Abstract:
Device for pneumatically milking a cow, comprising a number of milk extractors, each comprising a teat cup as well as milk line connected to the lower end of the teat cup, which line leads from the teat cup to a collection chamber for the milk from the teat cup, each milk extractor being provided with a supply for a cleansing medium, such as a disinfectant, to the teat cup, in particular to a teat present in the teat cup, the supply comprising a line having an end portion with discharge end, and each milk extractor being provided with means for closing off the passage of the milk extraction at or downstream of the discharge end of the line for cleansing medium, preferably at that level, when discharging the cleansing medium, the closing means comprising a reciprocating closing body that can be moved between a position leaving the passage of the milk extractor free and a position closing it off, the closing body being provided with a squirt line forming the end portion with discharge end of the line for supply of cleansing medium, and being positioned to debouch into the milk extractor, particularly the milk line, when in the closing-off position

Description:
This application is a continuation of application No. PCT/NL01/00699, filed Sep. 21, 2001. 

   The invention relates to a milking device provided with cleansing means, in particular for cleansing/disinfecting the teat to which the milking device is connected. 
   BACKGROUND OF INVENTION 
   From German patent application 26 22 794 such a device and method are known. This document shows a milking device for pneumatically milking a cow and subsequent cleansing or disinfecting the teats of the cow&#39;s udder, with a system of four milk extractors, each comprising a teat cup which at one end is provided with an open lining and with the other end is connected to a milk line to a common milk collection chamber for the milk from the cow in question, each cup having a connection to a source of changing vacuum, and an outflow opening of a line for the supply of cleansing liquid being arranged in the wall of a teat cup. 
   When using this known device the method used is to first place the teat cups around the cow&#39;s teats, after which the cow is milked by means of the changing vacuum. After finishing milking the cow, while the cow&#39;s teats are still in the teat cups, a certain quantity of cleansing liquid is squirted into the teat cup by means of a pump. Said liquid will disinfect the teat and the space in the teat cup, but will subsequently together with the milk residue in the teat cup deposit on the inner wall of the teat cup. The liquid will then have the chance, even before the teat cups have been removed from the teats, to go back past the inner wall or from the teat back down and thus partially end up in the milk line. As a result milk residues of a cow will not only be left in the teat cup and milk line but will thus also transfer a contamination from the one cow to the other. Moreover, when milking the next cow residues of the cleansing liquid that have ended up in the milk line will subsequently end up in the central milk storage to which it is connected and therefore in the milk to be delivered. 
   A number of suggestions for improvements of this have been described in applicant&#39;s earlier International patent application WO 99/66787. In both of these suggestions use is made of a leaf spring, which in the unloaded situation abuts the inner surface of the milk extractor and then closes off a supply chamber for cleansing medium, and which in a loaded situation closes off the passage in the milk extractor to the downstream portion thereof and clears the way for supplied pressurized (by compressed air) cleansing medium. In that way when discharging a cleansing medium, and the aforementioned problem therefore exists, it is counteracted that during discharging the cleansing medium said medium may end up in the milk line and thus in the milk collection chamber. In a first embodiment, the spring leaf is operated by means of a pusher, which is connected to a separate pressure line. 
   In a second embodiment, which is simpler as to construction, the leaf spring is directly operated by the pressure of the cleansing medium itself. 
   SUMMARY OF INVENTION 
   It is an object of the invention to improve on this. 
   A further object of the invention is to provide a milking device, with which in a reliable or positive manner a closure can be realised and maintained for and during discharging cleansing liquid in a milk extractor, particularly teat cup and contiguous line portion. 
   A further object of the invention is providing a milking device, with which it can almost entirely be ruled out that cleansing medium is discharged before the closing of the passage is completed as a result of which cleansing medium might otherwise end up in the milk. 
   A further object of the invention is a device of the kind mentioned in the preamble with which in a reliable manner cleansing medium cannot be discharged until the passage in the milk extractor is closed off. 
