WO2017081628A1

WO2017081628A1 - Drying machine for fabric and method of drying fabric

Info

Publication number: WO2017081628A1
Application number: PCT/IB2016/056750
Authority: WO
Inventors: Alberto Ciabattini
Original assignee: Coramtex S.R.L.
Priority date: 2015-11-11
Filing date: 2016-11-09
Publication date: 2017-05-18
Also published as: EP3374715A1; CN108291771B; ITUB20155480A1; CN108291771A; BR112018008768A2

Abstract

Drying machine for continuous fabric, comprising A) an initial accumulation station in which the fabric is adapted to enter the machine from the outside, continuously and in open width, with a first speed, and a final accumulation station from which the fabric is adapted to exit toward the outside of the machine, continuously and in open width, with the same said first speed; B) a drying tunnel between said accumulation stations through which the fabric in open width is adapted to pass; C) a device for alternated movement of the fabric between said two accumulation stations, inside said tunnel, with a second movement speed greater with respect to said first speed so as to accumulate fabric alternately on said two accumulation stations, wherein said alternated movement device comprises a bell and a rotating roller arranged inside said bell, said roller being adapted to reverse its direction of rotation, said roller having an inner cavity and a cylindrical surface provided with a plurality of passages toward said inner cavity, the cylindrical surface of said roller and the inner surface of said bell defining between them at least part of said drying tunnel, said fabric being arranged in open width on said cylindrical surface of said roller, said fabric being arranged freely on said roller, in said tunnel and in said accumulation stations; D) a hot air system comprising an air heating station, operatively connected on the delivery side with said drying tunnel, said system also comprising a suction duct for drawing air from inside said roller toward an area outside said tunnel, so that the hot air passes through said tunnel, enters said roller through said passages striking the fabric arranged on said roller, at least partially drying it, and exits from said roller outside said tunnel.

Description

"DRYING MACHINE FOR FABRIC AND METHOD OF DRYING FABRIC"

DESCRIPTION

TECHNICAL FIELD

The present invention relates to the field of industrial systems for producing and treating fabric. More in particular, the invention relates to a drying machine for fabric and to a method of drying fabric. More specifically, the machine refers to a fabric that continuously and constantly enters the machine and that continuously and constantly exits the machine, so that the machine can be used in a continuous production/treatment line, in which the fabric passes continuously between the stations.

The fabric is intended as arranged in open width inside the machine, and can either be of open type, i.e. extending transverse to the fabric feed direction with a single layer (two lateral ends free), or of tubular type, i.e. with transverse section closed in a loop (with no ends, i.e. two lateral ends joined together). Moreover, the fabric is intended as being "arranged freely" in the machine, i.e. it is neither guided laterally nor constrained laterally by means of clamps, pins or the like on a conveyor chain through the drying path.

The present invention, besides concerning the drying of fabrics, also concerns their finishing and allows excellent shrinkage and swelling of the fabric treated to be obtained.

Fabric is meant as a textile product either of knitted type or of woven type.

State of the art

At the state of the art, various methods/ machines for the continuous drying of fabric, arranged freely, are currently known.

A first known machine is the free layer or "loop dryer". This machine consist of an oven of large dimensions (above all in length), having a chamber in which the fabric advances and moves hanging in the upper part on controlled cylinders, suspended in the lower advancing part in free layers or loops. Drying takes place slowly and gradually inside the chamber saturated with hot air. This machine has the drawback of having a very low productivity in terms of drying, large overall dimensions and high energy consumption.

There is also known a "drum dryer" heated with thermal fluid. This machine is provided with a certain number of cylinders heated with fluid on which the fabric runs continuously, winding around a part of them to be heated and dried. This machine has the drawback of giving the fabric a flat and stiff appearance.

There is also known a conveyor relax dryer, in which the fabric is fed through a series of hot air blowers, resting on one or more moving belts, which convey it to the outlet. This type of machine is generally very costly, if compared to the productivity it can achieve.

Object and summary of the invention

The object of the present invention is to solve the aforesaid problems in drying machines of known type.

In particular, an important object of the present invention to produce a drying machine that has a high drying capacity with more compact dimensions with respect to prior art machines with comparable drying power.

Another important object of the present invention is to produce a drying machine that has low energy consumption to heat the air.

