ES2626449T3 - Improved vacuum dryer for industrial skins - Google Patents

Abstract

A vacuum dryer (1) for drying industrial hides (P), comprising: - a body that includes a support structure (2) with at least one pair of end posts (4, 5) having substantially vertical guide means (11), a lower base (6) and an upper cover (7); - A plurality of substantially horizontal and reciprocally superimposed boards (12) designed to support the hides (P) during their drying, and to be peripherally and hermetically coupled to each other and to said cover (7) to define corresponding vacuum chambers ( 15) to suck the vapors emitted from the skins (P); - means for vertically moving said boards (12) along said guide means (11) fed by a feeding unit (16); - heating means associated with said boards (12) to heat the skins (P) and connected to a heating unit (17); - vacuum means (26) designed to selectively connect to said tables (12) to suck from said chambers (15) the vapors emitted from the hides (P); - control means (29) to control said movement means, said heating means and said vacuum means (26) - a suction line to connect said vacuum chambers (15) to said vacuum means (26), whose line has at least one vapor collector (30) connected to said vacuum chambers (15) of said boards (12) by means of connection tubes (31); characterized in that said vacuum means (26), said supply unit (16), said heating unit (17) and said control means (29) are mounted on said support structure (2) within the projection in the floor of the machine body and not in a separate assembly, at least one steam collector (30) being said directly to at least one of said posts (4) near said boards (12) thereby minimizing the length of said connection tubes (31), the length of said circuit, the volume of steam to be sucked in and the evacuation time of said vacuum chambers (15).

Description

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DESCRIPTION

Improved ford dryer for industrial skins Field of the invention

The present invention generally finds application in the field of the tannery, and specifically refers to a ford dryer for drying wet industrial skins, as defined in the preamble of claim 1.

Background of the technique

Ford dryers are known for industrial skins, which generally comprise a body consisting of a support frame or structure that supports one or more mutually overlapping and substantially horizontal boards, on which the skins are placed during drying.

The support structure is usually composed of at least two vertical columns at the ends of the boards, which have vertical grilles and are mutually joined by a lower base and an upper cover.

Each board can be actuated vertically by appropriate hydraulic actuators or the like, to be moved towards the overlying board and form a suction chamber sealed with it, in which the skins to be dried are enclosed.

In order to facilitate the evaporation of moisture from the skins, the boards are heated by appropriate heating means.

Also, the suction chambers formed by the boards are connected to sources of ford, which comprise one or more ford pumps, which are used to quickly extract the vapors through a circuit comprising at least one collector connected to the boards through appropriate connection pipes.

Generally, the manifold, ford pumps, hydraulic and pneumatic stations and the switchboard form a different assembly, separate from the body and connected to it by a series of flexible or nipple pipes or electric lines.

Thus, as a whole the machine covers an area on the floor larger than the body, thus adding complexity to the distribution of the plant.

Also, in this provision of the prior art, as described for example in documents EP384196 and GB2152530 by the applicant thereof, the flexible tubes connecting the boards to the collector and the latter to the pumps will minimize mutual friction to extend their average life, so they are poorly curved and have a considerable length, which will increase the volume of the internal circuit to be emptied, as well as pressure losses throughout the circuit.

An additional drawback of this type of plant is the presence of one or more external condensers downstream of the boards, which are generally mounted in the ford pump unit and are associated with condensate separators, which require cooled water supplied by a cooler. or cooling towers, thus assuming high maintenance costs, and frequent replacements due to oxidation and contacts with very aggressive vapors and condensates.

Likewise, the presence of these components along the circuit, with inevitable safety valves and shunts, increases pressure losses and supposes a higher energy consumption by the pumps, while requiring longer times for public evacuation. of the boards and therefore longer times to dry the skins that are placed on them, which can be of the order of one minute.

Another drawback of traditional prior art dryers is that, once the plant has been manufactured, it must be disassembled in partial assemblies for shipping and installation in the tannery or workplace, to separate the body with the assembly tables which comprises the steam collector, one or more condensers and condensate separators, the pump unit and the various connection pipes, as well as the flexible pipes for connecting the boards to the steam collector.

