COOLER FOR GRANULAR SOLIDS

The present invention relates to a cooler of the type as recited in the preamble of Claim 1 .

In particular, the present invention relates to a device for cooling granular solids and, in particular, powders.

As is known, coolers currently consist of a rotating drum defining an inner chamber to house the granular solids to be cooled; a jet of cold air that cools the granular solids as it flows through the drum; and a rotation apparatus that, by turning the drum, allows the granular solids to be cooled in a uniform manner by the cold air. The prior art described above has a number of significant drawbacks.

A first important drawback consists in the fact that the prior art coolers have a limited cooling capacity and the granular solids must therefore be kept in the drum for a long time.

This aspect is due to the fact that the flow of cold air is only able to cool a limited portion of the inside surface. As a result, the granular solids are almost exclusively only cooled when they come into contact with said limited portion of drum.

Therefore an important drawback consists in the fact that, to achieve adequate cooling of the granular solids, the prior art coolers must be large in size and, in particular, have overall dimensions that can even be more than ten metres.

Another drawback thus lies in the fact that, to cool large volumes of granular solids and, in particular, powders, several coolers and/or very large coolers must be used.

A further drawback is that the known coolers are low in efficiency and thus high in energy consumption. Another no less important drawback lies in the fact that injecting cold air into a rotating drum requires the use of complex solutions which increase the cost of the cooler and are frequently subject to breakdowns as a result of which the cooler must be stopped.

In this situation the technical purpose of the present invention is to devise a cooler for granular solids that substantially overcomes the drawbacks mentioned above. Within the sphere of said technical purpose one important aim of the invention is to provide a cooler that is efficient and, thus, characterised by a high cooling capacity.

Another important aim of the invention is to provide a cooler that is compact in size.

A further aim of the invention is to obtain a cooler for granular solids that is highly efficient and, thus, has low energy consumption.

A no less important aim of the invention is to provide a cooler of simple construction, that is cost effective and highly reliable.

The technical purpose and specified aims are achieved with a cooler as claimed in the appended Claim 1 .

Preferred embodiments are described in the dependent claims.

The characteristics and advantages of the invention are clearly evident from the following detailed description of a preferred embodiment thereof, with reference to the accompanying drawings, in which:

Fig. 1 shows a cooler according to the invention;

Fig. 2 shows a front view of a cooler;

Fig. 3 illustrates a section of an assembly of the cooler; and

Fig. 4 shows a detail of the cooler. In this document, measurements, values, forms and geometric data (such as perpendicularity and parallelism), when used with terms such as "about" or other similar terms such as "practically" or "substantially", are to be considered without any measurement errors or inaccuracies due to production and/or manufacturing errors and, above all, without any slight divergence from the value, measurement, form or geometric data with which they are associated. For example, such terms, when associated with a value, preferably indicate a difference of not more than 10% of said value.

Moreover, terms such as "first", "second", "upper", "lower", "main" and "secondary" do not necessarily indicate an order, priority or respective position, but may simply be used in order to make a clear distinction between the different components. With reference to said Figures, reference numeral 1 globally denotes the cooler according to the invention.

It is suitable for cooling granular solids, that is, bodies with overall dimensions of less than 5 cm and, in detail, less than 1 cm. In particular, it is suitable for use to cool powders preferably consisting of solid particles having a diameter substantially less than 500 pm.

The cooler 1 defines a longitudinal axis 1a and, appropriately, two opposite faces, that is to say a front face 1 b and a rear face 1 c axially spaced with respect to one another.

Note that "axially" and other similar terms such as "axial" define a direction, a length calculated substantially along the axis 1 a.

When the cooler 1 is in use, the longitudinal axis 1 a is substantially horizontal, that is, practically parallel to the supporting surface of the cooler 1 and, thus, substantially perpendicular to the gravitational gradient. The cooler 1 comprises a first drum 2 suitable to receive the granular solids entering the cooler 1 ; a second drum 3 suitable to receive the granular solids in output from the first drum 2 and from which the granular solids leave the cooler 1 ; a first coil 4 enveloping the first drum 2; a second coil 5 enveloping the second drum 3; a cooling liquid passing through the coils 4 and 5; and, preferably, a pipe connecting the drums 2 and 3 suitable to allow the liquid to flow out of the second coil 5 and into the first coil 4.

Preferably, the cooling liquid is water.

The first drum 2 defines a first main barycentric axis of extension practically parallel and, in particular, coincident with the longitudinal axis 1 a.

It is substantially cylindrical and has a ratio of length to diameter that is practically greater than 1 , in detail, substantially comprised between 1 .5 and 3.5 and, more precisely between 2.5 and 3.

