Valve assembly for controlling fluid ingress and egress from a transportable container which stores and distributes liquid under pressure

A valve assembly has (1) a riser pipe including a valve cup housing and portals blockable, and (2) a central tower which communicates with blockable pathways that pass both liquid and gas, and (3) a bi-directional valve member which controls separation of gas and liquid and directional flow in the chamber. A retainer assembly is provided on the outer peripheral surface of the valve cup so as to facilitate insertion of the valve cup into the container but so as to prevent the unintended removal of the valve cup from the container while still permitting selective valve cup removal when it is desired to do so. The retainer assembly preferably includes a protrusion and a pair of centering skids spaced about the outer periphery of the valve cup. The protrusion includes a radially tapered, vertical extending detent portion and a radially tapered, circumferentially extending ramp portion. The centering skids taper radially inwardly from vertically central portions thereof to the vertical end portions thereof. Upon simultaneous twisting and tilting of the valve cup relative to an annular member on the container such as the shoulder of a stub, the centering skids engage the annular member so as to take up the clearance between the valve cup and the annular member, and the protrusion ramps onto the annular member in a self-threading manner so as to circumferentially distort the valve cup and to permit the valve cup to be turned out of the container.

BACKGROUND OF THE INVENTION
 The invention relates to valve arrangements or valve assemblies and, in
 particular, relates to valve assemblies for transportable containers of
 the type serving to store and distribute a liquid under pressure from a
 propellant gas. The liquid to be stored and dispensed could comprise a
 beverage, a concentrate, a plant protection agent, or virtually any other
 transportable liquid.
 The typical valve assembly of the above-mentioned type comprises (1) a
 ring-shaped stub secured in an upper opening of a container such as a
 barrel; (2) a valve housing; (3) a riser pipe arranged co-axially with an
 upper reception area in the valve housing such that the riser pipe and
 outlet valve can be displaced axially, against the biasing force of
 springs mounted within and about the valve housing, from an upper closed
 valve position to a lower open valve position; and (4) retaining parts
 which hold all parts in position within the stub. In previously-known
 valve assemblies of this type, the valve assembly can be readily
 disassembled before the gas pressure in the container has been fully
 relieved. Residual gas pressure in the container can force the valve
 components out of the container opening at high velocities with
 substantial risk to personnel and/or surroundings.
 The problem of unauthorized disconnection of a pressurized container is
 addressed and at least partially solved in U.S. Pat. No. 5,242,092 to Riis
 et al. (the Riis patent). The valve assembly disclosed in the Riis patent
 includes, in addition to the stub, the riser pipe, valves, and springs, an
 obliquely and downwardly protruding finger provided on the lower free end
 of the riser pipe. The finger is spaced from the top of the riser pipe and
 cooperates with the remainder of the riser pipe such that the valve can
 only be dismounted completely when the riser pipe is in or in the vicinity
 of its bottommost position. Since pressure within the container forces the
 riser pipe upwardly and the finger therefore can be pushed into its lower
 position only in the absence of significant pressure, within the
 container, the finger functions to prevent damage which might occur if
 unauthorized persons were to attempt to disconnect the valve before the
 gas pressure in the container has been completely relieved.
 The valve assembly disclosed in the Riis patent, though solving at least
 one of the problems exhibited by most valve assemblies, does not solve
 other problems associated with conventional valve assemblies. For
 instance, it cannot relieve excessive gas pressures within the container
 which may be generated when the container is subjected to external forces
 such as excessive shaking or other mechanical agitation or fire or other
 thermal agitation. The valve assembly disclosed in the Riis patent and
 other, traditional valve assemblies are designed only to keep the contents
 within the container, not to regulate the pressure within the container.
 Hence, traditional valve assemblies cannot prevent gas pressures within
 the container from reaching or even exceeding explosive levels in the
 presence of external agitation forces. Even if these external forces are
 less severe such that gas pressures within the container do not reach
 explosive levels, the higher-than desired pressure within the container
 still may render the contents dangerous to handle when making connection
 to dispensing equipment.
 Another problem associated with previously-known valve assemblies is the
 problem of unintended and premature liquid escape during valve coupling.
 Presently-available valve assemblies are designed to cooperate with a
 coupling head which can be fixed in the valve or on the stub to form a
 sealed coupling. The coupling head, such as that manufactured by Perlick
 under the model number MK-1, connects the valve with a source of
 pressurized gas and with a liquid dispenser such as tapper. When the
 coupling head is seated and activated, an axially displaceable spindle is
 forced downwardly, setting-in-motion a two stage valve opening sequence.
 First the spindle comes in contact with the liquid valve plug, forcing it
 downwardly against a spring within the riser pipe, thereby opening the
 liquid passage. The spindle continues downwardly while making contact with
 the riser pipe itself, forcing the riser pipe downwardly against a second
 spring so that the riser pipe moves downwardly opening the gas passage,
 thereby completing the sequence and theoretically dispensing liquid only
 after the coupling head has been sealed and gas pressure has been applied.
 However, due at least in part to the fact that there are two separate
 pathways in the present assemblies, one being for gas and one for liquid,
 the liquid contents of the container is pushed to the very exit point of
 the liquid pathway by pre-existing gas pressure within the container. Now,
 when a per-activated coupling head is pressed into the I.D. of the
 housing, it will enter the liquid pathway before the coupling head seals
 against the container, thereby allowing the liquid contents to escape from
 the valve assembly and into the ambient atmosphere during the interval of
 time between initial liquid pathway opening and the time that the coupling
 head seals against the container.
 Another disadvantage of the valve arrangement disclosed in the Riis patent
 lies in the configuration of its safety mechanism for preventing the valve
 from being removed completely from the container before the gas pressure
 in the container has been fully vented. That safety mechanism includes a
 relatively complex structure including an outwardly projecting finger on
 the valve cup or housing and a catch on a downwardly extending protrusion
 on the stub. An upper edge of the catch protrudes far enough from the wall
 of the housing to abut the inner side of the stub in all positions of the
 riser pipe when the catch is in a first position thereof, thereby
 preventing valve removal. When the catch is deflected to a release
 position, the outer end of the catch is substantially flush with the inner
 surface of the stub permit valve removal. This configuration is expensive
 to manufacture because it requires the provision of a special stub that
 extends below the surface of the container. Its catch is also difficult to
 fabricate and difficult to operate.
 SUMMARY OF THE INVENTION
 In accordance with a first aspect of the invention, a valve assembly is
 provided for selectively permitting a liquid to be dispensed from a
 container under gas pressure within the container. The valve assembly is
 mountable on a stationary stub surrounding an aperture in the container
 and includes a valve seat, a valve element, and a valve cup. At least a
 portion of the valve element is movable between a first position in which
 the valve element seals against the valve seat to block pressurized gas
 flow into the container and a second position in which the valve element
 unseats from the valve seat to permit pressurized gas flow into the
 container and liquid flow out of the container. The valve cup is mounted
 in an opening of the container and cooperates with the valve element. A
 releasable retainer assembly is provided on an a radially and
 circumferentially distortable outer wall of the valve cup. The retainer
 assembly includes a protrusion that 1) tapers radially inwardly from an
 upper portion thereof to a lower portion thereof so as to act as a detent
 that is configured to engage the stub to distort the outer wall of the
 valve cup radially when the valve cup is inserted into the opening from
 above and which thereafter prevents vertical removal of the valve cup from
 the opening, and 2) tapers radially outwardly from a circumferential
 leading portion thereof to a trailing portion thereof to act as a ramp
 that is configured to engage the stub and to distort the outer wall of the
 valve cup when the valve cup is rotated with the retainer assembly in
 contact with the stub, thereby permitting the valve cup to be rotated out
 of the stub.
 The retainer assembly preferably further comprises first and second
 radially tapered, vertically extending centering skids that are spaced
 circumferentially from one another and from the protrusion. In order to
 permit the valve cup to rock about the centering skids to wedge the
 protrusion against the stub, both of the centering skids taper radially
 inwardly from a vertically central portion thereof towards opposed
 vertical ends thereof. In order to enhance the self-threading nature of
 the retainer assembly, an upper end of the protrusion preferably is
 positioned above an upper end of one of the first and second centering
 skids and beneath an upper end of the other of the first and second
 centering skids.
 Preferably, the protrusion includes 1) a detent portion which tapers
 radially inwardly from an upper portion thereof and 2) a self-threading
 ramp portion which is located circumferentially adjacent the detent
 portion and which tapers radially outwardly from a circumferential leading
 edge thereof to a circumferential trailing edge thereof.
