US3545160A - Method and apparatus for purging headspaces of filled cans - Google Patents

Description

Dec. 8, 1970 c. E. JANTZE ETA!- 3,545,150

I ,METHOD AND APPARATUS FOR PURGING HEADSPACES OF FILLED CANS 5 Sheets-Sheet 1 Filed Dec. .5, 1968 INVENTORS CLYDE E. JANTZE EDWARD A. ARNOTT EARLE v scorr BY/{mi/ f ATT'Y Dec. 8, '1970 c. E. JANTZE ETAL 3,545,150

METHOD AND APPARATUS FOR PURGING HEADSPACES OF FILLED CANS 5 Sheets-Sheet Filed Dec.

INVENTORS CLYDE E. JANTZE EDWARD A. ARNOTT EARLE v scorr BY "Z, v

w %T X Dec. 8, 1970 c. E. JANTZE EI'AL 3,545,160

METHOD AND APPARATUS FOR PURGING HEADSPACES OF FILLED CANS 5 Sheets-Sheet 4 Filed Dec.

Dec. 8, 1970 c. E. JANTZE ETAL 3,545,160

METHOD AND APPARATUS FOR PURGING HEADSPACES OF FILLED CANS Filed Dec. 5, 1968 5 Sheets-Sheet 5 INVEN TORS CLYDE E. JANTZE EDWARD A. ARNOTT EARLEM SCOTT ATT'Y.

United States Patent 3,545,160 METHOD AND APPARATUS FOR PURGING HEADSPACES OF FILLED CANS Clyde E. Jantze, Riverside, Edward A. Arnott, Blue Island, and Earle V. Scott, La Grange Highlands, Ill., assignors to Continental Can Company, Inc., New York, N.Y., a corporation of New York Filed Dec. 5, 1968, Ser. No. 781,426 Int. Cl. B65b 31/02 U.S. Cl. 53-7 Claims ABSTRACT OF THE DISCLOSURE A can intake arrangement and gassing nozzle to purge air from the headspaces of filled cans as they approach chucking position on the seaming turret. The body infeed conveyor, infeed turret and seaming table are positioned for maximum effective gassing travel. A slot along the end feed guide delivers a gas jet which sweeps under the flanges of ends approaching the infeed position. A gas nozzle adjacent the infeed turret pocket delivers inert gas into the pocket through two banks of ports partially surrounding the pocket. One bank along the upper face of the nozzle case directs gas jets to sweep the headspace, while gas jets from a lower bank sweep under the body flange. A by-pass slot between the port banks diverts a portion of the flow in a fan jet, to preclude induction of air into blind spaces between ports.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to can filling and closing methods and apparatus, and more particularly to that portion of the operation involved with intake to the closing machine and purging treatment of the cans and covers or ends, preparatory to the closing and seaming operation. The turret-type closing machines described in Kronquest et al., U.S. Pat. No. 2,255,707, issued Sept. 9, 1941, and Laxo, U.S. Pat. No. 2,540,001, issued Jan. 30, 1951, are representative of closing machines for use with which the invention is particularly well suited, although not limited thereto.

The prior art Handling and closing conditions generally preclude filling beverage cans to the lip. In order to minimize spillage, it is necessary that some headspace remain after the fill. The headspace is then preferably purged and inerted before sealing, particularly in the case of such beverages as beer, which may deteriorate rapidly, in the presence of air. Without purging, a significant volume of air will remain in the headspace after closing and seaming.

A convenient and economical method of purging the headspace is referred to in the trade as undercover gassing, wherein an inert gas is directed into or across the headspace below the cover or end to force or induce air from the space, in order to establish and maintain an inert atmosphere in the headspace just before and up to the time at which the end is chucked to the body.

