WO2001068188A2

WO2001068188A2 - Dry accelerator for sprinkler system

Info

Publication number: WO2001068188A2
Application number: PCT/US2001/008760
Authority: WO
Inventors: Joseph William Reilly
Original assignee: Victaulic Company Of America
Priority date: 2000-03-16
Filing date: 2001-03-16
Publication date: 2001-09-20
Also published as: AU2001245859A1; WO2001068188A3

Abstract

A dry accelerator (1) for use in a dry, pressurized-gas, liquid sprinkler fire control and suppression system, that is response-sensitive to a decay in gas pressure in the system, caused by a system-triggering event, is disclosed. The dry accelerator is actuated to in turn accelerate the actuation of at least one other device in the system that controls the release of a liquid fire-extinguent. The dry accelerator generally includes a housing with two gas chambers (3, 4) therein, separated by a diaphragm. A rapid decline in system gas pressure causes a disequilibrium in pressure between the two chambers causing the device to become actuated. System response time is shorter than if the dry accelerator were not present, because the system pressure does not have to decline to as low a level before a system check valve is triggered to make the liquid extinguent available at the sprinkler heads. The dry accelerator is response-sensitive to a drop in system pressure of less than about 5 psi from the initial system pressure; and it is utilizable in all types of systems, regardless of the initial system operating gas pressure.

Description

DRY ACCELERATOR FOR SPRINKLER SYSTEM

FIELD OF THE INVENTION

The present invention relates to an accelerator for use in a dry, pressurized-gas,

liquid extinguent sprinkler fire control and suppression system. The dry accelerator of

the present invention is applicable for use in a dry type fire control and suppression

sprinkler system, in which the piping between the source of the pressurized liquid

extinguent, typically water, and individual sprinkler heads is normally pressurized with

a gas, typically air, and is void of liquid until the system becomes actuated. The dry

accelerator of the present invention is utilizable for all ,dry type sprinkler systems,

regardless of system operating gas pressure.

BACKGROUND OF THE INVENTION

Fire control and suppression sprinkler systems generally include a plurality of

individual sprinkler heads, which are usually ceiling mounted about the area to be

protected. The sprinkler heads are normally maintained in a closed condition and

include a thermally responsive sensing member to determine when a fire condition has

occurred. Upon actuation of the thermally responsive member, the sprinkler head is

opened, permitting pressurized water at each of the individual sprinkler heads to freely

flow therethrough for extinguishing the fire. The individual sprinkler heads are spaced

apart from each other, by distances determined by the type of protection they are

intended to provide (e.g. light or ordinary hazard conditions) and the ratings of the individual sprinklers, as deteπriined by industry accepted rating agencies such as

Underwriters Laboratories, Inc., Factory Mutual Research Corp. and/or the National

Fire Protection Association. It should be well appreciated that once the sprinkler heads

have been thermally activated there should be minimal delay for the water flow

through the sprinkler head at its maximum intended volume.

In order to minimize the delay between thermal actuation and proper dispensing

of water by the sprinkler head, the piping that connects the sprinkler heads to the water

source is, in many instances at all times filled with water. This is known as a wet

system, with the water being immediately available at the sprinkler head upon its

thermal actuation. However, there are many situations in which the sprinkler system

is installed in an unheated area, such as warehouses. In those situations, if a wet

system is used, and in particular since the water is not flowing within the piping system

over long periods of time, there is a danger of the water within the pipes freezing.

This will not only deleteriously affect the operation of the sprinkler system, should the

sprinkler heads be thermally actuated while there may be ice blockage within the pipes,

but such freezing, if extensive, can result in the bursting of the pipes, thereby

destroying the sprinkler system. Accordingly, in those situations it is the conventional

practice to have the piping devoid of any water during its non-activated condition.

This is known as a dry fire protection system.

While all fire protection sprinkler systems generally include a check valve for

isolating the sprinkler system piping from the pressurized water source during the non-

activated condition, the design of such check valves for a dry type fire control

sprinkler system has presented various problems. The check valve, which is interposed between the system piping and pressurized water source, includes a clapper,

which when it is in its closed operative condition prevents the flow of the pressurized

water into the sprinkler system piping. The sprinkler piping in the dry fire protection

system normally contains air or some other, inert gas (e.g. nitrogen) under pressure.

