Abstract:
An exemplary embodiment providing one or more improvements includes a positive acting sensor which detects the flow of water through a flat roof secondary or emergency roof drain. In embodiments a signal from the sensor is conveyed by a conductor or by wireless means to an alarm box. In embodiments the alarm box provides an audible and or a visual signal indicating a minimal water flow in the secondary drain.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    Not Applicable 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable. 
       THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT 
       [0003]    Not Applicable. 
       REFERENCE TO A “SEQUENCE LISTING,” A TABLE, OR A COMPUTER PROGRAM LISTING APPENDIX 
       [0004]    Not Applicable. 
       BACKGROUND 
       [0005]    This invention relates to the detection of flow in secondary or back-up flat roof drain systems. 
       BACKGROUND 
     DESCRIPTION OF RELATED ART INCLUDING INFORMATION DISCLOSED UNDER 37 CFR 1.97 AND 37 CFR 1.98.  
       [0006]    Flat roofs do not enjoy the intrinsic drainage of precipitation of sloped roofs. Flat roofs would accumulate such precipitation without the incorporation of multiple drains, termed primary drains. Such drains are equipped with strainers to exclude debris such as leaves and branches and ice, thereby preventing clogging of the drain. Nevertheless, primary drains do become blocked by debris and ice, or may simply be overcome by excessive precipitation, with the risk of overcoming the structural integrity of the roof. Secondary or emergency drains are also provided to relieve the water level when the primary drains become clogged and the water level on the roof raises. It is important to building users to become aware the a secondary drain is operating removing water from the roof, so the user can go to the roof and unblock the primary drains or so the user can appreciate the incapacity of the primary system to control the rainwater overload on the roof. Embodiments of the present application provide indication to the user that the secondary drain is in operation. 
         [0007]    Some engineers and municipalities were providing or requiring secondary drain systems before they were required by code. The addition of a secondary system proved a sound engineering decision as the importance of this secondary system is understood and recognized by all codes. The need to know when the secondary systems are in actual use is important as it alerts the building owner of a potential problem with the primary system, whether it be a problem with debris at the roof drain dome or an actual stoppage in the piping system. One major code requires the secondary system be discharged separately and at a location where it can be observed by pedestrians. Also, inclement weather can reduce the number of knowledgeable pedestrians around a given building that would notice emergency overflow drains in operation. Therefore, a third overflow indicator would be advisable. 
         [0008]    U.S. Pat. No. 4,248,258 discloses a flat roof solar powered auxiliary drain system having multiple modules which drain various sections of a roof. An electrical probe sensor activates pumps when water on the roof reaches a predetermined depth. 
         [0009]    U.S. Pat. No 4,596,266 discloses a system for removing rain water from hydrocarbon storage tank floating roofs. A water sensor uses electrical conductive means to detect the presence of water. 
         [0010]    U.S. Pat. No. 5,218,346 discloses a low volume flow meter. A watermill-like device rotates in the presence of flow. 
         [0011]    U.S. Pat. No. 5,378,356 discloses a flat roof drain structure with a drain and an overflow drain. 
         [0012]    U.S. Pat. No. 5,864,287 discloses a system for monitoring the operation of sensors in a fire-suppression system in which flow is sensed. A paddle positioned transverse to the direction of fluid flow in a conduit is moved by fluid flow, stimulating a resulting electrical signal. 
         [0013]    U.S. Pat. No. 6,594,966 discloses a bi-functional roof drain which combines in one structure a primary drain outlet and a backup drain pipe. 
         [0014]    U.S. Pat. No. 6,696,965 discloses a rotary paddle bin monitor in which a normally freely rotating paddle is inhibited from rotating by the accumulation of dry bulk material in a bin, thereby causing the rotation of a motor housing and stimulating a magnetic sensor. 
         [0015]    U.S. Pat. No. 6,786,091 discloses a mechanical process for detection of overflow of a gutter. 
