After completing the dyeing process from the dyeing machine then the fabrics are ready for dewatering. This is the process to remove the water from the fabric completely by squeezing. De-watering machine plays an important role in knit finishing section of the knit fabrics. Dewatering machine or Squeezer is used for reducing water from the wet fabric. It reduces the water content of the fabric. This is the main function of the de-watering machine. But here also control the some important factor of the fabric quality.
The basic function of the dewatering machine are:
- To remove the water from the fabric.
- To control the width of the fabric.
- To control the length of the fabric.
- To control the spirality of the fabric.
- To control the grain line of the fabric.
- To control the over feeding system.
For details you can read: Dewatering Machine: Functions, Process Sequence and Operational Parameters
Dewatering Machine Parts and Their Functions:
The dewatering machine is similar to extractor padder, with some additional attachments which have extra facilities. There is a magnetic sensor which senses the twist of fabric and its direction,which causes to turb the turn table in opposite direction to remove the twist automatically. The tubular fabric is ballooned by the compressed air before passing through the nip, so all loops are stretched very uniformly and in flat form water is removed.
De-watering machine has different parts and every single part has specific functions. Followings are de-watering machine parts name with their functions.
1. Hand Wheel: It is a manual process. It is used for guide the spreader.
2. Turn Tube: Fabric rotation is controlled by turn tube. It also helps in fabric feeding to the spreader.
3. Squeezing Roller: It is the main part of the de-watering machine. Water of the wet fabric is squeezed by the squeezing roller.
4. Guide Wheel: Guide wheel helps to feed the fabric into the squeezing roller.
5. Spreader: When fabric is dye in a dyeing machine it found in rope form. After dyeing, when dyed fabric is put in basket it also remains in rope position. By spreader we can open fabric from the rope position. It can be spread and compressed in width direction by its hydraulic cylinder.
6. Security Shield: Security shield is an emergency switch settled with a plastic board very near to the padder. When it is close to the padder it is on and when it is pulled back then it is off. In case a big knot is going to pass the padder then it immediately pulls back the board to stop the machine. It is an automatic system to ensure the security of the padder. It helps to avoid any types of incidence.
7. Air Injection Switch: It pushes air into fabric to turn it to ballooning form. It helps to turn the rope form fabric into open form.
8. Photocell: Photocell is an auto sensor which control air injection.
During de-watering process, softener is applying to the knit fabric. Also, various types of chemicals can be applied on the fabric by this de-watering machine. It is important to maintain uniform tension during operation otherwise GSM of the can be vary in different parts of the fabric.
Special Features of Dewatering Machine:
- Single squeeze roller and single padder present.
- One for squeezing and other for applying softener finished.
- Above 80% water can be removed
- Maximum 60 inch diameter can be extended.
- Softener tank present.
Maintenance During Operation:
- Proper balloon form by compressor air otherwise crease mark appears.
- Padder contract point adjusts perfectly according to the fabric construction otherwise accurate water will not remove.
- Albatros must be clean every one or two hours later.
Machine Specification of De-watering Machine:
- Brand Name: Santex ag
- Company: Santex ag
- Origin: Switzerland
- Model: CH-9555, Tobel
- Overfeed Range: -5% to +10%
- Year of Manufacture: 1998
- Type: Santa stretch Plus-140
- Max Working Speed: 80 m/min
- Maxm width capacity: 112 cm
- Normal working Speed: 40~ 60 m/min
- Maximum padder pressure: 40 PSI
- Used Utilities: Water electricity, Compressed air
Parameters Used for Different Constructed Fabric:
For Cotton Fabric:
|Fabric Type||Overfeed %||Stretch %||Folder Tension||Machine Speed (m/min)|
|Single Jersey||+8% to +10%||2”-3”||-14% to -15%||60 -65|
|Single Lacoste||+4% to +5%||2”-4”||-17% to -18%||60 -65|
|Polo Pique||+3% to +4%||3”-4”||-17% to -18%||60 -65|
|Interlock||-1.5% to +2.5%||8”-10”||-18% to -20%||55 -60|
|Rib||+4.5% to +5%||—||-14% to -15.5%||60 -65|
For Polyester Fabric:
|Fabric Type||Overfeed %||Stretch %||Folder Tension||Machine Speed(m/min)|
|Single Jersey||+3% to +4%||2”-3”||-16% to -18%||55 -60|
|Single Lacoste||+4% to +5%||3”-4”||-18% to -20%||55 -60|
|Polo Pique||+1% to +2%||3”-4”||-17% to -18%||55 -60|
|Interlock||-3% to -4.5%||5”-6”||-18% to -20%||55 -60|
|Rib||+3% to +4%||—||-14% to -16%||60 -65|
N.B: This Data’s are varied depending upon the Gray G.S.M and Finished G.S.M and also on the dia of the fabric. All this parameters are suitable for G.G.S.M range 140~160 to get Fin. G.S.M 170~185 without Lycra Fabric. All This data`s are practiced in mills which may varied factory to factory.
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Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. He is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.