US 3308981 A
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Description (OCR text may contain errors)
Mamb 1967 A. J. STARR ETAL VENTING CLOSURE FOR CDNTAINERS Filed Feb. 26, 1965 BY W ATTORNEY m f a a m a m m o 1 7 \smfrm wm w/ w? PUT a W L A aw d l\1. W E W: w T5 H mm l 6 m2 0 a a u u 9/: flu w 2 f W l mu. L We a/ a x m w W m 1. m 1 i l M gi l 4v M flzflfiv h w r 4 K t i i United States Patent 3,308,981 VENTING CLOSURE FOR CONTAINERS Anthony J. Starr, Wilmington, and Reese 1. Savage, Jr., Newark, Deh, assignors to Container Corporation of America, Chicago, Ill., a corporation of Delaware Filed Feb. 26, 1965, Ser. No. 435,468 6 Claims. ((31. 215-56) This invention relates to containers and more particu larly to the provision of a completely reliable venting closure capable of permitting the escape of gas from the container but not the fluid contents thereof.
It is now common practice to transport valuable fluids and chemicals which are corrosive or easily contaminated in large drums and containers made of thermoplastic materials which are chemically inert. While these materials, such as for example polyethylene, are relatively soft and deformable, they are flexible, strong and practically unbreakable. These thermoplastic containers or drums are usually provided with one or more openings for use in filling and emptying the container. These openings are usually defined by flanges which are often provided with an exterior thread to accommodate a closure cap made of a suitable thermoplastic material, such as polyethylene, and are capable of effectively sealing the dangerous contents of the containers against leakage or spillage during handling.
It happens however, that certain of the compounds shipped in these thermoplastic containers or drums, such as ethyl chloroformate, sodium hypochlorite, hydrochloric acid, and hydrogen peroxide, are gas generating compounds, and will build up in a container gas pressures of one half pound per square inch and greater over a period of time. Due to the inherently dangerous nature of such compounds, it is necessary that such pressures be relieved without loss in the effectiveness of the seal provided by the closure'cap so that the compound itself will not escape from the container. On the other hand, there is the situation in which a compound is packed under relatively high heat conditions and shipped to a destination which is of such low temperature that a partial vacuum is created in the container. When this occurs it is sometimes necessary that the vacuum be eliminated before the contents of the container can be safely withdrawn.
We are aware that there has heretofore been devised a sealing member having a cup-shaped configuration and which is forceably inserted into a flange of a container such as above indicated to form a liquid tight seal with the inner walls of the flange. This prior sealing member comprises a generally horizontal flange from which a frusto-conical body portion depends having inwardly converging walls in th downward direction. The force fit causes the upper wall of the body portion to positively form a seal with the inner wall of the flange of the container while the remainder of the body portion tapers away from the container flange. A closure cap is then inserted over the sealing member and forces the flanges of the member and container into engagement with one another to further increase the force fit.
Gas in the container under pressure forces the sealing member away from the container flange wall, thus permitting escape of the gas between the flanges. Conversely, a vacuum in the container will cause gas to enter between the flanges and the sealing member and container flange wall. This is accomplished by the vacuum exerting a downward force on the bottom of the sealing member, thus affecting a straightening and moving away from the wall of the member from the flange.
While the above-described sealing member was a step forward in the solution to the problem which confronted the art, it was not entirely satisfactory due principally to the fact that it is very difiicult in actual practice to manu- 3.3%,981 Patented Mar. 14, 1967 facture sealing members of this type and container flanges of the type which are employed in containers of the indicated type, with constant exactitude as to insur that all sealing members will operate efliciently to perform their intended purpose on the usual run of container flanges.
It is accordingly the primary object of this invention to provide a new and improved cap-like closure which is capable of being connected to the flange of any one of a large number of polyethylene containers to form an effective liquid tight seal on such flange, and yet which is able to vent to prevent the formation of extraordinary gas pressures in the container associated with such flange without destroying the effectiveness of the liquid seal.
It is another object of the present invention to provide a sealing member which will effectively seal a container, 'but yet permit escape or entry of gases to the container despite variations in sealing member size over a wide range of dimensions.
It is a further object of the present invention to provide a sealing member, the etfectiveness of which is substantially independent of the tightness of the seal.
\Vith these and other objects in View, the present invention contemplates a cup-shaped sealing member having a frusto-conical body portion with an upwardly and outwardly extending wall terminating in a flange. The interior of the member is provided with ri'bs which extend up the wall and over the flange. In use, the sealing member is inserted in a container flange and is dimensioned to form a force-fit with the flange. A cap is screwed on the container engaging the ribs and forcing the flange wall of the sealing member against the upper and inner parts of the container flange, respectively. As a result of this construction, gas can enter or exit from the container by convenient passageways formed by flexing the mor pliable material between the ribs away from the container flange.
