ITMI20002508A1 - PROCEDURE AND DEVICE FOR THE DRY SEPARATION OF THE LIGHT AND HEAVY FRACTIONS OF A PRE-SELECTED GRANUL BUILDING MACERIE - Google Patents

Abstract

A method and device for separating light fractions, in particular longitudinally extending wood (27), from granulometrically sieved rubble mixtures (9), in which on a vibrating panel (3), are arranged a plurality of partition walls (7) defining channels (8) for orienting and longitudinally guiding the rods (27), where is provided a variable size composite opening (13) allowing to from a first curtain (21) comprising the heavy fractions and smaller light fractions, and a second curtain (24) formed by light paper and larger synthetic sheet material fractions and wood "rods" (27) or only by the latter. The subject separating device (1) can be used as an end separating stage, and can practically provide a recovery of the actual end weight due to the residual presence of the light fraction comprising the wood rods (27) to prevent any disposal of in disposal sites, since the rods (27) are cleaned and accordingly can be reused. Moreover, the end inert material, after the above mentioned operation, is cleaner and has an improved value.

Description

Even the final inert material will be cleaner and more enhanced after this operation.

(Figure 2)

Description of the finding

The present invention relates to a method and a device for the dry separation of the light and heavy fractions of a granulometrically preselected mixture of building rubble, according to the preambles of claims 1 and 6 respectively.

As is known, in the treatment of building rubble mixtures aimed at obtaining mainly recycled inert materials for their use in place of natural quarry aggregates, it is extremely important to reduce as much as possible the presence of light traction components (wood, paper, plastic material, etc.), from the components of the fractions of heavy materials, forming said recycled aggregates (cement agglomerates, tiles, marbles and so on).

These separations can be carried out wet or dry. Wet separation, or by flooding, is usually used in the Netherlands, for example, which practically do not have quarries, so that the inert materials from rubble or recovery are also used for the most qualitative uses and which require practically a total absence. of light fractions. Large quantities of water are required and furthermore the treatment equipment and operating costs are very high. With the current dry treatments for the separation of light and heavy fractions from mixtures of building rubble it is possible to obtain, for example in pre-selected mixtures with a particle size of 30/70 mm, a residual weight of light fraction greater than 0.4% . This value is considered high.

With the present technology of the applicant it is possible to further reduce this residue by weight of light fraction up to 0.2%. It would be extremely desirable to be able to further reduce this percentage in order to considerably improve the characteristics of the recovered aggregates obtained.

The inventor observed that in the pre-selected mixtures the residue by weight of the light fractions at the end of the treatment cycle consists mainly of "stick" pieces of wood which in the preliminary passage of the rubble through the crushing mill are derived from doors, windows and the like, or have been detached from these, generally along the direction of the wood grain and in correspondence with the knots and thus take on conformations with a length of, for example, from about 10-12 cm to 20 cm and more with small irregular cross sections , or rather like "sticks". Unlike the components of the heavy fraction, which have a conformation in the form of gravel or scree, or in irregular shapes more or less ovoid, in the "sticks" of wood the differences between the transverse and longitudinal dimensions are considerable, so that through a selection hole with a diameter of, for example, 60 mm can also pass “sticks” with a length of 15 - 20 cm.

Therefore it has not been possible up to now, with dry separation procedures, to separate said "sticks" using the known vibrating surfaces with through holes or with elastic lamellae with dimensions for the desired granulometry from time to time, for example 30/70 mm; nor with blowers or vacuums, except for the use of considerable power, with which, however, the brick parts, that is heavy, are also blown away or sucked up.

The aim of the present invention is to indicate a process and a separation device of the type indicated, capable of further decreasing the residual weight of the light fraction in the separated inert fraction to values lower than the current 0.2%. .

This task includes obtaining the indicated result in the presence of a completely irrelevant energy consumption and without requiring any modification of the currently known dry treatment plants.

The indicated task is solved, according to the invention, with a process and a device respectively which have the characteristics of claims 1 and 6 respectively.

Further developments and advantageous features of the process and of the device according to the invention are indicated in the dependent claims.

Numerous and important advantages are achieved with the method and the device according to the invention.

