Spray unit with a rotatable nozzle as well as a blasting device

Abstract

A blasting device has a spray unit for spraying blasting agent onto the surface to be treated. The spray unit has an insert 23′ in which a nozzle 13′ is rotatable. This nozzle 13′ is provided with a number of spray channels 19′ which are at an angle 21′ relative to the supply direction 17 of the blasting agent. The blasting agent is pressed through the spray channels 19′ under pressure and exerts a force on the wall of the spray channels 19′ causing the nozzle 13′ to rotate. The jets emerging from the rotating nozzle 13′ will make a rotating movement. The joint area of the cross-sections of the spray channels 19′ is larger than one third of the cross-sectional area of the circular-cylindrical part of the nozzle. The angle 21′ at which the spray channels are located with respect to the supply direction 17 of the blasting agent is greater than zero and less than 10 degrees.

Claims

1. Spray unit for use in a blasting device for treating a surface, by spraying blasting agent under pressure on the surface to be treated, which spray unit is provided with a housing, as well as a nozzle being rotatably in the housing about an imaginary axis parallel to the supply direction of the blasting agent, and being provided with a number of spray channels that are angled with respect to the direction of feed of the blasting agent, the main part of the nozzle having a circular-cylindrical shape, and the nozzle being provided with an entry side where the blasting agent enters the spray channels and an exit side where the blasting agent leaves the spray channels, wherein the joint area of the cross-sections of the spray channels at right angles to the imaginary axis at the exit side is greater than one third of the area of the cross-section of the circular-cylindrical part of the nozzle perpendicular to the imaginary axis.

2. Spray unit according to claim 1, wherein the angle at which the spray channels are located with respect to the supply direction of the blasting agent is greater than zero and less than 10 degrees.

3. Spray unit according to claim 1, wherein the nozzle is further provided with a further spraying channel which is present in the center of the nozzle and is parallel to the blasting agent supply direction.

4. Spray unit according to claim 1, wherein the spray unit is further provided with an insert which is fixed in the housing, the nozzle being rotatable in the insert.

5. Spray unit according to claim 4, wherein the nozzle is provided with two axial end faces and a lateral surface extending there between, and that the insert is provided with a through hole in which the nozzle is rotatable, which hole is delimited by an inner side of the insert, whereby there is play between the mantle surface of the nozzle and the inside of the insert.

6. Spray unit according to claim 5, wherein the inner side of the insert is provided with recesses which are distributed over the circumference at a mutual distance from each other and which extend over the entire thickness of the nozzle.

7. Blasting device provided with a spray unit according to claim 1, for treating a surface by spraying blasting agent under pressure on the surface to be treated, comprising: a container for the blasting agent, a blasting agent line through which the spray unit is connected to the container, and a supply unit for supplying the blasting agent from the container to the spray unit, which supply unit is connected to the blasting agent line between the container and the spray unit.

8. Blasting device according to claim 7, wherein the supply unit is provided with a water connection to which a water pipe can be connected and the supply unit comprises a mixing unit for mixing the blasting agent with water.

9. Blasting device according to claim 7, wherein the supply unit is provided with a compressed air connection to which a compressed air line can be connected, which supplies the mixture of blasting agent and water to the spray unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The invention will be explained in more detail below with reference to exemplary embodiments of the blasting device and the spray unit shown in the drawings. In the drawings:

[0021] FIG. 1 is a schematic representation of an embodiment of the blasting device according to the invention which is suitable for wet blasting;

[0022] FIG. 2 is an embodiment of the blasting device according to the invention which is suitable for dry blasting;

[0023] FIG. 3 is an example of a spray unit for a blasting device in perspective;

[0024] FIG. 4 is the spray unit shown in FIG. 3 in side view;

[0025] FIG. 5 is an example of an insert with a nozzle therein in cross section;

[0026] FIG. 6 is the insert shown in FIG. 5 with the nozzle therein in top view;

[0027] FIG. 7 is the insert shown in FIG. 5 in cross section;

[0028] FIG. 8 is a side view of the nozzle shown in FIG. 5;

[0029] FIG. 9 is an embodiment of the insert with therein the nozzle of the spray unit according to the invention in cross section;

[0030] FIG. 10 is the insert with nozzle shown in FIG. 9 in top view;

[0031] FIG. 11 is the insert shown in FIG. 9 in cross section; and

[0032] FIG. 12 is the nozzle shown in FIG. 9 in side view.

DETAILED DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 is a schematic representation of an embodiment of the blasting device according to the invention which is suitable for wet blasting. The blasting device 1 has a container 3 in which blasting agent 2 is present. The blasting agent 2 is formed by fine-grained material mixed with water. The fine-grained material is, for example, ceramic grains or glass beads. The blasting device 1 further has a spray unit 5 for spraying the blasting agent under pressure onto a surface to be treated. This spray unit 5 is connected to the container 3 via a blasting agent line 7. A supply unit 9 accommodated in the blasting agent line 7 between the container and the spray unit ensures the supply of the blasting agent 2 from the container 3 to the spray unit 5.