         [0016]    U.S. Pat. Applic. Pub. No. 2006/0033629 discloses a overflow sensor for a backup roof drainage system in which the flow of water in the system is detected by the conductivity of water flowing over electrodes embedded in a pipe. 
         [0017]    The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings. Embodiments of the present application provide solutions to the problem of detecting primary drain blockages which are effective, reliable, and inexpensive. 
       BRIEF SUMMARY 
       [0018]    The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tool and methods which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the above-described problems have been reduced or eliminated, while other embodiments are directed to other improvements. 
         [0019]    Embodiments include an alarm system for detecting the flow of water in a secondary emergency overflow roof drainage system having at least a portion of its conduit in a horizontal orientation, the alarm system comprising, a flow sensor in the horizontal conduit of the roof drainage system comprising, a flow switch with a switch base, the flow switch attached to the horizontal conduit wall with the switch base extending into the conduit lumen. A flow sensor vane, the vane pivotally connected to the switch base, the vane extending from the switch base into the lumen of the conduit, the length of the vane approximating 90% of the diameter of the conduit. The vane is oriented in the conduit so the flow of water in the conduit causes the vane to swing about the pivot connection. The flow switch converts the vane position into an electrical value. An alarm box provides a visual or audible signal in response to a predetermined electrical value, and conductor means convey an electrical value from the flow switch to the alarm box. In embodiments, notification of flow in the secondary emergency overflow roof drainage system is by both visual and audible alarms. 
         [0020]    In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following descriptions. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a cross-section of a flat roof building showing a primary drain to the sewer system and overflow drain with an embodiment flow detection system. 
           [0022]      FIG. 2  is a cross-section of a flat roof building showing a primary drain to the sewer system and overflow drain which use a common drain conduit with an embodiment flow detection system. 
           [0023]      FIG. 3A  is a cross-section of an horizontal conduit taken along the conduit length showing an embodiment sensor. 
           [0024]      FIG. 3B  is a cross-section of an horizontal conduit along a diameter of the conduit showing an embodiment sensor. 
           [0025]      FIG. 4  is the front of an embodiment alarm box. 
           [0026]      FIG. 5  is a cross-section of a flat roof building showing a primary drain and overflow drain with a second embodiment flow detection system. 
           [0027]      FIG. 6A  is a cross-section of an horizontal conduit taken along the conduit length showing a second embodiment sensor. 
           [0028]      FIG. 6B  is a cross-section of an horizontal conduit along a diameter of the conduit showing a second embodiment sensor. 
           [0029]      FIG. 7  is the front of a second embodiment alarm box. 
       
    
    
     DETAILED DESCRIPTION 
       [0030]      FIG. 1  is a cross-section of a flat roof building showing a primary drain and overflow drain with an embodiment flow detection system. The vertical wall  110 , flat roof  112 , and roof parapet  114  are depicted schematically. 
         [0031]    One or more primary drains  120  are set into the flat roof and provide the main drainage from the roof. Visible in  FIG. 1  are the drain bowl  124 , the primary drain conduit  122 , which carries the water to a primary drain discharge, in this case the building sewer system. Shown on the surface of the roof is the drain rim  125 , primary drain strainer  126  with primary drain strainer openings  127  which allowed the entry of water from the roof into the primary drain. 
         [0032]    One or more secondary or emergency or overflow drains  130  are also set into the flat roof and provide drainage after water accumulates on the roof beyond the capacity of the primary drains. Visible in  FIG. 1  are the drain bowl  134 , the secondary drain conduit  132 , which carries water from the secondary drain via a horizontal portion  133  of the conduit to the secondary drain discharge  139 , in this case an opening on the external wall  116 . Shown on the surface of the roof is the drain rim  135 , secondary drain strainer  131  with secondary drain strainer openings  138  which allowed the entry of water from the roof into the primary drain. Also shown in the secondary drain dam  136  which prevented the flow of water into the secondary drain until the level of water on the roof exceeded the height of the secondary drain dam  136 . 
