GB2190467A - Improvements in or relating to moulding - Google Patents

Abstract

Moulding apparatus includes a filling head 1 for evacuating and filling a mould 3 with plaster of paris. The filling head 1 includes a valve 2 with three inlets 15, (19) and (20) connected to evacuating means, a supply of plaster of paris and a supply of cleaning water respectively. Inlet ports in a valve seat 5 are selectively aligned with a port 14 in a valve member 6 by rotation of the member 6 or, in the modification of Figure 7, by rotation of the valve seat 5. The filling head is translatable to a waste disposal (25) where it is flushed with cleaning fluid between successive filling operations. The inlet channel defined by the valve components is of cylindrical shape so that the valve may be readily purged of any solidified obstruction by flushing through the valve gate into the waste disposal. The apparatus has particular application in the moulding of casts having fine detail. As shown in Figure 9, each inlet port may be surrounded by a resilient sealing ring 77 which is recessed both on the surface contacting the valve member 6 and on its lateral surfaces. <IMAGE>

Description

SPECIFICATION Improvements in or relating to moulding This invention relates to moulding and in particular to a valve for dispensing in a flowable form a product which cures to a non flowable form and to a moulding process in which a sequence of moulds are filled from a filling head.

It is known for sculptured ornaments and the like to be reproduced byfiiling a rubber mould with liquid plaster of paris for example which solidifies in the shape ofthe mould. One problem associated with this process is thatfine detail of the mould can trap air bubbles which result in imperfections in the resulting cast.

Afurtherproblem is that a quick setting product such as plaster of paris is difficultto dispense by any automatic apparatus since the apparatus will be prone to obstruction due to the solidification ofthe product.

According to the present invention there is disclosed a valve for dispensing in a flowable form a product which cures to a non flowableform comprising a valve member and a valve seat which are relatively moveable in sliding contact with one another, a plurality of inlet passages communicating with inlet ports in the valve seat, the valve member having a gate such that in an open condition ofthe valve the gate is aligned with a selected inlet port thereby establishing a flow path through the valve along a channel comprising the selected inlet passage and the gate, the shape of the channel being such that a non flowable mass ofthe product formed therein will pass through the gate when the valve is purged by a flow of cleaning fluid.

Preferably the channel is cylindrically shaped such that any non flowable mass formed in the channel may be purged as a cylindrical block via the gate.

Preferably the valve member and the valve seat are relatively rotatable and the gate is spaced radially from the axis of rotation, and inlet ports being angularly spaced about the axis whereby the gate may be aligned with selected inlet ports by relative rotational movement between the valve member and the valve seat.

Preferably the angular spacing between adjacent ports provides intermediate relative positions ofthe valve member and valve seat at which the inlet ports are sealed to thereby close the valve.

According to one aspect ofthe invention there is disclosed a valve wherein the valve member is non rotatably mounted and the valve seat is mounted on an axle connected to drive means for rotation ofthe valve seat. Preferably in such a valve, each inlet port has a respective port seal being annular and elastomericand located in an annulargroove in the valve seat so as to surround the respective inlet port, each of the port seals being maintained in sealing slidable contact with a planar contact surface ofthe valve member.

Preferably each such port seal includes an annular re-entrant face comprising an annular recess bounded by inner and outer annu lar projections, which projections are presented in spaced apart contact with the valve member to resist rolling motion of the seal during rotation of the valve seat.

Advantageously each port seal includes radially inner and outer sidefaces extending generally at right angles to the contact surface of the valve member, each ofwhich faces is recessed.

Conveninentlythevalve includes inner and outer peripheral seals each being concentric with the rotation axis and sealingly operable between the valve seat and valve member,the inner and outer peripheral seals being radially spaced and the contact surface been located therebetween.

Conveniently the valve member comprises an annular rib projecting axiallytherefrom with respect to the rotation axis, which rib defines an annular surface in a radial plane constituting the contact surface and bounded by inner and outer ribwalls, the rib being received in a co-operating annular channel of the valve seat and the inner and outer peripheral seals being co-operable with the inner and outerribwalls respectively.

According to an alternative aspect ofthe present invention there is disclosed a valve wherein the valve seat is non rotatably mounted and the valve member is connected to drive means for rotation of the valve member. Advantageously in such a valve the drive means is operable in a fixed direction of rotation to bring the gate into alignment with selected inlet ports in a predetermined sequence which is repeatable at each cycle of rotation.

