Device for enclosing a liquid jet with an air flow and liquid dispensing device with such a device

Abstract

The invention relates to a device (14; 92) for enclosing a liquid jet (42) that expands in a fan shape in a jet plane (44) with an airflow, wherein the device (14; 92) forms a housing (30; 104) that surrounds a through channel (36) and has at least one air intake opening (46, 48), wherein the through channel (36) has a first channel section (38) for receiving the liquid jet (42) and a second channel section (40) for discharging the liquid jet (42), wherein the first channel section (38) is in flow communication with the at least one air intake opening (46, 48) and the second channel section (40) expands in the jet plane (44).To further develop the device (14; 92) so that it can be attached to a dispensing element in a more user-friendly manner, the invention proposes that the housing (30; 104) has a retaining section (32; 106) which is configured for the detachable and rotationally fixed attachment of the device (14; 92) to a dispensing element (12; 94) which has a flat jet nozzle (22; 102). A liquid dispensing device (10; 90) with such a device (14; 92) is also proposed.

Description

The invention relates to a device for enveloping a liquid jet expanding in a jet plane in a fan-shaped manner with an air flow, wherein the device forms a housing which surrounds a through-channel and has at least one air intake opening, wherein the through-channel has a first channel section for receiving the liquid jet and a second channel section for discharging the liquid jet, and wherein the first channel section is in flow connection with the at least one air intake opening and the second channel section expands in the jet plane.The invention also relates to a liquid dispensing device for dispensing a liquid jet expanding in a fan-shaped manner in a jet plane, having a device of the above type and having a dispensing element which can be detachably connected to a liquid supply line and has a flat jet nozzle, wherein the device can be detachably connected to the dispensing element.Application elements with a flat jet nozzle for emitting a fan-shaped liquid jet are used, for example, as accessory parts for printing cleaning apparatuses in order to be able to sweep over an object to be cleaned with a fan-shaped liquid jet. The discharge elements 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, for example, from WO 2014 / 09033 A1.The fan-shaped liquid jet emerging from the flat jet nozzle is subject to an interaction with the ambient air on its path to the object to be cleaned. This has the result that the liquid jet is decelerated and loses compactness. In order to counteract this effect, JP 2004-223409 A proposes a liquid dispensing device in which, in addition to a dispensing element in the form of a feed tube which carries a flat jet nozzle at its free end, a device for enveloping the liquid jet which originates from the flat jet nozzle and widens in a fan-shaped manner is used. The feed pipe is welded to a retaining plate which is in turn screwed to the device. The device consists of two housing halves welded to one another, which are screwed to the retaining plate and surround a through-channel which reaches through the housing. The through channel has a first channel section for receiving the liquid jet emanating from the flat jet nozzle and a second channel section for discharging the liquid jet, wherein the first channel section is in flow connection with two air intake openings of the housing and the second channel section continuously widens as the distance from the first channel section increases. This makes it possible to mix air into the liquid jet, wherein the air forms an air jacket which surrounds the liquid jet and can be discharged together with the liquid jet from the liquid discharge device. The air jacket reduces the interaction of the liquid jet with the ambient air, wherein in particular the deceleration of the liquid jet is reduced and its compactness is less impaired. The first channel section of the through channel receives the liquid jet emanating from the flat jet nozzle, which exits from the flat jet nozzle at a considerable speed, so that air is drawn in via the air intake openings, which subsequently surrounds the liquid jet in the form of a jacket. By means of the device, the liquid jet emanating from the flat jet nozzle of the application element can thus be sheathed in a jacket-like manner by an air flow in order to reduce the deceleration of the liquid jet on account of its interaction with the ambient air. However, the handling of the device when fastening to the application element is not very easy to use.It is therefore the object of the present invention to further develop a device of the generic type in such a way that it can be fastened to a discharge element in a more operationally friendly manner.This object is achieved according to the invention in a device of the type mentioned at the beginning in that the housing has a holding section which is configured for the detachable and rotationally fixed fastening of the device to a discharge element which has a flat jet nozzle.By means of the holding section, the device according to the invention can be fastened in a simple manner to a delivery element which has a flat jet nozzle. If necessary, the device can also be easily detached from the application member. The discharge element, for example a jet pipe with