Abstract:
A pump module and a device for producing a fluid jet with a pump module are disclosed. In an embodiment the pump module may include a pump housing in which at least one pump piston is mounted in a reciprocatingly movable manner and is provided with at least one sealing element which during a pumping operation interacts with a cylinder. For creating such a pump module producible in a simple manner and nevertheless exhibiting the functionality necessary for the pumping operation, embodiments disclose a valve block, which receives at least one valve associated with the cylinder, wherein the cylinder is sealed against the valve block. Furthermore, a cover element may abut against the valve block on a side opposite to the cylinder and between itself and the valve block forms an inlet passage leading to the cylinder and/or an outlet passage communicating with the cylinder.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to European Patent Application No. 16174463.6, filed Jun. 14, 2016, the contents of which are hereby incorporated by reference in its entirety. 
       TECHNICAL FIELD 
       [0002]    The present invention relates to a pump module and a device for producing a fluid jet. The pump module according to the invention is used as part of the device for producing the fluid jet. 
       BACKGROUND 
       [0003]    The present invention is intended to in particular specify a pump module which is applied for as a consumable part. The pump module according to the invention is intended to be particularly suitable for debridement by way of a water jet. In this treatment, a water jet is directed at a wound to clean the wound and, for example, remove scab. Wound healing has always been enhanced by debridement. 
         [0004]    A pump module with a pump casing in which at least one pump piston is mounted in a reciprocatingly movable manner which is provided with at least one sealing element that is sealingly received in the pump casing during the pumping operation, is known, for example, from US 2014/0079580 A1. Further pump modules for debridement by way of a fluid jet are known from prior art, for example, from US 2011/0150680 A1, US 2002/0176788 A1 or US 2010/0049228 A1. These prior art documents already show the efforts of the expert community to provide a pump module which is detachably connected to a drive in order to provide a device for producing a fluid jet in which the module is the consumable part. The pump module therefore has a relatively simple and inexpensive structure. 
       SUMMARY 
       [0005]    The present invention is also based on the problem of proposing a pump module of the type mentioned at the outset which can be produced in a simple manner but nevertheless has the functionality required for the pumping operation. 
         [0006]    In view of this, the present invention proposes a pump module with a valve block which receives at least one valve to the cylinder and is sealed against the cylinder. However, the valve is usually provided in the form of a valve liner in the valve block. Preferably, the valve block comprises the inlet and the outlet valve to each cylinder, preferably in the form of valve liners with associated valve bodies for the inlet and outlet valves. In addition, the valve block usually forms inlet passages leading to the inlet valve and outlet passages leading away from the outlet valve. These passages are preferably on the side of the valve block facing away from the cylinder provided as manifolds for several valves and/or on the surface of the valve block, commonly on a substantially planar surface which forms the valve block on the side opposite the cylinder. This side facing away from the cylinder is covered by a cover element which abuts against the valve element and forms the inlet passage or the outlet, respectively, between itself and the valve block. The inlet or outlet passage is commonly shaped as a recessed groove which is exposed toward the surface of the cover element and/or the valve block and which by the interaction of the valve block and cover element becomes a circumferentially closed passage which passes the fluid to be delivered with the pump toward the cylinder or discharges it from the cylinder. 
         [0007]    This embodiment makes it possible to produce the essential element of a pump with inlet and/or outlet valves in a simple manner. The valve block is there commonly provided with recesses which extend either at a right angle to the direction of motion of the reciprocatingly movable pump piston or parallel thereto. In view of a simple fabrication of the valve block, the latter is usually formed to be disk-shaped. The bores accommodating a valve and also the inlet and outlet passages are there commonly recessed extending parallel to the direction of motion of the pump piston. These recesses are there preferably produced by way of injection-molding so that the valve block exhibits the necessary seats for the valves and the flow passages without any finishing work. Preferably, a single passage can extend at a right angle thereto and form a connecting line for supplying fluid to the pump module. For this purpose, it can be necessary to provide the injection mold with a movable core. Beyond that, however, the injection mold can be designed in a very simply manner for forming the necessary flow guides into the valve block for the fluid toward the cylinder and away from the cylinder. 
         [0008]    Similarly, the cover element is preferably shaped as a disk. Here as well, grooves can be recessed on one or both main side surfaces of the disk and form the flow passages. The cover element is commonly also produced as an injection-molded member in the final contour, i.e. no further finishing work is required. All the recesses provided in the cover element, which can be designed in the form of a groove or a through bore, extend preferably parallel to the direction of motion of the pump piston. 
         [0009]    It arises with these explanations that the combination of the valve block and the cover element indicates a central element of the pump module which can be produced in a simple manner by injection-molding and forms the flow passages leading to the cylinder or cylinders and accommodates the valve or valves therein. The valves can there be designed in the form of valve liners which form a movable valve body and a valve opening which in the closed state of the valves cooperates with the valve body. The valve liners can be made of plastic material or metal and can be pressed into the valve block. The valve block itself there commonly forms a receiving space which in the direction of flow is upstream of the valve opening and accommodates the movable valve body so that the latter can move from its open to its closed position, preferably solely due to the pressure difference acting on the valve body. The valve body is there preferably formed by a freely movable valve ball which can commonly completely close the valve opening. 
