Abstract:
An apparatus for continuously controlling fluid flow in a sewer conduit, comprising: a) moisture sensors detecting levels of fluid in this conduit; b) an inflatable bladder, mounted in the sewer conduit for releasably sealing in fluid tight fashion a section of this conduit; an air compressor, for inflating the bladder; and a control box including a CPU, sensitive to the moisture sensor and actuating the air compressor responsively to conduit fluid level conditions reaching beyond a preset threshold value. The performance of the apparatus is independent of the speed of fluid flow in the sewer conduit.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application is a continuation in part of U.S. patent application Ser. No. 12/885,680 filed on Sep. 20, 2010 which is integrated herein by reference. The application Ser. No. 12/885,680 was also a continuation in part of U.S. patent application Ser. No. 11/955,990, filed on Dec. 13, 2007 now abandoned. 
    
    
     FIELD OF THE INVENTION 
     The present disclosure relates to the field of fluid flow control systems concerned with fluid backup or fluid leaks, for sewer ducts, gas pipelines, and the like. 
     BACKGROUND OF THE INVENTION 
     There exists a plurality of situations wherein it is desirable to control accidental fluid backup flow in specific circumstances, or to monitor the fluid flow in pipes. 
     In a building or other structures serviced via an underground sewer line, it sometimes occurs that the main sewer line or the branch line leading from the building to the main sewer line becomes clogged. Indeed, the problem of basement flooding from sewer line water backup flow has become prevalent in recent years. The backup may be caused by a variety of problems including when the flow capacity of the sewer system is exceeded by the rain water inflow rate into the system. 
     The risk of water backup is present in most storm sewer systems where the storm sewers are rarely of a sufficient size to accommodate unusually heavy rain storms. This risk is sometimes present in sanitary sewer system where there is a water leakage into the sewer system through manholes, cracks in sewer line joints or where improper roof down spout connections are made to the system which normally should carry only the water and sewage draining from sinks, toilets, washing machines drain lines and basement floor drains. 
     Clogging of the sewer line may be caused by many factors including broken or misaligned pipes. Such broken or misaligned pipes present projections, ridges or sharp bends on which bulk material hangs up and causes a nucleus fore clogging. Other times, roots from surface plants invade the pipe in search of moisture which may be leaking from poorly formed joints in the pipe and these roots also can form the nucleus of the clog in the pipe. Whatever the cause of the clog, the effect is that the sewage becomes backed up in the line and eventually the backflow will overflow from the fixtures and drains in the building. 
     Modern sewer systems are equipped with clean out pipes or outlets. The clean out is accomplished by inserting a Tee or Y joint in the sewer line just outside the building or in the basement. Leading from the Tee or Y joint is a vertical or near vertical clean out pipe which is kept or plugged near the ground surface. While this type of clean out allows for access to the sewer line for removal of clog, it does not prevent the backflow or sewage through the sewer line which will eventually overflow from the fixtures or drain inside of the building. 
     Backup problem in sanitary sewer lines leading to an individual home can be substantially eliminated by the application of a backflow preventing valve in the pipe line extending between the home and the underground sanitary sewer line running along the street involved. When backup water pressure builds up, the backflow preventing valve is closed or closes to prevent the water in sanitary sewer lines from backing up into the user&#39;s home. 
     However, many home owners simply do not wish to incur such systems. Indeed, conventional flow protection usually consists of a simple check valve, more particularly a flap valve mounted inside the sewer duct, which functions as a pivotable gate providing for unidirectional flow of the fluid in the sewer line away from the source. However, these pivotal gates are only efficient when the fluid flow inside the sewer is at fast speed, since the gate will then be forcibly pivotally biased against its annular seat inside the sewer duct by the hydrodynamic forces. Such pivotal gate valve systems are however ineffective in conditions of sewer duct clogging, since the fluid level inside the sewer duct raises quite progressively, and the fluid flow speed is usually small, which would not provide a hydrodynamic force suitable for pivotally biasing the pivotal gate against its annular seat in a fluid tight fashion. 
     Inflatable bladders may be used in place of pivotal gate valves, although these bladders create a phenomenon of fluid flow turbulence. When these bladders are in their inoperative deflated condition, they remain in a radially inwardly projecting condition inside the sewer duct passage that constitutes a partially obstructive element. Moreover, such inflatable bladders may require manual handling to be deflated. 
