US3277276A - Electrically heated glue melting device - Google Patents

Description

Oct. 4, 1966 I. G. NICHOL ET'AL 3,277,276

ELECTRICALLY HEATED GLUE MELTING DEVICE I Filed Feb. 17, 1964 5 Sheets-Sheet 1 INVENTORS IVEN G. NICHOL I B ROBERT J. DONQVAN MORGAN FINNEGAN DURHAM 8 PlNE ATTORNEYS 1966 1. G. NICHOL ETAL 3,277,276

' ELEGTRICALLY HEATED GLUE MELTING DEVICE Filed Feb. 17, 1964 5 Sheets-Sheet 2 FlG.-6

INVENTORS IVEN G. NICHOL ROBERT J. DONOVAN BY MORGAN, FINNEGAN, DURHAM 8 PINE ATTORNEYS 1966 1. G. NICHOL. ETAL 3,

ELECTRICALLY HEATED GLUE MELTING DEVICE Filed Feb. 17, 1964 5 Sheets-Sheet 5 ZONE-I ZONE-2. THERMOSTAT THERMOSTAT -O 0 LINE 0 VOLTAGE C 0 G ZONE"| ZONE-2 HEATERS HEATERS INVENTORS IVEN G. NICHOL BY ROBERT J. DONOVAN MORGAN, FINNEGAN, DURHAM 8| PlNE ATTORNEYS United States Patent 3,277,276 ELECTRICALLY HEATED GLUE MELTING DEVICE Iven G. Nichol, Stamford, Conn., and Robert J. Donovan,

Caldwell, N.J., assi'gnors to Morningstar-Paisley, Inc., New York, N.Y., a corporation of New York Filed Feb. 17, 1964, Ser. No. 345,482

1 Claim. (Cl. 219-421) able to applythe glue to the flap portions at elevated temperatures by means of a roller partially immersed in a container of hot glue. As will be seen hereinafter, many problems arise when attempting to heat the glue or. adhesive to the predetermined temperature particularly when it is necessary to replenish the supply of glue.

In the most common type of melter presently available, one set of heaters is provided about a circular shaped container and the solid hot melt heats from the outside and melts toward the center. The center slug is the last to melt down and, as the slug may plug the outlet, it is necessary to wait until the entire mass is molten before the material may be used. Further, addition of fresh, unmelted material in the form of cakes or lumps to the molten mass must be done with extreme caution to avoid splashing the molten material onto the operator. A further disadvantage of adding fresh unmelted material to the molten mass is that it reduces the melt down rate and makes the process of melting a discontinuous operation. Finally, when it is desired to 'increase the melt down rate in such a premelter, overheating often results with deleterious effects on the 'molten product.

It is apparent that the foregoing type of melter would be unsatisfactory for gluing cartons and the like where "it is frequently necessary to replenish the supply of glue.

The device of the present invention has been found "to have particular utility in melting glue or adhesives prior to the 'glue' or adhesive being directed to a second melting pot where the glue is heated to the temperature of application.

For this reason the device of the present invention may hereinafter be referred to as a premelter even though the device of the present invention is not limited to this particular use.

It is therefore an object of this invention to provide a melting device having first and second melting zones for melting adhesives and like material.

A further object of the invention is to provide in a .melting device having first and second melting zones,

means for removing the molten material from the first to the second melting zones immediately upon reaching the molten state.

A further object of the invention is to provide in a melting device having first and second melting zones, a control element between the melting zones for preventing unmelted material from passing from the first melting zone to the second melting zone.

A still further object of the invention is to provide a melting device having, first and second melting zones wherein the heat supplied to each melting zone is independently controlled.

Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be 3,277,276 Patented Oct. 4, 1966 learned by practice of the invention, the objects and advantages being realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

Briefly described, the present invention comprises a container having two separate melting zones, controlled independently of each other. One of the melting zones is in the form of a rectangular channel having an inclined bottom surface to provide for gravitation of melted material into the second melting zone, which holds the molten material under selected temperature by separate heat control. Unmelted material is prevented from entering the second melting zone by means which is pervious tomolten material but impervious to unmelted material. This means comprises a multiple-apertured grate member positioned intermediate the melting zones.

