PUMPING UNIT FOR THE FILLING OF CONTAINERS IN PACKAGING MACHINES

Abstract: A pumping unit for the filling of containers in packaging machines, in particular of foodstuffs with fluid behavour with the presence of suspended particles, which allows a reliable operating under aseptic condi­ tions, and results easily cleanable. The conical shutter (18) of the pumping unit, selectively connecting the pumping pis­ ton (16) to the product intake duct (23) and to the product deliv­ ery duct (24) is movable backwards from its seat (17), so as to allow an easy and reliable cleaning of unit's body, with no danger of product deposit with consequent loss of aseptic conditions.

Description: The present invention relates to a pumping unit for the filling of containers in packaging machines, in par­ ticular of products with fluid behaviour under aseptic conditions. In the packaging of products with fluid behaviour, in particular more or less hard pasticles of a certain size in suspension in a liquid, inside packaging con­ tainers of the disposable type, aseptic automatic pack­ aging machines are used, which are connected by means of a pipe to units for the processing and the conveyance of the contents to the machine. To secure that to the pack­ aging machine a uniform and predetermined volume per time unit of products to be packaged flows into the individual container being formed from a tube of packaging material, usually a pumping unit is provided, e.g., a metering pump, which at each cycle distributes the desired and predetermined amount of contents. The hygienic require­ ments imposed to such a pumping unit are very severe, as the packaging machine is of the aseptic type, i.e., it produces packages which must be filled with contents which has previously undergone a processing to make it sterile. That is still more desired, in that the particles contained inside the product can be portions of vegeta­ bles, fish, meat and other solid or semi-solid foodstuffs particularly dangerous if they are not stored under con­ ditions of absolute sterility. Known pumping units caused many problems for the packaging machine, in that the complete cleaning thereof inside the packaging plant resulted difficult, and they were hence the staring point for the diffusion of not aseptic conditions. Their particular structure created on one hand an obstacle to the centralized washing of the packaging machine, and on the other was the starting point for infiltrations from the outside, by being not provided with sufficient aseptic barriers, or showing portions which during the operation process could come into connection, even if minimum, with the not aseptic outer environment. Moreover, the particular masses of the pumping body or piston absorbed heat, e.g., during the step of steri­ lization and washing with superheated steam, which they had a certain difficult to lose before the restarting of the production and filling cycle. Not least problem was that of a quite obliged posi­ tioning thereof relatively to the packaging unit of the packaging machine, with some consequent unbalancing or lack in tigthness in the subsequent production step due to vibrations, sudden temperature changes, wear of compo­ nents, with serious difficulties both as for the restora­ tion of the exact matching contacts between the surfaces, and as for the necessary clearances. Purpose of the present invention is mainly to pro­ vide a pumping unit, in particular for the treatment of product with fluid behaviour, solving the whole series of the hereinabove exposed operation and maintenance and adjustment problems, thus allowing a perfectly aseptic production cycle, and an always constant cyclic feed of the product. These purposes according to the present invention are achieved by providing a pumping unit for the filling of containers generated in packaging machines, positioned to intercept a feed duct and a duct for the delivery of the product to be packaged which is of the type with fluid behaviour, essentially comprising a hollow pump body individuating inside its interior a chamber composed by a first cylinderacting portion, containing a sliding pumping piston, and by a conical portion, inside which a hollow conical shutter is rotatably contained, suitable to selectively connect said feed and delivery ducts posi­ tioned in correspondence of said conical portion with said first cylinder-like section, characterized in that said conical shutter is additionally axially translatable relatively to said conical portion, so as to connect both said feed and delivery ducts and said conical portion of said hollow body, a means driving said translational motion being provided. The structural and functional characteristics and the advantages of a pumping unit according to the present invention shall be better understood from the following exemplifying disclosure referred to the related schematic drawings, wherein: Fig. 1 is a cutaway view of a pumping unit according to the invention in operative stage, and Fig. 2 is a cutaway view equivalent to that of fig. 1, in washing stage. Referring to the figures, in a machine (not shown) for the packaging of products with fluid behaviour, in particular composed by particles in suspension inside a liquid, a feed duct 11 supplies the product to a pumping unit according to the invention and indicated with 12, which delivers it into a delivery duct 13, which enters inside a tube of packaging material (not shown), from which in a known way the individual filled package is being manufactured. Of course, all this feeding and packaging operation is carried out under aseptic conditions, to preserve the integrity and the good quality of the foodstuff, and to guarantee the said characteristics with time. The pumping unit according to the invention is in the Example shown a