CA2115930A1

CA2115930A1 - Method and apparatus for adjusting the filling level in filling machines for vessels

Info

Publication number: CA2115930A1
Application number: CA002115930A
Authority: CA
Inventors: Franz Haring
Original assignee: Individual
Current assignee: Krones AG
Priority date: 1992-06-19
Filing date: 1993-06-18
Publication date: 1994-01-06
Also published as: ES2113540T3; WO1994000377A1; EP0598892A1; BR9305553A; JPH07502719A; DE59308279D1; EP0598892B1

Abstract

Method and Apparatus for Adjusting the Filling Level in Filling Machines for Vessels Abstract The present invention relates to a method and an apparatus for adjusting the filling level in filling machines for vessels, wherein the filling level is measured with the aid of a probe immersed in the filling vessel and is adjusted in response to a signal from the probe.

To obtain information about the instantaneous filling level at any time, a continuous measuring signal which is substantially proportional to the filling level is produced by a probe. An elongated probe body is here immersed into the liquid of the vessel to be filled, with a plurality of measuring points being connected to an electronic evaluation means via a plurality of switching elements, and a ground contact projects into the vessel to be filled to the farthest degree.

A quasi-continuous signal curve can be implemented with this method through a plurality of measuring points, resulting in a time-dependent signal function S (t) from the gradient of which the filling speed can be derived at any time t.

Description

t~

211~930 Method and Apparatus for Adjusting the Filling Level in Filling Machines for Vessels ____________________________________________________ :~ ~:
~. - . -Description The present invention relates to a method according to the preamble of claim 1 and to an apparatus according to the preamble of claim 8.

When liquids are filled into vessels, such as bottles, a ~ ~
specific control of the filling operation i5 needed, in -particular the conclusion thereof, to prevent spilling or -undefined or irregular filling levels. The use of probes has already been known for this purpose.

In the methods and apparatuses according to German Patent ~ -Application DE 32 45 731 and US Patent Specification US 39 18 475, the measuring points which are arranged at different levels serve as electric contacts which throttle and finally stop the liquid supply when the respective filling level is reached. In addition, it is possible in the method outlined in German Patent Specification DE 32 18 ~`

062 to sense the time between the response from two different measuring points and to interfere with the actual or subsequent filling operations in a correcting manner with the value obtained in this way.

These known methods operate with a purely intermittent ~
registration of the filling level at specific measuring or ~ -contact points. This presents an essential disadvantage because a number of objectionable factors may influence said level during the filling operation, these factors being, e.g., temperature or pressure variations, different gas content of the liquid, different vessel volumes, etc.
Furthermore, the individual contact points are provide~ in the known probes in an entirely separated way at differerent points of a probe rod or a gas or filling pipe and must therefore be connected by a plurality of lines individually to the electronic evaluation means. This requires great manufacturing efforts and increases the vulnerability of the system. Uninterrupted monitoring of the instantaneous filling level is not possible with the known probes.

It is therefore the object of the present invention to improve the method of the above-mentioned type, in particular, with respect to accuracy and vulnerability and to create a space-savinq and reliable probe for performing the method.

This object is attained with the features of claim 1 with -~
respect to the method and with the features of claim 8 with respect to the apparatus. ;~

With the method of the invention, a more or less continuous signal curve is obtained, depending on the number of measuring points and/or the design of a measuring point, so that one obtains a time-dependent signal function from the absolute value of which it is possible to derive the ,~
::::

.

instantaneous filling level and from the gradient of which the respective filling speed. The signal curve can also be regarded as a step function, wherein reaching of a first step corresponds to a first filling level and reaching of a second step to a second filling level. The filling speed is determined on the basis of the time between these two results in the measuring signal. The measuring signal can, e.g., represent a voltage drop at electric switching elements or a capacitance value.

In the method of the invention, an exact and direct adjustment of the filling level by immediately stopping the liquid supply is possible when a preselected filling level is reached because information about the instantaneous filling level is available at any time. The filling level can be varied at any time, e.g., for adaptation to another type of vessel or for considering variations in specific liquid properties, etc., by changing the preselected filling level, e.g., by means of a threshold value in the electronic evaluation means. Correction values, such as refilling time or refilling speed, as well as threshold values for the actual and the subsequent filling operations can be gained from the determined filling speeds for further optimization.

