Abstract:
A water jet ventilator or aerator is provided for a sanitary fitting such as a faucet. The water jet ventilator has a jacket defining a water inlet and a water outlet, jet splitting obstacles and structure for mixing the jets with air. The ventilator device splits the flowing water into jets, mixes the jets with air and combines the flow into a stream. In the vicinity of the water outlet, the ventilator components in contact with the water are subject to calcification. According to the invention these components are provided with soft and/or water repellent surfaces to reduce or eliminate calcification and to facilitate cleaning. The soft surfaces facilitate cleaning because adhering lime is easily be detached by slight manual deformation of the surfaces to which the lime has adhered.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of application Ser. No. 09/437,949, filed Nov. 10, 1999, now U.S. Pat. No. 6,588,682. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to a water jet ventilator or aerator for connection to a sanitary fitting, particularly a water outflow valve or mixer, having a water inlet, a water outlet and devices for splitting up and mixing the inflowing water with drawn in air, positioned between the water inlet and the water outlet. 
     Such water jet ventilators, also known as jet regulators, have a water inlet and a water outlet, as well as devices for splitting up the water flowing into the water jet ventilator positioned between the water inlet and the water outlet and which serve to mix the water with drawn in air. Water jet ventilators are nowadays widely used, because a ventilated or aerated water jet does not splash and allows a quiet inflow of water. In addition, e.g. for washing the hands, the water quantity can be reduced without this having a disadvantageous effect on the cleaning power. 
     The devices for splitting up and mixing the inflowing water with drawn in air normally operate in a number of stages. Firstly the inflowing water is split up by a device for producing single jets. For this purpose there are normally one or more superimposed perforated plates, the holes normally being staggered. Following this in the flow direction there is normally a free space or a chamber with the possibility of air access from below, so that here air can be drawn in according to the water jet pump principle. The individual jets are then split up in at least one splitting and mixing device following in the flow direction and are mixed with the drawn in air. 
     Considerable differences exist between conventional water jet ventilators particularly with respect to the devices for splitting up and mixing the individual jets with air. In many of these screen arrangements are provided for this purpose consisting of several fine, superimposed screens, through which the jet is split up and mixing with air is obtained. However, they tend to clog through calcification. To reduce the calcification problem devices have already been proposed which are free from such screens. 
     EP 151 998 discloses a screenless water jet ventilator which is provided below the individual jet production devices and the air chamber with several concentric, terraced devices for splitting up the individual jets and accompanied by a simultaneous mixing with air, to which are connected concentric guide channels, which serve to calm and stabilize the water/air mixture. The guide channels have common partitions formed by concentric sleeves, whose height increases from the inside to the outside and which are cross-sectionally constructed in the manner of step pyramids, i.e., they pass in terraced manner to either side. This geometrically relatively complex structure has only a limited calcification tendency and permits the formation of a uniformly ventilated full jet. 
     In a screenless jet regulator known from DE 196 42 055 the calcification problem is counteracted in that for splitting up the individual jets and the mixing thereof with air, in the flow direction is provided a multilayer arrangement of pins arranged transversely to the flow direction and which are parallel to one another. As a result intersections are avoided, which in conventional screen structures are favored points for the accumulation of water and subsequent lime formation or calcification. 
     SUMMARY OF THE INVENTION 
     The problem of the invention is to further improve known water jet ventilators with regards to their calcification behavior. 
     According to the invention this problem is solved in that in a known water jet ventilator at least one component of the water jet ventilator coming into contact with water in the vicinity of the water outlet is provided at least in said water outlet area with a soft and/or water-repelling surface. The term water-repelling surface is in particular intended to cover those surfaces which as a result of external pressure are easily and in particular reversibly deformable, i.e. preferably elastic, flexible surfaces. Water-repelling in the sense of the invention is a property of a surface if, as a result of its chemical and/or physical characteristics and/or its structure is only wetted with difficulty by water, i.e. has a high interfacial energy relative to water. 
     The invention is based on a solution fundamentally differing from the prior art, in that an attempt is not or not only made by means of a specific geometrical arrangement of components and/or their purpose-design shaping to increase the security against calcification, but instead to a particular extent surface characteristics of components are influenced, which are in particular located in the calcification-endangered area of the water outlet. If a water tap or the like is switched off, then normally residual water continues to adhere to components in the vicinity of the water outlet and slowly evaporates, so that normally a lime residue is left behind at the attachment point of the evaporated droplet. The resulting calcification more particularly occurs in the vicinity of the outlet end due to gravity and as a result said end can slowly clog or block. 
