US3473612A

US3473612A - Fire extinguishing sprinkler system

Info

Publication number: US3473612A
Application number: US594526A
Authority: US
Inventors: Edward J Poitras
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-11-15
Filing date: 1966-11-15
Publication date: 1969-10-21
Anticipated expiration: 1986-10-21

Description

Oct. 21, 1969 a. J. POITRAS 3,473,512

FIRE EXTINGUISHING SPRINKLER SYSTEM Filed Nov. 15, 196 3 Sheets-Sheet 2 a c/ward J P0227425 BY .2 /wf4/@- ATTORNEY.

Oct. 21, 1969 E. J. POITRAS FIRE EXT INGUISHING SPRINKLER SYSTEM 3 Sheets-Sheet 5 Filed NOV. 15, 1966 IVVE/VTOK (Ya ward J P021745 ATTOIQ 'K 3,473,612 FllRE EXTIN GUISHIN G SPRINKLER SYSTEM Edward J. Poitras, 198 Highland St, Holliston, Mass. 01746 Filed Nov. 15, 1966, Ser. No. 594,526 lint. Ci. A62c 35/36, 31/00 US. Cl. 169-11 9 Claims ABSTRACT OF THE DISCLOSURE A fire extinguishing sprinkler system utilizing a supply of liquefied gas fire inhibiting agent as a primary source of extinguishing fluid and a back-up water supply automatically activated after exhaustion of the liquefied gas supply.

This invention relates generally to fire extinguishing systems and more particularly to improvements in automatic fire control apparatus having fluid distributor sprinkling systems.

There exist several types of fire extinguishing sprinkler systems including those commonly referred to as wet type systems in which the distributor pipes are filled at line pressure with either water or a water-antifreeze mixture and the dry pipe systems in which the sealed distributor pipes are filled with air under pressure. However, in all known sprinkler systems, the detection of a fire results in fluid flow between a suitable water source and an opened sprinkler head so as to cause Water discharge therefrom for extinguishing the detected fire.

Although prior fire extinguishing sprinkler systems have been somewhat elfective in the reduction of fire damage, they have sufiered from certain inherent disadvantages. For example, while generally quite useful in the extinguishment of Class A fires, the effectiveness of water as a fire extinguishing agent for Class B and Class C fires is substantially reduced. Also, and of even greater significance, serious water damage frequently accompanies the extinguishrnent of fire by water. Diverse types of automatic control equipment have been developed in attempts to minimize water damage by, for example, automatically shutting off the water supply after extinguishrnent of the fire. However, the very use of water in the first instance necessarily entails risk of water damage to some degree.

The object of this invention, therefore, is to provide an improved fire extinguishing sprinkler system which offers improved protection from fire damage while also minimizing or eliminating the risks of water damage.

A primary feature of this invention is the provision, in a conventional fire extinguishing sprinkler system having a plurality of normally closed sprinkler heads joined by fluid distribution pipes and including automatic fire detectors for opening the nozzles in response to detection of a fire, of an improvement comprising a vessel containing under pressure a liquefied gas fire inhibiting agent and a pressure reducing valve connected between the vessel and the fluid distribution pipes and adapted to discharge thereinto the fire inhibiting gas in a gas or vapor state. This arrangement permits efficient and automatic extinguishment of fires with, for example, the recently developed and highly efiective halogenated vaporizing liquid fire extinguishing agents.

Another feature of the invention is the provision of a fire extinguishing sprinkler system of the above featured type which is additionally coupled to a suitable water source thereby providing the desirable flexibility of a multi-extinguishing agent system.

Another feature of the invention is the provision of a fire extinguishing sprinkler system of the above featured types including an automatically operated valve connected between the water source and the fluid distribution pipes States Patent 0 and a valve control mechanism for opening the valve in response to changes in the quantity of liquefied inhibiting agent contained in the container vessel. In this arrangement, the water source serves as an automatic back-up for the initially utilized liquefied gas inhibiting agent. Thus, if control or extinguishrnent of a detected fire is not completed prior to exhaustion of the liquefied gas supply, the water supply is automatically connected to the distribution system so as to initiate water discharge from the opened nozzles in the conventional manner.