The diameter of the first drum 2 is practically smaller than 2.5 m and, in detail, than 2 m and, preferably, substantially comprised between 0.3 m and 1 m.

The length of the first drum 2 is practically greater than 0.5 m and, in detail, than

1 .5 m and, preferably, practically comprised between 2.5 m and 3 m.

As illustrated in Fig. 3, the first drum 2 comprises a first hollow body 21 defining, for the first drum 2, a loading section 2a and an output section 2b of the granular solids; and a first inner auger 22 integral with the inner side surface of the first hollow body 21 and suitable to move the granular solids from the loading section

2a to the output section 2b.

The first body 21 is a hollow cylinder.

The sections 2a and 2b are axially spaced. In particular, the loading section 2a is proximal to the front face 1 b and the output section 2b is proximal to the rear face 1 c (Fig. 3).

The loading section 2a is identifiable in the bottom surface of the first drum 2.

The output section 2b is identifiable in the bottom surface of the first drum 2. Alternatively, the output section 2b (Fig. 3) comprises one or more openings obtained along a ring of the first drum 2 distal to the loading section 2a.

The first auger 22 comprises a helical element extending along the longitudinal axis 1 a and suitable to move the granular solids along said axis 1 a defining a first direction of advancement 2c.

The second drum 3 defines a second main barycentric axis of extension practically parallel to and, in particular, coincident with the axis 1 a.

Preferably, the drums 2 and 3 define barycentric axes of preferred extension substantially coincident with one another and, in detail, with the longitudinal axis 1 a.

The second drum 3 is substantially cylindrical and has a ratio of length to diameter that is practically greater than 1 , in detail, substantially comprised between 1 and 3 and, more precisely between 2.5 and 2.

The diameter of the second drum 3 is practically smaller than 3 m and, in detail, than 2 m and, preferably, substantially comprised between 0.7 m and 1 .5 m.

The length of the second drum 3 is practically greater than 0.5 m and, in detail, than 1 .5 m and, preferably, practically comprised between 2.5 m and 3 m.

The second drum 3 comprises a second hollow body 31 suitable to receive the granular solids in output from the first drum 2 and defining, for the second drum 3, a discharge section 3a of the granular solids; and a second inner auger 32 integral with the inner side surface of the second hollow body 31 and suitable to move the granular solids arriving from the first drum 2 towards the discharge section 3a. The discharge section 3a is proximal to the front face 1 b. It is thus axially distal to the output section 2b and axially proximal to the loading section 2a.

The discharge section 3a is identifiable in a bottom surface of the second drum 3. Alternatively, the discharge section 3a (Fig. 3) comprises one or more openings obtained along a ring of the second drum 3 axially distal to the output section 2a. The second hollow body 31 may have, on the side opposite the loading section 3a and, in particular, in correspondence with the rear face 1 c, a closed base that defines the bottom of the drum 3. Alternatively, the base of the second hollow body 31 may be distal to the open discharge section 3a as shown in Fig. 3.

The second hollow body 31 is a hollow cylinder.

It is suitable to at least partially house the first drum 2 so that the granular solids pass from the first drum 2 to the second drum 3 and, in detail, from the first hollow body 21 to the second hollow body 31 , preferably due to the force of gravity. In detail, the first drum 2 is substantially entirely inside the second body 31 .

The second auger 32 is suitable to move the granular solids from the output section 2b, through which the granular solids pass from the first 2 to the second drum 3, to the discharge section 3a in order to leave the cooler 1 . It thus defines a second direction of advancement 3b of the granular solids that is opposite to the first direction of advancement 2c.

The second auger 32 comprises a helical element integral with the inner side surface of the second hollow body 31 and extending, in the opposite direction to the first auger 21 , substantially along the longitudinal axis 1 a.

The first coil 4 at least partially envelops the outer side surface of the first drum 2, that is, of the first hollow body 21 , so as to come into contact, appropriately directly, with said first body 21 to maximise heat exchange. In particular, it practically totally envelops the outer side surface of the first hollow body 21 .

For the sake of clarity, note that here and in the rest of this document, the outer side surface is the side surface of the drum opposite that to which the auger is attached; whereas the term in direct contact means that said components come into contact with one another without the interposition of other elements.

The first coil 4 has a circular axis of extension substantially coincident with the first barycentric axis of preferred extension and, thus, the axis 1 a.

It is integral with the first drum 2 and, in detail, with the first hollow body 21 .

Preferably, the first coil 4 is a double helix shape so as to have the first inlet mouth 41 and the first outlet mouth 42 of the cooling liquid from the first coil 4 proximal to one another. In particular, the first inlet 41 and outlet 42 mouths are proximal to the rear face 1 c.

