| CLAIMS 1) Connection/disconnection device connected between the flow from an extruder and the entrance of a mould injection system that is to be used in a plastic mould injecting machine. This said device has an entrance duct that is connected to the extruder and an exit duct which is connected to the injection system. Both of these ducts have an opening that can be seal coupled between themselves, which allows the connection and communication between each duct and seal. There are recovery tools in place, in case there are any alignment problems when the ducts are opened, and a system to open/close the melt flow channel, which are effectively the two ducts when coupled. 2) The device described in point 1 of these claims, is defined by the fact that the recovery tools in place for misalignment is made from a pipe which has the mentioned entrance and/or exit ducts, with the coupled openings. This pipe tract is axially coupled in a radial way with the corresponding entrance or exit duct in an interposing position, with a flexible neck seal which allows light movement between the said neck and the portion of the pipe which is bound and tightened in the coupling area. 3) This device as mentioned in the claims 1 and 2, is characterizes by the fact that the coupling between the opening of these ducts is vertical, or even more so, the axis of these openings correspond with the direction of the melt flow, which is ver- tical. 4) The device as per claim 3 is characterized by the fact that the said tube is bound to the exit duct. 5) As by one or more of these claims, the device is defined by the fact that these opening/closing devices contain a shutter with at least two moving parts connected to the opening and closing ducts. This shutter is positioned to close the channel between the two ducts, and then it is positioned to open the channel. These two parts are separate and are intended to close the openings of the ducts when they are not coupled. |
DESCRIPTION
Technical Field
This invention is based in the plastic mould injection sector and more specifically it is focused on the connection/disconnection device between the extruder and the injection system in a mould injecting machine.
Aim and Summary of the invention
The invention is based on a Connection/disconnection device between the extruder and the injection system in a mould injecting machine is related to a mould that can be used through the mould injecting of plastic materials. This device in- eludes an entrance duct that is connected to the extruder, and an exit duct, which in turn is connected to the injection system. Both of these ducts have openings that may be coupled and held together in order to connect or communicate between each other. There are recovery tools present in case of misalignment of the coupling during the opening process, and opening/closing tools between the melt flow, which are de- fined by these ducts when coupled.
Notably in this connection/disconnection device, the said recovery tools (in case of misalignment) contain a tube as part of the said entrance/exit ducts, where we find the said coupling opening. This said tube, is also matched with an axial and radial connection which corresponds with the entrance/exit ducts, with the position- ing of a flexible neck seal which allows light movement between the duct where the neck seal is fixed to, and the part where they are hydraulically matched; this tube should attached to the exit end of the duct.
It would be better if the coupling of the entrance ducts of the connection/disconnection device be vertical, or better still, the axel of the entrance duct which corresponds with the flow of the molten flow, be positioned vertically.
It would be better if the entrance/exit lines of the said connection/disconnection device contained an independent moveable shutter valve, made in two parts that could be connected to the said entrance/exit ducts. This shutter valve should have a closing position at the said ducts, and an opening position at the other end of the channel and as two separate parts should be to close the opening of the said ducts when the ducts are not matched.
A detailed description of the embodiment of the invention
The following is a general description of the plant and a detailed description of the invention of the injection system attached to molding system, and the connection / disconnection device between the extruder from the injection system.
- Moulding machine, see table II.
The invention of this moulding machine is detailed in table 11.
This system is an evolution in the field of the injection molding of heterogeneous post-consumer plastics, which improves the process ability, the reduction of cycle times to 42 seconds/ each circa, it doubles the load of injecting using a twin-mould system in a central hot runner. It can also the produce different prod- ucts by using different mould because the hot runners are inserted into their respective molds, this way different weights and geometry perspectives are made possible.
There is a carrousel-rotating system (with each mould connected to the injection system, which can proceed all at the same time. Nb. This part will be defined later), with the possibility of connecting between four to eight moulds (the moulds should be of Quin standard and the injection system should be connected to them). All should be anchored to a central hub carried by a washer and a circular rail support under the molds, so that they can turn at different speeds on a twin motor applied to an outer ring.
It should be noted that the arms on the carousel not only rotate, but each one also allows the radial movement of the moulds themselves, from a rotating position to their injection under the press. See also table 12.
This in turn allows us to control a medium diameter of 6000mm circa; therefore any sluggish movement will also be contained.
This also allows to electricity, hydraulics, traditional and safe water lines to connect through two external refrigerators.
- Requirements and technological specifics that characterize these patented systems and its distinctive elements, which permit significant productive performance and quality. The products that can be molded in this type of machine are volumetric in height, with maximum measurements of 1200x1200. Articles such as pallets used to transport goods.
In order to enhance the quality and quantity of his type of product, twin alumi- num moulds are used (see also how these moulds are used with this injection system in tables Gl, G2, and G3, paying close attention to G2 Fig.), through one hot runner system (Tables G2 Fig., D, E) and 2 homogenization systems. A maximum of 340 pieces/hour may be produced, each weighing 18 kg.
This injection mould system is currently being patented separately: where 42 injections inject into two separate pieces, at a combined weight of 36kg, therefore producing 170 pieces per hr.
The moulds used in creating the final product, are designed to include the crossbars, therefore creating a single piece pallet including any reinforcements for better flexibility, this way we can avoid ulterior unnecessary assembly.
These moulds are set against one another so that the injection starts from the inferior part of the pallet, as seen in table 15 section A-A. This way any unwanted nicks or prints caused by the nozzles are hidden. The quality levels are superior because there are no unevenness or color variations on the platform itself.
Close attention should also be paid to the construction of the hot runner system (see table Gl ref. 1 and 2 of the "injection system") and the internal flow paths which feed the traditional valve nozzles, (Table Gl section A-A).
As you can see, it consists of two semi hollow cavities of stainless steel, which decreases the losses in accordance with their capacities, and is determined by flow simulations. They are severely polished and chrome-lined internally, then welded ex- ternally and bolted internally. This system creates a perfectly polished flow, reducing sluggishness in the product, and obviously creating less energy loss levels than in previous versions.
Another important factor is the balance of the central power unit, where the molten material (using a 2 way system) enters the hot runner system in an equal flowing manner. Therefore, the collector is divided into the hot runner system and the flow of the melt splits (Table Gl section BB of the "injection system "), thus creating a balanced flow.
Hot runner systems that are susceptible to thermal expansion, are free to dilate, as long as long as the anchoring of the mould is developed using slides along the longer axis (Table Gl Ref.10 of the "injection system") which leaves form the central fixed position. Along the smaller axis, dilation is free in the internal part of the same guided system, positioned on the axis which injects the feet of the pallet
The system is heated with heating elements embedded in the mass of steel, di- vided into 8 zones in order to thermogulate the mass in a balanced way.
Another important feature in the molds is laminar vents. These are the layers of blocks which make up the components of the aluminum molds, which are present on the entire surface area, with laminar discharges from 0.25 mm to 10 mm wide, which flow into a large vacuum sealed container.
Even the flat lid which limits the platform of the pallet is made up of circular laminates (see Table 16), and is also connection to the same vacuum container. This millwork is achieved with holes that pass through the mould, and screws/bolts are then inserted (table 16 ref. 127). This allows the gas to exit through the holes and pass into the vacuum container (see table G2, ref. 16-17 "Injection system") and prevents any melt passing through. These discharges enable the flow of gas during injection, including the air in the cavities in the moulds.
The circuit is maintained under pressure during injection, and used for the opening of the moulds in order to maintain the position of the product. This means that we must open the moulds (2) at the same time after the cooling period, whilst maintaining the position of the pallet against the sides of the mould, therefore, when extracting the pallet, the pressure applied will help hold the position of the product.
During this extraction process and after opening the moulds, the pressure circuit can be bypassed by a two way valve, and can be contemporarily connected to a compressed 10 bar air circuit. This can be simply done using a double clip on the master controller which is attached using suction cups; a pneumatic ejection positions the pallet against the suction cups (kept under pressure), and through this contact the cups activate and attach themselves to the pallet, they are lifted to the conveyor belt and moved to the controlling and packaging area.
