DESCRIPTION

The present invention relates to a dryer for garments.

Two types of rotary drum dryers are known for the industrial drying of garments: fixed and/or tilting front dryers and pass-through dryers.

A front dryer has one front opening that provides access to a rotary drum. The garments are introduced in the dryer through the front opening, which is successively closed. The rotary drum with the garments rotates in a hot-dry environment, drying the garments. When the drying process is completed, the dryer is tilted, the opening is opened and the garments are unloaded from the front opening of the dryer.

A pass-through dryer comprise a rotary cylinder with an inlet opening and an outlet opening disposed at the two ends of the cylinder. The garments are introduced in the rotary cylinder through the inlet opening. The two openings are closed with lids and the cylinder is rotated. The garments remain in the dryer for the time necessary for drying. When the drying process is completed, the rotation of the cylinder is stopped, the cylinder is tilted and the lid of the outlet opening is opened in order to unload the garments from the outlet opening.

In both types of dryers, drying is not continuous, meaning that a lot of garments remains in the dryer until all garments are dried and then the lot of garments is unloaded from the dryer.

The permanence time of each lot of garments in the dryer is controlled by means of a timer and/or temperature probes. The timer is empirically set according to the experience of the operator. The temperature probes measure the temperature of the garments and inform the operator when the garments are dry and are to be unloaded from the dryer. Both control systems are impaired by some drawbacks. The timer is not reliable because water can remain in the garments even after the preset time has elapsed. The temperature probes may feel the heat of the cylinder or drum, which is very hot, and give incorrect information. In such a case, it is necessary to stop and restart the machine.

US4015930 discloses a laundry dryer according to the preamble of claim 1.

The purpose of the present invention is to eliminate the drawbacks of the prior art by providing a dryer for garments that is suitable for operating continuously, is efficient, effective, versatile, compact and reliable.

These purposes are achieved according to the invention with the characteristics of the independent claim 1.

Advantageous embodiments of the invention appear from the dependent claims.

The dryer for garments according to the invention is defined in claim 1.

Additional features of the invention will be clearer from the following description, which refers to a merely illustrative, not limiting embodiment, as shown in the appended figures, wherein:

Fig. 1 is a perspective view of the dryer according to the invention;

Fig. 2 is an axial sectional view of the dryer of Fig. 1 ;

Fig. 3 is a perspective view of a back portion of the dryer, which shows an unloading device;

Fig. 4 is a partially interrupted, perspective view of the unloading device in the proximity of the outlet of the drying chamber;

Fig. 5 is a perspective view of the drying chamber, which shows the rotary cylinder;

Fig. 6 is a perspective view of a front portion of the drying chamber; Fig. 7 is a perspective view of the drying chamber, which shows the fan and indicates the air flows;

Figs. 7 and 8 are perspective views that show the weighing means of the inlet conveyor and of the outlet conveyor;

Figs. 9 and 10 are perspective views of the weighing means of the rotary cylinder.

With reference to the Figures, the dryer according to the invention is disclosed, which is generally indicated with reference numeral 100.

With reference to Figs. 1 and 2, the dryer (100) comprises an inlet conveyor (1 ), a drying chamber (2) and an outlet conveyor (3).

The drying chamber (2) has an inlet (20) that is continuously fed with the wet garments from the inlet conveyor (1 ), and an outlet (21 ) that continuously unloads the dry garments that are continuously fed on the outlet conveyor (3) by means of an unloading device (4) disposed in the outlet (21 ) of the drying chamber.

The inlet conveyor (1 ) has a first horizontal section (10) and a second upward-inclined section (1 1 ) that ends in the inlet (20) of the drying chamber.

The outlet conveyor (3) has an upward-inclined section (30) that ends in a container (not shown) where the dry garments are collected.

With reference to Figs. 3 and 4, the unloading device (4) comprises a rotary shaft (40) disposed with horizontal axis in the outlet (21 ) of the drying chamber at a lower height with respect to the center of the outlet.

Blades (41 ) shaped as longitudinal plates protrude radially from the rotary shaft (40) in such a way that a housing suitable for receiving at least one garment, preferably one or two garments, is formed between two blades (41 ).

Actuation means (42) drive the rotary shaft (40) in rotation. The actuation means (42) may be an electric motor. A transmission (43) transmits the motion from the actuation means (42) to the rotary shaft. The transmission (43) can be a belt transmission that is engaged in pulleys.