Therefore, after such partial disassembly, the body with the boards must be packaged in a box, while the assembly comprising the pumps, the hydraulic and hydraulic stations and the flexible tubes must be placed in a separate container. When transporting to the installation site, the frame must be reassembled with its columns and all the parts of the pump unit must be connected through the flexible tubes, which is a time-consuming process, requiring adjustments and regulations .

Document WO87 / 05944 describes a drying dryer for industrial skins that has all the features mentioned in the preamble of claim 1. However, this previous dryer also has hydraulic lines and steam collection lines that are installed in a separate unit of the body of the

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ford dryer thus occupying a larger floor space and having an increased consumption of ene ^ a for longer connection lines with the dryer.

Description of the invention

A general object of the present invention is to eliminate or at least reduce the above drawbacks, by providing a ford dryer for industrial skins that is very efficient and relatively cost effective.

A particular object is to provide a dryer for industrial skins that is very compact and takes up less space than the conventional apparatus.

A further particular object of the invention is to provide a dryer that has lower pressure losses along the connection circuit, thereby increasing the useful rate and efficiency of the ford means, as well as reducing consumption and downtimes. evacuation of the circuit and drying of the skins.

Another object is to reduce the number of parts to be disassembled for the shipment, thereby reducing the times for both disassembly at the factory and for assembly at the site, and achieving savings in the operation of the machine.

These and other objects, as best explained hereafter, are fulfilled by a ford dryer to dry industrial skins as defined in claim 1, which comprises a support structure having at least a pair of end posts with means of grinds substantially vertical, a lower base and an upper cover, a plurality of mutually overlapping and substantially horizontal boards to support the skins during drying, said boards being adapted to peripherally and hermetically engage to define respective ford chambers to absorb the vapors of the skins, actuating means for moving said boards vertically along said grinding means, which are connected to a feeding unit, heating means associated with the tables for heating the skins, connected to a hydraulic station, adapted ford means for the selective connection to said tables to extract the vapors released from the skins of said ford cameras, control means for electrically controlling said actuating means, said heating means and said ford means, a suction line for connecting said ford cameras with said ford means, comprising at least one steam collector connected to said ford chambers of all tables through connecting pipes. The dryer is characterized in that said ford means, said feeding unit, said hydraulic station and said electric control means are integrated in said support structure and are located within the projection on the floor of the machine body and not in a separate assembly, said at least one steam collector being directly attached to at least one of said posts near said boards, thereby minimizing the length of said connecting tubes, the length of said circuit, the volume of steam that is you must extract and the time for the evacuation of said ford cameras.

This arrangement results in a very compact and condensed dryer structure, which will reduce the overall plant dimensions of the dryer.

Also, the shorter length of the circuit and the lower volume of steam that must be extracted reduces pressure losses, increases the suction capacity and reliability of the plant, reduces energy consumption and evacuation times of suction chambers .

Finally, the structure simplifies the disassembly at the factory, the shipping and reassembly at the installation site and allows saving in terms of costs and installation times.

Advantageous embodiments of the invention are defined according to the dependent claims.

Brief description of the drawings

The features and additional advantages of the invention will be more apparent from the detailed description of a non-exclusive preferred embodiment of a ford dryer for industrial skins according to the invention, which is described as a non-limiting example with the help of the attached drawings, in those who:

FIG. 1 is a general perspective view of a dryer of the invention in a fully assembled state and with a protector;

FIG. 2 is a general perspective view of the dryer of FIG. 1 without the protector;

FIG. 3 is an exploded general perspective view of the dryer of FIG. one;

FIG. 4 is a side view of the dryer of FIG. one;

FIG. 5 is a front view of the dryer of FIG. 1 from a longitudinal end;

FIG. 6 is a front view of the dryer of FIG. 1 from the longitudinal end opposite that of FIG. 5;