 In accordance with another aspect of the invention, a method is provided
 for inserting a valve cup into an opening in a container and removing it
 from the opening. During the insertion step, a detent of a retainer
 assembly on the valve cup engages an annular member that surrounds the
 opening and forces an outer wall of the valve cup to elastically distort
 radially, thereby permitting the valve cup to be forced past the annular
 member and into the container. The removing step includes lifting the
 valve cup to an intermediate position in which additional vertical
 movement of the valve cup is blocked by engagement between an upper
 surface of the detent and a lower surface of the annular member, and then
 turning the valve cup relative to the annular member so as to cause a
 circumferentially tapered surface on the retainer assembly to engage the
 annular member and distort the outer wall of the valve cup, thereby
 permitting the valve cup to be rotated out of the stub.
 The removing step preferably comprises, after the step of lifting the valve
 cup to the intermediate position, tilting the valve cup to force the
 tapered surface against the annular member. During this tilting step, an
 upper portion of a first centering skid engages a vertical face of the
 annular member, and a lower portion of a second centering skid engages the
 vertical face of the annular member. Both of the centering skids taper
 radially inwardly from a vertically central portion thereof towards
 opposed vertical ends thereof.
 Preferably, during the turning step, the tapered surface self-threads
 against an essentially planar surface on the annular member.
 The foregoing and other features and advantages of the invention will
 become apparent from the following detailed description of the preferred
 embodiments, read in conjunction with the accompanying drawings. The
 detailed description and drawings are merely illustrative rather than
 limiting, the scope of the invention being defined by the appended claims
 and equivalents thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
 1. Resume
 Pursuant to the invention, a valve assembly has (1) a single valve cup
 which acts as the riser pipe and the valve housing and which has interior
 portals that are blockable, and (2) a central tower which communicates
 with blockable pathways that pass both liquid and gas, and (3) a
 bi-directional valve member which controls separation of gas and liquid
 and directional flow in the chamber, which allows only gas to be present
 at the point of coupling transition until the valve assembly is fully
 coupled, and that regulates the internal gas pressure of the container
 when no coupling is engaged. A retainer assembly is provided on the outer
 peripheral surface of the valve cup so as to (1) facilitate insertion of
 the valve cup into the container but (2) so as to prevent the unintended
 removal of the valve cup from the container while still permitting
 selective removal when it is desired to do so. The retainer assembly
 preferably includes a protrusion and a pair of centering skids spaced
 about the outer periphery of the valve cup. The protrusion includes a
 radially tapered, vertically extending detent portion and a radially
 tapered, circumferentially extending self-threading ramp portion. The
 centering skids taper radially inwardly from vertically central portions
 thereof to the vertical end portions thereof Upon simultaneous twisting
 and tilting of the valve cup relative to an annular member on the
 container, the centering skids engage the annular member so as to take up
 the clearance between the valve cup and the annular member, and the
 protrusion ramps onto the annular member in a self-threading manner so as
 to circumferentially distort the valve cup and to permit the valve cup to
 be turned out of the container. Due to this configuration, fewer parts are
 used in the same space, allowing for greater cross-sectional ingress and
 egress areas, thereby improving fill and discharge rates and reducing
 costs to the end user while providing improved safety. The parts can be
 made to retrofit existing equipment.
 2. Description of First Embodiment
 Turning now to the drawings and initially to FIGS. 1-4 in particular, the
 inventive valve assembly 20 is designed for connection to a standard stub
 22 surrounding an aperture 24 in a container 26. Container 26 may comprise
 a barrel or any other transportable or stationary structure for storing
 beverages or other liquids and for dispensing the stored liquids under gas
 pressure. The stub 22 coaxially surrounds the aperture 24 in the container
 26 and is fixed to the container 26, e.g., by welding. Stub 22 presents an
 internal radial shoulder 28 supporting the riser pipe or valve cup 34 as
 detailed below and also presents upper radial threads 30 for connection to
 a housing 32 of the valve assembly 20 also as detailed below.
 Valve assembly 20 includes as its major components a housing 32 which also
 functions as a retainer for the remaining components of the valve assembly
 20, a stationary riser pipe 34, a dispensing tower 36, and a sealing ring
 38. An annular chamber 40 is formed between the dispensing tower 36 and
 the riser pipe 34. This single chamber 40 contains liquid and/or gas
 depending upon the vertical position of sealing ring 38 within the chamber
 40. Dispensing tower 36 of the illustrated embodiment is movable
 vertically with respect to the riser pipe 34. The sealing ring 38 and
 dispensing tower 36 are biased towards the positions illustrated in FIG. 2
 by first and second springs 42 and 44 detailed below.
 The housing 32, which is threaded into the threads 30 of the stub 22,
 serves to enclose the remaining components of the valve assembly 20 and to
 retain them in place during operation of the assembly. The housing 32
 presents an internal ring 46 which defines an upper limit of travel of the
 sealing ring 38 as detailed below. Housing 32 also presents
 inwardly-extending radially lugs 47 for cooperation with a conventional
 coupling head in a manner which is, per se, well known.
 The riser pipe 34 functions both to serve as a valve cup, i.e., a housing
 and outer seat for the sealing ring 38, and as a more traditional pipe for
 directing liquid in the container 26 into the upper portions of the valve
 assembly 20 from the lower portions of the container. The riser pipe 34 is
 stepped so as to present a lower portion 48 of relatively narrow diameter
 separated from an upper portion 50 of relatively large diameter by a
 shoulder. Upper portion 50 surrounds the chamber 40 and slidably receives
 and guides the sealing ring 38. An outwardly radially extending flange 52
 is formed on the upper end of the riser pipe 34 and is clamped between the
 shoulder 28 of the stub 22 and the bottom end of the housing 32 with the
 aid of upper and lower sealing rings or gaskets 54 and 56. A plurality of
 circumferentially-spaced ingress/egress portals or openings 58 are formed
 in the upper portion 50 of the riser pipe 34 at a location beneath the
 flange 52.
 The purpose of the dispensing tower 36 is to provide a pathway for flow of
 liquid or gas (depending upon the operational state of the valve assembly)
 out of the container 26, to guide the inner periphery of the sealing ring
 38 during axial movement thereof, and to cooperate with the sealing ring
 38 to selectively prevent and permit fluid flow from the container 26. The
 dispensing tower 36 is sealed at its upper end by a cap 60 preferably
 formed integrally with the tubular tower. The lower end of the dispensing
 tower 36 is open and presents an outwardly extending radial flange 62
 which normally rests on the shoulder of the riser pipe 34. Triangular
 projections 64 are punched upwardly from the flange 62. Projections 64
 radially center the spring 44 and prevent excessive radial movement of the
 bottom end of the spring 44. A plurality of openings 66 are formed in the
 flange 62 when the projections 64 are punched. The openings 66 assure free
 flow of fluid between the annular chamber 40 and the interior of the riser
 pipe 34. In addition, a plurality of circumferentially spaced discharge
 openings or portals 68 are formed through the wall of the dispensing tower
 36 near its upper end.
 The sealing ring 38 performs two functions. First, it serves as a valve
 element, selectively opening and closing the portals 58 and 68 and
 exposing them to various fluids, i.e., either a gas or a liquid. Secondly,
 it guides the dispensing tower 36 and maintains the perpendicularity and
 eccentricity between the sealing ring 38, the dispensing tower 36, and the
 riser pipe 34, thereby enhancing sealing. The sealing ring 38 could
 conceivably be formed entirely out of rubber or another polymeric material
 but, in the illustrated embodiment (FIG. 2), is formed from an inner,
 rigid, thermally degradable, insert 70 surrounded by a layer 72 of a
 molded polymeric material such as synthetic or natural rubber.
 The outer portion of the upper end of the sealing ring 38 presents a
 chamfer 74 which complements the shape of the retaining ring 46 of housing
 32, 74 seals against 46 when the sealing ring 38 is in its uppermost
 position illustrated in FIG. 2. The inner radial portion of the upper end
 surface of the sealing ring 38 presents a flat sealing face 76 for contact
 with a spindle as detailed below. A first circular sealing lip 78 extends
 radially outwardly from the outer periphery of the sealing ring 38 and
 engages and seals against the internal surface of the riser pipe 34. The
 first sealing lip 78 is generally V-shaped and includes an upper sealing
 surface 80 and a lower sealing surface 82 both of which engage the
 internal surface of the riser pipe 34 and between which is formed an
 annular space that reduces contact friction and make the sealing lip very
 pliant. This can be enhanced with very slender annular face rib(s) on
 sealing surface 80 and 82 (not present in this embodiment). This generally
 V-shaped configuration of the lip 78 (1) provides bi-directional sealing
 at very low pressure, preventing fluid from flowing past the lip 78 either
 from above or below and (2) facilitates initial movement of the sealing
 ring 38 within the riser pipe 34 and prevents damage or abrasion of the
 sealing ring 38. A second circular V-shaped lip 84 extends radially
 inwardly from the inner peripheral surface of the sealing ring 38 and is
 positioned above the discharge portals or openings 68 when the valve
 assembly 20 is in its neutral or closed position illustrated in FIG. 2.
