FR2772917A1 - Liquid level sensor for water recycling systems, such as water closets (WC's). - Google Patents

Abstract

The sensor (2) for detection of a liquid level (3) is used for high and low liquid level detection in a water reservoir (1). It includes: - at least a water sensitive detector (4); - a receiver (5) which produces an output signal as a function of water level; - a transmitter, made up of a tube (6) filled with gas (14) such as air, whose pressure variation ensures the transmission of water level detection to the receiver (5). The sensors receiver (5) includes a pipe (6) connected to a sealed zone (7), which is limited by a membrane (8) designed to deform as the gas pressure (14) varies. An electrical contactor is controlled by the membrane (8) deformation, which causes displacement of an arm (10) on the contactor (9). The contactor (9) delivers an electrical signal dependent upon the water level.

Description

 The present invention relates to a sensor for detecting a liquid level as well as to a system for supplying liquid to a reservoir using this sensor.

 The invention will in particular allow the detection of a high level or a low level in a tank of liquid such as water and may find its application in the field of recycling of waste water or rain for example for the of a WC water tank

 The present invention therefore applies both to the field of level sensor technology and to that of the recovery and recycling of liquids such as water.

 At the present time, several types of level sensors are known which can be used in various applications and in particular that of filling water tanks for W.C.

 In this latter area, most of the current installations include a reservoir supplied with running water. A system fitted with a float makes it possible to start the supply of running water and to stop it when the tank is filled. The systems used in this case are essentially mechanical and use a float articulated by a pivoting arm allowing the opening and closing of the supply of running water.

 This type of sensor and these installations have various drawbacks. With regard to the sensor, it should first of all be noted that the implementation of these technologies with a float at the end of a pivoting arm is very imprecise and unreliable.

 Furthermore, their installation is the subject of an assembly inside the water tank and disassembly. in particular to vary the desired water level, is not easy.

 In addition, these sensors include often made bodies. either in plastic material which is not very resistant to the movements and stresses imposed by the mechanism, or in metallic material whose lifespan in an often humid atmosphere is limited.

 With regard to the installations using this type of sensor, it should essentially be noted that they have a major drawback in terms of operating cost. Running water is currently an increasingly expensive natural element for the consumer given its increasing cost price.

Consequently, a house equipped for an average family of four requires annual fees for water consumption specifically related to
WC of several hundred francs.

 To overcome the drawbacks of systems using running water and sensors fitted with floats, other installations have been implemented and essentially installations provided with waste water or rain reserves capable of supplying the W.C.

 Reserves are known in particular, supplied by means of waste water evacuation pipes, placed substantially above the W.C. tanks in order to supply them by simple gravity.

 These installations also have various drawbacks. These are notably linked to the difficulties of installing reserves significantly above W.C.

 Indeed, the supply is carried out by gravity and the water reserves must be installed either during the construction of the dwellings, or by means of quite heavy works for the existing dwellings.

 This type of installation has the disadvantage of being impractical. not very adaptable to old dwellings and also not very aesthetic because placed in visible places.

 It therefore appears that the current sensors and installations are unsatisfactory both in terms of cost and reliability.

 The present invention aims to remedy these various drawbacks and for this purpose proposes a sensor for detecting a liquid level as well as an installation for supplying liquid to a reservoir of a new and particularly advantageous design.

 One of the aims of the invention is to produce a sensor capable of being suitable for humid atmospheres, in particular by installation in water tanks but capable of delivering an output signal such as an electrical signal allowing the control of another member such as a pump.

 By achieving this aim, the sensor according to the invention allows much more diverse applications than current sensors while ensuring complete safety of the installations. especially in the case of dangerous liquids such as fuels.

The sensor according to the invention and the installations implementing it therefore exclude any electrical system in the environment of the liquid. He has for that
The advantage of transmitting level information within the sensor without requiring an electrical signal.

This advantage has various particularly beneficial consequences and in particular
no electric current is in contact with the environment of the liquid whose level is to be measured because no wire or electric organ is present in the environment of the liquid.

 - the elements of the sensor possibly to be replaced are located outside the reserves such as water tanks or tanks which makes them very accessible.

 - The invention is suitable for dangerous environments such as explosive or flammable.

 Another object of the invention is to provide a sensor and an installation having practical use and requiring little maintenance.

 The sensor has the advantage of having very reliable components and therefore having a very long service life.

 In this respect, the operation of this sensor does not generate any relative movement of the part, therefore no wear from this point of view.

 Furthermore, any metallic or electrical element is located outside of the atmosphere of the liquid, which prevents damage due for example to corrosion.

 The invention also has the advantage of not requiring any particular maintenance such as cleaning and of presenting a practical and rapid assembly or disassembly. The sensor also has the advantage of being small.

 Another object of the invention is to be adaptable to different applications.

