WO2002100719A2

WO2002100719A2 - Dosing device in a tube filling machine

Info

Publication number: WO2002100719A2
Application number: PCT/EP2002/006326
Authority: WO
Inventors: Martin Heinrich Heitlinger
Original assignee: Iwk Verpackungstechnik Gmbh
Priority date: 2001-06-13
Filing date: 2002-06-10
Publication date: 2002-12-19
Also published as: ES2235069T3; ATE287825T1; CA2450537A1; WO2002100719A3; DK1395490T3; DE10128669A1; US20040251279A1; EP1395490A2; DE50202119D1; EP1395490B1; JP2005521598A; AU2002320836A1

Abstract

The invention relates to a dosing device in a tube filling machine, comprising a dosing chamber (13) embodied in a housing (11), said chamber having an inlet (14) and an outlet (15) for the medium which is to dosed. At least one adjustable dosing piston whose volume in the dosing chamber (19, 20) is adjustable is provided in addition to a control bushing (18) which is rotationably mounted in the housing, comprising at least one connecting channel (18b, 18c) which joins the inlet or the outlet to the dosing chamber when the control bushing is in a predetermined rotating position. The control bushing (18a) has a conical section which is sealingly arranged on a complementary conical section (12a) of the dosing chamber and which can be raised therefrom, in addition to an axial through hole (18d) wherein the at least one dosing piston is displaceably guided. At least one section of the dosing chamber is embodied on the side next to the wider end of the conical section of the control bushing, so that the conical sections are tensed against each other when the pressure in the dosing chamber is increased as a result of a movement in the dosing piston.

Description

Dosing device in a tube filling machine

The invention relates to a metering device in a tube filling machine, with a metering chamber formed in a housing, which has an inlet opening and an outlet opening for a medium to be metered, at least one adjustable metering piston, by means of which the volume of the metering chamber can be changed, and one rotatably mounted in the housing Control sleeve which has at least one connecting channel which connects the inlet opening or the outlet opening to the metering chamber in a predetermined rotational position of the control sleeve, the control sleeve having a conical section which can be sealingly applied to and detached from a complementary conical section of the housing.

A tube filling machine is used to fill tubes with a predetermined, metered amount of a product or filling medium and usually has a conveyor device designed as an endless belt or chain, which carries a large number of receptacles for one tube each. The empty tubes are inserted into the receptacles of the conveyor device in a loading station and then pass through several rere workstations, which are in particular a filling station and a downstream sealing station. In the filling station, the tubes are filled via a filling pipe, which is connected to a filling medium reservoir via a dosing device. The filled tube is then transported on to the closing station, in which the upper end of the tube is closed.

A metering device of known construction (DE 36 36 804 CI) has a housing which is connected to the filling medium reservoir via an inlet opening and to the filling pipe via an outlet opening. A control sleeve is rotatably mounted in the housing, in the interior of which a metering chamber is formed which has an access opening which, depending on the rotational position of the control sleeve, is optionally connected to the inlet or outlet opening. A metering piston is displaceably mounted within the control sleeve, which draw a predetermined amount of the filling medium through the inlet opening into the metering chamber when the outlet opening is closed, and then when the outlet opening is closed

Push the inlet opening through the outlet opening and thereby insert it into the tube to be filled. Intermittent opening and closing of the inlet and outlet openings is effected by turning the control sleeve.

The control sleeve is sealed with respect to the housing by means of ring seals and moreover has a conical section which bears against a complementary conical section of the housing. The control sleeve is closed at one axial end and connected to an adjusting device by means of which it can be axially adjusted so that the two conical sections come to rest.

If the quantity of filling medium to be dosed is to be changed, it is usually necessary to use the dosing piston to replace, which is labor intensive and therefore costly, especially since the tube filling machine is idle during this time. However, it is even more complex if a change to another filling medium is to take place in the tube filling machine after the filling of a first filling medium, since it is necessary for hygienic reasons to completely clean the filling unit and thus also the dosing device from residues of the first filling medium , Whereas in the past the dosing device was completely removed from the tube filling machine and cleaned by an operator, the cleanliness to be achieved depending on the quality of the operator's work, DE 36 36 801 CI provides for the control sleeve to be axially closed by means of the adjusting device adjust that the housing, the control sleeve and the dosing piston are brought from the normal working position into a cleaning position, in which they come free from each other and the seals coming into contact with the filling medium to be dosed are exposed. By introducing a cleaning liquid, the components and the seals can then be cleaned of residues of the previously filled filling medium. However, the installation space required for the adjustment device is very large and it has also been shown that the seals are subject to high wear and tear due to the cleaning process and therefore have to be replaced frequently, which in turn is time-consuming and expensive.

