EP0060753B1 - Dosing devices for canning products - Google Patents

Description

The filling of cans or the like with pasty or heterogeneous semi-liquid jam-type products with pieces of fruit, animal food based on pieces of meat, food for human beings comprising pieces of meat or vegetables poses problems of regularity of dosage. It is known, in fact, that some of the machines used to date have on a rotating support a plurality of metering chambers each consisting of a cylinder and a piston functioning as a pump. The rooms are generally arranged vertically. In this configuration, the upward stroke of the piston causes a suction of the product through a supply duct coming from a reservoir containing it and generally placed in the center of the support, while the downward stroke pushes the product towards the box to be filled. by a discharge pipe. A valve makes it possible to selectively establish and interrupt communication between the chamber and one or the other of the two conduits.

The precision of the dosage depends on a large number of factors. It is in fact dependent on the regularity of the suction, the nature of the product, the effect of the centrifugal force on the product when the machine is running and the constancy of the displacement (depending on the constancy of the piston stroke and its regularity over time). The regularity of the suction is influenced by the presence or absence of residual air in the chamber or in the discharge duct close to the chamber. It is also influenced by the section of the suction channel whose dimensions must allow the passage of pieces of product, which are of irregular size while remaining in dimensions such that the conduits do not have a prohibitive size for a geometry of given machine. This geometry is in fact imposed in particular by the size of the boxes to be filled which are brought practically side by side under the rotating support in order, for a given production rate, to limit their linear speed as much as possible.

Finally, the centrifugal force acts on the product induced within it a whole system of forces which are difficult to control and which are added vectorially to the controlled suction and delivery forces and randomly modify the conditions and characteristics. The regularity of dosing and filling is affected.

Dosing devices with these drawbacks are known from French patent application No 74/37915 (published under No 2252253) and from American patent No 3841363. In the machines described there, the conduit connecting each metering chamber to a associated filling nozzle is contained in a radial plane, moving towards the axis of the machine in the plane passing through the axes of said chamber and said nozzle. By the same token, the feed duct of the metering chamber is contained in the same radial plane.

To remedy these drawbacks and optimize the operation of this type of machine, the present invention proposes an improvement whose object is, on the one hand, to eliminate as much as possible the presence of air which reacts in an elastic body, occupies a variable volume according to the pressure conditions to which it is subjected and, on the other hand, to take into account positively and, thus, controllable, the effects of centrifugal force.

To this end, the invention therefore relates to an improvement to metering devices for products to be fitted comprising a substantially vertical metering chamber mounted on a rotary support around an axis substantially parallel to the axis of said chamber, constituted by a tubular enclosure. in which a piston slides, said chamber being connected at its lower part by a supply duct to a reservoir of product to be fitted and by a discharge duct to a vertical cylindrical filling nozzle, in which a secondary piston is mounted, the delivery conduit opening into this endpiece by a lateral opening entirely situated above the orifice of communication of this conduit with said chamber, while a controlled valve ensures the establishment or interruption of communication of at least the supply line with the metering chamber. According to one of the essential characteristics of the invention, said nozzle is disposed between the reservoir and said chamber in front of the latter with respect to the send of rotation of the support, the direction of said delivery conduit being substantially radial, while said supply conduit connecting said reservoir to said chamber has a portion adjacent to said direction reservoir inclined rearward relative to said direction of rotation.

In addition, in order to improve the filling qualities of the metering chamber by reducing the obstacles to the circulation of the product, the aforementioned valve consists of a bottom part of said metering chamber, mounted for rotation in the enclosure. tubular by means of a cylindrical skirt provided with an opening for uncovering and closing, depending on its position, at least the orifice through which the supply duct opens into said chamber.

In addition, the angular width of the opening of the aforementioned cylindrical skirt and the angular spacing of the orifices through which the supply and discharge conduits open at the base of the aforesaid chamber are of dimensions such that, when one realizes closing one of these openings, the discovery of the other is made simultaneously; this ensures the isolation of the metering chamber at the time of aspiration, thus avoiding depressurizing the air which may be contained in the upper part of the delivery duct.

In another embodiment, the filling nozzle comprises a rotary inner jacket provided with an orifice capable of being placed in coincidence with the lateral opening of the discharge conduit in the endpiece and moved relative to this opening under the effect of rotation of the jacket to constitute a means for gradually closing the discharge conduit. Provision will then be made for said orifice of the liner to have at least one edge which, during said rotation, cooperates with said opening in order to progressively reduce its section while raising the threshold. In this case, the progressive closing of the opening by the jacket is carried out during the last part of the delivery stroke of the metering piston and the total closure is carried out immediately after the said piston has reached its bottom dead center.

The invention will be better understood during the description given below by way of purely indicative and nonlimiting example which will make it possible to identify the advantages and secondary characteristics thereof.