 It has already been indicated that the sensor and the installation according to the invention could find their application in the field of supplying water tanks for toilets but also in more industrial applications. In particular, it can be used in the field of storage of various liquids such as fuels or chemicals.

 Furthermore, the variety of applications of the present invention is increased by the possibility of detecting not only a high level of the liquid but also a low or intermediate level or even a level variation.

 Another advantage is that a simple change of dimension of certain elements making up the sensor is sufficient to modify its characteristics.

 It should also be noted that the part of the sensor in contact with the liquid and that where it makes it possible to deliver an output signal can be distant from several meters or tens of meters which makes its installation even more flexible.

 Other objects and advantages will become apparent during the description which follows which is however given only for information.

The present invention relates to a sensor for detecting a liquid level. usable in particular for the detection of a high level or a low level in a water tank. characterized by the fact that it presents
- at least one detector capable of being brought into contact with the liquid
- a receiver capable of delivering an output signal depending on the level,
- Transmission means consisting of at least one pipe filled with a gas such as air, the pressure variation of which ensures the transmission of the level detection information to the receiver.

 It also relates to an installation for supplying liquid to a reservoir, using the sensor according to the invention and allowing the filling of the reservoir from a storage tank, characterized in that the sensor receiver controls the starting of a pump ensuring the filling of the tank through a supply conduit according to the information transmitted by a pipe connecting the receiver and a detector placed in the tank.

The invention will be better understood in the light of the drawing boards located in the annex and which include
- Figure I illustrating an embodiment of the sensor and the installation according to the invention.

- Figures 2 and 3 showing two particular embodiments of the detector and the transmission means,
- Figure 4 shows schematically the realization of a sensor whose receiver can be connected to several detectors.

 - Figure 5 illustrating a particular mode of installation according to the invention.

 I, e sensor (2) according to the invention ensures the detection of a level of liquid (3) as presented in particular in FIG. 1. It is according to this example a detection of a high level in the tank (1) and a low level in the tank (17). The sensor (2) delivers in these applications binary output signals according to the presence or absence of liquid (3) at the part of the sensor (2) in contact with the liquid (3).

However, the sensor (2) will also find its application for level measurements, in particular by means of a sensor delivering an electrical signal proportional to the level of the liquid (3).

 The sensor (2) according to the invention firstly comprises a detector (4). a receiver (5) as well as transmission means constituted by at least one pipe (6) filled with a gas (14).

 The detector (4) is the part of the sensor (2) capable of being brought into contact with the liquid (3) and therefore of detecting the level of the liquid. The detector may consist of a flare connected to the end (18) of the pipe (6) or even by the end (18) proper.

 In particular, it is possible to use a hollow cylindrical element attached to the pipe (6) as shown in FIG. 1.

 To avoid possible escape of gas during the insertion of the detector (4) into the liquid (3), it is possible to form closing plates (36) which limit these risks of escape. The embodiment is illustrated in FIG. 2. This authorizes correct operation of the sensor even if it is not vertical.

 The pipe (6) contains a gas (14) which may commonly be air.

This gas is likely to undergo compression or depression inside the volume of the pipe (6) and in so doing, allows the transmission of level information to the receiver (5) of the sensor (2).

 The transmission means may be constituted by any type of pipe and for practical reasons for example by a plastic pipe with a diameter of the order of a few millimeters.

 The receiver (5) transforms the level information transmitted by the pipe in the form of gas pressure variation (14) into an output signal (13).

 A particular embodiment of the receiver (5) is described more precisely below with reference to FIG. 1.

 A receiver (5) is produced comprising a sealed zone (7) wedging the gas (14) such as air by means of a membrane (8) made for example of rubber or any other elastic tight material.

 When the level of the liquid (3) increases, the volume occupied by the gas (14) decreases within the sensor (2) essentially because the volume which it occupies at the level of the detector (4) is smaller.

 This drop in volume causes an increase in the gas pressure (14) and generates a force applied to the membrane (8) of the sealed area (7). This then deforms when the gas pressure (14) increases.

 The deformation of the membrane (8) is exploited at the level of the receiver (5) by the presence of a contactor (9) such as an electrical contactor provided with a pivoting arm (10) bearing on the membrane (8) . A contactor (9) of common design of this type is shown in FIG. 1.

 The movement of the arm makes it possible to close or open the contact and therefore to control the delivery or absence of an output signal (13).

 This output signal (13) is therefore in this binary case in the form of an electrical voltage or absence of voltage. It is also possible to use an electrical member capable of delivering a signal proportional to the deformation of the membrane, for particular applications.

 To optimize the design of the receiver (5), it may include a disc (19) constituting an intermediate element between the membrane (8) and the pivoting arm (10), stops (20) preventing excessive translation of the disc (19) likely to damage the contactor (9) or to deform the membrane (8) too strongly. Finally, one or more springs (21) may be used to constitute a reminder of the displacement of the membrane and will in this case be fixed to one of its ends of the body (22) of the receiver (5) and to the other end of the disc (19) integral in translation with the membrane (8).

