FURBY, David (165 Whalans Road, Greystanes, New South Wales 2145, AU)
WILSON, Neil (69-71 Clapham Road, Sefton, New South Wales 2162, AU)
FURBY, David (165 Whalans Road, Greystanes, New South Wales 2145, AU)
Claims
1. An injection or dosing apparatus including at least one first chamber and piston assembly for receiving a first flowable material and at least one second chamber and piston assembly for receiving a second flowable material characterised in that said first and second chambers and piston assemblies are mounted on an actuator or actuators for movement of said pistons into said chambers.
2. An apparatus as claimed in claim 1 wherein said pistons are secured to one or more piston supports.
3. An apparatus as claimed in claim 1 or 2 wherein said chambers are secured to a respective one or more chamber supports.
4. An apparatus as claimed in any one of the preceding claims wherein said one or more chamber supports and piston supports are adapted for movement relative to each other.
5. An apparatus as claimed in any one of the preceding claims wherein movement is effected by means of one ore more screw members.
6. An apparatus as claimed in any one of the preceding claims wherein said movement is effected by means of one or more motor means.
7. An apparatus as claimed in any one of the preceding claims wherein said piston and chamber assemblies are as claimed in any one of claims 25 to 27.
8. An apparatus as claimed in any one of the preceding claims wherein outputs of said first and second chamber and piston assemblies are fed to a mixing device.
9. An apparatus as claimed in claim 8 wherein said mixing device is a shear mixer or a transfer mixer or rotary mixer or any other appropriate mixer.
10. An apparatus as claimed in any one of claims 8 or 9, wherein said mixing device operates by means of rotary motion.
11. An apparatus as claimed in any one of claims 6 to 10, wherein said drive of said mixing device is provided by means of a motor means.
12. An apparatus as claimed in claim 11 when appended to claim 6, wherein said motor means to drive said piston and chamber assemblies and said mixing device is a single motor means.
13. An apparatus as claimed in claim 8 where a rotation of said motor means simultaneously evacuates said chambers and rotates said mixer.
14. An apparatus as claimed in claim 13 wherein said mixer rotates only when said motor . means rotates so as to evacuate said chambers.
15. An apparatus as claimed in any one of the preceding claims wherein one or more further materials to be added to said and first second materials are added at the entry to said mixer.
16. An apparatus as a claimed in any one of the preceding claims, wherein output from said apparatus is fed to an injection system and then forced under pressure into a mould.
17. An apparatus as claimed in any one of the preceding claims wherein output from said apparatus is forced directly into a mould under pressure provided by said chamber and piston assemblies.
18. An apparatus as claimed in claim 14 wherein between an output shaft from said motor means and an input shaft of said mixer there is at least one one-way clutch device to permit said output shaft to drive said input shaft in one direction only.
19. An apparatus as claimed in any one of the preceding claims wherein said screw means is a ball screw means which is rotated by a motor means.
20. An apparatus as claimed in claim 19, wherein a ball nut is mounted on said chamber support to be driven by said ball screw when said ball screw is rotated by said motor means.
21. An apparatus as claimed in any one of the preceding claims wherein said chamber support is moveable and is located between two stationary supports.
22. An apparatus as claimed in claim 22 wherein one of said stationary supports is said piston support.
23. An apparatus as claimed in any one of the preceding claims wherein said at least one piston support is moveable and is located between two stationary supports.
24. An apparatus as claimed in claim 22 wherein one of said stationary supports is said at least one chamber support.
25. An apparatus as claimed in any one of claims 21 to 24 wherein one of said stationary supports rotatably mounts one end of said screw means. U
26. An apparatus as claimed in any one of the preceding claims wherein said piston's internal diameter together with the speed of said piston moving relative to said chamber controls a flow rate of material from said chambers.
27. A piston and chamber assembly characterised by said piston having an outlet passage therethrough so that as said piston moves into said chamber a liquid or viscous material in said chamber will evacuate said chamber.
