US2857935A

US2857935A - Gas charging apparatus and method

Info

Publication number: US2857935A
Application number: US571425A
Authority: US
Inventors: Jr Newton E Spiess; Henry L Henze
Original assignee: Kraft Inc
Current assignee: Kraft Inc
Priority date: 1956-03-14
Filing date: 1956-03-14
Publication date: 1958-10-28
Anticipated expiration: 1975-10-28

Description

N. E. SPIESS, JR.. EI'AL 2,857,935

GAS CHARGING APPARATUS AND METHOD Oct. 28, 1958 4 Sheets-Sheet 1 Filed March 14, 1956 NEWTON E. HEN RY L 4 v f/le/r A 7' ram/e x5.

O t, 28, 1953 N. E. s nzss, JR.,, ETAL GAS CHARGING APPARATUS AND METHOD 4 Sheets-Sheet 2 Filed March 14, 1956 INVENTORS. NEWTON E. SPIESS,JR. a HENRY HENZE 2 MAN ATTORNEYS.

Oct. 28, 1958 N. E- E R, ETA!- 2,857,935

I GAS CHARGING APPARATUS AND METHOD Filed March 14, 1956 4 Sheets-Sheet 35 FIG. 4.

I I DRIFT START CIRCUIT 6|. I i L Q.| I

L HOLD cmcuw CLOSED I L \..r VALVE OPEN HP. VALVE OPEN l CYCLE 360 INVENTORS. NEWTON E. SPIESS,JJR. 8| HENRY L. HENZE file/r A TTORNEXS Oct, 28, N'. E. SPIESS, JRQ, ETAL 2,857,935

'GAS CHARGING APPARATUS AND METHOD Filed March 14, 1956 4 Sfieets-Sheet 4 /0Z TIME 1 I00 A Lu-"r Afi-ionm LIFT CAM (70) A FIGJI.

- m STAGE (LOW PRESSURE) VALVE CAM (74) OPEN F16. I2. CLO$ED J 2nd STAGE (HIGH PRESSURE) VALVE CAM(75) PRESSURE PSI FIG. 13.

2'0 MANIFOLD PRESSURE P PRES URE SI NORMAL PRESSURE CYCLE 2K); MANIFOLD PRESSURE AgNORMAL PRESSURE CYCLE IN VHV TORS.

S ARTING WITH CONTAINERS NEWTON E. SPIESS,JR. a ALREADY CHARGED ONCE Y HENRY L. HENZE United States Patent 2,857,935 I I GAS CHARGING APPARATUS AND METHOD Newton E. Spiess, Jr., and Henry L.,Henze, Islip, N. Y., assignors, by mesne assignments, to National Dairy Products Corporation, New York, of Delaware Application March 14, 1956, Serial No. 571,425 15 Claims. (Cl. 141-3) This invention relates to methods and apparatus for charging containers. In particular, it relates to methods and apparatus for introducing gaseous substances such as whipping agents, propellants or the like into containers capable of withstanding pressure.

A critical problem involved in the gas charging of containers, particularly those partially filled with a product which absorbs gas, is the control of the pressures in the container during and after the charging operation as well as the control of total quantity introduced. While charging the container, the critical pressure limitations imposed by the strength of the can must not be exceeded and, overall, the quantity of the charging medium introduced must be maintained at a precise value if a uniform product is to be obtained. In gas-charged whipped cream containers, for example, a variation of 18% in the final pressure of the charged container results in clearly perceptible differences in the quality of the whip, the product at one extreme of the range being dry and stiff and at the other extreme loose and wet. A further problem which is troublesome in the manufacture of containers of gas-charged products is the possibility that a once charged container will find its way inadvertently into the input end of the charging apparatus thereby subjecting that container to a second charging operation. Under normal circumstances, using conventional gas charging techniques, this can result in the rupture of the container and attendant hazards to equipment and personnel. Moreover, in certain cases the process of charging containers results in back pressures which force the prod uct being charged back into the gassing system, resulting in contamination.

It is, therefore, an object of the present invention to provide an improved method and apparatus for charging containers.

It is another object of the invention to provide an improved method and apparatus for charging containers and products therein with gas whereby precisely controlled quantities of gas can be injected for the purposes of facilitating controlled discharge of the product. and for beneficially altering the character of the product.

It is another object of the invention to provide a gas charging method and apparatus whereby repeated cycling of one container through the charging operation is unlikely to result in such severe multiplication of internal pressures as to rupture the container and whereby contaminating backflow is eliminated.

