Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B3/00—Drying solid materials or objects by processes involving the application of heat
  • F26B3/28—Drying solid materials or objects by processes involving the application of heat by radiation, e.g. from the sun
  • F26B3/30—Drying solid materials or objects by processes involving the application of heat by radiation, e.g. from the sun from infrared-emitting elements
  • F26B3/305—Drying solid materials or objects by processes involving the application of heat by radiation, e.g. from the sun from infrared-emitting elements the infrared radiation being generated by combustion or combustion gases
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F5/00—Dryer section of machines for making continuous webs of paper
  • D21F5/001—Drying webs by radiant heating
  • D21F5/002—Drying webs by radiant heating from infrared-emitting elements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
  • F23D14/12—Radiant burners
  • F23D14/16—Radiant burners using permeable blocks
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23N—REGULATING OR CONTROLLING COMBUSTION
  • F23N5/00—Systems for controlling combustion
  • F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
  • F23N5/08—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using light-sensitive elements
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B3/00—Ohmic-resistance heating
  • H05B3/0033—Heating devices using lamps
  • H05B3/0038—Heating devices using lamps for industrial applications
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D2203/00—Gaseous fuel burners
  • F23D2203/10—Flame diffusing means
  • F23D2203/105—Porous plates
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D2212/00—Burner material specifications
  • F23D2212/10—Burner material specifications ceramic
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D2212/00—Burner material specifications
  • F23D2212/10—Burner material specifications ceramic
  • F23D2212/103—Fibres
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
  • H05B2203/032—Heaters specially adapted for heating by radiation heating

Definitions

• the present invention refers to a modular infrared irradiation apparatus which employs combustion gas and its respective monitoring devices.
• the apparatus of the present invention is direcetd to thermal transfer operations for provide quick and efficient thermal energy transfers at high rates as in industrial drying operations of paper making and cellulose industries.
• the irradiation apparatus comprises automation means for control the starting and all steps of the procedure which is performed by such equipment and permits multiple industrial applications.
• a drying step (or a set drying steps distributed along the process) is a necessary step for drying coating or impregnating substances added to the product.
• IR drying techniques employ heat transfer by direct contact between the heat receiver and the planar and/or cylindrical heat source or by means of hot air blowing.
• the Infrared (IR) drying technique is the most preferred because the direct contact step for heat transfer is avoided.
• this embodiment normally employed for complementary drying applications in the traditional drying steps of the art.
• the desired result e.g., substrate features, and surface and phisical properties
• the desired result e.g., substrate features, and surface and phisical properties
• the IR technique has particular features and such features make the difference when applied to known heat irradiation apparatus of the art.
• the IR generation techniques are basically distinguished in the temperature average and in the frequence range of the irradiating element.
• the selection of building materials determines the IR emission ability of such apparatus in some ranges of frequence, i.e., metallic irradiation elements generate long and medium waves. Ceramic irradiation elements at high temperatures generate short and medium waves. Generally, short waves have best penetration features in substrates in relation to long waves, and it permits that a substrate be dried without direct contact and avoinding damage to the dried substrate surface.
• the eletromagnetic energy produced at IR frequence bands if correctly set, will be absorved by substrate in such manner that the material will change, firstly in its initial state by absorbing heat and modifying its temperature. For volatile substances like water, the absorbed heat permits the chance of phisical state, from liquid to vapor, and thus the drying step occurs by evaporating all volatile mass contained in the substrate.
• the amount of water to be evaporated from the substrate is a particular feature of the product and depends on the manfacturing route and the final application of such product. Therefore the intensity of thermal energy in each case is to be particularly determined.
• IR use as a final controller of remaining volatiles in the substrate, e.g., the substrate humidity, is an alternative that depends of the irradiation element. If the element is able (or not) to change the heat emission power the process is able to dry the substract at the desired level.
• irradiation models as mentioned above are known in the art. Most of them comprise a metallic frame which enclose irradiation elements into metal housings, such elements are installed side by side transversally or alongside of the process direction.