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FIG. 7 is a top view of the dryer of FIG. one;

FIG. 8 is the view of FIG. 5 with certain parts partially removed for reasons of clarity;

FIG. 9 is the view of FIG. 5 with other parts partially removed for reasons of clarity;

FIG. 10 is a perspective view of a detail of FIG. one;

FIG. 11 is a perspective view of a detail of FIG. 10;

FIG. 12 is an enlarged perspective view of the dryer pump unit as shown in FIG. one;

FIG. 13 is a schematic view of a pump as shown in FIG. 12;

FIG. 14 is a diagram of the dryer circuit of the invention;

FIG. 15 is a side view of a body prepared to be packaged in a box.

Detailed description of a preferred embodiment

With reference to the previous figures, a dryer of the invention, generally designated by the number 1, is particularly designed to dry flat products such as industrial skins P that have undergone tanning treatments and retain a high moisture content.

The dryer 1 comprises a body consisting of a support structure 2 that defines a longitudinal axis L and is completely covered by a removable protector 3.

In the embodiment of the figures, the protector 3 has two blinds 3 'at its longitudinal ends, which can be raised for easy access to the interior of the machine without disassembling the protector.

The support structure 2 is essentially composed of a pair of longitudinally offset end posts 4, 5, a base 6 interposed between the posts 4, 5 and a flat cover 7.

Preferably, posts 4, 5, base 6 and cover 7 are neatly connected to each other, as best shown in FIG. 4, in such a way that a niche and monolithic support structure 2 is obtained, to form the body. Preferably, the base 6 has 6 'feet for floor mounting.

Preferably, each post 4, 5 is composed of a pair of columns 8, 9 with a polygonal section or the like, which are arranged symmetrically with respect to a vertical plane V that passes through the longitudinal axis L and are mutually connected with slides or ribs located at various heights.

The cover 7 can be anchored to the posts 4, 5 and is integrated in a lattice frame 7 'composed of a pair of longitudinal stringers 10, 10' arranged symmetrically with respect to the vertical plane V and joined by crossbars, also attached to the posts 4, 5.

Columns 8, 9 have vertical grinding means fixed thereto, consisting, for example, of high strength steel grains 11.

The support structure 2 supports one or more substantially horizontal and mutually overlapping identical tables 12 above the base 6.

Slides, not shown, are mounted on the transverse end edges of the boards 12, and slide along the grids 11 to vertically move the boards 12 parallel to themselves, and move them one by one at the working height H from the ground, so that the operators extend the skins P to dry on their upper surfaces 13.

The lower surfaces of the boards 12 and the cover 7 have peripheral seals 14 that are adapted to cooperate with the upper surfaces 13 of the underlying boards to form respective vacuum chambers 15, which can be opened and sealed dramatically. The negative pressure created in the vacuum chambers 15 is useful for extracting the vapors released from the P skins but also provides the benefit of decreasing the pressure and therefore the evaporation temperature of the water in the P skins, thereby reducing the tension thermal in them.

Drive means are provided, which preferably consist of hydraulic cylinders, not shown, for the controlled movement up and down of the tables 12. As shown by itself, the actuators are fed by a feed unit 16 comprising a pump and a control unit operated by valve.

Heating means are also provided to heat the tables 12 and accelerate the evaporation of moisture in the skins P. Particularly, the heating means may consist essentially of

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coils or labyrinths formed on the boards, not shown, and fed with a fluid, preferably hot water supplied by a circuit connected to a hydraulic station 17.

The hydraulic heating circuit, shown more clearly in FIG. 6, comprises a heat exchanger 17 'with a primary circuit that receives water vapor or other high temperature fluid from a tube 18 and a secondary circuit that receives water from a tube 19, pumped by a pump 20.