Yet another important object of the present invention is to produce a drying machine that allows drying while limiting or eliminating mechanical shocks on the fabric, thereby allowing optimal shrinkage and bulking of the fabric during drying.

A further important object of the present invention is to provide a method for drying fabric that provides a high drying capacity, with low energy consumption, and an optimal shrinkage and bulking treatment of the fabric to be obtained.

These and other objects, which will be more apparent below, are achieved with a drying machine for continuous fabric, which comprises:

- an initial accumulation station in which the fabric is adapted to enter the machine from the outside, continuously and in open width, with a first speed, and a final accumulation station from which the fabric is adapted to exit toward the outside of the machine, continuously and in open width, with the same said first speed;

- a drying tunnel between the two accumulation stations through which the fabric in open width is adapted to pass;

- a device for alternated movement of the fabric between the two accumulation stations, inside said tunnel, with a second movement speed greater with respect to the first speed so as to accumulate fabric alternately on these two accumula- tion stations; the alternated movement device comprises a bell and a rotating roller arranged inside this bell; the roller is adapted to reverse its direction of rotation and has an inner cavity and a cylindrical surface provided with a plurality of passages toward the inner cavity; the cylindrical surface of the roller and the inner surface of the bell define between them at least part of, or at least partly delimit, said drying tunnel; the fabric is arranged in open width on the perforated cylindrical surface of said roller, and is arranged freely on the roller, in the tunnel and in the accumulation stations;

- a hot air system comprising an air heating station, operatively connected on the delivery side with the drying tunnel; the hot air system also comprising a suction duct for drawing air from inside the roller toward an area outside the tunnel, so that the hot air passes through the tunnel, enters the roller through the passages (striking the fabric arranged on the surface of the roller, at least partially drying it), and exits from the roller outside said tunnel.

In practice, the fabric enters and exits the machine at a first speed, while, inside the machine, it is moved to and fro, at a second speed greater than the first, by the movement of the roller on which the fabric adheres by vacuum pressure, or through the effect of the suction of air from inside the roller; as the air is hot, during this alternate movement the fabric is dried.

This machine enables a very high drying capacity to be obtained with a structure of limited size.

It also allows the tension of the fabric to be reduced or eliminated and prevents mechanical shocks, in practice the fabric is not subjected to any violence during drying and all this allows an optimal shrinkage and bulking treatment of the fabric to be obtained. Therefore, the machine, besides being a drying machine, can be seen as a fabric treatment machine adapted to increase the shrinkage and bulking of the fabric.

Moreover, this machine has low energy consumption due to the flow system of hot drying air.

This machine can be used alone, or in line with other machines, for example at the outlet of a fabric washing station, or as pre-drying machine at the inlet of a tumbler for specific final treatment of the fabric.

According to preferred embodiments, the roller is motorized and is adapted to draw the fabric, due to the suction that keeps it adhering to the roller, in both directions of rotation.

According to preferred embodiments, the hot air system comprises an air distributor, operatively connected with said air heating station, having at least one diverter adapted to convey the hot air coming from the heating station in one direction of the tunnel or in the opposite direction; preferably there is provided a synchronizing device adapted to synchronize the movement of said at least one diverter and of said rotor so that the at least one diverter is adapted to divert the flow of hot air in the tunnel in the same direction of rotation as the rotor. In this way, the flow of air in the tunnel accom- panies the movement of the fabric, facilitating adhesion of the fabric and drying thereof.

Preferably, the distributor is arranged under the roller; the bell has lower walls that extend below the roller, so that the tunnel has two inlet sections defined between said lower walls and said distributor, and a central section between the cylindrical surface of the roller and the inner surface of said bell.

According to preferred embodiments, the roller rotates on a lower retaining cradle, so that, during rotation, the passages of the part of the surface of the roller that is covered by the cradle are obstructed, and air is not drawn through them.

According to preferred embodiments, the hot air system comprises a duct for discharge into the environment of at least part of the air coming from said suction duct.

According to preferred embodiments, the hot air system comprises a duct for reintroducing at least part of the air coming from said suction duct into said heating station.

Preferably, the suction duct for drawing air from inside said roller toward an area outside said tunnel is divided into the duct for discharge into the environment and into the duct for reintroducing the air into the heating station.

With these configurations an optimal energy saving in the production of the hot air is achieved.

Preferably, the air heating station comprises a compartment and a mouth for conveying air external to the hot air system onto the compartment; preferably said mouth is provided with a filter to prevent debris of the fabric being processed from entering (lint and derivatives of the fabric being processed).

