EP0981121A2 - Fluiddetector - Google Patents

Abstract

The arrangement has at least one light conducting body (20) with at least one surface section (45) for contact with a liquid, especially precipitation, that is arranged relative to a light source (36) so that the light can be totally reflected at the surface section and at least one light detector (37) that can be positioned above the surface section in light conducting connection with the light source..

Description

The invention relates to a liquid detection device, in particular a precipitation reporting device, such as one Rain detector.

Liquid detection devices can for example Recording of precipitation situations as stationary rain detectors be used in the home and garden area to a to control automatic irrigation system. An institution This type should, for example, be able to persistent thick fog or other humidifying precipitation emit one or more precipitation signals at whose reception the irrigation system is switched off can prevent the monitored area from over-humidifying avoid and to save water. There should be one or more Dry signals are given if none for the desired one or necessary humidification sufficient precipitation goes down, so the irrigation system keeps it moist can take over.

The invention has for its object, one in particular usable as a stationary precipitation indicator To create liquid detection device. In particular, should the facility will be able to make a reliable distinction between precipitation and dry conditions to enable.

This object is achieved by a liquid detection device with the features of claim 1.

The particularly usable as a rain detector and because of this preferred application also as a precipitation indicator designated liquid detection device has at least one Light source and at least one light guide body made of a material that is transparent to the light from the light source consists. The light guide body has at least one surface section, for contact with the liquid, in particular the liquid precipitation substance and which is arranged relative to the light source, that the light from the light source at the surface portion is totally reflectable if suitable at the surface section Total reflection conditions are present. Furthermore, at least a light detector is provided over the surface portion in light-conducting connection with the light source is feasible.

So it becomes an optical liquid or precipitation sensor created where liquid, especially precipitation the light conduction between the light source and the light detector changes significantly. As long as the Surface section is essentially dry because e.g. there is no or insufficient precipitation, limit at the surface section the optically dense material of the for example made of glass or transparent for visible light Plastic existing light guide body with a typical Refractive index significantly greater than 1, for example about 1.5, and the gaseous ambient atmosphere with a typical refractive index on the order of 1 to each other. Is the surface section with respect to that of the Incident light source from the side of the light guide body Light compared to the central direction of incidence of the incoming line at an angle of incidence that is greater than that material-specific critical angle of total reflection is so the light is totally reflected at the surface section and cannot leave the light guide at this point, but is totally reflected inside the body. At this Dry situation, one or more of the dry state assigned dry signals. On the other hand, if the surface section especially due to precipitation Change water in contact, especially wetted by it due to the higher refractive index of the Water, typically about 1.3, the reflection ratios on the surface section such that no total reflection takes place, but that light from the surface section exits the light body, that is, it is decoupled from it. This wetting situation, known as the precipitation situation leads to the delivery of one or more liquid or Precipitation signals. After sufficient drying of the The surface section is then again the conditions for Total reflection before and a dry signal can be given become. Further training is shown below using the example of a Precipitation detector explained, the term "precipitation" may also stand for other liquids.

Can be used to detect precipitation on the surface section both the one transmitted or transmitted through it Light intensity, as well as the total reflected intensity, either alternatively or in combination. In a preferred embodiment, the light detector arranged to the surface section such that substantially only light totally reflected from the surface section the light source is detectable. A direct light guide between source and detector is expediently prevented. The exclusive use of the reflected intensity for One of the reasons why precipitation detection is advantageous is because the light detector then, for example, within the Lichtleitkörper and / or on the solid side of the surface section can be arranged, which is compact on the one hand Design allows and on the other hand the protection of the Light detector from moisture and damage easier.

Embodiments are particularly preferred in which Light path between light source and light detector several, in particular two surface sections arranged at an angle to one another are provided, which are relative to the light source and are arranged to each other so that the light the light source can be totally reflected via it to the light detector is. Because of the possible at least two Redirection between light transmitter or light source and light receiver The differentiation reliability increases between dry state and precipitation state considerably, because only then sufficient light intensity at the light detector occurs when all totally reflective arranged in the light path Surface sections due to drought Total reflection conditions are present.

