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CHAPTER 12

Dyeing machinery

Dyeing machines come in all shapes and sizes to accommodate the various forms
and quantities of textile materials. In one chapter, it is impossible to provide
exhaustive coverage of this field. Therefore, the most important types of machine,
and their problems, will be at the forefront.

Dyehouse machinery represents a large capital investment. The correct choice
of equipment, and its effective use and maintenance, are important factors
influencing the success of a dyehouse. Modern machines often have programmable
microprocessors for automatic control of the process variables, particularly the
dyeing temperature [1]. This subject is beyond the scope of this book. Equipment
for fabric preparation, and for water removal and drying, will also not be discussed.

12.1 BASIC FEATURES OF BATCH DYEING MACHINES

Textile materials may be dyed at various stages during manufacture. They may be
in the form of raw stock (loose fibre), sliver, top or tow (loosely constituted bands
of parallel fibres or filaments), yarn, fabric or piece, or made-up articles such as
hose or garments. The actual stage at which dyeing occurs in the production cycle
depends on the associated costs, the subsequent processing required and the end-
use of the goods, and on the colour fastness required at each stage. The modern
trend is to delay coloration until as late as possible in the production scheme. This
facilitates rapid response to market trends, as illustrated by the recent popularity of
garment dyeing.

A dyeing machine has a container in which to hold the dye solution and the
goods being dyed. It must be connected to a water supply for filling, and to a drain
for discharge of the exhausted bath and rinsing water after dyeing. The first
requirement for level dyeing is that all portions of the goods have equal access to
the dye solution. The machine must allow uniform circulation of the dye liquor
through the stationary material, or movement of the goods through the stationary
dye bath, or, preferably, circulation of both the bath and the material.

In modern dyeing machines, the surfaces and parts in contact with the dye
liquor and the textile are invariably made from stainless steel. This has high
resistance to wear and corrosion. Even then, there may be problems when using

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