     Furthermore, most conventional fluid backflow mitigating prior art systems are not efficient in early detection of fluid and thus are relatively unreliable and inefficient. 
     SUMMARY OF THE INVENTION 
     Accordingly, there exists a need for an improved fluid backup preventing system that can be used in a variety of situations such as in sewer lines to prevent sewer backup into basements. 
     It is an aim of the present disclosure to provide an assembly of a conduit in which a fluid flows and of a system for blocking the conduit upon detecting a problem condition for the fluid, comprising: a conduit defining an inner cavity in which the fluid flows; an inflatable bladder adapted to be mounted in a section of the inner cavity of the conduit, the inflatable bladder inflatable/deflatable between a deflated inoperative condition and an operative inflated condition in which the bladder is inflated for sealingly closing the conduit section; at least one sensor assembly comprising a pair of wires connected to a sensor adapted to detect the problem condition of the fluid and positioned in the conduit on at least one side of the inflatable bladder, and beyond a contact area between the inflatable bladder and the conduit, the side being that related to the problem condition of the fluid; a pressure system in fluid communication with the inflatable bladder to inflate the bladder to the operative inflated condition, and to deflate the bladder; and a processor unit for actuating the pressure system when the problem condition is detected by the at least one sensor, and for subsequently deflating the bladder when the problem condition is not detected wherein said sensor assembly is at least partially covering and overlapping the inflatable bladder. According to another aspect of the present invention, the sensor assembly may be at least partially integrated to the bladder. 
     It is a further aim of the present disclosure to provide a novel system for blocking fluid pipes upon detection of a given condition of fluid flow in the fluid pipe. 
     In accordance with the teachings of the disclosure, there is disclosed an apparatus for continuously controlling fluid flow in a conduit, comprising: a) sensor means, for detecting the level of fluid in this conduit; b) conduit sealing means, for releasably sealing in fluid tight fashion a section of this conduit; c) main power means, for actuating said sealing means; and d) control means, sensitive to said sensors means and actuating said main power means responsively to a conduit fluid level reaching beyond a threshold value; wherein the performance of said control means is independent of the speed of the fluid flow in the conduit. In addition, the present system may comprise a splash guard which comprises a deflector, preferably impermeable, protecting the sensors means from unwanted splashes of fluid onto the sensors which would otherwise trigger a signal to inflate the bladder in a situation which would not justify same. The deflector is disposed partially underneath the sensor assembly to prevent the unwanted activation of the sensors in the event of a splash of fluid onto the sensor assembly not caused by said problem condition. The deflector is configured to stop such splashes while allowing the sensors to operate if the level if liquid in the conduit reaches the sensors. Such a splash of fluid may happen when a high volume of fluid is flowing in the conduit during normal use. However, the high quantity of fluid should not trigger the sensors as the conduit is functioning normally and no backup fluid is present in the conduit. This feature of the system allows proper functioning of the fluid backup prevention system. The splash guard prevents the triggering of false signals due to bursts burst of fluids in the conduit. 
     Preferably, said control means are further sensitive to the deactivation of said main power means, and further including power backup means, whereupon said control means automatically activating said conduit sealing means independently of fluid level in the conduit when said main power means becomes deactivated. Said control means preferably further includes a self test function for the power backup means that checks at predefined regular time intervals if said conduit sealing means is operative, and further including alarm means (sound, light or otherwise) issuing an alarm detectable by the apparatus user upon said control means detecting that said power backup means has become inoperative. 
     Preferably also, said conduit sealing means includes an inflatable bladder for mounting into the conduit section, and further including inflating means for inflating the bladder between a deflated inoperative condition and an operative inflated condition for sealingly closing the conduit section. Said inflatable bladder could then have in its operative inflated condition a portion of toroidal shape for sealingly engaging the conduit section. Said bladder could be elongated with two opposite end portions each forming a convex half sphere. Said sensors means could include at least one pair (preferably two pairs) of positive and negative electrical cables, said cables extending between said control means and said bladder, and moisture sensors mounted at the end of said cables located about said bladder. Said moisture sensors are preferably covered by non corrodible fluid proof conducting alloys, and uses electrical conductivity measures for determining the fluid level in the conduit. 
