US3616860A - Quick opening device for dry-pipe valves of automatic sprinkler systems - Google Patents

Abstract

A component for automatic sprinkler systems employed for fire protection is provided which is useful in dry-pipe systems to cause rapid opening of the dry-pipe valve of such systems in response to a slight but rapid decrease of air pressure in the sprinkler piping network attendant upon opening of a sprinkler head. Slow decreases in such pressure in relation to atmospheric pressure are offset by an atmospheric bleed valve, a readily accessible adjustment for altering and visibly indicating the trip-off pressure is provided, and provision is made for either electrical or pneumatic operation.

Description

United States Patent Charles F. Willms Rutherford, NJ. 863,985

Oct. 6, 1969 Nov. 2, 1971 Norris Industries, Inc. Los Angeles, Calif.

Inventor Appl. No. Filed Patented Assignee QUICK OPENING DEVICE FOR DRY-PIPE VALVES OFAUTOMATIC SPRINKLER SYSTEMS 4 Claims, 5 Drawing Figs.

U.S. Cl 169/17, 169/19 Int. Cl A62c 35/00 Field of Search 169/ 19-22, 17

References Cited UNITED STATES PATENTS 712,682 11/1902 Jefferson 169/20 1,050,036 l/l9l3 Mueller et al 169/19 1,491,301 4/1924 Grafflin 169/20 1,900,300 3/1933 Paden et al. 169/19 X 2,591,959 4/1952 McRae 169/20 Primary Examiner-Lloyd L. King Attorney-Huebner & Worrel ABSTRACT: A component for automatic sprinkler systems employed for fire protection is provided which is useful in drypipe systems to cause rapid opening of the dry-pipe valve of such systems in response to a slight but rapid decrease of air pressure in the sprinkler piping network attendant upon opening of a sprinkler head. Slow decreases in such pressure in relation to atmospheric pressure are offset by an atmospheric bleed valve, a readily accessible adjustment for altering and visibly indicating the trip-off pressure is provided, and provision is made for either electrical or pneumatic operation.

AIR SIDE OF SYSTEM i were: SUPFLY PATENTEnuuv 2 I971 3,616,860

sum 10F 2 TO WATER MO OR AIR SIDE OFSPRINKLER SYSTEM H 2 .On/E/vro/q i 64024.55 1 W/ZLMS QUICK OPENING DEVICE FOR DRY-PIPE VALVES OF AUTOMATIC SPRINKLER SYSTEMS BACKGROUND OF THE INVENTION 1. B. Field of the Invention Automatic sprinkler systems embody a network of overhead piping extending throughout a building or area and provided at spaced intervals with sprinkler heads, which are essentially heat-responsive valves which open under the influence of a local conflagration to discharge water from the piping over the area covered by the opened sprinkler or sprinklers.

In locations in which there is no exposure of the piping of such systems to freezing temperatures, a wet-pipe system may be installed. In such a system, water is held in the piping throughout the system, and immediately discharged whenever a sprinkler head opens.

However, in locations in which the piping is likely to be exposed to freezing temperatures, a dry-pipe system must be installed. In such a system, air is held in the piping throughout the network of piping. A main control valve, known as a drypipe valve, which is located in an area not exposed to freezing temperatures, opens in response to a drop in air pressure in the piping network occasioned by the opening of a sprinkler head, allowing water to flow into the piping network and discharge through the open sprinkler head or heads.

The interval between the opening of a sprinkler head of such a dry-pipe system and the discharge of water from it necessarily lengthens as the size of the system increases, because the rate at which air can be discharged through an open sprinkler head is limited and the relationship of the volume of air so discharged to the total volume of air in the piping network becomes smaller as that total volume increases.

Among the standards agreed upon for automatic sprinkler systems is one fixing a limit on the interval between the opening of a sprinkler head and the discharge of water from it; it being required to be short enough to afford a reasonable assurance that a fire will not intensify or spread beyond control. In order to comply with this interval standard, it has been necessary in large dry-pipe systems, to provide devices for causing the dry-pipe valve to open in response to the opening of a sprinkler head, at an earlier point in time than it would in the absence thereof. Such devices are known as quick-opening devices, exhausters, or accelerators, and it is to the improvement of this class of devices that the present invention is directed.

