DEVICE AND METHOD FOR PROVIDING A CLEANING FLUID

Abstract

A device for providing at least one cleaning fluid, having a collecting container which by means of a pump and a fluid line is connected to a first cleaning container within which there is received a first cleaning component, further comprising a sensor unit and a control unit for controlling the pump and for interrupting a fluid loop depending on a concentration measured by the sensor unit in a contactless way.

Claims

1. A device for providing a cleaning fluid, comprising: a collecting container for collecting cleaning fluid; a first cleaning container arranged above said collecting container and holding a first cleaning component being in fluid connection to said collecting container; a pump; a fluid line being connected via said pump to said collecting container within a loop; a sensor unit being configured for contactless concentration measurement by measuring hydrostatic pressure of said cleaning fluid; a control unit for controlling at least a feeding of cleaning component from said first cleaning container into said collecting container depending on a concentration of said cleaning fluid measured by means of said sensor unit.

2. A device for providing a cleaning fluid, comprising: a collecting container for collecting cleaning fluid; a first cleaning container holding a first cleaning component and being in fluid connection to said collecting container; a pump; a fluid line being connected via said pump to said collecting container within a loop; a sensor unit being configured for contactless concentration measurement of said cleaning fluid; a control unit for controlling at least a feeding of cleaning component from said first cleaning container into said collecting container depending on a concentration of said cleaning fluid measured by means of said sensor unit.

3. The device of claim 2, wherein said cleaning container is arranged above said collecting container.

4. The device of claim 2, wherein said sensor unit is configured for measuring a weight of said collecting container.

5. The device of claim 2, wherein said sensor unit is configured for measuring a hydrostatic pressure of said cleaning fluid.

6. The device according to claim 2, wherein said sensor unit is configured for measuring an electric capacity within said cleaning fluid.

7. The device of claim 2, wherein said sensor unit is configured for measuring a refractive index of said cleaning fluid.

8. The device of claim 2, wherein said sensor unit is configured for measuring a speed of sound within said cleaning fluid.

9. The device of claim 2, characterized by a second cleaning container holding a second cleaning component.

10. The device of claim 2, wherein said collecting container and the cleaning container are separated from each other by a separator having solid retarding characteristics.

11. The device of claim 10, wherein said separator is selected from the group consisting of a membrane, a sieve, and a fabric.

12. The device of claim 2, further comprising a stirring device for stirring said cleaning fluid within said collecting container.

13. The device of claim 2, further comprising at least one nozzle fed with cleaning fluid from said pump through said fluid line for spraying cleaning fluid against a cleaning component within the cleaning container.

14. The device of claim 13, wherein said nozzle is arranged below a bottom side of said cleaning component within said cleaning container.

15. The device of claim 2, further comprising a separating wall arranged within said collecting container or said fluid line cooperating with said sensor unit for allowing said contactless concentration measurement of said cleaning fluid through said separating wall.

16. The device of claim 15, wherein said separating wall is configured as a flexible membrane.

17. The device of claim 2, wherein said control unit is configured for interrupting said feeding of cleaning component from said first cleaning container into said collecting container and for stopping said pump upon detecting a preset concentration of cleaning fluid within said collecting container.

18. A method for providing a cleaning fluid with a particular concentration, comprising the following steps: (a) providing a fluid within a collecting container; (b) circulating the fluid within a loop through said collecting container and a cleaning container; (c) dissolving at least one cleaning component by means of said fluid, whereby said fluid is enriched with dissolved cleaning component and said cleaning fluid is obtained; (d) detecting a concentration of said cleaning fluid in a contactless way; and (e) interrupting said dissolving within step (c) as soon as a predefined concentration of dissolved cleaning component within said cleaning fluid is detected.

19. The method of claim 18, wherein a measurement is performed by measuring at least one selected from the group consisting of a weight of said collecting container, a hydrostatic pressure of said cleaning fluid within said collecting container, an electric capacity of said cleaning fluid within said collecting container, speed of sound of said cleaning fluid within said collecting container, and a refractive index of said cleaning fluid within said collecting container.

