Infrared Absorption Studies of Fabrics

Abstract

A technique is discussed in this paper for evaluating the performance of IR emitters in heating and drying fabrics. The efficiency of IR heating depends on both the fabric spectral absorption characteristics and the spectral emission of the infrared source. An FTIR spectrometer with an integrating sphere is used to measure the infrared absorptivities of fabrics over the range of wavelengths from 0.7 to 25 microns (the range of operation of commercial infrared emitters). Spectral absorptivities are used with the normalized emission characteristics of blackbody emitters to calculate average fabric absorptivities for blackbody emitter temperatures ranging from 500 to 3000 K. Overall radiant efficiencies for heating fabrics with blackbody emitters are calculated by multiplying average fabric absorptivities by the radiant efficiencies of emitters in converting input power to IR radiant output power. The effects of fabric characteristics on spectral absorptivities, average absorptivities, and overall radiant efficiencies are studied. Parameters include fiber type, fabric weight, moisture regain, fabric construction, and dyeing. The technique used in this investigation is useful in matching IR emitters with applications for the textile industry.