Output device for outputting a liquid jet surrounded in a jacket-like manner by an air flow

Abstract

The invention relates to an output device (10) for outputting a liquid jet (18) which is surrounded in a jacket-like manner by an air flow and widens in a fan-like manner in a jet plane (16). The dispensing device (10) comprises: a jet generating part (12) having a flat jet nozzle (30) for generating the liquid jet (18); and an air enveloping part (14) for enveloping the liquid jet (18) with an air flow. The air enveloping part (14) comprises: a receiving portion (66) for receiving the liquid jet (18); and an output portion (68) for outputting the liquid jet (18) and the air flow enveloping said liquid jet. The receiving portion (66) is fluidically connected to at least one air intake opening (70, 72). The output portion (68) extends as far as an outlet opening (64) and widens in a fan-shaped manner in the jet plane (16). The distance, measured in centimetres, of the outlet opening (64) from the nozzle outflow opening of the flat jet nozzle (30) is at least 0.16 times a predetermined percentage increase in the cleaning width plus a fixed value of 9 cm, wherein the percentage increase in the cleaning width relates to the cleaning width which can be achieved, with the same cleaning intensity, by the flat jet nozzle (30) without the air enveloping part (14).

Description

[0001] Dispensing device for discharging a liquid jet surrounded by an air flow

[0002] The invention relates to a dispensing device for dispensing a liquid jet which is surrounded by an air flow and widens in a fan shape in a jet plane, wherein the dispensing device comprises a jet generation part with a flat jet nozzle for generating the liquid jet and an air enveloping part for enveloping the liquid jet with an air flow, wherein the air enveloping part has a through-channel which has a receiving section for receiving the liquid jet and a dispensing section for dispensing the liquid jet and the air flow surrounding it, wherein the receiving section is in flow connection with at least one air intake opening of the dispensing device and the dispensing section extends to an outlet opening and widens in a fan shape in the jet plane.

[0003] Jet-generating parts with a flat jet nozzle for generating a liquid jet that expands fan-shaped in a jet plane are used, for example, as accessories for pressure cleaning devices, particularly for high-pressure cleaning devices, to cover a surface to be cleaned with a fan-shaped liquid jet. The jet-generating parts can be designed, for example, as a jet pipe with an integrated flat jet nozzle. Pressurized water, for example, can be used as the liquid. Such flat jet nozzles are known from WO 2014 / 090333 A1.

[0004] The fan-shaped liquid jet emerging from the flat jet nozzle interacts with the ambient air on its way to the surface to be cleaned. This slows down the liquid jet and reduces its compactness, thus impairing the achievable cleaning intensity. To counteract this effect, JP 2004223409 A proposes a dispensing device in which, in addition to a jet-generating part in the form of a supply pipe carrying a flat jet nozzle at its free end, an air-enveloping part is used to envelop the liquid jet with an air flow, wherein the air flow surrounds the liquid jet provided by the flat jet nozzle in a jacket-like manner. The air-enveloping part has a through-channel with a receiving section and a dispensing section.The intake section receives the liquid jet emanating from the flat jet nozzle and is in fluid communication with several air intake openings. The output section extends from the intake section to an outlet opening of the air enclosure and widens in the jet plane as it approaches the outlet opening. Under the action of the liquid jet, air is drawn into the passageway via the air intake openings, forming an air jacket that envelops the liquid jet and is discharged together with the liquid jet through the outlet opening. The air jacket surrounding the fan-shaped expanding liquid jet reduces the interaction of the liquid jet with the ambient air.

[0005] By using the air-enveloping element when guiding the liquid jet along a surface to be cleaned, the dispensing device enables a wider area to be cleaned with the same cleaning intensity than is the case when using the flat jet nozzle without the air-enveloping element. This allows a larger cleaning width to be achieved across the surface to be cleaned. It would be helpful if the dispensing device could be designed in such a way that a predetermined percentage increase in the cleaning width could be achieved compared to the cleaning width that can be achieved with the same cleaning intensity using the same flat jet nozzle without the air-enveloping element.

[0006] The object of the present invention is therefore to further develop a dispensing device of the generic type in such a way that a predetermined percentage increase in the cleaning width can be achieved compared to the cleaning width that can be achieved with the same cleaning intensity using the same flat jet nozzle without the air enveloping part.