     The disclosure also relates to a method for operating an apparatus for continuously controlling fluid flow in a conduit, the apparatus of the type comprising sensor means for detecting levels of fluid in this conduit, conduit sealing means for releasably sealing in fluid tight fashion a section of this conduit, main power means for actuating said sealing means, and control means, sensitive to said sensors means and actuating said main power means responsively to a conduit fluid level reaching beyond a threshold value so that the performance of said control means is independent of the speed of the fluid flow in the conduit; wherein the method comprises the following steps: 
     a) said sensor means sensing a fluid level beyond said threshold value; 
     b) said control means analyzing data coming from the sensors means; and 
     c) said control means actuating said conduit sealing means responsively to said data. 
     Preferably, there is further included the following steps: 
     d) having said sensor means detecting fluid level returning to condition short of said threshold level; 
     e) said control means analyzing this latter data from said sensors means; and 
     f) said control means deactuating said main power means responsively to the latter data. 
     The disclosure also relates to the combination of sewer conduit for fitting to a dwelling, said conduit having a clean-out duct mounted transversely thereto and opening into said fluid flow channel, and the above-noted apparatus. 
     The disclosure also relates to a method for installing and releasably locking a valve apparatus inside a clean-out duct of a sewer conduit, the valve apparatus for continuously controlling fluid flow in the conduit, the apparatus including: a) sensor means, for detecting the level of fluid in this conduit; b) conduit sealing means, for releasably sealing in fluid tight fashion a section of this conduit; c) main power means, for actuating said sealing means; and d) control means, sensitive to said sensors means and actuating said main power means responsively to a conduit fluid level reaching beyond a threshold value; wherein the performance of said control means is independent of the speed of the fluid flow in the conduit, the apparatus further including a discoid support member releasably mounted inside the clean-out duct, a hang screw rod assisting in the positioning of said discoid support system in said clean-out duct, said sealing means being an inflatable bladder, said inflatable bladder in deflated configuration movable to a set position inside the clean-out duct, and further including retaining clips to prevent accidental release of said apparatus from its said set position, wherein said method comprises the following steps: a) said hang screw rod moving the said apparatus inside said clean-out duct; and b) said inflatable bladder in deflated configuration emitting a sound cue emitted through said rod, indicating said deflated bladder has reached its said set position inside the clean-out duct. The sound cue may be the sound occurring by the deflated bladder pops out of the clean-out duct, which sound may be transmitted partially by the rod. 
     Preferably, said sensor means could then include power cables and, upon release of said valve apparatus being required, further including the following step: c) pulling out said apparatus from said fixed position in said clean-out duct, by upwardly pulling said power cables. 
     Preferably, said clean-out duct defines an annular recess fully clearing said channel, said conduit sealing means including an inflatable bladder mounted into said annular recess, and inflating means for inflating the bladder, said bladder when in an inoperative condition remaining fully inside said annular recess and fully clearing said channel to prevent fluid flow turbulence in the conduit when deflated, and when in an operative inflated condition further extending radially into said channel and fully sealingly closing said channel. 
     The present disclosure therefore provides a system for blocking fluid flow within a conduit and utilizing an inflatable component which is located permanently in the conduit or a section that allows access to the conduit wanted to protect from fluid flow backup. An electrical moisture sensor capable of rapidly and accurately detecting the fluctuation of fluid in a conduct and transmitting the information to the circuitry forms part of the disclosure. 
     A circuitry receives the information from the moisture sensors and then decides whether or not it will activate the inflatable component to prevent fluid backup. 
