Patent Grant
9073068
The present invention relates to a spray head for generating a flat jet of paint at a paint spray gun or a paint spray lance or a spray head.
According to the present invention, the spray head can also be used for other air-propelled application processes that make use of the function according to the present invention of generating a flat jet at the spray head.
There are a number of fundamental technical principles in the field of application processes using spraying, for example, when spraying paint or spraying varnish. As well as the so-called airless processes that atomize paints at high pressure and apply them to a surface, there are many processes using compressed air. In these, a paint jet emerging from a nozzle is atomized by means of quantities of air (sheathing air) that flow past and is thus transported as atomized sprayed paint toward a working plane. The working plane that is arranged at an appropriate working distance for applying a coating is in this way struck by the paint jet and the paint is thus applied to it. Appliances that operate with compressed air, as well as so-called HVLP (high-volume low-pressure) appliances are, inter alia, known from the prior art and differ in some operating parameters, for example, the pressure of the air at the nozzle.
This genre of appliance from the prior art is suitable for providing a flat jet of paint, which has advantages when paint is applied to a surface. In comparison with a radially symmetrical round paint jet, a flat jet provides greater homogeneity in the application of paint, similar to applying it with a paintbrush or a roller, giving a much higher quality of paint coverage.
Paint spraying devices are known from the prior art, for example from EP 0 596 939 B1, in which a radially symmetrical round paint jet, emerging from a paint nozzle, is deformed by air deflection means which are arranged at the sides of the paint nozzle and take the form of air horns, so that a generated flat jet of paint is created in the region of a working plane.
However, the flat jet profiles which are generated using the prior art often create an inadequate shaping of the jet profile, in particular when highly viscous paint materials such as, for example, wall paint, or viscous varnishes are used. An improved flat jet profile is always desirable as the quality of the work and quality of the resulting paint coverage is greatly dependent on the jet profile of the paint jet provided by a paint spray gun.
The object of the present invention is therefore to further develop a spray head for generating a flat jet of paint at a paint spray gun or at a paint spray lance, which spray head overcomes the disadvantages of the prior art.
The present invention relates to a spray head for generating a flat jet of paint at a paint spray gun or at a paint spray lance, which spray head comprises an air gate, a paint nozzle with a needle valve and an air cap arranged downstream from the air gate in the direction of air flow. The spray head for a paint spray lance is preferably designed without a needle valve if, for example, a viscous construction material such as, for example, mortar is to be sprayed. The air gate hereby has a centrally arranged through opening for the passage of the paint nozzle. Also situated in the air cap is a centrally arranged through opening for the passage of the paint jet or the paint nozzle, and of a flow of sheathing air surrounding the paint jet or the paint nozzle. Depending on whether the paint spray gun or paint spray lance has a nozzle for internal or external mixing, the paint nozzle, or the jet of paint or construction material which has already been ejected from the nozzle, passes through the central opening in the air cap.
Furthermore, the spray head according to the present invention comprises at least one air through opening which is radially spaced apart in the air gate from the central through opening, and at least one air deflection means which is preferably designed as an air horn and which is arranged on an air through opening, associated therewith, in the air cap. The air horn deflects an air jet passing through toward the paint jet or the paint/air jet, and communicates with a source of air in or on the body of the gun via the air through opening in the air cap and an air through opening in the air gate, which openings have a similar radial spacing from the center of the air cap or the air gate.
According to the present invention, the spray head is characterized in that the central through opening in the air cap is designed as a slot-shaped air cap opening with a first longitudinal axis of this air cap opening and first transverse axis of this air cap opening which is shorter than the longitudinal axis.
The spray head according to the present invention with a slot-shaped air cap opening generates by virtue of its shape a flat jet that is widened during its travel between the spray head and a working plane.
In a further development of the spray head, the spray head is characterized in that the air deflection means is arranged on a narrow side of the central air cap opening along the longitudinal axis of this slot-shaped opening, and a paint jet emerging from the spray head is widened along the transverse axis of the slot-shaped air cap opening.
By virtue of its slot-shaped air cap opening, the spray head according to the present invention generates a widened flat jet that is widened in the direction of the transverse axis of the slot-shaped air cap opening, so that a horizontally extending slot in the air cap results in a vertically extending flat jet.
In a further development of the spray head according to the present invention, the paint nozzle is also designed as a slot-shaped paint nozzle.
