DEVICE AND METHOD FOR MEASURING AT LEAST ONE PARAMETER OF A TREATMENT FLUID IN A SURFACE TREATMENT SYSTEM

Abstract

A device for measuring at least one parameter of a treatment fluid in a surface treatment system, having an acoustic surface wave measurement device, which has a measurement chamber, which delimits a measurement volume for the treatment fluid, and converters for acoustic surface waves, which are arranged on the measurement chamber, and is designed to provide at least one measurement output signal, which is dependent on the current state of the treatment fluid in the measurement volume, using the converters. The device has an evaluation unit having a time progression recording device which is designed to record the temporal progression of the at least one measurement output signal of the acoustic surface wave measurement device, and a parameter determination device, which is designed to determine the value of the at least one parameter to be measured from the recorded temporal progression of the measurement output signal of the acoustic surface wave measurement device.

Claims

1. A device for measuring at least one parameter of a treatment fluid in a surface treatment system, comprising: a) an acoustic sound wave measurement device which has a measurement chamber which delimits a measurement volume for a treatment fluid, and has converters for acoustic sound waves, which are arranged on the measurement chamber, and is designed, using the converters, to provide at least one measurement output signal, which is dependent on the current state of the treatment fluid in the measurement volume, and b) an evaluation unit comprising a time progression recording device which is designed to record temporal progression of the at least one measurement output signal of the acoustic sound wave measurement device, and a parameter determination device, which is designed to determine a value of at least one parameter measured from the recorded temporal progression of the measurement output signal of the acoustic sound wave measurement device.

2. The device as claimed in claim 1, wherein the acoustic sound wave measurement device is an acoustic surface wave measurement device, and the converters for acoustic sound waves are converters for acoustic surface waves.

3. The device as claimed in claim 1, wherein the parameter determination device (76) comprises a comparison device which is designed to compare the recorded temporal progression (100) of the at least one measurement output signal (MS) with reference progressions (102) that are stored in a database.

4. The device as claimed in claim 1, wherein the parameter determination device (76) comprises an expert system.

5. The device as claimed in claim 1, wherein means (34, 36, 38) for introducing, holding and removing the treatment fluid (16) are provided in the measurement chamber (32).

6. The device as claimed in claim 5, wherein a controller (48) is provided which is designed to actuate the means (34, 36, 38) for introducing, holding and removing the treatment fluid (16) into and from the measurement chamber (32) in such a way that the treatment fluid (16) remains in the measurement volume for a predetermined period of time.

7. The device as claimed in claim 6, wherein the predetermined period of time is at least long enough that a measurable change results in the temporal progression of the at least one measurement output signal (MS) as a result of the separation in the treatment fluid (16).

8. The device as claimed in claim 1, wherein claims, characterized in that the means (34, 36, 38) for introducing, holding and removing are arranged in such a way that the treatment fluid (16) is introduced into the measurement chamber (32) from below.

9. The device as claimed in claim 1, wherein the measurement chamber (32) has larger dimensions in the vertical direction than in the horizontal direction.

10. The device as claimed in claim 1, wherein the time progression recording device (74) is designed to record a plurality of different measurement output signals (MS) of the acoustic sound wave measuring device (68).

11. The device as claimed in claim 1, wherein the parameter determination device (76) is designed to compare the temporal progressions (100) of a plurality of different measurement output signals (MS) with respective reference progressions (102).

12. The device as claimed in claim 1, wherein the parameter determination device (76) is designed to determine the composition of the treatment fluid (16) in terms of at least three components (A, B, C) as the parameter to be measured.

13. An immersion treatment system (10) for the treatment of objects in a treatment fluid comprising the device for the measurement of at least one parameter of treatment fluid as claimed in claim 1.

14. A method for measuring at least one parameter of a treatment fluid of a surface treatment system, the method comprising the following steps: a) introducing a treatment fluid into a measurement chamber of an acoustic sound wave measurement device, wherein the treatment fluid is initially in a homogeneous, mixed condition; b) recording a temporal progression of a measurement output signal of the acoustic sound wave measurement device while the treatment fluid is held in the measurement chamber and the components contained therein continue to separate; c) determining a parameter to be measured from the temporal progression of the measurement output signal.

15. The method for treating objects of claim 14, wherein at least one parameter of the treatment fluid is monitored by measurement while objects are being treated.

