Note: Descriptions are shown in the official language in which they were submitted.
~3~03~
_MACHINE FOR AND METHOD OF
PROD~CING TREATING OR FINISHING A FABRIC
The present invention relates to a machine for
producing, treating or finishing fabrics in the piece.
At the present time, in a textile finishing process,
it is usually necessary as the final step, or one of the
final steps, to dry the fabric. This is generally done by
feeding the fabric progressively through a drying oven.
Extreme care must be taken in handling the fabric at this
time since any distortion produced in the fabric may be
permanently set into the fabric by the drying process.
For example, if the fabric is subjected to undue stress in
the lengthwise direction of the fabric this results in neck-
ing which in turn results in a reduction of the width of
the fabric. To prevent, or at least reduce the risk of,
this happening the material is held on both longitudinal
edges at relatively closely spaced points as it passes
through the oven. Such a machine, which is called a stenter,
is complicated and expensive.
In other processes such as the coating of fabrics,
for example, with a gellable or curable synthetic plastics
material, it is also necessary to pass the material through
a drying gelling or curing oven. Here the fabric to be
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coated is, in one method, passed under a bath of the coat-
ing material and a precisely settable gap between a knife
and a roller supporting the coated material controls the
thickness of the coating. Thereafter the material is passed
through the oven to gell or cure the coating material.
In such a machine there are also difficulties in support-
ing the fabric without distortion in its passage through
the oven. Although the fabric can be coated on both sides
the additional w~ight thus placed on the fabric may
result in an unacceptable sagging of the material in the
oven bringing the material close to or actually in contact
with the oven with possibly disastrous consequences. These
problems can to some extent be offset by reducing the un-
supported travel of the coated material through the oven,
but this also reduces the heat which can be imparted to the
material and may result in additional passes through the
machine being required with consequent increase in process
times and expense. These problems may also be offset by
employing archback flotation ovens, but such machines are
complicated and expensive to produce and operate.
According to one aspect of the present invention, there
is provided a fabric production treatment, or finishing
machine comprising a plurality of guides disposed to pro-
vide two endless paths each having a common section passing
over a heatable curved treatment surface, two endless
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belts disposed for movement around respective endless
paths, and means for feeding in a fabric to be treated
on the treatment surface so that the fabric is received
between the belts during its passage over the surface,
the arrangement being such that fabric can be success-
ively heated and cooled whilst sandwiched between the belts.
A preferred embodiment of the invention may include
any one or more of the following advantageous features:-
(a) The curved treatment surface is constituted bythe surface of a heatable treatment roller.
(b) An unheated treatment roller is disposed down-
stream of the heatable roller of (a) and lying
on the common section.
~c) The heatable treatment roller of (a) and the
unheated treatment roller of (b) are arranged
relative to one another to define a nip there-
between lying on the common section.
(d) Two heatable treatment rollers are disposed
adjacent one another to define a nip lying
on the common section.
(e) An unheated treatment roller lies downstream
- of the heatable rollers of ~d) on the common
section.
(f) There are three pairs of treatment rollérs.
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(g) Two of the three pairs of treatment rollers
of (f) are heatable.
(h) The or each heatable curved treatment surface
is oil or steam heated.
(i) The or each heatable curved treatment surface is
electrically heated.
(j) The means for feeding in a fabric comprises a
take-off roller.
(k) The endless belts are coated with a low friction
material.
(1) The belts have a woven glass fibre base with a
silicon rubber coating.
(m) The belts have a woven glass fibre base with
polytetrafluoroethylene coating.
(n) Apparatus is provided for coating the fabric
before entry into the treatment rollers.
(o) A reel-up roller is provided to receive the
fabric after leaving the common section.
(p) One or the treatment roller is directly driven
and any other treatment rollers are directly
driven from that directly driven treatment
roller.
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(q) The reel-up roller of (o) is directly driven
or indirectly driven from the driven treat-
ment roller of (p).
(r) One or both of the belts may be in the form
of a lattice.
(s) Where there are two rollers defining a nip,
the nip is fixed and has a dimension less than
the sum of the thicknesses of the two end-
less belts and the fabric passing therethrough
in operation of the machine.
(t) Where there are two rollers defining a nip one
of the rollers defining the nip is fixed and
the other is movable and can be pressured to
squeese the belts and fabric passing therethrough
during operation of the machine.
(u) Where there are two rollers defining a nip, the
nip is nominally fixed but one of the rollers
defining the nip is movable so that it can
adjust to varying thicknesses of belt and fabric
passing therethrough during operation of the
machineO
(v) The belts are tensioned to squeeze the fabric
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during opera-tion of the machine.
(w) Those parts of the machine supporting
the endless belts are can-tilevered to
facilitate removal and replacement of
the belts.
According to another aspect of the present invention,
there is provided a method of producing, treating or finish-
ing a fabric including the steps of sandwiching a fabric
between two belts of material, passing the sandwich so
formed over a heated curved treatment surface so as to heat
it, cooling the sandwich to cool the fabric, and then
removing the fabric from between the two belts.