The pressurized air, which is present within the sprinkler system piping, is also

presented to the check valve. Should one or more of the sprinkler heads be thermally

activated to its open condition, the pressure of the air within the sprinkler system

piping and check valve will then drop. The check valve must be appropriately

responsive to this drop in pressure, normally in opposition to the system water pressure

also present in the check valve, to move the clapper to its open condition. When this

occurs, it is desirable to have a rapid expulsion of the pressurized air within the check

valve and the sprinkler system piping, to permit the rapid flow of the pressurized water

through the open check valve, into the sprinkler system piping, and through the

individual sprinkler heads to rapidly extinguish the fire.

The check valves intended for dry type fire control sprinkler systems have

typically controlled the clapper movement by the water and the air pressure applied to

its opposite sides. Such fire check valves include an air seal which opposes the

pressurized water seal. To appropriately apply the system air pressure over the surface

of the clapper air seal, a priming water level is oftentimes maintained wil n the check

valve. During normal conditions, when no sprinkler heads have been activated, the

two seals will be at an equilibrium, thereby mamtaining the clapper in its closed

condition. In order to increase the speed of check valve operation upon a drop off of the

system air pressure, occasioned by the activation of one or more sprinkler heads, the

system air pressure is normally applied to the clapper air seal over a substantially

greater area than the water pressure is applied to the clapper water seal. This is known

as a high differential type check valve. A problem of such valves is that should there

be a reduction in the system water pressure after the clapper has opened, there is a

tendency for the clapper to re-close, particularly since the pressure against the opposite

(air) side of the clapper has thereby been increased due to the column of water that has

flowed therethrough. Since the pressure applied against the air seal of the clapper will

now be increased by the column of water extending upwards from the re-closed check

valve, a greater water pressure would now be required to move the clapper to its open

condition. Such disadvantageous re-closure is referred to as a water columning effect.

This could result in failure of the check valve to subsequently open should one or more of the sprinkler heads be thermally activated.

In order to avoid the re-closure of the clapper, prior art dry system check

valves have generally been provided with a mechanical latch to maintain the clapper in

its open condition once it has been activated. The inclusion of such a mechanical

latch, while serving to prevent re-closure, however, disadvantageously requires the

entire sprinkler system to be shut down and the interior of the high differential type

actuator accessed to release the latch and re-close the clapper after the fire has been

extinguished. Thus prior dry system check valves have typically required the main

supply of water to be shut off, the water drained from the system, and then the high

differential check valve opened to manually unlatch and reset the clapper. Recognizing the disadvantage of having to manually access the interior of the check valve, a

mechanism is shown in U. S. Patent Nos. 5,295,503 and 5,439,028, which include a

reset linkage mechanism that is attached to the check valve, and is actuated by the

rotation of an externally accessible handle. As can be well appreciated such a

mechanism adds to the size, cost and complexity of the check valve.

Traditionally, dry pipe valves used in sprinkler systems employ pressurized air

in order to keep water from entering the sprinkler system. Although this pressurized

air is given a

mechanical advantage over the water pressure, typically of from about 5 - 8 : 1,

typical air pressures in dry sprinkler systems are from 30 psi to 50 psi. Displacement of this

volume of air from the piping of the sprinkler system will delay the operation of the

sprinkler control valve, as well as slow the rate of water entry into the sprinkler system

once the control valve is actuated.

Traditional accelerators operate by sensing a rapid decay of sprinkler system

air pressure, caused by sprinkler head activation. Upon the detection of the pressure

loss, the accelerator will divert system air pressure into the middle chamber of the dry

valve the accelerator is attached to. As the sprinkler system air enters the dry valve

mid chamber, the pressure differential in the dry valve is removed and the dry valve

will activate allowing water to enter the sprinkler system.

In a less traditional dry valve, the accelerator, sensing a rapid pressure decay in

the sprinkler system, opens a water port. When the water port opens, water is allowed

to flow from the valve piston. This allows the piston to retract from the valve body, which in turn allows the actuated valve clapper to open and water to flow into the

sprinkler system.