Preferably, the air heating station comprises a burner adapted to directly heat the air present in the compartment, and/or an air/gas heat exchanger adapted to be struck by the air coming from said conveying mouth.

Preferably, the air heating station is arranged under said roller.

Preferably, the accumulation stations are arranged over the heating station and under the tunnel.

According to preferred embodiments, the hot air system comprises a hot air movement device from the heating station to the tunnel, preferably arranged in a section of pipe immediately downstream of the heating station; preferably the hot air movement device is a high capacity low pressure fan.

According to preferred embodiments, the hot air system comprises an air extraction device from the inner cavity of said roller, preferably arranged immediately downstream of said cavity; preferably the air extraction device comprises a suction turbine.

Machine according to one or more of the preceding claims, wherein the initial accumulation station and the final accumulation station comprise respective accumulation tanks with which there are associated respective devices for assessing the quantity/presence of the fabric in these tanks, there being provided electronic control means of the machine that reverse the direction of rotation of the roller when the assessment device of the accumulation tank from which the fabric is picked up detects that a predetermined minimum value of quantity/presence of fabric has been reached.

For example, the assessment device comprises a weight measurer of the respective tank, so that when the weight detected is, for example, equal to that of the tank alone or of the tank plus a given safety mass, the device sends a signal to the electronic control means of the machine that in turn control reversal of the movement of the roller and therefore of the fabric.

The assessment device could comprise technology different from that of weigh assessment, such as an optical system that evaluates the presence of fabric in the tank, for example that evaluates the number of layers or loops of fabric accumulated in the tank, so that when there is no more fabric or the number of layers or loops is below a predetermined value, reversal of the roller is activated.

The tunnel has two opposite inlets; preferably, in proximity of said two inlets, there is provided a respective device for stretching and spreading the fabric entering the tunnel; for example this device comprises a curved cylinder integrated in one piece. According to preferred embodiments, the machine comprises a first drawing cylinder arranged at the inlet of the machine, on which there is arranged, in open width, the fabric coming from another processing/treatment/production area of the fabric, and a second drawing cylinder arranged at the outlet to the machine, on which there is ar- ranged, in open width, the fabric coming from said accumulation station and being directed toward another processing/treatment/production area of the fabric.

According to preferred embodiments, the machine comprises a box-like containment casing, inside which there are arranged at least the following components: the accumulation stations of the fabric, the device for alternated movement of the fabric and the heating station.

According to preferred embodiments, the second movement speed of the fabric in the tunnel is at least double the first speed for inserting/removing the fabric into/from the accumulation stations (the first speed is the speed with which the fabric enters the first accumulation station for the first time and the speed with which it exits the second accumulation station for the last time, i.e. the speed with which the fabric enters and exits the machine) and preferably is at least five times the first speed, and more preferably at least ten times the first speed, and more preferably at least fifteen times said first speed; more preferably said second speed is from five times to thirty times the first speed, and more preferably is from ten times to twenty-five times the first speed, and even more preferably is from fifteen times to twenty times the first speed.

According to another aspect, the invention relates to a method of drying a continuous fabric in open width, which provides for

- inserting, with a first speed, continuously, the fabric arranged in open width, into a initial accumulation station,

- alternately moving, with a second speed greater than said first speed, the accumulated fabric, arranging it in open width on a rotating roller, said roller being internally hollow and perforated on the surface, from said initial accumulation station to a final accumulation station and vice versa; during said alternate movement

striking the fabric from the outside of said roller with a flow of hot air and - drawing said hot air from inside said roller so that the air from the outside the roller passes through the thickness of the fabric arranged on said roller, drying it at least partially and maintaining the fabric adhering to said roller, - continuously extracting said fabric in open width from said final accumulation station, with said first speed,

said fabric is arranged freely on said roller and in said accumulation stations.

Preferably, the second speed is at least double the first speed, and preferably is at least five times said first speed, and more preferably at least ten times said first speed, and more preferably at least fifteen times said first speed; more preferably said second speed is comprised between five times and thirty times said first speed, and more preferably is comprised between ten times and twenty-five times said first speed, and even more preferably is comprised between fifteen times and twenty times said first speed.

Preferably, the roller is adapted to pull the fabric through vacuum pressure created by suction of air from the outside to the inside of the roller, through the thickness of the fabric.

