Development and research of flexible fabric electric heaters

EXPERIMENTAL PROCEDURES AND MATERIALS 
Different arrangement of the electrically conductive thread in the fabric (in the warp and weft), their density in the 
fabric (the number of ECYs per 10 cm), the amount of the current supply electrodes per unit length of the fabric and 
applying them with different resistivity depending on their cross section and materials, we can make woven heaters 
with almost any specified electrical parameters. The main of the important parameters of heating fabrics is the 
electrical resistivity, which, in addition to the above parameters, also depends on deformations that occur during fabric 
formation (during preparatory operations, resetting, and during fabric production on the machine) after removal from 
the machine, (relaxation process), when preparing heating elements, when influenced by operating temperatures [9-
11]. 
In the simplest cases, woven heаters contain two systems of filаments: one of the systems contаins electrically 
conductive filaments, аnd the other — insulаting. Depending on the locаtion of the electrically conductive аnd current-
carrying tire in the fаbric, there are main and weft woven electric heaters. Basically, the electric heaters of the 
electrically conductive thread are located along the fabric (warp), and the conductive bus across the fabric (weft), and 
the weft heaters, on the contrary (Fig.3) [9]. 
(a) (b) 
FIGURE 3. The location of the conductive yarn in the fabric a) on the by weft; b) on the by warp 
The first type of thread is most often used as a heating element, since they have less longitudinal elastic deformation 
compared to textile threads and they do not shrink, slight deformation of the heating element can occur due to tissue 
relaxation after removal from the weaving loom or shrinkage of textile threads under the influence of operating 
temperature. 
MATERIALS 
The use of a metal thread in the manufacture of heating fabrics requires a special technological process when 
preparing the thread for weaving. When used as a warp, depending on the width of the fabric and on the electrical 
resistance of the thread, a certain number of threads is required, which requires special bobbins to provide the required 
thread tension. In addition, depending on the connection method (parallel or serial), the contact points of the 
connection increase. Especially with a serial connection, a break in the thread of any point leads to a break in the 
electric current. Here, one must also take into account the oxidation of the metal, i.e. the impact of the external 
environment (humidity, weather, etc.) 
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Woven flexible electric heaters have been developed and researched. A yarn with the following properties was 
used as an electrically conductive component of fabrics: -linear density-50 tex (blended yarn 60% cotton + 40% EСY), 
electrical resistance 20-35 kOhm /m. Fig. 4. shows the scheme of threading the fabric on the weaving loom. 
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