EP2490949B1

EP2490949B1 - A nozzle head and a filling machine provided with said nozzle head

Info

Publication number: EP2490949B1
Application number: EP10825276.8A
Authority: EP
Inventors: Lasse Andersen; Stefan Sollerhed
Original assignee: Tetra Laval Holdings and Finance SA
Current assignee: Tetra Laval Holdings and Finance SA
Priority date: 2009-10-23
Filing date: 2010-10-21
Publication date: 2016-08-10
Anticipated expiration: 2030-10-21
Also published as: CN102596729A; EP2490949A4; BR112012009469A2; CN102596729B; WO2011049505A4; EP2490949A1; WO2011049505A1

Description

Technical Field

The present invention relates to a filling assembly, in particular to a filling assembly including a nozzle head suitable for filling liquids prone to foam and splash into packages having a rounded bottom surface. Moreover, the present invention relates to a filling machine including the filling assembly described earlier.

Background

In filling machines where liquids are filled into packages, some sort of nozzle head is used to distribute the liquid into the package. In the filling machines of today the rate in which packages have to be filled is increasingly high. For certain liquids, such as milk and in particular low fat milk, yet also for some fruit juices such as pineapple juice, just to mention a few relevant examples, foaming may then be a problem. Foaming occurs as the injected jet of liquid admixes air into the liquid, which rapidly flows over the rim of the package, resulting in problems in achieving an adequate fill of the package. The general desire is to achieve a high fill rate, enabling a high production rate, and low foam generation, enabling a high fill ratio (optimum use of the interior volume of the package). A related problem is splashing, where the jets of injected liquid impinges on the walls of the package or into the liquid contained in the package, and causes liquid to splash out of the package. Both problems are aggravated by filling rate and distance between nozzle head and package, and they are coupled in that increased foam generation results in decreased splashing, the foam acting as a splash damper absorbing droplets.
The present applicant has revealed that the problems are particularly severe for a certain type of package, namely the so called carton bottle which is comprised of a cylindrical sleeve made of packaging laminate and a plastic top connected to the laminate sleeve at one end thereof. The plastic top comprises a neck either closed by a membrane or a cap covering the pouring opening of the carton bottle, and generally has curved shoulders. A carton bottles is manufactured with an open bottom to enable, inter alia, filling from the bottom when the carton bottle is in an upside-down condition. After filling the bottom of the carton bottles is sealed and formed into the desired shape.
The filling is done in a number of steps wherein a predetermined partial volume of the product to be packed is filled in every step. Especially the first filling step may result in an undesirable amount of product splashing as a result of the filling jets hitting the inside of the membrane or cap closing the neck, if a standard filling nozzle injecting the product straight into the package is used. After the jets hit the membrane or cap they turn upwards maintaining almost the same speed which results in the splashing, and also foaming. This may be compared with a classic package having a right angled shoulder, which is less efficient when it comes to reversing the momentum of the injected liquid, and this is less prone to splashing.
A known solution regarding reduction of foaming and splashing is to direct the flow of injected liquid towards the interior side walls of the package. This is accomplished by using a nozzle head having several nozzle openings guiding the injected liquid towards the walls of the package. In this way the flow may be guided by the walls and enter the liquid already present in the package with a weaker tendency of admixing air into it, and since direct impacts with one end of the container is avoided splashing will also decrease. One such device is disclosed in US-4 711 277 .
The invention is directed towards further improving prior art in relation to filling of a package, for example a carton bottle of the described type.
The problem of the prior art is that because of the valve means the flow of product enters the inlets of the filling nozzles from only one direction. The flow is therefore less well-defined and leads to increased forming and splashing. The present invention provides a solution to this problem and other drawbacks existing in prior art.

Summary

US4375826 discloses another solution with a rotary filling apparatus where containers are travelling on an annular conveyor belt while the filling apparatus comprises filling nozzles arranged on a crank rotatably arranged on a shaft. In order to optimize the filling process the rotational speed of the nozzles on the crank is adapted to match the rotational speed of the container. To prevent splashing and foaming of a product dispensed from the filling nozzles into the containers, the filling nozzle heads are provided with thin elongated channels with through which the product to be filled exits. The flow of the product entering the filling nozzles is controlled by a valve means having a flat valve face movable in and out of engagement of the inlets of the filling nozzles.
The inventive filling assembly is defined in claim 1, and the characterizing features results in the advantages obvious from the detailed description. Preferred embodiments are defined by the dependent claims. A filling machine provided with the filling assembly according to one or more of its embodiments is defined in claim 11.