Embodiments are particularly preferred in which at least two surface sections are arranged in such a way that the light of the light source by total reflection by more than 90 °, in particular essentially by 180 °, is deflected. This enables a compact structure, for example Light source and light detector close to each other Side of the light guide body can be arranged, while the wetting surface sections in the area of the opposite Page can be arranged. The light guide can for example with a circular cone-shaped part have an opening angle of approx. 90 ° at which diametrical opposite, curved, totally reflecting surface sections are arranged, which have a certain light focusing effect can exercise. It is also possible that the light guide body at least two at an angle of 90 ° to each other has standing, flat surface sections and for example is in the form of a roof edge prism.

It can be any suitable light source or combination of Light sources and any suitable, based on the light of the light source responsive light detector can be used. Especially inexpensive, reliable working and energy consumption favorable embodiments are characterized by that the light source at least one, preferably exactly one Has light-emitting diode and / or that the light detector at least one, preferably only one, photodiode. On Energy saving effect can still be achieved if a device for discontinuous operation of the light source, in particular for pulse operation, is provided, wherein if necessary, the pulse interval can be adjustable. The time interval between successive, possibly very short Light emissions can be in seconds or minutes, for example at about 10 or 30 or 60 seconds or more. Particularly correspondingly economical embodiments can advantageously work independently of the network and for example about batteries, accumulators and / or photovoltaic elements be supplied with electrical power. A network dependent Care is alternatively or additionally possible.

In preferred embodiments, there is at least one precipitation reservoir intended to collect precipitation, with a precipitation reservoir preferably attached to one Surface section adjoins. This can increase the reliability the facility increased or false reports largely be avoided, because a signal change from dry if interpreted appropriately, precipitation is only adequately filled precipitation reservoir take place, so that short showers, which may not be productive, do not constitute a precipitation situation can be interpreted and not for example Stop a controlled irrigation system. It is preferred if the precipitation reservoir is used as a capillary reservoir is formed in which a capillary forces Filling the reservoir and / or holding liquid in the Effectively effect and / or promote reservoir. The reservoir can be designed so that it is only in precipitation of a certain intensity and / or that after decay of the precipitation, the filling still has a certain delay remains until the contents of the reservoir evaporate, so that only significant, relatively long phase changes between Precipitation and drought lead to signal changes.

In preferred embodiments, at least one is between the surface portion and a counter surface formed Gap provided in the, possibly by capillary forces supports, collect precipitation and over a period of time can hold. The counter surface can, for example, by suitable coloring and / or surface design, such as Roughening or gradation, as an absorption surface for the Light of the light source should be formed so that when it is no longer available the total reflection entering the liquid-filled gap Light intensity essentially from the counter surface is absorbed and also as scattered light not to the light detector can reach.

Embodiments with adjustable ones are particularly advantageous Response threshold, at which the precipitation intensity, where the sensor should respond, by the user is definable. In embodiments with a precipitation reservoir this can be realized particularly simply by that the precipitation reservoir has an adjustable absorption capacity has, preferably the shape and / or size of the adjustable at the surface section adjacent gap is.

Further measures to improve the rain detector, especially its responsiveness, are related explained in more detail with preferred embodiments. In particular, the device can collect catchment and / or collecting the precipitation liquid-conducting via a precipitation feed device with the surface section, in particular the precipitation reservoir, are connected. This makes it possible relatively large collecting area for the precipitation to be provided while for the detection of precipitation required area of the surface section in contrast, can be very small. A corresponding funnel effect can be on a Housing of the rain detection device can be achieved, for example through suitable water channels on one Exterior of the housing, the water channels vertical Corrugations on an upper section of a housing and / or obliquely to the vertical on the circumference of a housing funnel-shaped can include converging collective tours.

Furthermore, in connection with the embodiments retention means for retaining the precipitation explained in more detail on the surface section, in particular in the precipitation reservoir be provided, making it in particular a suitable delay time between Stop precipitation and emit a dry signal adjust. For example, in a gap provided at the surface section, for example web-like elements additional wetting areas provide for the precipitation that is draining off Appropriate delay or evaporation of the reservoir content. The Elements can also be used as spacing elements for adjustment and maintaining an appropriate gap geometry be used.

