Method and apparatus for removing shot from mineral fibre material

Abstract

The invention relates to a method for removing shot from mineral fibres comprising providing a collected web of mineral fibres containing shot, subjecting the collected web of fibres to a disentanglement process, suspending the disentangled fibres in a primary air flow, thereby allowing separation of the fibres from the shot and collecting the fibres, wherein from 0% up to less than 1% by weight binder is present in the fibres collected from the primary air flow.

1 . A method for removing shot from mineral fibres comprising:
 providing a collected web of mineral fibres containing shot;   subjecting the collected web of fibres to a disentanglement process;   suspending the disentangled fibres in a primary air flow, thereby allowing separation of the fibres from the shot; and   collecting the fibres;   wherein from 0% up to less than 1% by weight binder is present in the fibres collected from the primary air flow.   
     
     
         2 . A method according to  claim 1 , wherein from 0% to 0.5% by weight binder is present in the fibres collected from the primary air flow. 
     
     
         3 . A method according to  claim 1 , wherein the disentanglement process comprises feeding the collected web to at least one roller which rotates about its longitudinal axis and has spikes protruding from its circumferential surface. 
     
     
         4 . A method according to  claim 3 , wherein the roller has a diameter based on the outermost points of the spikes from 20 cm to 80 cm, preferably from 30 cm to 70 cm, more preferably from 45 cm to 65 cm and most preferably from 50 cm to 60 cm. 
     
     
         5 . A method according to  claim 3 , wherein the roller rotates at a rate from 500 rpm, preferably from 1000 rpm to 4000 rpm, more preferably from 1500 rpm to 3500 rpm, most preferably from 2000 rpm to 300 rpm. 
     
     
         6 . A method according to  claim 3 , wherein the outermost points of the spikes of the roller move at a speed of from 15 to 200 m/s, preferably from 25 to 150 m/s, more preferably from 40 to 120 m/s, most preferably from 60 to 90 m/s. 
     
     
         7 . A method according to  claim 1 , wherein the method is performed at a mineral wool production line, which feeds a primary or secondary mineral wool web into the fibre disentanglement process. 
     
     
         8 . A method according to  claim 1 , wherein the mineral fibres, when suspended in the primary air flow, are subjected to a further air flow in a different direction to the primary air flow. 
     
     
         9 . A method according to  claim 8 , wherein the primary air flow is generally lateral and the further air flow is generally upwards. 
     
     
         10 . A method according to  claim 1 , wherein the primary air flow had an initial speed of 15 to 200 m/s, preferably from 25 to 150 m/s, more preferably from 40 to 120 m/s, most preferably from 60 to 90 m/s. 
     
     
         11 . A method according to  claim 8 , wherein the further air flow has a speed of from 0.3 to 10 m/s, preferably from 0.5 to 6 m/s, more preferably from 1 to 5 m/s, most preferably from 1 to 3 m/s. 
     
     
         12 . A method according to  claim 1 , wherein the primary air-flow carriers the mineral fibres into a sifting chamber. 
     
     
         13 . A method according to  claim 12 , wherein the fibres are carried in the primary air flow for from 0.5 to 5 metres, preferably from 0.7 to 3 metres, more preferably from 1 to 2 metres before reaching the sifting chamber. 
     
     
         14 . A method according to  claim 8 , wherein the mineral fibres travel for from 0.5 to 5 metres, preferably from 0.7 to 3 metres, more preferably from 1 to 2 metres in the primary air flow before meeting the further air flow. 
     
     
         15 . An apparatus for removing shot from mineral fibres comprising a disentanglement apparatus for disentangling a web of mineral fibres to provide disentangled fibres,
 web supply means for supplying the web to the disentanglement apparatus,   air flow supply means for supplying a primary air flow in which to suspend disentanglement mineral fibres,   a sifting chamber into which the fibres are carried in the primary air-flow and in which shot separates from the fibres,   a discharge outlet at the lower end of the sifting chamber for collecting shot separated from the mineral fibres, and   a collector for collecting the disentangled mineral fibres,   wherein the disentanglement apparatus and the sifting chamber are separated by a lateral distance of at least 0.5 metres, preferably from 0.7 to 5 metres, more preferably from 1 to 3 metres.   
     
     
         16 . An apparatus according to  claim 15 , wherein further air flow supply means are positioned at the lower end of the sifting chamber. 
     
     
         17 . An apparatus according to  claim 15 , wherein the sifting chamber has a volume of from 5 m 3  to 20 m 3 , preferably from 7 m 3  to 15 m 3 , more preferably from 8 m 3  to 12 m 3 . 
     
     
         18 . An apparatus according to  claim 16 , wherein there are at least two further air flow supply means.