 Finally, a plurality of frusto-conical centering projections 86 extend
 radially from the sealing ring 38. These projections 86 could extend from
 the inner peripheral surface of the sealing ring 38 as illustrated, from
 the outer peripheral surface, or from both. They also could be
 supplemented or replaced by diagonal, and/or spiral, or vertical ribs (not
 present in this embodiment). These projections 86 guide and stabilize the
 sealing ring 38 with respect to the member they contact (the dispensing
 tower 36 in the illustrated embodiment) while maintaining the eccentricity
 of these elements and permitting the free-flow of fluid past the
 projections 86. The illustrated projections 86 are formed integrally with
 the polymeric layer 72, but it is conceivable that they could be formed
 from a separate structure or even from projections of the insert 70
 extending through the polymeric layer 72. Sealing ring 38 is biased into
 its uppermost position illustrated in FIG. 2 both by the first or sealing
 spring 42 and the second or vent spring 44. The sealing spring 42 is
 seated against the bottom surface of the insert 70 at its upper end and
 against a step in the riser pipe 34 at its upper end. The second or vent
 spring 44 is seated at its lower end against the flange 62 of the
 dispensing tower 36 and at its upper end against a spacer 88 positioned
 between the spring 44 and the bottom surface of the polymeric layer 72.
 There are three modes of operation associated with the valve assembly 20
 illustrated in FIGS. 1-4, namely: (1) neutral/closed (FIG. 2), (2)
 working/open to gas ingress and liquid egress (FIG. 3), and (3)
 venting/relieving excess pressure from within the container 26 (FIG. 4). A
 detailed discussion of each follows.
 The neutral or closed position of the valve assembly 20 is illustrated in
 FIG. 2. The outer sealing lip 78 of the sealing ring 38 seals against the
 riser pipe 34 at a location above ingress/egress openings or portals 58,
 and the inner sealing lip 84 seals against the dispensing tower 36 at a
 location above the discharge portals 68. The chamfer 74 is held against
 the ring 46 of the housing 32 by the combined force of springs 42 and 44
 and spacer 88. The arrangement of the members in this operational state
 differs from known assemblies in that the ingress/egress portals 58 and
 the discharge portals 68 share the same gas pressure, present throughout
 chamber 40 due to gas flow among the conical projections 86, thereby
 allowing the liquid in container 26 to seek its own level away from
 portals 58 and 68 via the inlet of the riser pipe 34. This in turn
 improves the coupling safety when a coupling arrangement is attached to
 the valve assembly 20.
 Turning now to FIG. 3, the valve assembly 20 is placed in its second mode
 of operation in which it is open to gas ingress and liquid egress. Sealing
 ring 38 has been forced downwardly by a conventional fixed external
 coupling arrangement such as the arrangement manufactured by Perlick and
 marketed as Model No. MK-1. The conventional coupling arrangement includes
 an internal, axially displaceable, hollow spindle 90 which, when pressed
 downward, contacts the upper sealing face 76 of the sealing ring 38 (the
 ID of the spindle 90 being bored slightly if necessary to accommodate the
 present invention. In addition, an internal radially-extending riser stop
 and a separate internal V-shaped seal can if desired be added to the
 spindle) and forces the sealing ring 38 downwardly from the position
 illustrated in FIG. 2 to the position illustrated in FIG. 3. Coupling of
 the spindle 90 to the sealing face 76 creates (1) an ingress tube in the
 region located radially outside of the spindle 90 for flow of the
 propellant gas into the container 26, and (2) an egress tube within the
 spindle 90 for the flow liquid out of the container 26. The integrity of
 the gas and liquid separation at the circular line of contact between the
 spindle 90 and the sealing face 76 of the sealing ring 38 is maintained by
 the upward pressure of sealing spring 42. Seal integrity is enhanced
 further by the conical projections 86 and/or vertical ribs (not shown)
 fixed on the I.D. and/or O.D. walls of the sealing ring 38. As discussed
 above, these projections 86 serve to guide and stabilize the
 perpendicularly and eccentricity between the sealing ring 38, dispensing
 tower 36, and riser pipe 34, thereby enhancing the sealing of the outer
 and inner sealing lips 78 and 84 of the sealing ring 38 as they move
 downwardly past the ingress/egress openings or portals 58 of riser pipe 34
 and the discharge openings or portals 68 of dispensing tower 36,
 respectively.
 It is important to note that the sequence of portal overlap and exposure is
 timeable by setting differential relationships between the sealing lip and
 portal locations during valve manufacture. The valve assembly 20 therefore
 can be readily modified to allow the valve assembly 20 to mix more then
 one liquid or gas in the same chamber 40, with the differential between
 them being controllable by design.
 When the sealing ring 38 is forced downwardly to the position illustrated
 in FIG. 3, (1) the ingress/egress portals 58 are exposed to propellant gas
 flowing into the valve assembly 20 from the region surrounding the spindle
 90, and (2) the discharge portals 68 are exposed to the internal fluid
 discharge passage of the spindle 90. Outer sealing lip 78 prevents the
 propellant gas from entering the liquid at a location just below portals
 58. Sealing lip 78 therefore preserves ingress propellant pressure
 integrity as the gas flows into the container 26. In addition, the sealing
 lip 78 prevents liquid from entering the ingress/egress portals 58 and
 thus closes the riser pipe being off to its gas connection. This in turn
 forces the gas now entering the container 26 through the ingress/egress
 portals 58 to push the liquid up into the lower inlet of the riser pipe
 34, up through the center of dispensing tower 36, and out of the
 dispensing tower 36 through the discharge portals 68. The discharged
 liquid then flows through the spindle 90 and is dispensed from the system
 in a conventional manner.
 Conversely, when there is no external coupling attached to valve assembly
 20, springs 42 and 44 return the sealing ring 38 to its neutral or closed
 mode as illustrated in FIGS. 2 and 4, thereby containing liquid and gas
 within container 26 for transport. The inventive valve assembly 20
 therefore exhibits the same benefit as previously-known valve assemblies
 which also contain liquid and gas within their containers for transport
 when they are closed.
 However, unlike conventional valve assemblies, the inventive valve assembly
 20 also is capable of operating in a pressure relief mode. Pressure relief
 is desirable because the contents of the container 26 can be exposed to
 thermal agitation such as fire or mechanical agitation such as excessive
 shaking. External agitation may cause gas pressure within the container 26
 to build-up to a level that is high enough to breach the container's
 integrity with devastating consequences. This potential overpressurization
 is avoided by permitting the valve assembly 20 to assume the mode
 illustrated in FIG. 4 in which pent-up gas pressure within the container
 26 overcomes the seal between the inner sealing lip 84 of the sealing ring
 38 and the dispensing tower 36. That is, gas pressure acting on the
 dispensing tower 36 forces the tower 36 upwardly against the spring 44 to
 a position where portals 68 vent. Since the sealing ring 38 is held from
 upward movement by the ring 46 of the housing 32, the discharge or egress
 portals 68 of the discharge tower 36 move beyond the inner sealing lip 84
 to permit excess pressure within the container to flow past the riser pipe
 34, through ingress/egress portals 58, through the dispensing tower 36,
 and out of the valve assembly 20 through the discharge portals 68. It
 should be noted that, because upward movement of the dispensing tower 36
 is resisted primarily by the spring 44, the threshold pressure above which
 relief or venting occurs is determined by the strength of the spring 44
 and can be set by selecting a spring of a designated strength. In those
 instances in which overpressurization results from thermal agitation
 caused by fire or the like, pressure release can be accelerated through
 thermal degradation of the insert 70 and consequent ejection of the entire
 sealing ring 38 from the valve assembly 20.
 The valve assembly could take many forms from that illustrated and
 described above without departing from the basic principals of operation.
 A first alternative construction of the inventive valve assembly will now
 be described.
 3. Description of Second Embodiment
 Referring to FIGS. 5-8, components of the valve assembly 220 of the second
 embodiment corresponding to components of the valve assembly 20 of the
 first embodiment (illustrated in FIGS. 1-4) are designated by the same
 reference numerals, incremented by 200. The valve assembly 220 of FIGS.
 5-8 differs from the valve assembly 20 of FIGS. 1-4 in that (1) the
 sealing ring 238 is of slightly different design, (2) one of the springs
 of the first embodiment has been eliminated, and (3) dispensing tower 236
 has been redesigned to accommodate the elimination of one of the springs.
 These discrepancies from the first embodiment will now be detailed.