Generally, gassing of filled cans has been performed by means of gassing nozzles on the infeed turret directing a gas stream through the space between the end and the container. This arrangement has been fairly satisfactory at low production rates, but prior designs have not performed acceptably at high production rates, for two principal reasons. First, prior nozzles do not provide fully effective gas-flow patterns, in that an excessive amount of air outside the headspace is induced with the gas stream reducing efficiency. Consequently, a substantial quantity of air is trapped in the headspace with the residual gas,

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when the can is closed. Second, with the arrangement of apparatus heretofore employed, the period during which the end is in 'sufficient proximity to the can prior to closing is too short for a full scavenge of the headspace at any practicably achievable gassing rate and efficiency. Tests with prior methods and apparatus have shown that earlier initiation of gassing merely wastes the gas. Prolongation of the gassing stage along the seaming table is impractical by reason of aggravated spillage hazard, together with high cost and complexity of the equipment. In any event, gassing on the seaming table is undesirable by virtue of reduction in available seaming travel, which should be maintained at maximum value, if high quality seaming is to be performed at high production rates.

SUMMARY OF THE INVENTION An object of this invention is to provide, in association with a can filling and closing line, an improved method and apparatus for undercover gassing of filled cans approaching the closing and seaming operation.

Another object of this invention is to provide a gassing arrangement in association with an infeed turret, whereby to purge the headspace of a filled can with maximum efiectiveness under conditions of short gassing exposure.

Yet another object of this invention is to provide an undercover gassing method and apparatus which precludes or minimizes excessive air entrainment or induction into the gas stream.

A still further object of this invention is to provide a gassing arrangement of a design which best assures effective distribution and proportioning of gas to the gassing areas and thorough scavenging of air from the undercover and head spaces.

The foregoing objects are achieved by a novel method of gassing, implemented by a novel arrangement and structure of the gassing apparatus. With a particular positioning of the infeed conveyor, infeed turret and seaming table, the can and its end are brought into position for initiation of gassing at a point optimally in advance of chucking position, providing maximum effective gassing travel before the end is chucked to the body. A slot over the nozzles, along the end guide rail, sweeps under the end flange. The nozzle ports are arranged in dual banks, one above the other, with the upper, primary bank sweeping the headspace. The lower, secondary bank sweeps under the body flange, minimizing entrainment of air from beneath the flange. The end carried immediately above the body acts as an upper shield.

In association with the dual bank arrangement, the nozzles and manifolds are proportioned for optimum gas quantity and distribution, to insure thorough purging of the headspace in the gassing time provided. A portion of the gas flows through a slot between nozzle banks to by-pass the ports and to preclude air induction through dead spaces between ports.

The foregoing and other objects, advantages, and details of the invention will be best understood from the following description read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic and diagrammatic plan of infeed apparatus associated with a turret-type closing machine, arranged according to this invention;

FIG. 2 is a partial, diagrammatic plan, similar to FIG. 1, showing can and end infeed relationships on a larger scale;

FIG. 3 is a plan view of the infeed turret represented in FIG. 1, with distributor and valve assembly removed to expose principal parts of the nozzle assembly;

FIG. 4 is an end elevation of the one nozzle sector taken on line 44 of FIG. 3, showing ports arranged according to this invention;

FIG. 5 is a horizontal section through a nozzle sector taken on line 55 of FIG. 4;

FIG. 6 is a horizontal section through a nozzle sector taken on line 66 of FIG. 4;

FIG. 7 is a vertical radial section through a nozzle sector, taken on line 77 of FIG. 4;

FIG. 8 is a fragmentary plan view of the end feed guide and can feed turret adjacent to the seaming table, with portions broken away to show the upper gassing slot;

FIG. 9 is a partial vertical section on line 99 of FIG. 8, showing the inlet and passage to the upper gassing slot;

FIG. 10 is a radial section through the infeed turret taken on line 1010 of FIG. 3, showing a can body and cover in position upon transfer from the infeed conveyor to the seaming turret during gassing, just prior to clos- FIG. 11 is a schematic sectional view, similar to FIG. 10, showing gas flow patterns through the nozzle, at approach and across the can headspace; and

FIG. 12 is a schematic perspective along the top of a can, showing gas flow patterns across the headspace.

