JP2018089748A - Blasting method and device for internal surface of tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blasting device for the internal surface of a tube, by which action for conveyance of a grinding material can speedily be caused over the entire tube being processed, regardless of the size of the pipe being processed.SOLUTION: A blasting device comprises: a suction device 7 that sucks air in a tube from the downstream end P1 of a pipe P being processed; and an injector 3 that injects a grinding material and air into the tube from the upstream end P2 of the pipe P in a sealed state. By virtue of this, strong forces for causing the grinding material and air to flow from an upstream side to a downstream side in a pipe are simultaneously act from both ends P1, P2 of the pipe P being processed. Therefore, the grinding material is securely conveyed over the entire length of the pipe P being processed, even in a case where it is difficult to cause action for conveyance of a grinding material over the entire length of the pipe P in a short time only with a negative-pressure suction force, such as a case where the inside diameter of the pipe P being processed is short or the entire length L of the pipe is long.SELECTED DRAWING: Figure 1

Description

The present invention relates to a pipe inner surface blasting method and apparatus for polishing, polishing and grinding the inner surfaces of various pipes (processed pipes), and a pipe inner surface blasting system including the apparatus.

High-pressure injection blasting method and negative-pressure suction blasting method are used as blasting methods for the inner surface of pipes such as steel pipes (processed pipes) for scouring, polishing, grinding, etc. (hereinafter simply referred to as “scouring”). Is known. The high-pressure injection blasting method is a method in which air and a cleaning material are blown into a pipe to be processed at a high pressure (see FIG. 12 and [0004] to [0018] in Patent Document 1). In this method, the abrasive is sucked into the pipe by making the inside of the pipe to be treated into a negative pressure (see FIG. 14 and [0026] to [0032] in Patent Document 1). From various viewpoints such as economy, labor-saving / energy-saving, safety, maintainability, environmental hygiene, etc., it is generally said that the negative pressure suction blast method is generally superior today.

JP-A-7-1335 JP 50-1562 A JP 7-227762 A

However, when the inner diameter of the tube to be processed is small or the entire length of the tube to be processed is long, the pressure loss becomes large, so that it is difficult for the conveying action of the abrasive material due to negative pressure to reach the entire length of the tube to be processed. There's a problem. If time is taken for the negative pressure suction, there may be a case where the conveying action of the scouring material can be exerted over the entire length of the tube to be treated. However, the scouring process efficiency is lowered and workability is deteriorated.

In a conventional method for blasting the inner surface of a pipe, as shown in Patent Document 2, the air in the pipe to be cleaned 22 is sucked from the downstream end of the pipe to be cleaned 22 and the inside of the pipe to be cleaned 22 There is also known a system in which compressed air is supplied by the nozzle 11 in addition to the abrasive 14 from the upstream end of the polished pipe 22.

However, in this case, as shown in FIG. 1 of Patent Document 2, the upstream end 24 of the transport pipe 6 connected to the upstream end of the polished pipe 22 is open, and the opening 24 Atmosphere is sucked from. For this reason, the compressed air supplied from the nozzle 11 only plays a role of assisting the negative pressure suction action by the dust collector 18. Therefore, when the length of the pipe to be cleaned is very long with respect to the diameter of the pipe to be polished 22, it takes time for the conveying action of the polishing material to reach the entire length of the pipe to be polished 22. Therefore, it is difficult to say that the above problem is sufficiently solved.

Further, as another example of the blasting method of the pipe inner surface, as described in [0028] of Patent Document 3, “the blower 23 of the scouring machine 15 sucks the negative pressure into the pipe 13 to be processed from the receiver tank 22 side. The compressed air nozzle 24 blows the swirled compressed air from the suction head 21 side into the processing tube 13. Thereby, the swirling flow of the polishing material flowing from the one end 13A to the other end 13B of the processing tube 13 is processed. The inner surface of the tube 13 is sharpened. "

However, in Patent Document 3, as seen from the description of [0023], [0024] and FIGS. 2 and 3, the negative pressure suction force acts effectively, and the abrasive is removed from the abrasive tank. It is considered that the upper portion of the suction head 21 is opened upward so that can be smoothly supplied. The compressed air supplied from the compressed air nozzle 24 is only for creating a swirling flow. Therefore, when the length of the pipe to be processed is very long with respect to the diameter of the pipe to be processed, it takes time for the polishing material to reach the entire length of the pipe to be processed. Is difficult to resolve.

The present invention has been made in view of the above circumstances. The present invention draws the abrasive conveying air flow from the upstream end of the pipe to be processed due to the problem of pressure loss even with a high-power vacuum blower used in a conventional negative pressure suction pipe inner surface blasting device. This is effective when performing a blasting process on a tube to be processed that has a small inner diameter or a long overall length. The present invention is intended to propose a method and apparatus for blasting the inner surface of a pipe, and a blasting system for a pipe inner surface, which can be applied quickly.

