US2224895A - Double deck continuous kiln - Google Patents

Double deck continuous kiln Download PDF

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US2224895A
US2224895A US258893A US25889339A US2224895A US 2224895 A US2224895 A US 2224895A US 258893 A US258893 A US 258893A US 25889339 A US25889339 A US 25889339A US 2224895 A US2224895 A US 2224895A
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kiln
rolls
goods
moved
chamber
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US258893A
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Frank W Brooke
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SWINDELL DRESSLER CORP
SWINDELL-DRESSLER Corp
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SWINDELL DRESSLER CORP
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27FURNACES; KILNS; OVENS; RETORTS
    • F27BFURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/06Furnaces 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
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27FURNACES; KILNS; OVENS; RETORTS
    • F27BFURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/02Furnaces 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
    • F27B9/021Furnaces 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 having two or more parallel tracks
    • F27B9/022With two tracks moving in opposite directions
    • F27B9/023With two tracks moving in opposite directions with a U turn at one end
    • F27B9/024With two tracks moving in opposite directions with a U turn at one end with superimposed tracks
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27FURNACES; KILNS; OVENS; RETORTS
    • F27BFURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/14Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment
    • F27B9/20Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path tunnel furnace
    • F27B9/26Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path tunnel furnace on or in trucks, sleds, or containers

Definitions

  • the present invention relates to continuous tunnel kilns of a known double deck type, in which the goods treated are inserted in the kiln chamber at one end and are moved through the kiln at one level, and are then moved back through the kiln chamber at a different level.
  • the above mentioned kiln end may be referred to as the goods receiving and discharge end, and the opposite end may be referred to as the level shift end of the kiln.
  • such 'a kiln is heated by heating elements, which may be electric resistors or combustion chambers of known form, and which are located only in the portion of the kiln adjacent its level shift end,.the incoming goods being preheated in the remainder of the kiln, by heat transferred to them from the outgoing goods, which are thereby cooled.
  • heating elements which may be electric resistors or combustion chambers of known form, and which are located only in the portion of the kiln adjacent its level shift end,.the incoming goods being preheated in the remainder of the kiln, by heat transferred to them from the outgoing goods, which are thereby cooled.
  • the highest kiln temperatures are attained in such a kiln at, or adjacent, its level shift end.
  • While the goods may be moved through such a kiln in various ways, it is generally essential that mechanism should be provided at the level shift end of the kiln, to transfer bodies, which in some cases may be ingots or otherparts subjected to heat treatment in the kiln but usually are supports for the goods treated in the form of kiln cars, boxes, or trays, successively approaching the level shift end of the kiln chamber, from the approach level to the return level, and the primary object of the present invention is to provide simple and effective mechanism Within the kiln chamber for transferring goods supports or other bodies from one of said levels to the other.
  • a preferred form of the present invention hereinafter described in detail, was devised for use in a kiln, m which goods supporting trays or boxes are moved in a known manner through the kiln chamber in eachdirection on a corresponding set of conveyor rolls which extend across the kiln chamber at the proper level, and have their ends jouralled in the kiln walls.
  • conveyor rolls are not idle rolls over which the work is pushed or pulled, but are rotated to advance the work supports, as by means of a sprocket chain or reciprocating pawls, respectively engaging sprocket wheels orratchet wheels carried by the rolls.
  • My improved goods level shifting mechanism is characterized by its simple and effective construction and operation, and by its adaptability for use under relatively high temperatures, which in some cases, are but little below that at which mechanism parts made of any metal'practically available for use in the construction of the level shiftingmechanism will fail.
  • said mechanism comprises a transfer table or platform having a plurality of free running, or idler, rolls, and table supporting and operating means comprising arms each so pivoted at one end to the table and at its opposite end to turn about a stationary axis extending transversely of the kiln, that said arms form a parallel motion linkage for holding the table horizontal while swinging it back and forth between one position in which its rolls are at the level of the upper set of conveyor rolls, and a second level in which the table rolls are at a level of the lower set of conveyor rolls.
  • Another main object of the invention is to provide improved means for moving the goods off the transfer table and on to the return set of conveyor rolls.
  • a further important object of the invention is to provide 'simple and effective means for automatically effecting the intermittent movements of the table between its different levels, and the intermittent operation of the means for moving the goods or wares from the table onto the return conveyor rolls, and suitably relating said movements and operations to one another and to the movements of the goods supports longitudinally of the kiln.
  • Fig. 1 is a diagrammatic side elevation of a continuous tunnel kiln, partly broken away and in section;
  • Fig. 2 is a transverse section on the line 22 of Fig. 3;
  • Fig. 3 is an elevation of a level shift end portion of the kiln, in section on the line 33 of Fig. 2;
  • Fig. 4 is a side elevation illustrating a detail of construction
  • Fig. 5 is a diagram illustrating an automatic control system for the motors operating transfer table and the means for moving goods off the a table.
  • the set of lower rolls 1) similarly extends out of the kiln chamber at its goods receiving and discharging end, into end to end relation with a receiving table or platform comprising rolls D onto which the rolls b discharge the boxes or trays C.
  • the platform rolls D are not driven but are free to turn as the work supports C are moved onto the rolls D by the conveyor rolls b, and are moved on? the rolls D by an attendant removing goods from the kiln.
  • the upper and lower sets of conveyor rolls B and b do not extend to the level shift end of the kiln chamber, but terminate at greater and lesser distances, respectively, therefrom, to permit the transfer table E to be positioned as hereinafter described.
  • the transfer table E is adapted to receive trays C, one at a time from the conveyor rolls and comprises a rigid grid like frame nearly as wide as the kiln chamber and slightly shorter than a goods support C, and comprises side bar portions connected by transverse bars e.
