Filling apparatus

Abstract

A filling device includes an evaluation device that is connected by a data line to pressure sensor and that detects an opening pressure of a keg or of a keg fitting, compares it with stored reference pressure data, and chooses, based on the result of the comparison, between allowing the keg to be filled and preventing the keg from being filled.

Claims

1. An apparatus for filling a keg, said apparatus comprising a filling element, wherein said filling element comprises a filling pipe comprising a free pipe-end for engaging a keg fitting of said keg, a plunger that is arranged in said filling pipe and that is movable along an axial direction to interact with a retention spring of said keg fitting so as to open said keg, an actuator that causes axial movement of said plunger, and a pressurized region, said pressurized region comprising a pressure-delivery line and a pressure chamber, wherein said actuator comprises a piston, a cylinder, and said pressure chamber, wherein said piston connects to or forms said plunger, a control valve that connects said pressurized region to a pressure source that provides pressure for moving said piston towards said free pipe-end and towards said keg fitting, a pressure sensor for sensing an actuation pressure in said pressure chamber, and an evaluation device that is connected by a data line to said pressure sensor, said evaluation device being configured to detect, in said pressurized region, an opening pressure of a keg or of a keg fitting, to compare said opening pressure with stored reference pressure data, thereby generating a comparison, and to choose, based on said comparison, between allowing said keg to be filled and preventing said keg from being filled, wherein said evaluation device is further configured to detect said opening pressure by detecting a pressure peak.

2. The apparatus of claim 1, further comprising a controller that is configured to interrupt said filling process as a function of said comparison.

3. The apparatus of claim 1, wherein said evaluation device is configured to permit said keg to be filled based upon having determined that said opening pressure lies above a lower reference pressure and below an upper reference pressure.

4. The apparatus of claim 1, wherein said evaluation device is configured so as to evaluate a time curve of said actuating pressure and to interpret a pressure maximum on said time curve as an opening pressure.

5. The apparatus of claim 1, further comprising a position sensor for at least one position of said plunger, wherein said evaluation device is configured to evaluate a signal from said position sensor for detection of said opening pressure.

6. The apparatus of claim 1, wherein said evaluation device is further configured to determine that said actuating pressure is lower than said reference pressure.

7. The apparatus of claim 1, wherein said evaluation device is further configured to compare said opening pressure with a stored upper reference pressure and to determine that said upper reference pressure has been exceeded.

8. The apparatus of claim 1, wherein said evaluation device is further configured to detect said opening pressure of said keg fitting by detecting a position of said plunger.

9. The apparatus of claim 1, wherein said evaluation device is further configured to detect said opening pressure of said keg fitting by detecting a position of a part of said filling device that moves with said plunger.

10. The apparatus of claim 1, wherein said piston forms said plunger.

11. The apparatus of claim 1, wherein said piston is connected to said plunger.

12. The apparatus of claim 1, further comprising a lower pressure-chamber that connects to said pressure-delivery line via said control valve, wherein said cylinder comprises an inner wall, and wherein said piston comprises a plate-shaped extension having an outer circumference that seals said inner wall to form said lower pressure-chamber.

13. The apparatus of claim 1, further comprising an upper pressure-chamber that is connected to a pressure-discharge line for moving said piston to close said keg fitting, wherein said piston comprises a plate-shaped extension having an outer circumference that seals said cylinder's inner wall to form said upper pressure-chamber.

14. The apparatus of claim 1, wherein said evaluation device is further configured to detect that said keg is defective as a result of said keg fitting having opened at a minimum value of opening pressure.

15. The apparatus of claim 1, wherein said evaluation device is further configured to determine, based on said opening pressure, that said keg is a single-use keg.

16. The apparatus of claim 1, wherein said evaluation device is further configured to detect, based on said opening pressure, that said keg is a reusable keg.

17. The apparatus of claim 1, further comprising an upper flange at said free end.

18. The apparatus of claim 1, wherein said pressure is a time-varying quantity having a derivative having a sign and wherein said evaluation device is further configured to detect said opening pressure by detecting that said sign has changed from positive to negative.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is described hereinafter by way of example, on the basis of the schematic drawings. The drawings show:

(2) FIG. 1 A is a schematic view of a part of a filling apparatus,

(3) FIG. 2 shows pressure as a function of time during the filling of a keg, and

(4) FIG. 3 a shows permissible pressures for single-use kegs and reusable kegs.

DETAILED DESCRIPTION

(5) FIG. 1 shows a filling element 10 of a filling machine. The filling element 10 includes a filling pipe 12. Both a product-delivery element 16 and a pressurized-gas delivery element open into the filling pipe 12. These permit pressure filling of the keg. The filling pipe 12 of the filling element 10 is flanged to a keg by an upper flange 14 at the pipe's free end 12.1. The keg that is to be filled, as well as other transport, carrying, and treatment elements, have been omitted for clarity.

(6) Within the filling pipe 12, an actuator 21 moves a plunger 20 vertically along an axis. An actuator 21 comprises a piston 22 that moves through a hydraulic pressure cylinder.

(7) At its first end, the piston 22 has a plate-shaped extension 23. The outer circumference of the extension 23 seals against the pressure cylinder's inner wall using a seal.

(8) The extension 23 thus forms a lower pressure-chamber 26 in the pressure cylinder 24. The lower pressure-chamber 26 connects to a hydraulic pressure delivery line 28 via a control valve 30 that opens or closes based on instructions from a controller 34. The controller 34 thus controls communication of the lower pressure chamber 26 with a pressure source 32. The resulting control over pressure in the lower pressure-chamber 26 drives the piston 22, when then drives the plunger 20 so that it moves towards the free pipe end 12.1 or the flange 14 to thereby open the keg. These collectively form the plunger's actuating device 21.