an integrated flat jet nozzle, can be connected in the usual manner via a liquid supply line to a pressure cleaning device, so that pressurized liquid can be supplied to the discharge element, which liquid can be supplied to the device according to the invention via the flat jet nozzle in the form of a fan-shaped liquid jet, wherein the liquid jet can be picked up by the first channel section of the through channel and subsequently discharged via the second channel section of the through channel. The holding section enables a simple, detachable and rotationally fixed attachment of the device to the application member, wherein the rotationally fixed attachment ensures that the device maintains its rotational position relative to the application member, so that the liquid jet emanating from the flat jet nozzle can flow unimpeded through the passage channel of the housing, in particular the second channel section widening in the shape of a fan.By means of the holding section, the device according to the invention can be fastened to the application member without an additional connecting part being required, for example a holding plate which has to be welded to the application member and screwed to the device. The handling of the device according to the invention when fastening to the application member is thus very simple and easy to use.It is advantageous if the holding section is configured for the tool-free, detachable and rotationally fixed fastening of the device to a discharge element. As a result, the handling of the device when fastening to the application member is particularly easy to use.The holding section can, for example, form an elastically expandable holding clip which can be clipped onto an end section of the application element. Clipping-on can take place in the axial direction with respect to a longitudinal axis of the application element or else obliquely or perpendicularly to the longitudinal axis. The retaining clip can be C- or U-shaped, for example.It is advantageous if the holding section has a holding ring which is non-circular in cross section, in particular roll-shaped. The retaining ring can be placed on an end section of the application element, for example, in the axial direction with respect to a longitudinal axis of the application element. In particular in such an embodiment, the device according to the invention can form a placement part which can be placed on the application member and can also be placed again. The shape of the cross section of the retaining ring deviating from the circular shape enables a rotationally fixed connection of the retaining ring to the application member in a structurally simple manner. In particular, a roll-shaped cross section of the retaining ring has proven to be advantageous.The holding section preferably has at least one latching element. This makes it possible to latch the holding section to the application member, wherein the latching element of the holding section can interact with a latching element of complementary configuration of the application member in order to form a latching connection.It is particularly advantageous if the holding section has at least one coding element for positioning the device in a predetermined rotational position relative to the application member. By means of the at least one coding element, the fastening of the device to a discharge element can be effected in a rotational position in which the second channel section of the device is aligned in the jet plane of the liquid jet emanating from the flat jet nozzle of the discharge element. The at least one coding element forms a positioning aid which facilitates a user the fastening of the device to a discharge element in a predetermined rotational position.At least one coding element can be designed, for example, in the form of a coding slot which, when the device is fastened to the application element, accommodates a coding rib of complementary design of the application element.Alternatively or additionally, it can be provided that at least one coding element forms a contact surface which can be applied flat to a contact region of complementary configuration of the application element.As mentioned at the beginning, the housing of the device according to the invention has a through-channel through which the liquid jet can flow, with a first channel section for receiving the liquid jet and a second channel section for discharging the liquid jet, wherein the first channel section is in flow connection with at least one air intake opening and the second channel section widens as the distance from the first channel section increases in the jet plane. In a particularly preferred embodiment of the invention, the second channel section has a longitudinal region extending at least over part of its total length, in which the second channel section narrows with increasing distance from the first channel section perpendicular to the beam plane.In such a configuration of the device according to the invention, the second channel section of the housing widens as the distance from the first channel section increases in the beam plane and has a longitudinal region extending at least over part of its total length, in which region it narrows as the distance from the first channel section increases perpendicularly to the beam plane. The longitudinal region, which extends at least over a part of the total length of the second channel section and in which the second