Brief Description of the Drawings

Fig. 1 is a slightly off-center cross section of a filling assembly including the nozzle head of one embodiment of the present invention.
Fig. 2 is a side view of a nozzle head included in the filling assembly according to one embodiment of the present invention.
Fig. 3 is a top view of the nozzle head of Fig. 2.
Fig. 4 is a sectional view along the line IV-IV of Fig. 3.
Fig. 5 is a sectional view along the line V-V of Fig. 3.
Fig. 6 is a schematic side view of a filling station comprising a filling nozzle according to one embodiment of the present invention.
Fig. 7 is a cross section of a nozzle head included in the filling assembly according to a one embodiment of the present invention.
Fig 8 is a fold out view illustrating a cooling arrangement according to one embodiment of the present invention.

Description of Embodiments

Fig. 1 is a partial cross sectional view of a filling assembly 1 including a nozzle head 2 according to a first embodiment of the present invention. The filling assembly 1 is attached to a dish box 4 to form a filling unit 5 the illustrated assembly is part of a filling station of a filling machine for filling pourable food stuff into packaging containers. The packaging containers have been sterilized prior to filling, and maintenance of aseptic conditions until the packaging containers have been filled is a paramount issue in this context. The filling unit, with its large interior surface area therefore has to be cleaned and sterilized on a regular basis. If the unit is arranged in an aseptic environment, the cleaning and sterilization should preferably be performed without disturbance of the aseptic conditions. Disassembling the unit for cleaning and sterilization would be cumbersome, time consuming and would require a reassembly performed under aseptic conditions, and is therefore not desired. For this reason a dish box 4 is arranged. The dish box 4, a portion of which is shown in Fig. 1, comprises vertical through holes 6, in which the nozzle head 2 may be inserted with a clearance. The through holes 6 may comprise a first portion having a first diameter, followed by a second portion having another diameter, i.e. the opening 12 in the dish box, to be described. The dish box 4 also comprises a horizontal channel 8, interconnecting all vertical through holes 6. Not shown in the drawing are blocking means that may be controlled to seal the openings 12 of the dish box 4 from below. The pourable product have to pass these openings 12 in order to reach the packaging container below, and by sealing off the openings 12 the filling station may be separated from the rest of the filling machine. To facilitate the sealing it is beneficial if the openings 12 are as small as possible. Also, smaller opening 12 enables a smaller distance between adjacent filling assemblies 1, which in turn may enable shorter indexing steps and an increased production rate. Smaller openings 12 further enables less bulky mechanics for the blocking means. After sealing, the filling unit 5 may be cleaned, sterilized by pressurized steam or by other means, flushed etc, without affecting the rest of the filling machine. Returning to the filling assembly 1, and still referring to Fig. 1, it comprises a housing 14 having an inlet 16 for the pourable product. A rod 18 is arranged centrally and controlled by a servomotor to move up and down. The servomotor enables maximal controllability and adjustability, yet other drive means are also possible. A resilient membrane 20 separates the product containing portions of the filling assembly 1 from the rest.
A throttle device 22 is arranged on the rod 18 and cooperates with a bulge 24 of the housing 14 to provide a seal in a closed position. Portions of the circumference of the throttle device 22 are recessed, such that the flow may be controlled with improved accuracy as the throttle device 22 moves towards an open position (upwards). In such an instance channels with increasing diameter may be formed between the throttle device 22 and the bulge 24 before the throttle device 22 is moved enough to loose contact with the bulge 24 completely. At the distal end of the rod 18 a valve cone 26 is arranged. In this embodiment the valve cone 26 comprises a body of stainless steel overmoulded with silicone. The side of the valve cone 26 facing downwards is essentially planar but for a central recess 28. A rim 30 surrounding the recess 28 is arranged to provide a seal towards inlets 32 in the nozzle head 2, via the silicone coating. The central recess 28 is in fluid communication with a volume above the valve cone 26 by means of at least one passage 34. This prevents the occurrence of vacuum as the valve cone 26 is raised, which could affect the controllability. It also enables more surfaces to be cleaned automatically. In order to avoid air from being trapped in the recess 28, which also could affect the metered volume of pourable product and the possibility of sterilizing the device, the passage or passages 34 are preferably located at an uppermost location of the recess 28. One further effect of the passage 34 and the central recess 28 is that as the flow of product enters the inlets 32 from more than one direction. As a result the flow through the channel will be more well-defined, and in that way the passage 34 also assists in reducing foaming and splashing.