• the irradiation elements are positioned near to the substrate path and at least one plenum air and/or air/combustible gas mixture distributor is provided. Irradiation elements are positioned at a minimal distance from the substrate path in order to obtain a maximum of heat transfer efficiency and avoid unnecessary substrate distortions, e.g, cause wet bands in the substrate due to the temperature differences of the housings in relation to the irradiation elements.
• the systems of the art generally employ a not standard combustible gas mixture composition. Such differences can alter the burning stoichiometry at the irradiation elements. So, the flame can return to the inner part of the equipment at the plenum zone or at the gas injection tips and cause explosions and the process is to be interrupted for repairs for long term.
• Ducts occupy a considerable space in the production plant and it reduces a best employment of the plant space and makes a new equipment installation dificult.
• Some recent techniques employ irradiation elements made of continous refractory ceramic plates as a radiation emitter. Such plates are designed for cover all width of the process and are longitudinally positioned at one or more sections. Such arrangement comprises a limitation when the process is to be fitted for other ends.
• the present invention provides a modular IR irradiation apparatus which employs combustion gas and its respective integrating devices for automatically control the air/gas mixture, for sequencing the process starting, for interlocking the equipment and the corresponding process.
• the fibrou ceramic have flexible pores through which the air/gas mixture flows and after the air/gas mixture emerges from an escape surface an ignition means is driven and a fire line provided and kept stable over the ceramic escape surface which acts as IR irradiation element at high frequency bands.
• This preferred embodiment permits a safe operation, because the flexible fibrous ceramic does not resist to pressure, causing minimal intensity explosions and provides soft fragments when exploded.
• the modular design permits multiple arrangements being fitted to any drying processes, enhances the continous irradiation element operation.
• Thermal sensor- safety device applied in the lower face of each flexible fibrous ceramic module, more particularly fixed in the support screen of the ceramic plate and extending to median line of such plate, for monitoring a possible heat flow inversion due to external factors which cause the "flame swallowing".
• a heat reflection means positioned in front of the irradiation element in order to return IR energy back to the irradiation element and creating an ressonance effect for store heat in the irradiation element and make the flow inversion.
• Oxygen measuring means - Continous measuring based on Zirconinum oxide.
• This device collects combustion gases over the burning surface in at least one module of refractory ceramic, for continous analysis ends, permitting a flame optimization e an after buring residual oxygen controlling.
• Such sensor is connected to a LPC ( Logical Program Controller) of the monitoring, interlocking and alarming system which is driven when the level of oxygen does not match with the standard value.
• LPC Logical Program Controller
• UV Flame detector It is applied in the external face of the metallic frame, more particularly, near to the combustible gas inlet, for flame detection, i.e., for combustion detection in the ceramic modules.
• the flexible ceramic concentrates the burning in its surface, the IR generation occurs basically in the short waves range, including some residue at the begining of the UV spectrum which is identified by the UV detector.
• the UV detector is assembled as an cathode anode discharge vessel, known in the art, inserted in a housing or specially designed device for support severe operation conditions.
• the housing have a cylindrical shape made of metallic material provided with a lower hole and channels for better air circulation. Refrigeration air flows from refrigeration ribs and also from the ceramic discharging tube of the receptacle body of the sensor, keeping the inner pressure positive and external particulate material entrance is avoided (the equipment can use two UV flame detector);
• Bed - ail flexible refractory ceramic modules and the first and the second plenum distribution means are positioned in the bed which is made of metallic plates having two handles and two mirrors and botton caps and couterventing strips. Between the handles and the bottom caps a safety system is provided for permit an easy opening of the caps for maintenance or for avoid bed expanding in case of explosion. The locking system permits determine the effects of an explosion.
• novel modular IR irradiation means and its eletronic devices permit a better control during the operation and an enhanced global efficiency for thermal energy.
• - LPC can be programmed for logoff some modules when other are still active and meet substrate width variations requirements.
• the fiber web has some anisotropic free grade related to a particular moviment.
• the average pore diameter is automatically adjusted for keep balance between the pores. This permits a gas volume and the power level modulation and keep the discharge rate controlled and fitted to the minimum limit.
• the oxygen measuring means application makes possible the residual smoke collection after the burning for continous monitoring of the residual oxygen and this system can detect failure in the combustible gas feeding.
