US3464573A

US3464573A - Metal charging of a melting chamber

Info

Publication number: US3464573A
Application number: US610621A
Authority: US
Inventors: Joseph R Riley
Original assignee: CM Kemp Manufacturing Co
Current assignee: Cm Kemp Manufacturing Co; CM Kemp Manufacturing Co
Priority date: 1967-01-20
Filing date: 1967-01-20
Publication date: 1969-09-02
Anticipated expiration: 1986-09-02

Description

p 2, 1959 J. R. RILEY 3,464,573

METAL CHARGING OF A MELTING CHAMBER Filed Jan. 20, 1967 2 Sheets-Sheet l [ATTORNEYS J. R. RILEY Sept. 2, 1969 METAL CHARGING OF A MELTING CHAMBER 2 Sheets-Sheet 2 Filed Jan. 20, 1967 nIA-z'. r \J-Ml. IIO|I+ Q T .L. z w ,1 g 4 5 w m 6% w Kw! i u 0, i F HEP Q E 0 8 2 2 a United States Patent 9 METAL CHARGING OF A MELTING CHAMBER Joseph R. Riley, Catonsville, Md., assignor to The C. M.

Kemp Manufacturing Company, Glen Burnie, Md., a

corporation of Maryland Filed Jan. 20, 1967, Ser. No. 610,621 Int. Cl. B65g 11/00 US. Cl. 214-35 14 Claims ABSTRACT OF THE DISCLOSURE A device for charging pieces of metal into the molten metal of a melting chamber, the device having a rotatable chute for turning the metal pieces as they slide on it to effect their edge-entry into the molten metal.

This invention provides for a device for charging metal pieces into a melting chamber or furnace by edge-entering the pieces into the molten metal in the chamber so that they are quickly and efiiciency melted without causing harmful splashing on the wall of the chamber.

The device has a particular use in the printing industry where semi-cylindrical stereotype metal plates are returned from a printing press after use to a remelt chamber so that they can be melted down to supply molten metal for stereotype plate casting machines. Heretofore, the plates were returned manually to the remelt chamber or by means of a conveyor and then charged into the chamber by means of a gravity chute. The plates being heavy and cumbersome due to their cylindrical shape and weight cause, when charged into the molten metal, splashing of metal so as to foul the interior of the remelt chamber with splashings of the metal which when solidified hampers the remelt operation and requires expensive cleaning of the chamber. Also, chute charging has involved delays due to insufficient chute discharge capacity resulting in back-up and jamming of plates on the chute requiring the time and expense of manual effort to defiect them into the molten metal.

This invention overcomes the disadvantages set forth above by contemplating rapid charging or feeding of metal pieces into a melting chamber or furnace having a molten metal bath therein in a controlled and uniform manner so that the pieces can pass quickly and continuously into the molten metal by edge-entry so as to significantly reduce the delay caused by back-up and jamming of metal pieces on the chute and the splashing of molten metal which heretofore occurred when metal pieces were charged in a random, uncontrolled manner.

In the case of remelting used stereotype plates, with high frequency return of plates to the remelt chamber such as when a continuous line of them is present on the chute, this invention enables a plurality of plates to enter the molten metal by edge-entry so that a plate is quickly and etficiently melted and any back-up is prohibited by the turning of the chute which drops off any plates backing up into the molten metal so that the plates following will be permitted to edge-enter the molten metal in the normal manner to keep the remelt process in a continuous operation. In this way, the plates are immersed for melting immediately, clearing the chute for following plates to enter.

The rotating chute or slide of the device of this invention is adapted to provide a substantially continuously controlled path and gravity-impelled movement along the chute length so the metal charge pieces or plates are turned as they slide down the chute so that they enter the molten metal in the chamber substantially edge first, thereby producing a smooth and controlled melting of the pieces. Advantageously, this chute can be constructed as a sealed, hollow, cylindrical shell supported to pivot about an axis and inclined so that, in use, its upper end is maintained at a high level out of the molten metal to receive the metal charge pieces, and the exit end floats in the molten metal thus providing for continuous, guided support of pieces passing along its length up to the point of edge-entry. Thus there is provided a self-adjustable chute which rises and falls with the changes in level of the molten metal in the chamber either as it is being charged and/or metal is being removed from it.

