GB2217696A - Liquid feed head with multipassage valve seat member - Google Patents

Abstract

A liquid feed head e.g. for feeding beer into cans, includes a valve seat member 63 having a plurality of feed passages 64 formed in a monolithic portion thereof. The feed passages are disposed in a frustoconical skirt portion which is annular in cross section, the skirt portion size controlling the level of filling in the can and ensuring a relatively large head space above the beer to accommodate froth. A valve member 65 is movable relative to the seat member 63 to control the discharge of liquid from reservoir R through the feed passages using counter pressure, valves (V, V2 Figure 4) permitting the can to be connected to a vacuum pump and then to be filled with nitrogen prior to filling with liquid. The cans are fed to work stations of a rotating table by a conveyor wheel (Figure 1), a piston and can arrangement lifting a can on a seat member at a work station into engagement with a seal of a filling head above the station such that the can is positioned within an enclosure carried by the filling head (Figure 3). If the can is filled with a dry commodity, e.g. peanuts, prior to the gas exchanges the liquid filling operation is omitted. <IMAGE>

Description

Title: "Apparatus for packaging" Deseriptial of Invention This invention relates to a liquid feed head particularly, but not exclusively, for feeding beer into a can.

Hitherto such liquid feed head has comprised a valve seat member, a plurality of discrete tubular nozzle members each having a feed passage therein mounted on the seat member and a valve member movable relative to the seat member to control discharge of liquid through the nozzle member.

It has been found that the discrete nozzle members are susceptible to mechanical damage causing irregularities in said feed passages which can cause nucleation of bubbles of gas dissolved in the liquid with consequent undesired loss of gas and/or frothing.

An object of the invention is to provide a liquid fed head in which the above mentioned disadvantages are overcome or are reduced.

According to the present invention we provide a liquid feed head comprising a valve seat member having a plurality of feed passages formed in a monolithic portion thereof.

The feed passages may be disposed in a skirt part of the seat member which extends uninteruptedly around at least part of an arc of a circle and the feed passages being disposed around said circle.

Preferably the skirt part extends around a complete circle and is generally annular in cross-section taken normal to the centre of said circle.

The skirt part may be generally frusto-conical having a larger diameter towards the discharge end of the feed passages.

Each feed passage may have a longitudinal axis which lies in a conical surface containing said circle.

Each feed passage may be inclined in said conical surface relative to a diametric plane thereof containing the axis of the conical surface.

The conical surface may have an included angle of approximately 210 and the feed passages may be inclined to said diametric plane at an angle of approximately 150 The head may comprise a valve member movable relative to the seal member to control discharge of liquid through the feed passages.

An example of the invention will now be described with reference to the accompanying drawings wherein: FIGURE I is aglan view of an apparatus embodying the invention; FIGURE 2 is a cross-section, to an enlarged scale through part of a workstation of the apparatus shown in Figure I and showing a container seat; FIGURE 3 is a further cross-section similar to that of Figure 2 of a different part of the workstation and showing an enclosure member; FIGURE 4 is a cross-section on the line 4-4 of Figure 3; FIGURE 5 is a further- cross-sectional view similar to that of Figure 2 of a further part of the workstation and showing a filling head; FIGURE 6 is a fragmentary section to an enlarged section through the parts shown in Figure 5;; FIGURE óa is an underneath plan view of the part shown in Figure ó; and FIGURE 6b is a side elevation of the filling head shown in Figure 5; and FIGURE 7 a further cross-section similar to that of Figure 2 of a still further part of the workstation and showing an operating ram.

Referring now Figure 1, a work platform 10 is mounted to be driven by a suitable electric motor and drive means II in an anti-clockwise direction as shown in Figure 1. The platform 10 is provided with a plurality of workstations 12 at equally spaced position around its circumference. In this application there are 40 workstations, only one of which is shown.

Also extending around the table 10 adjacent its circumference are three tubular manifolds I3a-I3c connected by pipes l4a-l4c respectively to each workstation 12 as hereinafter to be described. Each manifold, l3a-l3c is connected by a generally radially extending conduit ISa-I Sc respectively to an associated rotary joint 16a-16e so that an appropriate feed to each manifold l3a-I3c is communicated from the appropriate-static supply means hereinofter to be described.

