US2364400A - Apparatus for filling - Google Patents

Description

5, 1944. R. J. STEWART Erm.' 2,364,400

APPARATUS FORFILLING Filed June g1, 1940 Patented Dec. 5, 1944l APPARATUS FOR FILLING Robert J. Stewart and Henry H. Franz, altimore, Md., assignors to Crown Cork & Seal Company, Baltimore, Md., a corporation of New York Application June 21, 1940, Serial No. 341,744

14 Claims.

This invention relates to apparatus for lling, and more particularly, to mechanisms for filling milk containers. The present application is a continuation in part of our application for Filling structure, Serial No. 215,680, filed June 24, 1938.

In machines heretofore used for lling milk containers, it has been the practice to provide a rotary reservoir having downwardly extending filling nozzles or heads. The bottles or other containers to be lled are conveyed to and positioned on suitable platforms below these filling heads and, as the reservoir revolves, each bottle is raised until its mouth engages a depending filling head. 'I'he engagement between the bottle and head is operative to open a valve structure usually built into the lling head, and the opening of the valve permits gravity iiow of milk from the reservoir into the bottle. The air -which would otherwise be trap ed in the bottle and prevent the free flow of milk is vented through an unobstructed vent tube generally extending vertically and centrally through the filling head with the upper end of the tube extending above the milk in the reservoir. Thus the air in the bottle is forced by the in-owing milk to pass through the vent and into the top of the reservoir which is at atmosphericV pressure.

It will be appreciated that with such a construction, usually termed a gravity filler, the speed with which a bottle may be filled is limited by reason of the fact that the iii-flowing milk must push the air trapped in the bottle upwardly through the vent. I

Another necessary element of this gravity lling equipment is the provision of a displacement member on the lower end portion of the air vent tube which is positioned within the neck of thebottle. This displacement member must be provided because during the lling cycle, the milk will flow into the bottle until it is lled and will then continue to flow upwardly in the air vent tube until the latter is lled to the same level as the surrounding liquid in thereservoir or tank. When the bottle has reached the end of the filling cycle and is moved downwardly from the filling head, thus permitting the filling valve to close, the milk in the open vent tube will ow downwardly into the bottle. The volume displaced by the displacement member in the bottle is just equal to the volume of liquid that has flowed into the vent. Therefore, when the bottle on the platform has been lowered away from the filling head until the displacement member has been wholly withdrawn from its neck, the liquid owing from the vent tube into the bottle neck will completely nu it to the desired level.

In other words, the volume of the displacement member must be equal to the capacity of the vent tube, plus the volumeof the air space to be purposely left in the mouth of the bottle,

above the milk, after the bottle has been filled to the desired level. If every bottle is to be filled accurately to the same level, the level of the liq uid in the reservoir must be controlled to a fine degree, because if the level varies to any extent, the volume of liquid that will ow into the vent tube in the filling process will vary, and as the displacement member always provides the same volume in the bottle that must be filled, any difference in volume of liquid which flows back out of the vent tube will be apparent in the level to which the bottle is finally filled. Therefore, with this displacement type of gravity filling head, an extremely accurate control of the liquid level in the reservoir must be maintained.

The limitation of the size of the displacement member and the diameter of the bore of the vent tube, in addition to requiring a fine adjustment of the level of the liquid in the reservoir, also restrict the quantity of liquidA that may be contained in the reservoir. The diameter of the vent tube bore must be large enough to permit a free flow of air therethrough. It is evident that the volume of liquid which will flow into the bore lduring the filling process is directly related to the diameter of the bore and the level to which the liquid will flow into the vent tube is governed by the level of liquid maintained in the reservoir. With the type of apparatus above described it has been necessary to maintain this level relatively low in order that a too large volume of liquid will not flow into the vent and thus require an unduly large displacement member.

It will be observed that by the above arrangement time is consumed in filling the space previously occupied by the displacementmember and there is'nothing to prevent the unsanitary dripping of milk from the filling heads.