Advantageous developments of the method of the invention are shown in claims 2 to 7.

An inventive probe may, e.g., comprise a plurality of separated contact points for the liquid, the points being connected to the electronic evaluation means through a plurality of ohmic resistors, capacitors, antiparallel-connected diodes or other electronic components or combinations thereof. The components may be arranged within the probe near the measuring points or they may form the measuring points themselves, so that only a few or only one line is required for supplying the measuring signal to the - \

.
4 211~930 .
electronic evaluation means. It is also possible to combine an infinite number of measuring points without separation into a single elongated contact field or to connect a plurality of contact points to a single, elongated resistor, capacitor, or the like.

The probes comprise either a separate, e.g. rod-shaped probe body which has arranged thereon the measuring points and the switching elements connecting the same, or these are mounted on the filling or gas pipes of filling units.
The ground contacts can directly be mounted on the probe body, too, or may be formed by the filling or gas pipes or also by the liquid. Corresponding developments of the invention are specified in claims 9 to 28. At any rate, this results in an extremely space-saving arrangement having only a few lines, which permits a reliable operation .
and a simple installation in filling units of filling machines.
~ :
A plurality of embodiments of the invention shall now be described in the following with reference to the drawings, wherein:
:
FIG.l is a partial section through a filling unit including an integrated probe; -:: :
FIG. 2 is an enlarged longitudinal section through a first embodiment of the probe:

FIG. 3 is an enlarged longitudinal section through a second embodiment of the probe;

FIG. 4 i8 an equivalent circuit diagram of the first embodiment of the probe;

FIG. 5 shows a typical probe-signal time curve of the the first embodiment of the probe; ;~

211~930 IG. 6 shows a typical probe-signal time curve of the second embodiment of the probe;
:~: ,: -IG. 7 is an enlarged longitudinal section through athird embodiment of the probe;
IG. 8 is an enlarged longitudinal section through a fourth embodiment of the probe;
. . .
FIGS. 9 ~ -and lO show an enlarged longitudinal section through a return gas pipe with integrated probe in two different embodiments;
IG. 11 is a longitudinal section through another embodiment of a probe;
I~.. 12 is a lateral view of the probe according to FIG.
11;
IG. 13 is a longitudinal section through another filling unit with integrated probe;
IG. 14 is a longitudinal section through another embodiment of a probe.

The filling unit according to FIG. 1 is part of a rotary counterpressure filling machine (not shown in more detail) for filling bottles 18 with a C02 containing beverage. It has a housing 9 whose lower end has formed thereon a filling nozzle 14. This filling nozzle is upwardly followed by a valve seat 16 which cooperates with a valve body 17 that is supported within housing 9 in a vertically movable way. Beverage outflow into bottle 18 is controlled by the liquid valve formed thereby. The lifting movement of the valve body 17 is accomplished through an actuating motor (not shown). A metallic return gas pipe 8 by which the ;
bottle 18 to be filled is acted upon with pressurizing gas in a conventional way and through which the pressurizing gas is discharged from the bottle during inflow of liquid is mounted within a hole of valve body 17. Furthermore, a - -vertically movably supported centering bell 13 is provided with a sealing ring 15 which ensures exact centering of the bottle opening during the introduction of the return gas pipe 8 into the interior of the bottle and also a tight seal between the bottle 18, which is pressed against the filling unit, and filling nozzle 14 during the filling operation.

A rod-shaped probe 4 is concentrically mounted inside the return gas pipe 8. Probe 4 is led upwards out of the return gas pipe 8 and is connected via a line 19 to an electronic ;~
evaluation means (not shown) that controls, inter alia, the actuating motor for valve body 17. Probe 4 projects downwards from the return gas pipe 8 in such a way that, when bottle 18 is pressed against the filling unit, it is immersed in the interior thereof. As soon as the level of the beverage flowing into bottle 18 has reached probe 4 during a filling operation, probe 4 continuously senses the actual values of the instantaneous filling level and passes the values to the electronic evaluation means. These values are, e.g., compared with set values and the sequence of the filling operation is controlled accordingly, e.g. by means of the liquid valve 16, 17 which is decisive for the filling level.

