EP0267458A1 - Nozzle with at least one closable nozzle opening - Google Patents

Abstract

Nozzle with at least one closable nozzle opening (10), in particular a filling nozzle (5) for filling machines and the like for liquid products and articles containing them. The nozzle comprises a valve body which is designed as a piston (9) and which is between a retracted position in which the opening is opened and an advanced position in which the piston projects into the opening (10) and closes it completely and is movable. In order to always be able to maintain a good fit between the piston (9) and nozzle opening (10) and to achieve precise guidance of the piston in order to be able to insert it precisely into the opening, the nozzle comprises a piston guide with at least two guide surfaces with two substantially opposing surfaces on the piston, and the piston (9) is axially split or slotted and includes biasing members (13) to urge the piston halves away from one another for sealing support against the walls of the nozzle opening (10).

Description

The present invention relates to a nozzle with at least one closable nozzle opening, in particular a filling nozzle for filling machines and the like for liquid products, with a valve body designed as a piston, which is located between a retracted position in which the opening is opened and an advanced position. in which the piston protrudes into the opening and completely closes it, it can be moved back and forth.

Nozzles of this type are used, inter alia, in machines for filling soups, creams, fruit compotes, sauces and the like, which can contain pieces of fruit, vegetables or meat, in packaging which is conveyed in rapid succession on a conveyor belt located under the nozzle opening. Since it is food, great demands are placed on hygiene and the nozzles must be sterilized at regular intervals. As a result, and also because the area around the nozzle is rather aggressive, partly because of fruit acids, the parts of known nozzles are made of stainless steel.

Since the products to be filled can in various cases consist of large pieces and also pieces of long-fiber products which have to be cut off in connection with the filling, it is necessary to have a very tight fit between the piston-shaped valve body and the Can maintain nozzle opening to obtain an effective cutting function between these parts. This tight fit means that the piston remains seated during the sterilization processes due to material expansion at the elevated temperatures in the nozzle opening or existing guides, in order to be able to move again only after the temperature has dropped to essentially normal operating temperature.

This can possibly be accepted as long as the sterilization can be carried out during idle times. Recently, machines have been developed in which it is desired that the piston be movable even during the sterilization processes, which is impossible with the previous piston designs and material selections if at the same time, the tight fit required for effective cutting is to be maintained.

The main object of the present invention is to provide a nozzle of the type mentioned above, which, while avoiding the disadvantages mentioned, combines, among other things, the advantages of a very effective cutting function with the possibility of the piston moving even during the sterilization processes. According to the invention, this object is generally achieved in that the piston is designed in such a way that its dimensions automatically adapt to the current dimension of the nozzle opening and piston guides.

A nozzle of the type mentioned in the introduction is therefore characterized according to the present invention by a guide for the piston, with at least two guide surfaces, which cooperate with two essentially opposite surfaces on the piston to guide the piston precisely into the nozzle opening, that the piston in the axial direction is split or slotted and that biasing members are arranged to press the piston halves away from each other for sealing support against the walls of the nozzle opening.

The precise guiding means that the piston can be inserted into the nozzle opening with high precision essentially without play to obtain a good cutting effect, the prestressing elements causing the dimension of the piston to adhere to the guide or the nozzle opening essentially independently of temperature movements and Adjust wear. It is expedient for the piston to be divided or slotted in an axial plane which extends between the surfaces of the piston which are located opposite one another and cooperate with the said guide surfaces. The guide surfaces preferably have the same shape as the walls of the nozzle opening and merge smoothly into the same.

In a preferred embodiment, the guide comprises a guide sleeve surrounding the piston and adjoining the nozzle opening, the walls of which are formed with openings that can be closed by the piston in the advanced position of the same, and a sealing element is provided to prevent leakage through the nozzle opening through the separation or to prevent the slit of the piston in the advanced position of the piston.