In addition to the gravity flow milk filling machines discussed above, another type in general use includes a vacuum tank above the bottle platform and provided with iilling heads which are connected both to the vacuum tank and to a milk tank positioned at a point below the bottle platform, with a flow line angled to a point above the filling heads extending between the milk tank and the filling heads. By this arrangement, the positioning of a bottle in contact with a filling head causes a vacuum circuit to be closed between the vacuum tank and the milk tank so that milk will be drawn upwardly from the latter through the angled passage and into the bottle. When the bottle is moved downwardly, the vacuum line to the milk tank will be broken. This will cause the milk in the outlet portion of the angled flow line to flow downwardly into the bottle to fill the space previously filled by the I usual filling head diplacement member, while milk and foam already inthe filling head vent tube will be drawn upwardly into the vacuum tank.

The above method also has the disadvantage of requiring time to have the space occupied by the displacement member filled with milk during the final portion of the filling cycle. Also, there will be dripping of milk from the angled passage after a bottle is removed therefrom.

Other arrangements used to fill milk involve the use of an extremely high vacuum of the order of approximately fifteen inches of mercury, the principal idea of such. arrangements being to keep the milk isolated from air. The difficulty with such an arrangement is that unless the milk is to be prevented from increasing its bulk, due to the exertion of such a high vacuum upon its natural air content, a plurality of tanks must be provided, thereby greatly complicating the filling apparatus. Also, milk under such a high vacuum is in a rather unstable condition and readily tends to foam, particularly when it is sucked or drawn into a bottle and thereby impacts with a bottle surface. The use of such a high vacuum also causes difiiculty in releasing the bottles from the filling heads. In fact, a vacuum of only three or four inches of mercury will cause bottles to adhere to the filling heads.

In addition to the above disadvantages of the prior machines and their methods, there is another problem peculiar to the filling of milk which they have entirely failed to overcome. That is, when milk is owed into a bottle from a point above the bottle, it foams to a substantial extent and some time is required to displace this foam with solid milk. The prior machines and methods have approached this problem by flowing the milk as rapidly as possible with the idea that the more rapid the flow of the milk the more quickly the bottle will be filled with solid milk. This theory, while entirely logical, cornpletely overlooks the fact that the rapid flow of the milk, resulting in a sharpened impact with the bottle, induces a greater amount of foaming than would be the case if the milk is flowed at somewhat reduced velocity.

We have discovered that if the filling is so performed that the milk will flow into the bottle in an ample stream but at reduced velocity, less foaming will occur, and since less foam must therefore be removed before filling is completed, the time required for filling will be markedly reduced.

For example, the usual milk filler requires eight or nine seconds to fill a quart bottle with solid milk by following the prior system of flowing the milk as rapidly as possible into the bottle with no restriction on velocity. We have found that by fiowing the milk in a stream of the same cross-sectional area as previously used, but with less velocity, less foam is produced. As a result little or not time is required to remove foam, and the same bottle can be filled with solid milk in approximately six seconds.

The principal object of the present invention is the provision of a method and apparatus for rapidly filling milk containers in an entirely sanitary manner.

The method whereby the above object is obtained may be generally described as establishing within the milk reservoir and the containerY a vacuum having a measurement just slightly greater than the head of the milk in the reservoir. For example, if the milk has a head of twelve inches at the filling heads, a vacuum equal to eighteen inches of milk will be entirely sumcient; in fact, less vacuum is usually ample. The milk is then flowed from the reservoir into the container in a stream of the usual volume but with the stream impeded by a bame or a tortuous path so that it will flow with a velocity somewhat lower than that with which it would ordinarily flow under the same head with unrestricted passages.

A vacuum of twelve inches of milk corresponds to a vacuum of only one inch of mercury.

The present method, involving the use of a vacuum effect in the milk reservoir above the bottles, entirely prevents all dripping of milk or leakage from the reservoir at any point. In other words, at any point where dripping or leakage might occur, air is tending to enter the reservoir and milk obviously cannot-l escape. Furthermore, the use of such an arrangementwith an extremely low vacuum effect enables continuously open vent tubes of small bore to be used. thereby reducing the size of the vacuum pump required.

The ability to use vent tubes of small diameter is also due to the fact that the only function of the vent tubes is to draw surplus milk and foam up into the reservoir immediately the bottle is moved out of contact with the filling head. That is, in milk fillers of the gravity type discussed above, the milk which flowed into the vent tube was used to fill the space previously occupied in the bottle by the displacement member, and it was desirable to have the vent tube of large dlameter in order to enable this replacing flow to occur as quickly as possible. Since the vent tubes of our `invention do not have this function, they may be of smaller bore. Furthermore, the use of small vent tubes reduces the air velocity of air in the filling tank and decreases the possibility of milk being atomized and drawn to the vacuum pump.

