Abstract:
A roof vent for use in a flat roof having a plurality of layers of roofing material including a waterproof membrane which includes a base flange dimensioned to fit in between two of the plurality of layers of roofing material, an upstanding hollow member coupled to the base flange, an electrical connector mounted mounted on said hollow member, and at least one moisture sensing element electrically coupled to the electrical connector and deployable on one of the plurality of layers of roofing material, wherein the moisture sensing element is in the form of a strip which is deployed like tape. All of the sensing elements are coupled via the electrial connectors of the vents to a central controller which has a display and a modem for signaling an alphanumeric pager of a leak condition.

Description:
This application is a continuation-in-part of application Ser. No. 09/081,177 filed May 9, 1998, now U.S. Pat. No. 6,040,775. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a roof vent for a flat roof. More particularly, the invention relates to a roof vent with a moisture detector for the early detection of a roof leak and to a roof system incorporating several such vents. 
     2. State of the Art 
     Commercial, industrial, and institutional flat roof systems generally include several layers of material, i.e. a deck covered with lightweight insulating concrete, a vapor barrier covering the concrete, roofing material covering the vapor barrier, a moisture barrier membrane covering the roofing material, and a top layer of gravel, tar, ballast, etc. These watertight roof systems are generally effective at preventing water from passing through the roof system into the building. However, these systems can and do leak due to damage, material failure, or poor workmanship. When these types of roof systems leak, moisture tends to become trapped between the layers of the system where it remains undetected until substantial damage is done. 
     In order to prevent moisture from being trapped between the layers of a roof system, it is common to provide vents spaced throughout the roof system. FIG. 1 shows a prior art roof vent and FIG. 2 shows the vent installed in a conventional prior art roof system. The known vent  10  generally includes a circular base flange  12 , an upstanding hollow frustroconical body  14  terminating with a cap  15 , the cap and the body defining an annular opening into the body  14 . The vent  10  is installed in a conventional roofing system  17  which includes a deck  18 , insulating concrete  26 , a vapor barrier  23 , and an upper membrane  22 . The vent  10  is located such that the flange  12  is on top of the waterproof membrane  22  and is covered with flashing  24 . The membrane  22  and the flashing  24  are covered with gravel, tar, ballast, etc.  25 . 
     My prior U.S. Pat. No. 5,193,390, the complete disclosure of which is hereby incorporated herein by reference, discloses a modified roof vent and roof system which includes moisture detectors and moisture indicators. Prior art FIGS. 3-6 show the roof vents and roof system of the &#39;390 patent. The roof vent  30  generally includes a circular base flange  34  with an upstanding hollow frustroconical body  32 . The body  32  terminates with a cap  36  which is held in place by clamps  38  and which has a removable cover  36   a . The cap  36  is provided with a shoulder  39  having openings  42  which provide a vapor passage to the interior of the body  32  via a hole  44  in a lower platform  46  of the cap  36 . Preferably, a one-way diaphragm  45  is provided below the hole  44  which permits moisture to exit the body  32  but prevents moisture from entering. The cap  36  and the body  32  are sealed by mutually engaging ridges  48 ,  52 . 
     As seen in prior art FIG. 3, the cap  36  has three interior platforms: lower platform  46 , intermediate platform  54 , and upper platform  58 . The intermediate platform  54  includes a moisture indicator device or circuit  56  and the upper platform  58  includes a display  62  for indicating moisture such as a movable needle  64  which is coupled via an opening  66  to the device  56 . The circuit or device  56  is electrically coupled to at least one moisture sensing element  68  by insulated conductors  72 ,  74 . Moisture sensing elements of the type described in U.S. Pat. Nos. 4,110,945; 4,598,273; or 4,723,109 may be used and these prior U.S. patents are therefore incorporated herein by reference for their teaching of moisture sensors. 
     The vent  30  is installed in a roof system  63  as shown in prior art FIG.  4 . The roof system  63  generally includes a deck  18 ′ which is covered with a vapor barrier  23 ′ which is covered with insulation  26 ′ which is covered with a waterproof membrane  22 ′. The vent  30  is located with its flange  34  on top of the membrane  22 ′ and an opening is made in the insulation  26 ′ beneath the body  32  so that the moisture sensing element  68  may be placed directly upon the vapor barrier  23 ′. Preferably, a second moisture sensing element  76  is located between the insulation  26 ′ and the waterproof membrane  22 ′. Both sensing elements are coupled in parallel to the indicator circuit  56 . 
     The vent and roof system of my prior patent are effective in providing an early warning of roof leakage and in indicating where in a roof system a leak exists. According to the embodiment described (and illustrated in FIGS.  3  and  4 ), a periodic visual inspection is made of a roof where the cover  36   a  of each vent cap  36  is removed and the moisture indicator is inspected to determine whether the moisture sensing elements associated with the vent  30  are detecting moisture. A more sophisticated embodiment of my earlier invention is shown in prior art FIGS. 5 and 6. There each vent  80  is provided with a radio transmitter  82  and a radio receiver  84  is provided. According to this embodiment, each transmitter  82  transmits a unique signal when moisture is detected so that the receiver  84  will indicate not only that the roof  63  is leaking, but will indicate the approximate location of the leak. 