The sealing element expediently comprises a rubber seal which is arranged between the piston halves and which adjoins the shape of the outer boundary surfaces of the piston, at least on the part of the piston lying outside the guide. The sealing element can have the shape of a rubber washer with position-determining projections which interact with corresponding recesses in the piston halves. In order to avoid drops remaining on the front face of the piston, the rubber washer at the outer end of the piston can be formed with a thicker section which merges into one or more tips protruding outside the face of the piston.

When using a piston, the front end of which is slotted, the sealing element can be designed as a rubber ring which surrounds the rear, non-slotted part of the piston and, in the advanced position of the piston, cooperates in a sealing manner with a sleeve-shaped piston guide. The biasing members acting on the piston halves preferably comprise a resilient element arranged between the piston halves.

• Fig 1 zeigt schematisch eine Abfüllmaschine, teilweise im Schnitt, mit einer Düse gemäss der Erfindung.
• Fig 2 ist eine Detailabbildung der Düse gemäss Fig 1.
• Fig 3 ist ein Schnitt durch den Düsenkolben.
• Fig 4 zeigt ein beim Kolben gemäss Fig 3 verwendetes Dichtungselement.
• Fig 5 ist ein Schnitt durch den Kolben gemäss Fig 3 längs der Linie V-V.
• Fig 6 ist ein Schnitt durch eine abgeänderte Ausführungsform eines Düsenkolbens.
• Fig 7 zeigt die Düse gemäss der Erfindung mit einem Kolben gemäss Fig 6 während eines Arbeitshubes.

The invention is described below with reference to the embodiments shown as examples in the accompanying drawing.

• Fig. 1 shows schematically a filling machine, partly in section, with a nozzle according to the invention.
• FIG. 2 is a detailed illustration of the nozzle according to FIG. 1.
• Fig. 3 is a section through the nozzle piston.
• FIG. 4 shows a sealing element used in the piston according to FIG. 3.
• FIG. 5 is a section through the piston according to FIG. 3 along the line VV.
• Fig. 6 is a section through a modified embodiment of a nozzle piston.
• FIG. 7 shows the nozzle according to the invention with a piston according to FIG. 6 during a working stroke.

1 shows very schematically the principle of a filling machine in which a nozzle according to the invention is used. 1 denotes a container for a product that is to be filled in packs 2, which are conveyed in rapid cycle on a belt running under the filling machine. The product can consist, for example, of fruit compotes with pieces of fruit or soups with pieces of meat. 3 designates a valve which, in the schematic embodiment shown, is connected to the piston in a nozzle 5 according to the invention by an actuating rod 4. The rod 4 is effected by using an actuating cylinder 6 upwards and downwards. With 7 another cylinder is designated, which acts on a metering piston 8.

The working principle of this filling machine is as follows. When the piston rod moves down, the outlet openings of the nozzle 5 are closed and then the valve 3 is opened and the piston 8 begins its movement to the left in the figure, and this means that an amount determined by the movement of the piston 8 in the container 1 available product is sucked out of the container. The rod 4 is then moved upwards, so that the valve 3 closes the outlet opening of the container 1, after which the outlet openings of the nozzle 5 are opened and the piston 8 begins its movement to the right in the figure. A quantity of the product determined by the movement of the piston 8 will be filled into the respective packaging 2 located under the nozzle 5.

These work steps must be carried out in a rapid cycle and exactly in sync with the conveyance of the packs 2, in such a way that all packs are filled with the correct amount and without potting, which can spill the packs, and make subsequent hermetic sealing impossible can. Among other things, no half-cut product pieces should hang under the nozzle or drops of the latter may be released, which can fall onto the packaging.

Therefore, as mentioned above, a very tight fit between the piston-shaped valve bodies 9 entering the nozzle 5, see FIG. 2, and the associated nozzle openings 10 in the base plate 12 of the cylindrical nozzle housing 11.