• Other feature of such means is that it is able to keep a high burning efficiency and keep the previous defined stoichiometry for obtain the desired temperature and IR band results.
• the metallic frame building having inner pressure rate and overpressure alleviating means meets the safety requirements as the explosionproof equipment, providing a safe operation for workers and equipment.
• Figure 1 is a perspective view of the modular heat irradiation element provided with some irradiation modules in ready to use position and one module in exploded view;
• Figure 2 is cross sectional view of the IR irradiation element of the present invention
• Figure 3 is exploded perspective view of a irradiation module, illustrating all its components;
• Figure 4 is a sectional view of an oversized detail of the stopping means in the ceramic plate;
• Figures 5 and 6, illustrate, respectively, side and sectional views of the irradiation module;
• Figure 9 is a cross sectional view of the bed, showing the mounting system with safety device for alleviating the explosion;
• Figure 10 is an oxygen measuring means, in a more detailed perspective view;
• Figure 11 illustrates the oxygen measuring means mounted on the IR modular irradiation element
• Figure 12 is an exploded perspective view of the UV sensor bulbs support housing
• FIG. 13 is sectional view of the UV flame detector of the invention. DETAILED DESCRIPTION OF THE INVENTION
• the present invention refers to a MODULAR INFRARED IRRADIATION APPARATUS AND ITS CORRESPONDING MONITORING DEVICES
• the modular heat irradiation apparatus (1) is directed to heat transfer operation involving elevated rates of heat to be contoinously traferred to a receiving substrate, e.g., industrial drying process of fibrous products as paper or cellulose (L) ( Figure 2).
• the modular heat irradiation apparatus basically comprises a metallic frame or bed (2) which is designed for receive a number of irradiation modules (7), according to process width and in such manner to receiver distribution and support ducts, priamary plenum (3p), secondary plenum (3s) which possesses gas/ar (G) mixture feeding outlets (3a) to the modules (7).
• priamary plenum (3p) which possesses gas/ar (G) mixture feeding outlets (3a) to the modules (7).
• the employment of two plena having rectangular shape (3p and 3s) serve as mechanic support fo the modules (7) in order to position them in such manner to permit the gas/air mixture (G) feeding in the modules (7) by means a modulation/blocking valve (VL) coupled to the primary plenum (3p) or blocking free directly coupled to the secondary plenum (3s).
• VL modulation/blocking valve
• the module presents an unique mixture (G) inlet (4) whic can be positioned aligned to the primary plenum (7v) or secondary plenum (7d), depending on the final application which can be defined by turning the module 180° and by opening passageway (3a) of the primary plenum (3p).
• the bed (2) is made of two mirror joining (LI/LC) having lower laterals (LI) and axle type fixing supports (4) (Figure 1) which are fixed to the processes by means of locking bearings (M), permitting adjsutment of the equipment angle at the moment of the installation in relation to substrate flow direction (L).
• the bed has the upper side (LS) comprising lateral channels for alleviating thermal dilatation (AD) and resist to temperature variations between the upper edge and the lower edge and receiving refractory material (MR) to the irradiated IR, in order to define one irradiation cavity(CR), joined the frontal face, which is provided with irradiation modules (7).
• modules (7) are trasnversally positioned to the longitudinal axle of the bed (2) and arranged side by side in order to define a regular planar surface.
• the bed is further closed by metallic caps (6) which description will be provided after.
• the mirror (El) of the bed (2) ( Figure 1) is provided with sealing air inlet duct (AS) for keep the inner cavity of the equipment pressurized and refrigerated; such air inlet has an independent feeding and is directed to avoid entrance and storing not desired materials and gases in the cavity, protecting the frame against gas losses.
• the pressurized air is directed to UV system refrigeration and venturi system, both detailed in the present appliation.
• Irradiating modules (7) can be made in variable dimensions and width, and according to Figures 3,4,5 and 6 each one of the irradiation modules(7) is made of metallic material base receiver( ⁇ ), containing a feeding hole (9), positioned and not centrallized in relation to the surface of such base, for aligning with other plenum support (3p/3s) at the moment of the mounting, just inversing the module according to the plenum.