The invention has for its object to provide a metering device of the type mentioned, which has a compact structure and enables a product change in a simple manner.

This object is achieved according to the invention with a metering device of the type mentioned, which has the characterizing features of claim 1. In the metering device according to the invention, the seal between the control sleeve and the housing is achieved alone or at least predominantly by the sealing contact of the conical sections of these components " ^* In this way, a reliable and permanent seal between the control sleeve and the housing can be achieved by the two conical sections are clamped against each other, so that the two conical sections in contact are free from each other

Control sleeve to be axially displaced by a small amount, whereby a gap is formed between the conical sections, which can be rinsed out with a cleaning liquid. The control sleeve is then moved again in the opposite direction, so that the two conical sections of the control sleeve and the housing come into sealing contact again. In this way, special elastic plastic seals can be dispensed with, which means that there is no longer any risk of excessive wear and the need to change the seal.

A particularly compact embodiment of the metering device is achieved in that the control sleeve has an axially through-bore in which the at least one metering piston is displaceably guided. The metering piston is accommodated with a piston section in the axial through-hole with a tight fit and thus sealed, so that no special plastic seals are necessary here either.

The metering chamber is formed at least in sections on the side facing the wider end of the conical section of the control sleeve. When the filling medium in the dosing chamber is pushed through the Outlet opening into the filling nozzle and thus the tube is pressed, the pressure in the metering chamber increases. This pressure is used according to the invention in that the two conical sections of the control sleeve and the housing are tensioned or pressed against each other, which on the one hand ensures the sealing effect between the housing and the control sleeve and on the other hand also leads to a higher dosing accuracy with low-viscosity products ,

Particularly good sealing properties can be achieved if the housing and / or the control sleeve and / or the metering pistons consist of a ceramic material.

In a further development of the invention, two coaxial metering pistons are provided, of which a first metering piston is designed as an annular piston guided in the axial through bore of the control sleeve, which in turn has an axial bore in which a second metering piston is guided in a displaceable manner.

This configuration has the essential advantage that the amount of the filling medium conveyed to the tube via the outlet opening of the metering chamber can be changed in a simple manner without changing the metering piston. If the two coaxial dosing pistons are moved as a unit, a relatively large amount of filling medium is delivered. However, if the outer first metering piston, which is ring-shaped in cross section, stops and only the inner second metering piston is adjusted, a substantially smaller amount of filling medium is delivered. Alternatively, however, it is also possible to leave the inner second metering piston standing and only to adjust the outer ring-shaped first metering piston, which in turn pumps a different amount of filling medium which is preferably larger and in particular twice as large as the amount of filling medium which is conveyed solely by the inner second metering piston. Each metering piston is preferably assigned its own drive, in particular in the form of a servo motor.

In a further development of the invention it is provided that a flushing chamber of enlarged diameter is formed in the axial through bore of the control sleeve, in which a piston section of the first metering piston can be received with play, and that a flushing liquid can be supplied to the flushing chamber via at least one feed opening. In the cleaning position, the annular first metering piston is moved so far within the axial through bore of the control sleeve that its piston section lies freely in the washing chamber. The inner second metering piston remains stationary and, due to the displacement of the first metering piston, protrudes freely therefrom, so that the inner second metering piston can also be cleaned when a rinsing liquid is introduced.

When the control sleeve is axially displaced, the two conical sections disengage and an intermediate space is formed between the housing and the control sleeve, which can be flushed with a rinsing liquid for cleaning the metering device. The rinsing liquid is preferably introduced into a separate feed opening which is formed in the foot region of the conical section of the housing.

In one possible embodiment of the invention, a En ^¬ de protrudes the control sleeve into the metering chamber into and the communication passage, a connection between the metering chamber and the inlet opening or the outlet opening can be produced by means of which then can be switched on in a constructively acher form of an axial groove opening on the face.

Although a connecting channel or an axial groove is sufficient to selectively connect the inlet opening or the outlet opening to the metering chamber, in order to achieve the shortest possible and fastest adjustment movements of the control sleeve, it is useful to provide at least two connecting channels or axial grooves, these being arranged such that in no position, both the inlet opening and the inlet opening are connected to the metering chamber.