SUMMARY OF THE INVENTION

A dry accelerator according to the present invention, for use in a dry,

pressurized-gas, liquid sprinkler fire control and suppression system, is response-

sensitive to a sudden, rapid decay in gas pressure in the system, caused by a system-

triggering event. The dry accelerator functions to accelerate the actuation of at least

one other device in the system that controls the release of a fire-extmguis ing liquid, or

liquid fϊre-extinguent.

Generally, a dry accelerator according to the present invention comprises a

housing with two gas chambers therein, separated by a diaphragm, such that a first one

of the gas chambers has a first operative condition wherein it is closed to an ambient

external pressure, and a second operative condition wherein it is open to an ambient

external pressure. When the first gas chamber is in its first operative condition, there is an equal gas pressure in the first and second gas chambers, and when the first gas

chamber is in the second operative condition, which operative condition is actuated by

a sudden drop in system gas pressure, caused by a system-triggering event, such as the

opening of one of the remote sprinkler heads due to the detection by the head of a

thermally triggering event. A pressure differential is then established between the first

chamber and the second chamber, as the pressure in the first chamber falls to the

rapidly declining system pressure. The system pressure will decline to the ambient

pressure as pressurized gas in the system begins to flow out of the system via the thermally-actuated, opened sprinkler head. The dry accelerator further has a spring

that is biased to exert a force on a piston which maintains a gas-tight seal of the first

chamber when the first and second chambers are in their first operative condition and

the gas pressures therein are equal. The spring force on the piston is sufficient to maintain the diaphragm in a first, sealing position between the first gas chamber and

the second gas chamber, when the first gas chamber is in its first operative condition,

such that the diaphragm acts to maintain equal gas pressure in the first and second gas

chambers. When the first gas chamber is in its second operative condition, there is a greater pressure in the second gas chamber than in the first gas chamber, the pressure

then also being greater than the force exerted by the spring on the piston to maintain

the diaphragm in its first sealing position, such that the diaphragm is moved to a

second, open position in which it exerts a counter-force on the piston sufficient to

cause the first gas chamber to assume its second operative condition, wherein it is open to external ambient pressure. In this condition, any remaining gas in the first and

second chambers is caused to be evacuated, as the system gas pressure continues to

further decline to the ambient, open system pressure. The ambient, open system

pressure is typically the prevailing surrounding atmospheric pressure, typically about

14.7 psi. At this time, another device in the system, typically a check valve, that

directly controls release of a liquid fire-extinguent to a plurality of sprinkler heads of

the system is caused to be actuated to allow the liquid fire extinguent, which is

typically water, and which may further contain one or more fire-retarding chemicals,

to flow to the plurality of sprinkler heads.

The advantage of the presence of the dry accelerator in the system is that the residual gas pressure in the system, remaining after a decline from an initial system gas

pressure that has been caused to suddenly and rapidly decline due to the system

triggering event, at which the check valve is actuated is higher than would be required

to actuate the check valve or other device in the system if the dry accelerator were not

present. Without the presence of the accelerator, the system pressure would have to decline to a lower pressure before the check valve was triggered if there were no dry

accelerator present in the system. The dry accelerator of the present invention is

response-sensitive to a fall in system pressure from an initial system pressure of less

than about 5 psi from the initial system pressure. The dry accelerator of the present

invention, moreover, is utilizable in all types of systems, both those which operate at

higher gas pressure, of the order of from about 30 psi to about 60 psi initial system gas

pressure, and those which operate at low gas pressure, of the order of from about 5 psi

to about 20 psi initial system gas pressure.

