US2420763A - Hot seal cooling mechanism - Google Patents

Description

May 20, 1947. J. D. WELLS HOT SEAL COOLING MECHANISAM Filed Jan.. 2, 1942 I5 Sheets-Sheet l Y INVENTOR JAMES DONAVEN WELLS /ATTORN EY May 20, 1947. J. D. WELLS n HOT SEAL COOLING MECHANISM Filed Jan. 2 1942 I5 Sheets-Sheet 2 INVENTOR JAMES ooNAveN wl-:LLs

/ LATTORNEY May 20, 1947- J. DL WELLS 2,420,763

Y .30T SEAL COOLING MECHANISM/ Filedan. 2, 1942 f 3 Sheets-Sheetl 5 Y INVENTOR. AMES DONAVEN WELLS ATTQRNEK Patented May 20, 1947 HOT SEAL COOLING MECHANISM James D, Wells, Floral Park, N. Y., assignor to American Machine & Foundry Company, a corporation of New Jersey Application January 2, 1942, Serial No. 425,419

4 Claims.

This invention relates to a wrapping machine and has particular reference to seal forming mechanism of a wrapping machine.

Most of the wrapping machines in present day use employ heat to seal the overlapped and folded ends of a heat scalable wrapping material such as wax paper or cellophane. The tendency has been to operate these machines at faster and faster rates of speed to reduce the wrapping cost per article. When this is done, long cooling belts heretofore employed for holding hot seals together until they have set have been rendered unsatisfactory because they absorb considerable heat, and after running awhile are found sufficiently hot or warm to prevent the full setting of the bonding medium. Such belts have several other disadvantages such as their dependence upon atmospheric* temperature (which would vary from day to day), the accumulation of wax thereon, and the greatamount of floor space required.

To overcome these handicaps, it hasbeen found necessary in the art to resort to refrigerating systems in order to dissipate the heat from the i hot seal as quickly as possible. This, however,

increased the initial cost as well as the cost of maintenance and operation of the machine which formerly used long cooling belts, and had a tendency to offset any saving effected by running the machine at a higher rate of speed. As a result, the trade was faced with somewhat of a dilemma as to which'type of machine they should buy. If they used a fast operating machine, the initial maintenance and operating cost would be increased; if they used a slower machine, these costs would be lower. Hence, there was great need for1 a simple belt type cooling device which would seal packages satisfactorily at a high rate Another object is to employ a uid for cooling members engaging with the hot seals of wrapped articles.

Another object is to provide for a succession of cooling devices which will lower the temperature of hot seals rapidly and still be economical to operate and which will occupy only a small amount of floor space.

Other objects and features of the invention will appear as the description of the particular physical embodiment selected to illustrate the invention progresses.

In the accompanying drawings, which form a part of this specification, like characters of reference have been applied to corresponding parts throughout the several views which make up the drawings, in which:

Fig. l is a side elevation of a portion of a wrapping machine equipped with the improved cooling mechanism.

Fig. 2 is a plan View of the same.

Fig. 3 is a detail view showing a modied means for cooling the `side belts of the mechanism.

Fig. 4 is an end view of a modified means for cooling the side and bottom belts.

Fig. 5 is a sectional side elevation of the same taken from line 5 5 of Fig. 4.

Fig. 6 is a plan view of a modified form of the invention showing vertical side cooling belts arranged in tandem.

The present invention is adapted for use with wrapping machines, particularly breadwrapping machines of the type shown in U. S. Patents Nos. 2,082,945 and 2,133,503, to which reference may be had for further details not herein shown or described. Although particularly adapted for cooling and setting the hot seals of articles wrapped with wax paper, it is also adaptable for use with other thermo plastic coated or heat sealable wrapping materials.

Referring to the drawings, the loaf of bread or article A, which has been completely enfolded in its wrapper during its passage through the machine, is pushed by a pair of pusher arms l!) through the set of end sealer plates l l and l2, of conventional construction, forming a part of the wrapping machine. The sealer plates Il and I2 are provided with heating elements I3 for heating them to the proper temperature for fusing together the folded end flaps of the wrapper as it is pushed past the sealer plates II and I2. The bottom sealer plate I4, over which the wrapped articles travel, is provided with a heater element I5 for heating plate I4 to a suitable temperature As the packages pass over the heat sealingl plate I4 and between the heat sealing plates II and I2, the bottom seam and the end folds are heat sealed and fused together. Upon emerging from the heat sealing plates, the seals are still hot and must be held in place and Vcooled promptly in order to set the seal before it has a chance to open. The bottom seal of a wrapped loaf is frequently made up of only one overlapped seam and presents a simpler sealing problem than does the end seal. The end seal is made up of a large number of creases and overlapped folds. The satisfactory cooling of the end seal has therefore presented a greater cooling problem because of the thickness and air pockets in the end seal. The present invention, however, has provided a solution for these problems. For this purpose there has been provided an endless bottom conveyor belt 2I which may be made of some suitable material such as canvas, and two endless side conveyor belts 22 and 23 which may also be made of similar fabric.

