The same heating equipment used to dry wet textiles can also be used to heat the fabric and finish to the temperatures desired for optimal curing. For equipment, it must be remembered that the temperature of the fabric cannot exceed 100¡æ until all of the water has been removed. Fig 1. demonstrates this effect. The fabric temperature does not rise to the set temperature until after all the water has gone.
When drying and curing are done separately in two steps, the curing time can be controlled easily. As speed is defined by distance divided by time, the curing time can be calculated by equation:
curing time=(amout of fabric in machine)/(speed of the fabric through the machine)
For example, if the fabric content of the machine is 20 m and fabric speed is 40 m min-1, then the curing time is 0.5 min. Often drying and curing are combined in one process, for example the so-called shock-condensation or shock-curing process. As the end of drying phase is not easy to determine, there is a risk of over-or under-curing with many disadvantages. The best available solution for this problem is curing controlled by the temperature of the fabric. As shown in figure 1. only when all the water is evaporated, will the temperature of the fabric is exactly measured free of contact. Thereby the end of the drying step and the time of the curing step can be determined and monitored. As radiation pyrometers are relatively expensive, often not all the section of long tenters are completely monitored by ploymeters; they are concentrated in and most important in the tenter section where drying ends and curing starts.