Abstract
A main body for a spray gun, in particular a paint spray gun, has at least one head region for attachment of a nozzle arrangement. The head region has at least one inner wall, one outer wall and one middle wall arranged therebetween. The walls are formed in encircling fashion and in one piece with the main body, with the front end of the middle wall set back in relation to the front end of the outer wall along an axis. This main body does not require any additional sealing element for sealing between the atomization air region and horn air region. The middle wall is well protected against damage even when a nozzle has been unscrewed, and the gun head can be of very compact design.
Claims
1. A main body for a spray gun having a head region for the attachment of a nozzle arrangement, wherein the head region has an inner wall, an outer wall and a middle wall arranged in between, wherein the inner, outer, and middle walls are formed in encircling fashion and in one piece with the main body, wherein a front end of the middle wall is set back in relation to a front end of the outer wall along an axis.
2. The main body according to claim 1, wherein the inner wall and the middle wall delimit a first air distribution chamber, and the middle wall and the outer wall delimit a second air distribution chamber.
3. The main body according to claim 1, wherein a first front surface is arranged between the inner wall and the middle wall, and a second front surface is arranged between the middle wall and the outer wall, wherein the first front surface has a first spacing to the front end of the outer wall along the axis, wherein the second front surface has a second spacing to the front end of the outer wall along the axis, with the first spacing greater than the second spacing.
4. The main body according to claim 3, wherein the first spacing is between 9 mm to 11 mm and the second spacing is between 4 mm to 6 mm.
5. The main body according to claim 3, wherein at least one of the first front surface and the second front surface has a groove.
6. The main body according to claim 3, wherein the second front surface has a groove with a base surface, wherein the base surface has a third spacing to the front end of the outer wall along the axis, and wherein the third spacing is smaller than the first spacing of the first front surface to the front end of the outer wall.
7. The main body according to claim 5, wherein a width of the groove substantially corresponds to a width of the first front surface or a width of the second front surface.
8. The main body according to claim 5, wherein the groove extends in a circumferential direction over 25% to 75% of a circumference of the first front surface or a circumference of the second front surface.
9. The main body according to claim 3, wherein the first front surface has at least one inner air outlet opening, and wherein the second front surface has at least one outer air outlet opening.
10. The main body according to claim 9, wherein the at least one inner air outlet opening of the first front surface extends over at least 85% of a width of the first front surface, and wherein the at least one outer air outlet opening of the second front surface extends over at least 85% of a width of the second front surface.
11. The main body according to claim 3, wherein the main body has at least two atomization air channels which extend from the first front surface into a fan control air distribution chamber, and/or wherein the main body has at least two horn air channels which extend from the second front surface into the fan control air distribution chamber, wherein the at least two atomization air channels are spaced apart from one another in a region of the first front surface and at least partially overlap in a region of the fan control air distribution chamber, and/or wherein the at least two horn air channels are spaced apart from one another in a region of the second front surface and at least partially overlap in a region of the fan control air distribution chamber.
12. The main body according to claim 1, wherein the front end of the inner wall is set back in relation to the front end of the middle wall along the axis.
13. The main body according to claim 1, wherein each of the inner wall, the middle wall and the outer wall is of circular design and the inner, middle and outer walls are arranged concentrically with respect to one another.
14. The main body according to claim 13, wherein the inner wall has an outer diameter of 13 mm to 15 mm, the middle wall has an outer diameter of 22 mm to 24 mm, and the outer wall has an outer diameter of 33 mm to 35 mm.
15. The main body according to claim 13, wherein the inner wall has an inner diameter of 11 mm to 13 mm, the middle wall has an inner diameter of 20 mm to 22 mm, and the outer wall has an inner diameter of 31 mm to 33 mm.
16. The main body according to claim 1, wherein the inner wall has an internal thread and the outer wall has an external thread.
17. A spray gun comprising the main body according to claim 1.
18. The spray gun according to claim 17, further comprising a nozzle having at least one material nozzle, an air cap, a first air-guiding region and a second air-guiding region, wherein the first air-guiding region guides air for atomizing material for spraying, and the second air-guiding region guides air for influencing a spray jet, wherein the first air-guiding region and the second air-guiding region are at least regionally separated from one another by the middle wall of the main body, a disc element arranged integrally on the at least one material nozzle, at least one impingement disc arranged on the at least one material nozzle, and by at least one part of the air cap, wherein the middle wall of the main body is of encircling design.
19. The spray gun according to claim 17, further comprising a nozzle with at least one material nozzle with a hollow portion for guiding through material for spraying and with a material outlet opening, and a disc element arranged on an outer circumference of the hollow portion, wherein the at least one impingement disc is arranged on a side of the disc element averted from the material outlet opening, and wherein the at least one impingement disc has an inner and an outer circumference, wherein the nozzle is arranged in or on the main body such that a first gap is formed between the outer wall and the at least one impingement disc.
20. The spray gun according to claim 18, wherein the nozzle is arranged in or on the main body such that a second gap is formed between the inner wall and the at least one impingement disc.
21. The spray gun according to claim 18, wherein the at least one impingement disc has at least one sealing surface which bears sealingly against a counterpart sealing surface on the middle wall of the main body.
22. The spray gun according to claim 18, wherein the at least one impingement disc is formed from a first portion and a second portion which together form a step, and wherein an outer diameter of the step substantially corresponds to the inner diameter of the middle wall of the main body.