Referring now to Figure 2, each workstation 12 comprises a container support comprising a container seat member 20 having a replacable wear pad 21 and semi-circular upstanding wall 22 which together cooperate to support and locate a container C at the workstation. The seat member 20 is, in the present example, slidably mounted on a boss 22a with a coil compression spring 23 acting therebetween. A roller .24 is rotatably mounted, by means of eccentric arrangement 25, on the seat member 20 and the surface 26 of the roller 24 is adapted to engage a guide surface 27 of a container feed means F (Figure 1) so that the wear plate 21 is correctly aligned with the feed means F as a result of downward depression of the seat member 20 by the roller 24 against the bias of the spring 23.The boss 22a is carried on a piston rod 28 of a two-stage pneumatic ram 29 fixed to the table 10. The ram 29 has bolted thereto a lug 30 from which a pillar 31 projects upwardly and is received in a sliding bearing member 32 connected to the seat member 20 so as to prevent rotation of the seat member 20 relative to the housing of the ram 29 which is fixed to the table 10.

An enclosure base part 35 is slidably mounted on the exterior of the seat member 20 under the influence of a coil compression spring 36 which normally biases the member 35 upwardly. Upward movement is limited by engagement with a shoulder provided at 37.

Referring now to Figure 3 mounted on the table 10 above the container seat member 20 is a filling head 40 having a plurality of liquid filling nozzles 41. The filling head 40 carries a chamber member 42 the lower end of which is adapted for sealing engagement with a sealing washer 38 provided on the base part 35 described hereinbefore. To facilitate this the lower end surface 43 of the chamber member 42 is angled to provide a sharp edge 44 for sealing engagement with the washer 38.

The chamber member 42, as best shown in Figure 4 is provided with four poppet valves VI, V2, at an upper position and N2, Fx, at a lower position.

The valve VI is connected to manifold 13, the valve V2 to manifold 13b and the valve N2 to manifold 13c whilst valve Ex is connected to atmosphere via a filter. All the valves operated in a similar manner to the valve VI and V2 shown in Figure 4. The valve Vl comprises a valve member 46 urged by a coil compression spring 47 against a seat 48 to prevent communication between a passage 49a and a passage 49b. An operating rod 50 of a smaller diameter than the passage 49a extends longitudinally of the passage 49a to a tappet member 51 provided with sealing rings SI a and engaged by a rocker arm 52 pivoted to the member 42 by a pivot rod 53 and carrying a roller 54 for engagement with a cam which encircles the work table 10 and of an appropriate configuration to open and close the valve VI at the desired angular position as hereinafter to be described.

The valve V2 and the other valves operate in an exactly analogous manner and will not be described further.

The passage 49a of the valve VI and the corresponding passages of the other valves intersect a chamber 55 which communicates via apertures 56 with the interior of the chamber member 42.

Referring now to Figure 5, the filling head 40 comprises a bonnet 60 which is carried by the table and has connected thereto, by cap screws 61, a valve seat 62 which has a monolithic frusto-conical skirt part 63 in which are provided a plurality, in the present example 16, of feed passages 64 which provide the nozzles 41. The passages 64 lie in a conical surface having a semi-angle of 210 to the vertical as shown at A in Figure 6 and are inclined in the conical surface at an angle of 1.'0 to a line formed by the intersection of the conical surface with an axial diametric plane thereof, as shown at B in Figure 6. If desired a different number of passages and different angles to those described above may be provided.Mounted within the bonnet 60 is a valve member 65 having a resilient seal 66 thereon which is movable thereby into and out of sealing engagement with a valve seat surface 67 and thus to control flow of liquid through the passages 64. The valve member 65 is carried on a tube 68 which carries a bearing member 69 slidably mounted in a tubular extension 70 of the valve bonnet 60. Adjacent its lower end the tube 68 is fixed to the valve member 65 and has an extension part 71 which is slidably received in a bore 72 in the valve seat member 62. A coil compression spring 73 acts between the bearing member 69 and a shoulder 74 provided within the tubular extension 70 to provide a lifting bias to the tube 68 and hence to the valve member 65.