It is still another object of the invention to provide improved apparatus whereby gas charging needles can be injected into containers to facilitate improved gassing operations and to decrease the possibility of needle breakage.

A representative embodiment of the present invention is described in detail in the following specification having reference to the accompanying drawings in which:

Figure l is a view in front elevation, partly in vertical section, of an apparatus for charging containers with gas;

. Figure 2 is a fragmentary view in transverse section N. Y., a corporation "ice through the center portion of the apparatus of Figure 1 taken on the line 2-2 looking in the direction of the arrows;

Figure 3 is an enlarged view in vertical section of one of the needle guiding assemblies of the apparatus of Figure 1;

Figure 4 is a graph plotting the vertical displacement of a container and the timing of several functions related thereto throughout one cycle of the apparatus of Figure 1;

Figures 5, 6, 7 and 8 are a succession of views in vertical section showing a needle and guiding assembly of Figure 1 and an associated container passing through four stages of a gassing cycle;

Figure 9 is a diagram illustrating a gas pressure control system which can be utilized in the apparatus of Figure 1;

Figure 10 is a graph illustrating the action of the container platform lifting mechanism for one cycle of operation of the apparatus of Figure 1;

Figure 11 is a graph having a time axis corresponding to that of Figure 10 and illustrating the action of the low pressure stage of the gassing operation of the apparatus of Figure 1;

Figure 12 is a similar graph illustrating the action of the high pressure stage of the gassing operation;

Figure 13 is a graph showing the relationship between the manifold pressure and the internal container pressure over a charging cycle;

Figure 14 is a graph corresponding to Figure 13 showing the relationship between the manifold pressure and the internal container pressure resulting from a second charging of the same container; and

Figure 15 is a schematic wiring diagram of the electrical system for the apparatus of Figure 1.

Referring now to the drawings and to Figure 1 in particular, the invention is illustrated as embodied in a gas charging apparatus arranged to charge a plurality of containers C-1, C-Z, C-3 and C4 simultaneously in a so-called batch charging technique, although it will be understood the invention is not limited to batch charging, but can be embodied, for example, in continuous infeed fully automatic systems. The apparatus is constituted broadly of a framework 10 supporting a table surface 11 surmounted by a charging or gassing head assembly indicated generally by the numeral 12 and, disposed beneath the gassing head and the table surface, lifting and valve actuating mechanism indicated generally by the numeral 13 for driving a vertically movable container supporting platform 14 and for controlling the gassing system.

The apparatus operates to raise the several containers C 1 C-4 against a battery of gassing or charging needles 15-1, 15-2, 15-3 and 15-4 to cause the latter to pierce the containers and to be disposed at a sequence of different levels therein, while at the same time and in synchronism therewith, effecting predetermined gassing operations all as described below.

To these ends the assing head assembly 12 includes a fixed cross head 16 secured to a pair of hollow

tubular uprights

17 and 18 in turn secured as by bolting to a cross piece 19 of the frame assembly 10. The charging needles 15-1 15-4 are respectively secured to the cross head 16 by clamping assemblies 20-1, 20 2, 2tl-3 and 204. each of which is arranged to place the hollow bore of the corresponding needle in communication with a gassing manifold 21, which can if desired be furnished with a gas pressure indicator 21a visible to the operator of the apparatus. Gas is introduced into the manifold 21 through a conduit or tube 22 which passes down through the tubular upright 17 to a junction 23 at which it divides into a pair of

parallel branch conduits

24 and 25 having cam operated valve means 26 and 27 respectively. The

branch conduits

24 and 25 come together at a second junction 28 fed by a single conduit 29 adapted to be connected to a suitable source of gas. As shown in the flow diagram of Figure 9, the gas source can comprise for example a conventional gas bottle 36 working through a pressure regulator 31 and a suitable heat exchanger 32 for controlling the temperature of the charging gas to maintain uniform charging conditions. The branch conduit 2 4 can include in addition to the cam perated valve 26 a suitable accumulator or gas reservoir 33 and a flow regulator 33a ,in the form of an orifice plate.

Referring again to ,Figure 1, slidably mounted on the

tubular uprights

17 and 18 beneath the cross head 16 is amovable crosshead 34 urged downwardly by

strong compression springs

35 and ,36 against

limit stops

37 and 38 which can takethe form of tension bolts threaded into the stationary cross head 16 Thus, the movable cross head 34 is adapted to be slid upwardly as a unit through the agency of the vertically movable platform 14 and the battery of containers C-l C-4 interposed therebetween.