2. Description of the Prior Art Disclosures of various types of dry-pipe valves and quickopening devices are compiled in Chapter IX of the Fire Protection Handbook," 12th Edition, compiled by the National Fire Protection Association and published by The Riverside Press, Cambridge, Massachusetts, 1962.

A principal type of dry-pipe valve, as disclosed in the U.S. Pat. No. 2,667,934 of Rowley dated Feb. 2nd, 1954, comprises an intermediate chamber disposed between an inlet chamber connected to the water main and an outlet chamber connected to the sprinkler piping network; a normally closed valve being disposed between the inlet and outlet chambers. This valve is prevented from opening as long as the pressure of the air in the sprinkler piping network, which is in excess of the atmospheric pressure, exceeds a predetermined magnitude. Even in the absence of any quickopening device, the water supply pressure will cause the valve to open if the pressure of the air in the sprinkler piping network falls below a critical point.

Various types of devices have been provided for expediting the opening of such dry-pipe valves upon a decrease in the air pressure in the sprinkler piping network to a predetermined point higher than the point at which such opening would occur were such a device not provided. One type of such device responds to a decrease in pressure in the sprinkler piping network to exhaust air therefrom into the intermediate chamber of the dry-pipe valve, thus rapidly equalizing the pressure above and below a diaphragm forming a part of the valve between the inlet and outlet chambers and permitting the water pressure to open the valve.

Such devices must, however, be capable of discriminating between rapid pressure drops in the sprinkler piping network resulting from opening of a sprinkler head and requiring prompt opening of the dry-pipe valve, and slow pressure drops resulting from lowering of air temperature in the piping network, etc., which must not be allowed to cause opening of the dry-pipe valve. For this reason, prior devices of this type have included dual internal chambers communicating through a restricted orifice; one such chamber being connected to the sprinkler piping network, and the arrangement being such that the device operates only when the pressure in the latter chamber falls below the pressure in the other chamber by a predetermined amount due to inability of the restricted orifice to effect sufficiently rapid equalization.

The restricted orifices of such devices are subject to clogging, allowing them to cause opening of the dry-pipe valve in response to even slow drops in the pressure of the air in the sprinkler piping network which, of course, is highly undesirable. Furthermore, the point at which such devices will cause opening of the dry-pipe valve can be changed only by adjustment of the restricted orifice.

SUMMARY OF THE INVENTION In contrast to the prior devices referred to above, which rely upon sensing of differences between the ambient pressure in a secondary chamber communicating unrestrictedly with the piping network and the pressure retained in a primary chamber communicating with the piping network through a restricted orifice to cause opening of the dry-pipe valve, the device of the present invention senses differences between the ambient pressure in a secondary chamber communicating unrestrictedly with the piping network and the pressure in a primary chamber communicating through a restricted orifice with the atmosphere instead of with the secondary chamber; the restricted orifice being provided so that slow decreases in pressure in the piping network may be offset by the flow of air through the restricted orifice, while rapid decreases in pressure in the piping system will produce a. partial vacuum in the primary chamber the volume of which; varies inversely with respect to that of the secondary chamber.

This makes it possible to dispose the restricted orifice between the interior and exterior of the device instead of between two chambers within the device, thus reducing the likelihood of clogging of the orifice and rendering it more easily accessible for cleaning or replacement in the event such clogging should occur.

The primary chamber may be connected directly to a conventional vacuum responsive electrical switch adapted for connection to a solenoid valve so that, upon the occurrence of a partial vacuum in the primary chamber, the solenoid valve will open and admit fluid under pressure to the split seat of the dry-pipe valve of a dry-pipe sprinkler system, thus causing the dry-pipe valve to open and admit water under pressure to the sprinkler pipe network much sooner than it would open in response to an air pressure drop in that network.

Alternatively, the primary chamber may be connected to a pilot valve operating mechanism so that, upon the occurrence of a partial vacuum in the primary chamber, a valve will be opened to admit fluid under pressure to the split seat of such a dry-pipe valve to produce the same result.

The point at which the device of the present invention will cause opening of the dry-pipe valve may readily be altered without changing the rate of flow of air through the restricted orifice, and that point is visibly indicated by a scale exteriorly of the device. Such adjustment is effected by varying the compression of a spring counterbalancing the air pressure in the sprinkler piping network.