[0007] This object is achieved according to the invention in a dispensing device of the type mentioned at the outset in that the distance between the outlet opening of the air-enveloping part and the nozzle outlet opening of the flat jet nozzle, measured in centimeters, is at least 0.16 times a predetermined percentage increase in the cleaning width plus a fixed value of 9 cm, wherein the percentage increase in the cleaning width refers to the cleaning width that can be achieved with the flat jet nozzle without the air-enveloping part at the same cleaning intensity.

[0008] "Cleaning width" refers to the width of the strip of a surface to be cleaned, in which a specified cleaning intensity is achieved by passing the liquid jet once at a uniform speed along the surface while orientating the liquid jet perpendicular to the surface. The width of the strip is measured in the jet plane of the liquid jet. The specified cleaning intensity can, for example, be a specified percentage removal of a surface coating of a surface to be cleaned. The liquid jet can, for example, be passed along the surface to be cleaned at a relative speed of 10 cm / s, with the liquid jet directed perpendicularly to the surface. The specified percentage removal can, for example, be between 20% and 100%, in particular 50% of the surface coating.The surface to be cleaned could, for example, be a plastic sheet made of extruded polystyrene coated with emulsion paint. If the plastic sheet coated with emulsion paint is exposed to the liquid jet, the emulsion paint can be at least partially removed. When using black emulsion paint applied to a white plastic sheet made of extruded polystyrene, the cleaning intensity achievable using the liquid jet is reflected in a brightening of the surface of the plastic sheet exposed to the liquid jet. If the liquid jet is moved at a uniform speed relative to the plastic sheet and directed perpendicularly onto the plastic sheet, a strip-shaped, brightened surface area is formed. The width of the brightened surface area represents the achievable cleaning width.When using the dispensing device according to the invention, it is greater than the width of the striped surface area with the same brightening that can be achieved under the same conditions using the flat jet nozzle without the use of the air-enveloping part. The desired percentage increase in cleaning width determines the distance between the outlet opening of the air-enveloping part and the nozzle outlet opening of the flat jet nozzle required for this percentage increase. Specifically, the distance between the outlet opening of the air-enveloping part and the nozzle outlet opening of the flat jet nozzle required for the desired percentage increase in cleaning width is at least 0.16 times the desired percentage increase in cleaning width plus a fixed value of 9 cm.

[0009] The invention incorporates the insight that a specific linear relationship exists between a predetermined percentage increase in the cleaning width and the distance between the outlet opening of the air-enveloping part and the nozzle outlet opening of the flat jet nozzle required for this increase. At least for percentage increases in the range of 20% to 75%, a predetermined percentage increase in the cleaning width can be achieved by a distance between the outlet opening of the air-enveloping part and the nozzle outlet opening of the flat jet nozzle that, measured in centimeters, is at least 0.16 times the predetermined percentage increase in the cleaning width plus a fixed value of 9 cm. It should be noted that the distance can vary by ±5% due to manufacturing and measurement-related tolerances.As already mentioned, the percentage increase in cleaning width refers to the cleaning width that can be achieved with the same flat jet nozzle without the air-enveloping part at the same cleaning intensity. For example, if the dispensing device according to the invention is to achieve a 50% increase in cleaning width when the liquid jet is uniformly guided along the surface to be cleaned at a relative speed of 10 cm / s with the liquid jet aligned perpendicular to the surface, compared to the cleaning width that can be achieved with the same cleaning intensity using the flat jet nozzle of the dispensing device without the air-enveloping part, the dispensing device must be designed such that the distance between the outlet opening of the air-enveloping part and the nozzle outlet opening of the flat jet nozzle is at least 17 cm.

[0010] Preferably, the specified percentage increase in the cleaning width is 20% to 75%.

[0011] It is advantageous if the distance between the outlet opening of the air enclosure part and the nozzle outlet opening of the flat jet nozzle is a maximum of 0.16 times the specified percentage increase in the cleaning width plus an additional fixed value of no more than 13.5 cm, in particular 11 cm. This minimizes any impairment of the maximum achievable cleaning intensity and the handling of the dispensing device.