In order to achieve a tight fit regardless of the wear of the pistons 9 and the walls of the openings 10 and without causing problems due to the thermal expansion, the piston 9 according to the present invention can be divided into two halves, see Fig. 3, which halves with are loaded by a biasing force, in the present example by a spring 13, which press the piston halves in the direction of one another and for support against the boundary walls of the openings 10. The dimensions of such a divided piston 9 will adapt to the dimensions of the openings 10.

In order to allow such a piston to be guided down into the openings 10 with great precision and high speed, however, very precise guidance of the piston movement is required. According to the present invention, as can be seen in FIG. 2, this can be effected using cylindrical guides 14, which guides have exactly the same internal dimensions as the openings 10, which guide surfaces merge continuously into the walls of the openings 10. The pistons 9 also come to seal on the inner walls of the guides 14, and in order to enable the product to be pressed out through the openings 10, the cylindrical guides 14 are provided with openings 15 on their lower parts. In the example shown, each guide 14 is provided with two opposite openings 15. These openings are closed by the pistons 9 when they move into the openings 10 in the plate 12.

Immediately above the openings 10, the guides 14 thus form two curved guide surfaces which cooperate with two opposite surfaces of the corresponding piston 9, since since the guide surfaces pass continuously into the opening 10 there is no risk of incorrectly centering the pistons relative to the openings 10. With regard to the sealing, it is recommended that each piston 9 is divided in an axial plane, which extends between the opposite guide surfaces mentioned and which continuously transition into the openings 10.

In order to prevent leakage through the nozzle opening due to the separation between the pistons, it is sufficient to provide a seal between the piston halves over the part extending above the guides 14. In Fig. 4, an expedient sealing element in the form of a rubber washer 16 is shown, which is provided for attachment between the piston halves and is designed with a width such that it closely adjoins the outer profile of the piston 9, see the section in Fig. 5. Die The rubber disc is designed with position-determining projections 17, which cooperate with corresponding recesses in the respective piston half, and has an opening 18 for the spring 13.

As an alternative to an entire rubber disk 16, one can use, for example, a rubber strip fixed in grooves in the piston halves and, for example, a frame-shaped rubber strip which extends along the edges of the piston halves. Such a rubber strip or the shown rubber washer also fulfills another essential function, namely as a shock absorber. If a piston 9 is to be advanced at high speed into the corresponding opening 10 while simultaneously cutting off a meat cube or similar, a radially inward force is obtained which compresses the piston halves to a certain extent against the action of the spring 13. It may be unsuitable to measure the spring 13 such that it resists an inward movement of the piston halves caused by an impact. However, the rubber washer or the rubber strip serves as an effective shock absorber that dampens the piston halves and prevents excessive compression of the same. If necessary, it is possible to completely replace the spring 13 with a rubber sealing element or to form or provide this with individual cushions made of elastic rubber material, which has the same effect as that of the spring 13. The rubber material can have different spring characteristics if it is exposed to impacts or slow-acting forces.

The piston 9 need not be entirely divided, but can be provided with a slot which extends over only part of the length of the piston, provided that the halves separated by the slot are slightly opposite can move each other. When using such a piston, if desired, instead of a sealing element arranged between the piston halves, an O-ring seal or the like can be used, which runs in a groove around the unslotted part of the piston, so that the seal at the bottom dead center of the piston Interaction with the associated guide 14 comes.

It is very important that the product pressed out by the piston 9 leaves the end face of the piston in the end position so that no drop gets caught. Because of the rapid movement of the piston as it rotates, this is usually not a problem. However, certain very sticky or sticky products can cause problems in this regard. In order to cope with this, the piston is formed with a tip 19 as shown in FIG. 6, which protrudes from the end face thereof. This can consist, for example, of the tip of a cylindrical rubber body which is inserted in a corresponding recess in the piston. The cylindrical rubber body with the tip 19 can be formed in one piece with the sealing washer 16.