According to a further aspect of the present invention there is disclosed a moulding process in which a sequence of moulds are filled from afilling head including the steps of evacuating airfrom a mould and then dispensing a flowable product so as to fill the mould wherein both the evacuation ofair and dispensing of product are effected through a common valve ofthefilling head and which process includes the further step of purging the valve with a cleaning fluid priorto evacuation ofthe next mould in the filling sequence.

Advantageouslythe steps of evacuation and dispensing are carried out at a first location ofthe filling head and the step of purging the valve is carried out at a second location, the process including the further steps of translating the filling head between the first and second locations before and after purging of the valve.

Alternatively the steps of evacuation, dispensing and purging are carried out at the same first location and include the further steps oftranslating a waste disposal means into and out of engagement with the filling head at the first location before and after the step of purging the valve respectively.

Preferably in any such moulding processthefilling head valve comprises a valve as herein before disclosed and having three inlets connected to an evacuating means, a product supply means and a cleaning fluid supply means respectively.

Advantageously the process includes a further step of periodically purging the product supply means with a cleaning fluid through the valve with the filling head engaged with the waste disposal means.

According to a further aspect of the invention there is disclosed apparatus for use in a method as hereinbefore disclosed comprising a filling head having a valve, mould engaging means at a first location for bringing into and out of engagement a mould and the filling headsoastoencloseavolume to be evacuated and filled, evacuating means connected to a first inlet passage of the valve, product supply means connected to a second inlet passage of the valve, cleaning fluid supply means connected to a third inlet passage of the valve, waste disposal means for disposing of waste purged from the valve and translating means for relative translational movement between the filling head and the waste disposal means for bringing into and out ofengagementthe filling head and the waste disposal means.

Conveniently the translating means is operable to translate the waste disposal means relative to the stationaryfilling head.

Preferably the waste disposal means comprises means forwiping a surface of the valve and spraying the valve with cleaning fluid.

Alternatively the translating means may be operable to translate the filling head relative to a stationary waste disposal means.

Preferably such apparatus further includes conveyor meansfor conveying a sequence of empty moulds to the mould engaging means and removing filled mouldstherefrom.

Particular embodiments of the invention will now be described byway of example only and with reference to the accompanying drawings of which: Figure lisa sectional elevation of a filling head having a valve with a rotatable valve member and engaged with a mould, Figure2 is an elevation of apparatus including the filling head of Figure 1 showing the filling stage, Figures a similarview of the apparatus of Figure 2 showing the valve purging stage, Figure 4 is a similar view of the apparatus of Figures 2 and 3 and the completion of a cycle with the filling head disengaged from a mould, Figure 5shows a sectional view of a valve seat in the direction of arrows 5-5 of Figure 1, Figure 6shows a sectional view of a valve member in the direction of arrows 6-6 of Figure 1, Figure 7shows a sectional elevation of an alternative filling head having a valve with a rotatable seat and engaged with a mould, Figure 8 is a view ofthe underside of the valve seat of the valve of Figure 7, Figure 9 is an enlarged detail showing an inlet port seal of the valve of Figure 7, and Figure 10 shows an alternative apparatus in which the waste disposal means is translatable with respectto afixedfilling head.

The filling head 1 of Figure 1 has avalve2 and is shown in engagement with a silicone rubber mould 3supported beneath the filling head in a mould support nest 4. The valve 2 includes a valve seat 5 which is in sliding contact with a valve member 6 which is rotatable by means of an axle 7 extending through a vertical bore 8 in the valve seat. A spring 9 is held in compression between a boss 10 on the axle 7 and the upper surface ofthe valve seat such thatthe valve seat and valve member 6 are biassed into contact.

As shown in plan view in Figure Sthevalve seat is circular and includes first, second and third inlet ports 11,12and 13respectively.Asshown in plan in Figure 6the valve member6 is a circular disc of smallerdiameterthan the valve seat 5 and inciudesa single gate 14 comprising a circularaperture,the arrangement being such that by rotation ofthevalve member6the gate may be brought into alignment with the first, second orthird inlet ports 11,12 or 13 respectively. In Figure 1 the valve member 6 is shown with the first inlet port 11 in alignment with the gate 14.

A corresponding inlet passage is associated with each ofthe inlet ports and in Figure 1 a first inlet passage 15 is shown extending through the valve seat 5 so as to define a channel (15,11,14) comprising the inlet passage, inlet port and gate which communicates through the filling head to the mould 3. A pipe 16 connects the first inlet passage 15 with an evacuating means (not shown ) such as a rotary vacuum pump.