At its upper end the tube 68 carries a valve 75 which comprises a valve member 76 having a cylindrical skirt 77 which surrounds the tube 68 and guides the valve member 76 for sliding movement thereon. A coil compression spring 78 acts between a shoulder 79 at the lower end of the skirt 77 and a circlip 80 provided on the tube 68. On the opposite side of the valve member 76 is an operating stem 81 having a head 82 and a fork member F receives the stem 81 between the times thereof and can engage the valve member member 76 so as to urge the valve 76 against the end of the tube 68 to close the valve. The fork member can be operated by engagement with a cam surrounding the table at an appropriate position within the cycle of rotation of the station to permit the spring 78 lift the valve member 76 out of sealing engagement with the tube 68.

The tube 68 and extension 70 of the bonnet are provided within a reservoir R of liquid to be fed into the container C with the liquid level being as indicated by the line L-L so that the upper end of the tube 68 is above the liquid level. The reservoir is closed to atmosphere and in the present example is filled with commercially pure nitrogen at a pressure of about 27 psi. Slots 70a are provided in the extension 70 to permit of liquid to pass therethrough.

A passage 82 extends from each passage 64 to an annular recess 84 which is connected by a passage 85 to an annular recess 84a which is connected by a passage 85a to a valve 86 to which nitrogen is fed via.an inlet 86a and which is operated by engagement with a cam at an appropriate position in the cycle of rotation.

Mounted within the part 63 of the valve seat member is a check valve housing 57 which carries a seal member 88 with which a ball closure member 89 is moved into engagement as a result of the ball 89 floating when the liquid level in the container rises so that the ball floats therein.

Referring now to Figure 7, the pneumatic ram 29 comprises a cylinder 90 having a primary piston 91 in sliding and sealing engagement therewith.

The primary piston 91 is connected to the piston rod 18 and mounted within the cylinder 90-for sliding and sealing engagement therewith is a secondary piston 92. An air entry port, not shown, is provided to permit air to act on the underside of the piston P1 I to move the piston 91 and hence the rod 18 upwardly and a further port 93 is provided for exit of air from above the piston 91 during lift. Of course, the supply of air is reversed when it is desired to lower the piston 91. A further port 94 is provided to supply air to act on the upperside of the piston 92. A valve block 95 is provided at the lower end of the cylinder 90 to a control flow of air through the above described ports by virtue of engagement of operating members 96 with a cam around the periphery of the table 10.

Containers C, which in the present example are deep drawn aluminium cans of the type conventionally used today for beer and soft drinks, are fed from a supply to the table 10 by the feed means F which comprises a conveyor 100 to a feed star wheel 101 using a scroll worm to appropriately pitch the containers. The star wheel 101 rotates in a clockwise direction and so feeds cans to the periphery of the table 10 in the same direction as the table is rotating. The wheel 101 is geared to the rotation of the table 10 so that a container C is delivered to a seat member 20 as each workstation passes the wheel 101.

In use, the ram 29 is operated so that the primary piston 91 thereof is at its lowermost position whereby the associated seat member 20 is also in the lowermost position shown in Figure 2. The wheel 24 carried on the seat member 20 can engage surface 27 to ensure that the wear pad 21 is correctly aligned with the feed path of the containers. In practice, it has been found that such an arrangement is not necessary and therefore, if desired, the wheel 24 and associated movable mounting of the seat member 20 can be omitted and the seat member 20 fixed rigidly relative to the piston rod 28.

After a can has been fed onto the seat member 20, the can is carried in a circular path by the rotation of the table 10. As the table rotates the operating members 96 on the lower end of the ram 29 are caused by the associated cam to feed air to act on the underside of the piston 91 to lift the piston rod 18 and hence the seat member 20 and the can carried thereon until the upper end of the piston 91 engages the underside of the piston 92 where movement of the piston 91 is arrested. The position of the piston 92 is determined by the pressure of air, acting on the upperside of the piston 92, fed through the port 94 under the control of the associated valve in the valve block 95. This upward movement of the valve seat is such as to move the base member 35 into sealing engagement with the lower end 43 of the chamber 42.

