US1942822A

US1942822A - Automatic fire-extinguishing system

Info

Publication number: US1942822A
Application number: US163629A
Authority: US
Inventors: Ernest A Lowe; John R Hamilton
Original assignee: Automatic Sprinkler Corp
Current assignee: Automatic Sprinkler Corp
Priority date: 1927-01-26
Filing date: 1927-01-26
Publication date: 1934-01-09
Anticipated expiration: 1951-01-09

Description

1934- E. A. LOWE ET AL AUTOMATIC FIRE EXTINGUISHING SYSTEM 9 Lu 2 0 Z 6 7 3 3 2 3 3 O 4 7 3 5 6 53 5. o U 0 3 3 6 4/ m O I 0 7 Z A 0 I Q INVENTORS Ernesz 14. Lowe Jo/m R. //a Won 5% ffi WMM ATTORNEYS Patented Jan. 9, 1934 UNITED. STATES J'P'ATENT OFFICE AUTOMATIC. FIRE-EXTINGUISHING SYSTEM ration of Delaware Application January'26,

26 Claims.

The present invention relates to fire extin-. guishing systems and more particularly to that form of. the-same wherein the supply of the fire extinguishing fluid to the system iscontrolled by means responsive to a decrease of the normal pressure in the system consequent upon the opening of a sprinkler head or other outlet thermostatically controlled.

In the preferred system embodying our present invention the pressure acting upon the means supplying the extinguishing fluid or medium is air and acts upon a main valve in away topress the same to its seat, the opening of saidvalve in response to the decrease of air pressure being effective to cause water or similar medium to pass into the distributing piping, for emission through the head or outlet in the fire Zone to control or extinguish the. fire.

The invention will accordingly be described as carried out in connection with such. a preferred system. and also for purposes of illustration the opening. of the outlet will be described as automatically produced by the action of a fuse or fusible. device which releases the: normally closed outlet. valve upon the attainment of a fixed or determinate. temperature sufiicient to melt or soften the fuse. so that it shall not be longer efiective to keep the outlet in closed position.

The principal object of our. invention is, gener-- ally speaking, to. expedite the arrival of the fire extinguishing medium at the outlet or sprinkler head. upon the occurrence of fire or other abnormal thermic condition and to this end the invention consists essentially in the provision of means in connection withthe control, valve or means for supplying fluid extinguishing medium to the pipes upon a drop in pressure in the pip.- ing, of supplemental means forcausing said valve to open or function by operation of thermally responsive means more quickly responsive to heat in the fire zone of the outlet than said fixed or determinate temperature device, said quickly responsive device. embodying by preference a pressure responsive device operative by increase of air pressure generated at a greater thana predetermined or adjusted rate by the heating of air in the fire zone of the outlet,

More specifically stated, the object of our invention in its preferred form is to permit the main control valve to function in the usual way upon a sudden drop in pressure in the dry pipe system due, for instance, to the operation of a sprinkler head and also to cause the. said control valve or other valve controlling the. supply of fire extinguishing medium to the systemto 1927. SerialNo. 163,629 ((21. 169-1 1),

function throughanincrease in air pressure consequent upon the heating effect of fire on said piping. in, the area to be: protected, thereby causing the fire extinguishing medium to be supplied to. the system. before it could be otherwise supplied as the consequence of the opening of the automatic sprinkler head or other thermostatically controlled outlet which cannot act until the'sol'der link or other thermostatic means controlling the sprinkler or other outlet has absorbed suificient heat to cause it to function in the usual way.

Oneof the usual objections to the dry pipe system is. that time is. required for passage of the fire extinguishing medium through the system. to the outlet, a disadvantage which can be overcome by the adoption of the system known as thefwet. pipe system in which water is always present in the piping ready to issue immediately on the fusing of a head or functioning or other thermostatically controlled outlet; but in such system. the. objection ispresent that the water is liable to. freeze. in the piping while, on the contrary, no such difficulty is present. in the case of. the dry pipe system wherein the fire extinguishing medium is excluded. from the piping until the occurrence. of fire.