For a better understanding of the invention, as well as the novel features thereof, reference is made to the following description which should be read in connection with the accompanying drawings, in which:
FIG. 1 is a central vertical sectional View of the upper end of a container provided with a closure embodying the invention and showing the relation of th closure parts when normal conditions exist in the container;
FIG. 2 is a similar view on a reduced, partly diagrammatic scale showing the condition of the closure parts when a small, or harmless gas pressure exists in the container;
FIG. 3 is a view similar to FIG. 2 showing the manner in which the closure vents when the gas pressure in the container is too high;
FIG. 4 is a view similar to FIGS. 2 and 3 showing the condition of the closure parts when a partial vacuum exists in the container;
FIG. 5 is a central vertical section of an inner sealing member forming part of the closure; and
FIG. 6 is a section taken along line 66 of FIG. 5.
In the drawings, the numeral 10 designates generally a container made of any suitable elas-tomeric material of a chemically inert nature, such as polyethylene. The outlet opening of the container is defined by a flange 11 also molded of a chemically inert plastic material, preferably polyethylene because it is soft and flexible, but yet strong. The flange 11 may be integrally molded to the material of the container body 10, or may be molded separately therefrom and subsequently attached to the container body in any suitable manner known to the art. The exterior of the cylindrical body or wall constituting the flange 11, as shown, is provided with coupling means in the form of a suitable thread 12 of the buttress type. It will be understood however, that the thread 12 may be of any other suitable type, such as, a regular 60 V flange 11 is a straight, smooth, cylindrical surface, at
least in the upper portion of the flange, and that at the top of such flange there is provided an annular seating surface 14 disposed substantially at right angles to the vertical, andof a width substantially equal to the thickness of the flange body or wall between such interior surface 13 and the root line of thread 12. It will be further notedthat the start of the thread 12 is adjacent to said seating surface 14.
Seated on the annular surface 14 is an outwardly projecting annular flange 21 provided on the top of a cupshaped sealing member designated generally by the numeral 20 and also constituted of polyethylene; such flange being disposed at substantially right angles to the vertical axis of such member. The sealing member 20 includes a body portion 22 which is generally circular in horizontalcross-section and converges downwardly and inwardly from the flange 21 so that it has a frusto-conicalconfiguration. Body portion 22 of member 20 comprises an outer wall 24 of uniform thickness. Spaced ribs 25 are uniformally positioned about the interior of wall 24 (FIGS. and 6) and extend from the bottom 26 of the member 20 up the wall 24 and over the top of flange 21.
The bottom wall 26 and side wall 24 are advantageously made the same thickness. The ribs 25 are preferably the same thickness as the walls 24 and 26'. Approximately the distance up the inside of wall 24, the inner edge portions 27 of the ribs .25 extend vertically upward to a point above the flange 21, and the top edges 28 of the rib portions 29 over the flange ,21 extend outwardly at right angles from the upper ends of such inner edge portions 27. Typical dimensions of a sealing member may be one inch in vertical height having a wall .030 inch thick with a rib .030 inch thick, so that the combined thickness of the ribbed wall is .060 inch. At a point on the inside of tapered wall 24- about inch from the .tOp edge, the inner edge portions or faces 27 of the ribs 25 continue upward at 90 to the top where they connect with the upper edges 28 of the top offset rib portions 29. The
effect is to progressively thicken the upper portion of rib cross-section within the sealing member so that the top end thereof has a thickness of .084 inch.- The thickness of the rib portions 29 directly overlying the flange 21 however is about .030 inch, the same as the thickness of the flange 21.
They material for the sealing member is a soft flexible polyethylene offering excellent chemical resistance to corrosive'materials while affording the necessary resilience for use to permit the escape of gases. The wall crosssectional values have been carefully selected to provide firm but yet functional walls under conditions of use.
The upper end of the wall 24 just below flange 21 has .an exterior diameter which is larger than the interior diameter ofthe container flange 11 into which it will be inserted. As a result, the sealing member when inserted :shape shown in FIG. 1. The force-fit due to the disparity in the diameters of the sealing member and flange results in a pressure tight seal. In practice, it is intended that such seal around the inside of the top edge portion of the flange 11 extend downward for approximately g of an inch. Flange 11 and sealing member 20 should be substantially smooth forsaid of aii'inch in order to assure a good seal. However, good seals are also formed with irregular surfaces. The walls of the flange and sealing member below such sealing area do not have to be smooth'but can be made with rough surfaces. It is of course understood that the degree of sealing can be varied by changing the dimensions of the sealing member,
into the flange will be compressed and will assume the 4i and/ or, the container flange 11 in order to arrive at a tighter or looser force-fit.
