Find out about the differences between IR and hot-air dryers and discover which features might be most useful to your operation.
Size The electricity consumption of a 36-in. dryer with a 6-ft drying chamber is relatively modest and does not raise any concerns about operating cost. However, if you were to use an IR dryer with the same design for a 76-in.-wide dryer and 16-ft-long drying section, then the operating cost for the electrically heated infrared elements could be many times higher than what you’d pay for a gas-heated air-jet dryer. The increase in size of the IR dryer also leads to increased difficulty in controlling the temperature throughout the dryer. The result is uneven temperature throughout the dryer, known as hot spots, which can jeopardize good and safe curing of the ink.
The hot-air jet dryer
The hot-air jet dryer blows forced hot air over printed garments. The air can be heated by electric heating elements (coils) or by a gas burner, depending on availability and the most economical power supply—electric or gas—in a given geographical area.
The airflow is generated by a large fan positioned at the base of the dryer, and air is blown through the heater and up into a drying hood above the conveyor. The hot air then pressurizes the heat chamber and is forced out onto the printed garment through a special system of high-speed nozzles. The air is then returned through the mesh conveyor belt to the circulation fan. Capturing the air in this way keeps it in constant recirculation over the heating elements or through the gas burner to ensure that the air temperature is kept constant within a few degrees of set value.
A separate exhaust fan removes fumes and vapors released during the curing process, which then are exhausted out of the dryer while the dryer is then replenished with fresh air from the printing room.
The hot-air jet dryer is often more complex in its design and function than the IR dryer, and it requires a certain degree of maintenance and a higher level of investment. However, it offers some very important advantages in return. For instance, all printed garments and inks, such as plastisols, water-based inks, discharge inks, and specialty inks can be cured in the same hot-air dryer. Other examples follow.
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