Preferred embodiments work according to the invention Rain detectors are characterized by a modular Structure with several functional, detachably connectable Share out. In particular, one, preferably cartridge-like molded, especially moisture-proof lockable, Detector upper part can be provided, preferably in one cylindrical, open top housing with larger Diameter can be inserted in sections such that between an outside of the upper part of the detector and one Housing wall of the basic housing at least one inlet gap is formed, for example a circumferential annular gap be or can be formed by several ring segments. The outside of the upper part of the detector protruding from the lower part can be used for large-scale precipitation collection be, the collected precipitate through the inlet gap in the otherwise largely protected from the outside Interior of the basic housing is running.

The light source, control electronics for the light source, the light detector, evaluation electronics for the light detector and the light guide body can in and / or in a housing part of the signaling device, in particular the Detector top, that the surface section forms part of the outer surface of this part. In particular the light guide body can have a lower end of the upper part of the detector form, preferably at least one surface portion essentially as an extension of the outer surface the upper part of the detector is arranged so that on the outside liquid from the upper part of the detector to the surface section flows.

Such a detector top, which preferably also one especially watertight lockable receiving space for an energy supply for the control and evaluation electronics can have, not only in rain detectors according to the invention used, but also for example as a self-sufficient liquid level detector in one Container, pond or the like. With this application, measures can be taken for supplying, holding and / or discharging liquid and / or a liquid reservoir can be dispensed with. On Fluid signal can be given when the Surface of a liquid to be monitored down to the Area of a surface section or over the surface section has risen.

The upper part of the detector can be used to create a rain detector and the basic housing is preferably detachable without tools be connectable, preferably the upper part of the detector fixable in the basic housing and / or with the basic housing, for example by means of a manual actuable union nut, can be screwed. The The basic housing can have a gap-counter surface Have counterparts, so that the setting of the position of the Detector upper part in the basic housing the shape and / or size of the gap serving as a precipitation reservoir is adjustable.

The detector can be located in the area to be monitored, for example by means of a screw-on mandrel or the like, by means of feet or other fastening devices be fixed in a stationary position. The signals for Can display dry condition or rainfall condition via cable or wirelessly, for example via an integrated one Infrared transmitter, for further processing of the Signals are given to the outside.

These and other features go beyond the claims also from the description and the drawings, wherein the individual features individually or separately several in the form of sub-combinations in one embodiment of the invention and in other fields be and can represent advantageous designs.

Fig. 1

einen Längsschnitt durch eine erste Ausführungsform eines erfindungsgemäßen Regenmelders,

Fig. 2

eine teilweise geschnittene Seitenansicht des Melderoberteils einer Ausführungsform ähnlich der nach Fig. 1,

Fig. 3

einen Querschnitt entlang der Linie III-III in Fig. 1,

Fig. 4

eine schematische Darstellung der Lichtleitverhältnisse im Trockenzustand,

Fig. 5

eine schematische Darstellung der Lichtleitverhältnisse bei Niederschlag und

Fig. 6

einen Längsschnitt durch eine andere Ausführungsform eines Regenmelders.

Embodiments of the invention are shown in the drawings and are explained in more detail below. The drawings show:

Fig. 1

2 shows a longitudinal section through a first embodiment of a rain detector according to the invention,

Fig. 2

2 shows a partially sectioned side view of the upper part of the detector of an embodiment similar to that of FIG. 1,

Fig. 3

2 shows a cross section along the line III-III in FIG. 1,

Fig. 4

a schematic representation of the light guide conditions in the dry state,

Fig. 5

a schematic representation of the light guide conditions during precipitation and

Fig. 6

a longitudinal section through another embodiment of a rain detector.

The longitudinal section in Fig. 1 shows a first embodiment one stationary on the surface of the earth, for example in a lawn, preferably installed vertically, liquid or Rain detector 1, the three by hand without the aid has assemblies that can be assembled by tools. In a in essentially cylindrical base housing 2 made of thermoplastic Plastic is also called a measuring cartridge, Cartridge-shaped detector top 3 from above used centrally and held in place. One in cross section cross-shaped mandrel 4 for insertion into the ground by means of a union nut in the form of a plug-in stop serving screw plate 5 to a lower external thread attachment 6 of the basic housing 2 screwed.