The accompanying drawings, referred to herein and constituting a part thereof, illustrate one embodiment of the invention and, together with the description, serve to explain the principles of the invention.

Of the drawings:

FIGURE 1 is an isometric view illustrating a melting device according to the invention; 1

FIGURE 2 is a longitudinal sectional view taken along lines IIII of FIGURE 1;

FIGURE 3 is a sectional view taken along lines IIIIII of FIGURE 2 illustrating the outlet means of the subject invention;

FIGURE 4 is an enlarged isometric view of the grate means of FIGURE 2;

FIGURE 5 is a sectional view taken of FIGURE 4;

FIGURE 6 is a sectional view taken along lines VIVI of FIGURE 4; and

FIGURE 7 is a schematic wiring diagram of the heating circuits for the melting device illustrating the separate along lines VV thermostatic controls for the heating units.

Referring now to FIGURE 1, there is shown a premelter 10 in accordance with the present invention, the basic container of which is of rectangular channel shape, the upper portion 11 being angularly inclined at approximately 30 to the lower portion 12 to provide an inclined surface 13. The upper end 11 of the channel is provided with a hinged lid 14 (shown in opened position) providing an inlet for admitting fresh unmelted material. Hinged lid 14 also serves as a sealing means to minimize heat loss from the premelter, together with smoke and fumes emitted therein, and also eliminates excessive exposure of the molten material to oxygen, which has deleterious effects on certain materials in the molten form.

At the lower end of the inclined surface 13 means is provided for holding cakes or lumps of the unmelted material in a position on the inclined surface 13. As embodied, this means comprises a grate-like member 15 extending across the width of the inclined surface 13 and affixed to the upper end of the inner wall 24 of the lower portion 12 so as to extend into the channel 18 of upper portion 11. The member 15 (FIGURE 4) comprises a multiplicity of bars 25 and apertures 26 therebetween, the widths thereof to be determined by the particular material it is desired to melt, the only limitation being that the apertures must be of sufficient width to permit the molten material to pass thereth'rough.

A multiplicity of heaters, indicated by reference numeral 16, are located on the bottom wall 17 of the inclined upper portion 11 of the premelter and provide heat for the inclined surface 13. Thus it will be seen that the heated inclined surface, bounded by the grate member and the opening at the upper end thereof, provides a first melting zone for melting down the fresh, unmolten material (hereinafter referred to as Zone 1).

The lower portion 12 of the premelter is substantially vertically oriented and provides a chamber or reservoir 19 for receiving the molten material from channel 18 of upper portion 11. A multiplicity of heaters 20 may be located on each of the four outer walls of the lower portion 12, which provide heat to melt material therein at start-up or to maintain the molten material in a liquid state. Thus, it will be seen that the heated chamber or reservoir 19 provides a second melting zone which either holds molten material in the molten state or will melt down once molten material therein which has become solidified e.g., during shutdown (hereinafter referred to as Zone 2).

The reservoir 19 is provided with an outlet 22 (FIG- URE 3), suitably positioned on any one of the four sides of portion 12 of the premelter, for removing the molten material therefrom for use as may be desired.

It will be understood that the material from which the melting device of the invention is constructed may be of any material compatible with the material to be melted so that there is no sticking or adhering thereto, which is a good heat conductor, and which meets the structural requirements. Through practice, it has been found that aluminum satisfies most of these various requirements.

In accordance with the invention, means is provided for controlling the temperatures of the heaters 16 of Zone 1 independently of the temperatures of the heaters 20 of Zone 2. As embodied, as illustrated in FIGURES 2 and 7, this means comprises two thermostat means, 30, 31, separate and independent from each other, one thermostat 30 conencted to the Zone 1 heaters and the other thermostat 31 connected to the Zone 2 heaters. While it will be understood that the thermostats may be positioned in any appropriate location in each of the heating zones, their preferable location is near the center of each bank of heaters. Also, it is contemplated that conventional thermostats be utilized, and the thermostat probes may be external (as shown) or internal.

