Hose pump
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to a peristaltic or hose pump, and in particular to a pump for drawing flushing liquids and stone or tissue particles out of bodily cavities. 
     The pump hoses of such hose pumps are easy to cleanse and disinfect or are replaced by new hoses, exactly like the connecting hoses. 
     During the cleansing and disinfecting operations, the connecting hoses have to be released from the pump hose and reconnected thereafter, so that if operating instructions are disregarded, it is possible to confuse the connectors and to perform a wrong insertion into the pump housing, which represents a considerably danger to the patients. This risk also prevails when soiled hoses are being replaced by new hoses. 
     SUMMARY OF THE INVENTION 
     The object of the invention consists in assuring in the case of hose pumps of the kind referred to in the foregoing, that the pump hose may be inserted into the pump housing only with the suction and pressure sides in the correct positions, and that the coupling hoses may be connected to the suction and pressure sides of the pump hose in the correct manner, only. In accordance with the invention, this problem is resolved in that the two extremities of the hose which is to be placed in the pump housing comprise different coupling and plug elements for suction and pressure hoses which are to be connected and different projections or plug configurations which fit into complementary recesses of the pump housing or of the plug elements. Thanks to this solution, an erroneous insertion of the pump hose into the pump housing cannot occur in any case, and the coupling hoses may moreover be joined to the suction and pressure sides of the pump hose in the correct position only. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A specific embodiment of the invention is described in the following with reference to the drawing, in which an example of a hose pump in accordance with the invention is illustrated together with coupling hoses, in perspective and with its parts disassembled. 
    
    
     The pump housing 1 of the hose pump comprises two reception seats 2 and 3 for the two coupling extremities or connectors 4 and 5 of a flexible pump hose 6 which is to be inserted into the housing 1, and which operates in conjunction with a revolving pumping roller 7 by means of which fluid is forced through the hose. The two coupling elements 4 and 5 are differently formed, so that the coupling element or inlet connector 4 may be coupled only to a coupling element 4a of a suction hose 8, and the coupling element or outlet connector 5 may be coupled only to a coupling element 5a of a pressure-side hose 9, thereby preventing erroneous connections. 
     So that an erroneous interchange between the coupling extremities 4 and 5 may complementarily also be made impossible in the reception seats 2 and 3 of the pump housing 1, the coupling element 4 is provided with a projection 10 for engagement PG,4 in a recess bore 11 of the inlet seat 2, and the coupling element 5 is provided with a bore 12 for engagement of a pin 13 of the outlet seat 3. This provides the assurance that an erroneous insertion of the pump hose 6 into the pump housing 1, as well as that an erroneous connection of the suction and pressure-side hoses 8 and 9 to the coupling extremities 4 and 5 of the pump hose 6, cannot occur. The suction side of the hose pump is moreover connected via the hose 8 and a receiving vessel to an instrument which is to be introduced into a bodily cavity, these connecting elements also being co-ordinated with each other in a fool-proof and unmistakable manner by appropriately formed coupling and plug configurations. 
     Although the invention has been described in relation to a pump for drawing flushing liquids and the like from bodily cavities, it will be understood that the invention is equally applicable to hose pumps used in other fields.