US1264393A - Chemical fire-extinguishing apparatus. - Google Patents

Description

J. R. HAMILTON.

CHEMICAL FIRE EXTINGWSHING APPARATUS.

APPLICATION HLED AUGMI, 1915- Patented Apr. 30, 1918.

3 SHEETSSHEET I J. R. HAMILTON. CHEMICAL FIRE ixrmsmsnmc APPARATUS.

APPLICATION HLED AUG.4. 1915- Patented Apr. 30, 1918.

3 SHEETS-SHEET 3.

ATTORNEY UNITED STATES PATENT OFFICE.

YORK, ABSIGNOR '10 SYPHO-CHEMICAL DN-ON-HUDSON, NEW YORK, A CORPO- CHEMIGAL FIRE-EXTINGUISHING APPARATUS.

To all whom it may concern.-

Bc'it' known that I, JOHN R. HAMILTON, of Yonkers, county of Westchester, State of; New York, have made certain new and useful Inventions Relating to Chemical Fire-Extinguishing Apparatus, of which the followng is a specification, taken in connection with the accompanying drawin$, which form part of the same.

his invention relates especially to fire extinguishing apparatus'in which the distributing system may comprise automatic or other distributing devices and in which a chemical rmixing tank may be used to supply supplemental extinguishing liquid to t e system. The mixing devices ating with the tank may comprise a primary or tarting chemical chamber having a dischal'ge connection through which the chemi: cal tends to discharge, but which may be provided with a trapped or other retainin portion in which a mercury or other liquid may be normally held on the emergency opthus releasing the seal restraining device until it is withdrawn oration of'the system, primary charge of acid or other chemical which is discharged into the tank to generate the high emergency pressure therein. Supplemental pressure maintaining devices may be used to preferably maintain the einergency discharge pressure substantially constant and these devices may comprise a supplemental chemical feeding chamber and connected pressure governing chamber above between which a charge of mercury may be transferred by the tank pressure to act as an automatic plunger and feed additional acid into the tank whenever the tank pressure decreases below the predetermined amount.

In thenccom anying drawings showing in a somewhat diagrammatic Way illustrative embodiments of this invention- Figure 1 is a vertical section showing one form of apparatus.

Fig. 2 shows a modified construction.

Fig. 3 shows another embodiment.

Fig. 4 is a detail section thereof showing the parts in another position; and

Fig. 5 shows still another embodiment of the invention.

In the illustrative embodiment of the invention shown in Fig. 1 the distributing system, which may be of any desired form Specification of Letters Patent.

Application filed August 4,

Patented Apr. so, 1918. 1915, Serial No. 48,586.

and arrangement, may comprise a supply pipe, such as 3, with which are connected -one or more distributin lines 6 having any "suitable distributing evices, such as the automatic sprinkler heads 7, arran ed at suitable oints throughout the building. The distributing s stem is preferably normally charged wit suitable extinguishing liquid, such, for example, as a suitable nonfreezing solution which is normally kept at sufficient pressure to dischar e from the distributing devices by a suitable priming actuating tank, such as 32, extending upward, so that the non-freezing or other extin ish-- ing liquid 33 h'as'sufiicient head to disc 'ar e from the operating emergency devices. 1':

case non-freezing solution is used in the sgl tem a check valve, such as 4, is prefer arranged at the lower portion of the supply pipe which may be connected with a supplemental supply of extinguishin liquid which may, if desired, comprise a c emical pressure tank such as the chemical mixing tank 1 into which extends the suppl connection 2 communicating with the supp y pipe 3. If desired, a suitable venting device such as the automatically closing ball check 5, may be arranged he ow the check valve 4 in which case it is sometimes desirable to have an equalizing opening, vent 60 between the supply connection and the upper part of the mixing tank which may, if desired, be filled with an extinguish? ing liquid having in solution a pressure generating chemical, such,

the ordinary carbonate extinguishing-liq? uid 8.

may be arranged. incoiiperation with the mixing tank and may comprise a starting device adapted under fire emergency conditions to discharge intothe tank a millcient quantity of chemical to generate in connection with the chemical charge already such as the pin hole 1 Any suitable chemic l mixmg g;

for instance an through the m the upper part a removable cover 15, ii. desired. This starting charge normally tends to discharge into the mixing tank through a discharge connection which may comprise the trap 27 and the discharge pipe 30 extending through the open throat 31 of the casing, a suitable equaizing opening 19 being arranged in the top of the chamber to iacilitate this discharge. A suitable restraining device may coiiperate with the discharge connection so as to normally restrain the discharge of the starting chemical therethrough and for this purpose it is desirable to employ a liquid seal or plug 28 of such character and composition as not to be undesirablyacted on by the starting chemical and, to effectively restrain its discharge, mercury being a convenient and effective liquid seal for this purpose when the starting charge is of sulfuric acid, for instance.