The dry accelerator of the present invention, for use in a dry, pressurized-gas,

water sprinkler fire control and suppression system generally includes a housing having

an upper chamber and a lower chamber spaced along a vertical axis, in communication

with one another, with the upper chamber further having an upper gas compartment

for containing a volume of gas and the lower chamber having a lower gas compartment

for containing a volume of gas. The upper gas compartment has a gas orifice therein,

the upper gas compartment being in fluid contact with a valve actuating device and the

sprinkler system. The dry accelerator further has an accelerator shaft, within the upper

gas compartment, with an orifice therein being in communication with the gas orifice;

a diaphragm, positioned at a base of the accelerator shaft, having a diaphragm orifice therein for the passage of gas therethrough, the diaphragm being moveable and flexible

alternatively between a first position wherein the diaphragm forms a fluid-tight seal

between the upper gas compartment and the lower gas compartment, and a second

position wherein the seal between the upper gas compartment and the lower gas

compartment is open; a piston, slideably moveable in the accelerator shaft; a restrictor

for equalizing the pressure in the upper and lower gas compartments; and a spring,

biased to mamtaining the piston in a closed position. When the air pressure in the

lower chamber exceeds the spring force, the piston is urged upward, thereby breaking

the upper seal and causing air to be evacuated from the control valve actuator. The

responsiveness of the accelerator can be adjusted by taming an adjusting nut to vary

the amount of compression of the spring, and thus, the force exerted on the piston

when in a closed position.

The dry accelerator of the present invention, particularly a Series 746 dry

accelerator, works in conjunction with either a Series 753 A dry actuator or a Series

776 Ultimator actuator-accelerator, as are manufactured and sold by Victaulic Fire

Safety Company LLC, Easton, PA, USA. The dry accelerator of the present invention

senses a rapid pressure loss in the sprinkler system. When this rapid pressure loss is

detected, the dry accelerator of the present invention opens an air port to atmosphere.

This allows the air in the upper chambers of the dry accelerator to be rapidly exhausted

to atmosphere. With the loss of air pressure in the dry accelerator, other devices in the

system, particularly the check valve, are actuated and are caused to operate in their

normal manner, thereby opening the water line from the actuated valve piston to atmosphere. The actuated valve is then activated in its intended manner allowing

water to enter the sprinkler system.

It is, therefore, a primary object of the present invention to provide an

improved dry accelerator, having particularly utilization in conjunction with dry fire control and suppression sprinkler systems.

Another object of the present invention is to provide a dry accelerator which

operates in response to a drop in system air pressure, and provides for rapid evacuation

of gas within the dry accelerator to enhance its speed of operation.

Still another object of the present invention is to provide a dry accelerator for

use in dry fire control and suppression sprinkler systems, wherein the time for system

gas pressure to vent and extinguishing liquid to flow to sprinkler heads of the system is

greatly reduced.

A still further object of the present invention is to provide a dry accelerator for

use in dry fire control and suppression sprinkler systems, wherein an actuator is more

rapidly actuated so as to rapidly actuate the check valve in the system.

An additional object of the present invention is to provide a dry accelerator for use in dry fire control and suppression sprinkler systems, wherein the dry accelerator is responsive to a rapid decline in system gas pressure.

Yet another additional object of the present invention is to provide a dry

accelerator for use in dry fire control and suppression systems utilizing a low-

differential check valve.

Yet another additional object of the present invention is to provide a dry accelerator which provides a fast response to the check valve and prevents air and water buildup in

an actuator-accelerator.

These as well as other objects of the present invention will become apparent

upon a consideration of the following detailed description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a cross-sectional view of a dry accelerator for a dry sprinkler system

according to the present invention, shown in the closed position.

Fig. 2 is a cross-sectional view of a dry accelerator for a dry sprinkler system

according to the present invention, shown in the open position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE

INVENTION

Referring now initially to Fig. 1, a particularly preferred embodiment of a dry

accelerator of the present invention for use in a dry sprinkler system, such as is made

and sold by Victaulic Fire Safety Company LLC, Easton, PA, USA, as the Series 746

Dry Accelerator, is installed in a dry fire control and suppression sprinkler system so

as to be in fluid communication with both an actuator or actuator-accelerator (C), such

as a Series 753A or Series 776 actuator-accelerator, as manufactured by Victaulic

Company of America, Easton, PA, USA, and a check valve (B), which provides a fire

extmguishing liquid to the piping and a plurality of individual sprinkler heads (not shown). The system, including the actuator-accelerator B, and the dry accelerator 1 of

the present invention, is first readied for operation by placing the dry accelerator 1 in a

closed, set, ready-for-use condition. The dry accelerator 1 is set by first introducing a

gas, usually air, into the sprinkler system piping, actuator-accelerator C, and the dry

accelerator 1 itself.

