Air flow dyeing, due to the small liquor ratio, not only saves energy, reduces pollution and protects the environment by saving water, steam and dyeing materials, but also has a short dyeing cycle, good dyeing effect, no damage to the fabric and excellent hand feel. It is especially suitable for the processing of some high-value-added high-end fabrics, so it has attracted more and more people’s attention and attention. However, airflow dyeing technology, like other dyeing technologies, will encounter some problems in the actual application process, such as poor dyeing tubes and vats, pilling, creases, and spots on the fabric.
1. Pipe difference
Pipe difference refers to fabrics in the same cylinder During dyeing, the dyeing color difference between tubes of fabric.
There are many reasons for pipe differences. The direct causes are analyzed as follows:
(1) The distribution amount of each pipe difference. In air-flow dyeing, the exchange of dye liquor and fabric is completed in the nozzle system. The frequency of exchange is related to the cycle of fabric circulation. The cycle of fabric is determined by cloth speed and cloth length. Cloth speed is controlled by air volume and cloth lifting roller speed. Generally speaking, the cloth speed of each tube of the same machine is basically the same. Therefore, if the cloth length of each tube is too different, there will be a large difference in the cycle of each tube’s fabric operation. That is to say, during dyeing Within a period of time, the number of exchanges of fabric and dye liquor in each tube will be greatly different, resulting in poor dyeing tubes.
(2) Difference in cloth speed. In air-flow dyeing, the number of exchanges of dye liquor and fabric is determined by the circulation frequency of the dye liquor and the cloth speed. In dyeing in the same vat, the circulation frequency of the dye liquor in each tube is the same. Therefore, when the cloth length of each tube is basically the same, If the difference in cloth speed is too large, it will cause a large difference in the number of exchanges between the fabric and the dye liquor, resulting in tube errors.
(3) The dye liquor nozzle is clogged. Severe blockage of the dye solution nozzle will cause the dyeing to be unable to continue, which is completely not allowed. Slight blockage, although it does not affect the continued dyeing, may cause poor dyeing pipes because, under normal circumstances, the caliber of each nozzle It is basically the same as the spray volume, but if there is a blockage, the spray volume may be different. When the difference in the spray volume of each nozzle is large, dyeing tube differences will occur. The cause of clogging is that lint, or too much long lint and other debris enter the nozzle and cannot be washed away by the dye solution.
(4) Leakage of air flow nozzle. In the nozzle system, the airflow nozzle is installed on the nozzle seat. After installation, there should be a good seal between the fabric inlet side of the airflow nozzle and the gas-liquid two-phase mixing chamber. If the sealing is not tight, firstly, it will affect the dye liquor. Secondly, the atomization effect is that the dye liquor will leak to the inlet side of the air flow nozzle. If the leakage is serious, it means that the amount of dye liquor participating in the exchange with the fabric in the nozzle system is reduced. This leakage of the air flow nozzles in each tube will cause problems with the atomization effect. When the difference between the dye liquors exchanged by fabrics is large, pipe errors will occur.
Therefore, based on the above reason analysis, in order to prevent poor dyeing tubes, attention should be paid to standardized management and scientific arrangements in production, so that the distribution volume of each tube cannot be too different. In operation, pay attention to adjusting the consistency of the cloth speed of each tube. The cloth speed is controlled by the air volume and the speed of the cloth lifting roller. The distribution of air volume in each tube has taken into account its balance from the structural design principle, so attention should be paid to adjusting the cloth lifting roller of each tube. Speed consistency.
For nozzle clogging:
First, during the initial equipment commissioning and test run, pay attention to checking the nozzle and cleaning it several times. Pipelines and cylinders should be cleaned of debris remaining due to manufacturing or transportation and installation;
Second, the gray cloth should be sewn, and at the same time, the plastic or paper on the cloth should be The quality label should be torn off to avoid the lint or label falling off during the dyeing process, causing clogging of the filter, pump or dye solution nozzle;
Third, clean the filter in the filter regularly ;
Fourthly, during the production process, you should always pay attention to changes in nozzle pressure. If the nozzle pressure increases, it means that the nozzle is clogged, and it should be cleaned in time.
