FIELD OF THE INVENTION

The present invention relates to a head device for metering and statically mixing resin, paste and filler or stucco products, in particular based on epoxydic material, including two or three components having short and average pot-life properties, filled-in with high specific weight abrasive powders such as quartz, zirconium, glass, silica or the like, said filler and paste materials having the following extreme or end physical properties:

Viscosity (Values detected according to the CONE PENETRATION test)

Cone penetrometre sample 25 ⁰ C 15 sec, penetration = 13 ram.

BACKGROUND OF THE INVENTION

As is known, prior systems for metering and mixing highly abrasive products conventionally comprise operating heads including valves, valve gaskets and combined gasket arrangements, which are quickly subjected to wear because of the abrading operation. Said head arrangement require frequent and expensive maintenance and cleaning operations, in particular for metering and mixing abrasive product holding products, which maintenance and cleaning operations also require replacements of said head, repairing thereof with frequent stops of the systems and a consequent loss of

the production yield together with very high maintenance costs.

SUMMARY OF THE INVENTION

Thus, the main object of the present invention is to overcome the above mentioned problems, by- providing a head device for mixing and metering materials, highly abrasive products included, which does not comprise valves and dynamic gaskets on its pistons, thereby drastically reducing the maintenance requirements thereof, with a consequent very short dead time of the system, i.e. a dead or idle time near to zero. A further object of the invention is to provide a head device of flexible size and flow-rate, which head device can be specifically fitted to system production requirements, with very small constructional modifications .

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment and an application of the invention will be disclosed in a more detailed manner hereinafter, with reference to an use thereof related to the most significative market requirements, without limiting the invention to said embodiment and application. In particular, the above and further objects and advantages of the invention will become more apparent from the following detailed disclosure of the invention, together with the accompanying drawings, where :

Figure A shows the mixing and metering head device according to the present invention, in a fully assembled condition.

Figure B is a cross-longitudinal section view illustrating all the main components of the inventive device such as: the metal rotor, ceramics pistons, ceramics liners, fixed ceramics disc, gear wheel and pinion for angularly turning the ceramics rotor with respect to the fixed ceramics disc, the actuator and miniaturized built-in electronics therefor, the gear reducer unit with its built-in miniaturized electronics for angularly turning the metal rotor, and the static mixer.

Figure C is a cross sectional view illustrating: the ceramics rotor, fixed ceramics disc, articulated joints of the ceramics pistons, and metal and bottom metal bodies of the device.

Figure D clearly shows: a tie-rod assembly for fully assembling the head device, quick clamping devices for pressurized cartridges holding therein the components of the product to be delivered, and the static mixer.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a metering and mixing head device comprising: a body to which the following components are coupled: a facing ceramics disc switch or commutator assembly, said facing ceramics discs comprising a fixed ceramics disc and a 22°30' or 45° or 90° or 180° rotary

ceramics disc.

The pistons sliding through the liners of the main body have a piston diameter/cylinder length ratio

(with the exclusion of the operating stroke) from 1 to 5 mm, and up to a value from 1 to 15 mm, and cause a load loss providing a Delta P eliminating blow-by losses of the components of the product to be delivered or metered.

As is clearly shown in figures A-B-C-D, all the operating gaskets and valves originating the above mentioned problems and which have been overcome by the invention, have been eliminated.

Moreover, the present invention also provides metering and mixing devices for metering and mixing low and very low density products, with fixed mixing ratios. In such an application, for drastically reducing cost, linear and rotary pneumatic actuators, instead of the motronic actuators are used.

Moreover, for high viscosity products, the invention provides to use: electromechanic actuators with brushless motors, encoders, coaxial epicycloidal gear units, in addition to a converter device for converting the rotary motion to a linear motion (ball recirculating screw and bush) ; in addition to the possibility of providing a PLC-PC interface. The above disclosed actuator provides a constant and high mechanical torque. The provision of an advanced miniaturized electronics unit allows the desired process to be easily driven and programmed; this in turn allows to construct the subject head device with a very small size, to greatly increase its possible application range.