  • the table E is movable between an uppertray receiving and lower tray delivering position at the levels of the rolls B and b, respectively, which are shown in Fig. 3, in full and dotted lines, respectively.
  • the table E comprises free running rolls E, which are parallel to the conveyor rolls B and b and are journalled at their ends in the table frame, and which are suitably displaced from one another longitudinally of the kiln, to properly support a tray or box C not only during the level shifting operation, but also when a tray or box is being moved on to and off of the table.
  • the table E is supported, and given its movements, by a pair of arms E and a second pair of arms E
  • the two arms E are located at opposite sides of the kiln chamber and each is secured at one end to a corresponding rock shaft E extending through the adjacent side wall of the kiln.
  • the end of each arm E remote from the corresponding shaft E is pivotall connected to the frame of the table E adjacent the end of the latter which is nearest to the level shift end of the kiln.
  • the two arms E one at each side of the kiln chamber are each mounted at one end on a corresponding shaft E extending through the adjacent side wall of the kiln chamber so as to turn about the axis of said shaft, and each is pivotally connected to the frame of the table E adjacent the end of the latter which is nearest to the goods receiving and discharge end of the kiln chamber.
  • a go s suppor g When the table E is in its lower position, a go s suppor g, then on the table, may be pushed off the t le and on to the rolls 2), by a ram or pusher bar which extends longitudinally of the kiln thro gh the end wall of the kiln chamber, and has itsouter end connected to a cross head I mounted in a guideway I for movement in the longitudinal direction of the ram and kiln.
  • the means shown for giving the ram I its longitudinal movements include a lever J having its lower end journalled on a stationary fulcrum pivot J.
  • the lever J is oscillated to advance and retract the arm by means of a crank shaft K parallel to and above the pivot J, and carrying a crank arm K pivotally connected at its free end to a cross head K working in a longitudinal slot or guideway J in the lever J.
  • the crank shaft K as shown forms the output or driven shaft of a speed reducing gear K which is driven by an intermittently operating motor L.
  • the motor M is set into operation to lower the table.
  • Such operation of the motor M is interrupted when the table reaches its lowermost dotted line position, and the motor L is then operated to effect one complete rotation of the crank shaft K, and thereby move the lever J from the full line position into the dotted line position, and thence back into full line position shown in Fig. 3.
  • the plunger I is advanced sufficiently to push a goods support C, initially on the table E, off the latter, and on to the rolls 2). After the plunger readiness to receive the goods support C then at I the head of the train of such supports being advanced by the rolls B.
  • the motor M is energized for operation in the direction to lower the table E by the movement of a switch Q into engagement with a switch contact q, whereby a motor'energizing circuit including a field winding M is operatively connected to supply electric conductors I and 2.
  • the motor M is energized for operation in the reverse direction by the movement of a switch R into engagement with a contact r, whereupon a second motor energizing circuit including a field winding M is operatively connected to the supply conductors I and 2.
  • a motor'energizing circuit including a field winding M is operatively connected to supply electric conductors I and 2.
  • the motor L is energized for operation in the one direction in which that motor operates, by the adjustment of a switch S into engagement with a contact s, whereby an energizing circuit for the motor L including its field winding L is operatively connected between the supply conductors l and 2.
  • each of the switches Q, R and S is moved into its motor energizing position by electromagnetic means comprising coils t, 1m and w, respectively.
  • each of the switches Q and R is moved out of its motor energizing position by mechanical means comprising a cam rotated on and in accordance with changes in the position of the table E, or, as diagrammatically shown, in direct accordance with the corresponding movements of the motor M.
  • the switch 5' is moved to deenergizethe'motor L, by electromagnetic means including a coil m.
  • each of the switches Q,-R and S, and also the switch W provided for sequence control purposes hereafter set forth is unbiased and tends to remain in any position into which it is adjusted until positively moved into a different position.
  • a bridging contact U mechanically connected to the rock shaft P is moved into bridging relation with a pairof contacts T when the arm P is moved by a work support into its fullline position shown in Fig. 3.
  • the contacts T are thus connected, theycomplete an energizing circuit connection between the conductors l and 2 for the coil t, the energization of which moves the switchQ into engagement with the switch contact q, and thereby starts the motor M into operation in the direction to lower the table E.
  • the energizing circuit forthe coil It also includes a switch actuating coil ta, and apair of contacts rf which are connected by a bridging contact ra carried by the switch R, when the circuit is energized as above described.
  • the contacts r are not connected by the bridging contact m, and the coil t is not energized by movement of the contact U into bridging relation with the contacts T, during the subsequent table elevating operation, as the switch R then holds its contact ra out of engagement with the contacts r.
  • the latter moves the switch W into the position shown in Fig. 5, in which it forms a bridge connecting contact wa.
  • the bridging of the contacts wo has no immediate result, but is a control circuit preparing action, essential to the energization of the motor L which occurs when the continuing operation of the motor M operates the cam M to shift the switch Q from the position shown in Fig. into its other operative position, in which an insulated contact part qa, carried by the switch, forms a bridging connection between contacts q.
  • the bridging of the contacts q closes a control circuit connection between supplyconductors I' and2, whichincludes the contacts wa, the contacts q, and the coil 10.
  • the contact Y In its initial and final position shown in Fig. 5, the contact Y forms a bridging connection between two contacts X. In some intermediate portion of its turning movement, the contact Y forms a bridging connection between two contacts Z, and thereby momentarily energizes a control circuit connection between sup-ply conductors l and 2 which includes a coil 2 thereby energized to shift the switch W out of engagement with the contacts um and into bridging engagement with contacts wb, and thereby prepare a control circuit for energization. on the subsequent return of the contact Y into position shown in Fig. 5.
