is possible to cope with a considerably high pressure and a small air volume. Therefore, one or many of the small-diameter pipes and the medium-diameter pipes can be blasted under appropriate conditions.

In this case, the vacuum blowers or the vacuum pumps 57 and 58 need not be capable of operating at the same pressure.

In the parallel operation, the turbo blower 55 or 56 and the vacuum blower or vacuum pump 57 or 58,
There are combinations such as turbo blowers 55 and 56 and vacuum blowers or vacuum pumps 57 and 58, turbo blowers 55 and 56 in series and vacuum blowers or vacuum pumps 57 and 58 alone or in parallel. Become wider. In this case, it is not necessary that the turbo blower and the vacuum blower or the vacuum pump can operate at the same pressure.

The on-off valves 59 and 60 can have a damper function in addition to the function of the on-off valves.

The air in each circuit is silencer 56,
It is discharged to the atmosphere via 57, 58, 59.

FIGS. 6 to 8 are detailed views of the abrasive material / air turbulence generating means D of FIG. Next, the details of the abrasive material / air turbulence generator D will be described.

In FIG. 6, at one end of the blast pipe A,
A gradient pipe F whose inner diameter is reduced in the direction of the blast pipe A is attached, and an inner diameter d '(about 1.5 times the inner diameter d of the blast pipe A) of the blast pipe A is attached to the gradient pipe F. If it can be installed, the inner diameter d 'should be closer to d in order to reduce the change in wind speed in the abrasive material / air supply section B and in the blasted pipe A.) A cylindrical blasting material / air supply section B having a length S is connected to the blasting material / air supply section B. H, and slightly above the bulge H,
An abrasive material eccentric falling port P for dropping the abrasive material K in a direction deviated from the axis of the abrasive material / air supply unit B is provided, and the abrasive material K falling from the abrasive material eccentric falling port P is provided. In response to the abrasive material
The opening J leading into the air supply unit B is cleaned with the abrasive material / air supply unit B.
The abrasive material K received in the opening J falls along the inner wall of the abrasive material / air supply part B, and floats and is conveyed to the negative pressure suction air. It rises up along the inner wall.

The obstruction protrusion I is provided at this raised position. The combination of the eccentric falling port P and the opening J has a clockwise rotation and a counterclockwise rotation. Further, a baffle projection E is provided inside the front end of the opening J so that the eccentric material dropping port P reciprocates back and forth along the opening J. Further, the insertion length of the baffle protrusions I and E is made variable.

In FIG. 7, at least one opening / closing air inlet N which repeats opening / closing with time is provided on the side surface of the polishing material / air supply section B. In the case of plural cases, this is the same as providing a negative pressure air inlet moving with time.

In FIG. 8, an air inlet M is provided at the rear end of the abrasive / air supply unit B.

Next, the operation of the abrasive material / air turbulence generating means D shown in FIGS. 6 to 8 will be described.

In FIG. 6, since the inside diameter of the gradient pipe F is reduced in the direction of the blast pipe A, the speed of the negative pressure suction air sucked by the negative pressure suction section C increases in the gradient pipe F. Then, exceeding the critical velocity causing turbulence, the abrasive material K and the negative pressure suction air that floats and conveys the abrasive material K in the blast pipe A easily become turbulent.

Further, a bulging portion H provided at the rear end of the cleaning material / air supply portion B in a direction opposite to the connection direction of the blast pipe A is provided.
Temporarily removes a part of the flow of the negative pressure suction air and the polishing material K flowing into the inside of the polishing material / air supply unit B which is in a negative pressure.
After the negative pressure of the inflated portion is drawn, the blast tube A
Turbulence is caused in the direction of connection, and the blasting material K and the negative pressure suction air carrying it are brought into a turbulent state. In addition, the polishing material K may accumulate below the bulging portion H. In order to prevent this, an inclined plate G is preferably provided.

In addition, the eccentric falling port P for the abrasive material is provided with the abrasive material K,
The abrasive material / air supply unit B is dropped in a direction deviated from the axis of the abrasive material / air supply unit B, and the dropped abrasive material K is moved along the inner wall of the abrasive material / air supply unit B. Because of the rotation, the blasting material K and the negative pressure suction air that floats and conveys the blasting material K are likely to be turbulent.

An eccentric material dropping port P for dropping the abrasive material K in a direction deviated from the axis of the abrasive material / air supply unit B
And the abrasive K falling from the eccentric drop P
With the rectangular opening J which is long in the axial direction of the abrasive material / air supply unit B, the dropped abrasive material K rotates along the inner wall of the abrasive material / air supply unit B and becomes turbulent. The blasting material K and the negative pressure suction air that floats and conveys the same are brought into a turbulent state.

Further, the baffle protrusions I and E obstruct the flow of the abrasive material K and the negative pressure suction air for suspending and transporting the same, thereby causing turbulence, and suspending and transporting the abrasive material K and the same. The negative pressure suction air is brought into a turbulent state. The baffle may be provided anywhere in the cleaning material / air supply unit B. For example, it may be provided in the gradient tube F or at an end thereof.