Brief Description of the Drawings FIG. 1 is a view partially in section of an embodiment of the present invention designed for electrical control of the drypipe valve of an automatic sprinkler system, illustrating diagrammatically the connection of the device to such a system;

FIG. 2 is a detail sectional view taken on the line 2-2 of FIG. 1, showing the construction of the device supplying the restricted orifice;

FIG. 3 is a circuit diagram showing the electrical connections between the device of the present invention and a solenoid valve for controlling the dry-pipe valve;

FIG. 4 is an illustration, partly in section, of an embodiment of the present invention designed for fluid pressure operation, illustrating diagrammatically the connection between such a device and a dry-pipe automatic sprinkler system; and

FIG. 5 is a detail sectional view taken on the line 55 of FIG. 4, showing a detail of the structure of the device of FIG. 4.

.Description of the Preferred Embodiments Referring now to the accompanying drawings and particularly to FIGS. 1 and 4 thereof, there is shown diagrammatically a conventional dry-pipe valve M) which, for example, is preferably of the construction illustrated in the U.S. Pat. No. 2,667,934, of Rowley although certain of the other types of drypipe valves illustrated in the Fire Protection Handbook referred to above may be substituted therefor. The valve has its inlet side connected by apipe 12 to a water supply main I4 through a manually operable valve 16 and its outlet side connected by apipe 18 to the piping network of a conventionalautomatic sprinkling system 20 which, when thevalve 10 is closed, conventionally is filled with air under higher than atmospheric pressure.

Thevalve 10, as shown in the Rowley U.S. Pat. No. 2,667,934 referred to above, comprises a clapper structure within which is a chamber designated by the reference numeral 53 in said patent, which is known at the split seat of the dry-pipe valve and which is normally in communication with the atmosphere through apipe 22 and a drain clapper valve 24 corresponding to the drain clapper valve designated 93 in said patent; this arrangement being such that when fluid under pressure is admitted to thepipe 22, it will effect automatic closure of the drain clapper valve 24 and cause fluid to pass under pressure into the dry-pipe valves split seat" which is the clapper valve chamber designated 53 in said patent, thus causing quick opening of the dry-pipe valve 10.

Apipe 25 connects thepipe 22 with a water motor operating an alarm for signalling the opening of the dry-pipe valve 10 and apipe 26 connects thepipe 25 with theinlet pipe 12 through a manuallyoperable valve 28 which may be opened at any time to test the operability of the alarm.

The elements thus far described in detail are conventional elements of dry-pipe automatic sprinkler systems and form no part of the present invention.

The present invention provides, for incorporation into such a system, a device which is responsive to a slight but rapid decrease of air pressure in the sprinkler piping network, such as the pressure decrease attendant upon opening of a sprinkler head, to cause an immediate admission of fluid into thepipe 22 and consequent rapid opening of the dry-pipe valve 110.

The form of the device of the present invention illustrated in FIGS. 1 to 3, which is designed for electrical operation, comprises a cylindrical body formed by an upper member 30 and alower member 32 secured together bybolts 34 passing throughflanges 36 and 38 on the upper and lower cylindrical members respectively. The upper andlower members 30 and 32 are provided with internal cylindrical cavities defining acompartment 37 which is divided into primary andsecondary chambers 39 and 40 by piston means comprising aflexible diaphragm 42 the edge of which is retained between theflanges 36 and 38, and a piston 44 to which thediaphragm 42 is centrally secured by adisk 46 andbolt 48.

The piston means 42, 44 is movable longitudinally within thecompartment 37 to inversely vary the relative volumes of thechambers 39 and 40, that is, to increase the volume of theprimary chamber 39 as the volume of thesecondary chamber 40 is decreased, and vice versa, by means comprising a piston rod 50 extending through acylindrical opening 52 in the upper member 30 and provided with an O-ring 54 which maintains an hermetic seal between the piston rod 50 and the member 30. Acylindrical spring housing 56 is secured to the upper member 30 bybolts 58, and secured to the upper end of the piston rod 50 is aspring seat 60 guided for longitudinal movement within thehousing 56 by apin 62 extending from theseat 60 into aslot 64 in thehousing 56. Aspring 66 is compressed between thespring seat 60 and anupper spring seat 68 which, likewise is guided for longitudinal movement within thehousing 56 by a pin 70 extending from theupper spring seat 68 into theslot 64.

