EP0501565A1 - Process for pressing, dehumidification and conditioning of soaked hides and continuously operating machine for execution of this process - Google Patents

Abstract

According to the process, the soaked hides to be dried are moved between two endless belts made of felt (8, 9) and felt (2) in the pressing operation and of felt (31) and of steel (18) in the dehumidification operation, with optional interposition of a transfer cloth (12) and with compression drums (4, 5, 6, 7, 21, 29); radiant elements (28) are arranged between two adjacent drums (21, 29) in the dehumidification region, the speed of travel of the belts being adjusted as a function of the temperature of the abovementioned radiant elements (28), of the thickness of the hides to be treated and of the desired final degree of humidity. The patent also refers to the machine which is suitable for implementing this process, which machine is described in the patent according to a number of alternative optional forms of embodiment. <IMAGE>

Description

The subject of the present invention is a process by which soggy skins which come out of barrels or of continuously operating machines suitable for tanning or dyeing, are dehumidified until the humidity is brought to an acceptable level suitable for allowing their passage subsequent to subsequent treatments.

It is known that on leaving barrels or machines with continuous operation for tanning or dyeing, the skins are in a completely soggy state with a relative humidity of the order of 100%.

To be able to be subjected to subsequent treatments, tanned hides must be brought, using pressing operations, to a relative humidity of around 40 to 50% by weight, while dyed hides, to be susceptible to undergo subsequent treatments, must be brought to a homogeneous relative humidity, of the order of 15 to 20%, and this by means of pressing, dehumidification and conditioning operations.

In the current state of the art, the pressing operation of the skins is obtained by passing them continuously between conveyor belts of felt, of a type known per se.

Currently, the dehumidification operation is carried out in different ways. By way of example, one of the most commonly used processes consists in gripping the skins after pressing them, in spreading them manually using appropriate spatulas on heated panels, possibly under vacuum, until bringing said skins skins at a moisture level relative to the order of 25 to 30%, and to hang them on an aerial chain or inside hot air ovens, until obtaining the final relative humidity which allows, as far as one has realized homogeneity over the entire surface of the skin, moving on to subsequent treatments. If it turns out that the relative humidity is not homogeneous, the skins should be rehumidified using appropriate tanks provided with water jets, these skins being thus left in a stacked state, until '' to obtain sufficient homogeneity.

It is easy to see that the numerous passages and displacements that the skin must currently undergo during this series of operations, involves a considerable expenditure of time, energy and manpower; workers are forced to work in a humid atmosphere in the presence of unhealthy vapors, generated by the heating plates or under vacuum, the heat given off by these coming into direct contact with operators.

The method according to the invention replaces this current series of operations with a single operation which makes it possible to drastically reduce the space occupied, the time, the manpower and the energy used, being further noted. that operators no longer come in contact with moisture, steam or heat.

The invention also relates to the machine for implementing the above-mentioned method, which machine will be described below according to various possible embodiments, all of which fall within the field of patent.

In all these embodiments, the drying machine comprises a first cold pressing operation with felt carpets and then with a canvas or equivalent carpet, which advances at a determined speed, at the same time as a flexible flexible steel carpet or an equivalent steel drum, itself heated and moving at the same speed as the carpet in you in order to transfer the skins which are introduced between the two carpets or between the carpet and the drum in order to bring them at the end of the drying operation until the subsequent treatment, the absorption of humidity being ensured by means of a series of felts or using a unique felt rug.

It is understood that the series of felt mats or the equivalent equivalent felt ensures the compression among the rollers of the skins which advance between the two parallel mats or between the transfer mat and the cylinder, which promotes the transfer of the vapor and operates the progressive dehumidification of the skin.

According to another characteristic of the invention, there are associated with the series of felt carpets or with the single felt in the dehumidification zone, radiant elements which eliminate the moisture released during the drying operation between the felt carpets. or the single carpet, this elimination occurring before the carpets or the carpet come back into contact with the skins to be dried.

The machine will now be described in more detail in each of its particular structural embodiments; these embodiments having been described below by way of nonlimiting example.