DESCRIPTION OF PREFERRED EMBODIMENT The invention here shown and described is designed for use in conjunction with a turret-type closing machine, which performs the function of seaming the ends to the filled can bodies. The infeed to the closing machine involves bringing together the filled can, delivered from the filling machine along a conveyor, and the cover or end, delivered from a hopper or stack, fed in synchronism with the can feed conveyor. In order to be effective, the gassing must be performed in the interval between the point at which the end is brought over the top of the can, in proximity thereto, and the point at which the end and the can flange are mated for chucking, preparatory to seaming.

Since it is desirable to devote as much of the can travel on the seaming table as possible to the seaming operation, the can and its end should be delivered to initial gassing position as far in advance of the seamed-can discharge point as possible. Gassing preferably is provided just before can and end reach chucking position on the seaming table. If then the gassing effectiveness is also enhanced, the combination of these measures greatly facilitates the operation of the closing machine at a high production rate, without a sacrifice in the quality and integrity of the finished product.

Referring now to the plan of FIG. 1, cans C are shown traveling from left to right along an infeed conveyor line 10 toward the closing machine turret 11. At the same time, ends E are fed from stacks 12 by an end feed turret 13 along guide 14, passing over and along infeed turret toward conveyor line 10 and closing machine turret 11. The can and end feeds are synchronized so that a can C and an end B arrive together at turret 11. Such feed apparatus is well known in the art, not forming part of this invention, and the apparatus need not be described here in detail.

As end guide 14 and can conveyor line 10 converge near closing machine 11, each end B passes across and above an incoming tangent point T on chuck circle 11a, along the projection of conveyor line 10.

Experience has shown that undercover gassing cannot effectively begin until the can and end centers are quite near to coincidence. Otherwise, much of the effect is wasted outside the headspace, and excessive dilution by air induction results. It has been found that with a representative beer can size, the end and can eccentricity should not exceed about /2 inch when gassing is initiated. The position along the periphery of the infeed turret 15 at which a given value of S will obtain can theoretically be predetermined within limits by instituting appropriate departures in the paths of cans along line 10, ends along guide 14 or both upon approach to seaming turret 11. However, inertial effects at high speeds predicated for high production rate preclude substantial departures from true linear and rotary motions indicated, particularly with respect to jostling and sloshing effects on the cans, aberrations in alignment and juxtaposition at the desired conjunction point T. Reasons of manufacturing economy in the turrets, guides and related parts of the apparatus, particularly in feeding devices, also dictate against resorting to expedients involving substantial divergence from uniform feed courses just before closing.

Establishment of the desired gassing relationship for the earliest feasible can capture position at feed turret 15, and relative to seaming turret 11, is achieved by so positioning axes of turrets 11 and 15 that the respective centers 11a and 15a are angularly displaced from a line XX at right angles to can feed line 10 through point T, with chuck circle 11b and end feed circle 15b tangent at T. Thus, line YY through centers 11a and 15a lies at an angle A relative to line XX, the centers being swung about point T in the direction to bring center 15a toward line 10 at the infeed side of point T, that is, clockwise in the arrangement of FIG. 1.

The beneficial result of the positioning described is best understood by reference to FIG. 2. The broken arc represents end feed along circle 15b toward point T in the direction of the arrow, with the feed radius centered on line XX. Line XX passes through point T in the direction of the arrow. In that case, ends pass through a point S at a distance S from can feed line 10, corresponding to the maximum can and end separation at which gassing may be effectively initiated. S -T represents the effective gassing travel. The end feed circle 15b is centered on line YY, at angle A to line XX. In this case, the center of end E passes through a point S at a distance S from line 10, corresponding to separation S, at a distance S T from point T, substantially longer than travel S T.

