WO2024141506A1 - Four de séchage à l'air avec économie d'énergie - Google Patents

Four de séchage à l'air avec économie d'énergie Download PDF

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Publication number
WO2024141506A1
WO2024141506A1 PCT/EP2023/087737 EP2023087737W WO2024141506A1 WO 2024141506 A1 WO2024141506 A1 WO 2024141506A1 EP 2023087737 W EP2023087737 W EP 2023087737W WO 2024141506 A1 WO2024141506 A1 WO 2024141506A1
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WO
WIPO (PCT)
Prior art keywords
drying
fluid
cooling
oven
air
Prior art date
Application number
PCT/EP2023/087737
Other languages
English (en)
Inventor
Luigi Franzoni
Original Assignee
Cefla Societa' Cooperativa
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Cefla Societa' Cooperativa filed Critical Cefla Societa' Cooperativa
Publication of WO2024141506A1 publication Critical patent/WO2024141506A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/02—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity of multiple-track type; of multiple-chamber type; Combinations of furnaces
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B15/00—Machines or apparatus for drying objects with progressive movement; Machines or apparatus with progressive movement for drying batches of material in compact form
    • F26B15/10—Machines or apparatus for drying objects with progressive movement; Machines or apparatus with progressive movement for drying batches of material in compact form with movement in a path composed of one or more straight lines, e.g. compound, the movement being in alternate horizontal and vertical directions
    • F26B15/12—Machines or apparatus for drying objects with progressive movement; Machines or apparatus with progressive movement for drying batches of material in compact form with movement in a path composed of one or more straight lines, e.g. compound, the movement being in alternate horizontal and vertical directions the lines being all horizontal or slightly inclined
    • F26B15/18—Machines or apparatus for drying objects with progressive movement; Machines or apparatus with progressive movement for drying batches of material in compact form with movement in a path composed of one or more straight lines, e.g. compound, the movement being in alternate horizontal and vertical directions the lines being all horizontal or slightly inclined the objects or batches of materials being carried by endless belts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
    • F26B21/02—Circulating air or gases in closed cycles, e.g. wholly within the drying enclosure
    • F26B21/04—Circulating air or gases in closed cycles, e.g. wholly within the drying enclosure partly outside the drying enclosure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
    • F26B21/14—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects using gases or vapours other than air or steam, e.g. inert gases
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B23/00—Heating arrangements
    • F26B23/001—Heating arrangements using waste heat
    • F26B23/002—Heating arrangements using waste heat recovered from dryer exhaust gases
    • F26B23/005—Heating arrangements using waste heat recovered from dryer exhaust gases using a closed cycle heat pump system ; using a heat pipe system
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/06—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity heated without contact between combustion gases and charge; electrically heated
    • F27B9/10—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity heated without contact between combustion gases and charge; electrically heated heated by hot air or gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/30—Details, accessories or equipment specially adapted for furnaces of these types
    • F27B9/3005—Details, accessories or equipment specially adapted for furnaces of these types arrangements for circulating gases
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
    • F27D17/10—Arrangements for using waste heat

Definitions

  • the present invention relates to apparatuses and a method for drying pieces, preferably having the shape of panels or components.
  • the invention relates to an oven comprising at least two distinct chambers arranged in series, a first chamber for drying pieces, and a second chamber for cooling said pieces, for drying painted pieces made of sundry materials (wood and its derivatives, fibre cement, glass, plastics, etc.), wherein a heat pump is advantageously employed, in order to bring the drying fluid and the cooling fluid in the drying chamber and in the cooling chamber, respectively, to the desired temperature, making a more efficient use of the energy at play.
  • the present invention is described in two distinct embodiments, which nonetheless make use of the same inventive concept.
  • the oven is in the form of a tunnel oven, while in the second embodiment the oven is in the form of a vertical multilevel oven.
  • said apparatuses are defined as oven, tunnel, tunnel oven or vertical oven.
  • the drying fluid is mainly air, but also other gases might be used, e.g. inert gases.
  • the measures of such panels range 100x300x2 mm to 1600x3500x300 mm.
  • Such ovens can also dry continuous sheets of materials having their third dimension (thickness) smaller than their other two dimensions, thanks to the feature of these ovens of allowing a continuous passage of pieces (one-level tunnels as described in the following).