Moreover, if two or three component products must be mixed with different mixing ratios, it would be sufficient to replace the rotor and related piston and fixed ceramic disc kit with another kit including pistons and piston liners having diameters fitted to the novel desired mixing ratio.

Such an approach allows to use a single actuator, and fully eliminate any electronics arrangements, with a consequent great advantage from a cost standpoint.

Moreover, the present invention provides a mixing and metering head device for mixing and metering product components the operation thereof is based on the following operating steps: axial movement: by the actuator 49 for drawing or sucking the product components by causing the pistons to axially slide in their piston liners, to send said components, under pressure, to the static mixer; rotary movement: by the gear reducing unit 050,

047 (or motronic assembly, Fig. A, in an embodiment of the invention) , to cause the metal rotor to turn and, accordingly, to consequently cause the ceramics rotor to also turn for cutting product plugs and switching the product component flow from the suction to the delivery ducts.

The above mentioned axial and rotary movements allow to carry out the following processing or operating cycle: - "I" - drawing or sucking the components forming the product to be delivered (see figure D)

- "II" - turning the movable ceramics rotor with

respect to the fixed ceramics disc.

- "Ill" - delivering the basic component and second component forming the product to be delivered toward the static mixer (see Fig. B) - "IV" - reverse turning, with respect to the item "II", and repeating and restarting the operating cycle of the preceding items.

To provide the operating cycle of the above items I-II-III-IV, it is necessary to reciprocatedly or alternatively turn the ceramics rotor, firstly in a clockwise direction and then in an anticlockwise direction.

The above mentioned gear reducing unit 49, coupled to a pinion and a gear wheel, is programmed to provide the angular movements required by the subject process .

During a rotation of the ceramics rotor through

90° (17 in Fig. B) (for the two-component head device), or through 45° (for the three or four component head device) , the facing delivering holes and, accordingly, in an angular phase with the fixed ceramics disc (16 in

Fig. B), actually cut-through the supplied flow of the products to be metered and mixed. Finally, the lowering metering piston operation sends to the outlet of the head device, or to the static mixer, the required product, thereby completing the process, and providing a product suitable for the intended application.

The two components of the metered products, held at a temperature of 5O ⁰ C, and affected by the urging pistons sliding in the cylinders with a force of about

60 Kg, follow their displacements toward the static mixer, to become a single mixed and homogeneous

component, which is ready for starting the curing or cross-linking process.

The temperature of the product, which is held at a constant value, helps in assuring a volumetric or weight supply repeatability, in addition to reducing the viscosity of the product to allow said product to be handled in a more easy manner.

The constructional principle of the head device according to the present invention comprises the following components:

- ceramics pistons and cylinders for metering the components;

- a ceramics rotor and a fixed ceramics disc; as the ceramic rotors turns with respect to the fixed ceramics disc, it switches the components from the sucking or drawing duct to the delivery duct; hydraulic sealing between the cylinder and piston, obtained according to the high load loss principle; - a digital motronic assembly for linearly operating the pistons;

- a digital motronic assembly for turning or rotating the ceramics rotor.

The desired metering of the mixed product to be delivered is provided by the head device according to the present invention by the following operating or processing steps:

"1") - A digital weighting or volumetric prearrangement of the product to be metered (in paste, liquid or powder form) . The delivery of the product can be preset for an alternating or continuous flow mode of operation.

"2") - Sucking or drawing of the product components from commercial vessels or pressurized product cartridges which are temperature controlled up to 60 ⁰ C for paste and filler materials. "3") - A turning or rotary movement of the ceramics rotor with respect to the fixed ceramics disc to cause the two component fixed ceramics disc outlet holes to be lined-up, thereby causing the product plugs, metered during the sucking step, to be cut- through. The two facing discs (i.e. the ceramics rotor disc and the fixed ceramics disc) , during their angular operating step, cause the metering pistons to be lowered to supply or deliver a desired volume or weight of the two product components. "4") - A delivering of the two sucked or drawn products according to the pre-arrangement of item "1".

"5") - A reversing rotating of the ceramics rotor with respect to item "3".

Repetition of the cycle as disclosed at the above items "2"-"3"-"4"-"5" .