In order to solve the above-mentioned problem, the blasting method of the pipe inner surface according to the present invention sucks air in the pipe from the downstream end of the pipe to be processed and seals the abrasive and air from the upstream end of the pipe to be processed. And pumping into the pipe (claim 1).

According to the method of the present invention, the air in the pipe is sucked from the downstream end of the pipe to be processed, and the abrasive and the air are pumped into the pipe in a sealed state from the upstream end of the pipe to be processed. As a result, a strong force that causes the abrasive to flow from upstream to downstream in the pipe acts simultaneously from both ends of the pipe to be processed. For this reason, when the inner diameter of the tube to be processed is small or when the entire length of the tube to be processed is long, it is difficult to exert the conveying action of the abrasive material over the entire length of the tube to be processed only by the negative pressure suction action. Even so, the abrasive is reliably conveyed over the entire length of the tube to be processed. As a result, regardless of the size of the tube to be processed, the scouring effect can be exerted efficiently over the entire length of the tube to be processed.

According to the method of the present invention, unlike the ones in Patent Documents 2 and 3, the abrasive and the air are pumped into the pipe in a sealed state from the upstream end of the pipe to be treated, and therefore coupled with the suction of the air in the pipe. The abrasive is transported efficiently and reliably in the pipe.

As a preferred embodiment, the pipe to be processed, which is a straight pipe, substitutes specific numerical values for P, γ, and V (80 m / s or more) in the following formula and either L or D The aspect which is the size below D obtained by substituting a specific numerical value to L or L or more is illustrated (Claim 2).
L / D = 2P / (0.02 × γ × V ² )
L: Length of pipe to be processed m
D: Inner diameter (diameter) of the pipe to be processed
P: Required pressure Pa
γ: air density kg / m ³
V: Flow velocity in the pipe to be processed m / s

A tube to be processed having a size satisfying this condition is suitable as an application target of the blasting method according to the present invention.

A blasting device for a pipe inner surface according to the present invention includes a suction device for sucking air in a pipe from a downstream end of the pipe to be processed, and a cleaning material and air are injected into the pipe in a sealed state from the upstream end of the pipe to be processed. And an injection device that performs (claim 3).

According to the apparatus of the present invention, air in the pipe is sucked from the downstream end of the pipe to be processed by the suction device, and the abrasive and air are pumped into the pipe in a sealed state from the upstream end of the pipe to be processed by the spraying device. Is done. As a result, a strong force for causing the abrasive and air to flow from upstream to downstream in the pipe acts simultaneously from both ends of the pipe to be processed. For this reason, when the inner diameter of the tube to be processed is small or when the entire length of the tube to be processed is long, it is difficult to exert the conveying action of the abrasive material over the entire length of the tube to be processed only by the negative pressure suction action. Even so, the abrasive is reliably conveyed over the entire length of the tube to be processed. As a result, regardless of the size of the tube to be processed, the scouring effect can be exerted efficiently over the entire length of the tube to be processed.

As a preferred embodiment, the pipe to be processed, which is a straight pipe, substitutes specific numerical values for P, γ, and V (80 m / s or more) in the following formula and either L or D The aspect which is a size below D or L obtained by substituting a specific numerical value for is illustrated.
L / D = 2P / (0.02 × γ × V ² )
L: Length of pipe to be processed m
D: Inner diameter (diameter) of the pipe to be processed
P: Required pressure Pa
γ: air density kg / m ³
V: Flow velocity in the pipe to be processed m / s

A tube to be processed having a size satisfying this condition is suitable as an object to be cleaned by the blasting apparatus according to the present invention.

As a preferred embodiment, the injection device includes a mixing unit that mixes the scouring material and the air upstream of an upstream end of the processing target pipe, stores the scouring material, and mixes the scouring material. A sealed server tank for supplying the abrasive to the unit, a pumping device for pumping air into the mixing unit and the server tank, and the server so as to be equal to or higher than the internal pressure of the mixing unit And a regulator for controlling the internal pressure of the tank (claim 5). In this case, since the internal pressure of the server tank is controlled so as to be equal to or higher than the internal pressure of the mixing unit, the abrasive is smoothly supplied from the server tank to the mixing unit.

In the pipe inner surface blasting system according to the present invention, a blasting device is provided on each of an inlet side and an outlet side along a transfer line of a pipe to be processed, and the inlet blasting apparatus is configured to send air in the pipe from one end of the pipe to be processed. An inlet-side suction device that sucks in, and an inlet-side injection device that injects the abrasive and air as a swirling flow into the pipe in a sealed state from the other end of the pipe to be processed. A discharge side suction device for sucking air in the pipe from the other end of the pipe to be processed, and a discharge side for injecting the polishing material and air into the pipe in a sealed state from the one end of the pipe to be processed And an injection device (claim 6).

The pipe inner surface blasting system according to the present invention is intended to solve the problem that the effect of the cleaning process on the inner surface of the pipe is different between both ends of the pipe to be processed in the cleaning by the swirling flow of the polishing material. It is.