  • said pieces can reach lengths of over 6 metres, with a typical width of 1300- 1600 mm and a typical thickness of 5-300 mm.
  • drying components e.g. automotive components, which can be provided with non-planar shapes, but which are dried on supporting frames.
  • the assembly of frame and components supported by said frame reaches dimensions similar to the above-quoted ones. Nonetheless, the process is applicable also to bigger components provided with three similar dimensions, like car bodyworks, car bumpers, windows, which can be provided with dimensions bigger than those described in the preceding paragraph.
  • drying means the step wherein the applied paint passes from its liquid to its solid phase, while in cooling the solidified paint and the piece on which it is applied are brought from the drying temperature to a temperature near to room temperature.
  • drying temperature and speed affect the final result: when the drying temperature is too high and/or the drying speed is too fast, paint cracks or aesthetical defects can form in the paint layer covering a panel. For this reason, in the art it is known to perform a process known as flashing off, wherein the process temperature is low, about 15-35°C.
  • Flashing off has the aim of removing most of the solvent, while paint is still fresh; flashing off is performed at temperatures near to room temperature (15-35°C) in order to prevent the curing of just the surface of the paint while the underlying paint is still soft, which could lead to surface defects of the applied painting layer.
  • the actual temperature of the environment wherein the oven is installed sometimes requires to heat the flash off chamber.
  • drying when drying, higher temperatures are used, typically 40-100°C, in order to complete the drying of solvents and accelerate the polymerization of paint, and therefore paint hardening. From the point of view of process time, drying is the longest step.
  • the temperature of the environment can vary widely according to the geographical location of the plant and to the season of the year.
  • the environmental air used for cooling can be taken from outside the production line or from the environment wherein the plant is installed. This means starting from environmental air having a temperature ranging -20°C to +40°C. Therefore, heating or cooling the air provided to the cooling chamber might be necessary, in order to bring it to the required 10- 30°C. In the known art, sometimes a chiller must be provided in order to obtain the cooling fluid at the desired temperature.
  • the pieces to be dried are arranged on a plurality of superimposed levels, each level provided with its own conveying system; the conveying systems are arranged in a mobile pack moving upwards and downwards in the vertical direction, that takes a position according to a FIFO logic at the working level of the productive line in order to load and unload pieces, so as to increase the drying time with a limited footprint.
  • the pieces to be dried travel in parallel inside a tunnel. In this way, the pieces to be dried follow a linear path, different from the typical meandering or ring path of vertical multilevel ovens, but stay for a longer drying time with respect to one-level tunnels, one-level and multi-level tunnels being provided with the same length.
  • vertical ovens for drying pieces are well known in the art, being e.g. described in the utility model IT221807 of the same applicant, or in EP2609021B1 of Haenel or in GB2078651 of Lienhard.
  • vertical ovens for drying pieces with trays moved by chain lifting systems that can be motorized, i.e. suitable for being moved by or housing suitable motorizing means fixed to the frame of the oven, in order to obtain the automatic loading and unloading of the pieces.
  • vertical ovens with trays comprise a plurality of superimposed trays arranged in a plurality of adjacent stacks contained in chambers, along which the trays are shifted through lifting chains.
  • a tray When a tray reaches the top of an ascending stack (i.e. in which the chain moves trays toward the top), it is shifted on the top of a descending stack (in which the chain moves the trays toward the bottom) through suitable devices for horizontal shifting.
  • the trays are shifted to the base of the first ascending stack to be collected by the relative lifting chain. In this way, each tray of the oven follows a complete meandering or ring path through the oven, during which the panels, arranged on the trays, dry, and often cool down.
  • the shape of vertical ovens having a plurality of superimposed trays, allows a good storing capability with a limited footprint, allowing a dwell time inside the oven itself that can vary from some ten minutes to over a couple of hours, according to production line speed and dimensions of the oven itself.
  • vertical ovens comprise two chambers; nonetheless other embodiments are known, comprising a plurality of chambers, typically a multiple of a pair of chambers, i.e. e.g. from two to six chambers.
  • Such ovens are e.g. described in MI97A000463 Elmag and IT 1309018 CEFLA.
  • the trays typically follow a meandering path, and the loading and unloading of the pieces can occur from the same chamber or from two different chambers, as appropriate.
