LIKE

Technical Field

The present invention relates to an air-knife dryer, particularly for glass sheets and the like. Background Art

Machines for industrial washing of glass sheets and the like are currently known which are typically divided into a washing area and a drying area. Such machines, which can have a horizontal or vertical working position, can have several dimensions, which are determined by the maximum size of the sheet to be worked and can vary from less than 500mm to more than 4000 mm; the washing machines in practice can process any size of the sheet up to their maximum width. After the washing step, sheet drying is performed by means of rectilinear air-knife blowers, which are supplied with air under pressure along their entire length.

To enable correct operation, an air stream equal to the stream that exits from the knives must reach the inside of the blowers, maintaining an adequate internal pressure in order to sustain the drying air jet.

These known types of dryers are not devoid of drawbacks, which include the fact that if sheets smaller than the maximum size of the machine are treated, energy is wasted.

This is due to the fact that the energy consumption to supply the blowers depends on the size of the dryer and is independent of the size of the sheet being processed, both when the sheet has the maximum dimensions that are acceptable to the machine and when it has the minimum dimensions.

Disclosure of the Invention The aim of the present invention is to provide a dryer, particularly for glass sheets or the like, that makes it possible to save energy in comparison to the background art if the processed sheet is smaller than the maximum acceptable dimensions.

Within this aim, an object of the present invention is to provide a dryer that is structurally simple and economically competitive with respect to the background art.

This aim and these and other objects that will become better apparent hereinafter are achieved by an air-knife dryer, particularly for glass sheets and the like, comprising air blower means for generating at least one pair of mutually opposite air knives which are directed toward at least one sheet to be dried, characterized in that it comprises means for throttling said blower means to adjust the useful width of said at least one pair of air knives. Brief Description of the Drawings

Further characteristics and advantages of the present invention will become apparent from the description of four preferred but not exclusive embodiments, of an air-knife dryer, particularly for glass sheets and the like, according to the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a front elevation view of a first embodiment of an air-knife dryer, particularly for glass sheets and the like, according to the invention;

Figure 2 is a transverse sectional view of the dryer shown in Figure 1, taken along the line H-II;

Figure 3 is a front elevation view of a second embodiment of an air- knife dryer, particularly for glass sheets and the like, according to the invention;

Figure 4 is a transverse sectional view of the dryer shown in Figure 3, taken along the line IV-IV;

Figure 5 is a front elevation view of a third embodiment of an air- knife dryer, particularly for glass sheets and the like, according to the invention; Figure 6 is a transverse sectional view of the dryer shown in Figure 5, taken along the line VI-VI;

Figure 7 is a transverse sectional view of the dryer shown in Figure 5, taken along the line VII-VII; Figure 8 is a front elevation view of a fourth embodiment of an air- knife dryer, particularly for glass sheets and the like, according to the invention;

Figure 9 is a transverse sectional view of the dryer shown in Figure 8, taken along the line IX-IX. Ways of carrying out the Invention

With reference to the figures, the air-knife dryer, particularly for glass sheets and the like, generally designated by the reference numerals Ia, Ib, Ic and Id respectively in its four illustrated embodiments, comprises air blower means 2 for generating at least one pair of mutually opposite air knives 3 which are directed toward at least one sheet 4 made of glass, or other material, to be dried.

According to the invention, in the four illustrated embodiments, the dryer Ia, Ib, Ic and Id comprises means 5 for throttling the blowers 2 to adjust the width of the pair of air knives 3. In order to achieve correct drying of the glass sheet 4, the air knives 3 have an air stream speed and a pressure of impact with the sheet 4 that are substantially equal to predefined values.

With reference to Figures 1 and 2, in the first embodiment Ia the blower means 2 and the throttling means 5 comprise respectively a pair of rectilinear blowers 6, which are arranged opposite each other, and fixed partitions 7, which are arranged inside the rectilinear blowers 2 and at preset distances along the direction of extension of said rectilinear blowers 6 for delimiting two distinct chambers, which can be supplied selectively or simultaneously. More precisely, in this first embodiment the chambers delimited by the partitions 7 are fed independently of each other by the first and second compressed air inlets 8 and 9 arranged at the ends of the rectilinear blowers 6.

In this manner, if a sheet 4 is processed whose dimensions are such as not to affect all the chambers, the supply to the chambers that actually do not contribute to the drying of the sheet 4 is closed.

With reference to Figures 3 and 4, in the second embodiment Ib the blower means 2 and the throttling means 5 comprise respectively the pair of rectilinear blowers 6, which are arranged opposite each other, and movable partitions 11, which can be arranged inside the rectilinear blowers 10 along straight guides 12 which are substantially parallel to the direction of extension of said rectilinear blowers 6 for isolation of at least one sector thereof from the inner air flow.

