Discharge head and fire protection system utilizing said head

Abstract

A fire protection system and discharge head utilized in the system in which the head is actuated by a release of a thermal responsive link for permitting extinguishant to discharge from the head. One or more shear pins are provided which connect a cap over the discharge opening of the head, and which are adapted to break in response to a predetermined extinguishant pressure existing in each head to release the cap and allow the head to open. In the event the temperature in the vicinity of the head reaches a predetermined relatively high value, the head will open despite the absence of the above-mentioned predetermined extinguishant pressure.

Description

BACKGROUND OF THE INVENTION

This invention relates to a fire protection system and a discharge head utilized in the system and, more particularly, to such a system and head in which the opening of each head is controlled in response to predetermined conditions.

Automatic sprinkler systems for protecting industrial and commercial properties and employing thermally releasable discharge heads for installation near the top of the space to be protected are well known. The discharge heads utilized in such systems are supplied with a suitable extinguishant, such as water, by a pipe network of mains, risers, crossmains, and branches. A majority of the heads used in these systems are in the form of "sprinkler heads" that have a discharge opening normally closed by a plug retained by a thermal fuse and a collapsible linkage bridging an external loop or yoke. Upon actuation of the head by collapse of the linkage, the extinguishant stream issuing from the throat impinges against a serrated deflector disc to form a hemispherical pattern of droplets simulating the characteristics of rain.

However, in buildings where the heat of a localized high-challenge fire establishes a fire column or plume of heights in excess of 20 feet, the fire plume often flares out beneath the ceiling of the protected space and directly actuates numerous heads located at such a distance from the fire that they are ineffective to deliver the extinguishant to the surfaces of the materials stored in the building, while the effects of convection and the circulation of hot combustion products throughout the space contribute to the actuation of still more remotely located heads. This contributes not only to redundant and flooding use of the extinguishant but, more significantly, robs extinguishant from the heads located more directly over the fire where it is much more needed.

In U.S. Pat. No. 3,682,251 issued on Aug. 8, 1972, and assigned to the same assignee as the present invention, a fire protection system is disclosed in which a plurality of discharge heads are adapted to be thermally actuated in response to a predetermined temperature. However, the number of actuated heads that are actually opened are limited by means of a "pressure floor" in which a predetermined extinguishant pressure at each individual head must be exceeded before the head will open.

Although this type system and discharge head have considerable advantages, it was found to be extremely desirable to actuate the heads at a relatively low temperature, such as approximately 150.degree.-200.degree., to insure that heads located immediately above the fire would open in a relatively quick manner after initiation of a fire and begin to discharge extinguishant towards the fire to fight it at its early stages. However, this relatively low actuation temperature often caused several of the heads to be actuated prematurely due to the fact that their temperature responsive mechanisms were more susceptible to external factors, such as air currents, ambient temperatures, and the convective circulation of gaseous products of combustion, etc. As a result, the heads would often be prevented from opening in a logical sequence, i.e., in direct proportion to their distance from the location of the fire. This plus the fact that the above-mentioned pressure floor would limit the number of heads that opened also often resulted in heads being opened which were located a greater distance from the fire than heads that were prevented from opening.

A way of overcoming this illogical operation would be to raise the response temperature of the individual heads, such as to a value of approximately 350.degree.-450.degree.. In this manner, the above-mentioned external influences prevailing in the building would have less effect upon the heads, and the heads located the closest to the fire would open in a logical sequence. However, the existence of this relatively high response temperature causes the system to respond slowly to the existence of a fire, often to an extent that would permit the fire to reach proportions that rendered it impossible to extinguish.

Another problem associated with the relatively low actuation temperature-pressure floor design was that, in the event some of the heads, after being actuated, were prevented from opening due to lack of pressure, they remained closed even if the magnitude of the fire increased to the extent that discharge of extinguishant from all available sources was essential, despite the lack of the predetermined pressure.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide a fire protection system and a discharge head utilized therein in which each head will open upon the existence of a predetermined temperature and extinguishant pressure.

It is a further object of the present invention to provide a system and head of the above type in which each head will open in response to the existence of a predetermined, relatively high, temperature regardless of the value of the extinguishant pressure.

It is a further object of the present invention to provide a system and head of the above type in which the response mechanism in the head is relatively precise in operation, yet inexpensive in cost.

