The role of water in the textile industry and reactive digital printing
As you know, water is one of the most important factors in the textile industry and is used in its various parts, so in this article we want to provide you with more information about it.
The waters in the ground are:
Precipitation: This type of water includes rainwater and snow. Before reaching the earth, due to passing through the earth’s atmosphere, these waters bring oxygen, carbon dioxide and monoxide gases to the earth’s surface in the form of a solution. In industrial cities where the air is polluted, rain and snow drops contain hydrogen sulfide and sulfur dioxide, and sometimes they are accompanied by organic substances and dust.
Surface water: The water of rivers, lakes, seas and oceans is called surface water. These waters contain carbonates and bicarbonates of calcium, magnesium, sodium, potassium, and a large amount of sulfates and chlorides of various metals, and the amount of each of these substances depends on the type of land that is in the path of the water.
Groundwater: Groundwater is formed from the penetration of surface water deep into the ground; Like water from wells and springs. Usually, when these waters penetrate into the ground, they dissolve calcareous substances and other salts and gradually become heavy. In addition to calcium and magnesium bicarbonates, these waters may contain sodium bicarbonate as well as carbon dioxide.
water refinery
The purpose of water purification is to separate waste materials from water and remove its impurities. In order to perform basic water purification, the type of water consumption must be determined first. To specify the method of water purification. For example, the water used for drinking should be light and free of suspended particles and germs. But for the water used in steam boilers, the existence of microbes is not important. ppm (one part impurity, in one million parts of water) is used to measure impurity. A table has been prepared for the suitability of water for various uses, according to which the water purification process is carried out. They put them in layers from the bottom to the top and pass the water over them.The impure water loses its suspended particles as a result of passing through the sand. It should be remembered that after some time, the strainers fail due to the closing of their holes. In this case, the holes of the strainer become “stuck” and reverse the path of the water passing through the strainer so that the particles suspended in be placed on a flat surface. And then they leave the flat surface by overflowing.
Physical water purification
The principles of physical water purification are based on filter performance. There are paper, cloth and sand filters. A strainer is a device that prevents particles larger than a certain size from passing through. Sand filters are widely used in water purification. There are two very important points in choosing a filter. Ease of cleaning pores and its cheapness. Sand filters are used in most large water treatment plants. To purify water in a large volume (such as the water of a city), several large cement pools (clarifiers), several powerful water pumps and large mixers are necessary.
Coagulation: Because impurities in water are very small and usually easily pass through filter pores, the size of particles can be increased with the help of coagulation. The joining together of small particles and creating a larger particle is called coagulation. Coagulation is done by coagulants. First, water is mixed with coagulant and mixed well. Then they pour this water into the pools through pumps. After about 6 hours, the coagulated particles settle as sediment. Then the water is filtered through a sand filter or pressure sand filter and converted into potable water by chlorination.
smooth sand
In the construction of these types of filters, round grains of silica, marble, and anthracite stones of different dimensions are used. If water is used for the preliminary treatment of the boiler, it is better not to use silica stones, because there is a small amount of Silica causes corrosion of the inner wall of the boiler
Pressure sand filters
This type of filter is made of different layers of sand that are on top of each other. In these filters, the water outlet pressure is more than one atmosphere. And it depends on coagulants for proper functioning. The method of using these filters is as follows. After adding the coagulant, the water enters the strainer without mixing and mixing the water, and the strainer quickly traps the impurities, and then the purified water comes out of its outlet pipe. This water purifier is used to supply water to factories, swimming pools and towns. One of the advantages of this device is its high operating speed (without the need for sedimentation) and its small volume.Obviously, for drinking water, you have to add chlorine to the water. (Chlorine is a disinfectant and kills germs). Usually, suitable coagulants for this type of filters are aluminum sulfate. These filters are not used to treat water that has a lot of mud.
Chemical water treatment
Chemical purification is used in cases where it is not possible to separate impurities by physical means. Special methods are required to separate each impurity. The higher the amount of these solutes, the more difficult it is to separate them. Chemical purification of water is done in two ways. These two methods are:
Precipitation method: In this method, by adding a chemical substance, the dissolved solutes are made insoluble to precipitate. The most important precipitating substances are lime and sodium carbonate. To increase efficiency, it is better to use a mixture of sodium carbonate and lime. The water whose solutes have been precipitated by chemical method is purified by physical method.
In this way, water is obtained that has given its calcium and magnesium solutions to zeolite. This water is called light water. After some time, all the sodium ions in zeolite are replaced by calcium and magnesium, and as a result, it loses its hardening effect. To revive zeolite, a concentrated solution of sodium salt is used. In this case, the concentrated salt water is moved from the bottom of the tank to the top (opposite to the time of water purification) and slowly. Until there is enough time to replace the calcium and magnesium attached to the zeolite, With the sodium present in the concentrated solution, salt is formed and the zeolite is regenerated. This process is called reverse washing. Zeolites can be used many times.
The importance of water purification in the textile industry
Some of the salts in the water combine with consumables such as soap and detergents and create substances that make dyeing and washing difficult. These impurities are also combined with the dyeing materials in the dyeing bath, creating stain-like deposits on the fabric. If there are iron and manganese compounds in the water, it causes precipitation and color change or staining of the fabric. The salts of these metals in the bleaching part cause the decomposition of the bleaching bath solution. Therefore, they should provide suitable conditions for textile operations by purifying water.
Effect of humidity on textile fibers
Static electricity is created by rubbing some objects against each other. Therefore, as a result of wear of fibers with machine parts, static electricity is generated. Air humidity affects the amount of static electricity created on fibers. Static electricity decreases with increasing air humidity. But the reduction of static electricity in fibers also depends on the type of fibers. For example, static electricity created on cotton and wool fibers can be reduced by increasing air humidity. While nylon and polyester fibers have low moisture absorption, and as a result, the static electricity in these fibers does not decrease sufficiently with the increase of ambient humidity. Static electricity causes the following problems in spinning.
Twisting the fibers around the rollers: lack of moisture causes the fibers to dry and as a result produce static electricity charges in them. The static electricity charges produced on the surface of the roller and the electricity charge of the fibers are non-identical and thus they attract each other. So the fibers wrap around the rollers.
Ballooning of fibers: The presence of static electricity in fibers may cause another form known as (ballooning) of fibers. The reason for this phenomenon is that because the static electricity charges present in the fibers are of the same name, the fibers want to move away from each other, and as a result, the production string is seen as a balloon. In such a case, if the friction between the fibers is low, the escape and scattering of the fibers from each other will increase, and as a result, the production thread will be torn and the productivity will decrease.
The effect of water in reactive digital printing
In reactive digital printing, water is one of the main elements for printing on fabric. Therefore, water and moisture are necessary to carry out the chemical reaction of reactive dye with natural fiber fabric for reactive digital printing. In this way, reactive dye molecules need water molecules to form a coulancy bond to stay on the fabric forever.
last word
Arachap Rangin Sepahan company with a brilliant history, technical knowledge and also having the latest technology in the world is able to print on natural fiber fabrics such as: cotton, viscose, linen, linen, modal, silk, wool, etc. (digitally) Reactive) and by providing the best quality in printing, it is comparable not only with domestic brands but also with foreign brands. For printing on the hem, get more information and place an order by calling 09352547048.
