MXPA95005093A - Rotary atomizer with camp element - Google Patents

Abstract

The present invention relates to a rotary atomizer with a bell element that can be mounted on a rotary shaft of a drive motor, which includes: an outer overflow surface, a spray edge on a front side of said bell element an outer lateral surface on the perimeter of said bell element, extending from said spray edge, a hose line in fluid communication with a source of cleaning fluid, wherein a material to be atomized is moved from an interior space of said bell element towards said outer overflow surface leading to said spray edge on said front side of said bell element, wherein said cleaning fluid moves from said hose line to said outer side surface of said bell element, said cleaning fluid flows from a position in fluid communication with said line of ma ng to said outer side surface by means of centrifugal action, and is distributed through said outer surface to rinse and clean said outer side surface, and an interior space of said bell element leading to at least one outer rinsing channel distributed around a rotating shaft which is conducted in an outer annular space located at a point of said bell element remote from said side between a rear edge of said outer surface and a cube section of said bell element, and from which it flows said cleaning stream, through said back edge inside said outer surface

Description

ROTARY ATOMIZER WITH HOOD ELEMENT BACKGROUND OF THE INVENTION The invention relates to a rotary atomizer with a bell element that can be mounted on the rotary shaft of the drive motor. Sprayers of this type are used in electrostatic paint systems, for example, to paint motor vehicles in series. From German Patent Application 4,306,799 A1 a rotary atomizer with a bell element rotating around a central tube construction is known. A material inlet is fixed coaxially in position at the rear of the bell element. Said tube construction contains a channel separated from the paint channel, in that the rinsing agent (by what is meant, in particular, a paint solvent) enters the interior space of the bell element. As the rinsing agent channel of the tube construction is separate from the paint channel, it is possible to rinse the bottom of the hood and a distribution or deflection unit installed in the bottom of the hood, without first removing the painting of the paint channel and without having to accept the associated losses. The mutually separate channels of the tube construction according to this invention open to an annular space attached to the diverting unit, whereby the diverting unit is removably inserted in the canopy dome, as is known from the Application German Patent DE-GM G 9.319.555.9. In the known atomizers there is the problem that, during operation, paint particles may fall on the diverging external surfaces of essentially conical form of the bell element forming the perimeter of the bell. Said paint particles are separated and can stain the article to be coated, especially after changing the paint. Therefore, it is necessary to create means for cleaning said outer surfaces. A solution to the problem is known from German Patent Application DE-GM G 8,607,841.0, which describes the placement of a separate channel for the rinsing agent at a distance from the central paint tube in an outer radial region of the housing of the atomizer and its connection to an external source of rinsing agent and its supply to jets directed to the conical outer surface of the bell element. Radially outside the jets of rinse agent there is a set of air deflector jets, parallel to the axis, whose radial separation from the axis of rotation must correspond approximately to the largest radius of the outer surface of the spray hood, and whose purpose is usually to provide for the control of the shape of the spray coating material from the atomizer dome. A separate control system including a valve, a valve actuating mechanism and a program control, is required for the rinsing agent supplied from the outside. The primary method used in other known rotary atomizers is to spray the outer side surface with rinsing agent from jets that open to the outside; however, this method has the disadvantage that, due to the rebound effects, the atomizer will become wet and, therefore, will stain surfaces other than those that are cleaned, for example, the positions located axially behind the bell element and / or on the external electrodes to apply an electrical charge to the coating material. In the case of rinse liquids with relatively good conductivity, high-voltage insulation problems also arise. It is also known the provision of channels that lead from the inside of the bell element to the outside, but its purpose is to drain the rinsing liquid that is collected in the interior space in an unplanned manner or after a cleaning operation. Thus regular rinsing of an external surface is not possible. SUMMARY OF THE INVENTION The present invention relates to specifying a rotary atomizer that will make it possible to clean the outer side surface of the bell element without the usual splashes and preferably also with less expense than before. This problem