[0001] The present invention relates to an apparatus and a method for continuously treating
a fabric by means of vibrations which are propagated within a fluid means and are
capable of causing substantially undulatory shaking of the fabric, thereby favouring
the penetration of the fluid means into the fabric or removal thereof from the fabric.
[0002] The patent application WO 98/15679 relates to a method and a device for the continuous
ultrasound washing of textile materials extended on conveyor belts or similar conveying
elements. The ultrasound energy is applied to the material to be washed by means of
flexural vibrating plates which are arranged in direct contact with the material to
be washed, the latter being immersed in a shallow liquid means. The cleaning process
may be completed by means of immediate rinsing and, once the liquid has been removed,
the ultrasound energy may again be applied by means of contact in order to eliminate
a significant portion of liquid retained by the washed material, so as to perform
pre-drying. A device capable of implementing the abovementioned process is also described.
[0003] With this known method and device, the fabric, while it is transported in a longitudinal
direction by a conveyor belt or a roller, is subjected to perpendicular vibrations,
in a transverse plane, by a vibrating plate which has a fixed position.
[0004] This arrangement has various drawbacks. The main drawback is that the fabric is subjected
to opposing tensile stresses, respectively imparted by the belt or the conveyor roller,
tending to cause it to advance, and by the fixed plate, tending to brake its movement
so as to cause it to vibrate perpendicularly in a transverse plane. Basically, the
fabric performs stepwise movements, adhering to the plate and being separated from
it. These opposing tensile stresses tend to cause damage to the fabric, such as distortion,
abrasion and laceration.
[0005] The present invention relates to a method and an apparatus for treating a fabric
by means of vibrations which enable the abovementioned drawbacks to be overcome.
[0006] A first aspect of the invention consists in an apparatus for continuously treating
a fabric by means of vibrations, said apparatus comprising:
a) first means for guiding and feeding said fabric,
b) a vibration source,
c) means capable of vibrating and associated with said fabric,
d) second means for guiding and feeding said fabric, and
e) third means for guiding said fabric, arranged between said first and second guiding
and feeding means, said third guiding means being in direct contact with said fabric
and being movable therewith,
characterized in that
f) said third guiding means are associated with said vibration source and themselves
form said means capable of vibrating, said third guiding means being subjected to
vibrations which are transmitted directly to said fabric.
[0007] According to one embodiment, said apparatus also comprises a bath composed of a fluid
means in which said fabric is immersed, said first guiding and feeding means being
located upstream of said fluid means and directing said fabric inside said fluid means,
said second guiding and feeding means being located downstream of said fluid means
and extracting said fabric from said fluid means, said third means for guiding said
fabric, which are associated with said vibration source and themselves form said means
capable of vibrating, being located inside said fluid means and being subjected to
vibrations which are transmitted directly to said fabric while it is immersed in said
fluid means.
[0008] Preferably, said third guiding means are formed by a guiding cylinder which is capable
of vibrating and comprises a rotor and a stator.
[0009] Advantageously, said rotor has an annular wall which is capable of vibrating and
around which said fabric is wound.
[0010] Preferably, said annular wall is made of ferromagnetic material and said vibration
source comprises an oscillating magnetic-field generator.
[0011] Advantageously, said oscillating magnetic-field generator is supported by said stator,
said stator comprising a cylindrical core made of ferromagnetic material and provided
with peripheral longitudinal grooves inside which windings of electrical conductors
connected to an alternating-current power supply, at a preseleted frequency, are housed.
[0012] Preferably, said annular wall is made of sheet steel of limited thickness.
[0013] According to a variant, said annular wall is made of sheet steel of limited thickness
and is connected to a series of T-shaped sections arranged radially.
[0014] According to another variant, said annular wall is formed by a metal sheet of moderate
thickness, provided with internal longitudinal grooves.
[0015] According to a further variant, said annular wall is formed by a metal sheet of moderate
thickness, provided with external longitudinal grooves.