     According to the proposal of the invention at least the area of the outlet end is made lime-repelling in that at the endangered surfaces either water droplets do not adhere or only adhere to a limited extent or with a limited volume or their contact surface with the component is so small that only quasi-punctiform lime residues are left behind. As a function of the surface characteristics alternatively or additionally in the case of soft surfaces possibly deposited lime can be removed and detached by slight deformation or bending of the component surface. Thus, on the one hand calcification can be avoided or minimized from the outset and alternatively or additionally easier cleaning possibilities can be created for calcified elements in the vicinity of water outlets. 
     As the invention substantially relates to the surface characteristics of jet guidance elements and/or jet obstacles in the vicinity of the water outlet, the invention can be used with advantage in all water jet ventilators and optionally their geometry optimized with respect to calcification and/or other characteristics can be largely or completely retained. Preferably, the invention is implemented with screenless jet ventilators or regulators. 
     The invention can be implemented in different ways. Thus, it is e.g. possible for at least one of the particularly calcification-endangered components of said type to be made substantially completely from a soft and/or water-repelling material, particularly from a corresponding plastic. Components made from suitable solid material can generally be particularly inexpensively manufactured. The construction from solid material is particularly intended for those components which, as a result of their dimensioning and/or shaping have a certain shape stability and/or those which in the operation of the water jet ventilator have boundary surfaces substantially parallel to the flow direction, so that they are only moderately affected by the flowing water. Thus, the components, e.g. axial guidance elements, can be generally made from soft, particularly elastomeric plastic, such as silicone rubber or the like and in particular from thermoplastic elastomers. The thermoplastic elastomers e.g. include Santopren®, a polymer based on polypropylene and EPDM (ethylene/propylene/diene terpolymer). It is also possible to use primarily water-repelling materials, such as polytetrafluoroethylene (PTFE) or silicones, such as silicone resins. In the case of a correspondingly thin construction they can also have an adequate softness or flexibility. In the case of components, whose calcification-reducing characteristics are essentially based on the surface softness, it must in particular be ensured that at least the area of the soft surface is manually accessible, so that any deposited lime can be manually removed by deformation of the components or can be chipped off. Particularly suitable are soft materials with a hardness between approximately 20 and approximately 80 Shore A and for solid material components hardnesses in the upper range, e.g. between 50 and 80 Shore A, particularly approximately 80 Shore A are preferred, so as to give the components a certain dimensional stability in spite of the desired flexibility. 
     It is also possible for at least one component, at least in the vicinity of the water outlet, to have a coating or covering of a soft and/or water-repellent material. This coating can be applied to a support, whose mechanical characteristics essentially determine the volume properties of the component, such as stiffness or the like, whilst the coating creates the desired surface characteristics. Particular preference is given to water-repellent coatings with hydrophobic plastics, e.g. silicone or polytetrafluoroethylene, which can be applied to the support structure e.g. by spraying, dipping or other suitable processes. 
     Primarily water-repellent coverings can be very thin and generally only insignificantly change the geometry of the support structure. Preferred coating thicknesses can here be less than 0.1 mm, particularly between approximately 1 and 10 μm. In the case of a coating with a primarily soft material it is preferably ensured that the coating thickness is dimensioned in such a way that the coating is intrinsically movable, particularly compressible, in order to encourage the chipping off of lime residues by pressure on the coating. Coating thicknesses of more than 0.1 mm, particularly between 0.2 and 0.4 mm can be appropriate. As in the case of coatings the volume characteristic of the component, such as its stiffness, is essentially determined the support material, the material of the coating, whose hardness is appropriately between approximately 20 and approximately 80 Shore A, can be located in the lower part of this hardness range, e.g. between approximately 20 and approximately 50 Shore A. Even limited stripping forces are sufficient to bring about a deformation causing lime to be chipped off. 