   At least one of these objects is achieved according to the invention with a device for pneumatically milking a cow, comprising a number of milk extractors, each comprising a teat cup as well as a milk line connected to the lower end of the teat cup, which leads from the teat cup to a collection chamber for the milk from the teat cups, each milk extractor being provided with a supply for a cleansing medium, such as a disinfectant, to the teat cup, in particular to a teat present in the teat cup, the supply comprising a line having an end portion with discharge end, and each milk extractor being provided with means for closing off the passage of the milk extractor at or downstream of the discharge end of the line for cleansing medium, preferably at that level, when discharging the cleansing medium, the closing means comprising a movable closing body that can be moved between a position leaving the passage of the milk extractor free and a position closing it off, the closing body being provided with a squirt line forming the end portion with discharge end of the line for supply of cleansing medium and being positioned to debouch into the milk extractor, in particular the milk line, when in the closing position. 
   By accommodating the end portion of the supply line of cleansing medium in the closing body the mutual position of them both is fixed and known. With known movement of the closing body it can be ensured in a simple manner by suitable selection of the location of the discharge opening of the squirt line that the discharge can take place at the correct moment with, an actually closed off passage. 
   Preferably the device is provided with means for pneumatically moving the body. The device may comprise a compressed air connection to the supply line for the supply of cleansing medium. In an embodiment, said compressed air line may be used for the movement of the closing body. In another embodiment these functions may be separated, in two separately operable pressure lines. 
   In a first further development of the device according to the invention the closing body is movable between the free position and a closing position by means of a reciprocating movement, 
   A simple failure-free embodiment is one in which the closing body is formed by a—preferably free—piston that is bearing mounted in a sliding manner in a chamber debouching in the milk extractor and preferably is positioned transverse to it. A free piston is easy to manufacture and mount, and moreover takes up little length of place. 
   In case the piston is a free piston it can advantageously be provided at its inner end with a duct in which a fixed pin extends, the duct being part of the squirt line. The pin cannot only form a guidance means for the piston, but also ensure a relative closing of the duct and thus the squirt line during the (fast) pressure build-up in the end chamber and the movement of the piston. 
   At its inner end the piston may be provided with a sealing for sealing against the inner surface of the chamber, a supply line for at least compressed air debauching in the chamber in its portion opposite the inner side of the piston. Alternatively or additionally the chamber near the connection to the milk extractor can be provided with a sealing for sealing engagement of the piston&#39;s circumference, at the side of the piston facing away from the milk extractor. Thus pressure build-up and the subsequent movement of the piston can take place in the chamber, without leakage of cleansing medium. 
   The piston may have a circular cross-section, the duct being arranged eccentrically in the piston, as a result of which undesirable rotation of the piston (and thus of the discharge opening) is counteracted. Alternatively rotation of the piston may be prevented by using a piston of a cross-section that is not round. The chamber and milk extractor passages are then complementary fittingly formed. 
   The piston is arranged/indexed to always discharge the cleansing medium in the correct direction when cleansing. 
   The device can also be used for rinsing the milk extractor, upstream of the closing of the milk line, when it is further provided with means for passage of water, particularly in the form of a pulsating water/air mixture, through the supply line to the discharge end. 
   The piston may also have a narrowed portion, situated at radial distance from the inner surface of the chamber, the sealing provided at the chamber engaging about the narrowed piston portion. As a result a space is created which when necessary is easy to clean or rinse, as will be explained later. Furthermore a space is created for a possible (coil) spring. 
   Preferably said sealing is a ring having a sealing lip oriented to the chamber inner side, as a result of which it is prevented that residues of particularly the cleansing medium that are at the inner side of the sealing, are sucked towards the milk line during milking as a result of the pulsating vacuum in said line. 
   Preferably the discharge opening in the piston is substantially radially oriented, preferably in a direction substantially parallel to the passage of the milk extractor and towards the teat cup. 
   In case the piston, in the retracted, free position, opens with the discharge opening at the inner side of the sealing, and the sealing is active around a piston end situated outside of it, it is prevented that during milking possible residues in the discharge opening are sucked into the milk line. 
