Development And Application Of The Overflow Dyeing Machine With Extremely Low Liquor Ratio
Fong's energy-saving and environmentally-friendly Jumboflow high-temperature dyeing machine, featuring a well-proven application technology and advanced design, helps customers achieve ecological and economic benefits.
Mo Yong-sheng, Yang Jun-tao and Li-ye
F
ong's energy-saving and environmentally-friendly Jumboflow high-temperature dyeing
machine, featuring a well-proven application technology and advanced design, helps customers
achieve ecological and economic benefits.
The dyeing industry has been subject to many challenges in the last two decades. Nowadays, overflow dyeing machines are still being widely used in the knitted fabrics segment. The conventional overflow machines consume a large amount of water, electricity, steam and chemicals, which lead to high cost of wastewater treatment and serious environmental pollution. Quality-conscious customers are actively seeking eco-friendly dyeing equipment and processes -- which may be defined as those that have a minimal effect upon the environment -- to improve their corporate social responsibility and competitiveness in the textile sector by reducing input costs.
To cope with this market trend, Hong Kong-based Fong's National Engineering Co. Ltd. has launched its high-temperature dyeing machine, Jumboflow, which allows the lowest liquor ratio of 1:4-5 to run the machine, owing to its optimized structural design. The major design parameters of this new series machine are shown in Table 1.
Table 1: Design parameters of Jumboflow high-temperature dyeing machine series
Jumboflow high-temperature dyeing machine
Machine Features
Dyebath Buffer: The dyebath buffer should be of a size that ensures the main pump runs properly without cavitation while the water is fully flooded. In addition, the path of the dye liquid should be short and smooth. This helps the flow return of dye liquor back to the dyebath buffer within the shortest time to achieve a low liquor ratio and separate dye liquid from the fabric. Normally, after one to two cycles, the concentration of liquor on the fabrics would be the same as that of liquor in the water collector.
Dosing System: Dosing speed is controlled by variation of the modulation valve. Normally, there are two types of dosing curve: linear and progressive. Fong's typically applies 0-percent linear curve for dosing dyestuff and salt, and 50-percent progressive curve for dosing sodium carbonate. Fresh dye liquor is fed into the dyebath buffer at its lower part, which is driven by the second circulation pump to mix with liquor inside, and then delivered by the main pump to spray onto the fabrics through nozzles. This dosing system not only reduces the dosing time, but also increases levelness of dyeing dramatically.
Multi-function Stock Tank (MST): The stock tank is in the capacity of a 1:5 liquor ratio and is used to prepare liquid for the next step. Chemicals can be delivered into the tank and heated to target temperature. This helps to reduce the total process time remarkably.
Rinsing System: Fong's Multi Saving Rinsing System (MSR) allows the dyeing process to carry out cooling and rinsing simultaneously. For those dyehouses that do not recycle cooling water, MSR reuses the cooling water discharged from the heat exchanger directly and carries it back to the machine for rinsing. This system eliminates the direct discharge of the cooling water and, hence, considerably reduces water consumption.
In order to improve the traditional intermittent rinsing process, reduce the rinsing process time and increase the rinsing efficiency, Fong's developed the AIR+ Advanced Intelligent Rinsing System. With the aid of a flowmeter and modulation valve, the flow rate of filling water can be controlled automatically. The greater the flow rate is, the better the rinsing performance and the shorter the process time would be, but the water consumption would be high. In practice, the water consumption and process time would be optimum at a flow rate to fabric weight ratio of 1:1 -- for example, 280 liters per minute (L/min) flow rate: loading 280 kg. Rinsing efficiency also can be increased by controlling the water level below the storage chamber so that the fabric and dye liquor are separated. At the same time, the water level is controlled by discharge rate. During the rinsing process, the conductivity of the electrolytes in the dye liquor, measured in parts per million (ppm) is actively monitored. The rinsing process continues until it arrives at a particular total dissolved solids (TDS) value -- the standard is 2,000 ppm = 2 grams per liter of sodium sulfate (Na2SO4). As the usage of the alkaline is directly proportional to the TDS value and the TDS value is also proportional to the usage of acetic acid (HAc), according to the Equivalent Weight Principle, it not only ensures the performance of neutralization by HAc, but also reduces water consumption and process time.
Fabric Circulation System: The following features help minimize any possible pressure that may affect the fabrics' dimensional stability in the kier:
Application Of Rapid Dyeing Process
Scouring and bleaching, dyeing, and rinsing steps for dyeing cotton with reactive dye are presented below:
Table 2: Cost Comparison
Conclusion
As is shown in Steps 1-3 of the trial and cost comparison shown in Table 2, the short dyeing process of Fong's Jumboflow high-temperature dyeing machine is able to help dyehouses dramatically lower production costs as well as reduce energy consumption and effluent discharge -- which, by all accounts, results in substantial ecological and economic benefits.
Editor's note: Mo Yong-Sheng, Yang Jun-tao and Li-ye are engineers at Fong's National Engineering (Shenzhen) Co. Ltd.'s Application Technology Center.
References:
[1] Cheng Rongqi, Wetting Property and Dissolvability Treatment of Water Soluble Dye [J], Printing and Dyeing, 2003, 29 (5): 44-45; 200, 29 (6): 43-47 .
[2] Cheng Rongqi, Analyzing the Ten Parameter of Reactive Dye Dyeing Property [J], Printing and Dyeing, 2005, 31 (13): 45-49; 2005, 31 (14): 45-49 .