The reciprocating movement of the abrasive material eccentric falling port P back and forth along the opening J means that the abrasive material K always moves along the path in which the abrasive material K floats and is conveyed in the negative pressure suction air. This is effective in uniformly polishing, polishing, and grinding the entire surface inside the blast pipe A.

Further, at least one opening / closing air inlet N which repeats opening and closing with time is provided on a side surface of the cleaning material / air supply section B, and an air flow is provided at a rear end of the polishing material / air supply section B. The provision of the inlet M means that the negative pressure suction air flow is made turbulent by creating negative pressure suction air flows in various directions in the abrasive material / air supply section B, or a plurality of negative pressure suction air flows are provided. Interfere with each other and turbulence the entire negative pressure suction air flow.

The cleaning material / air turbulence generating means D of the present invention is not limited to the structure of the above-mentioned embodiment, but may be any turbulent flow between the cleaning material K and the negative pressure suction air carrying it. Various aspects are possible and can be designed freely.

FIGS. 9 to 11 are detailed views of the receiver box X of FIG.

Using one negative pressure suction blasting apparatus of this embodiment, one blast pipe A from a small diameter pipe (small air volume high pressure) to a large diameter pipe (large air volume low pressure) is used. In order to simultaneously blast the plurality of tubes, it is necessary to be able to arbitrarily set the range of the air volume and the negative static pressure of the negative pressure suction air of the air suction means 53 as described above, The negative pressure suction force is simultaneously applied to one or more of the blast pipes A from the small diameter pipe (small air amount high pressure) to the large diameter pipe (large air amount low pressure), and the abrasive material is also cleaned. And a negative pressure suction air for transporting the same, a polishing material is collected, and a receiver box X for discharging the negative pressure suction air to the atmosphere is required.

FIG. 9 shows that the negative pressure suction force of the air suction means 53 is simultaneously applied to each of the blast pipes A from the small diameter pipe (small air amount high pressure) to the large diameter pipe (large air amount low pressure). Or a receiver box X acting on a plurality of them,
FIG. 3 is a detailed view of an abrasive cleaning material transporting means Y for transporting the abrasive cleaning material K separated by a receiver box X;

In FIG. 9, the receiver box X is
A plurality of dummy pipes 70 (dummy pipes) connected to the blast pipe A and having discharge holes 69 for discharging the polishing material K and the negative pressure suction air for floating and transporting the same downward into the receiver box X. The inner diameter of 70 is
1.5 to 2 times the inner diameter d of ), A first-stage box 71, a skirt 74 of the first-stage box 71, and a second
Step box 72 and skirt 75 of second step box 72
From the upper end of the first-stage box 71
And a connection pipe 73 connected to
A screw conveyor 76 for carrying out the abrasive material K separated and accumulated in the second stage box 72 from the lower end of the second stage box 72, a hopper tank 77 for accumulating the abrasive material K carried out by the screw conveyor 76, Bypass tank 79 connected to hopper tank 77 via on-off valve 78
And an on-off valve 8 provided between the bypass tank 79 and the atmosphere
0.

The above-mentioned plurality of dummy pipes 70 correspond to FIG.
As shown at 0, they are arranged horizontally side by side.

The operation of the receiver box X is shown in FIG.
It will be described based on. Cleaning / polishing inside the blasted tube A
The ground abrasive material K and the negative pressure suction air for floating and transporting the abrasive material K are discharged downward from the discharge holes 69 of the plurality of dummy pipes 70, and the speed thereof suddenly decreases, and The cleaning material conveying force of the compressed air is lost, and a part of the reusable cleaning material K which is still in a granular form and falls down to the lower portion of the second-stage box 72. The negative pressure suction air is
The negative pressure suction air, which has lost most of the abrasive material K, is discharged downward from the discharge hole 69 in the vertical center axis of the step box 71 and the second step box 72. And rises along the side surface of the first-stage box 71.
A second-stage box 72 is provided on the upper side of the second-stage box 72.
Most of the abrasive material K remaining and conveyed in the negative-pressure suction air is blocked by the skirt 75 of the second-stage box 72 and falls to a lower portion of the second-stage box 72. I do. Next, the negative-pressure suction air from which the cleaning material K has been separated twice rises along the side surface of the first-stage box 71. The first side box 71 has a first side
There is a skirt 74 of the step box 71, and most of the abrasive material K remaining and conveyed in the negative pressure suction air is blocked by the skirt 74 of the first step box 71 and Fall to the bottom. When the negative-pressure suction air reaches this position, almost all of the cleaning material K in the negative-pressure suction air falls to the lower part of the second-stage box 72, and the cleaning material K, which has been finely divided into dust, and the cleaning material K Only the debris is conveyed to the negative pressure suction air and sent to the cyclone 51.