Using this type of circuit (suction/compression) helps to maintain the cleanliness of the degassing laminates from any wayward particles, which could easily find their way into the small cavities. Only gas passes through these laminates, but not the molten gases, because the contact on the surface layer cools the first layers quickly. The moulds are built using Avional aluminum (see Table G2 of "injection system"), a product that binds well and adapts to radical thermal changes, which makes it 4-5 times superior to its steel competitor. We need to use aluminum because of the rapid thermal changes in our machine, the fast and laborious workload, and the po- lished surfaces. Also, the internal parts are chromed or tefloned, in order to control the thermal changes whilst maintaining the hard and smooth surfaces.
These aspects allow: a speedy cooling process of the laminates strips that are in contact with the mould, so that no molten gets out of the laminate; it also means that the surfaces remain smooth and clean even along the ribbed area. The chroming is beneficial because it can extract even the most contaminated products (Soiled products, paraffin's etc)
As well as having vacuum containers (see table 16 section B-B), the moulds are also built with stainless steel contour lines at the joints, made with an interchan- geable method, which helps during maintenance.
The moulds are cooled directly by a closed circuit water ring, each with its own regulator valve.
In areas that need to be cooled more intensely, we use spiral swabs, which in- creases the exchange between the central return and the surface (see table 15, and note that the foot of the structure and the hard ribbing).
At least two different areas of the moulds will have mini pressure transducers, which will aid the positioning of the moulds into their respective presses.
During this injection process, the accumulator cylinder head will stop inject- ing, and the injection nozzles will close up.
This usually happens at BAR 70; a pressure level where we can be certain that the product is perfectly formed and compact.
All the double moulds are kept apart at approx. 550mm, using mechanical spacers with an enlarged head that will be fitted (see table G3 Ref.18-19 of the "in- jection system"); all using the aforementioned rail system, which allows us to guide and free up the any dilation in the hot runner through a dual fuelling system.
The injection process using "de-sprueing" nozzles (table G2, ref. 13 of the "injection system") is extremely useful because of the inserted into the injection system. It is made up of three cores: a) External section (cover) in stainless steel (table 15 ref. 123), standard made to allow the insert of the 12mm diameter stem bolt with a 22mm diameter bolt head cut off device, and allows the flow of non useable larger pieces to move through. This section ends at the head, with an oscillating conical seal at one end, and a lodged male insert leading to a smaller conical taper
(12mm) at the other end. This is placed into the insert using little interference, just enough to hold mechanical movement without the use of a seal. This end is held in position in the insert of the hot runner, using a quarter turn bayonet connection, and a group of four interposing axial undulate springs (which all allow axial movement and angular fluctuations in the section, as opposed to in the mould), against which each nozzle needs to be kept in position in order to prevent loss of movement when under the heavy pressure. Oscillation is allowed only because the two tapers are slightly different, therefore only at one point is the contact perfect.
b) The second section is the 12mm stem of the bolt (table 15 ref. 124), with a bolt head cut off device, whilst at the other end, a head made to connect to the hydraulic cylinder. This stops the movement of molten material once the mould has been fully injected.
c) The third section (table 15 ref. 1259) is the square hydraulic cylinder which moves the nozzles; a raised edge with isolated mechanical spacers at the hot runner, which includes magnetic sensors that detect the flow. These are made in aluminum and the stem is inserted into the stem of the nozzle and held in place using the bayo- net technique, preventing movement and dilation. The bases are made in stainless steel (Table 15, 16 ref. 126) and screwed into the injected semi mould.
In general, the nozzles allow the following:
The recovery of any differences during the axial process, keeping a strong seal at the tip;
The heating of the external section uses a compass with built in resistance and thermal fasteners that are easily changeable; - The recovery of any differences during the dilation process including any errors, all recovered by any permitted light angular movements;
Quick assembly/disassembly using the quarter turn bayonet system;
In order to maintain the heat of the oil at 50°C the power unit is cooled with a water filter.
It is extremely important that everything is held in place in order to deter any flow/molten loss, especially when there is heavy pressure during injection
This problem doesn't exist for the hot runner system, because contrary to the previous processes, the system, including its containers, is welded (see table Gl of the "injection system'), therefore, there can be no leaks.
On the stem and the external part of the nozzle, the seals are mechanical with extremely sharp tips, a = 12° circa, assembled with light interference, so that the in- ternal pressure (max 100-150 bar), presses the thin pointed edges against the base of the sliding stems, whilst the influence of the tips work much like scrapers/wipers in order to prevent any infiltration.
These tips, which create a seal, are about 2-3 mm in length; therefore the diameter can be reduced by 0.2 - 0.3 mm, to free up any movement needed.
Normally the moulds (with reference to pallets) are injected by 17 opposed nozzles (table G2 Fig. F of the "injection system"), this way only one hot runner is needed. They are offset in a way that each mould against each nozzle will be positioned slightly to the right or left, so that any flows of material will be balanced and uniformly distributed, where analysis will be continually carried out on temperature and pressure, in order to prevent any breakage.
The moulds are held in place externally by protected and amended steel plates (table G2 ref. 16-17 of the "injection system"), in order to avoid any direct contact with any of the tracks, hardware, or sliders etc.
As previously stated, the 17+17 injections are positioned on the nooks on the underside of the pallet, this way the platform remains free of any imperfections.
The injection is carried out in a way that with two semi-moulds and with just one injection, it is possible to produce a mono-piece pallet, including skids. We can do this by injecting 'male' skids into female inserts in the underside of the pallet, therefore, bypassing unnecessary assembly costs. By using a hydraulic cylinder tubes to power the unit, with cooling cylinders, separate power for the censors and resistance (using cables), containers and valves to cool the cooling equipment, and containers and valves for the vacuum/pressure unit used to open and extract the product, we are able to produce two complete double moulds.
The cooling process is carried out through simulation, as is the positioning of the nozzles, in order to maintain a temperature of at least 25°C/30°C in the mould, and throughout the aluminum mass cooling unit.
Homogenizing device (table II ref. II), charge accumulator (table II ref. 12) and the injection process
An extrusion unit used in the machine in this invention is described in tables A and B. This machine contains a homogenizing device (shown in table II ref II) and a charge accumulator (shown in table II ref. 12). The homogenizers in the Extruder are blocks of single/ double screws and counter/co-rotating cylinders that allow the ex- trader to blend the processible plastic waste. By using the correct compression ratio and mix, and adding any additives necessary, all is distributed into the accumulator cylinder head at variable volume and pressure levels (see table II ref. 12).
These parts are bought second hand from specialized markets. There at least two different degasser zones; the first extracts any vapor produced by the waste through humidity, the second takes in any cellulose degradation particles or paraffin's, or organic fermentation matter, or even solvents that are noticeable in the additives or inks.
Each unit is made up of two groups (see table II ref.l), of a raised cross section, and assembled onto a movable structure made of thick tubes i.e. scaffolding (ta- ble II ref. 14). This way they can freely axially expand, they are easily accessible and thermally protected.
Each has its own reducer (reduction system table II ref.13) and both are powered by a single variable motor, situated in the inferior part of the scaffolding so that they are easily accessible for maintenance purposes.
The cylinders contain centralized oil heating in at least 6 different areas, all with their own control points.
This system guarantees a balanced heating profile.
The two groups are powered by fortified vertical snail shaped hopper (table II ref. II). In table II, reference 12, it shows the double storage device. This device is used to accumulate the injection dosages' in the mould, and can be worked automatically using variable pressures, depending on the parameters needed. Therefore, it can inject different types of moulds and at different intervals (maintaining different pres- sure levels) right up until the moulds are finalized. It is connected at one end to the extruder, where it receives all the molten with added additives that homogenizes at the correct temperature, the head and the core of the hydraulic cylinder are blocked by a single support system, which proceeds into two separate supports (see table II ref.I6). Each can axially move (at the start), to allow the expansion of the homoge- nizers, and may be manually blocked using a spiked framework.
The double head is there to maintain the timing of the injection at 12"-24" at 18 Kg / each, operating with a pressure load of about 30 bar to restrict any gas and injection build up, using a manageable pressure program and proportionate valve. This way we can manage the filling and maintenance whilst the load is injected.
The implementation of the hot runner, the routes of the flow containers and the disjunction valves can all be assembled with ease. The idea is to reduce pressure by at least 50% which means that the pressure during injection will be significantly lower, thus reducing the energy needed to pump the central unit
- Scaffolding/walkway
Table II, reference 14, shows the moveable steel scaffolding which supports the homogeniziser, the motors, the accumulator cylinder head and anything else that is connected to the unit itself. It has a 2 stairwells, thermal safety barrier, chromed railings, accessories for the additive hoppers, degassing vacuum, grilled walking frame, and an anchorage for the press and reducers.