The conical section of the control sleeve is preferably formed at the axial end protruding into the metering chamber, the axial grooves also being provided in the conical section of the control sleeve.

Further details and features of the invention are apparent from the following description of an embodiment with reference to the drawing. Show it:

FIG. 1 shows a vertical section through a metering device according to the invention in the starting position,

FIG. 2 shows a top view of the metering device according to FIG. 1 with the cover removed,

FIG. 3 the dosing device according to FIG. 1 at the end of the intake stroke,

FIG. 4 shows a top view of the metering device according to FIG. 3 with the cover removed, FIG. 5 the dosing device according to FIG. 1 at the end of the delivery cycle,

FIG. 6 shows a top view of the metering device according to FIG. 5 with the cover removed,

FIG. 7 the dosing device according to FIG. 1 at the end of the intake stroke in a first alternative operating mode,

8 shows the dosing device according to FIG. 1 at the end of the intake stroke in a second alternative operating mode and

9 shows the dosing device according to FIG. 1 in the cleaning position.

1, a metering device 10 in a tube filling machine comprises a housing 11, which is held on a carrier 17, not shown. An axial bore 12 is formed in the housing 11, which continuously widens conically in the upper region of the housing 11. This conically widened section 12a of the axial bore 12 defines in its interior a metering chamber 13 which is sealed at the upper end of the housing 12 by a cover 16.

In the central region of the conical section 12a, a radial inlet opening 14 is formed in the housing 11, through which a filling medium can be introduced into the metering chamber 13, as indicated by the arrow M. Diametrically opposite to the inlet opening 14, a radial outlet opening 15 is formed in the housing 11, through which the filling medium can be pressed out of the metering chamber 18 to a filling nozzle, not shown, as indicated by the arrow F in FIG. 5 is indicated. In the lower region of the conical section 12a, ie in the transition between the axial bore 12 and its conical section 12a, a radial bore 11a is formed in the housing 11, which is connected to a supply of flushing liquid, not shown.

In the axial bore 12 of the housing 11, a control sleeve 18 is inserted, which is seated with a lower circular cylindrical portion with a tight fit in the axial bore 12 and has a conically widened portion 18a at the upper end, which has the same pitch angle as the conical portion 12a of the axial bore 12 has. The metering chamber 13 is formed between the upper end face of the conical section 18a of the control sleeve 18 and the cover 16.

Fig. 1 shows the control sleeve 18 in its lower position, in which its conical section 18a sealingly abuts the conical section 12a of the axial bore 12. In the conical section 18a of the control sleeve 18, two axial grooves 18b and 18c (see FIG. 2) opening at the upper end face thereof are formed, the width of which essentially corresponds to the width of the inlet opening 14 and the outlet opening 15 and extends up to whose foot area extend. The two axial grooves 18b and 18c are offset by an angle of approximately 135 ° in the circumferential direction of the control sleeve. When the control sleeve 18 is in the position shown in FIGS. 1 and 2, in which the axial groove 18b establishes a connection between the inlet opening 14 and the metering chamber 13, the connection between the metering chamber 13 and the outlet opening 15 is interrupted at the same time. When the control sleeve is rotated gersinn from the position shown in Fig. 2 position by an angle of about 45 ° in the Time ^¬ 18, characterized the connection between the Einlaßöff ung 14 and the metering chamber 13 is interrupted and instead the connection between the metering chamber 13 and the outlet opening 15 is established.

A central axial through-bore 18d is formed in the control sleeve 18, which is widened in the lower section of the control sleeve 18 to form a flushing chamber 18e of larger diameter. The rinsing chamber 18e is connected to the supply of rinsing liquid, not shown, via a radial feed opening 21.

A first metering piston 19 is slidably inserted into the axial through-bore 18d of the control sleeve 18, which has an annular cross-section and has at its upper end a piston section 19a which fits tightly in the axial through-bore 18d of the control sleeve 18. The dimensions of the first metering piston 19 are reduced below the piston section 19a. The metering piston 19 penetrates at the lower end of the control sleeve 18 at a bore 18f and is guided through this.

