UNITHERM’S air heating system is designed specifically for mass Industrial batch drying of pulses.It’s superior design, efficient performance and high fuel economy makes it a better buy than any other heater-drier of its kind to achieve much lower drying costs.

The unit is easy to install, simple to maintain and highly economical to operate.

The design is suitable for a maximum temperature of clean hot air at 900 C.

Principle:

Convection Drying :
In convective drying the heat required for evaporating moisture from the drying product is supplied by the external drying medium, i.e. hot air which  comes in direct contact with wet pulses & is used to supply heat and carry away the vapourised moisture. The heat is transferred to the wet solid mainly by convection

Heated Air Drying:
In heated air drying air is heated to the desired temperature, using a direct fired Hot Air Generator.

Since the drying involves both heat and mass transfer operations simultaneously, the entire system has been properly designed, taking into consideration a large amount of factors like, optimum air temperature suitable for drying, air flow rate, air pressure, air velocity required, total perforated area available for air flow, total weight of the pulses to be dried, initial & final moisture contents, dimensions of the bin, height of the stacked pulses, etc.

The drying system mainly consist of

1. Static flat bed batch dryers
2. Hot Air Generator.
3. Blower and Controls
4. Air distribution system

Construction:
Static flat bed batch dryers: As the name suggests, the pulses are kept static in a Bin of the desired capacity ranging from 2 to 6 Tons. In the flat bed batch type dryer surface area of dryer is more and depth of drying layer is less. Grains are spread 0.6 to 1.2 m deep over the perforated floor and dried. 

The main advantages are:-

1. The whole batch is dried quickly.
2. There is less likehood of over drying.
3. Lower air pressure is required to force the drying air.

The Hot Air Generator is Oil or wood/ solid fuel fired medium air temperature hot air generator, which is very compact in construction of vertical design, with External bottom furnace.

The main constituents of oil fired hot air generator are the M.S. inner & outer casings (inner S.S. casing optional) which also act as the combustion chamber. The main body of the Generator is of sturdy Construction made out of heavy gauge steel and Structure. The body is painted with epoxy paint to combat corrosive industrial atmosphere.

A special, anti drip design, high efficiency, imported burner of Riello (Italy) make with low noise blower and fuel oil pump ensure almost smokeless and silent operation and reduces the downtime and maintenance problems greatly. Due to it’s unique design & efficient mixing of air & fuel, the combustion efficiency & hence the efficiency of the hot air generator is also increased.
The connected load is also much lower compared to any indigenous burner resulting in sizeable power savings.The Safety controls and instrumentation provided ensure completely safe operation and provide Audio Visual alarm and cuts off the ignition system is case of abnormal operating conditions.

Forced Draught Blower
Suitably designed for heating the cold air in the hot air generator & force circulating the hot air through the bed of pulses.

Low Operating Cost:
The rising prices of the fuel oil have made the use of oil as a heating medium prohibitively costly. In these times of highly competitive markets, it has become necessary to design the most fuel efficient system.The UNITHERM oil fired Hot Air Generator is designed for highest efficiency, by virtue of which, it produces heat at extremely low cost.

Trouble – Free Operation:
The Unit is of Sturdy construction and also there are very few moving parts; this ensures long life & trouble free operation of the unit.

Clean (Uncontaminated) Hot Air can be obtained without any intermediate medium such as steam, water or oil and hence cost oriented problems such as low heat transfer efficiency, costly piping, water treatment, Boiler attendant, Indian Boiler Regulations, etc, can be done away with by installing Unitherm’ oil fired Hot Air Generators which have the following salient features.

Salient Features:

1. Clean, Uncontaminated Hot Air available Economically.
2. Hot Air available at temperature up to 700 C.
3. Multiple passes on air side ensure high thermal efficiency.
4. Lowest operating costs, compared to Electricity, Steam & thermic oil heating.
5. Vertical design, requires very low floor space.
6. Outside the purview of I.B.R.
7. Sturdy and simple construction.
8. Trouble free operation.
9. Can be connected to existing or new dries without any modifications.
10. Low motive power requirements
11. Quick after sales service available.