     A backup battery of the circuitry is also provided, in case of electrical mains supply blackout, so as to enable relying on backup battery that will automatically activate the inflatable component by default, independently of fluid level inside the sewer conduit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1 : is a longitudinal sectional view of an intermediate section of sewer conduit, showing a fluid backup preventing system in accordance with an embodiment of the present disclosure mounted on a transverse clean-out duct into the sewer conduit, the inflatable bladder being shown in a retracted deflated inoperative position inside the clean-out duct; 
         FIG. 2 : is a view similar to  FIG. 1 , but with the inflatable bladder being inflated in a fully inflated operative configuration, extending radially into the sewer conduit and fully closing a section of the latter; 
         FIG. 3 : is a partly schematic enlarged plan view of the control box of a fluid backup preventing system in accordance with an embodiment of the present disclosure; 
         FIG. 4 : is a partial plan view of a control panel part of the fluid backup preventing system of  FIG. 3 ; 
         FIG. 5 : is a partial enlarged perspective view of a pneumatic tube and electrical wire assembly from the fluid backup preventing system of  FIG. 3 ; 
         FIG. 6 : is an enlarged view of the area circumscribed by an ellipse in  FIG. 5 ; 
         FIGS. 7 and 8 : are partial elevation views of the inflatable bladder, suggesting the adjustable nature of cable sleeve connection between electrical circuits and the inflatable bladder of the fluid backup preventing system of  FIG. 3 ; 
         FIG. 9 : is a partial perspective view of the inflatable bladder, showing in phantom lines the fluid sensor part inside the bladder of a fluid backup preventing system of  FIG. 3 ; 
         FIG. 10 : is a enlarged cross-sectional view taken along lines  10 - 10  of  FIG. 1 , showing how the inflatable bladder clears the sewer conduit in the retracted inoperative condition thereof; 
         FIG. 11 : is a partly broken perspective view of the sewer duct, showing the inflatable bladder in its operative fully inflated condition, similarly as in  FIG. 2 ; 
         FIG. 12 : is an enlarged view of a discoid support system, in accordance with another embodiment of the present disclosure; 
         FIG. 13 : is a perspective view of the discoid support system of  FIG. 12  with a bladder thereon; 
         FIG. 14 : is an enlarged longitudinal sectional view of the discoid support system from  FIG. 12 ; 
         FIG. 15 : is a block diagram showing a plurality of the bladders in series on a single conduit  14  and controlled centrally; 
         FIG. 16 : is a block diagram showing a plurality of the fluid backup preventing system used controlled centrally; and 
         FIG. 17 : is a view similar to  FIG. 1 , but with the inflatable bladder being inflated in a fully inflated operative configuration, showing sensors remaining exposed while bladder is inflated. 
         FIG. 18 : is a partial enlarged top view of an embodiment of the fluid backup prevention system wherein the system comprises a deflector preventing unwanted trigger of the system in the event of a splash of fluid. 
         FIG. 19 : is a partial enlarged lateral view of the embodiment of  FIG. 18 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1 and 2 , there is shown a fluid backup preventing system  11  in accordance with an embodiment of the present disclosure mounted into a clean-out duct  12  transversely opening into the channel  13  of sewer conduit  14 . A fluid F, for example a liquid, may flow inside channel  13  at a low fluid level L 1 , along a normal flow direction D 1 . Although the present disclosure refers to the positioning of parts of the system  11  in the clean-out duct  12 , it is pointed out that any other arrangement may be used for the positioning of fluid blocking components in the channel  13  of any type of conduit  14  (e.g., gas pipeline). 
     The clean-out duct  12  is preferably provided with a distal threaded segment  12  a so as to threadingly receive a mounting cap  16  provided with a cap aperture  18  extending centrally there through. The cap aperture  18  is configured and sized so as to fittingly receive at an intermediate section a cable sleeve  20  for protectively enclosing various operative cables (pneumatic line  36  and electrical wires  43 ,  43 ′,  43 ″,  43 ′″) hereinafter disclosed and also for supporting the valve components in a suitable overlying relationship relative to the sewer conduit  14 . Wireless technology may be used as well instead of having electrical cables. In such a case, the remote unit is separately powered. 
     As mentioned previously, it should be understood that although the fluid backup preventing system is shown in  FIGS. 1 through 11  and hereinafter disclosed as being used in the context of sewer conduits, it could also be used in various other contexts without departing from the scope of the present disclosure. Among other uses, it is considered to use the system  11  to block gas pipelines in case of leaks. For instance, the system  11  may detect the level of a gas in a pipeline, and block the pipeline if the gas level is outside given thresholds. According to another embodiment, the system  11  detects the presence of unwanted fluids in the channel  13 , and may block the channel  13 . The system  13  may therefore be used to prevent the spill of hazardous matters in the environment. 
