EP1902433A1

EP1902433A1 - Device for detecting a body falling in a pool

Info

Publication number: EP1902433A1
Application number: EP05786098A
Authority: EP
Inventors: Anthony Ginter
Original assignee: MG International SA
Current assignee: MG International SA
Priority date: 2005-07-01
Filing date: 2005-07-01
Publication date: 2008-03-26
Also published as: WO2007003719A1; US20100079293A1

Abstract

The invention concerns a device for detecting a body falling in a volume of water (20) of a pool comprising a probe (1) adapted to transmit aquatic waves propagated in the pool (20) and an electronic unit (4) adapted to receive and interpret electric signals representing pressure variations caused by the aquatic waves received by the probe. The probe (1) has a free end (11) immersed in the pool (20) and a substantially vertical axis (12). The device further comprises an immersed rigid obstacle (3) extending between the immersed end of the probe and the surface of the volume of water of the pool in a plane substantially perpendicular to the axis of the immersed probe. The rigid obstacle (3) enables disturbances caused by the surface waves to be eliminated from the measurements of pressure variations caused by the aquatic waves in the probe (1).

Description

DEVICE FOR DETECTING THE FALL OF A BODY IN A BASIN

The present invention relates to a device for detecting the fall of a body in a pool such as a swimming pool, in particular the fall of a child or an animal. Such a device makes it possible to detect the fall of a body in a body of water and alert the entourage, by a siren, lights, or any other means adapted to attract attention, to allow a quick rescue.

Indeed, the drowning of young children concerns many domestic accidents.

There are many safety devices such as protective barriers surrounding the pool with an access gate. However, it is necessary to properly close the door at each passage. In addition, children of about three years of age can manage to open such a gate while they are still very exposed to drowning.

There are also safety devices such as shelters, blankets or shutters covering the pool. Such a device is however unsightly and requires a complex operation to be removed before use of the pool.

The ideal solution to effectively prevent falls in the pool while maintaining easy access and a friendly seal is to provide the pool with a body falls detection device in the pool.

Such detection devices exist and are marketed. For example, Aquapremium ™ devices, Aquasensor ™ SensorPremium, SensorSolar, SensorElite, SensorEspio or SensorDomo marketed by the applicant can detect the fall of a body in the pool of a pool and alert the entourage.

Known fall detection devices generally consist of a probe plunging into the basin and connected to an emerging housing. Figure 1 depicts a known detection device.

Figure 1 shows a detection device disposed on the lip 30 of a basin 20, such as a pool for domestic use for example. A probe 1 dips into the pool water and opens into a compression chamber 8 formed in a portion of the housing 7 of the detection apparatus. The compression chamber could be directly constituted by the immersed probe itself filled with air and serving as compression chamber. The probe 1 is generally a tube at least partially filled with air having a free end immersed and an end opening into the housing 7 of the apparatus of detection emerged. The tube 1 is thus adapted to transmit water waves that propagate in the basin 20 to the compression chamber 8. This chamber is hermetically sealed and perceives the rising water waves of the tube 1 as pressure variations. A pressure sensor 2, for example of the piezoelectric type, is arranged in the compression chamber 8 to convert the pressure variations into electrical signals. The pressure sensor 2 is connected to an electronic unit 4 disposed in the housing 7 of the detection apparatus, outside the compression chamber 8.

Any movement in the basin 20, and in particular the fall of a body, causes the formation of waves that induce pressure variations in the compression chamber 8 of the fall detector. The sensor 2 converts these pressure variations into voltage and the electronic card 4 processes these signals to interpret whether they correspond to a fall. If necessary, the electronic card 4 controls the emission of an alert signal by releasing a siren 6 and / or by transmitting a signal to a remote control center via an antenna 5 or any other appropriate telecommunication link. However, the known detection devices have the disadvantage of being sensitive to external disturbances and of being subjected to nuisance tripping, because the electronic card interprets disturbing signals such as a fall. Such disturbing signals may be due to the movement of the robot cleaner, the start of filtration, but also to rain or waves caused by wind. These disturbances can cause a nuisance tripping of the alarm, which becomes annoying for the entourage and can encourage to put the device at a standstill with the risk of not detecting a real fall. Most of these disturbances can be eliminated by adjusting the sensitivity of the detector.