Advantageously, the chute can be provided with equally spaced, longitudinally arranged fins around its circumference which support the metal charge pieces, and by reducing surface contact with the chute, speeds chargepiece movement as they slide on the fins and in addition provide control for guiding the pieces in their path of movement down the chute and help in the turning of the pieces with the chute as they slide towards the molten metal surface. It will be appreciated that the fins also provide some degree of surface movement of the molten metal at the area of entry of the pieces, thereby helping to prevent concentrations of dross around the entry of the pieces into the molten metal, and serving also to disperse the plates after discharge further moving them from the path of entry of following plates.

The chute may be associated with an entry tray for guiding stereotype plates or metal feed pieces into proper position for entering onto the chute. It will be appreciated that the speed of rotation of the chute can also be regulated so as to control the angle of entry of the edge of the piece of metal to be melted so that back-up of pieces on the chute is prevented thus providing for melting of charge-pieces in a manner heretofore unavailable to the art. Also, a conveyor system may be provided for transporting metal pieces of the device so that a continuous process of charging the melting chamber can be carried out by conveying the pieces either from their use station in the case of remelt, or from a metal feed supply when charging a furnace so that the charge-pieces enter a tray which guides the pieces onto the chute so they can pass into the molten metal.

Other objects and advantages of this invention will become apparent when taken in light of the description, drawings and claims in which:

FIGURE 1 is a view in elevation showing the rotary chute of my invention positioned for use in a melting chamber and in broken lines the conveyor apparatus and typical positions of stereotype plates on the chute;

FIGURE 2 is a composite view in elevation taken along lines 2.A2A, 2B-2B, and 2C2C of the positions of the plates indicated in FIGURE 1;

FIGURE 3 is a plan view of the rotary chute apparatus in horizontal position and its assocated feed entry tray and drive means;

FIGURE 4 is a view in elevation of the apparatus taken along line 44 of FIGURE 3 showing a stereotype plate positioned in the feed entry tray; and

FIGURE 5 is a section view in elevation taken along line 55 of FIGURE 3.

Referring to the drawings, numeral 20 designates the metal charging device, positioned to feed stereotype plates 22 from a conveyor apparatus 24 into a remelt or melting chamber 26. This chamber is a typical high volume melting pot having an inner steel crucible 27, for containing the reserve of molten type metal 28, and an outer ceramic casing 30 for retaining heat within the molten type-metal. Heater element 32, which can be electric, gas fired or the like, provides the heat necessary to melt the incoming plates and maintain the melt in its molten state. A transfer pump 34, operated by pump motor 35 through saft 36, can then transfer the metal needed through transfer line 37 to the stereotype plate casting machines (not shown) for make-up into new plates for printing of newspapers and the like.

Conveyor apparatus 24, shown in part, conveys used stereotype plates from the printing press (not shown) by moving conveyor chain 38, which is supported in part by rotary conveyor sprocket 40 whose conveyor shaft 42 is journaled in a supporting housing 44 so that the plates are impelled by gravity and conveyor chain dogs 46 along conveyor rails 48 to the metal charging device, (see FIGURE 1).

Metal charging device 20 has a foot plate 52 bolted for support of the charging device to bracket (or crucible flange) 54 which is attached to the chamber wall structure. A pair of spaced apart

upstanding arms

56, 58 rise vertically from the foot plate and together support a pair of outwardly extending

trunnions

60, 62 journalled in

trunnion bearings

64, 66, which are welded to the

side plates

68, 70, respectively. It will be appreciated that the trunnions provide a pivot about which the chute apparatus can turn (see FIGURES 3 and 4), thus providing for changing the angle of inclination of the charging device with respect to the level of the molten metal in the chamber.