As seen in FIG. 1, the provision of full gassing travel in advance of completed intake at T affords maximum practicable travel on turret 11 to discharge point D, at tangency with the discharge turret 16, substantially 270 are, devoted to chucking, spin acceleration, seaming and release to discharge. In consideration of apparatus space requirements, 270 seaming turret travel is substantially the maximum practicably obtainable. Experience has shown that it is desirable and necessary to devote such travel as fully as possible to the seaming operation, particularly at high production rates and correspondingly high linear can speeds. k

In order to realize rates on the order of 1000 can per minute and upward, extremely high gassing effectiveness is requisite. This invention achieves such effectiveness by virtue of a novel gassing pattern, nozzle and associated apparatus. A top plan view of the apparatus is shown in FIG. 3. Nozzle sectors 17 encircle and rotate with turret shaft 20 about a vertical axis. The number of sectors 17 is determined according to the velocity and spacing of cans arriving at the infeed turret 15 along conveyor line 10 (FIG. 1). An arcuate wall 21 defines a can pocket P, sized to accommodate the largest can diameter of a limited range with which a given assembly is to be used.

For best results, the turret size and number of sectors 17 are selected for spacing P -P as nearly as possible the same as the can infeed spacing along conveyor line 10, thus obviating or minimizing intake acceleration or deceleration. For manufacturing convenience and economy in detail finishing, the nozzle sectors 17 are best made by casting or fabricating a complete ring, finishing the continuous cylindrical and planar surfaces, drilling bolt-holes 22, and then sawing along radial lines 23 through holes 22, midway between pockets P. However, a continuous ring may be used, if preferred, in which case holes 22 may be of such number and location as necessary for clamping the ring comprising nozzles 17 on the turret 15.

The design of the nozzle 17 is conducive to exceptionally high gassing eflectiveness. Details of nozzle 17 are best seen in FIGS. 4 to 7 inclusive. Referring first to FIG. 4, a series of ports 23 constitute primary gassing ports, ranged near the upper face 24 of nozzle 17. A secondary series of ports 25, smaller than primary ports 23, constitute a second bank in a plane parallel to the plane of ports 23, near the lower face 26 of nozzle 17. As best seen in FIGS. and 6, all of ports 23- and 25 communicate with the manifold chamber 27. The primary ports 23 are arranged along an arcuate wall 28. The secondary ports 25 are arranged along an arcuate wall 29, forward of wall 28.

Referring now to FIG. 7, inner wall 28 depends from the top of nozzle 17, transecting the upper portion of chamber 27. Outer wall 29 extends upward from lower face 26, transecting the lower portion of chamber 27, partially overlapping wall 28. Thus, walls 28 and 29 define an arcuate passage 30, communicating with chamber 27, and leading to an arcuate space 31, opposite ports 23. A pair of struts 32 serve as bracing, as best seen in FIGS. 4 and 5. A central group of ports 23 face space 31 between struts 32, while left and right groups face spaces 31a and 31b, outwardly of struts 32, so that struts 32 do not present a flow obstruction.

FIGS. 8 and 9 show the provisions for gassing under the cover flange. Ends approach gassing position along the guide rails 18 and 19, which define the path 14 between them. Rail 18 overlies the can feed turret 15 and is concentric therewith, as best seen in FIG. 1. Rail 18 lies between cover plate 60 and the top plane of nozzles 17 passing underneath. Rail 18 is provided with a long arcuate slot 61 concentric with and radially inward of the cover flange rail 18a. At its approach end, slot 61 communicates with port 62 in cover plate 60, which is connected by line 63 to the CO source (not shown). Except at port 62, the upward opening of slot 61 is closed by the overlying rail member 18 which is clamped to cover plate 60 by any suitable means (not shown). Running clearance between the bottom face 24 of rail 18 and the top face 64 of nozzle 17 constitute the shallow slot 65, opposing the flange E of an end E carried on the rail 18a. Slot 65 is in communication with the CO supply line 63 through the arcuate slot 61. Gas, supplied through pipe 63, floods the slot 61 and then fans out in a high velocity jet through the slot 65, as best seen in FIG. 8, flooding and enveloping the end flanges E (FIG. 8), as the ends E move along the rail 18a toward superposition over corresponding can bodies approaching on the can feed line. The gas flood zone extends from the position at which each end E begins lapping can C to a primary gassing zone, where end E is nearly superposed over a can C. The pocket defined by flange E is purged of air prior to and until the purge effected by gas from nozzle 17, minimizing the entrapment of air around the flange E and possible subsequent entrapment in the headspace as the end B is lowered onto the can C, preparatory to seaming.