The dry accelerator 1 includes a housing 2, which has a vertical axis, and itself

includes two chambers, namely, an upper chamber 3, and a lower chamber 4, which

are spaced along the vertical axis. The housing is constructed of a high strength

metallic material, typically brass. However, it should be understood that other

materials and processes of manufacture can be used. For instance the housing 2 could

be constructed of machined stainless steel or suitably molded plastic or other materials

having the requisite strength.

The upper chamber 3 and the lower chamber 4 are in communication with each

other. The communication between the upper chamber 3 and the lower chamber 4 is

made fluid-tight by extending the diaphragm 10 fully to the ends of the upper and

lower chambers, or, alternatively, by the provision of at least one sealing gasket or

device, such as an O-ring (not shown), at the juncture of respective side ends of the

upper and lower chambers.

The upper chamber 3 has an upper gas compartment 5 therein, for the

accumulation of a volume of gas. The lower chamber 4 has a lower gas compartment 6

therein for the accumulation of a volume of gas. The upper gas compartment 5 and

the lower gas compartment 6 are in fluid communication with each other. The upper

gas compartment 5 is also in fluid communication with a valve actuating device, such as the Series 753 A or Series 776 Victaulic actuators, as well as with the sprinkler

system itself.

Pressurized gas from an external source E enters the system through a sprinkler

control valve trim (not shown) and then into the upper gas compartment 5 of the dry

accelerator 1, through restricted gas orifice 7. The gas then passes through accelerator

shaft orifice 9 in accelerator shaft 8, located in upper gas compartment 5, where the

gas impinges on the diaphragm 10, causing the diaphragm 10 to deflect away from a

bottom of the accelerator shaft 8. The diaphragm 10 has a diaphragm orifice 11

extending through the diaphragm, through which the gas passes on its way to a piston

12, located below the diaphragm 10. The diaphragm 10 is fabricated from a flexible

material, and is preferably formed of rubber. The gas then passes through piston

orifice 13 in the piston 12, and finally into the lower gas compartment 6.

At the time of initialization of the dry accelerator 1, the gas pressure in the

upper gas compartment 5 and the lower gas compartment 6 is the same. In this

condition, the diaphragm 10 is in a flat, un-deflected condition, at the bottom of the

accelerator shaft 8. In this condition, a reverse flow of gas from the lower gas

compartment 6 through accelerator shaft orifice 9 to upper gas compartment 5 is

prevented.

Coiled mechanical spring 17, which surrounds the piston 14, is in a relaxed

state during this initialized condition of the dry accelerator, and it provides a closing force on the piston 12 to close off the accelerator shaft 8, by urging the upper seal 18

into a closed position abutting against adjusting nut 19. The pressure in the lower gas

compartment 6 can only be relieved through the restrictor 14, which has a first opening 15 on the upper gas chamber side, and a second opening 16 on the lower gas chamber

side. Restrictor 14 allows the pressure in the lower gas compartment 6 to remain equal

to the pressure in the upper gas compartment 5, during relatively minor sprinkler gas

pressure perturbations. This same gas pressure also acts on the valve actuating device.

Referring now to Fig. 2, which shows the dry accelerator of the present

invention in an actuated, open condition, when there is a sudden decay of the sprinkler

system air pressure, such as is caused by actuation of one of the sprinkler heads, the

gas pressure in the upper gas compartment 5 of the dry accelerator 1 simultaneously

falls as gas flows from the upper gas compartment 5 back through the gas orifice 7. As

the gas pressure in the upper gas compartment 5 falls, the diaphragm 10 seals against

the base of accelerator shaft 8. Gas pressure in the lower gas compartment 6 is

prevented from falling by the restrictor 14, which is in fluid communication between

the lower gas compartment 6 and the upper gas compartment 5. Gas flows from the

lower gas compartment 6 through restrictor 14 at a slower rate than from the upper gas

compartment 5. Before the gas pressure in the upper gas compartment 5 decays by

approximately 5 psi, the gas pressure in the lower gas compartment 6 creates a

differential force acting on the piston 12 in the accelerator shaft 8, sufficient to

