Abstract:
A jet regulator ( 100 ) including a jet regulator housing ( 2 ) is disclosed, in the housing interior of which a perforated plate ( 5 ) is provided with a plurality of flow-through holes ( 6 ) for dividing the through-flowing water. The jet regulator described is characterised in that at least one flow-through hole ( 6 ) extends conically towards its outflow side in at least one outflow-side hole section. It is also possible for flow obstacles to be provided on the outflow side of the perforated plate ( 5 ) in the jet regulator housing ( 2 ) and/or on the outflow front face of the jet regulator housing, which are arranged or concentrated there in a central or middle region and which deflect the through-flowing water into an outer annular zone. This jet regulator ( 100 ) enables an aerated and thereby sparkling-soft water jet to be generated even with low flow-through performance and low water pressure.

Description:
BACKGROUND 
       [0001]    The invention relates to a jet regulator having a jet regulator housing, in the housing interior of which there is provided a perforated plate which has a multiplicity of throughflow holes for dividing the through-flowing water. 
         [0002]    Jet regulators of the type mentioned in the introduction are already known in a wide variety of embodiments. Jet regulators of said type are mounted on the water outlet of a sanitary outlet fitting in order to generate a homogenous and laterally non-sputtering water jet. Jet regulators also exist which aerate the out-flowing water jet and, for this purpose, are designed to mix the through-flowing water with the ambient air. 
         [0003]    For example, from DE 30 00 799 A1, an aerated jet regulator is already known which, in its jet regulator housing, has a perforated plate with a multiplicity of throughflow holes which are arranged in concentric hole circles on the perforated plate and which are intended to split up the water—flowing through the jet regulator housing into a corresponding number of individual jets. Since the throughflow holes constrict the clear throughflow cross section in the region of the perforated plate, the through-flowing water increases in speed in the throughflow holes, which, in accordance with the Bernoulli equation, results in a negative pressure on the outflow side of the perforated plate. Due to the negative pressure generated on the outflow side of the perforated plate, ambient air is drawn in, which ambient air can enter into the housing interior of the jet regulator housing through aeration openings provided in the housing wall and can mix there with the through-flowing water. In order that the through-flowing water is divided into individual jets by means of the perforated plate in a quiet manner, it is provided in the case of the jet regulator already known from DE 30 00 799 A1 inter alia that the throughflow holes have a hole section which is polygonal in cross section, downstream of which hole section there is provided a hole section which widens progressively in terms of cross section and which is cylindrical at the outflow side (see FIG. 4 in DE 30 00 799 A1). By means of throughflow holes of said type which have different sections, an individual jet which is of circular cross section and which flows out linearly is produced in each of the throughflow holes. 
         [0004]    EP 1 273 724 B1 (=DE 601 01 909 T2) has already disclosed a jet regulator having a jet regulator housing, in the housing interior of which there is provided a perforated plate with throughflow holes which have a clear cross section which remains constant in the throughflow direction. Positioned downstream of the perforated plate in the throughflow direction is an impingement cone which forms a constriction in the throughflow cross section of the already known jet regulator. The individual jets generated in the perforated plate can entrain the ambient air in the housing interior of the jet regulator housing, and subsequently impinge on the oblique surface of the impingement cone such that the aerated individual jets with the entrained air are broken up and thoroughly mixed. 
         [0005]    The already known jet regulators however require a certain throughflow rate and an adequate water pressure in the supply main network in order for there to be generated on the outflow side of the perforated plate, which serves as a jet splitter, a negative pressure sufficient to draw ambient air into the housing interior of the jet regulator housing. By contrast, the negative pressure generated in the case of a low throughflow rate and low water pressures is normally not sufficient to mix the ambient air with the through-flowing water. 