A fabric belt such as canvas is particularly well suited for this purpose because of its ability to absorb moisture until substantially saturated. A three-ply canvas belt operates very Well for this purpose because there is a-minimum of shrinkage and expansion, and the thickness still permits the belt to absorb and carry a large amount of moisture and still be flexible. Belts of other thicknesses and other absorbent material, however, may also be employed with satisfactory results. These belts serve to hold the seal in place, advance the article, and at the same time cool the seals by dissipating the heat therefrom, particularly by means of absorption, conduction and radiation of the heat from the belt. In order to increase the eciency of the canvas belts, they are saturated with water so that they will pick up the heat from the hot seal and quickly conduct the same to the exposed surfaces of the belt and thereby allow the heat to escape from the loaf. It is believed that this condition is facilitated by the greater conductivity of a saturated belt over a dry belt. The moisture on the belt forms a closer contact between the hot seal and the belt by eliminating air pockets. Some of the excess moisture evaporates directly from the end of the wrapped articlev as the cooling belts engage with the seals to be set, and some from the belt, all of which c0- operate to give a maximum initial cooling eiect so as to set the hot seal at the earliest possible moment.

To obtain the maximum cooling of the belts prior to their engagement with a hot seal, moisture is applied to the belts immediately after they leave the hot seal to allow a maximum heat loss due to evaporation and radiation to take place on the return run of the belts. Under certain conditions it may be desired to further facilitate and increase the rate of evaporation from belts 22 and 23. In this connection, a conventional fan 79 may be employed to blow a current of air upon the return run of belts 22 and 23. The hot seal cooling and setting efficiency of the belts will thus be maintained when they again engage with the hot seals of other newly sealed articles.

A roller 25, which is driven by suitable means (not shown), imparts motion to the belt 2| running over an idler roller 24. The returning lower run of belt 2| contacts and thereby rotates a felt covered moisture applying roller 2S which is partly submerged in water contained in a tank 21. The water tank is carried by a plate 28 supported by uprights 29.

The belts 22 and '23 are suitably driven by Vpulleys 32 and 33, respectively, and run over idler pulleys 38 and 3|. At the terminus of the conveying run of each of the belts 22 and 23 is located a vertically mounted circular brush 34 so positioned as to contact and be rotated by the returning run of each of the belts. Brushes have the advantage of distributing moisture evenly and into all indentations of the belt. The brushes 34 are supported by a holder 35 having upper and lower projecting ears 35 provided with adjustable trunnions 31 on which the brushes rotate. The upper ear of each holder 35 supports a bracket 38 which has a vertical extension 39 supporting a conventional drip valve 48 having means for adjusting the amount of Water supplied to the outlet pipe 4I which feeds the brush. The water is supplied from a supply tank 42 having pipes 43 leading to the valves 40. The tank is mounted on a plate 44 and supported by uprights 45, said uprights supporting the bars 46 which serve to carry the holders 35. Each h'older 35 is equipped with a guard 41 which partly surrounds the brush 34 and serves as a safety means and also as a shield for the water spraying from the brush.

Referring to Fig. 3, a roller 48 having a felt covering 49 may be used in place of the circular brush 34 to apply moisture to the side belts 22 and 23. The wick portion 58 ofthe felt covering extends beyond the bottom of roller 48 and is partly submerged in the water provided in tank 5I. In this manner the wick portion 50 absorbs water and moistens the entire felt covering which contacts and applies moisture to the cooling belts 22 and 23. It will be understood that the rollers 48 will be rotated by the returning run of their respective belts 22 and '23. Roller 48 (as shown in Fig. 3) turns on adjustable trunnions 52 and 53, the former being mounted in a boss 54 of the tank and the other carried by a holder 55 secured to the tank 5i.

The drip valves, such as 40 (shown in Fig. l), may also be used in conjunction with rollers 48 to feed water to the upper portions of said rollers to assure a more even distribution of moisture.

Referring to Figs. 4 and 5, the side belts 22 and 23 and the bottom belt 2I receive moisture issuing from conventional adjustable spray devices 53 and 5l carried by the U-shaped bracket 58 attached to the machine. Each vertical wall 59 of bracket 58 is equipped with a spray device 56 so positioned as to direct the moisture onto the redirect the moisture over the entire width of the belt 2|. A sprayer distributes moisture on the belt evenly and avoids contacting the belt physically, thereby reducing wear and tear upon the belt and moisture applying mechanism.

The water issuing from the spray devices 56 and 51 may be supplied from any suitable source of supply and led to the respective sprayers by pipes 60.

Fig. 6 shows a modied form of the invention wherein a series of side cooling belts (il-64 are arranged in tandem to engage withthe hot end seals of newly sealed articles advancing from he'at sealing plates which may be similar to those shown in Fig. 2. Each of belts lil-64 passes over conventional drive pulleys 'll- 14 respectively, and over free pulleys 'l5-18 respectively, in substantially the same manner as shown in Fig. 2. A horizontal cooling and conveying belt 65 operates in substantially the same manner as belt 2| shown in Fig. 2.