As a result, the chamber member 42 and the seat member 20 cooperate to form an enclosure E within which the can is disposed. In this condition the upper end of the can is spaced downwardly a short distance e.g. 7 mm from a container seal member S provided on the feed head 40. Thus the interior IC of the container C is in communication with the interior IE of the enclosure E.

The stop member 59 engages the base 61 of the container C to hold the container against the seat member 20 during subsequent operations now to be described. The seat member 20 and member 35 together provide a base part of the enclose E and the spring bias of the member 35 permits of sealing engagement of the enclosure parts 42 and 20 whilst permitting further upward movement of the seat member 20.

After thus disposing the container within the enclosure E continued rotation of the table 10 causes the cam follower roller associated with the valve Vl to engage a portion of the cam which causes the valve Vl to be opened and thus connect the interior of the enclosure to a twoostoge vacuum pump which evacuates the initial atmosphere within the container and enclosure i.e. ambient atmosphere at ambient pressure, and produces a vacuum of approximately 27" of mercury. If desired the vacuum may be higher or lower, for example down to 20" Hg. The system is arranged to achieve this vacuum in a time of 0.4 seconds.Continued rotation of the table then causes the valve VI to close and the valve N2 to open to feed commercially pure nitrogen into the interior of the enclosure E and hence into the interior of the container C to provide a pressure therein of 27 psi. If desired however the pressure may be higher or lower than this for example between 23 psi and 30 psi. The system is arranged so that after initiation of nitrogen feed the desired pressure is achieved in 0.2 seconds.

Continued rotation causes the valve N2 to close and the valve V2 to open to connect the interior of the enclosure to a three-stage vaccum pump to evacuate the nitrogen from the interior of the enclosure and hence from the container and produce a vacuum of approximately 27" of mercury in 0.4 seconds.

Thereafter valve V2 is closed and the valve N2 is again opened to again charge nitrogen into the enclosure and hence into the interior of the container to create the same pressure as before in 0.2 seconds. If desired, of course, nitrogen may be charged to attain a different pressure at this stage.

Thereafter the valve V2 is opened and the valve N2 is closed and the vacuum pumps again evacuate nitrogen from the interior to produce a vacuum of the same extent as the previously again in 0.4 seconds. If desired a vacuum of different extent may be created at this stage.

The valve V2 is then closed and the valve N2 again opened and the interior of the enclosure and the container charged with nitrogen again up to the same or a different pressure in 0.2 seconds.

The valve N2 is then closed and the valve Ex opened and at the same time the second stage of lift of the ram 29 is initiated by permitting air to exit through the port 94 so that the piston 91 and the piston 92 can move upwardly and move the container C into sealing engagement with the container seal S.This condition is shown in Figure 4. In addition the valve 75 is opened to permit nitrogen under pressure from the reservoir P to pass through the tube 68 and hence enter the container C.The sequence is such that the container is brought into initial engagement with the seal S before the pressure in the enclosure E and hence within the container C, has fallen to atmospheric pressure and the valve 75 is opened to apply counter pressure within the container so that as the container is brought fully into sealing engagement with the seal S the full counter pressure is established and the exhaust valve Ex is closed and the nitrogen valve N2 is opened to apply a pressure, below the counter pressure, to the exterior of the container. The pressure above the reservoir R is, in the present example 27 psi and hence the counter pressure within the container C is also 27 psi. The pressure externally of the container within the interior IE of the enclosure E is arranged to be somewhat less than the counter pressure, for example 22 psi.

The counter pressure helps prevent the can deforming whilst it is pressed against the seal S because the cons used are relatively fragile and require the presence of a counter pressure to prevent the neck of the can collapsing out of sealing engagement with the seal S. The pressure on the exterior of the container avoids any significant barrel shaped deformation of the container due to the counter pressure. In addition the apparatus operates more quietly when the container is lowered out of engagement with the seal S as hereinafter to be described.

Because of the relatively high vacuum and rapid extraction of the initial atmosphere and the further atmosphere of nitrogen by the vacuum pumps through the valves VI and V2 there is a tendency for the can to be lifted out of engagement with the seat member 20 hence the provision of the stop 59.

