US2897851A - Apparatus for de-airing filled containers - Google Patents

Description

v Filed sept. 26, 1957 D. N. MELDRUM APPARATUS FoR DE-AIRING FILLED CONTAINERS Aug. 4,1959

- s shets-sheef 1 8 67 INVEN'TOR DQNALD N- MELDRUM BY XM fw ATTORNEY Aug. 4, 1959 D. N. MELDRUM APPARATUS RoR DE-AIRING FILLED CONTAINERS 'Filed sept. ze, 1957 3 Sheets-Sheet 2 INVENTOR normw N. MELDRUM @Trona/ey D. N. MELDRUM APPARATUS FOR DE-AIRING FILLED CONTAINERS s sheets-sheet s Aug. 4, 1959 Filed Sept. 26, 1957 lll/N lNl/ENTOR DONALD N-MELDRUM HT TQRIIIEY rlUnited States Patent A() APPARATUS FOR DE-AIRIN G FILLED CONTAINERS `Donald N. Meldrum, Malvern, Pa., assigner to National Foam System, Inc., a corporation of Delaware Application September 26, 1957, Serial No. 686,507

' 2 Claims. (Cl. 141-70) The present invention relates generally to apparatus for generating and dispensing foam, and more particularly to improvements in means for applying foam to containers in a moving canning line for the purpose of excluding air from the containers just prior to sealing the same, whereby to preserve the'packaged product as well as to preserve the container, as by inhibiting corrosion thereof.

An important object of the present invention is to provide a` foam applicator unit with a multiplicity of arms or nozzles and a single control valve, manually operable while the apparatus is in motion, for electively varying selectively the rate of foam discharge' from said arms .or nozzles, as desired. f Another important object of the present invention is to provide apparatus wherein a foam applicator and the canning line operate continuously in predeterminedV timed relation to automatically position a container under each arm or nozzle and toV hold it there during the foam discharge period of said arm or nozzle, whereby to reduce foam waste toa minimum. Still another object of the present invention is to provide such apparatus that' is simple in design, economical in manufacture and easy to install, operate and service.

Other ,objects and advantages of the present invention will appear more fully hereinafter,.it being understood that the invention consists substantially in the combination, construction, location and relative arrangement of parts, all as described in the accompanying drawings'and as finally pointed out in the appended claims.

V,In the drawings:

f` Figure l is an elevation showing a pressure vessel or tank in which the foam forming solution is storedA under pressure.

' Figure la is a plan view Ashowing a liquid-gas'mixing head, the applicator unit, and the canning line.

Figure 2 isa`fragmentary elevation showing Vthe appli- "cator unit and a container in the process of being'lled by the applicator unit. A

Figure 3 is a transverse section through the foam geh 'erator tube showing two of the discharge arms or nozzles 'out of registry and thevother two partially in registry with -the discharge port of the foam generator tube.

Figure 4 is a vertical longitudinal sectionl through the Afoam generator tube showing the discharge opening or portl partially opened, as indicated by line 4-4` of Figure la.

Figure 5 is a vertical section showing the piping system n connected into the vessel of Figure l.

Figure 6 is a plan view-of the piping system, as indicatedby line'6--6 ofFigure l. .'Referring particularly to thel drawings, the exemplary apparatus constructed in accordance with and embodying the principles of the present invention comprises means, generally designated A, for delivering a foam-forming `solution and an inertgas to a chamber B whereinthe lsolution-and gas are intimately admitted preparatory to the generation of foam.

Referring particularly to Figures 6, it be observed that the solution delivering means A includes a pressure tank 10 suitably supported .upon piers 11-11, which tank is provided with a top opening fitted with a cover 12 that may be removed as necessary for lling the tank with a suitable foam-forming solution. The bottom of the tank is tted with means, generally` designated 13, for draining the tank.A A source (not shown) ofinert gas under super-atmospheric pressure communicates directly with both the interior of the tank 10 and theinterior of the mixing chamber B through the medium of a pipe system now to be described. t Y This source of gas under pressure is connected to a coupling 14 (see Figure 6), which latter is connected by a nipple 15 and elbow 16 to a pressure gauge 17. The gauge is connected by a nipple 18 to a three-Way valve 19, and the latter is connected by a nipple 20 to a safety valvet21. The safety valve is connected by a nipple. 22 to a four-way coupling or cross 23, which latter is also connected by a nipple 24 to the top of the tank 10. Connected to the three-way valve 19 is an auxiliary section 25 of the pipe system that is open to atmosphere and which is supported from the top of the tank 10 through the medium of a bracket 26. y