The movable cross head 34 includes a plurality of container positioning and needle guiding assemblies identified generally by the reference numerals 39-1, 39-2, 39-3 and 39-4 and corresponding in number to the containers and the charging needles. The needle guiding and container positioning assemblies are all identical, With the assembly 39-4 .being illustrated in detail by the sequential Figures -8. Also, an enlarged, fragmentary view of a needle guide is shown by Figure 3. Referring to Figure 5, the needle guiding and container positioning assembly39-4-comprises a depending container-engaging sleeve 40, preferably, as best seen in Figure 2, formed with an opening 40a in itsside wall to admit the raised valve structure 56 (described below) of the containers. The sleeve 40 is formed'on itslower edge with a lip 41 bevelled and shouldered to receive the margin of the upper end of the container C-4. Formed along the axis of the sleeve 40 is a cylindrical boss 42 through which extends the lower and gently tapering tip 43 of a needle guiding member 44, also seen in Figure 3.

The needle guiding member 44 is preferably formed of plastic, nylon having been found to be very suitable. The shank of the plastic member is formed with a radially enlarged portion 45 adapted to be clamped between flats 46 and 47 formed respectively on the cross head and a threaded gland 46, the latter being threaded onto an upstanding cylindrical sleeve or boss 49 also carried by the cross head 34. The gland is formed with an enlarged aperture fit) through which the upper end 51 of the guide member 44 projects with clearance on all sides to afford limited radial motion. The needle guiding member is formed with a central through bore 52 which slidably receives the stationary gassing needle 15-4. In this fashion, the cross head 34 can be raised by the rising bat tery of containers and lowered by the springs 31 as the containers withd-raw,-with the needle sliding through corresponding through bores 5'2 in the needle guiding member 44. it has been found that bending beyond tolerable limits of the costly charging needles can be controlled by means of this construction, which causes the bending or flexing to be distributed over a relatively large needle length within its elastic limits. Also, the needle is strengthened for that part of the operating cycle at which strains are greatest.

The structure of the containers C-l C-4 can be generally conventional, including a cylindrical body portion 53 (Figure '5), a domed bottom and a top formed at its center with suitable aperture and wall means to receive a valve unit 56. The valve unit 56, which can be formed, for example, in accordance with the disclosure of the ,copending application, Serial No. 211,022, filed February 1-5, 1951, now Patent No.

4 2,761,593, dated Sept. 4, 1956, includes an inner valve head 57, a narrow stem 58 passing through the aperture in the container, and a flexible skirt or cover portion 59. The cover 59 bounds a product chamber which is vented to the atmosphere through a suitable discharge nozzle 60. In operation, .by pressing downwardly along the axis of the valve unit '56, the cover 59 flexes and the valve .head unseats allowing the product to be.discharged under the pressure generated within the container. Gassing of the container through the valve unit 56 is carried out by passing a charging needle along a puncturing axis through the center line of the stem 58, as can be seen in Figures 6 7 or 8. In certain cases, as will be described 'below, the charging needle, in first penetrating the stem, can be made to unseat the valve head 57 to open the container to the atmosphere, thus facilitating purging of unwanted air from the container.

The containers C1 Cl-4, .as stated above, rest on the vertically movable platform 14, being adapted to be slid thereon from the table surface 11. Suitable positioning abutments 60-1, 60-2, 60-3 and 60-4 are fixed to the platform 14 to facilitate the alignment of the several containers with the axes of the corresponding gassing and charging needles 15-1 15-4. The containers can be placed on the platform 14 and the operation of the charging apparatusinitiated through suitable safety gate and switch initiating mechanism forming no part of the present'invention, but disclosed in the copending applicatiomserial No. 584,501, filed May 14, 1956, now Patent No. 2,792,028, dated May 14, 1957.

The platform 14 ,(Figure 1) is mounted for sliding movement vertically on the tubular uprights 17 by means of a pair of elongated sleeves or

bushings

61 and 62 .to which the platform 14 is rigidly affixed. Also affixed to the sleeves 61 and-62 beneath the platform 14 1s a cam follower plate 63, the lower edge 64.0f which is engaged byaroller 65 jo-urnalledbetween a pair of closely spaced plates .66 (only one of which is visible in Figure 1), which plates form a lever arm 67 pivotallyconnected to the frame 10 in a bearing assembly 68. Also journalled for rotation between the plates 66 at the free end of the lever arm 67 is a second roller 69 which rides on a cam plate 70 keyed to a rotating shaft 71 journalled in suitable pedestal bearings 71a and driven from a speed reducing gear box 72 coupled to driving means such as an electric motor 73. The profile of the cam 70 is such that it provides alift pattern for the platform 14 as shown by the graphs of Figures 4 and 10.

