CA2076173A1

CA2076173A1 - Process and a device for the filling of vessels

Info

Publication number: CA2076173A1
Application number: CA002076173A
Authority: CA
Inventors: Wilhelm Weiss
Original assignee: Krones AG Hermann Kronseder Maschinenfabrik
Current assignee: Krones AG
Priority date: 1991-08-16
Filing date: 1992-08-14
Publication date: 1993-02-17
Also published as: KR930004188A; JPH05193700A; EP0528216A1; DE4127052A1; BR9203163A

Abstract

Abstract The invention relates to a process for the filling of a vessel with a liquid and a device for carrying out the process, the liquid being supplied to the vessel via a liquid feed line, the reaching of a predetermined filling level in the vessel is measured by at least one probe and the supply of liquid is stopped after the response of one of the probes. The accuracy of the final filling level is to be improved in simple fashion with the process according to the invention and the associated device. For this purpose, liquid is again supplied after a predetermined waiting time until one of the probes responds again, and then the supply of liquid is stopped again.

Description

- 1 - 2~7~

A Process and a Device for the Filling of Vessels Specification The invention relates to a process for the filling of a vessel, which has the fe,atures of the preamble o~ claim 1 and a device ~or carrying out the process, which has the features of the preamble of claim 7.

Such a process and such a device are known from DE-OS
32 ~5 731. Liquid is filled there into a vessel under counter-pressure. In order to avoid that the liquids get into the return gas section, probes are disposed below the return gas line/ which stop the supply o~
uid via a valve. Thus, the filling process is stopped shortly before the reaching of the opening of the return gas line. If the liquid or the foam produced by the filling reaches the first probe, the supply of liquid is reduced by means of a throttling means so that the filling process is continued at reduced speed.
If the liquid or the foam reaches the upper probe, the valve is closed and the supply of liguid is s~opped.

The process forming the genus and a device for carrying out this pxocess are also known from US-PS 3 918 475.
The device has a long filling ~ube with two valves ~or a rapid and a slow supply o~ liquid. The filling tube is provided with two probes. ~or terminating the ~illing pro~ess taking place at atmospheric pressure the valve controlling the rapid ~low is closed via a first prob~ when the liquid or the foam reaches a ~irst h~ f ; ';~

filling level and then, the valve controlling the slow flow i~ closed upon the reaching of the second probe.

The known processes and devices are not suited for filling open vessels with liquids tending to form foam, in particular not in the case of the use of short filling tubes, since the desixed final filling level of the liquid can only he precletermilled inaccurately upon the ~topping of the fillin~ process. I~ liquids such a~, water are fi:LlPd, ambient air gets in~.o the vessel at the same time with the liquid. Due to this a foam and bubble formakion occurs du.ring the filling process to which the probes respond although th~ liquid level has not reached the final filling level a~ yet. The extenk of the error depends on the size of tha foam and bubble formation, which is of differing siza for dif~erent liquids. This error makes itself felt quite clearly in the case of specific water~. A similar effect can al80 occur during filling under counter-pressure.

In view of this prior art, the invention is based on the object of creating a process for the f;lling o~ a vessel and a device for carrying out this process, with which the accuracy of the final filling level is improved in simple fashion.

~his object is attained according to the invention by a process with the features of claim 1 and a device with the features of claim 7.

Due to tha waiting time after the stopping of the first supply o~ liquid it is achieved that the foam which was formed on the surface of the liquid during the supply of the liquid is decomposed again. Due to this, a smooth surface of the liquid is formed which i5 located below the first probe. Since, after this waiting time, liquid is supplied again, until one of the probes responds again and the supply o~ liquid is then stopped, the vessel can be filled to the desired ~inal filling level with greal acuracy. Since the second .filling process is only very short, no new ~oam is formed on the sur~ace of the liquid so that the final filling level is achieved by the ~act that the liquid itself and not the foam causes the second responds of one of the probes. Thus, the desired final ~illinq level is precisely reachecl.

