EP0253024A1 - Four de séchage ou de traitement avec circulation transversale réversible - Google Patents

Four de séchage ou de traitement avec circulation transversale réversible Download PDF

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Publication number
EP0253024A1
EP0253024A1 EP86201280A EP86201280A EP0253024A1 EP 0253024 A1 EP0253024 A1 EP 0253024A1 EP 86201280 A EP86201280 A EP 86201280A EP 86201280 A EP86201280 A EP 86201280A EP 0253024 A1 EP0253024 A1 EP 0253024A1
Authority
EP
European Patent Office
Prior art keywords
duct
oven
ducts
air
chamber
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP86201280A
Other languages
German (de)
English (en)
Inventor
Robert E. Hengle
William F. Granfors
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Feco Engineered Systems Inc
Original Assignee
Feco Engineered Systems Inc
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
Priority to US06/678,969 priority Critical patent/US4603491A/en
Application filed by Feco Engineered Systems Inc filed Critical Feco Engineered Systems Inc
Priority to EP86201280A priority patent/EP0253024A1/fr
Publication of EP0253024A1 publication Critical patent/EP0253024A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B9/00—Machines or apparatus for drying solid materials or objects at rest or with only local agitation; Domestic airing cupboards
    • F26B9/02—Machines or apparatus for drying solid materials or objects at rest or with only local agitation; Domestic airing cupboards in buildings
    • 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
    • F26B21/022—Circulating air or gases in closed cycles, e.g. wholly within the drying enclosure with provisions for changing the drying gas flow pattern, e.g. by reversing gas flow, by moving the materials or objects through subsequent compartments, at least two of which have a different direction of gas flow
    • F26B21/028—Circulating air or gases in closed cycles, e.g. wholly within the drying enclosure with provisions for changing the drying gas flow pattern, e.g. by reversing gas flow, by moving the materials or objects through subsequent compartments, at least two of which have a different direction of gas flow by air valves, movable baffles or nozzle arrangements
    • 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
    • F27B17/00—Furnaces of a kind not covered by any preceding group
    • F27B17/0016—Chamber type furnaces
    • F27B17/0083—Chamber type furnaces with means for circulating the atmosphere
    • 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
    • F27D7/00—Forming, maintaining, or circulating atmospheres in heating chambers
    • F27D7/04—Circulating atmospheres by mechanical means