This methodology may also be advantageously used for other applications than the present embodiment, or even invention. It may e.g. be utilized in a nozzle assembly having the corresponding or even the same construction as the present invention upstream of the inlets 32. such construction may have more than one set of inlets 32, such that e.g. there are two sets of inlets distributed around the center of the nozzle head at two different radii. In such a situation the above construction will result in that the product may reach the two sets of inlets simultaneously, resulting in a well-defined and even output of fluid from the nozzle head. This may be compared to a situation where the product first need to pass a (radially) outer set of inlets before reaching the (radially) inner set of inlets, resulting in a temporal lag between the output of product, and an uneven flow of the same from the nozzle head. The present invention therefore relates to a filling assembly constructed in accordance with the above description, including such a valve cone combined with a nozzle head having more than one set of inlets. In that respect it may be noted that there may be more than two sets of inlets, and there may be more than one recess and passage, such that e.g. there are three sets of inlets arranged along separate radii, and three sets of recesses and passages enabling fluid communication to the area between the sets of inlets. The recess and the passage may also be formed from essentially the same volume, such that the passage more resembles a continuation of the recess rather than a small diameter bore. The valve cone may e.g. also be designed as a series of interconnected concentric ring structures, interconnected by material bridges. The ring structures are then used to cover the inlets and the recess and the passage will then by defined as the volume between the rings. A person skilled in the art will realize that the shape and position of the "ring" will be defined by the arrangement of the inlets. Generalizing this aspect of the invention even further, it therefore represents a valve cone having an outer perimeter where it is contacting a nozzle head, as is known, the valve cone being characterized in that it allows access, fluid communication, with the nozzle head radially inside of said outer perimeter.
Returning to the present embodiment having only one set of inlets, the nozzle head 2 has several through holes or channels 10 arranged to guide the pourable product from the upper to the lower side of the nozzle head 2. In the illustrated embodiment the through holes 10 are straight channels, yet since the cleaning is performed by injecting a fluid through the through holes they may also have a more complicated shape. Each nozzle outlet 36 is arranged to direct a jet of pourable product towards the wall of a packaging container arranged below the openings 12 of the dish box 4 (see Fig. 3), the constraint being that the jets have to pass through the opening 12 without interaction. For several reasons already mentioned it is desired to keep the diameter of the openings 12 as small as possible. It is crucial that the jets remain separated from each other, since they will divert significantly if not. This in turn results in the jets not passing through the opening 12 without interaction and any jet interaction with the rim of the openings 12 obviously results in significant splashing and jeopardizes the aseptic conditions and decreases controllability of the filling process. The applicant found that if the nozzle outlets were flush with the bottom surface of the nozzle head 2 the jet separation initially was adequate. Over time, however, minute material build-up (comprising pourable product) around the nozzle outlet resulted in diverging jets, instable, flickering jets and increased interaction between neighboring jets and splashing. It also lead to the jets impacting onto the inner wall of the dish box (along the rim or the opening 12), resulting in considerable contamination. The solution to this problem was the arrangement of lips (see at reference number 36) projecting from the bottom of the nozzle head 2 in the direction of each through hole or channel 10. Each lip 36 preferably ends with a sharp rim. The arrangement of the lips 36 reduced the occurrence of diverging jets to the point where this does not limit the operative time between cleaning. It is believed that the sharp rim enhances the beneficial properties of the lip 36, since the risk of material build-up decreases. To assist somewhat in the definition of "sharp" it may be clarified that for the purpose of the present and other embodiments the ratio between the width of the rim and the diameter of the orifice may be in the order of 0.05-0.2, preferably 0.05-0.1. The present applicant does not rule out even lower ratios, yet a thinner rim is generally more difficult to produce and less durable. For an orifice having a diameter of about 8 mm this results in a rim having a width of about 0.4-1.6 mm, preferably 0.4-0.8 mm, which may be relevant dimensions for the orifice of one or more embodiments of the present invention. It should also be mentioned that the use of a nozzle head 2 having a smooth exterior design, without any crevices etc. is beneficial since it provides a surface which is relatively easy to clean and sterilize. There may be other shapes possible than the one illustrated in the drawings, yet a nozzle head having crevices and such would be unsuitable for the purposes of the invention.
