Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
APPARATUS FOR METERING FLUIDS
Document Type and Number:
WIPO Patent Application WO/2000/068078
Kind Code:
A1
Abstract:
Apparatus for filling cartons with a thick liquid, such as yoghurt, which may contain solid particulates, such as pieces of fruit, comprises a metering valve (10) connected by a port (14) to a pump whereby the liquid is sucked into the valve (10) through an inlet port (12) and then discharged through an outlet port (13). The alternate opening and closing of the inlet (12) and outlet (13) ports is controlled by shoes (15, 16) of a valve member (18) which is given oscillating rotary motion by an actuator (31). A pinion (30) non-rotatably fixed to the valve member shaft (18) is oscillated by racks (42, 43) reciprocated by pistons (34, 35) under the control of a five-port pneumatic valve (26). In accordance with the invention the valve member (18) is also moveable to a third position in which none of the ports (12, 13, 14) is obturated by the shoes (15, 16) to enable the valve (10) to be flushed with cleaning fluid. The inner surface (23) of the valve body is frusto-conical and the valve member (18) can be displaced axially to take the shoes (15, 16) out of contact with said inner surface (23) during the cleaning process. In a modification the shoes (15, 16) are replaced by a circumferentially apertured annulus.

Inventors:
Davies, Peter Owen (19 Tainui Road, Cockle Bay, Auckland 1006, NZ)
Application Number:
PCT/NZ2000/000070
Publication Date:
November 16, 2000
Filing Date:
May 10, 2000
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
Davies, Peter Owen (19 Tainui Road, Cockle Bay, Auckland 1006, NZ)
International Classes:
B65B3/32; G01F11/44; (IPC1-7): B65B3/32; B67C3/28; F16K11/076
Foreign References:
EP0959005A2
DE3838462A1
EP0492928A1
Attorney, Agent or Firm:
Piper, James William (Pipers, Unicorn House 300A Richmond Roa, Grey Lynn Auckland 1002, NZ)
Download PDF:
Claims:
CLAIMS:
1. Apparatus for metering fluids which may contain particulate matter, the apparatus comprising a valve body (11) having an inner surface (23) of circular section penetrated by at least three circumferentially spaced apart ports (12,13,14), two of which are respectively an inlet (12) and an outlet port (13) and a valve member (18,15,16,61), characterised in that means (31) is provided for rotatably moving the valve member (18,15,16,61) within the valve body (11) between first and second positions in which the valve member alternately opens one of said inlet and outlet ports (12,13) while closing the other said outlet and inlet port (13,12), and that means (25) is provided for producing a pressure difference at the remaining port (14) or ports whereby in use a fluid will be sucked into the valve body (11) through the inlet port (12) and expelled from the valve body (11) through the outlet port (13), the valve member (18,15,16,61) being selectively moveable in the valve body (11) to a third position in which none of the ports (12,13,14) is obturated by the valve member (18,15,16,61).
2. Apparatus as claimed in claim 1, characterised in that said ports (12,13,14) are three in number, said remaining port (14) communicating with a pump (25) which alternately applies suction and pressure to the interior of the valve body (11).
3. Apparatus as claimed in claim 1 or claim 2, characterised in that the inlet (12) and outlet (13) ports are respectively at the top and bottom of the valve body (11), a single remaining port (14) penetrating the valve body (11) generally horizontally.
4. Apparatus as claimed in any one of the preceding claims, characterised in that the valve member (61) is an annulus formed with circumferentially spaced apertures (72,73,74,83) each of which will open a port (12,13,14) when aligned therewith, a port (12,13,14) being closed when no said aperture (72,73,74,83) is aligned therewith.
5. Apparatus as claimed in any one of claims 13, characterised in that the valve member comprises a rotatable shaft (18) from which arms extend radially in angularly spaced relation, each arm bearing at its distal end a shoe (15,16) the radially outer surface of which is shaped complimentarily to the inner surface (23) of the valve body (11).
6. Apparatus as claimed in claim 5 as appendant to claim 3, characterised in that said arm and shoe (15,16) assemblies are two in number and adopt on the shaft (18) a position approximately corresponding to the hands of a clock in the 5 o'clock position.
7. Apparatus as claimed in claim 5 or claim 6, characterised in that the shoes (15,16) are spring loaded on the arms to be urged into contact with the inner surface (23) of the valve body (11).