Attached to the

side plates

68, 70 along their upper edges are a pair of oppositely arranged

angles

72, 72a forming an entry tray, each of the angles having one of its legs extending upwardly and the other horizontally when the device is horizontally positioned (non-operating position). When the device is in its angled position that is ready to convey plates into the remelt chamber, the tray for receiving and supporting stereotype plates from the conveyor rails and guiding them properly is then positioned for movement of plates from the conveyor. The

side plates

68, 70 extend rearwardly of the

upstanding arms

56, 58 to support a large channel plate 74 which extends down below the foot plate 52 and supports an outwardly extending base plate 76 which is attached to and extends outwardly from the lower end of the channel plate. The base plate suports gear box 78 which is operatively connected to drive motor 80.

Attached to the upper end of channel plate 74 is a metal tube 84 which extends lengthwise between the

side plates

68, 70 and the upstanding arms and provides an elongated cylindrical bearing surface which supports an outer hollow shaft 86 in trunnion-like fashion for pivotal turning thereabout and providing for the support of the rotary chute 88 at its upper end as well as permitting it to revolve about a longitudinal axis extending through it and the metal tube. Tube 84 has welded to it an annular tube plate 90 to which is bolted a tube sprocket 92 through which the tube is revolvably connected by chute chain 94 forming a part of the drive train or mechanism for rotating the chute. The chute chain is operably engaged about gear sprocket 96, which is turned by gear shaft 100 acting through gearing within gear box 78 so that when power is suppied to the motor through leads 102 from a source not shown, the gear shaft, chute chain and the tube are revolved thus providing rotation of the chute. The speed of revolution of the chute is adjustable by known means not shown, such as by altering the gear ratio, or by varying the power input to the motor or by other known ways.

Encircling tube 84 and attached thereto towards the chute end of the tube are a pair of

annular thrust rings

104 and 106 spaced apart along the outer surface of hollow shaft 86 and which bear against horseshoe-like thrust plate 108 which is bolted to lugs 110 extending inwardly from the side plates, thereby providing a thrust bearing for maintaining the chute securely positioned in the melt chamber by holding the hollow shaft 86 properly positioned on the tube. Grease fittings 112, 112a provide for lubricating the bearing surface between the hollow shaft and tube (see FIGURES 3, 4 and 5).

Chute 88 is formed from a hollow cylindrical shell 114 sealed at its outer extremity by chute end plate 116 and partially cosed at its inner end by

annular ring plates

118 and 120 which are attached to hollow shaft 86 so the chute is firmly supported on the open ended tube 84. It will be appreciated that this construction provides for the interior of the cylinder to be open to the atmosphere through the open end of the tube so that any gases in the cylinder can expand and contract without damage to the cylinder. The chute has four radially positioned fins or vanes 124 weded to the shell along its length which pro vides support for the stereotype plates moving along the chute. Each fin has a notch 126 at its upper inner corner which allows a plate moving onto the chute from the feed entry tray to pass smoothly onto the chute during its rotation.

The rotary chute is supported at its outer or exit end by flotation in the molten type-metal or melt and is pivotally suppored at its plate receiving inner end above the surface of the metal to turn about the axis of the

trunnions

60, 62, so that the outer or melting chamber end of the chute floats in the molten metal regardless of the level of metal in the chamber. An ear 128 is provided with adjustable threaded bolt 130 to form a limit stop which can be adjusted to prevent a low level of metal in the chamber from allowing the outer end of the chute to contact the bottom of the chamber which might cause damage to the chute or its fins. Also, ears 132 and 132a with their associated threaded bolts 134 can be adjusted to contact

abutments

136 and 136a, the ears, bolts, and abutments acting as stops for limiting the upward swing of the chute (see FIGURES l, 4 and 5) as for example, when the chute is raised to horizontal position in order to conduct routine inspection of it.