Means are provided for adjusting the compression of thespring 66 by moving theupper spring seat 68 between the position in which it is shown in full lines and the position in which it is shown in dotted lines. This means comprises a threadedrod 72 the threads of which mate with internal threads in acentral aperture 73 in theupper spring seat 68 and the opposite end of which is rotatably mounted in anend closure 74 secured to an end of thehousing 56 bypins 76. The outside end of the threadedrod 72 is provided with anoncircular recess 78 into which a mating tool may be inserted to rotate therod 72 in one direction or the other to alter the compression of thespring 66, and aprotective cap 80 is frictionally fitted over the end of thehousing 56.

Thelower chamber 40 is provided with anopening 82 which is threaded for connection to apipe 34 extending from thepipe 18 connected to the piping network of the automatic sprinkler system, and a gauge 86 preferably is connected to the pipe 84 for indicating the ambient pressure in the piping network and thechamber 40 which, as previously mentioned, is conventionally maintained above atmospheric pressure. The compression adjustment of thespring 66 is adjusted so that it approximately balances this pressure and thus maintains the piston means 42, 44 at a position intermediate between its extreme positions within thecompartment 37.

Thechamber 39 normally is maintained at atmospheric pressure; a restricted orifice between it and the atmosphere being provided to restore the pressure therein to atmospheric pressure in the event that relatively slow changes in the air pressure in the network of sprinkler piping, such as, for instance, pressure changes arising from slowly rising or falling temperatures, cause movement of the piston means 42, 44 in either direction. Such a restricted orifice is provided by a compensating vent fitting 90 threaded upon asleeve 92 which in turn is threaded into the enlarged upper end of apassage 94 communicating with thechamber 39. This compensating vent fitting, as shown in detail in FIG. 2, may be, for example, a conventional component such as is manufactured by Automatic Sprinkler Corporation of America for use in thermopneumatic systems, and in this form comprises essentially a ho]-low body member 94 within which a small mass ofkapok 96 may be compressed betweendisks 97 and 98 by adjustment of a threadedsleeve 99. Such vents are calibrated in the factory by compressing the kapok in the vent body by screwing down the threadedsleeve 99; the rating being stamped on the vent at the time of calibration and not usually altered thereafter. The interior of the compensating vent fitting communicates at one end with theopening 94 intochamber 39 and at the other end, through anaperture 100, with the atmosphere.

Means are provided for actuating an electrical switch whenever the pressure in thechamber 39 falls below atmospheric pressure by a predetermined amount in response to a drop in the pressure inchamber 40 more rapid than can be offset by the induction of air from the atmosphere through the restricted orifice means comprising the compensating vent fitting 90; This means comprises a threaded opening I02 through the wall of the member 30 into thechamber 39 into which opening is threaded one end of a pipe fitting 104 communicating with abellows assembly 106 contractable in response to a drop in pressure in thechamber 39 to cause closure of anelectrical switch 108 of conventional construction.

Means are provided for automatically admitting fluid pressure to thepipe 22 to cause opening of the dry-pipe valve immediately upon the closing of theswitch 100. As shown in FIG. 3, closure ofswitch 108 completes the circuit from a source ofelectrical power 110 to asolenoid 112 which, when thus energized, opens a valve 114. The valve 114 is disposed in apipe 116 communicating with a source of fluid pressure such as, preferably, the water pressure supplied through thepipe 12 to the inlet side of the dry-pipe valve 10, although the air pressure in the sprinkler piping network of the automatic sprinkler system may be utilized as such a source of fluid pressure or an entirely independent source of fluid pressure could be employed.