8. Apparatus as claimed in any one of the preceding claims, characterised in that the inner surface (23) of the valve body (11) is frustoconical, the surface (s) (15,16,60) of the valve member presented to said inner surface (23) having a complimentary shape, and wherein means (76) is provided whereby the valve member (18) may be displaced axially relative to the valve body (11) thereby to move the valve member (15,16,60) out of contact with the inner surface (23) of the valve body.
9. Apparatus as claimed in claim 8 as appendant to claim 7, characterised in that means (57,70) is provided to limit the extension of each shoe (15,16) from the associated arm when the valve member (18) is move axially away from the valve body (11).
10. Apparatus as claimed in claim 9, characterised in that the said means comprises an arcuate extension of each shoe (15,16) into a cylindrical extension (70) of the valve body (11), said extensions cooperating to limit the radially outward movement of the shoes (15,16) relative to the arms.
11. Apparatus as claimed in any one of the preceding claims characterised in that it further comprises an actuator (31) for imparting oscillating rotational movement to the valve member (18,60), the acuator comprising a pinion (30) nonrotatable relative to the valve member (18) and a pair of racks (42,43) on opposite sides of the pinion (30), means (34,35) being provided for oppositely longitudinally displacing the racks (42,43) to impart oscillating rotary movement to the pinion (30).
12. Apparatus as claimed in claim 11, characterised in that said means for oppositely displacing the racks (42,43) comprises a piston (34,35) connected to each rack, each piston (34,35) being displaceable in a cylinder (36,37) in response to unequal fluid pressures in a cylinder (36,37) at opposite ends of the piston (34,35) therein.
13. Apparatus as claimed in claim 12, characterised in that the unequal fluid pressures are produced by pneumatic apparatus (26) which alternately vents the ends of each cylinder (36,37) while supplying air under pressure to the cylinder (36,37) at the opposite end of the piston (34,35) therein.
14. Apparatus as claimed in claim 12 or claim 13, characterised in that means (52) is provided for selectively lengthening the stroke of one of the pistons (34,35) in the associated cylinder (36, 37) thereby to rotate the valve member (18) to said third position thereof.
15. Apparatus as claimed in claim 14 as appendant to claim 13, characterised in that a larger piston (52) is moveable in an enlargement (50) of one of said cylinders (36) at one end of the smaller, firstmentioned piston (34) therein, said enlargement being normally supplied with air under pressure on the side of the larger piston (52) remote from the smaller piston (34) thereby to limit the stroke of the smaller piston (34), said enlargement (50) being vented when it is desired to move the valve member (18) to said third position thereof thereby to lengthen the stroke of the smaller piston (34).
16. Apparatus as claimed in any one of the preceding claims, characterised in that means (68,71,75,76,78) is provided for displacing the valve member (18) axially between operative and cleaning positions.
17. Apparatus as claimed in claim 16 as appendant to any one of claims 1115, characterised in that said means comprises pistons (69,76) at opposite ends of the valve member (18), one (76) of said pistons being moveable in a cylinder (75) within the shaft of the pinion (30) of the actuator.
18. Apparatus as claimed in any one of claims 1117, characterised in that the actuator (31) is under the control of a fiveport pneumatic valve (26).
19. Apparatus as claimed in any one of the preceding claims, characterised in that the valve member (15,16) presents cutting edges circumferentially of the inner surface (23) of the valve body to cut any particulate matter which may extend part way out of a port (12,13,14).
Description:
APPARA TUS FOR METERING FL UIDS FIELD This invention relates to apparatus for metering fluids and in particular, although not exclusively, to apparatus for metering and dispensing liquids or pasty substances which may contain solids or particulate matter. The apparatus of the invention is particularly suitable for the rapid filling of containers with a foodstuff such as yoghurt which contains fruit particles.

BACKGROUND In filling milk into cartons, at high speed, it is the practice to use milk in a hopper which is gravity fed to a volumetric pump through a valve, which allows the defined volume of milk to be fed into a carton. Such high speed machines typically fill one litre cartons, at a rate of one carton per second. Such valves have to open and close quickly. At the same time, the equipment and in particular the valves need to be designed for the possibility of"Clean-In- Place"commonly called"C-I-P valves".