Connected to the coupling 23 by a tting 27 and ex'tending downwardly freely through the bottom end of the coupling 23 well into the tank 10 is a discharge tube 2S the vupper end of which is connected to aV branch 29 ,of the pipe system through which liquid under pressure delivered is from the tank 10. "Connected into the pipe branch 29V by Van elbow 30 anda nipp1e'31 is a strainer 32, which latter is connected to the main run of the branch line 29 by a coupling 33. l Connected to the cross 23 by a coupling 34 is the main run of a ysecond branch line 35 of the -pipe system, by which inert gas conducted under pressure tov the cross23 passesY through the latter (see Figure 5), around the upper end of the discharge tube 28 connected to the liquid discharge branch line 29, and into the branch line 35, as well as through the cross 23 and nipple 24, downwardly about the discharge tube 28, 'into the tank 10. The conduits or pipe line branches 29 and 35 are connected into the means aforesaid for mixing the liquid and gas together, which means is in the form of a mixing chamber generally designated B, now to bedescribed. Y Referring particularly to Figures 1a and 4, the branch lines 29 and 35 arerconnected into the opposite sides of lthe mixing chamber B and communicate with passages,

respectively designated 36 and 37, that are formed internallyof the mixing chamber, which passages communif cate with a central bore that is formed internally of the mixing chamber with fore and aft sections thereof, resectively designated 38 and 3 9, communicating through a constricted section, designated 40. The passage 37 leading from the gas line 35 communicates with the section of the central bore, which latter is plugged, as at 41, while the passage 36 leading from vthe solution line '29 communicates with the foresec'tion of the centralv bore, whichis tted with a foam discharge and applicator unit 'presently to be described. Any means may be utilized for mounting the mixing head in fixed position.

Referring particularly to Figures la, 2, 3 and 4 the vapplicator unit aforesaid, generally designated C, includes a tube 42 that is threaded into the body of the mixing .chamber B and which is thereby supported preferably in a horizontal position. Fitted over the free end portion of the tube 42 `is a cap 43 (seeFigure 4), thatfissecured against displacement by a set screw '44, and :fitted Vover an intermediate portion ofthe tube 42 iswa tubular frbushing .45.v Threaded through the cap 43 isha screw 'p46 that terminates at lone end in a cylindrical head 47 which isslidably fitted into the tube 42,.r ,The opposite endiof the screw 46`is provided with a handwheel 48 for operat` 2,897,851 e ,l f

ing the screw 46 and thereby shifting the head 47 axially within the tube 42.

Revolubly fitted over the bushing 45 is an axially iixed tubularsleeve 49, and fitted overy the outer end portion of the latter for rotation therewith is a Vcollar 50 that mounts a set of four tubular arms or nozzles which extend radially outwardly in equal angular spaced relation. These arms, respectively designated 51, 52, 53 and 54, are identical, and therefore a description of one of the arms, eig., the arm 51, will suffice for a full understanding vof the present invention.

The arm 51, constituting a foam discharge nozzle, is a tubular member that is threaded into the collar 50. Threaded upon the outer end portion of the arm 51 is a sleeve 55, and threaded upon the latter is a cap 56. Operatively interposed between the sleeve 55 and the cap 56 is a suitable screen, preferably in the form of a perforated plate 57. It will be noted thatl the cap 56 is provided with a discharge opening, designated 56a, that is somewhat greater in diameter than the internal diameter of the sleeve 55, and that the latter is internally tapered, as at 58, to provide aared discharge extremity for the foam discharge nozzle, thereby allowing for expansion of the foam as it discharges from the nozzle.