overcome a closing force caused by spring 17, that urges the upper seal 18 to move

away from the adjusting nut 19, thereby exhausting the upper gas compartment 5 to

atmosphere. Gas exiting from the upper gas compartment 5 to atmosphere

simultaneously causes gas to exhaust from the sprinkler control valve actuator C,

causing the actuator C to operate in its intended manner to open an extinguishing liquid

line A, ranning from the sprinkler control valve piston B, thereby causing the sprinkler control valve to actuate and allow extmguishing liquid to enter the sprinkler system and

flow to the individual sprinkler heads (not shown).

While the present invention has been disclosed with reference to specific

embodiments and particulars thereof, many variations thereof will be apparent to those

skilled in the art. Accordingly, it is intended that the scope of the invention be

determined by the following claims.

Claims

CLAIMS What is claimed is:

1. A dry accelerator for use in a dry, pressurized-gas, liquid sprinkler fire control and

suppression system, the dry accelerator being response-sensitive to a sudden, rapid decay

in gas pressure in the system, caused by a system-triggering event, for accelerating the

actuation of at least one other device in the system that controls the release of a liquid fire-

extinguent.

2. The dry accelerator according to claim 1, which operates on the basis of gas pressure and

has no liquid flow therethrough.

3. The dry accelerator according to claim 2, which operates such that an equilibrium gas

pressure is maintained between two chambers of the dry accelerator when the dry

accelerator is in a first, ready operative condition, and there is a gas pressure differential

between the two chambers of the dry accelerator when the dry accelerator is in a second,

actuated operative condition.

4. The dry accelerator according to claim 1, wherein the system is a high gas pressure

system, wherein the initial system gas pressure is from about 30 psi to about 60 psi, and

the at least one other device being actuated is selected from the group consisting of an

actuator and a check valve.

5. The dry accelerator according to claim 1, wherein the system is a low gas

pressure system, wherein the initial system gas pressure is from about 5 psi to

about 30 psi, and the at least one other device being actuated is selected from

the group consisting of an actuator and a check valve.

6. The dry accelerator according to claim 3, wherein the gas pressure differential

between the two chambers required to actuate the dry accelerator is caused by a decline in system pressure of not more than about 5 psi from an initial system

pressure.

7. The dry accelerator according to claim 2, wherein the gas is air.

8. A dry accelerator for use in a dry, pressurized-gas, liquid sprinkler fire control

and suppression system, the dry accelerator being response-sensitive to a

sudden, rapid decay in gas pressure in the system, caused by a system-

triggering event, for accelerating the actuation of at least one other device in

the system that controls the release of a liquid fire-extinguent, the dry

accelerator comprising a housing with two gas chambers therein, separated by

a diaphragm, such that a first one of the gas chambers has a first operative

condition wherein it is closed to an ambient external pressure, and a second

operative condition wherein it is open to an ambient external pressure, such

that when the first gas chamber is in its first operative condition, there is an

equal gas pressure in the first and second gas chambers, and when the first gas chamber is in the second operative condition, which operative condition is

actuated by a sudden drop in system gas pressure, caused by a system-

triggering event, a pressure differential is established between the first chamber

and the second chamber, the dry accelerator further having a spring that is

biased to exert a force on a piston which maintains a gas-tight seal of the first

chamber when the first and second chambers are in their first operative

condition and the gas pressures therein are equal, the spring force on the piston

being sufficient to maintain the diaphragm in a first, sealing position between

the first gas chamber and the second gas chamber, when the first gas chamber

is in its first operative condition, such that the diaphragm acts to maintain equal

gas pressure in the first and second gas chambers, and wherein when the first

gas chamber is in its second operative condition, there is a greater pressure in

the second gas chamber than in the first gas chamber, the pressure then also

being greater than the force exerted by the spring on the piston to maintain the

diaphragm in its first sealing position, such that the diaphragm is moved to a

second, open position in which it exerts a counter-force on the piston sufficient

to cause the first gas chamber to assume its second operative condition,

wherein it is open to external ambient pressure, and in which condition, any

remaining gas in the first and second chambers is caused to be evacuated,

whereupon another device in the system that directly controls release of a liquid

fire-extinguent to a plurality of sprinkler heads of the system is caused to be

actuated while a residual gas pressure in the system, remaining after a decline

from an initial system gas pressure that has bee caused to suddenly and rapidly decline due to a system triggering event, is higher than would be required to

actuate the other device in the system that controls release of the liquid fire

extinguent to the plurality of sprinkler heads if the dry accelerator were not

present in the system.