28. A piston and chamber assembly as claimed in claim 25 wherein said chamber and said piston include a one-way valve on the chamber inlet and piston outlet.
29. A piston and chamber assembly as claimed in claim 25 or 26, characterised in that said piston provides substantial, or substantially complete, evacuation of said chamber once said piston has fully entered said chamber.
30. An apparatus as claimed in any one of the preceding claims, wherein a third or more subsequent materials is or are added to the first and second materials.
31. An apparatus as claimed in claim 28 when dependent on claim 8, wherein the third or more subsequent material is added at an entry to the mixing device.
32. An apparatus as claimed in claims 28 or 29 wherein movement of said third or more • subsequent components) is controlled separately or independently from movements of said first and or said second materials.
33. An apparatus as claimed in claim 30, wherein said movement of said third or more subsequent components) is controlled by a motor means.
34. An apparatus as claimed in any one of the preceding claims wherein said motor means is one of, or in the case of multiple motor means one or more than one of the following: a servo drive; and electric motor, an AC motor; a 6 speed AC motor; a pneumatic motor; an hydraulic motor.
35. An apparatus as claimed in any one of the preceding claims, wherein said first and second piston and chamber assemblies are moved simultaneously to dispense their contents.
36. An apparatus as claimed in any one of claims 1 to 35, wherein said first and second piston and chamber assemblies are moved independently to dispense their contents.
37. An apparatus as claimed in any one of the preceding claims, wherein if there is three or more piston and chamber assemblies, the assemblies are arranged so that they operate as • follows: all operate independently of each other; all operate simultaneously with each other; at least two operate simultaneously with each other, while the rest operate independently of the at least two which operate simultaneously; at least two operate simultaneously with each other and the rest operate simultaneously with each other but independently with respect to the two which are operating simultaneously.
38. A canister or container evacuation apparatus including means to hold an open canister so as to have its contents evacuated therefrom, said apparatus including a diaphragm with an outlet therein and a tube connected thereto, said diaphragm being able to be inflated on one side to force said diaphragm into the contents of said canister thereby forcing said contents through said outlet and said tube.
39. A canister or container evacuation apparatus as claimed in claim 38, wherein in use, said canister is in an upside down condition.
40. A canister or container evacuation apparatus as claimed in claim 38 or 39, wherein said diaphragm can expand to substantially line inner surfaces of said canister for the purposes of substantial, or substantially complete, evacuation of said canister.
41. A canister or container evacuation apparatus as claimed in any one of claims 38 to 40, wherein there is also included reinforcement means to reinforce the wall or walls of said canister.
42. A canister or container evacuation apparatus as claimed in claim 41 , wherein said means to hold an open canister includes said reinforcement means.
43. A canister or container evacuation apparatus as claimed in claim 42, wherein said reinforcement means includes a cylindrical or part conical formation.
44. A canister or container evacuation apparatus as claimed in claim 41, wherein said reinforcement means is independent of said canister.
45. A canister or container evacuation apparatus as claimed in claim 44, wherein said reinforcement means engages said canister prior to said canister being assembled into said apparatus.
46. A canister or container evacuation apparatus as claimed in claim 45, wherein said reinforcement means is a band or a tubular sleeve which engages the outside wall of said ' canister.
47. A canister or container evacuation apparatus as claimed in any one of claims 41 to 46, wherein said reinforcement means is selected from one or more or the following: a polymeric material; Kevlar; a composite material; a web or webbing; other generally inextensible material.
48. A canister or container evacuation apparatus as claimed in any one of claims 38 to 47, wherein said tube includes, at its end or at another location on said tube, a releasable securement fitting, which enables said apparatus to be readily removed from an injection moulding machine.
49. A canister or container evacuation apparatus as claimed in claim 48, wherein said a releasable securement fitting is selected from one of the following: a bayonet fitting; a plug-in fitting; a quick release fitting.
50. A canister or container evacuation apparatus as claimed in any one of claims 38 to 49, wherein said apparatus includes means to prime both sides of said membrane, said means can include valves or such like.