In this way, the formation of the flat jet is amplified.
In a preferred embodiment of the arrangement according to the present invention, it is provided that two air deflection means, preferably two air horns, are provided symmetrically with respect to the center of the air cap.
The two air deflection means, which are arranged at the respective narrow ends of the slot-shaped opening in the air cap, have an amplifying effect, caused by the flow of air passing through them, from both sides on the formation of the flat jet, so that a thereby improved flat jet is provided for coating a surface.
In another preferred development of the subject of the present invention, pressure-relief openings are provided which allow an additional outlet of air from the paint spray gun body without the emerging air affecting the paint jet generated, in particular the flat jet.
By virtue of such pressure-relief openings, it can be ensured that a sufficient air flow volume can always be delivered, for example, to provide sufficient cooling for an air-supply blower. This is particularly necessary when the flow of air delivered is used, for example, as a flow of cooling air, as is the case with many of the radial blowers used in HVLP devices.
In a development of the spray head according to the present invention, means are additionally provided which supply air alternatively to either the pressure-relief openings or the air deflection means. In this way, a maximum available flow of air can be used, although the air deflection means may possibly be switched off for particular applications. A corresponding principle for use with a round-jet paint nozzle is disclosed in the prior art in EP 0 596 939 B1.
The advantageous embodiments of the means for alternatively switching between the pressure-relief openings or the air deflection means will be described in detail in this description with reference to the exemplary embodiments. Reference is explicitly made here to the details of the exemplary embodiments.
The present invention also relates to a spray head for generating a flat jet of paint at a paint spray gun or at a paint spray lance, which spray head comprises an air guide, in particular an air gate. It is also conceivable that a paint spray gun or paint spray lance is provided with a spray head according to the present invention without an air gate, for example when the paint nozzle is suspended correspondingly centrally in the air guide of the paint gun body and there are no air deflection means in the region of the air cap. An air guide is necessary only when different air through openings are correspondingly made to coincide with different air outlet openings, in order in this way to provide other necessary functions in addition to simply generating a flat jet.
The further spray head according to the present invention for a paint spray gun furthermore comprises a paint nozzle with a needle valve, and an air cap which is arranged downstream from the air guide in the direction of the air flow and has a centrally arranged through opening for the passage of a paint jet or a paint nozzle and of sheathing air surrounding the paint jet or the paint nozzle. The spray head of a paint spray lance for spraying viscous construction material preferably does not have a needle valve. The spray head is characterized in that the central through opening in the air cap is designed as a slot-shaped opening, the slot-shaped opening having a first longitudinal axis of the air cap opening and a first transverse axis of the air cap opening which is shorter than the longitudinal axis.
In this way, a spray head is provided which can be manufactured simply and cost-effectively, generates a flat jet, and requires no additional air deflection means. It may also be possible to dispense with an air gate, in particular when the gun body is used as an air guide.
This further spray head according to the present invention can be used in many applications which can include a wide variety of coating materials.
In a development of the further spray head according to the invention with no air deflection means, it is provided that the paint nozzle is likewise designed as a slot-shaped nozzle. A preferred embodiment of the spray head according to the invention generates a flat paint jet which strikes a working plane that is placed at a working distance from the spray head and is arranged perpendicularly to the spraying direction, wherein the longitudinal axis of the flat jet, and a transverse axis of the flat jet which is shorter than the longitudinal axis of the flat jet, are rotated by 90° about the spraying direction with respect to a longitudinal axis of the slot-shaped air cap opening and the transverse axis of the slot-shaped air cap opening.
In this way, a flat jet is likewise generated which, for example, when the slot-shaped opening of the air cap is arranged horizontally, generates a vertically directed flat jet on a working plane.
The principles according to the present invention of a spray head for generating a flat paint jet at a paint spray gun will be explained further below. The term passage is hereby used for perforations, through which a fluid passes, of internally situated components. The term openings is used for perforations in components, which perforations allow air to enter the externally situated region from the internally situated region. The arrangement of multiple passages or their ends one after the other in an opening is termed below as a channel, in particular an air channel.
In detail,
The paint nozzle 5 is here designed as a needle valve and has a slot-shaped nozzle outlet. The needle head 7, which is introduced into the paint nozzle 5 from the rear, has a wedge shape 8 at its tip which matches the slot-shaped nozzle opening. A valve seat 9, adjoined by a guide 11 and a sealing barrel 12 after a tapered portion 10, adjoins the wedge shape.