[0012] In an advantageous embodiment of the dispensing device according to the invention, the dispensing section, which widens fan-shaped in the jet plane, has an opening angle of 20° to 30°, in particular an opening angle of 25°, in the jet plane. Such opening angles make it possible to particularly effectively envelop the liquid jet within the dispensing section with air in order to protect the liquid jet from interference. The dispensing device according to the invention is preferably configured to dispense liquid at a pressure of 10 bar to 300 bar. The liquid pressure can in particular be 70 bar to 250 bar.

[0013] It is advantageous if the dispensing device is designed to dispense liquid with a volume flow of 300 l / h to 3,000 l / h, in particular with a volume flow of 300 l / h to 1,300 l / h, particularly preferably 400 l / h to 500 l / h, for example 490 l / h.

[0014] In a preferred embodiment of the dispensing device according to the invention, the flow cross-section of the receiving section of the through-channel decreases toward the dispensing section. This allows the air flowing into the receiving section via the at least one air intake opening to be accelerated.

[0015] It is advantageous if the discharge section is directly adjacent to the smallest flow cross-section of the intake section in the direction of fluid flow. The smallest flow cross-section of the intake section thus forms a throttle point in the through-channel, which is immediately followed by the discharge section, which widens in the jet plane. This increases the intake of air into the intake channel.

[0016] In order to keep flow losses of the sucked-in air particularly low, it is advantageous if the output section is connected tangentially to the intake section.

[0017] In a preferred embodiment of the invention, the smallest flow cross-section of the receiving section is arranged at a distance of 3 mm to 70 mm from the nozzle outlet opening of the flat jet nozzle, in particular at a distance of 20 mm to 40 mm, for example 29 mm. The height of the output section perpendicular to the jet plane is advantageously 1 mm to 6 mm. It has been shown that this results in only minimal impairment of the liquid jet, which expands fan-shaped in the jet plane perpendicular to the jet plane.

[0018] The height of the output section perpendicular to the jet plane can be constant over the entire length of the output section. Alternatively, the height of the output section perpendicular to the jet plane can decrease, at least in one longitudinal region, as it approaches the outlet opening of the air-enveloping part. For example, the output section can have a height of 6 mm in its inlet region, which decreases to 1 mm up to the outlet opening of the air-enveloping part.

[0019] The width of the outlet opening of the air enclosure part is advantageously 60 mm to 120 mm in the jet plane.

[0020] In a preferred embodiment of the dispensing device according to the invention, the flat jet nozzle is designed to dispense a liquid jet that widens in a fan shape at a jet angle of 20° to 30°, in particular at a jet angle of 23° to 27°, for example 25°.

[0021] The following description of an advantageous embodiment of the invention serves to explain it in more detail in conjunction with the drawings. They show:

[0022] Figure 1: a perspective view of a dispensing device for dispensing a liquid jet surrounded by an air flow and expanding fan-shaped in a jet plane, with a jet generation part and an air enveloping part;

[0023] Figure 2: a perspective view of the air envelope part of the dispensing device from Figure 1, viewed diagonally from the front; Figure 3: a perspective sectional view of the air envelope part of the dispensing device from Figure 1;

[0024] Figure 4: a partial sectional view of the dispensing device from Figure 1 in the jet plane of the liquid jet;

[0025] Figure 5: a graphic illustration of the distance between an outlet opening of the air-enveloping part and the nozzle outlet opening of a flat jet nozzle of the jet-generating part required to achieve a predeterminable percentage increase in a cleaning width.

[0026] Figures 1 to 4 schematically illustrate, by way of example, an advantageous embodiment of a dispensing device according to the invention for dispensing a liquid jet surrounded by a jacket-like air flow and expanding in a fan-shaped manner in a jet plane, and are designated overall by the reference numeral 10. The dispensing device 10 has a jet-generating part 12 and an air-enveloping part 14, which can be plugged together and locked together in a predetermined rotational position. With the aid of the jet-generating part 12, a liquid jet 18 can be generated that expands in a fan-shaped manner in a jet plane 16 and can be enveloped by a jacket-like air flow with the aid of the air-enveloping part 14. The jet plane 16 and the liquid jet 18 are shown in dash-dotted lines in Figure 3.