According to an advantageous further development oP the invention, the supply of liquid is immediately inter-rupted upon the first response of the probe. This simplifies thè control of the device, since a reduction of the flow of liquid and the device necessary ~or this, are then not required.

A further simplification of the device can be ~chieved by the fact that only one probe is used for measuring the filling level. The supply of liquid is then stopped for the first time upon the response of the probe due to the foam on the surface of the liquid. The same probe responds the second time, if, after the waiting time, during which the Poam is decomposed, liquid is again supplied and the surface of the liquid which is now ~ree from foam reaches the pro~e again.

It may also be advantageous if two probes are provided, the second probe being disposed above the first probe.
The distance of the two probes can be adapted to the filling conditions here. This is in particular oP
advantage in the case o~ a rapid supply of liquid or not too great a foam formation of the liquid.

~J ~ 7 It is furthermore advantageous i~ the probes are disposed on the outer side of the filling tube. The height of the probes can then be controlled in an especially simple fashion b~ the immersion depth o~ the filling tube into the vessel. Moreover, the probes are easily accessible for control and repair. It is also advantageous if t}le probes have a metal core connected to a voltage source, whlich is insulated from the filli.ng tube by an insulat,ing casing~ These probes can be di.sposed in simple fashion on the filling tube, have a high measuriny accuracy and a rapid response time.

It is also advantacJeous if the probes are surrounded by a protectiny tube, which only spares the lower ends of the probes. Since then the probes are prokected against detrimental influences of the ~nvironment, e.g, scratching by being pushed ag~inst somethinq or soiling due to liquids or air. The free ends define the response points which react to the rising liquid or the foam formed thereon. ThP casing surface o~ the ~illing tube may advantageously ha~e recesses into which the probes are inserted in such fashion that the outer surface o~ the probes is substantially in alignment with the casing surface of the ~illing tube. It is achieved due to this that the probes do not project beyond the casing surface of the ~illing tube, and damage to the probes is thus avoided.

It is furthermore advantageous if the valve is disposed in the filling tube. Thus the amount of liquid still located in the filling tube upon the closing of the valve can be kept small. It is also of advantage if the filling tube has a reduced inner diameter below tha opening of the liquid feed line, the transition area to the reduced inner diameter forming an edg~less valve r~ ~

seat on which the valve rests sealingly in closed condition. Due to the continuous transition it i6 made possible in simple fashion that the valve can adopt various open positions, in which a differenk thxough-flow of liquid can be controlled by the differing distance of the valve fro~ the filling tube wall.

~ccording to an advantageous further development o~ the invention, a pneumatic actuator connected to the control means i5 provided for the opening and closing of the valve. A pneumatic cylinder is customarily used.
Thus, a simple, reliably controllable opening and closing of the valve is made po~sible. The pneumatic actuator is advantageously designed as a multi-posikion cylinder. Due to dif~erent positions of the multi-position cylinder different Plows of liquid can then be achiev~d. A smaller flow o~ liquid can then in parti-cular be selected in the second supply of liquid so that a still more precise stopping at the desired final filling level can take place.

According to an advantagaou~ urther development of the invention, a protective gas line is provided which leads into a protective gas sleeve surrounding the ~illing tube above the vessel to be filled. This is of special advantage i~ the filling tube is introduced into the vessel without contact and sealing in order to avoid a contamination of the opening of the vessel. A
protective gas can be supplied to the vessel in the area of its opening during the filling process so that the vessel is protected against the penetration of ambient air into its opening during the entire filling process. Moreover, protective ~as line and protective gas sleeve can be used for cleaning the filling tube from the outside and to sterilize it, e.g. by the ' 3 ~ 6 introduction of water, hot water, vapour, etc., during the time during which no vessel is filled.

The invenkion is explained in qreater detail by means of the drawings in the following.

Fig. 1 shows a cross-section through a first example of embodiment of the device according to the invention and Fiy. 2 shows a cross-section through a second example of embodiment of the device according to the invention.