Also keyed to the rotary shaft 71 are a pair of cams 74 and '75 engaged respectively by spring biased follower arms 76 and 77. The follower arms 76 and 77 are respectively coupled through suitable linkage 78 and 79 to actuate the values 217 and 26, respectively, in the

gas conduits

24 and 25 which leadto the gassing needles. The cams 74 and constitute low and high pressure cams respectively with the profilesof the cam surfaces being plotted as a function of time at Figures 11 and 12 respectively. .Lastly, there is keyed to the rotating shaft 71 a cam plate 80 engaged by a follower 81 which actuates a control switch means 82, the operation of which is described below.

Referring to the circuit diagram of Figure 15, the control circuit of the apparatus of Figure 1 is illustrated. The motor 73 which raises and lowers the platform 14 through the mechanism 13, is controlled by a motor starting circuit indicated generally by the numeral 83 and which ,is conventional. The starting circuit 83 includes a coil 84 and a series of normally

open switches

85 and 86, 87 and 88, of which the latter three are connected in the circuits to the windings of the motor 73.

A normally open starting switch 89, which can be seen in Figure 1 mounted on the table 11 to the left of the platform 14, is connected across the AC mains by a circuit including a conductor 90, the normally opencontacts of the switchx89, conductors-'91 and .92 and the coil 84 in the startingcircuit 83 of the motor 73. Bypassing the starting switch 89 is a circuit including the cam operated control switch 82. This circuit includes a conductor 93, the normally closed contacts of a manually operated switch 94, a conductor 95, the normally open contacts of the cam operated switch 82, a conductor 96, the normally open switch 85, the conductor 92 and the coil 84. The manually operated switch 94 also includes a set of normally open contacts 97 connected in a by-passing circuit including conductors 98, 99 and 91 around the cam actuated switch 82 and the coil actuated switch 85.

In normal operation the operator places containers to be charged in the machine and initiates the operation by closing the starting switch 89. If preferred, the closing of this switch can be carried out automatically by a guard and gate mechanism disclosed in said copending application Serial No. 584,501, filed May 14, 1956. The coil 84 of the motor starting system 83 is then energized through the circuit including the conductor 90, the then closed contacts of the switch 89 and conductors 91 and 92. This closes the contacts of the

switches

85, 86, 87 and 88 and starts the motor 73. With the. motor 73 in operation, the cam 81 turns to operate the switch 82. The cam 81 is so shaped that after about one second of motor operation it closes the normally open contacts of the switch 82, thereby completing a holding circuit to the coil 84 through the conductor 93, the normally closed contacts of the manually operated switch 94, the conductor 95, the closed contacts of the switch 82, the conductor 86, the closed contacts of the switch 85 and the conductor 92 to the coil 84. The starting switch is then by-passed and can be released to assume its normally open position, an operation normally carried out as soon as the platform 14 begins to rise. Continuous operation of the motor 73 then occurs until the holding circuit is broken by the action of the cam 81 opening the switch 82. Once the circuit has been interrupted, the coil 84 is no longer energized and the

contacts

85, 86, 87 and 88 open to stop the motor.

The manually operated switch 94 can be used, for example, in servicing and cleaning the equipment. By closing the normally open contact 97, a circuit is completed directly to the coil 84, the circuit including the conductors 93 and 98, the closed contacts 97 and conductors 99, 91 and 92.

To accomplish a complete gassing cycle for the containers, the platform raising cam 70 (Figure 1) together with the switch operating cam 81, rotate through one full revolution. The motor 73 is geared through the reduction gear means 72 to reduce the speed so that this cycle takes about twelve seconds. The cams are so shaped that the platform 14 dwells in its down position for approximately four seconds of this time. The cam 81 is arranged to hold contacts of the switch 82 open for a period of slightly more than one second, thus affording about a second of travel before it closes again to commence another cycle. In this fashion accidental momentary closing of the starting switch 89 will not initiate a cycle of the machine.