In the drawings:

• fig. 1 (plate I) is a side view showing a first embodiment of the machine according to the invention, with a first part constituted by pressure rollers which replace the usual press of known type.
• FIG 2 (plate II) is a schematic plan view of the assembly according to FIG. 1.
• Fig. 3 (plate III) is an elevation view.
• Fig. 4 (section IV) illustrates a side view of a second embodiment of the machine according to the invention.
• Fig. 5 (panel V) is a side view of another variant in which the soggy skins to be dried move in a circular path.
• Fig. 6 (plate VI) is a schematic plan view of this third constructive embodiment of the machine according to the invention.

Special description of the machine

In the first embodiment of the machine as illustrated in FIG. 1 to 3, there is provided an endless conveyor belt 1 preferably made of a synthetic material and set in motion by a motor 2 (fig. 2), by means of which the skin which is spread manually by the direction of the arrow 3 is pr the enlarged sequence automatically introduced between the pressing rollers 4, 5 and 6, 7 which constitute a device similar to that normally called a press.

Advantageously, on the lower drums 5 and 7 can be rolled up cloth carpets of the multi-spiral type referenced 8 and 9 or among equivalent carpets, which are stretched and undergo a deflection on the drums 10 and 11.

During its advance, the skin is supported on a canvas mat 12 which, as a result of its particular embodiment in the form of a net capable of bringing no damage or trace to the skin, even if it is pressed, present the characteristic of allowing the liquid medium, vapor or air to pass easily according to the different phases in which it is involved.

This mat is driven by the drum 13 itself rotated by the motor 14 (Fig. 2), so as to then pass over a drum 15 mounted mad which also acts as a guide and finally to reach the return drum 16 by passing over the carpet 8 which moves on the drum 5, so as to take the skin which comes from the carpet 1 until bringing it to the exit of the machine. This skin therefore passes over the drum 17 above the steel belt 18 to the return drum 19 to return to the drive roller 13 at which the skin exits in the direction indicated by the arrow 20.

The pressing operation, provided adjustable, is carried out using a series of opposite drums.

The upper drums 4 may be covered with rubber in order to prevent any wrinkling or possible deformation of the skin, and they are rotated by the synthetic mat 22 which derives its movement from the drum 23 itself rotated by motor 24 (fig. 2).

The idle lower rollers 5, combined with the return drums 10, support the multi-spiral canvas carpets or felt carpets 8 and 9.

Due to its particular spiral conformation, this carpet in you or felt carpet lets pass instantly the liquid from the skin under the pressing effect and it is represented continuously in the optimal state to receive the next skin .

During this first pressing phase, we can obtain a maximum extraction of the liquid from the skin, with minimal pressure exerted on the drums 5-7 because of their conformation, the carpet in you the 12th and the carpets spiral or felt 8 and 9 are particularly suitable for promoting the passage of liquid from the skin and its immediate elimination by gravity, so that the liquid will move towards the flow 26.

Still supported and transported by the canvas mat 12, the skin will continue to move towards the dehumidification phase where there is a steel mat 18 mounted on drums 17 and 25, one of which receives its movement motor 27.

This carpet is heated using special heat sources, for example by infrared rays 28. The drums 17 and 25 and a series of drums 21 exert a back pressure on a series of rubberized drums 29 which, in association with the return drums 30, drive the felt carpets 31.

At this time, the skin, forced to pass between the steel mat 18 and the mat in you on the 12th being compressed between the different pressure and backpressure drums, will be subjected by the effect of heat to the thermal jump necessary to transform moisture into vapor present in said skin; which humidity, thus compressed, will increase considerably in volume and will be forced to migrate outside the skin, passing through the fabric 12 stretched upwards to be finally absorbed by the felts 31.

During each pressing operation, a relative portion of humidity is thus obtained in the form of vapor, which is absorbed by the corresponding felts; the latter are continuously repackaged, by emission of hot water from a series of radiant elements 32 (FIG. 3), this hot water being distributed over the felts by a series of conduits 33, so that said felts are always able to present themselves under optimal conditions for absorption.

Then, the skin, still held between the canvas carpet 12 and the steel carpet 18, these two being supported by the drum 17, passes into the upper part of the machine for the conditioning phase.

In the path between the drum 17 and the drum 25, the skin is held in adhesion by idle support rollers 34 and by opposite counter rollers 36 with rubber lining, the latter also providing support for the mat 12 and the skin in the return journey.

It will be observed that this double path can be repeated more than once.