is solved with a rotary atomizer according to the present invention. The rotary atomizer has a bell element that can be mounted on a rotary shaft of a drive motor. The rotary atomizer includes an outer overflow surface, and a spray edge on a front side of the bell element. The rotary atomizer also includes an outer side surface located on the perimeter of the bell element extending from the spray edge and a hose line in fluid communication with a source of solvent or rinsing agent. A material to be atomized is displaced from an interior space of the bell element to the outer overflow surface leading to the spray edge on the front side of the bell element. A solvent or rinsing agent is moved from the hose line to the outer side surface of the bell element. The solvent or rinse agent flows from a position in fluid communication with the hose line to the outer side surface by means of centrifugal action and is distributed on the outer surface to rinse and clean the outer side surface. The advantage of the invention is that the substantially conical, forwardly deflected outer surface of the bell element is completely and reliably cleaned by the rinsing agent which preferably comes from the interior of the bell element and flows around the rim. rear axial of said outer surface. The invention avoids the undesirable wetting of other areas of the atomizer. Simultaneous cleaning is achieved, uniform and without splashing the outer surface of the dome of the hood. In preferred embodiments, the cleaning can also be controlled by the same system as is needed in normal operation for rapid regular rinsing or temporary rinsing of the bell element, and possibly the central distributor or diverter unit. That is, without a separate valve and no additional control effort, due to the bifurcation of the standard quick-rinse valve. The invention will now be explained in more detail, with reference to an embodiment, the drawing of which is described below. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 depicts a bell element of a rotary atomizer and schematically illustrates an air control ring mounted on the rotary atomizer. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT The bell element 1 is used to spray a coating material, such as a pigmented paint soluble in water or otherwise. The coating material flows over the overflow surface 2 to the spray edge 3. A hub section 4 is screwed into the open end of a gap of the drive motor (not shown) of the rotary atomizer. The mounting structure makes possible a small, compact and light hood unit, and a relatively short paint tube 7 around which the bell element 1 rotates. As the front end of the paint tube 7 is located coaxially with the axis of the rotation and serves as a nozzle, the coating material to be sprayed is directed to the bell element. On the other hand, during the painting change, a rinsing agent usually flows through the paint channel of the paint tube 7. The paint tube 7 is a part of a fixed tube element 8 with additional axial holes 9 advancing from eccentric shape and parallel to the paint tube. Since these axial holes 9 are located outside the paint tube 7, the interior space of the bell unit can be rinsed without using the paint tube 7, and without the need to accept, for example, paint losses or large quantities of rinsing agent. This can be useful when a regular cleaning is necessary not only during the painting change, but also for other reasons. The paint tube 7 and the holes 9 open into an annular element 13 attached to the bypass unit 10. The bypass unit is detachably inserted in the bell element 1. The holes 9 are opened lengthwise of parallel axes in the annular element 13 of the diverter unit 10 and are fed by a rinsing agent channel 9 'which is separated from the paint channel of the paint tube 7. The channel 9' is located in a radially expanded portion 8 'of the tube element 8. Between the front end face 12, advancing radially, of the unit 8 'and the rear end face 17 of the annular element 13 has formed an annular space 29 surrounding the tube construction. At its outer radial end, the space 29 is widened to the inner wall of the bell element and can be expanded axially in the channel in this position. In this region, on the outer perimeter of the annular space 29, one or more connection channels 20 are opened connecting the annular space 29 with the rinsing agent channel 9 '. The connecting channels 20 extend from the rinsing agent channel 9 ', advancing radially outwards, and / or tilting forward in front of the radial direction. As is evident from the figure, the outer perimeter of the bell element 1 is formed by a conical outer surface 5, without a step, which deviates forward. The surface 5 extends between the spray edge 3 and a ring-shaped rear edge 6 which faces away from the spray edge 3. An annular space 15 opens axially to the rear part and can have, for example, a approximately U-shaped cross section forming a portion of the outer surface of the bell element. Said annular space 15 is connected radially to the edge 6 on the rear side of the bell element 1 between the conical outer surface 5 and the axial frontal region of the hub unit 4.