20. The method of claim 18, wherein a dissolving of at least one cleaning component is performed by spraying fluid from below onto a surface of said cleaning component being located within said cleaning container.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0091] Further features and advantages of the invention can be taken from the subsequent description of preferred embodiment with reference to the drawings. In the drawings show:

[0092] FIG. 1 a first schematic representation of the device according to the invention;

[0093] FIG. 2A a schematic representation of a capacitive sensor unit;

[0094] FIG. 2B a schematic representation of a sensor unit for measuring the speed of sound;

[0095] FIG. 2C a schematic representation of a refractive sensor unit;

[0096] FIG. 2D a schematic representation of a sensor unit for measuring the hydrostatic pressure within the collecting container; and

[0097] FIG. 3 a schematic representation of the device according to the invention, comprising a second cleaning component.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0098] FIG. 1 shows a first device 100 according to the invention for providing at least one cleaning fluid 10.

[0099] The device 100 according to FIG. 1 comprises a cleaning component 12, which is received within a first cleaning container 14. The first cleaning container 14 with the cleaning component 12 received therein is held above the collecting container 16 within a receptacle 18. The receptacle 18 may for example be configured with inner threads and may be located at the top side of the collecting container 16. The cleaning container 14 may then be screwed with assigned outer threads into the inner threads. Of course there is also the possibility to design this connection in a different way, such as a click connection with locking means or with a positive connection.

[0100] The cleaning container 14 that is screwed into the collecting container 16 at its bottom side comprises an orifice through which a nozzle 20 pointing upwardly protrudes into the cavity below the cleaning component 12. The nozzle 20 herein is arranged at the collecting container 16. The nozzle 20 preferably is a spray nozzle. The nozzle 20 sprays cleaning fluid 10 being provided within the collecting container 16 into the cleaning container 14 onto the bottom side 28 of the cleaning component 12 which is dissolved thereby. According to the invention the fluid is an aqueous solution which initially does not contain any dissolved cleaning component 12. Preferably the fluid is configured as water. By enriching dissolved cleaning component 12 within the fluid, the fluid becomes the cleaning fluid 10.

[0101] During running of pump 24 by means of the nozzle 20 continuously a spray jet 26 is directed onto the bottom side 28 of the cleaning component 12. The fluid, or the cleaning fluid 10, respectively, sprayed onto the bottom side 28 of the cleaning component 12 herein partially dissolves the cleaning component 12 and flows back into the collecting container 16. Thereby the concentration of dissolved cleaning component 12 changes within the cleaning fluid 10 within the collecting container 16. The cleaning fluid 10 is pumped within a fluid loop via a fluid line 22, the nozzle 20, the cleaning container 14 and the collecting container 16, until there appears a defined set concentration within the cleaning fluid 10.

[0102] The solution of the cleaning component 12 and the fluid circulation connected therewith is interrupted as soon as an assigned sensor unit 32 configured as a pressure sensor registers the reaching of a predefined set concentration. The interruption of the fluid circulation or of the feeding of new cleaning component 12, respectively, is controlled by the control unit 42. The latter controls the pump 24. Since the nozzle 20 in the given design is activated only when the pump 24 is active, upon switching off the pump 24 also the feeding of cleaning component 12 is interrupted.

[0103] Optionally the collecting container 16 in addition comprises a mixing device 44. This mixing device 44 may be configured as a propeller, as a tube wing, as a blade wing, as a mixing tube, as a stirring rod or similar. The mixing device 44 mixes the cleaning fluid 10 within the collecting container 16. By this design a deposition of cleaning component 12 or a precipitation of cleaning component 12, respectively, is impeded. Thus, it is also avoided that the concentration within the cleaning fluid 10 changes during longer storage. Thus always a homogeneous cleaning fluid 10 can be provided having a defined set concentration.