51. A canister or container evacuation apparatus as claimed in any one of claims 38 to 50, wherein said diaphragm is formed from one or more membranes.
52. A canister or container evacuation apparatus as claimed in any one of claims 38 to 51, wherein said apparatus includes a gear pump to increase the rate of evacuation of said contents. |
Improved Injection and or Dosing System
Field of the invention
[001] The present invention relates to injection apparatus and dosing apparatus for use with injection moulding systems. The invention also relates to a canister evacuation system.
Background of the invention
[002] The injection moulding of silicone rubber products is a complex art and the use of dosing systems is an important aspect of such injection moulding and is used to satisfactorily combine a number of materials so as to form the silicone rubber compound including foamed silicone rubber compound.
[003] Any reference herein to known prior art does not, unless the contrary indication appears, constitute an admission that such prior art is commonly known by those skilled in the art to which the invention relates, at the priority date of this application.
Summary of the invention
[004] The present invention provides an injection or dosing apparatus including at least one first chamber and piston assembly for receiving a first flowable material and at least one second chamber and piston assembly for receiving a second flowable material characterised in that the first and second chambers and piston assemblies are mounted on an actuator or actuators for movement of the pistons into the chambers.
[005] The pistons can be secured to one or more piston supports.
[006] The chambers can be secured to one or more chamber supports.
[007] The chamber supports and piston supports can be adapted for movement relative to each other.
[008] The movement can be effected by means of one or more screw members.
[009] The movement can be effected by means of one or more controllable motor means.
[010] The piston and chamber assemblies can be as described below in paragraphs
[028] to [030] below.
[011] The output of the first and second chamber and piston assemblies can be fed to a mixing device.
[012] The mixing device can be a shear mixer, a transfer mixer, or other rotary or appropriate mixer.
[013] The mixing device can operate by means of rotary motion.
[014] The rotary drive of the mixing device can be provided by means of a motor means.
[015] The motor means described in paragraphs [009] and [014] can be the same motor means.
[016] The rotation of the motor means can simultaneously evacuate the chambers and rotates the mixing device.
[017] The mixing device can be made to rotate only when the motor means rotates so as to evacuate the chambers.
[018] A third or subsequent material can be added to the first and second materials, the third or subsequent material can added at the entry to the mixer.
[019] The output from the mixer can be fed to an injection system and then forced under pressure into a mould.
[020] The output from the mixer can forced directly into a mould under pressure provided by the chamber and piston assemblies.
[021] Between an output shaft from the motor means and an input shaft of the mixer there can be at least one one-way clutch device to permit the output shaft to drive the input shaft in one direction only.
[022] The screw means can be a ball screw means which is rotated by a motor means.
[023] A ball nut can be mounted on the chamber support to be driven by the ball screw when the ball screw is rotated by the motor means.
[024] The at least one chamber support can be movable and can be located between two stationary supports.
[025] One of the stationary supports can be the at least one piston support.
[026] The at least one piston support can be moveable and be located between two stationary supports.
[027] One of the stationary supports can be the at least one chamber support.
[028] One of the stationary supports can rotatably mount one end of the screw means.
[029] The piston's internal diameter together with the speed of the piston moving relative to the chamber controls the flow rate of the material from the chambers.
[030] The present invention also provides a piston and chamber assembly characterised by the piston having an outlet passage therethrough so that as the piston moves into the chamber a liquid or viscous material in the chamber will evacuate the chamber.
[031] The chamber and the piston can include a one-way valve on the chamber inlet and piston outlet respectively.
[032] The piston can provide substantial, or substantially complete, evacuation of the chamber once the piston has fully entered the chamber.
[033] A third or more subsequent material can be added to the first and second materials.
[034] The third or subsequent material can be added at an entry to the mixing device.
[035] A movement of the third or more subsequent component can be controlled separately or independently from movements of the first and second materials.
[036] The movement of the third more or subsequent component can be controlled by a motor means.
