After leaving the size box, warp sheet must be drying. There are different drying methods in sizing is used. When warp sheet leave the size box, the warp sheet is impregnated with wet size paste about 90%-140% of its own weight. During drying, moisture is completely removed from the size paste, but it is retained in the yarn at the same time. This is especially true for yarns made from cellulosic or other natural fibers. It is to be noted here that the degree of drying ‘largely influences the yarn properties such as strength, flexibility, brittleness, plasticity and so on. Also, drying rate determines the speed and production of sizing machines. As a result, the drying process should be carried out in such a way that the yarn’s desirable properties are retained while keeping production costs and energy consumption low. During the drying process, the timing and temperature play a crucial role, so care and caution must be exercised to avoid over and under drying of yarns, which could lead to problems in the next step.
Drying Methods in Sizing:
In this article, I am going to describe some of the popular methods of drying that are used in the sizing machines. They are:
- Conduction method.
- Convection method.
- Radiation method.
1. Conduction Method:
In this method, the warp sheet’s drying is affected by the conductor or transmitter of heat from the drying cylinder’s metallic surface, which is heated by steam. The contact drying method, also called contact drying, is the most popular method of drying for slasher sizing machines, and it is also very economical in terms of energy consumption. However, this method does have one drawback in that when yarn is in contact with the cylinder, there will be a degree of flattening that occurs.
2. Convection Method:
This method of drying has had a profound effect on the circulation of hot air around the drying zone of the warp sheet. As with the previous method, there are several advantages to using this method. First, this method does not flatten the yarn, as it did previously. The air may be heated electrically or with steam. Fan and ducts circulate the hot air.
3. Radiation method:
In this method, the wrap sheet’s drying is affected by heat transferred to it by direct radiation. In order to accomplish this, it is important to use electrical heaters. They are used to transmit heat waves from the heater to the yarn through electromagnetic radiation, which removes any water present in the yarn. Similarly to the previous method, this method does not flatten the yarn as there is no contact surface between the yarn and the heater. In terms of energy consumption, it is considered very poor, and is therefore rarely used as a result. However, it can be used for a variety of purposes, including laboratory tests and large-scale operations requiring a rapid drying process.
A high-quality and efficient sizing operation depends heavily on the methods of drying in the weaving section’s sizing process. Drying is primarily concerned with removing excess moisture from warp yarns after they have been coated. To prevent issues such as warp breakage, weaving defects, and poor fabric quality, this step is necessary to ensure the proper adhesion of the sizing material to the fibers. Please feel free to ask any questions you might have regarding this article, by writing them in the comments box below.
- Adanur, S. (2001). Handbook of weaving. Boca Raton: CRC press.
- Gandhi, K. (2012). Woven Textiles. New Delhi: Wood Publication Limited.
- Gokarneshan, D. N. (2009). Weaving Preparation Technology. Delhi: Abhishek Publicaions.
- Rahman, M. M. (2008). Fabric Manufacturing Technology. Dhaka: Books Fair Publications.
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