23. A spray gun set comprising the main body according to claim 1, a first nozzle arrangement with a first nozzle and a second nozzle arrangement with a second nozzle, wherein the first nozzle arrangement is a low-pressure nozzle arrangement and the second nozzle arrangement is a high-pressure nozzle arrangement.
24. A method for producing the main body of claim 1, wherein the main body includes an air inlet channel, a first receiving opening for receiving an air flow rate regulating device, a second receiving opening for receiving a material flow rate regulating device, at least one horn air channel and one atomization air channel, wherein the main body is produced in one piece by 3D printing.
25. A method for converting a spray gun with a first nozzle internal pressure into a spray gun with a second nozzle internal pressure, wherein the first nozzle internal pressure is higher than the second nozzle internal pressure, wherein the method comprises: a. removing a high-pressure nozzle arrangement from or out of a main body of the spray gun, wherein the high-pressure nozzle arrangement has at least one nozzle with a material nozzle with a hollow portion for guiding through material for spraying and with a material outlet opening; b. arranging a low-pressure nozzle arrangement in or on the main body of the spray gun, wherein the low-pressure nozzle arrangement has at least one nozzle with a material nozzle with a hollow portion for guiding through material for spraying and with a material outlet opening.
26. The method according to claim 25, wherein the at least one nozzle of the high-pressure nozzle arrangement which is removed from or out of the main body of the spray gun has a disc element arranged on an outer circumference of the hollow portion and a first impingement disc, wherein the first impingement disc is arranged on a side of the disc element which averted from the material outlet opening and said first impingement disc has an inner and an outer circumference, and wherein the at least one nozzle of the low-pressure nozzle arrangement which is arranged in or on the main body of the spray gun has a disc element arranged on an outer circumference of the hollow portion and has a first impingement disc, wherein the first impingement disc is arranged on a side of the disc element averted from the material outlet opening, and said at least one nozzle has an inner and an outer circumference and has a second impingement disc which is arranged on a side of the first impingement disc averted from the material outlet opening, wherein the outer circumference of the first impingement disc of the low-pressure nozzle arrangement is smaller than the outer circumference of the first impingement disc of the high-pressure nozzle arrangement.
27. The method according to claim 25, wherein the method further comprises: a. removing a high-pressure air cap which is arranged over an air nozzle ring on the main body, wherein the high-pressure air cap has at least one central opening with a first diameter; b. arranging a low-pressure air cap which is arrangeable over an air nozzle ring on the main body, wherein the low-pressure air cap has at least one central opening with a second diameter, and wherein the second diameter is greater than the first diameter of the high-pressure air cap.
28. A method for converting a spray gun with a first nozzle internal pressure into a spray gun with a second nozzle internal pressure, wherein the first nozzle internal pressure is lower than the second nozzle internal pressure, wherein the method comprises: a. removing a low-pressure nozzle arrangement from or out of a main body of the spray gun, wherein the low-pressure nozzle arrangement has at least one nozzle with a material nozzle with a hollow portion for guiding through material for spraying and with a material outlet opening; b. arranging a high-pressure nozzle arrangement in or on the main body of the spray gun, wherein the high-pressure nozzle arrangement has at least one nozzle with a material nozzle with a hollow portion for guiding through material for spraying and with a material outlet opening.
29. The method according to claim 28, wherein the at least one nozzle of the low-pressure nozzle arrangement which is removed from or out of the main body of the spray gun has a disc element arranged on an outer circumference of the hollow portion and has at least one first impingement disc, wherein the first impingement disc is arranged on a side of the disc element averted from the material outlet opening, and said at least one nozzle has an inner and an outer circumference and has a second impingement disc which is arranged on a side of the first impingement disc averted from the material outlet opening, and wherein the at least one nozzle of the high-pressure nozzle arrangement which is arranged in or on the main body of the spray gun furthermore has a disc element arranged on an outer circumference of the hollow portion and a first impingement disc, wherein the first impingement disc is arranged on a side of the disc element averted from the material outlet opening and said first impingement disc has an inner and an outer circumference, wherein the outer circumference of the first impingement disc of the high-pressure nozzle arrangement is larger than the outer circumference of the first impingement disc the low-pressure nozzle arrangement.