The use of a vacuum in the milk reservoir to quickly draw surplus milk and foam up into the milk reservoir, for which only a very low vacuum is required, is to be distinguished from the prior use of a vacuum in a tank above the filling head for the purpose of lifting milk from a reservoir below the bottle. That4 is, in the prior construction, the degree of vacuum was gauged according to the distance which the milk had to be lifted from the reservoir below the bottle, whereas by our invention, the vacuum is merely for the purpose of quickly lifting surplus milk back into the reservoir above the bottle. It is also to be noted that the use of the vacuum effect in the present method has no purpose whatever in controlling the rate of filling a container, but is simply used to maintain a fixed head of milk, whereas the prior arrangements discussed immediately above which use the vacuum to lift the milk from a point below the bottle determine the rate of filling by the rate of vacuum. In other words, in such prior fillers the rate of vacuum was increased in order to more quickly lift the milk from a point below the bottle.

It has also previously been proposed to use milk filling machines including a milk reservoir above the bottles, with a vacuum condition within the reservoir. Also, the filling heads of these machines have been provided with vent tubes. However. these vent tubes were provided with valves adapted to be closed as soon as a bottle moved downwardly from the filling head. These prior arrangements, therefore, cannot function to immediately draw surplus milk through the vent tube up into the filling reservoir when the bottles move from the filling head due to the fact that the vent tube is then immediately closed. Because of this, any surplus milk moving up into the Vent tube simply remains there until a second bottle is placed under the filling head. The

usual practice is to have the vent tubes extending vertically toward the top wall of the filling tank with the result that milk moving from the vent tube is directed against such top wall, resulting in foaming and atomization, some of the atomized particles being drawn into the vacuum pump. By the present invention, each vent tube has its upper portion inclined toward the side of the filling tank at such an angle as to prevent splash and thereby atomization and also to reduce foam production in the filling reservoir.

The features of the present invention whereby foaming is reduced permits a filling tank of smaller size to be used. Prior milk filling machines have been provided with relatively large filling tanks, for example, with the usual fourteen head filling machine a filling tank of thirty-three gallons displacement is provided in order to accommodate the large volume of foam returned from the bottles and produced in the filling tank by the contact of the returned stream upon the top Wall of the filling tank. By the use of our invention 4it is found that a fllling tankof only twenty-seven gallons capacity need be provided with a fourteen head machine.

It is also to be noted that the reduction of foam Within the filling tank is highly desirable from the standpoint of sanitation, since foam within the filling tank represents a tremendous amount of air-exposed surface which results in aerating and thereby contaminating the pasteurized milk.

Another object of the present invention is to provide a milk filling apparatus of extreme simplicity and which includes a minimum number of parts.

It is to be noted that in milk handling equipment, simplicity is the ultimate design consideration, because less time is consumed in the operation of cleaning and sterilizing equipment that has few parts and is of simple construction. As'v sterilization may be performed several times in one day and, as every part of the dairy equipment that comes in contact with the milk must be so cleansed, the time required for cleaning has a marked bearing upon the cost of handling milk.

A still further object of the invention is to provideha readily removable deformable valve element of the type disclosed in the patent to Robert J. Stewart, for Filling apparatus, No. 2,127,892, issued August 23, 1938, and to further improve upon the structure disclosed in that patent.

Other objects and advantages will be apparent from the following specification and drawing, wherein- Figure 1 is a vertical section through the filling tank and a filling head and shows a bottle on its platform about to engage and open the filling valve, and

Figure 2 is an enlarged vertical section through a filling head showing the neck of a bottle in 3 filling position with the valve of the filling head in fully opened position.

The filling machine here disclosed has a liquid supply reservoir I0 mounted for rotary movement in any well known manner.' A cover II is provided which has a substantially air-tight engagement with the edges of the aperture I2 in the upper wall of the reservoir. Cover II`includes an apertured boss I3 which rotates with the cover II within a fitting I4 connected to a vacuum line I5 whereby a low pressure condition is established Within the upper portion of the reservoir I0 above the surface of the milk therein. Milk is delivered to the reservoir IU through any suitable pipe system including a tube I6 supported within the central and upper portion of the boss I3 and having a fioat valve I1 connected at its lower end so that flow of milk into the reservoir will be controlled by float I1 to maintain the reservoir filled to a predetermined point as indicated in Figure 1.