The basic housing 2, which is cylindrical in cross section (FIG. 3) on its side walls diametrically opposite the central axis 7, axial guide slots 8. In the floor area centric one essentially in the form of an upward expanding, conical funnel-shaped funnel body 9 provided that the radial holding webs 10 with the Side wall of the basic housing 2 is connected and one has central, lower passage opening 11, via the the interior of the basic housing 2 with the liquid Area of the mandrel 5 is connected. On the essentially truncated cone-shaped inside of the funnel are in the lower Area directly above the central opening 11 around the circumference of the funnel distributes a plurality of web-shaped projections 12 intended.

The measuring cartridge 3 has an injection molded plastic housing 15 with an approximately cylindrical upper section 16, which follows below an intermediate section that tapers conically downwards 17 and connect a cylindrical subsection 18. A circular lower front opening of the housing 15 is by a light guide explained in more detail later 20 sealed watertight. The opposite open End of the housing 15 is by a screw cap 21 watertight sealable, the internal thread in one external thread of the upper section 16 engages and the inside of which rests on a sealing ring 22 which is in an annular groove is inserted on the outer circumference of the upper section 16 is. Approximately in the middle between the front openings of the Housing 15 is an intermediate wall running transversely to axis 7 23 provided that the interior of the housing 15 in an upper receiving space 24 for batteries or accumulators and a cylindrical, lower receiving space 25 for the Electronics of the rain detector divided.

Are on the outside of the housing 15, in one piece with this axially extending, radially projecting longitudinal webs 26 arranged diametrically to the central axis 7. In the area of Bottom end of the longitudinal webs are centering tabs 27 in shape of extensions of the longitudinal webs projecting radially outwards provided, the top of a centering tab, as shown in Fig. 1, approximately flat or, as shown in Fig. 2, be provided with a support recess 28 which is open at the top can. The radially outer edges of the centering tabs 27 form at least when the measuring cartridge 3 is inserted into the Basic housing 2 a lateral guide within the guide slots 8. The measuring cartridge is in the axial direction Basic housing 2 inserted until the light guide 20 on the one piece with the funnel body 9, as Spacers acting projections 12 of a counter body forming funnel body 9 rests. Then the cartridge 3 by means of which can be screwed onto the upper opening of the basic housing 2 Union nut 29 and by means of a Underside of the union nut and on the centering tabs 27 supporting, pressure-loaded spring 30 pressed down. The lateral longitudinal webs 26 of the cartridge are tight in the inner recess of the union nut 29 fitted and ensure a wobble-free coaxial fit of the measuring cartridge 3 in the basic housing with screwed union nut and tensioned compression spring 30.

The measuring cartridge 3 takes one in its lower receiving space 25 built on a board 35 and symbolized by this Control and evaluation electronics that have a light source in Form controls a light emitting diode 36 and the one of one Light detector in the form of a photodiode 37 generated detector signal evaluates. In the sectional view of FIG. 3 appears the housing 15 of the cartridge 3 in two parts circuit board 35 clamped between double webs 38. It is also possible and preferred, the cartridge housing in one piece run and the board with the light source attached to it 36, the detector attached to it, and the im following light guide 20 to be explained, from below in insert the cartridge housing. The electrical energy for Light source, light sensor and for control and evaluation electronics 35 is used by in the receiving space 24 Batteries or accumulators provided. Alternatively or in addition to the off-grid supply, a wired supply by a with the rain detector 1 connected supply device. To reduce the Energy consumption, especially for those working off-grid Embodiments, the light emission of the light source 36 be pulsed, preferably with a small clock ratio of for example a pulse per minute.

The one made of glass or transparent to the light from the light source 36 Plastic existing light guide body 20, the schematic 4 and 5 is also essential Element of the precipitation indicator device 1. It has an in Fig. 1 upper, arranged coaxially to the axis 7 cylindrical Section 39, in which diametrically to the axis 7 two blind holes Recesses for light source 36 or light detector 37 are provided. Between these are preferably Means direct light conduction between light source and prevent light detector, for example an opaque one Partition that in a central recess of the Light guide body is arranged. At the cylindrical section 39 closes at the bottom a circular cone Section 40, whose rounded cone tip when assembled Detector down in the area of the opening 11 of the Counter body 9 protrudes. The essentially conical, facing the conical inside of the counter body 9 Surface 41 of the light guide body stands with one through the Height of the spacer elements 12 determined, small distance parallel to the conical surface and as a conical recess shaped counter surface 42 of the counter body 9 opposite. The Cone surface 41 and the counter surface 42 close narrow, approximately conical sections 43, 44 between them.