 Sealing ring 238 is configured for sliding movement in the chamber 240 in
 the same manner as the sealing ring 38 of the first embodiment. However,
 this sealing ring 238, unlike the sealing ring 38 of the first embodiment,
 is formed of a single unitary polymer member and thus lacks the
 rigidifying insert of the first embodiment. Additional centering
 projections 287 also are provided on the outer radial periphery of a
 sealing ring 238, and vertical centering ribs 285 are provided on the
 outer radial periphery to help guide the sealing ring 238 as it moves
 along the valve cup or riser pipe 234.
 The sole spring 242 of the second embodiment is designed to interact with
 the elastomeric sealing ring 238 to perform the combined functions of both
 springs 42 and 44 of the first embodiment. The spring 242 urges against
 the bottom surface of the sealing ring 238 at its upper end and against
 the annular flange 262 of the dispensing tower 236 at its lower end. The
 generally triangular projections 264 of this flange 262 are spaced further
 towards the inner edge of the flange 262 when compared to the
 corresponding projections 64 of the first embodiment to accommodate the
 larger spring. Finally, the relative positional relationship between the
 sealing lips 278 and 284, the ingress/egress openings or portals 258, and
 the discharge openings or portals 268 has been varied slightly to
 accommodate the revised sealing ring configuration.
 Operation of the valve assembly 220 of the second embodiment is essentially
 identical to the operation of the valve assembly 20 of the first
 embodiment. Hence, when the valve assembly 220 is in its neutral closed
 mode illustrated in FIG. 5, the outer sealing lip 278 is located above the
 ingress/egress portals 258 and sealed against the internal surface of the
 riser pipe 234, the inner sealing lip 284 is located above the discharge
 portals 268 and sealed against the external surface of the dispensing
 tower 236, and the chamfer 274 is sealed against the ring 246.
 Accordingly, the entire portion of the chamber 240 beneath the sealing
 ring 238 is subject to whatever gas pressure exists within the container
 226, and egress of fluids from the dispensing tower 236 is prohibited by
 the inner sealing lip 284.
 In the working mode, shown in FIG. 6, the sealing ring 238 of the second
 embodiment is forced downwardly by a hollow spindle 290 against spring 242
 to the illustrated position in which the outer and inner sealing lips 278
 and 284 are positioned beneath the respective rows of portals 258 and 268.
 The integrity of the gas and liquid separation at the interface between
 the spindle 290 and the sealing face 276 is maintained by the upward
 pressure of control spring 242. The inner and outer conical projections
 286 and 287 and/or vertical ribs 285, fixed on the I.D. and/or O.D. walls
 of sealing ring 238, guide and stabilize the perpendicularly and
 eccentricity between the sealing ring 238, the dispensing tower 236, and
 the riser pipe 234, thereby enhancing the sealing of the lips 278 and 284
 as they move downwardly past the discharge portals 268 of dispensing tower
 236 and the ingress/egress portals 258 of riser pipe 234. As in the first
 embodiment, the sequence of portal blockage and opening is timeable by
 setting or altering the differential relationships between the sealing lip
 and portal locations. The operation of the valve assembly 220 in its
 working mode is otherwise the same as the operation of the valve assembly
 20 of the first embodiment in its working mode and, accordingly, will not
 be detailed.
 Conversely, when, as illustrated in FIG. 7, there is no external coupling
 attached to the valve assembly 220, the sole spring 242 of the assembly
 returns the sealing ring 238 to its neutral or closed state, thereby
 containing liquid and gas within the container 226 for transport. However,
 if the contents of the container 226 become overpressurized due, e.g., to
 thermal agitation, the excess pent-up pressure will force dispensing tower
 236 upwardly against the force of control spring 242 to the illustrated
 position venting said pressure through discharge portals 268 which are now
 located above the inner sealing lip 284 of the sealing ring 238, in the
 same manner detailed above in connection with the first embodiment.
 4. Description of Third Embodiment
 Turning now to FIGS. 9-12, a valve assembly 320 constructed in accordance
 with a third embodiment of the invention is illustrated which is similar
 to the valve assembly 220 of the second embodiment. Components of the
 third embodiment corresponding to those of the second embodiment are,
 accordingly, designated by the same reference numerals, incremented by
 100.
 The valve assembly 320 of the third embodiment differs from the valve
 assembly 220 of the second embodiment primarily in that the dispensing
 tower 336 takes the form of an imperforate standpipe assembly rather than
 a perforated hollow pipe. The dispensing tower 336 therefore includes an
 upper head 361 of relatively large diameter and a lower shank 363 of
 relatively small diameter separated by a downwardly facing shoulder 369 on
 the head 361. An annular plate 362 is affixed to the bottom end portion of
 the shank 363 and serves the same function as the annular flange 262 of
 the second embodiment, namely, it supports the spring 342 and has
 projections 364 bend upwardly therefrom to guide the spring 342 and to
 form opening 366 for fluid flow through the plate 362. The ribs 385 are
 mounted on the shank 363 rather than the sealing ring 338 to illustrate
 that centering devices could be mounted on either or both members.
 The sealing ring 338 of the third embodiment differs from the sealing ring
 238 of the second embodiment in that its inner portion is modified to
 cooperate with the standpipe or dispensing tower 336. Specifically, as is
 clearly illustrated in the drawings, the inner peripheral surface of the
 sealing ring 338 is stepped so as to present an axial shoulder or sealing
 face 377 on which the mating shoulder 369 of the dispensing tower 336
 sealingly rests when the valve assembly 320 is in its neutral or closed
 mode illustrated in FIG. 9. In the other two modes of operation,
 illustrated in FIGS. 10 and 11, respectively, sealing face 377 is spaced
 from the shoulder 369 of the dispensing tower 336 to permit fluid flow
 therepast and out of the valve assembly 320.
 The operation of the valve assembly 320 of the third embodiment is
 generally the same as the operation of the valve assembly 220 of the
 second embodiment. The sealing ring 338 moves downwardly within the
 chamber 340, under the action of a spindle 390 of a coupling head and
 against the biasing force of the spring 342, from its neutral or closed
 position illustrated in FIG. 9 to its working or open position illustrated
 in FIG. 10. The integrity of the gas and liquid separation at the
 spindle-to-sealing ring coupling is maintained before and after this
 motion by the upward pressure of control spring 342 and by conical
 projections 386 and 387 and/or vertical ribs 385, which help stabilize the
 perpendicularly and eccentricity between the sealing ring 338, dispensing
 tower 336, and riser pipe 334, thereby enhancing the sealing of the
 sealing lip 378 as the sealing ring 338 moves downwardly past the
 ingress/egress portals 358 of the riser pipe 334. Movement of the sealing
 ring 338 relative to the dispensing tower 336 causes the sealing face 377
 of the sealing ring 338 to separate from the mating shoulder 369 on the
 dispensing tower 336, thereby permitting liquid to flow between the
 sealing ring 338 and the dispensing tower 336, out of the valve assembly
 320, and into the egress tube formed by the spindle 390. As in the
 previous embodiments, this is a sequence that is timeable by altering the
 differential relationships between the sealing lip and portal and shoulder
 locations. The operation of the valve assembly 320 in its working mode is
 otherwise the same as in the first and second embodiments and,
 accordingly, will not be detailed.
 When, as illustrated in FIGS. 9 and 11, there is no external coupling
 attached to valve assembly 320, spring 342 returns the sealing ring 338 to
 its neutral or closed state, thereby containing liquid and gas within
 container 326 for transport. In the event of pressure build-up within the
 container 326 due to the imposition of thermal or mechanical agitation,
 excess pressure in the container 326 will force the dispensing tower 336
 upwardly, against the biasing force of control spring 342, so that (1) the
 bottom horizontal plane or shoulder 369 of the large diameter or head 361
 of the post or dispensing tower 336 moves past the horizontal plane or
 sealing face 377 of the sealing ring 338. The pressurized gas in the
 container 326 is then free to vent through the ingress/egress portals 358
 of riser pipe 334, then through the center of the sealing ring 338, past
 the open egress pathway between the sealing ring 338 and the dispensing
 tower 336, and out of the valve assembly 320.
 5. Description of Fourth Embodiment
 Still another embodiment of the invention is illustrated in FIGS. 13-16.
 The valve assembly 420 constructed in accordance with this fourth
 embodiment differs from the valve assembly 20 of the first embodiment
 primarily in that, in a pressure relief or venting mode, the dispensing
 tower 436 is held stationary and the sealing ring 438 moves upwardly to
 achieve the desired venting. Several relatively minor structural changes
 are made to the valve assembly 420 to permit this alternate operation.
 However, the valve assembly 420 of this embodiment is for the most part
 similar in construction and operation of the valve assembly 20 of the
 first embodiment. Components of this embodiment corresponding to
 components of the first embodiment are, accordingly, designated by the
 same reference numerals, incremented by 400. Those features which are
 altered with respect to the first embodiment will now be detailed.