More precisely, the movement of the movable partitions 11 can, for example, be achieved manually or automatically. In the latter case, it is possible to provide motor means 13 for moving the partitions 11 which comprise, for example, electric motors which are associated with belt transmission means 14, which are connected to the movable partitions 11 and unwind continuously on a driving pulley 10, which is associated with the motor means 13 at a first end of the rectilinear blowers 6, and on a return pulley 16 at a second end of the rectilinear blowers 6, which is opposite to the first end.

With this architecture, the rectilinear blowers 6 can be supplied through a single pair of inlets 15 of compressed air, arranged on one side of the rectilinear blowers 6.

In this manner, if a sheet 4 is processed which is smaller than the maximum dimensions that can be processed by the rectilinear blowers 6, by moving the movable partitions 11 it is possible to isolate the part of the rectilinear blowers 6 that do not contribute to the drying of the sheet 4. With reference to Figures 5, 6 and 7, in the third embodiment Ic the blower means 2 and the throttling means 5 comprise, respectively, the pair of rectilinear blowers 6 arranged opposite each other and flow control elements 17 arranged below the rectilinear blowers 6 at at least one sector of their outlets. In this case also, the movement of the flow control elements 17 can be provided, for example, manually or automatically by way of actuation and selection means 18 for at least partially blocking the discharge ports of the rectilinear blowers 6.

More precisely, the flow control elements 17 comprise substantially L-shaped vanes which are hinged laterally to the rectilinear blowers 6 at the end of the stem of the L-shape for the selective positioning of the foot of the L-shape at the discharge ports of the sector to be blocked.

This movement is allowed by way of the actuation and selection means 18, which can comprise, for example, hydraulic pistons which are operatively connected to the vanes for their rotation and the consequent blocking of the discharge ports of the sector to be blocked by means of linkages 19, which are hinged both to the vanes and to the hydraulic pistons.

With this architecture, the rectilinear blowers 6 can be fed merely by means of the pair of compressed air inlets 15 arranged on one side of the rectilinear blowers 6.

In this manner, if a sheet 4 is processed whose dimensions are smaller than the maximum dimensions that can be processed by the rectilinear blowers 6, by arranging the flow control elements 17 on the discharge ports of the rectilinear blowers 6 it is possible to isolate the part of the rectilinear blowers 6 that do not contribute to the drying of the sheet 4.

With reference to Figures 8 and 9, as regards the last embodiment Id, the blower means 2 can comprise a plurality of pairs of rectilinear blowers

20, which are mutually aligned and arranged mutually opposite, forming distinct chambers that can be supplied selectively or simultaneously. Such chambers can in fact be fed independently of each other through the first and second independent compressed air inlets 8 and 9 arranged at the ends of the rectilinear blowers 20.

In this manner, if a sheet 4 is processed whose dimensions are such as to not affect all the rectilinear blowers 20, the supply of the rectilinear blowers 20 that actually do not contribute to the drying of the sheet 4 is closed.

In a fifth embodiment, not shown, the blowers 2 and the throttling means 5 can comprise respectively the pair of rectilinear blowers 6 and partitions that can be deactivated. Such partitions can be arranged inside the pair of rectilinear blowers 6 to isolate at least one sector of each one of the rectilinear blowers 6 from the internal air stream originating from individual supply inlets 15, one for each one of the rectilinear blowers 6.

More precisely, these partitions which can be deactivated can consist for example of shutters or vanes that can be actuated manually or automatically so as to provide a two-stage valve, which is either fully open or fully closed, inside the rectilinear blowers 6.

The partitions can in fact be inserted or extracted within the rectilinear blowers 6 at right angles to the longitudinal direction of the rectilinear blowers 6, so as to block or free the inner air flow.

As for the second embodiment, with this architecture the rectilinear blowers 6 can be supplied by means of a single pair of compressed air inlets 15 arranged on one side of the rectilinear blowers 6.

In this manner, if a sheet 4 is processed which is smaller than the maximum dimensions that can be processed by the rectilinear impellers 6, by closing the partitions it is possible to isolate the part of the rectilinear impellers 6 that do not contribute to the drying of the sheet 4.

The operation of the air-knife dryer Ia, Ib, Ic, and Id particularly for glass sheets and the like, according to the invention, is evident from what has been described. In practice it has been found that the air-knife dryer, particularly for glass sheets and the like, according to the present invention, fully achieves the intended aim and objects, since it makes it possible to dry glass sheets or the like by throttling the air stream depending on the dimensions of the processed glass sheet.

The air-knife dryer particularly for glass sheets and the like according to the present invention is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

All the details may further be replaced with other technically equivalent elements.

In practice, the materials used, as long as they are compatible with the specific use, as well as the contingent shapes and dimensions, may be any according to requirements and to the state of the art.

The disclosures in Italian Patent Application No. MI2009A000128 from which this application claims priority are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.