[0016] According to another embodiment, said apparatus comprises an additional roller having
a wall located practically in contact with said annular wall of said cylinder, such
that said additional roller presses said fabric against said annular wall.
[0017] Advantageously, said rotor is rotatably supported by a fixed shaft to which said
stator is integrally joined.
[0018] Preferably, said annular wall is kept in position with respect to two end disks by
means of screws and is supported by means of O-rings, said disks being supported by
said shaft by means of bearings and O-rings.
[0019] A second aspect of the invention consists in a fabric guiding cylinder comprising
a rotor and a stator, characterized in that said rotor has an annular wall which is
capable of vibrating and around which said fabric is wound.
[0020] Preferably, said annular wall is made of ferromagnetic material and is associated
with an oscillating magnetic-field generator.
[0021] Advantageously, said oscillating magnetic-field generator is supported by said stator,
said stator comprising a cylindrical core made of ferromagnetic material and provided
with peripheral longitudinal grooves inside which windings of electrical conductors
connected to an alternating-current power supply, at a preselected frequency, are
housed.
[0022] Preferably, said annular wall is constructed as described further above.
[0023] A third aspect of the invention consists in a method for continuously treating a
fabric by means of vibrations, comprising the steps of:
i) feeding said fabric by means of first guiding and feeding means,
ii) generating said vibrations,
iii) subjecting said fabric to vibrations,
iv) feeding said fabric by means of second guiding and feeding means, and
v) guiding said fabric by means of third guiding means arranged between said first
and second guiding and feeding means, placing said third guiding means in direct contact
with said fabric and causing them to move therewith,
characterized in that
vi) said operations iii) and v) are both performed by said third guiding means, subjecting
them to vibrations, and said vibrations are transmitted directly to said fabric.
[0024] Advantageously, said operation vi) is performed in a fluid means.
[0025] In some cases, said fluid means consists of a liquid and/or of a liquid solution.
[0026] In further cases, said fluid means consists of a suspension of a solid substance
in a liquid.
[0027] In still further cases, said fluid means consists of a substantially solid substance.
[0028] As a result of the apparatus and the method according to the invention, it is possible
to increase the kinetic effect of penetration of a fluid means into the fabric or
removal of the fluid means from the fabric.
[0029] This is due mainly to the direct contact between fabric and vibrating guiding means
which causes undulatory shaking of the fabric and a parallel pumping action of the
fluid means. The vibrating guiding means subject the fabric to alternating displacements
and, at the same time, during acceleration, presses the fabric against the surrounding
fluid means, increasing the pressure thereof, whereas, during deceleration, they subject
it to a sucking action, generating a vacuum in the fluid means.
[0030] The vibrations to which the fabric is subjected cause, moreover, an alternating pulling
action in the fabric portions lying, respectively, between the first guiding means
and the vibrating guiding means and between the latter and the second guiding means.
These alternating pulling actions cause agitation of the fibres, which further favours
penetration of the fluid means into the fabric or removal thereof from the fabric.
[0031] In the case where the vibrating guiding means consist of a vibrating cylinder and
an additional roller which presses the fabric against the vibrating cylinder is used,
the additional roller prevents the displacement of the fabric and the fluid means
in the zone of contact with the vibrating cylinder. This results in a considerable
increase in the pumping action due to the vibration of the cylinder guiding the fabric.
[0032] Finally, when the vibrating cylinder is provided with an annular wall having external
longitudinal grooves, its deformations, due to the vibrations, cause widening and
narrowing of the grooves. The fluid means is thus expelled and sucked back into the
grooves. This interstitial pumping action ensures that the fabric, when passing in
the vicinity of the grooves, is acted on by an alternating flow of fluid means which
improves the penetration of the fluid means into the fabric.