By our present invention the advantages of the dry pipe. system as respects non-freezing can. be. attained while at the same time, owing to thefunctioning of. the control valve before the thermostatically controlled sprinkler head or other outlet would otherwise cause it to function, the practical advantage of the wet pipe system in respect to prompt discharge of the fire extinguishing medium on the occurrence of fire can be retained.

Further our-invention consists in the combination of distributing pipes for the fireextinguishing. medium, a thermostatically controlled sprinkler head v connected therewith, a valve normally held closed by pressure of air in the piping andcontrolling the supply of fire extinguishing medium thereto, said valve acting on relief of the pressure due to the opening of said sprinkler head, supplemental means responsive to thermostatic action and operating thermostatically more promptly than the thermostatic control for the sprinkler head and means. controlled thereby for causing the dry-pipe valve to function before the sprinkler head opens or functions under its own thermostatic control to open said valve.

Our invention. consists further in the combination in a dry pipe system of means responsive to a drop in the air pressure therein for causing the The invention also consists specifically in the combination with the same valve which controls the supply to the distributing system and that ordinarily functions by decrease of air pressure therein, of means responsive to anincrease of the air pressure in the system due to heat in the fire area for also causing-said valve to open.

Our invention also consists broadly in the combination with normally inactive supply means for supplying a fire extinguishing medium to the piping and normally subject to pressure of fluid in said piping and held inactive by said pressure but adapted to come into action on the relief of said pressure, of an outlet in the fire zone normally closed but adapted to open and relieve said pressure and cause the supply means to act and means for causing said supply means to function subject to the control of a pressure-responsive device responsive to increase of air pressure increasing at a greater than a predetermined or adjusted rate and produced by heating of the air in the fire zone.

In carrying out our invention we prefer to employ a pressure modifying or equalizing vent adapted to neutralize changes of pressure of air incident to normal or regular changes of temperature in the particular situation'in which the device is used. Saidequalizing vent is sorestricted or adjusted however that the heat due'to a fire will result in expanding the air sufficiently to produce the desired operating or controlling pressure or force.

The invention also consists in the specific combinations of devices and apparatus more particularly described in connection with the accompanying drawing for effecting the general purposes of our invention and in other details of construction and combinations of parts employed for replenishing or maintaining the normal air pressure in the dry piping.

The accompanying drawing shows in partial vertical section and side elevation an apparatus embodying our invention in one of the forms it may take in practice.

Assuming that the invention is carried out in connection with water as fire extinguishing medium, the main water supply pipe thereof is indicated at 1 while 2 indicates a suitable manually controlled gate valve for shutting off the supply of water to the apparatus at will. At 3 is indicated a valve chamber of an automatic,

differential, main valve adapted to function on relief of the ordinarily maintained pressure in the main distributing pipe '7 and its branches. Said valve is here shown as of the ordinary differential type and as having a clapper or valve 4 held to its seat against any pressure of water in the main 1 by means of a disk, clapper -or valve 5 hinged at 6 and suitably connected-to the valve 4 so that the superior pressure of the fluid in the chamber 3 will normally keep the water valve 4 on its seat. As shown, the valve 5 has, as ordinarily, a larger surface area exposed to pressure of the air than the pressure area of 4 exposed to water, thus insuring the retention of valve 4 on its seat under the normal conditions of pressures in the device 1 and 7.

zone of the sprinkler.

The main pipe 7 of the piping system is connected to the usual pipes having outlets thermostatically controlled, one of such outlets being indicated at 8 as a usual sprinkler head thermostatically controlled and of typical form wherein an outlet valve is normally held closed but is adapted to open when released through the melting of a fuse and thereupon opens. As these devices and the arrangement of the system are of conventional form and well understood, they need not be further described.

The functioning of the valve 4 in the usual way of the dry pipe system occurs when an outlet of the system is opened by the action of the thermostat thus relieving the air pressure on valve disk or clapper 5 and permitting any superior pressure then existing on valve or clapper 4 to open the same and throw back the valve 5 so that the fire extinguishing medium may pass freely from 1 to '7. V

' According to the preferred manner of carrying out our present invention the admission of the fire extinguishing medium to the piping 7 through the action of the valve 4 or any other controlling valve may be also brought about through the force of expansion of a heated'confined body of air exposed to heating in the fire 7 As an example of our invention we show how we may employ the body of air in the main tubing 7 for this purpose, said body of air being however normally under positive pressure for the special purposes herein described. The heating of said air acts to expand thesame and increased force of expansion or of pressure then serves as the controlling force for the supplemental valve controlling means.