[0027] As is clear from Figures 1 and 4, the jet-generating part 12 has a jet pipe 20 with a first end region 22 and a second end region 24. A connecting element 26 is arranged at the first end region 22, with the aid of which the jet-generating part 12 can be detachably connected to a liquid supply part, which is known per se and therefore not shown in the drawing for the sake of clarity. In the illustrated embodiment, the connecting element 26 is designed as a bayonet connector 28. For example, a spray gun can be used as the liquid supply part, which is fluidly connected to a high-pressure cleaning device via a pressure hose.

[0028] At the second end region 24 of the jet pipe 20, a flat jet nozzle 30 is arranged in a rotationally fixed manner and is positively received by the jet pipe 20. Pressurized liquid, in particular a cleaning liquid, can be supplied to the jet generation part 12 via the liquid supply part (not shown in the drawing), which can be discharged by means of the flat jet nozzle 30 in the form of a liquid jet 18 expanding fan-shaped in the jet plane 16. Such flat jet nozzles are known to the person skilled in the art, for example, from WO 2014 / 090333 A1.

[0029] The jet pipe 20 is surrounded by a housing shell 32, which is formed by two half-shells that can be screwed together and forms a receptacle on its front side 38 facing the air-enveloping part 14, into which an end section of the air-enveloping part 14 facing the jet-generating part 12 can be inserted. The end section is designed in the form of a sleeve 40 and has two diametrically opposed locking hooks 42, 44 on its outer side, with the aid of which the jet-generating part 12 can be releasably locked to the air-enveloping part 14. This will be explained in more detail below.

[0030] The air enclosure part 14 has a housing 46 which adjoins the sleeve 40 in the direction away from the jet-generating part 12 and has a top wall 48, a bottom wall 50, an end wall 52 facing away from the jet-generating part 12, a rear wall 54 facing the jet-generating part 12, and two opposing, elastically deformable side walls 56, 58. The side walls 56, 58 are arranged between the top wall 48 and the bottom wall 50 and each extend from the end wall 52 to the rear wall 54. In the direction of the jet-generating part 12, a locking hook 42 or 44 is integrally connected to the side walls 56, 58, wherein the locking hooks 42, 44 extend through the rear wall 54. The sleeve 40 is integrally formed with the rear wall 54. The housing 46 of the air enclosure part 14 surrounds a through-channel 60 which extends from the free end 62 of the sleeve 40 to an outlet opening 64 of the air enclosure part 14.The outlet opening 64 is arranged on the end wall 52 of the housing 46.

[0031] As is particularly clear from Figures 3 and 4, the through-channel 60 has a receiving section 66 which receives the liquid jet 18 provided by the flat jet nozzle 30 and which is followed, in the flow direction of the liquid jet 18, by an output section which extends to the outlet opening 64 and continuously widens as it approaches the outlet opening 64 in the jet plane 16 defined by the liquid jet 18. The widening of the output section 68 ensures that the liquid jet 18 provided by the flat jet nozzle 30 is not impaired by the through-channel 60; rather, the liquid jet 18 maintains a distance from the wall of the through-channel 60 which remains essentially constant over the entire length of the output section 68.

[0032] At the level of the receiving section 66, the side walls 56, 58 of the housing 46 each have an air intake opening 70 or 72, to which an air intake duct 74 or 76 pointing into the interior of the housing 46 is connected.

[0033] Within the receiving section 66, a negative pressure is formed under the effect of the liquid jet 18, so that air is sucked into the receiving section 66 via the air intake openings 70, 72 and the adjoining air intake channels 74, 76, which air surrounds the liquid jet 18 in the circumferential direction in the form of an air jacket and is discharged together with the liquid jet 18 via the outlet opening 64. The liquid jet discharged by the dispensing device 10 is thus surrounded by a jacket-like air flow, which reduces the interaction of the liquid jet 18 with the ambient air, so that the deceleration of the liquid jet 18 can be reduced and the compactness of the liquid jet 18 is less impaired by the ambient air.

[0034] The output section 68 and an end region of the receiving section 66 immediately upstream of the output section 68 are defined by a stirring piece 78 which is surrounded by the housing 46 and is held by means of holding members 80 on the top wall 48 and the bottom wall 50 of the housing 46.