       SUMMARY 
       [0006]    It is therefore the object to provide a jet regulator of the type mentioned in the introduction which, even in the case of a low throughflow rate and/or low water pressures, such as are commonly desirable for example also for water-saving purposes, can generate an adequately aerated and accordingly sparkling, soft water jet. Here, it is also sought to generate as voluminous a jet as possible which, for the user, does not differ visually and haptically from the familiar prior art, wherein the jet regulator according to the invention should preferably be interchangeable with known jet regulator designs. 
         [0007]    This object is achieved according to the invention, in the case of the jet regulator of the type mentioned in the introduction, in particular in that at least one throughflow hole widens in a tapered or conical manner toward its outflow side. 
         [0008]    The jet regulator according to the invention has a jet regulator housing, in the housing interior of which there is provided a perforated plate which extends, for example, over the housing cross section. The perforated plate has a multiplicity of throughflow holes which are designed for splitting up the through-flowing water. At least one of the throughflow holes provided in the perforated plate widens toward its outflow side, and preferably progressively in tapered or conical fashion as far as the outflow side. Due to the tapered or conical spreading of the water emerging from the perforated plate, mixing of said water with the ambient air drawn into the jet regulator housing is possible practically over the entire housing cross section of the jet regulator housing even in the case of low throughflow rates and low water pressures. 
         [0009]    Here, the effective mixing of air with the through-flowing water is additionally promoted, even in the case of low throughflow rates and low water pressures, if at least one throughflow hole widens in a tapered or conical manner toward its outflow side such that the individual jet which emerges from the throughflow hole, and which widens due to the tapered shape or the conicity, mixes in the housing interior with the individual jet of at least one adjacent throughflow hole preferably before the individual jets impinge on at least one jet-forming part arranged in the housing interior. 
         [0010]    In addition to or instead of the widening of at least one throughflow hole in a tapered or conical manner, a further proposal according to the invention which is independently worthy of protection provides, in the case of the jet regulator of the type mentioned in the introduction, that on the outflow side of the perforated plate, flow obstructions are provided in the jet regulator housing and/or on the outflow face surface of the jet regulator housing, which flow obstructions are arranged or concentrated there in a central or middle region and divert the through-flowing water into an outer annular zone which, by contrast, has no flow obstructions or a smaller number or total area of flow obstructions. To provide the jet regulator with a jet regulator housing which, for compatibility reasons, corresponds in terms of its dimensions to the dimensions of commercially available jet regulators, and to nevertheless even in the case of low throughflow rates form a water jet which appears similarly voluminous in cross section, the through-flowing water is, by means of the flow obstructions, at least partially also diverted from a central or middle region into an outer annular zone which forms the outer circumference of the emerging water jet. 
         [0011]    An advantageous exemplary embodiment of the invention provides that, on the outflow side of the perforated plate and at a distance from the latter, there is provided on the housing inner circumference an encircling impingement bevel which narrows the clear housing cross section in said region progressively in the flow direction. In the case of this advantageous embodiment, the water which emerges from the throughflow holes and which has already been enriched with air impinges, at a distance downstream of the perforated plate, on an impingement bevel by means of which the water already thus treated is additionally mixed and split up, before the water thus enriched with air can emerge from the jet regulator as a homogenous, non-sputtering and sparkling, soft water jet. 
         [0012]    An embodiment of the invention which is particularly easy to produce provides that the impingement bevel forms the inflow side of a wall section which is formed as at least one constriction which undulates as viewed in longitudinal section. 
         [0013]    Here, the impingement bevel may be in the form of a protuberance on the inner circumference, or projection on the inner circumference, of the housing circumferential wall, and may be integrally connected to the jet regulator housing or to a jet regulator housing part. 
         [0014]    What is preferable, however, is an embodiment in which the impingement bevel is formed as a wall section of an annular or sleeve-shaped insert part that can be inserted into the jet regulator housing. 
         [0015]    In order also that at least one jet-forming part can be inserted into the housing interior of the jet regulator housing even if the perforated plate, which serves as a jet splitter, is formed integrally on the jet regulator housing, it is advantageous for the jet regulator housing to be of multi-part form and to have at least two housing parts which are preferably detachably connectable to one another. 
