A rotary joint for a rotary filling machine

Abstract

Sealing system (6) for the rotary connection of a rotary joint (1) of a rotary filling machine for filling a container with a pourable product; the sealing system (6) comprises along a radial direction (R): a slip ring (7) and a pair of energizing rings (8); wherein the pair of energizing rings (8) is arranged concentrically with respect to the slip ring (7).

Description

[0001] "A SEALING SYSTEM FOR THE ROTARY JOINT CONNECTION OF A

[0002] FILLING MACHINE AND A FILLING MACHINE COMPRISING SAID

[0003] SEALING SYSTEM"

[0004] FIELD OF THE ART

[0005] The present invention relates to a sealing system for the rotary connection of a rotary joint of a filling machine and a filling machine comprising said sealing system.

[0006] Preferably, the present invention has an advantageous (but not exclusive) application in the field of automatic machines in the food industry, in particular machines for filling pourable food products such as (non-exhaustive list) : carbonated liquids (such as sparkling water, soft drinks and beer) , non-carbonated liquids (such as still water, fruit juices, wine, tea, milk, flavoured water) , emulsions, suspensions, high-viscosity liquids and beverages containing pulp and / or solids.

[0007] More preferably, the present invention has an advantageous (but not exclusive) application to the sealing system of the rotary joint of a carousel, in particular the manifold joint, of the filling machine.

[0008] PRIOR ART

[0009] A commonly known filling machine substantially comprises a rotary conveyor (also known as a carousel) which rotates around a vertical axis , at least two chambers supported by the carousel conveyor and connected to a respective tank ( in particular, the tank is not supported by the rotary conveyor itsel f ) and a plurality of filling devices supported by the rotary conveyor, connected to the at least two chambers through respective fluid circuits and conveyed by the rotary conveyor along a circular conveying path . Each chamber is connected to the respective tank by means of the respective fluidic circuit , each of which i s provided with a respective rotary j oint provided with a sealing system, which prevents undesired leakage of the respective fluid supplied by the fluidic circuits at the rotary j oint .

[0010] The at least two chambers are preferably chosen from : a product chamber configured to contain the pourable food product , a cleaning chamber configured to contain a cleaning fluid, a pressurisation chamber configured to contain the pressurisation fluid of the container ( in particular to remove oxygen from inside the container ) and a depressurisation chamber configured to contain the depressurisation fluid ( in particular to depressurise the container after the pourable food product has been administered) .

[0011] At present , the sealing system comprises a slip ring (which faces , and acts against , a fixed part of the j oint ) and an energi zing ring ( speci fically a single O-ring) which is interposed between the slip ring and a movable part of the j oint .

[0012] The single O-ring has the disadvantage that it has an elastic constant ( also known as sti f fness ) which is very high and therefore the initial contact pressures are very high . However, after only a few decimals , the contact pressure drops dramatically, causing leaks .

[0013] In other words , with the passage of time , in view of the continuous stresses to which the sealing system is subj ected and in view of the relative rotation between the slip ring and energi zing ring, the sealing system (primarily the slip ring and secondarily the energi zing ring) of the sealing system can wear out . The wear and tear can lead to the respective rotary j oint no longer sealing properly, leading to undesired leakage of the transported fluids and / or contamination of the transported fluids through contaminants present in the environment . It therefore follows that even a relatively low degree of wear of at least one component of the sealing system ( slip ring or energi zing ring) can lead to an increase in the number of rej ected containers being filled by the filling machine and thus to a reduction in the productivity of the machine or even the plant .

[0014] DISCLOSURE OF THE INVENTION

[0015] A sealing system for a the rotary connection of a rotary j oint of a filling machine according to the present description or according to any one of the appended claims allows to reduce wear and the risk of leakage due to pressure variations .

[0016] A filling machine according to the present description comprises a sealing system according to the description .

[0017] BRIEF DESCRIPTION OF THE DRAWING

[0018] The present invention will now be described with reference to the attached drawings , which show a non-limiting embodiment thereof , wherein :

[0019] - Figure 1 is a schematic, perspective and sectional view of a rotary j oint part according to the present invention;

[0020] - Figure 2 is an enlarged schematic view of a sealing system of Figure 1 ; and

[0021] Figure 3 is a schematic diagram illustrating the force-displacement trend achievable with the sealing system of Figures 1 and 2 .