Circular moisture-applying brushes BB--BS are positioned adjacent to the belts lil-64 to apply moisture at the beginning of the return run of each' belt. Moisture applying pipes 10 furnish each of the brushes with moisture, the amount of which may be regulated by suitable valves, such as 40, shown in Fig. l. The brushes may be positively rotated by conventional drive pulleys, or may be freely mounted for engagement with the side belts so that they will be rotated by the endless belts lil-464 which are positively driven.

Newly sealed articles are advanced, in the direction indicated by the arrow (Fig. 6), from the heat sealing plates. As the articles are advanced, canvas conveyor and cooling belt 65 cools and sets the bottom seal of the newly wrapped loaf or article. The vertical side belts 6l and B2 engage with the hot end seal and travel therewith to preset and pre-cool the hot seal. These belts remove a large percentage of the heat from the end seal almost immediately upon engagement `with the hot seals. This is believed due to the fact that the hotter an object, the more rapid will be its rate of cooling and vice versa. The temperature of belts 6I and 62 will also be comparatively high and as a result they will give off a large quantity of heat on their return runs. This is due to the fact that the greater the difference in temperature between two adjoining masses, the more rapid will be the exchange of heat energy. In the case of belts 6| and 62, the difference in temperature between the surrounding atmosphere and the belts will also be comparatively great and the rate of cooling, therefore, will be very rapid. When the hot seals of the wrapped article or bread loaf come into contact with belts 63 and B4, a large amount of heat will already have been given up, and these belts will act to lower still further the temperature of the hot seal. It is clear that belts 6I and 62 will run with higher temperatures than will belts B3 and 64. Their ability to remove heat will be correspondingly greater because of the great difference in temperature. By dividing the belt up in tandem, the same amount of space will be occupied but the cooling ability will be greater.

The belts 6 I--B are all saturated with moisture in substantially the same manner as disclosed in Figs. 1 and 2. The moisture added by brushes EE--GS enables a closer contact to be made-between the hot end seal and the side belt. Insulating air pockets between the hot seal and the cooling belt are also avoided. A suflicient quantity of moisture is applied to thoroughly soak the fabric or canvas belts 6|64 so that their ability to conduct heat away from the hot end seal will be materially increased. On the return run, the moisture is given 'a chance to evaporate andthereby aid in cooling the belts (il-54. Ifdesired, a blower similar to that shown in Fig. l might be employed to increase the rate of evaporation and to increase the cooling of belts Eil-64 on their return run.

"The invention above described may be varied in construction within the scope of the claims, for the particular device selected to illustrate the invention is but one of many concrete embodiments of the same. The invention therefore is not to be restricted to the precise details of the `structure shown and described.

What is claimed is:

1. .A seal setting device for a wrapping machine in which heat is applied to the seals of a Wrapped article to join the overlapped portion `thereof comprising, a conveyor for forwarding wrapped articles having hot seals along a predetermined path of travel, aplurality of water absorbent belts arranged in tandem on opposite sides of said conveyor, and means for supplying water to said belts to keep them wet.

2. A seal setting device for a wrapping machine in which heat is applied to the seals of a Wrapped article to join the overlapped portion thereof cornprising, a horizontal conveyor belt made of a fabric material for forwarding articles bearing hot seals, a moisture applying roller positioned `to engage and apply moisture to the return run of said horizontal belt, a pair of fabric belts disposed on opposite sides of said horizontal conveyor belt for engaging the hot end seals of articles and travel therewith for a predetermined distance to pre-cool said seals, means for applying moisture to said fabric belts, a second pair of fabric belts also disposed on opposite sides of said horizontal conveyor for engaging with the pre-cooled seals of said articles and traveling therewith a further predetermined distance to cool the seals still more, and moisture applying means for applying moisture to said second pair of fabric belts.

3. Sealing mechanism for wrapping machines comprising in combination, a conveyor for forwarding wrapped articles having thermo plastic seals along aprcdetermined path, water absorbent belts extending along said path and engaging said seals, means for supplying water to said belts t0 keep them wet, and means for blowing a current of air on the moistelned portions of said belts to facilitate evaporation from said belts to lower their temperature.

4. In a wrapping machine having devices for forming overlapped end folds on a wrapper folded about the girth of an article and heat sealing said folds, and instrumentalitles for advancing the heat sealed packages transversely, the combination with a pair of oppositely disposed endless moisture absorbent fabric conveyor belts each having a vertical operating run traveling in the same direction and at the same speed as the packages conveyed by said instrumentalities and arranged to engage with the heat sealed end folds of the conveyed packages to cool the same, each of said conveyor belts also having a return run disposed out of engagement with the heated sealed package folds, moisture appliers arranged to saturate said belts with moisture at the beginning of their return runs to increase the heat conductivity of said belts along said operating runs and thereby increase the amount of heat absorbed from said heat sealed end folds, meams REFERENCES CITED The following references are of record in the le of this patent:

Number UNITED STATES PATENTS Name v Date Bentz June 3, 1924 Gwinn June 30, 1925 Sevigne Jan. 10, 1928 Hilburt Apr. 21, 1936 Lautenschlager Mar. 2, 1909 Frisbie Aug.v14, 1934

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