The hot water flowing out of the exchanger 17 'is transported to a supply manifold 21 and then to the tables 12 through flexible inlet tubes 22, flows through the coils and then out of the tables 12 through of flexible outlet tubes 23 and transported to a discharge manifold 24 from which it flows back to the exchanger 17 'through a return tube 25. Alternatively, the heat exchanger 17' can be replaced by a supply line Direct hot water, for water that comes from an external system, not shown.

It will be noted that the heating circuit, including the supply and discharge manifolds 21, 24 are stably mounted on the post 5.

The vapors released from the skins P are extracted by ford cameras 15 by means of ford, generally with reference 26.

In a preferred non-limiting embodiment, the ford means 26 include a pump unit composed of two tandem pumps, that is, a high performance lobule or Roots pump 27 connected in series to a dry spindle pump 28.

The Roots pump 27 can be of the type that has an internal bypass and an integrated inverter, with an automatic elastic compensation of the bypass valve 27 ', which allows the opening to adapt to the differential pressure Ap between upstream and downstream of the maximum performance pumps, depending on the suction pressure.

The operation of all pumps, valves, hydraulic and pneumatic stations of the machine is controlled by a switch board 29, possibly connected via Wi-Fi to a contact screen that can be integrated into the protector 3 of the body.

The suction chambers 15 of the tables 12 are connected to the pump unit 26 through a suction line.

The suction line comprises at least one steam collector 30 connected to the suction chambers 15 of the tables through respective connecting pipes 31.

Preferably, two steam manifolds 30 are provided for connection to the connection pipes 31.

Conveniently, the tubes 31 are connected to the suction chambers 15 by a pair of side compartments 15 formed near the longitudinal edges of each table 12, as more clearly shown in FIGS. 10 and 11

The side compartments 32 of each table 12 have a series of holes aligned and arranged uniformly 33 in their upper wall, to ensure fluid communication between said compartments 32 and the suction chamber 15 formed between the upper surface 13 and the surface bottom of the overlying table.

Each compartment 32 has a connection 34 at its longitudinal end for connection to a corresponding tube 31. Also, the steam manifold 30 is connected to the pump unit 26 through a suction cannon 35. Thus, the vapors released from the skins P and collected in the ford chambers 15 are extracted through the holes 33 and flow to the side compartments 32, from which they are extracted by the tubes 31 and transported to the steam collector 30; The latter is connected to the pump unit 26 through the suction tube 35.

Advantageously, each compartment 32 houses a condenser 36 with a longitudinal tube bundle 37 for the flow of fine water. Thus, the vapors generated in the ford chambers are extracted through the holes 33 to the compartments 32 where they flow in the tube bundles 37 of the condensers 36, condensing and thereby depositing in the compartments.

Conveniently, in addition to inlet and outlet connections for cooling water, each compartment 32 has respective discharge tubes 38 at the end near connections 34, with free ends equipped with automatic valves 39. Valves 39 are normally closed during the suction operation and open automatically when each ford chamber 15 is opened and the ford is released, so that the skins P are extended on the surface 13.

Conveniently, as clearly shown in FIG. 9, the condensate discharge tubes 38 and their respective automatic valves 38 are slidably housed in two substantially vertical downspouts.

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arranged on the sides of table 12 to prevent re-evaporation of the separated condensate.

A peculiar feature of the invention is that each steam collector 30 is mounted directly on one of the posts of the support structure 2, particularly on the post 4, and near the boards 12, to minimize the length of the connecting pipes 31.

For this purpose, the connection tubes 31 can be flexible low-rigidity tubes formed with wear-resistant materials, to allow curvature with a small radius of curvature and the reduction of the distance between the input and output connections, to limit the length of the suction circuit, the volume of the steam to be extracted and the time required for the evacuation of the suction chambers 15, with a consequent higher suction capacity and greater plant efficiency.

Alternatively, the connection tubes can be nigged or semi-rigid, and have, for example sleeve expansion bellows joints, for selective alignment with the connections or openings formed in the tables in the compartments, not shown.

Also, the vacuum means 26, the steam collectors 30, the suction circuit, the hydraulic and hydraulic stations 16 and 17 are all stably mounted on the support structure 2 within the projection on the floor of the body, to reduce the overall plant dimensions of the dryer.