channel section narrows perpendicularly to the beam plane, counteracts an increase in the cross-sectional area of the second channel section, which is caused by the widening of the second channel section in the beam plane. This in turn counteracts a reduction in the flow speed of the air jacket which surrounds the liquid jet within the second channel section. The flow velocity of the air jacket depends on the size of the cross-sectional area of the second channel section. The more the cross-sectional area increases with increasing distance from the first channel section, the more the flow velocity of the air jacket decreases. By narrowing the second channel section perpendicular to the beam plane in the longitudinal region extending at least over a part of the total length of the second channel section, an increase in the cross-sectional area caused by the widening of the second channel section in the beam plane can be compensated at least partially. This in turn has the result that the flow velocity of the air jacket surrounding the liquid jet in the circumferential direction is less impaired within the second channel section. The lesser impairment of the flow speed of the air jacket in turn has the consequence that the liquid jet within the second channel section is decelerated less and the compactness of the liquid jet is impaired less. The device according to the invention is distinguished in such a configuration not only by easy handling during the fastening to a discharge element, but is also distinguished in that improved cleaning performance can be achieved when the device is used for cleaning an object. The liquid jet can also be further fanned out in such a configuration of the device, so that a greater cleaning width can be achieved with the same cleaning performance.The longitudinal region of the second channel section, in which the latter narrows with increasing distance from the first channel section perpendicular to the jet plane of the liquid jet, preferably extends over at least 50% of the total length of the second channel section, in particular over at least 75%, for example at least 80%.In particular, it can be provided that the longitudinal region of the second channel section, in which the latter narrows with increasing distance from the first channel section perpendicular to the beam plane, extends over the entire length of the second channel section. In such a configuration of the device according to the invention, the aforementioned longitudinal region extends as far as the free end of the second channel section.Alternatively, it can be provided that the aforementioned longitudinal region of the second channel section is adjoined by an end region of the second channel section widening with increasing distance from the first channel section perpendicular to the beam plane or remaining the same with respect to its extension perpendicular to the beam plane.The device according to the invention for enveloping a fan-shaped widening liquid jet with an air flow is suitable in combination with an application element with an integrated flat jet nozzle, in particular for use in pressure cleaning devices which provide a cleaning liquid, in particular water, with a pressure of 10 bar to 3,000 bar, in particular 10 bar to 300 bar.In order to be able to produce the housing cost-effectively, it is advantageous if the housing is designed as a one-piece plastic molded part.The housing preferably consists of a partially crystalline plastic material, in particular of a polypropylene, polyethylene, polyoxymethylene or polyamide material.It is advantageous if the housing, which is configured as a one-piece plastic molded part, has a housing base, which forms the first channel section of the through channel and to which two housing sections, which form the second channel section, connect, wherein a flexurally rigid deformation zone of the housing base is directly upstream of at least one of the housing sections. Such a configuration makes it possible to produce the housing cost-effectively in an injection molding process, wherein the housing initially has a demolding configuration in which the two housing sections are spread apart. After demolding has been completed, the housing can be transferred by bending the at least one deformation zone into a use configuration in which the two housing sections bear against one another and define the second channel section between them.As already mentioned, the second channel section widens in the beam plane with increasing distance from the first channel section, and preferably the second channel section narrows perpendicular to the beam plane at least over part of its total length with increasing distance from the first channel section. In order to be able to achieve such a geometry in an injection molding process in a simple manner, the housing can be produced in an injection molding process in a demolding configuration in which the two housing sections are spread apart, so that the housing can be easily demolded. After demolding has taken place, the at least one flexurally soft deformation zone can be bent to such an extent that the two housing sections bear against one another and define between them the second channel section of the through-channel. Difficulties in demolding the housing can thereby be avoided in a simple manner. In the position of use of the housing, the geometry of the second channel section ensures that the flow velocity of the air jacket