• the mounting at the side of the plenum (3p or 3s) is achieved employing a stopping ring (11) fitted to the feeding hole (9), which ring permits a good positioning of the module when the fixation occurs over the distribution plena (3p, 3s) and each module (7) is fixed in the plena by screws restraining pins (P).
• the base (8) receives at its free edge, a screen (12) containing holes (12a) having suitable dimensions and shapes, in the lower face of the screen (12) are fixed at least two sets of sensors of thermal flow (14) interconnected by the electronic circuit (13); such sensors extend over the screen to deep contact the penetration layer of the ceramic (15) where the sensors are fixed thereto.
• the sensors are interconnected to an electronic device (14a), which is connected to the LPC central, not shown.
• each refractory flexible ceramic plate (15) ( Figure 4) is made of sealing means (S) which are high temperature resistant and arranged in thin ceramic housings (16) and placed at the side faces of the ceramic plate by means of a high temperature resistant elastomer (17) layer( Figure 4) which is able to penetrate between the parts (15, 16) in order to produce and anchoring phenomena, adhering to said parts and avoiding lateral dispersions (D) of combustible gas in the ceramic plate through the screen holes (12a) by stopping them. This keeps the burning zone restricted to the face (D1) in the surface of the ceramic plate (15).
• the block comprising the flexible refractoryceramic plate and the thin ceramic housings (16) are fixed to the screen (12) by means of an elastomer layer (17) suited to high temperatures, complementing the sealing means of the irradiation modules (7) and producing a flexible joint which supports natural vibrations which occur during the operation of the equipament and fit different materials possessing very thermal dilatation coeficients, i.e., the different ceramic materials and the metallic carcass.
• the refractory ceramic plate 15
• the flexible pores see detail A in Figure 3
• this free movement feature permits a dynamical distribution of the gas flow through the pores (R) of the fibrous structure, thus making the pores open and/or closed when necessary, depending on the use condition and keeping the balance between them.
• the gas volume flowing through the ceramic plate is able to be modulated and the emission power of the irradiation element is indirectly modulated by varying the combustible gas volume (G), but keeping active the discharge rate of the pores compatible to the combustion rate, therefore, the flame is stably positioned at the first layers (D1) of the flexible ceramic.
• Another property of the ceramic plate associated to the flexibility feature and not affected by erosion is the ability of the irradiation element resist to dropping contamination, e.g., ink dorps in a continous painting process of paper.
• the drop material at the surface of the irradiation surface can be easily removed by mechanic procedures of scratching or abrasion avoiding other cleaning procedures and the system is quickly restored.
• the bed (2) ( Figures 1 ,2 and 8) as previously stated, is made of lower side metallic plates (LI) having angular flaps (18a), closing mirrors, blind mirror (EC) and instrument mirrors (El) having holes suited to the devices to be fixed therein and botton caps (6) having side flaps (6a) e closing flaps (22 and P1); such side plates (LI) are alterned with counterventing channels (21) while the botton caps (6) have one flap (22) at one side fixed by engaging to one of the LI flaps (18), and at the other side, the flap is fixed by means of screws (P1), therefore is provided one safety devide between the lower side plates (LI) and the bottom cap (6), the particular geometry feature of the caps permits that the flaps (18, 22) be easily unlocked offering an escape area for gases, in the case of internal explosion, the cap (6) is fixed to the structure by means of the screws (P1) for permitting the removal of the cap for maintenance ends.
• Modular heat irradiation apparatus (1) is equiped with automatic lighting devices and monitoring means, which are interconnected to the LPC, not shown, such devices comprise the trigger (CT) and sensors of thermal flow (14), oxygen measuring means (23), and the UV sensor (Figure 13), better detailed ahead.
• CT trigger
• sensors of thermal flow 14
• oxygen measuring means 23
• UV sensor Figure 13
• Automatic lighting system comprises the assembling of some trigger electrodes (CT).
• CT trigger electrodes
• the lighting is produced by inonizing the air by using a high tension source which discharges over the bed (2).
• the triggers are mounted in a number which is enough for permit the lighting of the irradiation element even part of such triggers are disabled.
