Detecting instrument for liquid analysis

Abstract

The invention relates to a probe (100) for uninterrupted liquid analysis, comprising at least one probe (101) for measuring a spectral characteristic of a liquid (102) to be analyzed and a liquid-tight housing (110) for accommodating the at least one probe (101), the at least one probe (101) being accommodated in the liquid-tight housing (110), and the at least one probe (101) being accommodated in the liquid-tight housing (110) and the at least one probe (101) being accommodated in the liquid-tight housing (110). At least one window is provided in a wall (111) of the liquid-tight housing (110), through which window at least one detector (101) detects a spectral characteristic of the liquid (102) to be analyzed, the liquid-tight housing (110) being connected to a flow channel (115) through which the liquid (102) to be analyzed flows, and the at least one window (112) being directed towards the flow channel (115). According to the invention, the flow channel (115) is wound. External light is prevented from entering the flow channel (115) by the coiled channel.

Description

Technical Field

[0001] The present invention relates to a detector for continuous liquid analysis, having at least one detector for measuring spectral properties of a liquid to be analyzed and a liquid-tight housing for receiving at least one detector, wherein at least one detector is received in the liquid-tight housing, and wherein at least one window is provided in a wall of the liquid-tight housing, and at least one detector detects spectral properties of the liquid to be analyzed through the window, wherein the liquid-tight housing is connected to a flow channel through which the liquid to be analyzed flows, and wherein at least one window is directed towards the flow channel. Background Art

[0002] For continuous analysis of liquids (so-called on-line monitoring), flow-through cuvettes are known, through which liquids to be spectroscopically examined flow. These flow-through cuvettes are used, for example, in laboratories or technical schools for analyzing a liquid or the composition of a particular substance component during a continuous chemical process. Flow-through cuvettes are also used in the field of clarified water technology for continuously observing clarifying agents and clarified water.

[0003] The continuous observation of mine water presents a special case. Mine water exists in closed mines and is always maintained at the same level by means of pumps. If the level drops, the mine water will flow into the gradually emptying mine. If the level rises too high, the mine water will seep into the groundwater and carry groundwater with heavy metals from deeper rock layers there. The rebalancing of the mine water level is an eternal task. To ensure that no groundwater mixes with the mine water, the mine water and the adjacent groundwater are continuously analyzed. Chlorides, heavy metals, nitrates, and pollutants from special waste previously introduced into the mine reach the surface. Not all of the pollutants to be observed here are detectable by continuous spectroscopic analysis, but rather they are only detectable by spectroscopic methods that are very sensitive instrumentally (such as Raman spectroscopy). Here, the instrumental sensitivity of the measuring instrument and the very harsh conditions for monitoring mine water are challenging problems.

[0004] In order to monitor mine water online by means of Raman spectroscopy, it is necessary to direct a laser beam at the mine water to be monitored and measure the Raman emission reflected by the Raman effect. The intensity difference between the excited laser and the Raman emission reaches several orders of magnitude here. Since the Raman emission has a different wavelength compared to the wavelength of the excitation, the monochromatic laser scattering caused by particles can be separated from the Raman emission by means of a diffraction grating in the Raman spectrometer. Stray light (such as stray sunlight) in the wavelength range of the Raman emission can no longer be separated from the actual Raman emission. Therefore, it is necessary to make the mine water flowing through the Raman spectrometer flow in a state protected from external light. Another problem that arises is that the window separating the mine water to be examined from the Raman spectrometer either becomes algae-covered, turns yellow due to deposits from the water, or simply becomes completely opaque after a short time. The deposits can be iron oxides or other heavy metal oxides, calcium precipitates, and bacterial growth. Therefore, the instrument set must withstand the harsh conditions in the mine, guide the mine water through the window for the spectrometer in a state protected from external light, and the window must be able to be cleaned without damage and without manually cleaning the detector for this purpose, because the number of detectors in the mine area is so large that it is not possible to clean each detector or each Raman spectrometer in use during the time when vegetation or deposits occur.