This restrainin mercury seal or plu may be normally be d in the position in'icated in Fig.1 bythe fluid pressure in the system as by. allpwingthis premure to be exerted actuating pressure pipe 9 on the actuatin chamber 10 which contains a charge 11 o mercury so that under these conditions the normal pressure in the sys temforces part of this mercury up through the actuatingv transfer pipe 13, the lower part 12 of which extends adjacent the bottom of the chamber so asto maintain. an efl'ective restraining liquid seal or plug 28 in the. discharge connection which is forced upward in. the trap sufliciently to sustain the pressure caused by the starting charge 18 above. Under emergency conditions when one or more of the distributing devices opens and liquid from the system is discharged therethrough the pressure exerted in the actuating chamber is correspondingly decreased and the mercury from the transfer pipe and trap retintcrs the actuating chamber so as to allow a free passage through the tra. ped discharge connection through. which t c said or other chemical charge 18 uickly flows into the mixing tank, a vent ng passage 26 being arranged of this discharge connection m case it is desired to prevent" siphon action, although otherwise this passage is unnecessary. This rapidly generates the ,of thegas in'the upper part emergency chemical gas pressure within the tankand forces the. extinguishing liquid up through the supply connection so as to close the venting device li and open the check valve; 4 so as: to supply liquid to the distributin system for high pressure dis charge rom theoperating distributing devices. Under these conditions the pressure of the mixing tank and connected casing equals or exceeds the pressure .in'tbellsupply pi e 3 so that the mercury remains within t e actuating chamber and has no tendshcy whatever to .25 which may be normally close sure falls so that through suitable co interfere with the flow of any remaining part of the starting charge 18 into t e tank. Any suitable means may be emp oyed to maintain the desired high emergency pressure in the mixing tank while the char e of oxtingu ishing liquid is being discharged rom the system and preferably suitable chemical mixing devices are arranged in connection with the tank to maintain this emergency discharge pressure substantially constant throughout at least the greater part of the discharge from the tank. Fig. 1 illustrates one of a number of suitable supplemental chemical mixing devices which may be used for this purpose in connection with the starting devices shown in this form of the invention and as therein indicated a sup"3 plemcntal chemical or acid holder 21 may arranged or formed as one chamber of the multiple receiver 16 within the casing14 and preferably provided with the upper vent or opening 20 sov as to normally contain a suitable supplemental charge 22 of pressure generating chemical or acid adapted to react with the chemical 8 in the mixing tank below. Under emergency conditions this supplemental chemical charge is adapted to be transferred to the supplemental chemical or acid feeding chamber 23 as by passing through the holder discharge passage or pipe by any convenient device, such for instance as the seal or plug 24 of suitable liquid, such for example, as mercury, which may partly fill the feeding chamber under normal conditions. Under emergency conditions when the high emergency pressure is chemically generated in the tank this mercury seal 24 may be largely or partly forced out of the feeding chamber as througha transfer pipe so that the fiower end of the holderdis charge pipe 25 is thus uncovered and the supplemental charge of chemical or acid '22 thereupon bodily descends into the supchamber 23 which is 0f 11 plernental feeding such size as to be thus substantially filled with this supplemental chemical charge which is subsequently gradually fed into the mixing t'ank whenever the emergencg preg- P m ing governing means or devices the, e ergency discharge pressure may be maintained substantially constant in the mixing tank. and connected distributing system. These governing devices may "comprise a pressure governing chamberfsuch as 36, arranged at such height above the feeding chamber as to produce a gravity pressure head of the mercury or other liquid seal substantially equal to the cmergemy discharge pressureinthe tank This pressure govcrniugchamber is preferably made of such capacity so thatgctbor with the governing transfer i aas.

