US2099069A - Fire extinguishing and alarm apparatus - Google Patents

Description

Nov. 16, 1937. E. A. LOWE ET AI. 7 2,099,069

FIRE EXTINGUISHING AND ALARM APPARATUS Filed Dec. 15, 1951 v Sheets-Sheet 1 ATTORNEYS Nov. 16, 1937.

Filed Dec. 15, 1951 7 Sheets-Sheet 2 INVENTORS Er]? est A Lowe J fin Rfi amz'lion/ -ATTORNEYS Nov. 16, 1937. E. A. LOWE ET AL 9 FIRE EXTI NGUISHING AND ALARM APPARATUS Filed Dec. 15, 1931 7 Sheets-Sheet 3 ATTORNEYS Nov. 16, 1937. E. A. LOWE ET AL FIRE EXTIN GUISHING AND ALARM APPARATUS Filed Dec. 15, 1931 7 Sheets-Sheet 4 Lave.

(fall I Nov. 16, 1937. E; A, L WE ET A 2,099,069

FIRE EXTINGUISHING AND ALARM APPARATUS Filed Dec. 15, 1931 7 Sheets-Sheet 5 inn-- Q INVENTORS l'rnestd Lou/e ATTORNEYS N 1937. E. A. LOWE ET AL I FIRE EXTINGUISHING AND ALARM APPARATUS 7 Sheets-Sheet 6 Filed Dec.- 15, 1931 NwN ma f 0 wim Tfl Jr N N a R Et 0 V s Nov. 16, 1937. E. A. LOWE ET AL I FIRE EXTINGUISHING AND ALARM APPARATUS Filed Dec. 15', 1931 h INVENTORS Ernest A Lowe B viz/21215702171211 ATTORNEYS Patented Nov; 16, 1937 UNITED "STATES PATENT OFFICE FIRE EXTINGUISHING AND ALARM APPARATUS corporation of Delaware Application December 15, 1931, Serial No. 581,088

36 Claims.

This invention relates to improvements in automatic sprinkler and alarm mechanism.

It is a primary object of the invention to provide a system of this character of universal application such that it can be applied to any usual type of structure to be protected and which will .operate uniformly under any normal temperature or other atmospheric conditions' It is a further object to provide a mechanism of this character which will require a minimum of attention on the part of any attendant, and wherein the elements of the mechanism are so arranged, supported and related as not to becomeinjured orbtherwiseout of order when in use. l

The above and other objects will appear more fully from the following description when considered in connection with the drawings in which:

Fig. 1 is an elevational view, parts being in section, and illustrating one complete adaptation of the present invention.

Fig. 2 is a fragmentary perspective view of a group of the elements placed in a fire zone.

Fig. 3 is an enlarged vertical sectional view of one of the heat absorbing pressure producing elements constructed in accordance with our invention.

Figs. 4 and 5 are transverse sectional views of two forms of tube supports shown in Fig. 2.

Fig. 6 is a vertical sectional view through the main fluid supply valve and control unit therefor.

Fig. '7 is a vertical sectional view, parts being in section, of a portion of the control mechanism and illustrating the general relation of the release elements employed.

Fig. 8 is a horizontal fragmentary sectional view of the load supporting levers of the release.

Fig. 9 is a fragmentary sectional view of the diaphragm and housing and the associated escapement levers.

Fig. 10 is a sectional view on the line |0I0 of Fig. 9. g

Fig. 11 is a horizontal sectional view of the manual reset lever employed.

Fig. 12 is a diagrammatic view illustrating the heat absorbing. units placed in the difierent fire zones and the associated flow controlling units leading to the main pressure responsive device of the mechanism.

Fig. 13 is a vertical section view illustrating the manual gate valve operating shaft and the alarm valve controlled thereby.

Fig. 14 is a vertical sectional view of the float chamber and valve controlling mechanism for automatically maintaining a substantially constant pressure in the distributing pipes and supplemental tubing.

Fig. 15 is a view similar to Fig. 14 but taken 5 at right angles thereto.

Fig. 16 is a vertical sectional view through the air filter shown in Fig. 1.

Fig. 17 is a perspective view of the separated valve controlling elements controlled by the float and serving to operate the air injector and alarm.

Figs. 18, 19 and 20 are elevational views 01' the float actuated valve operating weights illustrating three adjusted positions of the parts.

Fig. 21 is a fragmentary detail view of. the fire alarm gong and siren employed.

Referring to the details of the drawings wherein there is illustrated a preferred adaptation of our invention, the main fluid supply pipe 24 for supplying fire extinguishing fluid under pressure is provided with a manual gate valve 25 and' with an automatically controlled main supply valve 26.and automatically removable pressure retaining or check valve 23. The fluid supply is conducted from the source to the risers 21 and branch pipes 28 leading to the different flre zones. -A separate or auxiliary water supply is shown at '29 for supplying fluid to operate the alarms, etc. in case the source at 24 should fail.

The gate valve 25 is controlled by means of the hand wheel 30 and valve operating shaft 3| (Fig. 13) placed within the yoke 32. The shaft 31 as shown in detail in Fig. 13 is formed with a recess 33 for receiving the operating end of a valve lever 34 when the shaft is in closed valve condition. The lever 34 controls a valve 35 for admitting water or other fluid from the pipe 36 leading from a suitable source of supply as for instance fluid supply pipe 24 below the gate valve to the pipe 38 communicating with the pipe 39 and with the alarm 40 shown as a siren operated by a fluid motor 40a. The pipe 36 communicating with the supply pipe 24 has also a communication with the pipe 31 leading from the auxiliary source 29 the latter source being thus available to operate alarm in case the source 24 should fail. The mechanism associated with the gate valve 25 serves to operate the alarm, siren or signal 4 0 at all times the gate valve is i in other than full open position. Said signal 40 is operated by a fluid motor supplied from pipe 39 and actuating motor driving wheel 40a all mounted in a suitable enclosure as shown. A suitable check valve as shown prevents the water from source 24 -from"backing up into pipe 29.