[0005] A very similar situation with the appearance of algae and the appearance of deposits exists in the wastewater of agricultural operations, such as manure water, wastewater from fermentation wells in biogas production facilities, but also in the field of water management, such as the water circulation in industrial and municipal water purification facilities and industrial cooling towers, only a few examples are given here. The common point of these liquids to be continuously monitored is that they can cause the appearance of algae growth, bacterial growth, or the precipitation of substances. Within the framework of the present application, these liquids are referred to as liquids containing substances. Summary of the Invention

[0006] Therefore, the object of the present invention is to provide a detector for continuous liquid analysis that can withstand the harsh conditions in liquids containing substances and guide the liquid containing substances through the spectrometer in a state protected from external light and is easy to clean.

[0007] The object according to the invention is solved by a detector having the features according to claim 1. The dependent claims of claim 1 give further advantageous designs.

[0008] Thus, according to the concept of the present invention, it is stipulated that the flow channel is wound. It has been surprisingly confirmed that, on the one hand, the wound shape of the flow channel enables the laser penetrating into the liquid, for example, to be retroreflected in a sufficient manner due to Raman emission, and on the other hand, it protects the window facing the flow channel from external light, especially from sunlight. By flowing along the winding part, strong eddies appear in the liquid, which slows down the algal growth or precipitation of substances present in the liquid containing substances.

[0009] The detector designed in this way is suitable for different types of spectral inspections. Here, it refers to all types of optical spectra, such as ultraviolet / visible light spectra, infrared / near-infrared spectra, measurement of light scattering, polarized light, and measurement of refractive index. The detector with a wound flow channel is particularly suitable for online monitoring of spectra by Raman spectroscopy. For this purpose, in the design of the detector according to the present invention, it is stipulated that the detector is a Raman spectrometer, and the laser beam irradiates into the liquid to be analyzed through at least one window.

[0010] A particularly suitable shape for the wound flow channel is a spiral shape. In addition to the spiral shape, there may also be other three-dimensional wound shapes of the flow channel. The exact shape of the spiral flow channel can be designed differently.

[0011] It is possible that the spiral shape of the flow channel has a varying winding part in its trend, where the varying winding part changes continuously. The concept of "winding part" should be understood in the sense of mathematical differential geometry. The winding part of the spiral depicts the torsion and curvature. The change in the winding part does not involve a uniform spiral, but a change in the curvature and torsion of the spiral. By changing the curvature, it is achieved that the fluid constructs a uniform parabolic velocity curve inside the inner diameter of the flow channel. This homogenization avoids the cavitation effect, which would erode the flow channel and the window facing the flow channel over time. The algal growth and precipitation of dissolved substances are also slowed down.

[0012] It is possible that the spiral shape of the flow channel has a constant diameter of the spiral in its trend of the number of turns changing along its axis. In this design, the liquid flowing through the flow channel flows with an increasing number of turns along the spiral axis per unit time. The liquid is thereby accelerated radially.

[0013] In another advantageous design of the flow channel, it is possible that the spiral shape of the flow channel not only has a changing number of turns along its axis, but also has a changing diameter of the spiral. This design exacerbates the radial acceleration effect of the liquid flowing through the flow channel. The acceleration effect has a strong counteraction on the algal growth and precipitation of dissolved substances. In the design of the flow channel, it is also possible that the spiral shape of the flow channel has a constant number of turns along its axis when the diameter of the spiral changes. Similarly, the radial acceleration during inflow is exacerbated by this shape.

[0014] In a particular design of the present invention, it may be provided that both the spiral diameter and the winding part vary. It is also possible that the spiral shape of the flow channel (115) has not only a varying number of turns along its axis (A), but also a varying diameter (dH) of the helix (H).

[0015] In order to definitely exclude external light, the winding part of the flow channel has at least half a turn. Thus, the spiral shape of the flow channel may include between 0.5 turns (180°) and 6 turns (1080°). More turns can be constructed. However, when the lower flow pressure is between 1 mBar and 50 mBar, there is an excessive pressure loss for the uniform flow in the flow channel.

[0016] In order to be able to use the detector for mine water, the diameter of the flow channel should not be too small so that the pressure loss is not too large and so that the flow channel can be cleaned. It has been proven advantageous that the ratio of the diameter to the length of the flow channel is between 0.5% and 5%, and the diameter of the flow channel is between 2 mm and 2 cm. For the viscosity of mine water, these values are conducive to avoiding algae growth and precipitation, and on the other hand, conducive to achieving easy flowability.