On the other hand, surface waves, in particular due to the wind, strongly disturb the detection of the submarine waves because they modify the level of the water around the probe. Indeed, the immersed probe transmits the pressure variations due to the submarine waves by transmitting the thrust of the water of the basin rising in the tube on the air filling said tube. This measurement is explained by well-known physical phenomena and in particular by the principle of Archimedes which states that every body immersed in a fluid receives a thrust from below upwards equal to the weight of the volume of the fluid displaced, and by Boyle-Mariotte's law which states that at constant temperature, the volume of a gas is inversely proportional to the pressure it receives.

Thus, when the water level is changed near the probe, the pressure in the probe is changed and the measurement of the amplitude of the submarine waves is parasitized. This parasitic signal, derived from the measurement of the surface waves around the probe, adds to the signal, said to be useful, generated by the basin during a fall. Depending on the parasitic and useful signal phase shift, the sensor can read a wave amplitude underwater more or less strong than it actually is. If the amplitude of the spurious signal is subtracted from the amplitude of the submarine wave, an actual fall detection may be delayed and if the amplitude of the spurious signal adds to the amplitude of a submarine wave, a nuisance tripping of the alarm can be caused.

Adjusting the sensitivity of the detector can not mitigate this phenomenon without risking a real non-detection of fall.

There is therefore a need to reduce the risk of nuisance tripping of the alarm of the detection device due to the surface effects on the pool of the pool while ensuring a real fall detection in the water basin.

For this purpose, the invention proposes to protect the probe from the effects of surface waves by creating a rigid obstacle between the immersed free end of the probe and the surface of the water. Thus, the pressure variations generated by the surface waves are not transmitted inside the tube of the probe and the pressure detector only detects the pressure variations due to the water waves propagating under the rigid obstacle.

The invention more particularly relates to a device for detecting a fall of a body in a water body of a basin comprising: a probe adapted to transmit aquatic waves propagating in the basin, the probe having a free end immersed in the basin and a substantially vertical axis; an electronic unit adapted to receive and interpret electrical signals representative of pressure variations caused by the water waves collected by the probe; a rigid immersed obstacle extending between the immersed end of the probe and the surface of the water body of the pool in a plane forming an angle with the axis of the immersed probe.

According to one embodiment, the rigid obstacle is a plate comprising an opening through which the probe passes.

According to the embodiments, the device according to the invention further comprises one or more of the following characteristics: the plate extends in a plane forming an angle between 10 ° and 170 ° with the axis of the probe; the plate is integral with the probe; the plate is fixed to the basin; the plate has a thickness of between 1 and 5 mm.

According to one embodiment, the rigid obstacle is formed by a bent portion of the probe. According to one characteristic, the probe has a first part extending in the axis of the probe and a second portion having at least one portion forming an angle with said axis, the second part being totally immersed.

According to another characteristic, the bent portion of the probe makes an angle between 40 ° and 90 ° with the axis of the probe. According to the embodiments, the detection device according to the invention further comprises one or more of the following characteristics: the rigid obstacle has an area of between 10 and 350 cm; the probe is a tube at least partially filled with round, oval or trapezoidal base air; the device comprises a compression chamber comprising a pressure sensor connected to the electronic unit; the compression chamber is constituted by the hermetically sealed probe at its end opposite the immersed free end; the compression chamber is located in a housing of the device, the probe opening into said compression chamber at its end opposite the immersed free end. The features and advantages of the present invention will become apparent from the following description given by way of illustrative and nonlimiting example, and with reference to the figures which represent: FIG. 1, already described, a diagram of a detection device known fall; - Figure 2, a diagram of a fall detection device a first embodiment of the invention; FIGS. 3a to 3d are diagrammatic examples of surface wave detection obstacles that can be used on the device of FIG. 2;

- Figure 4, a diagram of a fall detection device a second embodiment of the invention;

FIGS. 5a and 5b are diagrammatic examples of surface wave detection obstacles that can be used on the device of FIG. 4.