For the reasons above given in the description associated with FIGS. 1 and 2, the arrangement there shown of the turrets and feeds for early juxtaposition of cans and ends substantially enhances the total gassing effectiveness including that ascribed to the end flange purging shown in FIGS. 8 and 9.

The manner in which the ports are arranged for gassing operation is best understood from consideration of FIG. 10, which shows the gassing assembly and its relation to the infeed turret 15, the seaming turret 11, the can body C, the end E, and the other apparatus associated with under-cover gassing at intake to the seaming turret 11. In this view, the relationship of the various elements is represented with can C and end E superimposed just before releasing end E from the rails 18 and 19 of guide 14. That is, the can and end are here shown in the positions reached substantially at point T, FIG. 1. Pusher 33, stop 34, and infeed mold 21, serve to position can C on support chuck 35, carried by seaming table 36. Hub 37, aflixed to shaft 20, carries the gassing assembly, comprising clamping ring 38, mold ring 39, spacer ring 40, nozzles 17, and wear ring 41, for rotation relative to the distributor assembly consisting of face valve 42, gasket 43, and cap 44. The several parts of the gassing assembly are held together and clamped to the hub 37 by means of several series of bolts or cap screws (not shown) provision being made therefor in the uppermost parts by series of holes or taps 22, 45, 46, and 47 (FIG. 3), it being understood that the intermediate and lower parts of the assembly are provided with matching taps or holes as required. The arrangement is designed to facilitate interchangeability of the several parts with corresponding parts required to accommodate cans of different diameters, or other infeed spacings with which the basic turret assembly is to be used. The nozzles 17 may be removed and a blind ring substituted, for use of the turret with can lines not requiring gassing.

As best seen in FIG. 3, wear ring 41 is provided with a series of sector ports 48, equal in number to the number of nozzles 17, centered about radii common with the center radii of nozzles 17. Referring again to FIG. 10, wear ring 41 rides in contact with valve member 42 along interface 49. Valve member 42 has a single port 50, whose shape and size are the same as those of ports 48, valve member 42 being so positioned that, as each rotating nozzle 17 traverses its gassing arc, corresponding port 48 sweeps across port 50, being in full registry substantially at the position of FIG. 10.

Port 48 communicates with chamber 27 in nozzle 17 through connecting ducts 51 and 52, in spacer 40 and ring 39, respectively.

OPERATION As seen in FIG. 10, nozzle 17 is positioned opposite can C and end B with ports 23 facing the space under end E and over the top of can C, ports 25 being directed toward can C just below body flange F. Inert gas, such as CO for example, is supplied to distributor 44 from any suitable source. In a brewery, CO is regularly available from plant supply lines, which may be tapped and connected to distributor 44 through regulators and control valves (not shown) in any well known manner to supply distributor 44 whenever the can-closing line is in operation.

With a given nozzle 17 in the gassing position of FIG. 10, gas flows from distributor 44 through valve port 50, sector port 48, and ducts 51, 52 to manifold chamber 27, from which the gas is delivered through the primary ports 23, secondary ports 25, and arcuate passage 30. As best seen in FIG. 5, ports 23 and 25 are arranged along concentric arcs defining fan perimeters.