conne ting it with tbecontrol chambemthe'w mercurycharge in these parts substantially fills this governing chamber when the mercury is forced up into it to such extent as to first uncover the lower end of the holder discharge pipe. Any suitable over-pressure control devices may be arranged in connection with the pressure overning chamber so as preferably to consi erably increase the pressure orliquid resistance exerted against any further passage of the mercury from the feeding chamber into the governing chamber and this may be conveniently effected by having a relatively small area over-pressure reservoir pi e 38 connected to the pressuregoverning e amber so that the entrance of any further mercury into this governing chamber forces mercury. into this over-pressure reservoir pipe an causes such a rapid rise therein as to produce a correspondingly rapid increase in the gravity head thus exerted and, correspondingly minimize the danger of: the mercuryseal pressure device being rendered ineffective. Under emergency conditions after the mercury has been forced up to substantially fill the pressuregoverniiig chamber 36 and after the acid 22 has descended into the supplemental feeding chamber to substantially fill the same above i the thin layer of mercury remaining in the bottom of this chamber any decrease in the gas pressure within the mixing tank causes a corresponding descent of the mercury fromv the governing chamber into the" supplemental feeding chamber 24 so as to force a corresponding amount of the acid over the discharge "Ii 34 of this feeding chamber down into t e acid discharge pipe 30 c0mmunicating "with the mixing tank. This quickly generates additional pressure in the tank and tends to force the mercury back from the feedin chamber into the pressure governing chem )er. The chemical or acid is thus gradually fed= from the feeding chamber in'zi series-of relatively small increments whenever the emergency pressure begins to fall in the tank and by making the supplemental feedin chamber and thepressure overnihgzcham lier of such proportions as to e relatively fiat or shallow the emerency pressure'within the mixing tank'may is regulated quite closely. By arranging the pressure governing chamberseVeraI feet above the supplemental feeding chamber so as to secure a'mercury pressure head of 50 to 100 pounds or so per square inch which is sustained under emergency conditions by the gas pressure within the mixing tank any de crease in this gas pressure of a few pounds such as would allow the level of the mercury in the pressure governing chamber to fall from the top of that chamber to about the point indicated bythe dotted line 37 would cause a'corresponding volume of mercury to flow from the governing chamber into the feeding eh'amberwhere it would act as a feeding plunger or piston to feed a correspending volume of acid or pressure generating chemical into the mixing tank. Under some conditions it is desirable to limit the rate at which acid is discharged from the supplemental feeding chamber so as to prevent an undesirable sudden rise of pressure in the tank and for this purpose the effective area of the governing transfer pipe 35 may be ropcrly proportioned or controlled prefera 1y by interposing therein a throttling check valve, such as 75, which is adapted to be held down on its seat 76 when the mercury descends during one of these feeding impulses, so that all the mercury is then forced to pass through the restricted throttling passage 79 in this valve. The valve is, however, allowed to rise against the action of the light spring 78 shown above it so that the valve engages suitable stops or guides 77 so as to allow the free upward passage of the mercury during the start of the emergency operation of the device, for instance, the size 0 these parts being somewhat exaggerated in Fig. 1 for greater cleerness.