In the first place, the proposed method and device allow to reduce the weight residue in a light fraction to a considerable extent below the value of 0.2% currently achievable, for example to an extent of the order of 50% or more of said value, that is, until a residual percentage of less than 0.1% is obtained, as noted in the course of various practical examples. A further advantage is that these results can be achieved automatically, ie without the use of labor to preliminarily remove the light fraction, as instead provided for in the "Dutch" separation treatment or by flooding.

The continuous action of moving forward with shocks exerted on the sticks in the longitudinal direction of the vibrating plane and thrusting on the sticks in the direction of longitudinal advancement, exerted on the sticks by the heavier pieces, often advancing more rapidly, in the presence of wedge-shaped invitation sides of the walls dividers, guarantee an advantageous and reliable pre-orientation of the poles. In this way, transversal positioning of the sticks is avoided, for example against the dividing walls, in the manner of "barricades", which would cause a barrier and stop of the advancement of the mixture in the orientation corridors.

The desired separation operation of the sticks is achieved in a reliable and automatic way by means of an elastically flexible edge, for example of rubber or the like, with a flexibility that allows it to be non-deformable when light wooden sticks pass over it and, at the same time, its inflection under the weight of the heavier and larger pieces resting on it, with the consequent gravity fall of said heavy pieces through the composite opening with variable span.

With the teaching of the invention it is also advantageously possible to obtain a light fraction formed only by longer wooden sticks, or composed only by sticks, which are clean and therefore no longer have to be disposed of in landfills but can in turn be used for other uses, for example advantageously for the production of industrial chipboards, cellulose, paper and so on.

The provision of a large area for receiving the rubble mixture allows a reliable distribution of the mixture substantially in a thin layer, i.e. in the form of a single-layer mixture, which facilitates the longitudinal self-movement of the sticks even with a feed of the rubble mixture carried out with traditional conveyor belts or chute channels, relatively narrow.

An advantageous sizing of the separator device according to the invention is also indicated below in order to obtain high separation efficiency.

With a pneumatic separation of the smallest light fractions, per se known in the field, and which can be carried out upstream or downstream of the device according to the invention, a fraction of heavy materials, i.e. of inert materials, practically free of materials is obtained. of the light fractions, which is thus of greater commercial value.

Further features, advantages and details of the process and of the device according to the invention can be seen from the following description of an example of a preferred embodiment of the invention, with reference to the attached drawings, in which they schematically show:

Figure 1 is a plan view of the device for dry separation of the light and heavy fractions of a mixture of building rubble; Figure 2 shows a longitudinal section along the plane II-II of Figure 1;

figure 3 shows a cross section along the line ΙΙΙ-ΙΙΙ of figure 2;

figure 4 shows a detail on an enlarged scale of the terminal part of the device with variable opening discharge opening, e

Figures 5 and 6 illustrate different instantaneous situations of discharge respectively of the first and second curtain of separate materials. With reference to the figures indicated above, in which like parts have the same reference marks, the separation device according to the invention is indicated as a whole with 1. It comprises a case 2 and a vibrating plane 3, to which, according to the invention, vibrations are imparted to and fro in a substantially coplanar plane, by means of a vibration assembly, not illustrated, comprising lateral vibrators, also not illustrated and of any execution. , where reference 6 indicates stiffening ribs adapted to support said vibratory motions. The vibrating screen advancement plane 3 can be realized in any suitable way, for example as a vibrating feeder, vibrating channel and so on. Number 5 indicates hinging holes in a supporting structure, not shown in detail, for an adjustment of the downward inclination of the vibrating plane 3 according to the composition, humidity, etc. of the mixture of debris fed, or other operating parameters. According to the invention, a plurality of strip partition walls 7 are arranged on the vibrating plane 3, arranged in a longitudinal direction and spaced apart from each other, in the illustrated example five partition walls 7 forming six orientation channels 8 which, in the illustrated example, have a increasing width in the direction of transport of the mixture. Upstream of the dividing walls 7 (with reference to the direction of advancement F of the rubble on the vibrating plane 3) on the vibrating plane 3 there is a first part 12 for feeding and widening / leveling the mixture of rubble 9, fed through a channel conveyor belt 11 as usual, having a width of, for example, 30 cm, supported by lateral supports 4. In the illustrated example, the rubble stream 9 falling from the belt or channel 11 forms a curtain of rubble 9A, to which a device 10 for pneumatic removal of the lighter parts of the wooden sticks, for example a blower or an aspirator, said light parts removed and then collected separately, in a per se known manner. Said removal will be activated according to the desired characteristics of the aggregates and the fraction of sticks, in combination or not with other pneumatic removals downstream of the light parts, described below.