Preferably, the flow of hot air that strikes the fabric outside said roller is substantially concordant with, or accompanies, the direction of movement of the fabric adher- ing to said roller, the flow of hot air reversing its direction when the direction of movement of the fabric adhering to the roller is reversed.

Preferably, the hot air is heated in a heating station and sent to said fabric; at least part of the hot air drawn from inside said roller is returned to said heating station or is discharged into the outside environment.

Preferably, reversal of the movement of the fabric from one accumulation station to the other takes place when the weight/presence of fabric in the accumulation station from which the fabric is picked up has dropped below a threshold value.

Preferably, the fabric that moves from an accumulation station toward the surface of said roller is spread stretched before reaching the roller.

Brief description of the drawings

Further characteristics and advantages of the invention will become more apparent from the following description of a preferred but non-exclusive embodiment thereof, illustrated by way of non-limiting example in the accompanying drawings, wherein figures 1 represents a schematic lateral sectional view of a machine according to the inven- tion.

Detailed description of an embodiment of the invention

With reference to the previously cited figures, a machine according to the inven- tion is indicated as a whole with the number 10.

This machine can be arranged, for example, in line in a continuous fabric treatment system, i.e. the fabric moves continuously between the machines of the system that perform the treatment, therefore, in the example specified, the fabric T continuously enters the machine with a first speed V I and continuously exits with the same first speed V I .

Fabric is intended as a textile product both of knitted and of woven type.

The fabric is intended as arranged in width both when entering and exiting the machine 10, and when inside the machine, and can either be of open type, i.e. extending transverse to the fabric feed direction with a single layer (two lateral ends free), or of tubular type, i.e. with cross section closed in a loop (with no ends, i.e. two lateral ends joined together). Moreover, the fabric is intended as being "arranged freely" through the machine, i.e., it is not guided laterally or constrained laterally by means of clamps, pins or the like on a conveyor chain through the drying path.

The machine 10 comprises a box-like containment casing 1 1 , inside which the various components, described below, are arranged.

The machine comprises electronic means to control operation, such as an electronic control unit indicated schematically with C.

This box-like casing comprises an inlet 1 1 A and an outlet 1 I B for the fabric from the machine.

At the inlet 1 1 A there is provided a first drawing cylinder 12 on which the fabric T is arranged in open width, for example coming from another pro- cessing/treatment/production area of the fabric, adapted to introduce the fabric into the machine with the first speed V I . A second drawing cylinder 13 is provided upstream of the outlet of the machine 1 1 B, which helps extraction of the fabric from the machine with the first speed V I and sends it toward another processing/treatment/production area of the fabric.

Inside the box-like containment casing 1 1 there is provided an initial accumulation station 14 in which the fabric T is adapted to enter from outside the machine, com- ing from the first drawing cylinder 12, and a final accumulation station 15 from which the fabric is adapted to exit toward the outside of the machine, drawn by the second drawing cylinder 13. Each accumulation station 14 and 15 comprises a respective fabric accumulation tank 14A and 15 A, respectively positioned at a lower level to the first drawing cylinder 12 and to the second drawing cylinder 13, where the fabric accumulates in layers or loops.

Between the two accumulation stations 14 and 15 there is arranged a drying tun- nel 16.

There is provided a device 17 for alternated movement of the fabric between the two accumulation stations 14 and 15, inside said tunnel, with a second movement speed of the fabric V2 greater with respect to the first speed V I , so as to alternately accumulate fabric in the accumulation stations 14 and 15.

In practice, the fabric T enters and exits the machine at a first speed V I , while, inside the machine, it is moved to and fro, between the accumulation stations of the fabric 14 and 15, inside the drying tunnel 16, at a second speed greater than the first in this alternate movement, so that the fabric dries without traveling for a considerable distance along a one-way path, to the advantage of the overall dimensions of the machine, which is therefore particularly compact. Due to the adjustability of the machine, it is possible to select the number of forward/reverse passages of the fabric in the drying tunnel, thereby allowing precise control of the degree of drying.

The device for alternated movement 17 comprises a bell 18 and a rotating roller 19 arranged inside this bell 18. The axis of rotation of the roller is parallel to that of the drawing cylinders 12 and 13, i.e., perpendicular to the overall direction of feed of the fabric in the machine (machine direction); the cylindrical surface 19A of the roller 19 and the inner surface 18 A of the bell 18 define between them, or delimit, part of the drying tunnel 16.

