Patent Publication Number: US-2004057846-A1

Title: Eccentric screw-type pump with spare unit

Description:
[0001] The present invention relates to an eccentric screw-type pump comprising a helical rotor that rotates in a helical stator chamber as well as a driving shaft that connects the rotor to a drive system.  
       [0002] In correspondence with the generally common prior art according to the pamphlet by NETZSCH “The heart of your process”, pages 18 and 19, and the European Patent EP 0 657 649 A1 and the German Patent DE 24 58 839 A1, the rotors in screw-type pumps are connected via articulation means to the gear unit or driving system, respectively. Pin joints, pin-type cardan universal joints, curved-tooth joints and flexible rods may be used as articulating means. The replacement of a rotor or of the articulation means always requires time-consuming mounting operations.  
       [0003] The present invention is hence based on the problem of reducing the mounting time required for replacement of parts of the rotor, the stator or the joint, specifically at the customer&#39;s site.  
       [0004] In accordance with the present invention, this problem is solved by the features of claim 1.  
       [0005] Expedient improvements of the invention are evident from the features defined in the dependent claims.  
       [0006] Specifically in the case of repair work carried out at the customer&#39;s site or by the customer, it is desirable that the exchange of parts can be handled in a minimum of time with the simplest means possible. To this end, the invention proposes that the driving shaft should be connected via a separable connector in the form of a screw, a clamping element or comparable elements to the drive system or its interposed gear set.  
       [0007] With the stator being clamped by means of a stay-bar arrangement between lateral flanges, it may be expedient, according to the present invention, that the pump casing is split and that its parts are connected to each other by means of a quick-action device or a quick coupler. In this inventive configuration, one removes and replaces the complete stator and one part of the pump casing together with the driving shaft, the joints or the flexible shaft, respectively, and the seal.  
       [0008] In accordance with another expedient configuration of the invention, the application of a gear unit (e.g. a flat gear set) is provided. The gear set is equipped with a hollow shaft. This hollow shaft accommodates the rotor-driving shaft that is supported and sealed in the pump casing. A screw ensures the axial fixation of the driving shaft relative to the hollow shaft. The torque is transmitted via a shaft-hub connector, e.g. a key-and-feather connector. 
     
    
    
     [0009] One embodiment of the invention is illustrated in FIG. 1.  
     [0010]FIG. 1 shows an eccentric screw-type pump  10  of the Moineau type, which comprises a drive unit  12  and a gear set  14  that is connected via a hollow shaft to a driving shaft  16 . 
    
    
     [0011] The driving shaft  16  is provided with a seal  18  that prevents the product from penetrating into the region of the bearing  20 . The flexible shaft  22  and the driving shaft  16  are fixed to each other by means of a screw connector, a shrinking connection or an adhesive joint so as to prevent them from rotating relative to each other. The pump casing  26  is provided with an inlet tubulure  28  through which the product is aspirated into the eccentric screw-type pump  10 . It is possible to unscrew the screw  30  and to open the quick-action clamping device  32  for simultaneous removal of the entire stator  38 , the terminating tubulure  34 , the rotor  36 , the flexible shaft  22 , the driving shaft  16  and the seal  18  as a single unit from the pump casing  26  and the drive unit  12  for replacement of the spare or exchange unit.  
     LIST OF REFERENCE NUMERALS  
     [0012] 10  eccentric screw-type pump  
     [0013] 12  drive system  
     [0014] 14  gear set  
     [0015] 16  driving shaft  
     [0016] 18  seal  
     [0017] 20  bearing  
     [0018] 22  shaft  
     [0019] 26  pump casing  
     [0020] 28  inlet tubulure  
     [0021] 30  screw  
     [0022] 32  quick-action clamping device  
     [0023] 34  terminating tubulure  
     [0024] 36  rotor  
     [0025] 38  stator  
     [0026] 40  intermediate tube