A series of drums 35, formed by overlapping disks, ensures the inversion of the skin on itself until it penetrates between the cloth carpet 12 in the return phase and the carpet in the form of a net or thread 37 which advances madly, the latter having the function of accompanying the skin until it leaves its machine. During this double path, the skin is conditioned by the introduction of hot and dry air from the closed circuit installation 38 (fig. 3), which is equipped with a heat pump and a condenser of the type usual.

Along this path, the air is suitably distributed using a series of ducts 39.

In its part intended for dehumidification and conditioning, the machine is protected by athermic panels 40, in order to minimize the dispersion of the heat used.

According to a first variant of the machine according to the invention as illustrated in FIG. 4, instead of the series of felts 31 illustrated in FIG. 1, use is made of a single felt mat 41, which, starting from the drum 42, arrives at the drum 43 which is driven via a chain transmission by the drum 44 which, starting from the drum 42 arrives at the drum 43, which is driven through a chain transmission, by the drum 44 so as to then pass over the drum 45 and reach the drum 46, these two drums acting as a reference and one of these also serving as a guide for the felt, thus returning to the drum 42.

The conditioning of the felt is obtained by introduction of hot air coming from radiant elements and being distributed on the felt by a series of guide panels 47. The cloth carpet 48, which starts from the drum 49, arrives at the driving drum 44 and then pass through the drum 50 to the drum 51, these last two drums acting as a reference and one of them also ensuring the guiding of the belts with a view to their return to the drum 49, or else can return after having deposited the skin on drum 42.

The skin will come out at the level of the drum 44 and in the event of adhesion to the steel mat 52, provision is made for the intervention of a detachment device 53 of a type known per se. The remaining part of the machine can be produced as in the previous example which has been illustrated in FIG. 1, 2 and 3.

The pressing and dehumidification operation can therefore be supplemented by that of packaging, by making the upper part of the steel mat as illustrated in FIG. 1 to 4.

In the variant of the machine which has been illustrated in FIG. 5 and 6, it is provided to replace the steel belt 18 mounted on the drums 17 and 25 and heated by heat sources with infrared rays 28 as illustrated in FIG. 1, a steel cylinder 64 internally heated, for example by means of a hot liquid contained in the intermediate chamber 55, this cylinder 64 possibly being set in motion by the motor 56 (fig. 6).

As shown in fig. 5 the cloth carpet 57 which arrives from the drum 58 passing over the drum 59 is wound up on the roller 54 to then pass over the idler rollers 60 and 61, one of these acting as a guide for the carpet, by completing in this way the path of the latter which is represented on the drum 58.

The belt 57 is driven by the cylinder 58 and by counter rollers opposite pressure 62 and 63.

Around the cylinder 64 a felt mat 65, passing over the drum 66, is wound on the cylinder 64, while the motorized pressure drums 67 advance the pea, providing on the same the necessary pressure. The felt carpet 65 is conditioned continuously by means of the admission of hot air coming from radiant elements 70, as also visible in FIG. 6.

The mat 72, set in motion by the motor 73, will take the skin which comes out in the direction indicated by the arrow 74 in order to bring it to subsequent treatments. The process can therefore be considered similar to that which has been previously described.

In the foregoing description, in each case only the pressing and dehumidification operations have been indicated. The process can be completed by the skin conditioning operation, by providing an additional tunnel in the manner which has already been described in the embodiment illustrated in FIG. 1.

Advantages of the invention

• 1 - Il n'est plus nécessaire d'effectuer des opérations manuelles sur des panneaux chauds ou mis sous vide, ce opérations étant très dangereuses et insalubres pour les ouvriers ainsi que pour l'ambiance elle-même du fait que la vapeur reste à l'état libre dans l'air.
• 2 - L'énergie employée avec le procédé suivant l'invention est réduite d'environ 30 à 40% par rapport aux méthodes en usage à l'heure actuelle.
• 3 - La réduction du déplacement des peaux comporte des avantages évidents quant a l'espace occupé et quant à la main d'oeuvre employée; cette main d'oeuvre peut être réduite jusqu'à 70% par rapport au procédé actuellement en usage.
• 4 - Le présent procédé est encore avantageux en ce qui concerne la qualité finale des peaux, et ce aussi bien en ce qui concerne les caractéristiques techniques (la fleur reste plus compacte avec la chair, de sorte que la peau est beaucoup moins soufflée) que l'expansion de la peau (mesurée en pieds²) du fait qu'au cours de tout le processus, la peau reste contrainte et étendue, si bien qu'elle n'est pas soumise à des retraits dûs au séchage comme cela se passe lorsque la peau reste libre.