single-cylinder reciprocating meter­ ing pump comprising an outer body 14 inside which a chamber is provided, essentially composed by a first cylinder-like hollow portion 15, suitable to receive a pumping piston 16, connected to a hollow conical central portion 17, extending from said first cylinder-like por­ tion 15. Said hollow conical portion or seat 17 receives a conical shutter 18, within which a front chamber 19 is recessed, provided with a first axial bore 20, suitable to communicate with the cylinder-like portion 15, and with two radial bores 21 and 22 shifted 90° from each other, and selectively connectable by rotation to a feed inlet 23 and to a delivery outlet 24 provided and radial­ ly open outwards on the body 14. The feed inlet 23 and the delivery outlet 24 are connected to the related intake duct 11 and delivery duct 13 by means of pairs of flanges 25 provided with an annular male-female coupling 26, fed by aseptic steam in 27 and positioned between concentric outer and inner annular seats 28, wherein related sealing rings are placed. The conical shutter 18 extends rearwards and axially into a cylindrical portion 30 sliding inside a second hollow cylindical portion 29 of the outer body 14, said portion 30 being in its turn hollow and containing the stem 31 of a piston 32 solidly fastened to it. The other end of the stem 31 is supported inside a sleeve 33 ex­ tending from piston 32 through orientatable thrust bear­ ings 39 and said sleeve 33 is provided with a recessed annular seat 34 acting as stop shoulder against the basis of a ring nut 35. Said ring nut 35, externally threaded, can be screwed down and adjusted in axial position rela­ tively to the stem 31 on a sleeve 36 provided with an inner complementary thread, and fastended on to an outer cylinder 37 within which the piston 32 can slide by means of air fed to the rear chamber 38. A bottom 54 closes the cylinder 37 at the other end and is provided with sealing gaskets 55. The piston 32, the cylinder 37 and the sleeve 36 define a chamber 52 which is fed with air through a bore 56 to actuate the return of piston 32 from its natural operative position and the disconnection of the conical shutter 18 from the conical seat 17. In view thereof, sealing gaskets 53 positioned in­ side the ring nut 35 and acting on the sleeve 33 are provided. A means is thus provided to actuate the translation of said shutter, in the specific case a double-effect cylinder, which is provided with piston stroke adjusting means. The ring nut 35 can be locked in the proper selected position by means of a screw 40 radial relatively to the cylinder 37. The end of the cylindrical portion 30 of the conical shutter 18 receives moreover a lever 41 driving the rotation of the same conical shutter 18 between the two functional positions of connection of the cylinder 15 with the feed inlet 23 and the delivery outlet 24 by means of the radial bores 21 and 22, open one at a time, and by means of the axial bore 20. Externally on the cylindrical portion 30 and on the piston 16, in a zone provided beyond and inside sealing gaskets 42, an aseptic sterile barrier is created by introducing and circulating inside respective annular chambers 43 and 44, e.g., sterile steam or condensate, through respective inlet ducts 45 and 46 and outlet ducts 47 and 48. Around the first hollow cylindrical portion 15 of the outer body 14 a cylindrical jacket 49 is installed, provided with inlet duct 50 and outlet duct 51, inside which jacket a controlled-temperature fluid or liquid is circulated, so as to determine the quick cooling or heating of the big mass constituting the pumping piston 16. As it can be observed and better understood from the figures, both the pumping piston 16 inside the first hollow cylindrical portion 15 and the cylindrical por­ tion 30 of the conical shutter 18 inside the second hollow cylindrical portion 10 of the body 14, show a certain clearance which guarantees,besides a safe posi­ tioning and sliding, also an extreme cleaning easiness. The diameter of the first hollow cylindrical portion 15 lower than the lower diameter of the hollow conical portion 17 allows eliminating any deposits of product, besides allowing a safe washing when the conical shutter 18 is in its rearwards position (fig. 2) because of the inlet of sterile steam or condensate under high pressure. In fact,a pumping unit or metering pump 12 accord­ ing to the invention, once installed between the intake duct 11 and the delivery duct 13, positioned as in fig. 1, receives the product through the feed inlet 23. The product passes then into the radial bore 21 and through the axial bore 20 it goes to fill the first hollow cylin­ drical portion 15, the piston 16 being in its backwards position. The radial bore 22 is closed in this stage against the wall of the hollow conical portion 17. Through the lever 41 only the rotation of the conical shutter 18 is determined, so as to shut the feed inlet 23 by moving the radial bore 22 in corrispondence of the delivery outlet 24. The pumping piston 16 advances so as to push and feed the product to the container, not shown. The pre­ vious cycle of again feeding the product to the pumping unit, and from there to the container over the whole production cycle is repeated. If during the production cycle a loss whatsoever of the aseptic conditions occurs, or if the production is at its end, the whole packaging equipment must be washed and made sterile again. To that purpose, after having stopped the flowof the product, air is introduced through the bore 56. The thrust of the air present in the chamber 52 causes the piston 32 and consequently the conical shutter 18 solid with it to move backwards. This causes the feed duct 11 and the delivery duct 13, the conical portion 17 of the chamber 19 and the