The paint nozzle 5 is here suspended centrally in the air gate 4 via connecting ribs 13 (see
The air gate 4 has fixing lugs 20 and 21 on its upper side which, when assembled (
The air control disk 6 also comprises an actuating pin 31 and a centrally arranged opening that permits the passage of the paint nozzle and a surrounding flow of sheathing air.
The air cap 3 is arranged on the spray head 1 according to the present invention downstream in the direction of the flow of paint or air. The air cap 3 comprises on its rear side corresponding fixing grooves 22 that make a non-rotational connection to the air gate 4. On its front side, the air cap comprises two air deflection means in the form of air horns 40 which are arranged at the respective narrow ends along a longitudinal axis of a slot-shaped central opening 41 in the air cap. The air horns 40 have shaping air outlets 42 that direct an emerging jet of air toward a jet of paint/air emerging through the slot-shaped central opening 41. Furthermore, the air cap 3 has pressure-relief openings 43 that are arranged at a radial spacing from the slot-shaped central opening 41, and the flow of air emerging from them has no effect on a jet of paint/air emerging through the central opening. According to the present invention, the components can be produced, for example, as either a metal part or as injection-molded plastic parts, depending on what quality requirements and material properties are determined for the individual components. It is also conceivable, for example, for the paint nozzle to be made from metal, the air gate to be made from plastic, and the air cap likewise to be made from plastic, and to use other variations of combinations of materials as part of the manufacture of the components.
The spray head according to the present invention is suitable for applications with air-propelled application processes that atomize the paint using in particular compressed air at an air pressure of no more than 10 bar, or in HVLP processes use a nozzle pressure of less than 0.7 bar (at 10.0 psi) in order to meet HVLP conventions.
A course of a flow of air 50 is also shown by way of example in
The actuating pin 31 on the air control disk 6 penetrates through an elongated hole 63 when the spray head is assembled.
A rotary actuating means 64, which is clipped over the union nut 61 via clamping wings 65, is arranged in front of the union nut 61. The rotary actuating means 64 has a catch 66 which engages with a protrusion at the front of the actuating pin 31 in the mounted state, and carries the actuating pin 31 along. In this way, the rotational movement 62 can be transmitted via the rotary actuating means 64 to the actuating pin 31, and it is thus possible to switch easily between the guidance of air through a shaping air channel and the guidance of air through the pressure-relief channels.
Shaping air inlets 70 are arranged on the rear side of the air cap 3, through which a flow of shaping air enters an air horn 40 and can act on a jet of paint/air via the shaping air outlet opening 42 (see
The air cap 3 has on its rear side a depression 71 which is dimensioned for receiving the air control disk 6, so that the air control disk 6 can be arranged between the air cap 3 and the air gate 4 when the spray head is assembled, but is not held secure by the pressure applied by the union nut 61 and instead remains capable of rotating inside the depression 71.
Depending on the application and the material used, the dimensions of the slot-shaped paint nozzle 5, the slot-shaped central opening 41 and thus the annular gap 80 are adapted so as to optimize the atomization of the material to be applied.
The annular gap cap 102 has a slot-shaped central opening 106 in its central region, wherein this slot-shaped central opening 106 is surrounded laterally by corresponding projections and deformations to improve the fit when the horn cap 101 is assembled with the annular gap cap 102. Furthermore, the annular gap cap has air passages 107 which are arranged, symmetrically opposite each other, at a radial spacing on the narrow sides of the slot-shaped central opening 106. The upper surface of the annular gap cap 102 is moreover perforated by holes 108 which are not used as air passages.
An air gate 110, which has a paint nozzle 112 with a slot-shaped nozzle opening arranged at its center on connecting ribs 111, is arranged upstream from the horn cap and the annular gap cap, in the direction of the flow of air. The air gate 110 has air passages 113 which are radially spaced apart from a center by a distance that is selected so that it corresponds to the radial spacing of the air passages 107 in the annular gap cap 102, and the pressure-relief openings 105 in the horn cap 101, and the shaping air outlet channels 104 in the air horns 103 of the horn cap 101.
Fixing grooves 114 are provided on the rear side of the air gate 110 and allow the arrangement to be fixed inside a gun body.