         [0010]    The valve block can integrally form the cylinder or the cylinders. In one such embodiment, the integrally formed component is preferably produced by way of plastic injection molding and made from plastic material. The valve block preferably does not form the cylinder itself. Instead, this cylinder is commonly mounted as a separate component and sealingly connected to the valve block. Accordingly, a cylinder insert is proposed according to a preferred development of the present invention and forms the cylinder and abuts sealingly against the valve block. This cylinder insert can be formed from plastic material, in particular high-quality plastic material, or metal. The cylinder insert there has a surface quality to be expected from cylinders in the region of the inner circumferential surface which interacts in a sealing manner with the sealing element of the pump piston. The cylinder insert can be accommodated in a casing base and can be pressed against the valve block via this casing base, in particular pressed against it in a sealing manner. Alternatively, the cylinder insert can also be press-fitted to the valve block such that a tight connection is established between the valve insert and the valve block. It is equally conceivable to insert-mold the cylinder insert when producing the valve block in the injection-molding process in order to create an intimate connection between the valve insert and the valve block. The cylinder insert can also be glued or welded to the valve block. A fluid-tight connection between the valve block and the cylinder insert must there be ensured. 
         [0011]    For press-fitting the cylinder insert to the valve block, the latter commonly comprises a ring-shaped projection which extends over a certain length of the cylinder insert and surrounds it circumferentially and in a sealing manner. For the best possible press-fit of the cylinder insert, the latter commonly as an outer circumferential surface comprises a contouring or corrugation which together with an inner circumferential surface being formed by the valve block interacts in a sealing manner and holds the cylinder insert in a positive-fit manner. 
         [0012]    The cover element is there preferably connected directly to the valve block. This connection is preferably such that the cover element in a sealing manner seals the recesses provided in the phase boundary between the cover element and the valve block, thereby forming the inlet and outlet passages. The direct connection is there preferably formed by welding. Accordingly, the cover element is preferably formed from preferably transparent plastic material which is permeable to a laser, whereas the valve block is formed from plastic material which is impermeable to laser beams. The cover element can therefore from the side opposite the cylinder be welded to the valve block by way of laser beam welding. Laser beams are there guided through the cover material to the phase boundary and there converted to heat. With regard to uniform welding, it has proven to be advantageous to form the cover element substantially as a flat disk. The cover element accordingly comprises preferably two coplanar main side faces, of which one side surface in a sealing manner abuts directly against the valve block, and the other side is formed preferably in a flat manner to be adapted for introducing laser beams for welding. Other conceivable joining methods for producing the connection are ultrasonic welding, mirror welding, cold welding or gluing. 
         [0013]    In view of the simplest possible production and assembly of the pump module, a preassembled pump unit is according to a preferred development of the present invention proposed which comprises at least one cylinder insert, the valve block, and the cover element. The components of this pump unit are fixedly connected to each other so that the pump unit can be handled as a single component during the assembly of the pump module. This pump unit commonly also comprises the valve bodies for the inlet and outlet valves which are preferably disposed upstream of valve liners or received in such valve liners. The outlet for the fluid conveyed in the pump unit is commonly formed by a bore recessed in the cover element. The corresponding outlet is preferably recessed in the main side surface of the cover element disposed opposite from the cylinder. This outlet can be in communication with a stud-shaped outlet port which is directly connected to the cover element, for example, fastened thereto or formed integrally thereon. However, the outlet port is preferably provided on a head element which is arranged upstream of the cover element and there abuts tightly against the cover element, so that the outlet port provided on the head element is commonly in communication with the outlet of the cover element and is provided in axial extension thereto, i.e. in the continuation of the direction of motion of the pump piston. Accordingly, the preferably stud-shaped outlet port is preferably located on one face side of the pump module. The outlet port can be provided with a thread for fastening a Luer connection for connecting a pressure hose to the pump module. 
         [0014]    This head element is preferably by way of at least one tensioning element in abutment in a sealing manner commonly with the interposition of a sealing element, for example a sealing ring, where the tensioning element passes through the cover element and the valve block. The tensioning element also passes through a casing base possibly provided. If a head element is omitted, then the tensioning element is otherwise in abutment. The tensioning element is preferably a tensioning screw which commonly extends in the direction of motion of the pump piston. The thread-side end of the tensioning element is connected either to the head element, or to the cover element, or to a nut which is arranged upstream of the head element or the cover element, respectively. The tensioning screw can be in threaded engagement with the head element and/or the cover element. 
         [0015]    The above-mentioned casing base is preferably provided to form guide and locking surfaces for detachably fastening the pump module to a drive casing of a drive, the drive pusher of which is connectable to the pump piston for reciprocating operation of the pump piston. The preferably provided casing base thus assumes the function of adapting the pump unit to the drive. The casing base can also have the function of holding all functional elements of the actual pump unit and accommodating or surrounding them in an aesthetically pleasing form. The pump unit preferably comprises a front discharge region which can seat the valve block and/or the head element. This seat is preferably designed on a substantially cylindrically shaped casing base as a recess open on the face side. Furthermore, the casing base preferably comprises a rear drive region which seats the cylinder and/or the pump piston. The cylinder or the pump piston, respectively, can there completely or partially in the axial direction be covered by the casing base. 
         [0016]    The casing base can further comprise a guide sleeve associated with the pump piston. This guide sleeve is commonly located upstream of the actual cylinder and serves to guide the pump piston during the pumping operation. The guide sleeve is commonly not that region in which the piston with its sealing element is received in a sealing manner during the pumping operation and in which the fluid to be delivered is compressed. The respective guide sleeve instead preferably serves solely to guide the pump piston approximately in the middle length range thereof. 