Attempts have been made to convert such machinery for use in filling yoghurt cartons.

However problems are encountered, because yoghurt is more viscous than milk, and yoghurt and some dairy desserts may be provided with fruit pieces (referred to in the trade as"particulates").

These particulates being lumpy can cause valves to jam either in the open or the closed position.

Moreover the viscous nature of yoghurt and other thickened dairy products prevents the product being dispensed accurately simply by gravity, and it is necessary to provide some form of metering pump in order to withdraw a metered quantity of yoghurt from the hopper, and then to supply that metered quantity to the carton. Attempts have been made to solve these problems by using different types of valves, but to date it has not been possible to provide a valve which is fast enough in operation, or which can accommodate the particulates in the yoghurt without jamming.

OBJECT It is an object of this invention to provide an improved valve and/or actuator, or one which will provide the public with a useful choice.

STATEMENTS OF INVENTION In accordance with the present invention there is provided apparatus for metering fluids which may contain particulate matter, the apparatus comprising a valve body having an inner surface of cylindrical section penetrated by at least three circumferentially spaced apart ports, two of which are respectively an inlet and an outlet port, a valve member, means for rotatably moving the valve member within the valve body between first and second positions in which the valve member alternately opens one of said inlet and outlet ports while closing the other said outlet and inlet port and means for producing a pressure difference at the remaining port or ports whereby in use a fluid will be sucked into the valve body through the inlet port and expelled from the valve body through the outlet port, the valve member being selectively moveable in the valve body to a third position in which none of the ports is obturated by the valve member.

In preferred embodiments of the invention said ports are three in number, said remaining port communicating with a pump which alternately applies suction and pressure to the interior of the valve body.

Also in preferred embodiments of the invention the inlet and outlet ports are respectively at the top and bottom of the valve body, a single remaining port penetrating the valve body generally horizontally.

The valve member may be an annulus formed with circumferentially spaced apertures each of which will open a port when aligned therewith, a port being closed when no said aperture is aligned therewith.

Alternatively the valve member may comprise a rotatable shaft from which arms extend radially in angularly spaced relation, each arm bearing at its distal end a shoe the radially outer surface of which is shaped complimentarily to the inner surface of the valve body.

Said arm and shoe assemblies are preferably two in number and adopt on the shaft a position approximately corresponding to the hands of a clock in the 5 o'clock position.

The shoes may be spring loaded on the arms to be urged into contact with the inner surface of the valve body.

The inner surface of the valve body is preferably frusto-conical, the surface (s) of the valve member presented to said inner surface having a complimentary shape, and means is preferably provided whereby the valve member may be displaced axially relative to the valve body thereby to move the valve member out of contact with the inner surface of the valve body.

Means is preferably provided to limit the extension of each shoe from the associated arm when the valve member is moved axially away from the valve body. The said means may comprise an arcuate extension of each shoe into a cylindrical extension of the valve body, said extensions cooperating to limit the radially outward movement of the shoes relative to the arms.

The apparatus preferably further comprises an actuator for imparting oscillating rotational movement to the valve member, the acuator comprising a pinion non-rotatable relative to the valve member and a pair of racks on opposite sides of the pinion, means being provided for oppositely longitudinally displacing the racks to impart oscillating rotary movement to the pinion.

The said means for oppositely displacing the racks may comprise a piston connected to each rack, each piston being displaceable in a cylinder in response to unequal fluid pressures in a cylinder at opposite ends of the piston therein.

The unequal fluid pressures may be produced by pneumatic apparatus which alternately vents the ends of each cylinder while supplying air under pressure to the cylinder at the opposite end of the piston therein.

Means is preferably provided for selectively lengthening the stroke of one of the pistons in the associated cylinder thereby to rotate the valve member to said third position thereof. A larger piston may be moveable in an enlargement of one of said cylinders at one end of the smaller, firstmentioned piston therein, said enlargement being normally supplied with air under pressure

on the side of the larger piston remote from the smaller piston thereby to limit the stroke of the smaller piston, said enlargement being vented when it is desired to move the valve member to said third position thereof thereby to lengthen the stroke of the smaller piston.