Fitted into the collar 50 and disposed adjacent the inner end of the tubular arm 51 is a screen or perforated plate 59, and packed into the arm'Sl, between the screen plates l line position of the applicator, the arm 51 registers fully with the opening 61, while the arms 52, 53 and 54 do not register therewith, in consequence of which there is a maximum discharge of foam from the arm 51 and no discharge of foam from the arms 52, 53 and 54. As the applicator unit is turned in a counterclockwise direction, the arm 51 moves out of registry with the opening 61, while the arm 52 moves into registry therewith, in consequence of which the discharge of foam from the arm 51 gradually decreases and finally terminates, While simultaneously the discharge of foam from the arm 52 begins and then gradually increases to a maximum. Referring particularly to Figure 3, when the applicator unit has made a quarter turn, each of the arms 51 and 52 is in one-half registry with the opening 61, but the arm 51 is moving out of registry, while the arm 52 is moving into full registry. The action just described takes place with each successive pair of arms as they pass under the opening 61.

Referring particularly to Figure 2, in the left hand side broken line position of the arm 51, the discharge of foam through the arm 51 is just beginning. In the full line position, the discharge of foam through the arm 51 is at a maximum. And in the right hand side broken line posil tion of the arm 51, the discharge of foam through the arm 57 and 59, are a multiplicity of glass or plastic beads 60. 'Referring particularly to Figures 3 and 4, for establishing Vcommunication between the interior of the foam generator tube 42 and each of the arms 51, 52, 53 and 54, successively, in response to rotation of the assembly including the tubular sleeve 49, collar 50 and the several arms aforesaid upon the bushing 45, the tube 42 and bushing 45 are provided with aligned apertures that conjointly aiord an opening 61 in the underside of the tube 42 and bushing `45. As is best shown to Figure 3, this opening is preferably somewhat elongated, and at the outer surface of the bushing 45, the opening has an arcuate extent corresponding to the angular spacing of the several arms, i.e., 45 degrees. The opposite side walls of the opening 61, designated 62, respectively extend tangentially relative to the inner surface of the tube 42, as shown, while the length of the opening 61 considered axially of the "tube 42 preferably approximates the internal diameter of the `foam discharge tubular arm or nozzle 51. The openings in the collar 50 that receive the several arms extend radially inwardly, as at 63 Iand successively register with the opening 61 as the assembly aforesaid is turned, whereby the desired communication is established.

The gas introduced into the mixing chamber B through the branch line moves through the passage 37 andV then through the central bore portions 39, and 38, inV the order listed, while the foam-forming liquid introduced into the mixing chamber B through the branch line 29 moves through the passage 36 into the central bore portin 38, where it is intimately mixed with the gas, and `from whencethe mixture of gas and liquid is discharged into the tube 42.

The gas-entrained foam-forming solution thus forced under pressure through the tube 42 is discharged therefrom through the port or opening 61 successively into the several ` arms 51, 52, 53 and 54, and as the mixture traverses each'arm through the tortious path afforded by the beads 60 it is converted into foam having a high expansion factor. Thus, as each of these arms moves into registry with the opening 61, the foam-forming mixture discharged through the latter enters the opening 63 and then passes successively through the screen plate 59, the tortious path formed by the beads 60 that are packed in the arm, and the screen plate 57, being finally discharged as foam from the arm through the opening 56a that is formed in the cap 56, at the outer extremity of the arm.

51 is terminating. In this connection, it will be noted that the construction and arrangement of parts is such that inthe operation of the apparatus the flow of foam through the opening is never interrupted by reason of rotation of the arm or nozzle assembly, in consequence of which variation in the back pressure is held to a minimum.

Disposed in underlying relation to the applicator unit is a suitable horizontal belt conveyor, generally designated D, including a belt 64 that is trained over a pulley 65, which latter is carried by a shaft 66. This shaft is provided with a spur pinion 67 that is in mesh with a spur gear 68. The latter is mounted upon a counter shaft 69, which also mounts a chain sprocket 70. This sprocket is connected, through the medium of a chain 71, to a *second chain sprocket 72, which latter is mounted upon the tubular sleeve 49 for rotation of the applicator unit in predetermined timed relation to the conveyor belt.