The functioning of the rain detector is now in 4 and 5, with FIG. 4 a dry state and Fig. 5 shows a state of precipitation shows. When the rain detector is operating, it radiates preferably light source 36 driven in pulse mode Surface section 45 of the conical surface 41 in the area of Column 43 on. The light falls through that through one Vertical defined on the surface section 45 Incidence slots at an average angle of incidence of approx. 45 ° on. In dry weather or very little rainfall the gap 43, as shown in Fig. 4, is filled with air. In particular, because of the alignment of the surface section diagonally down there is no precipitation directly meet these surfaces. With air-filled gap 43 on the interface 45 between the optically denser light guide body 20 and the optically thinner medium air in the gap 43 the light on the at an angle of 45 ° to axis 7 Interface 45 totally or at least to a very high one Portion reflected. The reflected light is reflected on the surface section 46 opposite cone axis 7 the conical surface 41 deflected at the gap 44. Is this too Gap filled with air, which is the rule in dry weather, then total reflection occurs again in the prism body Redirecting light to detector 37 while practical no light leaves the light guide body in the direction of the gap 44.

In this represented by the double arrows in Fig. 4 Detector 37 registers light deflection by a total of 180 ° in dry weather and with the light source switched on strong light and the electronics 35 gives one "Dry" message off or goes into a "dry" switching state with regard to an external device, for example one automatic irrigation system.

When precipitation sets in, it turns up and on the projecting beyond the base housing 2 of the Cartridge 3 down. Between the outside of the conical Intermediate section 17 of the cartridge 3 and the inside of the The union nut is an inlet gap 50 in the form of an annular gap free, due to the liquid precipitation, such as rainwater, down into the cartridge housing 15 Interior of the basic housing except for the extension of the lower surface portions 45, 46 thereof can flow. The collection and collection of precipitation can are supported by suitable fall arrest devices which Rainwater supply devices with the Surface sections 45, 46 are connected. In the case of Fig. The embodiment shown in Figure 2 is on the outside of the top section 16 of the cartridge 3 a substantially vertical Alignable, fine corrugation 51 provided that a variety of water channels directed downwards and which ensures that only small drops form that run down quickly. About in the amount of Top edge of the base case 2 or slightly above is for each of the surface portions 45, 46 a pair of in Direction of the assigned surface section converging Collection guides 52 are provided for incoming water, the guiding surfaces projecting slightly from the outer surface of the housing in the form of opposing four-part spiral sections are trained. This creates a funnel effect and collection of the liquid running off at the upper section in the direction of the surface sections 45, 46 or this adjacent column 43, 44 reached and the filling of the Column can be accelerated.

Is at least one of the two as a precipitation reservoir serving column 43, 44 due to incoming rainwater Filled with water, the one described above does not apply Total reflection leading interface situation and it finds no or no significant total reflection takes place. Instead, as shown in Fig. 5, the light emerges from the Prism body 20 through the surface 45, and possibly a Residual portion through the surface 46, and is by the liquid-filled gap passed to the counter body 9, the absorbs the light. Especially if both columns 43, 44 are filled with liquid, comes on when the light source lights up 36 practically no more light intensity to the detector 37. In this case, the electronics report the "rain" state.