There is also provided an electrically actuated alarm 43 adapted to be placed in closed circuit conditionwitl'i itslsource of power '44 when the lever 34 is moved to position to open the valve 35. This is accomplished by providingthe normally open contacts 45 in position to be engaged and closed by the lever 34 when the latter moves to position to open the valve 35. -An operation ofthe gate valve control wheel 31B thereby actuates the water actuating siren 4t and also the electric alarm 43. Hence, if the water operated alarm 40 should fail to sound for any reason when the gate valve is closed as forinstance through failure of water supply to said alarm, nevertheless a signal of the closure of said valve will be given on the electric alarm The particular construction of device and the manner of operating the same from the gate valve stem are not herein claimed as they form the subject of our application for patent filed August 31, 1932, Serial No. 631,132. 7

An electric alarm M may be provided and controlled by a switch 42 operated by a pressure responsive diaphragm, the latter communicating with the pipe 39 to cause the alarm iii to be actuated at any time water pressure is supplied to the piping 3%. By this means an alarm will be given in case the fluid operated devices: for actuating the alarm 40 should fail to function under the pressure aiiorded by pipe 39.

There is also provided an electric alarm 6!, controlled by a switch 62 operated by a flexible diaphragm which communicates with the pipe 56 for actuating this alarm coincidently with the fire alarm 55.

The main fluid supply valve 26 is formed with a valve chamber 46 for receiving the valve clapper 41 which serves when closed to shut off the fluid supply between the source 2d and the risers and distributing pipes 2'0 and 2a. valve closure 41 is of a known type and includes the inwardly bent facing 48 cooperating with the valve seat 49 for effectively sealing the valve when closed. The valve is held in closed position by means of a latch 50 pivoted to the valve casing at 5i and provided with an extension 52 extending through the opening 53 leading from the valve chamber 46 to the exterior air into position for operation by hammer blow impact of a weight 64 as will be presently described. The latch 50 is provided with an outwardly opening sealing washer 54 cooperating with the valve seat at the opening 53 to close this opening when the latch 50 is moved to unlatched position.

It is preferred to associate a second fire gong or signal 55 with the apparatus constructed to be operated by the main water pressure supply. The gong 55 has a fluid actuating motor as indicated similar to the fluid operated motor and alarm 40. Each alarm 40-55 is operated separately by its own driving fluid motor or driving wheel. and both are mounted in one enclosing casing as shown, one of said gongs or alarms serving for operation in connection with the gate valve while the other is used as a fire alarm signal or gong which will'sound whenever the main valve opens in response to fire conditions in the fire area to be protected. The fluid motor of this fire: gong is connected by the pipes 56 with the chamber 46 1 of the control valve so as to provide water pressure in the piping 56 for creating an alarm at all times the main supply valve is in open condition. Pressure may be supplied by opening the The manual valve 51 for testing the apparatus when desired. The second signal 55 and its fluid actuated motor are mounted as shown in the same enclosure with signal 40 and its motor to form a single unit having the two protective signals-each fluid operated by fluid pressure derived from the desired source.

There is also provided an electric alarm 4! controlled by a switch 42 operated by a flexible diaphragm which communicates with pipe 56 for 10 actuating said alarm coincidently with the fire alarm 55 when themain supply valve opens. I

By this means we insure .the giving of a fire alarm in connection with the opening of the main valve even though the water supplied to .the gong 55 should for any reason fail to bring about the action of the gong operating motor.

As will be presently described we further insure the sounding of a fire signal whenever the mecha= nism controlling the fluid supply is brought into operation automaticallyby the pressure responsive release devices, through the provision of a circuit controller operable by a releasable weight released in the operation of causing the main valve or other fluid supply to become operative.

The release mechanism indicated generallyat 58 is provided for the purpose of moving the latch 50 to unlatched position and is constructed to be actuated on either an increase or decrease of pressure in the supplemental tubing. The re' lease box 59 carrying themain operating elements or the release is placed within a sealed chamber 60 having an outer casing 6i and closure plate $2. The sealed chamberor enclosure St for the main operating elements of the release and for the feed ends of the supplemental tubing it (see Figs. 1, 6 and 12) has an unsealed chamber or housing 63 for receiving and housing operating weight 6d and associated parts.

The pressure responsive device 65 (Fig. 9) includes a diaphragm 66 mounted within a. chamber 68 in the diaphragm casing 89. The diaphragm chamber 68 formed between the upper and lower cases 10 and II has two concave inner walls to. permit the diaphragm to move toward either side from the central neutral position in which it normally remains. It is preferred to employ two supporting plates I2 and 13 to reinforce the diaphragm at its center near the opening leading to the passage Him the upper case for conveying pressure to the diaphragm and near the opening in the lower case in which the diaphragm plunger 15 is loosely mounted.

The vent 16 mounted in the upper diaphragm case 10 and communicating with the passage 14 is employed 'to gradually equalize the pressure in the supplemental tubing and on the upper face of the diaphragm 66 and supplied from chamber 60 with the pressure contained in the said chamber 60 (Fig. 6) and determines the rate at which the pressure in the tubing must rise or fall in order to become effective in moving the diaphragm to effect a release. The vent comprises a a relatively small tube 18 (Fig. 9) filled with the supplemental tubing from the sealed casing 60 which is supplied with air under pressure from an air injector I84 as will be presently described. The air injector also has an air filter 220 interportingfinger of the latch is, the weight with posed in the air connection to the casing 68 and of a construction which will be described further on.

The plunger I5 is attached to the diapragm 66 and to the escapement lever 8i as shown so as to transmit movement of the diaphragm in either direction into corresponding movement of the escapementlever. The lever 8| is normally retained in its central neutral position as shown by means of the tension spring 82. The lever M is formed with an angular projection 83 having a flat surface engageable edgewise against a corresponding projecting finger 84 formed on the escapement lever 65 held in place against the projection 83 by a spring 85'. with this construction movement of the lever 8| in either dilocated in the outside chamber or housing 68 and with an operating pin 9I positioned in a slot 92 formed on the release operating-lever 94 within the sealed chamber 68. The lever 94 is carried by a rock shaft 95 for movement therewith, the shaft 95 being also providedwith a weighted lever 96 for returning the shaft 95 to its normal position as shown in Fig. 6.

The resetting lever 91 secured to the shaft I I! which carries lever II6 (see Fig. 7) and releases 94 (see Figs. 8 and 11) is formed with a slot 98 for receiving an operating finger 99 of the outside'manual release lever I88. The-lever I88 carried by a transverse pivot pin IM and sealed with respect to the interior of the casing 6| by means of a rubber or other diaphragm I82 is movable about the axis of the pin I8I for moving the resetting lever 91 to resetting position through an upward movement of the handle I 88.