which surrounds the liquid jet is impaired to a slight extent and consequently the liquid jet is at most slightly decelerated and loses compactness.In a preferred embodiment of the device according to the invention, the housing base has, in the region of the first duct section of the through duct, two air intake openings lying opposite one another, which are directly upstream of the second duct section and which are connected to one another via the at least one deformation zone. In such a configuration, the flow resistance of the air sucked into the first channel section under the action of the liquid jet can be kept particularly low, since the air intake openings open directly into the first channel section, and, when the housing changes from the demolding configuration into the use configuration, the at least one deformation zone, which is arranged between the mutually opposite air intake openings of the first channel section, is deformed.In particular, it can be provided that the two air intake openings are connected to one another via two deformation zones of the housing base which are situated opposite one another and are arranged outside the jet plane.It is advantageous if the two deformation zones are arranged mirror-symmetrically to the beam plane.The opening axes of the air intake openings are expediently aligned coaxially with respect to one another and are arranged in the jet plane of the liquid jet.It is advantageous if the material thickness of the housing is less in the region of the at least one deformation zone than outside the at least one deformation zone. The smaller material thickness in the region of the at least one deformation zone facilitates the bending of the at least one deformation zone during the transition from the demolding configuration to the use configuration.In a particularly preferred embodiment of the device, the two housing sections, which define between them the second channel section of the through-channel, can be fixed to one another. The mutual fixing of the two housing sections gives the housing sections a high bending stiffness in the use configuration of the housing, so that the housing sections in the use configuration also withstand high external bending loads without there being the risk that they shift relative to one another in the event of a mechanical load.It is advantageous if the two housing sections can be locked to one another. For this purpose, the two housing sections can have mutually interacting latching elements, for example latching hooks, which engage behind one another in a latching position.It is advantageous if the two housing sections form edge regions which delimit the extent of the second channel section in the beam plane and have projections and depressions which engage one another in pairs perpendicularly to the beam plane. The edge regions of the two housing sections form channel walls of the second channel section of the through channel, which delimit the extent of the second channel section in the beam plane. The edge regions have projections and depressions which engage in pairs in the position of use of the housing. The edge sections thus form a type of toothing which gives the two housing sections a very high bending stiffness in the use configuration of the housing.As already mentioned, the invention also relates to a liquid dispensing device for dispensing a liquid jet expanding in a fan-shaped manner in a jet plane, wherein the liquid dispensing device has a device of the type explained above, and a dispensing element which can be detachably connected to a liquid supply line and has a flat jet nozzle, wherein the device can be detachably and non-rotatably connected to the dispensing element.As already mentioned, the device according to the invention can form a placement part for the application element.It can be provided that the discharge element is designed as a jet pipe which has a single nozzle in the form of a flat jet nozzle. Such jet pipes are also referred to as single jet pipes.Alternatively, it can be provided that the discharge element is designed as a multiple jet pipe, which has a plurality of nozzles, via which a liquid jet can be selectively discharged, wherein one of the nozzles is designed as a flat jet nozzle. Such multiple jet pipes are known, for example, from WO 2012 / 095238 A1.The following description of advantageous embodiments of the invention serves to explain it in more detail in conjunction with the drawing. The following are shown: FIG. 1 : a side view of a first embodiment of a liquid dispensing device with a dispensing element in the form of a multiple jet tube and with a first embodiment of a device for enveloping a liquid jet with an air flow; FIG. 2 : a side view of the device from FIG. 1 ; FIG. 3 : a plan view of the device from FIG. 1 ; FIG. 4 is a front view of the device from FIG. 1 ; FIG. 5 is a sectional view of the apparatus taken along line 5- 5 in FIG. 2 ; FIG. 6 is a sectional view of the apparatus taken along line 6- 6 in FIG. 2 ; FIG. 7 is a sectional view of the apparatus taken along the line 7- 7 in FIG. 3 ; FIG. 8 is a front view of the apparatus of FIG. 4 with a housing of the apparatus in a demolding configuration; FIG. 9 is a sectional view of the apparatus taken along line 9--9 of FIG. 8; FIG. 10 is a sectional view of the liquid dispenser taken along line 10--10 of FIG. 1; FIG. 11 : a perspective illustration of an end region of the application element from FIG. 