         [0017]    The pump module can comprise one or more pump pistons with associated cylinders. At least two pump pistons with associated cylinders are preferably provided, which are each provided to be eccentric relative to a longitudinal axis of the elongate pump module, so that the pump module is fastened to the drive casing by axial displacement and rotation in the manner of a bayonet closure where a positive-fitting connector between the pump pistons and the drive pushers of the drive can at the same time be formed. In view of this, each pump piston preferably comprises a positive-fit element which is connectable to a positive-fit counter-element of the drive pusher to transmit a reciprocating cyclic axial motion of the drive pusher to the pump piston in a manner substantially free of play. 
         [0018]    According to a further preferred embodiment of the present invention, it is proposed that the inlet passage is in communication with at least two cylinders and the inlet passage is formed within the phase boundary between the cover element and the valve block such that the inlet passage at least partially circumferentially surrounds the outlet passage. The outlet passage is then located within the inlet passage, where passage sections leading to the inlet valve accommodate the outlet passage between themselves and an inlet port which is commonly provided at the upper side of the valve block. With proper alignment of the pump module, this configuration leads to the respective inlet being lower than the outlet, whereby the introduction of air bubbles into the rear side of the pump module is with certainty prevented. 
         [0019]    According to a further preferred embodiment of the present invention, a transponder element is attached to the casing. This transponder element carries information about the maximum service life of the pump module, i.e., information that is suitable to indicate the operating time over which the pump module can be employed. The transponder element can also forward information on the efficiency to a drive device into which the pump module according to the invention is inserted. The drive device there communicates indirectly or directly, for example, by way of a handpiece, which is marketed as consumable material together with a nozzle geometry adapted to the particular application, in order to transmit information to the drive device about the expected operating point of the nozzle cross-section. This embodiment makes it possible to adapt the operating point of the drive device to the efficiency of the pump module together with the handpiece and the nozzle cross-section provided therein. The transponder can there comprise a coil with which the signal from the handpiece is received, amplified and forwarded in the direction of the drive device. The transponder element also contains information for positioning the pump module relative to the drive casing. This ensures that the drive is due to the positional information of the pump module only started when proper fastening of the pump module to the drive casing has been established. The respective information of the transponder element is commonly read out by a reading unit which is provided on the drive casing. The reading unit can there preferably be provided in the circumferential direction of a substantially cylindrical pump module at a predetermined location and receive and thereby read out the positional information only when the pump module has been set to the correct position by way of a bayonet motion. The transponder element can also only inform the drive device that a pump module is provided as a consumable part in the region of the drive device, whereas the correct installation position of the pump module relative to the drive device can be indicated by a switch which is actuated only when the pump module has been fixed in the correct orientation on the drive casing. Both measures can there be coupled to one another in order to be able to operate the drive device, even in the event of a possibly bridged switch, only when a pump module with a transponder element is in fact provided in the vicinity of the drive device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    Further details and advantages shall arise from the following description of an embodiment in combination with the drawing, in which: 
           [0021]      FIG. 1  shows a first exploded view of the embodiment; 
           [0022]      FIG. 2  shows an exploded view according to  FIG. 1  for a pump unit of the embodiment shown in  FIG. 1 ; 
           [0023]      FIG. 3  shows a perspective side view according to the exploded view of  FIG. 1  of the assembled pump module onto the front discharge region; 
           [0024]      FIG. 4  shows a perspective side view according to  FIG. 3  into the open drive region; 
           [0025]      FIG. 5  shows a sectional view along the line V-V according to  FIG. 4  and  FIG. 11 , respectively, where the sectional plane includes the center longitudinal axis of the pump module; 
           [0026]      FIG. 6  shows a sectional view along the line V-V according to  FIG. 4 , where the sectional line includes the plane of motion of the pump piston; 
           [0027]      FIG. 7  shows enlarged detail VII according to  FIG. 6 ; 
           [0028]      FIG. 8  shows enlarged detail VIII according to  FIG. 6  for a pump piston penetrating deeper into the cylinder than in  FIG. 6 ; 
           [0029]      FIG. 9  shows a sectional view along line IX-IX according to  FIG. 4 , where the sectional plane includes the plane of motion and the center longitudinal axis of one of the pump pistons; 
           [0030]      FIG. 10  shows enlarged detail X according to  FIG. 9 ; 
           [0031]      FIG. 11  shows a perspective rear view similar to  FIG. 4 ; 
           [0032]      FIG. 12  shows enlarged detail XII according to  FIG. 11 ; 
           [0033]      FIG. 13  shows a perspective rear view of the pump unit according to  FIG. 2 ; 
           [0034]      FIG. 14  shows a sectional view along line XIV-XIV, according to the view in  FIG. 13 ; 
           [0035]      FIG. 15  shows detail XV according to  FIG. 14 ; 
           [0036]      FIG. 16  shows a rear top view onto the embodiment; 
           [0037]      FIG. 17  shows a sectional view taken along line XVII-XVII according to  FIG. 16 , where the sectional plane includes the center longitudinal axes of the two tensioning screws  6  and extends parallel to the plane of motion of the pump piston; 
           [0038]      FIG. 18  shows a perspective view of an embodiment of a device for producing a fluid jet; 
           [0039]      FIG. 19  shows the detail of  FIG. 18  in an enlarged view without the pump module; 
           [0040]      FIG. 20  shows the detail of  FIG. 18  in a top view; 
           [0041]      FIGS. 21 a - c    show a view similar to  FIG. 19  with a sequence of steps for joining the pump module and 
           [0042]      FIGS. 22 a - c    shows partially sectional top views of the interacting ends of the drive element and the drive counter-element and their relative position when pivoting during the joining process. 