  • the last mentioned control circuit r includes switch actuating coils :c and 02a.
  • the'operative and return movements of the lever J may be effected in a desirably short period of time, without accelerating or decelerating the movement of the work support operated on, rapidly enough to subject the work to a significant jar or shock, when the work support is initially engaged by the ram, or in the event that the work support engaged by the ram is moved by the latter into engagement with the rear goods support of the train of goods supports moving to the goods receiving and discharge end of the kiln.
  • each of the four rolls b closest to the level shift end of the kiln may have its driving wheel N journalled on the roll and be arranged to drive the latter, as shown in Fig. 4, through pawls N carried by the wheel M and engaging a ratchet wheel N secured to the roll.
  • Each of the four overrunning rolls provided with parts N, N and N is thus free to revolve with an angular velocity greater than that of the driving wheel N mounted on it.
  • the axes of the pivotal connections between the table and the links E and E are slightly to the rear of the axes of the shafts E and E respectively.
  • the initial portion of the normal movement of the table E away from its upper position includes a small vertical upwardly directed component. This is not only adapted to nullify any possible tendency of the support '0 on the table E to adhere to and drag forward the support C immediately to its rear, but also tends to eliminate risk of having the table E moved out of its normal full line position as a result of frictional resistance to movement over the table of a support C which is being moved onto the table by the. rolls B.
  • the present invention is not concerned with the form or character of the kiln heating means employed.
  • an advantage characteristic of the invention isthat it does not interfere with the use of any form of heating means customarily employed in heating kilns of the character shown.
  • the kiln is heated by means of a plurality of heating elements 0', each in the form of a tubular combustion chamber of known type.
  • elements 0 are distributed beneath the conveyorrolls b along a portion of the kiln extending away from its level shift and for a distance which may be forty per cent, or so, of the length of the kiln, and other elements 0 are distributed along a portion of the kiln above the pathway for the goods on the rolls B adjacent the level shift end of the kiln and shorter than the portion including the lower elements 0.
  • the vertical depth of the kiln chamber is greater in the portion thereof including the heating elements 0, in the remainder of the kiln.
  • the character of the transfer table E and its operating mechanism is not only such as to avoid interference with the convection current circulation of the kiln atmosphere, which is especially important in a kiln of the type shown, but is such that when the table is in its lower position, desirable access to the portion of the goods pathway above the rolls b, as well as to the portion above the rolls B, is made possible by providing a normally closed, but easily opened, doorway A, in the level shift end wall of the kiln.
  • Such access to the high temperature end portion of the kiln is especially important because of the accidental jamming of goods supports and other accidents, which may occur from time to time in that portion of the kiln.
  • an automatic control system which ineludes means responsive to and operative on the movement of a carrier C into a predetermined position on the table E to start the motor M into operation in the direction to lower the table E, and includes means for stopping the motor M and starting the motor L on the movement of the table E into its lower position, and includes means automatically actuated on the movement of the table E into its lowermost position, to stop the motor M and start the motor L, and includes means automatically actuated on the completion of one revolution of the crank shaft K to interrupt the operation of the motor L and to start the motor M into operation in the direction to move the table E back into its upper position, and includes means automatically actuated on the movement of the table E into its upper position to interrupt the operation of the motor M.
  • the described control system may take various forms, one of which is diagrammatically illustrated by way of example in Fig. 5, and includes means shown in Figs. 2 and 3, which is responsive to the movement of a carrier C into a predetermined position on to the table E.
  • the last mentioned means includes a rock shaft P extending across the kiln structure below the level of the bottom of the table E, when the latter is in its lowermost position.
  • the shaft 1? has secured to it an arm P within the kiln chamber, and a .setof conveyor rolls extending across the kiln chamber atintervals along the lengthof the latclaim as new and desire tosecure byLetters Patent, is:
  • a double deck'continuous tunnel kiln comprising in combination, an elongated kiln chamber, and means for moving goods through the kiln chamber from oneend thereof to the other and thence back to the first mentioned end of the kiln chamber, comprising upper and lower trackways along one of which goods are moved in one direction and along the other of which the goods are moved in the return direction, said lower trackway extending past said upper trackway at said other end of the kiln, a transfer table,
  • a kiln as specified in claim 1 comprising means, separate from the means for moving goods through the kiln along said trackwavs, and adapted to move the goods off the transfer table and on to the trackway along which the goods are moved back to the end of the kiln remote from the table.
  • each trackway is formed by conveyor rolls extending across the kiln chamber and distributed longitudinally thereof, and in which the transfer table comprises free running rolls extending transversely of the kiln chamber and having their upper edges at the same level as the upper edges of the upper trackway conveyor rolls or the lower trackway conveyor rolls, accordingly as the table is in its upper or lower position.
  • each goods trackway comprises a ter, and in which the return trackway conveyor ,rolls immediately, adjacentthe transfer table are adapted to turn ;freely in the direction in which goodsbeing moved off the transfer table tend to turn. the iastmentioned conveyor rolls, and
  • a double deck continuous tunnel kiln comprising in combination, an elongated kiln chamber, and means for moving goods through the kiln chamber from one end thereof to the other and thence back to the first mentioned end of the kiln chamber, comprising a lower trackway along which the goods are moved in one direction and an upper trackway along which the goods are moved in the return direction, said lower trackway extending past said upper trackway at said other end of the kiln and a transfer table, and parallel motion table supporting means comprising arms pivoted to turn about stationary horizontal axes extending transversely to and displaced from one another longitudinally of the kiln and connected to said table to turn relatively thereto about similarly displaced horizontal axes from one another, and adapted to swing said table between an upper position in which the table forms an extension of the upper'track- Way and a lower position in which it forms an extension of the lower trackway.