     According to another embodiment, points, particularly edges of components located at the water outlet are provided with a thicker coating and/or are constructed in pointed or knife blade-like manner in the water outlet direction. On the one hand this improves the deformability and on the other brings about a good detachment of the water droplets. The coating thickness at these points can be up to 2 mm or more. 
     The advantages of the invention can also be utilized in that with the water jet ventilator is associated at least one component in the form of a flat or surface element through which there is a flow and positioned or positionable close to the water outlet and which has a soft and/or water-repellent surface. The flat element can be designed in such a way that it substantially covers the entire cross-section of the water outlet and forms a lower termination of the water jet ventilator, where preferably residual water collection takes place. Thus, further inwardly positioned components are better protected from the outset against lime accumulations, because residual water generally sticks to the furthest downwardly positioned parts. Simultaneously a protection of the inner components against mechanical damage is provided. The flat element can in particular be a grid or grating with randomly designed water outlets. It can in particular be a rectangular, diamond-shaped or honeycomb grating. Spiral or perforated disk-like flat elements are also possible. At least in the through-flow area, the flat element can be substantially completely made from soft and/or water-repellent material or can be coated with such a material. 
     Preferably the flat element is constructed as an insert detachably connectable to the water jet ventilator. A flat element can also be connected in fixed form to the water jet ventilator, e.g. molded into the same. 
     In preferred embodiments all components of the jet ventilator or regulator which come into contact with water, have water-repelling surface characteristics, at least those which also come into contact with air and where an evaporation of water can take place. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and further features of the invention can be gathered from the following description of preferred embodiments in conjunction with the subclaims and drawings. The individual features can be implemented singly or in the form of combinations. In the drawings show: 
     FIG. 1 Two juxtaposed axial sections through two embodiments of inventive water jet ventilators, which are substantially identical with regards to the geometry of their components. 
     FIG. 2 A larger scale detail view of the encircled area I of the left-hand embodiment of FIG.  1 . 
     FIG. 3 A partly broken away side view of another embodiment of an inventive water jet ventilator with a circular grating inserted in the area of the water outlet. 
     FIG. 4 A larger scale detail view of the encircled area IV of FIG. 3 without a grating. 
     FIG. 5 A larger scale, detail perspective view of the grating structure of FIG.  3 . 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1 shows two juxtaposed, differing embodiments of a substantially cylindrical water jet ventilator or aerator  1 , both embodiments being identical with regards to the geometry of the components and are therefore jointly represented. In per se known manner the water jet ventilator is fixed by a sleeve  4  having an external thread  2  and a bearing shoulder  3  and accompanied by the interposing of a packing ring  5 , to the outlet of a water tap or faucet  6  or an intake for a bath tub or the like. The water jet ventilator I is an example of the jet regulators of the type shown in EP 151 998, whose geometrical features regarding arrangement and/or dimensioning of individual components can be implemented in substantially unchanged form in the inventive water jet ventilators. 
     Considered in the flow direction, the ventilator  1  essentially comprises four functional units. These are a device  7  for producing individual water jets, the device comprising two perforated plates  8  and  9  with staggered holes, an air space  10  located below it and which is supplied with suction air through lateral openings  11 , several concentric, terraced devices forming jet splitting obstacles  12  for splitting up the individual jets accompanied by a simultaneous mixing with air, as well as connected, concentric guide channels  13 . The guide channels have common partitions  14  and additional radial partitions  15 , which at least at the outlet side are so thin that the air/water flows on passing out of the ventilator  1  combine to form a single, joint ventilated water jet. 
     There are four cylindrical sleeves  14  and  17  concentric to one another and serving as boundary or partition walls, which in the area of the water outlet  16  terminate in a common exit plane for the ventilated jet and bound four passage channels  13 , the central channel being cylindrical and the channels arranged around it are constructed as ring or circular channels, which are interrupted by eight web-like, radial partitions  15 . The outermost sleeve forms the outer jacket  17  of the jet ventilator with a conventional external diameter, which is provided in the upper region with a step-like widening or extension used for bearing on the shoulder  3  of the fixing sleeve  4 . 
     As can be seen in FIG. 2, the lower edges  18  of the partitions directed in the water outlet direction can be tapered, particularly asymmetrical, which facilitates the dripping of water. This preferably applies not only to the material of the partitions  14 . As shown, a correspondingly tapered lower edge  19  can be constructed from the material of the coating  20 . 