   Preferably the piston is provided with a recess, duct or the like, on a portion at the inner side of the discharge opening, for fluid communication in the closed-off position of the space in the milk extractor upstream of the closing body and the chamber. As a result cleansing medium, that falls back onto the piston and—because of the closing—cannot go further into the milk line, can run down to the chamber, which to that end preferably is provided with drainage holes. 
   In a simple constructive manner the recess can be a levelling in the surface of the piston. 
   It is further preferred that the milk extractor is provided with a chamber for fitting accommodation of the end of the closing body in a position completely closing off the milk extractor, so that it is once more additionally prevented that cleansing medium flows past the closing body. Furthermore the milk extractor can-be provided in the inner surface with means for guiding the closing body, so that the action of the piston is further improved. 
   In a further embodiment the device is furthermore provided with means, such as a spring, for biassing the closing body in the closing-off, cleansing position towards the free, milking position (also see above). Thus it can be ensured that the piston/the closing body moves back to the starting position, in which the passage is free, particularly immediately after discharge of cleansing medium has been stopped. Alternatively use can be made of putting the line for the cleansing medium on a vacuum. 
   In a first further development of the device according to the invention the pin has a passage for—preferably permanent—fluid communication of the duct to the supply line, the means for pneumatically moving the body also being formed by a pressurized air or compressed air line separate from the supply line. It is then prevented that cleansing medium ends up at the inner side of the piston. 
   In an alternative further development the means for pneumatically moving the body are also formed by the pressurized cleansing medium. When the said pin, but then without passage, is used, it may be shortened, so that it closes off the duct in the piston in a first section and then no discharge of cleansing medium from the squirt line takes place. When the piston is in the closing position the pin will have come out of the opening of the duct, so that pressurised cleansing medium will go through the duct in the piston and will squirt out of the discharge opening. It is preferred here that the discharge opening is situated at such a distance from the end of the closing body that it is not released in the passage of the milk extractor until the body has closed off the passage of the milk extractor completely. 
   In an alternative embodiment the closing body is movable between the free position and the closing-off position by a rotational movement. The closing body can then be provided with a milk passage which in the free position is in open line with the milk flow paths in the milk extractor. The rotation can take place about an own axis of the closing body, particularly transverse to the milk line. 
   From a further aspect the invention provides a device for milking a cow, comprising a number of milk extractors, each defining a milk passage and comprising a teat cup as well as a milk line connected to the lower end of the teat cup, which line leads from the teat cup to a collection chamber for the milk from the teat cups, each milk extractor being provided with a supply for a cleansing medium, such as a disinfectant, to the teat cup, in particular to a teat present in the teat cup, the supply having a discharge nozzle, which is a part of a closing body for the milk passage, which closing body is movable between a position leaving the milk passage of the milk extractor free and a position closing it off, the discharge nozzle being positioned to debouch into the milk extractor, in particular the milk line, when in the closing position. 
   In all preceding embodiments the end portion of the discharge end or the discharge nozzle can advantageously be positioned to be closed off from either the milk extractor or the milk passage when in the free position. 
   In a very simple and easy to place—also afterwards—embodiment, the closing means are accommodated in a coupling piece which is accommodated in the milk extractor, preferably near the transition between the teat cup and the (flexible) milk line. 
   The invention also relates to such a coupling piece, as well as to an assembly of a number of devices according to the invention and a central milk storage connected to the milk collection chamber. 
   From a further aspect the invention provides a method for milking a cow, the milk discharge being closed off after milking by moving a closing body from a position keeping the milk discharge open to a position keeping the milk discharge closed off, cleansing medium being discharged via the closing body, by squirting in the milk discharge towards the teat cup, the teat cups being released, and while keeping the closing body in the closed off position, squirting a pulsating water/air mixture via the closing body for rinsing the milk extractor. 
   Preferably when the teat cups are still attached to the cow, in the closed position of the closing body, cleansing medium falling back on the closing body is deflected from the side of the closing body facing the teat cup to a chamber, particularly a chamber in which the closing body can be accommodated in the open position. 
