TREATMENT UNIT COMPRISING A SENSING UNIT FOR THE MEASUREMENT OF ANTIMICROBIAL ACTIVES

Abstract

The invention relates to a medical treatment unit, in particular a dental treatment unit, comprising a water leading system and a measurement unit for the quantitative measurement of an antimicrobial agent content in water contained in the water leading system.

Claims

1. A medical treatment unit, comprising: a water leading system; a control unit; and a water treatment unit for the addition of an antimicrobial agent to treatment water contained in the water leading system; wherein the medical treatment unit further comprises a sensing unit for the quantitative measurement of a content of antimicrobial agents in the treatment water contained in the water leading system, the sensing unit being arranged downstream the water treatment unit in the water leading system.

2. The treatment unit according to claim 1, wherein the antimicrobial agent is ozone or an aqueous solution of hydrogen peroxide, a silver salt like silver nitrate, 2-phenoxyethanol, chlorine, hypochloric acid, a hypochlorite, an amine, a quaternary ammonium compound, iodine, or a combination thereof.

3. The treatment unit according to claim 2, wherein the antimicrobial agent is hydrogen peroxide, a silver salt, 2-phenoxyethanol, or a combination thereof.

4. The treatment unit according to claim 1, wherein a marker substance is added to the treatment water in the water treatment unit, wherein the marker substance, which does not have antimicrobial activity itself, is added to the treatment water in an amount proportional to the addition amount of the antimicrobial agent, wherein the measurement unit is configured to measure the amount of the marker substance, and wherein the control unit is configured to determine the content of the antimicrobial agent in the treatment water by proportionality calculations.

5. The treatment unit according to claim 1, wherein measurement unit comprises an UV-vis spectrometer configured for transmission or extinction measurement; or a NIR spectrometer.

6. The treatment unit according to claim 5, wherein the measurement path is 0.5 mm to 20 mm.

7. The treatment unit according to claim 6, wherein the measurement path is 2 mm to 10 mm.

8. The treatment unit according to claim 1, wherein the measurement unit comprises one or more of a temperature sensor for sensing the water temperature, a heating or cooling unit for influencing the water temperature, a pH sensor, or an electrochemical sensor.

9. The treatment unit according to claim 1, wherein control unit is configured for automatic identification and quantification of antimicrobial agents in the treatment water on the basis of data received from the detecting unit.

10. The treatment unit according to claim 1, wherein the treatment unit comprises two serially arranged measurement units to detect a possible decrease of antimicrobial agent concentration in a section of the water leading system.

11. The treatment unit according to claim 1, wherein the treatment unit comprises a detecting unit which is signal connected to the control unit, wherein the detecting unit is configured to read in codes, which are optionally included on antimicrobial agent or marker substance containers, and wherein the control unit is configured to identify antimicrobial agents or marker substances and concentrations on the basis of a read in code and initiate an automatic calibration of sensors or an automatic evaluation of measurement signals based thereon.

12. The treatment unit according to claim 1, wherein the treatment unit is a dental treatment unit.

13. A method of measuring a content of an antimicrobial agent in treatment water of a medical treatment unit, wherein the treatment unit comprises a water leading system and a water treatment unit for adding the antimicrobial agent to the treatment water, which is contained in the water leading system, and wherein the content of the antimicrobial agent is measured in a measurement unit arranged downstream the water treatment unit.

14. The method according to claim 13, wherein the water treatment unit comprises: a water leading system; a control unit; and a water treatment unit for the addition of an antimicrobial agent to the treatment water contained in the water leading system; wherein the medical treatment unit further comprises a sensing unit for the quantitative measurement of a content of antimicrobial agents in the treatment water contained in the water leading system, the sensing unit being arranged downstream the water treatment unit in the water leading system.

15. The method according to claim 13, wherein the measurement unit is a separate entity independent of the treatment unit.

Description

[0029] Further details and advantages of the invention become apparent from the following description of specific working examples, with reference to the figures. The figures show:

[0030] FIG. 1: a water leading system of a treatment unit according to a first embodiment of the invention;

[0031] FIG. 2: a water leading system of a treatment unit according to a second embodiment of the invention;

[0032] FIG. 3: a water leading system of a treatment unit according to a third embodiment of the invention;

[0033] FIG. 4 a spectrum of an UV extinction measurement of 2-phenoxyethanol;

[0034] FIG. 5: a linear fitting of a series of measurements of a an UV extinction measurement of 2-phenoxyethanol at a wavelength of 216 nm; and

[0035] FIG. 6: a linear fitting of a series of measurements of a an UV extinction measurement of 2-phenoxyethanol at a wavelength of 269 nm.

[0036] FIG. 1 shows a schematic illustration of a water leading system of a treatment unit according to a first embodiment of the invention.

[0037] The system comprises a water supply 10 at its upstream end, for example a water tap of a building, a main line 20, a water treatment unit 30 arranged at the main line 20, and a consumer 40, for example in the form of an interface for a handheld dentistry tool, at the downstream end of the water leading system.

[0038] A measurement unit 50 is arranged at the main line 20 between the water treatment unit 30 and the consumer 40. The measurement unit 50 is described in more detail below.

[0039] FIG. 2 shows a schematic illustration of a water leading system of a treatment unit according to an alternative embodiment of the invention.

[0040] In this embodiment, the measurement unit 50 is not arranged at the main line 20, but at a bypass line 70, which runs parallel to the main line 20 between the water treatment unit 30 and the consumer 40. Switch valves 71 and 72 are arranged at the branching points of the bypass line 70 for flow control.