FIG. 7 shows a nozzle according to the invention with a piston 9 according to FIG. 6 while the intended amount of product is being filled in a package 2 located under the nozzle opening. The piston 9 is shown in one position when it is just protruding into the opening 10, product pieces which are then intended to pass through the opening edge being effectively cut off due to the cutting function between the piston 9 and the edge.

The above-described embodiments of the piston and the guide thereof always ensure a precise fit between the piston and the edge of the opening 10 in order to achieve an effective cutting effect. This is essentially independent of temperature and degree of wear. With sterilization there is no problem with a device according to the invention.

By applying the invention, since the coefficient of thermal expansion is no longer so critical, it is possible to choose material with appropriate hardness for good cutting action, which also has a long service life. It may also be possible Choosing cheaper material than was previously possible.

In a prototype version, pistons made of TORLON and POLYSULPHONE were used with very good results, inter alia with regard to the cutting effect.

The embodiments described above and shown as examples can be varied in several ways within the scope of the invention. Thus, a nozzle according to the above can be designed with any number of pistons 9 and openings 10 and with the desired mutual attachment. The prestressing element can be of any design and, for example, can be replaced in a slotted piston by a spring action of the legs of the piston. In addition to a tip, the piston can be provided with several tips of the same or different sizes, depending on the current product, or with an irregularity of the piston surface caused in another way, which facilitates the release of the product from the surface. Split pistons with guides according to the invention can be used in other nozzles or devices, as is apparent to the person skilled in the art, in addition to filling nozzles of the embodiment shown.

Claims (10)

1. Nozzle with at least one closable nozzle opening (10), especially a filling nozzle (5) for filling machines and the like for liquid products, with a valve body designed as a piston, which is between a retracted position in which the opening is released and an advanced position , in which the piston (9) protrudes into the opening and closes it completely, can be moved back and forth, characterized by a guide (14) for the piston (9), with at least two guide surfaces , which are used to guide the piston precisely into the The nozzle opening (10) cooperate with two substantially opposite surfaces on the piston, that the piston (9) is divided or slotted in the axial direction and that prestressing members (13) are arranged to support the piston halves from each other for sealing support on the walls of the nozzle opening (10) to press away. 2. Nozzle according to claim 1, characterized in that the piston (9) is divided or slotted in an axial plane which extend between the surfaces of the piston which are opposite one another and cooperate with the said guide surfaces. 3. Nozzle according to claim 1 or 2, characterized in that the guide surfaces have the same shape as the walls of the nozzle opening and pass smoothly into the same. 4. Nozzle according to one of claims 1 to 3, characterized in that the guide comprises a guide sleeve (14) which surrounds the piston and adjoins the nozzle opening, and that the walls of the sleeve also pass through the piston (9) in the advanced position thereof closable openings (15) are formed. 5. Nozzle according to one of claims 1 to 4, characterized by a sealing element (16) for preventing leakage through the nozzle opening (10) by the separation or the slot of the piston. 6. Nozzle according to claim 5, characterized in that the sealing element comprises a rubber seal (16) arranged between the piston halves, which closely adjoins the shape of the outer boundary surfaces of the piston (9), at least on the part lying outside the guide (14) of the piston. 7. Nozzle according to claim 6, characterized in that the sealing element has the shape of a rubber washer (16) with position-determining projections (17), and that the piston halves are formed with corresponding recesses. 8. Nozzle according to claim 7, characterized in that the rubber washer (16) at the outer end of the piston (9) has a thicker section which merges into one or more tips (19) projecting outside the end face of the piston. 9. Nozzle according to claim 5 and with a piston (9) whose front end is slotted, characterized in that the sealing element is formed from a rubber ring which encloses the rear, non-slotted part of the piston and in the advanced position of the piston cooperates sealingly with a sleeve-shaped piston guide (14). 10. Nozzle according to one of claims 1 to 9, characterized in that the biasing members comprise a spring element (13) arranged between the piston halves.

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