In the first embodiment of probe 4a as is illustrated in FIG. 2, the cylindrical probe body 10 thereof which consists of an insulating material, such as a plastic or ceramic material, has a plurality of superimposed measurinq points la, b, c, n formed of metallic contact zones.
Measuring points la to ln are connectad by three series-connected ohmic resistors 2 to each other and to line 19 ~ ~
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. . .

..... ~. ^ , `:
which extends through the interior of probe body 10. Thethree resistors 2 are disposed between the four measuring points; the uppermost measuring point ln is directly connected to line 19. When n is the number of measuring points, the number of resistors is thus n minus 1. A ground contact 3 which terminates at a point slightly lower than the lowermost measuring point la is provided at the side of probe 4a which is opposite to the measuring points la to ln. Ground contact 3 is connected via a line 20 to the metallic return gas pipe 8 and thus to valve housing 9 as ground.

The functional principle of probe 4a is illustrated in an equivalent circuit diagram of FIG. 4. A defined input voltage Ue is applied there via a voltage source 12 to the probe circuit and lines 19 and 20, with three ohmic resistors 2 (R1, R2, R3) being series-connected. During the filling operation the liquid level successively reaches the measuring points la, lb , lc, ln, thereby establishing ground connections at the respective measuring points. As illustrated in connection with FIG. 2, the output voltage Ua which drops at the ohmic resistors 2 (in FIG. 4: R1 and R2) changes in response to the filling level. Output voltage Ua is measured and processed in the electronic evaluation means.

The continuous curve of the measuring signal which is shown in FIG. 5 with a virtually proportional portion in the area of measuring points la to ln is obtained by successively arranging a plurality n of measuring points with a plurality n minus 1 of resistors 2. This results in a time-dependent signal function S (t), the steps of which become continuously smaller with an increasing number n so that in the end one can talk about a continuous, strictly monotonous signal curve. Since the signal difference ~S
is proportional to the height difference ~ H, it is 8 2~1~930 possible to determine the filling speed from the gradient of the straight line ~ S to a T.

In the second embodiment of probe 4b, which is illustrated in FIG. 3, a plurality of antiparallel-connected diodes 7 are disposed between two superimposed measuring points 5 and 6. The resultant circuit is connected via an ohmic -resistor 2 to line 19 for the probe signal. In this case, too, an input voltage Ue is applied, preferably an alternating voltage or an interrupted direct voltage. The resultant signal function S (t) is shown in FIG. 6. It has a stepped fundamental shape. The shape, however, is softened by the effect of diodes 7 to such an extent that one obtains a continuous, monotonous curve, i.e., a single definite voltage value is assigned to each instantaneous filling level. Moreover, reaching of the first step corresponds to a defined first filling level, reaching of the second step to a defined second filling level. The filling speed is determined on the basis of time difference ~ t between these two results through the relation of ~ H
to ~ t.

The filling level may also be measured in a purely capacitive manner, the reciprocal total capacitance following, e.g., from the sum of the reciprocal individual capacitances in response to the filling level.

The signals supplied by probe 4a or 4b are processed in an electronic evaluation means, and filling levels, filling speeds and refilling times can, e.g., be determined accordingly. Moreover, a direct exact adjustment of the filling level is possible by setting desired threshold values and by immediately closing liguid valve 16, 17, which closing operation is initiated by the setting operation.

- ~ ~

. . .

In the third embodiment of probe 4c as is shown in FIG. 7, the superimpsoed measuring points la to ln are directly formed by an elongated resistor 11 in the form of a rotational body provided with annular grooves 21. The annular grooves 21 are filled with an insulating material for separating the contact points. Resistor 11 is directly connected to line 19 for the probe signal at the upper end.
The electrical effect of probe 4c is similar to that of probe 4a.

In the fourth embodiment of probe 4d as is illustrated in FIG. 8, an infinite number of measuring points la to ln and of series-connected resistors are jointly implemented by a single cylindrical resistor body 22. The body is connected at its upper end to line 19 for the probe signal and has an effect similar to that of probe 4a of FIG. 2, but with an infinite number of measuring points la to ln.

In probes 4c and 4d as illustrated in FIGS. 7 and 8, there is no ground contact. The ground is here formed either directly by the liquid to be bottled or by the metallic return gas pipe 8 (not shown).