  • a double deck continuous tunnel kiln comprising in combination, an elongated kiln chamber, a goods trackway in said chamber extending from one end thereof into proximityvwith the other chamber end but separated from the latter by a relatively short distance, a second goods trackway at a level above that of the first men tioned trackway extending along said kiln chamber from said one end thereof into proximity with the other chamber end but separated from the latter by a distance somewhat greater than the first mentioned distance, a transfer table in said kiln chamber, and means for swinging said table between an upper position in which it forms an extension of the upper trackway and a lower position in which it forms an extension of the lower trackway.
  • a tunnel kiln as specified in claim 8 in which said kiln is formed at its end at which the transfer table is locatedwith an end wall formed with a normally closed doorway adapted to be opened to provide access to the kiln chamber.
  • a kiln as specified in claim 1, in which the means for moving the transfer table between its upper and lower positions comprises a horizontal rock shaft extending transversely of the kiln chamber and having arms secured to it at opposite sides of the chamber and each pivotally connected at its free end to said table, and other arms, each pivoted to turnabout a corresponding axis parallel to and at the same'level as said rock shaft, but displaced from the latter in the direction of the length of the kiln and each connected to the table by a pivotal connection at the same level as the pivotal connections between the first mentioned arms and the table and displaced therefrom in the same direction and to the same extent as the said corresponding axis is displaced from said rock shaft.
  • a kiln as specified in claim 1 inwhich goods are moved along the upper and lower 'trackways respectively toward and away from the end of the kiln at which the transfer table is located ,and in which an arm pivoted to turn about an axis transverse to the kiln and adjacent the 10 lower trackway level, extends between the table and the adjacent end of the'kiln in position to be engaged and given a movement away from the table by goods moved on to the table from the last mentioned trackway, and including power mechanism for moving the table from its upper position to its lower position set into operation by the said movement of said arm away from the table.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Tunnel Furnaces (AREA)

Description

Dec. 17, 1940.
F. W. BROOKE DOUBLE DECK CONTINUOUS KILN Filed Feb. '28, 1959 3 Sheets-Sheet l BY q E. if
ATTORNEY Dec. 17, 194-0. F. w. BROOKE 2.2249
DOUBLE DECK CONTINUOUS KILN Filed Feb. 28, 1959 3 Sheets-Sheet 5 F rt ORNEY ATT Patented Dec. 17, 1940 PATENT OFFICE DOUBLE DECK CONTINUOUS KILN Frank W. Brooke, Pittsburgh, Pa., assignor to Swindell-Dressler Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Application February 28, 1939, Serial No. 258,893
12 Claims.
The present invention relates to continuous tunnel kilns of a known double deck type, in which the goods treated are inserted in the kiln chamber at one end and are moved through the kiln at one level, and are then moved back through the kiln chamber at a different level. For identification purposes, the above mentioned kiln end may be referred to as the goods receiving and discharge end, and the opposite end may be referred to as the level shift end of the kiln.
Ordinarily, such 'a kiln is heated by heating elements, which may be electric resistors or combustion chambers of known form, and which are located only in the portion of the kiln adjacent its level shift end,.the incoming goods being preheated in the remainder of the kiln, by heat transferred to them from the outgoing goods, which are thereby cooled. In consequence, the highest kiln temperatures are attained in such a kiln at, or adjacent, its level shift end.
While the goods may be moved through such a kiln in various ways, it is generally essential that mechanism should be provided at the level shift end of the kiln, to transfer bodies, which in some cases may be ingots or otherparts subjected to heat treatment in the kiln but usually are supports for the goods treated in the form of kiln cars, boxes, or trays, successively approaching the level shift end of the kiln chamber, from the approach level to the return level, and the primary object of the present invention is to provide simple and effective mechanism Within the kiln chamber for transferring goods supports or other bodies from one of said levels to the other.
A preferred form of the present invention, hereinafter described in detail, was devised for use in a kiln, m which goods supporting trays or boxes are moved in a known manner through the kiln chamber in eachdirection on a corresponding set of conveyor rolls which extend across the kiln chamber at the proper level, and have their ends jouralled in the kiln walls. Ordinarily, such conveyor rolls are not idle rolls over which the work is pushed or pulled, but are rotated to advance the work supports, as by means of a sprocket chain or reciprocating pawls, respectively engaging sprocket wheels orratchet wheels carried by the rolls.
My improved goods level shifting mechanism is characterized by its simple and effective construction and operation, and by its adaptability for use under relatively high temperatures, which in some cases, are but little below that at which mechanism parts made of any metal'practically available for use in the construction of the level shiftingmechanism will fail. In its preferred form said mechanism comprises a transfer table or platform having a plurality of free running, or idler, rolls, and table supporting and operating means comprising arms each so pivoted at one end to the table and at its opposite end to turn about a stationary axis extending transversely of the kiln, that said arms form a parallel motion linkage for holding the table horizontal while swinging it back and forth between one position in which its rolls are at the level of the upper set of conveyor rolls, and a second level in which the table rolls are at a level of the lower set of conveyor rolls.
Another main object of the invention is to provide improved means for moving the goods off the transfer table and on to the return set of conveyor rolls.
A further important object of the invention is to provide 'simple and effective means for automatically effecting the intermittent movements of the table between its different levels, and the intermittent operation of the means for moving the goods or wares from the table onto the return conveyor rolls, and suitably relating said movements and operations to one another and to the movements of the goods supports longitudinally of the kiln.
The various features of novelty which characterize my invention are pointed out with particularity in the claims'annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages, and specific objects attained with its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of the invention.