• Thermal flow sensor (14) which position has been previously detailed, is the responsible for monitoring de heat flow inversion, since each sensor (14) monitores a maximum temperature differential between the median line (Y) of each ceramic plate (15) and the temperature of the feeding gas of the module, the verification occurs at the LPC for turn the equipment off when the differential is greater than maximum permitted limit, this would indicate thermal flow inversion, i.e., the flow is returning to the gas plenum and probably an explosio would occur.
• the thermal flow sensor is also used to indicate an erosion process in the ceramic plate and the replacement of such plate is necessary.
• the Oxygen measuring means (23) (Figuras 10 and 11) employ, a sensor (26) based on Zirconium oxide, which is positioned in one device containing a temperature controlled chamber (26) (temperature control system not inidicated), and such device is formed by five tubular bodies (27, 28, 30, 31 and 33) welded (29) one to the other, the set (23) is fixed by a holder (34) positioned in the inner flap of the upper side (LS).
• An extension is fixed to the tubular body (28) forming a venturi type system (30), the tube (30) having the greatest diameter conducts the sealing pressurized air inside the bed to outside.
• the sealing air passes between the tube (30) and the broader section of the tube portion (31) it is accelerated in order to effect vacuum inside the portion (31) and in the body (28), providing a vacuum chamber, while the collector tube (33) conducts the smokes collected in the inner part of the chamber (28).
• the collection tip (35) is coupled to the upper portion of the tube (33) and holes and the concetrating flaps (37) are provided in the lower part (36) of such tip.
• the lighting system also employs the the tip (35) as ground contact for discharge the trigger.
• the oxygen measuring means (23) is applied near to the burning zone, (D1) in order to continuous analyze the combustion of the irradiation element, optimizing the burning and controlling the amount of residual oxygen after the combustible burning.
• Such sensor is connected to the LPC of the monitoring system. Parameters of operation are adjusted in view of the desired application and the kind of combustible gas is used.
• UV detector (24) (illustrated in Figure 1 and more detailed in Figures 12 and 13) can be double assembled, i.e., two flame detector (24) can be for each irradiation element (Figura 1), each detector has an UV sensor bulb which is commecially available and its respective encapsulating system (39) installed inside the cooling system (40) extending to collimation cavity of IR emission (CR) by a ceramic bulb (47) restricting and protecting the sight of the bulb and the sight field against obstructing clouds of vapor from the process or against UV emissions from other external sources.
• UV sensors (24) are positioned at the external side of the the instrument mirror (El), more particularly fixed to the supports (44) which are fixed by tubes which are employed to conduct the pressurized sealing air inside the support tube fromthe irradiation element (4) to the cooling body (40).
• Each set of UV detector (24) additionally comprise a cooling body (40) having ribs (41) at its external face in order to provide cooling channels for keep the internal housing chamber (42) of the sensors (38, 39) cool; such protection comprises a lower hole (43) which is coupled to the metallic box type support (44) through which cooling air and connection wires of the electronic excitation and monitoring (called flame relay) are conducted.
• the ceramic protector tube (47) is fixed to the cooling body (40) by the flange (45) which possesses inner tips as restraining means (46) of such tube (47).
• irradiation modules the monitoring performed by the sensors and measuring means via discrete electronic controls or LPC
• the modular heat irradiator and its improved shape a high efficiency of the heat transfer between the irradiating surface and the receiving substrate
• the equipment designed for being easily adapted in any industrial process and all remedial effect achieved by this means which permit remarked improvements in the volatile removal from substrates, particularly wet removal from paper ou cellulose drying processes and the invention concept which permits a long term use of the equipment of the present invention and reducing maintenance interruptions.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Microbiology (AREA)
• Physical Or Chemical Processes And Apparatus (AREA)
• Photometry And Measurement Of Optical Pulse Characteristics (AREA)
• Control Of Combustion (AREA)

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• 2003
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  • 2003-11-07 EP EP03810345A patent/EP1587985A1/en not_active Withdrawn
  • 2003-11-07 KR KR1020057008265A patent/KR20050061603A/ko not_active Application Discontinuation
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