In order for the jets to pass through the opening 12 an additional solution was used. By displacing each through hole a set distance from a plane including the central axis of symmetry of the nozzle head 2, and have the through hole 10 extending parallel to this plane, the jets could be directed through the opening 12, while the through holes 10 could be maintained as rectilinear channels not interacting with each other. In this way it will be possible to arrange the through holes at a greater angle relative to the central axis of the nozzle head, since basically the entire extension of the nozzle head may be used. A greater angle relative to the horizontal makes it possible for the jets to impinge on the package walls far from the closed end of the package and a smaller angle relative to the horizontal makes it possible to impinge the package walls higher up. As a rule of thumb it is beneficial to hit the package walls as high up as possible without interfering with the portion of the package which will be included in the seal, i.e. the package sealing area. One benefit with the present embodiments thereof is that it may be used to fill packages without moving the packages vertically, towards the filling nozzle.
The cross section of Fig. 5 illustrates how close the through holes 10 are, in particular in the center of the nozzle head 2. It has been mentioned that the through holes 10 may have another shape, yet the rectilinear shape simplifies production of the nozzle head 2. The nozzle head 2 also includes flanges for fastening and recesses for accommodation of sealants, yet these components are obvious for the skilled person by observing the appended drawings.
Fig. 2 is a side view of a nozzle head 2 included in a filling assembly according to one embodiment. The same numbers have been used to designate like parts.
Fig. 3 is a top view of the nozzle head of Fig. 2, showing the inlets 32. The cross sections of Fig. 4 and 5 illustrate the path of the through holes 10 through the nozzle head 2.
Fig. 6 illustrates a portion of a filling station 38 in a filling machine, in which a filling assembly 1 is arranged. It should be noted that the number and configuration of the filling assemblies could differ from what is disclosed in Fig.6 without departing from the scope of the present invention as defined by the appended claims, e.g. one filling station could comprise more than one filling assembly, and the additional filling assemblies would not have to utilize the present invention. In the filling station 38 packaging containers 40 are filled with pourable product 42. The packaging containers 40 have an open bottom end, facing upwards, and the shape of the shoulders and opening device at the other end make them prone to induce splashing and foaming if a flow of pourable product is directed directly towards that region. The packaging containers are moved intermittently between filling units in a machine direction MD. The risk of splashing and foaming is greatest when filling pourable product 42 into an empty packaging container 40, which is why a nozzle head 2 according to one embodiment of the present invention is arranged to fill the pourable product 42 into the empty packaging container 40. The number of filling units, time at each filling unit, etc. is also defined by the process upstream the filling station, such as preheating, sterilization, and venting.
For some applications the nozzle will be arranged in an area which is heated and in which a significant flow of (dry) air prevails. Under these circumstances there may be a risk for product to build up in the channels 10, or in the nozzle outlets 36. This will deteriorate the properties if the nozzle, and thus measures may have to be taken to avoid this build up.
According to yet another embodiment the nozzle is provided with a cooling jacket 44, as shown in Fig. 7. The cooling jacket 44 is arranged outside of the nozzle head 2 and a cooling fluid, e.g. cooling water is allowed to flow through an annular slit 46 between the nozzle head 2 and the cooling jacket 44.
In the present embodiment a cooling channel 48 (see Fig. 8) is defined in the annular slit 46 by means of flanges 50 (Fig. 8) on the nozzle head 2. The flanges 50 extend radially outwards towards the cooling jacket 44 and the construction is readily understandable from studying the fold-out view of Fig. 8, in which the circumference of the nozzle has been parted between the cooling water inlet 45 and the cooling water outlet 47, and laid flat.
The flanges 50 extend from an upper part of the annular slit 46 created between the cooling jacket 44 and the nozzle head 2, to a lower part thereof. The length of each flange 50 is smaller than the height of the annular slit 46, such that a fluid passage may be created above and/or below the flange 50. By positioning the flanges 50 such that a main passage 52 is created on the upper side and the lower side alternately, the flow of the cooling fluid will be guided over the outer surface of the nozzle head 2 and cool the same in an efficient manner. In the illustrated embodiment a smaller passage 54 is arranged in an opposite relationship to the main passage 52 and thus a "shortcut" will be created, such that a flow of cooling fluid may be arranged to flow into corners where there otherwise would be a risk for the flow to stagnate. A stagnated flow, without significant exchange of cooling fluid, would act detrimentally on the cooling efficiency. The task of dimensioning the main passage and the smaller passage in order to achieve an adequate flow is a task which is readily solved by the skilled person. The flow is illustrated by the larger and smaller arrows indicated in Fig. 8.
The skilled person realizes that there are details in regard of the construction of the assembly that have been left out to increase readability. These left-out details, however, do not in any way obstruct for the skilled person to apply the teachings of the present description.
It should be noted that arranging lips around the nozzle outlets is not limited to the described shape or path of the through holes, neither to the number of through holes provided.
It should be stressed that there are other means for leading the product through the nozzle than circular channels (even if circular channels are preferred at present), such one or more slits.