[0035] The side walls 56, 58 of the housing 46 extend from the end wall 52 to the rear wall 54. At a short distance from the end wall 52, the side walls 56, 58 each have a first retaining rib 82, which positively engages a complementarily designed retaining slot 84 in the top wall 58. In addition, at a short distance from the end wall 52, the side walls 56, 58 each have a second retaining rib (not shown in the drawing for clarity), which positively engages a complementarily designed retaining slot in the bottom wall 50.

[0036] Adjoining the air intake openings 70, 72 of the side walls 56, 58 in the direction of the jet-generating part 12 are each one of the previously mentioned locking hooks 42 and 44. The locking hooks 42, 44 each engage behind a locking projection 86, 88 arranged on the inside of the half-shells 34, 36 of the housing shell 32 of the jet-generating part 12, so that the air-enveloping part 14 can be locked to the jet-generating part 12. To release the locking connection when necessary and separate the air enclosure part 14 from the jet-generating part 12, the locking hooks 42, 44 each have a release element 90, 92 in a side wall region adjoining the air intake openings 70, 72 in the direction of the end wall 52. The release element 90, 92 is configured as a material thickening of the respective side wall 56, 58 and protrudes outwardly from the respective side wall 56, 58. This is clearly shown, for example, in Figure 4.

[0037] As already mentioned, the air enclosure part 14 can be plugged into the beam-generating part 12 and detachably locked. To establish the plug-in connection, the sleeve 40 of the air enclosure part 14 can be inserted into the housing shell 32 of the beam-generating part 12 and locked to the housing shell 32 by means of the locking projections 86, 88. When the sleeve 40 is inserted into the housing shell 32, the locking hooks 42, 44 automatically assume their locking position, in which they engage behind the respective associated locking projection 86, 88. If the user wishes to separate the air enclosure part 14 from the beam-generating part 12 again, they simply need to press the release elements 90, 92 against each other. This results in the side walls 56, 58 and with them also the locking hooks 42, 44 being moved into a release position in which they release the respective locking projection 86, 88.

[0038] As already mentioned, the discharge section 68 widens in the jet plane 16 of the liquid jet 18 as it approaches the outlet opening 64. The discharge section 68 has an opening angle α of 25°. The flat jet nozzle 30 has a nozzle contour and nozzle outlet opening designed such that the liquid forms a fan-shaped jet pattern upon leaving the flat jet nozzle 30, the jet angle β also being 25° in the exemplary embodiment.

[0039] As is clear from Figures 3 and 4, the flow cross-section of the end region of the receiving section 66 immediately upstream of the output section 68 decreases continuously in the direction of the output section 68, with the smallest flow cross-section of the receiving section 66 being arranged at a distance a of 29 mm in the illustrated embodiment. The output section 68 adjoins the smallest flow cross-section of the receiving section 66 in a tangentially continuous manner.

[0040] The dispensing device 10 is configured to dispense liquid at a pressure of 70 bar to 250 bar, with the volume flow of the liquid being approximately 300 l / h to approximately 1,800 l / h. The height of the dispensing section 68 perpendicular to the jet plane 16 is approximately 6 mm in the region of the dispensing section 68 immediately adjacent to the receiving section 66 and decreases to a value of approximately 2 mm in the end region of the dispensing section 68, which is immediately upstream of the outlet opening 64.

[0041] In the embodiment shown, the outlet opening 64 has a width of 80 mm in the jet plane 16, wherein the outlet opening of the air envelope part 14 in the embodiment shown is arranged at a distance A of 17 cm from the nozzle outlet opening of the flat jet nozzle 30.