The operation of the machine to carry out the container charging method of the present invention will now be described as applied to a Whipped cream container having reference in particular to Figures 4-14, inclusive, in which a 12 or 13 fluid ounce container C-4 is first filled by means not the concern of the present invention with 7 fluid ounces of cream, leaving or 6 fluid ounces of air. The several gas pressure values hereinafter described have been determined, for purposes of illustration, for use in a whipped cream operation and in which the container and valve assembly are able to endure up to about 220 p. s. i. before rupture, or as generally occurs, inversion of the concave bottom 54. In Figure 4 there is plotted a graph of the positions of the platform 14 through a complete cycle and, superimposed thereon,

indications of the timing relationship of the action of the electrical circuit and the low and the high pressure gassing stages. The sequential Figures 5-8 show one container in four positions of the charging cycle and Figures 10-14 show, on corresponding time axes, graphs of platform lift, low and high pressure gassing, and the pressure conditions in a container passed through one charging cycle and a container passed through two charging cycles.

A charging cycle is begun with the placement of containers on the platform 14. As illustrated in Figure 5, the container C-4 is disposed beneath the charging needle 15-4 and the corresponding needle guiding and container positioning assembly 39-4. With the closing of the switch 89 the platform 14 rises under the influence of the cam 70, causing the cross head 34 to be forced upwardly and the needle 15-4 to be piloted through the stem 58 of the valve 56 fitted in the top of the container. Prior to this portion of the cycle, which is represented by the rising line 100 in the graph of Figure 10 and also in Figure 4, the cam 74, which turns with the shaft 71, has opened the low pressure gas valve 26 to initiate the flow of gas, which can for purposes of Whipping cream be a mixture of nitrous oxide and carbon dioxide, through the charging needle and into the container. Preferably, the charging needle includes a closely dimensioned orifice at its discharge end for efiicient metering. The low pressure gassing cycle is shown by the pressuretime graph 101 of Figure 11. As the platform 14 approaches its uppermost position (Figure 7 and the section 102 of the graph of Figure 10) the lower tip of the needle guide member 43 can, if purging is desired,

be made to press against the top of the valve 56, opening the valve to the atmosphere. This can be brought about by causing the lower edge 20' of the clamp 20-4 to bear heavily on the end 51 of the plastic guide sleeve 44. The tolerances of the valve opening motions can be increased by the addition of a spring loaded plunger to engage the valve unit. Opening of the valve may in some cases be brought about also by the friction of the needle entering the valve stem before the guide tip 43 engages the top of the valve.

Passing the crest of the raised section 102 of the graph of Figure 10, the container is lowered slightly to reverse the direction of relative movement between the needle and the valve to position the valve seat accurately. If more complete purging is desired the valve can be made to remain unseated or in an open position over the section 103 of the graph, this corresponding to Figure 7. Of course, section 183 can be omitted by appropriate cam design if it is desired to seat the valve promptly to reduce purging effects. Gas at low pressure (Figure 11) enters the container first above and then below the liquid level L while the platform is rising and gas at high pressure (Figure 12) enters over the interval of the

sections

102, 103 of Figure 10. If purging is being carried out, i. e., the valve is being held open, the initial flow of gas forces the air present in the container above the liquid level out through the open valve to the atmosphere. It will be understood that even more effective purging can be obtained by introducing gas initially at the high pressure value, eliminating the low pressure stage. In Figure 8, the lifting cam has turned to present a relatively long dwell represented by the numeral 104 on the graph of Figure 10, in which position the container has been lowered sufliciently to cause the needle guide 43 to become separated from the top of the valve to allow the valve to backseat, sealing the container. At this point, the container can be purged of air, and gas under high pressure under the control of the cam acting in conjunction with the valve 27, continues to be injected into the liquid. The gas injec tion at higher pressure causes agitation of the liquid to promote rapid absorption of the gas and hence effective whipping without creating momentarily excessive pressures in the container. By injecting the major portion of the gas directly into the liquid a higher percentage of gasgoes more quickly directly into solution and the maximum instantaneous pressure occurring in the container for any given final pressure is considerably lower. Container failures are thus reduced. It will be observed that foaming of the cream can be made to occur While the valve is still open, with the rising foam level assisting in purging the combination of air and gas from the top of the container, if this is desired. In any event, the valve should be seated before foam can escape. In general, purging can be used in those cases in which air is undesirable in the finished product and also in which it is desired to minimize the maximum internal pressures built up during charging. With purging, maximum pressures have been found to be about p. s. i. lower. The two stage gassing process of the present invention is, however, particularly adapted to processes in which full purging is not carried out because it minimizes gas losses which ordinarily occur when the valve opens during nedle insertion. With gas losses closely controlled by using the two stage charging operation without the purging process, an extremely uniform product can be obtained throughout a complete run of containers.