A" somewhat similar starting device is shown in Fig. 2 as comprising the starting chamber 17 containing the charge 18 of starting chemical or acid charge into the mixin tank 1 through the discharge connection 6% preferably comprise ing the trap 68. A restraining device automatically actuated on the emergency condition of the distributingsystem is arranged to cooperate with this discharge connection and may comprise the liquid or mercury seal 28 normally forced up the transfer pipe 13 from the actuatingchamber 10 by the pressure exerted on the upper surface of the merwhich tends to discury ll in this actuating chamber by a suitable actuating connection or pipe BO which may normally communicate with the priming actuating tank 32 or other upper part of the distributing system so as to receive liquid 33 therefrom. As indicated in Fig. 2 this charge of extinguishing liquid'in the distributing system may in some cases be the same as the chemical charge 8 in the mixin tank and thisarrangement may be efiected by keeping normally a suflicient air p ssure in the mixing tank 1 so as to force "extinguishing liquid 11 to the top of the ystem Where a sight g ass 81 indicates its normal position. Under fire emergency conditions when one of the distributin devices comes into operation the liquid is discharged from the system and suflicient suction or pressure reduction is thus developed in the substantially closed upper part of the distributing system with which the suction ac? hinting pipe 80 communicates, so that a sue t-ion impulse of a numbcrof pounds or so is thus exerted on the actuating chamber 10 and the mercury seal 28 is thus quickly withdrawn from the trap 68 and the starting charge 18 thus quickly flows over the lip 69 and through the discharge pipe 67 without the necessary action of any solid movin parts. oped in the tank causes a flow of liquid through. the supply ipe 3, the inertia and friction effects of the hilllld in these pipes being sufiicient to make t e air pressure in the tank exceed for a time at least after the distributing devices begin to operate, the pressure initially caused by the actuating pipe 80 in the actuating chamber 10 so that b making the. area of the discharge pipe 6 ample the certain discharge of all of the starting charge 18 may be effected. By arranging the lower end 81 of the suction actuating pipe 80 in such position that it dips into the mercury 11 in the tank before the relatively large area transfer pipe 13 is free from mercury, an effective mercury seal is always maintained between the gas s ace of the mixing tank and the upper part 0 the system.

By thus quickly discharging a predetermined amount of acid or pressure generating chemical 18 into the mixing tankthe desired emergency pressure can be developed therein and this pressure can thereafter be maintained substantially constant by any suitable pressure maintaining devices of a chemical mixing character, for instance, the supplemental chemical or acid chamber 70 may for this purpose be arranged within the easing 14. and may be partly filled with a supplemcn al charge 71 of acid or other Pressure" producing hemi al which is radually dis charged through a siphon disc arge pipe 72,

the lower end 7 3 of which is adjacent the bottom of the supplemental chamber, whenever the emergency gas pressure in the tank falls. When the system comes into emergen operation the air nd gas in the tank pass into this discharge spout 72 so as to develop the same-emergent: ressure within this supplemental cham er and then whenthe pressure in the tank falls a few pounds this pres sure within the chamber is suflicient to force out an increment of the acid or chemical charge which passes out of the spout72 into the discharge pipe 74 communicating with the tank. Thus additional gas pressure is chemically created and a substantially constant emergency pressure can be maintained throughout a large part at least of the discharge of the extinguishing liquid from the tank.

Another suitable arrangement is'indicated in Fig. 3 as preferably though not necessarily comprising a wet pipe distributing system which may be charged with non-freezing exting-uishiug liquid 33 separated by the check valve 4 from the supply connection 53 communicatingwith the bottom of the chemical mixing tank 39. This tank may contain a charge 40 of carbonate extinguishing liquid or other suitable pressure producing chemi- The chemical pressure then deve the mercury cal and the starting device may e06 crate therewith so as to produce the qgasired c emical pressure under emergenc, conditions. This starting device'may comprise the primary chemical or acid chamber 34 containing a charge 35 of sulfuric acid or other suitable chemical which tends to flow through the discharge pipe 138 into the mixing tank. This discharge pipe or connection may comprise the trap 136 in which may be located a restrainin device such as the mercury seal 42 normal y forced u through the tra fer pipe 13, the lower en 12 ofwhich dips to charge 11 in the actuating chamber 10. T e actuating ressure pi e 9 may connect with any suitable part 0 the dis tributing system so as to transmit the pressure of the air or liquid therein to the tank and force the mercury seal into its restraining position indicated in Fig. 3. Under emergency conditions, however, this ressur on the actuating tank is decreased su ciently so that the mercury seal is withdrawn from the discharge pipe and the acid charge 35 quickly flows up overthe siphonpbrtion 137 of the pipe into the mixing tank, the equalizing pipe 4l allowing this flow to take place without lnterruption.