[0104] FIG. 1 shows that the pump 24 is arranged within the fluid line 22 which starts at an outlet 30 at the bottom end of the collecting container 16 and ends with an orifice configured as a nozzle 20. By means of the pump 24 the cleaning fluid 10 being provided within the collecting container 16 is fed to the nozzle 20 which sprays against the bottom side of the cleaning component 28 and which may be configured as a fan-shape, a cone-shape or as a point-by-point spraying jet 26, so that cleaning component 12 dissolves within the cleaning fluid 10.

[0105] The device 100 according to FIG. 1 comprises a sensor unit 32 being configured as a pressure sensor, e.g. in the form of a piezo sensor, upon which the collecting container 16 rests. The sensor unit 32 is configured so that it can detect the weight of the collecting container 16 which is influenced by the hydrostatic pressure within the collecting container 16. The hydrostatic pressure changes by means of the solution of cleaning component 12 so that by means of the measured pressure change the concentration of the cleaning fluid may be derived. The volume during the solution process remains almost equal, so that by the variation of the hydrostatic pressure the density and thereby the concentration of the cleaning fluid 10 can be derived.

[0106] The collecting container 16 is arranged vertically movably so that a weight change of the collecting container 16 can be registered by the sensor unit 32.

[0107] The sensor unit 32 is connected with a control unit 42 which controls the pump 24. As soon as the sensor unit 32 registers a certain set pressure, the sensor unit 42 switches off the pump. In this way the feeding of fluid to the nozzle 20 ends so that no further cleaning component 12 is dissolved.

[0108] Alternative sensor units are shown exemplarily in FIG. 1 as a sensor unit 34 being configured as a capacitive sensor located at the wall of the collecting container 16 for filling level measurement, as well as a refractive sensor unit 40 at the fluid line 22, both shown in dashed lines.

[0109] The measurement principle of the contactless capacitive measurement relies on the variation of the capacity depending on the variation of the concentration of dissolved cleaning component 12 within the cleaning fluid 10. Herein in particular the different permittivities of the cleaning fluid 10 to be measured, are exploited.

[0110] The capacitive sensor unit 34 preferably is located at the wall of the collecting container 16 or at the two walls of the fluid line 22 facing each other. For this configuration the wall of the collecting container 16 or of the fluid line 22 is preferably electrically non-conductive, since otherwise measurement inaccuracies may occur. In a preferred design the wall may also comprise a window defining a region within which the wall is configured non-conductive. In addition the sensor unit 34 is not in direct contact with the cleaning fluid 10.

[0111] The capacitive sensor unit 34 comprises at least two electrodes between which the measurement field is provided which is influenced by the concentration of the cleaning fluid 10 provided therein. The two electrodes form the plates of a capacitor. Due to different permittivities and the different capacities caused thereby, the concentration can be determined.

[0112] Preferably for the capacitive sensor unit 34 an oscillation circuit including an oscillator is utilized, the frequency of which is influenced by the cleaning fluid, as subsequently described with reference to FIG. 2A.

[0113] When the sensor unit 34 is located at the upper third of the collecting container 16, in this way the filling height of the fluid within the collecting container 16 can be detected directly. The sensor unit 34 reacts very sensitive to the variation of the filling height, due to the different permittivities of air and of the fluid, or the cleaning fluid 10, respectively.

[0114] FIG. 2A shows the schematic representation of a section of the sensor unit 34. This sensor unit 34 comprises a sensor electrode 50 which is mounted at the wall of the collecting container 16. To this end the wall is configured so that it does not disturb the capacitive measurement. This sensor electrode 50 generates an electrical field 52, the so-called active zone. The electric field 52 preferably is generated by means of an oscillation circuit 54. The capacity between the active electrode 50 and the cleaning fluid 10 within the measuring cell 56 to be measured can be registered by means of the sensor electrode 50 and can be evaluated. By the change of concentration in the direct environment of the electric field 52 of the sensor 50 the capacity changes and thus influences the oscillation frequency of the oscillator. This is detected by means of a measuring unit 56 or directly by means of the controller 42 which preferably comprises a micro processor.