The first coil 4 is at least partially and, in particular, substantially completely housed inside the second drum 3.

Lastly, it is suitable to receive the cooling liquid only after it has passed through the second coil 5 as described below.

The second coil 5 at least partially envelops the outer side surface of the second drum 3, that is, of the second hollow body 31 , so as to have the maximum surface in contact, appropriately directly, with said second body 31 , to maximise heat exchange.

In particular, it practically totally envelops the outer side surface of the second hollow body 31.

The second coil 5 has a circular axis of extension practically coincident with the second barycentric axis and, thus, the axis 1 a.

It is integral with the second drum 3 and, in detail, with the second body 31 . Preferably, the second coil 5 is a double helix shape so as to have the second inlet mouth 51 and the second outlet mouth 52 of the liquid from the second coil 5 proximal to one another. In particular, the second inlet 51 and outlet 52 mouths are proximal to the rear face 1 c.

Advantageously, the first mouths 41 and 42 and the second mouths 51 and 52 are proximal to one another, more advantageously, to the rear face 1 c.

The second outlet mouth 52 is placed in fluidic through connection, appropriately by means of said connection pipe, with the first inlet mouth 41 so that the cooling liquid only passes through the first coil 4 after passing through the second coil 5. The drum 1 may comprise a casing 6 suitable to at least partly contain the drums 2 and 3 and the coils 4 and 5; and, in some cases, a support structure 7 suitable to raise the casing 6 and, thus, the drums 2 and 3 and the coils 4 and 5 off the floor. The casing 6 at least partially houses within it the drums 2 and 3 so that the loading 2a and discharge 3a sections and practically all of the coils 4 and 5 are visible.

It comprises a cylinder having an open base through which the loading 2a and discharge 3a sections are visible and, in detail, protrude; and a closed base 61 arranged in correspondence with the rear face 1 c from which at least the second inlet mouth 51 and the first outlet mouth 42 and, in detail, all four of the mouths 41 , 42, 51 and 52, protrude (Fig. 1 ).

Note that, in the case of the second cylinder 31 without the base proximal to the rear face 1 c, the closed base 61 defines the bottom of the second cylinder 31 and, preferably, of the first cylinder 21 , as shown in Fig. 3.

Furthermore, the cooler 1 comprises at least one rotation member suitable to rotate the drums 2 and 3 and, in detail, the coils 4 and 5 about the longitudinal axis 1 a, leaving the casing 6 substantially stationary.

In particular, the cooler 1 may comprise a first rotation member suitable to rotate the first drum 2 and, in detail, the first coil 4 about the first barycentric axis; and a second rotation member suitable to rotate the second drum 3 and, in particular, the second coil 5 about the second axis, appropriately synchronously with the first member.

Preferably, the drums 2 and 3 and, in detail, the hollow bodies 21 and 31 are integral with one another and the cooler 1 comprises a single rotation member 8 suitable to simultaneously rotate at least the drums 2 and 3 substantially about the axis 1 a.

Said constraint between the drums 2 and 3 is achieved by the second auger 32 which is integral with the first hollow body 21 .

The rotation member 8 is suitable to rotate the drums 2 and 3 and the coils 4 and 5 leaving the structure 7 practically stationary. Alternatively, it also leaves the casing 6 stationary.

The rotation member 8 illustrated in Fig. 2 comprises at least a motor 81, preferably an electric motor; a kinematic mechanism 82, such as a friction wheel, suitable to exploit the motion of the motor 81 to make the drums 2 and 3 and, preferably, the coils 4 and 5, rotate about the longitudinal axis 1 a.

In addition, the rotation member 8 may comprise an idle support 83, for example a bearing, suitable to idly support the second drum 3.

Lastly, the cooler 1 may comprise at least one hydraulic rotary joint 9 suitable to permit the passage of liquid between a fixed structure, in this case an external supply network, and a rotating structure, in this case the coils 4 and 5; and, preferably, connection pipes suitable to place the rotary joint 9 in fluidic through connection with an external network and with the coils 4 and 5.

In detail, it comprises a single rotary joint 9 suitable to allow the liquid to enter the cooler 1 and, thus, to enter the first coil 4 and to allow the liquid to flow out of the cooler 1 and, thus, out of the second coil 5.

The rotary joint 9 illustrated in Fig. 4, comprises a stator 91 suitable to be placed in fluidic through connection with the external network; a rotor 92 suitable to be placed in fluidic through connection with the coils 4 and 5; and, appropriately, sealing means suitable to prevent leakages of liquid in particular during the passage between the rotor 92 and the stator 91 .