[0042] The fan-shaped, widening liquid jet 18 can be directed onto a surface to clean the surface. If the liquid jet 18 is directed perpendicularly onto the surface to be cleaned and moved uniformly relative to the surface perpendicular to the jet plane, a strip-shaped surface area is formed that has been cleaned with a certain cleaning intensity, the width of which is referred to herein as the cleaning width. The use of the air-enveloping part 14 increases the cleaning width compared to the cleaning width that can be achieved with the same cleaning intensity using the flat jet nozzle 30 alone without the air-enveloping part 14. It has been recognized that a specific linear relationship exists between a predetermined percentage increase in the cleaning width and the distance A between the outlet opening 64 of the air-enveloping part 14 and the nozzle outlet opening of the flat jet nozzle 30 required for this increase.The distance A of the outlet opening 64 of the air-enveloping part 14 from the nozzle outlet opening of the flat jet nozzle 30 required for the desired percentage increase in the cleaning width, measured in centimeters, is at least 0.16 times the desired percentage increase in the cleaning width plus a fixed value of 9 cm.

[0043] To verify the aforementioned linear relationship between the percentage increase in cleaning width and the distance required for this increase, measurements were performed with several dispensing devices that differed from the dispensing device 10 described above only by different distances A. Depending on the dispensing device, the distances A ranged between 12.8 cm and 21.3 cm. For the measurements, a white plastic plate made of extruded polystyrene was coated with black emulsion paint.After the emulsion paint had hardened, in a first step, without using the air enclosure part 14, a fan-shaped, widening liquid jet was directed vertically from above onto the surface of the plastic plate coated with emulsion paint using only the flat jet nozzle 30. The plastic plate was moved at a constant speed of 10 cm / s perpendicular to the jet plane 16, so that a strip-shaped surface area formed on the plastic plate in which the emulsion paint was partially removed. The distance of the nozzle outlet opening of the flat jet nozzle 30 from the plastic plate was adjusted so that approximately 50% of the emulsion paint was removed. This was the case at a distance of 13.5 cm. The removal led to a brightening of the plastic plate in the form of a specific gray value, which indicates how bright the surface strip appears to the human eye.The width of the brightened surface area represents the cleaning width achieved by the flat jet nozzle 30 without the use of the air enclosure part 14 at a cleaning intensity corresponding to the detected brightening (gray value) of the surface area. The brightening thus represents a measure of the achieved cleaning intensity.

[0044] In a further step, the dispensing devices, which differed only in distance A from each other, were positioned one after the other above the plastic plate coated with emulsion paint. Again, the liquid jet 18 emanating from the respective dispensing device and expanding fan-shaped in the jet plane 16 was directed vertically from above onto the plastic plate, while the plate was moved perpendicular to the jet plane 16 at a constant speed of 10 cm / s relative to the dispensing device. The exposure to the liquid jet 18 created a striped surface area with a brightening effect on the plastic plate.The distance of the outlet opening of the dispensing devices from the plastic plate was individually adjusted for each dispensing device so that the same brightening and thus the same cleaning intensity was achieved as when using the flat jet nozzle 30 without the air enclosure part 14, i.e. the striped surface area had the same gray value as when using the flat jet nozzle 30 without the air enclosure part 14. Depending on the dispensing device, this was the case at distances of 1.5 cm to 3.3 cm. The measurements of the different dispensing devices therefore resulted in the same cleaning intensity as when measuring with the flat jet nozzle 30 alone without the air enclosure part 14. The pressure of the liquid supplied to the jet generation part 12 was 126 bar in all measurements, and the volume flow of the liquid was 490 l / h.The cleaning widths achieved with the individual output devices were each measured and compared with the cleaning width achieved when using the flat jet nozzle 30 without the air enclosure part 14 at the same cleaning intensity. The result of the measurements is illustrated in graph form in Figure 5. The graph shows the respective distance A of the measured output devices, i.e. the distance of the outlet opening 64 of the air enclosure part 14 from the nozzle outlet opening of the flat jet nozzle 30, as a function of the respectively measured percentage increase in the cleaning width achieved by means of the output devices compared to the cleaning width achieved with the flat jet nozzle 30 without the air enclosure part 14 at the same cleaning intensity.The graph clearly shows that the distance between the outlet opening 64 of the air-enveloping part 14 and the nozzle outlet opening of the flat jet nozzle 30 required for a predetermined percentage increase in the cleaning width is at least 0.16 times the predetermined percentage increase in the cleaning width plus a fixed value of 9 cm. Therefore, if a predetermined percentage increase in the cleaning width is to be achieved by means of the dispensing device 10 according to the invention compared to the cleaning width that can be achieved with the same cleaning intensity using the flat jet nozzle 30 without the air-enveloping part 14, it is only necessary to design the dispensing device 10 such that the distance A between the outlet opening 64 of the air-enveloping part 14 and the nozzle outlet opening of the flat jet nozzle 30 fulfills the aforementioned condition. This applies at least for increases in the cleaning width in the range of 20% to 75%.