     The sleeve  20  is connected at a proximal end portion thereof to a casing  22  by a suitable connecting ring  24  and at a distal end thereof to a valve means  26 . The valve means  26  preferably takes the form of an inflatable component, typically an inflatable bladder  30  at least partially mounted within a bladder sleeve  28 , for instance as shown in  FIG. 2 . Bladder  30  is mounted inside clean-out duct  12 . The bladder  30  is adapted to be inflated to an inflated configuration illustrated in  FIGS. 2 and 11  wherein its inflated flow-obstructing section  32  projects radially inwardly of channel  13  and abuttingly fully contacts the interior wall  14 A ( FIG. 1 ) of the duct  14  in a generally fluid tight fashion so as to prevent or reduce accidental backflow into the latter when given conditions such as fluid overflow are met. That is to say, fluid flow direction D 2  ( FIG. 2 ) is prevented, being a reversal of the direction of original normal fluid flow direction D 1  ( FIG. 1 ), which is associated with a fluid overflow condition of fluid F inside sewer duct  14  ( FIG. 2 ). 
     The bladder  30  further includes a distal contacting portion  34  located opposite its flow obstructing portion  32 , which is adapted to inflate to a contacting configuration also shown in  FIG. 2  when the pre-set fluid overflow condition is met. 
     As shown in  FIGS. 3 and 5 , the bladder  30  is pneumatically coupled to pneumatic circuitry located within the casing  22 , by an outer pneumatic line  36  protectively enclosed within the sleeve  20 . The outer pneumatic line  36  extends integrally into an inner pneumatic line  38  protectively enclosed within the casing  22 . The inner pneumatic line  38  is pneumatically coupled to a pneumatic compressor  40  (or to any other source of pressurized air) through a conventional pressure regulator  42  having a built-in automatic shut off function and a conventional pneumatic distributor  44  typically having three-way and two-position functions so as to allow the selective inflation and deflation of the bladder  30 . Although not shown, the bladder  30  may use the monitored liquid to become inflated. For instance, if the liquid being monitored is water, the bladder  30  may collect water (e.g., using a pump and line) in the conduit  14  and fill the bladder  30  therewith. 
     Referring to  FIGS. 5 to 9 , the sleeve  20  also protectively encloses a contact sleeve  46  enclosing at least one sensor assembly comprising at least one pair of wires  43  and  43 ′, where one is negative and the other positive, and preferably two pairs of wires  43 ,  43 ′, and  43 ″,  43 ′″ for redundancy purposes (with additional wires as back-up if necessary), to be used with a corresponding number of moisture sensors  48 . When the moisture level is high enough, the two pairs of electric wires  43 ,  43 ′, . . . will start conducting electric current. By moisture level, it is meant a gaseous moisture level, or a liquid moisture level, depending on the type of fluid circulating in channel  13 . The wires  43 ,  43 ′,  43 ″ and  43 ′″ could use a different type of sensor depending on the type of fluid that needs to be detected, for example a methane sensor or other gas sensors could be combined with the existing moisture sensor  43  and  43 ′. Moreover, the sensors could be used to monitor different characteristics of the flow, such as speed and pressure. It is considered to use ultrasound sensors for such monitoring. The sensor assembly is preferably at least partially covering and overlapping the inflatable bladder  30 . According to another embodiment, the sensor assembly could be at least partially integrated to the inflatable bladder. 
     According to an embodiment, the present system may comprise a splash guard  88  (shown in  FIGS. 18 and 19 ) which comprises a deflector  88 , preferably impermeable, protecting the sensors assembly from any splash of fluid which is not the result of. Such a quick splash of fluid may happen when a high volume of fluid is flowing in the conduit. However, the high quantity of fluid should not trigger the sensors  48  if the conduit is functioning normally and no backup fluid is present in the conduit. This feature of the system allows the proper functioning of the fluid backup prevention system. The splash guard  88  prevents the triggering of false signals due to bursts of fluid in the conduit. The at least partially protecting of the sensor assembly is achieved in a way that prevents sudden bursts of fluid to trigger the inflation of the bladder. As such, the sensor assembly may be at least partially protected while allowing fluid contact between the sensor assembly and the fluid inside the conduit when a fluid back flow occurs in the conduit. The cover should be installed in a way that prevents the triggering of a signal when a splash occurs but would still allow the triggering of the inflatable bladder when the sensors  48  are, for instance, immersed by the fluid back flow in the conduit. 
