Sealing head for machines for heat treating threads

Abstract

The present invention relates to a sealing head for machines for heat treating threads, comprising a frame ( 1 ) fixed to a pressurised chamber through which a conveyor belt passes, a pair of horizontal rollers ( 2 and 3 ) placed on top of each other and pressed against the opposite faces of the conveyor belt and of seals ( 4 and 5 ) to form a sealed closure between the rollers ( 2 and 3 ) and the frame ( 1 ), at least one ( 2 ) of the horizontal rollers ( 2 and 3 ) and the seals ( 4 and 5 ) being connected to the corresponding movement actuators ( 6 to 8 ). Sealing head characterised in that the actuators ( 6 to 8 ) of the horizontal roller or rollers ( 2 and/or 3 ) and the seals ( 4 and 5 ) between the rollers ( 2 and 3 ) and the frame ( 1 ) are in the form of pneumatic actuators without pistons, namely of the balloon or bellows type.

1 - 12 . (canceled)  
   
   
       13 . Sealing head for machines for heat treating threads, comprising a frame fixed to a pressurized chamber through which a conveyor belt passes, a pair of horizontal rollers placed on top of each other and respectively pressed against opposite faces of the conveyor belt and of seals to form a sealed closure between the rollers and the frame, at least one of the horizontal rollers and the seals being connected to corresponding movement actuators, wherein the actuators for the horizontal roller or rollers and for the seals between the rollers and the frame are in the form of actuators without pistons, namely of the balloon or bellows type.  
   
   
       14 . Sealing head according to  claim 13 , wherein the actuators operate under a maximum usage pressure of approximately 8 bar.  
   
   
       15 . Sealing head according to  claim 13 , wherein the actuators that urge at least one of the two horizontal rollers on the conveyor belt against the other horizontal roller are dual-action diaphragm cylinders and are arranged on the frame, on either side of said horizontal rollers, and act on end regions of driving and guiding shaft or shafts of said horizontal rollers by means of sliding bearings guided in corresponding ends of the frame and cooperating with push rods connected between said sliding bearings and the corresponding diaphragms of the actuators.  
   
   
       16 . Sealing head according to  claim 13 , wherein each actuator for the roller or rollers is in the form of two single-action actuators of the balloon or bellows type, said two actuators each acting on either side, either of a bearing supporting a shaft of the corresponding roller, or on a movement means connected to said bearing.  
   
   
       17 . Sealing head according to  claim 13 , wherein the seals between the rollers and the frame, which consist for each roller of a thin sealing sheet mounted on a pivoting support resting on the frame by means of a longitudinal pivoting end stop, each cooperate with the corresponding actuator or actuators in the form of balloons or bellows by means of a load transfer rod mounted on the frame between the corresponding actuator and the pivoting support and loaded by a return spring.  
   
   
       18 . Sealing head according to  claim 13 , wherein the actuators for the seals between the horizontal rollers and the frame are balloon or bellows actuators and act on the seals, which are in the form of sealing plates, by means of a force transfer device in the form of an elbow lever mounted pivotally about a pin on the frame and actuated so as to pivot by means of a transmission rod comprising a return spring.  
   
   
       19 . Sealing head according to  claim 13 , wherein the actuators are pneumatic actuators.  
   
   
       20 . Sealing head according to any  claim 13 , wherein the actuators are hydraulic oil or aqueous fluid actuators.  
   
   
       21 . Sealing head according to  claim 13 , wherein the actuators are each provided with a drain valve and are controlled automatically, either by means of a programmable controller, or by means of a pneumatic controller using elements of pneumatic logic, standard logic or electropneumatic logic acting on regulating valves arranged in a supply circuit of the actuators.  
   
   
       22 . Control process for a heat treatment machine with sealing heads provided with actuators according to  claim 13 , wherein from an open position of the treatment chamber, the process comprises steps of temporarily closing the horizontal sealing rollers around the conveyor belt, then of aligning the horizontal sealing rollers by means of the seals, of next placing the horizontal sealing rollers under pressure against the conveyor belt, of then applying thin sealing sheets of the seals, under pressure, to the horizontal sealing rollers, of then applying seals, under pressure, against ends of the horizontal sealing rollers, of then pressurizing the treatment chamber, subject to authorization to start up delivered by contacts or sensors recording the closure of drain valves and the opening of regulating valves allocated to the actuators, a fall in pressure in the chamber or an order to open a sealing head causing control of the regulating valves to halt at the same time as opening of the drain valve of the chamber and issue of a signal prohibiting restarting, the actuators for controlling the thin sheets and the actuators for controlling the movement of one or both horizontal sealing rollers being then successively depressurized in order to return to the open position of the machine before a new treatment cycle.  
   
   
       23 . Control process according to  claim 22 , wherein the temporary closure of the horizontal sealing rollers round the conveyor belt is carried out simply by depressurizing dual-effect actuators in such a way that an upper one of the rollers falls under its own weight until said upper roller makes contact with the conveyor belt.  
   
   
       24 . Control process according to  claim 22 , wherein alignment of the horizontal sealing rollers by means of the seals, after temporary closure of the horizontal sealing rollers round the conveyor belt, is carried out by a series of pressurizations and de-pressurizations of the actuators acting on the seals.