Of the drawings:
Fig. 1 is a diagrammatic side elevation of a continuous tunnel kiln, partly broken away and in section;
Fig. 2 is a transverse section on the line 22 of Fig. 3;
Fig. 3 is an elevation of a level shift end portion of the kiln, in section on the line 33 of Fig. 2;
Fig. 4 is a side elevation illustrating a detail of construction; and
Fig. 5 is a diagram illustrating an automatic control system for the motors operating transfer table and the means for moving goods off the a table.
In the drawings, I have illustrated the use of my invention in a kiln A in which goods are moved through the kilnchamber from the goods receiving and discharging end of the chamber on an upper set of conveyor rolls B, and are then moved back from the level shift end of the kiln on a lower set of conveyor rolls b. The rolls of each set extend transversely to the kiln chamber, and have their ends journalled at the opposite sides of the chamber. As shown the rolls B and b are each formed with two tray guiding flanges, B and b, respectively, one adjacent each side wall of the kiln chamber, and spaced apart by a distance equal to the width of trays or boxes C, which support the goods moved through the kiln.
As shown in Fig. 1, the upper set of rolls B,
extends out of the kiln chamber at its goods receiving and discharging end, to provide a convenient loading platform on which the trays or boxes C may readily be placed in proper spaced relation. As shown, the set of lower rolls 1) similarly extends out of the kiln chamber at its goods receiving and discharging end, into end to end relation with a receiving table or platform comprising rolls D onto which the rolls b discharge the boxes or trays C. The platform rolls D are not driven but are free to turn as the work supports C are moved onto the rolls D by the conveyor rolls b, and are moved on? the rolls D by an attendant removing goods from the kiln. The upper and lower sets of conveyor rolls B and b do not extend to the level shift end of the kiln chamber, but terminate at greater and lesser distances, respectively, therefrom, to permit the transfer table E to be positioned as hereinafter described.
The transfer table E is adapted to receive trays C, one at a time from the conveyor rolls and comprises a rigid grid like frame nearly as wide as the kiln chamber and slightly shorter than a goods support C, and comprises side bar portions connected by transverse bars e. The table E is movable between an uppertray receiving and lower tray delivering position at the levels of the rolls B and b, respectively, which are shown in Fig. 3, in full and dotted lines, respectively. The table E comprises free running rolls E, which are parallel to the conveyor rolls B and b and are journalled at their ends in the table frame, and which are suitably displaced from one another longitudinally of the kiln, to properly support a tray or box C not only during the level shifting operation, but also when a tray or box is being moved on to and off of the table.
The table E is supported, and given its movements, by a pair of arms E and a second pair of arms E The two arms E are located at opposite sides of the kiln chamber and each is secured at one end to a corresponding rock shaft E extending through the adjacent side wall of the kiln. The end of each arm E remote from the corresponding shaft E is pivotall connected to the frame of the table E adjacent the end of the latter which is nearest to the level shift end of the kiln. The two arms E one at each side of the kiln chamber, are each mounted at one end on a corresponding shaft E extending through the adjacent side wall of the kiln chamber so as to turn about the axis of said shaft, and each is pivotally connected to the frame of the table E adjacent the end of the latter which is nearest to the goods receiving and discharge end of the kiln chamber. The distance between the axis of its pivotal connection with the table and the axis of the shaft E or E on which it is mounted. is the same for each of the arms E and E Those axes are so related moreover, that rotative movements imparted to the crank shafts E external end of each of the shafts E and in mesh with a spur gear F secured to the corresponding end of a horizontal shaft F which extends through the kiln structure at a level below that of the rolls b. As shown, the spur gear F" at one side of the kiln is in mesh with the driving element G of a speed reducing gear G, which has its driving shaft coupled to the shaft of a reversible motor M adapted on its rotation alternately in opposite directions to move the table E back and forth between its upper and lower positions shown in full and dotted lines in Fig. 3.
When the table E is in its lower position, a go s suppor g, then on the table, may be pushed off the t le and on to the rolls 2), by a ram or pusher bar which extends longitudinally of the kiln thro gh the end wall of the kiln chamber, and has itsouter end connected to a cross head I mounted in a guideway I for movement in the longitudinal direction of the ram and kiln. The means shown for giving the ram I its longitudinal movements, include a lever J having its lower end journalled on a stationary fulcrum pivot J. The lever J is oscillated to advance and retract the arm by means of a crank shaft K parallel to and above the pivot J, and carrying a crank arm K pivotally connected at its free end to a cross head K working in a longitudinal slot or guideway J in the lever J. The crank shaft K as shown forms the output or driven shaft of a speed reducing gear K which is driven by an intermittently operating motor L.
In the contemplated operation of the apparatus shown in the drawings, as soon as a work support C is moved into a predetermined suitably centered, position on the table E, then in its upper position, the motor M is set into operation to lower the table. Such operation of the motor M is interrupted when the table reaches its lowermost dotted line position, and the motor L is then operated to effect one complete rotation of the crank shaft K, and thereby move the lever J from the full line position into the dotted line position, and thence back into full line position shown in Fig. 3. As the lever J moves from its full line position into its dotted line position, the plunger I is advanced sufficiently to push a goods support C, initially on the table E, off the latter, and on to the rolls 2). After the plunger readiness to receive the goods support C then at I the head of the train of such supports being advanced by the rolls B.