One of the ways in which the force of expansion of the heated air may be utilized for causing the main valve to open is by the admission of fluid pressure into the space 3 beneath the element 5 of the differential valve so as to destroy the differential condition by force assisting the tendency ofthe valve 4 to open under the pressure normally applied to it. The increase of pressure in the chamber 3' consequent upon the increase of pressure in the pipe 7 of the system due to heating of the air in said pipe or its connections may be brought about by devices constructed and functioning as follows: I

At 10 is shown a chamber or enclosure connected by pipe 9 with the piping 7 and containing a diaphragm 13 exposed to the air pressure within said chamber. Said diaphragm when moved under the effect of an abnormal pressure,

serves to'open a valve 19 and thereby open communication between the chamber 3 and a suitable source of air pressure through a pipe 20. Conveniently the pressure of air for acting on the valve disk 5 may be derived from the air in "the chamber 10' and the piping and valve are shown arranged for that purpose. The diaphragm 13 is flexibly supported in the position shown which is its normal one, by suitable spring support '14 or by other means, and may have a flange on the chamber 10 and an upper section 11 thereof as indicated. In order that the pressure responsive diaphragm 13 may be caused to act only when pressure of air heated and expanded in the fire zone occurs at a'greater than a predetermined or adjusted rate we provide a compensation consisting'of an outlet passageway of restricted size operating as a compensating vent or escape for any pressure accumulating against the diaphragm to operate the same its edges secured in position or clamped between and acting to render the diaphragm inoperative under pressure upon the control mechanism for the valve or other supply means unless the pressure accumulates or rises at a greater than a predetermined or adjusted rate under the effects of expanding air heated and expanded in the fire zone and in communication with the space beneath the diaphragm. At 12 is indicated the pressure modifying or compensating vent or passageway hereinbefore referred to. Said passage is connected with the chamber 10, as shown and permits air under pressure to pass from 10 into an expanding chamber 11 and thus relieve to a predetermined extent the force of expansion exerted upon diaphragm in chamber 10. When the air pressure becomes sufficient said diaphragm acts upon the controlling devices as will be presently described. As will be seen the use of the closed expansion chamber prevents waste of pressure of air in the system through the vent 12. By using expansion chamber 11 above the diaphragm air pressure in the section 11 will act upon the diaphragm in opposition to the pressure within the body or section 10 but said pressures are normally balanced owing to the fact that there is communication from chamber 10 to chamber 11 through the pipe in which the compensating device is located so that, after establishment of the air pressure in the chamber 10 from the normal pressure delivered thereto through connection 9 with the system 7, the same pressure will exist above the diaphragm, being established therein through the bypass 12. Normal air pressure being thus existent both above and below the diaphragm, said diaphragm maintains its position so long as the normal pressure is maintained in the piping 7 and its connections; but upon an increase of said normal pressure at some rate which cannot be compensated for by the restricted bypass opening or compensating vent 12, the pressure below will become superior to that above and the diaphragm will be lifted. The lifting of the diaphragm thus produced results in the opening of the valve 19 and this action may be effected by the devices to be now described. These devices are also so constructed that a decrease of pressure in the system which frees the control valve by diminishing the pressure on the disk or clapper 5 will be supplemented in its action by an increase in pressure in the chamber 3'.

Referring now to the devices whereby the valve 19 may be opened by the increase of pressure in 7 and preferably also by the decrease of pressure therein: 16 indicates a rocker arm or lever suitably pivoted within the chamber on a pivot at 17 and deriving motion from the diaphragm 13 by a flexible member 15 connected at one end to a frame or member carried by the diaphragm, and to be presently described more in detail, and connected at its other end to the rocker arm or lever 16 so that motion of the diaphragm away from normal position either up or down'will rock or turn the lever 16 in one direction or the other and cause one or the other of two arms or forks projecting therefrom to either side of its pivotal point 17' to engage the weighted lever 17 and in either case to force the same to the left past the vertical line through its center of support, thus causing it to drop over to the position indicated in dotted lines and to thereby open the valve 19. Upon motion of the diaphragm upwardly, the upper arm or fork 40 will engage and force the weighted lever 17 t0 the left. Upon movement or motion of the diaphragm downwardly the armor fork 41 provided will engage the. weighted lever and. turn it in the required direction for operation of the valve. The action of the lever 16 upon-the valve .19 may be effected inv obvious fashion by an arm projecting from the weighted lever like the arm of a. bell crank and positioned underneath the projection. extending laterally from the pivoted, weighted member carrying the valve 19.

