Device For Insertion, Guidance And Evacuation Of Cylindrical Parts Such As Nuclear Fuel Pellets, In A Centreless Grinder

Abstract

The invention relates to a device ( 1 ) for the insertion, guidance and evacuation of cylindrical parts to be ground in a centreless grinder ( 10 ). According to the invention, micrometric means ( 4, 40, 41 ) for adjustment of the alignment of the guides at the entry ( 3 ) to and the exit ( 5 ) from the guide chute ( 2 ) are provided and these micrometric adjustment means are independent from each other. The invention enables very precise adjustment of the alignment and prevents any shift of the parts.

1 . Device for the insertion, guidance and evacuation of cylindrical parts such as nuclear fuel pellets, in a centreless grinder, comprising:
 an insertion guide chute adapted to guide said cylindrical parts over the length of the grinding wheel and drive wheel of a centreless grinder,   a first guide, called the entry guide, arranged at one longitudinal end of the guide chute and adapted to allow the insertion of cylindrical parts one by one onto the guide chute from a conveyor system on the entry side of the centreless grinder,   mechanical means for micrometric adjustment of the entry guide relative to the guide chute,   a second guide, called the exit guide, arranged at the other longitudinal end of the guide chute and adapted to transfer parts from the chute to a conveyor system on the exit side from the centreless grinder,   mechanical means for micrometric adjustment of the alignment of the exit guide relative to the guide chute,   
       wherein the mechanical means for micrometric adjustment of the alignment of the entry guide are independent from the micrometric alignment means of the exit guide. 
     
     
         2 . Device according to  claim 1 , in which the guide chute is a single piece part made of XC 38 steel, on which surface and in-core annealing and quenching heat treatments have been made and preferably surface treatments once the guide chute has been finished. 
     
     
         3 . Device according to  claim 1 , in which at least one of the two guides is composed of two strips one of which is fixed and parallel to the longitudinal edge of the chute and the other is installed on a pivot that adjusts the space from the fixed guide facing it, the distance from the pivoting guide being varied by actuation of mechanical means for adjusting the alignment of said guide. 
     
     
         4 . Device according to  claim 3 , in which the entry guide and the exit guide are each composed of two strips, one of which is fixed and parallel to a longitudinal edge of the chute and the other is free to pivot to adjust the spacing of the guide from the fixed guide facing it. 
     
     
         5 . Device according to  claim 3 , in which the pivoting strip of the two guides is installed pivoting about an axis fitted with a polymer bearing. 
     
     
         6 . Device according to  claim 4 , in which:
 the pivot axis of the pivoting strip of the entry guide and/or the exit guide is (are) mounted in a support,   the mechanical micrometric means for adjustment of the alignment of the entry guide relative to the guide chute and/or the mechanical adjustment means of the exit guide comprise a first screw screwed into the pivot axis support and a second screw nested into the first screw, with a smaller pitch than the first screw and adapted to bear in contact with a part of the pivoting strip, screwing of the first screw into the support causing translation of the two screws while screwing the second screw into the first screw and bearing in contact with the part of the pivoting strip causes pivoting of the pivoting strip.   
     
     
         7 . Device according to  claim 6 , in which the pitch of the second screw is smaller than but sufficiently close to the pitch of the first screw to create a micrometric adjustment of the pivoting strips. 
     
     
         8 . Device according to  claim 6 , comprising a spring adapted to compensate for functional clearances of the device by guaranteeing permanent bearing between the second screw and the pivoting strip. 
     
     
         9 . Device according to  claim 7 , in which each pivot axis and screw axis support is fixed to the guide chute. 
     
     
         10 . Device according to  claim 7 , in which each pivot axis and screw axis support is shaped in a turret with the two screws nested in each other and arranged in the upper part of the turret. 
     
     
         11 . Device according to  claim 1 , in which the geometric shape and the length of the exit guide are adapted to limit the number of ground cylindrical parts buffered at the exit from the wheels. 
     
     
         12 . Device according to  claim 1 , forming a single piece assembly to which adapted handles are fixed to enable its insertion into and removal from a centreless grinder. 
     
     
         13 . Centreless grinder comprising:
 an insertion guide chute adapted to guide said cylindrical parts over the length of the grinding wheel and drive wheel of a centreless grinder,   a first guide, called the entry guide, arranged at one longitudinal end of the guide chute and adapted to allow the insertion of cylindrical parts one by one onto the guide chute from a conveyor system on the entry side of the centreless grinder,   mechanical means for micrometric adjustment of the entry guide relative to the guide chute,   a second guide, called the exit guide, arranged at the other longitudinal end of the guide chute and adapted to transfer parts from the chute to a conveyor system on the exit side from the centreless grinder,   mechanical means for micrometric adjustment of the alignment of the exit guide relative to the guide chute,   
       wherein the mechanical means for micrometric adjustment of the alignment of the entry guide are independent from the micrometric alignment means of the exit guide. 
     
     
         14 . Centreless grinder according to  claim 13 , adapted to grinding of nuclear fuel pellets (P). 
     
     
         15 . Glove box in which a centreless grinder is arranged according to  claim 13 . 
     
     
         16 . Device for the insertion, guidance and evacuation of cylindrical parts such as nuclear fuel pellets, in a centreless grinder, comprising:
 an insertion guide chute adapted to guide said cylindrical parts over the length of the grinding wheel and drive wheel of a centreless grinder,   a first guide, called the entry guide, arranged at one longitudinal end of the guide chute and adapted to allow the insertion of cylindrical parts one by one onto the guide chute from a conveyor system on the entry side of the centreless grinder,   a first plurality of screws for micrometric adjustment of the entry guide relative to the guide chute,   a second guide, called the exit guide, arranged at the other longitudinal end of the guide chute and adapted to transfer parts from the chute to a conveyor system on the exit side from the centreless grinder,   a second plurality of screws for micrometric adjustment of the alignment of the exit guide relative to the guide chute,   
       wherein the first plurality of screws for micrometric adjustment of the alignment of the entry guide are independent from the second plurality of screws for micrometric alignment means of the exit guide. 
     
     
         17 . Device according to  claim 15 , in which the first plurality of screws and/or the second plurality of screws comprise a first screw and a second screw nested into the first screw.