       
    
    
     DETAILED DESCRIPTION 
       [0043]      FIG. 1  shows the essential components of the embodiment according to the present invention, which is a pump module. The pump module comprises a casing base  2  which accommodates two plunger bodies  4  within itself and surrounds them in a reciprocatingly movable manner. Furthermore, four tensioning screws  6  are shown which are embodiments of tensioning elements within the meaning of the present invention and in the assembled state engage with a head element  8  that is disposed before a pump unit  10  being received in casing base  2  while an annular RFID element  12  is interpositioned, which is an example of a transponder unit of the present invention. The casing base  2  for this purpose has a discharge region  14  which is configured as a cylindrical seat on the casing base  2 , where an axial slot  16  is formed adapted to receive an inlet port  18  of the pump unit  10 . The casing base  2  is likewise open at the end opposite to the discharge region  14  and forms a drive region  20 . 
         [0044]    As can be seen in  FIG. 1 , the casing base is formed to be substantially cylindrical. Formed on the outer circumferential surface on the casing base  2  are grooves  22  extending in the axial direction of the casing base  2  and transverse grooves  24  branching therefrom and extending transversely thereto which represent the guide and locking surfaces for attaching the pump module to a drive casing, the details of which are illustrated in  FIG. 18  et seqq. and the associated description. 
         [0045]    The pump unit  10  is formed by a valve block  26  and a cover element  28  abutting thereagainst, where two cylinder inserts  30  project from the valve block  26  on the side disposed opposite to the cover element  28 , of which only one cylinder insert  30  can be seen in  FIG. 1  and which during the pumping operation interact with the plunger bodies  4 . For this purpose, the plunger bodies  4  each carry a sealing element  32  in the form of a sealing ring which is in the region of the front free end of the plunger body  4  held thereon in a positive-fit manner. 
         [0046]      FIG. 2  shows that the two cylinder inserts  30  on their end facing the valve block  26  comprise a wavelike contour on their outer circumference which are formed into the valve block  26  for the sealing insertion of the cylinder inserts  30 . A respective valve liner  34  is provided between the cylinder inserts  30  and the valve block  26  and together with a valve ball  36  each forms an outlet valve  37 . Valve liners  38  with associated valve balls  40  are illustrated on the side opposite to the cylinder inserts  30  and form inlet valves  41  to the respective cylinder inserts  30 . The inlet valves  41  are received in inlet valve bores  42  which are recessed in the valve block  26  and communicate with an inlet passage  44  which is recessed in a projection  46  as a U-shaped groove being open on one side and which is covered by the cover element  28 . The outlet valves  37  are seated in corresponding outlet valve bores, one of which is shown by way of example in  FIG. 9  and is provided with reference numeral  50 . As illustrated in  FIG. 2 , inlet port  18  is integrally formed on the valve block  26 . From the side facing the cover element  28 , two fitting elements  52  of different diameters protrude from and project beyond the sealing surface  54  formed by the projection  46 . The cover element  28  has bores  56  formed adapted for these fitting elements  52  which serve to correctly position the cover element  28  relative to the valve block  26 . The fitting elements  52  and the fitting bores  56  there have mutually adapted diameters so that the cover element  28  is according to a poka-yoke function always arranged in the correct orientation and position when assembling the cylinder insert  30  on the valve block  26 . 
         [0047]    In addition to these two fitting bores  56 , the cover element  28  also comprises an outlet bore  58 . 
         [0048]    The valve block  26  comprises four through bores  60  corresponding to the tensioning screws  6  and which, firstly, pass through the sealing surface  54  formed by the projection  46  and, secondly, annular surfaces  62  which are configured to be adapted for the abutment against the cover element  28  and are provided at the same height. The cover element  28  abuts sealingly against the surfaces  62  and  54  and is welded thereon by laser beam welding. For this purpose, the cover element  28  is formed from laser-transparent material, whereas the valve block  46  is formed from plastic material absorbing laser beams. Both parts can accordingly be connected by way of laser transmission welding, where the cover element  28  made of plastic material is at the phase boundary to the valve block connected in a positive substance-fit manner to the plastic material of the valve block  26 . The inlet passages  44  and an the outlet passages, designated by reference numeral  64  and comprising a U-shaped channel recessed on the valve block  26  and covering the cover element  28 , are formed thereby. The outlet passage  64  is via the outlet bore  58  in communication with an outlet port bushing  66  being integrally formed on the head element  8  and being provided in axial extension of the outlet bore  58  and provided with an external thread on its outer circumference for forming a Luer connection. A pressure hose can accordingly by way of a Luer connection be connected in a simple way to the outlet port bushing  66 . 
         [0049]      FIG. 4  shows a perspective side view with a top view upon the face side end of the casing base  2  and of the drive region  20 . The plunger bodies  4  are surrounded by the casing base  2  and with their one end project into the drive region  20 . As is in particular evidenced by  FIG. 5 , the end of the plunger body  4  on the drive side, which forms a positive-fit element shaped as a hammer head  68 , projects beyond the casing base  2  at the end side. Otherwise, however, the plunger body  4  is axially covered by the casing base (see  FIG. 5 ). 
