EP0910809A1

EP0910809A1 - Rain gauge

Info

Publication number: EP0910809A1
Application number: EP97931838A
Authority: EP
Inventors: Joel Panhelleux
Original assignee: Perrot SA
Current assignee: Perrot SA
Priority date: 1996-07-08
Filing date: 1997-07-01
Publication date: 1999-04-28
Also published as: WO1998001775A1; FR2750772B1; FR2750772A1; AU3545297A

Abstract

The invention discloses a rain gauge comprising a first device for collecting (5) rain water, mounted tilting between two stable positions for delivering, with each tilt, a preset amount of rain water and a second collecting device (10), mounted tilting to collect at least the amount of water delivered after each tilt of the first device (5), the threshold of the second device (10) tilting corresponding to an amount of water greater than that which is required for the tilting of the first device (5), and means (20) for counting the number of tilts of the two devices (5, 10) to calculate the duration and the amount of rain fallen during a precipitation.

Description

RAIN GAUGE

The present invention relates to a rain gauge intended to measure the precipitation of atmospheric water in a meteorological or bioclimatological station, for example.

In general, current rain gauges are based on the use of a rainwater recovery device which is pivotally mounted to discharge, at each tilting, a determined quantity of rainwater which is recovered between two successive changes. From this amount of rainwater which defines the tilting threshold of the recovery device and the number of tilting of the latter, it is thus possible to determine the amount of water dropped and the duration of a precipitation.

The object of the invention is to improve the precision of the measurements obtained from a rain gauge of the aforementioned type by taking into account in particular the degree or the intensity of the precipitation. To this end, the invention provides a rain gauge comprising a first device for recovering rainwater from atmospheric precipitation, mounted tilting between two positions to evacuate at each tilting, a determined quantity of rainwater which is recovered between two successive changes, rain gauge which is characterized in that it comprises a second recovery device mounted to tilt to recover at least the quantity of water discharged after each change of the first recovery device, the changeover threshold of this second device corresponding to a quantity of water which is greater than that necessary for the tilting of the first device, the rain gauge also comprising means for counting the tiltings of the two devices to determine the duration and the amount of rain fell during precipitation.

According to another characteristic of the invention, the rain gauge comprises a fixed inlet funnel for receiving and directing rainwater to the first recovery device, and the second recovery device can also be directly fed from this funnel inlet when the level of rainwater in the latter exceeds a determined threshold, especially in heavy rain. Advantageously, the rainwater discharged after each tilting of the first recovery device is poured into a fixed intermediate funnel which feeds the second recovery device, and the inlet funnel and the intermediate funnel can communicate with one another. other by a bypass duct.

Generally, each recovery device comprises a double bucket, so that, for one position of each recovery device, one bucket is in a filling position while the other bucket is in a drainage position , and vice versa for the other position of each recovery device.

According to one embodiment, the means for counting the tiltings of each device for recovery include a fixed position sensor associated with each bucket of the double buckets, a counter connected to the two sensors of each recovery device, and a control and measurement unit connected to the two counters of the two recovery devices on the one hand and to all the sensors on the other hand.

According to another characteristic of the invention, the control and measurement unit sends a reset signal to the counter associated with the first recovery device each time the second recovery device switches over.

Advantageously, the two position sensors associated with each recovery device are in different logic states for each stable position of the recovery device, and the control and measurement unit regularly tests the logic states of the sensors in order to be able to detect an anomaly of operation in sensors. The control and measurement unit can thus remedy the malfunction of a sensor and itself count the number of switches of the recovery device associated with the defective sensor. Thus, the control and measurement unit can automatically make a correction in the number of switches recorded by the counter associated with the faulty sensor. In other words, the measurements can continue until the defective sensor is replaced. However, such continuity of operation could not be obtained with the use of a single sensor to detect the tilting of a recovery device.

According to another exemplary embodiment, the means for counting the tilting of the recovery devices do not include counters, and it is the control and measurement unit which directly manages the counting of the tilting by testing then almost permanently. the position sensor states. However, in this solution, the control and measurement unit must be available to carry out these tests, which is to the detriment of the other tasks which it must perform.

According to an important advantage of the invention, the combination of two recovery devices whose switching thresholds are different, allowing _to refine the accuracy of measurements of the amount of water fell during precipitation and the duration of - whatever the intensity of this precipitation.