The reservoir III is provided with a series of circumferentially spaced depressions or pockets I8 including bottom walls I8a and inclined surfaces I8b. Each pocket has welded therein a collar or shell I9 forming a part of a filling head. Each pocket I8 andthe associated shell I9 thereby form a tube.

Each shell I9 is of generally cylindrical form and is provided with a straight bore 2I which-is bevelled at its upper edge as indicated at 22, The wall of each shell is reduced in thickness at its lower end as indicated at 23 to provide a downwardly facing shoulder 24. A substantially fiat washer 25 of known .type and formed of thin metal contacts with the shoulder 24 and extends outwardly to receive all otherwise drip into a bottle. A deformable valve element 26 is positioned upon the reduced portion 23 with its upper surface in contact with the collar 25. Valve element 26 is formed of resilient material such as rubber and includes a relatively thick walled neck portion 21 which surrounds the reduced portion 23 of shell I9 and contacts with the collar 25. Each valve element also includes a depending and inwardly extending thin walled bulbiform lower portion 28 which normally has its lower edge 3I seated upon a conical seat 32 formed at the lower end of the vent tube 33 as described in said Stewart Patent No. 2,127,892.

At the upper end of the bore through the neck portion 21, there is provided an annular ridge 3ft. By this arrangement, the bore of the neck portion does not have contact with the portion 23 of shell I9 over its entire area, but only at the extreme lower portion of the -bore and at the ridge 34. The upper surface of the neck portion 2'I is also provided with an upwardly facing shoulder 35 at a point spaced from the bore through the neck portion. This shoulder bears upon the under surface of the collar 25.

The provision of the ridges 34 and 35 on valve element 26 urges the lower edge of its neck bore toward firm engagement .with the surface 23 so that no milk can fiow between the valve element and surface 23 when the valve is flexed as shown in Figure 2.

Vent tube 33 is fitted within the bore 2I of shell I9, being centered within the shell by means of ribs 36 which are outwardly extended at their upper ends to provide inclined shoulders 31 to bear upon the bevelled surface 22 at the upper inner edge of shell I9.

` As is described in the said patent of Robert J. Stewart, the deformable valve element 26 will nor-l condensation which might mally be held seated upon the valve seat portion 32 of the corresponding vent tube 33, but when a bottle is raised to have its lip contact with the lower portion of the valve element as shown in Figure 2, this portion will be lifted from seat 32 so that milk may ilow downwardly into the bottle in an annular stream.

Each vent tube 33 is of relatively small diameter and has a correspondingly small bore 38 so as to reduce the cross sectional volume of the milk which may be drawn up into it. The lower end of the bore 38 is tapered as indicated at 39, this tapered portion extending into a restricted portion I of bore 33. Restriction 43 is preferably provided for the purpose of reducing the size of the aperture through which air may ilow when no bottle is beneath the head and also to further prevent dripping of milk from the vent tube.

A ange or washer Il is provided upon the tube 33 at such point that the under wall of the ange or washer will be spaced from the upper surface of the bottom wall I3a of the pocket I8 by a distance which would be not less than one-sixteenth of an inch so as not to be clogged by butterfat particles in buttermilk, the rate of flow being controlled by the spacing at this point The outer edge of the ilange element is preferably rounded in vertical cross section. The upper rounded edge of the flange deiines the inner wall of a converging annular mouth leading to the annular passage C--A-B between the other portions of the flange and opposed Walls of the pocket I8. It will be observed that the ribs 36 terminate at a point adjacent the downwardly inclined portion of the ilange 4 I By the above arrangement, the flange 4I comprises a baille or obstruction in the path of downwardly moving milk and, with the opposed walls I3a and I8b of the pocket I8, forms a tortuous passage for the milk. Movement of the milk through this passage naturally decreases its velocity by friction and turbulence. By having the restriction at the point A with a larger space below the same as at point B, turbulence is increased. It will therefore be observed that though the tortuous passage thus provided will deliver to the space B between the outer wall of the vent tube and the inner wall of the bore of shell I3 a supply of milk to till the capacity of that space,

such milk will move into the space at a reduced velocity, so that it will. drop with less force into the bottle. The portion of the tortuous passage between the under-surface of the bottom wall Isa of pocket Ill forms a horizontal course in the tortuous passage. This horizontal course, which naturally causes the stream to deviate from the vertical, increases turbulence in the stream.