first cylindical portion 15 to come into communication, so that all concerned portions are completely washed and sterilized. Then, washing liquid and/or subsequently high-pres­ sure sterilization steam or condensate is introduced. To guarantee that occurrence, according to the invention both the outer pump body 14 and the conical shutter 18 have been made as monolithic pieces without interstices or joints in the mutual facing portions comprise between the intake inlet 23 and the delivery outlet 24 and the annular chambers 43 and 44 embodying the aseptic bar­ riers. Once that the pumping unit has been washed, and that its aseptic conditions have been restored, by supplying air into the chamber 38 the conical shutter 18 is posi­ tioned again against the stop shoulder in its complemen­ tary seat 17. Intervening to adjust the said stroke and not damage or recalibrate the conical coupling is possible, by re­ moving the lock screw 40 and acting on the ring nut 35, so as to displace the position of stop and end of stroke of piston 32, or, better of the annular seat 34 of sleeve 33. After having obtained the desired adjustment, the ring nut 32 is locked again by means of the screw 40. In view of that, it is useful that the interacting threads of ring nut 35 and of sleeve 36 be of the fine pitch type, so as to allow micrometric adjustments. Both in the adjustment step and in the step of positioning of the conical shutter 18 in its seat 17, the presence results moreover particularly useful of the orientatable thrust bearing 39, together with the cou­ pling clearance between the second cylindrical portion 29 of the pump body 14 and the cylindrical portion 30 of the conical shutter 18. In fact, a self-centering of the shutter is so allowed, even if precise and congruent tolerances between the components, or better between their portions which come sequentially into contact do not exist. Advantageously, according to a preferred embodiment of the present invention, the inclination angle of the conical coupling shall be around 20°, and the material constituting the conical shutter 18 shall be a ceramic material, with the drive stem 31 of steel having a heli­ cal outline, for a better mutal constraint with the ceramic material obtained, e.g., by means of resin such as araldite, allowing an essentially flexible coupling, and a better sealing between the surfaces in mutual engagement.

Claims: 1. Pumping unit for the filling of containers gene­ rated in packaging machines, positioned to intercept a feed duct (11) and a duct for the delivery (13) of the product to be packaged which is of the type with fluid behaviour, essentially comprising a hollow pump body individuatig inside its interior a chamber composed by a first cylinder-like portion (15), containing a sliding pumping piston (16), and by a conical portion (17), inside which a conical hollow shutter (18) is rotatably contained, suitable to selectively connect said feed (11) and delivery (13) ducts positioned in correspondence of said conical portion (17) with said first cyliner-­ like portion (15), characterized in that said conical shutter (18) is additionally axially translatable relati­ vely to said conical portion (17), so as to connect both said feed (11) and delivery (13) ducts and said conical portion (17) of said hollow body (14), a measns (32, 37) driving said translational motion being provided. 2. Pumping unit according to claim 1 characterized in that said conical shutter (18) extends rearwards in a cylindrical portion (30), to which said drive means (32, 37) is constrained, sliding inside a second cylindrical portion (29) of said pump body (14), aseptic sealing chambers (43, 44) being provided between said first cy­ lindrical portion (15) of said body, and said piston (16) and between said second cylindrical portion (29) of said body and said cylindrical portion (30) of said conical shutter. 3. Pumping unit according to claim 1 characterized in that said drive means (32, 37) is a double-effect cylinder (37), solid with said pump body (14), comprising a piston (32) bearing a stem (31) constrained to said conical shutter (18), said cylinder (37) being provided with means (35, 40) for the adjustment of the stroke of said piston (32). 4. Pumping unit according to claim 1 characterized in that externally to said first cylinder-like portion (15) a jacket (49) is provided, into which a controlled-­ temperature fluid is fed. 5. Pumping unit according to claim 1 characterized in that it is connected to said ducts for product feed (11) and product delivery (13) by means of flanges (25) provided with aseptic seal chambers. 6. Pumping unit according to claim 2 characterized in that said first cylindrical portion (15), said conical portion (17) and said second cylindrical portion (29) of said pump body (14) are obtained in one single piece. 7. Pumping unit according to claim 2 characterized in that said conical shutter (18) and said rear cylindrical portion (30) are obtained from one single piece. 8. Pumping unit according to claim 1, characterized in that said conical shutter 18 is self-centering relati­ vely to said conical portion (17) and that said conical shutter (18) is connected to said drive means (32, 37) with the interposition of orientatable end elastic means (39). 9. Pumping unit according to claim 1 characterized in that the lower diameter of said conical portion (17) is not shorter than the diameter of said first cylindri­ cal portion (15). 10. Pumping unit according to claim 1 characterized in that said conical shutter (18) is of ceramic material, and is connected to said drive means (32, 37) by means of a flexible coupling.

Inventors: BORDINI, GIORGIO
Applicants: TETRA DEV-CO
Application year: 1986
Main classification: B67C3
IPC codes: F04B53, F04B15, B67C3, A23L3, B65B3