In the context of the invention, the term "water waves" any movement of water mass in the basin either on the surface (waves) or in depth (submarine waves), and the expression "signals generated by the basin "to designate electrical signals representative of the aquatic waves (waves and submarine movements) propagating in the basin and received by the electronic card of the device for detecting a fall via the immersed probe. FIG. 2 describes a detection device according to a first embodiment of the invention.

Figure 2 shows a detection device disposed on the lip 30 of a basin 20, such as a pool for domestic use for example. A probe 1 dips into the pool water and opens into a housing 7 of the detection apparatus. The probe 1 is a tube at least partially filled with air having a first free end 11 immersed approximately 5 to 30 cm below the water level and a second end connected to the housing 7 of the device. The probe also has a substantially vertical axis 12. Indeed, as explained above, the probe 1 must transmit the pressure variations induced by the water waves to a pressure sensor 2, these pressure variations being due to the thrust of the water on the air trapped in the tube according to the principle of Archimedes recalled above. It is therefore preferable that at least a portion of the tube of the probe 1 is vertical so that the pressure variations can be detected with a sufficient amplitude according to this principle.

In FIG. 2, the compression chamber is directly constituted by the immersed probe 1 at least partially filled with air. The end of the tube 1 opposite the submerged end is hermetically sealed and a pressure sensor 2 is directly placed at this end, for example in a gland which allows the tight closure of the tube 1 while allowing the passage of a electrical connection. The pressure sensor 2 thus perceives the aquatic waves rising in the tube 1 as pressure variations and transforms these pressure variations into electrical signals. The sensor 2 may be of the piezoelectric type and be connected to an electronic unit (not shown) disposed in the housing 7 of the detection apparatus.

The electronic unit is adapted to receive and interpret the signals coming from the pressure sensor 2, that is to say the electrical signals representative of the pressure variations in the probe 1 serving as a compression chamber, thus representative of the aquatic waves. propagating in the basin.

The electronic unit is adapted to interpret the signals generated by the pool in that it can correlate, for example, amplitude and frequency values of electrical signal with a fall detection. The electronic unit may include a microcontroller chip, in a manner known per se. In general, the electronic unit is adapted to interpret an electrical signal received from the pressure sensor 2 as corresponding to a fall when said electrical signal is a sinusoid having an amplitude greater than a predetermined threshold with a frequency close to 1 Hz. Such a signal is indeed characteristic of a fall of a body in water. The electronic unit is then adapted to control the triggering of an audible alarm disposed in the housing for example. The electronic unit can also trigger the transmission of an alert signal by a radio transmitter to a remote siren, for example in the house.

However, as indicated above, the surface waves can interfere with the measurement of the amplitude of the submarine waves and cause either a delay of a fall detection or a nuisance triggering of the alarm. Indeed, the aquatic waves are perceived by the electronic unit of the detection device as a sinusoidal electrical signal. This sinusoidal signal is classically quantized in half-wave, a half-wave corresponding to a half-period of the sinusoidal signal whose peak exceeds a predetermined threshold of amplitude. Thus, when the electronic unit receives an electrical signal from the pressure sensor whose amplitude exceeds said predetermined threshold, it counts this event as valid information. If it detects a certain amount of successive and non-missing valid information in a predefined frequency range around 1 Hz, it interprets this as a fall.

If surface waves disturb the measurement of the water waves, the pressure sensor 2 may transmit a different pressure value than that generated by the single water wave and the electronic unit may then miss valid half-wave information and delay fall detection; or count invalid valid half-wave information and trigger the alarm unnecessarily.

The invention therefore proposes introducing a rigid obstacle 3 between the immersed end 11 of the probe 1 and the surface of the water. This rigid obstacle 3 forms an angle with the axis 12 of the probe 1. For optimum efficiency, the rigid obstacle 3 may extend in a plane substantially perpendicular to said axis 12, that is to say substantially at least 'horizontal. The rigid obstacle 3 may, however, be oriented in a plane other than the horizontal plane, for example in a plane forming an angle of between 10 ° and 170 ° with the axis 12 of the probe 1. The submerged free end 11 of the probe 1 is thus protected from the pressure variations coming from the surface waves and transmits into the tube of the probe 1 only the pressure variations originating from the aquatic waves propagating under the obstacle 3.