According to the present invention, the tube to be processed is subjected to the blasting process by the inlet blast device, and then transferred along the transfer line of the tube to be processed, and the blasting process is performed by the outlet blast device. .

In the inlet-side blasting apparatus, air in the pipe is sucked from one end of the pipe to be processed by the inlet-side suction apparatus, and the abrasive and air are sealed in the pipe in a sealed state from the other end of the pipe to be processed by the inlet-side injection apparatus. Are injected as a swirling flow. As a result, a strong force for causing the abrasive and air to flow in the tube from the other end of the tube to be processed to one end simultaneously acts from both ends of the tube to be processed. For this reason, when the inner diameter of the tube to be processed is small or when the entire length of the tube to be processed is long, it is difficult to exert the conveying action of the abrasive material over the entire length of the tube to be processed only by the negative pressure suction action. Even so, the abrasive is reliably conveyed over the entire length of the tube to be processed.

In the outlet blast device, air in the pipe is sucked from the other end of the pipe to be processed by the outlet suction apparatus, and the abrasive and air are sealed in the pipe in a sealed state from one end of the pipe to be processed by the outlet jet apparatus. Are injected as a swirling flow. As a result, a strong force for causing the abrasive and air to flow in the pipe from one end to the other end of the pipe is simultaneously applied from both ends of the pipe. For this reason, when the inner diameter of the tube to be processed is small or when the entire length of the tube to be processed is long, it is difficult to exert the conveying action of the abrasive material over the entire length of the tube to be processed only by the negative pressure suction action. Even so, the abrasive is reliably conveyed over the entire length of the tube to be processed.

In the present invention, a single pipe to be treated is subjected to the blasting process twice with the action directions of suction and jetting (the flow direction of the scouring material) reversed. Thereby, it becomes possible to equalize the effect of the blasting process by the swirling flow between both ends of the pipe to be processed. In addition, since the inlet blasting device and the outlet blasting device are arranged on the inlet side and the outlet side along the transfer line of the pipe to be processed, it is necessary to invert the pipe to be processed in performing the two blasting processes. Absent. Therefore, work can be performed easily and processing efficiency is good.

As one preferred embodiment, the entry-side blast device is located on the other end side of the tube to be treated and stores an abrasive for supplying the material to be fed into the tube to be treated; An inlet-side receiver tank that is located on the one end side of the pipe to be processed and receives the polishing material that has passed through the pipe to be processed, and the outlet blast device is located on the one end side of the pipe to be processed. And a delivery-side server tank that stores a polishing material to be supplied into the processing pipe, and a delivery-side receiver that is located on the other end side of the processing pipe and receives the polishing material that has passed through the processing pipe. A tank, wherein the inlet receiver tank and the outlet server tank are coupled so that the abrasive in the inlet receiver tank can be transferred into the outlet server tank, and the outlet receiver tank The abrasive material in the And the exit-side receiver tank and entering-side server tank so that it can transfer to the side server tank is characterized in that it is connected (claim 7).

According to this embodiment, the polishing material that has finished polishing the inner surface of the tube to be processed by the inlet blast device is reintroduced into the outlet blast device, and the inner surface of the tube to be processed is cleaned by the outlet blast device. The polishing material that has finished is re-introduced into the inlet blasting device, and this is repeated. Since the abrasive is used to circulate repeatedly, it is economical.

Furthermore, the incoming receiver tank that constitutes the incoming blast device and the outgoing server tank that constitutes the outgoing blast device are both on one end side of the pipe to be processed. Further, both the outgoing receiver tank constituting the outgoing blast device and the incoming server tank constituting the incoming blast device are on the other end side of the pipe to be processed. For this reason, the polishing material transfer path between the inlet receiver tank and the outlet server tank and the abrasive transfer path between the outlet receiver tank and the inlet server tank can both be short and sharpened. The layout of the scavenging material transfer path can also be simplified. Therefore, the arrangement cost of the scouring material transfer path can be saved, which is more economical.

It is a lineblock diagram of the blasting device of the pipe inner surface concerning one embodiment of the present invention. It is an expanded sectional view of the injection apparatus in the blast apparatus of FIG. 1 is a schematic plan view of a tube inner surface blast system according to an embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, a blasting device 1 for an inner surface of a pipe according to an embodiment of the present invention sucks air in the pipe from a downstream end P1 of a pipe to be processed P and also uses an abrasive or a polishing material involved in the blasting. A suction recovery device 2 that recovers scraps, and an injection device 3 that injects the abrasive and air from the upstream end P2 of the processing pipe P into the pipe in a sealed state.

