US3685588A

US3685588A - Discharge head for a fixed fire-extinguishing system

Info

Publication number: US3685588A
Application number: US159406A
Authority: US
Inventors: William L Livingston
Original assignee: Factory Mutual Research Corp
Current assignee: Factory Mutual Research Corp
Priority date: 1971-07-02
Filing date: 1971-07-02
Publication date: 1972-08-22
Anticipated expiration: 1989-08-22

Abstract

A discharge head for fixed fire extinguishing systems of the type in which a fluid extinguishant is supplied under line pressure to a plurality of such heads. The actuation of the head in response to afire is inhibited when line pressure drops below a predetermined magnitude, thereby preserving the ability of already actuated heads in the system to disperse extinguishant directly on a fire. The discharge head operates to release a stream of extinguishant directly on a fire when a predetermined line pressure is present in the head.

Description

United States Patent Livingston DISCHARGE HEAD FOR A FIXED FlRE-EXTINGUISHING SYSTEM [72] Inventor: William L. Livingston, Sharon,

Mass. [73] Assignee: Factory Mutual Research Corporation, Norwood, Mass.

[22] Filed: July 2,1971 [21] App1.No.: 159,406

[52] U.S.Cl ..169/37,169/l6 [51] lnt.Cl 37/08 [58] 'FieldoiSearch ..l69/37, 16,5

[56] References Cited UNITED STATES PATENTS 1,143,762 6/1915 Hooks ..169/37 2,164,611 1 7/1939 Fortin ..169/37 2,230,179 1/1941 Cid "1 69/37 [151 3,685,588 1 Aug. 22, 1972 11/1945 Tyden ..169/37 Primary Examiner-M. Henson Wood, Jr.

Assistant Examiner-Thomas C. Culp, Jr.

. Attorney-Joseph M. :Lane, Richard L. Aitken,

Donald R. Dunner, Robert F. Ziems. and Warren B. Kice [57] ABSTRACT directly on a'fire. The discharge head operates to release a stream of extinguishant directly on a tire when a predetermined line pressure is present in the head.

Patented Au 22, 1972 3,685,588

F/6.l. 7 F/G.2.

' INVENTOR WILLIAM L. LIVINGSTON BYW ATTORNEYS CROSS-REFERENCES TO RELATED APPLICATIONS U.S. application Ser. No. 864,756, filed Oct. 8, I969 and entitled Fire-Responsive Sprinkler Head. U.S. application Ser. No. 885,501, filed Dec. 16, 1969, and entitled Adaptive Sprinkler Head.

BACKGROUND OF THE INVENTION This invention relates to a fire-responsive discharge head, and more particularly, to such a discharge head which operates only when its inlet pressure is above a predetermined minimum.

Fire protection systems which provide a supply of extinguishant under pressure through a suitable conduit network to a plurality of fire-responsive discharge heads are known in the art. Such systems are intended to retain the extinguishant under pressure for ready release by actuation of a fire-responsive element, such as a thermally-actuated fusible member.

It is an overall problem in the design of such systems, and in designing discharge heads for such systems, to provide for efiective operation of the system under a reduced extinguishant supply pressure. For example, while a single operative discharge head will receive nearly full operating pressure, successive actuation of additional discharge heads will cause the inlet pressure to the discharge heads to decrease which, in turn, causes a deterioration in the effectiveness of the discharge heads which have already opened in response to a fire. Inasmuch as such open heads are most likely in the region of concentrated combustion, it is desirable to maintain the extinguishant flow characteristics of the open head or heads although the exit flow rate of extinguishant at these latter heads has been reduced by the opening of additional heads. Thus, the need has developed for a discharge head which can maintain a flow of extinguishant to its assigned area through a, wide range of line pressures supplying the head.