As soon as the lip of a bottle is sealed against the portion 28, the air contained in the bottle will be drawn upwardly through the constantly open vent tube by reason of the low pressure area maintained above the liquid in the reservoir. As the bottle moves further and opens the valve, the liquid above the valve will ilow through the passage provided between the shell I! and the vent tube 33 under the influence of gravity. However, because of the fact that the milk must move through the tortuous passage C-A-B, its velocity will be decreased so that the milk will not flow downwardly at a speed entirely commensurate with its head. The liquid moving down through the filling head will strike the conical seat 32 of the vent tube and will be deflected toward the wall ot the bottle. This will prevent the mouth oi the vent tube 33 from being obstructed during the nlling process.

It will be noted that each pocket la and the associated shell Is form an outer tube element, while vent tube 33 forms an inner tube element, the opposed surfaces of the two tube elements deilnlng an annular passage.

When the bottle has been completely iilled, milk will flow up into the vent tube to the level of the body of liquid in the lling tank. The pressure acting on the surface of the liquid in the illling tank and that on the surface of the liquid in the vent tube being equal, the flow condition of liquid will momentarily be balanced.

After the bottle is completely filled and the above described static condition is obtained, the bottle platform will lower the bottle away from the filling head. Such static condition will be maintained until the bottle has been lowered so far that the seal between the bulbiform portion of the valve and the lip of the bottle is broken, at which moment the valve will already have been closed to further flow. Breaking of the seal between the bottle lip and the valve will permit atmospheric pressure to enter the neck of the bottle. It is to be noted that the vacuum maintained in the filling tank is preferably only of sufiicient degree to cause the milk in the vent tube to be drawn up into the reservoir or, in other words, pushed up into the reservoir by the atmospheric pressure acting through the lower end of the vent tube.

It will be noted that the upper portion l5 of vent tube 33 is inclined outwardly to lie at an obtuse angle to the side wall of reservoir I0. Because of this, milk projected from the upper end of tube 33 will strike the side wall of the reservoir at an obtuse angle and will ow quietly down the reservoir wall, thereby preventing splash and atomization, and assisting in holding foam to a minimum.

When the bottle has been completely lowered away from the valve, the vent tube will, of course, be open to atmosphere and maintained open until another bottle moves into illling position beneath that Yfilling head. The restriction 40 in the vent tube'insures against the dripping from the vent tube of any liquid that might cling to the wall of the bore of the tube and also reduces the volume of the air stream which may pass through it.

It will be observed that the present method, eliminating the necessity of a. large displacement member at the bottom of the vent tube, provides faster filling because it is not necessary for any liquid to move downwardly through the vent tube to lill the space previously occupied by a displacement member.

As a bottle moves downwardly from the position shown in Figure 2 to permit the valve 26 to close, milk will simultaneously ll the space in the mouth of the bottle occupied by the lower end of the vent tube. In this manner, full lling of the bottle is assured.

As has been stated above, the degree of vacuum or low pressure maintained through the line I5 is preferably relatively low, being only suiiicient to draw up into the filling tank the milk which flows up into the vent tube. It is found that the vacuum will be ample if it is only 50% higher than the head of the milk in the lling tank. For example, if the milk is maintained to a depth of twelve inches in the lling tank and thereby has a head of twelve inches at the nlling valve, a vacuum equal to eighteen inches of milk will beY entirely sumcient. In tact. in most installavtortuous passage for flow of the milk through each filling head further reduces the velocity of iiow of the milk without restricting the size of the ow passage. Provision of an extremely low vacuum has the further advantage of preventing the high percentage of air normally in milk from being expanded. Such expansion tends to create foaming, particularly when the milk lcontacts with the bottle during filling or when it moves upwardly through the vent tube 33 into contact with the filling tank wall.

It is found that by reducing the foaming of the milk as occurs with our method, the necessity Aof a large filling tank is obviated. Most prior filling machines are equipped with a relatively large filling tank, primarily to accommodate the foam which forms in the tank during the filling process. Since the present method inhibits foaming toa substantial degree, it is not necessary to provide as large a filling tank. For example, prior machines provided with filling tanks including fourteen filling heads are normally of a capacity of thirty-three gallons while by our method a fourteen head machine filling tank need only be of twenty-seven gallons capacity. The reduction of foam within the filling tank obviousiy is a great advantage from the standpoint of' sanitation because foam tremendously increases the surface area exposed to air and contamination.