Particularly, the pumps 27, 28, the hydraulic and hydraulic stations 16, 17, as well as the control switch board 29 are mounted on the lattice frame 7 'above the cover 7, whose upper surface defines a walking surface for any required maintenance of all stations and control means.

Conveniently, the pump unit 27, 28 is connected to the steam manifold 30 through suction pipes 35 integral with the post 4. Each steam manifold 30 is substantially vertical and has a plurality of connections 41 uniformly arranged at along its vertical extension, for connection pipes 31.

Likewise, each suction tube 35 is also substantially vertical and has a cyclonic condensate separator 42 at its bottom and, which is connected to a condensate collection container 43

Finally, the vertical suction tubes 35 are connected to the pump unit 26 by horizontal tubes 44, 45 (see Figure 7).

Due to the vertical arrangement of the suction tubes 35, the vapors naturally tend to rise upwards towards the pump unit, thereby increasing the flow rate in the circuit, while the condensates tend to settle down facilitating that mode the separation of moisture contained in the vapors.

Also, since connections are made using a very small number of valves, connections and throttles, pressure losses along the vacuum circuit have been considerably reduced.

The improved efficiency of the circuit, in combination with a lower volume of evacuation in the circuit, allowed to offer shorter suction times, reduced energy consumption, reduced noise and improved dryer performance.

Thanks to this configuration, the following benefits have been obtained:

- a higher suction capacity, that is approximately 2500 m3 / h compared to the normal 900 m3 / h;

- approximately 20% lower energy consumption of the entire dryer;

- approximately 37% lower energy consumption of the pump unit;

- a table evacuation time reduced by approximately 60%;

- a longer life of wear-resistant hoses, both for vacuum and for hot and cold water;

- removal of the liquid ring pump and working oil;

- a lower noise;

- the simplification of the circuits for the vacuum, the heating liquid and the cooling liquid, which entails a considerable reduction;

- a drying capacity increased by approximately 37%.

In a preferred embodiment, columns 8, 9 are formed by two parts, an upper part 8 ', 9' and a lower part 8 '', 9 '', which are joined by connections 46, the upper part being 8 ', 9 'extrafble and being the bottom

8``, 9 '' integral with base 66.

Thus, the dryer can be prepared for transport by disassembling the upper part 8 ', 9' of the columns, grouping all the boards 12 on the base 6, placing on them the cover 7 and the jealousy frame ^ a monolithic 7 ' , with the pump units and the various stations and control means, while all the circuits and tubes connected are kept and any disassembly and subsequent assembly operations are avoided.

In case of mantimo transport, this assembly will usually be placed in a box, while the top of the columns, the protector and all the accessories can be placed in a separate container. In the case of land transport, the composite assembly of the base, the batch of boards, the deck and the frame with the various auxiliary and control units, stations and circuits will be protected by a plastic packaging in turn covered by the sheet , while the upper part of the columns, the protector and other accessories will be arranged in a special transport vehicle.

The assembly in place will only consist of assembling the columns, restoring the cranes and mounting the external protector, which will offer approximately 35% shorter installation times.

The dryer of the invention is susceptible to a number of changes and variants, within the inventive principle described in the appended claims. All the details thereof may be replaced by other technically equivalent parts, and the materials may vary depending on the different needs, without departing from the scope of the invention.

While the dryer has been described with particular reference to the attached figures, the numbers referred to in the description and the claims are only used for the sake of better intelligibility of the invention and will not be intended to limit the scope. claimed in any way.