other means and the actuating arm occupies a position. normallybeneath the projection from the valve carrying arm as shown, there being preferably some. play allowed at this point. so that the momentum required by the weighted lever 17in. falling after it passes the center may serve to insure action of the valve.

Under normal conditions and with normal air pressure in the pipe 7 and its connections the parts so far described will be in the position shown and the main valve will be subjected to the pressure of the fluid in the distributing pipe '7. Should a sprinkler or other outlet of the piping system for thefire extinguishing fluid open, the pressure in'l, 9 and 10 would more or less quickly fall and thediminution of pressure below the diaphragm not being equalized by the pressure above, owing to the time required for a corresponding diminution of pressure through the bypass or equalizing vent, the air pressure above the diaphragm will be superior and will move the diaphragm 13 downward. This motion will be transmitted through the flexible member 15 causing the rocker or lever 16 to rotate and force the. weight 17 and lever carried thereby to the. left by the engagement of the lower member of the fork carried by 16 with said weight until the lever passes the center. The weight then falls and the lever engages and lifts the air valve 19. Fluid such as air'under pressure from chamber 10 or other source thereupon enters pipe 20 and, reaching chamber 3", exerts pressure beneath the valve member 5' which conspires with the pressure. under member 4 to lift or open the valve. This action is assisted by the simultaneous diminution of the normal pressure on the upper face of the disk or clapper 5 consequent upon the diminution of the air pressure in the distributing system. As a result thereof the automatic action of the main dry pipe valve in the normal. manner of this type of valve and consequent upon diminution of pressure in the system is supplemented and assisted by the action of a supplemental pressure admitted through pipe 20 to the chamber 3, and the main valve 4 is thereby quickly and. positively opened.

It should be understood that the chamber 3' is, in this particular embodiment of our invention, the one ordinarily employed with automatic dry pipe valves and known as the intermediate or atmospheric chamber. The normal purpose of this supplemental chamber is to allow any'leakage that might occur from above the member or clapper 5 or from below the clapper or member Therefore said Said valve.19*is'normally seated by its own weight or r ball 21' which normally lies at the bottom of the elbow or trap of the ball drip as shown and inposition to allow slight flow of water or air to pass over the top of the ball and out of the dripthrough the raised nozzle or spout thereof.

In the event of fire or the existence of conditions requiring the operation of the main control valve to permit the passage of fluid from 1 to 7, the sudden rush of either water or air will cause the ball to roll upward to the constricted section of the spout-shaped body or outlet of the ball drip and close the outlet. When the air is admitted to the pipe 20 the sudden rush thereof will first move the ball 21' and close the outlet and then will fill the section or chamber 3 with air under pressure which will assist the liquid pressure tending to open the valve 4, the tendency to such opening being at such time opposed -to a less extent by the clapper or member 5 owing to the simultaneous diminution of pressure above the same consequent upon the opening of an outlet in the dry pipe system. The con- .joint effect of these actions is to establish the .want of balance between the forces tending to close and to open the main valve and the latter thereupon opens to permit passage of the fluid in the usual way.