     The vent and roof system of my earlier patent work very well to achieve the objects for which they were designed. It is my intention to improve my earlier invention by making it more economical so that it may be utilized in a wider range of applications. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide a roof vent with a moisture detector and roof systems incorporating such vents. 
     It is also an object of the invention to provide a roof vent with a moisture detector which is relatively inexpensive, easy to install, and easy to operate. 
     In accord with these objects which will be discussed in detail below, first and second embodiments of the roof vents of the present invention include at least one moisture sensing element which is electrically coupled to an electrical connector in the roof vent. The electrical connector is located in the roof vent in such a manner that it is protected from the environment. A portable moisture sensing circuit or device with a moisture display for indicating a degree of moisture is provided with an electrical connector which mate with the electrical connector in the roof vent. According to the invention, the roof vents are installed in a roof system in much the same manner as described in my earlier patent. When it is time to inspect the roof, a worker carries the portable device from one roof vent to another and plugs the device connector into the vent connector to take a moisture reading from the sensing element(s) associated with each vent. Thus, the procedure for inspecting the roof involves substantially the same time and effort as the first embodiment of my earlier invention, but it has a significant economic advantage. Since only one electrical circuit and display is used, the total cost of a system having many roof vents is significantly less than the systems according to my prior patent. Preferred aspects of the first and second embodiments of the invention include: locating the electrical connector on the vent so that it is easily and rapidly accessed but protected from the environment, associating a plurality of moisture sensing elements with a single vent, and arranging the plurality of moisture sensing elements in a star or grid pattern. 
     According to a third embodiment of the invention, sensing elements from a plurality of roof vents are hard wired to a controller which constantly monitors the state of the sensing elements. The controller is preferably provided with a display and a modem so that the location of a leak can be displayed on the display and relayed to an alphanumeric pager. A preferred aspect of this embodiment is that the sensing elements are in the form of long strips. Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a prior art roof vent; 
     FIG. 2 is a sectional view of the vent of FIG. 1 installed in a prior art roof system; 
     FIG. 3 is an exploded perspective sectional view of a roof vent according to my prior U.S. Pat. No. 5,193,390; 
     FIG. 4 is a view similar to FIG. 2 showing a roof vent and roof system according to my prior U.S. Pat. No. 5,193,390; 
     FIGS. 5 and 6 are broken schematic views of a second embodiment of a roof vent and roof system according to my prior U.S. Pat. No. 5,193,390; 
     FIG. 7 is a schematic view of a roof vent and roof system according to a first embodiment of the present invention; 
     FIG. 8 is a schematic view of a roof vent according to a second embodiment of the present invention; 
     FIG. 9 is a broken perspective view of a portion of the vent of FIG. 8; 
     FIG. 10A is a schematic view of the electrical connector of the vent of FIG. 8; 
     FIG. 10B is a schematic view of an alternate embodiment of the electrical connector of the vent of FIG. 8; 
     FIG. 11 is a perspective schematic view of a portable moisture detector/display according to the second embodiment of the invention; 
     FIG. 12 is a broken schematic perspective view of a third embodiment of the invention; 
     FIG. 13 is a simplified schematic diagram of the third embodiment; and 
     FIG. 14 is a schematic view of a roof vent according to the invention with sensing elements in the form of strips. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to FIG. 7, a roof vent  100  according to a first embodiment of the invention includes a circular flange  102  with an upstanding cylindrical body  104  and a vent cap  106 . The cap  106  is joined to the upper end  104   a  of the body  104  so as to provide an annular opening (not shown) into the interior of the body  104 . In particular, according to this embodiment, the upper portion  104   a  of the body has a reduced diameter and the cap  106  has a diameter similar to the diameter of the lower portion of the body  104 . A female electrical connector  108  is carried on a sidewall of the cap  106  and is coupled by insulated cables  110 ,  112  to a pair of moisture sensing elements  114 ,  116 . According to the invention, a portable moisture sensing circuit/display  118  is provided with a male electrical connector  120  coupled to it by a cable  122 . The connector  120  is designed to electrically mate with the connector  108 . When the connectors are so mated, the moisture display  118  will indicate the amount of moisture sensed by the sensing elements  114 ,  116 . 
     As shown in FIG. 7, the roof vent  100  is installed in a roof system  150  having several layers. In particular, the roof system  150  has a concrete deck  152  which is covered with a layer of tar  154 , an insulation board  156 , a layer of EPDM rubber  158 , and a top layer of gravel, tar, or ballast, etc.  160 . According to the invention, an opening  156   a  is made in the insulation board  156  and an opening  158   a  in the EPDM rubber layer  158  so that the sensing elements  114 ,  116  may be placed between the tar layer  154  and the insulation board  156  with their electrical cables  110 ,  116  extending through the openings  156   a ,  158   a . A cylinder  162  made of STYROFOAM® or other insulating material is optimally placed in the openings  156   a ,  158   a  to minimize moisture condensation inside the roof vent  100 . The flange  102  of the vent  100  is placed on top of the EPDM rubber layer  158  under the top layer of gravel, tar, or ballast, etc.  160 . 