[0041] A control unit, which is signal connected to the water treatment unit 30, the measurement unit 50 and, in the case of the embodiment of FIG. 2 also to valves 71 and 72, is now shown in the figures.

[0042] In the embodiments of FIGS. 1 and 2, an antimicrobial agent is added to the treatment water flowing through the water leading system in the water treatment unit 30. A preferred option for added antimicrobial agent is a combination of hydrogen peroxide and 2-phenoxyethanol. Together with the antimicrobial agent, an UV active marker substance can be added to the water in an amount that is proportional to the added amount of antimicrobial agent.

[0043] The measurement unit 50 comprises a UV-vis sensor in combination with a LED light source. The emission and detection ranges of the light source and the sensor can be adjusted to the absorption profile of 2-phenoxyethanol or the marker substance.

[0044] Also in the case of using, for example, HOCl, Cl.sub.2, or ClO.sub.2 as an antimicrobial agent, a UV-vis measurement can be used for direct detection of the antimicrobial agent, without using a marker substance. Suitable emission and detection ranges of the light source and the sensor can thereby range from 200 nm to 380 nm, preferably from 240 nm to 340 nm.

[0045] Suitable photo diodes for use in a measurement unit 50 of a treatment unit of the invention comprise, for example, SiC photo diodes, which can emit wavelengths between 220 nm and 360 nm.

[0046] Alternatively, the measurement unit 50 may comprise a NIR spectrometer, which is suitable, for example, to determine a concentration of hydrogen peroxide. A suitable measurement window may range from 850 nm to 1800 nm.

[0047] The measurement devices described above can be implemented into a treatment unit in a simple and cost efficient way. They enable a close control of an antimicrobial agent content in the treatment water, in the batch mode of FIG. 2 as well as in the inline mode of FIG. 1. Thus, it is possible to monitor whether a sufficient amount of antimicrobial agent has been added in the water treatment unit 30 at any time. This increases patient safety and is also suitable to relieve the doctor or dentist in the case of water contamination from the outside, for example, through legionella.

[0048] One embodiment of the invention comprises a two-point measurement. While requiring more hardware, such measurement may provide additional information and provides additional options for an automated adaption of added amounts of antimicrobial agent based on measurement values.

[0049] FIG. 3 shows a schematic illustration of an embodiment of the invention, which makes use of this embodiment. Generally, the design of this embodiment is similar to the design of FIG. 1, but a second measurement unit 60 is additionally arranged at the main line 60 between the (first) measurement unit 50 and the consumer 40. A section of the water treatment system between the measurement units 50 and 60 is exposed to waste heat from other components of the treatment unit (e.g. power electronics, servo motors), and germ growth can be enhanced in this section.

[0050] The measurement units 50 and 60 are both designed as described above in connection with the measurement unit 50 of FIGS. 1 and 2. Further, both measurement units 50 and 60 are equipped with temperature sensors for measuring the temperature of the treatment water.

[0051] The two-point measurement is not only suitable to monitor whether a sufficient amount of antimicrobial agent has been added in the water treatment unit 30 at any time, but further enables measuring changes in antimicrobial agent content between the measurement units 50 and 60. In the case of sensors that allow for measuring a hydrogen peroxide content, for example, a reduction in hydrogen peroxide content that may be due to oxidation of organic compounds can be detected. The concentration difference can be considered a representative value for the degree of contamination.

[0052] The control unit can be configured to adjust the amount of antimicrobial agent added to the treatment water in the water treatment unit 30 based on that information.

[0053] In one embodiment, the control unit can be configured to evaluate the antimicrobial contents and water temperatures measured at measurement units 50 and 60 such as to provide a prognosis of temperature-dependent germ growth, and adjust the amount of antimicrobial agent added to the treatment water in the water treatment unit 30 based on that information.

EXAMPLE 1

[0054] A concentration measurement of 2-phenoxyethanol based on UV extinction measurement is described.

[0055] The test was carried out using an UV spectrophotometer UV-16000PC. Hellma Analytics QS High Precision Cell 1 mm cuvettes were used. Probes comprised an aqueous antimicrobial agent solution, comprising a combination of hydrogen peroxide and 2-phenoxyethanol, and further comprising substances for inhibiting the formation of limescale.

[0056] A dilution series of ten different concentrations between 10 and 300 ppm was prepared from the solution. For these probes, extinction was measured in the spectrometer at a resolution of 1 nm over wavelengths between 200 nm and 500 nm. The 1 mm quartz cuvettes were cleaned with deionised water and isopropanol, and dried, between subsequent tests.

[0057] FIG. 4 shows a spectrum of an extinction measurement of a probe comprising 0.025% (250 ppm) of 2-phenoxyethanol. The spectrum shows two characteristic peaks at wavelengths of 216 nm and 269 nm.

[0058] The following Table 1 shows the extinctions measured at these wavelengths.

TABLE-US-00001 TABLE 1 Concentration 2- phenoxyethanol [ppm] Extinction at 216 nm Extinction at 269 nm 10 0.0622 0.0138 20 0.1138 0.0216 30 0.1723 0.0323 40 0.2178 0.0408 50 0.2741 0.0558 100 0.5352 0.0990 150 0.9162 0.1507 200 1.0707 0.1984 250 1.3152 0.2447 300 1.5582 0.2921

[0059] FIGS. 5 and 6 how a linear fitting of the two measurement series. The result is a linear relationship with a coefficient of determination (R.sup.2 value) of 0.9996 at a wavelength of 216 nm and 0.9997 at a wavelength of 269 nm. To meet quality standards for measurements of the kind, the coefficient of determination should exceed 0.9990. This is the case for both measurement rows.