The injecting device 3 has a polishing operation position (position shown in FIG. 1) that is in close contact with the upstream end P2 of the processing pipe P, and a retreat position (leftward from the position shown in FIG. 1) away from the upstream end P2 of the processing pipe P. The position can be moved freely. And after connecting the downstream end P1 of the to-be-processed pipe P with respect to the suction collection | recovery apparatus 2, the injection apparatus 3 and suction are moved by moving the injection apparatus 3 in a retracted position to the cleaning work position shown in FIG. The to-be-processed pipe | tube P is hold | maintained between the collection | recovery apparatuses 2. FIG. In this holding state, the to-be-processed pipe P is subjected to the blasting process. When the polishing process is completed, the processing pipe P is released by moving the injection device 3 to the retracted position, and the processing pipe P is transferred along the transfer line (direction perpendicular to the paper surface of FIG. 1). To do.

Moreover, the injection device 3 can be moved largely along the length direction of the pipe P to be processed, for example, by being mounted on the carriage 35. With this configuration, it is possible to cope with the blasting process of the pipes P having different lengths.

The injection device 3 includes a server tank 4, a mixing unit 5, and a pressure feeding device 6. The server tank 4 stores a polishing material to be supplied into the processing pipe P, and supplies the polishing material to the mixing unit 5. The mixing unit 5 mixes the abrasive and the air upstream of the upstream end P2 of the pipe P to be processed. The pressure feeding device 6 supplies compressed air into the mixing unit 5 and the server tank 4. As the pumping device 6, for example, a blower such as a roots blower having a discharge specification can be used in addition to a compressor. The abrasive and the air for conveyance mixed in the mixing unit 5 flow at a high speed in the pipe P from the upstream P2 to the downstream end P1, and in this flow process, the abrasive is the inner surface of the pipe P to be processed. Clean up. The polishing material involved in the cleaning is suctioned with negative pressure by the suction recovery device 2 together with the air for conveyance, flows out from the downstream end P1 of the pipe P to be processed, and is recovered.

The suction recovery device 2 includes a suction device 7 and a recovery device 8. As the suction device 7, for example, a vacuum blower such as a dry or wet roots blower or a vacuum pump is used. A recovery device 8 is disposed between the suction device 7 and the downstream end P1 of the processing pipe P. The recovery device 8 recovers the polishing material involved in the cleaning of the inner surface of the pipe P to be processed, the polishing material crushed by participating in the cleaning, the polishing scraps, and the like. The collection device 8 includes a receiver tank 9, a cyclone separator 10, and a dust collector 11 in order from the upstream side. The receiver tank 9 receives the scouring material that has finished scouring and accommodates a part of the scouring material. The cyclone separator 10 separates the granular polishing material that has not been completely crushed even after the polishing and the air for conveyance. The dust collector 11 separates the crushed abrasive or abrasive scraps from the air for conveyance. The clean air from which these foreign substances have been removed is released into the atmosphere through the exhaust silencer 12 disposed on the exhaust side of the suction device 7.

It is not sufficient for the suction device 7 to have a suction force necessary for recovering the polishing material involved in the polishing. For normal pipes to be processed, such as those used in conventional negative pressure suction pipe inner surface blasting equipment, it is possible to generate an abrasive conveying airflow in the entire pipe in a short time. It is necessary to have a negative pressure suction force of In other words, the pipe inner surface blasting apparatus 1 according to the present embodiment has a high output suction device such as that used in the conventional negative pressure suction type pipe inner surface blasting apparatus, and is subject to pressure loss. This is an effective apparatus for performing the blasting process on the pipe P having a small inner diameter or a long total length so that the blast material conveying air current cannot be drawn from the upstream end P2 of P.

The relationship between the inner diameter D and the length L of the pipe P to be processed, which is suitable for performing the blasting process with the blasting device 1 on the pipe inner surface according to the present embodiment, can be determined as follows.

Generally, an air volume Q (m ³ / min) within a straight pipe (inherent loss coefficient ζ = 0.02 × L / D) having an opening area A (= πD ² × 1/4) (m ² ). The pressure P (Pa) required for flowing the air of the straight pipe is the inner diameter (diameter) D (m) and length L (m) of the straight pipe, and the air density γ (kg / m ³ ) (for example, a large 20 ° C. Atmospheric air density γ = 1.2 kg / m ³ ) and air velocity V (= Q / 60A) (m / s) in the pipe are determined as follows (Darcy-Weissbach equation).
^{P = ζ · γ · V 2} /2 ······ (1)
P = 0.02 × L / D × γ × V 2/2 ······ (2)

Where P: Required pressure (pressure loss) Pa
A: Cross section of straight pipe m ²
(A = πD ² × 1/4)
Q: Air volume m ³ / min
V: Flow velocity (V = Q / 60A) m / s
γ: air density kg / m ³
(Air density γ = 1.2 kg / m ^{3 at} 20 ° C atmospheric pressure)
ζ: loss factor specific to straight pipe (ζ = 0.02 × L / D)
D: Inner diameter (diameter) of straight pipe m
L: Length of straight pipe m

Incidentally, the suction device 7 has an inherent limit value for the suction pressure. For example, when a dry roots blower is used as the suction device 7, the suction pressure is limited to 60 kPa, when a wet roots blower is used, the suction pressure is limited to 95 kPa, and when a vacuum pump is used, the suction pressure is limited to 101.3 kPa. is there. When the required pressure exceeds these limit values, the blast device 1 for the pipe inner surface according to the present embodiment is effective.