Because of the fact that the present method reduces foaming to a minimum, it is possible to fill a bottle much more rapidly with solid milk. As has heretofore been stated, prior filling methods, using a rapid flow of milk-into'the bottle, have resulted in foaming and a substantial proportion of the filling time has been occupied in withdrawing foam from the bottle and replacing the same with milk, the time required for a quart bottle being from eight to nine seconds. Because the present method inhibits foaming, it insures that the bottle will vlll rapidly with solid milk, a quart bottle usually requiring about six seconds for filling. The ability to fill faster with solid milk by the present method is due entirely to the fact that we fiow the usual volume of milk but at a lower velocity, this low velocity being due to the fact that the milk stream, while of normal cross' section, must move about a baille, 0r in a tortuous path.

It may be stated that because of the lowered velocity of the milk flowing into the bottle by the present method such small foam bubbles as may form around the lower portion of the vent tube 33 and between the extreme lower end of the'vent tube and the mouth of the bottle can rise quickly into the tank through the incoming stream of milk. Removal of foam has been extremely diflicult with prior methods and machines because of the high velocity and head of the descending milk.

The bore of the vent tube which may be used with the present method is extremely small. Heretofore it has been necessary to provide a large vent tube of the order of nine-sixteenths of an inch in diameter to quickly draw foam into the filling tank from the bottle. Reducing the size of the vent tube to approximately sevensixteenths of an inch at its smallest portion, as may be done with the present method, particularly with the vacuum system, has the material advantage of enabling the vacuum pump to be of small capacity. Also, the smaller the diameter of the vent tube, the smaller the quantity of milk which will be in the tube after the bottle is filled and the less possibility there is of such milk foaming when it contacts with the filling reservoir wall. Vent tubes of reduced size also reduce the air velocity in thel upper portion of the filling tank, thereby decreasing the tendency toward carrying atomized milk from the filling tank toward the vacuum pump.

bubbles from this area Since each vent tube is open to atmosphere during the short interval between the removal and delivery of bottles, it is desirable to reduce fiow through the same as much as possible. The use of constantly open vent tubes in itself has numerous advantages over prior machines because such tubes eliminate valves and insure that surplus milk will be instantly drawn upwardly into the filling tank. The use of a low pressure condition'in the filling tank also has inherent advantages serving to give faster and more accurate filling, as Well as prevent the filling of imperfect bottles.

It will be observed that the use of a very slight vacuum of the,degree defined above permits the present machine to operate with only a sin-gie tank for the milk, whereas machines operating under a higher vacuum must be provided with a series of reservoirs in order to avoid exerting too high a vacuum directly upon the surface of a body of milk. Our use of a constantly open vent tube likewise eliminates the necessity of a plurality of tanks at different pressures, as well as eliminating a series of valves as pointed out above.

The terminology used in the specification is for the purpose of description and not of limitation, the scope of the invention being indicated by the claims.

Furthermore, while the embodiment of the invention specifically described herein refers to the filling of milk it will be observed that at least a number of features of the invention are entirely applicable to the handling of other liquids.

We claim:

1. In a filling machine, a reservoir, means to maintain a body of liquid in the reservoir and an uninterrupted low pressure condition above the surface of such liquid, a filling head communica'ting with the liquid containing portion of the reservoir, said filling head including a valve to control the flow of liquid from the reservoir, and a continuously open vent tube adapted to communicate at its lower end with a container positioned beneath the filling head, the upper end of the .tube being continually open to the upper portion of the reservoir, the bore of said vent tube including a restriction to prevent dripping.

2. In a rotary filling machine, a reservoir having a centrally apertured cover, means to maintaina body of liquid-in the reservoir including a liquid supply pipe, and means to maintain a low pressure condition above the surface of such liquid including a suction head concentric with said pipe and disposed vertically through said lcentrally apertured cover into said reservoir, a

lllng head communicating with the liquid containing portion of the reservoir, said iling head including a shell, a resilient valve adapted to be carried by said shell to control the now of liquid from the reservoir, and an open vent tube adapted to communicate at its lower end with a contalner positioned beneath the filling head, the upper end of the tube being continually open to the upper portion of the reservoir, the lower end of said vent tube being enlarged to provide a seat for said resilient valve and being also provided with bottle centering means, and the bore of said vent tube being reduced adjacent its lowermost end.