The weight 64 (Fig. 6) is movably supported and reciprocates vertically on a guide shaft I84 outside the release box 59 mounted in the unsealed protecting housing or chamber 63 which is suitably formed to allow access to the weight for moving the same by hand or otherwise independently of the means for automatically releasing the weight. The guide I84 is pivotally connected at its lower end to the latch lever extension 52 and is supported for vertical movement at its upper end by a guide I85 mounted independently of the weight guide. The weight when released creates a hammer blow on the latch lever extension 52 for unlatching the latch 58, thus bringing about the opening of the main valve.

The weight 64 releasable and adapted when released to fall and strike the latch extension 52 is sustained in lifted position shown by means of a tiltable weighted latch lever I86 which is pivotally connected at I81 to the weight 64 and is biased by depending weight I86 on said latch lever so that when the weight is restored to latched position it will assume position for weight supporting engagement with the main release lever. The latch lever I86 is formed with a supporting finger I88 engageable with the supporting projection .98 of said main release lever 86- to normally sus- I r lease device in box 59. thus freeing the sup:

the attached latch will fall. The latch lever I86 is also formed with an upwardly projecting finger or lug I89 normally engaging a detaining device consisting preferably of a'slide bolt 8 5 for normally preventing tilting movement of the latch lever under the influence of the weight in a direction to free it from the supporting projection 98 of the main release lever 88. The detaining device or slide H8 is removable from de- 10 taining position by any desired means as for instance by means of the lever I II and pull I I2, said lever being connected with the slide I I8 as shown or in any other suitable manner. A coil or other spring acts on the bolt to normally hold it down 15 in detaining position. The bolt might be operated also by a cable I I3 extending from any convenient position where it maybe operated by a pull to lift the bolt. When the slide or detaining device is removed from such detaining position, 28 the latch is free to be tilted by the influence of the weight 64 to which it is pivoted thus permitting the weight supporting finger I88 to slip by the projection 98 without movement of the release lever 86 which may at such time be in locked 25 position. The weight 64 is accessible through the wall of the-housing so that it may be lifted and restored to position for being latched up until released by the action of the release lever 86. The mounting of the weight 64 and its attach- 30 ments in a suitable housing or casing outside the sealed enc osure or box 59 and its operating elements facilitates the operation of resetting and supervision of action of the weight and attachments and also contributes to ease of installa- 35 tion of the apparatus. a

An alarm or signal is provided whereby a signal wi l be given whenever the weight is dropped either through operation of the automatic release 86 or by the manually operated means III or 48 I I3 acting on the slide or detaining device I I8. A convenient means for operating such signal oomprlses an electric switch and electric alarm bell controlledthereby. A form of switch adapted to function and sound the alarm or signal when the weight falls or is released comprises switch contact 51 spring pressed towards closed position and normally held in open position by means of a switch finger engageable by the weight 64' when in sustained position. The switch when closed on movement of the weight due to release thereof either by the automatic release lever 86 or by operation of the slide or detaining-device- Il8 is employed to close the electric circuit through an alarm bell 51 and suitable source of current supply. By means of the weight controlled'circuit controller and aarm 51 we insure the giving of a signal or alarm although either or both the alarms 55 and M controlled or operated by fluid taken from the main valve chamber 26 should for any reason'fail to operate, or if there should be failure of the main supply 24 or of the main valve 26 to operate thus opening the supply of fluid for operating said alarms 55 and H. a

The release elements in box 59 (Fig. 6) operatively connected between the escapement lever 85 and the main release lever 86 (Fig. 8) for controlling the latter through movements of the former include the release operating lever 94, referred to above, and which is rigidly attached to the shaft 95. The free end I I4 of the lever 94 engages beneath a'shoulder II5 formed on the locking lever II6 (Fig. 7) the latter being pivotally mounted on the resetting shaft III which is free end II6 of the lever I I6 normally engages against the rearward cylindrical surface I20 constituting a keeper formed on the milled end of the hub or supporting shaft I2I of the operating lever I22. The projecting end I20 of the shaft IEI adjacent the surface I20 is formed with a milled end I23 to permit the lever end II8 to pass the same when the stud I2I is rotated to the proper position. The lever H6 is provided with a resetting pin I24 secured to the same and projecting through a slot I25 formed in the supporting plate I26, the slot accommodating the'maxi-' mum movements of the lever IIIS when moved between normal and released positions.

The lever I22, formed integrally with or securely attached to the shaft IN, is formed with a weighted end I26 which tends to rotate the lever in a counter-clockwise direction as viewed in Fig. '1 and with an angular arm I26 provided with a pin I66 cooperating with the resetting devices of the release referred to below. The locking end iii of the lever carries a pivotally mounted lock-, ing pawl I32 which in cooperation with a suitable ratchet sustains the lever I22 in the position shown in Fig. '1. The pawl I3? is movable in a clockwise direction (as viewed in Fig. '7) to a limited extent only wherein it engages a stop pin I31, being normally held in engagement with the pin by means of a spring I36. The pawl I32 is movable in a counter-clockwise direction to permit the locking end I35 formed on the pawl to move past the retaining portion of the ratchet device. The ratchet device includes a rotatable spindle I38 formed with a ratchet tooth I38 engageable by the locking end I55 of the pawl when the parts are in their operative positions. The escapement lever I40 which controls the ratchet device is attached to the spindle I36 to cause the lever I65 and spindle I36 to rotate together. The outer movable end of the escapement lever is formed with an angular extension I (Fig. 9) positioned to be engaged by the cam-shaped finger I42 formed on the escapement fulcrum lever 85.

The supplemental tubing for conveying the pneumatic impulses from the various fire zones to the ,pressure responsive diaphragm 65 comprises the tubing I44 (Fig. 12) extending from the heat absorbing units I46 in the fire zone to the flow controlling units I48 and the tubing I49 connecting the various units I48 with the pressure responsive device 65. The units I48 are mounted within the chamber 60 adjacent to the hinged door I50 (Fig. 6). The units may be mounted directly on the casing 6| or on the door I5Il (see Fig. 6), the purpose being to surround the units I48 with the pressure in the chamber 65.

