JPS5944918B2 - Pipe inner surface cleaning device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cleaning device used for cleaning the inner surface of a pipe.

U-shaped tubes are widely used in heat exchangers, chemical pipelines, etc., but it is extremely difficult to polish the inner surface of the tube by a physical method to remove coating or deposits on the inner surface of the tube.

Therefore, in the past, chemical treatment agents were exclusively used to polish the inner surface of the U-shaped tube.

As shown in FIG.
and an injection nozzle 5, and a device for polishing the inner surface of the pipe by swirling compressed air containing abrasive particles and forcefully feeding it from the nozzle 5 into a straight pipe T to be treated. This was proposed previously (Special Publication No. 16029/1983).

According to the above-mentioned device, since the abrasive fluid is injected from the injector nozzle while swirling, the abrasive particles do not pass through the inlet of the pipe 7 to be treated, and the advantage is that the abrasive particles can be uniformly cleaned without unevenness. Ta.

However, the compressed air flow to which rotational force is applied by the rotating plate 1 is constricted by the nozzle 5, and the moment it is ejected from the nozzle 5, the volume expands to atmospheric pressure, increasing the flow velocity by the expansion factor.

Therefore, the rotation pitch of the compressed air ends up being longer than the twisting pitch of the rotation plate 1. For example, the compressed air is 5 atm and the twisting pitch of the rotating plate 1 is 3 OCI! If it is L, the swirling pitch of the airflow ejected from the nozzle will be extended to 150 cwL, and the swirling effect will be low. If the pipe T to be treated is straight,
There is no problem even if the swirling pitch of the compressed air flow containing the abrasive particles is extended. However, when the above method is applied to polishing a pipe that is bent in the middle, such as the U-shaped pipe shown in Figure 1, the abrasive particles are concentrated on the surface TO, which has a smaller curvature on the inner surface of the bent part. There was a problem that the collision caused a deep cut on the surface, and if it was a thin-walled pipe, it would break.

On the other hand, since the amount of abrasive grains passing through the surface 71 of the inner surface of the bent portion with a larger curvature increases, the polishing becomes incomplete.
It was not possible to treat the inner surface of a bent pipe using a rotating nozzle.

An object of the present invention is to properly abrade not only a straight pipe but also the inner surface of a curved pipe by injecting the abrasive particles onto the pipe to be treated while rotating them at a short pitch.

The present invention includes a rotating plate 1 in a mouthpiece 2 connected to one end of a pipe 7 to be treated, and by disposing an abrasive particle injection nozzle 5 on the upstream side of the rotating plate 1, the abrasive particles from the injection nozzle 5 are removed. Converts the pressurized air flow containing particles into a swirling flow with a short swirling pitch, thereby causing the abrasive particles to pass through the pipe to be processed while swirling, that is, suppressing the straight speed component of the abrasive airflow to a small value. By doing so, not only straight pipes but also curved pipes can be polished with just the right amount, regardless of whether the inner surface of the bent portion has a larger or smaller curvature.

The present invention will be specifically described below based on embodiments shown in the drawings. Although Fig. 1 shows a state in which the pipe to be treated 7 bent in a U-shape can be polished, the present invention is not limited to this, and various types of pipes such as straight pipes and pipes bent at 90 degrees can be cleaned. It is.

One end of the pipe to be processed 7 is removably connected to the abrasive grain supply pipe 6 via the mouthpiece 2, and the other end to the abrasive grain collection casing 8.

The cap 2 is made up of two long and short receiving tubes 3 and 4 connected on the same straight line, and has an injection nozzle 5 between the long receiving tube 3 and the short receiving tube 4.

The injection nozzle 5 has a threaded portion 51 at its base end screwed into the tip of the inner hole of the short receiving tube 4, and the nozzle portion at the tip protrudes into the long receiving tube 3.

Stepped support surfaces 31 and 41 are formed around both ends of the inner hole of the mouthpiece 2 to connect the pipe to be treated 7 and the abrasive grain supply pipe 6, and the support surfaces 31 and 41 are provided with stepped support surfaces 31 and 41 for connecting the pipe to be treated 7 and the abrasive grain supply pipe 6, respectively. Packings 32 and 42 that serve as contact surfaces for the pipe 6 and the pipe to be treated 7 are fitted.