The gassing pattern is illustrated by FIGS. 11 and 12, which show schematically the movement of gas, indicated by filled arrows, and scavenged air, indicated by open arrows. Referring first to FIG. 11, ports 23 constitute flow paths from chamber 27 directly into discharge space 31 and thence toward the space between end B and can C, across the headspace H above the liquid fill level L. A smaller volume flows through ports 25, the total area of which is substantially less than that of ports 23. A substantial volume flows through the relatively large bypass 30, aided by the inductive effect of the jets from ports 23 flowing across the opening of by-pass 30 into space 31. Thus, gas leaves the chamber 27 in three stream layers, the two upper streams, propagated from ports 23 and bypass 30, reuniting in principal part as a consolidated stream along flange F at the periphery of headspace H, thence flowing across the headspace, under the principal directional and inductive effects of the jets from ports 23.

Gas jets from ports 25 impinge on can-wall surface W in a plane a short distance below flange F. The stream so generated flows around and along surface W in both directions from the plane of the view, sweeping the space defined by nozzle wall 29 and surface W, in a direction generally transverse to can C. Impingement of the highvelocity jets on the surface W diverts a portion of the secondary stream to sweep along the underside of flange F and a portion to flow generally downward along surface W. The downward diversion precludes induction of air from space below upper wall surface W, that is, from below the plane of ports 25.

The total area of ports 23 and by-pass passage 30 is proportioned to the total area of ports 25 approximately as the ratio of the volumes to be swept by the primary and secondary streams respectively. With proportionate adjustment for the effect of diversions and other flow conditions, the respective stream velocities transversely of can C will be substantially the same and there will be no significant tendency to cross-flow between the primary and secondary streams through the narrow passage between flange F and Wall 29.

Now referring particularly to FIG. 12, the central group of primary ports 23a are parallel, establishing a central gas stream across the mid-zone over the top of can C. The boundary groups 23b and 230, on axes radially of the can C, establish converging streams flowing in toward the boundary segments of the headspace, being then in part deflected by impingement upon the central stream, to flow generally parallel therewith across the boundary segments. The primary flow thus sweeps the entire headspace with minimal wasteful marginal flow outside the can lip beyond the headspace at its cross-stream diameter. The full sweep thus established minimizes induction of air into boundary spaces upstream and laterally of the headspace, thus insuring maximum eflectiveness in entraining and purging air from the headspace. At the same time, the full-fan stream from the by-pass 30 supplements the primary flow and substantially precludes induction of air through up stream spaces between the jets issuing from the primary ports 23, particularly the spaces between groups 23a and 23b, and between 23a and 230.

The timing of the gassing stage is such that gassing begins just before the end/can position of FIG. 2 and continues at least until the end B is chucked to can C, the gassing intensity being maintained at suificient value to preclude air infiltration at gas cut-off. The timing is determined by appropriate sizing of the inlet ports 48 and valve port 50, for any given number of nozzles 17. In the example shown and described, with 12 nozzles at 30, inlet ports 49 and the valve port 50 each have an arcuate span of 19, providing 38 gassing travel of each nozzle from cracking to cut-01f. Thus, while there is necessarily some volume fluctuation with change in total inlet port area as each inlet port passes the valve port, there is never a no-flow condition through the valve port, since any given inlet port is in communication before its predecessor is cut oil. The adverse elfects of extreme throttling and surging flow are avoided, while maintaining maximum effecitve flow to each nozzle without excessive wastage. The fixed valve port 50 (FIG. 8) is positioned to center on a radius about midway between turret radii through points S and T (FIG. 2), so that the peak gas flow obtains during the gassing travel of each nozzle between S and T.

Since the nozzle ports may become contaminated, crusted or plugged, as by spillage from cans, occasional cleaning or sterilization may be required. This servicing is readily performed by connecting the turret and manifold assembly to a hot water or steam line, with switchover control, whereby from time to time the ports can be scoured and flushed by running the turret with hot water or steam fed through the gassing system. Such oc casional cleaning can be scheduled with other :maintenance operations, minimizing down-time.