The associated closure cap'is indicated generally by the reference numeral 30 and like flange 11 and sealing member 20 may be made of relatively soft, deformable plastic material, such as polyethylene. The cap 30 comprises an outer cylindrical wall 31 provided with an internal thread 32 which "complements the threadli; formed on the flange 11. Above the upper terminal end of the thread 32 is a concave groove 33 which overhangs the flange 11 and receives flange 21 and rib portions 29 of sealing member 20 when the cap 30 is screwed into position on the flange- The inner. side of the wall of groove 33 merges smoothly into the upper end. of the outer in wardly inclined wall 34 of a tapered downwardly extend-' :ing conical member 35. The configuration of the inclined annular wall formed by the combination of the outer Wall 34 of member 35 and the inner sidewall of groove 33 is such that as the cap 30 is screwed into fully closed position on the flange 11, such annular wall will come into engagement with the innerperipheral edge'36 formed by the junctures of the upper edges'28' of the rib portions29 with the upper ends of the inner faces 27 of the ribs 25 of the sealing member 20, and bear against the same with I suflicient pressure to cause the seal formed by flange 21 and wall 24 with the flange seating surface 14 and the interior flange surface 13, respectively, to withstand a given gas pressure in the container 10.
It will be understood from the foregoing description of the parts, that when thesealing member 20 and the closure cap 30 are assembled on the flange 11,the parts will have the relation shown in FIG. 1. In such relation, the upper portion of wall 24 will be pressed in sealing engagement against the flange interior wall 13, and the flange 21 will be seated in sealing engagement on the flange surface 14. By designing the sealing member 20 and closure cap 30 properly, the seal thus formed will be liquid tight and will be gas tight for a given gas pressure within the container. In FIG. '1 the conditions of the parts are shown when there is little or no gas pressure in the container and the sealing member 20 and closure cap 30 function solely as a liquid seal. When there is a small gas pressure in the container, below that wlu'ch the parts are designed to relieve, as is indicated by the arrows 4i) in FIG. 2, the sealing action of the member 20 and cap will not be rendered less eflective, but will in fact become enhanced. This is believed to be due to the fact that the pressure of the gas on the relatively large area of the bottom 26 of the sealing member, will raise the same slightly, while the cap 30 maintains the upper edge of the sealing member seated on the flange seat 14, with the result that more of wall 24 will come into sealing engage-- ment with the interiorsurface 13 and thus increase. the affective area of the seal.
However, when the gas pressure in the container rises above that which the parts were designed to maintain, as
indicated by the longer arrows '41 in FIG. 3 of the drawings, such pressure, even though acting on the bottom 26 tending to increase the seal, will be greater than the transverse sealing force which the wall 24 is able to, apply to the flange. surface 13. The result is that the portions of the wall 24 betweenthe ribs 25 will be forced inwardly away from surface 13, and the corresponding portions of the flange 21 between the portions 29 of the ribs 25 will be deflected upwardly away from flange surface 14 sufficiently to permit the gas to leak up between wall 24 and surface .13 and around the top, of flange 11 between flange 21 and surface .14. The gas thus rescaled leaks through the sealing member, certain relationships should be kept in mind. The ribs should advantageously be at least the same thickness as the bottom wall. This is to prevent too rapid a deformation of the sealing member under pressure which will destroy the seal, for example, when the container is toppled over. Moreover, to properly maintain the seal, the depth of the sealing member should advantageously be about 1 and /2 times the diameter at the top to permit deformation without destroying the seal. The thin sections of wall 24 and intermediate ribs 25 should be approximately 1 and /2 times the width of the ribs to provide a flexible side wall which can be deformed without creasing.
FIG. 4 of the drawings illustrates what occurs when a substantial vacuum is created in the container, such as might occur for example if the contents of the container are loaded under high temperature conditions and the container has been delivered to a destination where very low temperatures prevail. As a result of the Vacuum, the bottom 26 will be bowed downwardly and the sealing member 20 drawn into the flange 11, thus breaking the sealing relation of the wall 24 and flange 21 of such member with the interior surface 13 and seating surface 14 of the flange 11, respectively. This permits the atmosphere to leak through the threads 12 and 32 into the container, as is indicated by the arrows 43 in FIG. 4, until suitable pressure conditions have been restored in the container.