Definitions

  • the present invention relates to an oven for drying or curing articles and particularly relates to a reversible, convection air, cross flow drying or curing oven. More particularly, the present invention relates to a drying or curing oven providing for manual or automatic reversal of cross flow convection air currents within the oven at periodic intervals to obtain uniform drying or curing characteristics substantially throughout the entirety of the oven.
  • This variance in temperature within the oven chamber is particularly critical in drying or curing flat sheets, for example, capacitor components which may vary in size from 81 ⁇ 2 inches by 11 inches to 4 feet by 8 feet. Flat sheets will often warp, crack or otherwise distort when hot air at different temperatures is applied over the entirety of the surface of the sheets. Moreover, it will be appreciated from the foregoing that the optimum oven residence time for proper drying or curing of workpieces in batch type ovens is not dependent on the workpiece which first dries or cures. Rather, if all the workpieces are to be dried or cured, the residency time for all workpieces within the oven is dependent on the workpiece which last dries or cures.
  • economy of oven operation is sacrificed in those batch type ovens where temperature gradients exist if all workpieces are to be entirely dried or cured over the proper period of time.
  • economy of oven operation is affected by the temperature necessary to dry or cure the workpieces.
  • the temperature of the incoming air is usually higher than necessary in order that the workpieces closest to the return will be dried or cured at the designed temperature.
  • heated air must be supplied at non-optimum; e.g., higher, temperatures. The operation of the oven therefore requires substantially greater energy input than would be necessary if uniform temperatures could be maintained throughout the oven chamber.
  • a reversible cross flow drying or curing oven including an oven housing having opposed side walls defining a drying or curing chamber therebetween for receiving articles to be dried or cured, first and second ducts disposed along the respective opposite side walls of the housing and having openings for transmitting air into and out of the oven chamber, means for supplying heated air into and out of the oven chamber, means for supplying heated air to the first and second ducts for transmission thereof into the oven chamber through the openings of the associated duct, means including the first and second ducts and their associated openings for returning air from the oven chamber to the supply means, and control means in the supply means and the return means for alternating the supply of heated air through the first duct and the second duct into the oven chamber and alternating the return of air out of the oven chamber through the second duct and the first duct, respectively, thereby establishing a flow of heated air alternately in opposite
  • a reversible cross flow drying or curing oven comprising an oven housing having opposed side walls defining a drying or curing chamber therebetween for receiving articles to be dried or cured, first and second ducts disposed along the respective opposite side walls of the housing and having openings for transmitting air into and out of the chamber, means for supplying heated air to the first and second ducts including first and second supply ducts, respectively, and a heater, means for returning air from the first duct and the second duct to the supply means including first and second return ducts, respectively, a damper in each of the first and second supply ducts and the first and second return ducts movable between a position substantially closing the associated duct from air flow and a position opening the duct to air flow, and means connected to each damper for moving the damper between its duct closed and its duct open positions, whereby opening the dampers in the first supply duct and the second return duct and closing the dampers in the second supply duct and the first return
  • Oven 10 includes a generally box-like housing 12 having side walls 14, and end walls 16, and a top wall 18. Doors 20 are hingedly mounted on each of the opposite end walls 16, and open outwardly to provide access to the interior of oven 10 from opposite ends thereof.
  • Articles for drying or curing, such as workpieces, may be carried on racks, schematically illustrated at 15, mounted on rollers whereby the articles may be rolled through open doors 20 at one end of oven 10 into the ovens heat chamber, generally designated 22, defined between side and end walls 14 and 16, respectively, and below top wall 18.
  • oven 10 is useful for drying or curing articles in a continuous batch type process.
  • oven housing 12 On top of oven housing 12 is a cupola 24 housing mechanicals and ductwork described hereinafter.
  • the interior of oven 10 is provided with an air circulating system comprised of ductwork including first and second elongated, generally horizontally extending, ducts 26 and 28, respectively, disposed along the respective opposite side walls 14 of housing 12.
  • Ducts 26 and 28 are spaced laterally one from the other and further define therebetween the heat chamber 22.
  • Each duct 26 and 28 includes a plurality of openings or apertures 30 longitudinally spaced one from the other along its inwardly facing wall for flowing air into or out of heat chamber 22 in a manner described hereinafter.
  • Each opening 30 is provided with adjustable louvers 32 which control the rate of flow of heated air into and out of oven chamber 22 as well as its direction when flowing into chamber 22. Louvers 32 may be manually adjusted for each drying or curing operation in accordance with the characteristics of the articles to be dried or cured.
  • supply duct 34 includes a main supply passage 38 and a pair of downwardly directed, supply passageways 40 and 42 in communication at their upper ends with the respective opposite ends of main supply passage 38.
  • Supply passageways 40 and 42 communicate at their lower ends, with first and second side ducts 26 and 28, respectively.
  • Communication between supply passageways 40 and 42 and ducts 26 and 28 is controlled by suitable flow control devices, such as dampers 44 and 46, respectively.
  • flow of air through main supply passage 38 may be directed to one or the other of side ducts 26 and 28 through its corresponding passageways 40 or 42 by operating supply dampers 44 and 46 to close or open the passages therebetween.
  • Return duct 36 includes a main return passage 48 and a pair of downwardly directed passageways 50 and 52 in communication at their upper ends with the respective opposite ends of main return passage 48.
  • Return passageways 50 and 52 communicate, at their lower ends, with first and second ducts 26 and 28, respectively.
  • Communication between return passageways 50 and 52 and ducts 26 and 28 is similarly controlled by suitable flow control devices, such as damper 54 and 56, respectively.
  • damper 54 and 56 suitable flow control devices
  • flow of return air from one or the other of ducts 26 and 28 may be directed to main return passage 36 through the associated return passageway 50 or 52 by opening the corresponding dampers 54 or 56.