A base plate 17 extends parallel to and spaced from the valve seat 5 such that the valve member 6 is slideable therebetween with the base plate including three outlet ports 18 in alignment with the inlet ports of the valve seat. Each outlet port 18 tapers in a direction towards the valve member 6.

The second inlet passage 19 is connected to a product supply means (not shown) which provides a suppiyof plasterof paris in liquid form. Thethird inlet passage 20 is connected to a cleaning fluid supply means (not shown) which supplies a cleaning fluid such as water under pressure.

The filling head 1 is suspended from a translating means 21 forhorizontallytranslatingthefilling head between a first location 22 where the filling head is engageable with a mould engaging means 23 and a second location 24 at which the filling head is engageable with waste disposal means 25. The mould engaging means 23 includes a ram 26 for raising a mould carrier 27 and there is also afurther ram 260 for lowering thefilling head 1 to bring the mould 3 into contact with the filling head 1 as shown in Figure 1. Aconveyor28 is arranged to carry a numberofmould carriers 27 around a closed path such that empty moulds are conveyed to thefilling head and filled moulds are conveyed away from the filling head.

In Figure 5thefilling head is shown at the second location 24 at which a waste disposal means 25 is located underneath the filling head. The waste disposal means comprises a funnel 29 through which waste flushed from the filling head together with cleaning fluid is conducted and also includes water spray nozzles 30 for use in washing the undersideofthefilling head.

In Figure 4the filling head 1 is shown atthefirst location 22 immediately on return from the second location and before the filling head 1 and mould engaging means 23 are brought into engagement.

The valve 2 operates by aligning the gate 14with successive inlet passages 15, 19 and 20 and is rotated by drive means 31 to successive angular positions as required.Thevalve is open when the gate 14is aligned with a selected inlet passage and is closed at intermediate positions of the gate. By stepping the valve member 6 in a constant direction the inlet ports are selected in a predetermined sequence which is repeatable at each cycle of rotation.

The sequence of events during the moulding of plaster of paris casts begins with the mould engaging means 23 being brought into engagement with thefilling head 1 with an empty mould 3 held in sealing contact with the base plate 17. As shown in Figure 1 the valve member is then rotated until the valve is in the open position at which the first inlet port 11 is aligned with the gate 14 and the evacuating means is connected to the mould through the pipe 16, the first inlet passage 1 5,thefirst inlet port 1 1,the gate 14, and the corresponding port of the three outlet ports 18 in the base plate. After a sufficient time period forthe airwithin the mould to be evacuated the valve member 6 is rotated by means of the drive means 31 which rotates the axle 7 until the gate 14 is aligned with the second inlet port 12.In this position plaster of paris from the product supply meansflowsthroughthechannelcomprisingthe second inlet passage 19, the second inlet port 13, the gate 14 and the corresponding outlet port 18 into the mould 3. After a sufficienttime has elapsed forthe mouldto become completely filled the valve member 6 is again rotated with the gate 14 coming to rest intermediate the second and third inlet ports 13 and 14 respectively such that the valve is in a closed state.

The filling head 1 and the mould engaging means 23 are then separated vertically by action of the ram 26 and 260 and the filling head is translated from the first location into engagement with the waste disposal means 25 at the second location 24 as shown in Figure 3. The valve member 6 is again rotated until the gate 14 is in alignment with the third inlet port 14 and cleaning fluid then flowsthrough thethird inlet passage 20,thethird inlet port 13,the gate 14 and the corresponding outlet port 18 so asto flush any residual plaster of paris into the funnel 29 of the waste disposal means 25. At the sametime water is sprayed from the spray nozzels 30 to cleanse the underside ofthe base plate 17 and the remaining outlet ports 18.

The valve member 6 is then rotated to place the valve in a closed position with the gate 14 intermediate the third and first inlet passages 20 and 15 respectively and after allowing the cleaning fluid todrainthefilling head 1 isthentranslatedfromthe secondtothefirst location 22. Duringthecleansing operation at the second location the filling head 1 may be lowered by means ofthe ram 260 into proximity with the spray nozzles 30 and subsequently raised prior to translation.

The previously filled mould is removed by the conveyor 28 and a new empty mould 3 placed in the mould engaging means 23. Afterthe mould engaging means and filling head are brought into engagement by action of the ram 26 the valve member6 is again rotated to align the gate 14with the first inlet passage 15 to evacuate the new mould and begin the cycle ofthe process once again. Atthis stage those parts of the filling head 1 through which air is evacuated will be free of any trace of plaster of paris sincethese will have been purged whilst engaged with the waste disposal means 25 thereby avoiding the problem of contamination reaching the vacuum pump.