• la fig. 1 est une vue partielle en coupe horizontale d'un premier mode de réalisation du perfectionnement selon l'invention;
• la fig. 2 est une coupe selon II-II de la fig. 1, dans laquelle les éléments mobiles d'obturation des canaux sont dans une autre position;
• la fig. 2A est une vue partielle suivant F d'un détail de la fig. 2;
• la fig. 3 est une variante de réalisation du dispositif représenté aux fig. 1 et 2;
• la fig. 4 illustre, par une coupe IV-IV de la fig. 3, l'appareil en position de fin de refoulement;
• la fig. 5 illustre, par une vue partielle, la commande des éléments de tiroir ou de piston de la machine perfectionnée selon l'invention.

Reference will be made to the accompanying drawings, in which:

• fig. 1 is a partial view in horizontal section of a first embodiment of the improvement according to the invention;
• fig. 2 is a section on II-II of FIG. 1, in which the movable elements for closing the channels are in another position;
• fig. 2A is a partial view along F of a detail in FIG. 2;
• fig. 3 is an alternative embodiment of the device shown in FIGS. 1 and 2;
• fig. 4 illustrates, by a section IV-IV of FIG. 3, the device in the end of delivery position;
• fig. 5 illustrates, in a partial view, the control of the drawer or piston elements of the improved machine according to the invention.

Next to fig. 1 and 2, it will be recalled first of all that it is known to dose a product to be fitted by means of a machine mainly comprising a support rotating around a vertical axis 1, a plurality of substantially vertical metering chambers 2 integral of said support and a central tank 3.

In each of the chambers 2-essentially constituted by a tubular enclosure- a piston 4 is capable of sliding under the impulse of a control mechanism which will be explained below. The base of the chamber 2, closed by a bottom piece 2a, can be placed in communication with a supply duct 5 and a delivery duct 6 for the product to be fitted in metered quantity. The supply duct 5 comes from the reservoir 3, while the delivery duct opens into a cylindrical and vertical end piece 7 under the end 7a of which the box to be filled is placed. In this end piece, a secondary piston 8 (or slide) is slidably mounted between two positions, namely a low position in which its front face 8a is contained in the face 7a of the end piece and a high position in which said front face 8a is just at the upper edge of the lateral opening 6a through which the conduit 6 opens into the end piece 7. In addition, this opening 6a is such that it is completely located above the orifice 6b through which the conduit 6 opens at the base of the chamber 2 and a fortiori above the front face 4a of the piston 4 when the latter is at its bottom dead center, that is to say at the end of the delivery stroke or at the start of the suction stroke (see mixed line 4'a in fig. 2).

After recalling these known arrangements, the characteristics of the invention will be indicated below. One of them resides in the arrangement of the discharge conduit 6. It will have been noted that in operation the conduit 5, the metering chamber and the conduit 6 contain the product to be fitted and that these elements rotate around the axis 1.

Due to the rotation of the assembly, the product is subjected to a significant centrifugal force. The effect of this force goes in the direction of filling the metering enclosure in the conduit 5. It will be noted in this regard that the part 5a of the conduit 5 adjacent to the reservoir 3 has a general direction D (fig. 1) inclined backwards with respect to the direction of rotation R of the machine. This orientation is very favorable for the penetration of the product because it corresponds substantially to the direction of the result of the forces applied to the product in this area. We realized that, in order to properly control the delivery of the product, it was necessary for the latter to be driven back only under the influence of the piston 4. As it is not possible to remove the effect of the centrifugal force, the discharge conduit has been placed in an area such that the centrifugal force at least partially opposes the discharge force. Thus, according to one of the characteristics of the invention, the conduit 6 will be placed inside the cylinder described by the axis of the chamber 2 around the axis 1. In fact, beyond this limit, the centrifugal force will give rise in the delivery duct to a product flow tendency without action of the piston 4 and may cause spontaneous emptying of the duct 6 which, because of the arrangement of the opening 6a, has the shape of a siphon. We will make the most of the centrifugal force acting as the product retaining force if we place the duct 6 as shown in fig. 1, i.e. in an almost radial direction (towards axis 1). The nozzle 7 will advantageously be placed in front of the axis of the chamber 2 relative to the direction of rotation R of the machine. Thus the duct 6 will have a general direction close to the radial direction but nevertheless slightly inclined towards the rear to favor the return to the chamber 2 of the product under the effect of the forces generated by the rotation. During delivery, it can be seen that the peg 4 therefore acts against a resistant force, which, from experience, is a factor in good dosing. In addition, one of the effects of the centrifugal force on the product contained in the conduit 6 according to the invention lies in the theoretically inclined conformation (see line 9 in Fig. 2) of the free surface of the product in the vicinity of the opening 6a. As will be seen below, this inclination is a factor favorable to the proper functioning of the metering, since it makes it possible to obtain a filling of the conduit 6 (in the part superior of the siphon that it forms) spontaneously superior to that produced by a product with a horizontal free surface.

