Textile bleaching Machine is one of the stages in the manufacture of textiles. All raw textile materials, when they are in natural form, are known as ‘Greige’ material (pronounced grey-sh). This Greige material will have its natural color, odor and impurities that are not suitable for clothing materials. Not only the natural impurities will remain on the Greige material but also the add-ons that were made during its cultivation, growth and manufacture in the form of pesticides, fungicides, worm killers, sizes, lubricants, etc. The removal of these natural coloring matters and add-ons during the previous state of manufacturing is called scouring and bleaching.
Bleaching Machine is consist of the following unit,
- Entry J-box
- Washing Tank ( Pre-Washer)
- Chemical Tank
- Dipset System
- Steamer Feedin
- Steamer Continue
- Steamer Feedout
- Washing Tank ( Post Washer)
- Dry cylinder
- Exit J-box
- Water System
- Steamer system (Heating System)
- Pneumatic System
- Dozing System
- Operating System
- Vacuum System
This unit is used to unroll the fabric and store it in to the Scray to run the machine continuously. It is consist of a motor controlled by the inverter, compensator and expender rollers.
The speed of the motor can be controlled by the inverter and compensator is used to synchronize this unit with the machine. During the running of machine, press the push button “J-box filling” the speed of J-box drives is increased and J-box will be filled. When we depress the push button “J-box filling”, the speed of J-box down to stoppage.
If the minimal fabric contents are falling, the speed of the J-box drive increases the machine speed with the influence of the compensator and breaking roll is released.
We can also see the speed of J-box on the meter at operating panel.
This is used to wash the fabric. We put the fabric into washing tank from the scray. Each washing tank consist of the two upper roller motor, one squeezer motor, two expender roller and one compensator. Fabric is transferred through the Padder and rollers to the next washing tank.
In this tank we have a heating option when we active the heating system then to control the temperature of the tank we have a temperature sensor that shows the actual temperature value on Monitor. We have the pneumatic valve for heating system which is controlled by PLC.
The fabric comes into chemical tank from the washing tank. In this tank the fabric is treated with the chemical as per recipe. It has a Padder motor and upper roller motor.
Both the motors are driven by the separate inverter.
This is a tank in which all the required chemicals mix together with water and transfer it to the chemical tank by the help of circulation pump. The circulation pump works when the Dipset tank filled with the required level of chemical.
According to the recipe the automatic water filling system transfer the required quantity of water in to the Dipset tank. The level of the tank controlled and detected by the pneumatic pressure switches with very few amount of air pressure (15~ 50mbar) and these pressure switches provides the signal to the PLC.
Each bowl can contain the specific quantity of liquid. When the bowl are filled it drop the chemical in to the Dipset tank at that time the proximity sensor sense the movement of bowl and transmit the Pulse signal to PLC.
Steamer is a unit of the machine and can be used by three ways. I. Feed-in steamer ii. Continue Steamer and iii. Feed-out Steamer
- Feed-in Steamer:
In this steamer the drive of group A are enabled (feed in group) till the platter drive inside steamer). The remaining fabric on conveyor is pulled out by pressing the push button inching. The drive group B (feed out group) run in inching –mode with basic speed, as long as the push – button is pressed, but not longer than 15 seconds each time.
It has two feedin motors, one platter motor and six upper roller motors. All of the motors are controlled by the inverters. To synchronize the platter for the machine with the help of compensator POT.
- Continue Steamer:
In this machine mode the chosen drives run simultaneously, the conveyor is filled continuously in which the fabric contents kept constant on the conveyor by means of regulator roller.
The movement of the roller influences the speed of the drives (feed out group B). The speed relationship is shown on the configuration side.
A selected manual speed control in the configuration side will the regulator roller remain without influence and the speed of the drives feeding out the fabric can be influenced with a specification value of 90% to 110%.
- Feed-out Steamer:
In this machine mode the chosen drives of the feed out group B exclusively run. The fabric is pulled out from the conveyor.
Mode washing with out steamer, all function of the steamer is in this mode shut down. The fabric way must be changed.
It is possibly, of continue the machine run (continue) to switch to feed out while without this the machine stops. By the switchover during the machine run the move group is stopped automatically.
Post Washing Tank:
Fabric comes in these tanks from the steamer. Each tank consist of a Padder with compensator, two expender rollers and two upper rollers motors. These tanks also use for the washing purpose and last tank is used for the neutralizing of fabric.
It is used to dry the fabric. There are three dry cylinder units and each unit consist if 8 cylinders and controller by one inverter. Each cylinder rotates by separate motor. It is synchronized by the compensator POT.
The last two cylinders are used to cool down the fabric.
This unit consists of a motor, compensator and expender roller. It is also used to store the fabric in the J-box to run the machine continuously.
Pressing the push-button batcher stop the batcher drive is slowed down and stopped. If the drive has stopped, the dock-change can be done. The J-box is filled with the fabric at this time. The compensator roller fallen down to lower position.