  • return flow of air from one or the other of side ducts 26 and 28 may be blocked from returning to main return passage 36 by closing the associated damper 54 or 56.
  • each damper is controlled by an associated air cylinder 44a, 46a, 54a, and 56a.
  • a supply line 51 provides air under pressure from a supply source 53 through a four way, two position, solenoid actuated, spring returned valve 55, the solenoid and spring being designated 57 and 59, respectively.
  • valve 55 air is supplied cylinders 44a and 56a to retract the associated pistons and consequently rotate, through an appropriate linkage, not shown, dampers 44 and 56 to their illustrated open positions.
  • air supplied cylinders 46a and 54a extends the associated pistons and consequently rotates, through an appropriate linkage, not shown, dampers 46 and 54 to their illustrated closed positions.
  • valve 55 By energizing solenoid 57, valve 55 is shifted.
  • air is supplied cylinders 46a and 4a to retract the associated pistons and close dampers 46 and 54.
  • air is supplied cylinders 44a and 56a to extend their associated pistons and open dampers 44 and 56.
  • the dampers operate in pairs; i.e., a supply and a return damper, each on opposite sides of the oven chamber from the other, are always open or closed, while the other pair of the supply and return dampers on opposite sides of the oven chamber are always closed or open, respectively.
  • cupola 24 comprises a generally box-like housing 60 secured above both cross over main supply and return passages 34 and 36, respectively. Openings 62 and 64 are provided through the tops of ducts 34 and 36, respectively. Thus, communication is provided between the interior of cupola 24 at one end thereof with supply duct 34 through opening 62 and at its opposite end with return duct 36 through opening 64. Disposed between openings 62 and 64 and within cupola housing 60 is a heater 66. Heater 66 may comprise any conventional heating element, such as a steam heating coil with suitable external connections to a source of steam, or an electric heating coil suitably connected to a source of electric current.
  • heater 66 is removably mounted within cupola housing 66 by means of an access door, not shown, in the side of housing 60.
  • a recirculating fan 70 driven by a motor 72 mounted externally of cupola housing 60.
  • a series of adjustable openings 74 are at the rear end of cupola housing 60. Openings 74 permit the fan to drawing atmospheric air into the air circulating system, as needed to make up for hot air loss during the operation of the oven, which will now be described.
  • the articles to be dried or cured are loaded on racks and disposed within the oven chamber 22 through the open doors 20 at one end of oven housing 12. With doors 20 closed and the adjustable louvers 32 set as desired for the particular drying or curing operation, heater 66 and fan 70 are energized.
  • heated air is provided in oven chamber 22 in an alternating cross air flow pattern. That is, heated air is directed to flow from one side duct; e.g., duct 26, toward the other side duct; e.g., duct 28, for a predetermined time period.
  • the heated air is directed to flow from the other side duct; e.g., duct 28, toward the one side duct; e.g., duct 26.
  • the direction of the cross over air flow pattern is thus reversed within oven chamber 22 at periodic intervals. Consequently, temperature gradients resulting from heated air flow in one direction across chamber 22 are evened out by the heated air flow across oven chamber 22 in the opposite direction resulting in application of heat to articles undergoing the drying or curing process at a substantially more constant temperature and more uniformly throughout oven chamber 22. This enables substantially even drying or curing of the articles regardless of their orientation and location within the oven chamber 22 and minimizes or eliminates the danger of cracking, warping or otherwise distorting the articles.
  • air is supplied through valve 55 as illustrated in FIGURE 5 to cylinders 44a and 56a to open the corresponding dampers 44 and 56 enabling communication between main supply passage 34 and duct 26 on the supply side and communication between main return 36 and duct 28 on the return side.
  • air is supplied through valve 55 to cylinders 46a and 54a to close the corresponding damper 46 and 54 preventing communication between main supply passage 34 and duct 28 on the supply side and communication between main return 36 and duct 26 on the return side. Consequently, heated air is suctioned by fan 70 in cupola 24 through heater 65 and directed through opening 62 into main supply passage 34.
  • the heated air flows through supply passageway 40 into duct 26 and outwardly thereof through openings 30 in duct 26 into oven chamber 22.
  • the air thus crosses in chamber 22 from duct 26 to duct 28 and enters the latter through the openings 30 in its side wall.
  • this return air flows past open damper 56 into return passageway 52 and main return passage 36 and through opening 64 into cupola 24.
  • the closed dampers 46 and 54 prevent reverse flow of supply air through supply passageway 42 into duct 28 and reverse flow of return air through return passageway 50.
  • a cross flow of heated air from duct 26 across the oven chamber 22 to duct 28 is established and continues for a predetermined time interval. At the end of this time interval, the direction of the flow across the chamber is reversed.
  • cylinders 46a and 54a are actuated by shifting valve 55 to its other position thereby closing dampers 46 and 54.
  • heated air is thus supplied oven chamber 22 by flow through opening 62 into main supply passage 34 and supply passageway 42, and past the open damper 46 into duct 28 for outflow through openings 30 into oven chamber 22.
  • the air in oven chamber 22 is returned by flowing through openings 30 into duct 26, into main return passage 36 via open damper 54 and return passageway 50 and through opening 64 into cupola 24.
  • a cross flow of heated air from duct 28 across oven chamber 22 to duct 26 is established.
  • the cylinders controlling the dampers are under the control of a single two position, solenoid actuated, spring returned valve 55.
  • Actuation of the solenoid may be accomplished manually or automatically.
  • the solenoid may be coupled to an electrical circuit having a current supply and a manually actuated switch with a releasable mechanical hold.
  • closing the switch, and mechanically holding the switch closed will cause a supply damper and a return damper on opposite sides of the oven to open while maintaining the other of the supply damper and the return damper on opposite sides of the oven to close. This establishes a heated air flow pattern across chamber 22 in one direction.
  • the switch is manually opened to permit the valve to spring return it its other position.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Drying Of Solid Materials (AREA)
EP86201280A 1983-05-05 1986-07-18 Four de séchage ou de traitement avec circulation transversale réversible Withdrawn EP0253024A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US06/678,969 US4603491A (en) 1983-05-05 1984-12-06 Reversible cross flow drying or curing oven
EP86201280A EP0253024A1 (fr) 1986-07-18 1986-07-18 Four de séchage ou de traitement avec circulation transversale réversible