Towards the fulfillment of these and other objects, the discharge head utilized in the system of the present invention comprises a body member having an inlet for connecting to a source of pressurized extinguishant and an outlet for discharging said extinguishant, closure means for said outlet, linkage means for applying a force against said blocking means greater than, and in an opposite direction to, the force of said pressurized extinguishant against said closure means to retain said blocking means in an operative position relative to said outlet where it prevents the discharge of fluid from said outlet, said linkage means adapted to respond to a predetermined fire condition in its vicinity for releasing its force, at least one shear pin connecting said closure means to said body member in said operative position, said shear pin adapted to break and release said closure means in response to the pressure of said extinguishant exceeding a predetermined value, said closure means being forced from said operative position by said extinguishant upon the existence of said fire condition and said predetermined extinguishant pressure to permit the discharge of said extinguishant from said outlet.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of a building having the sprinkler heads forming the system of the present invention installed therein;

FIG. 2 is a perspective view of a sprinkler head utilized in the present invention;

FIG. 3 is an exploded view of several components of the head of FIG. 2, and;

FIG. 4 is a cross-sectional view taken along the line 4--4 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1 of the drawings, a building 10 is shown in phantom lines which is equipped with an automatic fixed fire protection system embodying features of the invention. The system comprises a buried feed main 12 connected to a municipal water supply line 14 for delivering the extinguishant, in this case water, via a horizontal line 16, to a riser 18. The riser 18 is connected to a piping system which is suspended near the ceiling of the building 10 in a conventional manner. The piping system includes a crossmain 20 which is connected to a plurality of branch lines 22 spaced along the crossmain and extending perpendicular thereto. The riser 18 is connected to a free end of one of the branch lines 22 for supplying water to the crossmain 20 which, in turn, supplies the water to the other branch lines 22. Each of the other branch lines 22 has a plurality of sprinkler heads 24 mounted thereon in a spaced relationship which are operated automatically in response to a fire occurring in the building, as will be described, to deliver a spray of water to the fire. The buried feed main 14 extends beyond the riser 18 and can be connected to risers of other buildings or, in the case of a large building, to other risers in the same building.

A sprinkler head 24 is shown in FIG. 2 and consists of a base member 26 having an externally threaded inlet portion 28 projecting from one end thereof for connection to an internally threaded opening (not shown) in a branch line 22. A tubular member 30 projects from the other end of the base member 26 and communicates with the inlet portion 28 through an opening in the base member 26. The tubular member 30 defines a discharge opening at its free end which is normally covered by a cap, or disc, 32, as will be described in detail later.

A yoke 34 is supported by the base member 26 and, in turn, supports a serrated deflector disc 36 at its apex. A collapsible linkage assembly, comprising two substantially T-shaped lever arms 38 and 40, is supported by the yoke 34. One projecting portion of the lever arm 38 engages the cap 32 to maintain it over the discharge opening defined by the tubular member 30, while one projecting portion of the lever arm 40 is supported by the apex of the yoke 34. The other projecting portions of the lever arms 38 and 40 engage each other, while the ends of the lever arms are engaged by a fusible link 42 extending thereover in a manner to apply a force to the lever arms 38 and 40 of a sufficient amount to maintain the lever arms in the position shown. The fusible link 42 may be of any standard material, such as solder, which is adapted to fuse, or melt, at a predetermined elevated temperature, and release itself from the engagement with the lever arms 38 and 40.

FIG. 3 is an exploded view of the tubular member 30, the cap 32, and their associated components. In particular, a gasket 44 is provided for extending over the free end of the tubular member 30, and thus between the latter end and the inner face of the cap 32. A pair of L-shaped mounting brackets 46 are connected to two diametrically opposed portions of the outer wall of the tubular member 30 by shear pins 48 which extend through openings formed in the members 36 and the latter wall. A pair of lips 50 extend from diametrically opposed portions of the outer edge of the cap 32 and are sized to correspond to one leg portion of each of the brackets 46. The shear pins 48 are designed to break in response to a predetermined shear stress being placed thereon as will be described in detail later.

The components of FIG. 3 are shown in an assembled condition in FIG. 4. It is noted that a strip 60 of solder extends between the lower surfaces of the lips 50 of the cap 32 and the corresponding upper surfaces of the leg portions of the bracket members 46, as viewed in FIG. 4. This secures the cap 32 relative to the brackets 46 and therefore in a position closing the discharge opening defined by the upper end portion of the tubular member 30. The solder strips 60 are selected to melt at an elevated predetermined temperature in excess of that required to melt the fusible link 42, and thus release the connection between the cap 32 and the brackets 46. For the purposes of example, the fusible link can be selected to fuse at a temperature of approximately 286.degree.F., while the solder strips 60 may be selected to fuse at a temperature of approximately 500.degree.F.

