Patent Application
20070007020
1. Field of the Invention
This invention pertains to apparatus for suppressing fires. More particularly, this invention pertains to an apparatus for actuating a fire suppression system.
2. Description of the Prior Art
Fire suppression systems are used in a wide variety of applications. A common fire suppression system will include a fire suppressant and an actuator for activating delivery of the fire suppressant to a site. For example, the fire suppressant may be contained within a pressurized container. The activation mechanism may include an activation head in the form of a valve coupled to the container for release of the fire suppressant upon actuation of the valve. The fire suppressant is delivered through tubing or the like to a nozzle, which is directed at a potential fire location. Fire suppression systems may be provided in buildings, transportation equipment such as vehicles, vessels or other installations where fire is a threat.
Not uncommonly, fire suppression systems may include automatic activation systems in the event of a detected fire. For example, buildings are commonly provided with nozzles having a mechanical thermal sensor, which degrades in response to heat. Such sensors may be a eutectic metal or thermal bulb technology, which degrades (such as melting or breaking) upon being exposed to a set temperature. In the event of such degradation of the element, the fire suppressant may be released through a nozzle.
Remote mechanical thermal detectors are also known in the prior art. An example of a mechanical thermal detector utilizes a mechanical thermal sensor coupled to the actuation head of a suppressant container by a cable under tension. In response to an elevated temperature, a mechanical thermal sensor may break or melt resulting in loss of tension on the cable. The loss of tension is detected at a control box. A control box houses a spring and a ratchet device to supply tension in the cable and the mechanical thermal sensor is located remote from the spring and ratchet assembly and in-line with the tension cable. The use of a tensioned cable limits the flexibility of installation and requires additional hardware, such as pulleys and brackets, to maintain tension in the cable over the life of the system. An example of such a prior art system is described in “Kidde WHDR™ Wet Chemical Fire Suppression System, Addendum No. 6 to Installation, Operation and Maintenance Manual, Part No. 87-12200-001, UL EX 3559, Design and Installation Instructions for XV Control Systems”, dated September 2002 and published by the assignee of the present invention. See, e.g., FIG. AD6-10 on page AD6-6 of that document.
It is an object of the present invention to provide a mechanical thermal detector and a fire suppression system associated therewith which avoids the limitations of the prior art.
According to a preferred embodiment of the present invention, a fire suppression apparatus includes a container of a fire suppressant and an actuation head for releasing the fire suppressant from the container. The system further includes a thermal detector having an energy storage system. The energy storage system includes a movable member (which moves between a first position and a second position) and a biasing member for urging the movable member to the second position. The thermal detector further includes a thermal housing having a degradable member. The degradable member is positioned holding the moveable member in the first position against a bias of the biasing member. The degradable member is selected to degrade in response to an elevated temperature. A transmission member transmits an actuating signal to the actuation head in response to movement of the movable member to the second position. The actuation head is adapted to be activated in response to the signal. The signal may be movement of a mechanical coupling or may be an electrical signal generated by a control member coupled to the thermal detector.
With reference now to the various drawing figures in which identical elements are numbered identically throughout, a description of the preferred embodiment of the present invention will now be provided. In a preferred embodiment, the present invention is provided to activate a fire suppression system on a marine vessel or the like. However, it will be appreciated that the present invention is applicable to a wide variety of applications including vehicles, buildings or other structures.
With initial reference to
The actuation head 14 includes a valve (not shown) for release of the suppressant from the container 12 upon actuation of the head 14. Such actuation permits the flow of the pressurized suppressant through a discharge pipe 15 to a nozzle 16.
It will be appreciated that cylinders for containing a pressurized fire suppressant are commercially available items. An example of such is commercial product 83-131010-001 of Kidde Fenwal, Ashland, Mass., U.S.A. or 372555 of Kidde Aerospace, Wilson, N.C., U.S.A. Actuation heads are also well known products and an example of such is product part no. 979469 of Kidde Fenwal, Ashland, Mass., U.S.A. Such actuation heads 14 actuate a movable valve, which moves from a closed position (preventing release of suppressant from the container 12) to an open position (discharging suppressant through the discharge pipe 15 and nozzle 16) upon movement of the valve.
The present invention includes a novel arrangement for detecting a fire and actuating the actuation head 14. The novel actuation mechanism includes a thermal detector 20 connected to the actuation head 14 by a transmission member 22. In the preferred embodiment of
With reference to
The housing 24 is mounted in a location for detecting elevated temperatures resulting from a fire. The cover 28 includes a plurality of hot air vents 30 for admitting flow of hot air from a fire threat environment to an interior 32 of the housing 24.
Contained within the housing interior 32 are a thermal sensor 34 and an energy storage system 36. The energy storage system 36 and thermal sensor 34 are mounted on the support plate 26.
The thermal detector includes spaced apart first and second fixed members 40, 44, each mounted in a fixed position on the support plate 26. Parallel and spaced apart bars 42 extend between the plates 40, 44.
The plates 40, 44 and bars 42 define a track, which carries a movable member 46 in the form of a plate having holes, which receive the bars 42. Accordingly, the plate 46 can move on the bars 42 between the plates 40 and 44 in a linear path.
With the movable member 46 adjacent the second fixed plate 44, the movable member 46 is in a first position associated with a loaded state in which a fire is not detected and the actuation head 14 is not activated (
Springs 48 are provided as biasing members extending between the first fixed member 40 and a movable member 46. Accordingly, when the movable member 46 is in the first position adjacent the second fixed plate 44 (
First and second linkages 50, 50a connect the first fixed member 40 and the movable member 46. Each of the linkages 50, 50a includes a first lever arm 52, 52a pivotally connected to the first fixed member 40 at a pivot connection 54, 54a. The linkages 50, 50a further include a second lever arm 56, 56a pivotally connected to the movable member 46 at a pivot connection 58, 58a. The first and second lever arms 52, 56 and 52a, 56a are joined at pivot pins 60, 60a.
The combined length of the lever arms 52, 56 and 52a, 56a is greater than the spacing between the first and second fixed members 40, 44. The length is selected so that, when the movable member 46 is adjacent the second fixed member 44, the longitudinal axes of the connected lever arms 52, 56 and 52a, 56a are substantially aligned as illustrated in
Accordingly, as detector 20 is cocked to the loaded position of
The thermal sensor 34 surrounds the opposing pins 60, 60a to hold the opposing pins 60, 60a in their position of
In the embodiments of
In response to an elevated temperature, the thermal sensor 34 degrades by melting. This degradation causes the movable member 46 to move toward the first member 40 in response to the bias of the springs 48. This motion results in displacement of the cable 22, which is connected to a valve (not shown) of the actuator 14, to move the valve of the actuator 14 to an open position resulting in release of the suppressant from the container 12.
In the embodiment of
With the invention thus described, the energy storage system (which in a preferred embodiment includes the spring members 48) is housed in the same housing 24 as the thermal sensor 34 (both of which may be remote from the suppressant container 12). With this embodiment, the cable 22 need not be maintained under precise tension as was the limitation with prior art designs. Further, equipment necessary to maintain desired cable tension in the prior art (such as pulleys and brackets and the like), are eliminated with the design on the present invention.
It has been shown how the objects of the invention have been attained in a preferred embodiment, modifications and equivalents of the disclosed concepts may occur to one of ordinary skill in the art. The invention is adapted to many different uses in addition to those described above. It is intended the modifications and equivalents shall be included within the scope of the claims, which are appended hereto.