Means may be provided for displacing the valve member axially between operative and cleaning positions. In a preferred embodiment said means comprises pistons at opposite ends of the valve member, one of said pistons being moveable in a cylinder within the shaft of the pinion of the actuator.

The actuator may be under the control of a five-port pneumatic valve.

Preferably the valve member presents cutting edges circumferentially of the inner surface of the valve body to cut any particulate matter which may extend part way out of a port into the interior of the valve body.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view of apparatus in accordance with the invention; Figure 2 is an end view of the valve 10 shown in Figure 1 with an end plate removed; Figure 3 is a cross-section taken on the line III-III of Figure 2; Figure 4 is a cross-sectional view through an actuator for the valve of Figures 2 and 3; Figure 5 is a sectional view showing the valve of Figures 2 and 3 joined to the actuator of Figure 4; Figure 6 is a section in a transverse plane of an alternative embodiment of the invention; Figure 7 is a perspective view of the valve member of the valve of Figure 6; Figure 8 is a section in a longitudinal plane through the component shown in Figure 7, and Figure 9 is a view in the direction of the arrow A in Figure 9.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Figure 1 schematically illustrates a hopper 21 capable of containing a dairy product 22 such as yoghurt containing particulates (for example small fruit chunks). This hopper is connected to a rotary valve 10 having three ports, the top port being an inlet port connected to the hopper, the bottom port being an exit port to allow material to be fed into cartons 24, and the side port being connected to a reciprocating pump 25 capable of sucking a metered quantity of material into the valve 10 and then expelling it via the bottom port in order to fill a carton to the required level.

The rotary valve 10 is preferably pneumatically controlled by a five port valve 26, shown schematically in Figure 1, whereas the reciprocating pump 25 is preferably cam operated. The reciprocating pump shown in Figure 1 is part of a conventional machine as is the hopper, whereas the valve 10 is in accordance with the present invention.

The valve 10 and its actuator have been developed to be used as a retrofit with an existing dairy product filling machine which utilises a hopper and a reciprocating pump. Before describing the valve and actuator in detail, it is desirable to give some background of the existing filling machine.

EXISTING MACHINE An existing dairy product-filling machine, specifically designed to volumetrically fill one litre cardboard cartons with milk, is to be modified to allow the machine to cope with liquids incorporating particulates (eg small fruit chunks).

The filling machine cannot accomplish this task at present due to the existing spring loaded type valve system. These valves were designed for liquids only and cannot cope with any solids that may be present in the liquid product since the valves rely only on spring pressure to close them securely on their seatings. Any solids will hold the valves open and render the filling machine inoperable.

A special valve is required to be retro-fitted to this existing filling machine and therefore must fit dimensionally into existing pipework and fittings.

The action of this special valve must be very fast since the pumping action employed by the existing filling machine is directly cam operated so that the interval between pumping in and pumping out is minimal.

Design Reauirements The primary requirement of the main valve is to allow liquid dairy products; such as yoghurt, custard or similar, mixed with fruit particulates (eg small chunks of fruit) to be moved from a hopper above the main valve, through the main valve to a metering pump cylinder chamber, then dispensed into cartons below.

The dairy products may be cold or hot.

The machine cycle time is typically 6500 cartons per hour. Since the filling machine is a two- lane unit, each valve must operate at 3250 cycles per hour.

A second requirement is to allow the main valve, hopper and cylinder chamber to be flushed with CIP (Clean-In-Place liquid) during which all three ports in the main valve must be open.

Due to the above brief, a valve has been designed and also a rotary actuator to accomplish the unusual requirement of three valve positions.

Valve Turning now to Figures 2,3 and 5 the valve 10 has a valve body 11, an inlet port 12, an outlet port 13 at 180° from the inlet port, and a pump port 14 at 270° from the inlet port. A valve member comprises two valve shoes 15,16 arranged as shown in Figures 3 and 4, connected to a rotatable shaft 18 by means of sleeves 19 and springs 20 (best seen in Figure 3) so that the valve shoes are biased radially outwards towards the inner surface 23 of the valve body.