- Disjunction valve
In tables Dl, D2 e D3 we can see the connection/disconnection device that leads to the extruder. This device is called the "disjunction valve".
The disjunction valve is indispensable in this type of machine where the injec- tion system needs to be independent from the moulding system. A moulding system which uses a double mould and only 1 hot runner, can work with various shapes and volumes of moulds at the same time, and where the quick movement of the moulds (or the injection system) to the cooling areas reduces the working cycle. Valve characteristics:
• Made up of two separate vertical modular bodies (see table G02 pos.3)
• The inferior body is anchored to the moulds and fixed tight in place, in line with the hot runners' power container.
• The superior body is anchored and fixed tight to the press.
• Both can easily be linked/separated because even with some thermal dilation or power errors, all is compensated by its overall performance (Table G02 ref. 2).
• As the inferior body is fixed to the mould, it will always maintain its alignment with the scraper collector (2) end (see Table II).
• As the superior body is fixed to the press support, it will stay aligned with the inferior part, as long as the moulds always hold the same position during closure, even if it is geometrically different. There will be only 2 for each homogenizer units.
• In order to compensate the loss of any load into the valves, all passageways are 100mm internally as opposed to 80 mm (measurement used in the containers).
• All the body valves are made in stainless steel with input/output feeders using ring shaped scraper seals.
• The areas around the scrapers are also in steel. The scraper rings seals are in aluminum bronze, that are hard, easily assembled and are held in place in a way to allow axial movement and very little angular dissa- lignment. .
• Both bodies have hydraulic controls (cylinders with diam.63 track of 110mm) that are isolated by thermal mechanical spacers with quick connection fits to the stems, a mechanical sealed lipped scraper.
• The two cylinders control the internal parts, opening/closing ends - linkage/disconnection; joined at the opening end (table G02 pos.2) to allow the flow of the product that needs to be injected, a 110mm passageway, linked together at the closing end (table G02 pos.l), intercepting the flow and separating it all at the hot runner (flow passageway) from the accumulator cylinder head.
• This interceptor is a mushroom shaped bolt stopper with a 100mm diameter, made in stainless steel, and is used as the only stopper for the axial link.
• The two cylinders work in tandem, working the respective opening and closing ends in fixed strokes. Using two cylinders means that the correct amounts of strokes are guaranteed.
• An important aspect of the valve is the connection device which is fixed to the inferior end of the body, and as you can see, swings, which allows the following:
The recovery and adjustment of the cross-section should there be any light misalignments in the two bodies caused by expansion.
Adjustment of any axial positions, where any slight differences are compensated by springs (set of springs) that are more or less compressed (table G02 ref.2).
Adjustment of any slight angular differences in the two axils, again due to the presence of the springs.
The most striking aspect, however, is that these normal axial movements that are permitted by the swinging seal, don't give rise to any losses.
The inner double-ended ring is heavily engraved a = 12° (table G02 ref.3), which allows these adjustments, giving that the material used is very elastic.
Altogether these essential components allow the following:
· The alignment in entering/exiting the accumulator cylinder head and the hot runner container
• The expansion of these two components whilst retaining the hold of the molten
• To separate the fixed parts on the press from the static parts, which are embodied on the mould, without loss or leakage of the melt?
• Disconnection in this case is made up of a few mm - max 200mm; therefore the press needs only a few strokes, even with different moulds, at low closing and power costs. • Heating up the ring right through to the base aids the melt flow for later cycles
• The bases are changeable, therefore should there be any unrepeatable wears or tears, and they can be directly substituted.
Overall, everything is made of materials, tolerances and concepts that allow small misalignments or slight differences in the execution of position, without causing interference or malfunction.
The thermoregulator is made up to 2 independent heating areas.
- Thermal coupling (table 13)
From the end of the accumulator cylinder head to the entrance of the disjunction valve, there is a thermal coupling (see table 13 and II).
The design shows how it works. This important element is there to connect these two extremities in order to allow slight differences in axial movement caused through expansion.
As seen through this coupling (table 13 ref. 118), which is made of a fortified, grounded and incisioned steel spring, which is set in between the two hardened and ground stainless steel interchangeable screws (Table 13 ref.I20, 121).
Altogether through its ability scrape through the internal surfaces and transversal warping, this coupling allows:
· Axial expansion of the components, especially in extrusion with at least 10mm of dilatation.
• Angular offsets of small value.
• Cross offsets caused by different positioning or expansion in the accumulator cylinder head container.
· Altogether this process eliminates any holding problems, in any conditions and at melt temperatures.
- Portal Press (Table 14), also known as "portal station".
Table 14 (also in Table II Ref. 17) highlights the functions of the two presses, with a closing capacity 1500 Ton/each.
This allows max dimensions of 1400mm of moulding and 20mm strokes on the lower level (mould loader - table 14 ref. 112), which in turn allows the development of mould packaging. The maximum size of the mould surface is 1500x1500mm. The following characteristics describe the press:
The concept is simple, made up of 1 inferior base (table 14 ref. 113) with a moveable superior structure (table 14 ref. 114), both the same shape and same measurements, 700mm thick, which allow the closing of the mould to reach max 1500 tones.
The two 700mm portals are held up by 4 rectangular columns (Table 14 ref. I 16), each 400x250mm, which keep apart the two structures and can support a traction total 375000 Kg each. The ends of the columns are made in a way that the axial tractions uniformly fix themselves in all of the cross-sections, in a way that they will not generate any components that tend to deform the columns themselves, i.e. axial curving (see also the grafts, table 14 ref. 113).
The mobile level of the combination mould, (which is already closed), to be packaged, is made as visible in table 14 fig. B, 250mm thick, and is raised up by 4 hydraulic cylinders, and simply held in place with plungers, on the same level, with an external diameter of 380 mm, and powered by the hydraulic unit.
The positioning of the stem centering cradle (table 14 ref. 117), allows the swift raising up of the mould whilst maintaining the axial uplift.
Small differences in the structure of this level are offset by the round head pistons, which allow small inclinations of this level.
The weight of the opposing springs (at least 10 tons) allows the level to return to its correct position.
Conceptually, the technique to separate the power supply circuit of the melt from the mold, and also shut off the circuit whilst charging the accumulation cylinder head, allows continuing loading of overlapping phases of the accumulation cylinder head, from the homogenizer and simultaneously bring the closed injected mould back into position for extraction (flow of 20 mm max), all with a single coaxial double shutter valve.
The moulds (max 8), are radialy placed 45° from each other on their own 1500x1500mm mould loader, with rolling inserts and 1650mm strokes, all driven by radial cylinders which engage/disengage the moulds for injection in a very speedy process (Table 12).
The 20mm tract (short) is necessary to close the moulds shut while also disconnecting the two circuits, this helps the stems stay attached to the cylinders of the mould loader, accelerating the overlapping phases when the mould is radialy positioned.
This rolling system is guided by the mould loader of each rotating arm and is fixed to the press (Table 14 feature C), which in turn allows a rotating transfer of the moulds from the press rotor.
The next time the mould is closed, again with a brief 20mm tract into a fixed position, allows the axial link of the conical part of the valve that has been thermally treated, which fluctuates to compensate for any small misalignments or any differences in the thermal expansions in the container.
At the injection side of the press, the undercarriage container of the hydraulic circuit is positioned, including all electro valves, which are also under the base, and powered by the hydraulic central unit positioned under the carriage. This is powered by flexible tubes, this way the press may be independently set-up, including the insertion of the electro-hydraulic board.
With this concept, the press may be raised/lowered using only the prismatic columns, therefore, the press is a simple build and can be constructed as needed, varying only the columns. As it is made up of rectangular sections, all the units around are easily assembled, side rollers, hardware containers etc.
- Fixed hydraulic unit.
A flat surface, with a tank and motor placed directly onto this surface, with a roller guide that is on the ground underneath the scaffolding/walkway, this way keeping a balanced stance in relation to the fixed machinery.
It can extract via the rollers, in order to make any maintenance easier.
It is connected to the container (valve at the base), using loading/unloading flexible tubes.
This way it takes on a constant position with the scaffolding/walkway, whilst maintaining easy accessibility.