30. The method according to claim 28, wherein the method further comprises: a. removing a low-pressure air cap which is arranged over an air nozzle ring on the main body, wherein the low-pressure air cap has at least one central opening with a first diameter; b. arranging a high-pressure air cap which is arrangeable over an air nozzle ring on the main body, wherein the high-pressure air cap has at least one central opening with a second diameter, and wherein the second diameter is smaller than the first diameter of the low-pressure air cap.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0067] The disclosure will be discussed in more detail below by way of example on the basis of 18 figures, in which:
[0068] FIG. 1 shows a part, shown partially in an exploded view, of a spray gun with air distribution ring according to the prior art disclosed in the Chinese utility model specification ZL 2014 2 0431026.7;
[0069] FIG. 2 shows a plan view of a head region of a main body of a spray gun according to the prior art disclosed in the cited Chinese utility model specification;
[0070] FIG. 3 shows a sectional view of a head region of a spray gun according to the prior art disclosed in the Chinese utility model specification ZL 2016 2 0911120.1;
[0071] FIG. 4 shows an exploded view of an exemplary embodiment of a spray gun according to the disclosure;
[0072] FIG. 5 shows a sectional view of an exemplary embodiment of a main body according to the disclosure for a spray gun;
[0073] FIG. 6 shows a sectional view of the head region of an exemplary embodiment of a main body according to the disclosure for a spray gun;
[0074] FIG. 7 shows a perspective view of the head region of an exemplary embodiment of a main body according to the disclosure for a spray gun;
[0075] FIG. 8 shows a perspective view of an exemplary embodiment of a nozzle for use in an exemplary embodiment of a spray gun according to the disclosure or with an exemplary embodiment of a main body according to the disclosure for a spray gun;
[0076] FIG. 9 shows a perspective view of the exemplary embodiment of a nozzle from FIG. 8 from another side;
[0077] FIG. 10 shows a view from the rear of the exemplary embodiment of a nozzle from FIG. 8;
[0078] FIG. 11 shows a sectional view of the exemplary embodiment of a nozzle from FIG. 8;
[0079] FIG. 12 shows a sectional view of the head region of an exemplary embodiment of a spray gun according to the disclosure or of an exemplary embodiment of a main body according to the disclosure with the exemplary embodiment of a nozzle from FIG. 8;
[0080] FIG. 13 shows a perspective view of a second exemplary embodiment of a nozzle for use in an exemplary embodiment of a spray gun according to the disclosure or with an exemplary embodiment of a main body according to the disclosure for a spray gun;
[0081] FIG. 14 shows a perspective view of the exemplary embodiment of a nozzle from FIG. 13 from another side;
[0082] FIG. 15 shows a view from the rear of the exemplary embodiment of a nozzle from FIG. 13;
[0083] FIG. 16 shows a sectional view of the exemplary embodiment of a nozzle from FIG. 13;
[0084] FIG. 17 shows a sectional view of the head region of an exemplary embodiment of a spray gun according to the disclosure or of an exemplary embodiment of a main body according to the disclosure with the exemplary embodiment of a nozzle from FIG. 13; and
[0085] FIG. 18 shows a perspective view of a part of an exemplary embodiment of a main body according to the disclosure.
DETAILED DESCRIPTION
[0086] The part of a spray gun 100, in particular a paint spray gun, according to the prior art which is shown in FIG. 1 has a main body 102 with various attachment parts. The figure shows an air distribution ring 104, which can be arranged on the head region 103 of the main body 102. For this purpose, the air distribution ring 104 has at least one, in the present example two, holding pins 106a and 106b, which are inserted into two blind holes 108a and 108b which correspond with the holding pins 106a and 106b and which are illustrated in FIG. 2, in order to fasten the air distribution ring 104 to the gun head or to the head region 103 of the main body 102 such that the wall 107 of the air distribution ring 104 bears sealingly against the front surface 110 of the head region 103 of the main body 102, as shown in FIG. 3. The head region 103 shown in FIG. 3 is disclosed in the Chinese utility model specification ZL 2016 2 0911120.1. An atomization air outlet opening 114 in the front surface 110 of the head region 103 of the main body 102 is in this case situated within the wall 107 of the air distribution ring 104. Atomization air flows out of the atomization air outlet opening 114 into an inner air distribution chamber 116, which is formed by the air distribution ring 104 and the main body 102. A horn air outlet opening 112 in the front surface 110 of the head region 103 of the main body 102 lies outside the wall 107 of the air distribution ring 104. Horn air flows out of the horn air outlet opening 112 into an outer air distribution chamber 118 of the air distribution ring 104.
[0087] On a surface within the wall 107, the air distribution ring 104 has, distributed over its circumference, multiple passages 120 through which the atomization air flows out of the inner air distribution chamber 116. From the passages 120, the atomization air flows to a plate 124 which is arranged on the paint nozzle 122 as a single piece and which bears sealingly against a wall 109 of the air distribution ring 104, wherein the wall 109 is arranged on that side of the air distribution ring 104 which is averted from the front surface 110 of the head region 103 of the main body 102. The plate 124 has, distributed over its circumference, a multiplicity of passage bores 126. The air that has flowed through the passage bores 126 subsequently flows through a ring-shaped gap 130 between the central opening of the air cap 132 and the front end of the paint nozzle 122, which may be designed in the form of a spigot.
[0088] The outer air distribution chamber 118 of the air distribution ring 104 forms, together with an outer wall 134 on the head region 103 of the main body 102, a gap through which the horn air flows out of the outer air distribution chamber 118. From there, the air flows into the horn air feed channels in the air cap 132 and subsequently into the horn air bores 136, out of the openings of which the air emerges.
[0089] FIG. 4 shows an exploded view of an exemplary embodiment of a spray gun 1 according to the disclosure, or of an exemplary embodiment of a main body 2 according to the disclosure with attachment parts. The spray gun 1 may have a cup 3 for receiving and dispensing the material for spraying, wherein the cup comprises a cover 3b with a valve plug 3a, a cup body 3c and a strainer insert 3d. The spray gun 1 may furthermore comprise a material flow rate regulating device 11, an air micrometer 13, a fan control 19, a trigger system 7 composed of trigger and fastening means, and an air attachment, which may be designed as a standard attachment 4a or as a rotary joint attachment 4b. On the head region 6 of the main body 2, there can be arranged a nozzle arrangement composed of a nozzle 24, which may comprise a material nozzle 40. The nozzle arrangement may furthermore comprise an air cap 76, which can be fastened, in particular screwed, to the head region 6 by means of an air nozzle ring 74. The head region 6, the nozzle 24 and the air cap 76 with air nozzle ring 74 are, in the present case, arranged or arrangeable coaxially along an axis Z, which in the present case constitutes the above-stated central or longitudinal axis of the head region 6 of the main body 2, the central or longitudinal axis of the material nozzle 40, the central or longitudinal axis of the upper part of the main body 2, and the central or longitudinal axis of a receiving opening for receiving the material flow rate regulating device 11.