Looking at Figure 2, the lower shoe 16 is not closing the lower port 13 whilst the upper shoe 15 is in a position which closes the upper port 12. Note that the circumferential width of the shoes is slightly greater than the diameter of the ports so that an imprecise rotational movement of the valve member will still allow the shoes to fully close the ports when moved into the"closed position".

This valve 10 is configured so that the normal use will allow the valve shoes 15,16 to open or close the inlet and outlet ports 12,13 speedily, whilst normally allowing the pump port 14 to remain open. Thus the valve 10 will have two main positions, a first position in which the product 22 can flow through the inlet port 12 and out through the pump port 14 into the reciprocating pump 25, and a second position in which the upper inlet port 12 is closed, and the lower outlet port 13 is open allowing product 22 to be pumped from the pump 25 through the pump port 14 and out through the outlet port 13 to a carton 24 situated below the outlet port.

Preferably the rotatable shaft 18 is driven by a pneumatically controlled actuator 31 shown in Figures 4 and 5. The rotatable shaft 18 of the valve 10 has a pinion 30 shown in Figures 4 and 5 thereon capable of meshing with a pair of racks 42,43 of the actuator. However, it will be appreciated that the pump 10 may be used with other types of actuators or controls.

Actuator Looking at the cross-sectional view of Figure 4, the actuator 31 has a pair of first pistons 34,35 capable of reciprocating within a pair of cylindrical bores 36,37. Each bore has a port allowing air to flow in or out of that bore. The first bore 36 has a port 38 and the second bore 37 has a port 39.

Each piston has a cut-away portion 40,41 containing a respective rack 42,43 engaging the pinion 30 of the rotatable shaft 18. Each piston 34,35 is provided with a co-axial smaller piston 53. Bore 36 opens out to a wider bore 50 whilst bore 37 opens out to a correspondingly wider bore 51. Bore 50 contains a secondary piston 52, whereas bore 51 contains, in this instance, a fixed block 56. In either case, the smaller pistons are slidably sealed into the secondary piston 52 and the block 56. A port 54 allows the entry or exit of air from bore 50. The interiors of the secondary piston 52 and the block 56 are fed with air through ports Q and P respectively.

To operate the actuator 31 described above, pressurised air is fed or vented in the following sequence. In normal operation, air is fed through the port 54, causing the secondary piston 52 to be held at its right-hand position, as shown in Figure 4.

moved towards the right in synchronism with the piston 34. This rotates the pinion 30 anti- clockwise.

When pressurised air is fed to ports 39 and Q, ports 38 and P being vented, the piston 35 is moved to the left until it abuts the block 56. The piston 34 moves to the right in synchronism with the piston 35. This rotates the pinion 30 clockwise.

The supply of pressurised air to and venting of the ports 38,39, P and Q is cycled at a controlled rate by operation of the 5-port pneumatic valve 26.

Operation of the Valve Considering Figure 2 the upper valve shoe 15 is shown in its position closing the inlet port 12 while the outlet port 13 is open. If the rotatable shaft 18 of the valve 10 is rotated through 35° clockwise the upper valve shoe 15 will move into the open position, and the lower valve shoe 16 will move clockwise into a position closing the outlet port 13 so that the outlet port is fully closed, and the inlet port 12 is fully opened by the upper shoe 15.

However if the rotatable shaft 18 is allowed to move an additional 35°, i. e. it moves a total of 80° from the position shown in Figure 2, then the lower valve shoe 16 will be situated at the 80° position between the inlet and outlet ports 12,13, whilst the upper valve shoe 15 will be moved to a position between the inlet port 12 and the pump port 14, so that all three ports are now held open allowing for the possibility of clean-in-place, a technique in which a cleaning fluid is passed through the hopper, pump and the valve.

Preferably the valve 10 is formed of hygienic and wear resistant components. Most of the valve body can be formed of stainless steel, or hygienic plastics. In particular the valve shoes 15,16 are conveniently formed of a plastic known as"PETP". It is desirable that the valve body itself is formed of stainless steel so that the plastic valve shoes slide on the interior conical surface of the valve body.

By shaping the valve shoes as shown in Figure 2, with two sharp or knife edges, the valve shoes can be used to chop off any portions of fruit or other particulates that might be otherwise jammed in a valve port as the valve shoe moves into the closed position.