Any suitable pressure maintaining devicemay be used in connection with this form of the apparatus so as to supply additional amounts of acid or pressure producing chemical to the tank whenever the gas ressure .jalls therein nd as indicated the c emical tainer 52 pivoted, for instance, about they pivots 46 in the casing 43 connected to the tank through the throat 51. The lower part of this casing 43 is adapted to contain mercury or other sustaining liquid 49 in which the container is more or loss floating under emergency conditions and the casing is connected by the governing transfer pipe 50 with the governing pressure chamber 86 so that on decrease of the gas pressure in the tank more mercury flows into the chamber so as to lift and tilt the acid container and discharge part of its contents through the spout 47 into the tank as indicated in Fig. 4. If desired the pressure governing chamber 36 may be provided with an ever-pressure reservoir pipe 38 so as to take care of excess pressures. If desired also part of the mercury charge for the casing 43 may be contained in a weighting compartment 44 on the container so that the parts, under normalinactive condition of the system, are in the position indicated in Fig. 3.- When, however, the system comes into emergency operation the increase of gas pressure in the 3 and the distributing line 6 having tank drives the mercury up into the pressure governing chamber 36 so that the container tilts downward away from its pivot and a large part at least of the supplemental charge 45 of mercur is discharged from this compartment into the casing 43 so as to increase the amount of mercury therein.

, Another arrangement is shown in Fig. 5 as preferably comprising a wet pipe distributing system comprising the supply pipe any suitable distributing devices or sprinkler heads 7 The check valvc l may be arranged to maintain the desired non-freezing or other extinguishing liquid in the system under'normal conditions and if desired an automatically closing ball check venting device 5 may-be arranged below the valve between it and the supply connection 2 extending into the carbonate or other chemical charge 8 in the mixing tank 1. A pin-hole equalizing aperture 60 is preferably ar ranged in this connection as in the case of the Fig. 1 arrangement. The acid or coo'peratin pressure generating chemical 129 maylie contained in a casing or chamber Hi7 mounted on the tank and provided with a harge aperture 131 nor'mally held closed-by the control valve 130. This valve may be mountedon the stem 128 secured by the nutsor washers 124 to the flexible metalor other control diaphragm 125 mounted within the cover 126 of the casing. A

J sprin 123 is arranged above this diaphragm and t e adjusting nut 122 may beadjusted above'this spring so as to regulate the pres sure within the chamber which will tend to keep the diaphragm closed. Under normal inoperative conditions where the tank is under atmosphericor other pressure less than the usual high emergency discharge pres sure this diaphragm valve tends to open and a suitable restraining device is used in connection therewith to normally keep it closed until the s stem comes into emergenc operation. mercury float restraining evice f may be used for this purpose and may comprise the float 116 of any suitable material arranged within the float chamber 114 and pivoted by the pin 117 to the restraining levcr 118. The other end of this lever is pivotedby the pin 120 to the bracket 121 on the casing cover and under normal conditions the lever is held up against the underside of the ,head- 119 on the valve stem by the mercury 1 15 around the float 116. This mercury is under normal conditions forced up from the actuating chamber 10 by the action of the actuating pressure transfer pipe 9 which transmits the liquid or other pressure from the system so that it acts on top of the mercury 11 in this chamber and forces it into the end 12 of the transfer ipe 13 so as to raise it'into the float chain er to about the extent indicated. This powerfsm straining closing action is exerted on the valve stem and valve which is thus kept tightly closed under normal conditions. When, however, one of the distributing devices opens and allows the pressurein the system to fall the mercury is no longer held up in the float chamber and its fall allows the float and'connected control or restraining lever 118 to descend so that the control spring 123 quickly opens the valve 130 and allows SllfilClBIlb acid to run into the tank to quicklydevelo the desired emergency pressure therein. his pressure is transmitted through the equalizing pipe 141 to the casing below the diaphragm so that as soon as the predetermined emergency discharge pressure is reached the diaphragm is pushed upward against its spring and tightly closes the control valve 130. Any decrease in this amount of pressure above the atmospheric pressure which is actin on the upper side of the diaphragm quic 1y causes a corresponding supplemental flow of acid so that as long as any of the acid char e remains the tank pressure is kept at su stantially the predetermined emergency pressure. Under these emergenc conditions also the emergency ressure rom the tank and equalizing pipe 141 is transmitted through the pipe 142 to the to of the closed float chamber 114 so that t e mercury tends to descend into the actuating tank 10 and remain there so as to have no further action on the float 116.

