Jet tube dryer with independently controllable modules

A method of drying a product supported within and fed through a drying apparatus, comprising the steps of:

• supporting the product on at least one conveyor for transport through the apparatus;
• circulating gas at a gas-flow rate within each of a plurality of drying zones;
• directing the gas within each drying zone through a plurality of tubes toward the at least one conveyor to cause the gas to impinge upon the product, thereby tending to dry the product;
• independently controlling, in each of the drying zones, circulation of gas that is to impinge upon the product, including causing a gas-flow rate at the product in at least one of the drying zones to be higher than a gas-flow rate at the product in at least one other of the drying zones, thereby tending to dry the product in said at least one zone faster than the product in said at least one other zone;
• and
• feeding the product on the at least one conveyor through each of the plurality of drying zones.

A jet tube forest having upper and lower sections disposed on opposite sides of a conveyor that feeds a product through a tubular drying apparatus, comprising:

• an upper forest section comprising a plurality of longitudinally spaced rows, each row comprising a plurality of transversely spaced tubes, wherein the tubes in each row are transversely spaced from the tubes in any immediately longitudinally adjacent row;
• and
• a lower forest section comprising a plurality of longitudinally spaced rows, each lower forest section row comprising a plurality of transversely spaced tubes, wherein the tubes in each lower forest section row are transversely spaced from the tubes in any immediately longitudinally adjacent lower forest section row;
• the upper forest section rows being longitudinally spaced from the lower forest section rows.

An apparatus for drying a product, comprising:

• means for supporting the product within the apparatus and transporting it therethrough;
• means for defining a plurality of zones that receive the product as the product is fed through the apparatus;
• tube means disposed adjacent the supporting means for directing gas to impinge upon the product to tend to dry the product;
• and
• means for circulating gas that is to impinge upon the product at a variable gas flow rate at the product in at least one of the zones and for circulating gas that is to impinge upon the product at a higher variable gas-flow rate at the product in at least one other of the zones, thereby tending to dry the product in said at least one zone faster than the product in said at least one other zone.

A drying apparatus for drying a product fed therethrough, comprising:

• at least one conveyor supporting the product within the drying apparatus for transport therethrough;
• at least one dryer zone, comprising:
• a plurality of tubes disposed adjacent to the at least one conveyor, the tubes directing gas to impinge upon the product to tend to dry the product;
• and
• at least one circulation fan causing the gas to circulate at a gas-flow rate through the zone to the tubes;
• at least one filter that receives gas flowing from the product and collects fibrous material flowing from the product;
• a differential pressure sensor for sensing gas pressure on opposite sides of the at least one filter and for issuing a signal indicating when filter cleaning is necessary;
• and
• a brush that sweeps across the at least one filter in response to the signal to disengage fibrous material accumulated in the at least one filter.