Water Jet Loom: History, Working Principle, Advantages and Disadvantages

Last Updated on 19/08/2022

Water Jet Loom:
Jet weaving looms are divided into air-jet loom and water jet loom according to the medium of weft insertion. The weft thread is transported through the shed with the help of air or water jets. Secondary jets located in the shed assist the main jet in transporting the thread. This technology can only be used for lightweight fabrics. Jet looms have the highest weft insertion speeds of all looms, but they are limited with regard to suitable weft materials. Water-jet loom can produce superior high quality fabrics that have good appearance and feel.

A water jet loom is similar to an air jet loom but uses water instead of air to transport the yarn around the shed. A water jet loom inserts the filling yarn by highly pressurized water. The tractive force is provided by the relative velocity between the filling yarn and the water jet. If there is no velocity difference between the water and yarn, then there would be no tension on the yarn which would result in curling and snarling of the yarn. The tractive force can be affected by the viscosity of the water and the roughness and length of the filling yarn; higher viscosities cause higher tractive forces. The viscosity of water depends on the temperature.

Water-jet weaving machines are produced only by few companies and are used for the manufacture of light and medium weight fabrics with standard characteristics and in water repellent fiber materials, primarily multi-filament synthetic yarns. Water jet machines are extensively used in East Asia, but have limited importance in other countries. They are characterized in particular by high insertion performance and low energy consumption.

Water jet loom is not used as frequently as air jet, but they are preferred for some types of fabrics. The process is unsuitable for yarns of hydrophilic fibers because the fabric picks up too much moisture. Water-soluble warp sizings are used on most staple warp yarns. Therefore, the use of water jet loom is restricted to filament yarns of acetate, nylon, polyester, and glass; yarns that are non absorbent, and those that do not lose strength when wet. Furthermore, these fabrics come off the loom wet and must be dried. In this technique a water jet is shot under force and, with it, a weft yarn. The force of the water as it is propelled across the shed carries the yarn to the opposite side. This machine is economical in its operation. A water jet of only 0.1centimeter is sufficient to carry a yarn across a 48 inch shed. The amount of water required for each weft yarn is less than 2.0 cubic centimeters. Water jet loom can reach speeds of 2,000 meters of picks per minute.

Both air and water jet weaving machines weave rapidly, provide for laying different colors in the weft direction, and produce uniform, high quality fabrics. They are less noisy and require less space than most other types of loom. They cause Minimal damage to warp yarns during the weaving operation, because the air or Water jets are less abrasive than moving metal parts.

The speeds of shuttle less weaving machines can be compared by measuring the picks per minute (ppm) or the yards laid per minute (ypm) in weft insertion. In 1990, the top speed for a projectile weaving machine was 420 ppm with between 1000 and 1203 ypm weft insertion. Flexible rapier weaving machine operated at 524 ppm and rigid rapiers at 475ppm, laying weft at up to 1404 and 930ypm, respectively. Air jets could lay as many as 1200 ppm and water jets up to 1500 ppm, laying 2145 and 2360 ypm, respectively.

If a fabric 60 inches wide is woven on each machine at a density of 50 picks per inch, approximately 84 yards of weft yarn would be needed to produce an inch of fabric. In theory, the projectile loom would produce approximately 8.4 inches of fabric per minute; the flexible rapier, 10.5 inches; the rigid rapier, 9.5 inches; the air jet, 24 inches; and the water jet, 30 inches. The slowest of the new machines could produce a yard of fabric in 4.3 minutes, and the fastest would take just 1.2 minutes. Seldom do weaving machines operate at full capacity, but even at 50% efficiency such machines could produce a yard of fabric every 2.5 minutes.

History of Water Jet Loom:
Water-jet weaving machines were first developed in Czechoslovakia in the 1950s and Subsequently refined by the Japanese in the1960s. The first water-jet weaving machine was KOVO, which was developed by Vladimir Svaty at the Research Institute for Textile Technology in Czechoslovakia and shown at the Brussels Textile Machinery Exhibition in 1955. This machine had a speed of 600 ppm with a reed width of 40 inches. Up to 12 harnesses were possible. The Prince Jet loom was another earlier water-jet weaving machine. It had a reed width of 65 inches at 400 ppm speed. The width and speed of the water-jet looms gradually increased and the modern water-jet weaving machines can have a speed of around 1,500 ppm while the maximum reed width is 3 m and the filling insertion rate is 1800 mpm.

Working Principle of Water Jet Loom:
Water-jet weaving machines have the same basic functions of any other type of weaving machines. The principle of filling insertion with a water-jet is similar to the filling insertion with an air-jet: they both use a fluid to carry the yarn. However there are some differences that affect the performance and acceptance of water-jet weaving machines. For example, the yarn must be wettable in order to develop enough tractive force.

The flow of water has three phases: 1) acceleration inside the pump prior to injection into the nozzle, 2) jet outlet from the nozzle, 3) flow inside the shed. The water flow inside the shed has a conical shape with three regions: compact, split and atomized.

Compact and split portions are better for yarn insertion. Due to water weight, the jet axis forms a parabola which necessitates adjusting the axis of the nozzle upward by some angle. The flow of water then follows the motion of angular projection.

Unlike the air-jet weaving machines, the pump and picking system is fixed firmly to the machine frame to ensure that the beat-up mechanism moves the reed only. Due to the viscosity of water and its surface tension, a water-jet is more coherent than an air-jet. As a result, the water-jet does not break up that easily and has a longer propulsive zone. There are no varying lateral forces in a water-jet to cause the filling yarn to contort. Besides, since the wet moving element is more massive, there is less chance for the filling yarn to entangle with the warp. The braking of the filling yarn is provided by the reed.

The width of a water jet loom machine depends on the water pressure and diameter of the jet. Since water is not compressible, it is relatively easy to give enough pressure to the water-jet for insertion. The diameter of the jet is around 0.1 cm and the amount of water used for one pick is usually less than 2 cc. Double pump system, with two nozzle at will filling insertion, is suitable for weaving fabrics with two different fillings.

The wastewater after insertion is usually removed into a drainage system.

Mazharul Islam Kiron

Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. He is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.

Share this Article!