  • Another well-known embodiment comprises three chambers and two stacks, wherein the central chamber is empty.
  • oven chambers need independent air inlets and outlets. This entails at the exhaust of each chamber, and in particular of the drying chambers, a dispersion of energy under the shape of heat, because hot air is dispersed outside the oven, and the need to warm up the replenishing airflow taken from the environment in order to compensate for the exhaust airflow.
  • the flashing off occurs in the first chamber/s, the drying in the central chamber/s, and the cooling down in the last chamber/s.
  • Ovens for drying panels are well known in the art; normally, such ovens use hot air that is heated through water heat exchangers, steam, electric heaters or other means. All these systems are provided with an efficiency lower than 1 : in the face of 1 kWh consumed, in the best of hypotheses the energy available for heating the air needed for drying paint is about 0.85 kWh. In the case of electric heaters, the efficiency is even lower, in that it is linked to the efficiency of the electric energy production and distribution chain: typically, efficiencies around 40% are reached.
  • the term efficiency is avoided, as by definition it is always lower than 1.
  • the term performance is used, which is expressed as a Coefficient Of Performance (COP), which is the ratio between supplied energy (provided heat) and consumed energy (generally electric energy, required by the compressor), usually indicated in technical physics as coefficient of effectiveness.
  • COP Coefficient Of Performance
  • a value of 3 for the COP means that for each kWh of consumed electric energy the heat pump transfers 3 kWh of thermal energy from or to the interested source.
  • CN107843113A of Guangxi Xuteng Ind. describes a kiln for the production of ceramics.
  • the recirculation of air is provided through a system of fans 3, defined as heat pump in the sense that such fans transfer heat from an area to another area in the oven; nonetheless, they are not provided with the elements characteristic of a heat pump.
  • the high temperatures required for firing ceramics entail the need of a heating system for the kiln.
  • CN214440639U of Jiangsu Yutong Drying Equipment describes an oven for drying paint working in a closed circuit, without exhausting heat outside, which can be recovered through a heat pump. Said oven can recover organic solvents and humidity evaporated from paint. Said oven comprises a heat pump that is used for energy saving, but which does not recover energy from the air exhausted in the environment, as there is no air exhausted in the environment.
  • EP3767215B1 of Wienerberger AG describes a dryer and a kiln for producing ceramics, wherein exhaust gases are recovered, and through an absorption heat pump, having a different cycle from a compressor heat pump, a heating fluid is produced and sent to the dryer.
  • the air exhausted from the oven, through an intermediate heat exchanger heats water that is sent to the evaporator of the heat pump; in the heat pump, through the absorption process, water with a higher temperature is produced in the circuit of the condenser, which is sent to heat exchangers placed in the kiln in order to produce hot air in the kiln.
  • the temperatures at play are quite high: the kiln works at 750- 1200°C, while the dryer works at 80-120°C, which require to use other energy sources in addition to the heat pump, in order to obtain the high temperatures required for firing ceramics.
  • the heat pump is an absorption heat pump which, differently from compressor heat pumps, works without the use of a compressor, exploiting the available high temperatures in order to increase the temperature of the refrigerant fluid and of the absorbing fluid of the heat pump.
  • CN210725526U of Yancheng Tianyue Xiafeng Electronic Tech describes a system for drying circuit boards which does not take and does not exhaust air from/into the environment.
  • the closed system for recirculating air has the aim of condensing the substances evaporated during the baking of circuit boards and heating the recirculated air again.
  • US4173924A of Schwitzer Industrial Corporation describes a paint spray booth for painting cars comprising a heat pump.
  • Said heat pump is used for conditioning the air taken from the environment, heating or cooling air according to the season working of said booth, so as to always have air having constant temperature (62-75°F) and humidity inside said spray booth.
  • Said temperatures are significantly lower than drying temperatures, while the heat pump plays the role of a conditioning group with inversion of the cycle between summer (when it cools) and winter (when it heats).
  • EP3117906A1 of Zachodniopomorski Univ. Tech. W Szczecinie describes a spray booth with heat recovery comprising a heat pump, which further comprises heat exchangers and heating systems.
  • CN109682206A of Fujian Ronghua Science and Tech CO LTD describes a furnace body for polymerizing lithium iron phosphate in the field of battery production.