Claims (11)

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A ford dryer (1) for drying industrial skins (P), comprising: - a body that includes a support structure (2) with at least one pair of end posts (4, 5) having substantially vertical gma means (11), a lower base (6) and an upper cover (7); - a plurality of redprocally superimposed and substantially horizontal tables (12) designed to support the skins (P) during drying thereof, and to engage peripherally and hermetically with each other and with said cover (7) to define corresponding ford chambers ( 15) to suck the fumes emitted from the skins (P); - means for moving said tables (12) vertically along said gma means (11) fed by a feeding unit (16); - heating means associated with said tables (12) for heating the skins (P) and connected to a heating unit (17); - ford means (26) designed to selectively connect to said tables (12) to suck from said chambers (15) the fumes emitted from the skins (P); - control means (29) for controlling said movement means, said heating means and said ford means (26) - a suction line for connecting said ford cameras (15) to said ford means (26), whose line has at least one steam collector (30) connected to said ford cameras (15) of said tables (12) by means of connection pipes (31); characterized in that said ford means (26), said feed unit (16), said heating unit (17) and said control means (29) are mounted on said support structure (2) within the projection on the floor of the machine body and not in a separate assembly, at least one steam collector (30) being said directly to at least one of said posts (4) near said tables (12) thereby minimizing the length of said connection tubes (31), the length of said circuit, the volume of the steam to be sucked and the evacuation time of said ford chambers (15). 2. Dryer according to claim 1, wherein said ford means (26) are connected to said at least one steam manifold (30) with at least one connecting duct (35) unit with said at least one post (4). 3. Dryer according to claim 1, wherein said suction line comprises, for each table (12) near its longitudinal edges, a pair of side housings (32) provided with a plurality of holes (33) for suction of the vapors of the ford chambers (15) and having a connector (34) for a connection pipe (31) at a longitudinal end thereof. 4. Dryer according to claim 1, wherein said at least one steam collector (30) is substantially vertical and has a plurality of joints (41) for said connecting tubes (31), distributed uniformly along its vertical extension. 5. Dryer according to claim 2, wherein said at least one suction duct (35) has a substantially vertical portion attached to said at least one steam collector (30) and a condensate separator (42). 6. Dryer according to claim 1, wherein a pair of steam collectors (30) are arranged in substantially symmetrical positions with respect to a medium vertical plane (V) passing through said longitudinal axis (L) to transport the vapors collected in said longitudinal side housings (32) of said tables (12), said pair of steam collectors (30) being in turn connected to a pair of supply ducts (35) similarly mounted on the same post (4) ) in a substantially symmetrical relationship with respect to said middle vertical plane (V). 7. Dryer according to claim 3, wherein each of said side housings (32) has in a longitudinal end an outlet hose (38) to evacuate the condensate produced by a respective condenser (36), said outlet hose (38) having an end provided with an automatic valve (39) to drain the condensate collected in said housings ( 32) and transported in a substantially vertical collection channel (40). 8. Dryer according to claim 1, wherein said connecting tubes (31) are flexible and are made of a low wear material suitable to allow a high multidirectional curvature of the tubes to reduce their connection length when each housing is connected (32 ) with a corresponding steam collector (30). 9. Dryer according to claim 1, wherein said heating means comprise a serpentm disposed within each table (12) wherein a heating fluid is supplied through flexible tubes connected to an appropriate heat exchanger (17 '). 10. Dryer according to claim 1, wherein said means of movement of said tables (12) 5 comprise at least a plurality of hydraulic cylinders supplied by said feed unit (16). 11. Dryer according to claim 1, wherein said feed unit (16) and said control means (29) are mounted on the upper surface (7 ') of said cover (7) defining a walking surface for personnel for maintenance and control, said heating unit (17) being mounted on said at least one post (4). 10 12. Dryer according to claim 1, wherein each of said posts (4, 5) is formed by the minus a pair of columns (8, 9), each of which made of two parts (8 ', 8' '; 9', 9 ''), respectively an upper part (8 ', 9') separable from a lower part (8 '', 9 '') and of said cover (7), said lower part (8 '', 9 '') being unitary with said base (6), said upper parts being designed (8 ', 9 ') to be removed while said tables (12) and said cover (7) are designed to be compacted to provide a unitary body for transport, leaving all other connections unchanged to minimize installation time.