The invention also comprises a fabric produced, treated
or finished on the above defined machine or by the above
defined method.
In order that the invention may be more clearly under-
stood, one embodiment thereof will now be described, by way
of example, with reference to the accompanying drawings, in
which:-
Figure 1 shows a diagrammatic side elevational viewof a fabric coating machine, and
Figure 2 shows a side elevational view of a fabric
treatment machine.
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Referring to Figure 1 , the machine comprises six
treatment rollers 1 to 6 arranged in two rows with the
rollers of one row adjacent but staggered relative to the
rollers in the other row, such that a total of five nips
are formed therebetween. Six guide rollers 7 to 12 are
disposed around the array of treatment rollers. A first,
upper, endless belt 13 is guided by the guide rollers 7,
8 and 9 and runs through the five nips formed by the
treatment rollers 1 to 6. A second, lower, endless belt
14 is guided by the guide rollers 9, 10, 11 and 12 and
also runs through -the five nips formed by the treatment
rollers 1 to 6. Both endless belts 13 and 14 comprise a
woven glass fibre base coated with polytetrafluoroethylene
(PTFE) or other similar low friction material. An alterna-
tive belt, for example, comprises a woven glass fibre basecoated with silicone rubber~ The type of belt chosen
is chosen in dependence upon the fabric being produced, trea-
ted or finished and upon the nature of the process itself.
In some processes, for example, it has been found advan-
tageous to employ silicone rubber coated glass fibre woven
belts where the coating is very thin on one side, but
approximately 15 X 10 3 inches thick on the other side.
Again, if desired, the surface of the belt could be dimpled
or otherwise specially formed.
There are two further rollers, respectively referenced
15 and 16. Roller 15 is a lead in roller from which the
fabric 17 to be treated is supplied and roller 16 is a
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reel-up roller on which the treated fabric is taken up.
The guide rollers 7 and 12 are disposed in relation to
the first roller 1 of the treatment roller array, such
that the belts 13 and 14 form an acute "V" shape and the
lead in roller 15 is disposed in relation to the rollers
1, 7 and 12 such that the fabric 17 to be treated enters
the array equidistantly spaced from the belts 13 and 14~
A double sided coating apparatus 18 is disposed for
coating the fabric leaving the roller 15. The coating
material may, for example, be polyvinyl chloride (P~VDCJ )~
Four (referenced 1, 2, 4 and 5) of the six treatment
rollers are heated and the remaining two 3 and 6 are cold.
The heated rollers are preferably electrically heated, but
steam or other means may be used as desired. When steam
or other heating medium is used rotatable joints are re-
quired for conducting steam from outside the treatment
rollers 1, 2, 4 and 5 to the interior of the rollers~ For
example, the heating medium could be electrically heated oil.
The rollers are preferably of stainless steel but may be
made of any other suitable material. The rollers 1 to 6
are drivably connected together and one treatmen-t roller is
itself directly driven, this drive being transmitted to
the other rollers by the drive connection. The five nips
between the treatment rollers 1 to 6 are precisely adjusted
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usually to a dimension lessthan the thickness of the
finished fabric to be treated and the two belts 13 and
14.
In operation of the machine, the fabric is drawn
through the treatment rollers by the rotation of the
treatment rollers -themselves. As it is drawn off the
roller 15, the fabric 17 is coated by the apparatus 18,
and as the coated fabric reaches the first treatment
roller 1 it is clasped between the two PTFE belts 13
and 14. The belts 13 and 14 and fabric 17 move in
synchronism through the treatment roller array and are
heated as they do so thus promoting gelation of the coat-
ing. After gela-tion, the fabric is cooled by being passed,
still between the belts 13 and 14, over the cold rollers
3 and 6. There will be a tendency for the cold rollers
3 and 6 to pick up heat from the fabric and in order to
maintain the rollers at the required low temperature
(i.e. unheated) cooling of these rollers may be necessary.
At the guide roller 9 the belts 13 and 14 again follow
their separate paths and the coated fabric passes to the
reel-up roller 16~ This roller 16 may be driven independ-
ently or from a drive take-off from the treatment rollers.
Because of the nature of the belts 13 and 14 and the fact
that the coating has been cooled there is no damaging
adhesion be-tween the belts and fabric at the roller 9
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or betweel~ adjacent turns of the fabric on the
roller 16.
Figure 2 is a more detailed drawing of a modi-
fied version of the machine shown in Figure 1. As com-
pared with the machine of Figure 1, the machine of
Figure 2 comprises only four treatment rollers 201, 202,
204 and 205 arranged in relation to one another to define
t~ree nips therebetween. Eight quide rollers 208 to 212
and 230 to 232 are disposed around the array of treatment
rollers~ A first, upper, endless bel* 213 is guided by
the guide rollers 231, 230, 208 and 209 and runs through
the three nips formed by the treatment rollersO A second,
lower, endless belt 214 is guided ~ythe guide rollers 209,
232, 210, 211 and 212 and also runs through the three nips.