Another feature of the invention is the provision of a fire extinguishing sprinkler system of the above featured types including an automatically operated valve connected between the liquefied gas container vessel and the fluid discharge nozzles, and a valve control mechanism for opening the valve in response to detection of a fire and for closing the valve after a detected fire has been extinguished. This automatic valve closing feature prevents wasteful discharge of the liquefied gas agent after extinguishrnent of a fire and also prevents automatic opening of the water valve which would ultimately occur upon exhaustion of the liquefied gas agent in the event that the system had not been manually deactivated.

Another feature of this invention is the provision of a fire extinguishing sprinkler system of the above featured types wherein the pressure reducing valve connecting the liquefied gas container vessel and distribution pipe system includes a flow pressure regulator which maintains a particular reduced pressure of the fire inhibiting gas within the distribution pipe system. The particular minimum pressure is selected so as to provide an optimum rate of inhibiting gas discharge as determined by the design of the particular nozzles being utilized, the volumes of the protected zones, the material being protected, whether or not the zones are inhabited, etc.

Another feature of this invention is the provision of a fire extinguishing sprinkler system of the above featured type including a static pressure regulating valve connected between the liquefied gas container vessel and the distribution pipe system and adapted to establish therein a steady state pressure substantially greater than the minimum flow pressure established by the flow pressure regulating valve. The establishment of a relatively high steady state gas pressure in the fluid distribution pipes insures a high inhibiting gas discharge rate upon initial opening of a nozzle thereby quickly providing an effective concentration of the extinguishing agent in the fire region. After prompt establishment of the desired concentration, the flow pressure regulating valve maintains in the distribution system a reduced gas pressure and resultant discharge rate suflicient to maintain the desired concentration of extinguishing agent.

Another feature of this invention is the provision of a fire extinguishing sprinkler system of the above featured types including a heat exchange mechanism adapted to furnish at least a portion of the heat energy required during expansion and vaporizing of the gas agent in the pressure regulating valves. This extraneous heat source inhibits inhibiting agent freeze-up which could interrupt flow thereof through the regulator valves.

These and other objects and features of the present invention will become more obvious upon a perusal of the following specification taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a schematic drawing illustrating a preferred sprinkler system embodiment of the invention;

FIG. 2 is a partial schematic view of a modified sprinler system invention embodiment of the invention; and

FIG. 3 is a partial schematic view of another modified sprinkler system invention embodiment of the invention.

Referring now to FIG. 1 there is shown the fluid distribution pipe system 11 connected between the fluid discharge nozzles 12 and the pressure tight container vessel 13. Contained under pressure within the vessel 13 is a suitable liquefied gas extinguishing agent 14. A particularly desirable liquefied gas agent is Freon PE 1301 (CBrF which is marketed by the Du Pont Co. and has a vapor pressure of about 200 lbs. per sq. in. absolute at about 65 F. Connecting the container vessel 13 to the fluid distribution system 11 is the pressure reducing valve assembly 15 including the circular valve plate 16 and the cup shaped cover plate 17 The container vessel 13, the valve plate 16 and the cover plate 17 are pressure sealed along the annular connecting flanges 18.

Drilled into the valve plate 16 is the valve opening 21 having the counterbore 22 which provides a valve seat for the flow regulator valve 23. Control of the valve 23 is provided by the differential pressure regulator 24 mounted on the cover plate 17. The regulator housing 25 is divided into the low pressure chamber 26 and the high pressure chamber 27 by the flexible diaphragm 28. Positioned in the low pressure chamber 26 is the reference spring 29 for exerting a downward force on the flexible diaphragm 28 which is operatively connected also to the valve 23 by the valve stem 31 extending through a bearing aperture in the cover plate 17. The orifice 32 in the regulator housing 25 provides gas communication between atmosphere and the low pressure chamber 26 while the orifice 33 in the cover plate 17 provides gas communication between the high pressure chamber 27 and the valve chamber 34.