When the counter pressure in the container interior- IC equals the pressure of the liquid in the reservoir R the pressure difference acting on the valve member 60 is solely that arising from the weight of the liquid in the reservoir. This force is less than the force applied by the spring 73 and so the spring 73 lifts the valve member 60 out of sealing engagement to permit liquid to flow through the passages 64 into the container. When the liquid level in the container has risen so that the ball 89 floats, egress of nitrogen through the tube 68 is prevented so that the pressure in the head space above the liquid increases and so creates a back pressure which prevents further flow of liquid.In practice the ball 89 may not remain in sealing engagement with the seal member 88 so that although the main flow of liquid is checked a residual amount of liquid continues to enter the container. The level to which the liquid thus rises depends upon the time interval between initial operation of the check valve and closure. of the valve 75 as a result of table 10 continuing to rotate to cause the cam acting on the fork to close the valve 75 and to move the tube 68 downwardly to mechanically move the valve member 60 to close the passages 64.

Because of the volume of the monolithic skirt part 63 containing in the passages 64, although the level of the liquid may rise to closely adjacent the top of the container whilst the container is in sealing engagement with the seal head, the majority of the volume is occupied by the skirt part 63 and therefore relatively little extra liquid enters the can even though the level may rise significantly above the level of the bottom of the skirt part 63, which is the level at which the check valve is intended to operate.

Accordingly, when the container is lowered the remove the skirt part 63 therefrom, the level of liquid will fall and thus relatively accurate control of liquid level is achieved.

Continued rotation of the table 10 causes the pneumatic ram to lower the can C out of engagement with the seal S. In addition, the carri acting on the valve 86 causes this to be actuated to feed nitrogen under pressure into the passages 64 to force the beer retained in the passages 64 out of the passages and into the can.

The differential pressure acting on the valve member 60 then comprises ambient atmospheric pressure acting on the underside thereof and the pressure in the reservoir R plus the weight of the liquid on the vpper side thereof so that the valve member 60 remains in sealing engagement with the valve seat when the fork member is moved upwardly during the next cycle to open the valve 75 to apply the counter-pressure.

Alternatively, if desired the valve 86 can be connected to atmosphere and, if desired, instead of being connected to the passages 64, may be connected through a separate passage 82a, shown in dotted line in Figure 2, to a space 83 within the frusto conical part 63 of the valve seat member 62.

In this case the cam acts on the valve 86 to connect the space 83 to atmosphere before the can is lowered. After such operation of the valve 86 the differential pressure acting on the valve 60 is as described above and the valve member 60 remains in sealing engagement with the valve seat as described above.

Continued rotation of the table 10 causes the cam acting on the members 96 of the ram 29 to cause the piston rod thereof to be moved downwardly further to lower the seat member 20 to remove the container C from within the enclosure E and then the thus filled container is removed from the seat member 20 in conventional manner and is then fed along a conveyor 102 to a sealing station where a cap is sealed onto the top of the container in a conventional seaming operation.

If desired a dose of liquid nitrogen may be introduced into the liquid in the container prior to sealing the can. As the liquid nitrogen changes to the gaseous state it drives out any ambient atmosphere which may have entered the top of the can after snifting and also provides a pressure above atmospheric pressure within the can during the closing operation thus helping to rigidify the can during this operation and maintain a pressure above ambient atmospheric pressure within the can.

The size of the skirt part 63 is such that it acts as a displacing member of appropriate volume to ensure that there is a relatively large head space above the liquid in the container after the container has been moved out of filling relationship with the filling head and this head space can be used to accommodate any froth created on opening of the container without causing the froth to spill out of the container.

If desired a separate displacing member may be provided carried on the end of a conventional check valve housing 57 such as that shown in dotted line at 58 in Figure 3.

Although in this example there has been described one extraction of ambient atmosphere followed by three introductions of nitrogen with two intervening vacuum extractions if desired a different sequence may be performed. For example there may be a single vacuum extraction of ambient atmosphere and a single introduction of nitrogen. Alternatively there may be a greater number of gas exchanges. If desired a different gas may be introduced at different stages if, for example, it is found that a particular gas is useful at an intermediate stage, for example, to perform a cleaning or similar operation on the interior of the container in any particular application. The pressures and time as mentioned hereinbefore may be varied as desired.

