Important Definitions

Carding ratio: It is ratio between the surface speed of cylinder and surface speed of worker roller.

Carding efficiency:   

[(Surface speed of cylinder – surface speed of worker roller)/Surface speed of cylinder]x 100

 

Card pinning: the process by which pins are set on different rollers in the card.

Clock length: the length of the feed material which is fed per one revolution of clock pointer is called clock length.

Dollop weight: the weight of the feed that is fed per one revolution of the clock pointer is called dollop weight.




For Better understanding of the different rollers of Jute Carding Machine visit the click link below

JUTE CARDING MACHINE

Jute Carding Machines

Types of carding machines according to cylinder direction.

1. Up striking: In this card the material moves over the cylinder

2. Down striking: In this card the material moves under the cylinder

Types of carding machines according to path of jute.

1. Half Circular: Here the jute travels half the circle of the cylinder.

2. Full Circular: Here the jute travels the entire circle of the cylinder.

Breaker Card

Principle of Breaker Card:  It is a down striking and half circular carding machine. Its feed is at one side of the machine and delivery is on the opposite side.

Working regions:

• Combing action occurs between stripper and worker roller.
• Carding action occurs between cylinder and worker roller.
• Opening spreading ocurrs between shell and pin feed roller.

Speed of rollers:

Cylinder: 2400 – 2700 feet per minute

Feed roller: 9 – 14 feet per minutes

Worker: 35 – 50 feet per minutes

Stripper: 300 – 500 feet per minutes

Doffer: 75 – 95 feet per minutes

Delivery roller: 150 – 200 feet per minutes

Finisher Card

Principle of Breaker Card:  It is a down striking and full circular carding machine. Its feed and delivery is on the same side of the machine.

Working regions:

• Combing action occurs between stripper and worker roller.
• Carding action occurs between cylinder and worker roller.
• Opening spreading occurs between cylinder and pin feed roller. 

Speed of rollers:

Cylinder: 2400 – 2800 feet per minute

Feed roller: 10 – 15 feet per minutes

Worker: 30 – 40 feet per minutes

Stripper: 300 – 500 feet per minutes

Doffer: 75 – 100 feet per minutes

Delivery roller: 150 – 200 feet per minutes

Jute Carding and its faults

Carding is the process by which long strikes of jute fibres, while passing through high speed pinned rollers, are broken down into an entangled mass and delivered in ribbon form of uniform weight per unit length.

Objects of Carding

• To break down the long strikes of jute and split up
• To individualize the fibre
• To reduce the fibres weight per unit length
• To make sliver of uniform weight per unit length
• To mix the quantities of jute fibre

Cause of excessive droppings in Jute Breaker Card

1. Hard and specky jute fibre.
2. improper emulsion application
3. improper speed ratio of different rollers
4. faulty roller pins
5. more work load on pin
6. high or low moisture regain
7. if any roller is eccentric

Cause of excessive Sliver wastage in Jute Breaker Card

1. more moisture regain
2. faulty roller setting
3. faulty pin
4. jam or lapping due to faulty drawing
5. faulty auto stop motion
6. frequent quality change
7. operation negligency

O.D Batch Mixer, Softener Machine and Spreader Machine

How to make Emulsions? (O.D Batch Mixer)

Procedure of emulsion preparation

• First emulsifier and equal quantity of mineral oil are place in the mixing tank and mixed until a jelly like substance is formed.
• Then the remaining oil is added and slowly heated and mixed for 35 minutes
• Then required amount of water is add and mixed for about 20 minutes until required form is achieved.
• After that the emulsion is transferred to the reserve tank and kept there for 20 minutes.
• Then it is transferred to the softener or spreader machines.

Softener Machine

These machines consist of 24 to 64 pairs of rollers and these are spirally fluted and jute goes through them. When the jute passes one third of the rollers then the emulsion is added with the spray. Then through the delivery rollers the jute is passed on to the delivery sheet.

Machine specification

Length: 16 feet

Motor rpm: 715 revolutions per minute

Surface speed of feed roller: 83.84 inch per minute

Surface speed of fluted roller: 93.86 inch per minute

Surface speed of delivery roller: 103.4 inch per minute

Spreader Machine

The jute fibres first enter through the feed rollers on to the slow chain. This contains pins or grill bars which have a combing action on the jute. Then the jute moves to the fast chain which moves 10 to 12 times faster than the slow chain. Here combing action occurs and also due to the speed variations the fibres get a draft of 10. Then the jute moves to the conductor plate where it is sprayed with emulsion and at last it is rolled up by the roll former.

Faults of emulsion

 

Creaming: When an emulsion is prepared it is not possible to make all drops exactly same size. The larger droplets move to the surface because they have less density than water. These droplets cause uneven distribution of water and form a layer on the surface and causes uneven distribution of emulsion. This defect is called creaming. This defect increase yarn breakage during spinning.

           

Causes of creaming

·      Improper oil selection

·      Not accurate mixing ratio of oil, water and emulsifier

·      Bad agitation of the mixture

Remedy to avoid creaming

·      Using slow running paddles to stir the mixture, thus the droplet size can be kept small

·      Using oil of high specific gravity

·      Emulsion should not be stored for long time

Breaking: Sometimes the mixture is not uniform and so in some places it is dense and in others it is light. The defect is called breaking.

It is caused by faulty stirring equipment. 

It can be avoided by high speed agitation.

Why fish oil and vegetable oil is not use in making emulsion?

Drawbacks of fish oil

• It is very costly
• It has a very bad smell
• If the percentage of fish oil is more then it will lead to combustion of fire

Drawbacks of vegetable oil

• In comparison to mineral oil, it is very costly
• It allows dirt and bust to lap around the rollers and thus it jams the rollers
• It causes build up of static electricity between the fibres and rollers which causes the fibres to stick to the rollers