Automatic sprinkler of fire detector type and sprinkler...

Details Automatic sprinkler of fire detector type and sprinkler... Automatic sprinkler of fire detector type and sprinkler...

2000-09-01

2003-09-09

Douglas, Lisa A. (Department: 3752)

Fire extinguishers

Sprinkler heads

C169S042000

Reexamination Certificate

active

06615927

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is related to an automatic sprinkler of fire detector type and sprinkler system including the automatic sprinkler of fire detector type.
In particular, this invention is related to an automatic sprinkler of fire detector type that has not only its inherent function to make opening by itself when a fire occurs, but also a function of electric switch similar to an ordinary fixed-temperature fire detector, and the sprinkler system that includes the automatic sprinkler of fire detector type. More particularly, the above sprinkler system can detect a fire in a freely established area with one or more sprinklers where sprinkler opens.
2. Description of the Prior Art
In general, two types are found in sprinklers; one is closed-type sprinkler and the other is open-type sprinkler.
The closed-type sprinkler includes a heat-actuated element in itself that normally seals a water discharge orifice and is separated by itself from the sprinkler by heat from a fire, and so the closed-type sprinkler is called ‘automatic sprinkler’ in most literatures of fire protection.
There are various kinds of existing automatic sprinkler, but two operating modes may be found in all automatic sprinklers; one sprinkler can not re-close by itself once opened by heat, but the other sprinkler to be usually called ‘on-off sprinkler’ can automatically repeat opening and closing in turn by a rise or drop in ambient temperature in the course of fire control.
The automatic sprinkler of non-reclosable type has a heat-actuated element to be fusible or frangible by heat. The fusible heat-actuated element that holds a small quantity of metal to be fusible at a predetermined temperature normally seals a water discharge orifice of sprinkler and then the water discharge orifice is opened when the fusible heat-actuated element is separated from the sprinkler due to melting of the metal by heat. The frangible heat-actuated element that holds a glass bulb containing some liquid of good thermal expansion property normally seals a water discharge orifice of sprinkler and then the water discharge orifice is immediately opened when the bulb is broken by the expanding pressure of liquid generated in the bulb at a predetermined temperature. Typical on-off sprinkler usually has two thermal elements; one is a frangible bulb to initially open the sprinkler orifice and the other is a pilot valve leading to the repeat of opening and closing of a water discharge outlet according to actuation of bimetallic disc by a rise or drop in ambient temperature in the course of fire control. The opening of pilot valve allows water to flow from the sprinkler. When the sprinkler discharge suppresses the fire so the temperature of bimetallic disc drops, the pilot valve is closed and then the waterflow stops.
FIG. 1
shows an outlined drawing of an exemplification of existing automatic sprinkler. And
FIG. 2
is a drawing to show that the sprinkler in
FIG. 1
opens with separation of fusible heat-actuated element. Such a sort of sprinkler(
11
), which has been used for a long time, is composed of three essential parts, one of which is a heat-actuated element(
17
) to be fusible that normally seals a water discharge orifice(
13
), another is a metallic framed-body(
12
) with a water discharge orifice(
13
) and the other is a deflector(
15
) for dispersion of water discharged out of the water discharge orifice(
13
) on the other side of water discharge orifice(
13
). The fusible heat-actuated element(
17
) tightly seals the water discharge orifice(
13
) by driving a screw(
16
) in the center of deflector(
15
). The fusible heat-actuated element(
17
) is shaped by assembling several components, one of which is the fusible metal to be previously mentioned, not shown in the drawing, is included. The separation of fusible heat-actuated element(
17
) from the sprinkler is occurred simultaneously with disassembly of the fusible heat-actuated element(
17
) since mechanical balance built up among the components of fusible heat-actuated element(
17
) is lost when the fusible metal held in the fusible heat-actuated element(
17
) is melted by heat. And the automatic sprinkler of framed-body type is the most commonly used in many countries in the world. The metallic framed-body may have two or more frames(
14
). An orifice-sealing disc(
18
) and a disc-supporting metal(
19
) of round type can be positioned between the water discharge orifice(
13
) and the fusible heat-actuated element(
17
).
However, any of all existing automatic sprinklers does not have a mechanism in itself to directly actuate electric circuit that may be introduced for supervisions of sprinkler system such as fire detection, fire indication and fire alert, etc. as shown in ordinary fire detection systems, and so supplemental fire detection system or means for detecting a waterflow to be initiated by discharge of water or air (or nitrogen) from opened sprinkler has been utilized over years for detection of a fire in sprinklered area.
The wet pipe sprinkler system in
FIG. 3
, the dry pipe sprinkler system in FIG.
4
and the preaction sprinkler system in
FIG. 5
are the most typically and widely used among the various existing automatic sprinkler systems.
In the automatic sprinkler systems, one or more water supplies, system pipings and automatic sprinklers are the essential requirements, however, there are various differences between them in system design feature and functional aspect. And, fire water may be obtained from a public or private water source, and in a water supply with a private source, water tank or pond is usually required while associated with fire pump. Such a water tank connected to fire pump as shown in the drawings is primarily necessitated, but an auxiliary tank such as an elevated tank may be included as a supplementary water source. There are various design features in configuration of water supply for sprinkler system, being influenced by infrastructures and circumstances given to a sprinklered building or structure, however, a primary water tank associated with a fire pump and a pressure maintenance pump, and a supplementary elevated tank(
23
) are examplified for water supply to the sprinkler systems shown in
FIGS. 3
,
4
and
5
. The pressure maintenance pump is employed to make up water pressure in system pipings since a pressure drop in the system pipings to be initiated by water discharge from opened sprinkler can be utilized for automatic operation of the fire pump. In this case, pressure switches are usually used to detect the pressure drop or rise for starting or stopping the fire pump and the pressure maintenance pump.
In such the wet pipe sprinkler system as shown in
FIG. 3
, all pipings(
21
) always contain water and are connected to water supply so that water discharges immediately from the sprinklers(
11
) opened by heat from a fire. The wet pipe sprinkler system is the simplest and the most reliable of all the sprinkler systems, but it is undesirable to employ this system in the sprinklered area to be subject to water freezing.
In the wet pipe sprinkler system, a waterflow detecting device(
31
) to be called ‘alarm check valve’ is the most commonly employed on a system riser pipe(
54
) to detect opening of sprinkler(
11
), that is, the opening of sprinkler lets water discharge into the fire area and in turn the water flowing to the opened area through the system riser pipe activate the waterflow detecting device(
31
).
And, a test-connection(
26
) examplified in
FIGS. 3 and 4
is usually installed to routinely test the performance of waterflow detecting device.
As shown in
FIG. 4
, the dry pipe sprinkler system developed to meet the need for sprinkler protection in unheated occupancies or structures has a dry pipe valve(
25
) on a system riser pipe(
54
), and all system pipings(
21
) above the dry pipe valve(
25
) do not contain water but air or nitrogen under pressure. The air or nitrogen pressure restrains the water in the water supply main at the clapper arrangement (not s

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