[0090] FIG. 5 illustrates a sectional view of the exemplary embodiment of a main body 2 according to the disclosure for a spray gun from FIG. 4, wherein the section has been taken from top to bottom through the axis Z from FIG. 4. The main body 2 has a multiplicity of bores; in the upper part of the main body 2, in particular a multiplicity of bores along an axis Z, which in the present case constitutes the above-stated central or longitudinal axis of the head region 6 of the main body 2. In the present exemplary embodiment, said axis is identical to the central or longitudinal axis of the material nozzle 40, which can be arranged in or on the main body 2, from FIG. 4, and identical to the central or longitudinal axis of the upper part of the main body 2 and identical to the central or longitudinal axis of a receiving opening 82 for receiving a material flow rate regulating device 11, which is shown by way of example in FIG. 4.
[0091] Where it is described above that the front end of a wall is set back in relation to the front end of another wall along an axis, along an axis means the axis Z. As can be seen in FIG. 5, the middle wall 12 is clearly set back in relation to the outer wall 14. Here, front is to be regarded as the spraying direction or that side of the main body 2 on which the material nozzle 40 from FIG. 4 can be arranged, and rear is to be regarded as the opposite side or opposite direction, in this case the side with the receiving opening 82. The statement that the front end of the middle wall 12 is set back in relation to the front end of the outer wall 14 along an axis Z means that the front end of the outer wall 14 is further forward than the front end of the middle wall 12.
[0092] In the present exemplary embodiment, the inner wall 10 is set back only slightly in relation to the middle wall 12.
[0093] In FIG. 5, only a single atomization air channel 64 and one horn air channel 66, which intersects a second horn air channel, can be seen. The sectional view furthermore shows a part of a fan control air distribution chamber 68.
[0094] FIG. 6 shows a sectional view of a part of the exemplary embodiment of a main body 2 according to the disclosure for a spray gun 1, which is shown in another sectional view in FIG. 5. The section shown in FIG. 6 has again been taken through the axis Z from FIG. 4, but along a section plane which is perpendicular to the section plane used in FIG. 5. In the present FIG. 6, it can be seen that the inner wall 10 of the head region 6 of the main body 2 of the spray gun 1 is set back by a spacing d4 in relation to the middle wall 12 along the axis Z. The middle wall 12 is in turn set back by a spacing d3 in relation to the outer wall 14 along the axis Z. In other words, the outer wall 14 projects beyond the middle wall 12, which in turn projects beyond the inner wall 10. The inner wall 10 and the outer wall 12 delimit a first air distribution chamber 60, and the middle wall 12 and the outer wall 14 delimit a second air distribution chamber 62. Towards the front, that is to say in the spraying direction, the air distribution chambers 60 and 62 are open, whereas, towards the rear, they are at least regionally delimited by a first front surface 16 and a second front surface 18 respectively. In the present exemplary embodiment, a groove 19 is formed into the second front surface 18, the base surface of which groove regionally delimits the air distribution chamber 62 to the rear instead of the second front surface 18. The air distribution chamber 62 is thus delimited towards the rear regionally by the second front surface 18 and regionally by the base surface of the groove 19. The spacing d5, that is to say the depth of the groove 19, that is to say the spacing between the second front surface 18 and the base surface of the groove 19 may for example amount to approximately 1.5 mm to 3.0 mm. The spacing d1 between the first front surface 16 and the front end of the outer wall 14 preferably amounts to between 8 mm and 12 mm, particularly preferably between 9 mm and 11 mm. The spacing d2 between the second front surface 18 and the front end of the outer wall 14 preferably amounts to between 4 mm and 6 mm. The middle wall 12 is in the present case set back by a spacing d3, which preferably amounts to approximately 2 mm to 4 mm, in relation to the outer wall 14 along the axis Z. The inner wall 10 is preferably set back only by 0.1 mm to 1.0 mm in relation to the middle wall 12. This is the spacing d4. The exemplary embodiment of a head region 6 of a main body according to the disclosure shown in FIG. 6 has a counterpart sealing surface 84 for a nozzle seal which is not shown in FIG. 6. The spacing d6 of said counterpart sealing surface 84 to the first front surface 16 preferably amounts to approximately 1.5 mm to 3.0 mm. The first front surface 16 is set back in relation to the second front surface 18 along the axis Z. In the present exemplary embodiment, the spacing d7 by which the front surface 16 is set back in relation to the second front surface 18 amounts to approximately 4 mm to 6 mm. The stated dimensions or dimension combinations have, in spraying tests, proven to be advantageous for good atomization quality.