With the lever J and its operating connections arranged as shown, it takes only about half as long to move the lever J from its dotted line position to its full line position as is required for the reverse movement. Furthermore, the ratio of longitudinal movement of the ram I to the angular movement of the crank shaft K, is much smaller during the initial and final portions than during the intermediate portions of the movement of the ram while in operative engagement counterweight? outside of'the kiln-chamber. The shaft P, arm P" and counterweight P are so proportioned and arranged that during all but the final portion of, the movement of a work support C onto the elevated table E, the arm P will be held by the counterweight P in the generally upright position shown in Fig. 3 in dotted lines, at the left of the full line showing of the arm. As a tray which is being moved on to the table E, approaches the end of such movement, it engages thearml? and moves it out of its dotted line position'and into the position shown in Fig. 3. The movement of the arm P into said full line position is utilized to start the series of motor operations which result in the lowering of the table E, the operation of the ram I to transfer the work support on the table from the latter onto the conveyor rolls b, and the return of the table E to its upper position. 1 i
In the control system form illustrated diagrammatically in Fig. 5, the motor M is energized for operation in the direction to lower the table E by the movement of a switch Q into engagement with a switch contact q, whereby a motor'energizing circuit including a field winding M is operatively connected to supply electric conductors I and 2. The motor M is energized for operation in the reverse direction by the movement of a switch R into engagement with a contact r, whereupon a second motor energizing circuit including a field winding M is operatively connected to the supply conductors I and 2. As shown in Fig. 5, the motor L is energized for operation in the one direction in which that motor operates, by the adjustment of a switch S into engagement with a contact s, whereby an energizing circuit for the motor L including its field winding L is operatively connected between the supply conductors l and 2.
As diagrammatically shown in Fig. 5, each of the switches Q, R and S is moved into its motor energizing position by electromagnetic means comprising coils t, 1m and w, respectively. As diagrammatically shown, each of the switches Q and R, is moved out of its motor energizing position by mechanical means comprising a cam rotated on and in accordance with changes in the position of the table E, or, as diagrammatically shown, in direct accordance with the corresponding movements of the motor M. The switch 5' is moved to deenergizethe'motor L, by electromagnetic means including a coil m. For the purposes of-the system diagrammatically illustrated, each of the switches Q,-R and S, and also the switch W provided for sequence control purposes hereafter set forth, is unbiased and tends to remain in any position into which it is adjusted until positively moved into a different position.
As diagrammatically illustrated in Fig. 5, a bridging contact U mechanically connected to the rock shaft P is moved into bridging relation with a pairof contacts T when the arm P is moved by a work support into its fullline position shown in Fig. 3. When the contacts T are thus connected, theycomplete an energizing circuit connection between the conductors l and 2 for the coil t, the energization of which moves the switchQ into engagement with the switch contact q, and thereby starts the motor M into operation in the direction to lower the table E. Y i
The energizing circuit forthe coil It also includes a switch actuating coil ta, and apair of contacts rf which are connected by a bridging contact ra carried by the switch R, when the circuit is energized as above described. The contacts r are not connected by the bridging contact m, and the coil t is not energized by movement of the contact U into bridging relation with the contacts T, during the subsequent table elevating operation, as the switch R then holds its contact ra out of engagement with the contacts r.
On the energization of the coil ta, the latter moves the switch W into the position shown in Fig. 5, in which it forms a bridge connecting contact wa. The bridging of the contacts wo has no immediate result, but is a control circuit preparing action, essential to the energization of the motor L which occurs when the continuing operation of the motor M operates the cam M to shift the switch Q from the position shown in Fig. into its other operative position, in which an insulated contact part qa, carried by the switch, forms a bridging connection between contacts q. The bridging of the contacts q closes a control circuit connection between supplyconductors I' and2, whichincludes the contacts wa, the contacts q, and the coil 10. The latter, when energized, moves the switch S into engagement with the contacts s, and thus starts the motor L into operation which continues until the crank shaft K is given one complete revolution and one complete revolution is thereby given to a bridging contact Y which is shown in Fig. 5 as carried by an arm secured to the shaft K.
In its initial and final position shown in Fig. 5, the contact Y forms a bridging connection between two contacts X. In some intermediate portion of its turning movement, the contact Y forms a bridging connection between two contacts Z, and thereby momentarily energizes a control circuit connection between sup-ply conductors l and 2 which includes a coil 2 thereby energized to shift the switch W out of engagement with the contacts um and into bridging engagement with contacts wb, and thereby prepare a control circuit for energization. on the subsequent return of the contact Y into position shown in Fig. 5. The last mentioned control circuit r includes switch actuating coils :c and 02a.
The energization of the coil as moves the switch S out of engagement with the contact 8, and thereby deenergizes the motor L, and the energization of the coil rm shifts the switch R into engagement with the contact r, and thereby en ergizes the motor M for operation in the direction to raise the table E from its dotted line position into its full line position shown in Fig. 3. As the table moves into its last mentioned position, the cam 1W moves the switch R out of engagement with the contact 1' and thus terminates the series of control actions initiated by the movement of the arm P from its left hand dotted line position into the full line position shown in Fig. 3.
While in'accordance with the provisions of the statutes, I have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit of my invention as set forth in the appended claims and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features. 1
Having now described my invention, what I with the Work. In consequence, the'operative and return movements of the lever J may be effected in a desirably short period of time, without accelerating or decelerating the movement of the work support operated on, rapidly enough to subject the work to a significant jar or shock, when the work support is initially engaged by the ram, or in the event that the work support engaged by the ram is moved by the latter into engagement with the rear goods support of the train of goods supports moving to the goods receiving and discharge end of the kiln.
Ordinarily, however, I prefer to avoid movement of a work support C engaged by the ram 1, into engagement with the adjacent work support on the conveyor rolls b by making the speed at which the rolls 1) advance the work supports slightly, for example, one percent, higher than the speed at which the work supports are advanced by the rolls B. This result may be secured of course, by making the angular speed of the rolls 1) slightly higher than that of the rolls B, when the rolls are all of the same diameter, or, when the rolls are driven at the same angular speeds, as is ordinarily desirable, the rolls b may be made one per cent, or so, larger in diameter than the rolls B.
