Dryer for particulate material

Claim 2

A dryer for particulate material comprising, in combination: a drying chamber through which particulate material flows by gravity; first air lock means for admitting particulate material to the upper end of said drying chamber; second air lock means for removing particulate material from the lower end of the drying chamber; a thermal pump system including a compressor having a low pressure side and a high pressure side, radiator means in the drying chamber which is directly contacted by said particulate material as it passes through said chamber, said radiator means having an inlet and an outlet, a condenser, a hot fluid conduit connecting the high pressure side of the compressor to the radiator inlet, a cool fluid conduit connecting the radiator outlet to the condenser, and a fluid return conduit from the condenser to the low pressure side of the compressor; a closed duct system which includes the drying chamber, and blower means in the duct system to circulate gas through said drying chamber in countercurrent to the flow of particulate material so as to absorb moisture vaporized from the material; means for heating said gas in the duct system before it enters the drying chamber, the condenser of the thermal pump system being positioned in the duct system upstream from the heating means where it condenses moisture from the gas which has left the drying chamber; and condensate discharge means for removing condensed moisture from the duct system.

Claim 3

The dryer of claim 1 in which the radiator means comprises a plurality of vertically spaced tiers of generally horizontal pipes so that the particulate material flows over said tiers of pipes, and risers connecting said tiers of pipes.

Claim 4

The dryer of claim 2 in which the pipes in successive tiers are staggered, and inverted V-shaped heat exchange fins on said pipes are positioned to cause serpentine flow of particulate material.

Claim 5

The dryer of claim 2 in which the radiator inlet is connected to the pipes in the lowermost tier and the radiator outlet is connected to the pipes in the uppermost tier.

Claim 6

The dryer of claim 1 which includes an internal combustion engine for driving the compressor, and in which the means for heating gas in the duct system includes a heat exchanger provided with pipes for the engine exhaust gases.

Claim 7

The dryer of claim 5 in which the internal combustion engine is provided with cooling means which is located in the duct system immediately downstream from the condenser and upstream from the heat exchanger.

Claim 8

The dryer of claim 6 in which the cooling means comprises a liquid cooling system which has a radiator located in the duct system.

Claim 9

The dryer of claim 5 in which the internal combustion engine is in a closed compartment, and a combustion air inlet pipe and an exhaust gas outlet pipe connect said engine to the ambient atmosphere.

Claim 10

The dryer of claim 1 which includes a closed compartment in heat exchange relationship with the duct system downstream from the condenser, an internal combustion engine in said compartment for driving the compressor, a combustion air inlet pipe connecting the engine with the ambient atmosphere, a heat exchanger in the duct system provided with pipes for the engine exhaust gases, said pipes discharging to the ambient atmosphere, and cooling means for the engine which is located in the duct system immediately downstream from the condenser and upstream from the heat exchanger.

Claim 11

The drying of claim 9 in which the cooling means comprises a liquid cooling system which has a radiator located in the duct system.

Claim 12

A dryer for particulate material comprising, in combination: a drying chamber through which particulate material flows by gravity; first air lock means for admitting particulate material to the upper end of said drying chamber; second air lock means for removing particulate material from the lower end of the drying chamber; radiator means in the drying chamber; means including a pump for circulating hot fluid through said radiator means; a closed duct system which includes the drying chamber, and blower means in the duct system to circulate gas through said drying chamber in countercurrent to the flow of particulate material so as to absorb moisture vaporized from the material; an internal combustion engine for driving the pump, said engine being in heat exchange relationship to the duct system; heat insulating means enclosing said internal combustion engine to reduce radiation of engine heat to the ambient atmosphere; a combustion air inlet pipe and exhaust gas outlet means connecting said engine to the ambient atmosphere, said exhaust gas outlet means passing through the closed duct system downstream from the blower means; a heat exchanger in the duct system adjacent the engine, said heat exchanger including the exhaust gas outlet means; cooling means for the engine which is located in the duct system adjacent the blower means; a condenser which is located in the duct system immediately upstream from the engine cooling means where it condenses moisture from the gas which has left the drying chamber; and condensate discharge means for removing condensed moisture from the duct system.

Claim 13

A dryer for particulate material comprising, in combination: a drying chamber through which particulate material flows by gravity; first air lock means for admitting particulate material to the upper end of said drying chamber; second air lock means for removing particulate material from the lower end of the drying chamber; radiator means in the drying chamber; means including a pump for circulating hot fluid through said radiator means; a closed duct system which includes the drying chamber, and blower means in the duct system to circulate gas through said drying chamber in countercurrent to the flow of particulate material so as to absorb moisture vaporized from the material; an internal combustion engine for driving the pump, said engine being in heat exchange relationship to the duct system; heat insulating means enclosing said internal combustion engine to reduce radiation of engine heat to the ambient atmosphere; a combustion air inlet pipe and exhaust gas outlet means connecting said engine to the ambient atmosphere, said exhaust gas outlet means passing through the closed duct system downstream from the blower means; a heat exchanger in the duct system adjacent the engine, said heat exchanger including the exhaust gas outlet means; cooling means for the engine which is located in the duct system adjacent the blower means; a condenser which is located in the duct system immediately upstream from the engine cooling means where it condenses moisture from the gas which has left the drying chamber; and condensate discharge means for removing condensed moisture from the duct system.

Claim 14

The dryer of claim 11 in which the radiator means in the drying chamber comprises vertically spaced tiers of generally horizontal heat exchange pipes which are provided with inverted V-shaped heat radiating fins, and the pipes in adjacent tiers are staggered to cause serpentine flow of material through said chamber.

Claim 15

The dryer of claim 11 in which the cooling means for the engine comprises a liquid cooling system which has a radiator located in the duct system.