CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims priority as the National Stage Entry of PCT Patent Application No. EP2013/064520, filed on Jul. 10, 2013. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates, generally, to catheters and, more specifically, to a bladder catheter. 
     2. Description of the Related Art 
     The invention relates to a urinary catheter with a tube, wherein the tube has an insertion section for insertion in a bladder via a urethra, and wherein the tube has a connecting section for the connection of connection elements thereto, wherein liquid from the urethra can be discharged at the connecting section via the insertion section, wherein a closeable valve is disposed between the insertion section and the connecting section, such that a discharge of liquid from the connecting section when the valve is closed can be prevented. 
     A number of urinary catheters of this type are known from the prior art, and can no longer be dispensed with in the medical field. Urinary catheters of this type are used, for example in hospitals, with patients who can no longer leave their bed due to an operation or due to their age. These types of urinary catheters are also used with other disruptions pertaining to the voiding of the bladder. Different forms of these transurethral urinary catheters, meaning urinary catheters that are inserted into the bladder via the urethra, are known. Thus, there are, for example, intermittent catheters, which are removed from the urethra after a single voiding of the bladder. With indwelling catheters, which are normally designed as at least a two-way catheter, a balloon is disposed on the tip of the urinary catheter, wherein the urinary catheter exhibits one channel for urine discharge, and one channel for filling the balloon when the urinary catheter is inserted. The urinary catheter is then anchored long-term in the urethra. 
     Moreover, three-way catheters, the so-called flushing catheter, are also known from the prior art. In contrast to a two-way catheter, these urinary catheters exhibit an additional channel, through which flushing solutions can be introduced into the bladder. These three-way catheters are used, for example, if there is heavy bleeding in the bladder, in order to prevent blood clotting in the bladder by flushing the bladder. Other urinary catheters are known, for example, from DE 20 2008 017 850 U1, U.S. Pat. No. 5,429,620 A, U.S. Pat. No. 5,476,534 A, US 2006/095019A1, US 2006/212024 A1, U.S. Pat. No. 6,902,146 B1, WO2008/144622 and US 2005/148999 A1. 
     These urinary catheters known from the prior art exhibit certain disadvantages however. The known urinary catheters must be equipped with a urine bag for collecting the urine discharged from the connecting section. When a urine bag of this type is replaced, meaning when the urine bag is full, the connecting section must be held in place above the height of the urethra, because otherwise, urine can leak from the connecting section. Particularly in a hospital environment, this represents an unacceptable risk to the patient and the hospital staff. Furthermore, when the urine bag is connected, urine can be discharged into the urine bag at the connecting section through the insertion section at any time. Patients wearing a urinary catheter over a longer period of time thus lose their natural bladder reflex. After removing the urinary catheter, this can lead to problems pertaining to a natural “passing water” by the patient. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes the disadvantages in the related art in providing a urinary catheter with which the comfort of a patient can be increased. 
     In this way, a urinary catheter having a valve, designed as a slide valve, has three switching settings, wherein the valve is closed in a closed setting and wherein the valve is air-permeable in a middle setting and wherein the valve is open in a releasing setting. This is advantageous because, then when the valve is closed, a full urine bag can be replaced, without urine being able to escape from the connecting section of the urinary catheter. It is thus not only more hygienic, but a urinary catheter of this type is also advantageous from an ecological perspective, because costs pertaining to hygienic measures in hospitals, for example, which until now have been necessary, can be eliminated by a urinary catheter of this type. With a slide valve, a particularly secure sealing can be enabled, while at the same time a very simple operation thereof is enabled. A patient or medical staff can then easily and securely discharge urine from a bladder, or further prevent the discharge of urine by closing the slide valve. The provision of three switching settings is particularly advantageous because the removal of air from the bladder of a patient is enabled in the middle setting, wherein a discharge of urine can be prevented. 
     The use of urine bags can also be avoided with a urinary catheter of this type. It can then be ensured, with a urinary catheter of this type, that a patient does not lose his bladder reflex. Instead, this remains intact. The use of a urine bag is no longer necessary because a patient can visit a toilet when he detects the feeling of a full bladder, wherein the patient can then void his bladder in a toilet by opening the closable valve. Particularly from an ergonomic perspective, a urinary catheter of this type can increase the comfort level of a patient to an enormous extent. A patient need not walk around with a urine bag. Instead, he is able to use conventional, public, for example, toilets. The urinary catheter can be hidden in the underwear after the bladder has been voided, without wetting the clothing. 
     In the night, a urine bag can then be connected to the connecting section of the urinary catheter, for collecting urine. 
     Advantageously, a urinary catheter of this type, or the tube, respectively, can be manufactured from rubber and/or latex and/or polyvinyl chloride (PVC) and/or silicone. Advantageously, the outer surface of the tube exhibits a hydrophilic coating, for increasing the sliding capacity into the urethra. 