         [0016]    Here, particularly advantageous embodiments of the invention provide that the impingement bevel is formed integrally on the housing inner circumference of an outflow-side housing part, and/or that the perforated plate is formed integrally in the housing interior of an inflow-side housing part. 
         [0017]    In addition to or preferably instead of an impingement bevel, it is possible for at least one mesh or grate structure to be positioned downstream of the perforated plate as viewed in the flow direction. The water which emerges in tapered or conical form from the throughflow holes and which impinges on the at least one mesh or grate structure is slowed there and dispersed with the adjacent split-up parts of the water emerging from the adjacent throughflow holes, before subsequently emerging from the jet regulator as a soft overall jet. 
         [0018]    Although a grate structure of said type may also be formed by an inserted metal screen which is formed from two sets of metal wires interwoven preferably at right angles to one another, an embodiment is preferable in which the mesh or grate structure is formed from two sets of webs which intersect one another at intersection nodes. Such a mesh or grate structure formed from two sets of webs which intersect one another at intersection nodes can be produced in a simple manner even as a plastic injection-molded part. 
         [0019]    Here, a preferred embodiment of the invention provides that the at least one mesh structure positioned downstream of the perforated plate as viewed in the flow direction is formed from radial webs and from concentric webs which intersect said radial webs at intersection nodes. 
         [0020]    To yet further promote the splitting-up of the water passing from the perforated plate, it may be advantageous for at least two mesh or grate structures which are spaced apart from one another to be positioned downstream of the perforated plate as viewed in the flow direction. 
         [0021]    Here, one preferred refinement of the invention provides that at least one throughflow hole is aligned, in the flow direction, with a radial web of one mesh structure and with a concentric web of an adjacent mesh structure. 
         [0022]    The water that is split up in the perforated plate flows out of the throughflow holes of the perforated plate less as an individual jet and more as a spray cone. To break up and divide up the spray cones emerging from the throughflow holes yet further, it is advantageous for the webs that are aligned in each case with a throughflow hole to overlap or intersect, in the flow direction of the at least one throughflow hole, in the different planes of said mesh or grate structures. 
         [0023]    To make it possible for the jet regulator according to the invention to be produced with relatively little outlay for example from individual plastics parts, it may be advantageous for each mesh or grate structure to be formed by an insert part that can be inserted into the housing interior of the jet regulator housing. 
         [0024]    Here, one preferred embodiment provides that each insert part has, on the outer circumference, an encircling annular wall on which webs of the mesh or grate structure are held and preferably integrally formed. 
         [0025]    The breaking-up and splitting-up of the spray cones emerging from the throughflow holes of the perforated plate is further promoted if at least the concentric webs and preferably also the radial webs of an upstream mesh structure as viewed in the flow direction have an identical or smaller web thickness in relation to the webs of a mesh structure which is adjacent at the outflow side as viewed in the flow direction. 
         [0026]    The throughflow holes provided in the perforated plate may be arranged on concentric hole circles. However, a preferred embodiment of the invention provides that the perforated plate has a central, hole-free impingement surface which is bordered by at least one annular wall, that the at least one annular wall has passage openings oriented in the radial direction, and that in each case one throughflow hole of the perforated plate is provided on that side of the throughflow openings which is arranged in the impingement surface plane. The water which, in this way, is diverted in the region of the annular wall is initially slowed, diverted to the side and mixed by way of partial flows —flowing toward one another, if appropriate in opposite directions, before said water can flow through the throughflow holes of the perforated plate and emerge, on the outflow side of the perforated plate, in the form of a corresponding number of spray cones. 
         [0027]    In order that the water which is mixed with ambient air, and correspondingly made turbulent, in the housing interior of the jet regulator housing is formed into a homogenous overall jet again at the outflow side of the jet regulator, and in order that the water emerging from the jet regulator can be formed into a non-sputtering emerging water jet in an outflow-side homogenizing device, it is expedient if the outflow-side face surface of the jet regulator housing is formed by a mesh or honeycomb structure, and if the mesh or honeycomb structure that forms the outflow-side face surface is either non-detachably connected to, and in particular formed integrally with, the jet regulator housing or formed by an insert part that can be inserted into the jet regulator housing. 