[0115] If the capacitive sensor unit 34 is attached to the fluid line 22, then the two electrodes are located at the two opposite walls. Thereby a variation in the capacity by the variation of the concentration of the circulating cleaning fluid 10 has a direct impact on the oscillating circuit closed via the measuring cell and thus changes the frequency thereof.

[0116] A further possible configuration of the sensor unit according to the invention is the concentration measurement by means of the speed of sound, as depicted in FIG. 2B by the sensor unit 35. Herein a transmitter 36 transmits a sound wave pulse through the collecting container 16 being measured by the receiver 38. By means of the measurement the running time of the sound pulse between the transmitter 36 and the receiver 38, or by measuring the phase difference between the transmitter signal and the receiver signal, respectively, the speed of sound can be computed. From this again the concentration of the cleaning fluid can be derived.

[0117] By means of calibrating solutions a calibrating speed of sound can be determined. As soon as this calibrating speed of sound is registered within the measuring cell 62, the control unit 42 can switch off the pump 24, or can interrupt the feeding of cleaning component 12 into the collecting container 16, respectively.

[0118] The sound waves 58 can be generated by means of an oscillating circuit 54. In a preferred configuration the transmitter 36 may be configured as a speaker, for example as piezo-electric quartz oscillator or ceramic oscillator. This may be fed with an alternating voltage with the self-resonance frequency or with a harmonic thereof.

[0119] The transmitter 36 as well as the receiver 38 are not in direct contact with the cleaning fluid 10, but are separated from cleaning fluid 10 for example by means of a membrane 60. This membrane 60 is configured so that the sound waves 58 can be transmitted and received. The membrane 60 preferably consists of a chemically inert material, such as PTFE, so that it cannot be attacked by the aggressive cleaning fluid 10.

[0120] The sent sound waves 58 may for instance be ultrasound waves which are transmitted by means of piezo sensors. With such a measurement method the concentration of the cleaning fluid 10 can be determined very precisely, since the speed of sound within a fluid depends on the concentration of the individual components.

[0121] Preferably, the transmitter 36 and the receiver 38 are located at the outer wall of the collecting container 16 on respectively opposite sides to each other, at the same height, so that in this way a long measuring distance is provided.

[0122] A further possible design of the sensor unit according to the invention is a refractive sensor unit 40 according to FIGS. 1 and 2C, respectively. Herein the concentration of dissolved cleaning component 12 within the fluid can be determined by means of measuring the refractive index within the cleaning fluid 10. The refractive index varies depending on the concentration. To this end a light source 66 transmits a light pulse which is totally reflected at the transparent wall of the fluid line 22. The reflected light ray is detected by means of the receiver 68.

[0123] Since the angle of total reflection depends on the refractive index of the cleaning fluid, therefrom the concentration of the cleaning fluid can be derived.

[0124] FIG. 2C shows a schematic representation of a section of the sensor unit 40 being configured as a refractometer.

[0125] The receiver 68 preferably is configured as an optical sensor. The transmitter 66 as well as the receiver 68 are located outside of the wall. The wall preferably is configured as the wall of the fluid line 22. The wall is configured so that it does not interrupt the light ray 70 undesirably or absorb the light rays 70. Preferably the wall at this region of the transmitter 66 and the receiver 68 comprises a transparent window.

[0126] By means of calibrating solutions the refractometer can be calibrated to a desired set concentration.

[0127] A further configuration of the sensor unit is shown in FIG. 2D and depicted in total with 41. This is a particularly simple and reliable measuring method by means of measuring the hydrostatic pressure at the bottom of the collecting container 16.