Description

SHORT DESCRIPTION OF THE DRAWINGS

[0037] Exemplary embodiments of the invention are explained in more detail below with reference to the drawings. Here:

[0038] FIG. 1 shows a schematic illustration of an immersion treatment system with an acoustic surface wave measurement device for the determination of the properties of a treatment fluid;

[0039] FIG. 2 shows a schematic illustration of the acoustic surface wave measurement device, including the wave signals that occur in that connection;

[0040] FIG. 3a shows a schematic illustration of the treatment fluid in the acoustic surface wave measurement device at the start of the measurement according to the invention;

[0041] FIG. 3b shows a schematic illustration of the treatment fluid in the acoustic surface wave measurement device during the measurement according to the invention;

[0042] FIG. 3c shows a schematic illustration of the treatment fluid in the acoustic surface wave measurement device at the end of the measurement according to the invention;

[0043] FIG. 4 shows a diagram of a recorded temporal progression of a measurement output signal of the acoustic surface wave measurement device;

[0044] FIG. 5 shows diagrams of reference progressions and recorded progressions for the purposes of explaining the parameter determination through comparison.

DESCRIPTION OF PREFERRED EXEMPLARY EMBODIMENTS

[0045] FIG. 1 shows an immersion treatment system, identified as a whole with 10, for objects to be treated such as vehicle bodywork or parts thereof. The immersion treatment system 10 comprises an immersion bath 12 with an overflow bath 14 in which an immersion treatment fluid 16, which is typically composed of a large number of components, is held.

[0046] In order to control various physical and/or chemical parameters of the immersion treatment fluid 16, in particular its composition in terms of pH value, paint proportion, binding agent proportion, temperature etc. during the immersion treatment process, the immersion bath 12 is integrated by way of the overflow bath 14 into a conditioning circuit 18 known as such from, for example, DE 10 2014 006 795 A1 and not to be described in more detail for the immersion treatment fluid 16. Substances can be added to and/or removed from the immersion treatment fluid 16 at an inlet 19 with the aid of the conditioning circuit 18. Substances can be added or removed here manually by the operator, or this may also be done partially and/or fully automatically.

[0047] As can furthermore be seen in the right-hand part of FIG. 1, a flushing bath 22 is shown schematically, in which flushing fluid 24 is located which can be used in a rear section of the immersion treatment system 10, for example for flushing objects that have already been treated.

[0048] A measurement device 30 for the measurement of various physical and/or chemical parameters of the immersion treatment fluid 16 is arranged schematically on the left in FIG. 1 positioned next to the immersion bath 12.

[0049] For this purpose, the measurement device 30 comprises a vertical pipe segment 32 as a measurement chamber, at the inlet of which a valve 34 and at the outlet of which a valve 36 are located. A pump 38 precedes the inlet-side valve 34, and is in turn connected to the immersion bath 12. The pipe segment 32 of the measurement device 30 can in this way be filled with immersion treatment fluid 16 from the immersion bath 12 when the valve 34 is open and the pump 38 is actuated. Since the inlet to the pipe segment 32 is arranged at the bottom end in the vertical sense, filling takes place from below.

[0050] At the output end the pipe segment 32 is connected through the valve 36 and the return line 40 to the overflow bath 14, so that the immersion treatment fluid 16 can be returned to it after the measurement.

[0051] The pipe segment 32 is connected at the inlet end via a flushing line 42 and a valve 44 to a pressure inlet 46 to the flushing bath 22 for this purpose. With the aid of this flushing line 42 the pipe segment 32 can, when needed, be flushed with the aid of the flushing fluid 24, whereby the immersion treatment fluid 16 that has already been measured is removed from the pipe segment 32.

[0052] For actuation of these processes, the measurement device 30 has a controller 48, which here is realized, together with an evaluation unit 50, in a conventional PC 52, and connected to the valves 34, 36, 44 and to the pump 38.

[0053] As can be seen from FIG. 2, at the pipe segment 32 the measurement device 30 here comprises by way of example four converters for acoustic surface waves, which are identified at the input end with reference signs 60 and 62 and at the output end with reference signs 64 and 66. The converters 60, 62, 64 and 66 are connected to an SAW evaluation system 68 which performs both the actuation and the evaluation of the converter signals, and which provides various measurement output signals which depend on the condition of the immersion treatment fluid in the pipe segment 32 at its digital output 70.

[0054] The SAW evaluation system 68 can, for example, couple an excitation signal 72 in at the converter 60. This travels in part along the pipe segment 32 itself, and is received by the converter 64 as the first wave group signal 1WG. Another part of the excitation signal 72 couples into the immersion treatment fluid 16 in the measurement volume, and crosses this in the direction of converter 66. It is then received there as the second wave group signal 2WG. One evaluation option of the SAW evaluation system 68 can now for example consist in determining the time delay between the wave group signal 1WG and the wave group signal 2WG, in order to deduce from this the speed of sound in the immersion treatment fluid 16. The value of the speed of sound can then be output at the digital output 70.

