Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2000-01-27
2001-05-01
Trieu, Van T. (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S602000, C340S605000, C073S335020
Reexamination Certificate
active
06225909
ABSTRACT:
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 '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
Galgano & Burke
Trieu Van T.
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