FR2468069A1 - Fluid leakage detector for intermittently used supplies - uses metal ball in flow and proximity detector circuit to initiate timing of flow duration against preset max. time - Google Patents

Abstract

Flow detection is on a yes-no basis rather than proportional to flow rate and the time duration of the flow is measured against a pre-set max. time to activate an alarm and/or automatic turn off of the water supply if the preset time is exceeded. The flow detector comprises a metal ball (7) placed in the fluid path so it is readily lifted off its no-flow seat (8) to a grille (9) limiting the upward travel. An electronic metal detector circuit (10) senses the rising of the metal ball through the wall (5a) of the flow chamber. The signal from the detector is fed (11) to a circuit which triggers an astable multivibrator (2) whose output pulses are counted in a pre-set counter circuit (2) which gives a signal when the pre-set count is reached. This signal may operate an alarm or switch a motor (13) driven ON-OFF valve (18).

Description

 The present invention relates to an apparatus for detecting the existence of a leak in a circuit traversed discontinuously by a fluid.

 The present invention is particularly applicable to water distribution circuits and, in particular, to a domestic water supply installation. In the following description, the invention will be described in connection with such an installation, but it goes without saying that it is applicable in all cases where a circuit is traversed discontinuously by a liquid or gaseous fluid.

The present invention is based on the following finding. In water supply installations of the type indicated above, water-using appliances connected to the supply installation, for example sanitary appliances and / or household appliances such as washing machines or dishwasher, operate discontinuously from the point of view of the water supply rate. This is how, with each operation, each device is supplied with water for an interval of time which can range from a few tens of seconds to a few tens of minutes. In addition, all the devices connected to the installation generally do not work one after the other with overlapping of their operating time, so that the overall flow rate of the water supply installation itself is discontinuous. The maximum duration of the flow corresponding to an operation or a group of successive operations and overlapping in time can be statistically determined and does not usually exceed one, half an hour or at most 1 hour.

 Consequently, if the water supply system delivers water for a period whose value exceeds a predetermined maximum value, this will be a sign of the existence of a leak.

 The present invention therefore aims to provide an apparatus based on the observation indicated above and making it possible to detect the existence of leaks.

 To this end, the apparatus according to the invention is characterized in that it comprises a flow detector device capable of producing a signal when it detects a flow, a timer device which produces a control signal in response to the signal delivered. by the flow detector device when the duration of this last signal exceeds a predetermined value, and which is reset to zero when said duration remains less than said predetermined value, and a device controlled by the control signal produced by the timer device and to stop the leak.

By controlled device for stopping the leak is meant a device acting indirectly or directly to stop the leak. According to an embodiment of the present invention, the controlled device can comprise an alarm device which, when the device detects the existence of a leak, emits an audible and / or light alarm signal which warns the user of the existence of a leak.

The latter can then close a stopcock to cut off the water supply and, consequently, stop the leak. According to another embodiment of the present invention, the controlled device can comprise an electrically controlled shut-off valve, which is inserted in the water supply installation and which is closed automatically in response to the control signal delivered. by the timer device. Of course, the controlled device can include both an alarm device and an electrically controlled shut-off valve. In all cases, the leak will be stopped and the user will have plenty of time to locate and remedy it.

The flow detector device can be realized in many ways. It will be noted that, in the present invention, it is not a question of quantitatively measuring a flow rate, but simply of detecting the presence or absence of a flow and, then, of measuring the duration during which the flow is present . The flow detector device can therefore be constituted by a very simple device operating all or nothing and using for example a proximity detector of any type known, electro-mechanical, electro-optical or electro-magnetic.

A detailed description will now be given of an exemplary embodiment of the present invention with reference to the appended drawings in which
Figure 1 shows a block diagram of the apparatus according to the present invention.

 Figure 2 is a view partly in section and partly in elevation showing a practical embodiment of the apparatus according to the invention.

 As shown in FIG. 1, the apparatus according to the invention essentially comprises a flow detector 1 which controls, when it detects a flow, the activation of a timer or timer 2 which in turn controls the entry into action of an alarm device 3 and / or of an electrically controlled stop valve 4 when the duration of the flow detected by the detector 1 exceeds a predetermined value, and which is reset to zero when said duration remains less than said predetermined value.

In the practical embodiment shown in FIG. 2, the device according to the invention comprises a pipe 5 provided at each of its ends with a connection member 6 allowing it to be mounted in series in a water circuit to against, for example immediately at the outlet of the water meter of a domestic water supply installation or upstream of an appliance or group of appliances which use water discontinuously or another fluid and for which it is desired to be able to detect the existence of a leak.

 The pipe 5 has a part 5a of enlarged diameter.