, We will now describe the action of the apparatus having reference to the operation referred to at the beginning of the specification in expediting the opening of the main valve by an increase of pressure of air exposed to the influence of the fire or other thermic condition requiring the application of a fire extinguishing medium at the danger point. When the air in the dry pipe system is'heated at the danger zone it immediately expands and the pressure is quickly communicated through pipe 7 to thechamber 10 and diaphragm 13 or other means responsive to changes of fluid pressure. Inasmuch as an equalization of the pressure above and below the diaphragm through the bypass or compensating vent cannot quickly take place and inasmuch as the dry pipe itself and the attachments, such as chamber 10 and its devices, are preferably housed to prevent the parts from freezing or being lowered abnormally in temperature, the air pressure thus caused to increase under diaphragm 13 will lift the same. This motion is transmitted through flexible member 15 thus lifting the arm of the lever 16 to which it is attached instead of depressing the same. The upper arm or fork of such lever now engages the weight 17 and its lever moving the same to the left in the same way that it was. previously moved by the action of the lower arm in the case of the diminution of pressure. This motion effectuates the opening of the valve 19 as before-with the result that an increased pressure results in chamber 3' and the balance of pressures which holds the main valve closed is in effect disturbed so that the valve will open under the effect of the pressure of the fluid in pipe 1.

At this time and under this condition it is quite obvious that when the air pressure from pipe 7 is taken around to the under side of the valve clapper 5 there results a practical balance of pressure on the two sides thereof leaving the per side of the valve disk 5, holds the fluid valve 4 normally closed. As will be obvious, by this operationthe main valve by which the extinguishing fluid is admitted to the piping can be brought into action and the flow established or begun before the outlet, thermostatically controlled, will have opened. This results in expediting the arrival of the fluid at the fire extinguishing outlet, which is, one of the main purposes of our invention.

From the foregoing it will be seen that the normally closed outlet retained closed by the fuse will prevent the escape of the fire extinguishing medium accidentally or abnormally supplied to the piping and whereby damage to property in the absence of fire will be prevented and that in case the fuse or fixed temperature device should fail to operate promptly the supplemental control devices for the supply means such as the main valve will be brought into action by the operation of the pressure responsive means acting through the influence of the confined body of air subject to heating in the fire zone. Furthermore if in the particular system described as embodying our invention impairment of the normal air pressure in the piping should ensue from failure of the supply of air pressure to keep the air pressure in said piping at the desired degree and if as the result thereof the main valve should open the only result would be that the fire extinguishing medium would fill the distributing piping ready for ejection at the outlet ble thisto be done without causing either of the 1 .apparatus actions above described, we may employ the following means:

At 22 is indicateden air pump which can be 'manually or power. driven and automatically controlled in any of the ways known in the art,

said pump being adapted to force air through check valve 23 and control or gate valve 24, through pipe 25, into a chamber 26 the rigid wall of which may be a part of the casting or body for chamber 10 as indicated. In a wall of said 25 tends to force the diaphragm to the left as shown in the dotted lines. A rod or stem connected to the diaphragm, as shown, and suitably guided at its rear end in the wall of the chamber 25 carries at its forward end, or suitably connected or mounted on said end, a notch or fork f member 33 between the arms of which a rear extension of the rocker arm or lever 16 is received when the stem moves toward the rocker or lever 16 under the effect of the pressure on the diaphragm 27. This notch or fork operates as a lock toprevent action of the lever 16 and connected parts during the process of replenishing the air.

Also mounted on the stem and movable therefore with the diaphragm under the pressure in chamber 26 is a collar 29 acting in the fork end of a bell crank lever 30, such bell crank lever having an arm carrying a valve 31 which controls an outlet from chamber 26 into the chamber 10 in obvious fashion. When the valve 31 is lifted by the pressure on diaphragm 2'7 air supplied from the pump isallowed to enter the dry pipe system. By the interlocking of the notched or forked end on the stem 28 the excess pressure established by the pump is prevented from lifting the diaphragm-and causing an operation of the device I its controlled or actuated thereby in a manner already described. The diaphragm and attached rocker arm or lever 16 are thus locked. until sufficient air pressure has been established, after which the pump may be stopped and the control valve 24 is then closed.

At the end of this operation an excessof pressure on the under side of the diaphragm might exist from failure of the bypass to equalize the pressure quickly enough on the two sides of said diaphragm so that if the stem 28 should be .per-

mitted to recede on falling of pressure in the.

chamber 26, the device would be placed in condition to permit the rocker arm 16 to beactuated and thereby bring about a premature action of the main control valve.