To prevent the lower set of rolls 1) from offering objectionable frictional resistance to the movement of the supports C off the table E and on to said rolls, such of the. latter, four as shown. as may be engaged by a support C which is being advanced by the ram I, are free to overrun, or turn freely at a velocity greater than that at which they are turned by the normal conveyor roll rotating means. Said rolls may be given their overrunning capacity in various known ways. Thus, for example, each of the four rolls b closest to the level shift end of the kiln, may have its driving wheel N journalled on the roll and be arranged to drive the latter, as shown in Fig. 4, through pawls N carried by the wheel M and engaging a ratchet wheel N secured to the roll. Each of the four overrunning rolls provided with parts N, N and N is thus free to revolve with an angular velocity greater than that of the driving wheel N mounted on it.
Advantageously, and as is shown in Fig. 3, when the table E is in its upper position the axes of the pivotal connections between the table and the links E and E are slightly to the rear of the axes of the shafts E and E respectively. In consequence, the initial portion of the normal movement of the table E away from its upper position includes a small vertical upwardly directed component. This is not only adapted to nullify any possible tendency of the support '0 on the table E to adhere to and drag forward the support C immediately to its rear, but also tends to eliminate risk of having the table E moved out of its normal full line position as a result of frictional resistance to movement over the table of a support C which is being moved onto the table by the. rolls B. With the described arrangement, such tendency to objectionable movement of the table E is opposed by gravitational forces which tend to turn the arms E and E counterclockwise as seen in Fig. 3 from their upper position. As will be apparent, the described arrangement makes it readily possible to provide the side walls of the in with stops positively preventing movement of the table E to the left of its full line position show in Fig. 3.
As previously indicated, the present invention is not concerned with the form or character of the kiln heating means employed. On the contrary, an advantage characteristic of the invention isthat it does not interfere with the use of any form of heating means customarily employed in heating kilns of the character shown. As shown in the drawings, the kiln is heated by means of a plurality of heating elements 0', each in the form of a tubular combustion chamber of known type. As shown, elements 0 are distributed beneath the conveyorrolls b along a portion of the kiln extending away from its level shift and for a distance which may be forty per cent, or so, of the length of the kiln, and other elements 0 are distributed along a portion of the kiln above the pathway for the goods on the rolls B adjacent the level shift end of the kiln and shorter than the portion including the lower elements 0. To provide space for the upper elements 0 and for a desirable convection circulation of the atmosphere in the high temperature portion of the kiln, the vertical depth of the kiln chamber is greater in the portion thereof including the heating elements 0, in the remainder of the kiln. The character of the transfer table E and its operating mechanism is not only such as to avoid interference with the convection current circulation of the kiln atmosphere, which is especially important in a kiln of the type shown, but is such that when the table is in its lower position, desirable access to the portion of the goods pathway above the rolls b, as well as to the portion above the rolls B, is made possible by providing a normally closed, but easily opened, doorway A, in the level shift end wall of the kiln. Such access to the high temperature end portion of the kiln, is especially important because of the accidental jamming of goods supports and other accidents, which may occur from time to time in that portion of the kiln.
To automatically start and stop the motors M and L as required for the previously mentioned normal mode of operation, I have devised an automatic control system, which ineludes means responsive to and operative on the movement of a carrier C into a predetermined position on the table E to start the motor M into operation in the direction to lower the table E, and includes means for stopping the motor M and starting the motor L on the movement of the table E into its lower position, and includes means automatically actuated on the movement of the table E into its lowermost position, to stop the motor M and start the motor L, and includes means automatically actuated on the completion of one revolution of the crank shaft K to interrupt the operation of the motor L and to start the motor M into operation in the direction to move the table E back into its upper position, and includes means automatically actuated on the movement of the table E into its upper position to interrupt the operation of the motor M. v
The described control system may take various forms, one of which is diagrammatically illustrated by way of example in Fig. 5, and includes means shown in Figs. 2 and 3, which is responsive to the movement of a carrier C into a predetermined position on to the table E. The last mentioned means includes a rock shaft P extending across the kiln structure below the level of the bottom of the table E, when the latter is in its lowermost position. The shaft 1? has secured to it an arm P within the kiln chamber, and a .setof conveyor rolls extending across the kiln chamber atintervals along the lengthof the latclaim as new and desire tosecure byLetters Patent, is:
1. A double deck'continuous tunnel kiln, .comprising in combination, an elongated kiln chamber, and means for moving goods through the kiln chamber from oneend thereof to the other and thence back to the first mentioned end of the kiln chamber, comprising upper and lower trackways along one of which goods are moved in one direction and along the other of which the goods are moved in the return direction, said lower trackway extending past said upper trackway at said other end of the kiln, a transfer table,
and means for moving said table in parallelism I with itself alonga path curved about an axis transverse to the length of the kiln chamber between an upper position in which the table forms an extension of the upper trackway and a lower position in which the table forms an extension of the lower trackway.
2. A kiln as specified in claim 1 comprising means, separate from the means for moving goods through the kiln along said trackwavs, and adapted to move the goods off the transfer table and on to the trackway along which the goods are moved back to the end of the kiln remote from the table.
3. A kiln as specified in claim 1, including a power mechanism for moving the transfer table, means actuated by goods moving on to the transfer table, when the latter is in the position in which it forms an extension of the trackway along which goods are moved toward the end of the kiln at which the table is located, to set said mechanism into operation to move the transfer table into the position to which it forms an extension of the trackway on which goods are moved away from the transfer table, power means automatically set into operation on the movement of the table into its last mentioned position, to move goods off the table and on to the last mentioned trackway and means automatically actuated after a predetermined extent of operation of said power means to interrupt the operation of the latter and to set' said mechanism into operation toreturn said table to its goods receiving position.