The stator 91 is suitable to remain stationary during the operation of the cooler 1 whereas the rotor 92 is suitable to rotate about the longitudinal axis 1 a. In particular, the stator 91 is integral with the support structure 7, whereas the rotor 92 is integral with the drums 2 and 3. More in particular, the rotor 92 is integrally connected to the casing 6 and, thus, to the drums 2 and 3.

The stator 91 comprises a body in which there are obtained a central stator duct 911 substantially extending along the longitudinal axis 1 a; a lateral stator duct 912 comprising, for example, a ring having an axis practically coincident with the longitudinal axis 1 a.

The stator ducts 91 1 and 912 are suitable to be placed in fluidic through connection with the external network to allow the cooling liquid to flow into and out of the cooler 1 .

The central stator duct 91 1 comprises a cylindrical duct having an axis practically coincident with the longitudinal axis 1 a.

The lateral stator duct 912 comprises a ring having its axis practically coincident with the longitudinal axis 1 a. The stator 91 further comprises connectors suitable to place the stator ducts 91 1 and 912 in fluidic through connection with the external network.

The rotor 92 is suitable to rotate, preferably idly, with respect to the stator 91 about the longitudinal axis 1 a.

It comprises a body in which there are obtained a central rotor duct 921 in fluidic through connection with the central stator duct 91 1 ; and a lateral rotor duct 912 is in fluidic through connection with the lateral stator duct 912.

The central rotor duct 921 substantially extends along the longitudinal axis 1 a. It comprises a cylindrical duct having an axis practically coincident with the longitudinal axis 1 a.

The lateral rotor duct 922 comprises a ring having an axis practically coincident with the longitudinal axis 1 a.

Furthermore, the central rotor duct 921 and the lateral rotor duct 922 are in fluidic through connection one with the second inlet mouth 51 and the other with the first outlet mouth 42.

The functioning of a cooler, described above in a structural sense, is as follows. Initially, a granular solids discharge duct is arranged in correspondence with the loading section 2a and an external network is connected to the rotary joint 9 so as to allow a cooling liquid, appropriately water, to pass through the second coil 5 and, only then, through the first coil 4.

Furthermore, the rotation member 8 makes the drums 2 and 3, the coils 4 and 5, the casing 6 and the rotor 92 rotate, substantially about the longitudinal axis 1 a, leaving the structure 7 and the stator 91 substantially stationary.

At this point, the granular solids, in output from the discharge duct, enter the first drum 2 through the loading section 2a. They fall onto the inside surface of the first hollow body 21 where they are received by the first inner auger 22.

Thus the first auger 22, which is integral with the first hollow body 21 , rotates about the longitudinal axis 1 a and pushes the granular solids along the axis 1 a, in the first direction of advancement 2c, and towards the output section 2b.

As the granular solids advance along the inside surface of the first hollow body 21 , the cooling liquid passing through the first coil 4 cools the first hollow body 21 and, thus, the granular solids passing over it.

The granular solids reach the output section 2b from where they pass owing to the force of gravity into the second hollow body 31 .

Here, the granular solids are received by the second auger 32 which moves them in the second direction of advancement 3b, that is, in the opposite direction to the first direction of advancement 2c.

Therefore, the granular solids slide along the inside surface of the second hollow body 31 and, when they arrive at the discharge section 3a, they leave the second drum 3 and, thus, the cooler 1 , owing to the force of gravity.

Lastly, as the granular solids slide along the inside surface of the second hollow body 31 they are cooled by the second coil 5 and, precisely, by the cooling liquid which, since it has not yet passed through the first coil 4, is at a lower temperature than the cooling liquid passing through said first coil 4.

The invention achieves some important advantages.

A first important advantage lies in the fact that the cooler 1 has a high cooling capacity compared to those known in the prior art and the granular solids are thus cooled more quickly.

This aspect is due to the fact that since the coolant is a liquid, it is able to accumulate heat without heating as quickly as a gas. This aspect is enhanced by the use of a cooling process performed in two sequential stages, one in the first drum 2 and one in the second 3.

The use of two drums 2 and 3 allows the cooling liquid to cool the granular solids while they pass through the first drum 2 and the second drum 3 without becoming too hot and, thus, always remaining at a low temperature with a high cooling capacity.

Owing to this greater efficiency, the cooler 1 cools faster than the coolers of the same size currently available on the market.

A further advantage thus consists in the lower energy consumption of the cooler 1 compared to the known systems.

Modifications and variations may be made to the invention described herein without departing from the scope of the inventive concept as expressed in the independent and dependent claims. All details may be replaced with equivalent elements and the scope of the invention includes all other materials, shapes and dimensions.