Also drilled in the valve plate 16 is the restricted valve opening 41 having the conically shaped counterbore 42 which forms a valve seat for the static pressure valve 43. Control of the valve 43 is provided by the differential pressure regulator 44 mounted on the cover plate 17. The regulator housing 45 is divided into the low pressure chamber 46 and the high pressure chamber 47 by the flexible diaphragm 48. Positioned in the low pressure chamber 46 is the reference spring 49 for exerting a downward force on the flexible diaphragm 48 which is operatively connected also to the valve 43 by the valve stem 51 extending through a bearing aperture in the cover plate 17. The orifice 52 in the regulator housing 45 permits gas communication between atmosphere and the low pressure chamber 46 while the orifice 53 in the cover plate 17 permits gas communication between the high pressure chamber 47 and the valve chamber 34.

Threadedly attached to the cover plate 17 is the fluid distribution pipe 11a which provides fluid communication between the valve chamber 34 and the main fluid distribution system 11. Inserted into the distribution pipe 11a is the flow meter 61 and the manually operated valve 62. The flow meter 61 is coupled by the electrical leads 63 to a suitable signaling device (not shown).

Also connected to the fluid distribution system 11 by the auxiliary valve assembly 71 is the Water supply pipe 72 which is in turn connected to a suitable source of water under pressure (not shown) by the manually operated valve 73. The valve assembly 71 includes the valve body 74 which defines the valve opening 75 and is closed by the cover plate 76. Seated in the valve opening 75 is the auxiliary valve 77 operatively secured to the valve stem 78 which extends through a sealed bearing aperture in the cover plate 76. Control of the valve 77 is provided by the control mechanism 81 including the flexible diaphragm 85 which divides the control housing 82 into the reference chamber 83 vented by the orifice 83a and the control chamber 84 and is attached to the valve stem 78. Mounted in the reference chamber 83 is the reference spring 86 which exerts an upwardly directed, valve opening force on the flexible diaphragm 85. The control pipe 87 and associated three-way valve 88 permit fluid communication between the interior of the container vessel 13 and the control chamber 84.

Operation of the invention embodiment shown in FIG. 1 occurs in the following manner. During normal conditions the

manual valves

62 and 73 are maintained in an open position and the conventional valved sprinkler nozzles 12, typically distributed throughout the various fire protected zones, are maintained in closed position by the fusible elements 89 so as to seal the fluid distribution pipe system 11 from the atmosphere. With the three-way valve 88 in the position shown, the substantial vapor pressure above the liquefied extinguishing agent 14 will also exist in the control chamber 84. The force exerted on the flexible diaphragm by this pressure is suflicient to overcome the biasing force of the reference spring 86 and maintain the valve 77 in the closed position thereby isolating the fluid distribution lines 11 from the water source 72. At this time the distribution lines 11 are filled with either vaporous or gaseous extinguishing agent 14 which has passed through the static valve opening 41. The static pressure of the extinguishing agent in the distribution lines 11 is determined by the regulator 44 which is so designed that the force exerted against the flexible membrane 48 by a desired static pressure in the high pressure chamber 47 will overcome the force applied by the reference spring 49 to cause closing of the static valve 43.

The heat generated by a fire in one or more protected zones will induce fusing of the proximate fuse elements 89 and cause opening of their associated nozzle valves 12. The relatively high gas pressure in the distribution lines 11 will initially induce a relatively high rate of extinguishing agent discharge through the opened nozzles 12 to quickly permeate the zone or zones affected by the fire. The resultant decrease in gas pressure within the distribution system 11 and communicating high pressure chamber 47 will permit the reference spring 49 to open the static valve 43. However. the limited flow rate possible through the restricted valve opening 41 will be insufficient to maintain static pressure and, accordingly, the distribution system pressure will fall until a preselected minimum pressure is achieved. This minimum pressure is selected to provide through the open nozzles 12 a fire inhibiting agent discharge rate sufficient to maintain a desired concentration of the agent in the protected zones. Obviously, the optimum pressure will depend upon the structural design of the particular nozzles utilized, the volumes of the protected zones, the material being protected, etc. At this preselected optimum pressure, the force exerted against the flexible diaphragm 28 will be insuflicient to overcome the force exerted by the reference spring 29 and the flow valve 23 will open. The larger flow valve opening 21 will permit sufilcient flow of extinguishing agent 14 to maintain within the distribution lines 11 the desired minimum pressure.