Each of the units I48 is formed with two seallng chambers I5I andI52 (Fig. 12). Chamber I5I communicates at its upper portion with the tubing I49 leading to pressure responsive device 65 and at its lower end' is sealed by means of a tube I53, the lower end of which is immersed in a sealing liquid (mercury) I54. The tube I53 ber 60, the tube I55 having its lower end immersed in the liquid (mercury) I56 and opening at its upper end in the chamber 60. The tube I55 extends vertically above the liquid I56 to an extent sufiiciently to effectively prevent the passage of pressure from the chamber I52 through the tube I55 into the chamber 60 for any usual pressure to which the apparatus will be subjected in use, the enlargement I51 thereon .being suflicient to receive andhold the liquid I56 in case the liquid should he accidentally forced through the tube I55. The lower end of the tube I 55 is immersed only to a'slight extent in the liquid I56 so that pressure passes readily from the chamber 66 inwardly through the tube I55 to the chamber I52 and thence to the tubing I56. or to the chamber I5I and tug I49.

The tubing I53 is preferably of a height for maintaining suflicient pressure in the chamber I5I to flex the diaphragm 66 and operate the release, the necessary margin of safety being provided. Any excess pressure in the tubing Ilt and chamber I5I forces the mercury I5 3 upwardly into the chamber I52 where it remains until the increased air pressure at I52 ceases after which 'the mercury again passes downwardly through the tube I 53 and eilectively seals the lower end of this tube as shown in Fig. 12.

Each of the sets of heat absorbing elements I56 is placed in a separate fire zone and due to -the sealing efiect of the tubes I56 and I55 the pneumatic impulse in any set of heat absorbing elements I i6 and tubing I66 from any fire zone is conveyed directly to the diaphragm 66 at least to an extent sufficient to actuate the re lease since the tubes I53 are immersed only slightly in the liquid I 55 yet the vertical height of other tubes I53 is sufiicient to create a release operating pressure.

Briefly, the system. operates as followsz-after closing the entire system at atmospheric pressurel lb. pressure above atmosphere is impressed on the inleading air pipe to enclosing casing (this 1 lb. pressure passes by flap check valve in air pipe) and into casing 66. It is free to pass seal I56 and I56 into tubes I lt, heat devices M6 and tube M9 and space 68. Vents 16-16 relatively assist in passing this pressure as above described; after a period of time the 1 lb. pressure is equal in tubing Ida-455 and chamber 66,

thus being balanced equally on both sides of diaphragm 66.

Vents 16 and-l6 are adjusted to equalize difference in pressure between chamber 66 and thermal system I44I49I46 due to local temperature fluctuation in region of I 46 before such difference in pressure reaches the critical operating point of 66 and 8i.

Fire in region of Hi6 produces an abnormal pressure in I44 exceeding the equalizing adjustments of 16 and 16', and being stopped from loss to chamber 60 by tube I55 and seal I56 is free to pass seal I54 into tube I49 and chamber 68-moving diaphragm 66--operating detent 8i.

This fire pressure is checked against loss to other tubes by tube I53 and seal I54, and also by vent 16; critical operating point of detent 8! is reached before I56 and I55 permit such fire pressure to escape into chamber 60.

Should a break occur in I44 or' I46, this would allow the 1 lb. pressure in I44 or I46 to'escape to atmosphere, creating an impulse in I49-I44 moving in the reverse direction than that from fire impulse since the brealg lowers the pressure in I44I46, and 'seal I54 permits the higher pressure in I49 and 68 and other connected tubes I44 to freely pass and discharge out of the broken tube I44, seal I56 andvents 16-16 being sufiicient to check against the higher pressure in 60 escaping, except by slow equalization wardly due to the temporarily retained higher pressure in chamber88.

A break in the enclosing case around cham-' ber 68 permits escape of pressure in 68, lowering such pressure and moving diaphragm 68 outwardly to operate detent 8| by reason of the higher pressure being retained in I44-I46-I49; tube I55 retains this higher pressure up to and safely beyond operating point of diaphragm 66 and detent 8|.

Through the use of the units I48 the normal pressures developed in the tubing leading from any. fire zone are equalized with the pressure in the chamber 68 through the restricted vent 16. When any abnormally high pressure develops-in the tubing I44 or I49 it is permitted to escape through the tubes I53 and I55 in order to prevent damage to the tubing or its asso' ciated devices under abnormal conditions and after the operation of the release.

The heat absorbing units I46 each comprise a casing I58 (Fig. 3) connected to tubing I44 and mounted adjacent the ceiling of the room on a bracket I59. The units are preferably mounted within the skeleton framework I68, the two halves of which are latched together as at I6I, the upper half being secured to an. attachment plate I62 formed with a hooked end I63 secured within a recess in the bracket I59.

Each unit I48 is provided with an automatic device for opening the interior of the casing to the outside air on the attainment of a fixed relatively high temperature. In the present embodiment this device comprises a sleeve I64 permanently mounted at the lower portion of the casing I58 and receiving a sleeve nut I65 having an opening at its lower end corresponding to the ment I1I engageable against the upper end of the sleeve I64 when the tube falls to prevent the tube from dropping completely out of the casing, the tube being normally sustained in the elevated position shown by means of the fusible washer I66. The lower portion of each tube I69 is preferably painted some bright color as red or white so as to be readily seen and distinguished from the unit proper when exposed.

The pressure conveying tubing I48 is prefer ably supported on the distributing pipes by means of the novel supporting devices disclosed herein which include a series of clamping elements I12 (Figs. 2 and 4) comprising C-shape-d bands I13 each having an opening I14 suiflciently large to receive the particular size of distributing pipe 28 on which it is supported. A space is provided at one end of each band for receiving a channelled wedge-shaped securing element I15 received over the tubing I44 and constructed to be wedged between the end of the member I13 and the pipe 28. The elements I15 provide guiding channels having suflicient space for loosely receiving and holding in position a section of the supplemental tubing. The adjustable strap I131: may be used in place of the C-shaped band I13.

In some'portions of the apparatus the tubing may be supported in suitably attachedv brackets I16 provided with'an aperture or with a slot for receiving the tubing. In other portions of the apparatus the tubing is supported by having v v I 9,099,009 Q to the break so that diaphragm 66 moves in-"- Y porting hanger I13.

The supplemental tubing is protected adjacent the sprinkler outlets I 18 by means of the inverted cupped guards 118, each formed with an attachment portion I88 and with an outer flanged edge I8I which extends semi-circumferentially around the axis of the sprinkler outlet to provide an inverted pocket I82 for receiving and protecting the tubing.