The light guide body 20 is due to its tapered Shape and the support on the spacers 12 of the counter body 9 self-centering. The spacers 12 are on the lower ends of the gap regions 43, 44 which of the Light source 36 illuminated and monitored by the detector 37 are provided. In addition to ensuring a precise Meet the distance between prism body 20 and counter body 9 the spacers 12 yet another function by the water in the gap at the points of the spacer bars cannot flow directly downwards and after the end of precipitation the gap areas relevant for the detection 43, 44 stay filled with water for longer. In the circumferential direction to the side of the gap areas 43, 44 are no spacer webs present or they are at least interrupted to work on them Places to allow unimpeded drainage of water so that the water is not in the entire cone of the Counter body jams. Furthermore, the surface areas of the Counter body 9 laterally irradiated or monitored Gap sections 43, 44 graded and / or further from the light guide 20 be removed to rinse in this area of dirt particles. The excess Water and possibly carried dirt can through the central Passage opening 11 of the counter body down and discharged to the outside via a lower opening in the basic housing become. Spacers can be used for a better fit of the Prismatic body on the counter body also in one example 90 ° rotated position then essentially no retention function for the optical water detection unless there would be a crossed optical arrangement with two light sources and two detectors used.

The surface sections relevant for the detection Columns 43, 44 assigned to 45, 46 serve as a precipitation reservoir, through which the detection reliability of the Facility can be increased. Because a precipitation display is only released when the amount of precipitation sufficient to fill the column 43, 44 and a dynamic Balance while maintaining the filling between flowing precipitation and flowing and / or evaporating To maintain rainfall. If not a new one If water flows in, the water in the crevices becomes still held in the crevices by capillary forces and gradually evaporate, the delay time up to which the gaps are filled with air again, essentially through the Geometry of the gap arrangement, in particular the gap width, and determines the weather (humidity, temperature) is. Accordingly, by adjusting the gap geometry, for example by choosing a counter body with higher or flatter spacers, the capacity of the capillary reservoir and thus both the response threshold for a Precipitation signal, as well as the delay time until Dry signal can be set after a precipitation.

Another using the same detection principle, too can be equipped with a screw-on setting mandrel Embodiment of a rain detector 55 is shown in FIG. 6. This embodiment also has a measuring cartridge 56, which in a approximately cylindrical base housing 57 is inserted from above. However, it is not, as in the embodiment according to Fig. 1, fixed by a union nut, but axially inserted into the basic housing 57 and clamped. The Insertion position, and thus the gap width between the Light guide body 58 and the counter body 59 formed column 60, 61 in the axial extension of light source 62 or Light detector 63 can be adjusted via the insertion depth. At the embodiment shown is through Stop elements defined that the insertion depth for the Limit cartridge 56. Also reached in this embodiment Precipitation, which is on the top and the side surfaces the measuring cartridge protruding beyond the basic housing precipitates through an annular gap 64 except for those adjacent to column 60, 61 for total reflection surface sections 65 provided for light, 66 of the light guide body 58.

It is understood by those skilled in the art that for the function of the Detector the optical conditions described as an example only on those irradiated by the light source or by the Detector monitored surface sections 45 and 46 of the Lichtleitkörper must be present so that this many can have different shapes and that even one suitable surface section is sufficient or more than two can be provided. Total reflection can also be from 45 ° deviating angles of incidence occur. The angle of incidence should be chosen so that when the surface section is dry Total reflection occurs while in contact with precipitation Light is coupled out of the light guide body.

Claims (16)