Therefore, in the equation (2), the velocity V of the air passing through the pipe is set to a desired value (preferably, V = 80 m / s or more, as will be described later), and exceeds the limit value. If the required pressure is set, the relationship between the inner diameter D and the length L of the pipe P to be processed in which the pipe inner surface blasting apparatus 1 according to the present embodiment is effective is determined. For example, if the inner diameter D of the pipe to be processed P is determined to be a constant value, the preferred shortest length L of the pipe to be processed P is determined, and if the length L of the pipe to be processed P is determined to be a constant value, the preferred maximum of the pipe to be processed P is determined. The inner diameter D is determined.

By transforming the equation (2),
L / D = 2P / (0.02 × γ × V ² ) (3)
In the formula (3), for example,
P = 70 kPa = 70000 Pa
V = 80m / s
γ = 1.2 kg / m ³ (under 20 ° C atmospheric pressure)
Then,
L / D ≒ 911.46 (4)
Here, if D = 0.08 (m), L≈72.92 (m)

Therefore, when the inner diameter D of the pipe to be processed P is 0.08 m, if the length L of the pipe to be processed P is 72.92 m or more, the conventional negative pressure suction type pipe inner surface blasting device cannot perform the blasting process. However, the blasting device 1 on the pipe inner surface according to the present embodiment can perform the blasting process.

In the above equation (4),
When L = 50 (m), D≈0.055 (m).
Therefore, when the length L of the pipe to be processed P is 50 m, if the inner diameter D of the pipe to be processed P is 0.055 m or less, the conventional negative pressure suction type pipe inner surface blasting apparatus cannot perform the polishing process. The blasting device for the pipe inner surface according to the present embodiment can perform the blasting process.

According to the blast device 1 for the pipe inner surface according to the present embodiment, air in the pipe is sucked from the downstream end P1 of the pipe P to be processed by the suction device 7 and the upstream end P2 of the pipe P to be processed by the injection device 3. Then the abrasive and air are pumped into the tube in a sealed state. As a result, a strong force for causing the abrasive and air to flow from upstream to downstream in the pipe acts simultaneously from both ends of the pipe P to be processed. For this reason, when the inner diameter D of the pipe to be processed P is small, or when the total length L of the pipe to be processed P is long, the conveying action of the polishing material is shortened over the entire length of the pipe to be processed P only by the negative pressure suction action. Even if it is difficult to exert in time, the abrasive is reliably conveyed over the entire length of the tube to be processed. As a result, regardless of the size of the tube to be processed, the blasting effect can be exerted efficiently over the entire length of the tube to be processed P.

Next, the detail of the said injection apparatus 3 is demonstrated. As shown in FIG. 2, the server tank 4 includes a hopper 13 at the top. Abrasive material is introduced into the server tank 4 through the hopper 13. A polishing material outflow pipe 14 is disposed on the lower surface of the server tank 4 downward. The scouring material outflow pipe 14 communicates with the mixing unit 5 disposed below through a metering valve 15. Therefore, the abrasive in the server tank 4 falls to the mixing section through the abrasive outlet pipe 14 and the metering valve 15. Then, by turning the operation cock 16 of the metering valve 15, it is possible to adjust the amount of the abrasive material dropped onto the mixing portion 5.

The mixing unit 5 is supplied with compressed air from the pressure feeding device 6. For this reason, if no measures are taken, the polishing material is prevented from dropping from the server tank 4 to the mixing section 5. Therefore, the compressed air from the pressure feeding device 6 is also introduced into the server tank 4 and a pressure sensor 17 for detecting the internal pressure of the mixing unit 5 is provided. The pressure sensor 17 receives a detection signal to equal the internal pressure of the mixing unit 5. A regulator 18 for controlling the internal pressure of the server tank 4 is provided so as to be more than that. As a result, the internal pressure of the server tank 4 can be controlled to be equal to or higher than the internal pressure of the mixing unit 5, and a smooth drop of the abrasive from the server tank 4 to the mixing unit 5 can be realized.