Therefore, despite its positioning and flat surface, the central unit is quite unique. The motor has variable speeds, so that it closes shut quickly to reduce the need for maintenance. Basically the motor absorbs energy in proportion to the amount it actively produces. Power is dispersed from passive work from the laminates (creating heat); the turns in the cycle are automatically reduced, so that any oils are energy is thus dispersed into heat.
Power is created by: • 2x 220 mm diam. accumulation cylinder heads.
• 2x 4 cylinder motors closed by the press.
• 2 fixed cylinder disjunction valves.
• 1 fixed positioning cylinder with a shutter at the rotating mould loading system (central).
• N°2 cylinders, to open the moulds.
- Rotating mould loading system (Table II Ref. 17), also known as the "carousel".
The basic function of this component is that it allows each mould (Between 4 and 8) a radial exit for injection, and the opening, closing and extraction of the mould itself.
These means that it can work in two fixed positions.
Injection starts at 4900mm from the centre of the mould, whilst the mould is anchored to the rotor by a radial cylinder with a 1650mm tract (table 12).
The rotation of the mould (injection system) starts at 3250mm form its axis, with the mould in a pitch diameter rotation of 6500mm; therefore, there the moment of inertia is controlled (minimum for mould positioning).
The rotary is octagon in shape (or hexagon etc), made from steel, and each side is anchored in an oscillating mode (Table 12), with 4-8 rigidly hinged arms, but with the possibility to adapt the machine without creating any problems for the support etc.
The body of the octagon (table II ref.I7 - this image shows the 6 mould version), also known as the hub, is supported by flat iron-plated basement structure, which is held in place by anchor bolts that are inserted into a cement plated pavement (table II ref.I8).
Both bodies, fixed rotating octagon (or hexagon etc), form a single unit with an interposed toothless 1750 mm washer (large double ball bearing).
This rotating component reduces mechanical friction to a minimum and acts as a thrust through the weight of the rotor.
The sides of the rotor (between 4 and 8 - ref 17), also have central fixed structures that hold the toothed crown section, this controls all the rotor using a dual vari- able speed gear motor, including all the closed moulds, through acceleration and deceleration of the mass.
In this manner and using the same amount of power, needs a lot less torque and creates a more regular and balanced movement. The motors are inserted into the outer mass of the rotors, to facilitate maintaninence.
The ends of the arms have rotating supports made of 6 silent nylon wheels, which help hold the moulds stationary, that are themselves held in place by radial cylinders of different heights, so that during rotation no lifting is create.
When the rotor is positioned into a central position by the radial wedge, the two mobile rollers are fixed to the press (Table 14, figure C), they are then lined up in a way that the mould can be shift without rotating form the rotor to the mould loader (table 12).
Gravity holds the heavy moulds in position, they weigh roughly 10-12 tones, but no there is no safety issue due to the 'C shaped security tracks.
The arms are hinged so that no stress is put onto the rotating structure, especially should there be any parallel abnormality between the rotary support and the fixed rail tracks.
Each swinging arm is supported by 2x250mm diameter fixed wheels (table II ref 19), which support the weight and roll onto the ground level tracks. This way the internal rotor and its arms become a compacted unit, which is powered by 2 pairs of external motorized pinions with a crown pitch diameter of 5000 mm, whilst the system has all the flexibility it needs.
The lower external parts of the octagonal port arms (table II ref. 17) contain:
• 2 small scale hydraulic units needed to control the mi- cro nozzles for each cylinder of the mould, the positioning cylinders on the moulds, and the cylinder on the inferior part of the disjunction valve of each mould, which is connected to the fixed valve on the press and in turn connected to the accumulation cylinder head.
• The closed loop containers of the hydraulic unit which can power the hydraulic circuits through protected flexible cables.
• 1 traditional 10 bar air compressor, with ringed air accumulator, to aid the extraction of the mould during the extraction process; this final double extraction phase is helped by rapid expulsion caused by the air compressors against the two pallet moulds. • 2x water looped vacuum pumps with their own containers, which create enough suction in form a pressure ring, designed to achieve the extraction of any gases during the injection phase, whilst the circuit keeps the pallet in position when the mould is opened.
Both the vacuum and air compression circuits are intercepted by a common 3 -way valve, which functions to include/exclude either or circuit depending on which operational phase is in progress.
The octagon (table II ref.I7) also supports the positioning cylinders of the moulds, which are supported and hinged to the centre of the arms.
At the centre of the octagon is, which is flanged to the fixed base, there is a hollow shaft (table II ref. 110) which carries out the following:
• Suction from the centre of any gases caused by laminate degassing discharged through the vacuums pumps.
· Water connection between the external refrigerator units that cool the water circulation in the moulds.
• On the most external parts there are:
1 container that distributes water to the double moulds (4-8), with a cold water branch pipe and a hot water return pipe.
1 three phase 380V electric container that powers the onboard circuits and heats the hot runner system and the nozzles of the moulds.
1 exhaust gas container which collects any gases that are expelled by the vacuum pump into the hollow shaft during the injection phase.
In summary, these containers are compressed air tanks that distribute a vacuum circuit during the injection, opening and extraction phases, which may be intercepted by a 3 -way valve in order to alternate suction and compression in each mould.
Flexible extendable 1650mm cables and pipes used are.
These pipes are protected and fixed to the external parts of the arms. Multiple sockets are used for all of the water connections, the loading/unloading oil connections to the injector cylinders and the heating to the injection system.
By looking at table A, ref.7, we can see more specifics on the rotating mould loader.
The concept of overlapping different phases during the moulding cycle reduces the length of time dedicated to each final product that is made.
Using this double mould system effectively doubles production when there are two injection systems in place.
A traditional one mould press cycle of 144 seconds makes 25 pieces/hr at 18 Kg, which is 450 Kg/h of product.
This machine has a 43 seconds injection cycle, as long as we inject using 2 accumulation cylinder heads, the mould is already closed under the press (track of 20 mm) and the melt load is integrated simultaneously with the non-stop homogenizer.
Cooling takes place in intermediate stations, and during the movement, opening and extraction of the product, and also in the press during the injection interval.
To further speed up the injection process, the hot runners have high flow systems, and the mould cavity under is vacuumed in order to prevent any gas back pres- sure.
All the moulds are independent and can be shaped differently, including different weights and measures.
Therefore with an extremely high performing machine we can simultaneously produce a full pallet program, even if there are different pallet requests.
Production levels reach 84/h x 2 x 2 x 2 = 336 pieces/hr, therefore 13 times more efficient, with a transformation level of 6.050 kg/hr, as opposed to 450 kg/hr of a traditional mould machine.
All low tension signals are managed through a radio frequency system (induc- tive censored tracks) with thermo-coupled temperature controls on the injection system.
The water source supply and discharge onto the moulds is created by the closed circuit fridges and the supply of energy from the electricity network to the moving parts through the coupling system. This means that we can avoid any dan- gerous connections or complicated assembly or maintenance, and instead insure function ability and rapid industrial assembly.
As mentioned there are multiple adaptor plugs used in connecting on the moulds, whilst multiple coupling units are used on the hydraulic circuits and the wa- ter loading and cooling units.
The release of pressure in the moulds (4-8) is carried out at the end of each injection cycle to save on costs. Censors are plugged into and positioned onto moulds in a way that the radial positioning of the moulds themselves can detect when pressure needs to be lifted, and in turn the cycle may be stopped.
All the rotating containers are assembled so that planned maintenance is easily followed through.
- Opening/closing device, and the extraction of the product (Not visible in table in.
Each mould has a steel plate which contains two semi moulds, 450 mm thick when closed, and between the two moulds a standard injection system is inserted which is made up of:
• Central hot runner with relative hardware
• Double injection nozzles 17x2 = 34 with quick connectors
• Opening/closing cylinders which are fixed to the hot runner · Mechanical spacers
• 2 disjunction valves, with inserts.
The extraction of the two pallets entails the opening of the moulds to at least 500 mm, or least so that the mechanical arm (with suckers) can get in, so that through this suction they can be lifted and brought onto the conveyor belt that leads to the packaging area.
The opening of the mould is carried out radialy at the press. This can be done even with double and simultaneous injections.