         [0028]    The homogenisation of the overall jet emerging from the jet regulator is further promoted if the mesh or honeycomb structure that forms the outflow-side face surface of the jet regulator housing is formed by webs which, at least in an outflow-side sub-region, narrow in the flow direction. 
         [0029]    A preferred refinement of the invention provides that the jet regulator according to the invention is designed as an aerated jet regulator, into the housing interior of which there issues at least one aeration opening which connects the housing interior to the atmosphere. In order that the at least one aeration opening can connect the housing interior to the atmosphere, it is possible for at least one aeration duct which is designed to be open to the atmosphere to be provided in a double-walled sub-region of the jet regulator housing or in an annular gap bordering the jet regulator housing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    Refinements of the invention will emerge from the claims in conjunction with the figures and the description of the figures. The present invention will be described in more detail below on the basis of preferred exemplary embodiments. 
           [0031]    In the figures: 
           [0032]      FIG. 1  shows, in a perspective partial longitudinal section, a jet regulator which, on the outer circumference of its jet regulator housing, bears an external thread by means of which the jet regulator can be detachably screwed into an internal thread on the water outlet of a sanitary outlet fitting, 
           [0033]      FIG. 2  shows the jet regulator from  FIG. 1  in a longitudinal section, wherein it is possible in the housing interior of the jet regulator housing to see a perforated plate which is integrally connected to an inflow-side housing part and which bears throughflow holes which widen in a tapered or conical manner toward the outflow side of the perforated plate, 
           [0034]      FIG. 3  shows the jet regulator from  FIGS. 1 and 2  in a longitudinal section through section plane III-III from  FIG. 2 , wherein, through the throughflow holes of the transversely sectioned perforated plate, it is also possible to see the structures downstream of the perforated plate, 
           [0035]      FIG. 4  shows a detail of the cross-sectional illustration shown in  FIG. 3  in the region of a throughflow hole of the transversely sectioned perforated plate, 
           [0036]      FIG. 5  shows the jet regulator from  FIGS. 1 to 4  in an exploded perspective illustration of its individual parts, 
           [0037]      FIG. 6  shows a jet regulator of similar design to the jet regulator as per  FIGS. 1 to 5 , wherein the jet regulator shown in  FIG. 6  can be mounted on the water outlet of a sanitary outlet fitting with the aid of an outlet mouthpiece not shown in any more detail here, and wherein the outflow-side face surface of the jet regulator shown in  FIG. 6  is formed by an insert part which can be inserted into the jet regulator housing and which has a mesh structure, 
           [0038]      FIG. 7  shows the inflow-side view of a further jet regulator, wherein said inflow-side view shows primarily an upstream or filter screen positioned upstream of the jet regulator at the inflow side, 
           [0039]      FIG. 8  shows the jet regulator from  FIG. 7  in a longitudinal section through section plane VIII-VIII from  FIG. 7 , wherein it can be seen that the jet regulator shown in  FIG. 8  has an impingement bevel which is spaced apart from the outflow side of the perforated plate and which forms a constriction that narrows the clear throughflow cross section of the jet regulator in the flow direction, 
           [0040]      FIG. 9  shows the perforated plate of the jet regulator shown in  FIGS. 7 and 8  in a perspective partial longitudinal section, 
           [0041]      FIG. 10  shows the outflow-side face surface of the jet regulator shown in  FIGS. 7 to 9  in a view from below, 
           [0042]      FIG. 11  shows the jet regulator as per  FIGS. 7 to 10  in an exploded perspective illustration of its individual parts, 
           [0043]      FIG. 12  shows the jet regulator from  FIGS. 7 to 11  in an enlarged longitudinal section, wherein the flow direction of the water —flowing through the jet regulator is indicated by corresponding arrows, and 
           [0044]      FIG. 13  shows, in an enlarged perspective partial longitudinal section, the perforated plate of the jet regulator shown in  FIGS. 7 to 12 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0045]      FIGS. 1 to 13  show three exemplary embodiments  1 ,  10 ,  100  of a jet regulator. The jet regulator embodiments  1 ,  10 ,  100  are designed to be mounted on the water outlet of a sanitary outlet fitting in order to form a homogenous and laterally non-sputtering water jet there. In order that the water jet can emerge as a sparkling, soft water jet, the jet regulator embodiments  1 ,  10 ,  100  are in the form of aerated jet regulators in which the through-flowing water is mixed and enriched with ambient air. 