In the operation of the device of the present invention, slow changes in the air pressure in the sprinkler piping network of the automatic sprinkler system are offset by the induction or expulsion of air from thechamber 39 through the compensating vent fitting 90 without effecting closure of theswitch 108. However, in the event of a rapid drop of air pressure in the sprinkler piping network, such as the pressure drop produced by the opening of a thermally responsive valve of a sprinkler head, the pressure in thechamber 40 drops rapidly and the piston means 42, 44 moves downwardly, producing a vacuum in thechamber 39 too rapidly to permit it to be offset by the induction of air through the compensatingvent 90. The production of a vacuum in thechamber 39 in this manner contracts thebellows assembly 106 causing a closure of the electrical switch 1023, energization of thesolenoid 112 and opening of the valve 114, admitting fluid pressure through thepipe 116 to apipe 22. The drain clapper valve 24 closes automatically,'as described in Rowley, U.S. Pat. No. 2,667,934, and the fluid pressure thereby created in thepipe 22 enters the chamber designated 53 in said patent, causing immediate opening of the dry-pipe valve 10.

The form of the device of the present invention illustrated in FIGS. 4 and 5, which is designed for exclusively fluid pressure operation without electrical elements, comprises a cylindrical body formed by anupper member 130 and alower member 132 secured together bybolts 134 passing through flanges 136 and 138 on the upper and lower cylindrical members respectively. The upper andlower members 130 and 132 are provided with internal cylindrical cavities defining acompartment 137 which is divided into primary andsecondary chambers 139 and 140 by piston means comprising aflexible diaphragm 142 the edge of which is retained between the flanges 136 and 138, and a piston 144.

The piston means 142, 144 is movable longitudinally within thecompartment 137 to inversely vary the relative volumes of thechambers 139 and 140; that is, to increase the volume of theprimary chamber 139 as the volume of the secondary chamber 140 is decreased, and vice versa, by means comprising apiston rod 150 extending through acylindrical opening 152 in theupper member 130 and provided with an O-ring 154 which maintains an hermetic seal between thepiston rod 150 and themember 130. Acylindrical spring housing 156 is secured to theupper member 130 byscrews 158, and in engagement with the upper end of thepiston rod 150 is aspring seat 160 guided for longitudinal movement within thehousing 156 by apin 162 extending from theseat 160 into a slot 164 in thehousing 156. Aspring 166 is compressed between thespring seat 160 and anupper spring seat 168 which, likewise, is guided for longitudinal movement within thehousing 156 by a pin 170 extending from theupper spring seat 168 into the slot 164.

Means are provided for adjusting the compression of thespring 166 by moving theupper spring seat 168 between the position in which it is shown in full lines and position in which it is shown in dotted lines. This means comprises a threadedrod 172 the threads of which mate with internal threads in acentral aperture 173 in the upper spring seat and the opposite end of which is devoid of threads and is rotatably mounted in anend closure 174 secured to an end of thehousing 156 bypins 176. The outside end of the threadedrod 172 is provided with a noncircular recess into which a mating tool may be inserted to rotate the rod 1.72 in one direction or the other to alter the compression of thespring 166. A protective cap is frictionally titted over the end of thehousing 156.

The secondary chamber 140 is provided with anopening 182 which is threaded for connection to apipe 104 extending from thepipe 18 connected to the piping network of the automatic sprinkler system, and a gauge 196 preferably is connected to thepipe 184 for indicating the ambient pressure in the piping network and the secondary chamber 140 which, as previously mentioned, is conventionally maintained above atmospheric pressure. The compression adjustment of thespring 166 is adjusted so that it approximately balances this pressure and thus maintains the piston means 142, 144 at a position intermediate between its extreme positions within thecompartment 137.

Theprimary chamber 139 is normally maintained at atmospheric pressure communicating with the atmosphere through a restricted orifice, so that the pressure therein is restored to atmospheric pressure in the event that relatively slow changes in the air pressure in the network of sprinkler piping, such as, for instance, pressure changes arising from slowly rising or falling temperatures, cause movement of the piston means 142, 144 in either direction.

In the embodiment of the invention shown in FIG. 4, such a restricted orifice is provided by a compensating vent fitting 90 shown in detail in FIG. 2 and described in connection with the embodiment illustrated in FIGS. 1 to 3, this fitting, in the embodiment illustrated in FIG. 4, being threaded onto an externally threadedsleeve 191 which is in turn threaded into anopening 193 in amember 195 defining acavity 197 communicating with theprimary chamber 139 via atube 199 the ends of which are threaded into openings in "theprimary chamber 139 and the wall of thecavity 197, respectively.