         [0050]    As can be seen from a synopsis of  FIGS. 4, 5, 6 and 11 , the casing base  2  is configured as an injection-molded member with relatively uniform wall thicknesses, so that good solidification behavior is obtained during the injection-molding process of the casing base  2 . Plastic materials for the production of the components of the module can be PA, PE, PP and/or POM, possibly as filled plastics, for example, filled with minerals and/or fibers. For this purpose, the casing base  2  has a center recess  70  which is via radial webs  72  connected to the outer circumferential surface of the casing base  2 , where the radial webs  72  branch off from a polygon structure  74  which connects guide sleeves  76  between the radial webs  72  inwardly to the respective plunger bodies  4  which are supported via further radial webs  78  on the outer circumferential surface of the casing base  2  (cf.  FIG. 16 ). 
         [0051]    The casing base  2  forms a radially extending partition wall  80  which is inter alia provided with passage bores  82  for the tensioning screws  6  (cf.  FIG. 17 ). The tensioning screws  6  there completely penetrate the partition wall  80 , the valve block  26  and the cover element  28 , and partially the head element  8  and are in threaded engagement with the latter. For this purpose, the tensioning screws  6  are self-tapping. The head element  8  can also by welding be welded to the recess formed by the casing base  2  in the discharge region  14  and thereby be indirectly connected to the valve block  26  and the cover element  28 . A sealing ring  83  seals the passage formed by the outlet port bushing  66  against the outlet bore  58  of the cover element  28  (cf.  FIGS. 1 and 5 ). 
         [0052]    In the axial extension of the guide sleeves  76 , the casing base  2  forms cylinder insert receiving bores  84  reaching up to the partition wall  80  which are formed adapted to receive the cylinder inserts  30  and which are radially thickened approximately at the height of the partition wall  80  in order to form between the cylinder insert  30  and the material of the casing base  2  an annular space into which a protruding ring collar  86  of the valve block  26  fits. This ring collar  86  is shown, for example, in  FIGS. 6 and 9 . The ring collar  86  serves to establish the sealing connection between the cylinder insert  30  and the valve block  26 . As illustrated in  FIG. 8 , a contoured outer circumferential surface of the cylinder inserts  30  is there accommodated within the ring collar  86  and is also positively locked therewith Each cylinder insert  30  is by pressing inserted into the ring collar  86  and is thereby sealingly connected to the valve block  26 . 
         [0053]    The partition wall  80  further forms an annular groove which opens toward the valve block  26  and is formed adapted to receive the RFID ring  12  so that this RFID ring  12  can be arranged between the partition wall  80  and the valve block  26  (cf.  FIG. 5 )  FIG. 5  there in the lower part of this annular groove shows a thickening of the RFID ring  12  which represents the data carrier. The remainder of the region of the RFID ring  12  being slimmer in the radial direction serves for adequate positioning within the casing base  2  (cf.  FIG. 1 ) and also as a coil for signal amplification of a signal output, for example, from a handpiece, with which the type of nozzle geometry installed in the handpiece is indicated. 
         [0054]    As illustrated in  FIGS. 5 and 13 , the valve block  26  is also configured as a component having the same wall thicknesses and can therefore be produced well by way of plastic injection molding. in particular  FIG. 5  illustrates several of support ribs  88  extending in the direction of motion of the plunger bodies  4  and being supported on the partition wall  80  and connecting sleeve segments  90  which form passage bores  92  for the tensioning screws  6  that are flush with the passage bores  82  through the partition wall  80 , where the above-mentioned sleeve segments  90  form the previously mentioned annular surfaces  62  for abutment of the cover element  28 . 
         [0055]      FIGS. 14 and 15  illustrate the arrangements of the inlet and outlet valves  37 ,  41  in the valve block  26 . This valve block  26  has bores  42 ,  50  being adapted to receive the corresponding valve lines  34  and  38 , and each of which having a receiving space  94  downstream in the flow direction of the fluid in which the valve ball  36  or  40  are respectively located. In the closed state of the valve, this valve ball  36  or  40 , respectively, interacts with a valve opening which is formed by the flow-free end of the corresponding valve liner  34 ,  38 . This position is in  FIG. 15  shown for the valve ball  36  of the outlet valve  37 , whereas the valve ball  40  of the inlet valve  41  unblocks the corresponding valve opening.  FIG. 15  shows a state in which the plunger body  4  increases the displacement within the cylinder insert  30  and the fluid to be pumped is introduced into the displacement chamber through the inlet passage  44 , whereas the outlet passage is closed by the outlet valve  37 . The respective valve balls  36 ,  40  are in the embodiment shown provided freely movably in the receiving space  94  and are captively held in the valve block  26  due to the diameter ratios between the valve opening and the diameter on the flow-remote side of the passage which branches from the valve opening and is formed in the valve block  26 . For assembly, the respective ball  36 ,  40  is first inserted into the receiving space  94 . The valve liner  34  or  38 , respectively, is then pressed into the valve block  26 . The valves  37 ,  41  are then preassembled in the valve block  26  in a captive manner. 