This unit is used to wind the fabric on the A frame batcher. It is consist of a motor controlled by the inverter, compensator POT & expender roller.
If there is a fabric in exit J-box the speed of the winder can be increased up to double the speed of the machine. To control the speed of the winder there are buttons that transmit the signal to the PLC which commands the inverter to increase or decrease the speed of the winder.
In this system we have water flow counter in main water inlet pipe. The quantity of water is controlled by the pneumatic valve that can be controlled from monitor.
We also have a pneumatic valve on each tank water inlet pipe except in tank No. 3, 7 & 8. In these tanks we have a motorized controlled valve on water inlet pipe. These motorized valves transfer the desire quantity of water in to the tank which is counted by the water flow counter. These motorize valve having the 220 Vac motor which can be run on both direction by which the valve can be opened or closed and controlled by the PLC.
The flow counters are worked on 24Vdc system and provides the signal to the PLC and PLC controls the motorized valve.
Steamer Heating System
There are two inlet paths for steam. One steam inlet is used for heating the water at the bottom of the steamer and other is used for roof heating of steamer. There are a separate bypass valve and controlled valve.
Controlled valve is working on the principle of PIV system. There is IP controller separate valve for it and PLC command the valve to operate. The position of the valve detected by the feedback POT and displayed on the screen.
The temperature of the steamer is sensed by 6 temperature sensors (PT-100) in which 4 are installed at the bottom, 1 is installed on pre-steamer and last is on steamer center.
The PT-100 provides the signal to the PLC analog card and Plc displays the temperature of the steamer on the screen.
Pneumatic System :
There is a pneumatic panel in the machine by which the air for the different parts of the machine is provided. It has many valve block which controlled by PLC and use 24Vdc as input. The pneumatic valve operating the different parts of the machine such as Padder pressure, Steam Valve open / close, Clutch, Pressure switch, compensator piston and etc.
There are dosing pump for adding the chemical is feeded to the machine. The chemical added depending on the makeup water volume. You can select the dosing take place in the machine, status, setup and production on the given recipe.
There is a pneumatic pump which is powered up by 24Vdc. There are level sensors installed on the tank by which it takes the chemical. If incase that the tank is empty the level switch generate the pulse signal to the PLC and display the error on the screen.
Operating system is used to run the machine. It is basically a graphical user interface program which is installed on the Personal Computer and name as Basis operating System. To perform the different operation it is necessary switch the machine to different machine status. There some machine status such as:
- Standby mode:
No function all machine elements are inactive.
- Production mode:
Production with machine.
- Setup mode
Preparation for production, charging and heating of the machine.
- Discharge mode:
All parts of the machine is being discharged.
- Dosing, reverse mode:
The machine can be run in reverse mode with only one motor. If you select reverse all drives will become deselected.
- Master motor system:
When master drives are being powered up or down the associative auxiliary drives are being powered up or down as well. Auxiliary drive can only be operated together with the associative master drive. Drives which are connected to electrical power are displayed as green field elements are being the drives has been enabling.
- Vacuum System:
There is a vacuum drive on the machine. It has a motor with vacuum gear which controlled by inverter and feedback by pressure transducer. It is also have a temperature probe, separator pump and level sensors.
The vacuum pump can be operated in regulated and controlled mode. In the controlled mode, a fixed pump speed as a percentage of the maximum speed is given. The pump capacity remains constant, irrespective of the achieved vacuum. In the regulated mode, the pump is triggered by a variance comparison between the given vacuum and the measured actual vacuum. The vacuum valve is specified in mbar. The pump capacity may change in order to keep the actual value for the vacuum at a constant level.
The set point of vacuum is entered in the recipe. If they switch fashion to automatic mode, then the set point must be indicated in mbar.
Like the other drives, the vacuum pump can be switched on and off by using the corresponding key field.
If the drive has been selected, the vacuum pump starts operation together with the line start-command.
After the outlet group came to a stop or after the vacuum pump was switched off, the latter remains on for another ten minutes in order to allow it to become dry. During this time, the bypass valve for taking in ambient air is open; the pump runs at basic speed rate.
A temperature probe is used to continuously monitor the temperature of the exhaust air. If the temperature exceeds a value of 160oC, the pump speed is reduced to basic speed and the bypass valve opened in order to allow the pump to cool down.
The vacuum pump transports the sucked-off air-water mixture to the separator. There the water is eliminated. Upon reaching the level switch, the filling height in the separator tank is subjected to continuous monitoring. If the maximum filling height is reached, the vacuum pump speed is automatically reduced to basic speed. If, despite of the reduction, the filling height remains at its maximum level over a period of time of 20 seconds, the pump is disconnected. The corresponding warning can be seen on the tableau. The pump can only be re-started after the error was acknowledged and the filling level dropped below its maximum height.