Pressure is automatically maintained in the distributing pipes and supplemental tubing by means of the air injector indicated generally at I84 (Fig. 14). In our preferred construction we employ an air pressure supply consisting of'a water operated injector or inspirator acting on the Venturi principle, wherein the water necessarily comes into contact with the air so that the air tends to become laden with moisture. The form of such injector or inspirator I84 herein shown comprises a float chamber I85 and a liquid chamber I 86, the latter having a relatively greater height compared with the float chamber I85. The two chambers communicate at their lower ends as indicated at I88 and the liquid chamber I86 is provided with an overflow outlet I89 at its upper end. Air is supplied to the pipes and tubing by means of a water actuated air injector 288. and admission valve 284 therefor controlled by a float I98 positioned in the float chamber I85 and weighted as indicated at I9I in order to provide the necessary weight. The float is loosely mounted on a hollow control shaft I92, being limited in its movements with respect to the shaft by means of the stops I96 and I94. The shaft I92 is guided in its movements by means of a lower guide rod I95 positioned within the shaft I92 and connected to a removable plug I96 attached to a lower wall of the float chamber.

The upper end of the shaft I92 is pivotally connected to an arm I91 of the operating quadrant I98 mounted for pivotal movement on the transverse shaft 288. This quadrant carries two operating pins E9 and A1; one on each face thereof, the pin Ep coacting with the limit pins E2 and E1 positioned on the shlftable ejector actuating weight E and pin A coacting with the pins A2 and A1 on the shlftable alarm actuating weight A. The weighted elements E and A are formed with openings E0 and A0 for receiving one of the operating sectors I99. These sectors are each formed the .wedge shaped T I18 received within the sup- 5 with an arcuate section 28I received within the openings E0 and A0 and terminating in engagement fingers 282, the fingers being engageable by the weighted members E and A when the latter are moved beyond their dead center in one direction or the other. The sectors I99 are formed with the operating fingers 283 operatively connected with the fluid control valves 284 and 285. These valves are of a known type and each includes a shlftable element 286. (Fig. 20) movable to or from closed valve position by means traina quantity of air with the liquid passing into the chamber I85. The air and liquid separate bygravity in the chamber I85 thus gradually building up the air pressure in the upper portion of the chamber and lowering the liquid level at the float I90. The excess liquid overflows at I 89 leading to the drain outlet and the air passes by outlet pipe 2I5 in the upper portion of the chamber I85 through the drier and filter 220 and pipes HI and 222 to the sealed chamber 60 and the supplemental or pressure conveying detector tubing I44 with its moisture picked up in the inspirator removed. The pipe 2I5 also connects to the distributing pipe by a pipe '2I6 to maintain definite pressure therein from.the air chamber I85 of the injector.

The valve 205 controls the admission of water irozn a branch of pipe 201 which communicates through the valve with a pipe 2I2 (Fig. 1) leading to the pipe 39 which in turn leads to the water motor 40a of the siren 40.

'The pins E and Ap and the coasting pins E2, E1, A: and A1 are coordinated with respect to the axis of the shaft 200 (see Figs. 17 to 20) so that weightE is shifted to operative (valve open) position when the fioat I80 has risen to substantially the level b (Fig. 15). On a further rise of the float to approximately the level 0 the weight A is moved beyond dead center to its operative position for supplying power through the valve 205 for actuating the alarm 40.

The various conditions of operation of the quadrant I88 are indicated in Figs. 18, 19 and 20. In Fig. 18 the float is assumed to be at the level a in the float chamber (Fig. 15) and the maximum pressure is present in the chamber me. As the pressure decreases. the water passes from the liquid chamber use into the float chamber 835 thus raising the float and causing a corresponding clockwise movement oi the operating uad-= rant tilt. As the arm is? is raised the pin E first engages the pin E1 on the weight E. Further upward movement oi the float throws the weight E beyond dead center thus shifting the valve 2% and turning on the liquid for actuating the air inspirator. This condition of the weights is indicated in Fig. 19.

Normally the inspiratcr replenishes the pres= sure and the float drops down to its normal position, shifting the weight E again to its inoperative position. If, however, the inspirator does not renew the pressure due to a serious rupture in the tubing or pipes or if the main water supply it for the inspirator should failfrom any cause when the inspirator is called into action by the effects of the predetermined air leak 245 acting independently of piping leaks the float continues to rise carrying with it the arm I91 until the pin Ap engages the pin A1 on the weighted element A, this element finally being thrown beyond its dead center position to the position shown in Fig. 20 and producing the actuation of thealarm valve controlled thereby. As the pressure is replenished the reverse operation takes place and the alarm valve is first shut off and then the inspirator valve is shut off as the float reaches the level a in the lower portion of the float chamber. This condition is indicated in Fig. 18.

The air in float chamber I85 is connected to the system of distributing pipes and to the supplemental tubing to maintain a definite pressure condition in the pipes and tubing. The connection from the float chamber to the distributing pipes is by way of conducting pipes 2I5 and 2I6, the latter entering the distributing pipes just above the back pressure valve 23. Check valve 2" prevents air pressure or water from passing from the distributing pipes back into pipe 2I6 and the control valve has operated.

The air connection from the float chamber I85 to the supplemental tubing includes the pipe 2| 8 leading to the air filter 220 which is connected by way of pipes HI and 222 and one way valve 223 with the interior of chamber 60 at the release mechanism.

The filter comprises an outer casing 224 (Fig. 16) having a connection with the pipe 2 I8 leading as just stated from the air chamber of the air injector or pressure producing device I84, the upper portion of the casing being closed by a cap 225 and the lower portion by means of a connecting plug 226. An intermediate cylindrical member or tube 228 within casing 224 is attached to the plug 226 and itself carries an additional closure cap 229, the intermediate member 228 being spaced from the wall of casing 224 and terminating short of the top of this wall to provide an upwardly extending cylindrical passage 230 which is in communication with the top of the downwardly extending passage 23I between the inner cylindrical wall of tubular member 228 and an inner cylindrical member or chamber 232. The latter is held at its top within a recess in an upper closure plug 233 carried by the cap 225 and is received within a similar seat in a lower closure plug 234 carried by the closure 229 so as to be held in position between these plugs. The inner chamber or member 232 communicates at its lower end through a series of openings 2335 with a chamber see in the closure 229 at the lower end of the space of passage 2% surrounding the same and connects at its upper end with the pipe 22i leading to the chamber se. The interior of the inner member or chamber 232 contains a porous body of moisture absorbing material such as calcium carbide, indicated at 238. This porous mass of material acts also as an air filter for straining dust or other impurities from the air.

It is held in position within the inner chamber 232 between the porous plugs 238.