In the operation of the apparatus, the containers that are to be charged with the foam from the applicator unit are loaded upon the belt 64 in single file and in predetermined equally spaced relation. These containers, designated 73, pass under the applicator, and there is one such container for each of the several arms each time the applicator makes one revolution. The rate of foam discharge is regulated by manipulation of the handwheel 48 whereby to vary the size of the opening 61 as desired.

vReferring particularly to Figure 2, each container apfoam and it remains continuously in position for receiva Referring particularly to Figures 2 and 4 in the full 75 ing the foam discharged by said arm froml the beginning till the end of the discharge period, in consequence of which foam Waste is held to a minimum. In this connection, it will be understood that while the rate of foam discharge is determined by the effective size of the opening 61, the total volume of foam discharged from an arm also depends upon the length of the discharge period, which may be varied by changing the rate of operation of the apparatus as a whole.

As most 'clearly appears in Figure 2 the apparatus is preferably so arranged as to insure that each of the foam discharge nozzles 51, 52, 53 and 54 moves from the lefthand dotted line position shown in the figure to its righthand dotted line position in the same time interval that it takes for a can to be filled with foam to move along the conveyor D from the left-hand dotted line position of the can shown in Figure 2 to its right-hand dotted line position. Thus, as the cans are successively moved along the conveyor, in the direction of travel indicated in Figure 2, each of said cans is provided with a predetermined complement of foam delivered from a single foam discharge nozzle moving in unison with the can.

It will be noted also that the arrangement is such that as the foam discharge nozzle moves with a given can to ll the head space thereof with the requisite volume of foam, the discharge of foam from the nozzle is automatically controlled, the foam being delivered initially into a can at a limited rate of discharge, with the rate of discharge increasing to a maximum whenv the can is in direct axial alignment with the foam discharge tube (as shown in full lines in Figure 2), following which the rate of discharge of the foam decreases to zero. Preferably the spacing of the cans on the conveyor relatively to the foam discharge nozzles is such that when a given nozzle approaches a position at which the discharge of the foam is about to be completely interrupted, the can being lled with foam from said nozzle is relatively in such position beneath the nozzle that upon continued movement of the can along the conveyor D the remaining trickle of foam which issues from the nozzle before the latter is completely shut oli is directed into the top of the can, thereby insuring against discharge of the foam outside of the can as well as against waste of foam.

Of course, the rate of foam discharge from the nozzles 51 to 54 may be controlled by axial adjustment of the plug valve 47 hereinabove referred to and described, which valve may be also positionally adjusted to completely shut oli any discharge of foam should that be necessary during operation of the apparatus.

With a four-arm or nozzle assembly applying foam to a canning line in which the cans pass by the assembly at the rate of 240 cans per minute, the assembly must make 60 r.p.m. However, while the exemplary applicator unit is a four-arm or nozzle assembly, it is not intended to limit the invention thereto. For example, a six-arm or nozzle assembly rotating at 40 r.p.m. might be utilized.

In the exemplary arrangement of the apparatus, foam is discharged alternately irst from only one arm, then simultaneously from two arms. For example, as the applicator unit rotates, foam is discharged lirst only from the arm or nozzle 5l, then simultaneously from the arms 51 and 52, and then only from the arm 52, etc. However, it is not intended to limit the invention to this arrangement of the apparatus. For example, utilizing a six-arm or nozzle arrangement, the arcuate extent of the opening 61, measured on the outer surface of the bushing 45, could be made twice the angular spacing of the several arms, i.e., 120 degrees. In this event, foam would be discharged alternately lirst simultaneously from only two of the arms, then simultaneously from three of the arms.

The apparatus and method of the present invention, while applicable to the packaging of any products in sealed containers from which air is desirably replaced by an inert gas, may be particularly employed to advantage in the packaging of food products which are normally subject to spoilage by air sealed in the containers during the process of filling the same. Of course, when employing the apparatus and method hereinbefore described for the packaging of food, the foam-forming liquid is composed of substances which are non-toxic and are preferably edible, such liquid being preferably of the type produced by alkaline hydrolysis of suitable proteinaceous material, such as hydrolized soy-bean.