DISCLOSURE OF A FURTHER PREFERRED EMBODIMENT

The "top head body" comprises a projecting portion for handling, and/or clamping the head device to its intended apparatus. Accordingly, the top head body must be considered as a fixed component.

It comprises front projecting portions, of trapezium configuration, adapted to be coupled, without any angular clearance, to the bottom head body also comprising front trapezoidal recesses.

A plurality of small bottom slots being moreover

provided for releasing possible overpressures, due to the coupling of the trapezoidal projecting portions with the bottom head body.

Figures A, B, C, D shows recesses or seats for housing therein the bush and fifth wheel assembly for driving and turning the metal and ceramics rotor.

The top portion of the head device, i.e. the "top head body" comprises a suitable seat for housing therein the safety metal cap protective assembly. The top head body comprises two side contact surfaces for applying two PTC devices (see 51 in Fig. B) for providing an always constant temperature of the head device (the normal operating temperature being of 50 ⁰ C +/- 1°C) . With the above constant temperature, the viscosity of the resin or filler material will also be constant through the overall process operating time. (As is known, resins are products which, in a lot of cases, reduce, even in an exponential manner, their viscosity under a temperature increase of 20-30 ⁰ C).

A constant resin temperature will assure a desired repeatability of the curing or polymerizing times, with a consequent repeatability of the delivered resin volumes or weights, even in the presence of temperature variations.

Bottom head body (18)

The bottom head body 18 houses therein the fixed ceramics disc and threaded nipples (20 Fig. D) suitable for delivering the paste, filler or resin components, and comprising moreover a quick clamping device indicated by 25 in Fig. 4, for the static mixer (made

of a stainless steel material AISI 316-304), adapted to resist against high operating pressures (up to 200 newtons) .

Said body also comprises two or three 0-rings made of TEFLON (as indicated by 38 in Fig. 2), for providing a static hydraulic sealing of the holes delivering the component A and component B through the static joints between the pump bottom body and the ceramics disc. The nipples for delivering paste or filler or resin material to the fixed ceramics disc also provide a strong coupling between the bottom head body and the fixed ceramic disc.

The bottom head body comprises four female notches, of trapezium configuration, provided for receiving and operating against the torque generated by the turning movement of the ceramics rotor housed in the top head body and transmitted by the four male projection portions.

Metal rotor (10)

The function of the metal rotor 10 (indicated by 10 in Fig. C), is that of housing therein all the components of the ceramics rotor in addition to the pressing element of said ceramics rotor, thereby allowing said ceramics rotor to be properly supported and turned, and protecting it against anomalous movements and urging forces which could cause the liners to be broken (due to brittleness of the ceramics material and the side urging stresses) .

Ceramics rotor (17)

The ceramics rotor 17 can comprises two, three, four or more ceramics liners therein the pistons are caused to slide.

Said ceramics lines are made rigid with the movable ceramics disc both due to their accurate coupling and because they are glued with a perfect perpendicular relationship with one another (fig. B) .

To provide an inter-exchangeability property, if the product must be delivered with a different mixing or volume ratio, the outer diameter of said liners is always held at a strictly constant value.

For providing unexpensive technical means for volume or weight delivering the desired product, the diameter of the pistons and inner diameter of said liner must correspond to cross-sections of 80- 90 -100-

120-140 mm ² .

The piston diameter and liner length ratio (with the exclusion of the maximum stroke of the pistons) varies from 1:5 to and beyond 1:15. (The liners, for constructional simplicity, can also have a modular construction) .

For pistons having diameters less than 6 mm, the piston diameter/liner length ratio (with the exclusion of the maximum stroke or displacement of the piston) , can achieve a value of 1:5.

For diameters larger than 6 mm, the piston diameter/liner length ratio (with the exclusion of the maximum stroke or displacement of the piston) can exceed a value of 1:15. The ceramic rotor, depending on the number of the components forming said paste or filler material, comprises two or three or four ceramics liner holder

seats or recesses.

Fixed ceramics disc (16)

The fixed ceramics disc 16 is arranged opposite to and facing the movable ceramics rotor.