The unloading device (4) takes the garments from the outlet (21 ) of the drying chamber and unloads the garments on the outlet conveyor (3), for example one garment or two garments at a time. For illustrative purposes, the unloading device (4) may comprise four blades (41 ) arranged at 90°. In view of the above, four or eight garments are unloaded on the outlet conveyor (3) at every complete revolution of the rotary shaft (40).

With reference to Figs. 2 and 5, a rotary cylinder (5) is revolvingly mounted in the drying chamber (2). The rotary cylinder (5) is open in the front and in the back in such a way to communicate with the inlet (20) and with the outlet (21 ). In particular, the inlet (20) ends into an inlet conduit (22) that is inclined downwards and is in communication with a front opening (50) of the rotary cylinder (5). A back opening (51 ) of the rotary cylinder is disposed in correspondence of the outlet (21 ) of the drying chamber.

The rotary cylinder (5) has a lateral wall with a plurality of holes (52). A plurality of blades (53), which consist in longitudinal strips that are fixed to the internal wall of the cylinder, is disposed inside the rotary cylinder.

With reference to Figs. 5 and 6, two circular guides, which are shaped as annular collars, are mounted on the external lateral wall of the rotary cylinder, protruding externally from the rotary cylinder. Each circular guide (54) is disposed in intermediate position between a center of the cylinder and an end of the cylinder.

The circular guides (54) are supported on wheels (60) or rollers in such a way to support the rotary cylinder. The wheels (6) are mounted on two shafts (6) with axes that are parallel to the axis of the rotary cylinder and are disposed on both sides with respect to the axis of the rotary cylinder. Although the figures show one side of the drying chamber, and therefore one shaft (6) only, when looking at the rotary cylinder (5) from the front, one shaft is provided on the left-hand side and one shaft is provided on the right-hand side with respect to the axis of the rotary cylinder. Evidently, the distance between two shafts (6) is lower than the diameter of the rotary cylinder (5). The shafts (6) are revolvingly supported by a frame (T).

With reference to Fig. 6, the shafts (6) are fixed to pulleys (61 ) disposed in a front portion of the drying chamber. The pulleys (61 ) are moved by an electric motor (62) by means of a belt transmission (63).

The wheels (60) are fitted on the shafts (6). The wheels (60) are made of a material that generates friction with respect to the circular guide (54) of the rotary cylinder. In view of the above, a rotation of the wheels (60) determines a rotation of the rotary cylinder.

With reference to Fig. 5, the back opening (51 ) of the rotary cylinder is disposed in a back panel (23) of the drying chamber. The back panel (23) is mounted on hinges (24) with an axis of horizontal rotation under the rotary cylinder (5). In this way, the inclination of the rotary cylinder can be varied with respect to a horizontal axis, rotating the back panel (23) around the axis of the hinges (24).

The dryer comprises adjustment means (8) to adjust the inclination of the rotary cylinder (5).

The adjustment means (8) comprise a linear actuator (80) disposed under the rotary cylinder (5) in proximal position to the front opening (50) of the rotary cylinder. The linear actuator (80) may be a hydraulic cylinder-piston assembly. The linear actuator (80) is fixed to the frame (T) and has one piston connected to the rotary cylinder (5) and an axis of vertical actuation. In view of the above, the inclination of the rotary cylinder can be varied with respect to a horizontal axis by means of the actuator (80), according to the desired forward traveling speed of the garments.

The garments are moved forward in the rotary cylinder (5) in a levelled way with a continuous introduction of wet garments. In fact, the wet garments are disposed in the front of the rotary cylinder, whereas the dry garments are disposed in the back of the rotary cylinder.

In any case, the downward inclination of the rotary cylinder from the inlet to the outlet can be increased or decreased by means of the adjustment means (8); respectively, if the garments are moved too slowly and consequently the dry garments are piled up inside the rotary cylinder, or if the garments are moved too fast and consequently they are still wet when they are unloaded.

Infrared sensors are disposed inside the rotary cylinder (5) to measure the temperature of the garments inside the rotary cylinder. In this way, according to the measured temperature, the linear actuator (80) can be actuated to vary the inclination of the rotary cylinder and the forward traveling speed of the garments.

With reference to Fig. 7, the dryer (100) comprises a fan (7) and a heat exchanger (E) disposed in the drying chamber (2). The fan (7) is actuated by an electric motor (70) by means of a transmission (71 ). The fan is disposed in the drying chamber above the rotary cylinder (5). The electric motor (70) is disposed outside the drying chamber.