The compressed air from the pressure feeding device 6 is pressure fed to the header tank 20 through the air dryer 19. The header tank 20 communicates with the mixing unit 5 via the main air pipe 21. An air valve 22 is disposed on the main air pipe 21. Further, the header tank 20 communicates with the server tank 4 via the sub air pipe 23. On the sub air pipe 23, the regulator (electro-pneumatic regulator) 18 and the residual pressure exhaust valve 24 are disposed in this order from the header tank 20 side. The sub air pipe 23 enters the server tank 4 in an airtight state, and opens upward at an upper central position in the server tank 4. A sealing control valve 26 made of an umbrella-shaped valve body is fitted in the upward opening 25 so as to be movable up and down. The sealing control valve 26 seals the lower end opening 27 of the hopper 13 at the raised position and opens the lower end opening 27 of the hopper 13 at the lowered position. When air is pumped from the header tank 20 into the server tank 4 through the sub air pipe 23, the air pushes up the sealing control valve 26 to the raised position, and the lower end opening 27 of the hopper 13 is closed in an airtight manner. As a result, the server tank 4 is hermetically sealed except for the portion of the scouring material outflow pipe 14.

Further, the internal pressure of the server tank 4 increases due to the air pressure fed into the server tank 4 through the sub air pipe 23. The internal pressure of the server tank 4 is controlled by the electropneumatic regulator 18 to be equal to or higher than the internal pressure of the mixing unit 5. Excess compressed air is naturally exhausted from the residual pressure exhaust valve 24.

The mixing unit 5 communicates with the cyclone pipe 28. At the downstream end of the cyclone pipe 28, a connection portion 29 to the processing pipe P is formed. The connecting portion 29 has a shape that expands toward the tip so that it can accommodate various outer diameter sizes of the pipe P to be processed. The compressed air supplied to the mixing unit 5 through the main air pipe 21 is swirled around the center axis X of the cyclone pipe 28 while containing the abrasive material supplied to the mixing unit 5. To the downstream side at high speed. This swirling flow A is the abrasive material conveying airflow.

In the present embodiment, the mixing portion 5 is connected to the cyclone pipe 28 in an eccentric state so that a swirl flow A is generated in the cyclone pipe 28 having a circular cross section. However, the means for forming the swirling flow is not limited to this, and a rotating blade or a guide for swirling the compressed air can be provided. By pumping the cleaning material transport air flow into the processing pipe P while swirling, the polishing material easily collides with the inner surface of the processing pipe P. For this reason, the entire inner surface of the pipe P to be processed can be effectively polished.

In the present embodiment, all of the compressed air supplied from the pumping device 6 to the mixing unit 5 is pumped into the processing pipe P in a sealed state. In addition, a negative pressure suction force acts in the pipe P to be processed by the suction device 7 from the downstream end P1 side of the pipe P to be processed. For this reason, the inner diameter is small or the total length is not long enough to draw the polishing material conveying air flow from the upstream end P2 of the processed pipe P only by the negative pressure suction force of the suction device 7. However, it is possible to flow the blast material conveying airflow at a high speed of 80 m / s or higher, and to efficiently perform the blasting process. The in-pipe flow velocity of the abrasive transporting airflow is preferably, for example, 100 m / s or more, and more preferably 120 m / s or more.

In the present embodiment, since the abrasive and air are jetted from the injection device 3 into the treated pipe P in a sealed state, the amount of inflow of the abrasive conveying air flow into the treated pipe P is reduced. If it is larger than the outflow amount of the abrasive conveying airflow from the processing pipe P, it will lead to damage of the apparatus. For this reason, it sets so that the suction | inhalation amount of the scouring material conveyance airflow by the suction device 7 may become larger than the pumping amount of the scouring material conveyance airflow by the injection apparatus 3. FIG.

In the present embodiment, as the simplest example, a description has been given of a single server tank 4 provided with one system of the mixing unit 5 and the cyclone pipe 28, but another example for increasing the processing efficiency. It is also possible to provide a plurality of mixing sections 5 and cyclone pipes 28 for a single server tank 4. In the case where a plurality of systems of the mixing unit 5 and the cyclone pipe 28 are provided, it is particularly effective to provide the header tank 20 as an accumulator for stably supplying air to each system.

Next, a pipe inner surface blasting system including the aforementioned pipe inner surface blasting device 1 will be described with reference to FIG. This system is intended to solve the problem that there is a difference in the effect of the blasting process on the inner surface of the pipe P1 between the both ends P1, P2. That is, the swirling flow A of the abrasive flowing in the processing pipe P becomes weaker as it approaches the downstream end P1 even if the degree of swirl is strong on the upstream end P2 side. For this reason, there exists a problem that the scouring effect in the downstream end P1 side of the to-be-processed pipe P falls.

In order to solve this problem, the pipe inner surface blasting system 30 of the present embodiment includes two blasting apparatuses having the same configuration as the blasting apparatus 1. These blasting devices (the entry blasting device 1a and the exiting blasting device 1b) are arranged so as to act in opposite directions on the entry side and the exit side along the transfer line of the pipe P to be processed.

As shown in FIG. 3, the entry-side blast device 1a and the exit-side blast device 1b are disposed between the entry-side facility 31a and the exit-side facility 31b. The entrance-side facility 1a and the exit-side facility 1b are connected to each other by a transfer conveyor 32 serving as a transfer line for the pipe P to be processed. An entrance blast device 1a is disposed on the entry side along the transfer conveyor, and an exit blast device 1b is disposed on the exit side.

