Filter system for viscous or highly viscous liquids, in particular plastic melts and method for filtering viscous or highly viscous liquids

Abstract

A device and a method for filtering viscous or highly viscous liquids, in particular plastics melts, includes use of an oscillating filter plate.

1 . A filter system comprising:
 a filter chamber which defines an active filter area in a filter zone;   at least one cleaning chamber connected to the filter chamber;   a filter plate arranged in the filter chamber, the filter plate being at least twice as wide as the active filter area; and   a filter support plate arranged in the filter chamber, the filter plate being supported by the filter support plate,   wherein the filter plate is movable to the at least one cleaning chamber to clean the filter plate,   wherein either (i) the filter plate is guided on the filter support plate, by sliding elements in grooves, in an oscillating motion relative to the filter support plate to clean the filter plate, or (ii) the filter support plate is guided in the filter chamber by sliding elements such that the filter plate together with the filter support plate is guided in an oscillating motion to clean the filter plate.   
     
     
         2 . (canceled) 
     
     
         3 . The filter system according to  claim 1 , wherein the at least one cleaning chamber is sealed relative to the filter chamber by one or more blocking elements. 
     
     
         4 . The filter system according to  claim 1 , further comprising a cleaning apparatus in the form of a scraper unit. 
     
     
         5 . The filter system according to  claim 1 , wherein the filter plate takes the form of a plate, sheet or mat. 
     
     
         6 . The filter system according to  claim 1 , wherein a conveying screw is provided in the at least one cleaning chamber for discharging a filter cake. 
     
     
         7 . A method for filtering viscous or highly viscous liquids, comprising:
 supplying the viscous or highly viscous liquid to a filter chamber which defines an active filter area in a filter zone, the filter chamber having a filter plate supported by a filter support plate, the filter plate being at least twice as wide as the active filter area, wherein either (i) the filter plate is guided on the filter support plate, by sliding elements in grooves, in an oscillating motion relative to the filter support plate, or (ii) the filter support plate is guided in the filter chamber at the bottom and/or sides by sliding elements such that the filter plate together with the filter support plate is guided in an oscillating motion;   supplying the viscous or highly viscous liquid to the filter chamber through an inlet opening;   carrying away the liquid passing through the filter plate;   moving the filter plate to a cleaning chamber; and   carrying away contaminants present on the filter plate by way of the cleaning chamber.   
     
     
         8 . The method according to  claim 7 , wherein the carrying away of the contaminants present on the filter plate is performed by a back-flushing process initiated by a pressure difference up- and downstream of the filter plate. 
     
     
         9 . The method according to  claim 7 , wherein the carrying away of the contaminants present on the filter plate is performed by a back-flushing process initiated by sealing a back-flushing zone. 
     
     
         10 . The method according to  claim 7 , wherein the carrying away of the contaminants present on the filter plate is performed by using conveying devices. 
     
     
         11 . The method according to  claim 7 , wherein during cleaning of the filter plate, the viscous or highly viscous liquid continues to flow through the filter plate in the filter zone. 
     
     
         12 . The filter system according to  claim 3 , wherein the one or more blocking elements may be moved mechanically, under the control of levers or links, by a reciprocating motion, by springs, by melt pressure, or independently electrically, mechano-pneumatically or hydraulically. 
     
     
         13 . The filter system according to  claim 3 , wherein the one or more blocking elements are formed with an integral valve, by which a filter cake is removable from the cleaning chamber. 
     
     
         14 . The filter system according to  claim 1 , further comprising first and second cleaning chambers arranged on opposite sides of the filter zone, respectively. 
     
     
         15 . The filter system according to  claim 1 , further comprising first and second blocking sliders arranged on opposite sides of the filter zone, respectively. 
     
     
         16 . The filter system according to  claim 1 , further comprising first and second slider elements arranged on opposite sides of the filter support plate, respectively. 
     
     
         17 . The filter system according to  claim 14 , wherein the filter plate and the filter support plate are arranged such that, due to either the oscillating motion of the filter plate relative to the filter support plate or the oscillating motion of the filter plate together with the filter support plate, one portion of the filter plate can be filtering by flowing unfiltered liquid from an unfiltered chamber through the active filter area to a filtered chamber, while another portion of the filter plate is being cleaned in one of the first and second cleaning chambers. 
     
     
         18 . The filtration system according to  claim 1 , wherein the filter plate is selected from the group consisting of a belt, a sheet, a plate or a mat. 
     
     
         19 . The filtration system according to  claim 15 , wherein each of the blocking sliders includes an integral valve. 
     
     
         20 . The filtration system according to  claim 19 , further comprising first and second cleaning chambers arranged on opposite sides of the filter zone, respectively, each cleaning chamber having a discharge duct,
 wherein each of the blocking sliders defines a fluid passage capable of permitting any back-flushed liquid to flow to the discharge duct of one of the cleaning chambers.