In a modification, not illustrated, for example where a commodity to be packed is a dry commodity such as peanuts the container may be filled to a desired extent with the commodity prior to performing the sequence of gas exchanges. In one such modification the container is filled with the commodity at a position remote from the table 10 and the filled container is fed to the table 10 where the containers are positioned within the enclosures E as described hereinbefore and the gas exchange operation is then performed. Of course the liquid filling operation is omitted. Then the containers are fed to a sealing station. The containers may be provided with a closure such as a screw-threaded lid which may not be fully tightened so thot the gas exchange can take place then the containers may be sealed by tightening the lid.Alternatively another form of sealing means may be provided. If desired means may be provided to permit the sealing operation to be carried out within a desired protected atmosphere which may be of the same atmosphere as that provided within the container. For example instead of providing a liquid filling head in the enclosure a sealing means may be provided within the enclosure.

In a further modification, applicable where the container is sufficienly strong, the above described cycle of gas exchange or any of the modified versions of gas exchange described hereinbefore may be applied directly to the interior of the container without applying the same pressure to th exterior of the container. In one such modification, the apparatus is as described as hereinbefore with reference to the Figures except that the filling head is modified to provide at least one further conduit which is connectable to the valves V I, V2, N2, Ex described hereinbefore so that communication is established directly with the interior IC of the container C and the sequence of gas exchange performed whilst the exterior of the container is subjected to a different pressure, for example, ambient atmospheric pressure. In this case the enclosure is not necessary.

Alternatively, if desired, the exterior of the container may be subjected to a pressure which differs from that in the interior of the container but which is determined to, for example, maintain the shape of the container in a desired configuration. For example, the exterior of the container may be subjected to a pressure below atmospheric pressure of the same or similar vacuum to that created in the interior of the container to prevent inward deformation of the container on application to vaccum to the interior thereof. This vacuum may be continued to be applied when gas such as nitrogen is introduced under pressure to the interior of the container since a thin wall container of the sort typically used for beer or other drinks is copable of withstanding relatively high internal pressures.In this modification the apparatus would be as described hereinbefore but the container would be moved initially into sealing engagement with the seal S and the enclosure would be independently connected to a source of vacuum or such other pressure/vacuum it is desired to apply to the exterior of the container at any particular stage in the pressure cycle applied to the interior valve.

Further alternatively, if desired, the container may be moved directly into engagement with the seal S and the desired sequence of gas exchange with the interior valve performed through the filling head whilst the exterior of the container is subjected to the same sequence of pressure changes by appropriate passages leading from the enclosure interior and controlled by the valves described hereinbefore.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, or a class or group of substances or compositions, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims (10)

CLAIMS:

1. A liquid feed head comprising a valve seat member having a plurality of feed passages formed in a monolithic portion thereof.

2. A head according to Claim I wherein the feed passages are disposed in a skirt part of the seat member which extends uninteruptedly around at least part of an arc of a circle and the feed passages being disposed around said circle.

3. A head according to Claim 2 wherein the skirt part extends around a complete circle and is generally annular in a cross-section taken normal to the centre of said circle.

4. A head according to Claim 3 wherein the skirt part is generally frustoconical having a larger diameter towards the discharge end of the feed passages.

S. A head according to Claim 4 wherein each feed passage has a longitudinal axis which lies in a conical surface containing said circle.

6. A head according to Claim 5 wherein the longitudinal axis of each feed passage is inclined in said conical surfoce relative to a diametric plane thereof containing the axis of the conical surface.

7. A head according to Claim 6 wherein the conical surface has an included angle of approximately 210 and the feed passages may be inclined to 0 said diametric plane at an angle of approximately IS

8. A head according to any one of the preceding claims wherein the head comprises a valve member movable relative to the seat member to control discharge of liquid through the feed passages.

9. A head substantially as hereinbefore described with reference to the accompanying drawings.

10. Any novel feature or novel combination of features disclosed herein andlor shown in the accompanying drawings.