The roller 19 has an inner cavity 20 and a plurality of passages 21 provided on the cylindrical surface 19 that lead into the inner cavity 20.

The machine also comprises a hot air system 22 that in turn comprises an air heating station 23 operatively connected on the delivery side with the drying tunnel 16.

The hot air system also comprises a suction duct 24 for drawing air from the inner cavity 20 of the roller 19 (through two sections exiting from the two ends of the roller and then joining again in a common section) toward an area outside the tunnel, so that the hot air (indicated by the letter f) passes through the tunnel, enters the roller 19 through the passages 21 (striking the fabric T arranged on the cylindrical surface 19A of the roller, at least partially drying it), and exits from the roller outside the tunnel. More in particular, the suction duct 24 is divided into a duct 25 for discharge into the environment of part of the air (indicated with f2) coming from the suction duct 24, and into a duct 26 for reintroducing the air (indicated with f3) into the heating station 23.

The air heating station 23 comprises a compartment 23A and a mouth 23B for conveying air external to the hot air system onto the compartment, which in this example draws from inside the box-like containment casing 1 1. In this example, the mouth 23B is provided with a filter to prevent debris from the fabric being processed from entering (lint and derivatives of the fabric being processed). Not shown in the figures, the compartment 23 can be provided with a mouth for conveying new air only, or also, from outside the box-like casing 1 1.

The air heating station 23 comprises a burner 23C adapted to directly heat the air present in the compartment 23A. Alternatively, other means can be present to heat the air, such as an air/gas heat exchanger adapted to be struck by the air coming from the conveying mouth (the hot gas coming from a further heating circuit).

To move the hot air from the heating station 23 to the tunnel 16, there is present a first hot air movement device 27. preferably arranged in a section of pipe immediately downstream of the heating station 23, such as a high capacity low pressure fan.

To move the air from the inner cavity 20 of the roller 19 toward the outside of the tunnel 16, there is provided a device 28 for extracting air from the inner cavity of the roller, such as a suction turbine arranged upstream of the fork in the duct 25 for discharge into the environment and of the duct 26 for reintroducing the air.

The rotating roller 19 is motorized and is adapted to draw with it the fabric arranged on the cylindrical surface 19A, as a result of the suction of air from the inner cavity 20 of the roller 19. The vacuum pressure that forms in the cavity 20, as a result of the passages 21 , maintains the fabric adhering to the cylindrical surface 19 A.

The movement speed V2 of the fabric in the tunnel 16 is given by the rotation speed of the roller. As said, this speed V2 is greater than the speed V I at which the fabric enters and exits the machine 10.

This second speed V2 is adjustable, and in this it is preferably usable at least fifteen times greater than the first speed V I and more preferably from fifteen times to twenty times the first speed, for example equal to around 20 times the speed V 1.The ro- tating roller 19 is controlled to reverse its direction of rotation according to the amount of fabric in the accumulation stations 14 and 15.

There are associated with the first and with the second fabric accumulation tank 14A and 15A respective devices 29 for assessing the amount/presence of the fabric in the tanks associated with the electronic control unit C, in order to perform reversal of the direction of rotation of the rotor 19.

For example, each assessment device 29 comprises a device for measuring the weight of the respective tank, such as a load cell 30, so that when the weight detected is, for example, equal to that of the tank 14A- 15A alone (or of the tank plus a given safety weight), the assessment device 29 sends a signal to the electronic control means C that in turn control reversal of the movement of the roller 19 and therefore of the fabric T.

The assessment device could comprise different technology to that for assessing the weight, such as an optical system that assesses the presence of the fabric in the tank, for example that assesses the number of layers or loops of fabric accumulated in the tank, so that when there is no more fabric or the number of layers or loops is below a predetermined value, reversal of the roller is controlled.

It is understood that other technologies for assessing weight or presence can be used.

The roller 19 rotates on a lower retaining cradle 19B. In this way, during rotation, the passages 21 present on the surface of the roller 19 that are covered by the cradle 19B, are blocked, and air cannot be drawn through them. Therefore, in the area of the passages 21 blocked by the cradle 21 , the fabric cannot adhere to the cylindrical surface, and detaches therefrom, advancing toward the accumulation tank 14A or 15A below.

