Apparatus for processing fabric

Abstract

A method and apparatus for supplying liquid mixtures on a mix-on-demand basis for consumptive use, and for maintaining the composition of such mixture on a highly accurate and stable basis. For wet-on-wet processing of fabrics, the processing solution is supplied at start-up on a mix-on-demand basis to precise specifications and is maintained at such precise specifications throughout fabric processing, which involves continuous additions of water by the incoming fabric and removal of solution by the exiting fabric. Recirculation of the solution at a high rate, together with rapid and repetitive measurements of the composition of the recirculating solution enables the solution to be precisely monitored and maintained. Periodic small additions of chemical are injected as necessary to maintain highly stable, accurately controlled process conditions. Extraordinary economies, both direct and indirect, can be realized with the new system.

1 - 16 . (canceled) 
     
     
         17 . Apparatus for accurately controlling the composition of a liquid fabric processing solution comprised of water and a processing chemical to maintain the water and chemical components thereof at predetermined proportions during consumptive use of said processing solution, which comprises,
 (a) a processing container for holding a limited quantity of said processing solution,   (b) one or more guide elements for progressively guiding an elongated moving web of wet fabric in a continuous manner into the through said processing container and for processing said fabric while in said container to continuously and progressively impregnate said fabric with said processing solution,   (c) the processing of said wet fabric resulting in the consumption from said processing solution of water and processing chemical in proportions different than said predetermined proportions,   (d) a recirculating system having an upstream portion at an outlet of said processing container and a downstream portion at an inlet to said processing container, including a pump, for continuously extracting processing solution from the processing container and returning solution back to the container at a volumetric rate per minute which is greater than said quantity normally held in said container,   (e) a sensor positioned in said recirculating system for optical exposure to the processing solution flowing therethrough and operative to rapidly, repetitively and accurately sense the proportion of processing chemical in said solution, and   (f) a valve-controlled supply associated with said recirculating system and controlled by said sensor for controllably introducing finite incremental quantities of processing chemical into said processing solution to at all times maintain said processing solution substantially to said predetermined proportions,   (g) said valve-controlled supply being positioned at a point in said recirculating system upstream of said sensor.   
     
     
         18 . Apparatus according to  claim 17 , wherein
 (a) said sensor comprises a sensor having an optical element in contact with the flowing processing solution, a light source directed at said processing solution, and means for sensing reflected and refracted light from said processing solution and generating therefrom an output signal indicative of the concentration of processing chemical in said processing solution.   
     
     
         19 . Apparatus according to  claim 17 , wherein
 (a) said valve-controlled supply is connected to said recirculating system upstream of said pump, and   (b) said pump is located upstream of said sensor.   
     
     
         20 . Apparatus according to  claim 19 , wherein
 (a) a static mixer is incorporated in said recirculating system, at a position downstream of said valve-controlled supply and upstream of said sensor.   
     
     
         21 - 26 . (canceled) 
     
     
         27 . Apparatus for chemical processing of elongated, moving fabric webs in a continuous manner, which comprises
 (a) a supply of fabric in elongated web form,   (b) a first stage processor, positioned to progressively receive the fabric web from said supply and including a body of water, to progressively impregnate successive portions of a continuously moving fabric web with water and including a roller pair for extracting excess water from the fabric to achieve a desired, substantially uniform water content in said fabric,   (c) a treatment processor positioned to receive moving fabric web from said first stage processor and to progressively impregnate successive portions of said moving fabric with a predetermined processing solution comprising a processing chemical and water and including a roller pair for extracting excess processing solution from the fabric to achieve a uniform and predetermined solution content in said fabric,   (d) said treatment processor including a solution pan for containing processing solution and having a working volume which is small in relation to a width of the fabric web and having a guide element at least partly submerged in said solution for guiding and directing the moving fabric web into and through said processing solution,   (e) a solution recirculating system having an inlet for withdrawing solution from said pan and an outlet for discharging solution into the pan,   (f) a recirculation pump in said recirculating system and having an operating flow capacity, in relation to the working volume of said solution pan, such that the entire volume of solution in said pan is recirculated multiple times per minute during operation of said apparatus,   (g) an optical sensor positioned in said recirculating system at a point to have direct optical exposure to processing solution flowing through said recirculating system and being operative to make rapidly repetitive optical measurements of the flowing solution to determine the composition thereof,   (h) a first valve-controlled supply of said processing chemical connected to said recirculating system and operative in response to said sensor to introduce finite incremental quantities of processing chemical into the flowing processing solution to maintain a predetermined proportion of said processing chemical in said processing solution, and   (i) a mixing device in said recirculating system, positioned downstream of the connection thereto of said first valve-controlled supply.   
     
     
         28 . An apparatus according to  claim 27 , wherein said optical sensor is positioned downstream of said connection and said mixing device whereby an introduced quantity of processing chemical is thoroughly mixed into the flowing solution in the recirculating system before said solution is exposed to said optical sensor. 
     
     
         29 . An apparatus according to  claim 27 , wherein
 (a) said first valve-controlled supply is connected to said recirculating system upstream of said pump, and   (b) said mixing device comprises said pump.   
     
     
         30 . An apparatus according to  claim 27 , wherein said mixing device is a static mixer positioned in said recirculating system at a point upstream of said optical sensor and downstream of the connection of said first valve-controlled supply. 
     
     
         31 . An apparatus according to  claim 29 , wherein said mixing device further comprises a static mixer positioned in said recirculating system. 
     
     
         32 . An apparatus according to  claim 31 , wherein said static mixer is positioned upstream of said pump. 
     
     
         33 . An apparatus according to  claim 27 , wherein
 (a) a solution level sensor is associated with said solution pan and operative to sense desired minimum and maximum levels of said processing solution,   (b) a second valve-controlled supply connected to said recirculating system upstream of said mixing device for the introduction of finite incremental quantities of water into the flowing processing solution,   (c) said first and second valve controlled supplies being operative, in response to said solution level sensor detecting said minimum level of said solution, to effect multiple finite incremental replenishing injections from the respective valve controlled supplies into the recirculating system,   (d) said first and second valve controlled supplies being so controlled as to inject both water and processing chemical in respective proportions to combine into the desired proportions of said processing solution.