Dyeing Machinery Questions and Answers

Answer: A

Correct answer: the mass of liquor to that of the goods

A liquor ratio of 10:1 means ten kilograms of liquor for every kilogram of goods. It governs the water, the steam to heat that water, the salt and chemicals dosed in proportion to it, and the effluent volume - so the whole development of dyeing machinery has been towards lower ratios, from 20:1 on an old winch to 5:1 or below on a modern jet.

Answer: B

Both are true and the reason gives the arithmetic: halving the ratio halves the water and roughly halves the heating load, which is why machine makers have pushed ratios steadily down. Chemical costs fall in proportion as well.

Answer: C

Eight times two hundred kilograms is sixteen hundred kilograms of water, which is about sixteen hundred litres. The ratio is what turns a machine load into a water and chemical requirement. Every recipe is scaled from it.

Answer: D

Correct answer: A-2, B-4, C-1, D-3

Four machines and four presentations of the goods. A winch moves fabric in rope form over an overhead reel. A jigger passes fabric open width from one roll to the other through a shallow trough. A package machine dyes yarn wound on perforated cones or cheeses. A beam machine dyes fabric wound on a perforated beam. The form of the substrate is what decides the machine, as the last item in this topic says.

Answer: A

The fabric passes through a shallow trough of liquor between each winding, giving a very low liquor ratio. It suits fabrics that must not be creased but tends to give end to end shade variation. Its liquor ratio is among the lowest of any machine.

Answer: B

Both are true and the reason gives the mechanism: dye exhausts as the run proceeds, so each end sees a different liquor concentration and the difference shows as tailing along the piece. Careful dye selection reduces the effect.

Answer: C

Correct answer: 1 and 2 only

Statements 1 and 2 are correct: the winch handles fabric in rope form and works at a high liquor ratio, often 20:1 or more. Statement 3 is the opposite of the truth - rope form is exactly what creases fabric, so a crease-prone material such as a smooth polyester or a satin needs an open-width machine like a jigger or a beam.

Answer: D

The liquor does the transport, so mechanical stress on the fabric is low and the liquor ratio can be kept small. High temperature versions run above the boil under pressure for polyester. The venturi is the heart of the machine.

Answer: A

Correct answer: the ability to dye fabric open width

A jet runs the fabric in rope form; open width is what a jigger or a beam machine offers. The other three are the jet’s genuine advantages: a low liquor ratio and so low water, steam and chemical use, gentle handling because the fabric is carried by the liquor rather than dragged, and vigorous liquor exchange through the cloth from the jet nozzle itself.

Answer: B

Correct answer: the fibre must be above its glass transition

Polyester is highly crystalline and its chains are essentially immobile below the glass transition, so disperse dye cannot diffuse into it at any useful rate. Above about 100 degrees the amorphous regions become mobile and the dye enters, which is why the process is run at 130 degrees under pressure - or at the boil with a carrier, which lowers the transition chemically instead.