     Furthermore, it is advantageous if an air-permeable filter and/or membrane section is provided in the valve. A filter and/or membrane section of this type can be disposed thereby, such that it enables air to escape when the valve is moved to the middle setting, wherein a discharge of urine can be prevented. It is advantageous that the filter and/or membrane section be manufactured from a hydrophobic acrylate polymer. 
     Further advantageously, the urinary catheter has a closed hollow tip with at least two opposing openings, in accordance with the Nelaton catheter design, at its end facing away from the connecting section. It is, however, also conceivable, that the urinary catheter is a Foley catheter. A Foley catheter exhibits a Nelaton tip, and has an additional balloon on its tip for securing the urinary catheter in the bladder. The design for this urinary catheter, as a Nelaton catheter, is advantageous, because the Nelaton catheter can be inserted particularly easily in a urethra of a patient. 
     It is also advantageous if the urinary catheter is a transurethral catheter. A transurethral urinary catheter can, in contrast to a suprapubic urinary catheter, be inserted in the bladder through the urethra of a patient. 
     Another advantageous design of the urinary catheter provides that the urinary catheter is an indwelling catheter. In this case, the urinary catheter can, in particular, be a two-way catheter, wherein urine can be discharged from the urethra through a central channel, while, on the other hand, a balloon, which can be provided on a tip of the urinary catheter, can be filled with water through a second channel. An indwelling catheter of this type can be disposed self-retaining in a urethra. 
     Another advantageous design of the urinary catheter provides that the urinary catheter is a flushing catheter. A flushing catheter of this type can, in particular, be a three-way catheter, with which, in contrast to a two-way catheter, a flushing solution can be introduced into a bladder through an additional third channel. In order to prevent blood clotting in the bladder, a bladder can be flushed with flushing liquids using a flushing catheter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objects, features, and advantages of the present invention will be readily appreciated as the same becomes better understood after reading the subsequent description taken in connection with the accompanying drawing wherein: 
         FIG. 1  shows a urinary catheter. 
         FIG. 2  shows an enlarged depiction of the tip of the urinary catheter. 
         FIG. 3  shows a depiction of the connecting section of the urinary catheter. 
         FIG. 4A  shows a first embodiment of a slide valve for the urinary catheter in the closed setting. 
         FIG. 4B  shows the first embodiment of the slide valve in the releasing setting. 
         FIG. 5A  shows a second embodiment of a slide valve for the urinary catheter in the closed setting. 
         FIG. 5B  shows the second embodiment of the slide valve in the middle setting. 
         FIG. 5C  shows the second embodiment of the slide valve in the releasing setting. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference now to the drawing(s),  FIG. 1  shows a urinary catheter  10  with a tube  12 . This tube  12  has an insertion section  14  with a tip  16 , illustrated in greater detail in  FIG. 2 . This insertion section  12  can be at least partially inserted in a bladder of a patient through a urethra. The tube  12  has a connecting section  18  on its end facing away from the insertion section  14  or the tip  16 , respectively. Connection elements can be inserted into this connecting section  18 , or more specifically, into the opening  20  of the connecting section  18 . The urinary catheter  10  has a valve  22  designed as a slide valve on its end facing the connecting section  18 . This valve  22  is disposed between the insertion section  14  and the connecting section  18 , such that a discharge of urine from the opening  20 , or the connecting section  18 , respectively, can be prevented when the valve  22  is in a closed setting. 
     The urinary catheter  10  can be a so-called two-way catheter. The urinary catheter  10  thus has a connecting section  24  at its end facing the connecting section  18 . A balloon can be disposed at the tip  16 , and can be inflated with a liquid through this connecting section  24 . Using this balloon, the urinary catheter  10  can be fixed in the bladder after it has been inserted in a bladder through a urethra. The urinary catheter  10  is thus retained in its position by the balloon. In order to fill the balloon, a secondary channel  30  is provided in the tube  12 , separated from a main channel  28 . If liquid can then enter the balloon at the connecting section  24  through the secondary channel  30 , the balloon inflates and holds the urinary catheter  10  in position. The main channel  28 , in turn, serves as a connection for the tip  16  of the urinary catheter  10  to the connecting section  18 . 
     Urine can be discharged at the tip  16  depicted in  FIG. 2 , when a urinary catheter  10  is inserted in a bladder, through two opposing eye-like openings  32 , through the main channel  28  running in the insertion section  14 , into a connection element connected at the connecting section  18 , or directly into a toilet, respectively. 
     The tip  16  depicted in  FIG. 2  represents a tip  16  of a urinary catheter configured as a so-called Nelaton catheter design. For an easier insertion of the urinary catheter  10 , or the insertion section  14 , respectively, in a urethra of a patient, the tip  16  thus has a spherical cone  34 . This spherical cone  34  serves to facilitate an easy insertion of the urinary catheter  10 , wherein this can be designed such that it is as comfortable for the patient as possible. 