1 ; FIG. 12 : shows a perspective illustration of a second embodiment of a liquid dispensing device having a dispensing element in the form of a single jet tube and having a second embodiment of a device for enveloping a liquid jet with an air flow; FIG. 13 is a plan view of the liquid dispensing device of FIG. 12 ; FIG. 14 is a front view of the liquid dispensing device of FIG. 12 ; FIG. 15 is a sectional view of the liquid dispenser taken along line 15--15 in FIG. 14; FIG. 16 is a sectional view of the liquid dispenser taken along line 16--16 of FIG. 13; FIG. 17 shows an enlarged illustration of detail X from FIG. 16.In FIGS. 1 to 11, a first advantageous embodiment of a liquid dispensing device according to the invention is schematically illustrated and denoted overall by the reference numeral 10.The liquid dispensing device 10 has a dispensing element in the form of a multiple jet pipe 12 and a first advantageous embodiment of a device 14 according to the invention for enveloping a liquid jet provided by the multiple jet pipe 12 and widening in a fan-shaped manner in a jet plane with a jacket-shaped air flow.The multiple jet pipe 12 has at a first end region 16 a bayonet connecting member 18 with the aid of which the multiple jet pipe 12 can be connected to a liquid supply line which is known per se and therefore not shown in the drawing in order to achieve a better overview, via which liquid pressurized by a pressure cleaning device which is known per se and therefore likewise not shown in the drawing can be supplied to the multiple jet pipe. As is evident in particular from FIG. 10, the multiple jet pipe 12 has, on a second end region 20 facing away from the first end region 16, three differently configured nozzles in the form of a flat jet nozzle 22, a rotor nozzle 24 and a point jet nozzle 26, via which the supplied liquid can be selectively discharged. For this purpose, the jet pipe 12 has a nozzle changeover arrangement which is known per se and is therefore not shown in the drawing in order to achieve a better overview and is coupled to an outer sleeve 28 which can be gripped by the user. The outer sleeve 28 is rotatable about a longitudinal axis of the jet pipe, and depending on the rotational position of the outer sleeve 28, the nozzle switching arrangement opens up a flow path from the first end region 16 to one of the nozzles 24, 26 or 28, so that depending on the rotational position of the outer sleeve 28, a liquid jet can be selectively discharged via one of the nozzles 24, 26, 28. Such multiple jet pipes are known to the person skilled in the art, for example from WO 2012 / 095238 A1.By means of the flat jet nozzle 22, a liquid jet widening in fan-shaped fashion in the jet direction can be discharged. Such flat jet nozzles are known to the person skilled in the art, for example from WO 2014 / 09033 A1. A point jet can be emitted by means of the point jet nozzle 26, that is to say a liquid jet which expands only insignificantly in the jet direction. By means of the rotor nozzle 24, a point jet rotating on a conical jacket can be generated. Such point jet and rotor nozzles are also known to the person skilled in the art.The device 14 is designed in the manner of an attachment which is placed on the second end region 20 of the jet pipe.As can be seen from Figures 2 to 10, the device 14 comprises a housing 30 which comprises a housing base 31. Upstream of the housing base 31 in the direction of the multiple jet tube 12 is a holding section 32 of the housing 30, which is designed in the form of a holding ring 33. The retaining ring 33 is substantially Whetel-shaped in cross section. This is clear in particular from FIG. 10. The cross-sectional shape of the retaining ring 33 corresponds largely to the cross-sectional shape of the second end region 20 of the multiple jet pipe 12.On its inner side facing the multiple jet pipe 12, the retaining ring 33 has three latching projections 34 which are arranged so as to be uniformly distributed in the circumferential direction and each dip into a latching depression 35 arranged on the outer side of the multiple jet pipe 12. The device 14 is consequently latchable with the multiple jet pipe 12 and can be detached from the multiple jet pipe 12 if required.In the region between two latching depressions 35, the multiple jet pipe 12 has on its outer side an abutment region in the form of a shoulder 36 to which an abutment surface 37 arranged on the inner side of the retaining ring 33 is assigned, which abutment surface comes to bear against the shoulder 36 when the retaining ring 33 is placed on the end region 20 of the multiple jet pipe 12. This is clear in particular from FIGS. 10 and 11. The shoulder 36 and the contact surface 37 form coding elements which are associated with one another and ensure that the device 14 can only be placed on the end region 20 of the multiple jet tube 12 in a predefined rotational position relative to the multiple jet tube 12.Flush with the flat jet nozzle 22, a through channel 36 of the device 14 is connected, which is surrounded by the housing 30. The through-channel 36 has a first channel section 38 and a second channel section 40 directly adjoining the latter. The first channel section 38 receives the liquid jet emanating from the flat jet nozzle 22. The flat jet nozzle 22 is shown in dashed lines in FIGS. 6 and 7 for easier orientation, and the liquid jet emanating from the flat jet nozzle 22 is shown in dashed lines