. It'is of course desirable to form the acid containers and cooperatindg trapped portions of the communicating ischarge passages with which the mercury and acid coilperate of some suitable material which is not undesirably acted upon by these substances. If desired, glass or chemical earthenware may be used for these parts of the apparatus and also preferably for the cooperating actuating overnin chambers, although acid does not ave such extended or continued contact therewith. In some instances, however, a suitable protective coating, such as bakelite, or other resistant coating preferably of a somewhat elastic-resilient character may as indicated in Fig. 2 be applied to cast iron or other suitable metal chambers and connected pipes having proper form so that the acid and mercur are prevented from having undesirable dlrect contact with the metal.

This invention has been described in 0on nection with a number of illustrative embodiments, forms, arrangements, materials,

PIOPOI'LIOIIS, sizes and arts of the apparatus,

to the details of whlch disclosure the invention is not of course to be limited, since what is claimed as new and what is desired 4 i to be secured b Letters Patent is set forth in the appends claims:

1. In automatic fire extinguishing appa= ributing devices,

ratus, a distributing system comprising disa supplemental supply of extinguishing liquid connectcd to said system and comprising a chemical mixing tank charged with carbonate liquid and cooperating mixing devices including a startln device comprising a starting charge of am and communicatlng with said tank, a restraining device coiiperating with saidstartingdevlce, [an actuating pressure pipe connecting said rcstrainin device and said distributmg system to e ect the discharge of said acid into said tankto generate emerfire emergency gei c'y pressure in 'saidtftanlc comprising a cup viemehtal cid 'T edin chamber having a ch massage oonnnunicating with Suid1iifihk,"i a" governing transfer ipe con- 045 sai r-ceding c l p napressuregevemm chamber conchamber, ali over pressure reservoir pipe connected to said governing transfer pipe and extending above said pressure governing chamber, a charge of mercury n'ormally located in said feedingchamber, a supplemental charge of acid in said'feediiagchamber in contact with said mercury, sai pressure governing chamber bein located at a height above said feeding chal ber producing agravity head corresponding with the emergency pressure in said tank to effect the forcing of said mcron into said pressure governing chamber nu. erlemergency conditions to feed the acid ffiOfiiBffi-id feeding chamber into said tank by the iaegersee n of the mercury from said pressure 9YQiug chamber Whenever the taifiiipfssure falls below the normal emergeneypressui'e. a

-2'. ,In aut matic fi e, extinguishi ap amt fili fine eye am empr sm extinguishing liquid connected to said sys tem d "ihiiiismg a chemical mixing tank a ith carbonate liquid and cooperuting min ngdevices' including a starting device Ito;eficctithe'discharge of said acid into said tank to generate the. emergency pressure therein under fire emergency conditions, and means to maintain the emergency pressure in 'sa'id tank com rising a supplemental acid feeding chamber aving adischa'rge passage communicating with'said tank, a governm traus-fer papa connected to the lower ingfchamber, a pressure governing chamber connected tosaid governingtransfer pipe and located above said feeding chamber, an over-pressure reservoir pipe; connected. Lto said governing transfer pipe and extending above said pressure gov- I ernrng chamber, a charge of mercury normlly located in saidteeding chamben'a-sup- 'plcment al' charge of acidin said feeding transfer iipeand said feeding asu'pp emental supply of.

I chamber in contact with said mercury, said pressure governin chamber being Located at a height above sai fceding'chambcr producing a gravityhcad corresponding with the emergency pressure in said tank to effect the forcing of said mercury into saidpressurc governing chamber under emergenc conditions to feed the acid from said fieding chamber, into said tank byvthe plunger action of the mercury from said pressure gov er in chamber whenever the tankpressure fa ls clow the normal emergency pressure.

3. In automatic fire extinguishing ratus, tributing devices, a supplemental supply of extinguishing liquid cohnected to said system and comprising a chemical mix tank charged with carbonate liquid and coiiper ating mixing devices including a starting device to c'ffectthe'dischargc of saidacid into said tanigtogcnerateiemergency pressiirc therein under fire emergency conditions,