[0095] FIG. 7 shows a perspective view of a part of the exemplary embodiment of a main body 2 according to the disclosure from FIG. 5 and FIG. 6. In particular, the groove 19 in the second front surface 18 can be clearly seen here. The width of the groove 19 has approximately the same width as the second front surface 18. The width of the groove 19 or of the second front surface 18 is in this case to be understood in each case to mean the extent in a radial direction of the head region 6 of the main body 2, or else the spacing between the middle wall 12 and outer wall 14 in a radial direction. In a circumferential direction, the groove 19 extends over approximately 50% of the circumference of the second front surface 18, that is to say in the present case over approximately 180. In the present exemplary embodiment, the inner wall 10, the middle wall 12 and the outer wall 14 are in each case of circular design and arranged concentrically with respect to one another and coaxially with respect to the axis Z from the previous drawings. The axis Z runs through the axis of rotation of the walls, and the walls run parallel to the axis Z.
[0096] In the present case, the inner wall 10 has an internal thread 70 into which a nozzle not shown in FIG. 7, in particular a material nozzle, which is commonly also referred to as paint nozzle, can be screwed. In the present case, the outer wall 14 has an external thread 72, by means of which an air nozzle ring which is not shown in FIG. 7 and which has an air cap can be screwed onto the head region 6 of the main body 2. In the present case, the middle wall 12 has no thread. It is however conceivable that the middle wall 12 may also have an internal or external thread. It is furthermore conceivable for the outer wall 14 to have an internal thread for the screwing-in of a component, in particular of an air cap, and for the inner wall 10 to have an external thread for the screwing-on of a component, in particular of a nozzle.
[0097] In the present case, the first front surface 16 has two inner air outlet openings 20a and 20b, and in the present case, the second front surface 18 has two outer air outlet openings 22a and 22b. The diameter of the air outlet openings 20a, 20b, 22a and 22b corresponds approximately to the width of the front surfaces 16, 18 or of the groove 19 into which they are formed. The available space can thus be utilized for a maximum throughput of air.
[0098] FIG. 8 shows a perspective view of an exemplary embodiment of a nozzle 24 for use in an exemplary embodiment of a spray gun according to the disclosure or with an exemplary embodiment of a main body according to the disclosure for a spray gun or else for use in a method according to the disclosure. The nozzle 24 may have at least one material nozzle 40 with a material outlet opening 28 and with a portion for the engagement of a tool, in the present case an external hexagonal profile 41, and a disc element 32 with a front surface 34 and with a conical surface 35. In the present case, the front surface 34 has multiple, preferably 7 to 9, passage openings 36 distributed over the circumference. Material nozzle 40 and disc element 32 are preferably formed as a single piece. Arranged thereon, preferably captively arranged thereon, particularly preferably pressed thereon, is a first impingement disc 30. Arranged on this in turn, preferably arranged on this as a single piece, is a second impingement disc 42, which can be seen in FIG. 9. Said second impingement disc is arranged on that side of the first impingement disc 30 which is averted from the material outlet opening 28. Like the first impingement disc 30, the second impingement disc 42 is also of ring-shaped design with an inner and an outer circumference. In a radial direction, the inner circumference of the second impingement disc 42 does not extend to the external thread 46 of the material nozzle 40, such that a gap exists between the inner circumference of the second impingement disc 42 and the external thread 46 of the material nozzle 40. Along an axis, that is to say along the central or longitudinal axis of the nozzle 24, the second impingement disc 42 is spaced apart from the passage openings 36. In a radial direction, the second impingement disc 42 almost fully overlaps the passage openings 36, as can be clearly seen in FIG. 10. Also visible in FIG. 10 are the material outlet opening 28 and the impingement surface 30a of the first impingement disc 30. It is preferable if the disc element 32 has, on its side averted from the material outlet opening 28, an incision or a groove in which the passage openings 36 are arranged. In this way, the spacing between that side of the disc element 32 which is averted from the material outlet opening 28 and that side of the second impingement disc 42 which faces toward said side increases, and the air that flows into said region has a greater volume to distribute in.
[0099] FIG. 11 shows the construction of the nozzle 24 in a sectional view. It can be seen that the material nozzle 40 with its material outlet opening 28 and the disc element 32 are formed as a single piece. At its side averted from the material outlet opening 28, the disc element 32 has an encircling groove 33 which permits or facilitates the pressing of the first impingement disc 30 onto the disc element 32. The first impingement disc 30 has an inner circumference and an outer circumference, wherein the outer circumference of the first impingement disc 30 is greater than the outer circumference of the disc element 32. The inner circumference of the first impingement disc 30 extends approximately to the passage openings 36 of the disc element 32. The second impingement disc 42 is arranged as a single piece on the first impingement disc 30. A collar 43 may be arranged in between. The first impingement disc 30, the second impingement disc 42 and possibly the collar 43 form, in the present case, a Z shape. The first impingement disc 30 may have a recess on its side facing towards the material outlet opening 28, in particular in the region of the inner circumference, such that a stepped form is realized which can form the contact region between the first impingement disc 30 and disc element 32. In the present case, the disc element 32 likewise has a step on its side averted from the material outlet opening 28, in particular in the region of the outer circumference, which step forms the contact region between the first impingement disc 30 and disc element 32.
[0100] In the present case, the material nozzle 40 is equipped with an air guide disc 38, which may likewise be captively connected to, in particular pressed onto, the material nozzle 40. Furthermore, the present nozzle 24 has a nozzle seal 44, the purpose of which will be discussed further below. The nozzle seal 44 is preferably composed of plastic and is preferably exchangeably connected to the material nozzle 40. The external thread 46 of the material nozzle 40 is also indicated in FIG. 11.