         [0056]    As can further be seen in  FIG. 15 , the cylinder insert  30  pressed into the valve block  26  on the face side abuts against the valve liner  34  of the outlet valve  37 , whereby the valve  37  provided on the pressure side of the pump is additionally secured in position and prevented from being undesirably pressed out from the force fit to the valve liner  36 . 
         [0057]    In particular  FIG. 7  illustrates a first tapered feed-in device  96  which is formed by the casing base  2  and which is provided before the cylinder insert  30  in the direction of the drive region  20 . This first tapered feed-in device  96  facilitates the insertion of the plunger body  4  with its front end, on which the sealing element  32  is located, into the cylinder formed by the cylinder insert  30 . When the plunger body  4  is inserted, the sealing element  32  is arranged concentrically with respect to the cylinder insert  30  and brought approximately to the latter&#39;s inner diameter. A second tapered feed-in device  98  is formed by the cylinder insert  30  itself. Located within this second tapered feed-in device  98  is the sealing element  32  in the parking position illustrated in  FIGS. 6 and 7 . The sealing element  32  is provided with a radial distance to the cylinder insert  30 . The radial gap resulting therefrom allows the passage of fluid and/or gas for sterilization or disinfection of the embodiment after assembly of all the components. This parking position is defined by a locking element which presently is formed by an engaging pawl  100  integrally formed onto the casing base  2 . This engaging pawl  100  can be seen in particular in  FIGS. 10 to 12 . The engaging pawl  100  is formed by cutting free the end of the guide sleeve  76  on the drive side. The engaging pawl  100  has a locking projection  102  which is illustrated in  FIGS. 9 and 10  and in the parking position engages in a locking groove  104  being formed between two ring-shaped projections  106 ,  108  which are integrally formed on the plunger body  4  as a single part (cf.  FIG. 10 ). The front ring-shaped projection  108  forms an almost strictly radially extending flank of the locking groove  104 , whereas the rear ring-shaped projection  106  comprises an inclined flank which facilitates the advancement of the plunger body  4  from the parking position to a pumping or operating position. In a pumping or operating position, the sealing element  32  is in sealing abutment against the inner circumferential surface of the cylinder, presently the cylinder element  30 . It can be assumed that  FIGS. 9 and 10  represent the uppermost pumping position and  FIG. 8  the lowest pumping position. The stroke of the plunger body  4  takes place between these two positions according to  FIGS. 8 and 9 . 
         [0058]    The previously described parking position is locked by the configuration of the engaging pawl  100  and the locking groove  104 . Axial pressure against the plunger body  4  from the drive side beyond a critical magnitude of the pressure force leads to the parking position being released and the plunger body  4  being displaced deeper into the casing and to the pumping position. In this pumping position, the projections  106 ,  108  guide the plunger body  4  also relative to the guide sleeve  76  which is formed by the casing base  2  (cf.  FIGS. 9, 10 ), as a result of which higher running smoothness of the plunger body  4  during the pumping operation is obtained. The plunger body  4  is in particular prevented from buckling when axially loaded, so that the plunger body  4  can be produced from a relatively soft material, such as, for example, plastic material. 
         [0059]    As illustrated in  FIG. 6 , the plunger body  4  in the parking position projects with its hammer head  68  over the casing base  2 , whereby an optical indicator for verifying the parking position is provided. After joining to the drive, when the plunger bodies  4  are necessarily transferred from the parking position to a pumping position, the ends on the drive side with the hammer head  68  are each exposed within the casing base  2  and the axially open rear recess formed there in the drive region  20 . 
         [0060]    As the description of the embodiment illustrates, the inlet and outlet passages  44 ,  64  are in the pump module according to the invention formed between the cylinder insert  30  and the sealing element  32 . They extend within a phase boundary between the valve block  26  and the cover element  28 . The inlet passage  44  provided there distributes fluid introduced from an upper end near the inlet port  18  to the respective inlet valves  41 . The fluid is guided in the phase boundary up to the inlet valves  41  at the outer edge of the phase boundary and accordingly at least partially surrounds the outlet passage  64 . This outlet passage  64  communicates with several outlet valves  37 , two in the present case. Within the phase boundary between the cover element  28  and the valve block  26 , the outlet passage  64  directs the pressurized fluid up to a collection point which is flush with the discharge passage formed by the outlet port bushing  66 . The collection point is there also located within the phase boundary between the cover element  28  and the valve block  26 . The largest part of the inlet passage  44  and/or the outlet passage  64  is in particular formed within the phase boundary between the valve block  26  and the cover element  28 . The largest part there represents at least 50%, preferably 60%, of the total length of the flow path of the respective passage within the pump module. This flow path for the inlet side begins with the inlet opening of the inlet port  18  and ends at the inlet valve  41 . The respective path on the outlet side begins with the opening formed by the outlet port bushing  66  and ends at the outlet valve  37 , presently the receiving space  94  of the corresponding valve  37 . 
         [0061]    Another important aspect of the invention is the pump unit  10  which consists of the valve block  26  and the cover element  28  with the valves  37 ,  41  and the cylinder inserts  30  installed therein. This pump unit  10  is preassembled. The invention can there also be varied in that the cylinder is formed by the casing base  2  itself or a cylinder element which is received in the casing base  2  and which is sealingly abutted against the valve block  26 . It is there conceivable that the collar, which is apparent from  FIG. 7 , following the first tapered feed-in device  96  abuts directly against a cylinder insert and—subject to pre-loading the casing base  2 —presses the latter against the valve block  26 , and in particular together with an O-ring which can be arranged at the phase boundary between the casing base  2  and the valve block  26  and thereby seals the cylinder insert thus provided. 