in FIGS. 6 and 7 for easier orientation and is denoted by the reference sign 42. The liquid jet 42 widens in the jet direction in a fan-shaped manner and defines a jet plane 44.The liquid jet is emitted via the second channel section 40, so that it can be directed, for example, onto an object to be cleaned. In order for the liquid jet 42 to be able to flow through the second channel section 40 in a contactless manner, the second channel section 40 widens continuously in the jet plane 44 with increasing distance from the first channel section 38.Perpendicular to the beam plane 44, the second channel section 40 narrows continuously over its entire length with increasing distance from the first channel section 38. The continuous widening in the jet plane 44 and the continuous narrowing perpendicular to the jet plane 44 ensure that although the shape of the cross-sectional area of the second channel section 40 changes continuously with increasing distance from the first channel section 38, the size of the cross-sectional area of the second channel section 40 remains virtually constant over its entire length.The housing base 31 surrounds the first duct section 38, which has two mutually opposite, identically configured air intake openings 46, 48. The air intake openings 46, 48 are directly upstream of the second duct section 40. As is evident in particular from FIG. 6, the opening axes 50, 52 of the air intake openings 46, 48, that is to say the central axes of the air intake openings 46, 48, are aligned coaxially with respect to one another and are arranged in the jet plane 44 of the liquid jet 42.A negative pressure forms within the first channel section 38 under the action of the liquid jet 42 emerging from the flat jet nozzle 22, so that air is sucked into the first channel section 38 via the air suction openings 46, 48, which air is mixed with the liquid jet 42. An air jacket is formed here, which surrounds the liquid jet 42 in the circumferential direction. The flow velocity of the air jacket remains virtually constant within the second channel section 40, since the size of the cross-sectional area of the second channel section 40 remains virtually constant over its entire length. As already mentioned, although the second channel section 40 widens in the beam plane 44, the associated increase in the cross-sectional area is compensated for by the narrowing of the second channel section 40 perpendicular to the beam plane. The practically constant flow velocity of the air jacket has the consequence that flow losses of the liquid jet 42 within the second channel section 40 can be kept low, in particular the deceleration of the liquid jet 42 within the second channel section 40 can be kept low and the compactness of the liquid jet 42 is only slightly impaired. This improves the cleaning effect that can be achieved by means of the liquid jet 42.Adjoining the side of the housing base 31 facing away from the holding section 32 are a first housing section 54 and a second housing section 56, which define between them the second channel section 40 of the through channel 36. Directly upstream of the first housing section 54, the housing base 31 forms a first web-like, flexible deformation zone 58 between the two air intake openings 46, 48, and the housing base 31 directly upstream of the second housing section 56 forms a second web-like, flexible deformation zone 60 between the two air intake openings 46, 48. The two deformation zones 58, 60 are of identical configuration and are arranged mirror-symmetrically with respect to the beam plane. This is clear in particular from FIG. 2. The housing 30 has a smaller material thickness in the region of the two deformation zones 58, 60 than outside the deformation zones 58, 60. This makes it possible to change the orientation of the two housing sections 54, 56 during the production of the housing 30.The housing 30 is configured as a one-piece molded plastic part and consists of a partially crystalline material, for example of a polypropylene, polyethylene, polyoxymethylene or polyamide material.An injection molding method is used to produce the housing 30, wherein the housing 30 initially assumes a demolding configuration in which the two housing sections 54, 56 are spread apart. The demolding configuration of the housing 30 is schematically illustrated in FIGS. 8 and 9. This configuration makes it possible to easily demold the housing 30 despite the geometry of the second channel section 40 which widens continuously in the beam plane and narrows continuously perpendicular to the beam plane 44. During the transition from the demolding configuration to the use configuration, the flexurally soft deformation zones 58, 60 bend in the manner of film hinges.In the use configuration of the housing 30, the two housing sections 54, 56 can be fixed to one another. This gives the housing sections 54, 56 a high bending stiffness in the use position.As is evident in particular from FIG. 5, the two housing sections 54, 56 each have two edge regions 62, 64 and 66, 68, respectively, which limit the extent of the second channel section 40 in the beam plane. The edge regions 62, 64, 66 and 68 have latching hooks 70, 72 which cooperate in pairs and engage behind one another in the use position of the housing 20 and form a latching connection, so that the housing sections 54, 56 can be latched to one another in the use position of the housing 30. The latching hooks 70, 72 extend in the