 First, the sealing ring 438 does not engage the ring 446 of the housing 432
 when the valve assembly 420 is in its neutral or closed position
 illustrated in FIG. 13. Rather, the sealing ring 438 is held in a neutral
 position in which it is spaced between the housing ring 446 and the
 ingress/egress portals 458 of the riser pipe 434 under the balancing
 action of the sealing spring 442 and a second, venting spring 444 acting
 against the sealing spring 442. The venting spring 444 is positioned
 axially between the housing ring 446 and the sealing ring 438 and is
 configured to apply a downward biasing force on the sealing ring. Contact
 between an intermediate axial portion of the sealing ring and the spring
 444 is made possible by configuring the sealing ring 438 such that it is
 somewhat longer than the sealing ring 38 of the first embodiment and such
 that it has a stepped outer peripheral surface so as to present an
 upwardly facing shoulder 488 on which the spring 444 rests.
 Second, the bottom flange or ring 462 of the dispensing tower 436 is larger
 in diameter than the flange or ring of the first embodiment and is held in
 its illustrated position by a retaining ring 463 mounted in the riser pipe
 434, and/or protrusions within riser pipe 434.
 The operation of the valve assembly 420 constructed in accordance with the
 fourth embodiment will now be described.
 In the neutral or closed position of the valve assembly 420 illustrated in
 FIG. 13, the outer sealing lip 478 of the sealing ring 438 seals against
 the riser pipe 434 at a location above ingress/egress portals 458, and the
 inner sealing lip 484 seals against the dispensing tower 436 at a location
 above the discharge portals 468. The sealing ring 438 is held in its
 illustrated neutral position by the opposing forces of the upper venting
 spring 444 and the lower sealing spring 442. As in the previous
 embodiments, the ingress/egress portals 458 and discharge portals 468
 share the same gas pressure, present throughout chamber 440 due to the
 flow of gas among the projections 486, thereby allowing the liquid in
 container 426 to seek its own level away from portals 458, which in turn
 improves the coupling safety when a coupling arrangement is attached to
 the valve assembly 420.
 Turning now to FIG. 14, the valve assembly 420 is placed in its working
 mode of operation in which it is open to gas ingress and liquid egress by
 driving the sealing ring 438 downwardly, against the force of the spring
 442, using a spindle 490 of a conventional fixed external coupling
 arrangement. The spindle 490 comes into contact with the upper sealing
 face 476 of the sealing ring 438 and forces the sealing ring 438
 downwardly from the position illustrated in FIG. 13 to the position
 illustrated in FIG. 14. As in the previous embodiments, coupling of the
 spindle 490 to the sealing face 476 creates an ingress tube radially
 outside of the spindle 490 for flow of the propellant gas into the
 container 426, and an egress tube within the spindle 490 for the flow
 liquid out of the container 426. The integrity of the gas and liquid
 separation at the circular line of contact between the spindle 490 and the
 sealing face 476 is maintained by the upward pressure of sealing spring
 442. Seal integrity is enhanced further by the conical projections 486
 and/or vertical ribs (not shown in this embodiment), fixed on the I.D.
 and/or O.D. walls of the sealing ring 438, in the manner discussed above
 in connection with the previous embodiments.
 When the sealing ring 438 is forced downwardly to the position illustrated
 in FIG. 14, (1) the ingress/egress portals 458 are exposed to propellant
 gas flowing into the valve assembly 420 from the region surrounding the
 spindle 490, and (2) the discharge portals 468 are exposed to the internal
 fluid discharge passage of the spindle 490. Outer sealing lip 478 prevents
 the propellant gas from entering the liquid at a location just below the
 portals 458 of riser pipe 434. Sealing lip 480 therefore preserves ingress
 propellant pressure integrity as pressurized gas flows into the container
 426, and sealing lip 482 also prevents the liquid from entering the
 portals 458 of riser pipe 434, resulting in the riser pipe 434 being
 closed off to its gas connection. This in turn forces the gas now entering
 the container 426 through the portals 458 of riser pipe 434 to push the
 liquid up the inlet of the riser pipe 434, up through and about the center
 of dispensing tower 436, enhancing the seal of sealing lip 484 and then
 out of the dispensing tower through the discharge portals 468. The
 discharged liquid then flows through the spindle 490 and is dispensed from
 the system in a conventional manner.
 Conversely, when there is no external coupling attached to valve assembly
 420, springs 442 and 444 return the sealing ring 438 to its neutral or
 closed mode as illustrated in FIG. 13, thereby containing liquid and gas
 within container 426 for transport. If gas pressure within the container
 426 increases to excessive levels, the valve assembly 420 assumes the mode
 illustrated in FIG. 15 in which pent-up gas pressure within the container
 426 overcomes the seal between the inner sealing lip 484 of the sealing
 ring 438 and the dispensing tower 436. That is, gas pressure acting on the
 sealing ring 438 forces the sealing ring 438 upwardly against the biasing
 force of the upper spring 444. Since the dispensing tower 436 is held from
 upward movement by the ring 463 of the riser pipe 434, the inner sealing
 lip 484 of the sealing ring 438 moves beyond the upper end 460 of the
 dispensing tower 436 to expose the discharge portals or openings 468 of
 the dispensing tower to the ambient atmosphere. Excess pressure within the
 container 426 can then flow past the riser pipe 434, through
 ingress/egress portals 458, through the dispensing tower 436, and out of
 the valve assembly 420 through the discharge portals 468.
 6. Description of Fifth Embodiment
 Still yet another embodiment of the invention is illustrated in FIGS.
 17-21. Valve assembly 520 constructed in accordance with this fifth
 embodiment differs from the valve assembly 320 of the third embodiment
 primarily in that the dispensing tower 536 is movable downwardly to
 accommodate the flow of liquid in the normal dispensing mode between
 sealing ring 538 and the dispensing tower 536. Several structural changes
 are made to the valve assembly 520 to permit this alternative operation
 and to achieve other advantages. However, the valve assembly 520 of this
 embodiment is, for the most part, similar in construction and operation to
 the valve assembly 320 of the third embodiment. Components of this
 embodiment corresponding to components of the third embodiment are,
 accordingly, designated by the same reference numerals, incremented by
 200. These components include a valve housing 532, a stationary riser pipe
 534, a dispensing tower 536, and a sealing ring 538 which is disposed in
 an annular chamber 540 formed between the dispensing tower 536 and the
 riser pipe 534. The valve assembly 520 also includes first and second
 springs 544 and 542 and an O-ring seal 556. Also as in the previous
 embodiments, the valve assembly 520 is configured for fitting into a
 standard stub 522 of a container 526. Those features which are altered
 with respect to the third embodiment will now be detailed, the remaining
 features being discussed only to the extend necessary to facilitate an
 understanding of the operation of the valve assembly 520.
 As in the previous embodiments, the riser pipe 534 is mounted on an annular
 shoulder 528 of the stub 522 and extends into an inlet 524 formed in the
 container 526. However, the riser pipe 534 differs from the riser pipes of
 the previous embodiments primarily in that it is tapered inwardly as
 illustrated so that the lower end of the sealing ring 538 seals against
 the riser pipe 534 as the sealing ring 536 moves downwardly during valve
 actuation. Moreover, and as discussed below, the riser pipe 534 is sealed
 to the valve housing 532 so that the valve housing 532, in effect, forms
 an extension of the riser pipe.
 The dispensing tower 536 differs significantly from the dispensing towers
 of the previous embodiments.
 For instance, rather than being of one-piece construction, it is formed
 from two parts, namely 1) a plastic body 535 and 2) a metal contact ball
 537. The contact ball 537, preferably formed from stainless steel, is
 inserted into a socket 539 formed in the upper end of the body 535. The
 ball 537 projects just above the uppermost surface of the body 535 and
 presents a rigid contact surface for a lower protrusion 592 of a spindle
 590 when the spindle 590 is inserted into the valve assembly 520 as
 detailed below in conjunction with FIG. 18. The ball 537 serves to
 maintain the circular shape of the uppermost portion of the body 535 and
 also prevents wear and tear to the dispensing tower 536 which might
 otherwise occur from coming into contact with the spindle 590.