[037] In the preceding description, the motor means can be one of, or in the case of multiple motor means multiples ones of or more than one of the following: a servo drive; and electric motor; an AC motor; a 6 speed AC motor; a pneumatic motor; or a hydraulic motor.
[038] The previously described apparatus can be such that the at least one first and second piston and chamber assemblies can be moved simultaneously to dispense their contents; or alternatively can be moved independently to dispense their contents.
[039] If there are three or more piston and chamber assemblies, the assemblies are arranged so that the movement of the pistons into the chambers of these assemblies is as follows: all move independently of each other; all move simultaneously with each other; at least two
move simultaneously with each other, while the rest move independently of the at least two which move simultaneously; at least two operate simultaneously with each other and the rest operate simultaneously with each other but independently with respect to the two which are operating simultaneously.
[040] The present invention further provides a canister or container evacuation apparatus including means to hold an open canister so as to have its contents evacuated therefrom, the apparatus including a diaphragm with an outlet therein and a tube connected thereto the diaphragm being able to be inflated on one side to force the diaphragm into the contents of the canister thereby forcing the contents through the outlet and the tube.
[041] In use, the canister or container can be in an upside down condition.
[042] The diaphragm can expand to substantially line inner surfaces of the canister for the purposes of substantial, or substantially complete, evacuation of the canister.
[043] The canister or container evacuation apparatus can also include reinforcement means to reinforce the wall or walls of the canister.
[044] The means to hold an open canister includes the reinforcement means.
[045] The reinforcement means can include a cylindrical or part conical formation.
[046] The reinforcement means can be independent of the apparatus.
[047] The reinforcement means can engages the canister prior to the canister being assembled into the apparatus.
[048] The reinforcement means can be a band or a tubular sleeve which engages the outside wall of the canister.
[049] The reinforcement means can be selected from one or more or the following: a polymeric material; Kevlar; a composite material; a web or webbing; another generally inelastic material.
[050] The tube can include, at its end or at another location on the tube, a releasable securement fitting, which enables the apparatus to be readily removed from an injection moulding machine.
[051] The releasable securement fitting can be selected form one of the following: a bayonet fitting; a plug-in fitting; a quick release fitting.
[052] The apparatus can include means to prime both sides of the membrane, the means can include valves or such like.
[053] The diaphragm can be formed from one or more membranes.
[054] The canister or container evacuation apparatus can include a gear pump to increase the rate of evacuation of the contents.
Brief description of the drawings
[055] An embodiment or embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
[056] Figure 1 illustrates a cross section through injections and dosing system which is also connected to a mixer;
[057] Figure 2 illustrates the chamber and piston assembly detail;
[058] Figure 3 illustrates a third part additive injection system;
[059] Figure 4 illustrates an arrangement showing where third part additives enter the shear mixer;
[060] Figure 5 illustrates a cross section through a truncated conical pail or canister evacuation apparatus;
[061 ] Figure 6 illustrates the apparatus of Figure 5 with partial expansion;
[062] Figure 7 illustrates the apparatus of Figure 5 with full expansion;
[063] Figure 8 illustrates a cross section of the diaphragm used with the apparatus of
Figure 5 through lines Vl 11 - Vl 11 of Figure 9;
[064] Figure 9 illustrates a plan view of the diaphragm used with the apparatus of
Figure 5;
[065] Figures 10 to 13 illustrate the stages of deployment of an improved apparatus similar to that of Figures 5 to 9.
Detailed description of the embodiment or embodiments
[066] Illustrated in Figures 1 and 2, is an injection and dosing system 10 comprising piston and chamber assemblies 12, a rotary shear mixer 14 and a servo drive or motor 16 to drive the system 10.
[067] The piston and chamber assemblies 12 have a central drive shaft 30 which is rotatably mounted via a bearing 39 into a stationary bearing support 26. The bearing support 26 has an overall dimension generally the same as that of the chamber support 36 and that of the piston support 28. The supports 28, 36 and 26 are preferably of a tri-lobal configuration or arrangement, being generally triangular in shape and have three support rods 33 (the third being not visible because section views are provided). The rods 33 are secured via their respective ends by means of plates 35 and Allen screws 37 to prevent any outboard movement of the supports 28 and 26 relative to the rods 33. The rods 33 also include shoulders to abut the inboard faces of Hie supports 28 and 26 so as to prevent the supports 28 and 26 from moving towards each other.