According to another advantage of the invention, the rain gauge remains of a simple structure which allows it to have reliable operation, and is of low manufacturing cost.

Other advantages, characteristics and details of the invention will emerge from the explanatory description which follows, given with reference to the appended drawings which are given solely by way of example and in which:

FIG. 1 is a schematic axial section view of a rain gauge according to the invention, and

- Figure 2 is a schematic view in principle to illustrate the electrical means and electronics that control the operation of the rain gauge.

The rain gauge 1 illustrated in FIG. 1 comprises a fixed inlet funnel 3, of vertical axis X-χ for receiving and directing rainwater from atmospheric precipitation towards a first recovery device 5.

This first recovery device 5 comprises a double bucket 5a and 5b, mounted articulated around a horizontal axis Yl-Yl and capable of tilting between two stable positions. In one of these two positions, the trough 5a occupies a filling position while the trough 5b is in a emptying or evacuation position. Conversely, in the other of these two positions, the trough 5a occupies a emptying or evacuation position while the trough 5b is in a filling position.

The first recovery device 5 is mounted below the inlet funnel 3, so that that of the two buckets 5a or 5b which is in a filling position, is located substantially opposite the opening of outlet 7 of the inlet funnel 3 to be supplied with rainwater.

The tilting threshold of the first recovery device 5 is determined by the amount of rainwater recovered by that of the buckets 5a or 5b which is in a filling position. The two buckets 5a and 5b have the same shape and the same dimensions so that the tilting of the first recovery device 5 from one position to the other can be carried out from the same tipping threshold corresponding to an amount of rainwater recovered which is of the order of 2 cm ³ for example.

The rain gauge 1 also comprises a second device 10 for recovering rainwater which has a structure similar to that of the first device 5, namely that it comprises a double trough 10a and 10b, mounted articulated around a horizontal axis Y2 -Y2 and capable of switching between two stable positions for each of which one bucket is in a filling position while the other bucket is in a draining position.

The second recovery device 10 is mounted below the first device 5, so that that of the two buckets 10a or 10b which is in a filling position, can recover the rainwater which is poured out, after each tilting , by the bucket 5a or 5b which is in an emptying position.

In general, the tilting threshold of the second recovery device 10 corresponds to an amount of water recovered by one of the two buckets 10a or 10b, which is greater than the amount of water required for the tilting of the first device recovery 5. The tilting threshold of the second device 10 corresponds to an amount of rainwater recovered which is of the order of 20 cm ³ for example. Thus, the frequency of switching of the second recovery device 10 will be lower than that of the first device 5.

Advantageously, the second recovery device 10 is fed from a funnel intermediate 12 which is mounted between the two recovery devices 5 and 10. This intermediate funnel 12 is therefore dimensioned so as to be able to receive either the rainwater recovered in the trough 5a or 5b of the first recovery device 5. The outlet 13 of the intermediate funnel 12 is located substantially opposite and above the trough 10a or 10b of the second detection device 10 which is in a filling position. When the trough 10a or 10b of the second recovery device 10 is in a filling position, it can also be fed from the inlet funnel 3 when the level of rainwater reached in this funnel 3 exceeds a threshold determined. To this end, one end of a bypass duct 15 opens into the inlet funnel 3 at a height of the latter which corresponds to a determined quantity of water, while the other end of the bypass duct 15 opens opposite the intermediate funnel 12 to direct the rainwater to the second recovery device 10 without passing through the first device 5.

Referring to FIG. 2, the rain gauge 1 is equipped with electrical and electronic means 20 which are intended to measure the duration of a precipitation of water and the quantity of water fallen from the tilting of the two recovery devices 5 and 10.

By way of example, these means 20 comprise two position sensors associated with each recovery device 5 and 10 to detect their tilting between their two stable positions. More specifically, two sensors 22a and 22b are located in the vicinity of the two stable positions of the first recovery device 5. Each sensor 22a and 22b is in a logic state ^" 0 ^" or "i" and changes state with each switching of the first recovery device 5. Advantageously, the two sensors 22a and 22b are in different logic states for each stable position of the first recovery device 5. Thus, for example, for a stable position of the first recovery device 5 which corresponds at the trough 5a in a filling position and at the trough 5b in a draining position, the two sensors 22a and 22b are respectively in logic states ^" 0 ^" and "1", and vice versa for the other stable position of the first recovery device 5.

The two position sensors 24a and 24b associated with the second recovery device 10 operate on the same principle as that of the position sensors 22a and 22b.