It will be recalled that the low pressure gassing conduit 24 (Figure 9) includes both a flow regulating orifice 33a and an accumulator or reservoir 33. At the instant the low pressure valve 26 opens, the reservoir 33 which will have assumed the static pressure of the gas from the downstream side of the pressure regulator 31, comes almost instantaneously into equilibrium with the manifold 21. In the present case, assuming containers are being charged having a pressure enduring property of 220 p. s. i., a gas pressure value at the downstream or output side of the regulator 31 of 210 p. s. i. is selected. The size of the reservoir 33 in relation to the size of the orifice 33a and the volume of the

conduits

22 and 24 and the manifold 21 is such that an instantaneous pressure slightly above that of a fully charged container, i. e., about 125 p. s. i. is achieved. The orifice is sized so that under fiow conditions the manifold pressure remains at about this pressure. Thus, after the reservoir charges the manifold, the pressure will be controlled by the flow through the orifice 33a. When the container reaches the top position, the second or high pressure stage valve 27 opens. While the valve 27 is open, the manifold pressure comes up to the full regulated pressure of 210 The high pressure valve 27 is closed just as the containers begin to fall, after which time the first or low pressure stage again becomes the controlling one. Referring to Figure 13, it will be seen that the pressure in the manifold first establishes itself at 130 p. s. i. and then, after the opening of the valve 27, rises to 210 p. s. i. while the container pressure rises gradually to about 125 p. s. i. When the valve 27 closes, the first stage orifice limits the flow of gas in such way that pressure in the manifold is maintained above the container pressure and during this period a very small amount of gas enters the container due to the small pressure differential. The manifold pressure meantime falls off gradually until such time as the charging needle is withdrawn from the valve of the containers to vent to the atmosphere, although the pressure gradient is always positive. At no time, therefore, does the container pressure exceed that in the charging lines so that there is no possibility of backfiew of the product into the gassing lines which would result in contamination. It will be observed that the spring depressed cross head 34 will remain positioned so that the needle guide member is closely adjacent the container valve 56 while the charging needle 15-4 is withdrawn, thus insuring that the needle does not pull the valve from the container.

Also, it will be observed that for the major portion of the charging cycle, the pressure ratio across the orifice in the charging needle is not less than 2:1. In accordance with the disclosure of the pending application, Serial No. 154,062, filed April 5, 1950, now Patent No. 2,723,- 790, dated November 15, 1955, this results in uniform metering of gas into the container, and close control can be had over the ratio of gas to cream to achieve precise standards.

Refering to Figure 14 there is shown a graph of the pressure relationships which obtain in the event a container is inadvertently recycled through the machine to be charged twice, a condition which normally would be expected to result in either rupture of the container or backflow of the product in the container into the gassing lines. A container having a fully charged pressure of about 125 p. s. i. is first subjected to the low pressure gassing stage of 130 p. s. i. There being a small pressure differential here favoring the upstream side of the needle orifice, no flow of the product into the needle obtains. Shortly thereafter, the high pressure stage goes into operation with the opening of the valve 26 subjecting the container to a relatively long duration with a pressure differential across the needle orifice of approximately 85 p. s. i. Less agitation will of course occur than during the initial charging. The pressure in the container will rise to a value of approximately 175 p. s. i. at the time of shut off of the gas flow and at no time does the internal pressure of the container exceed that in the gas lines. The manifold pressure does not drop to the low pressure value of 130 p. s. i. immediately after the shut: ting off of the high pressure valve. This is the result of the action of the orifice 332a feeding gas to the manifold from a regulated source of higher pressure than that in the containers and the action of the needle orifices to maintain the manifold pressure. will have stored gas at 210 p. s. i. which will tend to endure until the time the needle is withdrawn from the container due to the fact that there is relatively little flow across the needle orifice due to the small pressure differential thereacross. As in the first charging'cycle, the pressure gradient is positive throughout. In connection with the graph of Figure 14, it should be understood that the purging operation (effected by the surfaces of the cam 70 resulting in the

curve sections

102 and 103 of Figure 10) is assumed not to have occurred. This has been done to show the least favorable conditions which could obtain in the operation of this system insofar as container pressure is concerned.