This concept has been built to create competition with the wooden pallet mar- ket, which currently takes up 95% of the worldwide pallet market. This means that with one vertical movement we need to open both the semi moulds (500 mm) at the same time, but because this forms a single movement on the sides of the mould, the vertical movement of the upper semi-mould need to be increased to 1000 mm. This is understandable because the lower semi-mould is connected to the upper mould through the injection (mechanical spacers) visible in table G2 fig. H of the "injection system".
Here is a description for the opening device. In order to follow through with a single rapid movement to open and then extract the product, including the radial movement, entrance and exit in less than 40 seconds, we have created a mechanical system which uses an upper cart which doubles the base capacity (therefore, from 500mm to 1000mm).
The opening device consists of:
a) A 'C shaped double guide on each side assembled and positioned in line with the presses position, which is anchored to the ground just like the press. The structure has a two-way rolling guide positioned so that it allows the mould to be lifted.
b) Double lifting device at the sides of the moulds is made up of two separate instruments:
• The lower part of the device is a guidance system to rolling guide and another fixed guide, which is positioned by the radial cylinders that allows the mould to fall into place to be opened. It also has an 80 ton hydraulic lifting device, which can lift both semi- moulds as a first load. This lifting is not only about lifting the moulds, but it must also have the power to extract the 2 pallets from the two opposite semi-moulds. This is a closed ring hydraulic movement which helps parallel lifting.
• The upper part of the device cart on the two 'C shaped guides, with double rolling instruments. The cart contains an incorporated elevator system, that when lifted by the lower hydraulic system, allows the axial linkage to the 2 gauge lines that are fixed to the structure, in order to a second lifting process of the upper semi-mould of another 500 mm in order to extract the 2 pallets.
When open, the instrument is roughly 3550 mm in height (see design), and the lifting devices are made in a way so that the press is centered with the semi-moulds during lifting (restraining plates). An extraction device e seen in Table II refil l and is made up of an articulated manlike arm with double gripping equipment, using suction cups formed with needled valves.
These two instruments, transversally, can carry out combinations of free large movements, so that they may be perfectly positioned using the compressioned air against the pallets.
Whilst the master controller positions the pallet onto the conveyor belt, the instrument closes, as do the moulds, to return to their correct positions.
This master controller is made up of a vacuum pump and an independent elec- trie box which is linked to the general control system inside the machine.
- Auxiliary machine equipment.
Other auxiliary components of the machine are:
• General Electric box inside the machine.
• Command console.
· Dust filter machine.
• Gas suction processing machine.
• Waste pretreatment machine.
• Silos for mixing and storage.
• Fluidized-bed dryers.
· N.2 refrigerators to cool water.
• Water containers/treatment devices for waste and pallet storage.
• Raised control booth.
• Carter guard.
- Operating cycle in standard trim with 8 moulds and 2 homogenizers.
The following is a description of the operating cycle in standard trim, which is essentially how the cycle develops, considering that all the components and equipment is in full working and productive order.
The two homogenizers can work between them 6350kg/hr of product, almost 1600 kg/each, considering that there are 4 screw cylinder groups in total, 2 for each homogenizer.
This total includes the 5% of converted vapor (humidity) and various gases that are extracted. There are 4 accumulator cylinder heads, each with a max injection capacity of 22kg. A 429 mm track is needed, which is 68% of the overall weight of the pallet (18 kg).
We can inject 1.36kg/sec into each head, equal to 47, 5 mm circa track, with a constant injection speed of 9 seconds. The remaining 5,776 kg are simultaneously pumped from the extruder during injection. It is maintained for another 4 for pressure.
The first phase of injection is carried out with the melt that is injected by the accumulator cylinder head 12.23kg, plus the equivalent from each homogenizer of roughly 4kg, which lasts 9 seconds.
The remaining 1, 78 kg amount to the second phase of injection, carried out solely by the extruder, and lasts 4 seconds, the same as the filling in of the moulds.
Compacting and maintaining are slower, roughly 0, 4444 kg/sec, which reduces the turnover in even lighter loads (this is all evaluated during testing).
Overlapping cycles during these pauses are the following:
• Partially loading the accumulator cylinder head to 68% of the overall weight, occurs when the rotor is released and locked, the rotation of itself and when the moulds are inserted/extracted etc, this takes 27 seconds.
• Opening/closing phase of the mould, extraction of the pallet, collecting/handling of the pallet, insertion/removing and rotation.
• Injection is carried out in 2 phases: the first with accumulator cylinder head and the homogenizer; and the second only with the homogenizer.
• The cooling phase is continual and lasts about 50-60 seconds in order to reduce the temperature in the centre of the depth of the product from 200°C to 70°C, this way the residual temperature is inferior to a vitreous transition. This is a necessary process because before the opening of the mould at least 120 seconds pass by; this is the timescale between injection and extraction.
· All of three phases are simultaneous and are never more than
40-42 seconds.
The two homogenizer systems work simultaneously.
The machines productivity levels derive from these operating times. - Production level of the machine.
We can gain the following a maintained and fully tested machine:
• Repeatability from both injection systems, without any defects.
• Excellent injection capacity on all mould types.
· Planned and defined maintenance schedule.
• Good superficial appearance for the pallets.
• Tried and tested technical and mechanical characteristics.
• Machine with an environmental impact, at rules and regulations standard.
· Well trained staff that has been onboard for some months, therefore, they are familiar with the mechanisms of the machine, including the injection and extraction processes.
• All secondary information regarding the machine is already well known.
· The console operators are well skilled and familiar with the machine, and are able to intervene without assistance if necessary whilst the machine is operating, with the mix, or the turns, timing, or pressures etc. Under these conditions, although the homogenizers never stop, and it turns at a continual and constant speed, the loading at the head which is the equivalent of 68% of the pallet, occurs during the movement of the rotating core and of the mould, as well as during the cooling period, and is only really restricted from the start of injection to the extraction process, caused by larger timescales than necessary.
Cycles that restrict the machine are:
A) Injection. The most important part of the whole process, which determines the speed of moulding, the quality of the product, and when the product has been homogenized enough, includes its degassing process (1600 Kg/h/each).
The reduction of this phase to 40-42 seconds depends on:
The speed capacity of accelerator/decelerator of the rotor; therefore a low-torque motor is used (with external command) in the mould loading system.
Its fast fixed positioning, with positioning device (50 mm track), in a way that each arm is positioned in line with the press, and therefore the 2 disjunction valves. Quick radial Insertion/removal of the moulds with a hydraulic acceleration deceleration phase.
A tract where the mould is quickly closed, max 20 mm, and simultaneously grafting of the fixed disjunction valve.
° The opening of the nozzles (17+17) which unload roughly 1 kg/each of melt into the moulds.
2 accumulator cylinder heads are needed in order to carry out the injection in 9 seconds, therefore 12, 2 kg.
° Never stopping the homogenizer, slowing it down or increas- ing the speed will only harm productivity. It integrates the mass from the accumulator cylinder head, 4 kg in 9 seconds, which is the same as the final phase, 1 , 8 kg in 4 seconds.
The two homogenizers being made up of two screws/cylinders, therefore one for each accumulator cylinder head, powered by the same motor. This way it is more flexible and there is a more direct homogeni- zation of the system.
All of the internal melt flow, including in the moulds, should be perfectly covered and chromed in order to reduce the resistance of the flow, maintaining a constant flow.
° The moulds are depressurized by a pump that not only vacuums all of the gas emissions, but can also reduce the internal pressure, and help the flow rate.
B) Opening of the mould-extraction of the product-handling. All of this must be carried out in 40-42 seconds, and be in position before the injection process be- gins again at the press, whilst staying attached to the cylinder at the base of the double mould system.
Even at this stage the requests of the rotation rotor, locking/unlocking process, and the radial insertion/removal of the mould, are detrimental, but what is fundamental is the simultaneous extraction and mechanical opening of the moulds (N.2 inde- pendent), each at 500 mm one above the other, so that the twin-instruments used in actually extracting the product through depressurizing can carry out their task, and then the subsequent closing shut of the mould for the next injection. The phases in this cycle are as follows:
The injection cycle is as follows. During the loading phase of the cylinder head, 429 mm in 30 seconds, the nozzles are closed, the valve is separated, the two arms of the cylinder head and of the hut runner are separated from the divided disjunction (bolt diam. 100 mm).