[0101] FIG. 12 shows a sectional view of the head region 6 of an exemplary embodiment of a spray gun according to the disclosure or of an exemplary embodiment of a main body according to the disclosure with the exemplary embodiment of a nozzle 24 from FIG. 8 to FIG. 11 in the assembled state. The nozzle 24, which in the present case is provided as a unit composed of material nozzle 40 with disc element 32, first impingement disc 30, second impingement disc 42, air guide disc 38 and nozzle seal 44, is screwed by means of the thread described above into the main body or into the head region thereof. Here, the stop is formed by the first impingement disc 30, in particular the impingement surface 30a thereof, and the middle wall 12 of the head region 6 of the main body. The impingement surface 30a of the first impingement disc 30 acts in this case as sealing surface, and the middle wall 12, in particular the front end of the middle wall 12, acts as counterpart sealing surface, against which the impingement surface 30a sealingly bears. Alternatively or in addition, it is also possible for the outer surface of the second impingement disc 42 or the outer surface of the collar 43 between first impingement disc 30 and second impingement disc 42 to bear sealingly against an inner surface of the middle wall 12.
[0102] When nozzle 24 has been screwed in, the nozzle seal 44 is pressed against a counterpart sealing surface 84, which is shown in FIG. 6, and seals off the material-guiding region of the spray gun, in particular the transition region between paint channel in the main body and hollow portion of the material nozzle 40 for guiding through the material for spraying, with respect to the air-guiding region of the spray gun.
[0103] In the installed state, the first impingement disc 30 forms, with the outer wall 14, a gap 86 which preferably constitutes a ring-shaped gap with a substantially constant width. The second impingement disc 42 forms, with the inner wall 10, a further gap 88, which likewise preferably constitutes a ring-shaped gap with a substantially constant width.
[0104] By means of the abovementioned thread, the air nozzle ring 74 can be arranged on the head region 6 of the main body. The air cap 78 is arranged in the air nozzle ring 74, wherein the air cap 78 is fixed in a first direction by means of a flange 90 which bears against a projection on the inner surface of the air nozzle ring 74. In the opposite direction, the air cap 78 is delimited by means of a securing ring 89, which lies in a groove 91 in the air cap 78 and in a recess in the inner surface of the air nozzle ring 74. Merely in order to be more clearly identified, the securing ring 89 is, in the present FIG. 12, illustrated outside the groove 91, wherein it is also not necessary for the securing ring 89 to be situated entirely in the groove 91. For example, the securing ring 89 may be of polygonal design, such that it lies only regionally in the circular groove 91.
[0105] As can be seen in FIG. 7, in the present exemplary embodiment of the main body according to the disclosure, the first front surface 16 between inner wall 10 and middle wall 12 and the second front surface 18 between middle wall 12 and outer wall 14 have in each case two air outlet openings 20a and 20b or 22a and 22b respectively. Referring again to FIG. 12, it can be seen that the air flowing out of the two inner air outlet openings 20a and 20b between inner wall 10 and middle wall 12 firstly impinges on the second impingement disc 42. Owing to the constriction in the form of the gap 88, the air distributes over the circumference of the air distribution chamber between inner wall 10 and middle wall 12. The air flows through the gap 88 and is thereby throttled before it flows through the passage openings 36 of the disc element 32. The air, which in a certain way emerges in punctiform fashion from the passage openings 36, impinges on the air guide element 38, whereby the air is distributed more areally, is homogenized and is throttled again slightly owing to the slight constriction between air guide element 38 and inner surface of the air cap 78. From the air cap chamber 80 between air cap 78 and material nozzle 40, the air then flows through a gap, in particular a ring-shaped gap, which forms as a result of the front end of the material nozzle 40 projecting from the inside into the central opening 79 in the air cap 78. The material for spraying which flows from a material feed device through the paint channel in the main body of the spray gun and the hollow portion of the material nozzle 40 is atomized by the air flowing out of the gap, whereby the so-called spray jet is formed. The air with the profile described immediately above is thus referred to as atomization air. The two inner air outlet openings 20a and 20b between inner wall 10 and middle wall 12 may be referred to as atomization air outlet openings, the air channels situated therebehind may be referred to as atomization air channels, and the air distribution chamber which is delimited by the inner wall 10 and the middle wall 12 may be referred to as atomization air distribution chamber. The region flowed through by the atomization air may be referred to as atomization air region.