[0033] Characteristic features and advantages of the invention will now be illustrated with
reference to embodiments shown, by way of a non-limiting example, in the accompanying
figures in which:
Fig. 1 is a partially sectioned schematic front view of an apparatus for continuously
treating a fabric by means of vibrations, provided in accordance with the invention;
Fig. 2 is a partially sectioned side view of the apparatus according to Fig. 1;
Fig. 3 shows a longitudinally sectioned view, on a larger scale, of a cylinder of
the apparatus according to Figs. 1 and 2;
Fig. 4 is a partial view sectioned along the plane indicated by IV-IV in Fig. 3;
Figs. 5, 6 and 7 are cross-sectional views of variants of the cylinder according to
Figs. 1-4;
Figs. 8, 9 and 10 show vibration modes of the cylinder according to Figs. 1-4;
Figs. 11, 12 and 13 show effects obtained with the apparatus according to Figs. 1-6;
Fig. 14 shows an additional effect obtained with the cylinder according to Fig. 7.
[0034] Figs. 1 and 2 show an apparatus for continuously treating a fabric 1 by means of
vibrations. The apparatus comprises two motorized rotating rollers 5 and 6 which guide
and feed the fabric 1. The rotating rollers 5 and 6 are located respectively upstream
and downstream of a treatment tank 4 containing a fluid bath 3, for example consisting
of a liquid and/or a liquid solution such as a chemical compound suitable for cleaning
or shrinking or dyeing the fabric, a cleansing liquid and/or solvent, or a suspension
of water and abrasive compounds or a substantially solid substance formed by abrasive
means such as sand or dust. The rotating roller 5 is located at the inlet of the treatment
tank 4 and causes the fabric. 1 to be immersed in the fluid means 3. The rotating
roller 6 is located at the outlet of the treatment tank 4 and extracts the fabric
1 from the fluid means 3. The tank 4 has, mounted inside it, a cylinder 2 which guides
the fabric 1 and is capable of vibrating. The cylinder 2 comprises a rotor 20 and
a stator 21 (Figs. 3 and 4).
[0035] The rotor 20 is rotatably supported (in a idle manner) by a fixed shaft 22. The rotor
20 has an annular wall 9 which is capable of vibrating and around which the fabric
1 is wound. The annular wall 9 is made of ferromagnetic material and has, associated
with it, a vibration source 19 comprising an oscillating (or pulsating) magnetic-field
generator. The annular wall 9 is kept in position with respect to two end disks 23
by means of screws 24 and is supported by means of O-rings 12. The disks 23 are rotatably
supported by the shaft 22 by means of two roller bearings 13 and two O-rings 14. The
annular wall 9 is made of sheet metal of limited thickness, for example, it is made
of steel with 4% Si and has a thickness of between about 1 and 3 mm, for example about
1.5 mm.
[0036] The shaft 22 is fixed to a wall 25 of the tank 4 by means of a bolt 26 and is mounted
on a hatch 27 by means of an 0-ring 28.
[0037] The stator 21 is integrally joined to the shaft 22 by means of an interference connection,
not shown, and a Seeger ring 35 and supports the oscillating magnetic-field generator
19. The generator 19 comprises a cylindrical core 30 made of ferromagnetic material
and provided with peripheral longitudinal grooves 31 and windings of electrical conductors
10 housed in the grooves 31. The electrical windings 10 are connected to an alternating-current
power supply 7, at a preselected frequency, by means of terminals 11 and a cable 16.
The cable 16 passes through an internal hole 15 of the shaft 22.
[0038] A single-phase, two-phase or three-phase alternating current with a frequency of
between 50 and 2000 Hz, for example 1600 Hz, is used to supply the windings 10.
[0039] When the windings 10 have an alternating current at the preselected frequency flowing
through them, they generate a magnetic field oscillating (or pulsating) radially at
the specific frequency. The magnetic field may be formed with two, four or more poles.
The oscillating magnetic field generates, in turn, radially pulsating magnetostrictive
forces which act on the annular wall 9 of the cylinder 2 and deform it, causing it
to vibrate. The deformations of the wall 9 are essentially radial and correspond to
its natural vibration frequencies, as shown in Figs. 8-10.
