In an indirect-fired generator, the combustion takes place inside a high-temperature stainless steel heat exchanger. The process air passes over the external surface of the exchanger, absorbing heat without ever coming into contact with the actual flame or flue gases.

• Direct Fired: The flame is in the airstream; flue gases mix with the process air (highest efficiency, but air is not 100% clean).
• Indirect Fired: Flue gases are exhausted via a chimney; the process air remains 100% clean and contamination-free.

Standard units from indianboilers.com provide hot air from ambient up to 400°C. Custom designs for higher temperatures are available upon request for specialized metallurgy.

Our burners are versatile and can be configured for:

• Liquid Fuels: HSD (High-Speed Diesel), LDO (Light Diesel Oil), or Furnace Oil.
• Gaseous Fuels: Natural Gas (NG), LPG, or Propane.

Our indirect-fired systems generally offer 80% to 85% efficiency, while direct-fired systems can reach up to 95-98%.

Yes. Most of our units are designed to accommodate a burner change. By simply replacing the burner assembly and adjusting the controls, you can switch fuel types based on market prices.

We offer a wide range of capacities, measured in heat output (kcal/hr), ranging from 50,000 kcal/hr to 5,000,000 kcal/hr.

We integrate world-class, fully automatic monoblock burners that ensure optimal fuel-air mixing, low emissions, and reliable ignition.

The units feature a fully automated control panel with a digital temperature controller. The burner modulates (High/Low or Stepless) to maintain the set temperature with high precision.

They are essential in:

• Chemicals & Fertilizers: For spray dryers and flash dryers.
• Ceramics: For spray drying of clay slip.
• Textiles: For stenters and curing chambers.
• Agriculture: For large-scale grain and seed drying.

With our Indirect Fired models, the air is 100% clean and free of combustion by-products, making it perfectly safe for drying spices, milk powder, and other food items.

Steam systems are limited by the pressure of the boiler. An Oil/Gas Hot Air Generator can reach much higher temperatures (above 200°C) more efficiently than a steam-to-air heat exchanger.

At indianboilers.com, safety is a standard feature. Our units include:

• Flame sensors (Photocells) to prevent fuel build-up.
• High-temperature safety cut-offs.
• Blower-burner interlocks (Burner won't start without airflow).

Yes, for indirect-fired units, a chimney is required to vent the combustion gases safely outside the facility.

We recommend a major service every 6 months, focusing on burner cleaning, nozzle replacement, and inspection of the heat exchanger for any soot build-up or cracks.

Constructed with high-grade stainless steel (SS 310 or SS 316), our heat exchangers are designed to last 10 to 15 years with proper maintenance.

The unit requires a level concrete plinth, a fuel storage tank, electrical connection, and ducting to connect the hot air outlet to your process equipment.

By replacing inefficient heating methods or moving to cheaper fuels like Natural Gas, most clients see a complete ROI within 12 to 18 months.

Contact our engineering team through the indianboilers.com contact page. Please provide your required Air Flow (m³/hr) and Inlet/Outlet Temperature for an accurate quote.

The price varies significantly based on capacity (Kcal/hr) and technology. In India, a standard industrial oil or gas-fired hot air generator typically starts from ₹10 Lakhs for small-scale units (approx. 50,000 Kcal/hr) and can go up to ₹15 Lakhs to ₹40 Lakhs for high-capacity, fully automated industrial systems (1 million Kcal/hr and above).

The price is primarily driven by:

• Heating Capacity: Measured in kcal/hr. A 1 million kcal/hr unit is significantly more expensive than a 100,000 kcal/hr unit due to the size of the combustion chamber and burner.
• Direct vs. Indirect Firing:
  • Direct Fired: Cheaper, as the flue gases mix with the air. Used for non-sensitive materials like minerals.
  • Indirect Fired: More expensive (20% – 40% more) because it uses a heat exchanger to keep the process air clean. Essential for food, pharma, and chemicals.
• Material of Construction (MOC): Mild Steel (MS) is the standard and most affordable. Stainless Steel (SS 304 or 316) increases the price but is necessary for high-temperature or corrosive environments.

Usually, the "shell" of the generator is similar. The price difference often lies in the Burner:

• Gas Burners: (Natural Gas/LPG) can sometimes be slightly more expensive due to complex gas trains and safety valves.
• Dual Fuel Burners: These allow you to switch between oil and gas. These are the most expensive burner options but offer the best fuel flexibility.

Yes. Standard units usually provide air up to 200°C – 300°C. If your process requires high-temperature air (up to 600°C or higher), the unit will require specialized refractory lining and high-grade alloys, which can double the cost.

Beyond the machine price, consider:

• Installation & Commissioning: Usually 5% – 10% of the machine cost.
• Ducting & Insulation: Bringing the hot air to your process equipment.
• Fuel Storage: Tanks for oil or gas pipeline infrastructure.
• Chimney/Stack: Depending on local environmental regulations.

Most manufacturers offer a 1-year warranty. Extended warranties or "Annual Maintenance Contracts" (AMC) are often available for an additional 2% – 5% of the purchase price, which can be a wise investment for high-uptime industrial plants.