Fig. 1 shows an example of embodiment of a filling device 1 in cross-section, below whi~h a vessel 2 is disposed in the form o~ a bottle to be filled with a liquid, e.g. mineral water. The filling device comprises a filling tube 3 whose lower end project.s into the openiny 4 of the vessel 20 A liquid feed line 5 opens into the filling tube 3. The ~illing tube 3 has a reduced inner diameter below the opening of the liquid feed line. The transition area in the filling tube to the end with the reduced inner diameter forms an edgeless valve seat 6, on which a valve 7 rests sealingly in closed condition so that th~ flow of liquid through the filling tube 3 is interrupted. A
pneumatic cylin~er 8 is disposed for controlling the valve 7, which opens and closes ~he valve 7 via the pressure line 90 The pneumatic cylinder 8 can be designed as a multi~position cylinder so that different opening positions o the valve 7 are possible, in which dif~erently large ~lows of liquid can be flow into the vessel 2 through the filling tube 3.

At the low~r end of the filling tube 3 which projects into the vessel 2; a recess 10 is formed in the casing r~ 3 surface of the ~illing tube 3 into which a probe 11 is inserted. The probe 11 comprises a metal core 12 and an insulating casing 13 connected to a control means 17 by means of a line 23 and is disposed in such ~ashi~n in the recess 10 that its surface is substantially in alignment with the casing surface o~ the filling tube 3. For the further protection of the probe 11 it is surrounded by a protecting tube 14 which only leaves the lower end 15 o~ the probe ll uncovered. Due to this, the prohe 11 is completely protected against soiling and the response point of the probe 11 is exactly defined. :

In the following the process :is described by means o~
the operation of the device according to Fig. 1. The vessel 2 is filled with l~iquid through the filling tube 3, until the foam formed during filling reaches the lower end 15 of the probe 11. A signal is supplied to the control means 17 via the probe 11, due to which th~
pneumatic cyllnder i~ ~ctuated vla the pre~sure lin~ g so that the filling proaes~ i~ terminated b~ alo5ing the valve 7.

Due to this, the sur~ace o~ the liquid i~ located below the lower end 15 of the probe 11. After a predetermined waiting time of e.~. one second, within which the ~oam is decomposed, the filling process is started ayain by opening the valve. This second filling process is then stopped again, when the liquid reaches the lower snd 15 of the probe 11 for the second time. The signal is transmitted to the control means 17 via the probe 11, which actuates the pneumatic cylinder 8 and thus closes the valve 7. Since, due to the short duration, ~o ~oam is formed during the second filling proces~, the level ;J ~

of tha surface o~ the liquid now corresponds to the height of th~ response point 15 of the probe 11.

Fig. 2 shows a second example o~ embodiment of the device according to the invention. The parts of the device designated with the same reference numerals correspond to those o~ ~ig. 1 and comply with the functioning described in this connection inasmuch as nothing else is explained in the ~ollowing.

Thus, only the differences with respect to the first example of embodiment are described in the following.
In addition to the recess lO in the casi.ng sur~ace o~
the lower end oP the filling tube 3 into which the probe is inserted, a recess 10' is pro~ided in the casing surface, into which the second probe 11' is inserted. The probe 11' comprises a m~tal core 12' conn~cted to the control means 17, which is insulated from the ~illing tube 3 by an insulating casing 13'.
The surface of the probe 11' is furthermore substan-tially in alignment with the casing surface of the filling tube 3~ The probe 11' is surrounded by the protecting tube 14 as is the probe 11. The protecting tube 14 has a second interruption which leaves the lower end l9 of the probe 11' ~ree and thus defines the second response point.