   Preferably the closing body is subsequently moved to the open position, in which the chamber is sealed with respect to the milk discharge, and subsequently a water/air mixture is discharged again via the closing body, for rinsing the chamber, the rinsing liquid escaping via drainage holes. 
   Thus it is ensured with simple means that no residues of cleansing medium are left behind. 
   From a further aspect the invention provides a device for pneumatically milking a cow, comprising a number of milk extractors, each comprising a teat cup as well as a milk line connected to the lower end of the teat cup, which line leads from the teat cup to a collection chamber for the milk from the teat cups, each milk extractor being provided with a supply for a cleansing medium, such as a disinfectant, to the teat cup, in particular to a teat present in the teat cup, the supply comprising a line debouching in the milk extractor, in particular the milk line, at the location of a discharge end, and each milk extractor being provided with means for closing off the passage of the milk extractor at or downstream of the discharge end of the line for cleansing medium, preferably at that level, when discharging the cleansing medium, the closing means comprising a reciprocating closing body which in the discharge end can be moved between a position leaving the passage of the milk extractor free and a position closing it off, the closing body being provided with a squirt line forming the end portion of the line for the supply of cleansing medium. 
   Below the invention will be further elucidated on the basis of two exemplary embodiments shown in the attached drawings, in which: 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a device according to the invention arranged under a cow; 
       FIGS. 2A and 2B  show cross-sections in isometric view of a first embodiment of a coupling piece according to the invention, in the milking position and in the cleansing position, respectively; and 
       FIGS. 3A and 3B  show cross-sections of a piston in the coupling piece of the  FIGS. 2A and 2B , in the milking position and in the cleansing position, respectively. 
       FIGS. 4A-C  show a second embodiment of a coupling piece according to the invention, a cross-section in disassembled situation, a detail of a sealing ring in it, and a top view of the chamber part of the coupling piece, respectively; 
       FIGS. 5A and 5B  show the coupling piece of  FIGS. 4A-C  in milking position and cleansing position, respectively; 
       FIGS. 5C and 5D  show the coupling piece of  FIGS. 4A-C  in milk line rinsing position and chamber rinsing position, respectively, and; 
     FIGS.  6 A,B and  6 C,D show a third possible embodiment of a coupling piece for a device according to the invention, wherein the coupling piece is shown in the milking position and the cleansing position, respectively, in (partial) cross-sections in two longitudinal planes perpendicular to each other. 
   

   DETAILED DESCRIPTION 
     FIG. 1  shows a cow of which only the hind legs have been drawn with an udder  2  and four teats  3 , in which a device  1  according to the invention has been arranged under the teats  3  of the udder  2  of the cow. 
   The device  1  for pneumatically milking the cow comprises four milk extractors, which each comprise a teat cup  5  and a milk line  6 , in which between the teat cup  5  and the milk line  6  a coupling piece  4  according to the invention has been arranged. The milk lines  6  supply the milk to a milk collection chamber  7 , from where the milk is transported to a central storage via a common discharge line  25 . Each teat cup  5  is connected via a line  8  to a source of changing vacuum, by means of which the milking is carried out. Each coupling piece  4  is provided with a supply line  9 , which is connected to a manifold  10  for cleansing liquid, such as iodine, which is supplied via a line  11 . Via the line  12  the air is supplied under pressure to the manifold  10  in order to blow the liquid under the influence of the pressure of the air into the teat cup. 
   The coupling piece  4  shown in  FIG. 2A  has a housing  14  made of synthetic material, having a connection end  16  to which the teat cup  5  can be connected, and a discharge end  17 , to which the milk line  6  can be connected. The housing  14  forms a passage  15  for milk coming from the direction A, so that it may continue flowing from the teat cup to the milk line  6 . 
   The coupling piece  4  is provided with extension  18 , in which a chamber  19  is formed, in which a free piston  23  has been accommodated. The chamber  19  has been provided with a connecting nipple  30  for the line  9 . The piston  23  is straight circle-cylindrical and provided with a flat end  23   a  and an inner end  23   b  widened with flange  24 . At the inner end  23   b  a duct opening  26  is situated eccentrically with respect to the circle-cylindrical body of the piston  23 , in which opening a pin  27  extends, which with widened head  28  is secured in the wall  18   a . The flange  24  leaves a slit space open with respect to the inner surface of the chamber  19 . 
