Fire extinguishers – Special applications – Condition responsive control
Reexamination Certificate
1999-01-25
2001-11-20
Scherbel, David A. (Department: 3752)
Fire extinguishers
Special applications
Condition responsive control
C169S019000, C169S054000
Reexamination Certificate
active
06318475
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of air scrubbers, and, more particularly, to a fire extinguishing system for a centralized gas and vapor collection system.
BACKGROUND OF THE INVENTION
In laboratories and industrial plants where smoke and fumes may be produced during certain steps of a fabrication process, it is necessary to filter noxious gases and fumes from the air to prevent atmospheric pollution. Such an operation is carried out by specifically designed scrubbing systems, also referred to as scrubbers. Scrubbers purify the gases collected at the various locations where smoke, fumes or other polluting gaseous substances are released. Due to the large investment needed for obtaining efficient scrubbing systems, it is a common practice to select a centralized scrubbing system where suction ducts convey the gas-air mixture. This is particularly applicable when there are numerous locations releasing substances in need of being filtered, as depicted in
FIGS. 1
a
and
1
b.
Collection systems include suction ducts that interconnect different suction locations through a branch-like or star-like conduit structure, as shown in
FIGS. 1
a
,
1
b
and
2
. Similar suction systems for recirculation are also present in centralized air-conditioning installations to draw the air from the rooms and provide it to a purification and conditioning station. The suction ducts are often installed on the roofs of buildings, and consequently, they are exposed to intense solar irradiation and other atmospheric agents that may damage the suction ducts through prolonged exposure. It is common practice to use fiber glass reinforced resin pipes or similar corrosion and heat resistant materials capable of resisting attack from chemical substances that may eventually be released in the gaseous mixture conveyed through the suction ducts.
If a fire develops in an air suction area, the flames may reach other suction areas through the collecting conduits that join at the nearest node of the suction system. Furthermore, spreading of the fire may even be aided by the automatic switching off of the suction system. This feature is commonly implemented at scrubbing plants to meet safety rules in case of a fire.
SUMMARY OF THE INVENTION
The present invention provides an effective device for preventing a fire from spreading through suction ducts that convey smoke, fumes or other gaseous mixtures generated in certain working areas. The flame and fume stopping device of the invention is simple to implement and is reliable and effective in its operation.
According to the invention, an effective flame and fume stopping device for a suction duct that conveys gaseous mixtures from a working area or room comprises a normally empty goose neck portion installed along the suction duct. The goose neck portion is installed as close as possible to the suction inlet. A water tank large enough to hold a volume of water sufficient to flood the goose neck is also provided. The water tank is positioned at a level higher than the goose neck portion of the suction duct and has a gravity discharge pipe operated by a solenoid valve. A solenoid valve is used for releasing the water into the siphon. A heat detector triggers an electric command for the solenoid valve when the temperature of the gaseous mixture exceeds a certain threshold.
The device of the invention operates like a fuse by blocking the suction conduit to stop spreading of the fire therethrough. A fuse-like flame and fume stopping device of the invention may be installed along each suction duct in any room. Installation is preferably as close as possible to the suction inlet where smoke and fumes are likely to originate.
Activation of the device by an isolated fire prevents spreading of the smoke and flames through the suction duct, even when the centralized system continues to operate. However, operation of the flame and fume stopping device is bidirectional. That is, operation of the flame and fume stopping device is ensured whether the fire originates at the inlet point of the suction duct, or if the fire is reaching the device through the suction duct from the centralized scrubbing station.
REFERENCES:
patent: 2382120 (1945-08-01), White
patent: 2571961 (1951-10-01), Smith
patent: 2988150 (1961-06-01), Smith
patent: 3488170 (1970-01-01), Smith
patent: 3592207 (1971-07-01), Borello
patent: 3645337 (1972-02-01), Livingston
patent: 4143670 (1979-03-01), Olson et al.
patent: 4519458 (1985-05-01), Kroeter
patent: 4545528 (1985-10-01), Perez
patent: 4984637 (1991-01-01), Finnigan
patent: 173185 (1933-12-01), None
patent: 41 26 932 A1 (1993-02-01), None
patent: 0 559 968 A1 (1992-12-01), None
patent: 0 353 840 A1 (1989-05-01), None
patent: 556-818 (1977-09-01), None
Allen Dyer Doppelt Milbrath & Gilchrist, P.A.
Galanthay Theodore E.
Kim Christopher S.
Scherbel David A.
STMicroelectronics S.r.l.
LandOfFree
Flames and fumes stopping device for suction ducts does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Flames and fumes stopping device for suction ducts, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Flames and fumes stopping device for suction ducts will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2615343