 The body 535 could be formed from any dimensionally stable food-grade
 material, and preferably is formed from a food-grade plastics materials
 for cost and weight considerations. An especially preferred material is
 polysulfone, which is manufactured by Amoco Corp. Polysulfone is preferred
 because it is rigid, durable, and easy to fabricate. The material also has
 very closed cell surfaces which inhibit contamination and which make the
 material ideally suited for use in food processing equipment. In addition,
 the material is capable of withstanding temperatures from -150 degrees
 Fahrenheit to +300 degrees Fahrenheit. The body 535 includes an upper
 annular shoulder 561 which is biased into sealing engagement with the
 sealing ring 538 via the spring 542. Spring 542 abuts an intermediate
 radial shoulder 533 on the body 535 at its upper end and abuts an internal
 flange 531 of the riser pipe 534 at its lower end. A portion of the body
 535, extending from the ball 537 to the intermediate shoulder 533, is in
 the shape of a circular hourglass conic so that both ends of this portion
 are wider than a center of this portion.
 In addition, and unlike in the previous embodiments in which the dispensing
 tower is incapable of downward movement from its neutral position, the
 dispensing tower 536 is slidable downwardly independently of the sealing
 ring 538. The dispensing tower 536 of this embodiment also upwardly moves
 relative to the sealing ring 538 in the pressure relief mode. Measures
 therefore are preferably incorporated into the design of the dispensing
 tower 536 to permit fluid flow between the dispensing tower 536 and the
 sealing ring 538 during pressure relief. Towards these ends, the body 535
 of the dispensing tower 536 is formed with one or more external channels
 or grooves 541 in the surface thereof that extend at least generally
 axially from the bottom of the dispensing tower 536 to just above the
 shoulder 533. In the illustrated embodiment, and as best seen in FIG. 21,
 several channels 541 are formed by forming the lower portion of the body
 535 with a fluted or generally cross-shaped cross section to form four
 such channels 541 around the periphery of the lower portion of dispensing
 tower 536. However, a lesser or greater number of channels could be formed
 to accommodate more or less flow, for example.
 The sealing ring 538, and particularly the outer periphery thereof, could
 be identical in construction and operation to the sealing ring 338 of the
 third embodiment. However, the illustrated and currently-preferred sealing
 ring 538 differs from the sealing rings the first and third embodiments
 primary in that 1) it lacks the pronounced sealing lips and 2) it seals
 against the valve housing 532 rather than the riser pipe 534 when it is in
 its neutral or closed position. The sealing ring 538 also curves inwardly
 at its upper end to form a lip-like structure (hereafter known simply as a
 "lip" 574). As best seen in FIG. 17, lip 574 acts as a stop against which
 the shoulder of the dispensing tower 536 seals when the valve assembly 520
 assumes its neutral or closed position. The lip 574, and preferably the
 entire sealing ring 538, is made of a resilient material such as neoprene
 or EPDM, or other resilient material suitable for use in connection with
 food or beverage containers.
 The functions of the outer sealing lip of the previous embodiments are
 performed in this embodiment by upper and lower sealing members 543 and
 545 which sequentially seal at locations above and below the
 ingress/egress portals 558 as the sealing ring 538 moves downwardly in the
 chamber 540. The upper sealing member 543 comprises a stepped shoulder
 which engages a stepped groove 579 in valve housing 532 when the valve
 assembly 520 assumes its neutral or closed position. Stepped groove 579
 presents a double seal so that at least two surfaces of the upper sealing
 member 543 are sealingly engaged when the valve is closed. Stepped groove
 579 also serves as a stop that retains the sealing ring 538 in the valve
 assembly 520. The sealing ring 538 is biased into engagement with the
 stepped groove 579 by the spring 544, which rests in a spring groove 577
 in the base of the sealing ring 538 at its upper end and on an
 intermediate radial flange 578 of the riser pipe 534 at its lower end. The
 lower sealing member 545 takes the form of an outer peripheral surface of
 the lower portion of the sealing ring 538 which sealingly engages the
 tapered riser pipe 534 as the sealing ring 538 moves downwardly within the
 chamber.
 In addition, and as in the previous embodiments, a plurality of centering
 projections are provided on the I.D and/or the O.D. of the sealing ring
 538 to guide and stabilize the sealing ring 538 with respect to the member
 they contact while maintaining the eccentricity of these elements and
 permitting the free-flow of fluid past the projections. In the illustrated
 embodiment, centering projections 587 are formed integrally with the
 remainder of the sealing ring 538 and abut the riser pipe 534 so as to
 guide and stabilize the sealing ring 538 with respect to the riser pipe
 534. The projections 587 may be either arcuate as illustrated,
 frusto-conical as in the previous embodiments, or any other desired shape.
 Projections may, if desired, be provided on the L.D. of the sealing ring
 538 instead of or in addition to the projections 587 in order to guide and
 stabilize the sealing ring 538 relative to the dispensing tower 536.
 An additional feature of the fifth embodiment is the substitution of a
 layer 554 of structural two-part adhesive for the sealing ring or gasket
 of the preferred embodiment such as the sealing rings 54 and 354 of the
 first and third embodiments. Adhesive layer 554 provides the same sealing
 capability of the sealing rings and also adds additional structural
 integrity to the joint, thereby unifying valve housing 532 and the riser
 pipe 534 into a single riser pipe. The layer 554 is sealed against the
 stub 522 by an O-ring seal 556 that engages a radius or curved surface 557
 on the inner surface of the layer 554. This relationship helps clamp the
 O-ring 556 into position more clearly and to prevent it from twisting,
 thereby enhancing the integrity of the seal.
 In the neutral or closed mode, best seen in FIG. 17, dispensing tower 536
 is sealingly urged against sealing ring 538 by the second spring 542, and
 the upper seal 543 of the sealing ring 538 is sealingly urged against the
 annular groove 579 by both springs 544 and 542. As a result, and as in the
 previous embodiments, the ingress/egress portals 558 and chamber 540 share
 the same pressure, thereby allowing the liquid in container 526 to seek
 its own level away from portals 558 via the inlet of the riser pipe 534.
 This in turn improves the coupling safety when a coupling arrangement is
 attached to the valve assembly 520.
 As best shown in FIG. 18, when a spindle 590 is inserted into the bore of
 the valve assembly 520 and turned on its axis, it engages a pair of lugs
 547 (FIG. 21) in bayonet-like fashion in a manner which is, per se, well
 known. Alternatively, the spindle 590 may be threaded into the bore of the
 valve assembly 520. The spindle 590 illustrated in FIG. 18 has been custom
 modified from the standard spindle in order to present a cylindrical
 radially centered axial projection 592 on the end of spindle 590.
 Projection 592 serves to drive the dispensing tower 536 downwardly against
 the force of second spring 542 to create a valve opening between
 dispensing tower 536 and the lip 574 of sealing ring 538 so as to permit
 the passage of liquid through the valve opening, through a number of
 radial holes 593 in the projection 592, and up into the liquid channel 594
 of spindle 590.
 The spindle 590 also contacts sealing ring 538 as it moves downwardly and
 forces sealing ring 538 downwardly to expose portals 558 to incoming gas.
 In addition, downward movement of sealing ring 538 also causes the lower
 sealing member 545 of sealing ring 538 to snugly seal against the tapered
 stationary riser 534 at a location beneath ingress/egress portals 558.
 Gas/liquid separation therefore is maintained in the same manner as in the
 previous embodiments. Gas can now enter the container 526 through the
 portals 558 of riser pipe 534 to push the liquid up the inlet of the riser
 pipe 534, between the dispensing tower 536 and the sealing ring 538, and
 into the spindle 590, where the fluid is dispensed from the system in a
 conventional manner.
 Referring now to FIG. 19, the valve assembly 520 is illustrated in a
 wash/fill mode of operation. In order to accommodate rapid washing and
 filling of container 526, dispensing tower 536 is capable of even further
 downward movement than the movement required for the normal dispensing
 mode. A wash/fill fitting 595 is inserted into the bore of the valve
 assembly 526 and has a wash/fill protrusion 596 extending downwardly
 therefrom to displace the dispensing tower 536 downwardly. This protrusion
 is longer than the projection 592 of the dispensing spindle 590 so as to
 effect greater relative movement between the dispensing tower 536 and the
 sealing ring 538. This movement is sufficient to force the shoulder 561 of
 the dispensing tower 536 to a position far enough beneath the lip 574 of
 the sealing ring 538 to maximize the area of the annular opening between
 the dispensing tower 536 and the sealing ring 538. This large opening
 accommodates the rapid flow of liquid into container 526 from an internal
 passage 597 and discharge holes 598 of the wash/fill fitting 595 to
 facilitate washing and filling of the container 526 and valve assembly
 520. At the same time, the wash/fill fitting 595 displaces sealing ring
 538 downwardly to open portals 558 and to also sealingly engage the I.D.
 of riser pipe 534 just below portals 558. In this way, as liquid is forced
 downwardly into the valve assembly 520 in the wash/fill mode, ingress or
 egress of gas is permitted through portals 558. Conversely, gas may be
 forced back into the container 526 through portals 558 to accomplish rapid
 evacuation of the container 526.