To prevent such abnormal elTect we provide means connected with the diaphragm l3-for holding the stem 28 against receding sufiiciently to unlock the lever 16 when the diaphragm 13 is in lifted position due to such unequalized pressures. Such means comprise interlocking members carried respectively by the diaphragm and by. the stem andcomprising in one form of our inventiona depending member 34 attached to the diaphragm and provided with a lug 36 which engages a projection 37 on the stem 28 when the diaphragm is in lifted position, thereby holding the stem forward in such position that it will prevent rotation of the rocker arm 16 until the diaphragm 13 has assumed its normal position through equalization of pressure in chambers .10 and 11. When this occurs the projection 37 will be freed from engagement with the lug '36 and the diaphragm 27 may then recede under its own spring action and go to normal position, thus freeing the rocker arm 16 so that it may perform the valve releasing actions previously described. After the air supply to the pipe 25 is cut ofi by -valve 24 leakage from the chamber 10 through valve 31 is prevented owing to the fact that, as the pressure diminishes, the stem 28 and diaphragm 27 in receding will close said valve 31. A guide 35 may be provided for the lower end of the member 34.

In our companion application filed April 20, 1926, Serial No. 103,189, we have described and claimed broadly a fire extinguishing system wherein the outlets for the extinguishing medium in the fire zone are thermally controlled by suitable construction of thermostat and are normally closed while the means for supplying fire extinguishing medium to the piping leading to the outlets is itself under the control of an independent thermostat more sensitive than the thermal means for the outlet and comprising a thermostat operated by comparatively quick rate of rise of temperature, the organization being such that the said supply means are normally inactive but, under the control of their thermostat are called into action in advance of the opening of the outlet under its own thermal action and we do not therefore, claim such an organization broadly in the present case.

What we claim as our invention is:-

1. In a dry pipe fire extinguishing system, a valve controlling the supply of fire extinguishing fluid to the system responsive to decrease of normal air pressure in the system due to the opening of an outlet for causing said valve to operate and means for operating said valve upon sudden or abnormal rate of increase of the air pressure due to heating of the same in the distributing system.

2. In a fire extinguishing system containing air under pressure, the combination with a valve controlling the supply of the extinguishing medium to the system and responsive to a drop in pressure in the system for causing said valve to operate, means responsive .to a rapid increase of air pressure due to increase of temperature at an abnormal rate in the area to be protected for bringing said valve into operation.

3. 'In a fire extinguishing system, the combination with a valve controlling the admission of a fire extinguishing medium to the system and normally held closed against the pressure of the fluid supply by the normal pressure of fluid in .the system and'means responsive to a sudden or abnormal rate of increase of the pressure in the system due to heating of the same for disturbing the balance of pressures on said valve to cause the same to open.

4. In a fire extinguishing system, a distributing pipe for the fire extinguishing medium, a differential automatic main valve, held normally closed by the pressure of air in the distributing pipe a chamber wherein pressure tends to unseat the valve and means for automatically admitting air pressure to said chamber upon sudden increase of air pressure in the piping extending from the area to be protected to the main valve.

5. In adry pipe fire extinguishing system, the combination with a main valve having an atmospheric drip chamber and provided with an automatic check in the drip outlet, of means for automatically admitting air under pressure to said chamber, said means comprising pressure responsive means subject to the force of expansion of air abnormally heated in the distributing system to expedite the opening of the main valve.

6. The combination with a main fiuid supply valve, of means for applying unseating air pressure thereto through the controlling action of an air pressure responsive device a chamber containing air under pressure acting on said pressure responsive device, means for supplying air to the chamber carrying air pressure acting on said pressure responsive device, and means for automatically locking said pressure responsive device out of action while the means for supplying air are acting.

7. The combination with the main fluid supply valve, of a supplemental valve through which air pressure is supplied to unseat said main valve, a pressure diaphragm controlling the action of the supplemental valve, means for restoring air pressure in the chamber containing said supplemental valve, a restricted bypass connecting the spaces in which pressures act oppositely upon said diaphragm and means for locking the diaphragm and its connected controlling devices subjected to pressure from said restoring means. 8. The combination with the main fluid supply valve, of a supplemental valve for applying pressure to unseat the same, a pressure diaphragm controlling the action of the latter valve, a chamber containing said latter valve and normally containing air acting on one side of said diaphragm, means for supplying air under pressure to the chamber containing said valve to replenish the same, a restricted bypass connecting said chamber with a chamber on the opposite face of said diaphragm and means subjected to the pressure of the air supply for holding the diaphragm and its connected controlling devices out of action While the air in the chamber is being replenished.