     The sleeves become increasingly long from the inside to the outside and carry on their upper ends annular attachments  22  to  24 , which are cross sectionally constructed in the manner of step pyramids, i.e. are terraced to either side. The attachments  22  to  24 , which bring about a splitting up of the individual jets formed by the lower perforated plate, are axially inwardly staggered in funnel-shaped manner and can therefore be mutually arranged with short radial spacings, without impairing the flow cross section for the air/water mixture between the attachments. The resulting dense arrangement of the jet splitting obstacles  12  with respect to the cross-section of the jet ventilator encourages the formation of a well ventilated full jet over the entire cross-section of the ventilator. The air/water mixture as split into several cascades flows through the concentric guide channels  13  to the water outlet  16 . 
     Particularly as a result of the smooth-walled limitation or boundary of the guide and outflow channels  13  and the absence of jet splitting screens towards its interior, the jet ventilator only has a limited calcification tendency. To further improve the calcification behavior in the right-hand embodiment the partitions  14  and the splitting obstacles  12  connected in one piece thereto are made from a relatively soft plastic with a Shore A hardness of approximately 70 to 80, e.g. a corresponding silicone elastomer. Material with such a hardness gives the components an adequate stability in the vicinity of the cross-sectionally wider step parts, but in the vicinity of the outlet  16  permits a slight manual bending of the free ends of the guide sleeves  14 , which are readily accessible in this area, e.g. with a fingertip  25  and as can be gathered from the broken line representation. As a result a very easy and effective cleaning possibility is created, particularly in the especially calcification-sensitive area of the outlet  16 , where residual water can adhere in preferred manner, evaporates and is deposited in lime residue form. With the easy manual bending possibility with respect to the partition ends, any deposited lime chips off or is at least detached to such an extent that during the next flushing of the jet ventilator the released lime deposits are flushed out. 
     The left-hand embodiment does not solve the calcification problem primarily by a facilitated cleaning possibility, but in that calcification is avoided from the outset by a special design of the surface characteristics of the partitions in the vicinity of the outlet. Thus, in this embodiment the sleeves  14  are completely covered with an approximately 10 pm thick coating  20 , which in this case comprises polytetrafluoroethylene and can e.g. be applied by dip coating or spraying of the parts to be coated. As a result of the closed coating  20  the entire surface in contact with water of said sleeves  14 ,  17  is made water-repelling, in that the interfacial energy with respect to water is so reduced that surface wetting is substantially prevented. After turning off the water tap, any residual water drips away and any remaining small drops preferably collect at the lowest points of the sleeves, i.e. generally on the lower face. Following evaporation of the water only on the small-area contact points between water droplets and the coating are there any lime residues, which due to their position outside the water guidance channels do not impair the function of the water jet ventilator and can be easily wiped off by hand due to their external position. As the outlet-near surfaces of the water splitting and guiding device are more liable to calcification than the terraced portions due to the easier air access, it may be adequate to e.g. only coat the part of the cylindrical guides  14 , whilst leaving the area of the step portions  22  to  24  uncoated. Coating is possible both on relatively hard, conventional materials and inventive, soft components in much the same way as in the right-hand embodiment. Thus, the components can e.g. be made from a rubberlike material, which is provided with a thin, water-repelling coating. 
     Other possibilities for a practical, cost-effective implementation of the invention are explained relative to FIGS. 3 to  5 . The jet regulator  30  shown therein has a hinged, sleeve-like casing  31 , which is formed by two sleeve halves  33 ,  34  joined in articulated manner by means of film hinges  32 . Also in this embodiment in the concealed upper area a perforated plate produces individual jets, which in the vicinity of a splitting and ventilating device  35  are split up, mixed with drawn in air and subsequently delivered through a lower, circular water outlet  36 . The splitting device  35  essentially comprises several successive layers of pins  37  which are arranged in parallel transversely to the flow direction and which are formed by pairwise associated pin portions aligned with one another when the device is folded up. The pin portions are in each case connected in one piece with the associated sleeve halves and abut with one another in the folded up state by means of frontal, complementary holding contours. The shaping and dimensioning of the jet regulator  30  can be the same as for the jet regulator of DE 196 42 055. 
