Drying and gas or vapor contact with solids – Process – Mechanical liquid removal
Reexamination Certificate
1999-08-11
2001-01-16
Wilson, Pamela (Department: 3749)
Drying and gas or vapor contact with solids
Process
Mechanical liquid removal
C034S397000, C034S398000, C034S438000, C034S459000, C034S203000, C034S207000, C034S216000, C026S018500, C026S018600
Reexamination Certificate
active
06173507
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
When knitted fabric is produced and is bleached, dyed or otherwise treated it generally emerges in tubular form, twisted like a rope, and in a wet condition. Residual shrinkage in the fabric for manufacture of garments must be controlled within acceptable limits. Tumble dryers are popular in homes and they present a difficult challenge to residual shrinkage in knitted garments. Washing and tumble drying of knitted garments at home normally eliminates about ninety-eight percent (98%) of all potential knit shrinkage, yielding two percent (2%) of residual shrinkage. So if a culprit knitted fabric has more than two percent (2%) of residual shrinkage, trouble brews. After a garment is manufactured from the culprit fabric, when a consumer washes it and puts it into his or her tumble dryer, a moment of truth arrives. The tumble dryer further shrinks the garment down to two percent (2%) residual shrinkage: The garment reduces in size and is apt to fit its wearer like a sausage in its casing.
A garment manufacturer can compensate for anticipated excess residual shrinkage by oversizing garments so as to be ready for tumble dryer shrinkage. But an oversized garment then does not fit properly before it is washed and tumble dried. Further the oversized garment frequently becomes distorted because its shrinkage cannot be controlled uniformly throughout.
In producing and treating wet knitted fabrics many attempts have been made to control residual shrinkage in garments made therefrom by duplicating conditions of the tumble dryer in production of the fabric. Yet action of the tumble dryer on a garment, which in essence is a short piece of the fabric, differs from action on a long web of the fabric which travels continuously through an industrial knitting and/or converting mill. Even though prior industrial dryers have improved, in response to the tumble dryer challenge, the prior art industrial dryers still do not reduce residual shrinkage as much as a consumer's tumble dryer at home does on finished garments.
Another approach to control of residual shrinkage in the garment comprises compacting the fabric when it is almost dry. However such strategic almost-dry compacting can be difficult to perform, particularly when significant shrinkage has to be achieved. When performing the strategic almost-dry compacting the fabric has to be handled very carefully to prevent fall-out of the shrinkage prior to cutting.
OBJECTS AND SUMMARY OF THE INVENTION
The foregoing disadvantages of prior approaches to control residual shrinkage of knitted fabrics are substantially overcome by the present invention. A pair of compactors is separated each from the other by a special dryer that itself achieves a very significant shrinkage through shortening loops of the knit fabric. The fabric moves through the special dryer while in a relaxed tension-free condition to allow the loops of the fabric knits to shorten by coming together and thereby reduce very substantially the fabric residual shrinkage. Waving of the fabric in the dryer also contributes to shortening loops of the fabric knits. The compactors preferably comprise first one with multiple belts providing shrinkage of relatively wet fabric prior to its entry into the special dryer and after the fabric is discharged from the special dryer it is delivered to another compactor usually of a double-roll type for accurate final compaction. Thus the knitted fabric is provided with an acceptable residual shrinkage, less than two percent (2%), and is ready for garment cutting or other finishing that may be appropriate. The problem of unacceptable residual shrinkage, over two percent (2%), in the knitted fabric has been eliminated. Garments made from the knitted fabric become tumble-dryer shrinkage proof.
Accordingly one object of the present invention is to control within acceptable limits residual shrinkage in garments made from knitted fabrics.
A further object of the present invention is to simulate in an industrial knitting mill action of a home tumble dryer for pre-shrinking knitted fabrics, or other similar fabrics, subject to a high degree of shrinkage.
A still further object of the present invention is to employ to their best advantage commercially available and reliable equipment items, along with the special dryer, which all cooperate in an optimal sequence so as to achieve desired control of residual shrinkage in garments made from knitted fabrics.
A still further object of the present invention is to conclude the finishing process with improved accuracy and reliability of residual shrinkage of the knitted fabrics.
A still further object of the present invention is to provide a finishing line of equipment that is safe, efficient, easy to operate and repair, and well suited to its intended task.
The foregoing and other objects and advantages of the present invention will appear more clearly hereinafter.
In accordance with the present invention there is provided an arrangement of apparatuses and a related method.
REFERENCES:
patent: 3007223 (1961-11-01), Wehrmann
patent: 4363161 (1982-12-01), Catallo
patent: 4622728 (1986-11-01), Bumuller et al.
patent: 4872383 (1989-10-01), Niwa et al.
Baxley Charles E.
Wilson Pamela
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