[0040] When the apparatus is operating, the fabric 1 is guided by the roller 5 so as to
enter into the treatment tank 4. Inside the tank 4, the fabric 1 is immersed in the
fluid means 3 and is wound around the wall 9 of the vibrating cylinder 2 which is
made to vibrate by the action of the oscillating magnetic field 19. The fabric 1 is
kept in contact with the wall 9 of the vibrating cylinder 2 by the pulling tension
exerted by the rollers 5 and 6. The tension may be set to a predefined constant value
by means of a different speed of rotation of the rollers 5 and 6. The fabric 1 is
guided along its path through the tank 4 by the vibrating wall 9 of the rotor 20 which
is mounted idle on the shaft 22 and is free to rotate about it. Then, the cylinder
2 causes the fabric 1 to vibrate and guides it, moving together with it. This prevents
scoring and damaging of the fabric.
[0041] The annular wall 9 of the cylinder 2 transmits the vibrations directly to the fabric
1 which is in contact with it. The fabric 1 and wall 9 thus vibrate in unison and
thus perform an alternating movement away from and towards the axis of the cylinder
2. In so doing they alternately compress the fluid means 3 and create a vacuum in
the fluid means, producing, in the fluid means, pressure waves which are propagated
radially towards the outside the tank 4. This thus produces a combined action consisting
of an undulating shaking movement of the fabric and radial (parallel) pumping of the
fluid means (Fig. 11) which favours the penetration of the fluid means into the fabric.
[0042] The vibrations of the fabric also cause an alternating pulling action (Fig. 12) in
the fabric portions lying, respectively, between the roller 5 and the vibrating cylinder
2 and between the vibrating cylinder 2 and roller 6. This causes agitation of the
fibres which favours the penetration of the fluid means into the fabric or its removal
from the fabric.
[0043] The tank 4 has, mounted inside it, an additional roller 8 (Figs. 1 and 2) having
a wall 18 located practically in contact with the wall 9 of the cylinder 2. The roller
8 presses the fabric 1 against the vibrating cylinder 2, preventing radial displacement
of the fabric and the fluid means in the zone of contact with the vibrating cylinder
2, in the manner of an anvil. Thus the roller 8 induces a tangential (perpendicular)
pumping action (Fig. 13) and amplifies significantly the pumping action due to vibration
of the cylinder 2 alone.
[0044] The fabric 1, steeped with fluid means, is extracted from the tank 4 by the roller
6 which guides it towards the outlet of the treatment apparatus.
[0045] Fig. 5 shows a guiding cylinder 50 which is capable of vibrating and which is a variant
of the cylinder 2. The cylinder 50 has a rotor 53 comprising an annular wall 51 made
of sheet steel of limited thickness and connected to a series of T-shaped sections
52 arranged radially. When an oscillating magnetic field similar to that of the cylinder
2 is present, the annular wall 51 vibrates in the manner of the annular wall 9.
[0046] Fig. 6 shows a guiding cylinder 16 which is capable of vibrating and which forms
another variant of the cylinder 2. The cylinder 16 has a rotor 63 comprising an annular
wall 61 formed by a metal sheet of moderate thickness, for example about 10 mm, provided
with internal longitudinal grooves 62. When an oscillating magnetic field similar
to that of the cylinder 60 is present, the annular wall 61 of the cylinder 60 is subjected
to essentially torsional vibrations.
[0047] Fig. 7 shows a guiding cylinder 70 which is capable of vibrating and which is a further
variant of the cylinder 2. The cylinder 70 has a rotor 73 comprising an annular wall
71 formed by a metal sheet of moderate thickness, for example about 10 mm, provided
with external longitudinal grooves 72. When an oscillating magnetic field similar
to that of the cylinder 2 is present, the annular wall 71 of the cylinder 70 is subject
to several (radial and torsional) vibration modes.
[0048] When the annular wall 71 vibrates and is deformed, the grooves 72 expand and contract.