Means are provided for actuating a valve to permit fluid under pressure to pass from a source of fluid pressure to the split seat of the dry-pipe valve 10 whenever the pressure in theprimary chamber 139 falls below atmospheric pressure by a predetermined amount in response to a drop in the pressure in the secondary chamber 140 more rapid than can be offset by the induction of air from the atmosphere through the restricted orifice means comprising the compensating vent fitting 90. This means comprises essentially a pilot valve operable in response to such a drop in pressure in thechamber 139 andcavity 197 which, upon such operation, causes opening of a main valve admitting fluid under pressure to the split seat" of the dry-pipe valve 10, i.e., the chamber designated by the reference numeral 53 in Rowley U.S. Pat. No. 2,667,934 previously referred to.

The pilot valve comprises a valve stem 200 slidably mounted in an opening 202 in amember 204 threaded into anopening 206 in one end of themember 132 and sealed thereto by a gasket, as shown; the valve stem 200 being sealed within the opening 202 by an O-ring as shown. At one end of the valve stem 200 is provided with a valve head 200 which, in the closed position of the pilot valve, engages aseat 210 retained within theopening 206 in themember 132. At its opposite end the valve stem 200 is secured to adisk 212 which is adhesively secured to adiaphragm 214 the edge of which is retained betweenmembers 195 and 204 bybolts 216 securing said members together. The opposite side of thediaphragm 214 is engaged bydisk 216 which is urged by aspring 218 compressed between thedisk 216 and a wall ofthemember 195, in a direction to maintain the valve 200 in contact with itsseat 210. Themember 204 defines acavity 220 which is in communication with the atmosphere through anopening 222, so that upon a drop in pressure in theprimary chamber 139 andcavity 197 more rapid than can be offset by the induction of air from the atmosphere through the compensating vent fitting 90, thediaphragm 214 will move downwardly, as shown in FIG. 4, against the force of thespring 218, carrying thedisk 212 adhesively secured thereto with it and removing thevalve head 208 from itsseat 210.

The main valve comprises apiston 224 slidably mounted in avalve chamber 226 in themember 132 and sealed to the walls thereof by an O-ring, as shown.Piston 224 is provided with avalve head 228 normally retained against aseat 230 by aspring 232 .compressed between one end of a recess in thepiston 224 and aplate 234 bolted and gasketed to the outside wall of themember 132; thepiston 224, when so positioned, dividing thevalve chamber 226 into two portions.

Fluid under pressure is constantly supplied to one portion of thecavity 226 from a source of fluid pressure which may be the air under pressure in the network of sprinkler piping of the automatic sprinkler system; the water under pressure in themain supply line 12; or an independent source of fluid pressure, throughpipe 236 and port 238 (see also FIG. in a wall of thecavity 226, also filling the other portion ofcavity 226 by virtue of aconstricted port 240 in thepiston 224. The fluid under pressure also passes from the second portion of thecavity 226 through alarger port 242 in themember 132 to theopening 206 in themember 132 at the inlet side of thepilot valve 208.

Because theport 240 in thepiston 224 is more constricted than theport 242 and the opening disclosed by the opening of thepilot valve 208 to the outlet side of the main valve, the opening of thepilot valve 208 creates a pressure differential across thepiston 224, moving it leftward, as shown in FIG. 4, against the force of thespring 232, and removing themain valve 228 from itsseat 230. This permits fluid under pressure to pass from thecavity 226 into apipe 244 threaded into anopening 246 in themember 132 communicating with the outlet side of themain valve 228 and thence to the split seat" of the dry-pipe valve 10, causing immediate opening thereof.

In the operation of this embodiment of the device of the present invention, slow changes in the air pressure in the sprinkler piping network of the automatic sprinkler system are offset by the induction or expulsion of air from thechamber 139 andcavity 197 through the compensating vent fitting 90 without displacing thepilot valve 208 from itsseat 210. However, in the event of a rapid drop of air pressure in the sprinkler piping network, such as the pressure drop produced by the opening of a thermally responsive valve of a sprinkler head, the pressure in thechamber 139 andcavity 197 drops more rapidly than air can be indicted through the compensating vent fitting 90, thus producing a partial vacuum in thecavity 197 and removing thepilot valve 208 from itsseat 210. The opening of the pilot valve causes, as described above, the opening of themain valve 228, permitting fluid under pressure to pass from thesupply pipe 236 through themain valve 228 and thence through thepipe 244 to thepipe 22. The drain clapper valve 24 closes automatically, as described in the patent of Rowley U.S. Pat. No. 2,667,934, and the fluid pressure thereby created in thepipe 22 enters the split seat chamber designated 53 in said patent, causing immediate opening of the dry-pipe valve 10.