9. The combination with the main distributing pipe containing air under pressure, the main supply valve having a chamber and means connected therewith whereby air pressure in said chamber may act to cause the valve to be unseated, a valve controlling the admission of air under pressure to said chamber, a diaphragm subject to variations of air pressure in the main distributing pipe of the system and having a bypass leading from the space on the side of the diaphragm subject to such variations of air pressure to a space in which the air acts with an opposing pressure, means connected with said diaphragm for opening the latter valve, a pump for restoring the air pressure in the pipe system and having communication therewith through the chamber carrying said diaphragm, a supplemental chamber containing a supplemental diaphragm operatively associated with said diaphragm subject to the variations of air pressure, a valve through which the pump is connected with the pipe, means connected with the supplemental diaphragm for opening said last mentioned valve, and means carried by thelatter diaphragm for locking the said valve operated diaphragm means out of action during the replenishing of the air supply.

10. The combination with the main valve of a fire extinguishing system, of means subject to variation of pressure in a chamber, means controlled by said pressure responsive means for supplying air under pressure to unseat the valve, means for restoring the pressure in the chamber of said pressure responsive means, locking means locking said pressure responsive means out of action by the pressure of the replenishing air supply and means for automatically holding said locking means in looking position under the action of the increased pressure in the chamber of the aforesaid pressure responsive means.

. pressure restoring air to lock the pressure responsive diaphragm out of action and means connected with the latter for holding the locking mechanism in looking condition when the pressure responsive diaphragm responds to the replenished pressure.

12. The combination of a supply pipe for a fire extinguishing medium, a main valve for the supply pipe, a pressure diaphragm subject to variation of normal air pressure in the main supply pipe, mechanism connected therewith for operating an air valve, means for restoring the normal air pressure, a supplemental air pressure diaphragm subject to the pressure of pressure restoring air, means connected with the latter diaphragm for locking the valve operating mechanism out of action and means connected with the firstnamed diaphragm for locking said mechanism in looking position.

13. In a fire extinguishing system, the combination with distributing piping containing air under pressure and subject to heating effects in the fire area or zone, a main valve controlling the admission of fire extinguishing fluid to the distributing piping, control mechanism for said valve, and a weighted actuating device for said control mechanism, said weighted actuating device being normally detained or held out of action and means responsive both to decrease of air pressure and to increase due to heating of air in the fire zone for releasing said weighted actuating device on movement of said responsive device in either direction.

14. In a fire extinguishing system, the combination with air tubing containing air under pressure and extending from the fire zone or area to a point of control, a weighted actuatin device normally detained or held out of action, a diaphragm subject on the one side to direct pressure of air from said tubing and on the other to an opposing or indirect pressure derived through a restricted bypass around the diaphragm and means connected with said diaphragm for releasing said weighted actuating device upon either increase or decrease of the air pressure in said tubing.

15. In a fire extinguishing apparatus, the combination substantially as described of a main valve, a control valve controlling pressure upon said main valve to effectuate an opening thereof, piping extending from the fire zone and containing air expanded byheating efiect in said zone on the occurrence of fire, a diaphragm subjected on the one side to a direct pressure of air therein, a restricted bypass around the diaphragm for applying pressure to the opposite side of said diaphragm and means controlled by said diaphragm on either rapid increase or decrease of the normal pressure in the air piping for eifecting the operation of said control valve.

16. In a fire extinguishing system, the combination with air tubing containing air under pressure and extending from the fire zone or area to a point of control, a weighted actuating device normally detained or held out of action, a diaphragm subject on the one side to direct pressure of air from said tubing and on the other to an opposingor indirect pressure derived through a restricted bypass around the diaphragm and means connected with said diaphragm for releasing said weighted actuating device upon sudden increase of the air pressure in said tubing.