[0128] To this end at the bottom of the collecting container 16 there is arranged a measuring line 46 that is filled with air and that is guided upwardly beyond the maximum possible level of the liquid level within the collecting container 16. At the end of the measurement line 46 there is provided a pressure sensor 48. If the pressure sensor 48 detects the reaching of a particular threshold value, then the concentration of the cleaning fluid 10 has reached the given set concentration.

[0129] FIG. 3 shows a third device 300 according to the invention for providing at least one cleaning fluid 10.

[0130] The device 300 according to the representation in FIG. 3 comprises a first cleaning container 82 and a second cleaning container 84. These are mounted facing with their open side downwardly within the top of the collecting container 16. The first and second cleaning containers 82 and 84 comprise a first and a second cleaning component 86 and 88, for instance in block form. The respective bottom sides of the first and second cleaning components 86 and 88 are wetted by means of spraying jets emerging from a first nozzle 90 and a second nozzle 92, so that the cleaning components 86 and 88 are partially dissolved and can be dissolved within the cleaning fluid 10. The fluid from a first feed passes over to the first and second pump 24. The pumps 24 of the first nozzle 90 and of the second nozzle 92, respectively each pump cleaning fluid 10 by means of an assigned fluid line 22 into the assigned nozzles 90, 92, so that the bottom sides of the first and second cleaning components 86 and 88 are wetted. Herein the fluid line 22 may comprise interposed valves 94, preferably magnetic valves. The filling volume of the cleaning fluid 10 being located within the collecting container 16 can be controlled by means of a volume control 96.

[0131] Within the two cleaning containers 82 and 84 according to the representation in FIG. 3 two cleaning components 86 and 88 of equal composition may be located. Herein the second cleaning component 88 may serve as a reserve, so that always it can be ensured that enough cleaning fluid 10 can be made. In this configuration the device 300 is preferably configured so that the fluid loop initially passes through the first cleaning container 82 as long as the sensor unit 32 does not detect any change in concentration anymore. As soon as the first cleaning container 82 does not have any more cleaning component 86, since the latter has been fully dissolved by the cleaning fluid 10, then the control unit can switch over the fluid loop so that the second cleaning component 88 is dissolved from the second cleaning container 84. In this way it can be ensured that always within the collecting container 16 there is a cleaning fluid 10 with a defined concentration. The selection of the two nozzles 90 and 92 can be controlled by means of valves 94. The valves 94 preferably are configured as magnetic valves.

[0132] FIG. 3 further shows a retention device 98 which divides the cleaning components 86 and 88 from the collecting container 16 and the cleaning fluid 10 provided therein. Such a retention device 98 preferably has solid retarding characteristics. Such a retention device 98 may e.g. be configured as a membrane, as a sieve, or as a fabric.

[0133] When dissolving the cleaning component 86 and 88 there may occur a detachment of larger fractions of cleaning components 86 and 88. To avoid that larger amounts of cleaning components 86 and 88 get into the cleaning fluid 10, the retention device 98 retards these larger amounts of cleaning components 86 and 88. In this way it can be ensured that the concentration cannot change in an undesired way.

[0134] As soon as the cleaning fluid 10 reaches the defined set concentration, the pump 24 is stopped and the feeding of cleaning component 86 and 88, respectively, is interrupted.

[0135] The circulation of the cleaning fluids 10, in particular the dissolving of cleaning components 86 and 88, respectively, is controlled by means of the control unit 42 (not shown in FIG. 3) according to the information of the sensor unit 32. If the sensor unit 32 detects that within the collecting container 16 there is the set concentration, it forwards this information to the control unit 42 so that the control unit stops the circulation of the cleaning fluid 10. If the defined concentration has not been reached yet, the circulation of the cleaning fluid 10 continues.

[0136] According to FIG. 3 the hydrostatic pressure is measured by means of a measuring line 46 and a pressure sensor 48, as previously explained with reference to FIG. 2D.