Claims
- 1. In a dryer for reducing the moisture content of material in sheet form comprising an elongated generally horizontal stationary housing having material entrance and discharge ends, a continuous conveyor extending through said housing which includes a material drying chamber intermediate its ends and through which said conveyor extends, means externally of said drying chamber for recirculating gas lengthwise through said drying chamber in the direction in which the material is conveyed through said drying chamber and maintaining a gas pressure less than atmospheric in the material exit end of said chamber, means for heating the gas, a supplemental gas chamber at the material exit end of said drying chamber, means restricting entrance of air into the material exit end of said supplemental chamber, power actuated means connected to said supplemental chamber for exhausting gas therefrom, and means responsive to a condition in the dryer at the material feed end of said drying chamber for controlling the amount of gas exhausted from said supplemental chamber whereby a predetermined condition is maintainabIe in the dryer at the material feed end of said drying chamber and the gas pressure in said supplemental chamber may be maintained at a pressure less than that of the subatmospheric gas pressure in the material exit end of said drying chamber.
- 2. In a dryer for reducing the moisture content of material in sheet form comprising an elongated generally horizontal stationary housing having material entrance and discharge ends, a continuous conveyor extending through said housing which includes a material drying chamber intermediate its ends and through which said conveyor extends, means externally of said drying chamber for recirculating gas lengthwise through said drying chamber in the direction in which the material is conveyed through said drying chamber and maintaining a gas pressure less than atmospheric in the material exit end of said chamber, means for heating the gas, a first supplemental gas chamber at the material feed end of said drying chamber, a second supplemental gas chamber at the material exit end of said drying chamber, means restricting entrance of air into the material exit end of said second chamber, power actuated means connected to said second chamber for exhausting gas therefrom, and means in said first supplemental chamber responsive to a condition therein for controlling the amount of gas exhausted from said second supplemental chamber by said power actuated exhaust means thereof whereby a predetermined condition is maintainable in said first supplemental chamber and the gas pressure in said second supplemental chamber is maintainable at a pressure less than the subatmospheric gas pressure in the material exit end of said drying chamber.
- 3. In a dryer for reducing the moisture content in sheet form comprising an elongated generally horizontal stationary housing having material entrance and discharge ends, a continuous conveyor extending through said housing for conveying material to be processed through the housing which includes a material drying chamber intermediate its ends and through which the conveyor extends, means externally of the drying chamber for recirculating gas lengthwise through said drying chamber in the direction in which the material is conveyed therethrough and maintaining a gas pressure less than atmospheric in the material exit end of said drying chamber, means for heating the gas, a first supplemental gas chamber at the material feed end of said drying chamber, means adjacent to the material feed end of said first supplemental chamber for controlling flow of air into said first supplemental chamber, a second supplemental gas chamber at the material exit of said drying chambers, means restricting entrance of air into the material exit end of said second supplemental chamber, an exhaust fan connected to said second supplemental chamber, means in said first supplemental chamber for sensing a condition therein and for controlling the amount of gas exhausted from said second supplemental chamber by said exhaust fan whereby a predetermined condition is maintainable in said first supplemental chamber and a gas pressure in said second supplemental chamber is maintainable less than that of the subatmospheric gas pressure in the material exit end of said drying chamber.
- 4. In a dryer for reducing the moisture content of material in sheet form comprising an elongated generally horizontal stationary housing having material entrance and discharge ends, a continuous conveyor extending through said housing which includes a material drying chamber intermediate its ends and through which said conveyor extends, means externally of said drying chamber for recirculating gas lengthwise through said drying chamber in the direction in which the material is conveyed through said drying chamber and maintaining a gas pressure less than atmospheric in the material exit end of said chamber, means for heating the gas, a supplemental gas chamber at the material exit end of said drying chamber, means restricting entrance of air into the material exit end of said supplemental chamber, power actuated means connected to said supplemental chamber for exhausting gas from said supplemental chamber, and means including a temperature instrumentality up stream from said drying chamber for controlling the amount of gas exhausted from said supplemental chamber by said power actuated exhaust means whereby a predetermined temperature may be maintained in the dryer up stream from said drying chamber and the gas pressure in said supplemental chamber may be maintained at a pressure less than that of the subatmospheric gas pressure in the material exit end of said drying chamber.
- 5. In a dryer for reducing the moisture content of material in sheet form comprising a horizontal stationary housing having material entrance and discharge ends, a continuous conveyor extending through the housing for conveying material to be processed through said housing which includes a material drying chamber intermediate its ends and through which said conveyor extends, means externally of said drying chamber for recirculating gas lengthwise therethrough in the direction in which the material is conveyed through said drying chamber and maintaining a gas pressure less than atmospheric in the material exit end of said drying chamber, means for heating the gas, a first supplemental gas chamber adjacent to the material feed end of said drying chamber, a second supplemental gas chamber at the material exit end of said drying chamber, means restricting entrance of air into the material exit end of said second supplemental chamber, an exhaust fan connected to said second supplemental chamber, a temperature responsive instrumentality in said first supplemental chamber for controlling the amount of gas discharged from said second supplemental chamber by said exhaust fan whereby a predetermined temperature may be maintained in said first supplemental chamber and the gas pressure in said second supplemental chamber may be maintained less pressure than that of the subatmospheric gas pressure in the material exit end of said drying chamber.