In the first metering piston 19, a central axial bore 19b of constant cross section is formed, in which a second metering piston 20 is slidably arranged. The second metering piston 20 has an upper piston section 20a, which fits tightly and seals in the axial bore

19b of the first metering piston 19 is seated. At the lower end of the piston section 20a of the second metering piston 20 there is a piston rod section 20b, which penetrates and is guided through a lower guide and cover plate 22 of the first metering piston 19 in a sealing manner.

The axial bore 19b of the first metering piston 19 has a feed opening 23 at its lower end, which is also connected to the supply of flushing liquid. The first metering piston 19 can either be moved together with the second metering piston 20 as a unit in the axial bore 18d of the control sleeve 18, but it is also possible to adjust each of the metering pistons 19 and 20 independently of the other metering piston.

The mode of operation of the metering device and its possible operating modes are to be explained by way of example:

1 and 2 show the starting position of a metering process. The two metering pistons 19 and 20 with their piston sections 19a and 20a are each in an upper end position and the control sleeve 18 is set within the housing 11 such that the inlet opening 14 is connected to the metering chamber 13 via the axial groove 18b. The connection between the metering chamber 13 and the outlet opening 15 is interrupted. Starting from this position, the two metering pistons 19 and 20 are adjusted downwards as a unit within the axial bore 18d of the control sleeve 18, as a result of which the volume of the metering chamber 13 is increased (see FIG. 3). The resulting vacuum draws the filling medium through the inlet opening 14 and the axial groove 18b into the metering chamber 13. When the metering pistons 19 and 20 have reached their lower end position, the control sleeve 18 is rotated through 45 °, as a result of which the connection between the inlet opening is set to 14 and the Dosierkam ^¬ mer 13 is interrupted and, instead, a communication between the metering chamber 13 and the outlet port 15 manufacturer (see Fig. 6). Then, the two dosing pistons 19 and 20 are moved upward together, whereby the volume of the metering chamber 13 is reduced again, with the result that the filling medium is forced out from the Dosierkam ^¬ mer 13 via the axial groove 18c through the outlet port 15 °. The resulting increase in pressure Within the metering chamber 13 also acts on the control sleeve 18 and presses it downward, so that the conical section 18a of the control sleeve 18 is pressed against the conical section 12 of the axial bore 12 of the housing 11, whereby the sealing effect is enhanced. At the end of the stroke of the metering pistons 19 and 20, these are again in their upper end position (see FIG. 5), as a result of which the conveying process is ended. The control sleeve 18 is then rotated again by 45 ° in the opposite direction, so that the starting position according to FIG. 1 is reached again, from which a new dosing process can be started.

If the amount of filling medium metered by the two metering pistons 19 and 20 is too large, the metering pistons 19 and 20 can also be adjusted independently of one another. A first example of this is shown in FIG. 7. Starting from the starting position according to FIG. 1, in which the metering chamber 13 is connected to the inlet opening 14 via the axial groove 18b, not both metering pistons 19 and 20 are now adjusted, but the inner second metering piston 20 remains and only the annular outer first metering piston 19 is adjusted downward, so that even the medium is sucked through the inlet opening 14 and the axial groove 18b into the metering chamber 13, but the volume increase of the metering chamber 13 is less, so that the amount of filling medium sucked in is also reduced.

By turning the control sleeve 18 and returning the outer annular first metering piston 19 to the starting position, the filling medium located in the metering chamber 13 can be pressed out through the axial groove 18c and the outlet opening 19.

8 shows an alternative mode of operation in which the outer, ring-shaped first metering piston 19 stops while rend only the inner second metering piston 20 is adjusted downwards for sucking the filling medium into the metering chamber 13. The resulting increase in volume of the metering chamber 13 is even less than in the previously explained example, in which only the outer first metering piston 19 is adjusted, so that an even smaller amount of filling medium is metered. Here too, after the control sleeve 18 has been rotated, the filling medium is pressed out of the metering chamber 13 in that the second metering piston 20 is returned to its upper starting position.

When changing the filling medium to be metered, the metering device 10 must be cleaned. For this purpose, the components can be moved into a so-called cleaning position, which is shown in FIG. 9. On the one hand, the outer first metering piston 19 is moved downward within the axial through bore 18d of the control sleeve 18 to such an extent that its piston section 19a is freely arranged in the rinsing chamber 18e of the control sleeve 18. The piston section 20a of the inner second metering piston 20 protrudes completely upward from the axial bore 19b of the first metering piston 19 and lies freely within the axial through-bore 18d of the control sleeve 18. This is turned upward a small amount relative to the housing 11. pushed, whereby its conical section 18a is released from contact with the conical section 12a of the axial bore 12 of the housing 11. Cleaning or rinsing liquid is introduced into the rinsing chamber 18e through the feed opening 21, as indicated by the arrow CI, which rinses the piston section 19a of the outer first metering piston 19 and thereby cleans it. In addition, cleaning or rinsing liquid is introduced through the feed opening 23 into the axial bore 19b of the first metering piston 19, as indicated by the arrow C2, which flows through the axial bore 19b and exits at the upper end and then the around exposed piston section 20a of inner second metering piston 20.