In the above-identified U.S. application Ser. No. 864,756, which is assigned to same assignee as the present application, and in which the present applicant is a co-inventor, there is disclosed a head which overcomes the problems in the art discussed above. The head disclosed in that application comprises a body which includes an inlet portion for receiving a continuous supply of fire extinguishant and a discharge portion defining a discharge opening. An expellable member is disposed within the body for sealing the discharge opening when the head is in its quiescent state. Fireresponsive means, including a spring-biased trigger member and a fire-sensing member are provided for securing the expellable member within the body of the head. When the firesensing member is actuated, the spring-biased trigger member releases the expellable member so that the expellable member may be ejected through the discharge opening of the head. An O-ring seal is provided between the expellable member and the discharge opening and the frictional characteristics of the seal and the clearances are selected so that the member will not be expelled unless the inlet pressure of the extinguishant exceeds a predetermined minimum.

In the above-identified application Ser. No. 885,501, which is assigned to the same assignee as the present application, and in which the present applicant is the inventor, there is disclosed a head which is a modified version of the head disclosed in application Ser. No.

864,756. The head of application Ser. No. 885,501 utilizes an O-ring seal between the expellable member and the discharge opening so that the member will not be expelled unless the inlet pressure of the extinguishant exceeds a predetermined minimum. Additionally, the latter head is provided with a line pressure responsive means for inhibiting or delaying the fire-responsive release device associated with the head when the pressure of extinguishant at the head is below a predetermined level as a result of the opening of other heads in the system. The line pressure responsive means according to one embodiment involves a heat shield normally positioned by line pressure away from the thermally actuated fuse for actuating the head. When line pressure drops as. a result of other heads in the system being open, the shield is moved to a position around the thermal fuse so as to require a higher ambient temperature in the vicinity of the fuse to bring about actuation of the head.

While both of the foregoing heads are satisfactory for the designed purposes, they suffer from the fact that they have expellable plugs which are released from the head when actuated by a tire. Thus, these heads require a complete reassembly or replacement prior to reuse. Obviously, if heads are operated due to a minor fire, such replacement and/or reassembly can create inconvenience and expense. Also, in uses of heads of this type, there is no compensation for subsequent decreases in the pressure available to the head after the plug is initially expelled.

SUMMARY OF THE INVENTION An object of the present invention is to provide an improved discharge head for a fixed fire extinguishing system.

Another object of the present invention is to provide a discharge head which does not disassemble when actuated and may be reused with little expense and effort. Another object of the present invention is to provide a discharge head which will not open unless there is a predetermined extinguishant pressure available in the head.

Another object of the present invention is to provide a discharge head in which there are means for adjusting the value of the above-mentioned predetermined pressure.

A further object of the present invention is to provide a discharge head which, once opened, will cut off the flow of extinguishant if the pressure thereof falls below a predetermined minimum.

Applicant has discovered that the above objects are accomplished by a discharge head comprising means defining a chamber having an inlet opening for receiving a supply of fire extinguishant at an inlet pressure, a primary discharge opening for establishing a direct flow path for extinguishant from said head to said fire anda secondary discharge opening; flow preventing means for preventing the flowof extinguishant through said primary discharge opening when said head is in its quiescent state; fire-responsive means for preventing flow of extinguishant through said secondary discharge opening when said head is in its quiescent state and for present invention; and

allowing flow of extinguishant through said secondary predetermined value before said flow preventing means is actuated.

' BRIEF DESCRIPTION or THE DRAWINGS Reference is now made to the accompanying drawings for a better understanding of the nature and objects of the present invention. The drawings illustrate the best mode presently contemplated for carrying out the objects of the invention and are not to be construed as restrictions or limitations on its scope. In the drawings:

I FIG. 1 is a view, substantially in cross-section, of an embodiment of a sprinkler headaccording to the FIG. 2 isa partial view, substantially in cross-section, of another embodiment of asprinkler head according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED 3 EMBODIMENT .In FIG. 1, a discharge head according to the invention is designated generally by the reference numeral 1 and comprises a hollow four-way coupling member 2 having fourthreaded

openings

2a, 2b, 2c and 2d, and defining a chamber 3 which registers with the openings. A,branch line 4for supplying extinguishant, such as water, to the head 1 has two portions threadably engaging the

openings

2b and 2d to connect the coupling member 2 in the line.