During the filling process, the lower end 15 o~ the probe 11 responds to the rising surface of the li~uid or its foam, whereby the valve 7 is closed via tha control means 17, the pressure line 9 and the pneumatic cylinder 8. During a predetermined waiting time, tha ~oam settles on the sur~ace of the liquid so that it is below the lower end 15 of the probe 11. After the predetarmined waiting time during which the foam has 7~ 7 ~

settled the filling process begins again as it was already described in connection with Fig. '. As opposed to the example of embodiment of Fig. 1, the f illing process, however, i5 only stopped when the surface of the liquid which increases again has reached the lower end 19 of the second probe 11'. A signal is tran~mitted to the control means 17 via the probe 11', which then closes the valve 7 via the pneumatic cylinder 8 and the pressure line 9. Since during the second, only very short ~illing process no further bubbles or foam are formed, the level o~ the surface of the liquid corresponds exactly to the height of the lower end lg of the probe 11', by means of which the predetermined filling level is defined.

The device 1 is furthermore mounted on a supporting plate 20 in this example o~ embodiment. The supporting plat~ 20 can be designed as a rotating plate and receive several ~illing devices so that sPveral vessels 2 can be filled at the same time. For this, the support of the vessel 2 is vertically movable so that the filling tube 3 can be guided out of the v~ssel 2 and positioned again in the next vessel 2 at the desixed height.

The filling deYice 1 comprises furthermore a protectiY~.
gas feed line 21, which opens into a protective gas sleeve 33 surrounding the ~illing tube 3 above the vessel 2 to be filled. The opening 4 of the vessel 2 can be prote~ted against contamination during the ~illing process by the supply o~ protective gas via ~he protective gas line 21 and the protective gas sleeve 22. Moreover, the filling tube can be cleaned at the out~ide via the protective gas line 21 and the pro-tective g,as sleeve 22 by means of the introduction of 7; ~

water, hot water, vapour, etc., if no ~essels 2 are filled.

The process according to the invention is described by means of Fig. 2 in the following. A vessel 2 is fed to the ~illing device 1 disposed on the supporting plate 20 and positioned at a predetermined suited height with respect to the filling tllbe 3. This height is selected in such fashion that the lower end 19 of the second probe 11' comes to rest in such fashion with respect to the vessel 2 that the desir~d final height is to be present there. The valve 7 is opened via the cont,rol means 17, the pressure line 9 and the pneumatic cylin~
ner 8 so that the liquid to be filled, e.g. water, gets into the lower end o~ the filling tube 3 and thus into the vessel 2 via the liquid ~eed line 5 through the gap formed between the valve 7 and thQ valve seat 6. The liquid rises in the vessel 2 until the liquid or the foam on the surface of the liquid reaches the lower end 15 of the probe 11 . The probe 11 which responds to the liquid or the foam on the surface of the liquid trans-mits a signal to the control mean~ 17 which closes the valve 7 via the pressure line 9 and the pneumatic cylinder 8. The supply of liquid from the liquid feed line 5 into the vessel 2 is thus interrupted. Due to the ~illing process via the short filling tube 3 into the open opening 4 of the ves~el 2 that much air ha~
gotten into the vessel 2 with the liquid or the water that the surface o~ the liquid consists of foam and bubbles. During a waiting time aftar the stopping of the filling process, foam and bubbles are decomposed on th surfac~ of the liquid so that the surface o~ the liquid is below the lower end 15 of the probe 11. After the waiting time which is sufficient for the decomposi-tion of the foam on the surface of th~ liquid, the ~,~'7~3~

valve 7 is opened automatically again by the control means 17 via khe pressur,e line 9 and the pneumatic cylinder 8. The opening of the valve 7 is either effected in the original position duriny the preceding filling process or in an intermediate position, in which the passage between the valve 7 and the valve seat 6 is smaller than during the first filling pro-cess. The refilling process is stoppecl when the lower end 19 o~ the second probe 11' re~ponds to the surface of the li~uid which rises again. Then the valve 7 i5 clo~ed again by the control means 17 via the pressure line 9 and the pneumatic cyl.inder 8. Si.nce the refill~
ing process is only very short, thers is no renewed foam and bubble formation on the surface of the liquid so that the level of the surface of the liquid corres-ponds exactly to the predetPrmined filling level which is determined by the lower end 19 of the probe 11l. ThP
filling tub 3 is removed ~rom the opening 4 of the vessel 2 by a lowering of the vessel 2 or a lifting of the filling device 1. Then the vessel 2 is guided ~o the closing station, and a further vessel 2 is brought into the filling position so that the filling proces~
described above can hegin anew.

