Water mist fire suppression sprinkler

A water seat is provided for use in a fire suppression sprinkler. The water seat is movable between an inactive position and an active position. The water seat includes a generally polygonal guiding surface in limited contact with the sprinkler. The water seat is slidable relative to the sprinkler when corrosion residue is present within the sprinkler. A sealing surface is positioned adjacent the polygonal guiding surface and forms a line contact seal at an interface with the sprinkler when the water seat is in an active position. The water seat also includes a guiding portion adjacent the sealing surface and opposite the polygonal guiding surface. The combination of the guiding surface and the guiding portion maintain a generally parallel orientation of the water seat relative to the sprinkler when the water seat moves from an inactive position to an active position.

BACKGROUND OF THE INVENTION

The invention relates generally to fire suppression systems and, more particularly, to a fire suppression system having a low flow rate.

Fire suppression systems typically involve sprinklers positioned strategically within an area where fire protection is desired. The sprinklers generally remain inactive most of the time. Even though the sprinklers are inactive, many systems include a fire suppression fluid within the conduits to be supplied to the sprinklers. Because the fluid is pressurized, it is necessary to maintain an adequate seal, such as with a water seat for example, to prevent any leaks at the sprinklers while they are inactive.

The geometry of the water seat allows the orientation of the water seat to vary relative to the sprinkler housing. For example, the seal formed between the water seat and a surface of the housing will change depending on the orientation of the water seat relative to the housing when the sprinkler is activated. The orientation of the water seat may, therefore, affect the K-factor, or flow rate, of the sprinkler. Previously known sprinklers, such as those having a K-factor of 4.1 for example, have a flow rate tolerance of about ±0.2; therefore leakage of fluid from the base of the housing is not critical. However, water mist sprinklers used in some applications, such as residential applications for example, operate at substantially lower flow rates. Because the flow rate of such applications is lower, having a K-factor of around 2.4, the absolute tolerance of the flow rate for such applications is also substantially lower, about ±0.1. Consequently, the limited tolerance of the flow rate requires that no uncontrolled flow is present when the water mist sprinkler is active.

BRIEF DESCRIPTION OF THE INVENTION

According to one embodiment of the invention, a water seat for use in a fire suppression sprinkler is provided. The water seat is movable between an inactive position and an active position. The water seat includes a generally polygonal guiding surface in limited contact with the sprinkler. The water seat is slidable relative to the sprinkler when a corrosion residue is present within the sprinkler. A sealing surface is positioned adjacent the guiding surface and forms a line contact seal at an interface with the sprinkler when the water seat is in an active position. The water seat also includes a guiding portion adjacent the sealing surface and opposite the guiding surface. The combination of the guiding surface and the guiding portion maintain a generally parallel orientation of the water seat relative to the sprinkler when the water seat moves from an inactive position to an active position.

According to another aspect of the invention, a fire suppression sprinkler is provided including a housing having at least one channel for discharging a fire suppression fluid. The sprinkler also includes a water seat movable between an inactive and an active position. The water seat includes a generally polygonal guiding surface in limited contact with the sprinkler housing. The water seat is slidable relative to the housing when a corrosion residue is present within the housing. A sealing surface is disposed adjacent the polygonal guiding surface, and a guiding portion is located adjacent the sealing surface and opposite the polygonal guiding surface. When the water seat is in an active position, the water seat is in a generally parallel orientation relative to the housing and forms a line contact seal with an inside surface of the housing.

According to yet another aspect of the invention, a method for sealing an active fire suppression sprinkler is provided including breaking an activator bulb. After the activator bulb is broken, a water seat moves from an inactive to an active position when a corrosion residue is present within the sprinkler. The orientation of the water seat is maintained relative to the sprinkler, and a line contact seal is formed to prevent the fire suppression fluid of the sprinkler from leaking out a first end of the sprinkler.

DETAILED DESCRIPTION OF THE INVENTION

Referring now toFIG. 1, an exemplary fire suppression sprinkler20configured to discharge a mist of fire suppression fluid, such as water for example, is illustrated. The sprinkler20includes a housing22that establishes a flow path24through at least a portion of the housing22. For example, the sprinkler housing22may include a plurality of channels26extending from the center of the sprinkler20outwards, such that the fire suppression fluid will be discharged through these channels26to a space outside the sprinkler20. Disposed within the center of the sprinkler20is a water seat30movable between an inactive and an active position. When the sprinkler20is inactive, the water seat30is configured to block the flow path24. An activator bulb50, positioned between the water seat30and an adjustment member52located at a first end21sprinkler20, retains the water seat30in an inactive position. The activator bulb50operates in a known manner for maintaining the sprinkler20in an inactive condition under most circumstances. Under an elevated temperature, such as in the presence of a fire for example, a fluid within the activator bulb50expands, causing the bulb to break, thereby allowing the sprinkler20to become active in a known manner.