' A nozzle unit 5 is attached to the coupling member 2 by means of a threaded nipple 6 engaging the opening 2c and the upper portion of the nozzle unit 5 with a primary discharge opening 7 being formed at the lower end of the nozzle unit 5. A hollow cylindrical member 8 is supported within the chamber 3 and has a threaded base portion 9 extending in the opening 2a. The upper end of the cylindrical member 8 is closed by an externally threaded closure member 10 provided with an internally threaded opening 11. A fire detector 12, which will. be discussed in further detail below, has a threaded base portion 13 which is threadably engaged within the opening 11. The interior of the base portion 13 is hollow to form a secondary discharge opening 14.v

A rod 15 extends within the nozzle unit 5, and a plug member 16 is afiixed to an end of the rod and normally forms a water tight seal with the primary discharge opening 7 by means of a pair of sealing rings 17 and 18 extending in annular grooves formed in the plug member.

A pairof swirling vanes 20 are mounted in the upper portion of the nozzle unit 5 as viewed in FIG. 1, and cause the water to flow in a spiral direction through the nozzle unit to impart aconical-like pattern to the spray as itdischarges from the primary discharge opening 7, in a conventional manner.

The rod 15 extends through a central opening formed through the vanes 20 and an extension member the head 21a. Such attachmentis accomplished by and receiving nuts 24a to adjustably compress the 21 is threadably attached to the upper end of the rod. The extension member 21 has-an enlarged disc-like head 21a formed at its free end which extends within the lower end of the cylindrical member 8. A piston washer 22, made of a yieldable material such as a suitable plastic or leather, is attached to theupper surface of sandwiching the washer 22 between the head 21a and aclamping disc 23, and utilizing bolts 24 extending through the disc 23, the washer 22 and the head 21a washer 22.

A pair of radial openings are formed through the extension member 21 which communicate with a central opening formed through the head 210, the washer 22 and the disc 23 to define a pressure equalization port 25 which allows for water communication from the chamber 3 to the interior of the cylindrical member 8.

Located concentrically within the cylindrical member 8 is a constant force helical spring '26 which engages an annular recess in the underside of the closure member 10 and bears on the upper side of the disc 23 to urge the latter, .and therefore the extension member 21 androd l5 downwardly, as viewed in FIG. 1. A spring-locked air bleed check valve'27 is provided in an opening through the cylindrical member 8 and is adapted to relieve the interior of the cylindrical member 8 from air when the interior is initially filled with water. r

The fire detector '12 includes a yoke 28 which supports an upper lever and 30a and a lowerlever a'rm 30bv normally held in place by a fusible link 31; The lower lever arm 30b bears against a disc-like closure member 32 which normally closes off the secondary discharge opening l4. The fusible link 31"is'adapted to fuse, or

, collapse, in response to a predetermined temperature discharge opening 7 and is preferably selected to fuse at the same temperature as thelink 31, tosprovide a redundant opening means for the primary'discharge opening 7, and thus provide a safeguard against'the discharge of water in the event that the fusible link 31' is inadvertently actuated. The nut 35 also prevents an accumulation of dirt and grime in the discharge openin g 7 which may otherwise affect the flow of water from the opening in the event of fire. I r

The head 1, along with a number of identical heads forming the system, is installed in an elevated position in the space to be protected from fire in the position shown in FIG. 1, i.e., with the fusible link 31 supporting the lever anns 30a and 30b and with the fusible nut 35 positioned in the discharge opening 7.The water supplied to the head by the branch line 4 via suitable risers, submains, etc., is maintained under pressure in the head, with the port 25 permitting the water to flow from the chamber 3 into the interior of the cylindrical member 8, whereby it'accumulates and thus balances the hydraulic forces across the piston washer 22. As a result, the rod 15 and the plug member 16 maintain their positions shown in FIG. 1 due to the force of the spring 26, the frictional force between the outer periphery of the washer 22 and the corresponding inner I wall portion of the nozzle unit 5, and the force acting on the upper surface of the plug member 16 as a result of the water pressure in the head.