  • the heating and cooling system comprises an air heat pump.
  • the furnace environment is filled with an inert gas for a process with hot gas wherein there is not recirculation, but replacement of the oxygen in the drying chamber with pre-heated nitrogen through a heat pump, keeping the furnace closed at its ingress and egress. Once the furnace is opened, the gas must be replaced.
  • the furnace works in batch, not in a continuous way. There is no hint of the use of a heat pump also for the cooling, and the heat pump is simply used as a replacement of electric heaters.
  • the use of the supplied energy (100%) can be schematized as follows: a. about 2% for supplying the conveying system for pieces; b. about 8% for supplying the fans providing the circulation of air in the oven (taking air from environment, exhausting air into environment, and recirculation of air inside said oven); c. about 90% for heating the air used for drying/flashing off pieces and where necessary for cooling the air needed for cooling pieces, if required according to the temperature of the environment.
  • the portion c i.e. the energy supplied for heating, is largely predominant with respect to the portions a and b, that in the following will not be considered.
  • the portion c of energy carries out different tasks in the oven: i. Heating paint in order to evaporate solvents and activate the chemical reaction of paint crosslinking; ii. Heating pieces; iii. Heating the inside of the oven, compensating, when fully operational, for heat dispersions both of the walls and of piece inlet and outlet; iv. Heating the air that is reinserted into the oven in order to compensate for the hot air containing solvents that is exhausted outside the oven.
  • the first effect is desired, the second and third effects are not desired, but are inherent and inevitable to the functioning of the oven.
  • the fourth effect is analogous to the sum of the first three effects, when the oven is fully operational.
  • Figure 2 First embodiment, two tunnels placed in series according to the present invention, air/water embodiment, lateral view;
  • FIG. 4 First embodiment, two tunnels placed in series according to the present invention, water/water embodiment, lateral view;
  • FIG. 6 First embodiment, two tunnels placed in series according to the present invention, water/water embodiment, recovering heat also from the drying tunnel, lateral view.
  • Figure 8 Second embodiment, known art vertical oven provided with four chambers and four stacks, axonometric view
  • FIG. 12 Second embodiment, drying chamber and cooling chamber according to the present invention, longitudinal section, water/water embodiment
  • FIG. 14 Second embodiment, drying chamber and cooling chamber with recovery of the drying exhaust according to the present invention, longitudinal section, second water/water embodiment.
  • pieces 2 to be dried are conveyed by at least a known conveying system 3, 3’, preferably in the form of a conveying band or a plurality of rollers. Said pieces 2 are conveyed inside a drying tunnel 6 and successively inside a cooling tunnel 66.
  • the bold black arrows show the conveying direction of the pieces 2 to be dried, while the small black arrows show the flowing direction of drying fluid and of cooling fluid.
  • the heat exchanger 14 transfers heat to the mix of environmental air 11 taken from the environment and recirculation fluid 12, i.e. to the portion of drying fluid intended to be re-inserted in the oven through the air treatment group 30 passing in the heat exchanger 14 of said treatment group 30. Therefore, the heat otherwise dispersed at the exhaust 9’ of the cooling tunnel 66 is advantageously employed to heat the drying fluid of the drying tunnel 6 of the oven 302. Moreover, it allows to cool the mix of airflows 9’ and 12’ before reinserting them in the cooling tunnel. In this configuration, the fan 8’ might be superfluous in that all the airflow could occur through airflow 12’, but is nonetheless shown because it might be useful for obtaining the a Vogellic balance of the cooling tunnel.
  • the heat pump 15 is supplied, in addition to the cooling fluid, with the exhaust portion of the drying fluid 9 of the drying tunnel 6, too, further increasing the recovered energy.
  • FIG. 7 shows a typical oven 61 having four chambers 71, 72, 73, 74 and four stacks 81, 82, 83, 84 according to the known art.
  • a tray 3 When a tray 3 reaches the top of an ascending stack 71 or 73, it is shifted on the top of a descending stack 72 or 74 through suitable devices for horizontal shifting. Through similar devices, at the end of the descending stack 72, 74, the trays 3 are shifted to the base of the ascending stack 73, 71 to be collected by the relative lifting chain. In this way, each tray follows a complete meandering path through the oven, as shown by the arrows, during which the panels, arranged on the trays, dry.