[0106] The air flowing out of the two outer air outlet openings 22a and 22b, which are duly present in the exemplary embodiment of the main body according to the disclosure shown in FIG. 12 but can be seen particularly clearly in FIG. 7, firstly impinges on the first impingement disc 30. Owing to the constriction in the form of the gap 86, the air distributes over the circumference of the air distribution chamber between middle wall 12 and outer wall 14. The air flows through the gap 86 and is thereby throttled. The air advantageously subsequently flows into an intermediate chamber 92 and into the horn air feed channels 78a in the horns of the air cap 78. From here, the air flows out of the horn air bores 78b and impinges on the abovementioned spray jet and deforms the latter. In particular, the so-called horn air flowing out of the horn air bores 78b in the diametrically oppositely situated horns of the air cap 78 compresses the spray jet, which originally has a circular cross section, at two opposite sides, whereby a so-called wide jet is formed. The flow rate of the horn air flowing out of the horn air bores 78b, or even the flow rate of the air flowing out of the outer air outlet openings 22a and 22b, which can be referred to as horn air outlet openings, can be set by means of a fan control 9 shown by way of example in FIG. 4. If the horn air is reduced to zero or approximately zero, the spray gun generates a so-called round jet with a circular cross section. The air channels behind the so-called horn air outlet openings may be referred to as horn air channels, the air distribution chamber that is delimited by the middle wall 12 and the outer wall 14 is referred to as horn air distribution chamber, and the region flowed through by the horn air is referred to as horn air region. For the sealing of the horn air region with respect to the surroundings, a sealing element 87 may be provided between air nozzle ring 74 and head region 6.
[0107] So-called control openings 79a may be formed into the front surface of the air cap 78, radially outside the central opening 79. The air emerging from the control openings 79a influences the horn air, in particular weakens the impingement of the horn air on the spray jet. Furthermore, the so-called control air protects the air cap 78 against contamination, by carrying paint droplets away from the air cap 78. It furthermore contributes to the further atomization of the spray jet. The control air also acts on the round jet and causes a slight pre-deformation and, in this case, too, additional atomization.
[0108] As can be clearly seen in FIG. 12, the separation, in particular the sealing, between atomization air region and horn air region is realized by means of the middle wall 12, the first impingement disc 30, the disc element 32 and by means of the air cap 78, in particular by means of a preferably encircling web 78c of the air cap 78. In the present case, the web 78c has a conical region which bears against the conical surface 35 of the disc element 32. Centring of the air cap 78 is also realized in this way, whereby it is ensured that the air cap 78 and the material nozzle 40 are arranged concentrically with respect to one another, and the above-stated gap, in particular the ring-shaped gap, between the front end of the material nozzle 40 and the air cap 78 for the outlet of the atomization air has a constant width.
[0109] It is clear that, owing to the particular design of the main body according to the disclosure and of the spray gun according to the disclosure, no additional sealing element is required for sealing between the atomization air region and horn air region. Owing to the front end of the middle wall 12 being set back in relation to the front end of the outer wall 14, the middle wall 12, which is of significance for the sealing between atomization air region and horn air region, of the main body according to the disclosure is well protected against damage even when a nozzle 24 has been unscrewed. Furthermore, by means of this design, the head region 6 of the main body according to the disclosure offers space for the first impingement disc 30, which thus does not project beyond the outer wall 14. The gun head can thus be of very compact design.
[0110] The nozzle 24 shown in FIGS. 8 to 12 is preferably a low-pressure or HVLP nozzle, or a nozzle for use in a low-pressure or HVLP nozzle arrangement, in particular for use in a method according to the disclosure for converting a spray gun, in particular a paint spray gun.
[0111] FIG. 13 shows a perspective view of a second exemplary embodiment of a nozzle for use in an exemplary embodiment of a spray gun according to the disclosure or with an exemplary embodiment of a main body according to the disclosure for a spray gun or else for use in a method according to the disclosure. In relation to the first exemplary embodiment shown in FIGS. 8 to 12, the present nozzle 50 has no air guide disc, and the disc element 32 has a greater number of passage openings 36 in the front surface 34. The nozzle 50 otherwise also has a material nozzle 40 with a material outlet opening 28, and the disc element 32 has a conical surface 35. The disc element 32 preferably has, on its side averted from the material outlet opening 28, an incision or a groove in which the passage openings 36 are arranged. Thus, in the installed state of the nozzle 50, the spacing between that side of the disc element 32 which is averted from the material outlet opening 28 and the first front surface 16 of the head region 6 of the main body 2 increases, and the air that flows into said region has a greater volume to distribute in.
[0112] It can be seen for the first time in FIG. 14 that the first impingement disc 31 of the nozzle 50 is designed differently than the first impingement disc 30 of the nozzle 24 described above. The nozzle 50 has no second impingement disc, and instead has an inner collar 52 and an outer collar 53 with an interposed impingement surface 31a.
[0113] In FIG. 15, which shows a view of the nozzle 50 from the rear, it is clear that the passage openings 36 are completely exposed, that is to say are not covered or projected over by other components of the nozzle 50. The disc element 32 of the nozzle 50 preferably has a greater number of passage openings 36, in particular between 10 and 14.
[0114] The exposed passage openings 36 can also be seen in FIG. 16, which is a sectional view of the nozzle 50. The material nozzle 40 with disc element 32 arranged as a single piece and preferably exchangeably arranged nozzle seal 44 is substantially identical to the material nozzle 40 with disc element 32 arranged as a single piece and preferably exchangeably arranged nozzle seal 44 of the above-described nozzle 24. The above statements relating to these components apply correspondingly to the nozzle 50. The first impingement disc 31 with inner collar 52, outer collar 53 and interposed impingement surface 31a differs from the first impingement disc 30 of the above-described nozzle 24.