[068] The shaft 30, as illustrated in Figure 1, includes a toothed drive pulley 20 which is connected to a toothed drive pulley 18 by means of a steel reinforced toothed belt 22, and an idler/tensioner pulley 24. By this arrangement the rotation of the servo drive or motor \6 will cause rotation of the shaft 30.
[069] The end 31 of the drive shaft 30 is connected to a one way clutch 56 which engages the inner circumference of a hollow drive wheel 57 which is in turn connected to the input drive shaft 64 of a rotary shear mixer 14. This will be described in more detail later.
[070] Between the ends of the drive shaft 30 is a ball screw 32. The ball screw 32 is engaged by a ball nut 34 which is securely mounted to the chamber support 36. The chamber support 36 like the other supports 26 and 28 is tri-lobal however there are three cylindrical apertures in the support 36 which receive slide bearings and seals 38, so that the support 36 can slide in either direction along the rods 33 when the ball screw 32 is rotated relative to the ball nut 34.
[071] The chamber support 36 has inlets 47 and 49 (shown in Figure 2) to allow connection to a supply of liquid or viscous A and B components to form a silicone based injectable material, which when mixed and then subjected to heat, will set to form a moulded silicone rubber compound. The inlets 47 and 49 provide passages which will lead to the base of chambers 42 in cylinders 43.
[072] In the base of the chambers 42 are respective one way inlet valves 46 while in the outlet of the piston 44 are located one way valves 48.
[073] The cylinders 43 and chamber support 36 will slide relative to the rods 33 so as to produce relative movement between the pistons 44, which are mounted to the piston support 28, and cylinders 43. It can be seen that the piston 44 has at its chamber end an O-ring seal to the inner circumference of the chamber 42 while the secured end of the piston 44 also has a stationary o-ring seal with the piston support 28. The secured end of the cylinder 43 also has appropriate seals with the chamber support 36 so that leakage does not occur under the pressures produced in the dosing and injection system 10.
[074] Illustrated in Figure 1, inlets 50 and 52 to shear mixer 14 receive product from the respective pistons 44 to feed same into the rotary shear mixer 14. The shear mixer 14 is enclosed in an outer jacket 63 having a cold water inlet 60 and a cold water outlet 61 which allows water to move into and out of a water jacket 63 to keep the contents of the shear mixer 14 cool. Shear mixers can tend to generate heat due to the shear forces generated for the mixing process, as well as the presence of pressure which tends to increase temperature. Thus to prevent the combined mixture of A and B parts from setting from such generated heat, maintaining a cool outer jacket 63 will help to prevent any setting occurring in the mixed compound.
[075] The shear mixer 14 has an outlet 62, and in one embodiment the outlet 62 can go directly to heated mould for injection moulding, with injection occurring under the pressure developed by the piston and chamber assemblies 12. Alternatively the outlet 62 can be connected to the inlet of an injection moulding system whereby the material will now be injected under pressure from the injection moulding system into a mould.
[076] A third component inlet (see Figure 4) similar to the inlets 50 and 52 is provided to allow a third component to be injected into the shear mixer 14 so as to produce a homogeneous mixture of three components at the outlet 62.
[077] The one way clutch 56 (or a multiple of clutches) ensures that as the chamber support 36 moves towards the piston support 28, thereby forcing the piston 44 into the chamber 42 to evacuate its contents, the A and B component passing out of the pistons 44 and into inlets 50 and 52 will be mixed by the shear mixer 14 when the chamber support 36 is moving towards the piston support 28. The one way clutch 56 prevents rotation of the shear mixer 14 when the shaft 30 is being rotated in the opposite direction.