Referring again to FIG. 1, the vertically extending portions of ribs 25 contact the inner annular wall of cap 30. Cap 30 pushes the top parts 29 of ribs 25 outwardly urging wall 24 into contact with flange 11 thus increasing the seal. By having the ribs 25 continued uniformly upwardly to the top of wall 24 without extending vertically upward, there is less likelihood that tightening of cap 30 might force the sealing member 20 downwardly into container 10.
By proper variation of the dimensions of container flange 11 and sealing member 20 together with proper tightening of cap 30 the degree of force fit can be adjusted to retain liquid seals at various static head pressures corresponding to the pressure of the container contents when the container is lying on its side. Since it is normal for cylindrical shipping containers of the indicated type to be laid on their side, tilted or otherwise moved around during shipping, it is necessary that the static head pressure be considered when designing a sealing member.
It has been found that the contents of a five gallon container will normaly exhibit a pressure between .35 to .40 pound per square inch. A sealing member should include a safety factor and a seal which will break at 1 and A1 to 1 and /2 pounds per square inch is recommended for the above head pressures. It has been found that variation of the sealing member and flange dimensions alone will permit seals in the range of 2 to pounds per square inch.
While I have hereinabove described and illustrated in the accompanying drawings, a preferred embodiment of my invention, it will be apparent to those skilled in the art that modifications and changes may be made in such embodiment without departing from the spirit of the invention, or the scope of the appended claims.
What is claimed is:
1. In a container structure, a tubular flange defining an opening in the container and constituted of flexible elastomeric material and having a seating surface at its upper end, a cup-shaped sealing member constituted of flexible elastomeric material and having at its upper end an outwardly extending flange seated on said tubular flange seating surface to support said member in depending relationship within said tubular flange, the body of said sealing member being of tubular configuration with an inner and outer side wall and a bottom wall, said outer wall being constituted of a continuous layer of elastomeric material, and said inner side wall being constituted of spaced ribs projecting inwardly from and extending up the outer wall and over the outwardly extending flange, said outer wall at its upper portion bearing against the interior surface of said tubular flange with sufficient pressure to provide a gas tight and liquid tight seal, a closure cap constituted of elastomeric material and having an outer depending wall coupled to said tubular flange, said closure cap having an inwardly tapered wall portion engageable with the inner peripheral upper edges of the spaced ribs on said sealing member to normally hold such flange seated in sealing relation on said tubular flange seating surface, and the exterior surface of the lower portion of said sealing member being spaced from said interior surface of the tubular flange to permit gas of high pressure to enter between said body and said interior surface and flex the portions of said outer wall of the body between the ribs away from the interior surface and the seating surface of said flange thereby permitting the gas to escape past the upper portion of the sealing member.
2. A sealing member for use in cooperation with an elastomeric tubular flange defining an opening in a container and having a seating surface on its upper end, and an elastomeric cap having an outer depending wall coupled to such tubular flange and an inwardly tapered wall portion, said sealing member being cup-shaped and constituted of flexible elastomeric material, said sealing member being provided at its upper end with an outwardly extending flange seatable on the tubular flange seating surface to support said member in depending relationship within said tubular flange, and the body of said sealing member being of tubular configuration with an inner and outer side wall and a bottom wall, said outer wall being constituted of a continuous layer of elastomeric material, and said inner wall being constituted of spaced ribs projecting inwardly from and extending up the outer wall and over the outwardly extending flange, said outer wall at its upper portion being capable of bearing against the interior surface of said tubular flange with sufiicient pressure to provide a gas-tight, liquid-tight seal, the inner peripheral upper edges of the spaced ribs on said sealing member being engageable with the tapered wall portion of the cap to hold the flange seated in sealing relation on said flange seating surface, the exterior surface of the lower portion of the body of said sealing member being configured to be in spaced relation to the interior surface of the tubular flange to permit gas to enter between said body and said interior surface and flex the portions of said outer wall of the body between the ribs away from the interior surface and seating surface of the flange to permit gas to escape past the upper portion of the sealing member.
3. A sealing member according to cliam 2, in which the exterior diameter of said body above a point substantially spaced from the upper end thereof is equal to the interior diameter of said tubular flange so that said tubular body above such pointis deformed from its normal configuration by said tubular flange.
4. A sealing member according to claim 2, in which said ribs are of substantially a constant thickness and are parallel to the inner wall of the body for the major portion of their length up to a point approximately A; the distance up the inner wall, whereupon said ribs then extend vertically upward.
5. A sealing member according to claim 2, in which the ribs are at least the same thickness as the bottom wall of the body portion.
6. A sealing member according to claim 2, in which the spacing between the ribs is at least 1 and /2 times the width of the ribs.
No references cited.
THERON E. CONDON, Primary Examiner. J. B. MARBERT, Assistant Examiner.