         [0033]    A flow sensor  140  sensed the presence of flowing water in the horizontal conduit or pipe  133  of the secondary drain. The sensor mounts on top of the horizontal conduit  133  with a non-corrosive vane located in the conduit. The vane does not impede flow through the conduit. A signal from the flow sensor is sent via a connector  144  to the alarm box  142  which can be located in a central facility monitoring system. The sensor switch can be wired for either normally open or normally closed operation. The alarm box provides an audible and a visual signal of the presence of water flow in the secondary drain. The signal from the sensor is activated by a certain minimal amount of flow, in embodiments, 5 gallons per minute. The alarm box indicates the presence of a significant amount of flow in the secondary drain, and thus the seriousness of the drainage problem. 
         [0034]    In the face of extensive rain or melting ice and snow, water will accumulate on the area of the flat roof  112  between the parapet walls  114 . Excessive accumulation of water encourages leaks in the roof and, more importantly, challenges the structural integrity of the roof The water is drained by the generally multiple primary drains  120 . If the primary drain or drains is plugged by debris, or is simply overwhelmed by the rate of raining, the level of water on the roof rises over the height of the secondary drain dam  136 , and is drained through the secondary drain. Embodiments provide signals of the usage of the secondary drain and inform the building user of the need to monitor the condition of the primary drains and assure they are clear and adequately working. 
         [0035]      FIG. 2  is a cross-section of a flat roof building showing a primary drain and overflow drain which use a common drain conduit with an embodiment flow detection system. The vertical wall  110 , flat roof  112 , and roof parapet  114  are depicted schematically. 
         [0036]    One or more primary drains  120  are set into the flat roof and provide the main drainage from the roof Visible in  FIG. 2  are the drain bowl  124 , the primary drain conduit  122 , which carries the water to a primary drain discharge, in this case the building sewer system  128 . Shown on the surface of the roof is the drain rim  125 , primary drain strainer  126  with primary drain strainer openings  127  which allowed the entry of water from the roof into the primary drain. 
         [0037]    One or more secondary or emergency or overflow drains  130  are also set into the flat roof and provide drainage after water accumulates on the roof beyond the capacity of the primary drains. Visible in  FIG. 2  are the drain bowl  134 , the secondary drain conduit  132 , which carries water from the secondary drain via a horizontal portion  133  of the conduit In this configuration the secondary drain conduit is connected to and drains into the primary drain conduit  122  at a connection  137 . Shown on the surface of the roof is the drain rim  135 , secondary drain strainer  131  with secondary drain strainer openings  138  which allowed the entry of water from the roof into the primary drain. Also shown in the secondary drain dam  136  which prevented the flow of water into the secondary drain until the level of water on the roof exceeded the height of the secondary drain dam  136 . 
         [0038]    A flow sensor  140  sensed the presence of flowing water in the horizontal portion of the conduit  133  of the secondary drain. A signal from the flow sensor is sent via a connector  144  to the alarm box  142 . The alarm box provides an audible and a visual signal of the presence of water flow in the secondary drain. 
         [0039]      FIG. 3A  is a cross-section of an horizontal conduit taken along the conduit length showing an embodiment sensor. Visible in  FIG. 3A  is the conduit  133 , the sensor paddle  142 , which is connected by a pivot  141  to the flow sensor base  143 . Flow in the conduit in the direction indicated by arrow A causes movement of the paddle  142  which is detected by the sensor  140 . An electrical signal activated by the movement of the paddle  142  is transmitted from the sensor by a connector  144  to an alarm box (not shown in  FIG. 3A ). In embodiments, the electrical signal is activated when the flow rate exceeds 5 gallons per minute, and is inactivated when the flow drops below that rate. 