The aforementioned feeding and leveling area 12 is preferably formed by a metal surface and / or by a coating of any other material having a high sliding coefficient to achieve an effective and rapid leveling and advancement action of the various pieces of the blend. A suitable coating can consist, for example, of rubber, polyurethane or the like, having a high sliding coefficient.

As can be clearly seen from the drawings, in correspondence with the final portion of the dividing walls 7 there is a composite transversal opening with variable span 13, which is formed by a free opening 14, of length 14A, and by a downstream edge (again with reference to the direction of advance F of the rubble mixture) indicated with 16, of length 16A, and formed by a strip of elastically flexible material such as rubber or synthetic material, fixed - along its opposite edge to the free opening 14 to the vibrating plane 3, by gluing, screws or any other suitable way. The total length of the variable opening 13 will therefore be 13 A = 14A 16A, whereas the useful drop length of said composite variable opening 13 will in practice be less, depending on the elasticity of the flexible edge 16, i.e. of its folding inside the opening 13, as mentioned in fig. 5, under the weight of the respective heavy piece 22.

The flexible edge 16 is elastically yieldable under the weight of the pieces 22 larger than the heavy fraction of the rubble and is instead substantially stable under the light weight of the wooden sticks 27 or other larger pieces 26 of paper and plastic. The elasticity characteristics of the flexible edge 16 must therefore be adapted to the particle size of the mixture to be treated from time to time. Said flexible edge 16 can therefore advantageously be provided to be replaceable.

In the example illustrated, the dividing walls 7 terminate downstream of the composite opening 13 with variable span and, starting from their downstream edge 17, the end portion 18 of the vibrating plane 3 is provided inclined downwards and ends with the edge transverse 19.

With the structure described, the composite opening with variable span 13 constitutes the fall opening of a first mixed curtain 21 comprising the heavy components 22 and the components 23 of the smallest light fractions, that is, passing through the free opening 14. The parts of the larger light fractions, pieces of paper, of synthetic material leaf and the sticks, which actually go beyond the free opening 14, and go beyond it in the manner of a mobile "bridge" leaning on the flexible edge 16, form a second curtain 24, the which is therefore formed by only light fractions comprising pieces of paper and synthetic material 26, as well as wooden sticks 27, in the event that the pneumatic separation of the light parts upstream, or exerted on the fed rubble stream 9, has not been activated.

As can be seen in particular from fig. 2 furthermore, the front impact side 28 of the walls 7 is made oblique in the manner of a lifting and rotating invitation side for the sticks 27. The height of the dividing walls 7 will generally be greater than the largest particle size of the rubble mixture 9 to be treated. , for example 100 mm in the case of a grain size of 30-70 mm. Therefore the sticks 27 which with one of their parts or ends are urged to slide and rise on said lead sides 28 during their advancement will tend, as they fall from said oblique lead side, to arrange themselves more or less on the vibrating plane 3. less longitudinal.

Relative to the length of the strip or flexible edge 16, it, according to the invention, is for example between 50% and 100% of the width of the free opening 14.

With reference to a granulometry of the mixture of rubble to be treated of 30/70, a preferred embodiment of the separator 1 according to the invention presents, by way of example, the following sizing:

a: width of the vibrating table 3 = 600 mm

b: total length of the vibrating table 3 = 1.180 mm

c: length of the monolayer leveling portion 9 of the feed mixture 9 = 400 mm

d: length of the partition walls 7 = 780 mm

e: length of the inclined end portion 18 of the vibrating plane 3 = 134 mm

f: total length 13A of the composite opening with variable span 13 = 100 mm

g: length 14A of the free opening 14 = 60 mm

h: length 16A of the elastic edge 16 = 40 mm

i: height of the partition walls 7 = 100 mm

j: initial width of the orientation channels 8 = 120 min

j ': final width of the orientation channels 8 = 150 mm

k: vibrating unit suitable for generating substantially coplanar back and forth vibrations,

1: difference in height S between the vibrating surface 3 and the underlying flexible edge 16 = 8 mm.