   Where the chamber  19  debouches in the passage  15  a ring shoulder  33  and a sealing ring  22  have been accommodated in the wall of the housing  14 . Said sealing ring  22  sealingly engages the outer surface of the piston  23 , but makes movement along it possible. 
   As indicated in  FIG. 3A  the piston  23  is internally provided with a duct  31  extending in axial direction, which duct near its bottom merges in radial direction in a little duct  32 , which ends in discharge opening  29 . The eccentricity of the duct  31  and of the pin  27  is such that the discharge opening  29  and the little duct  32  are oriented parallel to the centre line of the passage  15 , and will remain so. The pin  27  fits (very) snugly in the duct  31 . When milking has ended and the teat cups  5  are still around the teat of the cow, control means that are not further shown pressurize the line  9  with a mixture of air and cleansing medium. Via connecting nipple  30  it (B) enters chamber  19 , as considered in the drawing below the flange  24 . The connecting nipple  30  may alternatively also be arranged in the upper wall of the chamber  19  as considered in the drawing, but the exemplary embodiment shown is more efficient in the use of space and line length. The line  9  will after all first extend from below upwards. 
   The pressure prevailing in the line  9  will also be present at the inner surface  23   b  of the piston  23 . As a result the piston  23  will be slid out of the chamber  19 . During the movement of the end  23   a  transversely, through the passage  15 , the piston  23  is guided on both sides by guidance grooves  21  made in the wall of the housing  14 . The movement of the piston  23  will take place very quickly, in which it should be considered that the pressure used could be approximately 5 Bar. Finally the end  23   a  end up in the cavity  20 , in which it is accommodated in a snugly fitting manner. At that moment the pin  27  has come out of the duct  31 . The surface of the smallest passage of the duct  31 /little duct  32  is smaller than the one of the nipple  30 , so that no discharge will take place before the piston  23  has moved out completely. The discharge opening  29  has then just become exposed in the passage  15 , which further contributes to the prevention of premature discharge. The pressure prevailing in the chamber  19  can no longer have the effect that the piston  23  moves further, so that said pressure is entirely used for discharging cleansing medium, via chamber  19 , access  26 , duct  31 , little duct  32  and finally discharge opening  29  in the direction C, towards the teat cup  5 . The piston  23 , a kind of sliding cock as it were, here completely closes off the passage  15 , so that there is no danger that cleansing medium ends up in the milk line  6 . The fitting of the piston between the grooves  21  and the cavity  23  is so snug, that the—intended—operation movement of the piston is possible, though that leakage of liquid past the piston is prevented. 
   Then the teat cups are removed from the teats but the pressure in line  9  is still maintained, until the milk cups are situated in hanging position, so that the cleansing liquid can leak out of the teat cups. 
   After a short while the pressure in the line  9  is released, after which the piston  23  can move again to the initial position, the milking position, under influence of a spring  25 , which under the influence of the pressure in the chamber  19  was kept pressed in between the flange  24  and the ring  33 . Instead of the spring  25  the line  9  can be put on vacuum B′, in order to thus, as it were, suck back the piston  23 . During milking said vacuum B′ is then maintained. 
   The coupling piece  104  shown in  FIGS. 4A-C  corresponds to some extent to the coupling piece  4  discussed above, though differs from it on some points. As can be seen in  FIG. 4A  there is question here of a housing  114  made of synthetic material, having a passage  115 , a connection end  116  and a discharge end  117 . A circular collar  139  is formed on the housing  114 , the collar having a passage  170  that is transverse to the passage  115  and is in open connection to it. The passage  170  is limited by a shoulder  133  and an edge  134  above it, on which a sealing ring  122  is placed. Said sealing ring  122  is further shown in  FIG. 4B , and has an outer ring  156 , which to the inside merges in a wedge-shaped lip  155  that is formed as a unity with it. The ring  155  is able to deform in the direction M for the sealing. The ring  122  is made of suitable rubber material, in which metal reinforcement rings  156   a  and  156   b  have been integrally formed. The top side of the ring  156  forms a shoulder  161 , on which a metal support ring  160  may come to lie. Said metal support ring  160  forms a stop for the pressure spring  125  (FIG.  5 A), and also protects the ring  122  against damage by the spring. 