     Turning now to FIGS. 8-11, a second embodiment of a roof vent  200  of the invention includes a circular flange  202  with an upstanding tapered cylindrical body  204  terminating in a vent cap  206 . The cap  206  is joined to the upper end of the body  204  so as to provide an annular opening ( 207  in FIG. 9) into the interior of the body  204 . An electrical connector assembly  208  is carried on the sidewall of the body  204  and is coupled by insulated cables  210 ,  212   a-e  to five moisture sensing elements  214   a-e  which are arranged in a star pattern (or optionally a grid pattern) relative to the body  204 . According to this embodiment of the invention, a baffle  205  is provided inside the body  204  and is optionally equipped with a diaphragm (not shown) which prevents moisture from passing into the body  204  but allows moisture to vent out from the body  204 . As seen best in FIG. 10, the connector assembly  208  includes a female connector  208   a  which is mounted behind a cover  208   b  having hinges  208   c . The cover  208   b  protects the connector  208   a  from the environment and the hinges  208   c  allow easy access to the connector  208   a . Of course, other types of covers (e.g., screw-on) could be used. 
     According to the invention, and as shown in FIG. 11, a portable moisture sensing circuit/display  218  is provided with a male electrical connector  220  coupled to it by a cable  222 . The connector  220  is designed to electrically mate with the connector  208   a . When the connectors are so mated, the moisture display  218  will indicate the amount of moisture sensed by the sensing elements  214   a-e.    
     The roof vent  200  is mounted in a roof system in substantially the same manner as the vent  100  described above. The sensor elements  214   a-   214   e  are preferably arranged in a star pattern as shown. Depending on the nature of the roof system, more or fewer sensor elements may be used and the distance of each sensor element from the vent body may vary according to the nature of the roof system. 
     Turning now to FIGS. 12 and 13, according to a third embodiment of the invention, the sensing elements  311  are hard wired via the plurality of roof vents  200   a - 200   h  to a controller  230  via cables  211   a-   211   h  coupled respectively to each of the electrical connectors of the roof vents  200   a - 200   h . The controller  230  either mounted on the roof or in a remote location in the building is preferably coupled to a display  232  and a modem  234 . The controller  230  constantly monitors the status of the sensing elements and displays the status on the display  232 . If moisture is detected, the display  232  is updated to indicate where moisture was detected and controller activates the modem  234  whereby the status information is, e.g., relayed to an alphanumeric pager  236  via a pager or beeper service monitoring station to alert the roof maintenance staff of a roof leakage problem. 
     A presently preferred embodiment of a roof vent  300  is illustrated in FIG.  14 . The roof vent  300  includes a circular flange  302  with an upstanding tapered cylindrical body  304  terminating in a vent cap  306 . The cap  306  is joined to the upper end of the body  304  so as to provide an annular opening into the interior of the body  304 . An electrical connector assembly  308  is carried on the sidewall of the body  304  and is coupled by insulated cables  310  to four moisture sensing elements  314   a-d  which are arranges in a plus pattern relative to the body  304 . Alternatively, the sensor elements could be connected in a row-and-column grid-like pattern or in other configurations, if so desired. A baffle  305  is provided inside the body  304  and is equipped with a diaphragm (not shown) which prevents moisture from passing into the body  304  but allows moisture to vent out from the body  304 . According to this embodiment of the invention, each sensing element  314   a - 314   d  is a long strip which is laid out on the roof like tape in any desired length and/or arrangement. The insulated cables  310  are each individually connected to each sensing element and, in turn, are connected to the electrical connector  308  which has a plurality of electrical connectors, one coupled to each sensing element  314 ( a )-( e ). In this way, it can easily be determined which sensor has detected a leak. 
     There have been described and illustrated herein several embodiments of a roof vent having moisture detectors and roof systems incorporating the same. While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. Thus, while particular roof vents and electrical connectors have been disclosed, it will be appreciated that other types of roof vents and electrical connectors could be utilized. For example, while the generally upright roof vents are shown having a frustoconical configuration, they could be of any desired shape and size, such as boxed-shaped or a goose-neck-type shape (i.e., an inverted J-like profile). Also, while particular locations for the connectors on the vent have been shown, it will be recognized that other locations could be used with similar results obtained provided that the connector is protected from the environment and is easily accessible. Moreover, while particular configurations have been disclosed in reference to multiple sensor elements in a single vent with a single electrical connector, it will be appreciated that other configurations could be used as well. In particular it will be appreciated that where multiple sensor elements are deployed in conjunction with a single vent, multiple electrical connectors may be provided so that each sensor element may be read separately. 
     Furthermore, although the present invention is intended for use with flat roofs, it can also be used with sloped roofs. In addition, while the invention is intended to detect moisture in roof systems, it can be adapted to detect moisture in attics or in modular or mobile homes. Also, while the controller (e.g., a computer) has been shown having a display and a modem, it may also include input devices such as a keyboard and mouse in order to program the controller with regard to the modem and the display etc. It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its spirit and scope as so claimed.