In the embodiment illustrated in FIG. 9, there is no rod-shaped probe body as with embodiments 4a to 4d. Instead of this, contact points la to ln which are directly formed by the surfaces of ohmic resistors 2 are superimposed on a downwardly projecting, tongue-shaped attachment 23 of the return gas pipe 8. Resistors 2 are embedded in a strip 25 of insulating material and conductively connected to one another. The uppermost resistor 2 and the uppermost measuring point ln, respectively, are connected to line 19 for the probe signal, the line being guided in insulated fashion upwards inside return gas pipe 8. The ground contact is formed by another attachment 24 of the metallic return gas pipe 8, which attachment 24 projects downwards in tongue-like fashion. The function of the fifth ,:

,j. . .

~.~
211~930 embodiment of probe 4e corresponds again substantially to the first embodiment 4a of FIG. 2.

The sixth embodiment of probe 4f as is shown in FIG. 10 differs from probe 4e according to FIG. 9 by the feature that a conductor strip 26 which is insulated on all sides is respectively mounted in a vertical position on the two downwardly projecting tongues 23, 24 of the return gas pipe 8. The two parallel conductor strips 26 thereby form a capacitor which is connected to the electronic evaluation means by one or two lines 19. The capacitance of capacitor 26 depends directly on the level of the beverage within the area of tongues 23, 24. In this case, too, an infinite number of measuring points la to ln are provided for, resulting in an exactly proportional curve of the measuring signal which is indicative of capacitance.

In probe 4d of FIG. 8, resistor 22 which has a cylindrical outer contact surface may, e.g., consist of metal. Another suitable material is plastics with embedded graphite particles, i.e. an electrically conductive plastic material. The desired resistance characteristics of e.g.
200 ohms per centimeter of probe length or immersion depth can here be defined in a simple manner by correspondingly defining the amount of graphite particles. Another advantage of such a probe is the elasticity of the resistor body, whereby damage in case of undesired contact between ~-bottle 18 and resistor 22 can be prevented.

In probe 4g of FIGS. 11 and 12, the rod-shaped probe body 10 consists of a non-conductive plastic material. Two pads -27 of plastics are embedded with enclosed graphite particles at the lower, free measuring end of probe 4g on the circumference of probe body 10 at diametrically opposed points. Pads 27 have an elongated basic shape and extend at the same level in parallel with the probe axis. They are connected to the electronic evaluation means (not shown) ~ A~

2115~30 via lines 19 of steel wire that extend inside probe body 10. In the area of pads 27, probe body 10 is provided with a cylindrical lateral surface with which the contact surface of pads 27 is in alignment. Elongated milled portions are provided thereabove at both sides for reducing the probe cross-section while the upper connection portion of probe 4g is again substantially cylindrical.

As for probe 4g, one also obtains an ohmic resistance at both lines, the ohmic resistance being linearly dependent on the immersion depth in a conductive liquid. Therefore, the desired continuous and proportional measuring signal can easily be produced.

The filling unit 29 of FIG. 13 forms part of a rotary counterpressure filling machine (not shown in more detail) for filling bottles 18 with a C02 containing beverage. It has a housing 9 with a vertical hole 40 and a lateral liquid inlet 41 which communicates with an annular liquid vessel 42. An annular filling nozzle 14 is formed at the lower end of housing 9 and hole 40, respectively. The filling nozzle 14 is followed upwardly by a conical valve seat 16 which cooperates with a valve body 17 which is vertically movably supported in housing 9, and with the elastic sealing body 37 thereof. Beverage outflow via filling nozzle 14 into bottle 18 is controlled by the resultant liquid valve, i.e., with the aid of an actuating motor 43 acting on valve body 17 in a closing sense and of a spring 44 acting in an opening sense.

A substantially cylindrical gas pipe 28 of stainless steel is screwed into the lower end of a longitudinal hole 45 in valve body 17. The pipe communicates with an annular gas chamber 47 in housing 9 through the longitudinal hole 45 and a plurality of transverse holes 46 formed at ~he upper end thereof. Gas chamber 47 is connected to an annular pressurizing gas channel (not shown) via a plurality of 12 21~ 930 lines (not shown) and a controllable pressurizing gas valve 50.