Once the radial position is assumed and subsequently the mould is closed shut, there is a 3 second wait, therefore the injection phase starts with:
° Opening of the nozzles - 1 second
Injection command from the cylinder head 9 seconds, constantly fed at about 48 mm/second (12, 2 Kg).
At the same time, 4 kg are integrated from the homogenizer without slowing down.
° At the end of this cycle, the piston is fixed into position.
The homogenizer stops injection and compacting for only 4 seconds which allows the pressure to rise rapidly in the mould to 50-70 bar.
One second before, compacting is simultaneously achieved, the piston form the accumulator cylinder head is ready with the next load, and the injection nozzles are closed.
After the nozzles close, the piston rapidly jolts back by 10-15 mm, and sends the flow into depression.
After this jolt back, the disjunction valve closes, so that there is a low pressure in the hot runner in order to prevent infiltration.
This jolt back in the piston is caused by back pressure of 30 bar, in order to maintain a low formation and concentration of gas in the mass.
After the disjunction valve closes, there is a two second wait, and then the second press opens.
The radial extraction of the mould is maintained shut without any losses. This is because immediately after and also during injection, the flow rapidly drops to 200°C (huge temperature change) with the aluminum mould, which helps the pressure fall to 50-60 bar in a few seconds. The weight of the semi-moulds is sufficed to prevent any infiltration below the closure level. The opening of the mould comes as follows. Simultaneously as with injection the rotation, locking/unlocking and insertion/removal of the moulds, uses the same amount of time. The vertical hydraulic opening is managed by a proportional valve, which aids a variable speed of flow. Once the opening cycle is complete, the arms with the double suction cups are oriented and they are pneumatically brought together.
This way the pneumatic expulsion of the pallet, which is pretty violent, pushes the two pallets against the suction cups. This pressure level helps the suction cups press against the upper part of the pallet. Once this phase is finished, the pneumatic equipment is repositioned to extract. The master commander can then rotate and position the pallets correctly, to be piled and packaged. Once the equipment is out of the mould, the mould can then be closed and radialy repositioned.
- General product characteristics.
The presence of gas in the manufactured products is gradually released once they are put into place. These gases are reduced by continued degassing (homogeniz- er) and in the moulds (depressurizing), and this helps not only reduce back pressure, but also the remixing caused by gases in the melt.
• Greatly improves process ability and reduces (annuls) defects in complete injection cycles. If the presence of gas isn't eliminated correctly, it can behave like an internal bubble that moves and compresses, heating up continually. Not only will this slow the injection process down, but it will not permit a complete cycle.
• This deficit moves into various areas.
• Hot gases will provoke burned opaque areas, creating uneven and varied surfaces.
• They will not allow a regular flow of the melt.
• They cause fractures in areas where the flow meets at joints, and provide a poor binding quality, mainly because these areas are separated by the interposition of gas and hot air.
· They reduce the capacity of drastic thermal changes, especially the cooling process, therefore creating high non homogeneous abilities.
• Injection in the undercarriage of the pallet will eliminate any defects on the platform itself, caused by the "de-sprueing" nozzles (17), and it also means that those annoying circles caused by the melt are also not visible on the platform.
• It allows a full non-slip even platform of extremely high quality, with great mechanical traction resistance, impact resistance, flexibility, elasticity that is only 25% inferior as to when virgin raw materials are used, and all compensated by a thicker and slightly taller product.
• By using the double depression compression circuit when extracting the product, we can avoid the multitudes of prints and points left in the product when using the traditional box extraction. This traditional method is also a source for gas leaks and product wear and tear, which also includes external extraction devices, something that is extremely difficult to use in double moulds.
- Conclusions.
This tested machine therefore provides the following:
a) Higher performance ability opposed to tradional methods, 13 times superior, producing 336 pcs/hr.
b) Low transformation costs, therefore it is extremely competitive at O. 15 euro/Kg.
c) The cost of the machine is only 2, 5 superior to the traditional one.
d) The quality of the final product is on a par with that of one that uses virgin raw materials. This is because during storage and usage of the waste, the degassing and deodorizing processes used eliminate all bad odors. e) Just one machine can produce an entire lot of products, prod- ucts which may be different in size and shape.
f) By using two opposite homogenizers, the machine may be built in two separate phases, allowing a gradual development, and therefore a slower rate of investment.
Overall, other than creating a new font for the use of post-use heterogeneous plastic waste, waste that normally is sent directly to landfills or incinerators, this advanced technology is also an astute business possibility, especially in sectors where common interests in environmental issues are at the forefront, such as local governments and the environment sector itself. The re-use of non degradable plastic materials is something that we must seek to concur, because in an entrepreneurial and economic sense, it makes for good business.
Detailed description of the connection/disconnection device
This device is an innovation in the plastic moulding industry, in that it allows you to separate the injection circuits from those of the mould. This system is particularly effective when used in the carousel type machine described above. Once the injection phase is finished, this device enables the closing of the two circuits, thus eliminating melt loss, whilst the moulds continually move on the carousel.
- Brief description of the designs of the connection/disconnection device
The device is visible in tables N.D01, N.D02 and N.D03, the particulars are the following:
• Table N.D01 shows the exposed version of the device, highlighting all its components;
· Table N.D02 shows how the device actually works, and the positions the various components take up during the different phases of moulding.
As you can see, position 1 corresponds with the mould when in the injection position, with the upper part of the valve joint to the press (ref. D7, D8, D9, D10, Dl l) making a perfect mechanical seal the lower part of the valve, also joint at the press.
Position 2 shows the device in the same conditions, but with the flow runner open. The two shutters in particular move in unison whilst connected at either end, suffering a vertical translation which opens the flow of the molten materials.
The third position shows the device once injection is finished. The melt flow is closed by the translation of the shutters in downward movement, which however are now separated, along with the cores of the valves. The upper valve core is pressed against the press and joint/fixed to the accumulator cylinder head, whilst the lower valve core which is pressed against the hot runner of the mould, is lowered in line with the flow of the press, and in turn, the valve is separated and therefore the flow to the mould.
• Table N.D03 shows the details of this valve.
-Detailed description of the embodiment of the connection/disconnection device The work plan of the invention is based on the opening and closing of the two circuits:
- The first circuit is where the melt flows from the extruder to the upper group of valves, right up to the upper fixed flange, ref. D9. In this circuit the ma- terial, whether it may be virgin plastic, homogeneous plastic or even post-use heterogeneous plastic, is heated and mixed by the homogenizer, which is then turned into melt at roughly 200°C. The melt then leaves the homogenizer and is sent to the accumulator cylinder head, where the correct amount is inserted as to inject the correct amount into the mould. The accumulator has a hydraulic piston which violently injects the load into the mould, at a pressure between 120 - 160 bar, until the mould is correctly and fully filled. Therefore, the first circuit contains the extruder, the accumulator cylinder head and the upper group of valves (ref. D10, Dl l, D7, D8, D9, and D 12).
- The second circuit contains the lower group of valves (ref. Dl, D3, D2, D5, D4, and D6) which lead to the hot runner container, the hot runner itself, the nozzles and the mould. This second circuit first receives the melt during injection before sending it to the mould.
In general, the moulding cycle is made up of 4 phases:
1. Loading of the accumulator cylinder head.
2. Movement and injection.
3. Cooling of the mould.
4. Opening of the mould and extraction of the product.
Using a traditional moulding machine means a frontal injection from the press to a single mould; these phases are not separable, which means a low level of pro- duction from this machine
Using this new type of machine, through rotation and as described above, these phases may be divided, thus creating a higher performance driven machine. Once injection into the mould is finished, it is placed onto rotating drum, and the mould loading carousel rotates just one position (45°-90°) and a new mould is placed under the press, and all this happens while the extruder continually sends to the first circuit (described above), and the accumulator cylinder head is loaded and ready for injection as soon as the mould is in place.
Using this method, where the injection system is inserted directly into the mould, there is no need for the points of injection to be moved into position. This is because there is only the one injection font which is fixed to the upper part of the opening of the press.
By using this method of injection system, although it costs more, it is possible to install onto a rotating (or non) machine, as long as the melt can be received via the accumulator cylinder head, as described above, limitless different types moulds,.
This comes about in the connection of the two circuits and the idea behind the development of the connection/disconnection device.
This device, that is subject to this new patent, is necessary in order to disconnect the two circuits in a way that the injected mould may be sent to cool down, whilst a new mould (empty and ready to be injected), can be put under the press and ready for injection.