Among the advantages presented by the process according to the invention and the machine for implementing it, the following may be mentioned:

• 1 - It is no longer necessary to carry out manual operations on hot or vacuum panels, this operation being very dangerous and unhealthy for the workers as well as for the atmosphere itself because the steam remains at free state in the air.
• 2 - The energy used with the process according to the invention is reduced by approximately 30 to 40% compared to the methods in use at present.
• 3 - Reducing the movement of skins has obvious advantages in terms of space occupied and the workforce employed; this labor can be reduced by up to 70% compared to the process currently in use.
• 4 - The present process is still advantageous as regards the final quality of the skins, and this as well as regards the technical characteristics (the flower remains more compact with the flesh, so that the skin is much less blown) than the expansion of the skin (measured in feet²) due to the fact that during the whole process, the skin remains constrained and extended, so that it is not subjected to shrinkage due to drying as happens when the skin remains free.

Claims (8)

Method for pressing, dehumidifying and conditioning soggy skins, with a view to reducing humidity to an acceptable level for their passage to subsequent operations, characterized in that in a single operating machine, the soggy skins transported by a canvas mat which accompanies them throughout their journey, are brought to pass through a first pressing device comprising one or more series of opposing drums under pressure, to then pass to a dehumidification phase at the level of which a carpet or a cylinder is provided. in suitably heated steel which acts in opposition with a series of rotating felts or with a single rotating felt, to finally arrive at the conditioning phase comprising the introduction of hot and dry air into the atmosphere in which the skin moves. Machine for carrying out the method according to claim 1, characterized in that it comprises a canvas conveyor belt (12) which operates in combination with multi-spiral belts (8), this canvas carpet (12) serving for the transport and protection of the skin due to the fact that it leaves no trace on it even under pressure, while at the same time it easily allows the liquid which leaves said skin to emigrate, the multi-spiral mats acting first as a reservoir, until pressing against the pressure rollers (5), then in the manner of catalysts as soon as they assume another position, losing instantaneously all the liquid to return to the free state and suitable for support the carpet in you again on (12). Machine for implementing the process according to the claim 1 and according to claim 2, characterized in that the canvas carpet (12) is supported on multi-spiral carpets (8 e 9) thereby allowing the liquid from the skin to migrate as much as possible around the pressing phase thus ensuring dehumidification while letting the steam pass over the subsequent series of drums (29) with felts (31) thereby allowing subsequent conditioning, while the carpet (12) allows maximum air perspiration towards the skin . Machine for carrying out the method according to claim 1 and according to claims 1 and 3, characterized in that a steel mat (18), which is heated and on which acts a series of back pressure drums (21 ) provided at the level of the pressure rollers (29) placed below and provided with rotating felts (31), creates on each pass a combined effect of heat and pressure capable of causing the skin to expel the residual moisture under form of vapor, which is absorbed by lower felts (31). Machine for implementing the method according to claim 1 and according to claims 2 to 4, characterized in that an installation is provided for the reconditioning of the felts (31) with a view to permanently guaranteeing their power maximum absorption. Machine for carrying out the method according to claim 1 and according to claims 2 to 5, characterized in that an installation for conditioning the skins acts in combination with the installation for reconditioning the felts in this by only adding a heat pump and the corresponding condenser in view dehumidify the air in circulation and introduce this air in the dry state for the conditioning phase with obvious advantages in terms of energy saving. Machine for carrying out the method according to claim 1, characterized in that it comprises a single felt mat (41) which is mounted on a series of drums (42 and 43) and which is driven through a transmission to chain by the drum (44) in order to then pass over the drum (45) and over the drum (46) both acting as a return, one of said drums also acting as a felt guide, then returning to the drum (42), with anticipation of the conditioning of the felt by introduction of hot water distributed on this felt by a series of guide panels (47), while a cloth carpet (48) starting from the drum (49) joins finally the motor drum (44) to pass from the drum (50) to the drum (51), which both act as a return to return to the drum (49). Machine operating continuously for implementing the method according to claim 1, characterized in that it comprises a cylinder (64) provided for example with a heating device, while the felt mat (65) comes to be disposed in contact with the surface of the cylinder (64), in order to produce a similar effect with an obvious advantage of gaining space, while keeping intact all the other characteristics of dehumidification.

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