Optimum Design of Equipment Structure of Yarn Package Dyeing Machine

1 Dye liquor circulation system

The dye liquor circulation system is a structure provided for the exchange of dye liquor and dyed objects in the dyeing process. It must ensure that all points of all dyed objects in the same tank get the same exchange and frequency. uniformity of temperature. The difference of the system structure will inevitably produce different results. Therefore, people have carried out a large number of experimental researches and continuously improved to form their own structural characteristics. From the perspective of reducing the liquor ratio, the less space occupied by the dye liquor circulation system, the better, because it can reduce the amount of water stored. But as far as the actual situation is concerned, excessively reducing the water storage in the circulation system will reduce the free circulating dye liquor (excluding the circulating dye liquor absorbed by the yarn), which will bring some adverse effects. We know that the dye liquor has a very important task in the circulation process, that is, the concentration difference and temperature difference of the dye liquor are reduced, and it is completed by the free circulating dye liquor in forced convection. The smaller the range, the better. From this point of view, the concentration difference and temperature difference of the dye liquor should be controlled in the main circulation pipeline, and a certain space and time should be given (limited, of course), so that it can be fully carried out in the forced convection, so that it can enter the main circulation pipeline. The concentration and temperature of the dye liquor in the cylinder are uniform, ensuring that all yarns have the same dyeing conditions at all points. This is very important for large-capacity cylinders.

From the point of view of fluid mechanics, the dye liquor should have good hydraulic characteristics in the main circulation system, and minimize the local and along the resistance loss. The local resistance loss mainly occurs in the reversing device, the heat exchanger and the elbow, and the resistance loss along the way mainly occurs in the circulation pipeline. Adopting a smooth and smooth transition, shortening the tube length and other optimized design structures can reduce hydraulic losses.

As the power source of dye liquor circulation, the main circulating pump should have high efficiency and good anti-cavitation performance. Since the main pump of most of the cylinder dyeing machines currently adopts AC frequency conversion control, according to the requirements of synchronous dyeing control, the flow and head of the main pump can be changed within a certain range, which requires that the characteristic curve of the main pump must be smooth and smooth. Hump phenomenon, otherwise the flow and head will fluctuate during the change process, resulting in unstable dye liquor circulation flow and affecting the dyeing process.

2. Increasing the effective volume of the main tank can reduce the dye liquor bath ratio. At present, this structural optimization design is mainly manifested in the following aspects.

1) The distribution of the core rod of the cheese yarn. By adopting the distribution of incomplete concentric circles, it is possible to set more yarn core rods than the distribution of concentric circles within the same range.

2) The form and space utilization of the bottom head of the master cylinder. There are two types of heads at the bottom of the master cylinder: oval head and dish head. From the point of view of the force of the pressure vessel, the oval head is better than the dish head, but the volume of the dish head is smaller than that of the oval head. For the elliptical head and the dish-shaped head of the same diameter, the difference in force has little effect on the thickness after the strength calculation. Therefore, many types of dish-shaped heads are currently used. If the heat exchanger is placed outside, the dye cage can also be moved down a part, making full use of the inner space of the head.

3) The aspect ratio of the main cylinder

If the height of the top surface of the top yarn submerged by the dye liquor level of the main vat is constant, then the amount of the top dye liquor is proportional to the square of the cylinder diameter. That is to say, for the main cylinder of the same capacity, the bath ratio of the larger diameter and lower height is larger than that of the smaller diameter and higher height (the volume difference of the dye solution between the upper end of the cylinder and the bottom head).

Therefore, the vertical package dyeing machine has a tendency to develop towards high-level yarns. Of course, the corresponding changes in the head of the main pump and the structure of the dyeing cage must be comprehensively considered. Otherwise, there may be a color difference between the upper and lower package yarns.

4. Application of advanced control technology

The development of Yarn Package Dyeing Machine technology can be said to be largely reflected in the development and application of control technology. In the past, many processes that were operated by human experience are now controlled by automatic programs. This not only eliminates human influence factors and improves the reproducibility of dyeing, but also improves production efficiency and brings better economic benefits to manufacturers.