This cycle of events may be varied after a number of moulding cycles by the addition offurthersteps whilst the filling head is engaged with the waste disposal means 25 in which the gate 14 isaligned with the second inlet port 12 and the product supply line isflushed with a suitable cleaning fluid to thereby avoid the problem of solids builing up in this supply line. Flexible plastic pipes ofthe supply line may be replaced where the contamination is particularly severe. The shape ofthe channel within the valve through which the plaster of paris is to be flushed is such that a solidified mass of plaster of paris will pass through the gate at sufficient pressure of cleaning fluid. The taper provided in the outlet ports 18 prevents any obstruction to the passage of this mass through the base plate 17.

By evacuating the mould priortofilling,the problem of air bubbles being trapped in the mould is avoidedsothatthecompletelyfilled mouldwill produce a cast which is free of imperfections.

The sequence of events in the process may conveniently be controlled automatically by a central control circuit (not shown) and the relative angular position ofthe gate 14 and the inlet ports 12,13 and 14 is then conveniently controlled by using a drive means which comprises a stepping motor.

The product supply means uses a peristaltic pump for bringing plastertothe mould through a length of plastic pipe. This type of pump has the advantage that no moving parts come into contact with the productandtheonlypartwhichcan be damaged by setting plaster is the length of plastic pipe which can easily be replaced.

An alternative type of valve is shown in Figures 7 to 9 in which corresponding reference numerals have been used to those appearing in Figures 1 to 6where appropriate.

The alternative valve 50 of Figure 7 has a rotatable valve seat 55 and a non rotatable valve member 56.

The valve member 56 comprises a horizontal plate 57 having a lower surface 58 to which a mould 3 is presented for evacuation and filling via a flared port 18 formed in the lower surface. The upper surface 59 of the valve member 56 extends horizontally with an annular rib 60 of rectangular cross section projecting upwardly therefrom and having an upper surface 61.

The rib 60 has radially inner and outer rib walls 62 and 63 respectively which extend vertically and each inciude circumferential grooves 64 and 65 respectively at approximately two thirds of their height. Innerand outer 0 ring seals 66 and 67 respectively are received in the grooves 64 and 65.

The valve seat 55 is circular and overlays the valve member 56so as to be concentric with the circular rib 60. Thevalve seat 55 has an annular channel 68 which is conformal in cross section to the rib 60 such thatthe inner and outer ring seals 66 and 67 make sealing contact with inner and outer sidewalls 69 and 70 of the channel.

The valve seat 55 is fixedly connected to a central axle 7 which is connected to a drive means 31 for rotation of the valve seat.

As seen in Figure 8 which is an underneath view of the seat 55, the valve seat includes first, second and third inlet passages 15, 19 and 20 which are of circular cross section and are angularly spaced within one half of the channel 68. An arcuate groove 71 extends approximately semi-circularly within the remaining half of the channel and co-operates with a detent 72 projecting upwardly from the valve member 56 to iimit the a ngu lartravel of the valve seat 55.

The inlet passages 15, 19 and 20 form first, second and third inlet ports 1 1, 12 and 13 respectively in the annular surface 73 formed within the channel 68 and the ports 11,12 and 13 are surrounded by circular grooves 74,75 and 76 respectively. Within each such groove74,75 and 76 is located an annularseal 77 as shown in enlarged detail in Figure 9. The seal 77 has an annular re-entrantface 78 comprising a recess 79 bounded by annular projections 80 which projections are presented in contact with the upper surface 61 ofthe rib. The seal 77 has radially inner and outer sidefaces 81 and 82 which are also recessed.Each groove74,75 and 76 is tapered outwardly so as to retain the respective seal 77 in position when for example the valve member and valve seat are separated during servicing for example.

The upper surface 61 of the rib serves as a contact surface against which the seals 77 make sealing contact.

The first, second and third inlet passages 15, 19 and 20 respectively are connected by flexible pipes 16to evacuating means, product supply means and cleaning fluid supply means respectively.

The valve member 56 includes a gate 14 communicating with the outlet port 18, the gate comprising a cylindrical bore of equal diameter to the inlet passages 15, 19 and 20 and three alternative open positions ofthe valve 50 are available in which a respective inlet port is aligned with the gate 14. As seen in Figure 7, in any such open position ofthe valve a flow path is established through the valve along a channel comprising the selected inlet passage and the gate, the shape of the channel being cylindrical and of constant cross section other than for a flared enlargement of the outlet port 8.