  • Figure 8 shows again an oven 61 according to the known art, comprising the said plurality of trays 3, which following the path shown in Figure 1, perform a drying cycle.
  • the small arrows in Figure 2 show the direction of the drying fluid (typically air).
  • FIG. 9A shows a longitudinal section of the drying chamber 72 of the oven 61 according to the known art.
  • a known air treatment group 30 that, through an inlet, takes air 11 from the environment, while it recirculates air 12 taken from the chamber itself through a recirculating channel 10.
  • Said drying fluid typically air, is filtered through a filter 13, heated by a heat exchanger 14 and sent by a fan 4 in a distribution channel 5 sending it among the trays 3 on pieces 2, according to the path indicated by the small white arrows.
  • FIG. 9B shows a longitudinal section of the cooling chamber 74 of the oven 61 according to the known art.
  • a known air treatment group 30’ that, through an inlet, takes air 11’ from the environment, while it optionally recirculates air taken from the oven itself through an optional recirculating channel 10’.
  • Said cooling fluid typically air, is filtered through a filter 13’, possibly cooled by a heat exchanger 27’ and sent by a fan 4’ into a distribution channel 5’ distributing it among the trays 3 on pieces 2, according to the path indicated by the small black arrows.
  • Said cooling fluid flow is taken from the suction channel 7’ thanks to a fan 8’ or to the depression generated by the fan 4’ through the channel 10’ itself.
  • said fan 8’ can be optional, but is shown in order to ease the understanding of the system.
  • a percentage of air 9’ typically 100-40%) is exhausted, in order to allow air renewal for cooling the pieces 2.
  • the oven 61 comprises said air treatment groups 30, 30’, in their turn comprising, respectively:
  • a filter 13, 13’ for filtering the flows of air 11, 11’ and/or 12, 12’ or their mix;
  • air treatment groups 30, 30’ showing variations with respect to the above-described composition, without affecting the presented concepts.
  • the abovedescribed functions can be performed through components arranged in the oven without being aggregated in an air treatment group 30, 30’ that can be identified as a unit.
  • the fan 4, 4’ might be arranged upstream the filter 13, 13’, and/or the heat exchanger 14, 27’.
  • FIG. 10 shows an oven 400 according to the present invention.
  • the oven 400 comprises a system for treating air schematized as a unit 30, which provides air recirculation, comprising an inlet for recirculated air 12 and an inlet for air 11 coming from the environment; both inlets are typically provided with a shutter.
  • At least a heat pump 15 is added, so as to recover the heat otherwise dispersed in the environment by the exhaust airflow 9.
  • Said heat pump comprises in a known way an evaporator 16, a condenser 18, a compressor 17, an expansion valve 19.
  • an oven 400 according to the present invention is shown in its first air/water embodiment, wherein the drying fluid exhaust flow 9’ of the cooling chamber 74 coming from the fan 8’, is conveyed through a closed air duct to the heat pump 15 to release its heat to the evaporator 16; optionally air 22 taken from the environment may be added, so exhausting air 23 with a temperature lower than that of the air entering into the heat pump 15.
  • the expansion valve 19 the refrigerant fluid cooled off in the condenser 18 is brought back to a lower pressure and sent to the evaporator 16 again.
  • FIG 11 shows an alternative embodiment of an air/air oven 401, wherein the cooling fluid exhaust flow 9’ of the cooling chamber 74, preferably air, releases its heat directly to the evaporator 16, while an air flow 24 coming from the environment is heated passing through the condenser 18 configured as a heat exchanger, before entering into the air treatment group 30 through an air duct 25 and mixed with an air flow 12, dispensing with the hot water circuit 20, the heat exchanger 14 and the recirculating pump 21 according to the embodiments shown in the preceding Figures.
  • This embodiment has the least requirements from the plant point of view.
  • FIG 12 shows an alternative embodiment of a water/water oven 402, wherein there is provided an exchange intermediate fluid, e.g. water, circulating in two different circuits 20 and 28’ through pumps 21 and 26’ in heat exchangers 14 and 27’, wherein the recirculated cooling fluid flow 12’ released from the cooling chamber 74 releases its heat to the intermediate fluid, i.e. water, in the heat exchanger 27’ .