The leakage of the airflow nozzle is related to the connection method, sealing structure and installation. If the installation is in place and there is still a large leakage, it means that the sealing and connection structure of the airflow nozzle exist. If it is insufficient, it should be improved and replaced. The airflow nozzle is a key component, and equipment manufacturers generally have their own patent protection.
2. Cylinder difference
Cylinder Difference refers to the dyeing color difference that occurs when dyeing in different dyeing vats.
The reasons for pipe differences may also cause cylinder differences between cylinders. In addition, there are other factors such as technology, equipment, operations, etc. that may also cause cylinder differences. It will cause cylinder difference.
(1) Cylinder arrangement and distribution. When mass production of the same color occurs, issues such as cylinder arrangement and distribution volume will be involved. If the cylinder types are the same and the distribution amount of each cylinder is different, cylinder differences may occur. If there are several vat types, such as a two-tube dye vat and a four-tube dye vat, differences in vat types may also cause vat differences. Therefore, when arranging the vats, we should try our best to ensure that a batch of cloths of the same color are dyed in the same vat type dyeing vat. If the same vat type dyeing vat cannot be arranged, attention should be paid to the color mixing and color matching during the production process.
(2) Process consistency. same�The cloth may be squeezed during the sliding process in the cloth storage tank by its own weight, which may not only cause creases, but may also pinch the cloth.
Therefore, in order to avoid creases during airflow dyeing, when the fabric bundle diameter is large, an airflow nozzle with a large diameter should be used so that the fabric passes through the airflow nozzle at a A relatively relaxed state without excessive meridional tension. When the fabric is fed into the cylinder, it should be straightened and not twisted to prevent the airflow from blowing open the fabric. The air volume should not be too small, as it will not blow the cloth open, nor should it be too large, as it will easily cause fluffing and pilling. In principle, it is better to just blow the cloth open. The cloth speed can be adjusted by controlling the speed of the cloth lifting roller. As for the equipment itself, the gap design between the polytetrafluoroethylene tubes in the cloth storage tank should be reasonable and the manufacturing gap should be uniform.
5. Defects
During air flow dyeing, the dye liquid is gas-liquid in the nozzle shell The two phases are mixed, and then the dye liquor is further atomized through the air flow nozzle. Theoretically, the greater the air volume, the faster the air flow in the nozzle, the greater the energy, and the easier it is to atomize the dye liquor, but in fact, it is almost impossible to atomize all the dye liquor passing through the air flow nozzle into mist. Impossible. There are always some dye liquors that are sprayed onto the fabric in the form of larger bead-shaped particles. These bead-shaped dye liquors are accelerated by high-speed airflow and have considerable energy. When they hit some light and thin yarns with relatively weak structural strength, When the bead-shaped dye liquid hits the fabric, the weft or warp threads in the hit area will be displaced, resulting in fabric defects.
To avoid such fabric defects during the dyeing process, it is necessary to reduce the impact force of the beaded dye liquor on the fabric, that is to say, the speed of the beaded dye liquor must be reduced to Reduce its kinetic energy, which can be met by reducing the air volume and reducing the airflow speed. Therefore, for some relatively delicate and light fabrics, in order to avoid fabric defects during airflow dyeing, the frequency of the fan motor should be reduced to reduce the air volume, and the frequency of the cloth lifting motor should be increased to meet the cloth speed requirements.
6. Conclusion
Air flow dyeing machine can be used as long as the fabric can Adaptation, reasonable process design, standardized equipment use and operation, and good production management can generally achieve satisfactory dyeing results. Those printing and dyeing companies with strong technical capabilities and early application of airflow dyeing technology are already comfortable with the application of airflow dyeing. I tasted a lot of sweetness. However, companies that are relatively late to apply airflow dyeing technology do not have enough understanding of airflow dyeing technology and equipment, or have weak technical strength. They will always encounter some problems during the application process that are difficult to solve. This article analyzes the causes of some of these common problems and proposes some solutions. With the continuous development of air-flow dyeing technology, new problems will inevitably be encountered in practical applications. This article sheds light on the topic and hopes that the majority of scientific and technical personnel will apply and study air-flow dyeing technology more and make the air-flow dyeing technology more perfect and mature. </p