It will be apparent, however, that to carry out the purging operation on a once charged container would result in some loss of the product through the momentarily opened valve. As a practical matter, it has been found that satisfactory results and in some cases more accurate pressure control can be achieved for certain products, such as whipped cream, without recourse to the purging operation before charging. To prevent purging, the cam 70 and needle guide 43 are, as stated, arranged to avoid pressing on the top of the valve 56 during needle insertion, and the cam portion affording the curve section 103 is eliminated. While ordinarily it is sometimes difficult to avoid some degree of opening of the container valve due to friction during needle insertion, gas losses can be effectively minimized by use of the preliminary low pressure gassing stage. The use of the low pressure stage assures, however, that a backflow of cream into the gassing lines is avoided, even when a container is inadvertently charged twice.

While a representative embodiment of the invention has been described above, it will be understood that the invention can appear in other structural embodiments. Thus, for example, rather than a so-called batch charging system as disclosed in which a group of containers are loaded manually and charged simultaneously, a continuous system using an infeed conveyor can be used to carry sequentially through the charging cycle, the gassing Also, the reservoir 33" heads moving with the conveyor. The invention should not, therefore, be regarded as limited except as defined by the following claims.

We claim:

1. In apparatus for charging containers with gas, a container charging member comprising a hollow needle, a container support spaced from the needle, said support and needle being relatively movable to be brought together to cause the needle to enter a container on the support to introduce gas therein, a needle guide normally disposed adjacent the end of the needle to support the needle against lateral movement as it entersthe container, means to mount the needle guide and needle for relative movement axially of the needle, means to carry the needle in an axially fixed position, means to move the container support toward the needle, said needle guide being mounted for movement in the direction of movement of the support and including abutment means to be engaged by a container on the support to be moved thereby, yieldable resilient means to urge the needle guide toward the support and a container thereon, means on the needle guide to engage a valve of a container on the support to vent the container to the atmosphere as the needle enters the container, and means to pass gas into the container through the needle while the container is vented to the atmosphere.

2. In apparatus for charging containers with gas, a container charging member comprising a hollow needle, a container support spaced from the needle, said support and needle being relatively movable to be brought together to cause the needle to enter a container on the support to introduce gas therein, a needle guide normally disposed adjacent the end of the needle to support the needle against lateral movement as it enters the container, means to mount the needle guide and needle for relative movement axially of the needle, means to carry the needle in an axially fixed position, means to move the container support toward the needle, said needle guide being mounted for movement in the direction of movement of the support and including abutment means to be engaged by a container on the support to be moved thereby, yieldable resilient means to urge the needle guide toward the support and a container thereon, said needle guide abutment means including shoulders cooperative with portions of a container on the support to center the container thereon to receive the needle in a predetermined place, said needle guide including a sleeve to receive the needle, said sleeve including a laterally flexible end portion adjacent the container.

3. Apparatus as set forth in claim 2, said sleeve being formed of plastic, and means to mount the sleeve in the guide for limited movement relatively thereto radially of the needle.

4. Apparatus as set forth in claim 2, said sleeve including a portion adjacent its other end to be engaged by said means to carry the needle when the charging member and container support are in their most proximate positions.

5. In apparatus for charging containers with gas, a frame, a container support mounted on the frame for vertical movement, a fixed cross head supported by the frame above the container support, gassing needle means carried by the cross head in a depending vertical position, drive means to raise the container support to cause containers thereon to receive the needle means, means in the cross head to receive gas under pressure to be passed into the needle means, a movable cross head carried by the frame above the containers on the support for vertical movement, guide means in the movable cross head to support the charging means laterally, first and second conduit means to pass gas from a pressure source to the needle means, a flow restricting orifice, a gas reservoir and a first valve in the first conduit means, a second valve in the second conduit means, and means operated by drive means for the container support to operate the first and second 7 to p Y valves in timed relation to open the first valve before the needle means enters a container and to open the second valve after the needle means enters a container.

6. In apparatus for charging valved containers with gas, a frame, a container support mounted on the frame for vertical movement, a fixed cross head supported by the frame above the container support, gassing needle means carried by the cross head in a depending vertical position, drive means to raise the container support to cause containers thereon to receive needle means, means in the cross head to receive gas under pressure to be passed into the needle means, a movable cross head carried by the frame above the containers on the support for vertical movement, guide means in the movable cross head to support the charging means laterally, container valve operating means carried by the movable cross head to open the container valve while the needle means enters the container, conduit means to pass gas from a pressure source to the needle means, a valve in the conduit means, and means operated by the drive means to open the valve in the conduit as the needle means enters the container and as the container valve operating means on the movable cross head opens the container valve, thereby to purge the container.