According to the invention, in addition to the rubble curtain 9A, a pneumatic device is preferably associated with the first and / or second curtain 21, 24, for example a blower or aspirator 29, for moving away from said first and / or second curtain. 21 and 24 of the light fractions of pieces of paper, synthetic leaf, small pieces of wood and the like. The operation of the separator device 1 according to the invention, referred to in part above, is as follows:

the curtain 9 A of mixture of rubble 9 is made to fall on the leveling portion 12 of the vibrating plane 3. The dusty part has been previously removed. The individual different typological pieces, mentioned for example with 22, 23, 26, 27, forming the mixture 9, when falling on the initial portion 12 of the vibrating belt 3, undergo a widening or leveling action following both the impact on a surface with high sliding coefficient which due to their relative rolling movements one above the other upon falling and favored by substantially coplanar vibrations, which tend to move said individual pieces apart, further flattening possible due to the considerable width provided for said portion 12. When said pieces of the mixture 9 reach the orientation channels or corridors 8, the parts of the heavier fractions are dragged or slide in said channels 8, either directly or after partial rotation on themselves in case of impact with the leading edges 28 of the dividing walls 7. The sticks 27, due to their considerable length, reach more easily either before or after in contact or with the leading edges 28 or the dividing walls 7 themselves and, following the combined advancement action exerted on the sticks by the vibrating plane 3 and by the adjacent moving parts of the heavier fractions 22, said sticks receive an orientation action and guides in the longitudinal direction when they enter and / or travel through said orientation and guide channels 8, with possible lifting, rotation and fall, as mentioned above. The conditions for approaching said sticks 27 to the free opening 14 are thus created with a substantially orthogonal position with respect to the latter. In these conditions, the sticks 27 tend to overcome, first by cantilevering and then as a mobile "bridge", the free opening 14 without any downward inclination of their front end jeopardizing the overcoming of said free opening 14 and the subsequent support with their front end on the edge or flexible strip 13, equally vibrating with the surface 3. The sticks 27 are thus further dragged towards the falling edge 19 of the final section 18 of the vibrating surface 3. A similar behavior can be found in the pieces 26 of paper or synthetic leaf of a length greater than the length of the free opening 14. In this way the sticks 27 and the larger pieces of paper and plastic sheet 26 form the second curtain 24 comprising only materials extended in length of the light fractions.

On the other hand, all the pieces of the heavier fractions fall either directly through the free opening 14 or if they, like the pieces 22, have the largest dimensions of the particle size considered (for example 30/70 min), with their weight falling into the free opening 14 and resting on the flexible edge 16, will cause a bending or inflection of said edge 16 thereof downwards. In this way, the falling surface of the composite opening with variable span 13 will increase and the larger heavy pieces 22 will fall, possibly together with other smaller pieces of the incoming light and heavy fractions, to form a first curtain 2 1, which will be of mixed type - in the case in which the pneumatic separation on the curtain of rubble 9A has not been activated - as it includes materials of both heavy fractions 22 and light fractions 23.

The phases of falling or transit of the pieces of light and heavy components illustrated above individually and in a given instant can obviously be carried out in practice both separately and in common, depending on the random arrival of the various components of the mixture 9 at the slot variable light composite 13.

In order to avoid that a large heavy piece 22 causing a bending of the edge 16 also entails the possible concomitant fall into the opening 13 with variable span of sticks 27 at the moment also present, according to the invention the flexible edge 16 can be cut longitudinally with cuts 31 , defining a plurality of adjacent flexible tabs 32 independently of each other. This expedient will significantly improve the efficiency of the separation and the amount of sticks present in the first curtain 21 will be completely irrelevant.

A pneumatic removal of the lighter pieces of paper or synthetic sheet 23, 26 can also be advantageously provided by adopting, as known per se, units of blowers or aspirators 29, Figures 5 and 6 with retative collection means 29A, where the arrows indicate the transport direction of the light fractions taken.

By using the blowers or fans 10 and 29 it is possible to advantageously obtain an inert material 33 practically free of light fractions and / or a collection of rods 34 which are also practically clean and free from other light fractions of paper or synthetic material. In this way, the commercial value of the aggregate obtained can be significantly increased and at the same time the cleaned wooden sticks, instead of having to be taken to the landfill, can be sent to the production of cellulose, paper, chipboards for industrial use and so on. . The activation of the pneumatic removals at the rubble curtain 9A and the first and second curtain 21 and 24 in a single or combined way as desired will depend both on the compositions of the rubble mixtures 9 as well as on the degree of purity desired in the aggregates and / or fraction of sticks to be produced.