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP86201280A EP0253024A1 (fr) 1986-07-18 1986-07-18 Four de séchage ou de traitement avec circulation transversale réversible

Publications (1)

Publication Number Publication Date
EP0253024A1 true EP0253024A1 (fr) 1988-01-20

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Application Number Title Priority Date Filing Date
EP86201280A Withdrawn EP0253024A1 (fr) 1983-05-05 1986-07-18 Four de séchage ou de traitement avec circulation transversale réversible

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EP (1) EP0253024A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2632714A1 (fr) * 1988-06-10 1989-12-15 Monteiro Daniel Four de sechage a air chaud pour la deshydratation de fruits ou legumes disposes sur des chariots a claies superposees, notamment pour la transformation de prunes vertes en pruneaux
CN113865299A (zh) * 2021-09-22 2021-12-31 肇庆市昊达机电设备有限公司 一种热风循环排胶箱

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR986549A (fr) * 1949-03-11 1951-08-01 Perfectionnements aux séchoirs à bois
FR1096725A (fr) * 1955-06-23
CH314071A (de) * 1953-05-23 1956-05-31 Robert Aebi & Cie Ag Einrichtung zum Umkehren der Strömungsrichtung der Luft in Trocknereiräumen
FR2288281A1 (fr) * 1974-10-15 1976-05-14 Chanjin Expl Des Ets Etuve de sechage
US4098008A (en) * 1976-11-08 1978-07-04 Wellons, Inc. Dry kiln having bidirectional air flow with unidirectional fan rotation
EP0011450A1 (fr) * 1978-11-13 1980-05-28 Knud Simonsen Industries Limited Dispositif pour inverser un courant d'air
EP0017665A1 (fr) * 1979-04-09 1980-10-29 KELLER OFENBAU GmbH Dispositif pour le séchage rythmique d'articles céramiques moulés
US4344237A (en) * 1979-12-13 1982-08-17 A.P.M. Wood Products Pty. Ltd. Wood drying kiln
US4603491A (en) * 1983-05-05 1986-08-05 Feco Engineered Systems, Inc. Reversible cross flow drying or curing oven

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1096725A (fr) * 1955-06-23
FR986549A (fr) * 1949-03-11 1951-08-01 Perfectionnements aux séchoirs à bois
CH314071A (de) * 1953-05-23 1956-05-31 Robert Aebi & Cie Ag Einrichtung zum Umkehren der Strömungsrichtung der Luft in Trocknereiräumen
FR2288281A1 (fr) * 1974-10-15 1976-05-14 Chanjin Expl Des Ets Etuve de sechage
US4098008A (en) * 1976-11-08 1978-07-04 Wellons, Inc. Dry kiln having bidirectional air flow with unidirectional fan rotation
EP0011450A1 (fr) * 1978-11-13 1980-05-28 Knud Simonsen Industries Limited Dispositif pour inverser un courant d'air
EP0017665A1 (fr) * 1979-04-09 1980-10-29 KELLER OFENBAU GmbH Dispositif pour le séchage rythmique d'articles céramiques moulés
US4344237A (en) * 1979-12-13 1982-08-17 A.P.M. Wood Products Pty. Ltd. Wood drying kiln
US4603491A (en) * 1983-05-05 1986-08-05 Feco Engineered Systems, Inc. Reversible cross flow drying or curing oven

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2632714A1 (fr) * 1988-06-10 1989-12-15 Monteiro Daniel Four de sechage a air chaud pour la deshydratation de fruits ou legumes disposes sur des chariots a claies superposees, notamment pour la transformation de prunes vertes en pruneaux
CN113865299A (zh) * 2021-09-22 2021-12-31 肇庆市昊达机电设备有限公司 一种热风循环排胶箱

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Inventor name: HENGLE, ROBERT E.