A rotating plate 1, which is a feature of the present invention, is press-fitted into the long receiving tube 3 between the tip of the nozzle 5 and the support surface 31.

The rotating plate 1 is made of a material with excellent wear resistance such as cemented carbide, and has the shape of a belt-shaped plate twisted about two times, and has a total length of about 30 mm.
It is C.

One end of the pipe to be treated 7 is fitted into the elongated receiving tube 3 of the mouthpiece 2, and the other end is communicated with the abrasive particle collection box 8.

The abrasive grain feed pipe 6 is connected to the short receiving pipe 4 of the mouthpiece 2.

In the above state, when compressed air containing abrasive particles is fed from the feed pipe 6 into the nozzle 2, the compressed air is throttled by the nozzle 5 and the air and the abrasive particles are stirred and mixed.

As soon as the abrasive airflow is ejected from the nozzle 5, the mouthpiece 2 is open to atmospheric pressure, so the airflow rapidly expands and increases the flow velocity. is converted into rotational energy of the airflow, resulting in a rotating airflow that rapidly rotates with a turning pitch approximately equal to the torsional pitch (about 15 cm) of the turning plate, and the straight energy is considerably reduced.

In a U-shaped tube, there is almost no airflow component that travels straight through the center of the tube, and the cleaning airflow is concentrated on the inner peripheral surface of the pipe due to centrifugal force and flows along the inner surface of the pipe by swirling.

Even in the curved part 7a of the pipe to be treated, the abrasive grains do not concentrate and collide with the outer circumference side surface 70 as in the conventional case, and instead of colliding with either the outer circumference side surface 70 or the inner circumference side surface 71. This means that the parts can be polished evenly just like any other straight surface. Furthermore, a conventional rotating plate 1 is also installed in the pipe between the feed pipe 6 and the injection nozzle 5.
If this is installed, a swirling flow of compressed air is injected from the nozzle 5, and this hits the swirling plate 1 on the downstream side of the nozzle and is forcibly rotated again, so a strong swirling flow is generated. The cleaning effect can be further enhanced.

Furthermore, the flow velocity of the abrasive particles can be increased by providing compressed air pipe 9 obliquely in the base 2 and supplying compressed air as shown by the two-dot chain line in FIG.

The compressed air pipe 9 is installed with the outlet 91 inclined toward the tip of the nozzle 5 in the base 2 and facing the direction of connection of the base 2 so as not to go against the direction of rotation of the compressed air containing the abrasive particles. Therefore, the flow velocity of the abrasive particles passing through the rotating plate 1 is increased by the compressed air, and the cleaning effect is improved. FIG. 2 shows another embodiment in which the tip of the base 2 is bent at 90 degrees, and in this case, there is an advantage that a large space is not required when cleaning the U-shaped pipe 7.

As described above, the present invention provides a rotating plate 1 on the outlet side of the injection nozzle 5.
By deploying this, the high-speed abrasive airflow ejected from the nozzle and expanding to atmospheric pressure converts the expansion force into rotational energy by the rotating plate 1, and the straight velocity component can be suppressed to a small value, so that the abrasive particles are The rotating pitch of the rotating plate is almost maintained, and even if the pipe passes through the pipe 7 to be treated and is bent in the middle, the centrifugal force caused by the swirling of the compressed air will cause the inner and outer periphery of the pipe to bend. It has an excellent effect in that the side surface can be polished uniformly and without excess or deficiency like other straight parts.

It goes without saying that the present invention is not limited to the above configuration, and that various modifications can be made within the technical scope of the claims.

[Brief explanation of drawings]

Figure 1 is a sectional view of the device, Figure 2 is a front view of another embodiment,
FIG. 3 is a cross-sectional view of the conventional door 11. As shown in FIG. 1... Swivel plate, 2... Base, 5...
...Injection nozzle.

Claims (1)

[Claims] 1 A rotating plate 1 having a short pitch twist immediately after the outlet of the injection nozzle 5 communicating with the compressed air and abrasive granule feed pipe 6
A pipe inner surface polishing device characterized in that it is equipped with a mouthpiece 2 equipped with.