By using two valve shoes situated as shown in Figure 2 it is possible to speed up the opening and closing of the ports.

Filin, Operation During the following operations, compressed air is continuously present at port 54 in the actuator 31. This ensures that the larger piston 52 acts as a stop for the smaller piston 34 in the actuator.

The proprietary five port pneumatic valve 26 is used to control the movements of the actuator as shown in the schematic diagram of Figure 1.

Operations 1. When compressed air from the five port valve 26 is directed to the actuator inlet ports 39 and Q, this operates the rack and pinion in the actuator to revolve the valve shoes 15,16,45° clockwise which blocks off the outlet port 13 and opens the inlet port 12. Air from ports 38 and P is exhausted through the valve 26.

2. The piston of the metering pump 25 retracts to suck in product 22 from the hopper 21 and into the pump 25.

3. The compressed air from the five port valve is then directed to the actuator ports 38 and P.

At the same time, the air from actuator ports 39 and Q is exhausted through the five port valve.

This operates the rack and pinion 30,42,43 in the actuator 31 to revolve the main valve double shoes 15,16,45° anti-clockwise which blocks off the hopper inlet port 12 and opens the outlet port 13.

4. The metering pump piston extends to push the product 22 from the pump 25 through the outlet port 13 and into the carton 24 waiting below.

5. These operations repeat for the duration of the production run.

4. The metering pump piston extends to push the product 22 from the pump 25 through the outlet port 13 and into the carton 24 waiting below.

5. These operations repeat for the duration of the production run.

Cleaninz Operation This operation requires the main valve to have all three of its ports 12,13,14 clear of shoes 15, 16. To achieve this, the shoes 15,16 need to move to a third position such that they do not cover any port.

The air pressure on the port 54 is turned off and the port is vented. This enables the small piston 34 to move the large piston 52 to the left in Figure 5 which in turn allows the piston 34 to travel a further distance.

The shoes 15,16 in the main valve now move an additional 35° anti-clockwise. (One shoe is now positioned between the inlet port and pump port, and the other shoe is positioned opposite the pump port).

This results in both shoes moving to a position such that all three ports in the main valve are open.

At this point the cleaning operation may take place.

While the secondary piston 52 is at the left-hand position, the pistons 34,35 can continue to be oscillated during the cleaning operation.

When the cleaning operation is completed, the compressed air is reconnected to port 54 in the actuator, which moves the large piston 52 back to its first position.

The unit is now ready to resume the filling operations.

The valve body 11 is formed with a surface 23 which is tapered and coaxial with the shaft 18.

The outer surfaces of the shoes 15,16 match the surface 23 of the valve body 11, except for a

short cylindrical land or extension 57 which bears against a cylindrical surface 70 formed in a sideplate of the body 11 as an extension of and coaxial with the surface 23.

During normal operation, the shoes 15,16 bear against the surface 23. For cleaning purposes, the shaft 18 and shoes 15,16 carried thereby are moved to the left in Figure 3, so that the cylindrical land 57 bears against the surface 70 to prevent outward movement of the shoes 15, 16. Thus, the whole surface 23 and the surfaces of the shoes 15,16 presented to it will be washed by the cleaning fluid.

An end cap 67, mounted on the valve body 11 or an end plate thereof, has a pneumatic piston 68 slidable therein and coaxial with the shaft 18. The piston 68 has an extension 69 which protrudes through the centre of the end cap 67. The amount of protrusion of the piston 68 indicates the axial position of the shoes 15,16.

A pressurised air line is connected to a port 71 in the end cap 67, whereby pressurised air can be applied to the piston 68 to urge it and the shaft 18 towards the right in Figure 3 until an annular bearing ring 65 abuts the right hand bearing 81 at 84.