The different operating steps carried out dry on the mixture 9 of rubble according to the invention and carrying out the proposed process can be easily seen from the above structural and functional description of the separator device and its operation. A redescription of the same will therefore be omitted, for which reference is made to the following claims.

In practice, although optimal results have been obtained with the sizing referred to above by treating a mixture of rubble with a grain size of 30/70 mm, it is implicit that said dimensions may be adapted from time to time not only according to the different compositions of the mixtures. of rubble to be treated, but also as a function of the various operating parameters to be set, such as the speed and feed rate of the rubble, the inclination of the vibrating surface, the degree of humidity of the treated mixtures, the presence of components in them more or less adhesive and so on, without thereby departing from the scope of protection defined by the following claims.

In practice, it will also be possible to replace single parts with others that are technically and / or functionally equivalent, such as for example providing a fan-like arrangement of the dividing walls, tapering towards the composite opening with variable span 13, or conferring on the end portion of the supply belt 11 an oscillating movement like a flag, to thus facilitate the thin-layer distribution of the mixture 9 on the initial part 12 of the separator 1, and so on, without thereby departing likewise from the scope of protection of the invention.

Claims (15)

R i v e n d i c a z i o n i 1. Process for the dry separation of the light and heavy fractions of granulometrically preselected rubble mixes, using a vibrating screen or similar type of advancement plan, characterized in that it comprises the following steps: a) a single-layer leveling phase of the rubble mixture fed into the initial part of the vibrating plane, b) a preliminary orientation phase in the longitudinal direction of the longest sticks by creeping impact on dividing walls defining guide corridors or with components of the heavy fractions dragged concomitantly on the vibrating plane, c) a phase of advancement of the mixture of rubble with guiding / maintaining the substantially longitudinal orientation of the sticks in said guiding corridors, d) a phase of falling by gravity and the formation of a first curtain, formed by the smallest pieces of the light fractions crossing the free opening of a composite opening with variable span, as well as by the parts of the heavy fractions crossing both said free opening and the 'entire composite aperture with variable light, the latter actually from the largest and heaviest parts of the particle size considered, e) a cantilevered and mobile "bridge" step over the free opening of said composite opening with variable span, by the light parts and longer sticks, which subsequently fall by gravity from the free end of the vibrating plane forming a second curtain consisting of only light fractions, where f) an optional pneumatic phase is also provided for removing the lighter fractions of the longer sticks which can be carried out on the rubble curtain upstream of the vibrating plane. 2. Process according to claim 1, characterized in that the preliminary orientation step of the sticks in the longitudinal direction is assisted by an action of lifting, rotating and falling onto the vibrating plane carried out by means of a wedge-shaped opening edge provided on each wall dividing. 3. Process according to claims 1 and 2, characterized in that the elasticity of the flexible edge defining the variable opening is chosen in such a way as to determine: a) an elastic bending of said edge under the weight of the larger pieces of the heavy fraction due to their gravity fall, e b) a substantially horizontal self-positioning of said flexible edge both when not stressed and when stressed by the longer sticks overcoming the free opening of the composite opening with variable span in the manner of a mobile bridge. 4. Process according to claim 1, characterized in that a pneumatic action is applied to the curtain of the mixture of rubble fed on the vibrating plane and to the first and / or second curtain to remove the pieces of light fractions, lighter than the smaller sticks. long, such as bits of synthetic material, paper, small bits of wood, and so on. 5. Process according to one or more of the preceding claims, characterized in that the said steps of pneumatic removal of the light parts, lighter than the longer sticks, which can be carried out on the curtain of fed rubble, as well as on said first and second curtains, can be performed both individually or in combinations with each other as desired. 