4. Akiln as specified in claim 1, including means adapted to move goods off the transfer table and on to the trackway along which the goods are moved away from the table, comprising a lever ivoted at one end to oscillate about a stationary axis, a goods engaging device operatively connected to the other end of the lever, a crank arm revolving about an axis parallel to the first mentioned axis and a pivotal connection between the said crank arm and lever slidable along an intermediate portion of the length of the latter and through which said device is moved in the direction to move goods off the table and is moved in the opposite direction during greater and lesser portions, respectively, of each rotation of the crank shaft.
5. A tunnel kiln as specified in claim 1, in which each trackway is formed by conveyor rolls extending across the kiln chamber and distributed longitudinally thereof, and in which the transfer table comprises free running rolls extending transversely of the kiln chamber and having their upper edges at the same level as the upper edges of the upper trackway conveyor rolls or the lower trackway conveyor rolls, accordingly as the table is in its upper or lower position.
6. A continuous tunnel kiln as specified in claim 1, in which each goods trackway comprises a ter, and in which the return trackway conveyor ,rolls immediately, adjacentthe transfer table are adapted to turn ;freely in the direction in which goodsbeing moved off the transfer table tend to turn. the iastmentioned conveyor rolls, and
comprising means for positively rotating the last mentioned rolls and the other rolls of the same set in the direction to move the goods to the end of the kiln chamber remote from the transfer table. r
7. A double deck continuous tunnel kiln,,comprising in combination, an elongated kiln chamber, and means for moving goods through the kiln chamber from one end thereof to the other and thence back to the first mentioned end of the kiln chamber, comprising a lower trackway along which the goods are moved in one direction and an upper trackway along which the goods are moved in the return direction, said lower trackway extending past said upper trackway at said other end of the kiln and a transfer table, and parallel motion table supporting means comprising arms pivoted to turn about stationary horizontal axes extending transversely to and displaced from one another longitudinally of the kiln and connected to said table to turn relatively thereto about similarly displaced horizontal axes from one another, and adapted to swing said table between an upper position in which the table forms an extension of the upper'track- Way and a lower position in which it forms an extension of the lower trackway.
8. A double deck continuous tunnel kiln, comprising in combination, an elongated kiln chamber, a goods trackway in said chamber extending from one end thereof into proximityvwith the other chamber end but separated from the latter by a relatively short distance, a second goods trackway at a level above that of the first men tioned trackway extending along said kiln chamber from said one end thereof into proximity with the other chamber end but separated from the latter by a distance somewhat greater than the first mentioned distance, a transfer table in said kiln chamber, and means for swinging said table between an upper position in which it forms an extension of the upper trackway and a lower position in which it forms an extension of the lower trackway.
9. A tunnel kiln as specified in claim 8 in which said kiln is formed at its end at which the transfer table is locatedwith an end wall formed with a normally closed doorway adapted to be opened to provide access to the kiln chamber. Y
10. A kiln as specified in claim 8, including kiln heating elements adjacent the end of the kilnchamber at which the transfer table is located above the upper and below the lower of the two tr-ackways'.
11. A kiln as specified in claim 1, in which the means for moving the transfer table between its upper and lower positions comprises a horizontal rock shaft extending transversely of the kiln chamber and having arms secured to it at opposite sides of the chamber and each pivotally connected at its free end to said table, and other arms, each pivoted to turnabout a corresponding axis parallel to and at the same'level as said rock shaft, but displaced from the latter in the direction of the length of the kiln and each connected to the table by a pivotal connection at the same level as the pivotal connections between the first mentioned arms and the table and displaced therefrom in the same direction and to the same extent as the said corresponding axis is displaced from said rock shaft.
12. A kiln as specified in claim 1 inwhich goods are moved along the upper and lower 'trackways respectively toward and away from the end of the kiln at which the transfer table is located ,and in which an arm pivoted to turn about an axis transverse to the kiln and adjacent the 10 lower trackway level, extends between the table and the adjacent end of the'kiln in position to be engaged and given a movement away from the table by goods moved on to the table from the last mentioned trackway, and including power mechanism for moving the table from its upper position to its lower position set into operation by the said movement of said arm away from the table.
FRANK W. BROOKE.
US258893A 1939-02-28 1939-02-28 Double deck continuous kiln Expired - Lifetime US2224895A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2826314A (en) * 1953-10-28 1958-03-11 Norton Co Tunnel kiln loading and discharging mechanism
FR2442416A1 (en) * 1978-11-23 1980-06-20 Welko Ind Spa ROLLER OVEN COMPRISING A DRYING CHANNEL IN PARTICULAR FOR CERAMIC OR REFRACTORY MATERIALS
US4229878A (en) * 1978-11-30 1980-10-28 Chugairo Kogyo Kaisha Ltd. Method of operating a reheating furnace in a hot rolling line and a reheating furnace employed therefor

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2826314A (en) * 1953-10-28 1958-03-11 Norton Co Tunnel kiln loading and discharging mechanism
FR2442416A1 (en) * 1978-11-23 1980-06-20 Welko Ind Spa ROLLER OVEN COMPRISING A DRYING CHANNEL IN PARTICULAR FOR CERAMIC OR REFRACTORY MATERIALS
US4229878A (en) * 1978-11-30 1980-10-28 Chugairo Kogyo Kaisha Ltd. Method of operating a reheating furnace in a hot rolling line and a reheating furnace employed therefor

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