Dyeing, Drying, Finishing
Switching to carbon infrared emitters halves the drying time for screen-printed t-shirts
Calmatech BV is a globally-acknowledged manufacturer of flash cure dryers and tunnel dryers for the textiles industry, with over 20 years experience of drying and heating technology. Its products are used worldwide for drying inks in digital and screen printing, along with inks that are employed in the printing of transfers on textiles, glass, porcelain and metals. In the textiles sector, Calmatech dryers can be fitted to carousels as well as mobile stands.
The company strives to incorporate the latest technologies in infra-red and electronics to improve the efficiency and effectiveness of its dryers. A recent development saw it replace halogen infra-red lamps with medium wave, carbon infra-red emitters from Heraeus. The medium wavelength is optimally suited for surface drying, as this wavelength closely matches the absorption characteristics of water. By contrast, the short wavelength of halogen lamps is more penetrative so that energy is lost as it penetrates the ink and the textile itself.
Since the replacement, the new emitters, which are fitted precisely in the dryers to create an even heat distribution over the target textile surface. These are easily programmable by an operator or by automated controls, this has demonstrated significant energy savings. This is because of the better water-removal capability of medium wave radiation and also because carbon emitters have a very short response time. Consequently, they are suitable for pulsing and are switched on only when required, in contrast to the halogen emitters, which needed to be switched on permanently.
Jurgen van Oostrum, managing director at Calmatech, is extremely pleased with the innovation. He says, The switch to carbon emitters has made our flash curers much more efficient. Formerly, it took seven to eight seconds to dry screen inks with the halogen system. With the carbon emitters it now takes just two to three seconds. This is of great benefit to our customers, who are very appreciative of the energy savings resulting from the reduced drying times. They are also very pleased with the fact that the less-penetrative medium wave dries the textile surface more gently, without discolouration and without heating the print pallet.
Copyright Calmatech BV, Beugen, Niederlande 2018
Saving Energy with the exactly fitting wavelength
The wavelength of the infrared radiation has a significant effect on drying. Water evaporates particularly quickly when irradiated with medium wave infrared. This is because medium wave radiation is particularly well absorbed by water and is converted directly into heat, in contrast to very short wave near infrared. The Heraeus Carbon emitters were developed precisely for the medium wave region.
All Carbon emitters combine the effective medium wave radiation with high surface power density to accelerate the highly efficient drying of water-based paints and lacquers. The British company Orvec has used these features to provide non-slip coatings on disposable tray mats manufactured for many major airlines. This involved applying a water-based solution on the mats and then drying this as quickly as possible, a task which was carried out effectively and efficiently with Carbon emitters.
Extensive research has shown that a Carbon infrared emitter requires up to 30% less energy than a conventional short wave emitter to carry out the same drying process.