This thus results in an interstitial pumping action of the fluid (liquid) means present
inside them (Fig. 14). The fabric which passes in the vicinity of the grooves is acted
on by an alternating flow which improves the penetration of the fluid means into the
fabric.
[0049] The vibrations of the cylinder 2, or 50, 60, 70, may be obtained by means of radially
oscillating or pulsating magnetic forces which deform the annular wall 9, or 51, 61,
71, as described further above, or by means of similar systems, for example, by means
of a variable twisting moment which produces torsional vibrations of the annular wall
or by causing vibration of the rotor by means of displacement of its axis of symmetry.
[0050] A cylinder capable of guiding the fabric and vibrating, such as the cylinder 2, or
one of the cylinders 50, 60, 70, may be used to dry the fabric downstream of the roller
6. In this case, the drying cylinder is located inside a chamber containing air.
1. Apparatus for continuously treating a fabric (1) by means of vibrations, said apparatus
comprising:
a) first means (5) for guiding and feeding said fabric (1),
b) a vibration source (19),
c) means (2; 50; 60; 70) capable of vibrating and associated with said fabric (1),
d) second means (6) for guiding and feeding said fabric (1), and
e) third means (2; 50; 60; 70) for guiding said fabric (1), arranged between said
first and second guiding and feeding means (5, 6), said third guiding means (2; 50;
60; 70) being in direct contact with said fabric (1) and being movable therewith,
characterized in that
f) said third guiding means (2; 50; 60; 70) are associated with said vibration source
(19) and themselves form said means (2; 50; 60; 70) capable of vibrating, said third
guiding means (2; 50; 60; 70) being subjected to vibrations which are transmitted
directly to said fabric (1).
2. Apparatus according to Claim 1, characterized in that it also comprises a bath composed
of a fluid means (3) in which said fabric (1) is immersed, said first guiding and
feeding means (5) being located upstream of said fluid means (3) and directing said
fabric (3) inside said fluid means (3), said second guiding and feeding means (6)
being located downstream of said fluid means (3) and extracting said fabric (1) from
said fluid means (3), said third means (2; 50; 60; 70) for guiding said fabric (1),
which are associated with said vibration source (19) and themselves form said means
(2; 50; 60; 70) capable of vibrating, being located inside said fluid means (3) and
being subjected to vibrations which are transmitted directly to said fabric (1) while
it is immersed in said fluid means (3).
3. Apparatus according to one of Claims 1 and 2, characterized in that said third guiding
means (2; 50; 60; 70) are formed by a guiding cylinder (2; 50; 60; 70) which is capable
of vibrating and comprises a rotor (20; 53; 63; 73) and a stator (21).
4. Apparatus according to Claim 3, characterized in that said rotor (20; 53; 63; 73)
has an annular wall (9; 51; 61; 71) which is capable of vibrating and around which
said fabric (1) is wound.
5. Apparatus according to Claim 4, characterized in that said annular wall (9; 51; 61;
71) is made of ferromagnetic material and said vibration source (19) comprises an
oscillating magnetic-field generator.
6. Apparatus according to Claims 3 and 5, characterized in that said oscillating magnetic-field
generator (19) is supported by said stator (21), said stator (21) comprising a cylindrical
core (30) made of ferromagnetic material and provided with peripheral longitudinal
grooves (31) inside which windings of electrical conductors (10) connected to an alternating-current
power supply (7), at a preselected frequency, are housed.
7. Apparatus according to Claim 5, characterized in that said annular wall (9) is made
of sheet steel of limited thickness.
8. Apparatus according to Claim 5, characterized in that said annular wall (51) is made
of sheet steel of limited thickness and is connected to a series of T-shaped sections
(52) arranged radially.
9. Apparatus according to Claim 5, characterized in that said annular wall (61) is formed
by a metal sheet of moderate thickness, provided with internal longitudinal grooves
(62).
10. Apparatus according to Claim 5, characterized in that said annular wall (71) is formed
by a metal sheet of moderate thickness, provided with external longitudinal grooves
(72).