In order to connect and disconnect the two circuits, the connection/disconnection device (also known as an oscillating disjunction valve) needs to have the two following characteristics:
1. Able to stop communication in the two circuits with opening and closing valves, using two stems with incorporated shutters, ref. D2, which guarantees a perfect mechanical seal which will not allow any loss of melt.
2. Ensuring the coupling of the lower and upper valve groups which can adapt to small alignment differences, to compensate any errors that may occur in the alignment of the mould and the press. Remembering that the moulds are inserted onto a carousel that may hold up to 9 moulds (theoretically there is no limit to the amount of moulds, but if more moulds are needed, it would be better to construct a new twin machine), with diameters that may exceed 10 meters. The moulds that are inserted into the rotating machine ("Rotating machine with mould loader"- which is also waiting to be patented), are inserted and removed from the press in a way that all the advantages that are aforementioned can be taken into consideration. All of these movements and couplings are difficult to carry out, even with strict care during each phase, but they guarantee the perfect alignment between the group of lower valves which is joined to the mould and the upper group of valves which is joined t the accumulator cylinder head. This is why the valve in question is oscillating; thanks to its particular shape it allows a few degrees rotation and translation along the vertical axis, to ensure a complete coupling between the lower and upper groups.
The seal between the two valve groups when the disjunction valve is connected (position N.1 and N.2 table D2) is mechanical, and made up of two circular elements (ref. D4, D9), which thanks to this peculiar shape, are only in contact along the circumference, see table TAV D03.
In order to allow the valve the possibility to adapt to different positions between the lower and upper groups of valves, the lower part (ref. N°D1, D3, D5, D4 e D6) is made up of two separate linked parts. The lower part of this is runs to the ap- pendix of the hot runner container, ref D01, and the upper part to the lower tube on the mould, ref. D05. These components are turned onto the internal diameter so that they may couple with the plated seal, ref. 03. The latter is shaped in a way so that it may deform under the lateral pressure, generated during the joining stage, and when the two valve groups are not perfectly aligned, caused by small differences in posi- tioning, ref. D05, caused by the pressure from the set of springs. Using this method, and assuming that the mould, hot runner system and its container (ref. D01), remain stable and not deformed, whilst the lower core valve and most notably its components N.D04, D05 and D06 may incline and translate in a vertical direction, right up until the perfect coupling with the upper valve group (to be precise N.D09 compo- nent)..
All of the mechanical holdings of the components N.D10, D09, D04, D03, DO 1, are achieved through the same lipped system, see detail A, in table D03, which shows that near the end of the outer diameter is turned to tolerate. This is carried out on one or more loads on the exterior of the component, which will eventually weaken itself in entirety. The component is then put under pressure by the melt flow circuit (30-160), which tends to flex in the areas closest to the dugout throat, and it sticks more to the internal wall of the component, which it is already coupled with; therefore creating more internal pressure, more flexibility in the ends of the component, strengthening the internal diameter, and restricting the loss of melt even during high pressures (160).
As visible in the larger version of table D01, the thin platted seal is inserted at one into appendix of the hot runner container, ref. D01, and the other side into the lower mould pipe. This thin platted seal, ref. D03, has a supported surface which is cut out from the external diameter, which is moved from underneath by the set of springs, ref. D02, and from above by the movement from the lower mould pipe, ref. D05. This way the thin platted seal is continually pressed against the lower mould pipe. In order to keep the device closed, which under pressure from the springs would normally try to open itself, a lock nut is screwed in between the lower mould pipe (ref D06), and the appendix of the hot runner container (ref. DOl). Detail B of table D03 shows how everything plays out between the fixed flanged mould pipe, ref. D06, and the lower mould pipe, ref. D05; a movement which shows how the two components intend to incline towards each other during the joining phase.
The lower seal junction is screwed onto the lower mould pipe, ref. D04, which is then coupled with the upper flanged seal junction during the joining phase. This seal, ref. D04, is made just like the external component, which can be easily disassembled by unscrewing and changed as need be, without needing to substitute the whole valve group.
Although it is not shown in the design, the stems/shutters (ref.Dl l) are po- wered by two hydraulic cylinders situated above the junction unit, ref. D08, and under the appendix, ref. DOl. The stems and shutters are put in symmetrically and once the valve is joined, guarantee the contact between the shutters themselves, moving together. Once separation takes place, the two shutters disconnect, in that one stays attached to the upper valve group and in turn closes the flow of melt into component circuit 01, ref. D09, while the other stays attached to the lower valve group and closes the flow into component circuit 02, ref. D04.
Below is a description of how the oscillating disjunction valve works in relation to the whole moulding machine, through the various mould cycles.
I. The mould mover with one angular rotation can move the mould one place to the front of the press, ready to be inserted.
II. The hydraulic movement system pushed the mould into the press, into its correct central position.
III. The high pressure hydraulic system that is installed in the lower portal of the press lifts the mould from its position and pushes it against the upper portal of the press, until it is forcefully closed shut at maximum 1500 tones.
Simultaneously, during the vertical translation of the mould, the inferior valve group (attached to one another), rises towards the upper valve group, which is attached to the press and connected to the accumulator cylinder head; during the closing shut of the mould against the upper portal of the press, the two valve groups are joined, and the elements (ref. D04 and D09) come in contact with each other, creating a mechanical seal, position Dl.
IV. The hydraulic cylinder which powers the stem and shutter of the lower valve group pushes the lower shutter upward, while the hydraulic cylinder of the upper valve group allows the shutter to push upwards, keeping contact between both shutters, position D02. This way both circuits communicate between each other.
V. The nozzles of the injection system which is fixed to the mould are opened (not visible in the tables).
VI. The accumulator cylinder head can inject the melt into the mould, until it is conserved and full.
VII. The injectors are closed.
VIII. The two shutters form circuits 1 and 2 return to position 02 of table D02, dividing the circuits once again.
IX. The two high pressure cylinders of the lower portal of the press are put into load/change phase, and the moving level along with the mould, drop, causing the simultaneous separation of the lower valve group from the upper valve group, position 03, table D02.
X. The radial hydraulic movement pushed the injected mould into the ro- tating position, freeing up the injection station at the press.
XI. The mould moving wheel makes an angulated rotation from one position, and moves a new mould into an injecting position, whilst the cooling station kicks in at the opening of the newly injected mould; the cycle them re- begins at point I.
Injection system t at least one mould description
This injection system that we are illustrating represents an innovative way in plastic moulding, and multi-moulding. This technology allows us to simultaneously mould various products using to opposing moulds, whilst using a single hot runner system to power both the injection systems. All of which is extremely advantageous when paired with the aforementioned carousel rotating machine.
- Brief description of the injection system designs
This system is visible in table's N°G01 e N°G02, in particular:
• Table G01 shows the welded hot runner system figure A, e B, made up of two stainless steel shaped plates and the welding between each to form a single unit with the power containers. In the same table we can see the completed hot runner system designs C, D, E, where the 2 containers are welded to it.
• Table G02 shows the same hot runner with the assembled noz- zles (N.G34) designs F e G, the lower valve group of the disjunction valve
(two for each mould), an overview of the mould (the upper semi-moulds of the upper and lower moulds are not visible), with the hot runners single powering unit and the nozzles, section C.
• Table G03 shows the injection system mounted onto the moulds, design I, section from itself (D-D), a detail of this section (L), which show the upper and lower nozzles in opposing positions; design M, which shows the lower mould, the injection system and mechanical spacers without the upper mould; design of section E which shows the container at the entrance of the hot runner.
-Detailed description of a shape made by the connection/disconnection device.
In particular, the references in the two tables indicate:
Gl . Lower semi hot runner
G2. Upper semi hot runner
G3. Hot runners power container
G4. Power supply hole in the hot runner
G5. Passageways for the central mechanical spacers
G6. Threaded hole for the rod guide from the stem of the nozzle Ref.G19
G7. 41 mm diameter hole in order to the nozzle core
G8. 4 holes to fix mechanical cylinder spacers from the hot runner and the micro-hydraulic cylinder that powers the opening/closing of the nozzles
G9. 4 holes to fix the 4 locking pins of the nozzles, fitted in case the bayonet system is not used.
