This invention concerns dry sprinklers for use in sub-freezing ambient conditions.
Sprinkler systems for fire suppression are used to protect structures which separate or enclose adjacent regions having large temperature differences from one another. Examples of such structures include freezers, balconies of apartments, and loading docks of warehouses. Each of these structures has one or more walls and/or ceilings, which separate a region wherein the temperature is maintained above the freezing point of water from a region where the temperature is maintained below freezing or can drop below freezing.
It is a challenge to provide fire protection to such structures, especially when water is the preferred fire suppressing liquid because measures must be taken to ensure that the water does not freeze within the piping network. To meet this challenge it is known to position the piping network in the temperature controlled “warm” environment where water within the pipes will not freeze, and to provide “dry” type sprinkler assemblies which extend from the piping network through openings in the ceiling or walls of the structure and into the “cold” or uncontrolled environment. Such dry sprinkler assemblies have elongated pipe elements extending between the sprinkler and the piping network with a valve inside to maintain the sprinkler assembly in a “dry” state, i.e., without water in the pipe element, until the sprinkler is activated by the heat from a fire. A heat sensitive trigger, for example a liquid filled frangible bulb, which breaks when subjected to heat from a fire, opens the sprinkler to permit discharge of the water and also acts to open the valve and allow water to flow from the piping network through the conduit and out through the sprinkler.
It would be advantageous to provide dry sprinkler assemblies which can achieve flow rates having nominal k factors of 11.2 or greater while using, for example, 1 inch NPS pipe for the pipe element comprising the dry sprinkler assembly which connects to the piping network in the warm environment and which has the sprinkler outlet located in the cold environment. (The k factor is defined as k=q/√p where q is the discharge rate from the dry sprinkler assembly in gallons per minute and p is the pressure within the pipe element in psi (gauge)). It would be particularly advantageous to provide dry sprinkler assemblies having nominal k factors equal to or greater than k17 using 1 inch NPS pipe for the pipe element comprising the dry sprinkler. All known commercially available dry sprinklers of k17, such as the Model ESFR-17 Dry Type Pendent Sprinkler sold by Tyco Fire Products, and the K17 Dry ESFR Pendent Storage Sprinkler sold by Viking Group, Inc., comprise pipe elements having a size of greater than 1 inch NPS pipe. Dry sprinklers made of larger pipe sizes weight more, come at greater cost, and are more challenging to install. There is clearly a need to provide dry sprinklers of k factor 11.2 and greater, particularly, k-factor 17, comprising pipe elements of size 1 inch NPS.
The invention concerns a dry sprinkler assembly for use with a piping network of a fire suppression system. In one example embodiment, the dry sprinkler assembly comprises a 1 inch NPS pipe element having a first end attachable in fluid communication with the piping network. In a practical design it is advantageous that the 1 inch NPS pipe element have a wall thickness less than 0.095 inches. A valve is positioned within the pipe element proximate to the first end. The valve has a first closing member movable between a closed position preventing fluid flow through the pipe element, and an open position permitting fluid flow through the pipe element. A fire suppression sprinkler is mounted on a second end of the pipe element. The sprinkler defines a bore in fluid communication with the pipe element. In an example embodiment the sprinkler comprises a second closing member in engagement with the bore. A temperature sensitive trigger is engaged with the second closing member and maintains the second closing member in engagement with the bore until an ambient temperature exceeds a predetermined threshold. The trigger releases the second closing member from the engagement with the bore when the ambient temperature reaches or exceeds the predetermined threshold thereby permitting fluid flow through the pipe element, wherein when the first closing member is in the open position and the second closing member is released from engagement with the bore, the sprinkler assembly achieves a discharge rate equal to or greater than a k factor of 17.
By way of example, the assembly may further comprise a tube coaxially positioned within the pipe element. The tube has an outer perimeter smaller than an inner perimeter of the pipe element and is moveable lengthwise along the pipe element. The first closing member is mounted on a first end of the tube, a second end of the tube is engaged with the second closing member when the second closing member is in the engagement with the bore.
By way of example, the tube has a round cross section with an outer diameter smaller than an inner diameter of the pipe element. In a further example embodiment, the tube comprises a sidewall defining a plurality of openings therethrough. In an example embodiment, the openings comprise a plurality of slots oriented lengthwise along the tube. In an example embodiment, a portion of the sidewall proximate to the second end of the tube has no openings therethrough. By way of example, the openings may comprise at least 30% of a surface area of the sidewall.
In an example assembly embodiment, the valve comprises a seat mounted proximate to the first end of the pipe element. The first closing member is engageable with the seat. By way of example the first closing member comprises a platform pivotably mounted on the first end of the tube. An obturation body is mounted on the platform. The obturation body is pivotable between a first position facing the seat and engageable therewith, and a second position angularly oriented relative to the seat. In a specific example embodiment the obturation body comprises a Bellville washer.
