This invention relates to a device for protecting frangible items, and especially to frangible glass bulbs used in sprinkler heads of fire suppression systems.
Fire suppression systems are used extensively in office buildings, warehouses, factories, hotels, homes and other buildings and structures to provide a reliable and effective means to suppress the spread of fire throughout the building or structure. Such systems may comprise a piping network extending throughout the building. The piping network is connected to a source of fire suppressing fluid, for example, water, and is in fluid communication with sprinkler heads distributed throughout the building which will discharge the fire suppressing fluid in the event of a fire.
Each sprinkler head has a valve which is biased into a normally open position, but is held in a closed position against the biasing force by a frangible glass bulb that contains a heat-sensitive fluid. The bulb is elongate in design and the biasing force places it under compression along its long axis. The bulb is very strong in compression along its long axis but easily breaks when force is applied transverse to this axis. During a fire, the heat-sensitive fluid expands within the bulb and when a predetermined temperature is reached the heat-sensitive fluid applies hydraulic pressure outwardly against the bulb normal to the long axis, causing the bulb to shatter, and thereby allow the valve to open and discharge the fire suppressing fluid.
The bulb is designed to break at the predetermined temperature, and when installed properly is very reliable. However, the bulb must be frangible to operate effectively and is typically made of glass which is susceptible to damage. Damage which can compromise the performance of the bulb may be caused during packing, shipping or installation of the sprinkler head and may comprise a scratch or nick in the bulb caused by a tool or another sprinkler head, as well as a crack or a small hole which allows the heat-sensitive fluid to escape. If such damage is not prevented or at least mitigated, then it is possible that the bulb may fail prematurely at a temperature lower than the predetermined temperature, thus, triggering discharge from the sprinkler head in the absence of a fire condition. This may result in extensive water damage to the building and its contents. More seriously, the damage may prevent the sprinkler head from discharging at all, as may happen if the heat-sensitive fluid is permitted to leak out. This condition will compromise the fire safety of the building and should be avoided. It is, therefore, desirable to protect such frangible items during handling, packing, shipping and installation of the sprinkler heads to ensure that they function properly when the fire suppression system is brought on line.
The invention concerns a cover for protecting a frangible item mounted within a support frame such as a glass bulb used with a sprinkler head in a fire suppression system. The cover comprises a first cover portion positionable adjacent to the frangible item and having a first end. A second cover portion is also positionable adjacent to the frangible item but opposite to the first cover portion. The second cover portion has a second end, the first and second ends of the cover portions being attached to one another. A first finger projects from the first cover portion toward the second cover portion and is positioned in spaced relation to the first and second ends. A first space is defined between the first finger and the first and second ends for receiving a portion of the support frame, the first finger and the first and second ends of the cover portions engage the support frame for positioning the cover thereon adjacent to the frangible item.
The cover may also comprise a first opposite end positioned on the first cover portion opposite the first end and a second opposite end positioned on the second cover portion opposite the second end. A second finger projects from one of the first and second cover portions toward the other of the first and second cover portions. The second finger is positioned in spaced relation to the first and second opposite ends. A second space is defined between the second finger and the first and second opposite ends for receiving another portion of the support frame. The second finger and the first and second opposite ends of the cover portions engage the support frame for positioning the cover thereon adjacent to the frangible item.
Another embodiment of a cover for protecting a frangible item mounted within a support frame comprises a pair of interengageable cover portions positionable on opposite sides of the frangible item. Each of the cover portions comprises a first end having a latch extending therefrom, a second end having a slot therein and a first finger positioned in spaced relation to one of the first and the second ends. The first finger extends in substantially the same direction as the latch. The cover portions are positionable in engagement one with another by aligning the cover portions and inserting the latches on each one of the cover portions into the slots on each other of the cover portions. A first and a second space are defined between the first fingers and the first and second ends of the cover portions upon their engagement. Each of the spaces receives a respective portion of the support frame. The first fingers and the ends of the cover portions engage the portions of the support frame for positioning the cover thereon adjacent to the frangible item.
A cover 28, shown in solid line, is removably mounted on the support frame 12 surrounding and protecting the glass bulb 26 exposed in the open space 20 between limbs 16 and 18. As shown in
A fastener 36 may be positioned between the respective ends 35a and 35b of cover portions 30 and 32 opposite the hinge 34. Fastener 36 releasably attaches ends 35a and 35b to one another, and preferably comprises a latch 38 extending from one cover portion (in this example cover portion 30) and a slot 40 in the other cover portion (32) sized and aligned to receive the latch 38. Latch 38 is cantilevered from the cover portion 30 and has a barbed end 42 which engages the slot 40 and prevents inadvertent removal of the latch 38 from the slot 40. However, latch 38 is flexible and resilient and may be manually deformed so that the barbed end 42 disengages from slot 40 to allow the cover portions 30 and 32 to be pivoted about hinge 34 into the open position shown in solid line in
As shown in
As shown in
Preferably, space 58 is substantially aligned with space 48, space 60 is substantially aligned with space 50 and space 62 is substantially aligned with space 52. The fingers may have different lengths to accommodate any variation in dimensions of the limbs 16 and 18.
Preferably, as shown in
Preferably, cover portion 72 is a mirror image of cover portion 70, each having a latch 38 at one end, a slot 40 at an opposite end, and a finger identified as 80a or 80b, which extends toward the opposite cover portion when the cover 68 is mounted on the support frame 12. Such a configuration allows each cover portion 70 and 72 to be substantially identical to one another, thus saving on capital costs, such as molds, associated with manufacture.
As best shown in
As shown in
Preferably, space 90 is substantially aligned with space 82, space 92 is substantially aligned with space 84 and space 94 is substantially aligned with space 86. The fingers may have different lengths to accommodate any variation in dimensions of the limbs 16 and 18.
Again, as best shown in
Covers according to the invention are preferably made of polymers such as polypropylene, polyethylene, and nylon in an injection molding process. These plastics are preferred because they result in a tough, resilient cover which maintains its flexibility and structural integrity over a wide temperature range.
Use of covers as described herein will provide increased protection to frangible bulbs used in sprinkler heads thus providing a greater degree of fire safety by increasing the likelihood that properly functioning sprinkler heads are installed in fire suppression systems. The covers will also help reduce costs as fewer bulbs will be damaged during handling, packing, shipping and installation and require replacement.
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Number | Date | Country | |
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20050035022 A1 | Feb 2005 | US |