[0115] FIG. 17 shows a sectional view of the head region 6 of an exemplary embodiment of a spray gun according to the disclosure or of an exemplary embodiment of a main body according to the disclosure with the exemplary embodiment of a nozzle 50 from FIGS. 13 to 16. The main body is the exemplary embodiment shown in FIG. 12. In particular, the head region 6 is of identical design, for which reason reference can be made to the above statements relating to this. It can be seen that the gap 86 between outer wall 14 and first impingement disc 31 is narrower than the gap 86 from FIG. 12, which shows the head region 6, equipped with the above-described nozzle 24, of the main body. Since this is the same main body with the same dimensions, in particular with the same internal diameter of the outer wall 14, it is clear that the first impingement disc 31 of the nozzle 50 has a greater outer diameter than the first impingement disc 30 of the nozzle 24. The rest of the statements relating to the arrangement shown in FIG. 12 may also apply to the arrangement shown in FIG. 17.
[0116] Owing to the absent second impingement disc and absent air guide disc in the case of the nozzle 50 in relation to the nozzle 24, the atomization air is throttled less intensely in the arrangement shown in FIG. 17, that is to say in the case of the nozzle 50 being used, than in the case of the arrangement shown in FIG. 12, that is to say in the case of the nozzle 24 being used. In this way, the nozzle internal pressure, that is to say in particular the pressure in the air cap chamber 81 between air cap 78 and material nozzle 40 in the case of the nozzle 50 being used is greater than the nozzle internal pressure, that is to say in particular the pressure in the air cap chamber 80 shown in FIG. 12 between air cap 78 and material nozzle 40, in the case of the nozzle 24 being used.
[0117] The nozzle 50 shown in FIGS. 13 to 17 is preferably a high-pressure or compliant nozzle, or a nozzle for use in a high-pressure or compliant nozzle arrangement, in particular for use in a method according to the disclosure for converting a spray gun, in particular a paint spray gun, with a first nozzle internal pressure into a spray gun, in particular a paint spray gun, with a second nozzle internal pressure.
[0118] FIG. 18 shows a perspective view of a part of an exemplary embodiment of a main body according to the disclosure, specifically of the region in which a fan control 9 shown by way of example in FIG. 4 can be arranged. In particular, in FIG. 18, the interior of the fan control air distribution chamber 68 can be at least partially seen. As described above, the main body 2 according to the disclosure may, on the head region 6, have in each case two atomization air outlet openings 20a, 20b and two horn air outlet openings 22a, 22b, as can be seen in FIG. 7. In the head region 6, the two atomization air outlet openings 20a, 20b are spaced apart from one another, as are the two horn air outlet openings 22a, 22b. The atomization air channels situated behind the two atomization air outlet openings 20a, 20b, that is to say the air channels which end in the form of the atomization air outlet openings 20a, 20b, extend into the fan control air distribution chamber 68, converge along their path into the fan control air distribution chamber 68, and meet at the latest at the point of intersection with a wall of the fan control air distribution chamber 68. The fan control air distribution chamber 68 thus has only a single atomization air channel mouth 20c. The horn air channels situated behind the two horn air outlet openings 22a, 22b, that is to say the air channels which end in the form of the horn air outlet openings 22a, 22b, also extend into the fan control air distribution chamber 68, converge on their path into the fan control air distribution chamber 68, and meet at the latest at the point of intersection with a wall of the fan control air distribution chamber 68. The fan control air distribution chamber 68 thus also has only a single horn air channel mouth 22c.
[0119] The outer contours of the atomization air channel mouth 20c and of the horn air channel mouth 22c in the fan control air distribution chamber 68 may have the outer contour of a horizontal 8. If the two atomization air channels and the two horn air channels in each case completely overlap at the inlet into the fan control air distribution chamber 68, the atomization air channel mouth 20c has substantially the same cross-sectional shape as at least one of the atomization air outlet openings 20a and 20b, and the horn air channel mouth 22c has substantially the same cross-sectional shape as one of the horn air outlet openings 22a, 22b.
[0120] Various fan controls are known from the prior art, for example from EP 0 706 832 B1 or EP 2 451 586 B1. For the present main body according to the disclosure, use may be made of any type of fan controls. It is however preferable for the fan control air distribution chamber 68 to have a first chamber portion and a second chamber portion, wherein the second chamber portion has a greater diameter than the first chamber portion. The horn air channels of the main body 2 open into the first chamber portion, that is to say the horn air channel mouth 22c is situated in the first chamber portion. The atomization air channels of the main body 2 open into the second chamber portion, that is to say the atomization air channel mouth 20c is situated in the second chamber portion. The portions form a step against which a plate of a fan control can bear in order to close the first chamber portion and thus prevent the feed of air into the horn air channel mouth 22c and thus into the horn air channels. In this case, during the operation of the spray gun, only the atomization air channel mouth 20c and thus the atomization air channels are supplied with air. The spray gun generates a round jet with a substantially circular cross section, because no horn air acts laterally on the spray jet. By means of a rotary mechanism, for example, the plate of the fan control can be moved preferably in continuously variable fashion away from the step between first and second chamber portion of the fan control air distribution chamber 68, such that the plate permits the feed of air to the first chamber portion and thus to the horn air channel mouth 22c and to the horn air channels in the main body 2. The further the plate is moved away from the step, the more air can flow through the horn air channels and thus out of the horn air bores, and the greater the extent to which the spray jet is laterally compressed, whereby an ever narrower wide jet is generated.
[0121] It is finally pointed out that the described exemplary embodiments describe only a limited selection of design possibilities, and thus do not constitute a limitation of the present disclosure.