         [0046]    The jet regulator embodiments  1 ,  10 ,  100  have a sleeve-shaped jet regulator housing  2  of circular cross section. The jet regulator embodiment  1  shown in  FIGS. 1 to 5  has, on the housing outer circumference of the jet regulator housing  2 , an external thread  3  which interacts with an internal thread arranged on the inner circumference of the water outlet of the outlet fitting (not shown in any more detail here). Here, the jet regulator embodiment  1  illustrated here can be screwed into the water outlet such that the outflow-side face surface of the jet regulator housing  2  is arranged practically in a plane with the outflow-side face edge of the outlet fitting. 
         [0047]    By contrast, the jet regulator embodiments  10 ,  100  shown in  FIGS. 6 to 13  are designed for being mounted on the water outlet of the outlet fitting by means of a sleeve-shaped outlet mouthpiece (not illustrated in any more detail here) after the jet regulator  10 ,  100  has been inserted, from the inflow-side sleeve opening of the outlet mouthpiece, into the sleeve interior of the latter until an annular shoulder  4  on the outer circumference of the jet regulator housing  2  lies against a support arranged on the inner circumference in the outlet mouthpiece. 
         [0048]    In the housing interior of the jet regulators  1 ,  10 ,  100  there is provided a perforated plate  5  which bears a multiplicity of throughflow holes  6 . At least one throughflow hole  6  and preferably all of the throughflow holes  6  of the perforated plate  5  widen in a tapered or conical manner toward their outflow side at least in an outflow-side sub-region. The throughflow holes  6  provided in the perforated plate  5  are designed for splitting up the through-flowing water. Due to the tapered or conical spreading of the water emerging from the perforated plate, mixing of said water with the ambient air drawn into the jet regulator housing is possible practically over the entire cross section of the jet regulator housing  2  even in the case of low throughflow rates and low water pressures. 
         [0049]    Here, the throughflow holes  6  widen in a tapered or conical manner such that the water jet which emerges from the throughflow holes  6  and which widens due to the tapered shape or the conicity mixes in the housing interior with the individual jet of at least one adjacent throughflow hole before the individual jets impinge on at least one jet-forming part arranged in the housing interior. 
         [0050]    To make it possible for the through-flowing water to be additionally split up and mixed with ambient air, it is the case in the jet regulator embodiments  1 ,  10  shown in  FIGS. 1 to 6  that at least one, and preferably at least two, mesh structure(s) is/are positioned downstream of the perforated plate  2  in the flow direction, said mesh structure(s) being formed from radial webs  7  and from concentric webs  9  which intersect said radial webs at intersection nodes  8 . 
         [0051]    In  FIGS. 3 and 4 , it can be seen by way of example that at least one throughflow hole  6  and preferably all of the throughflow holes  6  is/are aligned, in the flow direction, with a radial web  7  of one mesh structure, in this case of the mesh structure that is downstream in the flow direction, and with a concentric web  9  of an adjacent mesh structure, in this case of the mesh structure arranged at the inflow side. The webs  7 ,  9  which are each aligned with one of the throughflow holes  6  overlap or intersect here, in a central or middle region of the associated throughflow hole  6 , in the different planes of said mesh structures. 
