Drawbox air shut-off and method for doffing a textile comber

In a textile comber which includes a drawbox having a pair of coiler units each having a drafting element, a calender, a coiler with a coiler tube, and vacuum cleaning nozzles for removing waste and other air borne matter from said coiler units in said drawbox, suction lines connected to said vacuum cleaning nozzles for removal of said waste and air borne matter, combed sliver produced by said textile comber being fed by said coiling units to said coiler tube for deposit in delivery cans positioned below said coiler units, apparatus for shutting off the air suction in said drawbox during doffing of said delivery cans to facilitate reliable entry of said sliver into said coiler tube and coiler comprising:

• shut off duct assemblies in said suction lines downstream of said vacuum cleaning nozzles;
• a closure valve carried in said shut-off duct assemblies for shutting off the flow of suction air through said vacuum cleaning nozzles and said suction lines;
• and
• control means responsive to a prescribed quantity of sliver being deposited in said coiler can for moving said closure valves in a closed position for shutting off said air suction and maintaining said closure valves in said closed position for a prescribed period of time following doffing of said delivery cans during restart of said comber until sliver has been properly reintroduced into said coiler tube and cans.

A method of controlling the suction air to the drawbox of a textile comber during doffing, said comber being of a type which includes a coiling unit disposed within a drawbox enclosure which receives combed sliver and deposits said sliver in a delivery can below said coiling unit, and suction air is delivered to said drawbox enclosure for removing waste and other air borne matter from said drawbox enclosure adjacent said coiling unit, wherein said method includes controlling said suction air to facilitate entry of sliver into an empty leveling can which comprises:

• stopping said comber when a prescribed amount of sliver has been deposited in said delivery can;
• stopping the supply of suction air to said drawbox enclosure generally simultaneously with stopping said comber;
• doffing said full delivery can by replacement with an empty delivery can;
• restarting said comber;
• maintaining said supply of suction air to said drawbox enclosure shut-off during restart of said comber;
• and
• resuming said supply of suction to said drawbox enclosure upon said comber reaching operational speed for a period of time in a manner that air interference with sliver delivery caused by excessive suction air is prevented during reentry of said sliver into said coil tube and delivery can.