In this case, as shown in FIG. 10, when the number of dummy pipes 70 arranged horizontally and horizontally is increased and the first-stage box 71 is widened, the dummy pipes arranged at both ends are increased. There is a difference between the negative pressure suction force acting on the blast pipe A connected to 70 and the negative pressure suction force acting on the blast pipe A connected to the dummy pipe 70 arranged at the center. . To prevent this,
As shown in FIG. 11, a separate plate 81 is provided in the first-stage box 71 to form a separate first-stage box 71 '. At the top of each of the separated first-stage boxes 71 ',
A connection tube 73 to the cyclone 51 is connected.

The abrasive material K accumulated in the lower portion of the second-stage box 72 is carried out by the next abrasive material carrying means Y.

In the abrasive material discharging means Y, the abrasive material K stored in the receiver box X is transferred to the screw conveyor 7.
At 6, it is carried out to the hopper tank 77. When the polishing material K is accumulated in the hopper tank 77 by a certain amount or more, the on-off valve 80
Is closed, the on-off valve 78 is opened, the abrasive material K in the hopper tank 77 is transferred to the bypass tank 79, and the on-off valve 78 is closed. During this time, the hopper tank 77 continuously receives the abrasive material K carried out by the screw conveyor 76. The cleaning material K that has moved to the bypass tank 79 is opened into the atmosphere by opening the on-off valve 80. In this way, the polishing material K can be continuously collected while the negative pressure suction blast device is continuously operated. Although this collected abrasive material K is not shown,
It is sent to the abrasive material tank 50 and reused.

As described above, the negative pressure suction blast device of this embodiment can take out the abrasive material from the cyclone during the operation of the negative pressure suction blast device, thereby enabling continuous operation.

[0075]

As described above, in the vacuum suction blast apparatus for the inner surface of the pipe according to the present invention, the polishing material discharge means includes a screw conveyor for discharging the cleaning material from the bottom of the receiver box, and the polishing conveyed by the screw conveyor. By having a hopper tank for accumulating materials, a bypass tank connected to the hopper tank via an on-off valve, and an on-off valve provided between the bypass tank and the atmosphere, during operation of the negative pressure suction blast device, The polishing material can be taken out, continuous operation can be performed, and the effect of improving work efficiency is exhibited.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a detailed view of the air suction means of FIG.

FIG. 3 is an operation diagram of FIG. 2;

FIG. 4 is an operation diagram of FIG. 2;

FIG. 5 is an operation diagram of a conventional example.

FIG. 6 is a detailed view of an abrasive material / air supply unit and an abrasive material / air turbulence generation unit of FIG. 1;

FIG. 7 is a detailed view of the abrasive material / air supply unit and the abrasive material / air turbulence generating means of FIG. 1;

FIG. 8 is a detailed view of an abrasive material / air supply unit and an abrasive material / air turbulence generating unit of FIG. 1;

FIG. 9 is a detailed side view of the receiver box and the abrasive material discharging means of FIG. 1;

FIG. 10 is a partially detailed plan view of the receiver box of FIG. 1;

FIG. 11 is a partial detailed side view of the receiver box of FIG. 1;

FIG. 12 is a configuration diagram of a first conventional example.

FIG. 13 is a configuration diagram of a second conventional example.

FIG. 14 is a configuration diagram of a third conventional example.

[Description of Signs] A Blasted pipe B Polishing material / air supply section C Negative pressure suction section 51 Cyclone X Receiver box Y Polishing material discharge means 76 Screw conveyor 77 Hopper tank 78, 80 Open / close valve 79 Bypass tank

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B24C 9/00 B24C 3/16 B24C 3/32

Claims (1)

(57) [Claims] 1. A receiver box for separating an abrasive material and a negative pressure suction air at one end of a blast pipe, an abrasive material discharging means for discharging the abrasive material separated by the receiver box, a cyclone, A negative pressure suction unit having a dust collector and air suction means for sucking the negative pressure suction air is connected, and the other end of the blast pipe is a negative material for floating and transporting the abrasive material in the blast pipe. A cleaning material / air supply unit for supplying pressured air and air is connected, and a negative pressure suction operation by the negative pressure suction unit causes the abrasive material to float / transport from the cleaning material / air supply unit. The blasted pipe is jetted into the blast pipe together with the negative pressure suction air to be blasted, and the blasted pipe inner surface is polished, polished, and ground by the blasting material which is jetted and suspended and conveyed by the negative pressure suction air. Polishing
In the negative pressure suction blasting device for the inner surface of the pipe, the negative pressure suction part sucks out the blasted material after the grinding, the negative pressure suction air, and the polishing / polishing / grinding dust from the inside of the blasted pipe to blast the inner surface of the pipe. A screw conveyor for carrying out the abrasive material from the bottom of the receiver box, a hopper tank for storing the abrasive material carried out by the screw conveyor, and a bypass connected to the hopper tank via an on-off valve. A negative pressure suction blast device for an inner surface of a pipe, comprising a tank, an on-off valve between a bypass tank and the atmosphere.