In operation, the heads 24 are installed in the position shown in FIG. 1, with the pressure of the extinguishant supplied to each head being insufficient to discharge its cap 32 from the outlet opening defined by the free end portion of the tubular member 30 due to the oppositely-directed force applied to the disc 32 by the lever arms 38 and 40. Upon the temperature in the vicinity of one or more of the heads 24 reaching the fusible temperature of its link 42 which, for the purposes of example, is 286.degree.F., the link 42 will fuse and fall downwardly and the linkage assembly formed by the lever arms 38 and 40 will collapse. Despite this, the cap 32 will still be secured in the position shown in FIGS. 2 and 4 by the shear pins 48 securing the brackets 46 to the tubular member 30, and by the solder strips 60 between the brackets 46 and the lips 50 of the cap 32. If the force applied to the exposed inner surface of the cap 32 by the pressure of the water in the tubular member 30 is of a magnitude to break the shear pins 48, the brackets 36, and therefore the cap 32, will be freed for release from the discharge opening under the pressure of the water, thus permitting the water to discharge from the tubular member 30.

After fusing of the link 42, in the event the water pressure in the tubular member 30 is not sufficient to break the shear pins 48, the cap 32 will remain in the position shown, thus preventing the discharge of the water from the tubular member 30. However, if the temperature in the vicinity of the head rises to the extent that it reaches the melting temperature of the solder strips 60, which, for the purposes of example, is 500.degree.F., the cap 32 will release from the bracket members 46 and the water will discharge through the discharge opening, despite the absence of a predetermined water pressure in the tubular member 30. This, of course, provides a failsafe opening of each head in the event the magnitude of the fire increases to the extent that it is no longer desirable to prevent the heads from opening.

In the event that one or more of the heads 24 are opened under the above conditions, the resulting stream of water issuing from the discharge opening will impinge against the serrated deflector disc 36 to form a hemispherical pattern of droplets a portion of which will extend in a radial direction relative to the discharge opening and eventually fall onto the fire, simulating the characteristics of rain.

It is thus seen that according to the present invention each head can be designed to respond to a predetermined temperature and water pressure depending on the fusion temperature of its link 42 and the pressure that will cause a breaking of the pins 48. In this manner, the system can be designed to insure that after a predetermined number of heads 24 have been opened, any additional heads will not be opened despite the fusion of their fusible links 42 unless the temperature rises to the predetermined level sufficient to melt the solder strips 60. As discussed above, this eliminates the redundant and flooding use of water and prevents heads located a fairly remote distance from the actual location of the fire from being opened and therefore robbing water from the heads directly over the fire in the area where it is critical that they have sufficient pressure, while also permitting failsafe opening of each head in the event a potentially disastrous fire situation is occurring.

It is understood that variations in the type of extinguishant used, as well as other variations of the specific construction and arrangement of the fire protection system and discharge head disclosed above can be made by those skilled in the art without departing from the invention as defined in the appended claims.

Claims

I claim:

1. A discharge head for use in a fire protection system comprising a body member for containing pressurized extinguishant, said body member having an inlet for connecting to a source of said extinguishant and an outlet for discharging said extinguishant, closure means for said outlet, linkage means for applying a force against said closure means greater than, and in an opposite direction to, the force of said pressurized extinguishant against said closure means to retain said closure means in an operative position relative to said outlet where it prevents the discharge of fluid from said outlet, said linkage means adapted to respond to a predetermined fire condition in its vicinity for releasing its force, at least one shear pin connecting said closure means to said body member in said operative position, said shear pin adapted to break and release said closure means in response to the pressure of said extinguishant exceeding a predetermined value, said closure means being forced from said operative position by said extinguishant upon the existence of said fire condition and said predetermined extinguishant pressure to permit the discharge of said extinguishant from said outlet.

2. The head of claim 1 wherein said closure means includes at least one bracket member, a cap extending over said outlet, and means for securing said cap to said bracket member, said shear pin connecting said bracket member to said body member.

3. The head of claim 2 wherein said means for securing said cap to said bracket member comprises solder connected to said cap and said bracket member and adapted to melt at a predetermined temperature for releasing said cap from said bracket member under the force of said extinguishant and permit said extinguishant to discharge from said outlet.