Said fixed ceramics disc, as is shown in Figures B, C and D is designed as follows: A trapezoidal cross-section

Designed for housing therein the product component delivery nipples, said fixed ceramics disc comprising a plurality of holes radially extending from the disc axis to the product component supplying or delivering ducts.

The fixed ceramics disc also comprises a central throuhgoing hole for allowing a tie rod for connecting the overall metering head device to pass therethrough.

Ceramics rotor pushing or pressing assembly (15-30-32-39)

The function of this component assembly is to provide a constant pressure between the fixed ceramics disc and movable ceramics disc (015-030-032-039 Figs.

1-2-3-4). The applied pressure is proportional to the counter-pressure the paste or filler or resin product is subjected to because of the pressurized supplied material which, from the commercial vessel or pressurized temperature controlled cartridge, is supplied to the metering and mixing head device.

The pressure to be applied to high viscosity paste or filler products, to meet the application characteristics, can also exceed a value of 15 Kg/cm ² .

Said pressure being necessary and required for compensating for the load losses due to the static

mixer .

The top portion of the pressing element-rotor comprises a gear wheel which, engaged with the pinion of the coaxial gear unit, allows it to be turned (see the reference number 09 in Fig. C) .

Articulated joint fixtures for the piston-actuator (35)

These two devices provide an elementary, though very delicate, function, since the sleeve attachment for the ceramics piston is made by glueing. Inevitable offsets must be compensated for by suitable devices. The articulated joint provides a zero axial clearance and, in the meanwhile, compensates for an inevitable offset between the ceramics piston and actuator (35 in Fig. C) .

Tie-rod for fully assembling the head (07)

The tie-rod 07 for assembling the head device is very simple construction wise but very important. A single tie-rod (07, Fig. B) connects and holds rigidly coupled all the components of the head device during the multiple and hard work cycles the head device is subjected to, such as the mechanical tension and torque stress due to friction during the rotary operation for cutting through the product plugs between the fixed ceramics disc and ceramics rotor. Moreover, the thermal (50 ⁰ C) and abrasive action on the head device components, contributes to increasing the applied resistances and, accordingly, the mechanical stress. The two side portions of said tie-rod are threaded, thereby a side of the tie-rod is rigidly threaded to the bottom head body (18, Fig. C) .

The opposite side houses the twist bearing, washer and nut for clamping and integrally disassembling the head device together with the safety counter-nut for preventing them from being unthreaded (28, Fig. A) .

The tie-rod also comprises, if necessary, an axially extending perforation for supplying therethrough a washing solvent for washing the head device . Said tie-rod also comprises a suitable recess for receiving therein the trust bearing (30, Fig. A), which is so sized as to resist against the great axial and torsional load it is subjected to because of the production process operating steps. The metering head device has a lot of advantageous novel features and, more specifically: a. It is free of valves, since they are not suitable to operate in the presence of abrading materials . b. It is free of dynamic sealing gaskets, which are not suitable to provide dynamic sealings. c. It is free of maintenance requirements (for the reasons indicated at items A and B) . d. It can be easily used in the presence of very high density products such as paste and filler or stucco materials and the like. e. It can be easily assembled and disassembled by merely removing the nut of the counter-nut or knob assembly of the tie-rod, thereby rendering the subject head device a very rational and unique construction for a lot of applications, with the further advantage of disassembling, for removing and quickly replacing the

ceramics rotor and ceramics disc with another like component suitable for the desired mixing ratio and reassembling in the apparatus in about two minutes. In the two or more actuator head device embodiment, it comprises a knob element replacing the clamping nut, thereby an integral assembling and disassembling of the head device can be carried out by merely using the hands and in a manner quicker than in the preceding case .

Piston driving actuator (49)

As the inventive device may fit a very broad range of commercial applications with a reduced size for metering and mixing high density resin and paste materials, with a great accuracy and repeatability, said metering head device has been designed to comprise a brushless motor, an encoder, a gear unit, and a ball recirculating actuator, adapted to provide an urging force of 600 newtons. Moreover, the assembly also comprises the related miniaturized built-in electronics .