[078] The structure and arrangement of the chamber 42 and piston 44, as can be seen from Figure 2, is such that when the piston 44 travels its maximum distance into the chamber 42, no liquid or viscous material in the chamber 42 will remain. As the piston 44 begins to withdraw
from the chamber 42, one way valve 46 will allow the respective chambers 42 to refill with component A and B under pressure from their supply source attached to the inlets 47 and 49. The pressure of the supply source and the creation of a negative pressure by the piston 44 withdrawing from the chamber 42 cause the chamber 42 to fill up completely with a new shot of components A and B 5 ready for the chamber support 36 to be moved towards the piston support 28 when the shaft 30 is rotated in the opposite driving direction via the servo motor or drive 16.
[079] In the situation where a third component or third part additive is required, a separate system can be utilised to feed into the mixer 14. However as the chamber and piston assemblies 12 are based on a tri-lobal support system, a third cylinder 43, chamber 42 and piston 44 can be included and fed via a third inlet (similar to the inlet 50 or 52) into the mixer 14.
[080] Where two or more piston and chamber assemblies are arranged in the system, the desired proportions of the first, second, third or more parts is controlled by providing pistons and chamber internal diameters which will be of the correct volume ratio to eject into the mixer or a mould the desired proportions.
[081] In order to build a system which has independent control of the third component
(component C), a system such as that illustrated in Figure 3 can be provided, whereby the third component is contained within a canister or container 104 which is secured by bolts 102 on which a plunger 110 is provided so that the third part additive or component underneath the plunger 110 can be pressurized. The third component system 100 of Figure 3 has a piston 138 at the end of a ball screw shaft 128. The piston 138 moves inside the chamber or cylinder 120. The outlet of the canister 104 feeds into a valve block 114 having a one way valve 116 and a second one way valve 118 on the outlet from the system 100 which will feed to the inlet of the shear mixer 14 (see Figure 4). As the plunger 110 applies pressure to the contents of the canister 104 as the piston 138 is retracted from the cylinder 120, liquid flows past the one way valve 116 and fills the cylinder 120. Rotating the servo motor 122 in the opposite direction causes the pulley 124 to also rotate in the opposite direction. As the pulley 124 is connected by a toothed belt drive (not illustrated) to the pulley 126, this will rotate the ball shaft 128 in the opposite direction causing the piston 138 to push the contents out through the one way valve 118 and forcing the one way valve 116 to seal even more tightly.
[082] By providing the components into the shear mixer by means of screw threads the injection and dosing system 10 prevents shock loads, and thus prevents differential mixing that
would otherwise occur. Further, as the dosing systems are injecting under a constant velocity, this prevents acceleration and thus also helps to prevent shock loads.
[083] The shaft 128 has to be prevented from rotating so as to enable the shaft 128 to translate with respect to the pulley 126. Thus the distal end of the shaft 128 is secured in a shaft block 130 which slides within side rails 132 and 134. The shaft 128 is thus prevented from rotation but is permitted to translate.
[084] The amount of pressure under which the component A, component B or component C might be supplied to the inlets 47, 49 and 116 respectively, is such that there needs only be enough pressure so as to create a flow in these locations. These pressures can be increased if desired or needed depending upon the components utilised, in order to limit gasification of the components when the pistons 44 or 138 are withdrawn from their respective chambers.
[085] Whilst the above description only has two piston and chamber assemblies 12 and whilst three or more are readily situated on the tri-lobal supports 26, 28 and 36, anywhere up 4 to 8, or more, different piston and chamber assemblies can be mounted on the supports 36 and 28. The limiting factors are the sizes of these units and the power available to drive the chamber support 36, but this is readily understood by a person skilled in this art.
[086] However in these multi part systems mounted on support blocks 28 and 36, the ratios of the components will be controlled by the relative sizes of the chambers 42 and the outside and inside diameter of the pistons 44. As the stroke to evacuate, i.e., the distance of travel of the pistons 44 into the chambers 42 is known, the sizes of the bores of the chamber 42 and through the piston 44 can be selected together with the outside diameter of the piston 44, so as to produce the correct proportion of components to be mixed into the shear mixer 44. While this is advantageous where large batches of the same percentages of components are made, the use of an independent second or third or fourth (or more) component systems such as that in Figure 3 allows for an injection system to have flexibility in the proportions of parts A, B and other components to be mixed therewith.