The radial arrangement of the discharge conduit as it appears in FIG. 1 increases the circumferential size of each dosing head. However, the spacing d which separates two successive nozzles is determined, on the one hand, as a function of the radius of circulation of the boxes with the machine which cannot fall below a certain value without compromising their automatic routing and, d 'on the other hand, the value of the width or diameter of these boxes. The distance d is slightly greater than the value of this diameter in order to have, for a given radius, a maximum of boxes under all of the heads of the machine. It is necessary, in this space, to house a suction pipe 5 and a delivery pipe with the largest possible sections for the passage of pieces of product (meat or fruit). It is also necessary to avoid creating choke points on these transfer channels. The solution to all these problems offered by the invention lies in the design of the valve which ensures at least the communication of the enclosure 2 with the duct 5 and its isolation from this duct. This valve is constituted by the bottom part 2a which is rotatably mounted at the base of the tubular enclosure 2. This part has at its upper part a cylindrical skirt 10 which has a lateral opening 11 which, depending on the angular position of the part 2a, is located opposite the supply channel 5 or opposite the discharge channel 6. It will be noted in FIG. 1 that, in the open position of the channel 5, the notch 11 does not completely block the delivery channel 6. This arrangement may be desirable, on the one hand, to avoid shearing or jamming of certain parts of the product and, on the other hand, to assist in the final filling phase. In another embodiment (see fig. 3), the opening and closing of the duct 6 during the closing and opening of the channel 5 are carried out completely by the skirt 10 and the notch 11. The maneuver in rotation of this valve is provided by a lever 12 provided with a roller 13 capable of cooperating during the rotation of the machine around the axis 1 with a fixed cam surface not shown.

In order to isolate the duct 6 with respect to the outside, in particular at the end of the filling phase of the enclosure 2, when the secondary piston 8 is brought back in the vicinity of its top dead center thus discovering the opening 6a and in the case of fig. 1, a rotary jacket 14 provided with a lateral opening 15 has been placed in the end-piece 7. Depending on the angular position of said jacket, the opening 15 is placed opposite or next to the opening 6a, thus opening or closing the communication of the conduit 6 with the end piece (open, see fig. 2; closed, see fig.). The rotation of the jacket 14 is for example ensured by the cooperation of a toothed wheel 16 which is integral with it with a toothed sector 17 integral in rotation with the part 2a. Thus, the control of the jacket 14 is coupled to the control of the valve 2a.

Finally, note in FIG. 2A which is an external view of the end piece (along F) at the opening 6a, that the openings 6a and 15 are of shapes such that a relative rotation restricts the passage section by raising the threshold 18. This arrangement has the advantages below: When the piston 4 is actuated downwards, the chamber 2 is placed in communication with the conduit 6 (with the concomitant closure of the conduit 5) and the openings 6a and 15 facing the one of the other. The product therefore flows through the channel 6 in the nozzle 7 towards the box. At the end of the delivery, the rotation of the valve 2a is started by the lever 12, without however closing the duct 6 due to the angular width of the opening 11, and, at the same time, the rotation of the shirt 14 which causes the opening of the opening 6a to close. There is then a constriction for the flow of the product at this level which, due to the substantially constant flow of the discharge, creates a slight overpressure in the duct 6. This overpressure has the effect of improving the filling of this duct by confining the air which would be housed in the upper part of the siphon (appreciably above the line 9) in a more reduced space and forcing it to pass above the threshold 18 which rises, entrained by the product. When the piston 4 comes to its bottom dead center (4'a), the opening 6a is almost completely closed and the piston 8 descends into the nozzle 7 to empty the product which is retained there.

It can be seen that this succession of operations made it possible to purge the duct 6 of the air which it could contain and, thus, to create conditions favorable to good suction. When the dosing head is in the conditions of fig. 1, the rise of the piston 4 creates a suction of the product from the reservoir 3 through the conduit 5. At the same time, the product contained in the conduit 6 is subjected to a vacuum. The air which it could have contained would then have increased in volume and therefore taken the place of the product by modifying the dosage quantity, of an uncontrolled value, a disadvantage which is eliminated by the purge described above. In this way, the quantity of product dosed can be kept constant with good precision.

Next to fig. 3 and 4 on which appear some of the above-described members described with the same references, it can be seen that the end piece 7 no longer has a rotating jacket and that the skirt 10 of the part 2a has an opening 11 which coincides with the outlets of the conduits 5 and 6 in the chamber 2. Thus, these conduits are respectively and selectively completely open or closed by the valve 2a.