February 16, 2010
The dyeing industry has been subject to many challenges in the last two decades. Nowadays, overflow dyeing machines are still being widely used in the knitted fabrics segment. The conventional overflow machines consume a large amount of water, electricity, steam and chemicals, which lead to high cost of wastewater treatment and serious environmental pollution. Quality-conscious customers are actively seeking eco-friendly dyeing equipment and processes -- which may be defined as those that have a minimal effect upon the environment -- to improve their corporate social responsibility and competitiveness in the textile sector by reducing input costs.
To cope with this market trend, Hong Kong-based Fong's National Engineering Co. Ltd. has launched its high-temperature dyeing machine, Jumboflow, which allows the lowest liquor ratio of 1:4-5 to run the machine, owing to its optimized structural design. The major design parameters of this new series machine are shown in Table 1.
Table 1: Design parameters of Jumboflow high-temperature dyeing machine series
Jumboflow high-temperature dyeing machine
Machine Features
Dyebath Buffer: The dyebath buffer should be of a size that ensures the main pump runs properly without cavitation while the water is fully flooded. In addition, the path of the dye liquid should be short and smooth. This helps the flow return of dye liquor back to the dyebath buffer within the shortest time to achieve a low liquor ratio and separate dye liquid from the fabric. Normally, after one to two cycles, the concentration of liquor on the fabrics would be the same as that of liquor in the water collector.
Dosing System: Dosing speed is controlled by variation of the modulation valve. Normally, there are two types of dosing curve: linear and progressive. Fong's typically applies 0-percent linear curve for dosing dyestuff and salt, and 50-percent progressive curve for dosing sodium carbonate. Fresh dye liquor is fed into the dyebath buffer at its lower part, which is driven by the second circulation pump to mix with liquor inside, and then delivered by the main pump to spray onto the fabrics through nozzles. This dosing system not only reduces the dosing time, but also increases levelness of dyeing dramatically.
Multi-function Stock Tank (MST): The stock tank is in the capacity of a 1:5 liquor ratio and is used to prepare liquid for the next step. Chemicals can be delivered into the tank and heated to target temperature. This helps to reduce the total process time remarkably.
Rinsing System: Fong's Multi Saving Rinsing System (MSR) allows the dyeing process to carry out cooling and rinsing simultaneously. For those dyehouses that do not recycle cooling water, MSR reuses the cooling water discharged from the heat exchanger directly and carries it back to the machine for rinsing. This system eliminates the direct discharge of the cooling water and, hence, considerably reduces water consumption.
In order to improve the traditional intermittent rinsing process, reduce the rinsing process time and increase the rinsing efficiency, Fong's developed the AIR+ Advanced Intelligent Rinsing System. With the aid of a flowmeter and modulation valve, the flow rate of filling water can be controlled automatically. The greater the flow rate is, the better the rinsing performance and the shorter the process time would be, but the water consumption would be high. In practice, the water consumption and process time would be optimum at a flow rate to fabric weight ratio of 1:1 -- for example, 280 liters per minute (L/min) flow rate: loading 280 kg. Rinsing efficiency also can be increased by controlling the water level below the storage chamber so that the fabric and dye liquor are separated. At the same time, the water level is controlled by discharge rate. During the rinsing process, the conductivity of the electrolytes in the dye liquor, measured in parts per million (ppm) is actively monitored. The rinsing process continues until it arrives at a particular total dissolved solids (TDS) value -- the standard is 2,000 ppm = 2 grams per liter of sodium sulfate (Na2SO4). As the usage of the alkaline is directly proportional to the TDS value and the TDS value is also proportional to the usage of acetic acid (HAc), according to the Equivalent Weight Principle, it not only ensures the performance of neutralization by HAc, but also reduces water consumption and process time.
Fabric Circulation System: The following features help minimize any possible pressure that may affect the fabrics' dimensional stability in the kier:
- The lifter reel is made of stainless steel, and the storage chamber is equipped with Teflon® bars to reduce friction.
- For models with more than one lifter reel, each reel is controlled by an independent motor and frequency inverter. Consequently, even if one reel is down, the others can still run normally.
- High nozzle pressure and running speed assure proper cycle time of all types of fabrics.
- The plaiter operates at the same rate as the reel, laying the fabrics into the chamber evenly.
- The variable loading (VL) storage chamber changes its profile to accommodate a large variety of fabric types, from light- to heavyweight materials.
Application Of Rapid Dyeing Process
Scouring and bleaching, dyeing, and rinsing steps for dyeing cotton with reactive dye are presented below:
Table 2: Cost Comparison
Conclusion
As is shown in Steps 1-3 of the trial and cost comparison shown in Table 2, the short dyeing process of Fong's Jumboflow high-temperature dyeing machine is able to help dyehouses dramatically lower production costs as well as reduce energy consumption and effluent discharge -- which, by all accounts, results in substantial ecological and economic benefits.
Editor's note: Mo Yong-Sheng, Yang Jun-tao and Li-ye are engineers at Fong's National Engineering (Shenzhen) Co. Ltd.'s Application Technology Center.
References:
[1] Cheng Rongqi, Wetting Property and Dissolvability Treatment of Water Soluble Dye [J], Printing and Dyeing, 2003, 29 (5): 44-45; 200, 29 (6): 43-47 .
[2] Cheng Rongqi, Analyzing the Ten Parameter of Reactive Dye Dyeing Property [J], Printing and Dyeing, 2005, 31 (13): 45-49; 2005, 31 (14): 45-49 .
February 16, 2010
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