3. In a illling machine, a lling reservoir including a bottom wall and a vertically extending side wall, a illling head iny said bottom wall including an outlet flow valve, a vent tube in said filling head, said vent tube extending upwardly through said iilling head and having at least its upper portion inclined toward the side wall of said llng reservoir so as to project liquid moving from the tube against said side wall at an obtuse angle with respect to said side wall.

4. In a milk lling machine, a milk reservoir, a iilling head including a'valve to control downward flow of milk to a container positioned beneath the filling head, the filling head including concentric inner and outer tubes positioned to define between them an annular milk :dow and foam return passage, said inner tube serving as a vent tube, one of said tubes having a radially extending baffie thereon within said passage and spaced above its lower end and projecting into the annular passage, the other of said tubes being so formed adjacent said baille that, in vertical section, its annular passage surface will substantially conform to the vertical sectional outline of said baille to define a tortuous path including a substantially horizontal course which path will produce turbulence in and exert friction upon the milk to reduce its velocity and enable such foam as is created in the container to readily rise through the descending milk stream.

5. In a milk filling machine, a milk reservoir, a filling head including a valve to control downward flow of milk to a container positioned beneath the iillng head, the illling head including concentric inner and outer tubes positioned to denne between them an annular milk flow and foam return passage, said inner tube serving as a vent tube, and having a radially projecting baille on its outer surface within said passage' and spaced above its lower end, the inner surface of said outer tube being enlarged in diameter adjacent and opposite said radially projecting baille so that such portion of the inner surface of the outer tube will substantially conform to but be spaced from said radial baille to define a tortuous path including a substantially horizontal course which will produce turbulence in and exert friction upon the milk to reduce its velocity and enable such foam as is created in the container to readily rise through the descending milk stream.

6. In a milk iilling machine, a structure of the character described in claim 4 wherein the space between said inner tube and said outer tube is more restricted at one portion along said baille than at another portion along said baille.

7. In a milk nlling machine, a structure of the character described in claim 4, wherein the space between the lower surface of said radial baille on said inner tube and the opposed conforming surface of said outer tube is less than at other opposed portions of said tubes.

8. In a milk nlling machine, a structure of the character described in claim 5 wherein the space between said inner tube and said outer tube is more restricted at one portion along said baille than at another portion along said baille.

9. In a milk filling machine. a structure of the character described in'claim 5, wherein the space between the lower surface of said radial baille on said inner tube and the opposed conforming surface of said outer tube is less than at other opposed portions of said tubes.

10. In a milk filling machine, the combination with a structure of the character described in claim 4, of means to maintain a vacuuml condition in the milk reservoir suillcient to draw surplus milk upwardly through said inner tube.

1l. In a milk filling machine, the combination with a structure of the character described in claim 5, of means to maintain a vacuum condition in the milk reservoir suicient to draw surplus milk upwardly through said inner tube.

12. In a milk filling machine, a milk reservoir, a iilling head including a valve to control downward flow of milk to a container positioned beneath the illling head, the iilling head including concentric inner and outer tubes positioned to respectively define the inner and outer surfaces of an annular milk flow and foam return passage, said outer tube including a circular wall of relatively large diameter at its upper end, a substantially horizontal and annular wall at the lower end of said iirst-named wall portion, and a vertical circular wall of reduced diameter extending downwardly from the inner edge of said annular horizontal wall, said inner tube having a radially projecting flange positioned within said large-diametered circular wall, the lower surface of said flange being spaced above said horizontal wall and its diameter being greater than the diameter of said vertical reduced-diameter circular wall so as to define a tortuous path adjacent said flange which will produce turbulence in and exert friction upon the milk to reduce its velocity and enable such foam as is created in the container to readily rise through the descending milk stream.

13. In a milk filling machine, a structure of the character described in claim 12 wherein the space between said inner tube and said outer tube is more restricted at one portion along said ilange than at another portion along said flange.

14. In a milk filling machine, a structure of the character described in claim 12 wherein the space between the lower surface of said iiange on the inner tube and said horizontal surface of said outer tube is more restricted than at other opposed portions of said tubes.

ROBERT J. STEWART. HENRY H. FRANZ.

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