What is claimed is:

l. A quick-opening device for the dry-pipe valve of a drypipe automatic sprinkler system comprising a compartment having piston means therein dividing the same into primary and secondary chambers; said piston means being movable to inversely vary the relative volumes of said chambers, yieldable means for impelling said piston means in a direction to decrease the volume of the secondary chamber, means for connecting the secondary chamber with the piping network of a dry-pipe automatic sprinkler system, whereby air pressure in said system may restrain movement of said piston means by said yieldable means, a restricted orifice connecting said primary chamber with the atmosphere, and control means adapted for connection to control the opening of dry-pipe valve of a dry-pipe automatic sprinkler system and operable in response to a decrease in air pressure in said primary chamber valve, means responsive to opening of said pilot valve for conby a predetermined amount below atmospheric pressure.

2. A quick-opening device for the dry-pipe valve of a drypipe automatic sprinkler system comprising a compartment having piston means therein dividing the same into primary and secondary chambers; said piston means being movable to inversely vary the relative volumes of said chambers, yieldable means for impelling said piston means in a direction to decrease the volume of the secondary chamber, means for connecting the secondary chamber with the piping network of a dry-pipe automatic sprinkler system, whereby air pressure in said system may restrain movement of said piston means by said yieldable means, a restricted orifice connecting said primary chamber with the atmosphere, and control means comprising a vacuum-responsive electrical switch adapted for connection to control the opening of the dry-pipe valve of a drypipe automatic sprinkler system and operable in response to a decrease in air pressure in said primary chamber by a predetermined amount below atmospheric pressure.

3. A quick-opening device for the dry-pipe valve of a drypipe automatic sprinkler system comprising a compartment having piston means therein dividing the same into primary and secondary chambers; said piston means being movable to inversely vary the relative volumes of said chambers, yieldable means for impelling said piston means in a direction to decrease the volume of the secondary chamber, means for connecting the secondary chamber with the piping network of a dry-pipe automatic sprinkler system, whereby air pressure in said system may restrain movement of said piston means by said yieldable means, a restricted orifice connecting said primary chamber with the atmosphere, and control means I adapted for connection to control the opening of the dry-pipe valve of a dry-pipe automatic sprinkler system and operable in response to a decrease in air pressure in said primary chamber by a predetermined amount below atmospheric pressure; said control means comprising a normally closed pilot valve, a normally closed main valve adapted for connection with a source of fluid pressure, means operable in response to a decrease in air pressure in said primary chamber by a predetermined amount below atmospheric pressure for opening said pilot ditioning said main valve for opening by fluid pressure from a i source connected thereto.

4. A quick-opening device for the dry-pipe valve of a drypipe automatic sprinkler system comprising a compartment having piston means therein dividing the same into primary and secondary chambers; said piston means being movable to inversely vary the relative volumes of said chambers, yieldable means for impelling said piston means in a direction to decrease the volume of the secondary chamber, means for connecting the secondary chamber with the piping network of a dry-pipe automatic sprinkler system, whereby air pressure in said system may restrain movement of said piston means by said yieldable means, a restricted orifice connecting said primary chamber with the atmosphere, and control means adapted for connection to control the opening of the dry-pipe valve of a dry-pipe automatic sprinkler system and operable in response to a decrease in air pressure in said primary chamber by a predetermined amount below atmospheric pressure; said control means comprising a normally closed pilot valve, a normally closed main valve comprising a valve chamber having an inlet adapted for connection to a source of fluid pressure and including a valve seat, a valve piston longitudinally slidable in said valve chamber and having an end engageable with said seat; said piston being positioned, when engaged with said seat, to divide said valve chamber into a first portion communicating directly with said inlet and second portion, and a restricted orifice in said piston connecting said first and second portions of said valve chamber; a less restricted passage connecting said second portion of said valve chamber with said pilot valve, means operable in response to a decrease in air pressure in said primary chamber by a predetermined amount below atmospheric pressure for opening said pilot valve, whereby fluid entering said valve chamber inlet may displace said piston from said seat.