9. The dry accelerator according to claim 8, wherein the system is a high gas

pressure system, wherein the initial system gas pressure is from about 30 psi to

about 60 psi, and the at least one other device being actuated is selected from

the group consisting of an actuator and a check valve.

10. The dry accelerator according to claim 8, wherein the system is a low gas

pressure system, wherein the initial system gas pressure is from about 5 psi to

about 30 psi, and the at least one other device being actuated is selected from

the group consisting of an actuator and a check valve.

11. The dry accelerator according to claim 8, wherein the first chamber is caused

to enter into its second operative condition when the gas pressure differential

between the gas pressure in the first chamber when in its first operative

condition and the system gas pressure after a sudden rapid decline therein from

an initial system gas pressure, due to a system-triggering event, is not greater

than about 5 psi.

12. The dry accelerator according to claim 8, wherein the gas is air.

3. A dry accelerator (1) for use in a dry, pressurized-gas, liquid sprinkler fire

control and suppression system, the dry accelerator comprising:

a.) a housing (2), having a vertical axis, and including an upper chamber

(3) and a lower chamber (4), with the upper and lower chambers (3,4)

being spaced along the vertical axis, such that the upper chamber (3)

and the lower gas (4) are in communication with one another;

b.) the upper chamber (3) further having an upper gas compartment (5)

therein, with orifice (7) in fluid communication therewith, and in fluid

communication with a pressurized gas source, with the upper gas

compartment (5) being in fluid contact with a valve actuating device and

the sprinkler system;

c.) an accelerator shaft (8), within the upper gas compartment (5), having

an accelerator shaft orifice (9) therein, the accelerator shaft orifice (9)

being in communication with the gas orifice (7);

d.) a diaphragm (10), positioned at a base of the accelerator shaft (8),

having a diaphragm orifice (11) therein, for the passage of gas

therethrough, the diaphragm (10) being moveable and flexible

alternatively between a first position wherein the diaphragm (10) forms

a fluid-tight seal between the upper gas compartment (5) and the lower

gas compartment (6), and a second position wherein the seal between

the upper gas compartment (5) and the lower gas compartment (6) is

open; e.) a piston (12), slideably moveable in the accelerator shaft (8), having a

piston orifice

(13) therein for the passage of gas therethrough;

f.) the lower gas compartment (6), situated below the piston (12) and in

fluid communication therewith, for the accumulation of a volume of

gas;

g.) a restrictor (14), disposed between the upper gas compartment (5) and

the lower gas compartment (6), with a first opening (15) on the upper

gas compartment side, and a second opening (16), on the lower gas

compartment side, for equalizing the pressure between the upper gas

compartment (5) and the lower gas compartment (6); and

g.) a spring (17), for alternatively causing movement of the piston (14), the

spring being biased to maintain the piston in a position wherein an open

passage is maintained between the accelerator shaft and the upper gas

compartment (5) by relaxing a fluid-tight seal between an upper seal

(18) and an adjusting nut (19), when the dry accelerator is in an

actuated condition and there is a rapid reduction in system gas pressure,

which otherwise opposes a compressive force of the spring (17), when

the dry accelerator is in a ready condition.

14. The dry accelerator according to claim 13, wherein the system is a high gas

about 60 psi, and the at least one other device being actuated is selected from

the group consisting of an actuator and a check valve.

15. The dry accelerator according to claim 13, wherein the system is a low gas

pressure system, wherein the initial system gas pressure is from about 5 psi to

about 30 psi, and the at least one other device being actuated is selected from

the group consisting of an actuator and a check valve.

