Abstract A method of drying a product utilizing a combustible fuel employs combustion gases as the medium for conveying the product through the dryer. The combustible fuel is burned in a combustion zone to produce heat and gases of combustion. The heat and gases are moved from one end of a drying zone to the opposite end along with the product being dried, which is pneumatically conveyed. A portion of the combustion gases are then separated from the dried product and directed along a path, which bypasses the combustion zone, to reintroduce the gases into the forward end of the drying zone. By recycling the combustion gases for use as the conveying medium, while bypassing the combustion zone, the oxygen content is reduced in the drying zone without affecting combustion in the combustion zone. Thus there is less likelihood of thermal decomposition occurring in the drying zone. The recycling of the combustion gases which have a relatively high vapor content also increases the vapor pressure of the liquid water droplets in the drying zone. These droplets may therefore remain near the surface of the product being dried for a longer period of time and act as a barrier against thermal decomposition. The relatively high K value of the water droplets also facilitates heat transfer to the interior of the product thereby forcing additional moisture toward the surface.
Inventors
👤 S Thompson
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-30 18:59
CPC Classifications
F; F26; F26B; F26B17/00; F26B17/10; F26B17/106
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
164 words
A method of drying a product comprising the steps of: burning a combustible fuel in a combustion zone to produce heat and gases of combustion; moving the heat and gases of combustion through a longitudinally extending drying zone disposed on one side of the combustion zone; pneumatically conveying the product from one end of the drying zone which is nearest the combustion zone to the opposite end of the drying zone without passing the product through the combustion zone; separating at least a portion of the gases of combustion from the product after the latter passes from the drying zone; directing the separated portion of the combustion gases along a path independent of the drying zone and toward said one end of the drying zone; bypassing the combustion zone with said separated portion of gases; and introducing said sepaRated portion of gases into the drying zone at said one end whereby said separated portion of gases comprises a portion of the pneumatic conveying medium.
Claim 2
Independent Claim
164 words
A method of drying a product comprising the steps of: burning a combustible fuel in a combustion zone to produce heat and gases of combustion; moving the heat and gases of combustion through a longitudinally extending drying zone disposed on one side of the combustion zone; pneumatically conveying the product from one end of the drying zone which is nearest the combustion zone to the opposite end of the drying zone without passing the product through the combustion zone; separating at least a portion of the gases of combustion from the product after the latter passes from the drying zone; directing the separated portion of the combustion gases along a path independent of the drying zone and toward said one end of the drying zone; bypassing the combustion zone with said separated portion of gases; and introducing said sepaRated portion of gases into the drying zone at said one end whereby said separated portion of gases comprises a portion of the pneumatic conveying medium.
Claim 3
Dependent Claim
37 words
A method as set forth in claim 1, wherein is included the step of varying the flow of gases directed along said path in accordance with the quantity of said product being conveyed through the drying zone.
Claim 4
Dependent Claim
28 words
A method as set forth in claim 1, wherein is included the step of spraying water onto said product prior to conveying the product through the drying zone.
Claim 5
Dependent Claim
45 words
A method as set forth in claim 1, wherein is included subsequent to said separating step the step of advancing any remaining portion of the gases together with the dried product to a separating zone for complete separation of the product from the conveying medium.