[0022] PREFERRED EMBODIMENTS OF THE INVENTION

[0023] In Figure 1 , the number 1 indicates overall a rotary j oint for a rotary filling machine (not illustrated) for filling, preferably under pressure , containers ( such as bottles , vials , j ars , cans or containers of this kind) with pourable products , such as (non-exhaustive list ) : carbonated liquids ( such as sparkling water, soft drinks and beer ) , non-carbonated liquids (such as still water, fruit juices, wine, tea, milk, flavoured water) , emulsions, suspensions, high-viscosity liquids and beverages containing pulp and / or solid pieces.

[0024] Rotary joint 1 is a hydraulic rotating manifold.

[0025] The filling machine comprises rotary joint 1 provided with an axis of rotation X.

[0026] Rotary joint 1 comprising a fixed body 2 and a movable body 3. Fixed body 2 and movable body 3 are concentric to each other with respect to axis X. Movable body 3 is configured to rotate about axis X with respect to fixed body 2. Fixed body 2 is immovable (viz., it does not move) .

[0027] Movable body 3 is arranged radially (viz., in a radial direction R which is transverse, in particular orthogonal, to axis X) more externally with respect to fixed body 2, as illustrated in Figure 1.

[0028] Rotary joint 1 (in particular its movable body 3) has in particular two radial through openings 4 through which a pressurised fluid can be fed to rotary joint 1 itself. Two through openings 4 are arranged in particular diametrically opposite each other.

[0029] Movable body 3 comprises at least one annular seat 5 (in particular two) configured to accommodate a sealing system 6 therein, as illustrated in detail in Figure 2. Two annular seats 5 are axially displaced from each other. Each annular seat 5 extends annularly at the inner surface of movable body 3. In particular, annular seat 5 is open and faces fixed body 2. In other words, movable body 3 has a cross-section with a substantially "C" shape.

[0030] Sealing system 6 comprises along radial direction R: a slip ring 7 and a pair of energizing rings 8. The pair of energizing rings 8 is arranged concentrically with respect to slip ring 7. Each annular seat 5 houses the pair of energizing rings 8 and slip ring 7. Slip ring 7 radially closes annular seat 5.

[0031] In particular, the pair of energizing rings 8 presses against slip ring 7, which in turn presses against fixed body 2.

[0032] The pair of energizing rings 8 and slip ring 7 are arranged radially in series. In particular, since the pair of energizing rings 8 are arranged in series, the overall elastic constant (stiffness) of both energizing rings 8 is lower with respect to the individual elastic constant (stiffness) of each energizing ring 8. More in particular, since two energizing rings 8 have the same elastic constant (taken individually) , the overall elastic constant (overall stiffness) of both energizing rings 8 is equal to half of the individual elastic constant (stiffness) of each energizing ring 8.

[0033] Figure 3 schematically illustrates a force-position diagram in which the elastic constant (stiffness) of a single energizing ring 8 is indicated with a solid line and the overall elastic constant (stiffness) of two energizing rings 8, which is lower (in particular equal to half) , is indicated with a dashed line.

[0034] Whereby, as schematically illustrated in Figure 3, for the same starting position (deformation) , the acting force is less, and therefore with time sealing system 6 moves more slowly along the f orce / position curve. This thereby increases the service life.

[0035] Instead, if it is decided to keep the starting force the same, the displacement or difference in deformation to reach a critical threshold will be greater, again resulting in this case in an increase in service life.

[0036] Therefore, for the same initial deformation (position) s, the starting force F' with two rings 8 (and thus pressure) is lower with respect to the force F with a single ring, and thus the reaction speed (viz., the movement speed of sealing system 6 over time along the line of the force-position diagram) is also lower, resulting in less wear. Instead, for the same initial force, there is more displacement or difference in deformation available during use. There is therefore less wear and tear in this case as well.

[0037] In addition, the series arrangement of the two energizing rings 8 allows to reduce the permanent stress of the energizing ring itself, because the deformation (displacement) of the two rings better exploits the available space, because the stress is distributed between the two rings 8.

[0038] Furthermore, by arranging the two energizing rings 8 in series, the contact pressure (force) exerted by the pair of energizing rings 8 against slip ring 7 is also reduced. As a result, as the contact pressure between the pair of energizing rings 8 and slip ring 7 is reduced, the wear of slip ring 7 itself is also reduced, as is the compression and consequent deterioration of each energizing ring 8.

[0039] Laboratory tests have shown that surprisingly, even with less pressure and therefore less force, sealing system 6 functions and ensures the required seal to prevent leakage. This allows to obtain very good performance even if one agrees to lower the initial force, leading to an increase in service life.