Furthermore, studs 115, onto which the annular gap cap is pushed and which penetrate the holes 108, are arranged on the upper surface of the air gate 110. In this way, the annular gap cap 102 is connected to the air gate 110 so as to be fixed in rotation, as a result of which, in a similar fashion to the description of
The rotary actuating means 122 clips onto the union nut 121 via clamping wings 123 and has catches 124 which carry the air horns 103 of the horn cap 101 along when a rotational movement 125 is effected. When assembled, the air cap 103 is arranged so that it bears rotatably on the annular gap cap 102 so that the air passages on the rear side of the horn cap 101, which open into the pressure-relief openings 105 or the shaping air outlets 104, can be rotated into a position above the air passages 107. An air channel can thereby be formed alternatively through the air passages 113 in the air gate 110, the air passages 107 in the annular gap cap 102, and alternatively through the pressure-relief openings 105 in the horn cap 101 or the shaping air outlets 104 in the horn cap 101.
Shaping air inlets 130, which open into the shaping air outlets 104 of the air horns 103, are provided on the rear side of the horn cap 101. The pressure-relief openings 105 are arranged in a radially circumferential fashion, offset to the shaping air inlets 130, it being possible for the pressure-relief openings 105 to be made to coincide with the air passages 107 in the annular gap cap 102 that correspond to the shaping air inlets 130 by rotating the horn cap 101, and hence form pressure-relief air channels where the flow of air does not act on a centrally emerging jet of paint/air.
Two elongated holes 131 are moreover provided on the rear side of the horn cap 101, into which elongated holes 131 the studs 115 (see
A spray head 1 according to the present invention is shown in
A spray pattern 201 which strikes a working surface has a transverse extent 202, wherein a normal processing distance should be chosen for the working surface that corresponds, for example, to the distance of a varnisher from a wall or a workpiece which is to be varnished. The projected course of the paint jet is indicated by a schematically illustrated spray limit 203. The transverse extent 202 is substantially parallel to the longitudinal extent of the slot 204, which corresponds to the slot width of the paint nozzle or the slot width of the slot-shaped central opening 41. Depending on the position of the air control disk 6, shaping air openings 42 provide a flow of shaping air which acts laterally on the emerging jet of paint/air and deforms the spray limit 203 so that it approaches a central spraying axis.
In this position, the spray pattern 201 has a much greater longitudinal extent 210, the distance from the working plane being chosen so that it corresponds to the distance in
The present invention is not, however, limited to the exemplary embodiments shown.
Rather, it encompasses all arrangements that may be of use in the approach according to the present invention. Other types of application are also conceivable in which the spray head arrangement according to the present invention can be used for air-propelled application processes.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2009 036 147 | Aug 2009 | DE | national |
| 10 2009 053 449 | Nov 2009 | DE | national |
This application is a continuation of International Application No. PCT/DE2010/000899 filed Jul. 30, 2010, which designated the United States, and claims the benefit under 35 USC §119(a)-(d) of German Application No. 10 2009 036 147.2 filed Aug. 5, 2009 and German Application No. 10 2009 053 449.0 filed Nov. 17, 2009, the entireties of which are incorporated herein by reference.
| Number | Name | Date | Kind |
|---|---|---|---|
| 2139133 | Paasche | Dec 1938 | A |
| 4884742 | Bekius et al. | Dec 1989 | A |
| 4948053 | Hufgard | Aug 1990 | A |
| 5060869 | Bekius | Oct 1991 | A |
| 5102051 | Smith et al. | Apr 1992 | A |
| 5217168 | Svendsen | Jun 1993 | A |
| 5435491 | Sakuma | Jul 1995 | A |
| 7407572 | Steffens et al. | Aug 2008 | B2 |
| 8590810 | Woodgate et al. | Nov 2013 | B2 |
| Number | Date | Country |
|---|---|---|
| 101001937 | Jul 2007 | CN |
| 0 596 939 | Dec 1998 | EP |
| 1 118 387 | Jul 2001 | EP |
| 520 367 | Apr 1940 | GB |
| 520367 | Apr 1940 | GB |
| 520367 | Apr 1940 | GB |
| Entry |
|---|
| Chinese Search Report, Chinese Application No. 201080045648.0, dated Jun. 24, 2014 (2 pages). |
| Number | Date | Country | |
|---|---|---|---|
| 20120160935 A1 | Jun 2012 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/DE2010/000899 | Jul 2010 | US |
| Child | 13359907 | US |
