NL1018445C2 - Catapult wheel for forming particle jet, has space in communication with particle exit opening formed between pump wheel and casing - Google Patents

Abstract

The radial distance between the pump wheel and the casing (2) increases in the pump wheel rotation direction, forming a cavity in communication with the particle exit opening. The catapult wheel (1) comprises a casing with an inlet opening and an outlet opening for the particles, a pump wheel rotatably mounted in the casing for transporting the particles from the inlet opening to the outlet opening, and scoops (3) which are located outside and essentially coaxial with casing for rotating simultaneously with the pump wheel, in order to accelerate the particles and form a particle jet.

Description

BEAM WHEEL

The invention relates to a device for forming a particle beam, which device comprises: a housing with an inlet opening for supplying particles and an outlet opening; - a pump wheel rotatable in the housing for transporting the particles from the inlet opening to the outlet opening; outside the housing substantially coaxial, vanes rotatable in synchronism with the pump wheel for accelerating the particles and for forming a particle beam.

Such a device is also known as a throwing wheel, with which, for example, a particle beam is formed, which is subsequently thrown against an object. This particle beam can, for example, be used to remove lacquer layers or mill scale layers from the object.

Known devices have the disadvantage that they are subject to high wear. In particular, the rotatable wheel, the housing and the blades wear quickly. In addition, such known devices form a particle beam with a relatively large spread. In order to accurately beam an object, it is desirable to minimize this spread in the particle beam, or to adapt it to the object.

It is an object of the invention to reduce the abovementioned disadvantage of wear and to provide a throwing wheel with which a particle beam can be formed with a better definable spread than that of known devices. This object is achieved with a device according to the preamble, which is characterized in that the radial distance between the pump wheel and the (inner) housing increases in the direction of rotation of the pump wheel 101 844 2, in order to form a space, this space opening into the outlet opening.

Because the distance between the wheel and the housing increases, a kind of volute-shaped space is created. As a result, the flow of particles in the direction of rotation from the wheel to the discharge opening can increase, without this creating additional friction between the wheel and the housing. This reduces wear on the wheel.

In a preferred embodiment of the device according to the invention, the rotatable pump wheel comprises a bush, wherein holes are arranged in the peripheral wall of the bush and the inside of the bush connects to the inlet opening. Such a bus can p ^ pomrm in rr tto v'xrap -v ~ r \ ryr \ ön Ή * t f *! ο τras -η -τpp] ί τίΗί éstï -L ζΧ · Λ X V> »_ / U'uiX V OJ. V UUi. S-X U. ^ N_A. VV \ S _L_ \ JL X X · J_ / _1_ _i_ O v Gtxx V W W UCC J_ J_ iiu, ICii a worn bush must be replaced.

In another preferred embodiment of the device according to the invention, each blade is curved, the blade surface adjacent to the housing forms an obtuse angle with the tangential of the housing surface and the blade surface near the distal end of the blade forms an acute angle with the tangential of the housing surface. Due to the blunt corner, packets of the particle stream from the outlet opening are scooped up by a vane. Due to this blunt angle, the particles located between two vanes can easily spread over the vane without bouncing off as a result of the vanes rotating. Because this rebounding is reduced or even eliminated, a particle beam with a smaller spread is created. Moreover, it is also possible to use a harder material for the blades.

Preferably, a first collecting part of the vane surface adjacent the housing, seen at least in the radial direction, is substantially flat. Because of this flat zone of the vane, the scooped package I if i 8445 3 * can be evenly distributed on the vane, after which it is accelerated in the second gear part.

Finally, it is preferred that the blades are detachable. Thus, the blades 5 can be replaced easily and quickly if they show too much wear.

These and other features are further elucidated with reference to the accompanying drawings.

Figure 1 shows a perspective view of a throwing wheel according to the invention.

Figure 2 shows in perspective view and in cross-section the throwing wheel according to figure 1.

Figure 1 shows a throwing wheel 1 according to the invention. This throwing wheel 1 has a housing 2 around which a number of blades 3 are rotatable.

A second housing (not shown) may optionally be provided around the throwing wheel 1 for protection.

Figure 2 shows a cross section of the jet wheel 1 according to the invention. A rotatable wheel 4 is provided in the housing 2. This rotatable wheel 4, which is designed as a bushing, has a number of holes 5 in the circumferential wall. The rotatable wheel 4 is placed in the housing such that, in the direction of rotation R, the space between the rotatable wheel 4 and the housing 2 towards the outlet opening 6 increases. Particle material D flows centrally into the housing 2 and is pumped through the rotatable wheel 4 through the holes 5 to the slag housing-like space between the rotatable wheel 4 and the housing 2.

The blades 3 rotate synchronously with the rotatable wheel 4. each blade 3 is curved, a first blade surface 7 adjacent the housing 2 making an obtuse angle ce with the tangential direction T. This vane surface 7 is completely flat and it offers the possibility, after a package of particles has been scooped up from the outlet opening 6, to spread over this flat first vane surface 7. Due to the rotation of the vanes 3 this package will move to the surface. 1 844 5 '4 second vane surface part 8, which is curved such that the distal end encloses an acute angle β with the tangential direction T. By this curved second vane surface part the package is accelerated in order to leave the vane 3 at a high speed and to form a particle beam with a small spread.

101 84 4 5%

Claims (6)

Device for forming a particle beam, which device comprises: - a housing with an inlet opening for supplying particles and an outlet opening; 5. a pump wheel rotatable in the housing for transporting the particles from the inlet opening to the outlet opening; - blades which are substantially coaxial and rotatable in synchronism with the pump wheel outside the housing for accelerating the particles and for forming a particle beam, characterized in that the radial distance between the pump wheel and the housing increases in the direction of rotation of the pump wheel, In order to form a space, this space opening into the discharge opening. 2. Device as claimed in claim 1, wherein the rotatable pump wheel comprises a bush, wherein holes are arranged in the peripheral wall of the bush and the inside of the bush connects to the inlet opening. 3. Device as claimed in claim 1 or 2, wherein each blade is curved, the blade surface adjacent the housing forms an obtuse angle with the tangential of the housing surface and the blade surface near the distal end of the blade forms an acute angle with the tangential of the housing surface. 4. Device as claimed in claim 3, wherein a first collecting part of the vane surface adjacent to the housing is substantially flat seen at least in the radial direction. Device as claimed in claim 3 or 4, wherein a second acceleration part of the vane surface is curved adjacent the distal end in order to accelerate the particles. Device as claimed in any of the foregoing claims, wherein the blades are detachable. 101 84 4 5 Ί