Patent Publication Number: US-10315203-B2

Title: Outlet nozzle for a centrifuge drum

Description:
This application claims the priority of International Application No. PCT/EP2013/075300, filed Dec. 3, 2013, and German Patent Document No. 10 2012 111 801.9, filed Dec. 5, 2012, the disclosures of which are expressly incorporated by reference herein. 
     BACKGROUND AND SUMMARY OF THE INVENTION 
     The invention relates to an outlet nozzle for a centrifuge drum. 
     Outlet nozzles of the prior art are disclosed in DE 39 22 619 C1, DE 41 05 903 A1, and U.S. Pat. No. 2,560,239. 
     Moreover, an outlet nozzle of the generic type is also disclosed in DE 195 27 039 C1. According to the teachings of DE 195 27 039 C1, the diameter of the entry opening of the outlet nozzle in the region of the nozzle body is either of identical size to the diameter of the outlet duct, is larger by a maximum of 50 percent or is smaller by 50 percent than the diameter of the outlet duct. Moreover, the inlet space steadily increases up to a maximum diameter. The diameter of the outlet duct in the nozzle brick initially tapers down to a bottleneck, and then in the case of one of the variants of DE 195 27 039 C1 widens out in a conical manner by an angle of at least 5°. 
     The outlet nozzle per se has indeed proven to be successful. 
     However, it is nevertheless desirable for the blocking tendency of the outlet nozzle to be further reduced and for the exit jet to be positively influenced. The solution to this issue is the object of the invention. 
     Accordingly, the narrowest point of the outlet duct in terms of cross section is formed by the entry opening per se, and it is provided that the cross section of the outlet duct across preferably the entire axial length of the outlet duct in the exit direction is not decreased at any point, apart from a production radius on the inlet which may optionally be provided. 
     The blocking tendency and the nozzle jet formation are in this manner reduced by a modification of the design embodiment of the outlet duct of the nozzle brick, which is implementable in a simple manner. 
     Advantageous design embodiments may be derived from the dependent claims. 
     In the following the invention is described in more detail by means of an exemplary embodiment with reference to the figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a cross section of an outlet nozzle according to the invention; 
         FIG. 2  shows a schematic illustration of a known separator drum; 
         FIGS. 3-6  show further outlet nozzles according to the invention, with and without a nozzle brick. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
       FIG. 2  shows a biconical separator drum  100  which is conceived for continuous operation. 
     The separator drum  100  has a vertical rotation axis. In the conical or even biconical separator drum  100 , respectively, a stack  300  of conical separator plates  400  is disposed in the spinner space  200 . The separator plates  400  are disposed on a distributor shaft  600 . A supply pipe  500  serves for supplying a product to be processed to distributor ducts  700 . 
     The distributor ducts  700  open out into the spinner space  200  in which the product is clarified of solids and optionally separation into two or more liquid phases of various density is performed. One or a plurality of drains  900 , which may be provided with peeling disks, for liquid phases serve to discharge the at least one liquid phase. In contrast thereto, the solids are evacuated from the separator drum  100  to the outside by exit openings  800  which are distributed along the circumference, preferably in the region of the largest circumference of the separator drum. To this end, in each case one outlet nozzle  1  is inserted into the exit openings  800 . 
       FIG. 1  shows a first preferred embodiment of the outlet nozzle  1  according to the invention. 
     The outlet nozzle  1  has a nozzle body  2 , which is configured as a nozzle holder, and a nozzle brick  3  which is inserted into the nozzle body  2 . 
     An axially running inlet duct  4  is configured in the nozzle body  2 , and an outlet duct  7  extending at an obtuse angle to the inlet duct is configured in the nozzle brick  3 . The symmetry axis  5  of the inlet duct  4  and the symmetry axis  6  of the outlet duct  7  of the nozzle brick  3  are oriented so as to be angled in relation to one another, wherein the thus enclosed angle is an obtuse angle “α” to which preferably the condition 90°&lt;α&lt;160° applies. 
     The outlet duct  7  in the nozzle brick  3  has an entry opening  8  and an exit opening  10  which is spaced apart from the former by an axial distance z in the exit direction A. 