         [0040]      FIG. 3B  is a cross-section of an horizontal conduit taken along across a conduit diameter showing an embodiment sensor. Visible in  FIG. 3B  is the conduit  133 , the sensor paddle  142 , which is connected by a pivot  141  to the flow sensor base  143 . Flow in the conduit causes movement of the paddle  142  which is detected by the sensor  140 . An electrical signal activated by movement of the paddle  142  is transmitted from the sensor by a connector  144  to an alarm box (not shown in  FIG. 3B ). 
         [0041]      FIG. 4  is the front of an embodiment alarm box  150 . Visible in  FIG. 4  is a terminal  153  for connecting with the connector from the sensor. Also visible in  FIG. 4  is a silence button  155  for muting the audible alarm, a test button  156  for assessing the operation of the alarm box, a flow light  157  which is illuminated when the sensor indicates flow in the secondary conduit, a power on light  158  which is illuminated when the control box has power, and a power plug  159 . The operating characteristics are similar to operating a smoke alarm. In embodiments the alarm box is powered by a  9  volt batters. A low battery condition is indicated by a chirping sound. The flow sensor alarm box can be remotely located and, in some embodiments, is provided with internal auxiliary contacts for wiring into the building&#39;s central moniroring system or some other ancillary device. 
         [0042]      FIG. 5  is a cross-section of a flat roof building showing a primary drain and overflow drain with a second embodiment flow detection system. The elements of  FIG. 5  is identical to those of  FIG. 1  with the exception of the second embodiment flow detection system. In the second embodiment system the flow sensor  240  is not connected by a connector to the alarm box. Rather the second embodiment sensor  240  has a radio frequency transmitter  244  which emits a radio signal which is activated by the flow in the flow sensor. In the second embodiment system the alarm box  250  has a radio frequency receiver  254 . 
         [0043]      FIG. 6A  is a cross-section of an horizontal conduit taken along the conduit length showing a second embodiment sensor. The features in  FIG. 6A  are identical to those in  FIG. 3  A with the exception of the second embodiment flow detection system. In the second embodiment system the flow sensor  240  is not connected by a connector to the alarm box. Rather the second embodiment sensor  240  has a radio frequency transmitter  244  which emits a radio signal which is activated by flow in the flow sensor. 
         [0044]      FIG. 6B  is a cross-section of an horizontal conduit along a diameter of the conduit showing a second embodiment sensor. The features in  FIG. 6B  are identical to those in  FIG. 3  B with the exception of the second embodiment flow detection system. In the second embodiment system the flow sensor  240  is not connected by a connector to the alarm box. Rather the second embodiment sensor  240  has a radio frequency transmitter  244  which emits a radio signal which is activated by the flow in the flow sensor. 
         [0045]      FIG. 7  is the front of a second embodiment alarm box. The elements of  FIG. 7  are identical to  FIG. 4  with the exception of the second embodiment system. The second embodiment alarm box  250  has a radio frequency receiver  254  rather than a terminal. 
         [0046]    Embodiment conductors are made of any suitable strong, flexible, conductor wires or cables. The conductor may include provisions for providing electrical power from the alarm box to the sensor. Specifically contemplated are optical waveguide conductors. They would include an optical transmitter mounted on the sensor, an optical fiber, and a optical receiver mounted on the alarm box. 
         [0047]    Embodiment wireless transmitter and receivers are any suitable system. One example is model RLB-55 obtainable from Black Box Corporation, Lawrence Pa. 
         [0048]    Any suitable strong, impervious, corrosion resistant conduit can be used in embodiments. Embodiments include pipes of diameters from 3 inches to 12 inches. Embodiments include those conduits manufactured of iron, steel, copper, and polyvinyl chloride. 
         [0049]    While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and subcombinations thereof. It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope. The applicant or applicants have attempted to disclose all the embodiments of the invention that could be reasonably foreseen. There may be unforeseeable insubstantial modifications that remain as equivalents.