- 6. In a dryer for reducing the moisture content of material in sheet form comprising a horizontal stationary housing having material entrance and discharge ends, a continuous conveyor extending through the housing for conveying material to be processed through said housing which includes a material drying chamber intermediate its ends and through which said conveyor extends, means externally of said drying chamber for recirculating gas lengthwise therethrough in the direction in which the material is conveyed through said drying chamber and maintaining a gas pressure less than atmospheric in the material exit end of said drying chamber, means for heating the gas, a first supplemental gas chamber adjacent to the material feed end of said drying chamber, means adjacent to the feed end of said first supplemental chamber for controlling the entrance of air thereinto, a second seupplemental gas chamber at the material exit end of said drying chamber, means restricting entrance of air into the material exit end of said second supplemental chamber, an exhaust fan connected to said second supplemental chamber, means including a thermocouple in said first supplemental chamber for controlling the amount of gas discharged from said second supplemental chamber by said exhaust fan whereby a predetermined temperature may be maintained in said first supplemental chamber and the gas pressure in said second supplemental chamber may be maintained less than that of the subatmospheric gas pressure in the material exit end of said drying chamber.
- 7. In apparatus for reducing the moisture content of material in sheet form comprising an elongated generally horizontal stationary housing having material entrance and discharge ends, a continuous conveyor extending through said housing for conveying material to be processed through said housing which includes a material drying chamber intermediate its ends and through which the conveyor extends, means externally of the drying chamber for recirculating gas lengthwise through said drying chamber in the direction in which the material is conveyed through said drying chamber and maintaining a gas pressure less than atmospheric in the material exit end of said drying chamber, means for heating the gas, a first gas supplemental chamber including a vent stack adjacent to the material feed end of said drying chamber, a second gas supplemental chamber at the material exit of said drying chamber, said conveyor having pinch rolls at least at the material exit end of said second supplemental chamber, means adjacent to said pinch rolls at the material exit end of said second supplemental chamber for restricting entrance of air into the material exit ends of said second supplemental chamber, a power driven exhaust fan connected to said second supplemental chamber, means including a control instrumentality in said stack of said first supplemental chamber and responsive to a condition therein for controlling the amount of gas discharged from said second supplemental chamber by said exhaust fan whereby a predetermined condition is maintainable in said first supplemental chamber exhaust stack and the gas pressure in said second supplemental chamber may be maintained less than the subatmospheric gas pressure in the exit end of said drying chamber.
- 8. A method of drying material which comprises providing a drying chamber with product feed and exit ends, means for circulating a gas through the drying chamber from the feed end to the exit end and returning a portion of the gas from the exit end to the feed end for recirculating through the drying chamber, heating the gas in its return from the exit end of the drying chamber to the feed end thereof, providing a supplemental gas chamber at the exit end of the drying chamber having means for restricting the entrance of air at ambient temperature thereinto through the material exit end thereof, sensing a condition at the material feed end of the drying chamber and thereby controlling the exhaust of gas from the supplemental chamber at the material exit end of the drying chamber to maintain a predetermined condition at the material feed end of the drying chamber and a gas pressure in said supplemental chamber less than atmospheric pressure and less than the subatmospheric gas pressure in the material exit end of the drying chamber such that the primary exhaust of gas and moisture from the drying chamber is through said supplemental chamber.
- 9. A method of drying material which comprises providing a drying chamber with product feed and exit ends, means for circulating a gas through the drying chamber from the feed end to the exit end and returning a portion of the gas from the exit end to the feed end for recirculating through the drying chamber, heating the gas in its return from the exit end of the drying chamber to the feed end thereof, providing a supplemental gas chamber at the feed end of the drying chamber, providing a supplemental gas chamber at the exit end of the drying chamber having means for restricting the entrance of air at ambient temperature thereinto through the material exit end thereof, sensing a condition at the material feed end of the drying chamber and thereby controlling the exhaust of gas from the supplemental chamber at the material exit end of the drying chamber to maintain a predetermined condition at the material feed end of the drying chamber and a gas pressure in the supplemental chamber at the exit end of the drying chamber less than the subatmospheric gas pressure in the material exit end of the drying chamber such that the primary exhaust of gas and moisture from the drying chamber is through said supplemental chamber at the exit end of the drying chamber.
- 10. A method of drying material which comprises providing a drying chamber with product feed and exit ends, means for circulating a gas through the drying chamber from the feed end to the exit end and returning a portion of the gas from the exit end to the feed end for recirculating through the drying chamber, heating the gas in its return from the exit end of the drying chamber to the feed end thereof, providing a supplemental gas chamber at the feed end of the drying chamber having means at the material feed end thereof for controlling the flow of gas therethrough, providing a supplemental gas chamber at the exit end of the drying chamber having means for restricting the entrance of air at ambient temperature thereinto through the material exit end thereof, sensing a condition of the gas in the supplemental chamber at the material feed end of the drying chamber and thereby controlling the exhaust of gas from the supplemental chamber at the material exit end of the drying chamber to maintain a predetermined condition in the supplemental chamber at the material feed end of said drying chamber and a gas pressure in the supplemental chamber at the material exit end of said drying chamber less than the subatmospheric gas pressure in the material exit end of the drying chamber such that the primary exhaust of gas and moisture from the drying chamber is through said supplemental chamber at the material exit end of said drying chamber.
- 11. The method of drying material as defined in claim 10 wherein the temperature in the supplemental chamber at the material feed end of the drying chamber is sensed and the volume of gas exhausted from the supplemental chamber at the material exit end of the drying chamber is controlled in response thereto to maintain a temperature in the supplemental chamber at the material feed end of the drying chamber slightly above ambient temperature.
CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of co-pending application Ser. No. 231,274 filed Feb. 4, 1981 now abandoned.
US Referenced Citations (4)
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
231274 |
Feb 1981 |
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