In the case of the fig. 1 and 2 comprising a rotary jacket, the aforementioned opening 6a is kept closed if there are no boxes under the end piece 7. In fact, in known manner, the operation of the lever 12 is subject to the presence of a box. If this is not found ted, the lever is not actuated and the chamber 2 remains in communication with the reservoir. There is then no need to provide for the closure of the opening 6a by the secondary piston 8 in the absence of a box, which simplifies its control device and the piston 8 will operate in an identical manner in the presence or in the absence of boxes. This arrangement is particularly advantageous for a high speed of rotation of the machine because it allows a control system by guide path (see FIG. 5) with gentler slopes for the secondary piston 8.

For the realization according to fig. 3 and 4 insofar as the operation of the secondary piston is not enslaved to the presence or absence of a box, the opening 6a will be discovered. However, taking into account the orientations according to the invention of the conduits, the product remains maintained in the conduit 6 to a minimum loss which does not prohibit the dosing precision. We can for lower speeds of rotation enslave the operation of the secondary piston 8 to the presence or absence of gearbox to keep this opening closed and thus eliminate any loss of product, however small it may be.

We will refer to fig. 5 on which there is schematically shown the control members of the movements of the aforementioned pistons. In this figure, we see the piston rods 8a and 4b of the pistons 8 and 4 slidably mounted in a support 18 secured to the central reservoir 3 and rotating with it. Each of these rods laterally carries a roller 19 and 20 capable of rolling on a raceway 21a, 21b and 22a, 22b which is fixed on a support structure belonging to the fixed frame of the machine. These raceways therefore constitute guides to said rollers and control the raising and lowering of the pistons 4 and 8 by the appropriate slopes which they affect during the rotation of the pistons around the axis of the machine. It is understood that the paths 21 a and 22a control the elevation of the pistons, while the paths 21 b and 22b control their descent.

It is therefore sufficient to give these guides a profile adapted to the stroke and to the speed of the desired pistons, taking into account a constant speed of rotation. We can also provide these guides in several sections to allow the adaptation of one or more parts of these guides to the desired kinematics of the pistons, or even to allow modification.

The invention finds an interesting application in the field of casing. It is not limited to the description which has just been given, but on the contrary covers all the variants which would be made to it without departing from its scope.

Claims (7)

1. Device for measuring the quantity of products for canning comprising a quantity-measuring chamber (2) which is substantially vertical and mounted on a support rotating about an axis (1) substantially parallel to the axis of said chamber, said chamber consisting of a tubular enclosure inside which slides a piston (4), and having its lower part connected via a supply conduit (5) to a supply tank (3) containing the product for canning, and via a delivery conduit (6) to a vertical cylindrical filling nozzle (7), in which slides a secondary piston (8), said delivery conduit (6) issuing into said nozzle through a lateral opening (6a), a controlled valve (2a) opening or closing a passage between at least the supply conduit (5) and the measuring chamber (2) characterized in that the lateral opening (6a) is entirely situated above the orifice bywhich said conduit (6) communicates with said chamber (2), and in that said nozzle (7) is situated between the tank (3) and said chamber (2), before the latter with respect to the direction (R) of rotation of the support, the direction of said delivery conduit (6) is substantially radial and the supply conduit (5) connecting said tank (3) with said chamber (2) has a part (5a), adjacent the said tank (3), of direction (D) backwardly inclined with respect to said direction (R) of rotation.

2. Device according to Claim 1, characterized in that the said valve (2a) consists of a bottom part of the measuring chamber, which part is rotatably mounted inside the tubular enclosure (2) by means of a cylindrical skirt (10) provided with an opening (11) to cover or uncover, depending on its position, at least the orifice through which the supply conduit (5) issues into the said chamber.

3. Device according to Claim 2, characterized in that the angular width of the opening (11) of the said cylindrical skirt (10) and the angular distance between the orifices through which the supply (5) and delivery (6) conduits issue into the bottom of said chamber (2) are so dimensioned that when one of said openings is closed, the other is simultaneously opened as a result.

4. Device according to any one of Claims 1 to 3, characterized in that the filling nozzle (7) comprises an inner rotary liner (14) provided with an orifice (15) operable to move into alignment with the side opening (6a) of the delivery conduit in the nozzle and to be moved with respect to said opening under the effect of the rotation of the liner to constitue means for gradually closing the delivery conduit (6).

5. Device according to Claim 4, characterized in that said liner orifice (15) comprises at least an edge which during said rotation, cooperates with said opening to gradually reduce the section thereof whilst raising its threshold (18).

6. Device according to Claim 5, characterized in that the gradual closing of the opening (6a) by the liner (14) is achieved during the last part of the delivery stroke of the quantity measuring piston (4) and full closure is achieved immediately after said piston has reached its bottom dead center.

7. Device according anyone of Claims 4 to 6, characterized in that the means for rotating said liner (14) consist of a toothed wheel (16) meshing with a segment gear (17) born by the valve-forming rotary bottom piece (2a) of the quantity-measuring chamber.

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