   The housing  114  is furthermore provided with a transverse guidance  140 , that is formed complementary to the free piston  123  yet to be discussed. Said recess  140  is situated at two diametrically opposite sides of the inner wall of the passage  115 . In the wall portion that is situated opposite the passage  170  a shallow recess  120  is formed, for accommodation of the end of the piston  123 , in the cleansing position. 
   The free, in this example substantially straight circle cylindrical piston  123  is provided with a duct  131  extending in axial direction, that is turned at right angles to a little duct  132 , that ends in discharge opening  129 . In the widened inner end  123   a  of the piston  123  a shoulder  151  is formed in the duct  131 , for accommodation of an O-ring  152 . Above it a passage  150  is situated, in which pin  127  yet to be discussed can easily be inserted. At the circumference of the widened inner end  123   a  of the piston  123  a shoulder  185  is situated and above it a circumferential groove  152 , in which an O-ring  153  is placed. As can be seen in  FIG. 4A  the piston  123  has a narrowed portion  123   b  below the widened inner end  123   a . In the narrowed portion  123   b , at one side, at the side where the sealed opening  129  is situated, a flat surface  180  is arranged forming a recess with respect to the circumference of the narrowed portion  123   b.    
   In the upper part of  FIG. 4A  the extension  118  is shown forming a straight circle cylindrical chamber  119 , and at the lower end or outer end being provided with a collar  138 , that snugly fits in the edge  134  also lying on support ring  160 . The extension  118  can be glued to the housing  114  and/or by means of screws (not shown) that are to be inserted into holes  163   a,b.    
   Fixedly attached in the extension  118  is a pin  127 , forming a continuous duct  127   a , that is in communication with the supply hose  109   a , for, at choice, compressed air, water and cleansing medium, such as iodine. As can be seen in  FIG. 4C  said line  109   a  ends in connection  130   a  eccentrically with respect tot he chamber  119 , and thus the pin  127  is also eccentric, just like in the example discussed earlier. A difference now is that here a separate line  109   b  is present for compressed air, with which in the assembled situation, a delivery pressure can be put on the top side or inner side of the piston  123 —via centric connection  130   b— , for axial movement of the piston  123 . Said pressure hits the inner surface of the widened head  123   a  of the piston  123 , and said pressure cannot leave as a result of the O-ring  153 . 
   At the opposite side the extension  118  is further provided with drainage holes or drainage slits  141   a ,  141   b , that open in the free atmosphere. 
   In  FIG. 5A  the situation immediately after milking is shown. The last milk has flown down in the direction A. Then compressed air from the direction D is supplied via line  109   b , as a result of which, for the above-mentioned reasons, the piston  123  is urged in the direction F. Guided by the guidances  140  the piston finally arrives with its end in shallow recess  120 , and because of the snugly fitting design the passage  115  is then closed off, in correspondence with the situation of FIGS.  2 B/ 3 B. 
   The situation shown in  FIG. 5B  is then achieved, and when the milk line is still attached to the teat of the cow via the teat cup, while maintaining the pressure in line  109   b , a mixture of air and cleansing medium can be discharged via line  109   a  in the direction E. This then arrives in pin  127  via the duct  127   a , through O-ring  152 , without leakage in duct  131 , in little duct  132  and finally said mixture comes out of discharge opening  129  in the direction C, forcefully to the teat and the teat cup. 