         [0062]    Furthermore, it is significant that a parking position is defined in which the pump piston formed by the plunger body  4  is fixated such that the plunger body  4  is with a certain axial pressure displaced from the parking position to a pumping position. The sealing element  32  is in the parking position certainly not in abutment against the inner circumferential surface of the associated pump cylinder. The sealing element  32  is regularly provided with a radial distance from adjacent casing parts of the pump module so that the sterilization or disinfection can occur past the cylinder and the piston. All the flow-conducting parts of the pump module are there completely coated with the disinfecting or sterilizing agent and thereby effectively sterilized. 
         [0063]      FIG. 19  shows a perspective side view of an embodiment of a drive unit  110  with a drive—being an electric drive—provided in a drive casing  112 . A holder  114  protrudes from the drive casing  112  for holding a fluid bag. Exposed on the drive casing  112  are also various control elements  116  which serve to actuate the drive and to switch the drive on and off. Reference numeral  118  denotes a substantially cylindrical recess into which a pump module according to  FIGS. 1 to 17  being denoted with reference numeral  120  is inserted and which is in comparison with these figures shown in simplified form. The casing base  2  comprises lugs  122  that protrude inwardly into the recess  118  and are embodiments of positive-locking elements of the present invention. Four lugs  122  are presently provided distributed on the circumference. The lug identified by reference numeral  122 . 4  has a smaller radial extension and a smaller extension in the circumferential direction than the other lugs  122 . 1  to  122 . 3  in order to allow for unique association of the pump module  120 . Other types of a poka-yoke configuration are conceivable. Grooves with different angular offset relative to one another can be provided on the outer circumferential surface of the casing, in particular the casing base  2 , so that the pump module  120  can be inserted into the recess  118  only in a predetermined manner. Exposed in the recess  118  are furthermore drive elements in the form of drive pushers  124  which are connected to the drive provided within drive casing  112  and which are drivable in reciprocating manner in the longitudinal direction. The drive pushers  124  form an abutment surface  126 . Two drive pushers  124  are presently provided. A claw  128  being C-shaped in a top view projects over the abutment surface  126  and forms a hammer head seat  130  between itself and the abutment surface  126 . 
         [0064]    As is evident in particular from  FIGS. 11 and 16 , of the four grooves  22  on the outer circumference of the casing base  2  extending strictly in the axial direction along the center longitudinal axis L, the groove designated with reference numeral  22 . 4  is formed adapted for the exact reception of the smaller lug  122 . 4 . Due to the interaction of in particular the smaller lug  122 . 4  with the smaller groove  22 . 4 , biunique orientation of the pump casing  120  is defined when joining, i.e. when inserting the pump module  120  into the recess  116 . The pump module  120  can be inserted only at an angle perpendicular to a final position offset by 30° shown in  FIG. 21 c   . This pivoted position is illustrated in  FIG. 21 b   . The hammer head  68  projects beyond an end-side pump piston section  132  of each pump piston  4  that has a smaller diameter than the remaining pump piston  4 . The hammer head  68  defines the face-side, connection-side end of the pump piston  4  and there forms a counter-surface  134  to the abutment surface  126 . 
         [0065]    The groove  22  together with the transverse groove  24  forms a guide for a bayonet lock with the respective lug  122  to first perform an axial insertion motion which then comes to an end when the lugs  122  abut against the inside lower end of the grooves  22 , to thereafter be pivoted in a pivotal motion into the transverse groove  24  and thereby be axially locked. In the final position on the end side abutting against the transverse groove  24 , a catch projection can be active which forms an anti-rotation lock between the pump module  112  and the drive casing  2  so that the pump module  112  is locked in its final position. 
         [0066]    Drawn in  FIG. 22 a    within the transverse groove  24  is further a catch and switch projection  136  formed on a spring arm and exposed in the transverse groove  24  and formed fixedly on the pump base  2  (cf.  FIG. 3 ). This catch and switch projection  37  is associated with a switch  138  provided centrically in the lug  122 . 2 . The switch  138  is preloaded in the radial direction inwardly relative to the recess  118  and interacts accordingly with the catch and switch projection  136 . Only the actuation of this switch  138  by the catch and switch projection  136  gives rise to the possibility of driving the drive pusher  124 . If the pump module  10  is accordingly not connected in the prescribed manner to the drive unit  1 , then the drive unit can not be operated. The drive casing  112  is additionally provided with a reading unit which recognizes the correct orientation of the RFID ring  12  and thereby of the pump module  120  relative to the drive casing  112  and only then releases the output. This prevents operation of the device with the switch  138  being bridged. 