Due to the axial adjustment of the control sleeve 18 relative to the housing 11 is between the conical. Section 12a of the axial bore 12 of the housing 11 and the conical section 18a of the control sleeve 18 form an annular gap which is connected at its lower end to the opening 11a through which the cleaning or rinsing liquid is introduced, as shown by the arrow C3 is. In addition, cleaning and rinsing liquid can also be introduced through the inlet opening 14 (arrow C4). The cleaning and rinsing liquid introduced in the aforementioned manner can be discharged, for example, through the outlet opening 15, as indicated by the arrow C5.

After completion of the cleaning operation, the outer he ^¬ ste metering piston 19 moved within the control sleeve 18 upwards, arranged to be sealingly under piston section 19a ene ger fit in the axial passage hole 18d of the control sleeve 18th An adjustment of the control sleeve 18 in the axial direction again brings the two conical sections 12a and 18a into sealing contact, so that the starting position shown in FIG. 1 is then reached again.

Claims

claims

1. Dosing device in a tube filling machine, with a dosing chamber (13) formed in a housing (11), which has an inlet opening (14) and an outlet opening (15) for a medium to be dosed, at least one adjustable dosing piston (19, 20 ), by means of which the volume of the metering chamber (13) can be changed, and a control sleeve (18) rotatably mounted in the housing (11), which has at least one connecting channel (18b, 18c) which is in a predetermined rotational position of the control sleeve (18 ) connects the inlet opening (14) or the outlet opening (15) to the metering chamber (13), the control sleeve (18) having a conical section (18a) which is connected to a complementary conical section (12a) of the housing (11) Can be applied in a sealing manner and lifted off from it, characterized in that the control sleeve (18) has an axial through-bore (18d) in which the at least one metering piston (19, 20) is displaceably guided, and in that at least t a section of the metering chamber (13) is formed on the side facing the wider end of the conical section (18a) of the control sleeve (18). Det, the conical sections (12a, 18a) can be clamped against each other when the pressure in the metering chamber (13) increases due to a movement of the metering piston (19, 20).

2. Dosing device according to claim 1, characterized in that two coaxial dosing pistons (19, 20) are provided, of which a first dosing piston (19) as an annular piston with an axial bore guided in the axial through bore (18d) of the control sleeve (18) (19b) is formed, in which a second metering piston (20) is displaceably guided.

3. Metering device according to claim 2, characterized in that the two metering pistons (19, 20) are adjustable as a unit or independently of one another.

4. Metering device according to claim 2 or 3, characterized in that each metering piston (19, 20) is assigned its own drive in the form of a servo motor.

5. Dosing device according to one of claims 1 to 4, characterized in that in the axial through bore (18d) of the control sleeve (18) a flushing chamber (18e) of enlarged diameter is formed, in which a piston section (19a) of the first dosing piston ( 19) is receivable with clearance and in that the Spülkam ^¬ mer (18e) via at least one supply opening (21) is fed to a rinsing liquid.

6. Dosing device according to one of claims 1 to 5, characterized in that in a raised conical section (18a) between the housing (11) and the control sleeve (18) formed space via at least one feed opening (11a) of the housing (11) a rinsing liquid can be introduced.

7. Metering device according to one of claims 1 to 6, characterized in that the housing (11) and / or the control sleeve (18) and / or the metering piston (19, 20) consist of a ceramic material.

8. Dosing device according to one of claims 1 to 7, characterized in that the connecting channel is formed by an axial groove (18b, 18c).

9. Dosing device according to claim 8, characterized in that at least two axial grooves (18b, 18c) are provided, by means of which the inlet opening (14) or the outlet opening (15) can be connected to the dosing chamber (13).

10. Dosing device according to claim 8 or 9, characterized in that the axial grooves (18b, 18c) are formed in the conical section (18a) of the control sleeve (18).