[0034] The supply unit 9 has a mixing unit 27 for mixing the blasting agent 2 with water and is provided for this purpose with a water connection 29 to which a water pipe 31 is connected. This water pipe 31 is also connected to the container 3, so that a control can ensure that a correct ratio of solid particles and liquid is present in the container to prevent the solid particles from forming a compact mass, so that they no longer flow via the blasting agent line 7 but could flow via the mixing unit 27. The supply unit 9 further has a compressed air connection 33 to which a compressed air line 35 is connected which supplies the mixture of blasting agent and water to the spray unit 5.

[0035] FIG. 2 shows another embodiment of the blasting device 1 according to the invention. This embodiment is suitable for dry blasting. In that case the blasting agent only has dry fine-grained material such as ceramic grains or glass pearls. In this case the mixing unit 27′ is also present near the outflow opening of the container 3′, but the blasting agent is entrained by air from compressed air line 35′ and fed to the spray unit 5 via the blasting agent line 7′.

[0036] In FIGS. 3 and 4, the spray unit 5, which is suitable for both wet blasting (FIG. 1) and dry blasting (FIG. 2), is shown in perspective and side view, respectively. The spray unit 5 has a housing 11 with a nozzle 13 rotatably present therein. During spraying, the nozzle rotates about an imaginary axis 15 parallel to the supply direction 17 of the blasting agent. A guide 18 is provided on the housing 11 which guides the jets of the blasting agent exiting the nozzle and bends it in a desired direction. The nozzle 13 is rotatable in an insert 23 which is clamped in the housing 11 by means of the guide 18 screwed into the housing 11.

[0037] FIGS. 5 and 6 show an example of the insert 23 with the nozzle 13 therein in cross-section and top view, respectively. The nozzle 13 is provided with two axial end faces 13a, 13b and a lateral surface 13c extending there between. The insert 23 is provided with a through hole 24 in which the nozzle 13 is rotatably present. The cylindrical mantle surface 13c of the nozzle 13 slides along the cylindrical inner wall 23a of the insert 23 during spraying. To limit friction and wear, the insert is preferably of Teflon or another suitable material and the nozzle is preferably of hardened steel or other hard metal.

[0038] The nozzle 13 is provided with a protruding ridge 13B which, in the direction of feed 17 of the blasting agent, is rotatably enclosed between an edge 23b of the insert 23 and a retaining ring 26.

[0039] In order to prevent the nozzle 13 from jamming in the insert 23 during use, play is present between the mantle surface 13c of the nozzle and the inside 23a of the insert. For this purpose, the inner side 23a of the insert 23 is further provided with recesses 25 which are distributed over the circumference at a mutual distance from each other. These recesses extend over the entire thickness of the insert 23 and in this embodiment have a semi-circular cross-section.

[0040] In FIGS. 7 and 8 the insert 23 and the nozzle 13 are shown separately in section and bottom view, respectively. The nozzle 13 is provided with a number of spray channels 19 which are at an angle 21 with respect to the supply device 17 of the blasting agent. The blasting agent is pressed through the spray channels 19 under pressure and exerts a force on the wall of the spray channels 19, causing the nozzle 13 to rotate. Since the insert 23 is secured against rotation by the guide 18, the nozzle 13 in the insert 23 will start to rotate. The jets emerging from the rotating nozzle 13 will also make a rotating movement, so that a better jet effect is obtained.

[0041] In order to be able to properly remove stubborn dirt and irregularities, the nozzle 13 is also provided with a further spray channel 20 which is present in the center of the nozzle. This further spray channel 20 extends parallel to the delivery device of the blasting agent.

[0042] In FIGS. 9 and 10 an embodiment of the insert 23′ with the nozzle 13′ of the spray unit according to the invention therein is shown in cross-section and top view, respectively. In FIG. 11 the insert 23′ is shown separately in cross-section and in FIG. 12 the nozzle 13′ is shown separately in side view. The nozzle 13′ is provided with two axial end faces 13a′, 13b′ and a lateral surface 13c′ extending there between. The insert 23′ is provided with a through hole 24′ in which the nozzle 13′ is rotatable. The nozzle 13′ is provided with a protruding ridge 13B′ which, in the feed direction 17 of the blasting agent, is rotatably enclosed between an edge 23b′ of the insert 23′ and a retaining ring 26.

[0043] In order to prevent the nozzle 13′ from jamming in the insert 23′ during use, there is play between the mantle surface 13c of the nozzle and the inside 23a of the insert, and the inside 23a′ of the insert 23′ is provided with recesses 25′ that are distributed over the circumference at a mutual distance from each other. These recesses extend over the entire thickness of the insert 23′ and in this embodiment have a semi-circular cross-section.

[0044] The nozzle 13′ is provided with a number of nozzles 19′ which are at an angle 21′ relative to the feed device 17 of the blasting agent. The blasting agent is pressed through the nozzles 19′ under pressure and exerts a force on the wall of the nozzles 19′, causing the nozzle 13′ to rotate. The jets emerging from the rotating nozzle 13′ will also make a rotating movement, resulting in a better jet effect. Good results are obtained with a nozzle in which the nozzles 19′ at an angle 21′ of 1 to 7 degrees are present. In the embodiment shown, the nozzles 19′ are present at an angle 21′ of 5 degrees.

[0045] Although the present invention is elucidated above on the basis of the given drawings, it should be noted that this invention is not limited whatsoever to the embodiments shown in the drawings. The invention also extends to all embodiments deviating from the embodiments shown in the drawings within the scope of the invention defined by the appended claims.