[0055] Reference is made to the already cited document WO 2010/136350 A1 for possible SAW evaluation methods, since the details of the SAW evaluation are not relevant for the present invention. This is because the pipe segment 32, the converters 60, 62, 64 and 66 and the SAW evaluation system 68 here represent an acoustic surface wave measurement device which can be integrated into the measurement arrangement 30 as a black box component. The SAW evaluation system 68 can, however, also of course be realized together with the controller 48 and the evaluation unit 50 in the PC 52, and optimized for the measurement purposes that are present.

[0056] Exemplary measurement output signals MS that are output at the acoustic surface wave measurement device can be: the amplitude of the surface wave 0WG from converter 60 to converter 64, which corresponds to a pure propagation along the pipe segment 32; the amplitude of the surface wave from converter 64 to converter 60, which corresponds to a pure propagation along the pipe segment 32; the amplitude of the first wave group 1WG from converter 60 to converter 66, which corresponds to a single crossing of the fluid 16; the amplitude of the first wave group from converter 66 to converter 60, which corresponds to a single crossing of the fluid; the amplitude of the second wave group 2WG from converter 60 to converter 64, which corresponds to crossing the fluid 16 twice; the amplitude of the second wave group 2WG from converter 64 to converter 60, which corresponds to crossing the fluid 16 twice; the group velocity of the surface wave in the pipe segment 32; the speed of sound of the fluid 16; the amplitude of the nth wave group, which corresponds to crossing the fluid 16 n times.

[0057] As can furthermore be seen from FIG. 2, the SAW evaluation system 68 is connected to a time progression recording device 74 of the evaluation unit 50, which records the values of the measurement output signals MS provided at the digital output 70, and stores them in a memory.

[0058] The evaluation unit 50 furthermore comprises a parameter determination device 76 which accesses the memory of the time progression recording device 74 and its own database in order to compare the measured temporal progression 100 of a measurement output signal with reference progressions 102 (see FIGS. 4 and 5). The evaluation unit in this way determines a predetermined parameter as a result of the measurement of the measurement arrangement 30.

[0059] The measurement apparatus 30 works as follows:

[0060] If, for example, a measurement of the composition of the immersion treatment fluid 16 is to take place, the controller 48 thus opens the inlet valve 34 and, with the aid of the pump 38, conveys immersion treatment fluid 16 into the pipe segment 32.

[0061] The situation in the pipe segment 32 immediately after the inlet valve 34 has been closed is as shown in FIG. 3a. The here exemplary components A (circle), B (pentagon), C (triangle) are distributed in a homogeneous mixture in the pipe segment 32.

[0062] With the aid of the converters 60, 62, 64 and 66, the SAW evaluation system 68 couples acoustic surface waves into the measurement volume, where they are influenced by the non-homogeneously mixed immersion treatment fluid 16. The result of the SAW evaluation is then supplied as a first value 90 of the measurement output signal to the time progression recording device (cf. FIG. 4).

[0063] Since the inlet valve 34 still remains closed, the immersion treatment fluid 16 settles in the pipe segment 32, and a sedimentation effect occurs as a result of gravitational force, so that the components A, B, C partially separate. This is suggested in FIG. 3b by the collection of the denser component A in the lower region of the pipe segment 32. A new SAW measurement with the aid of the acoustic surface wave measurement device supplies a second value 92 for the recorded progression (cf. FIG. 4) which differs from the first value 90 as a result of the partial separation.

[0064] After a further period of time, the immersion treatment fluid 16 has separated further. A further SAW measurement supplies a third value 94.

[0065] During the period in which the immersion treatment fluid 16 remains in the pipe segment 32, a real measurement device 30 will perform a large number of SAW measurements, since the SAW measurements take place quickly in comparison with the sedimentation.

[0066] As is suggested in FIG. 5, the progression 100 recorded in this way is then compared with previously recorded reference progressions 102 which have been recorded for defined compositions of the immersion treatment fluid 16. The measured composition then corresponds to the composition whose reference progression 102 has the greatest similarity to the recorded progression 100.

[0067] In detail, the comparison can take place by means of an expert system which is based on known classification algorithms. In particular, a plurality of recorded progressions of different measurement output signals MS of the acoustic surface wave measurement device 68 can be compared with associated reference progressions, wherein existing correlations that permit a comprehensive evaluation can be taken into account. This is suggested by the two lower diagrams in FIG. 5, which show the progression 100 for other measurement output signals MS and the associated reference progressions 102.

[0068] The evaluation unit 50 can in this way determine a large number of different parameters of the immersion treatment fluid 16.