     Due to the absence of screens and also due to the absence of intersections between the pins, the jet forming device of this water jet ventilator has only a limited calcification tendency. The calcification tendency can be further reduced if at least the splitting pins  38  close to the water outlet and optionally also the layer of pins  39  upstream in the flow direction, are coated with a hydrophobic coating  40 , as is diagrammatically shown in the larger scale detail view of FIG.  4 . This coating  40 , which is only a few micrometers thick and which can e.g. be of silicone or polytetrafluoroethylene, can be applied following the injection molding of the sleeve parts  3 : 3 ,  34 , e.g. by the dip coating of the sleeve halves or by spraying. The water-repellent coating  40  only allows a limited accumulation of residual water in the area of the water outlet  36 , because the residual water contracts to form spherical water droplets and which easily drip off the cross-sectionally circular pins without sticking thereto. In particular, residual water drops are avoided, which in the case of untreated jet ventilators of this type can adhere in bridge-like manner between neighboring pins of a layer or neighboring layers. 
     By means of FIGS. 3 and 5 a further possibility is explained for using the inventive advantages inexpensively both in numerous conventional water Ventilators and also in future ventilators. In the case of the water jet ventilator  30  the pin layer  38  closest to the outlet is inwardly offset by about 1 to 1.5 mm compared with the plane of the water outlet  36 . Into the remaining free space is inserted a grid or grating  45  completely filling the cross-section of the water outlet. In the represented embodiment said grating is manufactured as a separate component and has been inserted prior to the folding together of the casing halves  33 ,  34 . When the casing is completely fitted the grating  45  is positively held in a suitable receptacle  46  and rests in wobble-free manner on the lower casing end. A closing grating or the like can also be firmly connected to a casing of the jet ventilator, e.g. by molding the grating structure following the production of the casing. 
     The flow-through flat or surface element formed by the rectangular grating  45  (FIG. 5) forms the component structure of the ventilator coming into contact with water and closest to the water outlet  36  and preferably serves as a residual water collection point. Through the grating  45  residual water is more particularly also removed from the pin layer  38  closest to the opening, because droplets collecting there can easily bridge a gap to the grating and can “climb down” to the grating. In order to utilize the advantages according to the invention, at least in the through-flow inner area, such a flat element can be made from a soft and/or water-repelling material or can be coated with such. The preferably wide-meshed grating structure can be adapted to the flow geometry of the splitting and mixing device and can e.g. have a rectangular (FIG.  5 ), diamond-shaped, honeycomb or radial arrangement of grating stays  47 . Flat elements in the form of spiral inserts or perforated disks are also possible. 
     If the self-supporting flat element, as in the preferred embodiment of FIG. 3, is made from an adequately soft material with a Shore A hardness of e.g. between 50 and 80, lime residues which preferably form at the exposed underside of the grating, can be detached or chipped off by pressing in the grating (arrow) and the resulting bending thereof (broken lines). Particularly in the case of soft gratings, it is therefore suitable to provide a free space of approximately 0.5 to 1 mm between the last component structure of the splitting and guiding device facing the grating and formed by the pin layer  38  and it is preferably dimensioned in such a way that inner components can serve as a stop for avoiding an unnecessarily great, structure-hazarding bending. 
     In a not shown variant, the supporting grating structure is made from relatively hard, flexurally stiff plastics material and subsequently coated with an approximately 10 pm thick silicone resin layer. This gives the grating a water-repelling surface, from which residual water largely drips off and only small droplets form on the underside of the grating. The lower edges of the grating or the underside of the grating stays are advantageously tapered, as in the embodiment according to FIG.  2 . 
     The invention more particularly proposes in the case of water jet ventilators or jet regulators of any random construction to provide the normally plastic parts at the lower outlet end, where residual water collects in preferred manner due to gravity, either with a soft and/or water-repelling coating or to construct the actual components with a corresponding plastic. Preferred materials which, as a function of the material thickness, can be both adequately soft, but in particular also water-repelling, are inter alia the polytetrafluoroethylene known as Teflon, silicone resin or silicone rubber or other plastics having comparable characteristics, particularly elastomeric thermoplastics. Through the use of such materials for the manufacture and/or coating of outlet-near components in water jet ventilators an extremely cost-effective possibility is created for achieving a better calcification protection for such ventilators.