With reference to the foregoing description, it is believed the invention will be more fully understood from a typical operation thereof as follows: With the premelter empty, the heaters of both zones are turned on and set to the normal temperature for the Zone 2 heaters. This temperature is determined by the material to be melted and, from practice, it has been found that a temperature of approximately 25 to 50 F. below the temperature at which the molten material is to be used is satisfactory. When the premelter has been heated to the selected temperature, cakes or lumps of unmelted material are inserted into the inclined upper portion (Zone 1) and held against the hot inclined surface by the grate member at the bottom thereof. As the newly added material begins to melt, the molten material flows through the grate and into the heated reservoir (Zone 2) which holds the molten material in the molten state ready for its desired usage.

It will be seen that the two-zone temperature control, coupled with the unique structure of the present invention provides valuable advantages and flexibility in the above operation, not available in previous melting devices. Thus, the inclined surface of Zone 1 permits a higher melt down rate since fresh unmelted material is always added and held in position against a hot surface, rather than being placed directly in a molten mass of ma terial. A further advantage of the inclined surface is that it permits the unmolten material to be fed into the premelter without danger of splash from the hot, molten material.

In addition to the increased melt down rate obtainable from the design of the present invention, the melt down rate may be further increased by increasing the temperature Qf IhQZOIlQl heaters, while maintaining the Zone 2 heaters at the normal pre-selected temperature. This increase in melt down temperature to higher than norm-a1 may be done with only minimal danger of overheating the material since the molten material flows away from the high temperature area as it melts. Of course, the temperature of the Zone 1 heaters should be returned to normal as soon as all the material placed therein has melted; if no fresh material is to be added for a lengthy period, the heaters of Zone 1 may be turned off entirely.

From the foregoing description and typical operation thereof, it will be seen that the premelter of the present invention is capable of a continuous operation not available in other common premelters. In a premelter having only one heating zone, each time fresh material is added, it is often necessary to wait until the entire mass is molten before any of the material may be used, as solid portions may plug the outlet. In the present invention, however, fresh material is not permitted to enter the chamber from which the molten material is withdrawn until it has become completely molten. Therefore, molten material may be withdrawn from the premelter as soon as molten material enters Zone 2 and there is no necessity to discontinue withdrawing the molten material when fresh unmelted material is being added. This combination of features permits a higher usable melt down rate and continuous operation of the premelter.

The invention in its broader aspects is not limited to the specific embodiment herein shown and described but departures may be made therefrom within the scope of the accompanying claim, without departing from the principles of the invention and without sacrificing its chief advantages.

What is claimed is:

A glue melting device, comprising: a hollow, elongated, open-ended, generally tubular channel member positioned on an inclined plane so as to provide said channel member with an upper end and a lower end and a generally flat lower inclined surface, a generally rectangular reservoir extending substantially vertically downwardly from said lower open end of said channel member, said reservoir being open at its upper end, a comb-like member affixed to said upper end of said reservoir and extending transversely thereacross, the teeth of said comb-like member extending upwardly therefrom into said lower endof said channel member, said comb-like member being pervious to melted material but substantially impervious to unmelted material, heating means for heating said lower incline-d surface of said channel member and for further heating said reservoir, said heating means including a plurality of electrical heating units and separate thermostats independently responsive to the temperatureof said channel member and said reservoir for independently regulating the respective heating units, inlet means in said upper end of said channel member for introducing unmelted material thereinto directly onto said lower inclined surface, and outlet means in said reservoir for removing said melted material from said device.

References Cited by the Examiner UNITED STATES PATENTS 1,055,506 3/ 1913 Angebrandt 126-284 1,089,860 3/1914 Nystrom 126-284 1,321,071 11/1919 Hadaway 219-421 2,754,346v 7/1956 Williams 219-422 X 2,809,772 10/ 1957 Weisz 222-146 FOREIGN PATENTS 504,419 8/ 1930 Germany.

ANTHONY BARTIS, Acting Primary Examiner. RICHARD M. WOOD, Examiner.

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