At the inner radial end of the radially extending base or inner surface 16 of the annular space 15, external rinsing channels 18 have been placed at uniform angular intervals around the axis of rotation. The channels 18 run from the perimeter of the annular space 29, advancing radially outwards, and are inclined forwardly facing the axial direction and pass through the hub unit 4 of the bell element 1. To clean the conical outer surface 5, the agent The rinse aid or solvent to be used for this can be taken from the rinsing agent channel 9 'of the central tube construction. In a rotating dome, the rinsing agent flows due to the centrifugal force through the connecting channel 20, the annular space 29 and the channel 18, traverses the base surface or inner surface 16 and the radial outer side wall of the annular space 15. and, finally, it passes over the trailing edge 6 of the bell element 1. From there it is distributed through the outer conical surface 5. This preferably takes place simultaneously with the rinsing process to clean the holes located inside and above. the deviation unit 10, as well as the overflow surface 2, by means of the rinsing agent that emerges from the axial holes 9; that is, automatically and without a separate control unit. A lower edge of preferably rounded bell 6 promotes the transition without splashing from the inner surface to the outer surface. The annular space 29 has a larger diameter (on its outer perimeter) than the gap 25 formed between the hub section 4 and the fixed tube construction. This prevents the rinse liquid from collecting on the outer perimeter of the annular space 29 due to the centrifugal force, and then leaving the bell element through the interval 25 and entering, for example, in the rear tank. In addition or instead of this, a dynamic seal 26 can be provided in the range 25 which prevents the rinsing agent from flowing out. In contrast to the schematic representation of the figures, the annular space 15 can also have a different structure. For example, the space 15 can be configured with an outer side wall inclined radially outwardly or curved. The shape of the annular space 15 may depend in particular on the number of existing outside rinsing channels 18. If only one or a few external rinsing channels are provided as a simplification of the design, it may be convenient to provide, on the radially outer wall of the annular space 15, for example, near its base, a relatively small, ring-shaped collecting channel (not shown) or diverting the lower edge 6 radially inward to the rinsing agent manifold. An annular unit 30 is preferably mounted in the rotary atomizer behind the rotating bell element 1 in the radially outer region. Said annular unit contains air jets 31 which open axially, distributed around the perimeter and connected to a source of compressed air (not shown). Air jets 31 apply the rinsing agent or solvent flowing through the outer surface 5 with control air. Said axial air jets have a radial separation (in the illustrated example) of the axis of rotation approximately equal to half the diameter of the conical outer surface 5 near its rear end and, therefore, only slightly greater than half the diameter of the edge 6. Several sets of air nozzles with different diameters and / or opening directions can be provided. It has been found that a considerable vacuum pressure is created due to the control air that arrives radially and enters relatively a lot. That is, the central air reaches the rear end of the outer surface 5, which extends uniformly, possibly decreasing, through the entire outer surface 5 to the point of the largest diameter at the rinsing edge 3. Due to said pressure of vacuum, the solvent flowing above the edge 6 is in intimate contact with the entire outer surface 5, so that the cleaning element is considerably improved.