The flow detector 1 comprises a movable member, for example a ball 7, which is movable in the pipe 5 between a first position (shown in phantom) located upstream of the part 5a in the absence of flow and a second position (shown in solid lines) located in said part 5a in the presence of a flow of water whose direction is indicated by the arrows. The two positions of the ball 7 are for example defined respectively by an annular seat 8 and by a gri 9. The flow detector 1 further comprises a proximity detector 10 placed near the second position of the ball 7. As proximity detector 10, a metal detecting probe can be used, for example. Probes of this gen are well known and it is not considered useful to describe them in detail. It will simply be noted that these probes deliver an electrical signal when they detect the presence of a metal in the vicinity of them. In this case, at least the part 5a of the pipe 5 and the grid 9 must be made of a non-metallic material, and the ball 7 must be metallic.

As shown in FIG. 2, the pipe 5 is preferably bent in the shape of a U and it is arranged vertically so that the U is inverted, the part 5a of enlarged diameter being formed in the first branch of the pipe 5 considering the direction of water flow. Thus, in the absence of water flow, the ball 7 which has a density greater than that of water will come automatically, by gravity, to be placed on the seat 8. The latter must be sufficiently distant from the probe 10 so that, in this position of the ball 7, it is not detected by the probe 10 and that the latter does not produce a signal. On the other hand, in the presence of a flow of water, the ball 7 is entrained by the water and abuts against the grid 9 where it is detected by the probe 10 which produces a signal on its output.

The output of the probe 10 is connected by an electrical connection 11 to the timer or timer 2. The timer 2 can be of any known type, for example electromechanical or entirely electronic. By way of example, the timer 2 can include an astable oscillator or multi-vibrator with fixed frequency, the starting of which is controlled by the output signal of the probe 10, and by a counter which counts the pulses at fixed frequency. delivered by the astable multivibrator and which delivers a signal on its own output when its content has reached an adjustable predetermined count corresponding to a predetermined duration of operation of the astable multivibrator, therefore to a predetermined duration of water flow detected by the probe 10 The counter is automatically reset when the astable multivibrator stops working. This can be obtained for example by cutting the current supply to the astable multivibrator and the counter in response to the stopping of the signal delivered by the probe 10 or by means of a reset circuit operating in response to the stopping. of the signal supplied by said probe. Such a timer can be produced in an extremely compact form using integrated circuits, so that the probe 10 and the timer 2 can be easily housed between the two branches of the U-shaped pipe 5.

 The timer 2 and the probe 10 are connected by a power cable 12 to a current supply source. If the device according to the invention is placed outside a house, the current source is preferably constituted by a battery or an accumulator. If the device according to the invention is placed inside a house or a room, the current source can be the sector. In the latter case, the direct current necessary to supply the timer 2 and the probe 10 can be obtained by means of a small transformer and a rectifier incorporated or not in the device according to the invention. On the other hand, if the proximity detector 10, the timer 2 and the motor 13 which will be described later are of a type capable of operating on alternating current, the current source will be the sector.

 The time after which the timer 2 produces its control signal is preferably adjustable so that it can be adapted to each use. For example, in the case where the apparatus according to the invention is mounted in a domestic water supply installation, this time is adjusted to a value greater than the maximum duration of water flow corresponding to an operation or to a group of operations likely to occur successively with overlap in time. In practice and in the application envisaged above, it will suffice to set this time to a value between 1/2 hour and 1 hour. In the example described above, if the repetition period of the pulses delivered by the astable multivibrator is for example 1 second, it will suffice to set the predetermined count of the counter to a number of pulses corresponding to the chosen duration.

 The timer 2 controls, on the one hand, by a conductor 14, an alarm device (not shown in FIG. 2) which can be constituted by an audible and / or light alarm, and, on the other hand, by a conductor 15, the electric motor 13. The latter, when it is started by the timer 2, drives via a speed reducer 16 the operating axis 17 of a stop valve 18 placed in series in the second branch of the pipe 5 in order to cut the water circuit. When such a shut-off valve 18 is provided, it is desirable that the alarm signal is maintained or at least that the alarm device includes a warning lamp which remains visible even when the shut-off valve has been actuated by timer 2 to cut off the water circuit, so that the user is certain that the device has detected the existence of a leak.

 As shown schematically by the rectangle in phantom 19, the entire apparatus, with the exception of the two ends 6 of the pipe 5 and possibly its elbow 20, can advantageously be placed in a sealed housing or embedded in a block of resin to protect its elements against humidity when the device is placed outside a home. When the device is embedded in a block of resin, arrangements are of course taken to allow the free rotation of the axis 17 of the stop valve 18. In addition, the outer end of the axis 17 projects the outside of the case or of the resin block 19 and is provided with a means such as for example a square 17a allowing manual opening of the stop valve 18 after the leak has been detected and repaired.

 The apparatus described above operates in the following manner. When a flow of water, even of small value, circulates in the pipe 5, the ball 7 comes into the position shown in solid lines in FIG. 2. It is then detected by the probe 10 which starts the timer 2 .

If the duration of the flow does not exceed the value preset on the timer 2, the latter is reset to zero and the ball 7 returns to its position shown in dashed line as soon as the flow of water stops, the apparatus being then ready to operate when a new water flow occurs.