The obstacle 3 must be rigid enough to reflect the water waves coming from the surface without transmitting pressure variation to the water body below. The shape and size of the obstacle 3 are chosen to protect the submerged free end 11 of the tube.

In the embodiment illustrated in Figure 2, the rigid obstacle is constituted by a plate 3 positioned around the probe 1 and extending in a plane perpendicular to the axis 12 of the probe. The plate 3 is therefore substantially parallel to the surface of the water and can return upward the pressure variations due to the surface waves, without transmitting pressure variation downwards towards the free end 11 of the probe 1. The plate 3 can be fixed directly to the tube of the probe 1 and / or hooked to the wall of the basin 20 and / or to the housing 7 of the device.

Figures 3a to 3d illustrate different forms of possible plates to constitute the rigid obstacle. It is understood that other forms may be considered different from the four illustrated forms.

The plate 3 can be made of plastic, for example FABS (Acrylonitrile Butadiene Styrene) or polycarbonate, and can be obtained for example by injection molding in a manner known per se. The plate 3 has an opening 31 for positioning the plate 3 around the tube of the probe 1 as illustrated in FIG. 2. The opening 31 is preferably chosen with a periphery corresponding to the shape of the probe 1, this is that is, the plate 3 will have a round opening 31 if the probe is cylindrical with a circular base or an oval or trapezoidal opening if the probe is cylindrical with an oval or trapezoidal base. Any other form of opening 31 may be envisaged, depending on the forms of probe used for the detecting devices. In addition, the dimensions of the opening 31 are preferably chosen to fit around the periphery of the probe so as not to allow water to pass through the opening 31 when the plate 3 is placed around the probe. The plate 3 can thus be clipped onto the tube of the probe 1, for example in a groove provided for this purpose; the plate can also be glued to the tube of the probe and permanently secured to the tube. The plate 3 can also be placed around the tube of the probe 1 and fixed elsewhere, for example with a rod connecting the plate to a fastening system, for example a suction cup, on the wall of the basin or under the housing of the device.

The plate 3 is sufficiently rigid and extended to act as an obstacle to pressure variations due to surface waves. The plate may have a thickness of between 1 and 5 mm and extend over a surface having an area of between 10 and 350 cm ² . The shape of the plate - round, square, oval, arcuate, etc .... - depends on the shape and size of the detection device on which it is placed, and the distance between the probe and the basin wall.

Figure 3d shows a plate having a top surface, i.e. facing the surface of the water, with flutes. Such a surface makes it possible to attenuate the aquatic waves propagating from the surface rather than to send them towards the top of the basin. FIG. 4 describes a detection device according to a second embodiment of the invention. The elements identical to Figure 2 bear the same reference numbers.

In the embodiment illustrated in FIG. 4, the rigid obstacle is constituted by a bent portion of the tube of the immersed probe 1. The tube is generally made of rigid plastic and can therefore serve to constitute the obstacle without requiring the use of an additional room.

The probe 1 always has a substantially vertical axis 12 as described above and for the same reasons of efficiency of measurement of the amplitude of the aquatic waves by pressure variation. The submerged free end 11 of the probe 1, however, is not situated in the continuity of this vertical axis 12. The probe 1 has a portion forming an angle with the vertical axis of thrust of the water on the trapped air in the tube. The upper wall 3 of this tube portion forms a rigid obstacle between the surface of the water and the free end 11 of the tube. According to the models of probes used, the upper wall of the bent portion of the tube may form an angle between 40 ° and 90 ° with the axis 12 of the probe 1.

Figures 5a and 5d give two examples of obstacles 3 constituted by the probe 1 itself. It is understood that other forms can be envisaged.