     According to an embodiment, these electrical sensors are of the type working at a low level of voltage, for example at the 0.3 volt and 0.1 Ampere range. According to one embodiment, the moisture sensors are mounted about an intermediate section  34  of the inflatable bladder  30 , forming the electrical ends of wires  43 ,  43 ′,  43 ″,  43 ′″. Sensors  48  should preferably be covered by a non-corrodible fluid proof conducting alloy. The sensor assembly comprising the moisture sensors  48  are preferably welded to the bladder  30  by a conventional sonic welding method or any other suitable method, so that these wire portions  43 A,  43 B become integral to and concealed by the wall of inflatable bladder  30  about bladder portion  30 A. Only the end moisture sensor tips  48 ,  48 ′,  48 ″,  48 ′″, project freely through the intermediate wall of bladder  30 , at a peripheral intermediate location of bladder  30  opposite outer end  34  of bladder  30 . 
     The sensor(s)  48 , whether it is a moisture level sensor, a liquid detector, a gas detector, or any other fluid detection unit, is strategically positioned on the side of the channel  13  from which the problematic fluid arrives. In the embodiment of  FIGS. 1 and 2 , the problematic fluid is the backflow of water, for instance from the sewer system. Accordingly, the sensor(s)  48  is at least positioned on the side of the sewer system. 
     By being positioned on the side of the problematic fluid, the sensor(s)  48  quickly detect the problematic fluid (i.e., level outside of threshold, etc.), but will keep on detecting the problematic fluid while the bladder  30  is inflated. In an embodiment illustrated by  FIG. 17 , the bladder  30  is sized so as not to impede the detecting operation of the sensor(s)  48 . When the problematic fluid returns to a level within the threshold, as managed by the central processing unit described hereinafter, the bladder  30  may automatically be deflated once the sensor(s)  48  no longer detects the presence of the fluid. The automatic deflation advantageously facilitates the use of the system  11 , as the clean-out duct  12  does not need to be opened to determine whether there remain issues with the problematic fluid. 
     As shown above, the sensor(s)  48  may be positioned on the inflatable bladder  30 , or may be placed in the channel  13  separate from the bladder  30 , such that the fluid detection is not altered by the presence of the bladder  30 . The sensor assembly is preferably at least partially covering and overlapping the inflatable bladder  30 . According to another embodiment, there may be sensors  48  on both sides of the bladder  30 . For instance, one of the sensors  48  may detect a sewer fluid backup on one side of the bladder  30 , while another one of the sensors  48  on the other side of the bladder  30  may detect hazardous matters or substances, to prevent a spill in the sewer. 
     The type of bladder  30  that will be used (e.g., bladder material, thickness, coating), and the inflation pressures will depend on the application in which the system  11  will be used. For instance, it may be required to use specific types of rubbers in view of the potential presence of hazardous materials in contact with the bladder  30 . 
     Returning to  FIG. 3 , wires  43 - 43 ′″ extend internally into an internal contacting sleeve section  50  protectively enclosed within the casing  22 . The wires  43 - 43 ′″ are electrically coupled to both a water sensor unit  52  and a programmable central processing unit (CPU)  54 . CPU  54  preferably takes the form of an electronic card. The electronic card  54  is electrically coupled through an internal connecting wire  56  to a relay component  58 , and to the various afore-described components of the system  11  (e.g., compressor  40 , pressure regulator  42 , pneumatic distributor  44 , etc. . . . ). An alarm means preferably of the audible piezo type  60  is further operationally mounted within the casing  22  to CPU  54 . 
     The power to the components within the casing  22  is provided by a battery type component  62  being chargeable through a battery charger and converter component  64  preferably of the 120 volt/12 volt DC type. There may also be a redundant battery  62  to ensure that the system  11  does not run out of power. Moreover, the battery  62  may be sealed to be replaced underwater. A transformer is adapted to be plugged into a conventional external mains electrical wall outlet through the use of a conventional male plug  66 . 