         [0052]    From a comparison of  FIGS. 2 ,  5  and  6 , it is clear that each of the mesh structures, which together form a jet regulating device, is formed by an insert part  11 ,  12  that can be inserted into the housing interior of the jet regulator housing  2 . Here, each of said insert parts  11 ,  12  has, on the outer circumference, an encircling annular wall  13 , wherein the radial webs  7 , which intersect the concentric webs  9 , of the mesh structure are connected to, and in this case formed integrally with, said encircling annular wall. 
         [0053]    It can be seen particularly clearly from  FIG. 4  that at least the concentric webs  9  and preferably also the radial webs  7  of a mesh structure positioned upstream as viewed in the flow direction have a greater web thickness than the webs  9 ,  7  of a mesh structure situated adjacently at the outflow side as viewed in the flow direction. In this way, as viewed in the throughflow direction, each throughflow hole  6  in the perforated plate  5  appears to split up into a multiplicity of further, smaller throughflow openings. 
         [0054]    From a comparison of  FIGS. 2 ,  5 ,  6 ,  8  and  9 , it can be seen that the perforated plates  2  provided in the jet regulator embodiments  1 ,  10 ,  100  have a central impingement surface  14  which is bordered by at least one annular wall  15 . This annular wall  15  has passage openings  16  which are oriented in the radial direction and which, in this case, are arranged spaced apart from one another around the circumference of the annular wall  15 . A respective one of the throughflow holes  6  of the perforated plate  2  is provided at the base side, and thus on the side arranged in the impingement surface plane, of the passage openings  16 . As a result of this diversion of the in-flowing water in the region of the throughflow holes  6 , the water is slowed, diverted to the side and possibly mixed by way of partial flows flowing toward one another in opposite directions, before said water is subsequently subjected to an increase in speed again due to the constriction of the throughflow cross section in the throughflow holes  6 . In accordance with the Bernoulli equation, this speed increase results in a negative pressure being generated on the outflow side of the perforated plate  5 , by means of which negative pressure ambient air can be drawn into the housing interior of the jet regulator housing  2 . For this purpose, in the housing circumferential wall of the jet regulator housing  2 , there is provided at least one aeration opening  17  which opens into the housing interior on the outflow side of the perforated plate  5 . Outside the central impingement surface  14  there may be provided at least one further impingement surface  29 , which in this case is of encircling form at the outside and which is preferably arranged in the plane of the central impingement surface  14 . 
         [0055]    Whereas the at least one aeration opening  17  in the jet regulator embodiment  1  shown in  FIGS. 1 to 5  is in this case connected to the atmosphere via a double-walled section  18  of the housing circumferential wall on the outflow side of the jet regulator  1 , it is the case in the jet regulator embodiments  10 ,  100  shown in  FIGS. 6 to 13  that the aeration openings  17  extend through the jet regulator housing  2  in the radial direction and are connected, on the outside of the jet regulator housing  2 , to an aeration duct which is in the form of an annular gap between the housing outer circumference of the jet regulator housing  2  and the inner circumference of the outlet mouthpiece and which is open to the atmosphere at the outflow-side face side of the outlet mouthpiece and jet regulator  10 ,  100 . 
         [0056]    Instead of the insert parts  11 ,  12 , the jet regulator embodiment  100  shown in  FIGS. 7 to 13  has, on the outflow side of the perforated plate  2  and at a distance from the latter, an encircling impingement bevel  19  on the housing inner circumference, which impingement bevel narrows the clear housing cross section in said region progressively in the flow direction. This impingement bevel  19  is formed by the inflow side of a wall section formed as a constriction which undulates as viewed in longitudinal section. The wall section that has the impingement bevel  19  is in this case in the form of an annular or sleeve-shaped insert part  20  that can be inserted into the jet regulator housing  2 . 