The interior of the pinion 30 is formed as a pneumatic cylinder 75 (Figure 5) in which a piston 76 is slidable, the piston 76 being formed on one end of a pin 77 slidable coaxially in a bore in the pinion 30. The opposite end of the pin 77 bears against a stainless steel ball 78 captive in the right hand end of the shaft 18. An end plate 79 transfers air from an air line 80 into the cylinder 75. When it is required to clean the valve 10, air is vented through the port 71 and pressurised air is fed through the air line 80 thereby pushing the piston 76, the pin 77, the ball 78, the right hand end of the shaft 18 and the shoes 15,16 towards the left. When the cleaning procedure is complete, air is evacuated from the cylinder 75 through the air line 80 and air, at controlled pressure is again admitted through the port 71, so as to move the shoes 15,16 towards the right and into their working position with the valve body 11. A hollow plug 85 is a press fit in the cylinder 75, so that the angular position of the external end face of the plug 85 indicates the angular location of the actuator and of the shoes 15,16.

ADVANTAGES The two shoe valve is able to operate at high speeds and accommodate dairy foods with particulates. The novel actuator allows for two or three (or possibly more) rotational positions of the shaft, and is particularly suited for use with the novel valve. The spring loading 20 of the valve shoes 15,16 allows the pump to cope with a"dead head"condition, if the pump is assembled wrongly (after a service) with one valve shoe closing the pump port 14 on the pump cycle. In that condition pump pressure would push the valve shoe away from the port to allow material to be expelled.

It has been found that the two shoe valve is able to handle hot materials by virtue of the radial movement available to the valves shoes 15,16.

VARIATIONS The preferred valve or actuator may be modified to accommodate other operations. For example the valve itself may be modified to a four port valve, and it would be possible to use two or more shoes depending upon the required speed of operation of such a valve. The actuator could be modified to allow for two, three, four or potentially more rotatable positions by using more than one stop piston and varying the air pressure to the one or more stop pistons to control the movement of the main primary piston.

The attached drawings show one large piston 52 since on this occasion only three different positions are required. A further large piston may be installed in place of the block 56 to provide a fourth position.

Figures 6 to 9 show an alternative design of valve to that shown above. The actuator 31 and rotatable shaft 18 operate in the manner already described. A valve plug 61 has a taper corresponding to the surface 23 and is a close fit thereto. The valve body 11 is provided with an inlet port 12 and outlet port 13 and a pump port 14 substantially as described above. The centre of the plug 61 is formed as a sleeve 62 mounted on and keyed to the left hand half of the shaft 18, whereby the plug 61 can be oscillated angularly about its axis by the actuator 31.

surface of the plug 61 and the mating surface 23 of the valve body 11. Cleaning liquid can then be flushed through all of the ports and passages within the valve 10, which are exposed to the product being metered.

In Figure 7 it will be seen that the valve plug 61 has four openings 72,73,74 and 83. Opening 83 is substantially circular or oval, whereas, to ensure a sharp cut-off, the openings 72,73,74 are rectangular, being circumferentially short and of maximum axial length.

Figure 9 shows the valve plug 61 in the position required for drawing the product from the hopper and into the metering valve. The opening 72 is aligned with the inlet port 12 so that product can pass down from the hopper into the interior of the plug 61. The lower part of the opening 83 is opposite the port 14 so that the pump can draw the product from the plug 61. The lower part of the plug 61 closes off the outlet port 13. The opening 74 is closed off.

When the metering pump is full, the actuator 31 rotates the plug 61 through approximately 45 degrees clockwise from the position shown in Figure 9. The inlet port 12 will then be closed off by the upper part of the plug 61, the upper part of the opening 83 is aligned with the port 14 and the opening 73 is aligned with the outlet port 13, so that the pump can discharge its metered quantity of product out of the valve 10 and into the waiting carton. The opening 74 is closed off.

When it is required to clean the interior of the valve 10 and the pump, in addition to moving the plug 61 towards the left in Figure 6, as described above, the actuator 31 is caused to rotate the plug 61 through approximately 45 degrees anti-clockwise from the position shown in Figure 9.

Thus, the upper part of the opening 83 is aligned with the inlet port 12, the opening 73 is aligned with the pump port 14 and the opening 74 is aligned with the outlet port 14. Thereby, the inlet port 12 outlet port 13 and pump port 14 and the openings 73,74,83 are open simultaneously. with the pump port 14 and the opening 74 is aligned with the outlet port 14. Thereby, the inlet port 12 outlet port 13 and pump port 14 and the openings 73,74,83 are open simultaneously.