Upon the occurrence of a fire sufficient to fuse the fusible link 31 and the fusible nut 35, the

lever arms

30a and 30b are freed and the closure member 32 is released from its blocking position over the secondary discharge opening 14, permitting a discharge of the water from the interior of the cylindrical member 8 via the latter opening. If the force acting on the exposed lower surfaces of the head 21a and the washer 22 as a result of the water pressure within the chamber 3 is at a level to overcome the force of the spring 26, the preset breakaway friction between the piston washer 22 and the inner walls of the cylindrical member 8, and the force as a result of the water pressure acting on the upper surface of the plug member 16, the plug member will retract upwardly from the primary discharge opening 7 and allow extinguishant to discharge through the latter opening directly towards the fire. After the above-mentioned initial breakaway frictional force is exceeded, the spring 26 provides substantially all of the resistance to upward movement of the plug member 16 caused by the above-mentioned pressure differential acting on the exposed lower surfaces of the head 21a and the washer 22, as well as the upper surface of the plug member 16. Therefore, if the water pressure in the nozzle unit 5 should suddenly reduce below a predetermined value, the spring 26 will force the plug member 16 downwardly until it attains its original position shown in FIG. 1. Since the compression of the piston washer 22 can be varied to adjust the above-mentioned breakaway friction, as discussed above, the amount of pressure in the nozzle unit 5 required to release the plug 16 from the discharge opening 7 can be varied. Although the frictional forces of the sealing rings 17 and 18 acting on the corresponding inner wall portion of the nozzle unit 5 have been neglected in the foregoing example for the convenience of presentation, it is to be understood that they, in fact, should be considered in actual practice.

The head 1 can easily be reassembled after use by simply cutting off the supply of extinguishant, whereby the spring 26 will return the plug member 16 to its initial position shown in FIG. 1. Then a new fusible link 31, along with

lever arms

30a and 30b can be installed in the yoke 28 (or the entire fire detector 12 replaced), and a new fusible nut 25 can be placed in the discharge opening 7, to place the head 1 in condition for further use.

The embodiment of FIG. 2 is similar to the embodiment of FIG. 1, and identical structure will be given the same reference numerals. In the embodiment of FIG. 2, a plug member 40 is provided which has a conical lip position 42 formed at one end thereof which is designed to sealingly engage the corresponding inner surface of the nozzle unit 5 and thus eliminate the need for the sealing rings 17 and 18 of the embodiment of FIG. 1. Also in the embodiment of FIG. 2 the piston washer 22 is of a diameter that is slightly less than the diameter of the corresponding portion of the inner wall of the cylindrical member 8 to define a clearance 44 which permits a slight flow of the water into the interior of the latter member from the chamber 3 and thus eliminate the need for the pressure equalization port 25 of the embodiment of FIG. 1. Otherwise the structure and function of the embodiment of FIG. 2 is identical to that of the embodiment of FIG. 1.

While the two preferred embodiments of the present invention have been shown and described for illustration purposes, it is to be understood that the invention is not limited thereto. Rather, various changes may also be made in the design and arrangement of the structure without departing from the spirit and scope of the invention. For example, the discharge opening 14 formed in the base of the fire detector 12 may be extended to form a tubing so that the remainder of the fire detector 12 may be located at a position remote from the posi-.

tion of the head 1. Moreover, the fire detector 12 need not necessarily .be of the construction shown and described but may be of any other known equivalent fire detector. Furthermore, an on-off fire detector may be utilized so that it can be re-set for repeated operation in contrast to the single operation provided by the detector 12.