As air is being introduced into the supplemental tubing through the air filter the heavy moisture is taken from the air due to the contact of the air with the walls 228 and 22d of the air passage in the filter body. This moisture runs back into the liquid in the float chamber. of the air that passes from said passage over the upper end of the cylindrical member 228- and down through passage 23! some moisture condenses out of this air and settles into the chamber 239 at the lower end of the filter. This moisture may be periodically removed by removing the plug 236. As the air passes upwardly throughthe filtering material 236 the remainder of the moisture is taken from the air so that only relatively dry air passes tothe sealed air chamber of the release.

In order to cause the periodic operation of the pressure renewing devices we have arranged a vent 240 of fixed capacity and communicating with the air pressure space at the top of float chamber of the air injector or inspirator I84 to permit the pressure therefrom to be gradually dissipated thus bringing about the periodic operation of the air injector. The vent disclosed may be as indicated at 245, Fig. 1 of the same type as vent I6 for equalizing the pressure between although it will be understood that other types may be provided'at 240 and that this vent or restricted outlet may be of variable capacity if desired.

In the operation of the above apparatus presaoaaoea release mechanism and the opening or the main v supply valve. If the temperature should rise very slowly so as not to operate the pressure responsive devices through the increase oipressure then on the attainment of a fixed relatively high temperature one or the fusible elements I 66 will be destroyed and the corresponding unit I 45 will be opened to the'outside pressure. The normal increased pressure within the unit and the additional pressure which has been added thereto through the increase in temperature is thus suddenly released and the release is operated through decrease of pressure in the tubing I44, thereby opening the main fluid control valve 41. As will be seen each double check flow unit provided for each tube prevents dissipation in the connection of each of said tubes to a common connection and dissipation of effects due both to operating increase and to decrease of pressure arising in any or all of the others.

The operation of the main fluid control valve 41 just described is brought about as follows (see Fi 12) Assuming that the manual pressure established by inspirator to be 1 1b., this pressure will be established in the distributing pipe system and in the chamber 60 and through the action previously described in the supplemental tubing I44 and the heat absorbing units I46. Should the fusible clement I66 be melted by heat or a break occur in the supplemental tubing I44, the pressure in the heat absorbing units I46 and the supplemental tubing I44 would escape to the atmosphere while the pressure in the chamber 60 ,would of course endeavor to escape, the only avenues being through the restricted vents 'I6I6 and I55, the pressure at I52 will be less than at I5I. Thus the greater pressure in I5I will lift mercury in the tube I53 until suflicient mercury-has risen in I52 to leave the lower end of I53 open, when of course the pressure in I5I will then become the same as in I52. This drop in pressure will be transmitted through I49 to the upper surface of diaphragm 66, allowing the diaphragm to travel upward in response to the greater pressure remaining in 60. This will operate lever 8| moving projection 83 out of contact with projecting flnger 84 (Fig. 9) thereby causing the release to operate and function fluid control valve 41;

When the apparatus is at rest the pressure in the inspirator I84 gradually decreases up to the point where the inspirator is brought into oper ation for bringing the pressure back to normal, a renewed supply of air being added directly to 1 the distributing pipes and through the filter 220 to the supplemental control tubing. If the pressure in the piping or tubing should fall sufliclently low then the siren 40 is actuated to indicate the abnormal pressure condition in the system. I

As will be seen, the system described permits balanced pressure other than atmosphere to be carried in chamber Gil-tubing I49I44 and heat devices I46, equalizes by vents I6-'I6' unbalancing pressure fluctuations resulting from normal temperature changes in the region of I46-preventing operation of diaphragm 66 and detent BI from normal temperature changes, and passes operating pressures due to fire in region of I48 through seal I54 and I4! to space Iii-thus moving diaphragm 65 outwardly and operating detent BI-without substantial loss of such pressure to chamber 50 or other tubing I44.

The system herein disclosed is of universal application in that it can be installed in heated or unheated buildings without danger of freezing any liquid in the distributing pipes or sup-i plemental tubing. The system can protect a large area since the pneumatic control impulses originating in the different fire zones are isolated and conveyed directly to the main pressure responsive device 65. The complete system is supervised for the detection of any breaks in the pipes or tubing, the system being operated through the supplemental tubing on a predetermined rate of rise of temperature or in any event on the attainment of a fixed relatively high temperature. The mounting of the control tubing as herein disclosed affords additional dependability to the apparatus by affording maximum protection andsecure supports for the tubing, which tubing however is exposed for inspection throughout most of its length.

It will be understood that pressure less than atmospheric may be employed instead of the inious other adaptations of the invention may be 'made without departing from the spirit of the present invention.

Having now described our invention, we claim:

1. In a fire controlling apparatus provided with a system oi. pipes containing air under pressure, a sealed float chamber provided with an air pressure space communicating with said pipes at the upper portion of said chamber and containing a fluid column whose level changes with change in the air pressure in said pipes, a float buoyed in fluid in said chamber, a plurality of pivotally mounted weighted operating elements adapted to be tilted, means controlled by said float for moving one of said elements beyond dead center to operating position on a certain rise of said float due to change of fluid level and for moving the other said element on a further similar rise of said float, means controlled by one of said operating elements for supplying air to said float chamber and pipes and means controlled by the other said operating element for operating an alarm.

2. In a fire extinguishing apparatus, a system of pipes containing air under pressure, a sealed float chamber provided with an air pressurespace communicating with said pipes and containing a fluid column whose level changes with changes in the air pressure in said pipes, a float buoyed in fluid in said chamber, pivotally mounted valve operating elements adapted to be moved past dead center and associated valves, means operatively connecting said operating elements with said float to be moved thereby when the level of fluid changes, said means causing one of said operating elements to be moved over pivotal center in advance of the other as said float rises with rise of fluid, an injector which simultaneously admits water and injects air into said chamher, said injector being operated by said element to be operated first and an alarm operated-by the other said operating element.

3. In a fire extinguishing apparatus, a system of pipes containing air under pressure, a float chamber, a float buoyed in liquid in said chamber and rising and falling with rise and fall of the the fluid, a plurality of pivoted weighted and sliii'table operating elements, a float operated actuator for said operating elements, said actuator and operating elements having coacting abutments for causing said elements to be successively shifted past dead center, an injector operated by one of said operating elements and an alarm operated by the other and means for connecting said actuator to said float.

4. In a fire extinguishing systemior a plu rality of fire zones, pressure producing devices in each fire zone, a main pressure'respon'sive device and means of communication extending from each of said pressure producingdevices to said pressure responsive device and each provided with a fiow control unit permitting substantially unrestricted air flow toward said pressure responsive device but preventing the return passage of low pressures from said pressure responsive de-v vice to any of said pressure producing devices, said flow control unit permitting the passage of relatively higher pressures past the same in either direction.