       FIG. 3  shows a detail view of the connecting section  18  of the urinary catheter  10 . Connection elements such as a urine bag, for example, can be connected to the connecting section  18  through the opening  20 . The alternate connecting section  24  is clearly visible in  FIG. 3  and is connected to the secondary channel  30  for filling the balloon. Furthermore, the valve  22 , which is designed as a slide valve, is depicted in  FIG. 3  in the closed setting. The functioning of the valve  22  is described and explained in greater detail below based on  FIGS. 4A and 4B . 
     The valve  22  is depicted in  FIG. 4A  in its closed setting, analogous to  FIG. 3 . The discharge direction of the urine through the main channel  28  is indicated by an arrow  36 . An actuating element  40  for the valve  22 , designed as a piston, is disposed in a receiving section  38 , running transverse to the main channel  28 , having a cylindrical design and intersected by the main channel  28 . A closing section  42  of the actuating element  40  is located in the main channel  28 , in the closed setting depicted in  FIG. 4A , such that liquid can no longer be discharged through the main channel  28 . 
     When pressure is applied to the lower end  44  of the actuating element  40 , it is moved into the releasing setting depicted in  FIG. 4B . When in this releasing setting, liquid, or urine, respectively, can flow through the main channel  28  in the direction of the arrow  36 . The closing section  42  is moved thereby such that it no longer overlaps the main channel  28 , in contrast to  FIG. 4A . A releasing section  46  then overlaps the main channel  28 . This releasing section  46  has a clearly smaller outer diameter than the receiving section  38 . As a result, liquid can flow past the releasing section  46 , through the main channel  28 . 
     When a urine bag is being replaced, or after the bladder has been voided, respectively, the valve  22  for the urinary catheter can again be closed. For this, pressure should be exerted on the upper end  48  of the actuating element  40 . The actuating element  40  is again moved into the closed setting in the receiving section  38 . As a result, urine can no longer be discharged from the urinary catheter  10 , or through the opening  20  at the connecting section  18 . 
     Another embodiment of a valve  22  for a urinary catheter  10  is shown in  FIGS. 5A to 5C . The components and elements corresponding thereto in  FIGS. 4A and 4B  are indicated with corresponding reference symbols. The valve as shown in  FIGS. 5A to 5C  has three switching settings, wherein the valve  22  in  FIG. 5A  is depicted in a closed setting, analogous to the closed setting depicted in  FIG. 3  and  FIG. 4A . The discharge direction for the urine through the main channel  28  is likewise indicated by an arrow  36 . An actuating element  40  for the valve  22 , designed as a piston, is disposed in a receiving section  38 , running transverse to the main channel  28 , which is designed as a cylinder, and intersected by the main channel  28 . 
     In the closed setting depicted in  FIG. 5A , a closing section  42  of the actuating element is located in the main channel  28  such that liquid can no longer be discharged through the main channel  28 . An air-permeable filter and/or membrane section  50  is disposed beneath the closing section  42 . This filter and/or membrane section  50  is advantageously manufactured from a hydrophobic acrylate polymer, and cannot be permeated by liquids. 
     When pressure is applied to the lower end  44  of the actuating element  40 , it is first moved to the middle setting depicted in  FIG. 5B . The filter and/or membrane section  50  overlaps the main channel  28  when in the middle setting, such that air can be discharged through the main channel  28 , but, due to the non-liquid-permeable filter and/or membrane section  50 , a discharge of liquid can be prevented. As a result, air can be removed from a bladder of a patient in the middle setting. 
     If pressure is then applied to the lower end  44  of the actuating element  40 , it is moved to the open setting depicted in  FIG. 5C . Liquid, or urine, respectively, can flow in the direction of the arrow  36  through the main channel  28  when in this releasing setting. The closing section  42  is moved thereby, from the overlapping with the main channel  38 , analogously to  FIG. 4B . The releasing section  46  then overlaps the main channel  28 . This releasing section  46  has a significantly smaller outer diameter than the receiving section  38 . As a result, liquid can flow past the releasing section  46 , through the main channel  28 . A replacement of a urine bag can likewise occur, analogously to the valve  22  as shown in  FIG. 4A  and  FIG. 4B , after moving the valve into the closed setting. For this, pressure should be applied to the upper end  48  of the actuating element  40 , and the actuating element  40  is again moved in the receiving section  38 , into the closed setting. As a result, with a valve  22  as shown  FIGS. 5A to 5C  as well, urine can no longer be discharged from the urinary catheter  10 , or through the opening  20  at the connecting section  18 , respectively. 
     The invention has been described in an illustrative manner. It is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the invention may be practiced other than as specifically described.
A bladder catheter includes a tube, wherein the tube has an insertion section for inserting into a urinary bladder through a urethra and wherein the tube has a connection section for connecting connection elements, wherein fluid can be drained from the urethra at the connection section via the insertion section, wherein a closable valve is arranged between the insertion section and the connection section in such a way that the discharge of fluid from the connection section can be prevented while the valve is closed.