[0040] Both slip ring 7 and the pair of energizing rings 8 are gaskets configured to make the seal of rotary joint 1 itself.

[0041] Advantageously, each energizing ring 8 is a toroidal static seal.

[0042] Advantageously, each energizing ring 8 has a substantially circular cross-section.

[0043] Preferably, each energizing ring 8 is an O-ring. Thereby, since energizing rings 8 are a commercial element, it is possible to reduce the cost of sealing system 6, as no custom-made elements are required.

[0044] Slip ring 7 has a seat 9 at the side facing the two energizing rings 8. Seat 9 is configured to be partially engaged by energizing ring 8 facing it.

[0045] Seat 9 is defined by the concave surface of slip ring 7 (viz., curved facing towards axis X) .

[0046] According to the variant illustrated in the attached figures, slip ring 7 is arranged radially closer to axis X with respect to the pair of energizing rings 8.

[0047] Advantageously, in the preferred variant (which, however, is not limiting) , the first energizing ring 8 of the pair has a cross-section having a shape and dimension (in particular of what is called the chord) at rest which is equal to the shape and dimension at rest of the cross-section of the second energizing ring 8 of the pair. In other words, the two energizing rings 8 are essentially the same, they have only a different inner diameter to allow their concentric arrangement. In particular, the first energizing ring 8 of the pair has an inner diameter which is smaller with respect to the inner diameter of the second energizing ring 8.

[0048] Slip ring 8 has a cross-section with a substantially known shape and is therefore not described in detail below.

[0049] Sealing system 6 as well as rotary joint 1 described so far have a number of advantages.

[0050] Firstly, the presence of the two energizing rings 8 having the same shape and chord size allows the contact pressure to be reduced as described above.

[0051] Furthermore, sealing system 6 allows to increase the service life of the individual components (in particular the individual energizing rings 8) of sealing system 6 itself, reducing wear and tear as described above.

[0052] In addition, sealing system 6 reduces losses due to the wear and tear of the components of sealing system 6.

[0053] In addition, sealing system 6 also makes it possible to avoid or significantly reduce the risk of relative rotation (in particular slippage) of the slip ring with respect to energizing rings 8.

[0054] Sealing system 6 is easy and inexpensive to make.

Claims

CLAIMS1. A rotary joint (1) for a rotary filling machine for filling, preferably under pressure, containers with a pourable product; the rotary joint (1) comprising a fixed body (2) and a movable body (3) ; and comprising a sealing system ( 6 ) ; in which the movable body (3) is configured to rotate around an axis (X) with respect to the fixed body (2) , said axis (X) being an axis of rotation (X) defined by said rotary joint ( 1 ) ; wherein the sealing system (6) is for the rotary connection of said rotary joint (1) ; and wherein the sealing system (6) comprises, along a radial direction (R) with respect to said axis of rotation (X) defined by said rotary joint (1) : a slip ring (7) and a pair of energizing rings (8) ; wherein the pair of energizing rings (8) is arranged concentrically with respect to the slip ring (7) .

2. The rotary joint (1) according to claim 1, wherein the slip ring (7) is arranged radially closer to the axis (X) than the pair of energizing rings (8) .

3. The rotary joint (1) according to claim 1 or 2, wherein each energizing ring (8) is a toroidal static seal.

4. The rotary joint (1) according to claim 3, wherein each energizing ring (8) is an O-ring.

5. The rotary joint (1) according to any one of thepreceding claims, wherein the first energizing ring (8) of the pair has a cross-section having a shape and dimension at rest equal to the shape and dimension at rest of the crosssection of the second energizing ring (8) of the pair.

6. The rotary (1) according to any of the claims, wherein the first energizing ring (8) of the pair has an inner diameter that is smaller than the inner diameter of the second energizing ring (8) .

7. The rotary joint (1) according to any one of the preceding claims, wherein the two energizing rings (8) together have an elastic constant that is equal to half of the single elastic constant of each energizing ring (8) .

8. The rotary joint (1) according to any one of the preceding claims, wherein the two energizing rings (8) are arranged radially in series with respect to said axis (X) .

9. The rotary joint (1) according to any of the previous claims, wherein the slip ring (7) of the sealing body is arranged between the fixed body (2) and the pair of energizing rings (8) .

10. The rotary joint (1) according to any of the previous claims, wherein the joint (1) is a hydraulic rotating manifold.

11. Rotary filling machine for filling, preferably under pressure, containers with a pourable product; themachine comprises a rotary joint (1) according to any one of claims 1 to 8.

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