The probe 1 has a first portion 13 intended to extend along a substantially vertical axis 12 when the probe is immersed in the basin (FIG. 4). This first part 13 is intended to transmit the pressure variations caused by the water waves to the sensor 2, according to the physical principles mentioned above. The probe 1 also has a second portion 14 which has a connecting bend and at least a portion 3 forming an angle with the aforementioned vertical axis. Preferably, the rigid portion 3 is substantially perpendicular to the vertical axis 12, but the tube portion forming the obstacle 3 may form an angle of between 40 ° and 90 ° with the axis of the probe. The second portion 14 is intended to be totally immersed when the probe is immersed in the basin (Figure 4). The upper surface of the bent portion 3 of the probe then constitutes an obstacle to the transmission of the pressure variations due to the surface waves towards the immersed free end 11 of the probe 1. Although not illustrated, the bent portion of the probe may have a hook or S shape with several junction elbows. Whatever the form envisaged, it is necessary that the probe 1 has a substantially vertical portion for the transmission of pressure variations to the sensor 2 and a totally immersed portion having an angle with the vertical, preferably a right angle. The submerged free end 11 of the probe may be located at one end of the bent portion, as shown in FIG. 4, or at one end of another vertical portion of the probe, the bent portion being located in a central zone. of the probe.

The bent portion 3 is indeed a rigid obstacle within the meaning of the invention, with a surface substantially perpendicular to the axis 12 of the probe located between the surface of the water and the submerged end 11 of the probe. This bent portion 3 is preferably sufficiently long to allow a good stop of the propagation of surface water waves propagating towards the free end 11 of the probe, for example a bent portion length of between 5 cm and 20 cm is adapted to different form of probe to form a rigid obstacle having an area of between 10 and 350 cm ² .

The fall detection device according to the invention thus makes it possible to measure the pressure variations induced by the aquatic waves propagating in the basin without parasitizing these measurements with pressure variations induced by a variation in the level of the water due to the waves. of surface. The detection of a body drop in the pool is thus optimized and nuisance tripping of the alarm is limited.

Of course, the present invention is not limited to the embodiments described by way of example. In particular, the probe 1 may not be hermetically closed at its upper end and open into a compression chamber located in the housing of the detection device. On the other hand, other forms of obstacles 3 may be envisaged, in particular an S-shaped or hook-shaped shape of the probe 1 rather than the illustrated L shape.

Claims

1. Device for detecting a fall of a body in a water body (20) of a basin comprising: - a probe (1) adapted to transmit aquatic waves propagating in the basin (20), the probe having a submerged free end (11) in the basin and a substantially vertical axis (12);

- an electronic unit (4) adapted to receive and interpret electrical signals representative of pressure variations caused by the water waves collected by the probe (1);

a rigid immersed obstacle (3) extending between the immersed end of the probe and the surface of the pool of water mass in a plane forming an angle with the axis of the immersed probe.

2. Detection device according to claim 1, characterized in that the rigid obstacle (3) is a plate comprising an opening (31) through which the probe (1).

3. Detection device according to claim 2, characterized in that the plate (3) extends in a plane forming an angle between 10 ° and 170 ° with the axis (12) of the probe (1).

4. Detection device according to claim 2 or 3, characterized in that the plate (3) is integral with the probe.

5. Detection device according to one of claims 2 to 4, characterized in that the plate (3) is fixed to the basin.

6. Detection device according to one of claims 2 to 5, characterized in that the plate (3) has a thickness of between 1 and 5 mm.

7. Detection device according to claim I ₅ characterized in that the rigid obstacle (3) is formed by a bent portion of the probe (1).

8. Detection device according to claim 7, characterized in that the probe (1) has a first portion (13) extending in the axis (12) of the probe and a second portion (14) having at least one portion (3) forming an angle with said axis, the second portion (14) being fully immersed.

9. Detection device according to claim 8, characterized in that the bent portion (3) of the probe is at an angle between 40 ° and 90 ° with the axis (12) of the probe (1).

10. Detection device according to one of claims 1 to 9, characterized in that the rigid obstacle (3) has an area of between 10 and 350 cm ² .

11. Detection device according to one of claims 1 to 10, characterized in that the probe (1) is a tube at least partially filled with round, oval or trapezoidal base air.

12. Detection device according to one of claims 1 to 11, characterized in that it comprises a compression chamber (8) comprising a pressure sensor (2) connected to the electronic unit.

13. Detection device according to claim 12, characterized in that the compression chamber is constituted by the probe (1) hermetically closed at its end opposite the immersed free end (11).

14. Detection device according to claim 12, characterized in that the compression chamber is located in a housing of the device, the probe (1) opening into said compression chamber at its end opposite the immersed free end (11). .