The inlet passages 15,19 and 20 are angularly spaced sufficiently to provide intermediate positions of the valve seat 55 at which the gate 14 is exposed only to parts of the annular surface 73 which are external to the seals 77. Similarly in any such closed position the inlet passages 15,19 and 20 are obturated by the upper surface 61 of the rib 60 and sealing action ofthe seals 77.

Each seal 77 is prevented from rolling within its respective groove 74,75,76 during rotation ofthe valve seat by virtue of the re-entrantface 78 and projections 80 which give stability during sliding relative to the upper surface 61 of the rib 60 particularlyforthose portions of the seal which extend at an angle to the direction oftravel. It has been found that the use of such a seal 77 is particularly effectIve in wiping any residual plaster from the uppersurface 61 whilst also providing an effective vacuum seal in the case of inlet passage 15.

In the case of inlet passages 19 and 20 which are subject two fluid pressure of product and cleaning fluid respectively the recessed inner side face 81 of the seal 82 serves to deflectthe seal under applied fluid pressure into positive contact with the upper surface 61.

The need to limitthe extent of angulartravel of the valve seat 55 arises from the connection ofthree flexible pipes 16 to the valve seat so that continued rotation in a constant direction would result in fouling ofthepipes.Thefirstinletpassage 15to which the evacuating means is connected is positioned intermediate the second and third inlet passages 19 and 20 respectively so that during a complete cycle of the valve actuation the sequence of open positions ofthe valve corresponds to the first, second, first and third inlet passages respectively been connected to the gate 14.

The alternative valve 50 may be incorporated in a filling head of an apparatus as described above for use in moulding of plaster of paris casts. The method of moulding described above with respectto the valve 2 equally well be used with the alternative valve 50 provided account is taken of the need to reciprocate the drive means instead of providing rotational drive in a consta nt direction. The alternative valve 50 provides improved vacuum sealing and removes the need for a spring bias between the valve seat and valve member.

The moulding apparatus described above with reference to Figures 1 to 6 or as modified by including an alternative valve 50 as shown in Figures 7 to 9 may alternatively include a waste disposal meanswhich istranslatable into and out of engagement with the filling head at the first location.

In such an arrangement the evacuation, dispensing and purging ofthe valve are all carried out at the same first location.

An example of such an arrangement is shown in Figure lOin which a valve 50 ofthetype shown in Figure 7 is engaged by a waste disposal means 100 comprising a tray 101 extending beneath the valve 50 and having a lip 102 in close proximity with the lower surface 58 of the valve.

The tray 101 is translatable horizontally into and out of engagement with the valve 50 after separation ofthe valve from the mould. The waste disposal means 100 is provided with a spray nozzle 103for directing a jet of cleaning fluid onto the valve and the tray is positioned so as to collect any waste flushed through the outlet port 18. Awiper blade 104 extends upwardly into contact with the lower surface 58 and serves to clean the surface during translational movement of the tray 101.

Alternative forms of valves are also envisaged within the scope ofthe present invention in which relative movement between the valve seat and valve member is linearwith inlet ports being arranged in linear array. A reciprocating linear motion would then provide a cycle of opening and closing the valve as required.

Alternatively where a rotatable valve seat is incorporated in the valve, the valve seat and valve member may be planar without including a co-operating rib and channel provided alternative means are included for rotational alignment ofthe valve seat.

Claims (23)

1. A valve for dispensing in a flowable form a productwhich cures to a nonflowableform comprising a valve member and a valve seat which are relatively moveable in sliding contact with one another, a plurality of inlet passages communicating with inlet ports in the valve seat, the valve member having a gate such that in an open condition ofthe valve the gate is aligned withaselected inletport thereby establishing a flow path through the valve along a channel comprising the selected inlet passage and the gate, the shape of the channel being such that a non flowable mass ofthe product formed therein will pass through the gate when the valve is purged by a flow of cleaning fluid.

2. Avalve as claimed in claim 1, wherein the valve member and the valve seat are relatively rotatable and the gate is spaced radially from the axis of rotation,the inlet ports being angularly spaced aboutthe axis whereby the gate may be aligned with selected inlet ports by relative rotational movement between the valve member and the valve seat.

3. Avalve as claimed in claim 2 wherein the angular spacing between adjacent ports provides intermediate relative positions of the valve member and valve seat at which the inlet ports are sealed to thereby close the valve.

