Methods for the preparation of dhea derivatives

Abstract

An apparatus for shaping a flexible web ( 2 ) includes, between an entry roller ( 5 ) and a forming roller ( 3 ), a regulating module ( 7 ) provided with a starting roller ( 13 ) designed to control the movement and the speed of the web upstream of the shaping roller ( 3 ) and at least one mobile guide element ( 9 ) designed to exert, at least on one buffer loop ( 8 ) of the web ( 2 ) formed between the rollers ( 5, 3 ), a positive guiding thereof, in accordance with a law of displacement which is a function of the length of the buffer loop ( 8 ) in operation.

1 . Apparatus for shaping a web ( 2 ) made of a flexible material, comprising at least one feed roll ( 5 ,  5 ′) adapted to deliver the web ( 2 ) continuously in accordance with a law of given displacement (X e ) and speed (V e ), a shaping roll ( 3 ) associated with a counterpart roll ( 3 ′) adapted to shape the web over at least a part of its peripheral length, this shaping roll being constituted by a support roll ( 3   a ) on which at least one interchangeable shaping element ( 3   b ) is added, fixed on its outer surface, and which is animated by a movement of rotation in accordance with a law of given displacement (X c ) and speed (V c ), characterized in that it comprises, between the feed roll ( 5 ) and the shaping roll ( 3 ), a regulating module ( 7 ) provided with take-off means ( 13 ,  13 ′;  9 ,  9 ′) adapted to control the displacement (X n ) and the speed (V n ) of the web ( 1 ) upstream of the shaping roll ( 3 ) and at least one mobile guide element ( 9 ,  9 ′) adapted to exert on at least one buffer loop ( 8 ) of the web ( 2 ) formed between said rolls ( 5 ,  3 ), a positive guiding of which the displacement is controlled in accordance with a determined law.  
   
   
       2 . Apparatus according to  claim 1 , characterized in that the law of displacement of the mobile guide element ( 9 ,  9 ′) of the web ( 2 ) is a function of the law of displacement (X e ) of the feed roll ( 5 ,  5 ′) and of the law of displacement (X n ) of the take-off means ( 13 ,  13 ′), itself a function of the law of displacement (X c ) of the shaping roll ( 3 ).  
   
   
       3 . Apparatus according to  claim 1 , characterized in that the take-off means are constituted by at least one roll ( 13 ,  13 ′).  
   
   
       4 . Apparatus according to  claim 1 , characterized in that the take-off means are constituted by the mobile guide element ( 9 ), the latter being formed by a rotating roll around which the web ( 2 ) winds; at least one rotating roll ( 13 ,  13 ′) animated by a peripheral speed greater than that of the web ( 2 ) being disposed between the shaping roll ( 3 ) and the guide roll ( 9 ).  
   
   
       5 . Apparatus according to  claim 2 , characterized in that the guide element ( 9 ) is constituted by a rotating roll around which the web ( 2 ) winds.  
   
   
       6 . Apparatus according to  claim 2 , characterized in that the guide element ( 9 ) is constituted by a piece ( 9 ′) fixed in rotation, around which the web ( 2 ) winds.  
   
   
       7 . Apparatus according to  claim 6 , characterized in that the guide element ( 9 ′) is provided with means for blowing a gas adapted to create between itself and the web ( 2 ) a cushion of gas.  
   
   
       8 . Apparatus according to  claim 1 , characterized in that the displacement of the guide element ( 9 ,  9 ′) is linear.  
   
   
       9 . Apparatus according to  claim 8 , characterized in that the linear displacement of the guide element ( 9 ,  9 ′) is obtained by a linear motor comprising primary and secondary poles mobile with respect to each other and means for controlling their relative movements, the guide element ( 9 ,  9 ′) being fast with one of these poles.  
   
   
       10 . Apparatus according to  claim 8 , characterized in that the linear displacement of the guide element is obtained by a system constituted by a connecting rod ( 10 ) articulated at one of its ends on the latter and at its other end on a crank ( 12 ) whose angular position determines the linear function of the guide element ( 9 ′).  
   
   
       11 . Apparatus according to  claim 1 , characterized in that the displacement of the guide element ( 9 ,  9 ′) is circular.  
   
   
       12 . Apparatus according to  claim 11 , characterized in that the guide element is constituted by a guide roll ( 9 ) arranged so that it is adapted, in the course of its displacement, to remain tangential to another roll ( 24 ,  13 ), the web ( 2 ) being admitted between these rolls ( 9 ,  24 ,  13 ) and winding around the latter in order then to go in the direction of the shaping roll ( 3 ).  
   
   
       13 . Apparatus according to  claim 12 , characterized in that said other roll is constituted by a regulating roll ( 24 ).  
   
   
       14 . Apparatus according to  claim 12 , characterized in that said other roll is constituted by the take-off roll ( 13 ).  
   
   
       15 . Apparatus according to  claim 13 , characterized in that the circular displacement of the guide ( 9 ) and regulating ( 24 ) rolls ensures control of position (X n ) and of speed (V n ) of the web upstream of the shaping roll ( 3 ).  
   
   
       16 . Apparatus according to  claim 12 , characterized in that the guide roll ( 9 ) and said other roll are servo-controlled by each other in rotation.  
   
   
       17 . Apparatus according to  claim 1 , characterized in that it comprises, between the feed roll ( 5 ) and the take-off means ( 13 ), a system ( 11 ) for controlling the tension of the web.  
   
   
       18 . Apparatus according to  claim 17 , characterized in that the feed roll ( 5 ) is servo-controlled by the system for controlling the tension of the web so as to ensure maintenance of the tension of the latter at a constant value.  
   
   
       19 . Apparatus according to  claim 1 , characterized in that it comprises means adapted to read a cyclic mark disposed on the web, to compare the position thereof with a reference of position of the shaping roll and, as a function of this comparison, to modify the positioning of the web with respect to the shaping roll.