Furthermore, there is provided a vertically movably supported centering bell 13 with a sealing ring lS for ensuring exact centering of the bottle opening during the lifting of a bottle 18 by a lifting means (not shown) and during the simultaneous introduction of gas pipe 28 into the interior of the bottle and also for ensuring a gas and liquid-tight seal between bottle 18, which is pressed against filling unit 29, and filling nozzle 14 during the filling operation.

A rod-shaped probe 4 with an elongated probe body 32 is concentrically seated within gas pipe 28 and the longitudinal hole 45 which is in aligment therewith. ~robe body 32 has a continuous round wire 34 of stainless steel with a diameter of about one millimeter. Wire 34 is fully surrounded in its central and upper portions by a substantially cylindrical insulating wrapper 35 of plastics. The insulating wrapper 35 has a plurality of integrally formed attachments 36 in the form of ribs or webs evenly distributed on the circumference thereof, which exactly center probe body 32 in the longitudinal hole 45 and in gas pipe 28, respectively, so that a continuous annular gas channel which is connected to gas chamber 47 is formed between the wrapper and the inner wall of the gas pipe 28 and the longitudinal bore 4S.

At the upper end, probe body 32 comprises a cylindrical thickened portion 51 which is attached in a gas-tight and replaceable manner by means of a screw sleeve 51 in a corresponding bore of valve body 17. The vertically movable valve body 17 is guided upwards out of housing 9 and is overtopped by a connection nipple 48 which is conductively connected to wire 34. A connector 49 is detachably mounted 13 211~930 thereon with an electric line 19 that leads to an electronic evaluation means (not shown).

The lower portion of wire 34 is entirely bare and forms an elongated measuring zone 30 of a length of about 50 mm.
Wire 34 terminates at a distance above the lower opening 33 of gas pipe 28, so that the measuring zone 30 lies fully within gas pipe 28 and is therefore well-protected against mechanical damage. Slightly above the upper end of measuring zone 30, gas pipe 28 comprises a plurality of additional lateral openings 31 which are still within bottle 18 pressed thereagainst and communicate with the interior thereof. Openings 31 are surrounded at a distance by a rotationally symmetrical protective cover 38 which is mounted on gas pipe 28 above openings 31 and opens downwards. Protective cover 38 prevents the inflow of beverage from the filling nozzle 14 through openings 31 into the interior of gas pipe 28. The filling level within gas pipe 28 thus corresponds exactly to the filling level within bottle 18 and increases smoothly and without any turbulences. This permits an especially accurate me~surement of the instantaneous filling level and the transformation thereof into a continuous measuring signal.

Protective cover 38 is provided at its lower end with a deflection cone 39 which deflects the inflowing beverage ~ -outwards to the inner wall of bottle 18. Protective cover 38 is followed upwardly by the sealing body 37 of the liquid valve which is provided with a cylindrical extension and may additionally be equipped with guide surfaces producing a twist in the inflowing beverage. Gas pipe 28 forms a structural unit with sealing body 37 and protective cover 38, with the unit being adapted to be unscrewed after removal of the filling nozzle 14 from valve body 17. Probe body 32 will then be freely accessible in the area of the elongated measuring zone 30. Probe body 32, in turn, can be removed upwards from valve body 17 and gas pipe 28 after f - ~
14 211~930 removal o~ the actuating motor 42, connector 49 and screw sleeve 52. Apart from gas pipe 28, valve body 17 consists of stainless steel and is grounded. Gas pipe 28 therefore serves as a ground electrode.

As soon as the level of the beverage flowing into bottle 18 has reached probe 4h during a filling operation, the actual values of the instantaneous filling level are continuously sensed by the probe and supplied to the electronic evaluation means. The values are, e.g., compared with set values and the sequence of the filling operation is controlled accordingly, e.g., by immediatley lowering valve body 17 by means of actuating motor 43 when the preselected filling level is reached. During the filling operation the gas which has been displaced from bottle 18 escapes first via the additional openings 31 and via the lower opening 33 and, as sQon as the latter has been closed by beverage, only via the additional openings 31. Gas chamber 47 is connected via a return gas valve 53 to an annular return gas channel (not shown).