Claims

P A T E N T A N S P R Ü C H E 1. Dispensing device for dispensing a liquid jet (18) surrounded by a jacket-like air flow and expanding fan-shaped in a jet plane (16), wherein the dispensing device (10) comprises a jet-generating part (12) with a flat jet nozzle (30) for generating the liquid jet (18) and an air-enveloping part (14) for enveloping the liquid jet (18) with an air flow, wherein the air-enveloping part (14) has a through-channel (60) which has a receiving section (66) for receiving the liquid jet (18) and a discharge section (68) for discharging the liquid jet (18) and the air flow surrounding it, wherein the receiving section (66) is in flow connection with at least one air intake opening (70, 72) of the dispensing device (10) and the discharge section (68) extends to an outlet opening (64) and fan-shaped in the beam plane (16), characterized in thatthat the distance (A) of the outlet opening (64) of the air-enveloping part (14) from the nozzle outlet opening of the flat jet nozzle (30), measured in centimeters, is at least 0.16 times a predetermined percentage increase in the cleaning width plus a fixed value of 9 cm, wherein the percentage increase in the cleaning width refers to the cleaning width that can be achieved with the flat jet nozzle (30) without the air-enveloping part (14) at the same cleaning intensity.

2. Dispensing device according to claim 1, characterized in that the predetermined percentage increase in the cleaning width is 20% to 75%.

3. Dispensing device according to claim 1 or 2, characterized in that the distance (A) of the outlet opening (64) of the air-enveloping part (14) from the nozzle outlet opening of the flat jet nozzle (30) measured in centimeters is a maximum of 0.16 times the specified percentage increase in the cleaning width plus a further fixed value of a maximum of 13.5 cm, in particular 11 cm.

4. Dispensing device according to one of the preceding claims, characterized in that the dispensing section (66) widening fan-shaped in the beam plane (16) has an opening angle of 20° to 30° in the beam plane (16).

5. Dispensing device according to claim 4, characterized in that the dispensing section (68) has an opening angle of 25° in the beam plane (16).

6. Dispensing device according to one of the preceding claims, characterized in that the dispensing device (10) is designed to dispense liquid at a pressure of 10 bar to 300 bar.

7. Dispensing device according to one of the preceding claims, characterized in that the dispensing device is designed to dispense liquid with a volume flow of 300 l / h to 3,000 l / h.

8. Dispensing device according to one of the preceding claims, characterized in that the flow cross-section of the receiving section (66) decreases in the direction of the dispensing section (68).

9. Dispensing device according to claim 8, characterized in that the dispensing section (68) is directly connected to the smallest flow cross-section of the receiving section (66) in the flow direction of the liquid.

10. Dispensing device according to claim 9, characterized in that the dispensing section (68) is tangentially connected to the receiving section (66).

11. Dispensing device according to claim 9 or 10, characterized in that the smallest flow cross-section of the receiving section (66) is arranged at a distance of 3 mm to 70 mm from the nozzle outlet opening of the flat jet nozzle (30).

12. Dispensing device according to one of the preceding claims, characterized in that the height of the dispensing section (68) perpendicular to the beam plane (16) is 1 mm to 6 mm.

13. Dispensing device according to one of the preceding claims, characterized in that the height of the dispensing section (68) perpendicular to the jet plane (16) is constant over the entire length of the dispensing section (68) or decreases at least in a longitudinal region of the dispensing section (68) with increasing approach to the outlet opening (64) of the air-enveloping part (14).

14. Dispensing device according to one of the preceding claims, characterized in that the width (B) of the outlet opening (64) of the air envelope part (14) in the jet plane (16) is 60 mm to 120 mm.

15. Dispensing device according to one of the preceding claims, characterized in that the flat jet nozzle (30) is designed to dispense a liquid jet expanding in a fan shape at a jet angle of 20° to 30°.

Images