6. Separator of the heavy and light fractions of pre-selected granulometrically selected building rubble for carrying out the processes according to claims 1 to 5, comprising a vibrating plane in the form of a vibrating screen or the like for advancing the mixture of rubble, for example of the type supported by oscillating them to adjust the inclination of said vibrating plane, as well as associated vibration means, characterized in that: a) the area (12) of the vibrating plane (3) for receiving the mixture (9) of rubble has a width which is greater than the width of the conveyor belt or the like (11) for feeding said mixture (9) so as to achieve a thin-layer or monolayer smoothing of the mixture (9) fed, b) downstream of said zone (12) for receiving the mixture (9), on the vibrating plane (3) there is a plurality of partition walls (7) arranged longitudinally and spaced apart, defining orientation corridors (8) / longitudinal guide of the longest wooden sticks (27) present in the rubble, c) that in correspondence with the final portion of said partition walls (7) there is a composite transversal discharge opening (13) with variable span, defined by a free opening (14), the downstream edge of which is formed by a flexible edge (16) of elastic material, in a single piece or in the form of adjacent tabs (32), elastically yielding under the weight of the pieces (22) larger than the heavy fractions passing through said composite opening with variable span (13) but substantially self-supporting under its own weight and the weight of the longer wooden sticks (27), or other pieces (26) larger than the light fractions, d) that downstream of said composite opening with variable span (13), through whose free opening (14) the first curtain (21) of mixed fractions falls, the vibrating plane (3) ends with a falling edge (19) sticks (27) and pieces (26) of light fractions with a length greater than the width of the free opening (14) of the variable opening (13), if not previously eliminated, such as sticks (27) and any pieces (26) of light fractions, lighter than the longer sticks (27), form a second curtain (24) made up of only materials of the light fractions, and e) that at least one of said first and second curtains (21 and 24) and curtain (9A) of the mixture fed on the vibrating plane (3), preferably to all said curtains (10, 21 and 24), a pneumatic means is associated (29, 10) adapted to carry out a pneumatic removal of the light parts (23 and 26), which are lighter than the longer sticks (27), said pneumatic means (10, 29) being individually controllable. 7. Separator according to claim 6, characterized in that the partition walls (7) are provided or arranged so as to form orientation / guide corridors (8) having an increasing width in the longitudinal direction, or fan-shaped, where the front side of impact (28) is performed as a bevelled lead-in side in the vertical plane, acting as a side for lifting, rotating and dropping the sticks (27) onto the vibrating plane (3). 8. Separator according to claim 1, characterized by the fact that the length of the strip or flexible edge (16) is preferably between 50% and 100% of the length of the free opening (14). 9. Separator according to claim 6, characterized in that said flexible edge (16) is supported, preferably replaceable, on the vibrating plane (3) in a slightly lower height position than the vibrating plane (3) upstream of the opening composite with variable span (13), so as to safely accommodate even sticks exceeding the free span (14) with ends slightly inclined downwards. 10. Separator according to claim 6, characterized in that said partition walls (7) extend beyond said composite variable opening (13). 11. Separator according to claim 6, characterized in that the end portion (18) of the vibrating plane (3) is inclined downwards. Separator according to claim 6, characterized in that the portion (12) for receiving the fed rubble mixture (9) is preferably provided in steel or another material, for example polyurethane, having a high flow coefficient. 13. Separator according to claim 6, characterized in that it has the following dimensions, with reference to a mixture of rubble having a grain size of 30/70 mm: a: width of the vibrating table 3 = 600 min b: total length of the vibrating table 3 = 1.180 mm c: length of the monolayer leveling portion 9 of the feed mixture 9 = 400 mm d: length of the partition walls 7 = 780 mm e: length of the inclined end portion 18 of the vibrating plane 3 = 134 mm f: total length 13A of the composite opening with variable span 13 = 100 mm g: length 14A of the free opening 14 = 60 mm h: length 16A of the elastic edge 16 = 40 mm i: height of the partition walls 7 = 100 mm j: initial width of the orientation channels 8 = 120 mm j ': final width of the orientation channels 8 = 150 mm k: vibrating unit suitable for generating substantially coplanar back and forth vibrations, 1: difference in height S between the vibrating surface 3 and the underlying flexible edge 16 = 8 mm. 14. Separator according to claim 6, characterized in that the vibrating plane (3) carries out substantially coplanar back and forth vibrations. 15. Plant for the separation of light and heavy fractions of mixtures of building rubble, characterized by the fact of comprising a separator (1) for the removal of light fractions, and in particular of wood sticks (27) of prevalent longitudinal extension, from a mixture of rubble (9) previously pre-selected granulometrically, according to one or more of claims 6 to 14.