Both endless belts 213, 214 are of similar construction and
material to the belts 13 and 14 of the machine of Figure 1.
Rollers 204 and 205 can be adjusted by means of respective
adjustment mechanisms 235 and 236 so that the dimensions
of the nips can be adjusted. Guide rollers 208 and 232 are
mounted on adjustment mechanisms 250 and 251 to permit
adjustment of the rollers 208 and 232 to tension respective
belts 213 and 214.
A lead in roller 215 is provided on a support 237 from
which the fabric 217 to be treated is supplied and a reel-up
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roller 216 is provided on a support 238 on which the
treated fabric is taken up The suppor~ 237 and 238 are
themselves connected to a main support 239 to which the
main frame of the machine 240 is also connected. The sup-
port for the various rollers is cantilevered to facili-
tate removal and replacement of the endless belts 213 and
214.
A belt sensing unit 241 is associated with the guide
rollers 230 and 231 and a belt sensing unit 242 is assoc-
iated with the guide rollers 211 and 212. The rollrs 230
and 231 are moun-ted in a bracket 243 which is itself moun-
ted for pivotal movement about a pivot 244. The rollers
230 and 231, bracket 243 and belt sensing unit 241 together
form a tracking assembly for the belt 213~ Guide rollers
211 and 212 are mounted in a bracket 245 which is itself
mounted for pivotal movement about a pivot 246. These
rollers 211 and 212 and bracket 245 form together with the
sensing unit 242 a belt tracking assembly for the belt 214.
The sensing units 241 and 242 may be optical (for example
comprising a photoelectric cell) or mechanical (for example
working on an air jet). The tracking assemblies serve to
keep the belts 213 and 214 in position by continuously
sensing and correcting any tendency of the belts to stray
from their desired paths.
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Treatment rollers 201, 202 and 204 are heated and
roller 205 is unheated. The treatment rollers are
substantially of the same construction and material as
those of the machine of Figure 1. In particular the
heated rollers may be electrically steam or oil heated.
The treatmen-t rollers are also driven in the same way as
those of the machine of Figure 1.
The machine is operated in the same manner as the
machine of Figure 1, the fabric being produced, treated
or finished being successively heated and cooled and,
although a coating head has not been described, one
could clearly be added if desired.
The above described machines and method may be
employed for the gelation of PVC plies where the lead
in is almost ideal or for general PVC gelation use. One
or both sides can be gelled in one pass and heavier
coated fabric weights can be accornmodated than hitherto.
Energy savin~ as compared to conventional processes could
4 be 40/50% ~ the cost of the machine may well only be
one half of that of a conventional drying oven. Less space
~up to 75%) is also required for the machine.
The method and machines described may also be used
for fabric to fabric lamination with adhesive, with the
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energy, cost and space saving mentioned above. They
may also be used for heat setting of fabrics such as
nylon and polyester, or heat setting of natural fabrics,
resin curing after drying in conventional finishing, or
simply to dry a fabric. When simple drying is the object
one or both of the belts may be in the form of a lattice.
With the above described method and machine, the fabric
being treated is positively held whilst being heated and
cooled. Marking off faults associated with drawing off
the fabric from a hot drum whilst the fabric itself is
still hot can therefore be avoided.
It will be appreciated that the above embodiment has
been described by way of example only and that many varia-
tions are possible without departing from the scope of the
invention claimed. For example, in any use of the des-
cribed machine of Figure 1 not involving fabric coating,
the coating apparatus 18 would clearly not be necessary
and could be dispensed with. Where fabrics are to be coat-
ed with a solvent or aqueous coating, the upper endless
belt 13 of the machine of Figure 1 preferably follows the
alternative path shown in the drawing by a dashed line.
For this purpose, the guide roller 7 would be replaced by
a differently disposed guide roller 30. Again, instead
of having coating apparatus 18~ coating apparatus 40
could be provided for coa-ting the upper surface of the
i~;350~8
bottom belt as shown in dashed outline in the drawing.
Although the nips between the rollers of the two
described machines are adjustable, once adjusted, they
are fixed at a gap dimension slightly less than the
thickness of belts plus fabric. Other ways of pressur- -
ing the fabric passing through the machine could however
be employed. One roller of a nip could be fixed and the
other pressured to squeeze the fabric. Both rollers of
the nip could be tied to a nominal minimum nip gap, but
one could be movable to accommodate variations in the
thickness of the fabric and belt. If desired, the fabric
could be squeezed simply by tensioning the endless belts
appropriately.
It should be understood that the word fabric has
been used in the specification in its broadest sense and
includes in addition to textile sheet material of the woven,
non-woven or knitted types other types of sheet material
shuch as synthetic plastics, for example, polyvinyl
chloride (PVC) and polyurethane; leather, felt, rubber
and paper or combinations thereof.