 The pressure relief mode is illustrated in FIG. 20. In previous
 embodiments, the. pressure relief function of the valve assembly is
 regulated by the tension of the spring 44. In this embodiment, as pressure
 builds on dispensing tower 536, from below, forces generated by this
 pressure are opposed by the retaining forces imposed on the dispensing
 tower 536 by the lip 574. Since sealing ring 538 is made from a resilient
 material such as EPDM or neoprene, the lip 574 deforms to permit the
 dispensing tower 536 to move or "pop" up through the sealing ring 538 when
 the gas pressure from within the container 526 reaches a sufficient
 magnitude. This movement exposes the upper openings of channels 541 of the
 dispensing tower 536 to the atmosphere and permits fluid to flow up
 through the channels 541 and out of the bore of the valve assembly 520.
 The upper portion of intermediate radial shoulder 533 on the body 535
 prevents the dispensing tower 536 from completely exiting the valve
 assembly 520 during this process. After excess pressure has been released
 from the container 526, it is necessary to "reset" the valve assembly 520
 by manually or mechanically forcing the dispensing tower 536 back to its
 neutral position beneath the lip 574 of the sealing ring 538.
 7. Description of Sixth Embodiment
 Still yet another embodiment of the invention is illustrated in FIGS.
 22-36. Valve assembly 620 constructed in accordance with this embodiment
 differs from the valve assembly 520 of the fifth embodiment primarily in
 that a releasable retainer assembly 710, 712, 714 is provided to prevent
 unintentional removal of the valve assembly 620 from the container 626.
 Components of this embodiment corresponding to components of the fifth
 embodiment are, accordingly, designated by the same reference numerals,
 incremented by 100. These components include a valve housing 632, a
 stationary riser pipe 634 including an integral valve cup 631, a
 dispensing tower 636, and a sealing ring 638 which is disposed in an
 annular chamber 640 formed between the dispensing tower 636 and the valve
 cup 631. The movable components of the valve assembly 620 are biased
 toward their closed position by first and second springs 642 and 644. The
 valve assembly 620 is configured for fitting into a standard bung or stub
 622 mounted over an opening 624 in container 626. The valve cup 631 is
 mounted on an annular shoulder 628 of the stub 622 and extends into the
 opening 624. The top of the valve cup 631 is sealed to the valve housing
 632 so that the valve housing 632, in effect, forms an extension of the
 riser pipe 634. In addition, an O-ring seal 656 is clamped between the
 shoulder 628 on the stub 622 and a lower radius or curved surface 653 on
 an annular collar 655 on the valve cup 631. As in the similar construction
 of the fifth embodiment, this relationship helps clamp the O-ring 656 into
 position more securely and: prevents it from twisting, thereby enhancing
 the integrity of the seal.
 The dispensing tower 636 is formed from a plastic body 635 and a metal
 contact ball 637 inserted into a socket 639 formed in the upper end of the
 body 635. As before, the body 635 could be formed from any dimensionally
 stable food-grade material, and preferably is formed from a food-grade
 plastics materials for cost and weight considerations. Polysulfone is
 suitable for these purposes, as is Ultem from General Electric or Vectra
 from Hoechst. The body 635 includes an upper annular shoulder 661 which is
 biased into sealing engagement with the sealing ring 638 via the spring
 642. It also has external channels or grooves 641 in the surface thereof
 that extend at least generally axially from the bottom of the dispensing
 tower 636 to just above the shoulder 633.
 The sealing ring 638 also is similar to the sealing ring 538 of the fifth
 embodiment. It therefore lacks a pronounced sealing lips and seals against
 the valve housing 632 rather than the valve cup 631 when it is in its
 neutral or closed position. The sealing ring 638 also curves inwardly at
 its upper end to form a lip 674 that acts as a stop against which the
 shoulder of the dispensing tower 636 seals when the valve assembly 620
 assumes its neutral or closed position of FIG. 22. An upper stepped
 shoulder 643 of the sealing ring 638 engages a stepped groove 679 in valve
 housing 632 when the valve assembly 620 assumes its neutral or closed
 position. The sealing ring 638 is biased into engagement with the stepped
 groove 679 by spring 644, which rests on a lip 677 of the sealing ring 638
 at its upper end and on an intermediate radial flange 678 of the valve cup
 631 at its lower end. A lower sealing member 645, formed from an inner
 peripheral surface of the lower portion of the sealing ring 638, sealingly
 engages the valve cup 631 as the sealing ring 638 moves downwardly within
 the chamber. The centering studs and/or centering projections of the
 previous embodiments have been eliminated, but could be provided, if
 desired.
 The valve cup 631 of the riser pipe 634 of this embodiment differs from the
 valve cups of the previous embodiments in several respects. For instance,
 in order to permit the use of a larger return spring 644, an upwardly
 extending internal boss 700 is formed in the valve cup 631 to form an
 annular spring chamber 702 that is located beneath the chamber 640 and
 that houses the bottom end of the spring 644. The spring chamber 702 is
 bordered on its inner periphery by the boss 700 and on its outer periphery
 by an outer wall 704 forming the major surface of the valve cup 631. The
 boss 700 also forms a seat for the sealing ring 638. Specifically, an
 inner peripheral surface of the sealing member 645 of the sealing ring 638
 seals against an outer peripheral surface of the boss 700.
 A retainer assembly, provided on the valve cup 631, is configured to
 prevent unintended removal of the valve cup 631 and related components
 (including the dispensing tower 636, the sealing ring 638, and the springs
 642 and 644) from the container 626 prior to container venting and to
 permit removal of these components from the container 626 after the
 container is vented. The retainer assembly preferably is molded integrally
 with the plastic valve cup 631. It is configured to take advantage of the
 elastically deformable nature of the outer wall 704 of the valve cup 631
 to permit the wall 704 to selectively distort radially and
 circumferentially for valve cup insertion or removal.
 In the illustrated embodiment, the retainer assembly includes (1) a
 protrusion 710 that performs ramp and detent functions and (2) a plurality
 (preferably two) centering skids 712 and 714 that help position the
 protrusion 710 for a self threading operation when the valve cup 631 is
 removed from the container 626. The centering skids 712 and 714 and
 protrusion 710 are preferably spaced equidistantly about the periphery of
 the valve cup 631 so that each component of the retainer assembly is
 spaced 120.degree. from the two adjacent components. The three components
 710, 712, and 714 are also staggered vertically from one another so as
 facilitate a self-threading operation during valve cup removal. Hence, the
 top of the protrusion 710 preferably is positioned about 0.005" below the
 top of the first centering skid 712 and about 0.005" above the top of the
 second centering skid 714.
 Referring specifically to FIG. 28, the protrusion 710 includes a detent
 portion 716 and a self-threading ramp portion 718. The detent portion 716
 tapers radially inwardly from an upper end 720 thereof to a lower end 722
 thereof. In the illustrated embodiment in which the clearance between the
 outer peripheral surface of the valve body 631 and an inner peripheral
 surface 627 of the shoulder 628 of the stub 622 is approximately 0.010",
 the upper end 720 of the detent portion 716 has a maximum radial thickness
 of approximately 0.020" at its trailing edge 724. The lower end 722 of the
 detent portion 716 has an effective thickness of zero. This configuration
 permits the valve cup 631 to snap past the shoulder 628 when the valve cup
 631 is inserted into the container 626 but prevents unintended removal of
 the valve cup 631 from the container 626 as detailed below.
 Still referring to FIG. 28, self-threading ramp portion 718 is located
 circumferentially adjacent the detent portion 716 and preferably overlaps
 it to some extent. The ramp portion 718 has a leading edge 726 having a
 thickness of 0.000" and a trailing edge 728 having a thickness of about
 0.020". The leading edge 726 is inclined towards the trailing edge 728
 from an upper end 730 of the ramp portion 718 to a lower end 732 thereof.
 The trailing edge 728 leads to the detent portion 716, which thereby
 doubles as a continuation of the ramp portion 718. The combined structure
 716 and 718 therefore increases generally uniformly in thickness from an
 initial thickness of 0.000" at the leading edge 726 of the ramp portion
 718 to a final thickness of approximately 0.030" at the trailing edge 724
 of the detent portion 716. In the preferred embodiment, (1) the leading
 edge 726 of the ramp portion 718 preferably is curved at a radius of about
 0.520, (2) the detent portion 716 is about 0.250" high by 0.227" wide, (3)
 the self-threading ramp portion 718 is about 0.440" wide, and (4) the
 self-threading ramp portion 718 overlaps the detent portion 716 by about
 0.227" while extending above the detent portion 716 by a height of about
 0.136".