1'7. In a dry pipe extinguishing system, the combination with a supply valve, normally subject to fluid pressure in the system of a supplemental chamber wherein pressure of fluid tends to unseat the supply valve, means operated by the force of sudden expansion of heated air heated in the area to be protected and means controlled thereby for admitting fluid under pressure to said supplemental chamber to cause the supply valve to open.

18. In a fire extinguishing system, the combination with a control valve controlling the supply of fire extinguishing medium to the system, means subject to pressure of fiuid in said system and acting on said valve in a direction to hold the same closed and subject also to a decrease of the pressure therein due to the opening of an outlet and pressure responsive means responsive to the force of expansion of a confined body of air due to sudden heating of the air under fire conditions for causing said valve to open.

19. In a dry pipe fire extinguishing system, the combination with a differential automatic water supply valve for the system subject to variation of pressure in the system consequent upon the opening ofan outlet of the system in the area to be protected and means subject to the sudden force of expansion of air in the fluid distributing system due to heating in the fire zone and means controlled thereby for producing on a face of said valve a pressure which will cause the same to open.

20. In a fire extinguishing system, the combination with a pipe for carrying the fire extinguishing medium to the outlet, a difierential valve in which the normal pressure of air in the pipe holds the same closed, and means for admitting air pressure to a chamber of said valve in which the pressure will tend to unseat the valve, said means comprising a control valve normally shutting oil the flow of air under pressure to said chamber, pressure responsive means in communication with the pipe responsive to sudden increase of pressure due to heating under fire conditions.

21. In a fire extinguishing system, the combination with a differential valve normally held closed by pressure of gas in the system, a chamber connected with means for causing the valve to become unseated by the action of pressure in said chamber, means for admitting fluid under pressure to said chamber comprising a valve normally closing the entrance of fluid to said chamber, pressure responsive means connected to the system and means controlled therefor actuating said valve said pressure responsive means being responsive to pressure generated at a greater than a predetermined or adjusted rate by heating of said air in the fire zone.

22. In a dry pipe fire extinguishing system, the combination with a difierential main valve controlling the supply of fire extinguishing medium to the system and having an atmospheric drip chamber provided with an automatic check in the drip outlet, of means actuated by the force of expansion of a confined body of air when heated for automatically admitting air under pressure to said chamber when said body of air is abnormally heated and expanded in the fire zone to cause said main valve to open.

23. In a dry pipe fire extinguishing system, the combination with a main valve having an atmospheric drip chamber and provided with an automatic check in the drip outlet, of means for automatically admitting fluid under pressure to said chamber said means comprising a pressure responsive means subject to the force of expansion of air abnormally heated in the distributing system to expedite the opening of the main valve.

24. The combination with a main difierential valve for a dry pipe fire extinguishing system, of

a supplemental air chamber in which pressure of air acts on the main valve in a direction to tend to unseat said valve, a chamber connected directly to the dry-pipe of the system and having pressure responsive means responsive to pressure generated by heating of air at an abnormal rate in the fire zone, a valve controlling a connection between said chamber and the supplemental chamber of the main valve, a lever for opening the said connecting valve and means connected with the pressure responsive device for actuating said lever upon movement of said responsive means in either direction.

25. In a fire extinguishing dry pipe system, the combination with the main valve, of a supplemental chamber for applying pressure tending to unseat the same, a valve controlling the flow of fluid under pressure to said supplemental chamber, pressure responsive means connecting with devices for opening the latter valve in response to an increase of fluid pressure acting therein, means connecting said pressure responsive means with the main pipe of the system, said pressure responsive means being provided with a pressure modifying vent by which pressures on the same may be equalized, said vent serving to delay the establishment of an equalized pressure when the pressure in the main pipe rapidly increases.

26. In a dry pipe system having a piping containing a confined body of air under pressure, the combination with a main valve, means for supplying unseating fluid pressure to said valve through a normally closed supplemental valve, pressure responsive means subjected to the force of expansion of the confined body of air in the piping of the system and subject to abnormal temperatures in the fire zone and a lever connected therewith and having two actuating members acting upon suitable devices to cause the supplemental valve to open upon response of said responsive means to the change of normal pressure above and below normal and due respectively to abnormal heating of the air in the fire zone and to opening of an outlet connected to the piping.

ERNEST A. LOWE. JOHN R. HAMILTON.