The hot air system comprises, under the lower retaining cradle 19B of the roller 19, an air distributor 3 1 , operatively connected with the air heating station 23 (i.e. downstream of the pipe 27A for connection to the compartment 23, in which the fan 27 is present), having a pair of diverters 32 adapted to convey the hot air coming from the heating station 23 in the direction of the tunnel 16 or in the opposite direction.

The bell 18 of the device for alternated movement 17 has lower walls 18B that extend below the roller 19, so that the tunnel has two inlet sections 16A defined between the lower walls 18B and the air distributor 31 , and a central section 16B comprised between the cylindrical surface of the roller 19A and the inner surface of the bell 18A.

There is provided a synchronizing device 33, for example integrated in the electronic control unit C, adapted to synchronize the movement of the two diverters 32 and of the rotor 19 so that the diverters are adapted to divert the flow of hot air in the tunnel 16 in the same direction of rotation as the rotor. In this way the flow of air in the tunnel accompanies the movement of the fabric, facilitating adhesion and drying of the fabric. In practice, the two diverters 32 are arranged respectively at two inlet sections 16A of the tunnel. When one diverter is in the closed position (i.e. preventing the passage of hot air between the distributor and the tunnel), the other diverter is open. Therefore, the air flows from the air distributor 31 alternately to one inlet section 16A at a time. With reference to Fig. 1 , the left diverter is closed, while the right is open, so that the air enters the right inlet section 16A, flows through this section and through the subsequent central section 16B of the tunnel and then enters the inner cavity of the roller 19 tlirough the passages 21. In this situation, the roller rotates counter-clockwise R (from right to left with reference to the figure), i.e. rotation is substantially concordant with the flow of air in the tunnel.

In proximity of the two opposite inlets 16A' of the tunnel 16, there are provided respective devices 34 for stretching and spreading the fabric T entering the tunnel. For example, these devices are non-rotating fixed cylinders, with a curved axis, also known as "curved cylinders integrated in one piece". In practice, the fabric rubs on the cylindrical curved surface of the cylinder, and from the top of this the fabric tends to be spread out, avoiding creases from its center to the edges.

Operation of the machine is as follows.

The fabric T is inserted into the box-like containment casing 1 1 , or also drying chamber, by means of the first drawing cylinder 12 at the first speed V I , predetermined and constant, corresponding to the process speed, which allows the fabric to exit completely dry or with the desired residual humidity. The fabric is deposited in the first accumulation tank 14 A, from which it is picked up tlirough the rotating roller 19 at a speed V2 much higher with respect to the first process speed V I (for example around twenty times higher).

The roller 19 on which the cylinder is partially wound is perforated on the surface and is in vacuum pressure by means of the suction turbine 28, which creates a flow of hot air from inside the tunnel 16, through the fabric, inside the roller 19, and exiting (on each side) through the duct 24 directed toward the turbine 28. Part of this air is recirculated through the duct 26 to the heating station 23, and part is expelled to the outside through the duct 24.

Besides performing an optimal drying action due to the air that passes through the fabric (in addition to drying due to the flow of air along the tunnel that laps the fabric), the roller 19 allows a strong grip on the transported fabric, thus avoiding abnormal movements and tension thereof, which are damaging for shrinkage and bulking of the fabric.

The roller 19 "deposits" the fabric picked up from the first tank 14A in the second accumulation tank 15 A, at the speed V2, and is reversed in the direction of rotation when the load cell 30 associated with the first tank 14A indicates the end of the supply of accumulated fabric. In this way, the roller ensures "return" of the fabric, picked up from the second tank 15A and deposited in the first tank 14A, until the load cell 30 as- sociated with the second tank 15A indicates the end of the supply of accumulated fabric, and the cycle is repeated.

The fabric, passing from one accumulation tank to the other, passes through the drying tunnel 16 heated with the hot air coming from the heating station 23. In practice, the drying tunnel 16 "wraps around" or "surrounds" the roller 19 and ends with the two accumulation tanks.

In the tunnel, the fabric is struck by a flow of hot air that is alternated in the tunnel by means of the diverters 32 of the distributor 3 1 , so that this flow is concordant with the movement of the fabric.

The roller 19 allows suction of hot air through the fabric only in the sector of the roller covered by the fabric drawn resting against it and enclosed in the drying tunnel, for the puipose of preventing waste of hot air, and therefore of energy.