[0017] Nozzles are provided to flow into the flow channel for cleaning the flow channel, and the cleaning liquid can flow into the flow channel through the nozzles. The detector can thus be connected to a clear water hose, which regularly passes clear water through the nozzles through the flow channel, or passes the cleaning liquid through the flow channel. A remotely controlled valve can initiate the cleaning here. Description of the Drawings

[0018] The present invention is further illustrated by the following drawings. In the figures:

[0019] Figure 1 A sketch of the opened detector shown in a three-dimensional view;

[0020] Figure 2 The opened detector shown in a partially transparent view;

[0021] Figure 3 Shown in a top view Figure 1 of the opened detector;

[0022] Figure 4 Shown in another three-dimensional view which is partially transparent Figure 1 of the opened detector;

[0023] Figure 5 A view showing the principle shape of the flow channel in the detector. Detailed Description of the Invention

[0024] Figure 1Sketch of the opened detector 100 shown in a perspective view. The detector 100 shown in this embodiment consists of a liquid-tight housing 110 for accommodating the detector 101, wherein the detector 101 is arranged for measuring the spectral properties of the liquid 102 to be analyzed. The window 112 ( Figure 2 ) is located in the wall 111 of the liquid-tight housing 110, and the detector 101 detects the spectral properties of the liquid 102 to be analyzed through this window. For this purpose, the liquid 102 to be analyzed flows through a flow channel 115 provided in the housing, and the aforementioned window is directed towards the liquid 102 for the detector 101. The embodiment of the detector 100 shown here has exactly one detector 101. This detector is a Raman spectrometer, which projects a laser beam L through the window 112 into the liquid 102 to be analyzed and measures the spectrum of the generated Raman scattering here. However, it is also possible that there is more than one detector in the detector 100. These detectors can share a window 112 or each have their own window assigned to the corresponding detector. The embodiment of the detector 100 shown here is intended for deep mine water and to stay there for a long time in order to monitor the quality of the mine water. The task of this detector is to guide the liquid 102 to be analyzed past the window 112, while on the one hand, stray external light such as sunlight does not reach the detector, and on the other hand, stray laser light of the laser beam L also does not reach the outside. In order to shield stray light, it is provided according to the concept of the present invention that the flow channel 115 is wound. The wound shape of the flow channel 115 sends the laser beam L into a beam trap, and externally applied light such as sunlight cannot follow the winding and reach the detector. Since the detector should stay in the liquid to be analyzed (here mine water) deeply for a long time, a nozzle 120 is provided through which a cleaning liquid can flow into the flow channel. The cleaning liquid can be clear water under high pressure. However, it is also possible to mix a special cleaning fluid with a cleaning agent or a substance that chemically dissolves dirt, such as a strongly oxidizing mixture (such as hypochlorite or peroxide).

[0025] Figure 2 Shown in a partially transparent view Figure 1 of the opened detector. In this view, the window 112 in the wall 111 of the housing 110 is visible, which leads from the interior space of the detector 100 to the wound flow channel 115 of the detector 100. In addition to the window 112 shown through the transparent display, the nozzle 120 through which the cleaning liquid can flow into the flow channel is also visible. The cleaning liquid flows in through the nozzle 120 and escapes through a small door through which the liquid to be analyzed flows into and out of the detector again.

[0026] To show the coiled characteristics of the flow channel, Figure 3 is shown approximately in a top view Figure 1 of the opened detector. The transparent two-dimensional illustration shown here shows the coiled flow channel 115 as a channel that seems to meander only in two dimensions. But in fact, the channel is helical and is constructed in this way with individual winding portions W( Figure 5 ).

[0027] From Figure 4 it can be clearly seen that the flow channel 115 is helical. Figure 4 is shown in another partially transparent three-dimensional view Figure 1 of the opened detector, so that the individual winding portions W as a three-dimensional path can be traced in the course of the flow channel 115. The nozzle 120 is located near the part of the detector 100 that houses the detector 101. A cleaning hose can be connected to the nozzle 120.