The following is a typical processing of plates for melting them down to supply a continuous charge to a molten metal chamber for feeding molten metal to a stereotype casting machine to make printing press plates for a printing operation:

In operation the metal charging device is supported so as to be positioned in the melting chamber with the rotary chute inclined in the chamber so that its one end floats on the molten metal and the other end is so positioned as to receive plates from the conveyor apparatus. The chute is so inclined that it provides for rapid sliding of the plates and a degree of turning of them "so that the plates edge-enter the molten metal or if they back up are turned off the chute to fall and edge-enter the molten metal. The chute is rotated by means of a drive mechanism which extends through a drive train powered by a drive motor and gear box. Operatively connected to the gear box is the chute chain which rotates the metal tube 84 about its lonigtudinal axis moving the chute at a preselected speed. The speed of the chute may be in the range of from about 8 r.p.m., to about 15 r.p.m., with about 12 rpm. being a good working speed. Plates returning from the printing press to be melted down are carried by the conveyor apparatus 24 which moves the plates on the conveyor rails 48 towards the charging device. The conveyor rails, which are positioned slightly over and Within the feed entry tray, provide for supporting the plates and guiding them onto the tray. Plates then move from the tray onto the rotating chute by gravity and inertia due to their substantial weight and are guided by the tray as they slide directly onto the chute as shown by the position of the stereotype plate drawn in solid lines in FIGURE 1.

In passing onto the chute, a plate is guided onto at least two of the fins which act as runners and controls plate downward motion with respect to the rotating chute. As the plate slides down the chute on the fins, it turns with the chute so that the plate takes a spiraling course during its travel on the chute and edge-enters the molten metal where it is melted. Thus, as each plate is successively carried to the feed entry tray, it is then propelled by gravity down the chute so that as one plate is substantially melted, another plate edge-enters so as to provide a continuous quick melting of plates with the elimination of splashing of the molten metal and back-up of plates on the chute, since plates backing up on it will fall off due to rotation of the chute which produces a roll-off effect of the backed up plates to help them edgeenter the molten metal.

It will be appreciated that the speed of rotation of the chute may be varied according to the time that is required for a piece of metal to be melted so that another piece can follow it into the molten metal. Also, the angle that the chute makes with respect to the surface of the molten metal can be varied so that the metal piece will be provided with the necessary gravity effect to bring it to its melting position at a speed that will permit edge entry. The angle of inclination of the chute may depend on the size of the metal piece, its weight, the amount of rotation needed to edge-enter the piece into the molten metal, the length of travel on the chute, and the speed which the piece attains as it slides down the chute. Also, the horizontal component of force pressing the piece against the chute and the downward component of force propelling it, can be so regulated as to provide the desired speed and rotation of the pieces so that the proper edge-entry will be provided to eliminate splashing of the molten metal.

Advantageously, it has been found that a chute length of from about 4 feet to about 7 feet, and inclined at an angle of from about 15 to about 35 with respect to the surface of the molten metal and a rotational speed of from about 8 rpm. to about 15 r.p.m. provide an effective combination to produce edge entry of stereotype plates having an average weight of from about 40 .pounds to about 50 pounds.

It will be further appreciated that the metal charging device can have the exit end of the chute floating in the molten metal as described above, or the exit end may be angularly suspended so that the exit end is positioned just above the surface of the molten metal. Where a chute is used in which the exit end is non-floating, the maintaining of the exit end of the chute just above the surface of the metal may be accomplished by a float control mechanism which will control the raising or lowering of the chute so as to maintain the exit end of the chute adjacent to the surface level of the molten metal as it changes due to melting of charge pieces or draw-off of molten metal from the chamber.