Iclaim:

1. A discharge head for use in a fixed fire extinguishing system, said head comprising means defining a chamber having an inlet opening for receiving a supply of fire extinguishant at an inlet pressure, a primary discharge opening for establishing a direct flow path for extinguishant from said head to said fire and a secondary discharge opening; flow preventing means for preventing the flow of extinguishant through said primary discharge opening when said head is in its quiescent state; fire-responsive means for preventing the flow of extinguishant through said secondary discharge opening when said head is in its quiescent state and for allowing flow of extinguishant through said secondary discharge opening in response to a predetermined fire condition; control means responsive to the flow of extinguishant through said secondary discharge opening to actuate said flow preventing means and allow the flow of extinguishant through said primary discharge opening; and means for adjusting the operation of said control means so that said inlet pressure must be at a predetermined value'before said flow preventing means is actuated.

2. The head of claim 1 wherein said fire-responsive means includes a closure member for blocking said secondary discharge opening and a fusible member for holding said closure member in a blocking position.

3. The head of claim 1 wherein said means for defining a chamber also includes means for defining a piston chamber in communication with said secondary discharge opening, said control means including a power piston adapted for movement in said piston chamber and means for connecting said power piston with said flow preventing means.

4. The head of claim 3 wherein said power piston is constructed and arranged with said piston chamber so that the pressure of the extinguishant on both sides of said piston is equalized when the head is in its quiescent state, said flow through said secondary discharge opening causing a relief of the extinguishant pressure on one side of said piston and a resulting movement of said piston in said piston chamber.

5. A discharge head for a fire protection system, comprising a body member having an inlet for a source of fluid under pressure, an outlet for discharging said fluid, a plug member disposed in said body member and adapted for movement in said body member between a first position in which it prevents the discharge of fluid from said outlet and a second position in which it permits the discharge of fluid from said outlet, first means for locking said plug member in said first position and responsive to a predetermined fire condition for releasing said plug member for said movement, second means responsive to a predetermined condition of said system' for preventing said movement despite the release of said plug member by said first means, and

third means to adjust said predetermined condition.

6. The head of claim 5 where said predetermined condition of said system is the absence of a predetermined minimum fluid pressure in said body member.

7. The head of claim 6 wherein said third means is adapted to vary said predetennined minimum fluid pressure.

8. The head of claim 7 further comprising an additional outlet for discharging said fluid, said first means being adapted to permit the discharge of fluid from said additional outlet.

l I I!

Claims

1. A discharge head for use in a fixed fire extinguishing system, said head comprising means defining a chamber having an inlet opening for receiving a supply of fire extinguishant at an inlet pressure, a primary discharge opening for establishing a direct flow path for extinguishant from said head to said fire and a secondary discharge opening; flow preventing means for preventing the flow of extinguishant through said primary discharge opening when said head is in its quiescent state; fireresponsive means for preventing the flow of extinguishant through said secondary discharge opening when said head is in its quiescent state and for allowing flow of extinguishant through said secondary discharge opening in response to a predetermined fire condition; control means responsive to the flow of extinguishant through said secondary discharge opening to actuate said flow preventing means and allow the flow of extinguishant through said primary discharge opening; and means for adjusting the operation of said control means so that said inlet pressure must be at a predetermined value before said flow preventing means is actuated.

5. A discharge head for a fire protection system, comprising a body member having an inlet for a source of fluid under pressure, an outlet for discharging said fluid, a plug member disposed in said body member and adapted for movement in said body member between a first position in which it prevents the discharge of fluid from said outlet and a second position in which it permits the discharge of fluid from said outlet, first means for locking said plug member in said first position and responsive to a predetermined fire condition for releasing said plug member for said movement, second means responsive to a predetermined condition of said system for preventing said movement despite the release of said plug member by said first means, and third means to adjust said predetermined condition.

7. The head of claim 6 wherein said third means is adapted to vary said predetermined minimum fluid pressure.