Responsive to the flow in distribution pipe 110, the flow meter 61 will provide an alarm signal that a tire exists. Thereafter, an attendant signaled by the alarm can stop discharge of the extinguishing agent by closing the manual valve 62 after observing that the fire has been extinguished. If the valve 62 is not closed the flow of extinguishing agent 14 will continue until the supply within the container vessel 13 is exhausted at which time the water supply 72 will be connected automatically to the distribution system 11 in the following manner. The pressure decrease within the vessel 13 resulting from exhaustion of the liquefied agent 14 will be transmitted to the control chamber 84. There, the force exerted by this reduced pressure against the flexible diaphragm 85 will be insufficient to overcome the force exerted by the reference spring 86 and the valve 77 will open and water will flow from the source 72 for discharge through the opened nozzles 12.

Thus, the invention permits automatic control of fires with extremely effective and harmless vaporizing liquid agents such as Freon PE 1301 in addition to providing the safety precaution of a water back-up for occasions in which the inhibiting agent is exhausted prior to extinguishment of the fire. In this regard, it should be noted that an attendant if he so desires can also combine the vaporous inhibiting agent with the water for discharge through the nozzles 12. This is accomplished by manually actuating the three-Way valve 88 so as to connect the control chamber 84 with the vent opening 90 prior to exhaustion of the liquid 14. The resultant pressure rise in the control chamber 84 allows opening of the valve 77 and flow of water into the distribution system 11.

Additional elements shown in FIG. 1 are the tank 91 filled with a suitable heat exchange fluid 92 such as Water and enclosing the container vessel 13 and the bosses 93 attached to the underside of the valve plate 16 and surrounding the valve openings 21 and 41. As described below, these elements inhibit within the valve openings 21 and 41 possible freezing of the fire inhibiting agent 14 which could interrupt flow thereof into the distribution system 11. With relatively high discharge rates through the

regulator valves

23 and 43, the substantial heat energy required for providing the latent heat of vaporization and for reducing the pressure of the liquid agent can cause freezing thereof. Since uninterrupted flow of the fire inhibiting agent is critical in fire fighting applications, protection against freezeup is an important feature of the invention.

The cylindrical bosses 93 enlarge the surface upon which condensation of the surrounding saturated inhibiting agent 14 can occur and latent heat provided by condensation helps prevent freezing of the escaping vapor. The cold condensed liquid then flows down the surfaces of the cylindrical bosses 93 and drops into liquefied agent 14. Simultaneously however, heat is transferred to the liquefied agent 14 through the walls of the container vessel 13 from the heat exchange fluid 92. Thus, an overall heat transfer mechanism is provided which furnishes the heat required for vaporization and expansion of the escaping agent 14 thereby preventing freezing thereof.

Referring now to FIG. 2, there is shown a modified distribution system 94 which can be used in place of the distribution system 11 shown in FIG. 1. Each branch 95 of the distribution system 94 has an isolating valve 96 positioned between the fire extinguishing fluid supplies (shown in FIG. 1) and the branchs individual nozzles 97. Located in the same zones serviced by the nozzles 97 are the plurality of normally closed thermostats 98 which are adapted to selectively open at a predetermined above normal environmental temperature and to close below said above normal temperature. The thermostats 98 in each branch 95 are connected in series with a suitable power source 100 and the actuating solenoid 99 of the branchs normally open isolating valve 96 Under normal conditions the thermostats 98 are closed to energize the solenoids 99 and actuate the normally open valves 96 to a closed position. However, the heat generated by a fire in a protected zone will open the approximately positioned thermostat 98 so as to interrupt current flow through the series connected solenoid 99 and open the associated isolating valve 96. The distribution of the fire inhibiting fluid will then proceed in the manner described above in connection with FIG. 1 except that after extinguishment of the fire and suflicient cooling of the fire zone the affected thermostats 98 will again close to induce current flow through the connected solenoid 99 and resultant closing of the associated valve 96. This isolates the open branch nozzles 97 and prevents further discharge of the extinguishing agent 14. Thus, the embodiment of FIG. 2 automatically stops fluid extinguishing fluid discharge and prevents undesirable opening of the water supply valve 77 in the event that the fire has been extinguished by the fire inhibiting agent 14 prior to exhaustion thereof.