It will also be appreciated that while a moving conveyor chain for providing control in conveying the plates to the rotary chute has been described in connection with the invention, it can be advantageous to feed the plates to the chute in a partially controlled or substantially uncontrolled manner as, for example, where the plates are permitted to slide freely on the conveyor rails or are manually fed or delivered into position to enter onto the chute.

While the invention has been described with particularity with reference to a preferred embodiment thereof, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.

What is claimed is:

1. A melting chamber charging device for feeding pieces of charge metal in rapid succession into said chamber comprising a chute adapted to be associated with a melting chamber and inclined therein for continuously charging metal into said chamber, said chute being angularly inclined into said chamber and having means for causing its exit end to float in the surface of the molten metal in said chamber and means operatively connected to said chute for permitting the changing of the angle of said chute with respect to the molten metal as the level of metal in said chamber rises or falls.

2. The charging device of claim 1 in which said chute is provided with means for rotatably turning the chute about its longitudinal axis.

3. The charging device of claim 2 in which said metal feed chute has means for guiding the pieces of metal so that they take a helical path as they travel down the chute.

4. The charging device of claim 2 in which the charging device includes means for uniformly guiding pieces of charge metal onto the inclined chute to assure their edge-entry into the molten metal.

5. The charging device of claim 2 in which the pieces of charge metal are stereotype printing plates.

6. The charging device of claim 1 in which said metal feed chute is cylindrical and is sealed at its exit end to provide a hollow floatable structure.

7. The charging device of claim 6 in which the cylindrical chute has a plurality of spaced longitudinal fins for guiding the pieces of metal as they slide and turn in their travel down the chute.

8. The charging device of claim 2 in which the device has operatively associated with it a conveyor for transporting said metal pieces to it.

9. The charging device of claim 2 in which the feed entry end of said chute is pivoted so that the angle of inclination of said chute can be adjusted in relation to the level of the molten metal when the chute is positioned in said melting chamber.

10. A melting chamber charging device for feeding pieces of charge metal in rapid succession into said chamber comprising a melting chamber having molten metal therein, an inclined chute for continuously charging metal into said chamber, said chute being angularly inclined into said chamber and having means at its exit end for causing said end to float in the surface of said molten metal and means operatively connected to said chute for permitting the changing of the angle of said chute with respect to the level of the molten metal as the level of the metal in said chamber rises or falls.

11. A melting chamber charging device for feeding pieces of charge metal in rapid succession into a molten metal chamber comprising an inclined metal chute, said chute being inclined into said chamber and having its exit end at the surface of the molten metal in said chamber; spaced =fin means positioned on said chute, rotating means operably connected to said chute for turning said fin means about the lengthwise axis of said chute and means for maintaining the exit end of said chute at the surface of the molten metal, whereby pieces of charged metal on said chute are rotated as they slide downwardly on said fins so as to ofiect edge-entry of each piece of metal into said molten metal.

12. The charging device of claim 11 in which said chute is cylindrical.

13. A method for continuously changing uniformly shaped pieces of metal into a variable level melting chamber for supplying metal to a metal casting operation comprising continuously and successively conveying pieces of metal having discrete edge configurations in a uniformly aligned manner onto an inclined chute extending into said melting chamber, sliding each piece of metal in succession down said inclined chute, turning each piece of metal in succession as it slides down said chute to effect a spiraling downward and an edge-entry of each piece of metal into the molten metal in said chamber and automatically varying the angle of the chute by raising or lowering the end of it that extends into the chamber as the level of the molten metal in the chamber is changed by the melting of metal entered into it or by metal drawn from it.

8 14. The method of claim 13 in which the pieces of metal are stereotype plates.

References Cited UNITED STATES PATENTS 1,932,238 10/1933 Winkler 164l41 2,037,554 4/1936 Wagstatf 214-48 2,365,240 12/1944 Arnold 214-17 3,253,723 5/1966 Calderon 2l418 ROBERT G. SHERIDAN, Primary Examiner US. Cl. X.R. 193-3, 17