The two position sensors 22a and 22b are electrically connected to a first counter _C1 , while the two position sensors 24a and 24b are electrically connected to a second counter C2. The two counters C1 and C2 are in turn electrically connected to a control and measurement unit 25 which has the particular function of resetting the first counter C _l after each switching of the second recovery device 10. The unit 25 receives also the signals emitted by all the sensors for reasons which will be explained below.

Referring again to FIG. 1 and according to a preferred embodiment of the rain gauge 1, the outlet orifice 7 of the inlet funnel 3, the tilting axis Yl-Yl of the first recovery device 5, the outlet orifice 13 of the intermediate funnel 12 and the tilting axis Y2-Y2 of the second recovery device 10, are axially aligned along the vertical axis XX defined by the inlet funnel 3.

The inlet funnel 3 and the intermediate funnel 12 are mounted on the same support 30, which also supports the tilting axes Yl-Yl and Y2-Y2 of the two recovery devices 5 and 10. This support

30 rests on a base 31 via feet

32 adjustable in height, and includes a spirit level 35 for example, so as to facilitate the aforementioned alignment along the vertical axis X-X. Finally, as is required in meteorological stations, the rain gauge 1 is surmounted by a large funnel 40 which actually collects rainwater and whose outlet orifice 42 is used to feed the inlet funnel 3 of the rain gauge 1. This large funnel 40 can have an inlet section which is

400, 1000 or 2000 cm depending on the standards in force, for example. The positioning of this large funnel 40 is not critical, it is simply necessary for its outlet orifice 42 to be located opposite the inlet funnel 3. The precision of the positioning of this funnel ₀ will essentially relate to its horizontality.

The large funnel 40 is removably mounted on a support 45 which can be independent of the support 30 of the rain gauge 1.

In operation, the water resulting from atmospheric precipitation, falls inside the large funnel 40 and flows through the outlet orifice 42 into the inlet funnel 3 of the rain gauge 1. The water s' then flows through the outlet orifice 7 of the inlet funnel 3 to gradually fill the trough 5a of the first recovery device 5 which is in a filling position. As soon as the quantity of water stored in the trough 5a corresponds to the tilting threshold of the first recovery device 5, the latter switches to its other stable position where the trough 5a is in a discharge position and the trough 5b in a filling position for recovering in turn the rainwater flowing through the outlet orifice 7 of the inlet funnel 3. As a result of the tilting of the first recovery device 5, the two sensors position 22a and 22b will change logic state, that is to say take respectively the logic states _" i _{" and} t "0 ^" , and the counter Cl associated with the two sensors 22a and 22b will be incremented by one unit . More precisely, if it is assumed that the counter C1 is sensitive to a rising edge, its incrementation will result from the transition from the logic state “0” to the state “1” of the sensor 22a.

The rainwater which is discharged through the trough 5a of the first recovery device 5 is discharged in the intermediate funnel 12 and flows through the outlet orifice 13 of this funnel 12 to gradually fill the trough 10a of the second recovery device 10 which is in a filling position. As soon as the quantity of water stored by the bucket 10a corresponds to the tilting threshold of the second recovery device 10, the latter switches to its other position. Following the tilting of the second recovery device 10, the two position sensors 24a and 24b will change logic state, that is to say take respectively the logic states "1" and "0" for example, and the counter C2 associated with the two sensors 24a and 24b will be incremented by one unit as a result of the detection of the rising edge of the sensor which goes from logic state "0" to logic state "1". Following the increment of the counter C2, the control and measurement unit 25 sends a reset reset signal to the counter C1.

The detection of tilting of the two recovery devices 5 and 10 by means of the detection sensors 22a, 22b, 24a and 24b, offers an additional advantage compared to systems which would use only one sensor for each recovery device. According to the invention, the control and measurement unit 25 can regularly test the state of the sensors, knowing that the two sensors 22a and 22b on the one hand and the two sensors 24a and 24b on the other hand, must be in different logical states outside the actual switching phase. In these conditions if the sensors 22a and 22b or the sensors 2 ^4a and 24b are in the same logic state after the tilting of the associated recovery device, the control and measuring unit 25 will detect a tilting while this tilting will not counted by the Cl or C2 counter. Thus, the control and measurement unit 25 will automatically make the necessary correction, at a ready changeover, to the number of changeovers counted by the counters C1 and C2. In other words, in the event of failure of a sensor 22a or 22b and / or of a sensor 24a or 24b, the control and measurement unit 25 can itself count the tiltings because it is able to detect a tilting regardless of meters. In addition, by knowing the logical states of the sensors, it can determine which of the sensors is broken.