The inlet-side blast device 1a includes an inlet-side suction device 7a that sucks air in the pipe from one end Pa of the pipe P to be processed, and a polishing material and air from the other end Pb of the pipe P to be sealed in the pipe. And an inlet-side injection device 3a that injects as a swirling flow. On the other hand, the outlet blast device 1b includes an outlet suction device 7b that sucks air in the pipe from the other end Pb of the pipe to be processed P, and a polishing material and air in a sealed state from one end Pa of the pipe to be processed P. And an exit-side injection device 3b that injects as a swirling flow. The inlet suction device 7a and the outlet suction device 7b have the same configuration as the suction device 7 described above. Similarly, the inlet side injection device 3a and the outlet side injection device 3b have the same configuration as the injection device 3 described above.

According to the system 30 of the present embodiment, the pipe to be processed P is supplied from the entrance side equipment 31a to the entrance side blast apparatus 1a by the transfer conveyor 32, and is subjected to a polishing process by the entrance side blast apparatus 1a. Thereafter, the pipe P to be processed is transferred to the delivery side blasting apparatus 1b by the transfer conveyor 32, and subjected to the blasting process again by the delivery side blasting apparatus 1b. The pipe P to be processed after the blasting process is sent out to the delivery facility 31b by the transfer conveyor 32.

In the inlet-side blast device 1a, air in the pipe is sucked from the one end Pa of the pipe to be processed P by the inlet-side suction apparatus 7a, and the inside of the pipe is sealed from the other end Pb of the pipe to be processed P by the inlet-side injection device 3a. The cleaning material and air are jetted as a swirl flow A. As a result, a strong force for causing the abrasive and air to flow in the pipe from the other end Pb of the pipe to be processed P toward the one end Pa is simultaneously applied from both ends of the pipe to be processed P. For this reason, even when the inner diameter of the pipe to be processed P is small and the total length is long, even if it is difficult to exert the conveying action of the scouring material over the entire length of the pipe to be processed P only by the negative pressure suction action. The polishing material is reliably conveyed over the entire length of the pipe P to be processed.

In the outlet blast device 1b, air in the pipe is sucked from the other end Pb of the pipe to be processed P by the outlet suction apparatus 7b, and the inside of the pipe is sealed from the one end Pa of the pipe to be processed P by the outlet jetting apparatus 3b. The cleaning material and air are jetted as a swirl flow A. As a result, a strong force for causing the abrasive and air to flow in the pipe from one end Pa to the other end Pb of the pipe to be processed P acts simultaneously from both ends of the pipe to be processed P. For this reason, even when the inner diameter of the pipe to be processed P is small and the total length is long, even if it is difficult to exert the conveying action of the scouring material over the entire length of the pipe to be processed P only by the negative pressure suction action. The polishing material is reliably conveyed over the entire length of the pipe P to be processed.

In the present embodiment, the single pipe P is subjected to the blasting process twice by reversing the action directions of suction and jetting (the flow direction A of the scouring material). Thereby, it becomes possible to equalize the effect of the blasting process by the swirling flow A between both ends of the pipe P to be processed. In addition, since the inlet blast device 1a and the outlet blast device 1b are arranged on the inlet side and the outlet side along the transfer line 32 of the pipe to be processed P, the pipe to be processed P is subjected to the blasting process twice. There is no need to invert. Therefore, work can be performed easily and processing efficiency is good.

Further, in the example of FIG. 3, the inlet blast device 1a is positioned on the other end Pb side of the pipe P to be processed, and stores the abrasive for feeding into the pipe, and the pipe to be processed. An inlet-side receiver tank 9a that is located on the one end Pa side of P and that receives the polishing material that has passed through the pipe P to be processed. In addition, the outlet blasting device 1b is located on the one end Pa side of the pipe to be processed P, and stores an outlet server tank 4b for storing a polishing material to be supplied into the pipe to be processed P. And a delivery-side receiver tank 9b that receives the scouring material that is located on the end Pb side and that has passed through the processing pipe P. The incoming receiver tank 9a and the outgoing server tank 4b are connected by the abrasive transfer path 33 so that the abrasive in the incoming receiver tank 9a can be transferred into the outgoing server tank 4b. Similarly, the outlet-side receiver tank 9b and the inlet-side server tank 4a are connected by a polishing material transfer path 34 so that the abrasive in the outlet-side receiver tank 9b can be transferred into the inlet-side server tank 4a.

According to this configuration, the polishing material that has finished the inner surface of the processing pipe P by the inlet blast device 1a is reintroduced into the outlet blast device 1b, and similarly, the processing pipe is processed by the outlet blast device 1b. The polishing material that has finished the polishing of the inner surface of P is reintroduced into the entry-side blast device 1a, and this is repeated. Since the abrasive is used to circulate repeatedly, it is economical.

