Soft flow dyeing machine is a dyeing equipment widely used in printing and dyeing factories. Due to the limitations of equipment performance and functions, it is difficult to ensure the reproducibility of the dyeing process. Even if it can basically meet the requirements of the dyeing process, it is controlled by experienced craftsmen or operators. This kind of artificial control can't avoid being affected by people's technical level, sense of responsibility and emotional changes, resulting in unstable dyeing quality of fabrics, high rejection rate, and inability to improve product quality. How to ensure the reproducibility of the dyeing process and dyeing quality, it is important to formulate a reasonable dyeing process, but it is more important to eliminate human influence factors, improve equipment control functions, and more accurately control every parameter that affects dyeing quality. The whole process of the dyeing process is controlled through a certain procedure, and the controlled dyeing is realized in the function of the equipment. The function and control of the overflow dyeing machine According to the requirements of the controlled dyeing process, the soft flow dyeing machine must realize the following functions:
1. Flow and pressure control Flow and pressure are two important parameters of the soft flow dyeing machine, which are determined by the main circulating pump. The flow is necessary to ensure the dyeing exchange between the dye and the fabric, and it must be large enough. In a specific dyeing process, the change should be as small as possible. It is completely controlled by the main pump. For the overflow jet dyeing machine, the pressure refers to the pressure generated by the nozzle; for the cheese dyeing machine, it refers to the pressure difference between the inside and outside of the cheese, but the total pressure is still provided by the head of the main pump. In the dyeing process, flow and pressure play a very important role. Different fabrics and processes have different dye flow and pressure (jet force or pressure difference). For example, comparing high-count fabrics with large surfaces and fast dyeing processes, the flow rate is large; for light fabrics and fabrics with delicate surfaces, small jetting force is required; and for fabrics with a large weight, it is required to have sufficient The flow rate, but also has a strong jet force. Therefore, the flow rate and pressure should vary according to different fabrics and processes. The traditional overflow dyeing machine, in order to meet the changes in flow and pressure, is controlled by the shut-off adjustment of the outlet of the main pump. Because this control method is affected by human factors, it is not accurate enough; at the same time, the main circulating pump does not work at the best working condition point, and the efficiency is reduced. According to the characteristic curve of the main pump, within a certain speed adjustment range, the rotation speed of the main pump is changed through AC frequency conversion to achieve changes in flow and head to meet the requirements of different dyeing processes, so as to ensure that the main pump is always at the top of the corresponding flow and curve. Work on the best working conditions to save power. As for the specific determination of flow and pressure, you can set flow or pressure detection, and realize automatic control through PLC processing. Prior to this, the manufacturer is required to test the applicable fabric dyeing process, and set the successful and feasible detection value in the PLC. Users only need to select the corresponding parameter menu according to the fabric they dye.
2. Temperature proportional control. Generally speaking, as the dyeing temperature increases, the dispersion of the dye and the kinetic energy to diffuse into the fabric fiber also increase; at the same time, due to the expansion of the fabric fiber, the internal pores increase, which improves the adsorption of the dye. Diffusion ability speeds up the dyeing speed of the fabric. However, when the temperature is too high, because the fiber pores are too large, the kinetic energy of the dye particles is too large, but the dye that has been dyed on the fiber is partially re-dissolved in the dye solution. The heating program and heating rate have a great influence on the dyeing (or adsorption) rate of the fabric. Different fabrics and dyes should adopt different heating curves. Even the same fabric has different dye uptake rates in different temperature sections. For example, a high-count fabric with a larger specific surface has a high dye uptake rate at low temperatures. If the heating rate and temperature difference are not well controlled, it will be easy to dye flowers. Therefore, the temperature of the dyeing process must be controlled in proportion to accurately control the time in the temperature zone with higher dye uptake. This kind of control method mainly adopts proportional regulating valve, and completes the whole process control by PLC and computer according to the set temperature control curve.
3. Metering and feeding control The traditional dyeing process mainly controls the temperature, dyes and auxiliaries and the injection time, but the injection method of dyeing materials is not too particular. This is not a big problem for dyeing dark colors, but for dyeing light-colored fabrics, if reactive dyes are used, dyeing quality problems will occur. Although the cause of the problem has a certain relationship with the temperature control (as mentioned above, the temperature rises too fast in the temperature range with high dye uptake), but the more direct cause is the injection method of the dyestuff.
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