What is a Water Jet Loom?
Water-jet loom use highly pressurized water as a medium for weft insertion. Due to the viscosity of water and its surface tension, a water jet is more cohesive and does not break up easily. It has a longer propulsive zone. Because there is no lateral force in a water jet, the weft yarn does not contort. Only a single main nozzle is used in water-jet weaving machines. Water pressure and the diameter of the jet determine the width of the weaving machine. The amount of water per pick is usually less than 2cc. A pump is used to generate the required pressure for the water jet.
Nozzles are employed to disperse high pressurized jets of water to propel the weft yarn through the shed arrangement. This method is the fastest shuttleless weft insertion method. Water-jet weaving, however, is limited to weaving hydrophobic fibers/yarns, (water-resistant) such as nylon/polyester.
Water-jet loom has the same basic functions of any other type of loom. The principle of filling insertion with a water jet is similar to that of an air jet, as both uses a fluid to carry the yarn. However, there are differences that influence the performance and acceptance of water-jet loom.
Water-jet looms are the least flexible. The fabric woven must be hydrophobic, and only medium-weight fabrics can be woven successfully, even though lightweight fabric can be woven with great difficulty. Yarn wastage is more in water-jet looms. Nevertheless, water-jet looms are best suited to produce 100% filament fabrics on a mass scale. Water-jet looms use less energy and are the least noisy.
Working Principle of Water Jet Loom:
In a water jet loom, a miniature pump is used to feed water under pressure to the nozzle. The water carries the weft from one end to another. Working principle of a water-jet loom revolves around the use of water as a medium to insert the weft yarn into the warp shed. The process begins with the warp yarns being supplied from the warp beam and passing through the heald frames and reed to form the shed. The heald frames then separate the warp yarns into two layers, creating an opening for the weft yarn to pass through. A high-pressure water jet, directed by a nozzle, propels the weft yarn across the shed with enough force to reach the opposite side of the loom. Once the weft yarn is in place, the reed pushes it firmly against the fell of the cloth, ensuring proper alignment and tightness. As the weaving progresses, the woven fabric is rolled onto the fabric beam while the warp yarns are unwound from the warp beam to maintain consistent tension. This process enables high-speed weaving, but its application is limited to wettable and water-resistant yarns. Figure 1 shows the schematic of a water-jet weft insertion. For weft feeding, a measuring drum is used to supply the weft, which supplies exact length of weft for each pick.
Weft yarn is drawn from package 1 by the measuring drum and pressure roller 3 and fed into nozzle 5. Water from sump 9 is pressurized by pump 8 and ejected as a water jet through nozzle 5. The water jet carries the weft through the shed to the other end of the machine by tractive force. The weft tends to fall as it moves from the nozzle to the other end. Hence, its travel path is arranged in an arc form. This is achieved by adjusting the nozzle holder at an angle.
The weft is cut at the selvedge by heaters and a fused selvedge is formed. The heater temperature is around 500 °C.
All yarns cannot be used in water-jet weaving machines. The yarn must be hydrophobic in nature and insensitive to water. Thermoplastic yarns, such as nylon, polyester, polypropylene and glass, are successfully woven in water-jet weaving machines. Heaters are used to dry the cloth. The wastewater after weft insertion is collected through pipelines.
Advantages of Water Jet Loom:
A water jet loom is more coherent than an air jet loom. It does not break up so easily, and the propulsive zone is elongated, making it much more effective.
1. High Weaving Speed:
Water-jet loom can operate at very high speeds, significantly increasing production efficiency and making them suitable for large-scale production. Water-jet loom can reach speeds of 2,000 meters of picks per minute.
2. Smooth Weft Insertion:
The use of water ensures gentle and smooth weft insertion, reducing the risk of yarn damage. They cause minimal damage to warp yarns during the weaving operation, because the water jets are less abrasive than moving metal parts.
3. Energy Efficient:
Water-jet looms consume less energy than air-jet looms due to the lower energy requirements of water propulsion.
4. Cost-Effective:
Due to their simple design and lower energy consumption, these looms are cost-effective for certain fabric types.
5. High Fabric Quality:
Water jet looms can produce superior high quality fabrics that have good appearance and feel. They are less noisy and require less space than most other types of looms.
6. Suitable for Specific Fabrics:
Ideal for weaving hydrophilic yarns like polyester and nylon, which perform well with water as the medium.
Disadvantages of Water Jet Loom:
Water-jet looms come with certain disadvantages that limit their versatility and applicability. This type of loom can only work with wettable and water-resistant yarns, such as polyester and nylon. Besides, these looms require a continuous supply of clean water, which can be costly and impractical in areas with water scarcity. The environmental impact of water usage and potential wastewater disposal poses further challenges, especially if not properly managed. Moreover, the use of water increases the risk of rust or corrosion in machine components, necessitating regular maintenance.
Conclusion:
Water jet loom is highly efficient weaving machine known for its high-speed operation and smooth weft insertion, making it ideal for producing lightweight and hydrophilic synthetic fabrics. While this loom offers advantages such as energy efficiency, high fabric quality, and cost-effectiveness, their applicability is limited by the need for wettable yarns, water dependency, and environmental considerations. Despite these challenges, water-jet looms remain a valuable choice in industries focused on producing specific types of fabrics, such as apparel, home textiles, and industrial materials, where their unique capabilities align with production requirements.
References:
[1] Thangamani, K., & Sundaresan, S. (2022). Fabric Manufacturing Technology: Weaving and Knitting. CRC Press.
[2] Textile and Clothing Design Technology. (2017). In CRC Press eBooks. https://doi.org/10.1201/9781315156163
[3] Adanur, S. (2020). Handbook of Weaving. CRC Press.
[4] Purushothama, B. (2016). Handbook on Fabric Manufacturing: Grey Fabrics: Preparation, Weaving to Marketing. Woodhead Publishing India in T.