Liquid detection device, in particular rain detector (1; 55), with at least one light source (36; 62), at least one light guide body (20; 58), the at least one for contact with liquid, in particular Precipitation provided surface section (45, 46; 65, 66), which is relative to the light source is arranged that the light of the light source on the Surface section is totally reflectable, and with at least one light detector (37; 63), which over the Surface section in light-conducting connection with the Light source can be brought. Liquid detection device according to claim 1, characterized characterized in that the light detector (37; 63) such to the surface section (45, 46; 65, 66) is that essentially only at the surface section totally reflected light from the light source is detectable and / or that in a light path between the light source (36; 62) and light detector (37; 63) at least two, preferably only two surface sections (45, 46; 65, 66) are provided, which are arranged such that Light from the light source over the at least two surface sections is totally reflectable to the light detector. Liquid detection device according to one of the preceding Claims, characterized in that at least two surface sections (45, 46; 65, 66) such are arranged so that the light from the light source Total reflection by more than 90 °, especially by approx. 180 °, is deflected and / or that the light guide (20) has a circular cone section (40), preferably with an opening angle of approx. 90 °. Liquid detection device according to one of the preceding Claims, characterized in that the Light source at least one light-emitting diode (36; 62), preferably has only one light emitting diode and / or that the light detector has at least one photodiode (37; 63), preferably has only one photodiode. Liquid detection device according to one of the preceding Claims, characterized in that a Device (35) for discontinuous operation, in particular for pulse operation, the light source (36; 62) is provided. Liquid detection device according to one of the preceding Claims, characterized in that they are at least a liquid reservoir, in particular a Precipitation reservoir (43, 44; 60, 61) has to the preferably at least one surface section (45, 46; 65, 66) directly adjacent, preferably that Liquid reservoir (43, 44; 60, 61) as a capillary reservoir is trained. Liquid detection device according to one of the preceding Claims, characterized in that they at least one between the surface section (45, 46; 65, 66) and a counter surface (42) formed gap (43, 44; 60, 61), which preferably has a liquid reservoir, especially a precipitation reservoir forms, preferably with the counter surface (42) as Absorbent surface designed for light from the light source is. Liquid detection device according to one of the preceding Claims, characterized in that they are a has adjustable response precipitation intensity. Liquid detection device according to one of claims 6 to 8, characterized in that the liquid reservoir, especially the precipitation reservoir has adjustable capacity, preferably the shape and / or size of the gap (43, 44; 60, 61) is adjustable. Liquid detection device according to one of the preceding Claims, characterized in that collecting agents (51, 52) for collecting and / or collecting Precipitation is provided via a precipitation feed device (50; 64) liquid-conducting with the surface section (45, 46; 65, 66), in particular the precipitation reservoir (43, 44; 60, 61) are. Liquid detection device according to one of the preceding Claims, characterized in that on one above the surface section (45, 46; 65, 66) arrangeable outer surface of the liquid detection device an essentially vertically orientable corrugation (51) is provided, preferably above of the surface section (45, 46; 65, 66), funnel-like in the direction of the surface section converging collecting tours (52) for precipitation are provided, preferably in the form of at one Outer surface of the liquid detection device at an angle to Vertical, spiral section-shaped guide bars (52), which is preferably below the catcher (51) can be arranged. Liquid detection device according to one of the preceding Claims, characterized in that restraining means (12) to retain liquid, especially of precipitation on the surface section (45, 46; 65, 66), in particular in the liquid reservoir (43, 44; 60, 61), are provided, preferably the retention means at least one in a liquid reservoir (43, 44; 60, 61) arranged, wettable Have element, preferably at least one die Spacer element determining the shape and / or size of the gap (12). Liquid detection device according to one of the preceding Claims, characterized in that they preferably cartridge-like, upper part of the detector (3; 55) has that in a, preferably cylindrical, above open basic housing (2; 57) with a larger diameter is so insertable that between an outside of the Detector upper part and a housing wall of the basic housing at least one inlet gap (50; 64), preferably in Form of an annular gap, is formed, preferably the upper part of the detector (3; 55) and the basic housing (2; 57) can be connected to one another without tools, in particular can be clamped together and / or manually screwable. Liquid detection device according to one of the preceding Claims, characterized in that the Lichtleitkörper (20; 58) a lower end of the Detector upper part (3; 55) forms, preferably at least one surface section of the light guide body essentially in extension of an outer surface of the Detector top is arranged and / or that a Counter surface (42) of the gap having counter body (9; 59) assigned to the basic housing (2; 57), in particular is integrally formed with this. Liquid detection device according to one of the preceding Claims, characterized in that the Light source (36; 62), preferably control electronics (35) for the light source, the light detector (37; 63), and preferably evaluation electronics (35) for the Light detector, preferably water-protected, in one common housing (15), especially in the upper part of the detector (3; 55) are housed, preferably the light guide body (20; 58) in such a way on and / or in the Housing is arranged that the surface section forms part of the outer surface of the housing and / or that a housing, in particular the upper part (32), a preferably watertight lockable receiving space (24) for a grid-independent energy supply having. Liquid detection device according to one of the preceding Claims, characterized in that one, preferably detachably with a housing (2; 57) of the liquid detection device connectable, device for stationary attachment of the liquid detection device is provided on the surface of the earth, preferably in Form of a screw-in plug-in mandrel (4).

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