Further, the incoming receiver tank 9a constituting the incoming blasting device 1a and the outgoing server tank 4b constituting the outgoing blasting device 1b are both on the one end Pa side of the processing pipe P. Further, the outlet receiver tank 9b constituting the outlet blasting device 1b and the inlet server tank 4a constituting the inlet blasting device 1a are both on the other end Pb side of the pipe P to be processed. For this reason, the scouring material transfer path 33 between the inlet-side receiver tank 9a and the outlet-side server tank 4b and the scouring material transfer path 34 between the outlet-side receiver tank 9b and the inlet-side server tank 4a are: Both can be short, and the arrangement layout of the abrasive transfer paths 33 and 34 can be simplified. Therefore, the arrangement cost of the scouring material transfer paths 33 and 34 can be saved, which is more economical.

DESCRIPTION OF SYMBOLS 1 Pipe blasting device 1a Inlet side blasting device 1b Outlet side blasting device 3 Injection device 3a Inlet side injection device 3b Outlet side injection device 4 Server tank 4a Inlet side server tank 4b Outlet side server tank 5 Mixing part 6 Pumping device 7 Suction Device 7a Inlet side suction device 7b Outlet side suction device 9a Inlet side receiver tank 9b Outlet side receiver tank 18 Regulator P Pipe to be treated P1 Downstream end of pipe to be treated P2 Upstream end of pipe to be treated Pa One end of pipe to be treated Pb The other end of the tube

Claims (7)

A method for blasting an inner surface of a pipe, wherein air in the pipe is sucked from the downstream end of the pipe to be processed, and the abrasive and air are pumped into the pipe in a sealed state from the upstream end of the pipe to be processed. The pipe to be treated that is a straight pipe substitutes a specific numerical value for P, γ, V (80 m / s or more) and substitutes a specific numerical value for either L or D in the following equation. The method for blasting a tube inner surface according to claim 1, wherein the blasting method is a size of not more than D or not less than L obtained by.
L / D = 2P / (0.02 × γ × V ² )
L: Length of pipe to be processed m
D: Inner diameter (diameter) of the pipe to be processed
P: Required pressure Pa
γ: air density kg / m ³
V: Flow velocity in the pipe to be processed m / s A suction device that sucks air in the pipe from the downstream end of the pipe to be processed, and an injection device that jets the polishing material and air into the pipe in a sealed state from the upstream end of the pipe to be processed. Blasting device. For the size of the pipe to be processed, which is a straight pipe, substitute specific numerical values for P, γ, V (80 m / s or more) and substitute specific numerical values for either L or D in the following formula. The blasting device for an inner surface of a pipe according to claim 3, wherein the blasting apparatus has a size of D or less or L or more obtained by performing the process.
L / D = 2P / (0.02 × γ × V ² )
L: Length of pipe to be processed m
D: Inner diameter (diameter) of the pipe to be processed
P: Required pressure Pa
γ: air density kg / m ³
V: Flow velocity in the pipe to be processed m / s The spraying device mixes the scouring material and the air upstream of the upstream end of the pipe to be processed, stores the scouring material, and supplies the scouring material to the mixing unit. A sealed server tank, a pumping device for pumping air into the mixing unit and the server tank, and a regulator for controlling the internal pressure of the server tank so as to be equal to or higher than the internal pressure of the mixing unit A blasting device for a pipe inner surface according to claim 3 or 4. A blasting device is provided on each of the inlet side and the outlet side along the transfer line of the pipe to be processed. The inlet blasting apparatus includes an inlet side suction device that sucks air in the pipe from one end of the pipe to be processed, and a grinding device. An inlet-side injection device that injects scavenging material and air as a swirling flow into the tube in a sealed state from the other end of the tube to be processed, and the outlet blast device is connected to the other end of the tube to be processed. A pipe inner surface blasting device comprising: an outlet side suction device that sucks air in the pipe; and an outlet side injection device that jets the abrasive and air as a swirling flow into the pipe in a sealed state from the one end of the treated pipe. system. The entry side blasting device is located on the other end side of the pipe to be treated and stores an inlet side server tank for storing an abrasive to be supplied into the pipe to be treated, and on the one end side of the pipe to be treated. An inlet-side receiver tank that receives the polishing material that is positioned and passes through the processing pipe, and the outlet-side blasting device is positioned on the one end side of the processing pipe and is supplied into the processing pipe An exit side server tank for storing the abrasive for cleaning, and an exit side receiver tank that is located on the other end side of the pipe to be processed and that receives the abrasive that has passed through the pipe to be processed. The inlet receiver tank and the outlet server tank are connected so that the abrasive in the receiver receiver tank can be transferred into the outlet server tank, and the abrasive in the outlet receiver tank is inserted into the inlet receiver tank. Transfer to the server tank And the exit-side receiver tank and entering-side server tank is connected to hang, inner surface blasting system according to claim 6.

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