The drying air, heated by means of the burner 23C (or by means of a heat exchanger with thermal fluid) in the heating compartment 23A, is introduced into the drying tunnel 16 by the high capacity low pressure fan 27, which picks up the hot air from the compartment 23 A through a suitable delivery pipe 27A to the distributor 31 . The air drawn from the tunnel 16 through the fabric on the perforated roller 19 is then partly expelled through the exhaust pipe 25 and partly recirculated through the duct 26 in the heating station 23.

New external air and recirculated internal air are introduced into the heating compailment 23A through removable filters that intercept any lint that can be produced during drying.

From the second accumulation tank 15 A the fabric is extracted from the machine

10 by means of the second drawing cylinder 13, at the set drying and treatment speed.

With regard to the method of drying of a continuous fabric in open width according to the invention, for example implemented by the machine 10 described above, this provides for

- inserting, with a first speed V I , continuously, the fabric T arranged in open width, into the initial accumulation station 14,

- alternately moving, with a second speed V2 greater than said first speed V 1 , the accumulated fabric, arranging it in open width on the rotating roller 19, with the roller internally hollow and perforated on the surface, from the initial accumulation station 14 to the final accumulation station 15 and vice versa.

During this alternated movement, the method provides for

striking the fabric T from the outside of the roller 19 with a flow of hot air f, and

drawing the hot air f from inside the roller 19 so that the air from the outside of the roller passes through the thickness of the fabric T arranged on the roller, drying it at least partially and maintaining the fabric adhering to this roller,

- continuously extracting the fabric in open width from the final accumulation station

15, with the first speed V 1.

The fabric is arranged freely on said roller and in said accumulation stations.

Preferably, the second speed V2 is at least fifteen times the first speed V I ; more preferably V2 is comprised between fifteen times and twenty times the first speed V I .

The roller 19 is adapted to pull the fabric through vacuum pressure created by suction of air from the outside to the inside of the roller, through the thickness of the fabric.

The flow of hot air f that strikes the fabric outside the roller 19 is substantially concordant with, or accompanies, the direction of movement of the fabric adhering to the roller; the flow of hot air reverses its direction when the direction of movement of the fabric adhering to the roller is reversed.

The hot air is heated in the heating station 23 and sent to the fabric; at least part f2-f3 of the hot air drawn from inside the roller is returned to the heating station 23 or is discharged into the outside environment.

Reversal of the movement of the fabric from one accumulation station 14- 15 to the other takes place when the weight/presence of fabric in the accumulation station from which the fabric is picked up has dropped below a threshold value.

The fabric that moves from an accumulation station toward the surface of the roller 19 is spread out before reaching the roller.

The machine and the method now described allow drying of the fabric arranged freely, in open width, continuously, with very high production capacity in relation to the size of the machine, due to the fact that the fabric is struck by hot air numerous times during its travel through the machine.

Moreover, drying of the fabric takes place without any or with minimum tension or mechanical action on the fabric, which does not undergo any abrasion or defect during treatment, which leads to increased shrinkage, softness and bulking, making the machine and method described optimal for knitwear, terry fabrics, wool, acrylic and cotton blend fabrics.

Moreover, the machine and the method described allow high drying efficiency to be obtained with low energy consumption.

It is understood that the drawing only shows possible non-limiting embodiments of the invention, which can vary in forms and arrangements without however departing from the scope of the concept on which the invention is based. Any reference numerals in the appended claims are provided purely to facilitate the reading thereof, in the light of the above description and accompanying drawings, and do not in any way limit the scope of protection.

Claims

1 ) Drying machine for continuous fabric, comprising

- an initial accumulation station in which the fabric is adapted to enter the machine from the outside, continuously and in open width, with a first speed, and a final ac- cumulation station from which the fabric is adapted to exit toward the outside of the machine, continuously and in open width, with the same said first speed,

- a drying tunnel between said accumulation stations through which the fabric in open width is adapted to pass,

- a device for alternated movement of the fabric between said two accumulation sta- tions, inside said tunnel, with a second movement speed greater with respect to said first speed so as to accumulate fabric alternately on said two accumulation stations, wherein said alternated movement device comprises a bell and a rotating roller arranged inside said bell, said roller being adapted to reverse its direction of rotation, said roller having an inner cavity and a cylindrical surface provided with a plurality of passages toward said inner cavity, the cylindrical surface of said roller and the inner surface of said bell defining between them at least part of said drying tunnel, said fabric being arranged in open width on said cylindrical surface of said roller, said fabric being arranged freely on said roller, in said tunnel and in said accumulation stations,

- a hot air system comprising an air heating station, operatively connected on the delivery side with said drying tunnel, said system also comprising a suction duct for drawing air from inside said roller toward an area outside said tunnel, so that the hot air passes through said tunnel, enters said roller through said passages striking the fabric arranged on said roller, at least partially drying it, and exits from said roller outside said tunnel.