5. In a fire extinguishing system for a plurality of fire zones, pressure producing devices in each fire zone, a main pressure responsive device and means of communication. extending from each of saidpressure producing devices to said pressure responsive device, each provided with a flow control unit permitting substantially unrestricted air fiow toward said pressure responsive device but preventing the return passage of low pressures from said pressure responsive device to any of said pressure producing devices, said flow control flow toward said pressure responsive device but preventing the return passage of low pressures from said pressure responsive device to any of said pressure producing devices, said flow control unit permitting the passage of relatively higher pressures past the same in either direction, a casing enclosing said pressure responsive device I and communicating with the rearward operating face of said pressure responsive device and means for gradually equalizing the pressure between the interior of said casing and within said means of communication.

7. In a fire extinguishing system for a plurality of fire zones, pressure producing devices in each fire zone, a main pressure responsive device and means of communication extending from each of said pressure producing devices to said pressure responsive device, each provided with a' flow control unit permitting substantially unrestricted air fiow toward said pressure responsive device but preventing the return passageof low pressures from said pressure responsive device to any of said pressure producing devices,

said fiow control unit permitting the passage of relatively higher pressures -past the same in either direction, a casing enclosing said pressure responsive device and communicating with the rearward operating force of said pressure responsive device, means permitting the free passage-of air from said casing to the interior of said means of communication'and means for supplying air pressure to said casing.

8. In a fire controlling apparatus, pressure responsive'means responsive to either an increase or decrease of pressure for bringing said appament of a fixed relatively high temperature adja-- cent said unit.

9. In a fire controlling apparatus, pressure responsive means responsive to either an increase or decrease of pressure for bringing said apparatus into operation, a sealed heat responsive unit in a fire zone communicating with said pressure responsive means, means for unsealing said unit to cause change of pressure on said pressure responsivc'means, and means connected therewith for causing visual indication of the unsealing of the same on the attainment of a fixed relatively high temperature adjacent said unit, said last named means comprising a plunger normally positioned mainly within said unit and retained therein by heat responsive means which frees said plunger for movement to a position exposing the same without said unit on the attainment of said relatively high temperature.

10. In afire extingi'iishing system provided with a dstributing pipe, pneumatically actuated con= trol means for controlling the admission of fire extinguishing fluid to said pipe and including pneumatic impulse conducting tubing, means for supporting said tubing on said pipe, said supporting means comprising an outer element loosely embracing said pipe, and a channeled intermediate member received'within said outer element and coacting'w'ith said pipe for enclosing a sec== tion of said tubing.

11. In a fire extinguishing system provided with a distributing pipe, pneumatically actuated control means for controlling the admission of fire extinguishing fluid to said pipe and including pneumatic impulse conducting tubing, means for supporting said tubing on said pipe, said supporting means comprising an outerv element loosely embracing said pipe, and a channeled intermediate'member of general wedge shape-received within said outer element and coacting with said pipe for enclosing a section of said tubing, said intermediate member being formed with means for holding the same in its adjusted position with respect to said pipe.

12. In a fire extinguishing system provided with a distributing pipe, a sprinkler head, means for securing said sprinkler head to said pipe, pneumatically actuated control means for controlling the admission of fire extinguishing fiuid to said pipe and including pneumatic impulse conducting tubing, and means for supporting said tubingon said pipe, said supporting means comprising a shield formed with a semi-circular body part extending partially around said sprinkler head and having'an outer wall spaced from said head to provide a longitudinal passage ex; tending around said sprinkler head.

, 13. In a fire extinguishing system provided with a distributing pipe, a sprinkler head, means for securing said sprinkler head to said pipe, pneumatically actuated control means for controlling the admission of fire extinguishing fluid to said pipe and including pneumatic impulse conducting tubing, means for supporm vgsaidtubing on said pipe, said supporting means compris-.

ing a shield formed with a semi-circular body.

part extending partially around said sprinkler head and having an outer wall spaced from said head to provide a longitudinal passage extending around said sprinkler head and means for securing said shield beneath said sprinkler head.

14. In a flre extinguishing system provided with a set of fluid conducting pip means for maintaining pressure other than atmospheric pressure in said pipes and comprising an air pressure responsive mechanism for producing an air flow, and arbitrarilysetmeans for gradually venting the air in an air pressure c saidpressure maintaining means connected to said pipes up to the point at which said air pressure responsive mechanism will act tomaintain the air pressure. v 15. In a flre extinguishing system provided with a set of fluid conducting pipes, means for maintaining pressure other than atmospheric pressure in said pipes and comprising an air pressure responsive mechanism for producing an air flow to maintain said pressure other than atmospheric, and a fixed leak for the said air under pressure in said conducting pipes operating on said pressure responsive means to cause periodical operation of the pressure maintaining means.

16. In aflre extinguishing system provided with a set of fluid conducting pipes, pneumatically actuated control means for controlling the admission of said fire extinguishing fluid to said pipes,

- a pneumatic impulse conducting tubing to said control means, air pressure producing means connected to said tubing, air. pressure responsive mechanism controlling the action of the latter means and adapted to cause the same to operate on diminution of said air pressure and a fl xed air. leak for periodically bringing the latter means into operation.

' i7. In a flre extinguishing system provided with a set of fluid conducting pipes, pneumatically actuated controlled means controlling the admission of flre extinguishing fluid to said pipes and including pneumatic impulse conducting tubing having an air chamber connected thereto, an iniector operating when the water in the chamber reaches a predetermined level simultaneously admitting water and injecting air into said chamber, said chamber having means for raising the water level therein upon decrease of the air pressure and for lowering the water level upon increase of the air pressure, a float in said chamber controlling the action of said injector by the said rise and fall of the water level in said chamber, and a flxed'air leak acting as a constant leak for the air supplied by the injector to the tubing for periodically bringing the injector into action through the operation of the float.

18. In a fire extinguishing system, a pneumatic controlling device comprising a double acting diaphragm and means for operating said device on movement of the diaphragm in either direction, a system of tubing communicating with one side of said diaphragm, a closed casing enclosing said diaphragm and communicating with the opposite side of said diaphragm, means for introducing compressed air into said enclosing casing and a valve opening into said casing and into said tubing constructed and arranged for permitting passage of air'from said tubing past said valve to the diaphragm but preventingthe passage of air from said diaphragm past the valve into said ber oi tubing under normal conditions while permitting passage under abnormal conditions.

