Mainly as a result of the oil crisis in the mid-1970s the textile industry looked at
various possible methods of reducing energy costs. The dyeing and printing of carpets
requires considerable energy input, usually in the form of steam, and this is largely due
to the substantial amount of liquor applied to the substrate (liquor pick-up may be
300–400%) which must then be heated to 100 °C. Attention was therefore turned to
ways of reducing the water content of the carpet prior to steaming.
One approach to this problem, which has also been applied to textile dyeing and
finishing, is to use foam as the fluid medium for dye and chemical application. A
typical foam for carpet coloration may consist of 10–20 volumes of air to one of water,
and it has the flow properties of a viscous liquid. The first successful use of foam to
colour carpets was for continuous dyeing, followed by multicolour foam printing. In
1980 Stork introduced a modified rotary-screen printer for textiles using foamed print
pastes, and both Mitter and Zimmer produced machines for foam-printing carpet.
In the Mitter printer the print liquor, containing special surfactants, is passed
through a microprocessor-controlled foam generator (either a so-called marshmallow
pump or a static mixer unit) and the foam is fed through the rotary screen from a slot
applicator, not unlike the Zimmer Hydroslot squeegee. The Zimmer system utilises the
Variopress squeegee placed inside the rotary screen and the foam is fed continuously by
the gear pump system through the applicator slot.
Foam printing has not been without its problems and, in the USA at least, foam
applicators have been largely replaced by the simpler spray jet application systems.
Both foam and spray systems allow the liquor pick-up on the carpet to be reduced to
about 150%, which not only reduces steam consumption but also allows faster running
speeds (up to 30 m min–1).
various possible methods of reducing energy costs. The dyeing and printing of carpets
requires considerable energy input, usually in the form of steam, and this is largely due
to the substantial amount of liquor applied to the substrate (liquor pick-up may be
300–400%) which must then be heated to 100 °C. Attention was therefore turned to
ways of reducing the water content of the carpet prior to steaming.
One approach to this problem, which has also been applied to textile dyeing and
finishing, is to use foam as the fluid medium for dye and chemical application. A
typical foam for carpet coloration may consist of 10–20 volumes of air to one of water,
and it has the flow properties of a viscous liquid. The first successful use of foam to
colour carpets was for continuous dyeing, followed by multicolour foam printing. In
1980 Stork introduced a modified rotary-screen printer for textiles using foamed print
pastes, and both Mitter and Zimmer produced machines for foam-printing carpet.
In the Mitter printer the print liquor, containing special surfactants, is passed
through a microprocessor-controlled foam generator (either a so-called marshmallow
pump or a static mixer unit) and the foam is fed through the rotary screen from a slot
applicator, not unlike the Zimmer Hydroslot squeegee. The Zimmer system utilises the
Variopress squeegee placed inside the rotary screen and the foam is fed continuously by
the gear pump system through the applicator slot.
Foam printing has not been without its problems and, in the USA at least, foam
applicators have been largely replaced by the simpler spray jet application systems.
Both foam and spray systems allow the liquor pick-up on the carpet to be reduced to
about 150%, which not only reduces steam consumption but also allows faster running
speeds (up to 30 m min–1).
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