[087] As can be seen from Figure 4, the third part or component additive is introduced into the shear mixer 14 at diametrically opposed locations which are radially or circumferentially spaced from the inlets 50 and 52 of Figure 1.
[088] Illustrated in Figures 5 to 9 is a canister or container evacuation system which is suitable for use with 500ml, 1 litre, 2 litre, and other size pails which tend to be tapered or part conical in shape. It can also be used with straight sided pails of 20 litres or more.
[089] In Figure 5, a pail 200 is situated within a pail holder 202 which is capable of withstanding the pressures which may be produced in this system. On top of the pail 200 and sealed with respect to the vessel 202 is a membrane 204 which has a smooth sided outlet pipe 206 connected to a central aperture on the membrane 204. The air cavity 208, when the system is first assembled, can be decreased by applying a vacuum or negative pressure to the outlet 206. Once the air cavity has been removed, regulated air pressure can enter the dry side of the membrane 204 via air inlet 210. Continued application of pressure via inlet 210 will force the membrane 204 to stretch, to firstly unfold the gathered folds and then to stretch as the membrane passes through stage 2 of Figure 6 and stage 3 of Figure 7, wherein complete evacuation of the container 200 by flowable material 2001 exiting occurs and the membrane effectively lines all the internal surfaces of the pail 200. The amount of stretching applied to the membrane ' 204 is desirably within the elastic limit of the material used to manufacture the membrane 204.
[090] Where the containers or canisters used are large or heavy, the system of Figure 5 can be used in the orientation of Figures 5 to 7 where evacuation results in upward movement of the contents. However, as will be described in relation to Figures 10 to 13, if the canisters are of a size allowing them to be inverted, the system can be oriented to evacuate in a downward direction. This allows the weight of the container to assist evacuation, by applying a pressure. This assistance does not occur in the orientation used in Figures 5 to 7.
[091] Illustrated in Figure 8 is a cross section of the membrane in its ungathered format whilst illustrated in Figure 9 is a plan view of the membrane of Figure 8 showing the line of cross section provided in Figure 8. This system can be scaled up for any size pail and ensures that the very expensive part A, B or other part additives are fully evacuated without the need for human contact or intervention during the evacuation process.
[092] In Figures 5 to 8 the evacuation apparatus can include a gear pump to assist with the rate of evacuation of the contents of the canister or container 104. Such a gear pump can be connected to the outlet 206 from the container 104, so as to provide a negative pressure on the outlet passage to increase the speed of evacuation, without having to increase the speed of expansion or stretching of the diaphragm membrane 204.
[093] Figures 10 to 13 illustrate a series of cross sectional views through another canister evacuation apparatus 700 similar to that of Figures 5 to 9. Instead of a supporting wall 202 as in Figure 5 to help resist the internal pressure exerted on the pail or canister 200, a reinforcing sleeve of Kevlar material 750 is first placed around the canister 200 before it is assembled into the evacuation apparatus 700. Once this is done, the canister and Kevlar sleeve 750 are assembled by means of a backing plate 710 and long bolts 711, secured with nuts 712 to the membrane mounting plate 713. The membrane mounting plate 713 includes a membrane securing ring 714, which secures the membrane 715 into position, and clamps its rim to resist the pressures applied for evacuating the canister 200.
[094] The plate 713 and the securing ring 714 include ported passageways and valves or fittings 716 and 717, which allow the evacuation apparatus 700 to be primed, by removing unwanted air from the system, before the evacuation process begins.
