Products Range
Process Heating > Direct Fired Hot Air Generators
  • HAG SERIES Oil / LPG/Natural gas fired 50,000 to 10 Lac Kcal/hr
  • HAG C SERIES Coal / wood / multi fuel design 50,000 to 6lac Kcal/hr
1) Multi -pass, UNIQUE SHELL & TUBE DESIGN, Solid fuel fired Hot Air Generators


UNITHERM'S solid fuel fired air heating system is designed specifically with large Industrial drying in mind.

It's superior design, efficient performance and high fuel economy makes it a better buy than any other heater of its kind to achieve much lower drying costs than standard conventional ovens.

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 1700 C.


The Hot Air Generator is 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 hot air generator are the M.S. inner & outer casings (inner S.S. casing optional) which is directly above the combustion chamber, a specially designed nest of hot air tubes, a flue gas outlet, refractory lined furnace at the bottom with a forced draught hot air circulating blower.

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.

Low Operation 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 look at the other fuel options available.

The UNITHERM solid fuel fired Hot Air Generator provides multiple fuel options, 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' solid fuel 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 1700 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. Separate External furnace at bottom with large combustion volume & high grate area can easily burn most low grade solid fuels like high ash Coal, lignite, husk, wood, bagasse etc,
7. Bypass chimney on external furnace with damper for heat control, in case of power failure.
8. Specially designed, heat resistant fire bars made from close-grained cast iron give long operational life.
9. Outside the purview of I.B.R.
10. Sturdy and simple construction.
11. Trouble free operation.
12. Can be connected to existing or new dries without any modifications.
13. Low motive power requirements.
14. Quick after sales service available.


Unitherm's Solid Fuel Fired Hot Air Generators are available in wide range of capacities from 50,000 Kcals/hr - up to 20,00,000 Kcals/hr Operating Temperatures -Upto 1700C.