In an example embodiment a pivot support is mounted on the first end of the tube. The platform is pivotably mounted on the pivot support. A stop surface is positioned on the pivot support. A projection extends from the platform and is engageable with the stop surface to limit pivoting motion of the platform. Further by way of example, a biasing member acts between the tube and the platform for biasing the obturation body into the second position.
In an example embodiment the sprinkler comprises a body defining the bore. A pair of arms extend from the body away from the second end of the pipe element. A deflector plate is mounted on the arms. The trigger is positioned between the deflector plate and the second closing member. The trigger may comprise a frangible vial filled with a heat sensitive liquid.
In an example embodiment the sprinkler comprises at least one stop surface engageable with the tube to limit sliding motion thereof relative to the pipe element. In a specific example, the stop surface comprises at least one projection extending from one of the arms. An example sprinkler may further comprise a nipple extending from the body. The nipple may have male screw threads thereon. In another example embodiment the sprinkler comprises a shoulder on the body. The shoulder projects into the bore and defines the stop surface. In this example embodiment the tube comprises at least one detent projecting outwardly therefrom. The at least one detent is positioned in spaced relation from the second end of the tube and is engageable with the stop surface upon motion of the tube within the pipe element. In a specific example embodiment the shoulder comprises an annulus surrounding the bore. Further by way of example, the body may comprise female threads surrounding the bore. A pair of arms extend from the body away from the second end of the pipe element. In a particular example embodiment the second end of the pipe element has male screw threads thereon engaging the female threads surrounding said bore. A deflector plate is mounted on the arms. The trigger is positioned between the deflector plate and the second closing member.
In a further example embodiment according to the invention, the second closing member comprises a plug. In a specific example, the plug comprises a plurality of plug bodies engageable with the bore. The plug bodies defining a gap permitting draining of condensate from the pipe element. This example embodiment may further comprise a trigger bearing engageable with the plurality of plug bodies and the trigger.
The invention also encompasses a dry sprinkler assembly for use with a piping network of a fire suppression system, the dry sprinkler assembly having a discharge rate equal to or greater than a k factor of 11.2. In an example embodiment the dry sprinkler assembly according to the invention comprises a 1 inch NPS pipe element having a first end attachable in fluid communication with the piping network. In a practical design it is advantageous that the 1 inch NPS pipe element have a wall thickness less than 0.095 inches. A valve is positioned within the pipe element proximate to the first end. The valve has a first closing member movable between a closed position preventing fluid flow through the pipe element, and an open position permitting fluid flow through the pipe element. The valve comprises a seat mounted proximate to the first end of the pipe element. The first closing member is engageable with the seat. A tube is coaxially positioned within the pipe element. The tube has an outer perimeter smaller than an inner perimeter of the pipe element and is moveable lengthwise along the pipe element. The first closing member is mounted on a first end of the tube. By way of example the first closing member comprises a pivot support mounted on the first end of the tube. A platform is pivotably mounted on the pivot support. An obturation body is mounted on the platform. The obturation body is pivotable between a first position facing the seat and engageable therewith, and a second position angularly oriented relative to the seat. A stop surface is positioned on the pivot support. A projection extends from the platform and is engageable with the stop surface to limit pivoting motion of the platform. A fire suppression sprinkler is mounted on a second end of the pipe element. The sprinkler defines a bore in fluid communication with the pipe element. By way of example the sprinkler further comprises a second closing member in engagement with the bore. A second end of the tube is engaged with the second closing member when the second closing member is in engagement with the bore. A temperature sensitive trigger is engaged with the second closing member and maintains the second closing member in engagement until an ambient temperature exceeds a predetermined threshold. The trigger releases the second closing member from the engagement with the bore when the ambient temperature reaches or exceeds the predetermined threshold. When the first closing member is in the open position and the second closing member is released from the engagement, the sprinkler assembly achieves a discharge rate equal to or greater than a k factor of 11.2.
As shown in
A valve 50 is positioned within pipe element 12 proximate to the first end 16. In the example embodiment shown in
As shown in
As shown in
In operation the assembly 10 is attached to a branch line of a fire suppression system (not shown) using nipple 18, which may be threaded as shown or provided with a groove for use with mechanical couplings. Assembly 10 is initially in the “loaded” configuration shown in
In another example embodiment, shown in
As shown in
Dry sprinkler assemblies according to the invention are expected to improve both the reliability and effectiveness of fire suppression systems while using 1 inch NPS pipe for the pipe element connecting the piping network in the warm environment to the sprinkler located in the cold environment. The discharge rate of dry sprinkler assemblies according to the invention is expected to be equal to or greater than a k factor of 11.2, wherein the k factor is defined as k=q/√p where q is the discharge rate from the assembly 10 in gallons per minute and p is the pressure within the pipe element 12 in psi (gauge).
This application is based upon and claims benefit of priority to U.S. Provisional application No. 62/721,753, filed Aug. 23, 2018 and hereby incorporated by reference herein.
Number | Date | Country | |
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62721753 | Aug 2018 | US |