longitudinal direction of the second channel section 40 in a central section of the edge regions 62, 64, 66, 68 and in an end section of the edge regions 62, 64, 66, 68. In the sections lying therebetween, the edge regions 62, 64 of the first housing section 54 have depressions 74, 76, into each of which a complementarily configured protrusion 78, 80 of the edge regions 66, 68 of the second housing section 56 dips in a positive-locking manner. This is clear in particular from FIG. 2. The depressions 74, 76 and the projections 78, 80 thus form a toothing of the two housing sections 54, 56 in the region of the beam plane 44, by means of which toothing the bending rigidity of the housing 30 is additionally increased. In particular, the depressions 74, 76 and the projections 78, 80 ensure that the two housing sections 54, 56 do not shift relative to one another under the action of an external bending moment.By means of the device 14, a liquid jet 42 which issues from the flat jet nozzle 22 and which widens in a fan-shaped manner can be surrounded by a jacket-shaped air flow, by means of which the impairment of the liquid jet 42 by the ambient air can be kept very low. The housing 30 of the device 14 can be produced here cost-effectively in a plastic injection molding process, wherein it initially assumes a demolding configuration which makes it possible to easily demold the housing 30 despite the geometry of the second channel section 40 widening in the jet plane and tapering perpendicularly to the jet plane. For this purpose, the two housing sections 54, 56 defining the second channel section 40 are spread apart in the demolding configuration, whereas in the use configuration of the housing 30, they abut against one another with lateral edge regions, wherein the edge regions can be latched to one another and, as a result of the provision of the depressions 74, 76 and the projections 78, 80, form a toothing which gives the housing sections 54, 56 a high bending stiffness in the use position despite the provision of the two flexurally flexible deformation zones 58, 60 which deform during the transition of the housing from the demolding position into the use position.FIGS. 12 to 17 schematically show a second advantageous embodiment of a liquid dispensing device according to the invention, which is denoted overall by the reference sign 90. The liquid dispensing device 90 has a dispensing element in the form of a single jet pipe 94 and a second advantageous embodiment of a device according to the invention for enveloping a liquid jet provided by the single jet pipe 94 and widening in a fan-shaped manner in a jet plane with a jacket-shaped air flow, wherein the device is denoted by the reference symbol 92.In a manner corresponding to the multiple jet pipe 12 of the liquid dispensing device 10 explained above, the single jet pipe 94 also has a first end region 96, on which a bayonet connecting member 98 is arranged for releasable connection to a liquid supply line, via which liquid pressurized by a pressure cleaning device can be supplied to the liquid dispensing device 90.At a second end region 100 facing away from the first end region 96, the single jet pipe 94 has a flat jet nozzle 102. The flat jet nozzle 102 can be configured identically to the flat jet nozzle 22 mentioned above with reference to the first liquid dispensing device 10.The device 92 forms an attachment which can be placed on the second end region 100 of the single-jet pipe 94. The device 92 is largely identical to the device 14 explained above. For identical components of the device 92, the same reference numerals are therefore used in FIGS. 12 to 17 as in FIGS. 1 to 11, and with regard to these components reference is made to the explanations given above in order to avoid repetitions.The device 92 differs from the device 12 by a housing 104 which forms a holding section 106 in the form of a circular cylindrical holding sleeve 108, which can be placed on the cylindrically configured second end region 100 of the single jet pipe 94 and can also be removed again if necessary. The end region 100 has on its outer side a plurality of outwardly directed ribs 110 arranged axially offset from one another. The holding sleeve 108 has on its inner side radially inwardly pointing latching projections 112 which, when the device 92 is placed on the end region 100 of the single jet tube 94, dip into an intermediate space 114 between two adjacent ribs 110. In this way, the device 92 can be locked to the single jet pipe 94. If necessary, the device 92 can also be removed again from the single jet pipe by releasing the locking connection.In order to ensure a rotationally fixed connection and to align the second channel section 40 of the device 92 in the jet plane of the liquid jet emanating from the flat jet nozzle 102, the holding sleeve 108 has an encoding element in the form of an encoding slot 116, which interacts with a complementarily configured encoding element in the form of an encoding rib 118 which is arranged on the outer side of the single jet pipe 94. Upon placement of the device 92 onto the second end portion 100 of the single beam tube 94, the coding slot 110 can receive the coding rib 112. The device 92 is thereby secured against rotation relative to the jet pipe 94 and at the same time it is ensured that the second channel section 40 of the housing 104 is aligned coplanar with the jet plane of the liquid jet emanating from the flat jet nozzle 102.The housing 104 is designed in a corresponding manner to the housing 30 explained above as a one-piece plastic molded part and can be produced by injection molding, wherein the housing 104 initially assumes a demolding configuration and can subsequently be transferred into a use configuration, as has already been explained above.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedWO 2014 / 09033 A1 [0003, 0042]JP 2004-223409 A