         [0067]      FIGS. 21 a  to  c    illustrate the insertion of the pump module  120  into the recess  118 . As already mentioned above, pump module  120  is first pivoted by 30° in the counterclockwise direction relative to the final position to make the lugs  122  coincide with the grooves  22  (cf.  FIG. 21 a   ). The pivoted position is characterized by an alignment arrow  140  which can be clearly seen in  FIG. 3  and is in  FIG. 21 a    aligned with a position indicator  144  provided on the casing side. In this relative orientation, the pump module  120  can now be inserted into the recess  118 . This axial insertion motion is guided by the lugs  122  which engage in the grooves  22  that are formed to correspond thereto. In the illustration according to  FIG. 21 b   , this axial insertion, in  FIG. 21 b    being illustrated by a straight-line arrow, is terminated. The pump module  120  is now inserted fully into the recess  118 . Thereafter, the pump module  120  is pivoted by 30° in the clockwise direction, as indicated by the arrow in  FIG. 21 c   . Following this pivotal motion by 30°, the pump module  120  has reached its final position. The final position is indicated to the user by a directional arrow  142  which is provided on the outer periphery of the casing base  2  and which is in the final position aligned with a position indicator  144  provided on the drive casing  2 . The directional arrow  142  also indicates the direction of insertion for the pump module  2  into the recess  8 . 
         [0068]    When joining the pump module  120  and the drive casing  112 , the drive pushers  124  and the pump pistons  4  are approximate to each other. Due to the axial guidance of the lugs  122  in the grooves  22 , the counter-surface  134  formed by the hammer head  68  is at least in part located above the abutment surface  126  formed by the drive pusher  124  (cf.  FIG. 22 a   ). A progressive axial motion finally leads to the pump piston  4  being in abutment at the end side against the abutment surface  126 . As the pump module  120  continues to approach the drive casing  112 , the parking position is released and the pump piston  4  is forced deeper into the casing base  2  and to a pumping position. No further relative axial motion between the drive pusher  124  and the associated pump piston  4  is thereafter given. 
         [0069]    The respective hammer head  68  of the two pump pistons  4  is there located in an eccentric position relative to the center of the drive pusher  124 , which is shown in  FIG. 22 a   . The casing base  2  is after the axial abutment of both pump pistons  30  against the drive pushers  124  typically displaced by a further minor distance axially relative to the drive casing  2 , so that it is ensured that axial abutment of the pump piston  4  is always reliably obtained against the drive pusher  124  until the axial final position has been reached when joining the pump module  120  and drive casing  112 , before casing base  2  is pivoted relative to the drive casing  112 . The configuration is certainly to be such that reliable abutment of the pump piston  4  against the drive pusher  124  is after completion of the axial insertion motion obtained in any conceivable position of drive pusher  124 , even in a position where the drive pusher  124  is in the lowest position within the recess  8 . 
         [0070]    After this axial final position has been reached, the pump module  120  is then pivoted in the clockwise direction. The hammer heads  68  being disposed eccentric to the center of this pivotal motion are thereby—as illustrated in  FIGS. 22 a  to 22 c   —with their counter-surface  134  in a sliding manner displaced on the abutment surface  126  relative to drive pusher  124 , namely in a plane extending perpendicular to the direction of insertion. The previously eccentric arrangement of the pump pistons  4  relative to drive pushers  124  according to  FIG. 22 a    therafter, via an intermediate position shown in  FIG. 22 b   , approaches the final position shown in  FIG. 22 c   . In this final position, the lugs  122  abut against stops which are formed by the transverse grooves  24 . The casing base  2  is commonly locked against the drive casing  2 . The pump pistons  4  are arranged substantially concentric to the drive pushers  124 . Each claw  128  engages over the associated hammer head  68 . The hammer head  68  is by engagement of the hammer head seat  130  comprising the claw  128  held in an axially positive-locking manner. The hammer head seat  130  is typically in the axial direction matched exactly to the height of the hammer head  68  so that a play-free axial positive-locking connection between drive pusher  124  and the pump piston  4  arises. 
       LIST OF REFERENCE NUMERALS 
       [0000]    
       
           2  casing base 
           4  plunger body/pump piston 
           6  tensioning screw: 
           8  head element 
           10  pump unit 
           12  RFID ring 
           14  discharge region 
           16  axial slot 
           18  inlet port 
           20  drive region 
           22  groove 
           24  transverse groove 
           26  valve block 
           28  cover element 
           30  cylinder insert 
           32  sealing element 
           34  valve liner 
           36  valve ball 
           37  outlet valve 
           38  valve liner 
           40  valve ball 
           41  inlet valve 
           42  inlet valve bore 
           44  inlet passage 
           46  projection 
           50  outlet valve bore 
           52  fitting element 
           54  sealing surface 
           56  fitting bore 
           58  outlet bore 
           60  through bores 
           62  annular surface 
           64  outlet passage 
           66  outlet port bushing 
           68  hammer head 
           70  center recess 
           72  radial web 
           74  polygon structure 
           76  guide sleeve 
           78  further radial web 
           80  partition wall 
           82  passage bore 
           83  sealing ring 
           84  cylinder insert receiving bore 
           86  ring collar 
           88  support rib 
           90  sleeve segment 
           92  passage bore 
           94  receiving space 
           96  first tapered feed-in device 
           98  second tapered feed-in device 
           100  engaging pawl 
           102  locking projection 
           104  locking groove 
           106  ring-shaped projection 
           108  ring-shaped projection 
           110  drive unit 
           112  drive casing 
           114  holder 
           116  control element 
           118  recess 
           120  pump module 
           122  lugs 
           124  drive pusher 
           126  abutment surface 
           128  claw 
           130  hammer head seat 
           132  pump piston section 
           134  counter-surface 
           135  spring arm 
           136  catch and switch projection 
           138  switch 
           140  alignment arrow 
           142  directional arrow 
           144  position indicator 
         L center longitudinal axis