Claims (4)

1. A quick-opening device for the dry-pipe valve of a dry-pipe automatic sprinkler system comprising a compartment having piston means therein dividing the same into primary and secondary chambers; said piston means being movable to inversely vary the relative volumes of said chambers, yieldable means for impelling said piston means in a direction to decrease the volume of the secondary chamber, means for connecting the secondary chamber with the piping network of a dry-pipe automatic sprinkler system, whereby air pressure in said system may restrain movement of said piston means by said yieldable means, a restricted orifice connecting said primary chamber with the atmosphere, and control means adapted for connection to control the opening of dry-pipe valve of a dry-pipe automatic sprinkler system and operable in response to a decrease in air pressure in said primary chamber by a predetermined amount below atmospheric pressure.

2. A quick-opening device for the dry-pipe valve of a dry-pipe automatic sprinkler system comprising a compartment having piston means therein dividing the same into primary and secondary chambers; said piston means being movable to inversely vary the relative volumes of said chambers, yieldable means for impelling said piston means in a direction to decrease the volume of the secondary chamber, means for connecting the secondary chamber with the piping network of a dry-pipe automatic sprinkler system, whereby air pressure in said system may restrain movement of said piston means by said yieldable means, a restricted orifice connecting said primary chamber with the atmosphere, and control means comprising a vacuum-responsive electrical switch adapted for connection to control the opening of the dry-pipe valve of a dry-pipe automatic sprinkler system and operable in response to a decrease in air pressure in said primary chamber by a predetermined amount below atmospheric pressure.

3. A quick-opening device for the dry-pipe valve of a dry-pipe automatic sprinkler system comprising a compartment having piston means therein dividing the same into primary and secondary chambers; said piston means being movable to inversely vary the relative volumes of said chambers, yieldable means for impelling said piston means in a direction to decrease the volume of the secondary chamber, means for connecting the secondary chamber with the piping network of a dry-pipe automatic sprinkler system, whereby air pressure in said system may restrain movement of said pisTon means by said yieldable means, a restricted orifice connecting said primary chamber with the atmosphere, and control means adapted for connection to control the opening of the dry-pipe valve of a dry-pipe automatic sprinkler system and operable in response to a decrease in air pressure in said primary chamber by a predetermined amount below atmospheric pressure; said control means comprising a normally closed pilot valve, a normally closed main valve adapted for connection with a source of fluid pressure, means operable in response to a decrease in air pressure in said primary chamber by a predetermined amount below atmospheric pressure for opening said pilot valve, means responsive to opening of said pilot valve for conditioning said main valve for opening by fluid pressure from a source connected thereto.

4. A quick-opening device for the dry-pipe valve of a dry-pipe automatic sprinkler system comprising a compartment having piston means therein dividing the same into primary and secondary chambers; said piston means being movable to inversely vary the relative volumes of said chambers, yieldable means for impelling said piston means in a direction to decrease the volume of the secondary chamber, means for connecting the secondary chamber with the piping network of a dry-pipe automatic sprinkler system, whereby air pressure in said system may restrain movement of said piston means by said yieldable means, a restricted orifice connecting said primary chamber with the atmosphere, and control means adapted for connection to control the opening of the dry-pipe valve of a dry-pipe automatic sprinkler system and operable in response to a decrease in air pressure in said primary chamber by a predetermined amount below atmospheric pressure; said control means comprising a normally closed pilot valve, a normally closed main valve comprising a valve chamber having an inlet adapted for connection to a source of fluid pressure and including a valve seat, a valve piston longitudinally slidable in said valve chamber and having an end engageable with said seat; said piston being positioned, when engaged with said seat, to divide said valve chamber into a first portion communicating directly with said inlet and second portion, and a restricted orifice in said piston connecting said first and second portions of said valve chamber; a less restricted passage connecting said second portion of said valve chamber with said pilot valve, means operable in response to a decrease in air pressure in said primary chamber by a predetermined amount below atmospheric pressure for opening said pilot valve, whereby fluid entering said valve chamber inlet may displace said piston from said seat.

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