     Proceeding from the entry opening, the outlet duct  7  widens up to the diameter of the exit opening  10 , that is to say that the diameter of the outlet duct  7  in the nozzle brick  3  increases from the entry opening  8  up to the exit opening  10 . 
     The narrowest point of the outlet duct  7  of the nozzle brick  3  in terms of the cross section is in this manner formed by the entry opening  8  per se of the nozzle brick  3 , wherein the cross section of the exit opening  10  according to the invention is always larger than the cross section of the entry opening  8  of the outlet duct  7  of the nozzle brick  3 . Preferably, the cross section of the outlet duct  7  across the axial length of the outlet duct  7  in the exit direction A is not decreased at any point. This results in a reduced blocking tendency and improved focusing of the jet. 
     The nozzle brick  3  preferably is a component which is rotationally symmetrical across its entire length, simplifying the manufacture of the same in comparison with the prior art of the generic type. The nozzle brick  3  is preferably configured so as to be planar and flat on the axial end side thereof in the region of the entry opening. 
     A solder  11  for fastening the nozzle brick on the nozzle body is preferably located between the nozzle body  2  and the nozzle brick  3  on the outer circumference of the nozzle brick  3 . Alternatively, a seal (which engages in an annular groove, for example, not illustrated here) may also be provided in this region if the nozzle brick  3  is to be releasable (for example when the latter is to be held in the nozzle body  2  by way of threads).  FIG. 3  shows a nozzle body  2  of this type which is configured as a nozzle holder, with a nozzle brick  3  (similar to  FIG. 1 ). According to the exemplary embodiment of  FIG. 3 , the nozzle brick  3  may be screwed into the nozzle holder  2 . Here, the seal between the outer circumference of the nozzle body  3  and the nozzle holder is not drawn in  FIG. 3 . 
     Here,  FIGS. 1 and 3  show solutions having a nozzle body  2  which is configured as a nozzle holder and into which the nozzle brick  3  is inserted, and  FIGS. 4 to 6  show solutions in which a nozzle brick  3  is dispensed with. Instead, the outlet duct  7  which runs at an obtuse angle to the inlet duct  4 , according to  FIGS. 4 to 6  is directly configured in the nozzle body  2  per se, which then is in one part (wherein in this case a sufficiently hard material is used for manufacturing the nozzle body  2 ). On account thereof, regions in which contamination may build up can be reduced even further. 
     The outlet duct  7  in all exemplary embodiments widens out continuously or in portions across its axial length. If and when a nozzle brick  3  is present ( FIG. 1 ), the outlet duct  7  preferably widens out in a conical manner across its axial length. 
     As already explained, the outlet duct  7  preferably widens out in a constant and steady manner across its entire axial length. This is advantageous but is not mandatory. The cross section of the outlet duct  7  which in the cross section preferably is circular may indeed increase in a non-uniform manner across the axial length of the outlet duct  7 , or else not increase in a first internal region having a length y ( FIG. 3 : nozzle body with nozzle brick,  FIG. 4 : nozzle body without nozzle brick), such that the diameter of the outlet duct  7  in this first region of the entry opening is constant across the axial distance y (diameter D 1 ), which diameter D 1  of the outlet duct  7 , which in this portion in the cross section preferably is circular, is adjoined in the exit direction by the widening exit cone  9 , the largest diameter D 2  of which is larger than the diameter D 1  ( FIGS. 3 to 6 ). 
     In the region of the entry opening  8  the outlet duct  7 , on the preferably circular circumferential periphery may have an encircling production radius R 1 . The latter may have a very sharp edge (i.e. the radius R 1  is negligibly small and may be set to zero), or rather be somewhat larger (preferably less than 3 mm, in particular less than 1 mm). The production radius R 1  preferably is dimensioned in such a manner that it extends across less than 10% of the axial extent z of the outlet duct  7 . The radius R 1  preferably transcends into that region of the outlet duct  7  in which the latter has its smallest diameter D 1 . The production radius  7  reduces wear on the entry opening  8  of the outlet duct  7 . 
     According to  FIG. 6 , a second radius R 2  (which is aligned so as to widen out in the outflow direction) adjoins the production radius R 1 , which radius R 2  is designed in such a manner that a transition in the form of a sharp edge in the region of the transition from the production radius R 1  to the widening cone  9  is avoided. 