FIG. 3 illustrates another distribution system embodiment of the invention wherein the principal branch network 105 is joined to the secondary network 106 by the check valve 107. The branch 105 is connected by the pipe 108 to a source of liquefied extinguishing gas such as that shown in FIG. 1 and the network 106 is connected by the valve assembly 109 to the Water supply 110. Included in the valve assembly 109 is the valve housing 111 having the cover plate 112 and forming a valve seat 113 for the valve head 114. The inner walls of the control housing 115 establish a bearing surface for the guide plate 116 which is operatively attached to the valve head 114 by the valve stem 117. Urging the valve 114 toward an open position is the reference spring 118 positioned between the cover plate 112 and the guide plate 116.

During normal operation a given pressure of the gas extinguishing agent is maintained in the principal branch as in the embodiments shown in FIGS. 1 and 2 and the same static pressure exists in the secondary network 106 because of the restricted gas flow provided by the throttle valve 121 which is connected in parallel with the check valve 107. The force exerted by this static gas pressure against the upper surface of the valve head 114 overcomes the forces applied by the spring 118 against the plate 116 and by the water pressure against the valve head 114 to maintain the valve in a closed position. Upon the occurrence of a fire in a zone protected by the principal branch 105, opening of the proximate nozzle valves 122 will result in discharge of a vaporized extinguishing agent as described above. If the fire is not extinguished prior to exhaustion of the liquefied gas supply there will occur in the branch 105 a pressure drop which will induce gas flow from the secondary network 106 through the check valve 107. This discharge of gas from the secondary network 106 will lower the pressure in the valve housing 111 and accordingly reduce the force exerted against the valve head 114. At some particular reduced pressure the reference spring 118 will open the valve 114 and Water will be supplied from the source to the secondary network 106, through the check valve 107 and into branch network 105 for discharge through the opened nozzle valves 122.

Conversely, upon opening of one or more nozzle valves 123 in response to a fire in a zone protected by the secondary network 106, the gas pressure therein will be immediately discharged since gas from the liquefied gas supply cannot pass through the check valve 107 and the gas flow through the throttle valve 121 is insufficient to maintain pressure. Thus, the valve 114 will immediately open and water from the source 110 will be supplied for discharge through the open nozzle valves 123.

The embodiment of FIG. 3 permits segregation of the fire protected region into principal zones protected by the liquefied gas extinguishing agent system with a Water supply back-up and secondary zones protected only by the water supply. Such a system has particular utility for structures comprised by individual wings of varied use. For example, the principal branch 105 could be used for building zones which house extremely valuable equipment such as electronic instruments, particularly water sensitive materials such as paper products, combustible substances for which Water is a generally ineffective fire extinguishing agent such as liquid fuels, etc. Conversely, the secondary network 26 could be used to protect building zones which house less valuable materials or those relatively unsusceptible to water damage. In this way the required capacity and cost of the relatively expensive liquefied gas source can be reduced.

Although this disclosure presents preferred embodiments, it will be obvious that various changes could be made in the individual components without affecting the overall operation of the invention. For example, the signal generated by the flow meter 61 could be utilized to deactivate blower systems (not shown) which might undesirably disperse the discharging gaseous extinguishing agent. Also, other conventional heat responsive release valves could be substituted for the fusible type shown or open valves could be utilized in conjunction with suitable isolating branch valves. Similarly, control devices such as temperature sensors or liquid level indicators could be substituted for the pressure responsive control unit 81 or other liquefied gas extinguishing agents such as carbon dioxide, nitrogen, other Freons, etc., could be utilized. It should be noted in this regard, however, that because of several inherent characteristics, Freon PE 1301 is a particularly desirable agent for this application. Being heavier than air, FE 1301 will conveniently descend upon a fire which is typically at a level below the discharging sprinkler nozzle. This is particularly important where a protected zone is greatly congested so that a shrouded fire might not be easily reached by discharging water but would be quickly encountered by the more fluid gaseous extinguishing agent. Also, in addition to being extremely effective against Class B and C fires, PE 1301 exhibits a negligible toxicity and an excellent chemical stability rendering it satisfactory for use in practically all fire protection applications and with practically all types of materials employed in fire extinguishing equipment.