The drying chamber (2) comprises:

- a front compartment (26) disposed under the heat exchanger (E),

- a front-upper compartment (27) disposed above the heat exchanger (E) and in front of the fan (7),

- an upper compartment (28) disposed behind the fan (7) and above the rotary cylinder (5), and

- a lower compartment (29) disposed under the rotary cylinder (5). The fan (7) extracts air from the front compartment (26) in such a way that the air that passes through the heat exchanger (E) is heated, reaching the front-upper compartment (27). Then, hot air is extracted by the fan (7) from the front-upper compartment (27) and is introduced in the upper compartment (28). The hot air passes through the holes (52) of the rotary cylinder and is introduced in the cylinder to dry the garments. Therefore the air is loaded with humidity.

The humid air flows in the lower compartment (29) and is extracted in the front compartment (26) in order to restart a new circulation.

With reference to Figs. 8 and 9, first weighing means (C1 ) are disposed in the inlet conveyor (1 ) to weigh the garments disposed on the inlet conveyor. Second weighing means (C2) are disposed in the outlet conveyor (3) to weigh the garments disposed on the outlet conveyor.

The inlet conveyor (1 ) and the outlet conveyor (3) are mounted on frames (14, 34) supported by legs (15, 35) that rest on the ground.

The first weighing means (C1 ) are load cells mounted in the lower end of the legs (15) of the inlet conveyor in order to measure the weight of the wet garments that are introduced in the drying chamber. The load cells of the first weighing means (C1 ) are set in such a way to subtract the tare relative to the weight of the inlet conveyor from the measured gross weight, in such a way to calculate the net weight of the garments on the inlet conveyor.

The second weighing means (C2) are load cells mounted in the lower end of the legs (35) of the outlet conveyor in order to measure the weight of the dry garments disposed on the outlet conveyor. The load cells of the second weighing means (C1 ) are set in such a way to subtract the tare relative to the weight of the outlet conveyor from the measured gross weight, in such a way to calculate the net weight of the garments on the outlet conveyor. With reference to Figs. 10 and 1 1 , third weighing means (C3) are disposed in the drying chamber in order to weigh the garments contained in the rotary cylinder (5).

An actuator (9) is fixed to the frame (T) of the drying chamber under each circular guide (54) of the rotary cylinder. Each actuator (9) is connected to an arched support (90) with the same radius of curvature as the circular guide (54). When the actuators (9) are actuated, the arched supports are engaged with the circular guides (54) and the rotary cylinder is raised.

The third weighing means (C3) are load cells and are disposed between each actuator (9) and the arched support (90) in order to measure the weight of the garments in the rotary cylinder (5). The third load cells of the third weighing means (C3) are set in such a way to subtract the tare relative to the weight of the rotary cylinder from the measured gross weight in such a way to calculate the net weight of the garments inside the rotary cylinder.

The dryer (100) of the invention provides for the following checking operations:

- Checking the inclination of the rotary cylinder (5), by means of the adjustment means (8) in order to adjust the forward traveling speed of the garments in the rotary cylinder.

- Checking the rotational speed of the unloading device (4) according to the forward traveling speed of the garments in the rotary cylinder, and checking the number of garments that are introduced in the unloading device (4).

- Checking the weight of the garments on the inlet conveyor (1 ) and in the rotary cylinder (5) by means of the first weighing means (C1 ) and the third weighing means (C3) in order to synchronize the speed of the inlet conveyor (1 ) with the forward traveling speed of the garments in the rotary cylinder (5); in this way, it is possible to define the quantity of garments to be introduced in the rotary cylinder based on the measured weights and an alarm is generated to inform the operator when the inlet conveyor (1 ) is overloaded with wet garments.

- Checking the humidity produced in the drying chamber. The quantity of humidity produced in the drying chamber is calculated by subtracting the weight of the wet garments on the inlet conveyor and the weight of the dry garments on the outlet conveyor. The humidity produced in the drying chamber is discharged according to the calculated humidity.

Moreover, the following parameters are checked based on the humidity calculation:

- the rotational speed of the fan (7),

- the rotational speed of the rotary cylinder (5) and

- the opening and closing of extraction slots in the drying chamber to increase and/or decrease the air flow.

Otherwise said, the dryer (100) has a control unit that is configured in such a way to calculate the humidity contained in the drying chamber (2) according to the weight measured by said first, second and third weighing means (C1 , C2, C3) and accordingly adjust the rotational speed of the rotary cylinder (5), the rotational speed of the fan (7) and the opening/closing of extraction slots in the drying chamber in order to increase/decrease the air flow.