(9) Formed between the upper side of the plate-shaped extension 23 of the piston 22 and the upper side of the hydraulic cylinder is an upper pressure chamber 37, which cannot be seen in FIG. 1 due to the high position of the extension 23. Into this there opens a pressure discharge line 38, which in turn is likewise connected, by means of a control valve, not represented, to a pressure fluid container, e.g. the pressure source 32, in order to move the piston 22 downwards, in order to close the keg fitting after the filling process.

(10) The controller 34 learns of the pressure within the lower pressure-chamber 26 from a pressure sensor 36 that connects to the pressure delivery line 28. Within the controller 34, evaluation circuitry 40 uses a pressure signal from the pressure sensor 36 to evaluate the actuating pressure over time in the lower pressure chamber 26.

(11) The controller 34 receives further information from a position sensor 42 on the filling element. The position sensor 42 provides a position signal that has information on the plunger's position. This position signal is likewise available to the evaluation circuitry 40.

(12) The filling process proceeds with the keg's keg fitting being pressed against the filling element 10 by a pressing device that presses against the keg's base. The control valve 30 than opens and pressurizes the lower pressure-chamber 36 via the line 28.

(13) FIG. 2 shows a typical signal provided by the pressure sensor 36 during a filling operation. The process begins at time zero with phase “I” in which pressure slowly rises until it reaches on opening pressure p.sub.o at time t0. Upon reaching the opening pressure p.sub.o, the force exerted by the pressurized air becomes sufficient to force a spring in the keg fitting to open the keg. This cases a sudden pressure drop at phase “II” that begins when pressure reaches a peak “P”.

(14) As gas continues to enter the keg during phase “III,” the pressure again begins to rise until it reaches a plateau at phase “IV”. Minor pressure fluctuations that may occur during phase “III” and phase “IV” have been omitted for clarity.

(15) At phase “V”, the filling process is drawn to a close by reducing the pressure. This permits movement of the piston way from the keg fitting and eventual closure of the path to the pressure source.

(16) The brief spike in pressure “P” alluded to earlier serves as a prominent marker of the time that the keg fitting opened. This provides information on the opening time and the opening pressure p.sub.o that was required. This opening pressure p.sub.o and the pressure spike P are now compared with reference pressure ranges. FIG. 3 shows two reference-pressure ranges “a)” and “b)”.

(17) FIG. 3 shows first reference-pressures “a)” that specifies four reference ranges: range “a”, range “b”, range “c”, and range “d.” Range “a” is a lower range of impermissible pressures extending from 0 bar to approximately 1.6 bar. Range “b” represents permissible pressures for single-use kegs. Range “b” extends from approximately 1.6 bar to 2.6 bar. Range “c” extends above range “b”. Pressures in range “c” are permissible for reusable kegs. This range extends from approximately 3 bar to 4.3 bar. Above range “c” is range “d”, which is an upper range of impermissible pressures.

(18) If the pressure sensor 36 detects an opening pressure P.sub.o within range “a”, evaluation circuitry 40 assumes that the keg fitting as a whole is defective because it opened too early and below a minimum value. In this case the filling process or following process is interrupted and the keg fitting is screened out as defective.

(19) The permissible reference pressure range “b” for single use kegs lies between a lower reference value R.sub.ue and an upper reference value R.sub.oe. If the opening pressure P.sub.o moves in this reference pressure range “b”, then it is assumed that this relates to a single-use keg. The upper reference pressure R.sub.oe for single-use kegs corresponds, in the example shown, to the lower reference pressure Rum for reusable kegs, which forms the lower limit for the permissible reference pressure range “c” for reusable kegs. Accordingly, a keg is identified as a reusable keg if the opening pressure lies between the lower reference pressure R.sub.um for reusable kegs and the upper reference pressure R.sub.om for reusable kegs.

(20) If the opening pressure lies above the upper reference pressure value R.sub.om for reusable kegs, or if the keg fitting does not open at all, it is then assumed that the keg is likewise defective. As a result, it is screened out of the filling process.

(21) It is therefore possible on the basis of the detection and evaluation of the opening pressure to differentiate both between defective kegs, such as those with worn-out keg fittings and keg fittings that will no longer open, as well as between single-use kegs and reusable kegs.

(22) FIG. 3 also shows second reference-pressures “b)” but with a gap between range (b) and range (c).

(23) The reference pressure ranges reproduced in FIG. 3b are essentially identical to those in FIG. 3a. The difference is a transitional range “e” separates the reference pressure ranges “b” and “c” for single use kegs and reusable kegs. As a result, the upper reference pressure P.sub.o for a single use keg is no longer identical to the lower reference pressure R.sub.um for reusable kegs.

(24) Such a definition of the reference pressure ranges allows for a significant variation in the differentiation between single-use kegs and reusable kegs. In this situation the assumption is that, if the keg fitting opens in the pressure transition range, a keg fitting closure of a reusable keg is present but has a spring that is too weak to be used with a reusable keg. The keg is thus deemed defective and not filled.

(25) Depending on the quality and/or safety considerations, the respective reference ranges can be defined as narrower or broader and can be provided accordingly on the control side.

(26) The invention is not limited to the exemplary embodiments described but can be varied within the scope of protection of the claims which follow.