Machines for drying sheets of paper or like material

Claim 2

A machine for drying sheets of paper coated with varnish or the like the invention comprising a perforated endless conveyor to receive the sheet material, an upper chamber to which high pressure air is supplied, a perforated bottom for said upper chamber, and a lower chamber forming a vacuum chamber, a perforated top for said vacuum chamber between which chambers the conveyor passes, the air passing from the upper chamber and through the conveyor to the lower chamber, the vacuum therein maintaining the sheet in contact with the surface of the conveyor, and said conveyor comprising perforated trays and endless chains on which the trays are mounted and which form a seal for the sides of the trays.

Claim 3

The machine defined in claim 1, wherein said conveyor has a generally horizontally moving air pervious upper flight, and longitudinally spaced hot air and cool air drying means disposed along said flight to act in succession on said sheets, said hot air drying means comprising means supplying high pressure hot air to said upper chamber, and said cool air drying means being located to receive said sheets after they have been subjected to hot air drying and comprising means defining a high pressure cool air chamber above the flight and discharging cool air toward the flight and means defining a reduced pressure cool air chamber below the flight adapted to receive cool drying air after passage through the flight and direct it toward an exhaust.

Claim 4

A machine for drying sheets of paper as in claim 2 in which a blanket or overlay of porous fireproof material covers the conveyor flight.

Claim 5

The machine defined in claim 2, wherein means is provided whereby some of the hot drying air from said vacuum chamber is reheated and recirculated into said upper hot air chamber.

Claim 6

The machine defined in claim 2, wherein a blower fan assembly is provided in the hot air drying means with its intake connected to receive some of the still warm drying air from said lower chamber and its outlet connected to discharge air back into said upper chamber.

Claim 7

The machine defined in claim 2, wherein said conveyor flight is driven at a speed of about 300-500 feet per minute, and said air in the upper chamber of the hot air drying means has a temperature of about 550* to 600* F. 7. The machine defined in claim 6 wherein said cooling air is substantially at ambient temperature.

Claim 8

A machine for drying sheets of paper as in claim 2 having an air jet at the cool drying air end of the conveyor to lift the leading end of the sheet therefrom.