When the water seat30is located in the inactive position, a seal32is disposed adjacent a portion of the water seat30. The illustrated sprinkler20also includes a support ring34within the housing22. In one embodiment, the support ring34is a separate piece inserted within the housing. In another embodiment, the support ring34is formed as part of the housing22. The seal32is received between the support ring34and the water seat30to block the flow path24and to maintain the fire suppression fluid under pressure within the sprinkler20without any leaks. A spring40for biasing the seal32into engagement with the water seat30is positioned at a second end23of the sprinkler20. An end of the spring40is received adjacent a rim42of a flow restrictor component44. In an exemplary embodiment, the spring40urges the flow restrictor component44and the seal32in an axial direction, along central axis A, toward the water seat30. The spring40ensures that the interface between the seal32and the water seat30provides an adequate seal to the flow path24, regardless of whether the fluid pressure within the sprinkler20is sufficient to maintain the seal. The sprinkler20may additionally include an O-ring seal54. Initial pressurization of the sprinkler20forces the O-ring seal54into a position adjacent the seal32, the support ring34, and the housing22to seal a fluid passage that may otherwise exist between an exterior of the seal32and an interior surface of the housing22. The illustrated fire suppression sprinkler20is exemplary and other fire suppressions sprinklers having varying configurations are within the scope of this invention.

FIGS. 2 and 3illustrate an exemplary water seat30for use in a fire suppression sprinkler20. The water seat30includes a generally frustoconical top surface70, a portion of which engages the seal32(FIG. 1) to block the flow of the fire suppression fluid when the water seat30is in an inactive position. A shaft72connects the top surface70to a generally polygonal guiding surface74. In one embodiment, the generally polygonal guiding surface is hexagonal. In another embodiment the polygonal guiding surface is octagonal. The polygonal guiding surface74generally limits the non-vertical movement of the water seat30relative to the housing22(FIG. 1) of the sprinkler20. Adjacent the surface of the guiding surface74, opposite the shaft72, is a generally conical sealing surface76. When the water seat30moves into an active position, the conical sealing surface76will contact a portion of the housing22to prevent the fire suppression fluid from leaking through the first end21of the sprinkler20. The diameter of the conical sealing surface76is largest adjacent the guiding surface74, and gradually decreases along the length of the sealing surface76.

Disposed between an end of the sealing surface76and the bottom surface80of the water seat30is a guiding portion78. The guiding portion78is similarly conical in shape and has a larger diameter adjacent the sealing surface76and a smaller diameter adjacent the bottom surface80. In one embodiment, the change in diameter along the length of the guiding portion78is larger than the change in diameter along the length of the sealing surface76. The guiding portion78in combination with the polygonal guiding surface74aligns the water seat30with the housing22in a desired orientation when the water seat30moves to an active position. In one embodiment, a substantially shallow groove82extends from the bottom surface80into the generally conical guiding portion78such that a portion of the activator bulb50(FIG. 1) may extend into the groove82for retaining the water seat30in an inactive position.

Referring now toFIG. 4, a cross-sectional view of an active fire suppression sprinkler20is illustrated. After the activator bulb50has broken, the pressure of the fire suppression fluid will move the water seat30from a first inactive position (FIG. 1) to a second active position. Because the polygonal guiding surface74has a plurality of sides, the guiding surface74is in limited contact, such as point contact for example, with the housing22that generally occurs at the intersection of adjacent sides of the guiding surface74. This limited contact between the guiding surface74and the housing22loosely retains the water seat30in a centered position within the housing22while the water seat30moves from an inactive position to an active position. In addition, this limited contact allows the water seat30to be easily moved within the housing22when the sprinkler20is activated, even when corrosion residue and other debris are present inside the sprinkler20as a result of certain environmental conditions. The guiding portion78of the water seat30ensures that the water seat30is substantially aligned with central axis A and the housing22when the water seat30contacts an inside surface84of the housing22. As the water seat30moves to an active position, the pressure of the fire suppression fluid wedges the conical sealing surface76against the inside surface84of housing22to create a line contact seal. In one embodiment, the line contact seal is formed at a portion of the sealing surface76adjacent the guiding portion78.

The geometric features of the water seat30create an improved fire suppression sprinkler20. By ensuring that the water seat30is in a vertical position, parallel to the housing22when the line contact seal is formed, the efficacy of the seal is improved, and the leakage of the sprinkler20is thereby greatly reduced. The limited contact between the guiding surface74and the housing22permits movement of the water seat30even under corrosive conditions. Additionally, only a small movement of the water seat30, generally in the range of between 0.3 mm to 1.4 mm is required to activate the sprinkler20and allow a flow of the fire suppression fluid.