As for probe 4i according to FIG. 14, the probe body 32 is identical with that according to FIG. 13. Gas pipe 54 which surrounds wire 34 via the insulation-free elongated measuring zone 30 and serves as a ground electrode is obliquely cut off at the lower end, so that its oblique opening is approximately at the level of the free end of wire 34. This facilitates threading of gas pipe 54 into the opening of a bottle 18 and prevents damage. Furthermore, the immersion of gas pipe 54 at one side into the rising liquid counteracts a delayed rise within gas pipe 54. Three small longitudinal slots 55 which are distributed over the circumference of gas pipe 54 and which substantially cover the measuring zone 30 and terminate at a sliqhtly higher level than said zone operate in the same sense. Hence, slots 55 serve to discharge the return gas, so that no additional openings 31 and no protective cover 38 are , ~
15 211~930 needed. The deflection cone 39 is directly formed on gas pipe 54.

As outlined in FIG. 14 in dash-dotted line, wire 34 may also slightly project beyond the lower opening of gas pipe 54. This further improves the immersion characteristics and also the rise characteristics of the liquid.

Claims

Method and Apparatus for Adjusting the Filling Level in Filling Machines for Vessels Patent Claims

1. Method for adjusting the filling level in filling machines for vessels, wherein the filling level is measured with the aid of a probe immersed into said vessel and is adjusted in response to a signal from said probe, characterized in that a continuous measuring signal which depends on the filling level is produced by means of said probe to obtain information about the instantaneous filling level at any time (t).

2. A method according to claim 1, characterized in that said measuring signal has a continuous and monotonous curve.

3. A method according to claim 1 or 2, characterized in that said measuring signal is substantially proportional to said filling level.

4. A method according to any one of claims 1 to 3, characterized in that a signal function S(t) which depends on time (t) is produced on the basis of said measuring signal, with the filling speed being derived from the gradient of said signal function.

5. A method according to any one of claims 1 to 4, characterized in that a voltage drop is sensed as a measuring signal.

6. A method according to any one of claims 1 to 4, characterized in that said filling level is measured capacitively.

7. A method according to any one of claims 4 to 6, characterized in that correction values are derived from the determined filling speed for influencing the actual and/or other filling operations.

8. A probe for adjusting the filling level in filling machines for vessels, comprising a probe body which is longitudinally immersed in the vessel to be filled and includes a plurality of measuring points for the filling level, characterized in that a plurality of measuring points (1a to 1n; 5, 6) are connected via at least one electronic component (2, 7, 11, 22, 26) to one another and/or to an electronic evaluation means.

9. A probe according to claim 8, characterized in that a plurality of measuring points (1a to 1n; 5, 6) are connected via at least one passive electronic component (2, 7, 11, 22, 26) to one another and/or to an electronic evaluation means.

10. A probe according to claim 9, characterized in that at least one of said passive electronic components is formed as an ohmic resistor (2).

11. A probe according to claim 9, characterized in that at least two electronic components are formed as anti-parallel connected diodes (7).

12. A probe according to claim 9, characterized in that at least one of said electronic components is formed as a capacitor (26).

13. A probe according to any one of claims 8 to 12, characterized in that said probe comprises a ground contact which is immersed into said vessel at least at such a low level as the lowest measuring point (1a;
5).

14. A probe according to claim 13, characterized in that said ground contact (3) is formed on said probe body (10).

15. A probe according to claim 13, characterized in that said ground contact is formed by a filling pipe or gas pipe (8) of a filling unit.

16. A probe according to any one of claims 8 to 15, characterized in that said measuring points (1a to 1n;
5, 6) are formed by contact zones of conductive material which are conductively connected to at least one electronic component (2, 7).

17. A probe according to claim 16, characterized in that, apart from said contact zones (1a to 1n; 5, 6), said components (2, 7) are also directly mounted in or on said probe body (10).

18. A probe according to any one of claims 8 to 15, characterized in that said measuring points (1a to 1n) are formed by the conductive surface of resistors (2, 11, 22).

19. A probe according to claim 18, characterized in that a plurality of measuring points (1a to 1n) are formed by a single elongated resistor (11, 22).

20. A probe according to claim 19, characterized in that said resistor (11) is provided between said contact zones (1a to 1n) with restricted portions that are filled with insulating material.

21. A probe according to any one of claims 8 to 19, characterized in that a plurality of measuring points (1a to 1n) are combined to form one single elongated measuring point.