         [0057]    From a comparison of  FIGS. 6 and 11 , on the one hand, and  FIG. 5 , on the other hand, it is clear that the outflow-side face surface of the jet regulators  1 ,  10 ,  100  is formed by a mesh structure  22  or a honeycomb structure  21 . Whereas the mesh or honeycomb structure  22 ,  21  that forms the outflow-side face surface of the jet regulators  1 ,  100  is non-detachably connected to the jet regulator housing  2 , the outlet structure  22  of the jet regulator  10  shown in  FIG. 6  is formed by an insert part  23  that can be inserted into the jet regulator housing  2 . From a comparison of  FIGS. 8 and 10 , it can be seen that the mesh structure  22  that forms the outflow-side face surface of the jet regulator  100  is formed by radial and concentric webs  24 ,  25  which narrow in the flow direction at least in an outflow-side sub-region. Homogenisation of the water emerging from the jet regulator housing  2  through the mesh structure so as to form a homogenous overall jet is additionally promoted by virtue of said webs  24 ,  25  narrowing in the flow direction at least in an outflow-side sub-region. 
         [0058]    In  FIGS. 10 and 11 , it is clear that, on the outflow side of the perforated plate, flow obstructions may be provided in the jet regulator housing and/or—as is the case here—on the outflow face surface of the jet regulator housing  2 , which flow obstructions are arranged or concentrated there in a central or middle region and divert the through-flowing water into an outer annular zone which, by contrast, has no flow obstructions or a smaller number or total area of flow obstructions. In the case of the jet regulator  100  shown in  FIGS. 10 and 11 , said flow obstructions are formed by the concentric webs  25  which, on the outflow face surface of the jet regulator housing  2 , are concentrated in a central or middle region, whereas an outer annular zone is free from such concentric webs. 
         [0059]    In  FIGS. 5 ,  6  and  11 , it is clear that the jet regulator housing  2  is formed in this case by two housing parts  26 ,  27  which are detachably connectable to one another and preferably lockable to one another and of which in this case the housing part  26 , which is upstream at the inflow side, is connected integrally to the perforated plate  6 . In order that any dirt particles entrained in the water cannot impair the correct functioning of the jet regulator, an upstream or filter screen  28  is positioned upstream of the jet regulator housing  2 , which upstream or filter screen is in this case held detachably on the inflow-side housing part  26 . This upstream or filter screen  28  has a multiplicity of filter or screen openings which are circular or polygonal, and in particular hexagonal, in cross section. 
       LIST OF REFERENCE SIGNS 
       [0000]    
       
         
           
               1  Jet regulator (as per  FIGS. 1 to 5 ) 
               2  Jet regulator housing 
               3  External thread 
               4  Annular shoulder 
               5  Perforated plate 
               6  Throughflow holes (in the perforated plate  5 ) 
               7  (Radial) webs 
               8  Intersection nodes 
               9  (Concentric) webs 
               10  Jet regulator (as per  FIG. 6 ) 
               11  (Inflow-side) insert part 
               12  (Outflow-side) insert part 
               13  Annular wall (on the insert parts  11 ,  12 ) 
               14  Impingement surface (centrally on the perforated plate  5 ) 
               15  Annular wall (on the inflow side on the perforated plate  5 ) 
               16  Passage openings (in the annular wall  15 ) 
               17  Aeration opening (in the jet regulator housing  2 ) 
               18  (Double-wall) section (of the housing circumferential wall) 
               19  Impingement bevel 
               20  Insert part (with impingement bevel  19 ) 
               21  Honeycomb structure (as outflow-side face surface of the jet regulator) 
               22  Mesh structure (as outflow-side face surface of the jet regulator) 
               23  Insert part (as outflow-side face surface of the jet regulator  10 ) 
               24  (Radial) webs (of the outflow-side face surface of the jet regulator  100 ) 
               25  (Concentric) webs (on the outflow-side face surface of the jet regulator  100 ) 
               26  (Inflow-side) housing part 
               27  (Outflow-side) housing part 
               28  Upstream or filter screen 
               29  (Externally encircling) impingement surface (of the perforated plate  5 ) 
               100  Jet regulator (as per  FIGS. 7 to 13 )