Thus, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A fire extinguishing system apparatus including a plurality of distributed and normally closed fluid discharge nozzle means, a closed fluid distribution means connecting said nozzle means and adapted to supply a fire extinguishing fluid thereto, and automatic fire detection means adapted to sense the presence of fire and to open said nozzles in response thereto; wherein the improvement comprises a cotnainer means containing under pressure a liquefied fire inhibiting gas, pressure reducing valve means connecting said container means to said fluid distribution means and adapted to discharge said fire inhibiting gas in a gas or vapor state from said container means into said fluid distribution means, a water source, an auxiliary valve connecting said fluid distribution means to said water source and wherein said fluid distribution means comprises a principal fluid distribution network comprising a portion of said nozzle means and connected to said container means and a secondary fluid distribution network comprising a portion of said nozzle means and connected to said water source, and including check valve means connecting said principal and secondary networks and adapted to permit fluid flow only in the direction from said secondary to said primary network.

2. A fire extinguishing system apparatus according to claim 1 wherein said pressure reducing valve means further comprises a static pressure regulation means adapted under normal conditions with said nozzle means closed to maintain said fire inhibiting gas in said fluid distribution means at a given pressure substantially greater than said minimum pressure.

3. A fire extinguishing system apparatus according to claim 1 including a valve actuator for actuating said auxiliary valve, and valve actuator control means adapted to monitor the quantity of liquefied fire inhibiting gas in said container means and to supply a control signal to said valve actuator in response thereto.

4. A fire extinguishing system apparatus according to claim 3 wherein said valve actuator control means comprises a pressure responsive means adapted to sense pressure variations resulting from changes in the quantity of liquefied fire inhibiting gas contained by said container means.

5. A fire extinguishing system apparatus according to claim 4 wherein said valve actuator control means is adapted to produce opening of said auxiliary valve in response to a substantial absence of liquefied fire inhibiting gas in said container means, and including manually operated means for actuating said valve actuator control means to produce opening of said auxiliary valve.

6. A fire extinguishing system apparatus according to claim 5 including isolating valve means connected between said container means and said nozzle means, and automatic control means adapted to open said isolating valve means in response to detection of fire by said fire detection means and to close said isolating valve means in response to the absence of fire detection by said fire detection means.

7. A fire extinguishing system apparatus according to claim 6 wherein said pressure reducing valve means further comprises a static pressure regulation means adapted under static conditions with said nozzle means closed to maintain said fire inhibiting gas in said fluid distribution means at a given pressure substantially greater than said minimum pressure.

8. A fire extinguishing system apparatus according to claim 1 including throttle valve means connected in parallel with said check valve means and adapted to permit a restricted gas flow from said principal network to said secondary network.

9. A fire extinguishing system apparatus according to claim 8 wherein said auxiliary valve is adapted to open in response to a pressure reduction in said secondary network.

References Cited UNITED STATES PATENTS Re. 20,624 1/1938 White 62-50 1,247,580 11/1917 Seeger 169-7 1,969,869 8/1934 Allen et al. 169-11 2,544,016 3/1951 Getz 169-11 2,713,916 7/1955 Muckenfuss 169-17 3,052,304 9/1962 Williamson et al. 169-11 2,177,581 10/1939 Purviance 169-11 FOREIGN PATENTS 18,903 11/1899 Great Britain. 219,871 8/ 1924 Great Britain.

EVERETT W. KIRBY, Primary Examiner US. Cl. X.R. 169-7, 14, 17, 20