[095] An evacuation tube 726 is sealingly connected to the diaphragm or membrane 715 and passes therethrough so as to open on the contents side of the membrane 715. The end of the tube 726 includes a sealable fitting 727 which fits into a bayonet type fitting 728, which is at the inlet end of a content delivery system, such as for the injection moulding system described above. Preferably fitting 728 is located on the outside of a machine covering or guard 729, so that the canisters 200 can be replaced without the need of operators gaining access to the injection moulding machine parts. Appropriate sealing is provided between the fitting 727 and 728, and a lock or bayonet means.
[096] Once the fittings 727 and 728 are locked together, by applying air to the fitting
716 the diaphragm 715 will expand to dispense the contents form the canister 200. As the canister does this the canister will move along the tube 726 until all the contents are evacuated, as is shown in subsequent Figures 11 to 13.
[097] While a Kevlar sleeve 750 is preferred this can be replaced by a series of bands, of any appropriate material. Appropriate materials will be those which are relatively inelastic and of sufficient strength to resist the forces or pressure developed inside the canister during the evacuation process. Bands such as partly conical steel bands which match the taper of the canister 200 could also be used. Other materials such as web or webbing material can be used.
[098] The flexible diaphragm 715 can comprise multiple layers of membranes. This can provide a safety factor, which may be important where the contents of the canister 200 are relatively expensive. Should a first membrane (the membrane that is immediately adjacent to the
product or contents) be stretched beyond its elastic limit and burst, the remaining membrane or membranes keep the product from leaking into the air side of the diaphragm. The more membranes there are in the flexible diaphragm, the less likely the product will leak into the air side, but the stiffer the diaphragm 90 will be. Therefore the appropriate number of membranes in the diaphragm will depend on a balance of these two factors.
[099] While the above description refers to a shear mixer, other types of mixers can be used. For example a transfer mixer or rotary mixer or any other type of appropriate mixer can be used.
[0100] While the above described preferred embodiment has two chamber and piston assemblies 12 for part A and B components, these are moved simultaneously to provide the components to the mixer, by being mounted on the same chamber and piston supports. However, if desired, a single such assembly 12 (or both assemblies 12), can have say the Part A component and the part B component can be provided from a chamber and piston assembly which operate independently to the Part A component. This can be helpful in the case where the part A component has a different viscosity to that of the part B component and thus requires the a different flow rate.
[0101] If there are three or more piston and chamber assemblies, the assemblies can be arranged so that the movement of the pistons into the chambers of these assemblies is as follows: all move independently of each other; all move simultaneously with each other; at least two move simultaneously with each other, while the rest move independently of the at least two which move simultaneously; at least two operate simultaneously with each other and the rest operate simultaneously with each other but independently with respect to the two which are operating simultaneously. This simultaneous movement is achieved by mounting the respective piston and chamber assemblies onto the same chamber supports and piston supports respectively which will provide the pistons and chambers with the same translation distance with respect to each other and the respective dispensing of components is controlled by the respective bore and chamber sizes, whereas the independently moveable piston and chamber assemblers will be mounted on independent supports so as to be independently actuatable or operable.
[0102] The independently operable piston and chamber assemblies can have their movement controlled by a microprocessor or other control means to dispense the injection moulding components in the desired proportions and or according to their viscosity requirements
[0103] The above description refers to servo motors being most preferred which is because of their ability to be accurately controlled by means of microprocessors and control systems, however other motor means can be used to achieve the control, rotation and power requirements of the injection/dosing system. Other motors means can include electric motors, 6 speed AC motors, hydraulic motors or pneumatic motors.
[0104] Where ever it is used, the word "comprising" is to be understood in its "open" sense, that is, in the sense of "including", and thus not limited to its "closed" sense, that is the sense of "consisting only of. A corresponding meaning is to be attributed to the corresponding words "comprise", "comprised" and "comprises" where they appear.
[0105] It will be understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text. All of these different combinations constitute various alternative aspects of the invention.
[0106] While particular embodiments of this invention have been described, it will be evident to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. The present embodiments and examples are therefore to be considered in all respects as illustrative and not restrictive, and all modifications which would be obvious to those skilled in the art are therefore intended to be embraced therein.
Next Patent: WO/2009/152588