7. Apparatus as set forth in claim 6 including means to disable the container valve opening means after a predetermined interval.

8. Apparatus as set forth in claim 7, said drive means for the container support comprising a cam, said disabling V means for the container valve operating means comprising a portion on the cam to lower the container support for a short distance;

9. In apparatus for charging containers with gas, a frame, a pair of uprights supported by the frame, a container support slidably mounted on the uprights, cam means to raise the container support, drive means for the cam means, a fixed cross head carried by the uprights at their upper ends, a movable cross head slidably mounted on the cross head between the container support and the fixed cross head, resilient means to urge the movable cross head downwardly, charging needle means carried by the fixed cross head, container positioning and needle guiding means carried by the movable cross head, gas conduit means to connect a source of gas under pressure to the charging needle means, valve means in the conduit means, cam means movable with the drive means to operate the valve means, said drive means including an electric motor, means to energize the motor including a normally open starting switch, a normally open by-pass switch connected around the starting. switch, and cam means movable with the drive means to close the control switch while the container support is away from its loading position.

10. In a method for gas charging a closed container through a charging member adapted to be brought into communication with the inside of the container, the steps of establishing a first gas pressure value in the member no less than that to which the container is to be ultimately charged, thereby to establish gas flow from the member, bringing the member and container into charging relationship, subsequently raising the charging pressure in the member to a second value to increase substantially the gas flow into the container, and terminating the charging operation after a predetermined interval to establish an internal container pressure no greater than the first gas pressure value, by first reducing the charging pressure in the member to a value in the vicinity of the first value, and breaking the charging relationship between the container and the member.

11. The method as set forth in claim 10 in which the ultimate pressure to which the container is to be charged is approximately half of the rupturing pressure of the container and in which the second pressure value is slightly less than the rupturing pressure.

12. In a method for charging a closed container having a .quantity of liquid therein using a charging member adapted to be brought into communication with the inside of the container, the steps of establishing a first gas pressure value in the member no less than that to which the container is to be ultimately charged, thereby to establish gas flow from the member, bringing the member and container into charging relationship, causing the member to discharge into the liquid in the container and raising the gas pressure in the member to a second value substantially exceeding the first, thereby to discharge gas into the liquid at an increased velocity to establish agitation thereof, and terminating the charging operation as the internal pressure approaches the second value, by first reducing the charging pressure in the member to a value in the vicinity of the first value, and breaking the charging relationship between the container and the member.

13. The method as set forth in claim 12, in which the ultimate pressure to which the container is to be charged is approximately half of the rupturing pressure of the container, and in Which the second pressure value is slightly less than the rupturing pressure.

14. In a method of gas charging a pressure resistant container having a quantity of cream therein to be whipped by the gas and subsequently discharged from the container 'by the gas pressure, the container having adischarge valve operable by inwardly directed pressure and capable of receiving a gas charging member, the steps of causing a gas flow from the member by establishing a first pressure value therein no less than theultimate pressure to which the container is to be charged, bringing the container and charging member together to cause the member while discharging gas to enter the container through the valve to discharge the gas into the cream, moving the container and member in the opposite direction for a short distance to seat the valve'firmly'in the container, raising the gas pressure in the member to a second value slightly below the rupture point of the con- 12 tainer to discharge gas at a higher velocity intothe cream to establish agitation thereof and entraining of the: gas thereby, reducing the gas pressure in the member to the vicinity of the first value, and separating the member and the container.

15. In a method for gas charging a pressure resistant container partially filled with a liquid, said container having a dischargevalve operable by inwardly directed pressure and capable of receiving -a charging member, the steps of causing a gas flow through a charging member by establishing a pressure therein, bringing the container and member together to cause the member while discharging gas to enter the container through the valve to communicate first withthe space above the liquid and to open the valve, the discharging gas thereby displacing air from the container through the valve, causing the member to discharge the gas into liquid to be entrained thereby, moving the container and member relatively to one another to close the valve, introducing a predetermined further quantity of gas into the container through the member and separating the member and the container.

References Cited in'the file of this patent UNITED STATES PATENTS