 The centering skids 712 and 714 are virtually identical to one another. The
 discussion that follows therefore will focus on the first centering skid
 712, it being understood that the discussion is equally applicable to the
 second centering skid 714. Referring to FIG. 27, the centering skid 712 is
 essentially rectangular in shape when viewed from its outer radial
 surface. It is about 0.292" high by about 0.095" wide. It varies in radial
 thickness from a maximum of 0.005" at its vertical center portion 734 to a
 minimum effective thickness of 0.000" at each end 736 and 738 thereof. The
 second centering skid 714 differs from the first centering skid 712 only
 that it has a height of 0.282" rather than 0.292", thereby providing the
 above-described staggering effect.
 The insertion and removal of the valve assembly 620 into and from the
 container 626 now be described. Referring to FIG. 31, the valve cup 631 is
 inserted into the container 626 simply by forcing it axially downwardly
 past the shoulder 628 of the stub 622 and into the opening 624 in the
 container 626. During this time, the detent portion 716 of the protrusion
 710 ramps up against the inner peripheral surface 627 of the shoulder 628
 to resiliently deflect the outer peripheral wall 704 of the valve cup 631
 radially inwardly. When the detent portion 716 clears the shoulder 628,
 the valve cup 631 returns to its undeflected position, thereafter
 preventing removal of the valve cup 631 vertically from the container 626.
 The valve cup 631 can then be pushed downwardly to its at-rest position of
 FIGS. 23-25, in which the collar 655 is compressed against the O-ring seal
 656 and the valve cup 631 is held in place by the valve housing 632 and a
 snap ring 740.
 Referring now to FIGS. 32-36, the valve cup 631 and the valve assembly 620
 can be removed from the container 626 by lifting the valve cup 631 toward
 the position seen in FIG. 32 in which the retainer assembly 710, 712, and
 714 engages the shoulder 628 on the stub 622. The valve cup 631 is then
 tilted about its vertical axis as represented by the arrows 750 in FIG.
 32, at which time one of the centering skids 712 engages the upper portion
 of the inner peripheral surface 627 of the shoulder 628 and the other
 centering skid 714 engages the lower portion of the inner peripheral
 surface 627 of the shoulder 628 as seen in FIGS. 34 and 35, respectively.
 At this time, the valve cup 631 is centered in the opening of the
 container 626 and is wedged against the inner peripheral surface 627 of
 the shoulder 628. The operator then twists the valve cup 631
 counterclockwise as represented by the arrows 752 in FIGS. 32, 33, and 36
 while applying vertical lifting forces to the valve cup 631. Because the
 leading edge 726 of the self-threading ramp portion 718 of the protrusion
 710 is wedged against the inner peripheral surface 627 of the shoulder 628
 at this time, this twisting motion causes the shoulder 628 to bite into
 and ramp onto the protrusion 710 in a spiral manner despite the fact that
 the inner peripheral surface 627 of the shoulder 628 is smooth. This
 movement is accommodated by circumferential and radial deflection of the
 outer wall 704 of the valve cup 631. Continued twisting and pulling of the
 valve cup 631 results in continued upward spiral motion of the valve cup
 631 relative to the stub 622 until the detent portion 716 of the
 protrusion 710 clears the top of the shoulder 628 sufficiently to permit
 the valve cup outer wall 704 to return to its undeflected position, after
 which time the valve cup 631, the remainder of the riser pipe 634, and the
 remainder of the valve assembly 620 can simply be lifted vertically out of
 the opening 624.
 It can thus be seen that the releasable retainer assembly formed by the
 protrusion 710 and the centering skids 712 and 71 forms a simple,
 effective mechanism for permitting the controlled insertion of the valve
 cup 631 into the container 626 and removal of the valve cup 631 from the
 container 626. All components of the retainer assembly can be molded
 integrally with the valve cup 631, thereby greatly facilitating
 manufacturing compared to prior known retainer assemblies such as the
 safety mechanism disclosed in the Riis patent. Fabrication is further
 simplified by the fact that no structure need be formed on the shoulder
 628 of the stub 622 for cooperating with the structure-the protrusion 710
 simply self-threads against the smooth inner peripheral surface of the
 shoulder 628.
 The operation of the valve assembly 620 will now be described.
 In the neutral or closed mode, best seen in FIG. 22, dispensing tower 636
 is sealingly urged against sealing ring 638 by the spring 642, and the
 upper seal 643 of the sealing ring 638 is sealingly urged against the
 annular groove 679 by both springs 644 and 642. As a result, and as in the
 previous embodiments, the ingress/egress portals 658 and chamber 640 share
 the same pressure, thereby allowing the liquid in container 626 to seek
 its own level away from portals 658 via the inlet of the riser pipe 634.
 This in turn improves the coupling safety when a coupling arrangement is
 attached to the valve assembly 620.
 As best shown in FIG. 23, when a spindle 690 is inserted into the bore of
 the valve assembly 620 and turned on its axis, it engages a pair of lugs
 (not shown) in bayonet-like fashion in a manner which is, per se, well
 known. The spindle 690 illustrated in FIG. 23 has been custom modified
 from the standard spindle in order to present a cylindrical radially
 centered axial projection 692 on the end of spindle 690. Projection 692
 serves to drive the dispensing tower 636 downwardly against the force of
 second spring 642 to create a valve opening between dispensing tower 636
 and the lip 674 of sealing ring 638 so as to permit the passage of liquid
 through the valve opening, through a number of radial holes 694 in the
 projection 692, and up into the liquid channel (not shown) of spindle 690.
 The spindle 690 also contacts sealing ring 638 as it moves downwardly and
 forces sealing ring 638 downwardly to expose portals 658 to incoming gas.
 During this movement, the lower sealing member 645 of sealing ring 638
 remains in sealing contact with the boss 700 of the valve cup 631 at a
 location beneath ingress/egress portals 658. Gas/liquid separation
 therefore is maintained in the same manner as in the previous embodiments.
 Gas can now enter the container 626 through the portals 658 of valve cup
 631 to push the liquid up the inlet of the integral riser pipe 634,
 between the dispensing tower 636 and the sealing ring 638, and into the
 spindle 690, where the fluid is dispensed from the system in a
 conventional manner.
 The pressure relief mode is illustrated in FIG. 24. In this embodiment, as
 pressure builds on dispensing tower 636 from below, forces generated by
 this pressure are opposed by the retaining forces imposed on the
 dispensing tower 636 by the lip 674. Since sealing ring 638 is made from a
 resilient material such as EPDM or neoprene, the lip 674 deforms to permit
 the dispensing tower 636 to move or "pop" up through the sealing ring 638
 when the gas pressure from within the container 626 reaches a sufficient
 magnitude. This movement exposes the upper openings of channels 641 of the
 dispensing tower 636 to the atmosphere and permits fluid to flow up
 through the channels 641 and out of the bore of the valve assembly 620.
 The upper portion of intermediate radial shoulder 639 on the body 635
 prevents the dispensing tower 636 from completely exiting the valve
 assembly 620 during this process. After excess pressure has been released
 from the container 626, it is necessary to "reset" the valve assembly 620
 by manually or mechanically forcing the dispensing tower 636 back to its
 neutral position beneath the lip 674 of the sealing ring 638.
 8. Advantages of Invention
 The valve assembly according to the present invention, having the
 above-mentioned construction, exhibits several benefits. It can be
 retrofitted to millions of existing containers while at the same time
 using less parts within the same space than previously-known valve
 assemblies. The inventive valve assembly therefore exhibits greater
 cross-sectional ingress and egress areas than previously-known valve
 assemblies, thereby improving fill rates and reducing costs to the users.
 It also can control the internal pressure of a container and is adjustable
 by simply changing the biasing force imposed by springs and/or components
 of the valve assembly. The valve assembly is bi-directional and is able to
 use the same portals for both gas and liquid. In addition, it is able to
 share the same chamber with a gas and a liquid, keeping them separated
 when working, yet together when at rest, so as not to allow liquid to be
 present at coupling transition points. The sealing ring of the valve
 assembly also can maintain perpendicularity and eccentricity with the use
 of a plurality of conical projections and/or vertical ribs fixed to its
 I.D. and/or O.D or even the mating dispensing tower as illustrated in
 FIGS. 9-12 and 17-36. The valve assembly also can control pressure on
 either side of a single movable molded polymer sealing ring. The
 releasable retainer assembly on the valve cup of the riser pipe of the
 embodiment of FIGS. 21-36 facilitates insertion of the valve cup and riser
 pipe into the container while preventing the valve cup and relating
 components of the valve assembly from being forced out of the container
 from pressure within it and still permitting the valve cup to be screwed
 out of the container without having to machine threads on any components
 of the valve assembly.
 Although the invention has been described through its specific forms, it is
 to be understood that various changes and modifications may be imparted
 thereto without departing from the scope of the invention.