16. The dry accelerator according to claim 13, wherein the gas is air.

17. A dry fire control and suppression sprinkler system comprising:

a.) a dry accelerator according to claim 1, for accelerating actuation of an

actuator;

b.) an actuator, connected to the accelerator, for actuating a check valve; c.) a check valve, connected to a plurality of sprinkler heads, for

distributing an extinguishing liquid to the plurality of sprinkler heads;

d.) a plurality of sprinkler heads, for delivering an extmguishing liquid to a

fire;

e.) piping for interconnecting the plurality of sprinkler heads and the dry accelerator, the actuator, and the check valve;

f.) a pressurized gas supply source, for supplying a pressurized gas, for

circulation in the piping of the system when the system is in a non-

activated condition, and to pressurize the accelerator, the actuator, and

the check valve; and g.) a pressurized liquid supply source, for supplying a pressurized liquid,

used to extinguish a fire, to the system when the system is in an

activated condition, and for pressurizing the actuator and the check

valve, when in a ready condition.

18. The dry fire control and suppression sprinkler system according to claim 17,

wherein the pressurized gas is air.

19. The dry fire control and suppression sprinkler system according to claim 17,

wherein the gas pressure is not more than about 60 psi.

20. The dry fire control and suppression sprinkler system according to claim 17,

wherein the pressurized liquid is water.

21. The dry fire control and suppression sprinkler system according to claim 19,

wherein the water further contains a fire-retarding chemical.

22. A dry fire control and suppression sprinkler system comprising:

a.) a dry accelerator according to claim 8, for accelerating actuation of an

actuator;

b.) an actuator, connected to the accelerator, for actuating a check valve;

c.) a check valve, connected to a plurality of sprinkler heads, for

distributing an extinguishing liquid to the plurality of sprinkler heads; d.) a plurality of sprinkler heads, for delivering an extmguishing liquid to a

fire;

e.) piping for interconnecting the plurality of sprinkler heads and the dry

accelerator, the actuator, and the check valve;

f.) a pressurized gas supply source, for supplying a pressurized gas, for

circulation in the piping of the system when the system is in a non-

activated condition, and to pressurize the accelerator, the actuator, and

the check valve; and

g.) a pressurized liquid supply source, for supplying a pressurized liquid,

used to extinguish a fire, to the system when the system is in an

activated condition, and for pressurizing the actuator and the check

valve, when in a ready condition.

23. The dry fire control and suppression sprinkler system according to claim 22,

wherein the pressurized gas is air.

24. The dry fire control and suppression sprinkler system according to claim 22,

wherein the gas pressure is not more than about 60 psi.

25. The dry fire control and suppression sprinkler system according to claim 22,

wherein the pressurized liquid is water.

26. The dry fire control and suppression sprinkler system according to claim 25,

wherein the water further contains a fire-retarding chemical.

27. A dry fire control and suppression sprinkler system comprising:

a.) a dry accelerator according to claim 13, for accelerating actuation of an

actuator;

b.) an actuator, connected to the accelerator, for actuating a check valve;

c.) a check valve, connected to a plurality of sprinkler heads, for

distributing an extmguishing liquid to the plurality of sprinkler heads;

d.) a plurality of sprinkler heads, for delivering an extinguishing liquid to a

fire;

e.) piping for interconnecting the plurality of sprinkler heads and the dry

accelerator, the actuator, and the check valve;

f.) a pressurized gas supply source, for supplying a pressurized gas, for

circulation in the piping of the system when the system is in a non-

activated condition, and to pressurize the accelerator, the actuator, and

the check valve; and

g.) a pressurized liquid supply source, for supplying a pressurized liquid,

used to extinguish a fire, to the system when the system is in an

activated condition, and for pressurizing the actuator and the check

valve, when in a ready condition.

28. The dry fire control and suppression sprinkler system according to claim 27,

wherein the pressurized gas is air.

29. The dry fire control and suppression sprinkler system according to claim 27,

wherein the gas pressure is not more than about 60 psi.

30. The dry fire control and suppression sprinkler system according to claim 27,

wherein the pressurized liquid is water.

31. The dry fire control and suppression sprinkler system according to claim 30,

wherein the water further contains a fire-retarding chemical.