22. A probe according to any one of claims 8 to 21, characterized in that it has a separate, preferably rod- or strip-shaped probe body (10).

23. A probe according to any one of claims 8 to 21, characterized in that said measuring points (1a to 1n) and possibly said ground contact are arranged on a filling pipe or gas pipe (8) of a filling unit.

24. A probe according to any one of claims 8 to 23, characterized in that said measuring points (1a to 1n;
5, 6) and said electronic components (2, 6, 11, 22) are connected through a single line (19) to said electronic evaluation means.

25. A probe according to any one of claims 19 to 24, characterized in that said resistor (22) consists of plastics including enclosed graphite particles.

26. A probe according to claim 25, characterized in that said resistor (22) is cylindrical and its outer surface serves as a contact surface.

27. A probe according to claim 25, characterized in that two elongated plastic pads (27) with enclosed graphite particles are embedded in a rod-shaped probe body (10) of insulating material at two diametrically opposed points.

28. A probe according to claim 27, characterized in that a line (19) which leads through said probe body (10) is connected to each of said plastic pads (27).

29. A probe according to any one of claims 8 to 28, characterized in that said measuring points or said elongated measuring point (30) are positioned inside a gas pipe (28) of a filling unit (29), said gas pipe (28) being immersed into said vessel to be filled and downwardly open.

30. A probe according to claim 29, characterized in that said elongated probe body (32) is concentrically arranged relative to the center axis of said gas pipe (28) to form an annular chamber.

31. A probe according to claim 29 or 30, characterized in that said probe body (32) terminates at a distance above the lower opening (33) of said gas pipe (28).

32. A probe according to any one of claims 29 to 31, characterized in that said probe body (32) includes a metal wire (24) which is exposed on all sides in an area forming said elongated measuring point (30) and is provided with an insulating wrapper (35) in the area positioned thereabove.

33. A probe according to claim 32, characterized in that said metal wire (34) consists of stainless steel and has a diameter of about 1 mm.

34. A probe according to any one of claims 29 to 33, characterized in that said probe body (32) is provided with a plurality of web-like attachments (36) which fix said body within said gas pipe (28).

35. A probe acccording to claim 34, characterized in that said attachments (36) which are distributed over the circumference of said probe body (32) are integrally formed with said insulating wrapper (35).

36. A probe according to any one of claims 29 to 35, characterized in that said probe body (32) is rigidly arranged within said gas pipe (28).

37. A probe according to any one of claims 29 to 36, characterized in that an additional opening (31) is shielded in said gas pipe (28) against penetrating liquid.

38. A probe according to claim 37, characterized in that said gas pipe (28) is surrounded at the level of said additional opening (31) at some distance by a protective cover (38) which is mounted at the upper end in liquid-tight fashion on said gas pipe (28) and is open at the lower end.

39. A probe according to claim 38, characterized in that said protective cover carries a deflection cone (39) for inflowing liquid preferably at the lower end.

40. A probe according to claim 38 or 39, characterized in that said protective cover (38) is upwardly followed by a sealing body (37) of a valve body (17), said sealing body (37) being mounted on said gas pipe (28).

41. A probe according to any one of claims 38 to 40, characterized in that said gas pipe (28) is detachably mounted within said valve body (17) of said liquid valve together with said protective cover (38) and, optionally, with said sealing body (37).

42. A probe according to any one of claims 29 to 41, characterized in that said gas pipe (28) is made of stainless steel and formed as a ground electrode.

43. A probe according to any one of claims 29 to 42, characterized in that said gas pipe (54) is beveled at its lower end in the area of its opening.

44. A probe according to any one of claims 29 to 43, characterized in that said gas pipe (54) is provided with at least one longitudinal slot (55) which substantially covers the elongated measuring point (30).

45. A probe according to any one of claims 29 to 44, characterized in that said probe body (32) slightly projects from the lower opening of said gas pipe (54).

46. A probe according to at least one of claims 29 to 45, characterized in that said measuring points or said elongated measuring point (30) are fully positioned within said gas pipe (28, 54).

47. A probe according to any one of claims 29 to 46, characterized in that said gas pipe (28) is provided above the highest measuring point or the upper end of said elongated measuring point (30) with at least one additional opening (31) that communicates with the interior of a vessel.