Claims

1) A process for the filling of a vessel with a liquid, in which the liquid is supplied to the vessel via a liquid feed line, the reaching of a predetermined filling level in the vessel is measured by means of at least one probe and the supply of liquid is stopped after the response of one of the probes, characterized in that, after a predetermined waiting time, liquid is supplied again until one of the probes (11, 11') responds again and that, thereafter, the supply of liquid is stopped again.

2. A process according to claim 1, characterized in that the supply of liquid is interrupted immediately upon the first response of the probe (11).

3. A process according to claim 1 or 2, characterized in that only one probe (11) is used for the first and second stopping of the supply of liquid.

4. A process according to claim 1 or 2, characterized in that two probes (11, 11') disposed at different heights are used, the supply of liquid being stopped for the first time upon the response of the lower probe (11) and the second time upon the response of the upper probe (11').

5. A process according to any of claims 1 to 4, char-acterized in that the renewed supply of liquid is effected at a reduced flow of liquid as compared with the first supply of liquid.

6. A process according to any of claims 1 to 5, char-acterized in that protective gas is supplied to the vessel (2) in the area of its opening (4) during the filling process.

7. A device for filling a vessel with a liquid com-prising a filling tube, with liquid feed line connected thereto, a controllable valve for interrupting the flow of liquid in the filling tube, at least one probe for measuring the liquid level in the vessel to be filled and a control means for closing the valve if one of the probes responds, characterized in that the control means (17) is designed in such fashion that, after the closing of the valve (7), it is automatically opened after a predetermined waiting time and is closed again upon the second response of one of the process (11, 11').

8. A device according to claim 7, characterized in that the control means (17) is of such a design that the valve (7) is closed immediately upon the first response of the probe (11).

9) A device according to claim 7 or 8, characterized in that only one probe (11) is provided.

10. A device according to claim 7 or 8 characterized in that two probes (11, 11') are provided, the second probe (11') being disposed above the first probe (11).

11. A device according to any of claims 7 to 10, characterized in that the probes (11, 11') are disposed on the outer side of the filling tube (3).

12. A device according to any of claims 7 to 11, characterized in that the probes (11, 11') have a metal core (12, 12') connected to a voltage source, which is insulated by an insulating casing (13, 13') from the filling tube (3).

13. A device according to any of claims 7 to 12, characterized in that the probes (11, 11') are sur-rounded by a protective tube (14), which only spares the lower ends of the probes (11, 11').

14. A device according to any of claims 7 to 13, characterized in that the casing surface of the filling tube (3) has recesses (10, 10'), into which the probes (11, 11') are inserted in such fashion that the outer surface of the probes (11, 11') is substantially in alignment with the casing surface of the filling tube (3).

15. A device according to any of claims 7 to 14, characterized in that the valve (7) is disposed in the filling tube (3).

16. A device according to any of claims 7 to 15, characterized in that the filling tube (3) has a reduced inner diameter below the opening of the liquid feed line (5), the transition area to the reduced inner diameter forming an edgeless valve seat, on which the valve (7) rests sealingly in closed condition.

17. A device according to any of claims 7 to 16, characterized in that a pneumatic actuator (8) is connected to the control means (17) for opening and closing the valve (7).

18. A device according to claim 17, characterized in that the pneumatic actuator (8) is designed as a multi-position cylinder.

19. A device according to any of claims 7 to 18, characterized in that a protective gas feed line (21) is provided which opens into a protective gas sleeve (22) surrounding the filling tube (3) above the vessel (2) to be filled.