 It immediately appears that the length of the pipe (6) is indifferent to the operation of the sensor (2) according to the invention. Furthermore, only the detector (4) and the end (18) of the pipe (6) are placed in the environment of the liquid (3) which is particularly advantageous as has been indicated with regard to problems of electrical safety or applications to flammable or dangerous liquids.

To limit the influence of temperature on the operation of the sensor (2). a detector (4) with a much larger section than that of the pipe (6) will be produced
The device (37) illustrated in FIG. 2 will make it possible, during the rise of the liquid in the detection zone, to ensure the rise of this liquid to a level L. the gas trapped in the detector assembly (4) pipe ( 6) receiver (5) cannot escape even during high temperature increases. The detection difference will be around level L with a return to the initial state. If the liquid level drops lower than the detector there will be automatic defusing of the latter.

 The liquid (3) rises simultaneously in the orifices A and B, then fills the cavity D by passing through the pipe C as soon as the level L is reached. The liquid (3) going up in the capacity D closes the exhaust pipe E. The liquid can no longer go up in the detector (4) and will be stabilized at level L. During the descent of the liquid (3) , the cavity D is emptied via the pipes B and C until releasing the pipe E and therefore allowing the evacuation of the liquid in the detector (4).

 Another device (37) for shifting the liquid level is shown in FIG. 3. It allows, by means of a cavity D filled with liquid (3). to guarantee an operation of the sensor (2) around a substantially constant level of liquid L.

 In another embodiment illustrated in FIG. 4, a receiver (5) is connected to several detectors (4) by means of several pipes (6; 23).

 Figure 4 shows schematically the realization of a receiver connected to two pipes (6; 23). In this case, the output signal (13) is conditioned by two separate pieces of information transmitted in the form of gas pressure variation (14) through two pipes (6; 23). These two distinct pieces of information will essentially be two levels of liquid, in particular two levels of liquid (3) of a tank (17) and of a reservoir (1).

 One of the liquid levels (3) will be chosen as hierarchically priority over the other. For example, the information in the form of pressure variation ~ transmitted by the pipe (23) will constitute a necessary condition for the delivery of an output signal by the contactor (9).

 To make such a sensor (2), the receiver (5) will include two sealed zones (7; 24), one of the zones (24) being limited by an annular membrane (25) as illustrated in FIG. 4.

 The two membranes (8 .25) are therefore substantially superimposed and each connected to a pipe (6; 23).

 As before, discs (19;) may be placed on the surface of the membranes (8 25) capable of moving according to the deformation of the membranes.

 As illustrated in FIG. 4, a support element (27) is integral with one of the discs (26) and constituted for example in the form of a rod capable of coming into contact with the arm (10) of the contactor (9) in order to control the delivery of an output signal (13) according to the deformation of the membrane (25).

 The other disc (19) is in turn applied to the surface of the membrane (8) and connected to another support element (28) capable of coming into contact with the arm (10).

 The installation (30) for supplying liquid (3) to a reservoir (1) according to the invention uses the sensor (2).

 The installation (30) allows the filling of the reservoir (1) from a storage tank (31). In a particular example. the storage tank (j 1) contains waste water coming in particular from drainage pipes or rain water and allows the supply of a tank (1) corresponding to the tank of a W.C.

 According to the present invention, the receiver (5) of the sensor (2) presented by the installation (30) controls the starting of a pump (32) ensuring the filling of the reservoir (1) by means of a conduit. (33) supply. The start-up command is carried out according to the information transmitted by a pipe (6) connecting the receiver (5) and a detector (4) placed in the tank (1).

 In fact, the information transmitted by the pipe (6) corresponding to a lack of liquid (3) in the reservoir (1) is materialized by a reduction in the deformation of the membrane (8) which causes the contactor (9) to close. ) and the delivery of an output signal (13) in particular in the form of an electrical signal capable of controlling the starting of the pump (32).

 In a particular embodiment of the installation (30) according to the invention, this comprises a second detector (34) placed in the storage tank (31) and connected to the receiver (5) by a pipe (23) . The receiver used in this case is of the type presented in FIG. 4, that is to say comprising two sealed zones (7; 24).

 In this way, starting the pump (32) is only authorized if the level of liquid (3) stored in the tank (31) is sufficient.

 Indeed, when the tank (31) is empty, the annular membrane (25) is not deformed and the support element (27) pivots the arm (10) which opens the contactor (9). No signal is then delivered by the sensor (2) to the pump (32).