  • Said intermediate fluid releases the heat to the evaporator 16 configured as a heat exchanger and through the pump 17 of the heat pump transfers heat to the condenser 18 in its turn working as heat exchanger connected to circuit 20 for an intermediate fluid, e.g. water, that through the pump 21 circulates the intermediate fluid toward the heat exchanger 14 to heat the drying fluid inside the drying chamber 72.
  • an intermediate fluid e.g. water
  • the water/air embodiment is not shown for simplicity’s sake; here the heat transfer occurs between the condenser and the evaporator of the heat pump, respectively.
  • the condenser directly heats the drying fluid, preferably air, taken from the environment; to it, after having been in thermal contact with the condenser for heating, the portion of drying fluid that crossed the drying chamber, and was not exhausted from it (recirculated air) is mixed.
  • the evaporator recovers heat from said portion of cooling fluid exhausted from the cooling chamber; this occurs in an indirect way, as the heat subtracted from the pieces from the cooling fluid exhausted is used to heat said intermediate fluid, e.g. water, through a heat exchanger, while said heated water coming out from the heat exchanger is used as intermediate fluid to transfer heat to the refrigerant fluid of the heat pump through the evaporator configured as heat exchanger.
  • the temperature of the air used for drying pieces 2 is about 60-70°C; the temperature of cooling exhaust air 9’ coming from the fan 8’ is about 10°C higher than the temperature of the environment, unless a chiller is provided.
  • the heat pump 15 is supplied, in addition to the cooling fluid 9’ exhausted from the cooling chamber 74, with the exhaust portion of the drying fluid 9 of the drying chamber 72 too, further increasing the recovered energy.
  • an oven 403 comprising an air/water system recovering heat from the drying exhaust, by mixing the exhaust air 9 of the drying chamber 72 with the exhaust flow 9’ of the cooling chamber 74 before channelling them to the evaporator 16, and exhausting their mix as airflow 23 at a temperature lower than their ingress temperature.
  • an oven 404 comprising a water/water system recovering heat from the drying exhaust of the drying chamber 72, too, using two intermediate fluids through two circuits, the first circuit comprising the heat exchanger 27, the circuit 28 and the pump 26, and the second circuit comprising the cooling chamber 74 the heat exchanger 27’, the circuit 28’ and the pump 26’, the two intermediate fluids being sent to the evaporator 16 in order to release heat.
  • the energy of the drying fluid of the drying chamber 72 can be recovered by providing air/air and water/air systems that are not shown in Figures for simplicity’s sake, but that work according to the already described principles.
  • said heat pump 15 is placed so as to recover the heat of cooling chamber 74 of the oven 400, 401, or 402, optionally with the interposition of one or more heat exchangers working with an intermediate fluid, so as to recover the heat normally released outside the cooling chamber 74 through the cooling fluid before it is exhausted outside. Said heat is instead used to heat up the drying fluid of the drying chamber 72.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Drying Of Solid Materials (AREA)

Abstract

La présente invention concerne un four tunnel pour le séchage/vaporisation et le refroidissement de peintures/colles sur des pièces comprenant : • -au moins une chambre de tunnel de séchage ; • -au moins une chambre de tunnel de refroidissement comprenant éventuellement un échangeur de chaleur ; ladite chambre de tunnel de séchage et ladite chambre de tunnel de refroidissement comprenant : •a. au moins un système de transport • b. au moins un groupe de traitement de l'air comprenant : •-une entrée d'air recyclé ; •-une entrée d'air extérieur ; •-éventuellement un filtre pour flux d'air extérieur et/ou d'air de recirculation ou leur mélange ; •-un ventilateur fournissant lesdits flux d'air ou leur mélange dans la chambre de séchage ou de refroidissement ; • éventuellement un ventilateur d'échappement évacuant un flux de séchage ou de fluide de refroidissement ; • au moins une pompe à chaleur comprenant : un évaporateur, un compresseur, un condenseur, un détendeur et un fluide frigorigène, ledit évaporateur et condenseur transférant de l'énergie thermique entre le fluide frigorigène à l'intérieur de celui-ci et un autre gaz ou fluide ; ladite chambre de séchage et de refroidissement étant reliée à ladite pompe à chaleur.