[0004] WO 2012 / 095238 A1 [0037, 0041]

Claims

Device for enveloping a liquid jet (42), which widens in a fan-shaped manner in a jet plane (44), with an air flow, wherein the device (14; 92) forms a housing (30; 104) which surrounds a passage channel (36) and has at least one air intake opening (46, 48), wherein the passage channel (36) has a first channel section (38) for receiving the liquid jet (42) and a second channel section (40) for discharging the liquid jet (42), and wherein the first channel section (38) is in flow connection with the at least one air intake opening (46, 48) and the second channel section (40) widens in the jet plane (44), characterized in that the housing (30; 104) has a holding section (32; 106) which is configured for the detachable and rotationally fixed fastening of the device (14; 92) to a discharge element (12; 94) having a flat jet nozzle (22; 102).Device according to claim 1, characterised in that the holding section (32; 106) is configured for the tool-free, detachable and rotationally fixed fastening of the device (14; 92) to a discharge element (12; 92).Device according to claim 1 or 2, characterised in that the holding section (32) has a holding ring (34) which is non-circular in cross-section.Device according to claim 1, 2 or 3, characterised in that the holding section (32; 106) has at least one latching element (34; 112).Device according to one of the preceding claims, characterized in that the holding section (32; 106) has at least one coding element (37; 110) for positioning the device (14; 92) in a predetermined rotational position relative to the application member.Device according to claim 5, characterised in that at least one coding element is designed in the form of a coding slot (116).Device according to claim 5 or 6, characterised in that at least one coding element forms a contact surface (37).Device according to one of the preceding claims, characterized in that the second channel section (40) has a longitudinal region which extends at least over part of its total length and in which the second channel section (40) narrows with increasing distance from the first channel section (38) perpendicularly to the beam plane (44).Device according to one of the preceding claims, characterized in that the housing (30; 104) is designed as a one-piece moulded plastics part.Device according to claim 9, characterised in that the housing (30) consists of a partially crystalline plastic material.Device according to claim 9 or 10, characterised in that the housing (30; 104) has a housing base (31) which forms the first channel section (38) and to which two housing sections (54, 56) which form the second channel section (40) are connected, wherein at least one of the two housing sections (54, 56) is directly upstream of a flexurally soft deformation zone (58, 60) of the housing base (31).Device according to claim 11, characterised in that the housing base (31) has, in the region of the first duct section (38), two mutually opposite air intake openings (46, 48), which are directly upstream of the second duct section (40) and which are connected to one another via the at least one deformation zone (58, 60).Device according to claim 12, characterised in that the two air intake openings (46, 48) are connected to one another via two deformation zones (58, 60) which are situated opposite one another and are arranged outside the jet plane (44).Device according to claim 13, characterised in that the two deformation zones (58, 60) are arranged mirror-symmetrically to the beam plane (44).Device according to claim 12, 13 or 14, characterised in that the opening axes (50, 52) of the two air intake openings (46, 48) are aligned coaxially with one another and are arranged in the jet plane (44) of the liquid jet (42).Device according to one of Claims 11 to 15, characterized in that the material thickness of the housing (30) is less in the region of the at least one deformation zone (58, 60) than outside the at least one deformation zone (58, 60).Device according to one of Claims 11 to 16, characterized in that the two housing sections (54, 56) can be fixed to one another.Device according to claim 17, characterised in that the two housing sections (54, 56) can be locked to one another.Device according to claim 17 or 18, characterised in that the two housing sections (54, 56) have edge regions (62, 64, 66, 68) which limit the extent of the second channel section (40) in the jet plane and have projections and recesses which engage in one another in pairs perpendicularly to the jet plane (44).Liquid dispensing device for dispensing a liquid jet (42) widening in a fan shape in a jet plane, having a device (14; 92) according to one of the preceding claims and having a dispensing member (12; 94) which can be detachably connected to a liquid supply line and has a flat jet nozzle (22; 102), wherein the device (14; 92) can be detachably and non-rotatably connected to the dispensing member (12; 94).

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