It will be understood that the particular proportioning and arrangement of parts shown is by way of example only. The example used for illustrative vpurposes is that of a machine designed and constructed to handle standard twelve-ounce beer cans, delivered to the closing machine at a rate on the order of 1000 cans per minute and upward, spaced about 3 /2 inches. For this requirement, best results are achieved in accordance with this invention by use of a twelve-pocket turret. The nozzle 17 for each pocket, as illustrated in FIGS. 4 to 6 inclusive, has 13 /8 inch primary ports 23 grouped 3-7-3 along a arc of about 1% inch radius, 11% inch diameter secondary ports 25 equally spaced along a arc of about 1 /2 inch radius, and by-pass 30 about A inch wide.

It will also be apparent that application of the invention is not limited to round, metal cans, the invention being readily adaptable for use in methods and apparatus associated with hermetically closing or capping jars, bottles and other filled containers of various shapes and sizes. Manifestly, steam, nitrogen or other gas may be used for purging, according to the residual headspace atmosphere best suited to the particular product fill involved.

Those skilled in the art will be able to devise other arrangements, proportions and dimensions of the parts, and other variations and modifications for operating conditions other than the exemplary ones here given by way of illustration, without departing from the spirit and scope of the invention, as defined in the appended claims.

What we claim is:

1. Apparatus for a can closing line comprising: a closing turret; a can infeed turret concentrically carrying undercover gassing nozzles; an arcuate end feed guide concentric with said infeed turret; a linear infeed conveyor for delivering a succession of filled cans to said closing turret, said conveyor and said guide being arranged to deliver cans and ends respectively to a point of concentric superimposition upon said closing turret, said point being on a line diametric of both said turrets, the apparatus being further characterized in that said diametric line is inclined to a line through said point perpendicular to said conveyor line, with the center of saidinfeed turret at that side of said perpendicular line from which cans approach said point along said conveyor line; and inertgas jet means associated with said can infeed turret, including first means adapted to direct some of said gas against the flanges of covers approaching said point along said guide, second means adapted to direct some of said gas between said end and said can when said end is superimposed over said can, and third means adapted for activation simultaneously with said second menas to direct some of said gas against said cans along and under the lips of said cans; whereby substantially to preclude trapping of air in headspaces of said cans when said cans and ends are seamed on said closing turret.

2. A nozzle assembly for gassing a filled can having a flanged end positioned closely above the can lip, preparatory to closing, comprising: a shallow housing having a chamber bounded by side walls; an outer wall adapted partially to surround a can, said outer wall extending between said side walls along the bottom of said chamber to a right less than the depth of said chamber; an inner wall substantially equidistant from said outer wall, said inner Wall extending between said side walls along the top of said chamber to a depth less than the depth of said chamber, defining a passage along said bottom leading from said chamber to said outer wall; a bank of first ports in said inner wall communicating with said chamber; a bank of second ports in said outer wall communicating with said passage; and a plate above said housing, spaced therefrom, the clearance between said plate and said housing constituting a slot communicating with atmosphere above said ports; whereby, upon opposing said nozzle assembly to said can with said outer wall below said lip, and therewith supplying gas to said chamber and said slot under pressure, gas from said slot sweeps the flange of said end, gas from said first ports sweeps the head space between said end and said can, while gas from said second ports sweeps the wall of said can below said lip.

3. A nozzle assembly according to claim 2, wherein the plan configuration of said housing is generally that of an annulus sector, whereby a plurality of said housings may be abutted in series to constitute an annular nozzle ring adapted for carriage upon a turret.

4. A nozzle assembly according to claim 2, wherein said passage is a first passage, said inner, outer and side walls defining a second passage communicating with said first passage, said second passage terminating in an uninterrupted opening forward of said inner wall, whereby, upon so opposing said nozzle and so supplying said gas, an undivided stream of gas from said second passage merges with gas from said first ports to constitute an undivided gas stream flowing toward said headspace.

