Fire extinguishers – Processes
Reexamination Certificate
2001-12-21
2002-12-10
Ganey, Steven J. (Department: 3752)
Fire extinguishers
Processes
C169S042000, C169S061000, C169SDIG003, C169S037000, C239S075000, C340S590000
Reexamination Certificate
active
06491110
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an electric thermal ampoule for a sprinkler.
DESCRIPTION OF THE RELATED TECHNOLOGY
Generally, sprinklers are fire fighting equipment installed on the ceilings of buildings for spraying extinguishing liquid, or water, upon sensing the occurrence of a fire, so as to extinguish the fire.
A typical sprinkler head H comprises, as shown in
FIG. 1
, an extinguishing liquid discharging nozzle
1
coupled with an extinguishing liquid supply pipe
33
via a pipe coupling socket
23
, an O-ring-shaped body
2
extending downwardly out of the outer surface of the discharging nozzle
1
, an extinguishing liquid diffusing plate
6
fitted horizontally under and to the lower end of the O-ring-shaped body
2
, a valve plate
3
for normally holding the discharging nozzle
1
closed, a trigger
4
installed within a space between the valve plate
3
and the bottom of the body
2
for supporting the valve plate
3
, and a thermal fuse
7
installed within the trigger
4
. The thermal fuse F includes, as shown in
FIG. 2
, a hollow drum-shaped casing
11
enclosed at its bottom, low-temperature fusing lead
13
filled within the casing
11
and held solid at room temperature, and an actuating pin
12
held within the lead
13
at its lower end and projected out of the top of the casing
11
at its upper end. As the ambient temperature rises due to the occurrence of a fire, the low-temperature fusing lead
13
in the thermal fuse
7
fuses to become a liquid state, thereby causing the actuating pin
12
to be sunk in the lead
13
and thus the valve plate supporting balance of the trigger
4
to be broken. As a result, the valve plate
3
opens the extinguishing liquid discharging nozzle
1
to spray extinguishing liquid.
There has been proposed another conventional sprinkler wherein a glass ampoule (not shown) filled with a temperature-expansive gas(G) is provided instead of the above low-temperature fusing lead-type thermal fuse as shown in FIG.
3
. If a fire occurs, then the gas in the glass ampoule expands to break the glass ampoule, thereby causing a valve plate supporting force to be lost. This sprinkler is substantially the same in operation as that with the low-temperature lead thermal fuse.
On the other hand, the above-mentioned conventional sprinklers using either the low-temperature lead fuse or temperature-expansive glass ampoule have such a structure that the fuse or glass ampoule reacts directly to substantial heat of a fire. In this regard, such conventional sprinklers are disadvantageous in that they have a very slow response to the initial stage of a fire because they are not actuated in the event of the fire until the ambient temperature reaches a fusing point of the low-temperature lead or an expansion-breaking point of the glass ampoule. In connection with such a problem, U.S. Pat. No. 2,245,144, invented by William B. Griffith, et al., shows a technique for breaking or melting the glass ampoule or low-temperature lead fuse using not the fire heat but electric heating means. In this U.S. patent, as shown in
FIG. 4
, in the event of a fire, a diaphragm (41 in the patent) first expands at a low temperature prior to the melting of the fuse and then applies electric power to an electric heating coil (20 in the patent) around the fuse or glass ampoule. In this technique, the diaphragm functions as a mechanical temperature sensor expanding when the ambient temperature exceeds a predetermined threshold value and also as an electrical switch for applying electric power to electric heating means(electric heating coil) upon the expansion.
Another approach to using the electric heating means around the fuse or glass ampoule is shown in International Application No. PCT/FI93/00164 (International Publication No. WO 93/21998), inverted by Sundholm, Gbran. In this publication, as shown in
FIGS. 5
a,
5
b
and
5
c,
an electric heating coil(
8
in the publication) of memory metal is laid around the glass ampoule. The memory metal coil is held contracted at room temperature to hold an electric circuit opened (see
FIG. 5
a
). When the ambient temperature reaches a predetermined threshold value due to the occurrence of a fire, the memory metal coil changes(or expands) its shape to function as a switch for closing the electric circuit. After closing the electric circuit, the memory metal coil functions as the electric heating means for heating the fuse or ampoule. For reference,
FIG. 5
b
shows a state where the memory metal coil expands and makes an electrical connection to act as a heater, and
FIG. 5
c
shows a state where a spindle (5 in the publication) is pressed downwardly (to spray extinguishing liquid) under the influence of a spring (6 in the publication) after the glass ampoule is broken.
The sprinklers shown in the '144 patent and '21998 publication comprise the electric heating means for heating the fuse or glass ampoule at a predetermined low temperature before the substantial fire heat reaches the fuse or glass ampoule. In this regard, such sprinklers are advantageous in that they have a faster response to the initial stage of a fire than that of the conventional sprinklers using the glass ampoule or fuse breaking or melting due to the direct heating by the substantial fire heat. However, such sprinklers still have the following disadvantages.
Firstly, because fire-fighting equipment, such as sprinklers, is installed and not used until the occurrence of a fire, it is unused for a lengthy period of time due to the fact that there is no fire. As a result, the fire fighting equipment may be aged or have partially damaged electric circuitry due to a lack of maintenance, finally becoming inoperable in the actual event of a fire. In order to solve this problem, there is a need to frequently test the normal operations of the sprinklers. However, it is not easy to frequently test a large number of sprinklers installed on the ceiling.
Secondly, in almost all cases, a fire starts in a localized area, and only a sprinkler installed in that local area is actuated. Sprinklers installed in other adjacent rooms are not actuated, thereby making it impossible to prevent the fire from spreading to the adjacent rooms. On the other hand, in the previously stated '144 patent, another switching means (37 in the patent) is provided in addition to the diaphragm-type mechanical/ electrical switching means to manually close the electric circuit. The provision of such other switching means may establish manual electrical connections to sprinklers in other places than the place where a fire stars, as needed. However, this '144 patent does not show any means (for example, means for connection between sprinklers, means for acquiring information needed for an operator's operation, command transfer means, etc.) embodied for controlling individual electrical connections to the respective sprinklers.
In consideration of the forgoing problems in conventional sprinklers, the present inventor suggested in Korean patent application No. 2000-8114 (corresponding PCT/KR00/00186) filed on Feb. 21, 2000, as shown in
FIGS. 6
to
10
, a sprinkler apparatus comprising a heater
14
operable by temperature sensing means, a thermal fuse
13
melting by heat from said heater, and a valve plate
3
for opening an extinguishing liquid discharging nozzle of a sprinkler head in response to the melting of said thermal fuse to discharge extinguishing liquid, wherein said sprinkler apparatus further comprises a sprinkler head controller C including a transmitter and a receiver, said sprinkler head controller performing a self-diagnostic operation according to an algorithm contained therein in such a manner that it supplies a small amount of current to said heater and detects the amount of current flowing through said heater and externally transmitting the self-diagnostic result and a temperature value sensed by said temperature sensing means; and a main computer MC installed in a central control station for informing an operator of said self-diagnostic r
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