 On the other hand, if the level of the tank (31) is sufficient, the membrane (25) is deformed, which tends to distance the support element (27) and the pivoting arm (10). It is then the level of liquid (3) in the reservoir (I) which determines whether or not an output signal is triggered. If the level in the tank (l) is sufficient, the diaphragm (8) is deformed and the support element (28) is applied to the pivoting arm (10) cc which opens the contact and avoids any output signal (13). On the other hand, if the membrane (8) is not deformed, the disc (19) and its support element (28) no longer exert any force on the pivoting arm (10) causing the closure of the contactor (9 ) and the delivery of an output signal (13) for controlling the pump (32).

 In the particular case where the installation (30) according to the invention applies to the recycling of waste water in a toilet flush tank, the tank (31) is supplied with water through the pipes ( 36) for evacuating waste water and provided with means such as an overflow or a float plug (35) making it possible to avoid overflow of the tank (3 1).

 The supply of the reservoir (1) will in this case be carried out by controlling a pump (32), control coming from a single sensor (2) as described above or by controlling two separate sensors (2) each delivering a separate level information for the tank (31) and the tank (1).

 It appears from the present description that the sensor according to the invention is of an inexpensive design using a contactor (9) of current design and elements such as a detector (4) and transmission means which can easily be produced by plastic material. The cost of the sensor is therefore limited. Furthermore, the installation (30) can be implemented in a very practical manner, in particular by installing a tank (3 1) of limited capacity at an appropriate location in the dwelling such as a cellar. It then suffices to mount a conduit (33) connected to a pump (32) of current design to supply the reservoir (1). The receiver (5) of the sensor (2) can be placed near the pump (32) to constitute only one electrical zone in the installation (30).

 In the area accessible to the user, that is to say the W.C., any security problem is thereby eliminated.

 The comfort of use is also optimized by the silence of filling of the tank (1).

 An installation (30) is thus produced according to the invention of reduced cost price capable of saving a large consumption of running water in the dwellings.

Claims (10)

 1. Sensor (2) for the detection of a liquid level (3) usable in particular for the detection of a high level or a low level in a water tank (1), characterized in that he introduces  - at least one detector (4) capable of being brought into contact with the liquid (3)  - a receiver (5) capable of delivering an output signal depending on the level  - Transmission means consisting of at least one pipe (6) filled with a gas (14) such as air, the pressure variation of which ensures the transmission of the level detection information to the receiver (5).  2. sensor (2) for detecting a liquid level (3) according to claim 1, characterized in that the receiver (5) comprises by pipe (6) a sealed area (7) connected to said pipe (6 ) and limited by a membrane (8) able to deform according to the variation in gas pressure (14).  3. sensor (2) for detecting a liquid level (3) according to claim 2, characterized in that the receiver (5) comprises an electrical contactor (9) controlled by the deformation of the membrane (8) which generates the movement of the arm (10) of the contactor (9) said contactor (9) delivering an electrical signal (13) depending on the level of the liquid (3).  4. Sensor (2) for detecting a level (3) of liquid according to one of claims 3 there, characterized in that the detector (4) is constituted by the end (1 8) of the tgyau ( 6) or by a flare connected to this end (18).  5. Sensor (2) for detecting a liquid level (3) according to claim 4, characterized in that the detector (4) has a much larger section than the pipe (6) in order to limit the influence of temperature on the sensor (2).  6. Sensor (2) for detecting a liquid level (3) according to one of claims I to 5, characterized in that the transmission means comprise a device (37) for shifting the level of the liquid ( 3) relative to the base of the detector (4) for adjusting the sensor (2) during its installation.  7. sensor (2) for detecting a liquid level (3) according to one of claims I to 6, characterized in that it comprises several pipes (6 23) each connected to a sealed area (7 .24) of the receiver and at their other end to a detector (434) placed in separate tanks (1) or tanks (17), for the delivery of an output signal (13) depending on several levels of liquid ( 3).  8. Installation (30) for supplying liquid (3) to a reservoir, (1) using the sensor (2) according to one of claims 1 to 7 and allowing the reservoir to be filled in (I) from a storage tank (17), characterized in that the receiver (5) of the sensor (2) controls the starting of a pump (39) ensuring the filling of the tank (1) by means of a supply duct (33) according to the information transmitted by a pipe (6) connecting the receiver (5) and a detector (4) placed in the tank (1).  9. Installation (30) for supplying liquid (3) to a reservoir (1) according to claim 8. characterized in that it comprises a second detector (34) placed in the storage tank (17) and connected to the receiver (5) by a pipe (23) to authorize the starting of the pump (32) only if the level of liquid (3) stored is sufficient.  10. Installation (30) according to one of claims 8 or 9, characterized in that it allows the recycling of wastewater in a tank (1) flushing W-C. the tank (31) being supplied with water by means of the pipes (36) for evacuating wastewater or rainwater and provided with means such as an overflow or a float plug (35) making it possible to avoid its overflow when 'she is full.