Claims

A filling assembly (1), including
a nozzle head (2) for filling a liquid into a package (40) while minimizing splashing and foaming, said nozzle head (2) being adapted to fill liquid into a package (40) while being positioned above said package (40), the nozzle head (2) comprising an upper surface from which several inclined channels (10) extend, the channels (10) having a nozzle orifice (36) in their downstream end, such that a liquid jet injected through the channel (10) may be directed towards lateral walls of the package (40), and
a valve cone (26), wherein the channel inlets being distributed over the upper surface are closable by means of the valve cone (26), wherein the nozzle orifice (36) projects out from a bottom surface of the nozzle head (2), in the direction of the channel (10),
characterized in that the valve cone (26) has a rim (30) arranged to abut the inlets of the channels in a closed position, the valve cone further having an interior recess (28) in fluid contact with said upper surface of the nozzle head, wherein a passage (34) extends from the recess (28) through the valve cone (26), providing fluid contact between the recess and the valve cone surroundings.
The filling assembly of claim 1, wherein the passage (34) extends from an uppermost location of the recess (28).
The filling assembly of claim 2, wherein the nozzle orifice (36) has a diameter Do and a rim with a width W, preferably dimensioned such that 0.05<W/D_O<0.2, 0.05<W/D_O<0.1.
The filling assembly of any preceding claim, wherein the channels (10) are arranged parallel to a plane including the central axis of the nozzle head at a distance, d>0, from said plane.
The filling assembly of any one of claim 4, wherein said distance resides in an interval of D<d<X, where 2D is the diameter of the channel (10) and X is the diameter of the nozzle head (2).
The filling assembly of any preceding claim, wherein the several channels (10) are arranged as a set of channels distributed at a particular radius around a central axis of the nozzle head.
The filling assembly of claim 6, wherein more than one set of channels (10) is arranged, and wherein each set is arranged at a different radius.
The filling assembly of any preceding claim, wherein
a cooling jacket (44) is arranged radially outside of the nozzle head (2),
a cooling water inlet (45) and a cooling water outlet (47) is arranged to lead cooling water through an annular slit (46) created between the cooling jacket (44) and the nozzle head (2).
The filling assembly of claim 8, wherein flanges (50) of the nozzle head (2) extends radially outwards to the cooling jacket (47), the flanges (50) extending from an upper portion of the annular slit (46) to a lower portion thereof and defining a main passage (52) for cooling fluid above or below an end of the flange (50), in an alternating fashion, such as to guide a flow of cooling fluid.
The filling assembly of claim 9, wherein a second passage (54) smaller than the main passage (52) is arranged at the opposite end of a flange (50) in relation to the main passage (52).
A filling machine, including
a filling assembly (1) of any preceding claim,
a dish box (4) enclosing said nozzle head (2) and having an opening (12) arranged to allow passage of pourable product ejected from the nozzle head (2),
a conveyor arrangement arranged to convey packaging containers (40) having an open end directed towards the nozzle head (2), wherein the nozzle head is arranged such that it may eject pourable product into the packaging container (40) through said opening (12).
The filling machine of claim 11, wherein the conveyor arrangement is configured to convey the packaging containers along a rectilinear path, and hold the position of the packaging containers below an opening such that they may be filled while remaining on the rectilinear path.