2) Machine according to claim 1 , wherein said hot air system comprises an air distributor, operatively connected with said air heating station, having at least one diverter adapted to convey the hot air coming from said heating station in one direction of said tunnel or in the opposite direction; preferably there being provided a synchroniz- ing device adapted to synchronize the movement of said at least one diverter and of said rotor so that said at least one diverter is adapted to divert the flow of hot air in said tunnel in the same direction of rotation as said rotor. 3) Machine according to claim 1 or 2, wherein said roller is motorized and is adapted to pull said fabric.

4) Machine according to one or more of the preceding claims, wherein said suction duct for drawing air from inside said roller toward an area outside said tunnel is divided into a) a duct for discharge into the environment of at least part of the air coming from said suction duct and b) a duct for reintroducing at least part of the air coming from said suction duct, into said heating station.

5) Machine according to one or more of the preceding claims, wherein said air heating station is arranged below said roller.

6) Machine according to one or more of the preceding claims, wherein said initial accumulation station and said final accumulation station comprise respective accumulation tanks with which there are associated respective devices for assessing the quantity/presence of the fabric in these tanks, there being provided electronic control means of the machine that reverse the direction of rotation of said roller when the as- sessment device of the accumulation tank from which the fabric is picked up detects that a predetermined minimum value of quantity/presence of fabric has been reached, preferably at least one said assessment device comprises a device for measuring the weight of the respective tank, and/or a device for counting the layers of accumulated fabric.

7) Machine according to one or more of the preceding claims, wherein said tunnel has two opposite inlets, in proximity of said two inlets there being provided a respective device for stretching and spreading the fabric entering the tunnel; preferably said device comprising a curved cylinder integrated in one piece.

8) Machine according to one or more of the preceding claims, wherein said second movement speed of the fabric in said tunnel is at least double said first inser- tion/extraction speed of the fabric into/from said accumulation stations, and preferably is at least five times said first speed, and more preferably at least ten times said first speed, and more preferably at least fifteen times said first speed; more preferably said second speed is comprised between five times and thirty times said first speed, and more preferably is comprised between ten times and twenty-five times said first speed, and even more preferably is comprised between fifteen times and twenty times said first speed.

9) Method of drying a continuous fabric in open width, that provides for - inserting, with a first speed, continuously, the fabric arranged in open width, into a initial accumulation station,

alternately moving, with a second speed greater than said first speed, said accumulated fabric, arranging it in open width on a rotating roller, said roller being internally hollow and perforated on the surface, from said initial accumulation station to a final accumulation station and vice versa; during said alternate movement

o striking the fabric from the outside of said roller with a flow of hot air and

o drawing said hot air from inside said roller so that the air from the outside of the roller passes through the thickness of the fabric arranged on said roller, drying it at least partially and maintaining the fabric adhering to said roller,

- continuously extracting said fabric in open width from said final accumulation station, with said first speed,

said fabric being arranged freely on said roller and in said accumulation stations.

10) Method according to claim 9, wherein said second speed is at least double said first speed, and preferably is at least five times said first speed, and more preferably at least ten times said first speed, and more preferably at least fifteen times said first speed; more preferably said second speed is comprised between five times and thirty times said first speed, and more preferably is comprised between ten times and twenty-five times said first speed, and even more preferably is comprised between fifteen times and twenty times said first speed.

1 1 ) Method according to one or more of claims 9 or 10, said roller is adapted to pull said fabric through vacuum pressure created by suction of air from the outside to the inside of the roller, through the thickness of the fabric.

12) Method according to one or more of claims 9, 10 or 1 1 , wherein said flow of hot air that strikes the fabric outside said roller is substantially concordant with, or accompanies, the direction of movement of the fabric adhering to said roller, said flow of hot air reversing its direction when the direction of movement of the fabric adhering to the roller is reversed.