Under these conditions, according to another exemplary embodiment of the tilt counting means, the counters C1 and C2 are deleted. In this case, the control and measurement unit 25 ensures the counting itself, but this is done to the detriment of the other tasks that it can perform.

Generally, in the case of light rain which causes the second recovery device 10 to tip over, the number of toppings of the first recovery device 5 will make it possible to provide better measurement accuracy.

In the event of heavy rain, the second recovery device 10 will also be powered by the bypass duct 15 as soon as the quantity of rainwater received by the inlet funnel 3 reaches a determined level. Without this provision, the accuracy of the measurement would be impaired. The advantage of the first recovery device 5 then lies in the fact that it gives more temporal information on the start of precipitation than quantitative information.

This time information given by the first recovery device 5 also occurs in the presence of dew or a fine rain which will result in a fairly low switching frequency of the first recovery device 5.

Finally, in the case of intermittent rain, the second recovery device 10 may contain in its bucket 10a or 10b an amount of rainwater insufficient to trigger its tilting, which can be the source of an imprecision on the measured. In this case, the presence of the first recovery device 5 makes it possible to attenuate this imprecision because its tilting threshold is lower.

In the example described above, there is a factor 10 between the switching thresholds of the two recovery devices 5 and 10. Of course, this factor is not limited to this value.

Claims

1. Gauge comprising a first dispo _¬ recovery operative part (5) double trough (5, _5a) _of an atmospheric water precipitation, pivotably mounted between two stable positions for discharging, at each changeover, a determined quantity of water of rain which is recovered between two successive tiltings, and a second recovery device (10) with double bucket ⁽ 10, 10a ⁾ , mounted tilting and intended to recover at least the quantity of water discharged after each tilting of the first recovery device (5), the tilting threshold of this second recovery device ₍ 10 ₎ corresponding to a quantity of water which is greater than that necessary for the tilting of the first recovery device ⁽ 5 ⁾ , characterized in that it comprises means counting (20) of the tilting of the two devices ⁽ 5,10 ⁾ and a control and measurement unit ⁽ 25 ⁾ connected to the counting means (20), to determine the duration and the qu amount of rain water fell during precipitation.

2. Rain gauge according to claim _1, characterized in that it comprises a _funnel fixed inlet ^⁽³⁾ for receiving and directing rain water toward the first recovery device (5), and in that the second device recovery (10) is also directly fed from this inlet funnel ⁽ 3 ⁾ when the level of rain reached in the latter exceeds a determined threshold.

3. Rain gauge according to claim 2 _, characterized in that the rainwater discharged after each tilting of the first recovery device ₍ 5 ₎ is poured into a fixed intermediate funnel ₍ 12 ₎ which feeds the second recovery device (10 ₎ .

4. Rain gauge according to claim 3, characterized in that the inlet funnel (3) and the intermediate funnel (12) communicate with each other by a bypass duct (15).

5. Rain gauge according to any one of the preceding claims, characterized in that the counting means (20) of the tiltings of each recovery device (5; 10) comprise two position sensors (22a, 22b; 24a, 24b) for detect the two stable positions of each recovery device (5; 10).

6. Rain gauge according to claim 5, characterized in that the counting means (20) also comprise two counters (C1; C2) connected to the two position sensors (22a, 22b; 24a, 24b) of the two recovery devices (5 ; 10) on the one hand, and _the unit of control and measurement (25) on the other.

7. Rain gauge according to claim 6, characterized in that the control and measurement unit (25) sends a reset signal to the counter (Cl) of the first recovery device (5) each time the second device switches over. recovery (10).

8. Rain gauge according to claim 6 or 7, characterized in that the position sensors (22a, 22b;

24a, 24b) associated with each recovery device ₍ 5 _; 10) are in different logical states for each stable position of the associated recovery device.

9. Rain gauge according to claim 8, characterized in that the position sensors (22a, 22b;

24a, 24b) associated with each recovery device

₍ 5 _; 10) are also connected to the control and measurement unit (25), said unit (25) controlling the number of effective tilting of the two recovery devices ⁽ 5; 10) in the event of a sensor failure.