4. Avalve as claimed in any of claims 2 and 3 wherein the valve member is non rotatably mounted and the valve seat is connected to drive means for rotation of the valve seat.

5. Avalve as claimed in claim 4 wherein each inlet port has a respective port seal being annular and elastomeric and located in an annular groove in the valve seat so asto surround the respective inlet port, each ofthe port seals being maintained in sealing slidable contactwith a planar contact surface of the valve member.

6. Avalve as claimed in claim wherein each port seal includes an annular re-entrant face comprising an annular recess bounded by inner and outer annular projections,which projections are presented in spaced apart contact with the valve memberto resist rolling motion of the seal during rotation of the valve seat.

7. A valve as claimed in claim 6 wherein each port seal includes radially inner and outer side faces extending generally at right angles to the contact surface ofthevalve member, each of which faces is recessed.

8. Avalve as claimed in any of claims 5 to 7 including inner and outer peripheral seals each being concentric with the rotation axis and sealingly operable between the valve seat and valve member, the inner and outer peripheral seals being radially spaced and the contact surface being located therebetween.

9. Avalveasclaimed in claim 8 wherein thevalve member comprises an annular rib projecting axially therefrom with respect to the rotation axis, which rib defines an annular surface in a radial plane constituting the contact surface and bounded by innerand outer rib walls, the rib being received in a co-operating annular channel ofthe valve seat and the inner and outer peripheral seals being co-operablewiththeinnerandouterribwalls respectively.

10. Avalveasclaimed in anyofclaims2and3 wherein the valve seat is non rotatably mounted and thevalve member is connectedto drive meansfor rotation of the valve member.

11. A valve as claimed in claim 10 wherein the drive means is operable in a fixed direction of rotation to bring the gate into alignment with selected inlet ports in a predetermined sequence which is repeatable at each cycle of rotation.

12. A moulding process in which a sequence of moulds arefilled from a filling head including the steps of evacuating airfroma mould and then dispensing a flowable product so asto fill the mould wherein both the evacuation of air and dispensing of product are effected through a common valve of the filling head and which process includes the further step of purging the valve with a cleaning fluid priorto evacuation of the next mould in the filling sequence.

13. A moulding process as claimed in claim 12 wherein the steps of evacuation and dispensing are carried out at a first location ofthe filling head and the step of purging the filling head valve is carried out at a second location with the filling head in engagement with a waste disposal means at the second location, the process including the further steps oftranslating the filling head between the first and second locations before and after purging of the filling head valve.

14. A moulding process as claimed in claim 12 wherein the steps of evacuation, dispensing and purging are carried out at the same first location and including the further steps of translating a waste disposal means into and out of engagement with the filling head at the first location before and afterthe step of purging the valve respectively.

15. A moulding process as claimed in either of claims 13 and 14whereinthefilling head valve comprises a valve as claimed in any of claims 1 toll and having three inlets connected to an evacuating means, a productsupply means and a cleaning fluid supply means respectively.

16. Amoulding process as claimed in claim 15 including the further step of periodically purging the productsupplymeanswith acleaningfluid passing out through the valve with the filling head engaged with the waste disposal means.

17. Apparatus for use in a process as claimed in anyofclaims 14to 16 comprising afilling head having avalve, mould engaging meansatafirst location for bringing into and out of engagement a mould and thefilling head so asto enclose avolume to be evacuated and filled, evacuating means connected to a first inlet passage of the valve, productsupply means connectedto a second inlet passage of the valve, cleaning fluid supply means connected to a third inlet passage ofthe valve, waste disposal means for disposing of waste purged from the valve and translating meansforrelative translational movement between the filling head and the waste disposal means for bringing into and out of engagementthe filling head and the waste disposal means.

18. Apparatus as claimed in claim 17 wherein the translating means is operable to translate the waste disposal means relative to the stationary filling head.

19. Apparatus as claimed in claim 18 wherein the waste disposal means comprises means forwiping a surface of the valve and spraying the valvewith cleaning fluid.

20. Apparatus as claimed in any of claims 17 to 19 including conveyor means for conveying a sequence of empty moulds to the mould engaging means and removing filled moulds therefrom.

21. Avalve substantially as herein before described with reference to and as shown in any of the accompanying drawings.

22. Apparatus substantially as hereinbefore described with reference to and as shown in any of the accompanying drawings.

23. A moulding process substantially as hereinbefore described with reference to and as shown in any of the accompanying drawings.