     Seals  12  on the outer circumference of the nozzle body  2  seal the outlet nozzle  1  in relation to the drum wall. Furthermore, a thread  13  enables the nozzle body  2  to be screwed into the drum wall or into the openings  800  in the drum wall, respectively. A bayonet catch or similar is also conceivable. 
     The design embodiment of the outlet duct  7 , preferably in the nozzle brick  3 , is particularly advantageous in all exemplary embodiments. Since the outlet duct  7  from the region of the entry opening  8  up to the region of the exit opening  10  does not taper down anywhere, but since the outlet duct  7  from the entry opening  8  up to the exit opening  10  continuously opens up in a conical manner (if applicable, up to the mentioned production radius), a significantly lower blocking tendency in comparison with the prior art is achieved, in particular also when the consistency of the product to be processed changes. 
     Preferably, the angle of inclination β of the conical region  9  of the outlet duct  7  in relation to the symmetry axis  6  of the outlet duct  7  is 5° to 45°, in particular 10° to 30°, and particularly preferably 30° to 45°. In this range, the blocking tendency is reduced in a particularly significant manner. 
     Preferably, the diameter of the outlet duct  7  increases by more than 50%, in particular more than 75%, across its axial length, on account of which particularly good operational behavior is achieved. 
     The inlet duct  4  does not widen out in a conical manner, as in the prior art, but it initially tapers down in a uniform manner to a constant diameter which extends across the major part of the axial length of the inlet duct, or the inlet duct  4 , respectively. 
     As already mentioned, according to  FIG. 4 , no nozzle brick  3  is provided in the nozzle body  2 , but is configured in the nozzle body per se so as to be one part therewith, wherein the latter has the axially running inlet duct  4  and the outlet duct  7  which runs at an obtuse angle to the inlet duct and which has the entry opening  8  and the exit opening  10 , wherein the diameter of the outlet duct  7  increases in portions in such a manner that the narrowest point of the outlet duct  7  in terms of cross section is formed by the entry opening  8  per se, wherein the cross section of the outlet duct  7  across the axial length of the outlet duct  7  in the exit direction A is not decreased at any point. If and when a sufficiently hard material is selected, the nozzle brick made from a harder material than the material of the nozzle holder may be dispensed with. 
     The absolute nozzle diameter D 1  on the entry opening  8  depends on the consistency of the solid phase of the product to be processed. The diameter D 1  is selected by way of experiment in such a manner that a constant exit flow from the outlet nozzle is formed. Preferably, the following applies to the diameter D 1 : 0.5 mm&lt;=D 1 &lt;=5 mm. 
     Preferably, the ratio of the axial length y of the portion of the outlet duct having a constant diameter to the entire axial length z of the exit duct  7  fulfills the following condition: y/z&lt;=½. 
     The absolute nozzle diameter D 2  on the exit opening preferably is significantly larger than the diameter Dl on the entry opening  8 , in particular is at least twice the size. 
     Furthermore preferably, the axial length z of the exit duct fulfills the following condition: 4 mm&lt;=z&lt;=30 mm. Moreover, it is advantageous for the ratio of the axial length y of a portion of the exit duct having a constant diameter to the diameter to fulfill the following condition: 1&lt;=y/D 1 &lt;=5. 
     In these ranges, particularly good operational behavior is in each case achieved. 
     LIST OF REFERENCE SIGNS 
     Outlet nozzle  1   
     Nozzle body  2   
     Nozzle brick  3   
     Inlet duct  4   
     Symmetry axis  5   
     Symmetry axis  6   
     Outlet duct  7   
     Entry opening  8   
     Exit cone  9   
     Exit opening  10   
     Solder  11   
     Seal  12   
     Thread  13   
     Spinner drum  100   
     Spinner space  200   
     Stack of separator plates  300   
     Separator plate  400   
     Supply pipe  500   
     Distributor  600   
     Distributor duct  700   
     Opening in drum wall  800   
     Drain  900   
     Angle α, β 
     Diameter D 1 , D 2   
     Radii R 1 , R 2   
     Lengths y, z