11. Apparatus according to Claim 3, characterized in that said rotor (20; 53; 63; 73)
is rotatably supported by a fixed shaft (22) to which said stator (21) is integrally
joined.
12. Apparatus according to Claims 4 and 11, characterized in that said annular wall (9)
is kept in position with respect to two end disks (23) by means of screws (24) and
is supported by means of O-rings (12), said disks (23) being supported by said shaft
(22) by means of bearings (13) and O-rings (14).
13. Apparatus according to Claims 3 and 4, characterized in that it comprises an additional
roller (8) having a wall (18) located practically in contact with said annular wall
(9; 51; 61) of said cylinder (2), such that said additional roller (9) presses said
fabric (1) against said annular wall (9; 51; 61).
14. Guiding cylinder (2; 50; 60; 70) for a fabric (1), comprising a rotor (20; 53; 63;
73) and a stator (21), characterized in that said rotor (20; 53; 63; 73) has an annular
wall (9; 51; 61; 71) which is capable of vibrating and around which said fabric (1)
is wound.
15. Guiding cylinder (2; 50; 60; 70) according to Claim 14, characterized in that said
annular wall (9; 51; 61; 71) is made of ferromagnetic material and is associated with
an oscillating magnetic-field generator (19).
16. Guiding cylinder (2; 50; 60; 70) according to Claims 14 and 15, characterized in that
said oscillating magnetic-field generator (19) is supported by said stator (21), said
stator (21) comprising a cylindrical core (30) made of ferromagnetic material and
provided with peripheral longitudinal grooves (31) inside which windings of electrical
conductors (10) connected to an alternating-current power supply, at a preselected
frequency, are housed.
17. Guiding cylinder (2; 50; 60; 70) according to Claim 15, characterized in that said
annular wall (9) is made of sheet steel of limited thickness.
18. Guiding cylinder (2; 50; 60; 70) according to Claim 15, characterized in that said
annular wall (51) is made of sheet steel of limited thickness and is connected to
a series of T-shaped profiles (52) arranged radially.
19. Guiding cylinder (2; 50; 60; 70) according to Claim 15, characterized in that said
annular wall (61) is formed by a metal sheet of moderate thickness, provided with
internal longitudinal grooves (62).
20. Guiding cylinder (2; 50; 60; 70) according to Claim 15, characterized in that said
annular wall (71) is formed by a metal sheet of moderate thickness provided with external
longitudinal grooves (72).
21. Guiding cylinder (2; 50; 60; 70) according to Claim 14, characterized in that said
rotor (20; 53; 63; 73) is rotatably supported by a fixed shaft (22) to which said
stator (21) is integrally joined.
22. Guiding cylinder (2; 50; 60; 70) according to Claims 14 and 21, characterized in that
said annular wall (9) is kept in position with respect to two end disks (23) by means
of screws (24) and is supported by means of O-rings (12), said disks (23) being supported
by said shaft (22) by means of bearings (13) and O-rings (14).
23. Method for continuously treating a fabric by means of vibrations, comprising the steps
of:
i) feeding said fabric by means of first guiding and feeding means,
ii) generating said vibrations,
iii) subjecting said fabric to vibrations,
iv) feeding said fabric by means of second guiding and feeding means, and
v) guiding said fabric by means of third guiding means arranged between said first
and second guiding and feeding means, placing said third guiding means in direct contact
with said fabric and causing them to move therewith,
characterized in that
vi) said operations iii) and v) are both performed by said third guiding means, subjecting
them to vibrations, and said vibrations are transmitted directly to said fabric.
24. Method according to Claim 23, characterized in that said operation vi) is performed
in a fluid means.
25. Method according to Claim 24, characterized in that said fluid means consists of a
liquid and/or of a liquid solution.
26. Method according to Claim 24, characterized in that said fluid means consists of a
suspension of a solid substance in a liquid.
27. Method according to Claim 24, characterized in that said fluid means consists of a
substantially solid substance.