The cleaning of the outer surface can also be achieved without the described effect of the control air, because the solvent flowing over the edge 6 is already glued to the outer surface 5 due to the effects of natural adhesion. The greater the radius of rounding at the edge 6, the more prominent this adhesion effect is. The amount of taper of the conical outer surface 5 also has an effect on how well the solvent is applied. The invention is not limited to the sample design described above. In particular, it is not necessary to derive the rinsing agent or solvent from the central tube construction, but it can flow through another route into the bell element or to a point located radially inside the outer surface to be cleaned or a corresponding space to the annular space 15, if any, or to be directed to a corresponding axial recess and to flow laminarly from there to the outer lateral surface at the bell perimeter. In this case, a separate control valve can be provided which can be used for separate control of the external rinsing process.

Claims (20)

1. CLAIMS 1. A rotary atomizer with a bell element that can be mounted on a rotary shaft of a drive motor, including: an outer overflow surface; a spray edge on a front side of said bell element; an outer side surface on the perimeter of said bell element extending from said spray edge; a hose line in fluid communication with a source of cleaning fluid; wherein a material to be atomized is displaced from an interior space of said bell element to said outer overflow surface leading to said spray edge on said front side of said bell element; and wherein said cleaning fluid is displaced from said hose line to said outer lateral surface of said bell element; characterized in that said cleaning fluid flows from a position in fluid communication with said hose line to said outer side surface by means of centrifugal action and is distributed by said outer surface to rinse and clean said outer side surface. The rotary atomizer according to claim 1, wherein said position in fluid communication with said hose line is located in a space formed in said bell element. The rotary atomizer according to claim 1, wherein said cleaning fluid flows by centrifugal force around a ring-shaped rear edge of said outer surface and is evenly distributed throughout the entire surface between said shaped edge. of hoop and said spray edge. The rotary atomizer according to claim 1, wherein an interior space of said bell element leads to at least one of the outer rinsing channels distributed around an axis of rotation leading to an outer annular space that is located in a point of said bell element remote from said front side between a rear edge of said outer surface and a hub section of said bell element, and from which said cleaning fluid flows, said rear edge, to said outer surface. The rotary atomizer according to claim 4, wherein said annular space adjoining said rear edge is open to said exterior on a rear side of said bell element. The rotary atomizer according to claim 5, wherein said outer rinsing channels are open at an inner radial end of an inner surface, extending generally radially, of said annular space. The rotary atomizer according to claim 6, wherein a collecting channel for said cleaning fluid is placed in an outer radial side wall of said annular space. The rotary atomizer according to claim 1, wherein said bell element rotates about a fixed coaxial central tube construction disposed in a rear opening facing away from said overflow surface, containing a separate rinsing agent channel of said tube construction, whereby said cleaning fluid is moved axially to an interior space of said bell element, wherein at least one of the outer rinsing channels connects said rinsing agent channel of said tube construction with a position on an outer side of said bell element, from where said cleaning fluid flows through said outer side surface of said cord element leading to said spray edge. The rotary atomizer according to claim 8, wherein said outer surface of said bell element leading to said spray edge slopes essentially conically, where jets of air opening to said outer surface, connectable to a source of compressed air, supply control air to said cleaning fluid flowing through said outer surface. 10. The rotary atomizer according to claim 9, wherein a vacuum pressure sucks said cleaning fluid against said outer surface which is generated by said air jets distributed around said axis of rotation of said outer surface. The rotary atomizer according to claim 10, wherein said outer rinsing channels emanate from said outer perimeter of an inner coaxial annular space located in a rear portion of said bell element, said annular space being in fluid communication with a channel of connection leading to said line of rinsing agent. The rotary atomizer according to claim 11, further comprising a central diverting unit coaxially located within said overflow surface in said bell element, through which said material to be atomized is divided into secondary streams, of which a first secondary current flows along a reverse side of said diverting unit to said overflowing surface, and a second secondary flow travels through a central opening to a front side of said diverting unit and from there to said overflowing surface, and that is removably inserted with a rear annular element into said bell element, wherein said annular space is located between an end rear face of said annular element and an end front face of a radially expanded part of said tube construction central containing said rinsing agent channel. The rotary atomizer according to claim 12, wherein a seal is provided between said tube construction and said hub section of said bell element, preventing the accidental exit of cleaning fluid from said bell element. The rotary atomizer according to claim 13, wherein said inner annular space has a larger diameter than said opening located between said hub section and said fixed tube construction. The rotary atomizer according to claim 14, wherein said connecting channel leads from said rinsing agent channel of said central tube construction radially outward toward said annular space. 16. A rotary atomizer with a bell element that can be mounted on a rotary shaft of a drive motor, including: an outer overflow surface; a spray edge on a front side of said bell element; an outer side surface on the perimeter of said bell element extending from said spray edge; a hose line in fluid communication with a source of cleaning fluid; wherein a material to be atomized is displaced from an interior space of said bell element to said outer overflow surface leading to said spray edge on said front side of said bell element; and wherein said cleaning fluid is displaced from said hose line to said outer lateral surface of said bell element; characterized in that said cleaning fluid flows from a position in fluid communication with said hose line to said outer side surface by means of centrifugal action and is substantially distributed over said outer surface to rinse and clean said outer side surface, wherein said position in Fluid communication with said hose line is located in a space formed in said bell element. 17. The rotary atomizer according to claim 16, wherein at least one of the outer rinsing channels is disposed between an interior space of said bell element and an outer annular space that is located at a point of said element remote from said front side between a rear edge of said outer surface and a cube section of said bell element, and from which said cleaning fluid flows through said rear edge to said outer surface, said channels being distributed around an axis of rotation of said atomizer. 18. The rotary atomizer according to claim 16, wherein said bell element rotates around a fixed coaxial central tube construction disposed in a rear opening facing away from said overflow surface containing a rinsing agent channel separate from said construction of tube whereby said cleaning fluid is axially displaced to an interior space of said bell element, wherein at least one of the outer rinsing channels connects said rinsing agent channel of said tube construction to a position on an outer side of said bell element, from where said cleaning fluid flows through said outer side surface of said bell element leading to said spray edge, where air jets opening to said outer surface, connectable to an air source compressed, supply control air to said cleaning fluid flowing through said supe outer surface. The rotary atomizer according to claim 18, further including a central diverting unit coaxially located within said overflow surface in said bell element, through which said material to be atomized is divided into secondary streams, of which a first secondary current flows along a reverse side of said diverting unit to said overflowing surface, and a second secondary flow travels through a central opening to a front side of said diverting unit and from there to said overflowing surface, and that is removably inserted with a rear annular element into said bell element, wherein said annular space is located between an end rear face of said annular element and an end front face of a radially expanded part of said tube construction central containing said rinsing agent channel. The rotary atomizer according to claim 19, wherein a seal is provided between said tube construction and said hub section of said bell element, preventing the accidental exit of cleaning fluid from said bell element. ROTARY ATOMIZER WITH HOOD ELEMENT SUMMARY OF THE DESCRIPTION A rotary atomizer with a bell element (1) that can be mounted on the rotary shaft of a drive motor includes an outer overflow surface (2), a spray edge (3) ) on a front side of the bell element (1), an outer side surface (5) on the perimeter of the bell element extending from the spray edge (3), and a hose line (9) in fluid communication with a source of cleaning fluid. The rinsing of the outer surface (5) on the perimeter of the bell element (1) of a rotary atomizer is facilitated. The rinsing agent is directed without splashing, by centrifugal force, from the inside to the outer surface (5) and is evenly distributed around the perimeter. The rinsing agent can be derived in the center of a quick rinse valve and reach a collection space (29, 15) located radially inside the outer surface (5), from where it flows at the rear edge, preferably rounded ( 6) of the element's dome. Alternatively, the rinsing agent can be supplied separately by a separate valve.