[0028] Finally, Figure 5 illustrates views of different in-principle shapes of the flow channel 115 in the detector 100. The flow channel 115 can have a uniform helical course as shown in subfigure a). In a uniform course, the winding pitch Δ between two winding portions is constant. The winding pitch is the path length along the axis A around which the winding portion W winds in the case of a complete 360° turn. In this course shape, the diameter dH of the helix or the diameter dH of each winding portion W is constant, and the helix H has winding portions that are constant in the sense of mathematical differential geometry.

[0029] Subfigure b) shows another possible course of the flow channel 115 in the shape of the helix H already shown here. In this course, the diameter dH of the helix or the diameter dH of each winding portion W is constant, yet the winding pitch Δ varies continuously, so that the first winding pitch Δ1 between two winding portions W is greater than the second winding pitch Δ2 between another two winding portions W. Here, the change of the winding portions of the helix H occurs continuously in the sense of mathematical differential geometry and does not change suddenly.

[0030] Subfigure c) shows another possible course of the flow channel 115 in the shape of the helix H already shown here. In this course, the diameter dH of the helix or the diameter dH of the successive winding portions is not constant but exceeds a minimum value. In contrast, the winding pitch Δ remains constant, so that the winding pitch Δ between two winding portions W remains the same. The change of the diameter dH of the helix or the diameter dH of the successive winding portions occurs continuously and does not change suddenly.

[0031] Finally, sub - figure d) shows another possible trend of the spiral H - shaped flow channel 115 already shown here. In this trend, the diameter dH of the spiral, or rather the diameter dH of each winding part W, is not constant, and the winding part pitch Δ is also not constant, such that the first winding part pitch Δ1 between two winding parts W is greater than the second winding part pitch Δ2 between another two winding parts W.

[0032] List of Reference Signs

[0033] 100 Detector

[0034] 101 Probe

[0035] 102 Liquid

[0036] 110 Housing

[0037] 111 Wall

[0038] 112 Window

[0039] 115 Flow channel

[0040] 120 Nozzle

[0041] A Axis

[0042] d H Diameter (spiral)

[0043] d s Diameter (flow channel)

[0044] Δ Winding part pitch

[0045] Δ1 Winding part pitch

[0046] Δ2 Winding part pitch

[0047] L Laser beam

[0048] W Winding part

Claims

1. A detector (100) for continuous liquid analysis, having - at least one detector (101) for measuring the spectral properties of a liquid (102) to be analyzed, and - a liquid-tight housing (110) for accommodating the at least one detector (101), - Among them, wherein the at least one detector (101) is accommodated in the liquid-tight housing (110), and wherein - at least one window (112) is provided in a wall (111) of the liquid-tight housing (110), and the at least one detector (101) detects the spectral properties of the liquid (102) to be analyzed through the window, - the liquid-tight housing (110) is connected to a flow channel (115) through which the liquid (102) to be analyzed flows, and - the at least one window (112) is directed towards the flow channel (115), characterized in that the flow channel (115) is coiled.

2. The detector according to claim 1, characterized in that the detector (101) is a Raman spectrometer, and a laser beam (L) is incident into the liquid (102) to be analyzed through at least one window (112).

3. The detector according to claim 1 or 2, characterized in that the flow channel (115) has a helical shape.

4. The detector according to claim 3, characterized in that the helical shape of the flow channel (115) has varying turns (W) in its course, wherein the varying turns (W) vary continuously.

5. The detector according to claim 3, characterized in that the helical shape of the flow channel (115) has a constant diameter (dH) of the helix (H) in the course of the number of turns varying along its axis (A).

6. The detector according to claim 3, characterized in that the helical shape of the flow channel (115) has a constant number of turns along its axis when the diameter (dH) of the helix (H) varies.

7. The detector according to claim 3, characterized in that the helical shape of the flow channel (115) has not only a varying number of turns along its axis (A), but also a varying diameter (dH) of the helix (H).

8. The detector according to claim 3, characterized in that the helical shape of the flow channel (115) includes between 0.5 turns (180°) and 6 turns (1080°).

9. The detector according to any one of claims 1 to 8, characterized in that The ratio of the diameter (d S ) to the length of the flow channel (115) is between 0.5% and 5%, and the diameter (d S ) of the flow channel (115) is between 2 mm and 2 cm.

10. The detector according to any one of claims 1 to 8, characterized in that a nozzle (120) feeds into the flow channel (115), and a cleaning liquid can flow into the flow channel (115) through the nozzle.

Images