     In the event that the system  11  operates on battery power for instance because of a power outage, the system  11  may operate in a low-consumption mode. In such a mode, the various powered components of the system  11  go in standby mode if possible. For instance, a display panel may automatically shut down unless activated by a user. In the low-consumption mode, the system  11  keeps only the primary functions in operation, such as the monitoring via the sensor  48 . 
     An outlet cable  68  is electrically coupled to the relay  58  at a proximal end thereof and at a distal end thereof to a display panel  70  ( FIG. 4 ) mounted on the cover of the casing  22 , or to other systems  11 , or to a main unit as described hereinafter. Moreover, the outlet cable  68  may be connected to a pump, to the main water supply or the like, or any other actuator of the flow in the conduit  14  to stop the pump or the like if a condition is detected. The display panel  70  preferably includes a first display area  72  for providing visual cue as to the inflation status of the bladder  30 , a second display area  74  providing visual cue information on the moisture detection status, a third visual display area  76  for providing visual cue as to the working status of the system as whole, and a fourth display area  78  adapted to provide visual cue indication preferably with a three color code as to the condition of both the battery component  62  and charger component thereof. 
     A first control button  80  is provided for allowing the reset of the internal clock conventionally integral to the CPU  54 , a second button control  82  is provided for setting of the internal clock, a third control button  84  is provided for manual testing of the system; while a fourth control button  86  is provided for stopping the audible alarm. An external port  90  (e.g., usb port, etc) may be provided to connect the system  11  to any network (as explained hereinafter) or to any other component (e.g., alarm system, internet). 
     It should be understood that various modifications can be made to the control panel  70  without departing from the scope of the present disclosure and that the herein above description only refers to an example of such display panel  70 . 
     In use, the sensors  48  are adapted to sense moisture or a gas and/or detect by physical engagement with a liquid inside sewer conduit  14  a preset level and, once a moisture/gas upper threshold level or liquid detection has been reached, to activate the air compressor  40  so as to inflate the bladder  30 . The sensor(s)  48  may stay in a detection mode (e.g., continuously, periodically) while the bladder  30  is inflated (e.g.,  FIG. 2 ). When the detected fluid level returns to the acceptable threshold level, the central processing unit  54  actuates the pneumatic distributor  44  to deflate the bladder  30 . Any appropriate type of valve or pump may be used as an alternative to the pneumatic distributor  44 , to release the pressure in the bladder  30 , and to ensure the bladder  30  returns to its contracted state in the intermediate section  34  (e.g.,  FIG. 1 ). The bladder  30  may be inflated by way of a normally closed valve (e.g.,  44 ) when appropriate. In such a case, the bladder  30  inflates in the absence of a regular signal to the normally closed valve. 
     The deflation air may be used as a cleaning air stream for the sensor(s)  48 . In such a case, appropriate valves and conduits are provided to direct the deflation air on the sensor(s)  48  for cleaning purposes. Alternatively, a separate line connected to the pressure source may be provided for this purpose. 
     The central processing unit  54  preferably has a built-in self-test feature that periodically measures the conductivity of the moisture sensor  48 , and/or could activate the compressor  40 , so as to ensure that the latter maintains a predetermined pressure inside the bladder  30 . The self-test also preferably includes monitoring of the battery  62  and of the battery charger  64 . The self-test feature ensures that the battery  62  is sufficiently charged to allow the full deployment of the inflatable bladder  30  in case there is a mains electrical input power blackout. Another feature of self-test is the partial inflation of the bladder  30 . The pressure in the pneumatic line  38  may be monitored during the partial inflation to ensure that the bladder  30  inflates. According to an embodiment, if the measured pressure does not reach a predetermined threshold or slowly decreases after having reaching a threshold, there may be a leak in the pneumatic line  38  or in the inflatable bladder  30 , prompting the CPU  54  to indicate an error. Moreover, if the threshold is reached too quickly, the pneumatic line  38  may be blocked or the inflatable bladder  30  may not be inflating. 
     Preferably and as illustrated in  FIGS. 10 and 11 , the section  32  of the inflatable bladder  30  has a toroidal shape once inflated, for releasably sealing the sewer duct  14 , and assisting in hydrodynamic fluid management. Preferably, the opposite ends of the longitudinal axis of the toroidal bladder  30  each form convex half-spheres  32 A,  32 B, for optimal hydrodynamic fluid flow management. 