19. In a flre extinguishing system, the combination of distributing pipes, a main'valve normally closed and adapted to admit fluid to the distributing pipes, a releasable actuating weight and means actuated thereby for freeing said main valve, a pivoted latch carried by said weight. a releasing member for releasing the same, means responsive to change of pressure generated by heat in the fire zone for operating said releasing member and independent means for freeingthe latch to permit the weight to fall while the pressure controlled releasing device is inoperative position.

20. In a fire extinguishing'apparatus provided with a distributing piping for the flre extinguishing fluid, a weight, a fluid supply means therefor and a controllever operated by saidweight in falling and a guide for said weight pivotally connected at its lower end with said control lever and provided with a guide at its upper end.

21. In a flreextinguishing apparatus, the combination of a main valve, releasing means f r the 22. In a release mechanism, a diaphragm, a

housing therefor provided with a diaphragm chamber having an outwardly bowed wall adjacent the opposite faces of said diaphragm limiting deflection of the diaphragm in both directions, said diaphragm chamber communicating freely with the outside air on one side of said diaphragm and through an impedance with the other side of said diaphragm, means for convey ing pneumatic pressure to the last named side of said diaphragm, a main release member and means for releasing said release member on movement of said diaphragm in either direction.

'23. In a release mechanism, a diaphragm, a housing therefor provided with a diaphragm chamber having an outwardly bowed wall adjacent the opposite faces of said diaphragm limiting deflection of the diaphragm in both directions, said diaphragm chamber communicating with a pressure conveying conduit on one side of said di phragm, a main release member and means for releasing said release member on movement of said diaphragm in either direction.

24. In a release mechanism, a diaphragm, a housing therefor provided with a diaphragm chamber having an outwardly bowed wall adjacent the opposite faces of said diaphragm limiting deflection of the diaphragm in both directions, said diaphragm chamber communicating with pressure conveying means on one side of said diaphragm, a main release member, means for releasing said main release member on movement of said diaphragm in either direction and means for normally retaining said diaphragm in a central neutral position.

25. In a release mechanism, a main release responsive means responsive to a change of pressure for bringing said apparatus into operation,

a sealed heat responsive 'unit in a fire zone adapted to cause increase of pressure when heated and communicating with said pressure responsive means, means for unsealing said unit to cause diminution of pressure and means for indicating the unsealed condition of said unit on the attain- .ment of a relatively fhigh'temperature adjacent said unit.

28. In a fire extinguishing system, distributing pipes, a source of fire extinguishing fluid supply communicating with said pipes, means for controlling the passage of fluid from said source to said pipes, a fluid pressure actuated motor and alarm operated thereby, an auxiliary valve for closing off the supply of fluid from said pipes and controlling means and means for supplying fluid pressure to said motor from a source aficrding pressure when the auxiliary valve has been operated to closed position independent of that remaining' in the pipes after the auxiliary valve is closed for giving a continuing alarm of full force by the action of the fluid motor so long as said auxiliary valve remains in closed position, and another-alarm operable independent of the fluid pressure also put into action by operating the auxiliary valve to closed position. v

29. Ina fire controlling apparatus, distributing pipes for a fire extinguishing medium, means normally inactive adapted to supply said medium to said pipes, a latch normally holding the same out of action, a releasable weight adapted to engage the latch of said supply means by hammer action, a release lever for said weight, pressure operated detent mechanism for said release leveroperated by pressure generated in the fire zone and contained in a sealed casing having a sealing opening through which said release lever extends, an exterior housing for said weight provided with a guide therefor and a releasing detent carried by said weight and engaged with the projecting end of the release lever projecting from said casing.

30. In a fire extinguishing system having distributing pipes for a fire extinguishing fluid, the combination of means for admitting said fluid to the piping, release devices pressure controlled and enclosed in a sealed chamber, a weight, an exterior housing therefor, a releasing member for said weight extending through a sealed opening in the chamber and a resetting device mounted in a sealed opening in. said chamber and engaging said release devices for resetting the same.

31. In a fire extinguishing apparatus having .a pressure controlled release the main op r n and releasing elements of Y which are enclosed within a sealed chamber maintained at a pressure of the pressure controlled release and an exterior resetting device extending through a' sealed opening in said chamber and adapted to engage an operating element for the purpose of resetting the same.

32. In a fire extinguishing apparatus having a pressure controlled release the main operating elements of which are enclosed within a sealed chamber, an exterior resetting device extending through a sealed opening in said chamber and adapted to engage an operating element for the purpose of resetting the same, means for admittingflre extinguishing fluid to the piping, an operating weight therefor housed in an outside chamber and releasing catch for the weight controlled by an operating element of the release extending through a sealed opening in said chamber.

33. In a fire controlling apparatus distributing pipes for the fire extinguishing medium, a weight operated control for the supply therefor, a weight releasing lever mounted in a sealed casing and subject to the control of release detents in said casing pressure controlled from the fire area, and an exterior housing containing said weight, the said weight releasing lever extending through a sealing opening in the sealed casing for engagement with said weight. I 34. In a fire extinguishing apparatus having a distributing 'piping, fluid supply means adapted to supply fire extinguishing fluid to said pipe, a catch normally holding said fluid supply means out of action, a release lever and pressure operated detent mechanism therefor both contained in a sealed casing and means controlling the catch of said fluid supply means mounted in a housing exterior to the sealed casing and in operative control engagement with the release lever by an extension of said. release lever through a sealing opening in the sealed casing.

35. In a fire extinguishing system provided with a distributing pipe, a source of fire extinguishing fluid supply, gate valve controlling the passage of said fluid to the distributing pipes, a fluid pressure actuated alarm controlled by said gate valve and operated by pressure derived from the source of fluid supply admitted to said alarm on closing the gate valve and an auxiliary source of fluid supply supplying fluid through the controlling action of the gate valve independently of the supply derived from the extinguishing fluid.

36. In a fire extinguishing system, distributing pipes, a source of fire extinguishing fluid supply communicating with said pipes, a gate valve controlling the passage of said fluid to the pipes, a fluid pressure actuated alarm, means for admitting fluid from the source of supply to said alarm and affording fluid pressure for actuating the alarm in case of failure of the alarm to operate when the gate valve is closed and an auxiliary source of fluid supply connected to the gate valve.

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