4. The head of claim 3 wherein said predetermined fire condition is a temperature of a lower value than that required to melt said solder.

5. The head of claim 1 further comprising deflector means supported on said body member in a spaced relation to said outlet for deflecting said extinguishant in a generally radial direction from said body member.

6. A sprinkler head for use in a fire protection system comprising a body member for containing pressurized extinguishant, said body member having an inlet for connecting to a source of said extinguishant and an outlet for discharging said extinguishant, closure means for said outlet, linkage means for applying a force against said closure means greater than, and in an opposite direction to, the force of said extinguishant against said closure means to retain said closure means in an operative position relative to said outlet where it prevents the discharge of extinguishant from said outlet, said linkage means adapted to respond to a predetermined temperature in its vicinity for releasing its force, pressure responsive means for securing said closure means in said operative position, said pressure responsive means adapted to release said closure means in response to the pressure of said extinguishant in said body member exceeding a predetermined value, said closure means being forced from said operative position by said extinguishant upon the existence of said predetermined temperature and said predetermined extinguishant pressure to permit the discharge of said extinguishant from said outlet, means responsive to an additional temperature of greater value than said predetermined temperature for releasing said closure means in the event said closure means is not released in response to the existence of said predetermined temperature and said predetermined extinguishant pressure, and means for deflecting the extinguishant discharge from said outlet in a manner to create a mist-like spray at least a portion of which extends in a substantially radial direction relative to said outlet.

7. A fire protection system comprising a plurality of discharge heads mounted in an elevated position in a space to be protected from fire; and conduit means connected to a source of pressurized extinguishant, each discharge head comprising a body member having an inlet connected to said conduit means and an outlet for discharging said extinguishant, closure means for said outlet, linkage means for applying a force against said closure means greater than, and in an opposite direction to, the force of said pressurized extinguishant against said closure means to retain said closure means in an operative position relative to said outlet where it prevents the discharge of fluid from said outlet, said linkage means adapted to respond to a predetermined fire condition in its vicinity for releasing its force, at least one shear pin connecting said closure means to said body member in said operative position, said shear pin adapted to break and release said closure means in response to the pressure of said extinguishant exceeding a predetermined value, said closure means being forced from said operative position by said extinguishant upon the existence of said fire condition and said predetermined extinguishant pressure to permit the discharge of said extinguishant from said outlet.

8. The system of claim 7 wherein said closure means includes at least one bracket member, a cap extending over said outlet, and means for securing said cap to said bracket member, said shear pin connecting said bracket member to said body member.

9. The system of claim 8 wherein said means for securing said cap to said bracket member comprises solder connected to said cap and said bracket member and adapted to melt at a predetermined temperature for releasing said cap from said bracket member under the force of said extinguishant and permit said extinguishant to discharge from said outlet.

10. The system of claim 9 wherein said predetermined fire condition is a temperature of a lower value than that required to melt said solder.

11. The system of claim 7 further comprising deflector means supported on said body member in a spaced relation to said outlet for deflecting said extinguishant in a generally radial direction from said body member.

12. A fire protection system comprising a plurality of sprinkler heads mounted in an elevated position in the space to be protected from fire; and conduit means connected to a source of pressurized extinguishant, each sprinkler head comprising a body member for containing said pressurized extinguishant, said body member having an inlet for connecting to said conduit means and an outlet for discharging said extinguishant, closure means for said outlet, linkage means for applying a force against said closure means greater than, and in an opposite direction to, the force of said extinguishant against said closure means to retain said closure means in an operative position relative to said outlet where it prevents the discharge of extinguishant from said outlet, said linkage means adapted to respond to a predetermined temperature in its vicinity for releasing its force, pressure responsive means for securing said closure means in said operative position, said pressure responsive means adapted to release said closure means in response to the pressure of said extinguishant in said body member exceeding a predetermined value, said closure means being forced from said operative position by said extinguishant upon the existence of said predetermined temperature and said predetermined extinguishant pressure to permit the discharge of said extinguishant from said outlet, means responsive to an additional temperature of greater value than said predetermined temperature for releasing said closure means in the event said closure means is not released in response to the existence of said predetermined temperature and said predetermined extinguishant pressure, and means for deflecting the extinguishant discharge from said outlet in a manner to create a mist-like spray at least a portion of which extends in a substantially radial direction relative to said outlet.