Tunnel kiln

Claim 2

A continuous tunnel kiln firing section comprising: an elongated housing through which stacks of ware to be fired may be moved; said housing comprising vertical sides, a horizontal roof connecting said sides, and means between the lower ends of the sides forming the base of said housing, said base means including means for continuously transporting the stacks of ware through said housing, a plurality of excess-air burners spaced along each side of said housing for generating high volume swiftly moving streams of hot gases; a plurality of inlet ducts spaced longitudinally along the lower portion of each side of said housing and connected with said burners for directing the streams of hot gases from said burners upward in lateral non-longitudinal flow adjacent the inner walls of said sides; a plurality of exhaust ducts spaced longitudinally along the lower portion of each side of said housing for exhausting excess gases from the housing; said inlet and exhaust ducts being spaced relative to each other such that said hot gases circulate laterally over along the roof of said housing, laterally downward and through the stacks of ware to be fired, and are drawn upward again in substantially the same lateral flow path with the swiftly moving streams of hot gases from said burners to form a powerful lateral recirculating current of hot gases which provides substantially uniform temperatures on a given lateral plane throughout the stacks of ware to be fired.

Claim 3

The tunnel kiln firing section of claim 1 wherein said excess-air burners further comprise means for adjusting the flow of said streams of hot gases to control the volume and velocity of such flow.

Claim 4

The tunnel kiln firing section of claim 1 further comprising means for adjusting the air/fuel ratio of said excess-air burners to control the temperature of said swiftly moving streams of hot gases on a given lateral plane in said stacks.

Claim 5

The tunnel kiln firing section of claim 3 further comprising means for operating said excess-air burners at a ratio of about 20 parts air to 1 part fuel.

Claim 6

The tunnel kiln firing section of claim 1 wherein said excess-air burners are spaced along the lower portion of each side of said housing and said ducts direct the hot gases from said burners upward through elongated slot orifices spaced adjacent the lower portion of said side to create a substantially continuous sheet of hot gases moving upward adjacent the inner wall of said side, said burners providing a controlled temperature gradient with uniform lateral temperature planes and variable longitudinal temperature planes.

Claim 7

The tunnel kiln firing section of claim 5 wherein each of said orifices is provided with an adjustable damper for controlling the width of said orifice so as to control the velocity of the hot gases streaming through said orifice.

Claim 8

The tunnel kiln firing section of claim 1 further comprising means for controlling the velocity of said hot gases in the range from 2500 to 3000 feet per minute.

Claim 9

The tunnel kiln firing section of claim 1 further comprising means for controlling the temperature of said hot gases in the range from 2400° to 2600° F.

Claim 10

The tunnel kiln firing section of claim 5 further comprising a plurality of exhaust ports spaced along the lower portion of said side of said housing between said orifices, and further comprising an exhaust manifold connecting said exhaust ports for withdrawing hot gases from said tunnel kiln firing section.

Claim 11

The tunnel kiln firing section of claim 9 wherein each of said exhaust ports is provided with an adjustable damper for controlling the volume of hot gases withdrawn from said tunnel kiln firing section.

Claim 12

The tunnel kiln firing section of claim 5 further comprising a plurality of temperature measuring means spaced along the upper portion of said side of said housing for measuring the temperature of the swiftly moving sheet of hot gases.

Claim 13

The tunnel kiln firing section of claim 1 further comprising a plurality of deflectors projecting from the roof of said housing and extending parallel to the axis thereof for deflecting the current of hot gases downward and through the stacks of ware to be fired.

Claim 14

The tunnel kiln firing section of claim 9 wherein said burners and said orifices and said exhaust ports are spaced along both sides of said housing and said hot gases circulate up the side walls of said housing, over along the roof of said housing and downward at the center of said housing to form powerful recirculating currents rotating in opposite directions in opposite sides of said tunnel kiln firing section.

Claim 15

In association with a continuous tunnel kiln firing section, a tunnel kiln preheat section comprising: an elongated housing through which stacks of ware to be preheated may be moved: said housing comprising vertical sides, a horizontal roof connecting said sides, and means between the lower ends of the sides forming the base of said housing, said base means including means for continuously transporting the stacks of ware through said housing, means feeding exhaust gases from the tunnel kiln firing section to each side of said housing for generating high volume swiftly moving streams of hot gases; and a plurality of inlet ducts spaced longitudinally along the lower portion of each side of said housing and connected with said exhaust gas feed means for directing the streams of hot gases from said firing section upward in lateral non-longitudinal flow adjacent the side wall of said housing; a plurality of exhaust ducts spaced longitudinally along the lower portion of each side of said housing for exhausting excess gases from the housing; said inlet and exhaust ducts being spaced relative to each other such that said hot gases circulate laterally upwardly along the roof of ware to be preheated, and are drawn upward again in substantially the same lateral flow path with the swiftly moving streams of hot gases from said firing section to form a powerful lateral recirculating current of hot gases which provides substantially uniform temperatures in given lateral planes throughout the stacks of ware to be preheated.

Claim 16

In association with a continuous tunnel kiln firing section, a tunnel kiln preheat section comprising: an elongated housing through which stacks of ware to be preheated may be moved: said housing comprising vertical sides, a horizontal roof connecting said sides, and means between the lower ends of the sides forming the base of said housing, said base means including means for continuously transporting the stacks of ware through said housing, means feeding exhaust gases from the tunnel kiln firing section to each side of said housing for generating high volume swiftly moving streams of hot gases; and a plurality of inlet ducts spaced longitudinally along the lower portion of each side of said housing and connected with said exhaust gas feed means for directing the streams of hot gases from said firing section upward in lateral non-longitudinal flow adjacent the side wall of said housing; a plurality of exhaust ducts spaced longitudinally along the lower portion of each side of said housing for exhausting excess gases from the housing; said inlet and exhaust ducts being spaced relative to each other such that said hot gases circulate laterally upwardly along the roof of ware to be preheated, and are drawn upward again in substantially the same lateral flow path with the swiftly moving streams of hot gases from said firing section to form a powerful lateral recirculating current of hot gases which provides substantially uniform temperatures in given lateral planes throughout the stacks of ware to be preheated.

Claim 17

The tunnel kiln preheat section of claim 14 further comprising blower means mounted to said housing for drawing the exhaust gases from the firing section and forcing such gases through said ducts.

Claim 18

The tunnel kiln preheat section of claim 15 further comprising a booster burner mounted to said housing for adding heat to said streams of hot gases.