The foaming agent may be any one or more of various animal or Vegetable substances which alter the surface tension of water sutlciently yto produce a foam stable enough to withstand not only the high temperature conditions which generally prevail in food canning operations but also the physical and chemical shock involved in the generation and application of the foam. The foam also should be quite stable over the time interval elapsing between its application to the head-space in the filled container and the seating and sealing of a cover to the container, and also the foam should be'of such uniform bubble size as to insure that each container during any given iilling operation is filled with foam containing gas and liquid in substantially constant proportion.

In addition to hydrolized soybean, the foaming agent may be gelatin, casein, egg albumin or other such nontoxic material. With the apparatus as hereinbefore described, and employed gas at any desired super-atmospheric pressure, a fluid foam may be obtained from a solution containing 0.01 percent protein nitrogen (as from hydrolized soybean), while varying degrees of foam stiffness of the foam being directly proportional to the concentration of the protein nitrogen. With thesoybean protein hydrolysate, the optimum protein nitrogen concentration in the foam-forming aqueous solution (as contained in the tank 10) is in the range of from 0.01 to 0.3 percent (as determined by the Kjeldahl method).

The amount of foam that may be produced in one continuous operation by the apparatus and method of the present invention is limited only by the supply of pressurized gas and the available volume of the foamforming solution in the tank 10. If a 15 expansion foam is produced, gallons of such solution would produce 1500 gallons of foam.

The inert gas which is employed in intimate admixture with the foam-forming liquid to produce the desired foam should, of course, also be non-toxic when the foam is employed in food packaging, examples of such gas being carbon dioxide and nitrogen, which may be employed individually or in any desired combination.

It will be understood, of course, that the present invention is susceptible of various changes and modiications which may be made from time to time without departing from the general principles or real spirit thereof. For example, the apparatus could be provided with an applicator unit having one stationary arm or nozzle,

and a quick acting valve (for example, a solenoid valve) i controlled by a switch actuated automatically to interrupt the delivery of foam when there is no container in position on the canning line to receive foam discharged from the nozzle. The actuation of such solenoid valve could be controlled by photo-electric means which includes a light source for projecting a beam of light across the path of travel of the cans and a photo-electric cell unit which is activated upon interception of the light beam by a can to close the valve controlling the delivery of foam. Alternatively, such solenoid Valve could be controlled by a suitable trip mechanism or other mechanical device operated bythe cans moving along the canning line.

Accordingly, it is intended to claim the invention broadly, as well as specifically, as indicated by the appended claims.

What is claimed as new and useful is:

l. In an apparatus for replacing air with an inert gas in lled containers, a mixing head, a pressure vessel for storage of a foam-forming solution, a source of supply of an inert gas under pressure, conduit means for -conducting said pressurized gas directly to the interior of said storage vessel to pressurize the solution therein and for conducting said pressurized solution and gas each directly to the interior of said mixing head for mixing the same together for provoking the formation of foam, an applicator unit including a stationary conduit communicating with said mixing head for receiving the solution gas mixture therefrom, and foam generating and discharge means revolubly mounted upon said conduit, said foam generating and discharge means being provided with a plurality of nozzles extending radially of the conduit and operative to register successively with a discharge port formed in said conduit, each of said nozzles being packed with discrete elements that conjointly form therebetween a multiplicity of restricted tortuous passages for flow of the solution-gas mixture.

respectively in position beneath said nozzles for successively receiving the controlled charges of foam therefrom.

2. In an apparatus for replacing air with inert gas in filled containers, a chamber for receiving and intimately adrnixing under pressure a foam-forming solution and an inert gas, a conduit communicating with said chamber for delivery of said solution and gas mixture to an outlet port provided in said conduit, valve means for regulating the etective orifice size of said outlet port, said valve means including a valve element shiftable axially of said conduit to selectively close said port or open it to any desired degree, foam generating and discharge means revolubly mounted upon said conduit for intermittent registry with said outlet port, conveyor References Cited in the le of this patent UNITED STATES PATENTS 981,768 Ketterer Jan. 17, 1911 2,289,852 Mondloch July 14, 1942 2,433,071 Stevenson Dec. 23, 1947

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