G10. The mounting feet of the hot runner (guide) which allows a degree of freedom along the long axis (translation from expansion), and are guided by a core cable (skate) fixed to the degassing plate of the lower mould, ref. 16.
Gi l. Fixed mounting feet of the hot runner at the lower mould. G12. The hot runner system
G13. The 'de-spruing' nozzles
G14. Lower disjunction valve group
G15. Disjunction valve group connection
G16. Degassing plate on lower mould
G17. Degassing plate on upper mould
G18. Mechanical spacer on the external part of moulds
G19. Mechanical spacer on the central part of moulds
G20. Parimetral chamfer to be filled during welding
G21. Nozzle stem guide
G22. Jaws clamping the nozzle to the hot runner
G23. Hydraulic cylinder that controls the nozzle shutter.
In plastic mould injection, more importance is given to production levels and the capacity of the machine, so that cycle times and raw material costs can be re- duced.
In this type of rotating machine, the 3 to 9 stations are worked alternatively, from the cooling process of the products in the moulds to the injection of the empty moulds. Should all the moulds on the carousel be the same shape/size, so that a single type of product is produced, this type of invention doesn't seem logical, nor would an injection system with an "oscillating disjunction valve". This is because the nozzle type used in a "nozzle with a disjunction valve" that is inserted into single in injection system that is fixed to the upper portal of a press already has all of the necessary requisites to obtain low costs and high production levels.
This is different should there be necessary to produce various shape/sizes of products with just one machine. In this case, in order to take full advantage of the machine, it is necessary to use an injection system that is incorporated into the mould, with an oscillating disjunction valve, freeing it from the limitations imposed by fixed geometry injection.
Not only does this system of incorporating the injection in the mould eliminate the problem of creating different products, hence with different injection points, but it also resolves the problem of weight differences in the product in injection moulding.
This practical example of a rotating machine with 6 moulds and 6 stations with one injection system may help. The moulds may have the following characteristics: 1. 32 Kg Fruit/vegetable container.
2. 32 Kg Fruit/vegetable container.
3. 32 Kg Fruit/vegetable container.
4. 32 Kg Fruit/vegetable container.
5. 14 Kg Pallet with crossbars.
6. 14 Kg Pallet with crossbars.
Here we can the difference between the two distinct types of products, with 4x32 kg moulds, and 2x14kg moulds needed.
Without a group description, the accumulator cylinder head will need to inject 4x32 kg and 2x14kg; these conditions will only create poor production levels, as the cooling times needed for the heavier 32kg moulds will determine the length of time and duration of all the moulds in all the stations, which is already fixed and constant, despite the fact that there are lighter moulds on machine.
For example; even if the 14kg pallet takes half the time to inject of the heavier 32kg mould, and in turn the cooling time should also be inferior, it will actually sit in the station under the press and in the cooling station for the same length of time as the fruit/veg container.
This waste in performance is even more evident this way.
The invention, most notably the method used in using two opposing moulds, symmetrical to the injection system, is there to eliminate this waste in performance, by taking advantages of the machine in full.
Rather than injecting pallet singly in each injection station, this way it is possible to simultaneously inject 2 identical moulds, therefore 14kgx2 against the 32kg container.
The geometries of the hot runner system using this method are also quite particular, so that the number of injections in the upper part is the same as the lower.
The opposing double injection system is carried out using a single unit hot runner container, made from two stainless steel plates that are welded together.
These plates that are visible in sections A- A of table Gl are worked on internally, in order to create a flow for the melt. By using two welded pieces means that the passageway can be built specifically, where the flow may be reduced as they pass through the holes of the hot runner, ref. G4, and the holes that are made for the ends of the nozzle cores, ref .G7 (table Gl G3). By being able to work the internal surfaces of the hot chamber being it is welded, it is possible to obtain excellent finishes in the internal walls and create specific radiuses, something that is not normally obtained, all in order to reduce the loss of load during injection.
The final assembly of the hot runner occurs when it is welded, along all the external chamfers, ref. G20 table Gl, all the opened central chamfers (ref. G5) where the central mechanical spacers are, and patch weldering in the internal areas (more specifically where passage holes are created in one of the two ends of the hot runner, that are then welded so that lifting is avoided in the in the central areas, ref. G21).
Once the welding in all the components of the hot runner is finished, the power containers can be assembled.
These containers, ref. G3, are made from two sheets that welded together in a C shape. This shape helps it "wrap-around" the hot runner at one side and it can power the double hot runner in a balanced way.
As seen in design section C, table Gl, the end of the container finishes at the centre of the hot runner at it powers it through the holes, ref. G4.
These holes are present on the core, ref Gl and ref. G2, so that the material can enter form above and below in a balanced fashion, and therefore reducing loss in load and maintaining balanced geometric of power for the nozzles.
These containers practically become "closed' from the hot runner, which squeezes in the centre (section B design C), and to avoid frontal impact from the material, which produces high loss of energy, the side of the container has a double insert, ref. G22 table Gl.
Two central fixed mounting feet are welded onto the hot runner, ref Gl 1, and the others at the longer end, ref.Gl 0.
While the central ones have holes to bolt the hot runner to the mechanical spacers, once fixed to the degassing plate of the lower mould, ref G16, the feet at the end (ref G10), are there to hold the hot runner centrally but allow for thermal expansion caused during the heating phase. .
Being fixed only in the middle and with very little support, it's easy to believe that the expansion in the centre of the hot runner is almost negligible, and while the bolt induces no stress, the feet at the end works as a guide, from to translate on a skater system on the degassing plate, ref G 16. . Once this welding phase is over, everything is thermically tested for expansion in order to geometrically stabilize the piece and reduce any stress caused during the welding, and the machine is further refined.
The hot runner becomes on with the containers which is applied to the nozzles, ref G13 section C table G2, which will both power the upper and lower moulds.
Each nozzle, made up of a nozzle core and a hydraulic cylinder that moves, is then inserted into the inserts in the hot chamber.
This double geometric characteristic, shows power holes for the nozzles on both sides (17+17), making a total of 34 nozzles in the hot runner shown in the de- sign.
The number and positioning of the nozzles is not defined. As there may be different weights and measurements in the product designed, the number and positioning of the nozzles may change, tables Gl, G2 and G3.
The nozzles are inserted from the tail piece seals to the holes in the hot runner, ref G7 table Gl and G3, made within a diameter tolerance coupled with little interference in a way to guarantee to perfectly hold the melt.
In correspondence with the same hole in ref. G7, a series of 4 holes at 90° are created, ref. G9, enabling the jaw shut the bolts, ref G22, which hold the nozzles in position.
On the opposite side of the hot runner, in axis of the hole, ref G7, and of the nozzle core, ref. G13, a hole is present; ref G6, where the guide of the stem of the nozzle is screwed, and a series of 4 holes, ref. G8 bolt the hydraulic cylinder which moves, to the nozzle shutter.
This cylinder, ref. G23 is a squared section and fixed to the hot runner with the help of 4 mechanical cylinder spacers which break up the thermal flow from the hot runner to the core of the cylinder itself, in order to control the temperature of the oil in the hydraulic circuit.
This hydraulic circuit also works as a mechanical spacer between the hot runner and the two degassing plates of the moulds, ref. G16 and G17, stopping the hot runner from raising in correspondence with the nozzles, caused by the effect of pressure in the cavity of the moulds during injection.
Once assembled, the hot runner with all the nozzles is made up of a complete injection system, design F and G table G2, and placed between the moulds and the mounted mechanical spacers, at the end of the hydraulic cylinder, which is in direct contact with the two degassing plates, ref. G16 and G17. This stops the hot runner from vertically translating.
Considering the fact that the injections are extremely intense and the because the hot runner is made from a fairly modest superficial stainless steel, a mechanical spacer plate which distributes a compression force over a higher capability, is put in between the mechanical spacers of the hydraulic cylinder and the hot runner. This way we can avoid deformation on the surface of the hot runner, corresponding with the fastening of the mechanical spacers in the holes, ref G8.
At the ends of the containers, ref. 3 table 1, the disjunction valve groups are fastened, ref. 14 and 15, shown in table 2.
The intension is to show that what are illustrated are only forms of implementation, which is not limited in the invention. An invention which may vary in form and disposition, but never leaves its base concept. Any references in the attached claims are there to facilitate the above descriptions, and any other design attach- ments, and in no way, limits the protection thereof.