   Special now is that moisture falling back, in which iodine might be present, may fall on the portion of the piston  123  extending in the passage  115 , in the direction G, but that as a result of the short-circuiting made by the flattening  180 , said moisture can go past the lip  155  in the direction N, to the space  181  that is present between the narrowed portion  123   b  and the wall of the extension  118 . The distance between the widened portion  123   a , in particular the O-ring  153  and the piston end on the one hand and the distance between the drainage holes  114   a,b  with respect to said same end is such that a leakage path remains and the residual moisture can get to the outside via the drainage holes (arrow H). Here the moisture is able to flow around the narrowed portion  123   b  of the piston. Thus it is (further) counteracted that cleansing medium ends up at the other side, the milk collection side, when retracting the piston. 
   After the cleansing medium is discharged in this way the pressure in line  109   b  is maintained, and as is shown in  FIG. 5C , a pulsating mixture of water/air is discharged in the direction E. The teat cups however have been disconnected then, as a result of which they will hang down. The coupling piece  104  will therefore be inverted with respect to the  FIGS. 5A and 5B . The rinsing medium flows in the direction I, through the duct  127   a  in the pin  127 , through the ducts  131 ,  132  and flows out in the direction J, downwards through the discharge opening  129 . In the direction K the rinse water can continue its way to rinse the connected teat cup. 
   After that the pressure is lowered on the line  109   b , so that under the action of the spring  125 , on the one hand supporting against shoulder  185  at the widened inner end  123   a  of the piston  123  and on the other hand supporting against the ring  160 , again entirely to the inside, so that the passage  115  is entirely free again. Special now is that rinsing water can be supplied in the direction E through the duct  109   a , which rinsing water flows via the pin  127  then accommodated in the duct  131 , the pin  127  being short enough for the rinsing water to enter the little duct  132 , in order to come out in the direction L and then flowing around the narrowed piston portion  133   b  and the spring  125  to finally come out through the now lowermost drainage hole  141   a  in the direction M. The sealing ring  122  with lip  165  here ensures that no rinsing water with possible iodine residues ends up in passage  115 . 
   After that, the pressure is released from the line  109   a , and the situation shown in  FIG. 5A  is achieved, in which milking can take place again. During milking, the lip  155  ensures that as a result of the vacuum in the milk line, no possible residues can get from the chamber  119  in the passage  115 . 
   In the alternative embodiment shown in  FIGS. 6A-D  a coupling piece  204  is first shown in FIGS.  6 A,B having an input end  217  situated at the teat cup side and an end  216  leading to the milk collection chamber, in which coupling piece a milk passage  215  is formed. 
   The coupling piece  204  has a circular cross-section at the ends  216  and  217 , which however in the cross-section of FIGS.  6 B,D taper with walls  292 ,  293 , and in the cross-section in FIGS.  6 A,C flares of towards the middle of the coupling piece  204 . The walls  292  and  293  there merge in a truncated conical space, formed by cone walls  294 . A truncated conical closing body  223  is accommodated rotatable about its centre line and snugly fitting in said conical space. Said closing body  223  has an inner cavity  290  limited by wall  296  in which two holes  291   a ,  291   b  are formed that are situated diametrically opposite each other. As can clearly be seen in  FIG. 6C  a duct  227  extends through the closing body  223 , which duct is connected to a line  209  for compressed air/cleansing medium, and possibly water. The duct  227  is turned at right angles in order to debouch in passage  215  at the location of the discharge opening  229 , coinciding with the centre line of passage  215  and directed towards the end  217 . 
   The closing body  223  is attached in the coupling piece  204  with suitable means, such as for instance a threaded end/bolt, washer connection, against movement along its centre line. Other means, and sealing rings where needed, can be provided. This embodiment is meant to be schematically shown. 
   In the situation shown in the FIGS.  6 A,B, milk can flow in the direction A of the teat cup, through the passage  215 , through hole  291   a , space  290 , hole  291   b  and further to a milk collection point. 
   When milking is completed the closing body  223  is turned in the direction P over 90° by means of remote controllable means that are not further shown. Then the situation shown in the FIGS.  6 C,D is achieved, in which the discharge opening  229 , which in the situation of the FIGS.  6 A,B is either shielded or closed off by the cone wall  294 , has been released and lies in the centre line of the coupling piece  204 . Compressed air with cleansing medium is then supplied in the direction R through line  209 , and squirts in the direction S out of the discharge opening  229 .