JPH0152152B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a sandblasting nozzle.

(Prior art and its problems) When sandblasting is used to sandblast the inner surface of a pipe that is curved into an L-shape or a U-shape, the curved part of the pipe is locally carved out by the abrasive material. , the wall thickness became thinner, and in extreme cases there was a problem of the tube breaking.

The applicant proposed that the abrasive material be injected into the pipe in a swirling flow so that the abrasive material collides with the inner surface of the curved pipe at a shallow angle to prevent local tearing (Unexamined Japanese Patent Publication No. (Sho 58-40184).

However, in the above case, since the blast airflow is changed into a swirling flow by the torsion plate disposed downstream of the nozzle, the torsion plate is subject to severe wear and must be replaced frequently.

It is also possible to form the torsion plate from highly wear-resistant materials such as tungsten or ceramics, but these highly wear-resistant materials have problems with workability and are not suitable for manufacturing the torsion plate.

(Means for Solving the Problems) In view of the above, the present invention discloses a sandblasting nozzle that can solve the above problems by devising the tip of the nozzle.

The present invention forms a reservoir chamber 3 on the inflow side of the blast air flow of the nozzle holder 1, and a plurality of small diameter nozzles 5 formed of a hard material on the wall 4 on the outlet side of the holder 1 that closes the reservoir chamber 3, and the nozzle. 5 are attached with their tips tilted in the same direction, and the base end of each small diameter nozzle 5 is opened into the reservoir chamber 3, and the tip is opened toward the front of the nozzle holder.

(Function and Effect) Since the small diameter nozzles are inclined in the tangential direction of the nozzle holder, the blast airflow ejected from the 5 groups of small diameter nozzles becomes a spiral flow in the pipe to be polished and is ejected while expanding. The blast flow is shallow even at the curved part of the pipe (almost parallel to the inner surface of the pipe).
Because of this, there is no risk of locally deeply carving out the bent portion of the pipe, unlike in the conventional case.

Furthermore, according to the present invention, the high-speed abrasive airflow that is ejected from the nozzle and is expanding to atmospheric pressure converts the expansion force into rotational energy, and as a result, the velocity component that travels straight can be suppressed to a small value, so that the turning pitch can be suppressed. The compressed air passes through the tube to be polished and is maintained almost constant, and evenly coats the inner and outer surfaces of the curved portion of the tube due to the centrifugal force caused by the swirling of the compressed air. It has an excellent effect of cleaning without any problems.

(Embodiment) FIG. 1 shows an embodiment of the present invention, in which a nozzle holder 1 is fitted with a large diameter nozzle pipe 2 made of a hard material on the inflow side of the blast air flow, and the front of the nozzle pipe 2 is A reservoir chamber 3 with an enlarged inner diameter is formed between the front wall and the front wall.

Three through holes 6 are formed at equal intervals in the front wall 4, parallel to the nozzle axis and inclined in the tangential direction of the nozzle holder 1, and the small diameter nozzles 5 shown in FIG. 3 are inserted into the three through holes 6, respectively. The front wall 4 and each small diameter nozzle 5 are fitted and held down with screws 7 screwed onto the nozzle holder 1, and a press plate 8 is placed on the opening of the nozzle holder 1 and fixed to the end face of the nozzle holder 1 with screws 9. It is held down to prevent it from falling out.

The blast airflow flowing into the inflow side of the nozzle is ejected from the nozzle pipe 2 and fills the reservoir chamber 3, forming a high-pressure air condition. 3 in storage room 3
Since the base ends of the small-diameter nozzles 5 are open, the blast airflow is divided equally and flows into each of the three small-diameter nozzles 5, and is ejected from the tip as a bundle of three narrow blast airflows.

Since each small diameter nozzle 5 is inclined in the tangential direction,
The blast air stream from the nozzle spirals inside the tube to be cleaned.

Incidentally, the small-diameter nozzle can be tilted as described above, and the tip of the small-diameter nozzle can also be tilted outward as shown in FIG. 4. Even in this case, each small diameter nozzle 5
Since the nozzle is inclined approximately tangentially, when the nozzle is inserted into the pipe to be cleaned, the blast airflow from the nozzle is ejected in a spiral manner inside the pipe.

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

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a sandblasting nozzle according to the present invention, FIG. 2 is a sectional view taken along the line - in FIG. 1, FIG. 3 is a longitudinal sectional view of a small diameter nozzle, and FIG. FIG. 3 is a cross-sectional view of the nozzle tip. 1... Nozzle holder, 2... Nozzle pipe, 3...
...Reservoir chamber, 4...Front wall, 5...Small diameter nozzle.

Claims (1)

[Scope of Claims] 1. A reservoir chamber 3 is formed on the blast air inflow side of the nozzle holder 1, and a plurality of small diameter nozzles formed of a hard material on the front wall 4 of the holder 1 outlet side that closes the reservoir chamber 3. 5 are mounted in the tangential direction of the holder and tilted in the same direction, and the base end of each small diameter nozzle 5 opens into the reservoir chamber 3, and the tip opens toward the front of the nozzle holder. The sandblasting nozzle according to claim 1, wherein the tip of the small diameter nozzle 5 is also inclined outward.