     Preferably and as illustrated in  FIGS. 12 and 13 , to facilitate handling of bladder  30 , there is provided a discoid support system  92  which is installed transversely inside clean-out duct  12  at the inner end thereof opposite outer closure cap  16 . The discoid support system illustrated in  FIG. 12  is spacedly proximate to the main conduct  14 . Access to the free top face of discoid support system  92  is easily achieved simply by removing screw cap  16 , and by an operator reaching out with his/her arm through the clean-out duct  12  for maintenance thereof. 
     The inflatable bladder  30  peripherally abuts against and is fixedly mounted to the under face of discoid support system  92 , with an annular plenum  112  formed between flanges of the discoid support system  92 , such as flange  110  (and peripheral edges  114  and  116 ). The discoid support system  92  with two facing half-moon holes  96 ,  98  comprising therebetween a hang screw rod  124  with threading  124   b  for positioning the discoid support system  92  inside the clean-out duct  12 . An air valve with port  118  may be provided on the disk of the system  92  to inflate the inflatable bladder  30  to the inflated condition, with a portion thereof shown at  120  as protruding inside the bladder  30 . An air valve system anchor proximate assists in the positioning of the present discoid support system. The sensor cable connectors  46  (see  FIG. 6 ) are inside a sheathed anti-corrosive cable that reaches the sensors  43 - 43 ′″ that are inside the inflatable bladder  30  at its extremity. The present discoid support system  92  is solid, light weight, and does not require any measurements for its installation, since a sound cue, for example a “click” sound, is felt thru the installation rod that reveals it has reached its operational set position in the clean-out duct  12 , as shown in  FIG. 12 . This sound cue comes from the shape of the inflatable bladder  30 . The discoid support system is readily removed from its set position inside the clean-out duct  12  by first pulling the clips of a power cable protection to unfix and upwardly pullback the discoid support system  92 . Alternatively, the inflatable bladder  30  may be provided with chains or the like to pull the bladder  30  out of engagement with a pipe. 
     In  FIG. 14 , the discoid support system  92  comprises a fluid port  122  for the inflation/deflation of the annular chamber  132 , to seal off any gap between the outer periphery of the bladder  30  at the discoid support system  92  and the pipe. As an alternative to this embodiment, the inflatable bladder  30  may simply be sized so as to be obstructing the pipe when inserted therein, with the inflatable bladder  30  consisting primarily of a rubber material. 
     Referring to  FIG. 15 , there is illustrated a plurality of the bladders  30  interconnected in series, and controlled centrally by a single CPU  54  ( FIG. 3 ) in casing  22 . The bladders  30  are interconnected by appropriate lines and cables in the cable sleeves  20 . Accordingly, by the use of a plurality of the bladders  30  on a single conduit  14 , numerous levels of safety may be provided. There may be a protocol among the various bladders  30 , such that the detection of a condition outside the threshold values for any one of the bladders  30  results in the inflating of all bladders  30  by the CPU  54 . Moreover, the protocol may be such as to automatically inflate any one of the bladders  30  if a related one of the cable sleeves  20  is sectioned. 
     Referring to  FIG. 15 , a plurality of the systems are connected to a main controller  150 . The main controller  150  is strategically positioned to obtain a global view of a network of conduit. For instance, the systems  11  of  FIG. 15  are positioned in various conduits of a sewer, with the main controller  150  capable of identifying a global flooding condition from the monitoring of each of the systems  11 . The main controller  150  has the capacity of actuating each of the systems individually, to manage the flow of liquids in the sewer system. 
     The present disclosure provides an improved fluid backup preventing system. Advantages of the present disclosure include the fact that the system in accordance with the present disclosure may be readily adapted to existing sewer conduits without the need for special tooling, manual dexterity or other expensive commodities. 
     Also, the present disclosure provides a built-in sensing means for actuating the valve in predetermined conditions. Furthermore, the present disclosure provides a system having a self-checking feature so as to improve overall reliability. 
     Also, the present disclosure uses a duct sealing means that is deformable so as to provide an efficient seal even in situations wherein the sewer conduit is warped or otherwise damaged. 
     Furthermore, the present disclosure provides a built-in audible warning means for alerting the dwelling occupants of the flood threatening situation.