5. Apparatus for gassing headspaces of a series of filled cans received by said apparatus, comprising: a rotatable can feed turret; end guide means associated with said turret defining a channel concentric with said turret for guiding a flanged end into close superposition over each can of said series, as said can is received by said apparatus; a pocket member carried by said turret, said pocket member having a plurality of pockets adapted successively to receive can of said series with the lip of each said can upward of a corresponding pocket; a plurality of nozzles constituting a ring carried by said turret above said pocket member, there being a nozzle aligned with each said pocket; an elongated slot opening into said channel in a plane upward of said nozzles, along said guide means; a first discharge bank in said nozzle positioned to oppose the space between said can and a superposed end, upon reception of a can in a corresponding one of said pockets; a second discharge bank in said nozzle positioned to oppose the upper wall portion of said pocketed can; a manifold communicating with said discharge banks; and means for supplying gas under pressure to each of said slot and said manifold separately, whereby said apparatus is adapted to cause gas from said slot to sweep the flange of an end approaching said one pocket and independently thereof to cause gas from said first bank to sweep said space, while gas from said second bank sweeps said can wall portion.

6. Apparatus according to claim 5, wherein said nozzle includes side walls bounding said manifold; an arcuate outer wall extending upward between said side walls from the bottom of said manifold to a plane below the plane of said first bank, said outer wall being concentric with said pocket; an arcuate inner wall extending downward between said side walls from the top of said manifold to a plane above the plane of said second bank, said inner wall being concentric with said outer wall and more remote from said pocket than said outer wall; first ports in said inner wall constituting said first bank; said second ports in said outer wall constituting said second bank; said outer wall and said side walls defining a discharge chamber for said first bank, said inner wall and said side walls defining an inlet passage communicating between the manifold chamber and said second bank, said outer wall and said inner wall with said side walls defining an uninterrupted by-pass communicating between said inlet passage and said discharge chamber; whereby to propagate a first stream from said first ports, a second stream from said second ports, and an uninterrupted by-pass stream merging with said first stream upstream of said space, to

10 constitute an uninterrupted primary stream substantially precluding induction of air into said space between jets propagating said first stream, while said second stream substantially precludes induction of air from below said lip into said primary stream.

7. A method of purging air from space between the contents of a container and a flanged cover being carried over the mouth of said container, preparatory to sealing said cover to said container along the lip thereof, comprising: directing a substantially undivided first gas stream immediately under and across said cover and along the flange thereof; propagating a series of gas jets along a line laterally remote from said space, thereby constituting an initially divided second gas stream, and directing said second stream toward and across said space generally transversely of said container; directing a third gas stream against the outer wall surface of said container generally transversely thereof immediately below said lip; and, simultaneously with the propagation of said second stream, directing a substantially undivided fourth gas stream into said second stream substantially throughout its transverse extent and between said line and said space, all said streams being directed in the same general direction transversely of said container, thereby inhibiting induction of ambient air into said space during purging thereof.

8. A method according to claim 7, wherein said container is round, further including initially forming said second stream in jet groups along an arcuate said line concentric with said container, including a central group directed along parallel lines toward the mid-zone of said space and boundary groups at opposite sides of said central group directed along lines radially inward of said container toward segments of said space bordering said mid-zone, thereby efiecting consolidation of said second stream with said fourth stream, establishing a substantially undivided principal stream flowing through said space, and inhibiting marginal flow beyond said space at the diametral line of said container crosswise of said principal stream.

9. A method according to claim 7, and establishing relative volume flow rates of said principal and third streams generally proportional to the ratio of the undercover and under-lip spaces respectively swept thereby, thereby establishing generally the same velocities of said principal and third streams in parallel above and below said lip respectively and substantially inhibiting cross-flow therebetween.

-10. A method according to claim 7, wherein said cover and container are moved along converging paths to a location at which said cover is superposed relative to said container, including initiating said first stream prior to superposition of said cover and prior to initiation of the other said streams, and thereafter maintaining said first stream at least until superposition of said cover over said container and throughout the flow period of the other said streams.

References Cited UNITED STATES PATENTS 2,692,715 10/1954 Doudera 53-110 TRAVIS S. MCGEHEE, Primary Examiner US. Cl. X.R.

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