The accompanying drawing shows an use of a single actuator: however, it should be apparent that the number of actuators can be increased to several units, if required by the number of the components of the paste material or of the paste or filler or resin products .

The brushless motor, encoder, epicycloidal- coaxial gear unit, ball recirculating actuator and driver and related built-in electronics assembly provide the required functionality and reliability, with a very reduced size.

The actuator indicated by the reference number 49 is moreover clearly shown in Figs. A-B-C.

The cap safety protecting assembly shown in Fig. 1 can be removed by merely using the hands.

The ceramic rotor rotatively driving gear unit (50-47)

The device or unit for rotatively driving the metal rotor and consequently the ceramics rotor comprises a brushless motor coupled to an epicycloidal coaxial gear unit including its built-in control electronics, and related encoder for controlling the angular rotary movement of said ceramics rotor (see the reference numbers 47-50 of fig. A).

The metering and mixing heads for metering and mixing low viscosity resins and liquids can also comprise a pneumatic actuator for driving the pistons and a pneumatic device for driving the ceramics rotor, thereby drastically reducing cost.

The present invention has been disclosed thereinabove with reference to embodiments thereof which must be considered as merely exemplary and not limitative of the scope of the invention as defined in the accompanying claims.

INDUSTRIAL APPLICABILITY

The present invention can be applied to systems or apparatus for: electromechanic industry: impregnating of electric windings or coils by the trickle, casting or potting or coating or compound incapsulation method, even under vacuum.

A static and dynamic balancing of: armatures, rotors, fans and rotary components.

- Sealed closures for electric cable junctions (even under vacuum) . - In the telephonic industry: sealed closures for telephonic cable junctions (even under vacuum) . In the dental field for baking imprints. In the casting field: for metering and mixing sand, granular and compound materials for arts and industrial castings.

In the professional and amateur model or pattern field.

In the building field: for filling and sealing closures of junctions. - In the food industry: for metering meals, flours, grains, chocolate, jams and confectionery products.

- In the paint industry: for liquid and powder paints (for compounding colors or dyes).

In the ink industry: for compounding products and colors.

- In the pharmaceutically industry: for sterile, inert and/or vacuum atmosphere metering of experimental substances and components.

- In the chemical industry in general: for metering and mixing chemical and lab substances.

- In the search field: in search labs in general and universities .

Legend of the drawings

000 Metering and mixing head assembly 001 Actuator support

002 Actuator support screws

003 Piston driving plate

004 Actuator support spacers

005 Clamps for articulated joints for piston actuator

006 Sleeve clamps for articulated joints

007 Tie-rod for assembling and closing the head

008 Tie-rod protective Teflon liner

009 Gear wheel for turning the ceramics rotor 010 Metal rotor

011 Metal rotor guide bush

012 Metal rotor drive wheel

013 Ceramics piston

014 Ceramics liner 015 Ceramics liner urging spring guide bush

016 Ceramics stator

017 Ceramics rotor

018 Bottom head body

019 Top head body 020 Paste or filler material injection nipple

021 Ceramics rotor top head body rotary pinion

022 Top head body rotary gear unit support

023 Head protection casing

024 Top head body rotary brushless gear unit 025 Head heater PTC from 5O ⁰ C

026 Clamping screw for PTC from 50 ⁰ C

027 Actuator rod clamping nut

028 Head assembling rod clamping nut

029 Paste injection nipple sealing 0-ring

030 fifth wheel bearing

031 Thrust bearing pressing washer 032 Ceramics rotor pressing cup springs

033 Head body rotating gear unit support clamping screw

034 Screw

035 Ceramic rod attachment articulated joint 036 Gear unit pinion guide bearing

037 Pinion clamping seeger

038 Fixed ceramics disc sealing 0-ring

039 Ceramics rotor pressing spring

040 Ceramics rotor pressing bush 041 Gear wheel coupling pin

042 Ceramic liner pressing spring

043 Ceramic liner pressing spring guide bush

044 Ceramics body rotating gear unit clamping screws 045 Actuator clamping nuts

046 Liner-piston-O-ring

047 Ceramics rotor turning epicycloidal gear unit

048 Plate clamping nuts

049 Piston driving actuator 050 Static mixer