On the other hand, if the duration of the water flow exceeds the value preset on timer 2, thus indicating the probable existence of a leak, timer 2 controls the activation of the alarm device and the closing of the electrically controlled shut-off valve 18 which will remain closed until it is opened manually by the user after the latter has located and repaired the leak.

 It is understood that the embodiment of the present invention which has been described above has been given by way of purely indicative and in no way limitative example, and that numerous modifications can be made by those skilled in the art. art without departing from the scope of the present invention. Thus, in particular that, if the device shown in FIG. 2 is not used in the vertical position, the ball 7 or any other movable member used in place of this ball can be recalled to the position shown in phantom by a non-metallic spring if the proximity detector 10 consists of a metal detecting probe.

In addition, if the location allows, the pipe 5, U-shaped can be arranged in an upright position, that is to say not overturned. In the latter case, the part Sa of enlarged diameter can be formed in the second branch or rising branch of the U, the annular seat 8 is always placed below the part 5a, and the stop valve 18 can be placed in series in the first branch of the U.

Furthermore, instead of the metal detecting probe 10, an electro-optical detector can be used as a proximity detector, for example, if the part 5a of the pipe 5 is made of a transparent material. If the part 5a of the pipe 5 is made of a non-magnetic material, for example copper, it is also possible to use a detector of the magnetic type by replacing the ball 7 by a permanent magnet capable of actuating a microswitch under a glass bulb placed in the place of probe 10.

Whereas in the embodiments of the flow detector 1 which have been described above, this detector comprises a movable element occupying one or the other of two positions depending on whether the fluid circulates in the pipe 5 , it is also possible to use a purely static detector, such as for example an electromagnetic detector if the fluid circulating in the pipe 5 is electrically conductive.

 It will also be noted that the apparatus according to the present invention can be combined with a fluid meter, for example a water meter. Indeed, all the fluid counters, whether purely mechanical, electro-mechanical, electro-optical or electro-magnetic, always include an element which has two states (rotation or not rotation, signal of a first value or d '' a second value, signal by pulse or continuous) depending on whether there is flow or not fluid flow. The flow detector 1 of the apparatus according to the present invention can therefore be combined with such a fluid meter by using said two-state element of this meter to detect the presence or absence of a fluid flow. , for the implementation of the present invention, the counting function of the fluid counter with which the apparatus according to the present invention is combined is not used, since it is not a question of measuring the value of a flow, but to detect the presence or absence of a flow, to measure the duration of said flow and to produce an alarm signal and / or to stop said flow if the measured duration exceeds a predetermined value indicative of the existence of a leak.

Furthermore, the stop valve 18 controlled by the geared motor 13, 16 can be replaced by a normally open solenoid valve, the closing of which is controlled by the output signal of the timer 2.

Indeed, the alarm device 4 can be placed on the device itself or at a distance from it at a place where its audible and / or light alarm signal will be easily audible and / or visible by the user.

Claims (9)

 1.- Apparatus for detecting the existence of a leak in a circuit traversed discontinuously by a fluid, characterized in that it comprises a flow detector device 1 capable of producing a signal when it detects a flow, a timer device 2 which produces a control signal in response to the signal delivered by the flow detector device 1 when the duration of this latter signal exceeds a predetermined value, and which is reset to zero when said duration remains less than said predetermined value , and a device 3, 4, controlled by the control signal produced by the timer device 2 and making it possible to stop the leak.  2.- Apparatus according to claim 1, characterized in that the controlled device 3, 4 comprises an alarm device 3.  3.- Apparatus according to claim 1 or 2, characterized in that the controlled device 3, 4 comprises an electrically controlled stop valve 4. 4.- Apparatus according to any one of claims 1 to 3, characterized in that it comprises a pipe 5 which can be inserted in series in the fluid circuit and having a part 5a of enlarged diameter, and in that the device flow detector 1 comprises a member 7 movable in the pipe 5 between a first position situated upstream of the part 5a of enlarged diameter in the absence of fluid flow and a second position situated in said part 5a of enlarged diameter in presence of a flow of fluid, and a proximity detector 10 placed near the second position of the movable member 7. 5.- Apparatus according to claim 4, characterized in that at least the part 5a of enlarged diameter of the pipe 5 is made of a non-metallic material, in that the movable member 7 is metallic and in that the proximity detector 10 is a metal detecting probe.  6.- Apparatus according to claim 4 or 5, characterized in that the pipe 5 is bent in a U shape. arranged vertically so that the U is inverted, and in that the part 5a of enlarged diameter is located in the first branch of the pipe 5 in the form of U considering the direction of flow of the fluid. 7.- Apparatus according to claims 3 and 6, characterized in that the electrically controlled shut-off valve 4 is placed in the second branch of the pipe 5 in the shape of a U.  8.- Apparatus according to claim 6 or 7, characterized in that the proximity detector 10 and the timer device 2 are placed between the two branches of the pipe 5 in the form of U.  9. Apparatus according to claim 8, characterized in that the pipe 5, the proximity detector 10, the timer device 2 and the electrically controlled stop valve 4 are embedded in a block of resin 19 except for the two ends 6 of the pipe 5.