PCT/EP2023/087737 2022-12-29 2023-12-22 Four de séchage à l'air avec économie d'énergie WO2024141506A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
IT202200027147 2022-12-29
IT102022000027147 2022-12-29
IT202200027144 2022-12-29
IT102022000027144 2022-12-29

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WO2024141506A1 true WO2024141506A1 (fr) 2024-07-04

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IT221807Z2 (it) 1991-04-10 1994-10-20 Cefla Coop Forno verticale a vassoi con tempo di permanenza regolabile dei pezzi in trattamento
IT1309018B1 (it) 1999-03-02 2002-01-15 Cefla Coop Forno verticale con possibilita' di funzionamento a ciclo breve.
EP2609021B1 (fr) 2010-08-24 2014-10-29 Hänel & CO. Système de rayonnage pour le stockage de produits à stocker
EP3117906A1 (fr) 2015-07-17 2017-01-18 Zachodniopomorski Uniwersytet Technologiczny w Szczecinie Cabine de peinture avec récupération de chaleur
WO2017158550A1 (fr) 2016-03-18 2017-09-21 Cefla Societa' Cooperativa Four vertical pour des pièces principalement plates
CN107843113A (zh) 2017-10-31 2018-03-27 广西旭腾实业集团有限公司 一种高效节能自动化辊道窑
CN109569989A (zh) 2018-11-09 2019-04-05 同济大学 使用热泵热回收和桶泵循环的锂电池极片涂布机烘干系统
CN109682206A (zh) 2018-12-13 2019-04-26 福建荣华科技有限公司 高效烧结炉以及磷酸铁锂生产装置
WO2019140862A1 (fr) 2018-01-16 2019-07-25 广州恒新创展科技有限公司 Four tunnel
CN210725526U (zh) 2019-11-15 2020-06-09 盐城天锐先锋电子科技有限公司 一种电路板烘烤箱
CN214440639U (zh) 2021-02-22 2021-10-22 江苏宇通干燥工程有限公司 一种烘干油漆用烘箱
EP3767215B1 (fr) 2019-07-19 2022-03-02 Wienerberger AG Installation de cuisson des ébauches d'ouvrages céramiques

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4173924A (en) 1978-03-01 1979-11-13 Schweitzer Industrial Corporation Paint spray booth with air supply system
GB2078651A (en) 1980-06-24 1982-01-13 Lienhard Ag Cabinet with two stacks formed of container units
IT221807Z2 (it) 1991-04-10 1994-10-20 Cefla Coop Forno verticale a vassoi con tempo di permanenza regolabile dei pezzi in trattamento
IT1309018B1 (it) 1999-03-02 2002-01-15 Cefla Coop Forno verticale con possibilita' di funzionamento a ciclo breve.
EP2609021B1 (fr) 2010-08-24 2014-10-29 Hänel & CO. Système de rayonnage pour le stockage de produits à stocker
EP3117906A1 (fr) 2015-07-17 2017-01-18 Zachodniopomorski Uniwersytet Technologiczny w Szczecinie Cabine de peinture avec récupération de chaleur
WO2017158550A1 (fr) 2016-03-18 2017-09-21 Cefla Societa' Cooperativa Four vertical pour des pièces principalement plates
CN107843113A (zh) 2017-10-31 2018-03-27 广西旭腾实业集团有限公司 一种高效节能自动化辊道窑
WO2019140862A1 (fr) 2018-01-16 2019-07-25 广州恒新创展科技有限公司 Four tunnel
CN109569989A (zh) 2018-11-09 2019-04-05 同济大学 使用热泵热回收和桶泵循环的锂电池极片涂布机烘干系统
CN109682206A (zh) 2018-12-13 2019-04-26 福建荣华科技有限公司 高效烧结炉以及磷酸铁锂生产装置
EP3767215B1 (fr) 2019-07-19 2022-03-02 Wienerberger AG Installation de cuisson des ébauches d'ouvrages céramiques
CN210725526U (zh) 2019-11-15 2020-06-09 盐城天锐先锋电子科技有限公司 一种电路板烘烤箱
CN214440639U (zh) 2021-02-22 2021-10-22 江苏宇通干燥工程有限公司 一种烘干油漆用烘箱

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