and means to maintain the emergency pres-- sure in said tank comprising a suppiemental acid feeding chamber having a discharge passage communicating with said tank, a governing transfer pipe connected to the lower part of said feeding chamber, a pres sure governing chamber connected to said governing transfer pipe and located above chamber, a charge of mercury normally located in said feeding chamber, a supplemental charge of acid in said feed ing chamber in contact with saidmercury, said pressure governing chamber being located at a height above said feeding chamber produciuga gravity head corresponding with the emergency pressurei'n saidtanl; to effect the forcing of "said mercuryinto said pressure governmg chamber under emergency conditions to feed the acid from said feeding chamber intc said tank by uie'plua ger'action of the mercury from said pressure governing chamber Wheneverthe tank pres sure falls below the normal emergency sure. 1 y i 4.'In fire extinguishing apparatus, supplemental supply of extinguishing iiquld adapted to be connected to the distributing system and comprising a chemical mixing ip?- a distributing system comprising istank charged with chemical and means to a depending diswhich said discharge pipe pro .aeaiiig and extending above said pressure governing chamber, a charge of mercury normally located in said feedin chamberand closing the depending end of said discharge pipe, a supplemental charge of acid in contact with said mercury in said feeding chamber, said pressure governing chamber being of such size as to be substantially filled with the mercury forced thercinto when the emergency ressure is first developed and being located at a height above said feeding chamber producing a gravity head correspondin with the emergency pressure in said tan to effect the feeding of said supplemental acid charge from said feeding chamber into said tank by the plunger action of the mercury from said pressure governing chamber when the'tank pressure falls belowthe normal emergency pressure.

5. In fire extinguishing apparatus, a sup plemental supply of extinguishing liquid adapted to be connected to the distributing system and comprising a chemical mixing tank charged with chemical and means to cause an emergency pressure in said tank, and means to maintain the emergency pressure in said tank com rising a supplemental acid feeding chamber aving a discharge passage communicating with said tank, a governing transfer pipe connected to the lower part of said feeding chamber, a pressure governin chamber connected to said overning trans er pipe and located above said feeding chamber, an over-pressure reservoir pipe connected to said governing transfer pipe and extending above said pressure governing chamber, a charge of mercury normally located in said feeding chamber, a supple mental charge of acid in contact with said mercury in said feeding chamber, said pressure governing chamber being of such size as to be substantially filled with the mercury forced thercinlo when the cn'iergency pres sure is first developed and being located at a height above said feeding chamber producing a gravity head corresponding with the emergency pressure in said tank to effect the feeding of said supplemental acid charge from said feeding chamber into said tank by the plunger action of the mercury from said pressure governin chamber when the tank pressure falls below the normal emergency pressure.

6.In'fire extinguishing apparatus, a supplemental supply of extinguishing liquid adapted to be connected to the distributing system and comprising a chemical mixing tank charged with chemical and means to cause an emergency pressure in said tank, and means to maintain the emergency pressure in said tank comprising a supplemental acid feeding chamber "having a discharge passage communicating with said tank, a

governing transfer pilpe connected to the lower part of saidfee mg chamber, apressure governing chamber connected to said governing transfer ipe and located above said feeding cham er, an over-pressure reservoir pipe connected to said governing transfer pipe and extending above said pressure governing chamber, a charge of mercury normally located in said feeding chamber, a supplemental charge of acid in contact with said mercury in said feeding chamber, said pressure governin chamber being located at a height above saidfeeding chamber producing a gravity head correspondm with the emergency pressure in said tan to effect the feeding of said sup plemental acid charge from said feeding chamber into said tank by the plunger action of the mercury from said pressure overning chamber when the tank pressure ills below the normal emergency pressure.

7. In fire extinguishing apparatus, a sup plemental supply of extinguishing liquid adapted to be connected to'the distributing system and, con'iprising a chemical mixing tank charged with chemical and means to cause an emergency pressure in said tank, and means to maintain the emergency pressure in said tank comprisin a supplemental acid feeding chamber having a discharge passage connnunicating with said, tank, a governing transfer pipe connected, to the lower partof said feeding chamber, a pres sure governing chamber connected to said governing transfer pipe and located above said feeding chamber, a charge of mercury normally located in said feeding chamber, a supplemental charge of acidin contact with said mercur in said feeding chamber to effect the fee ing of said supplemental acid charge from said feeding chamber into said tank by the plunger action of the mercury from said pressure governing chamber when the tank pressure falls below the normal emergency pressure.

, 8. In fire-extinguishing apparatus, a dis tributing system comprising automatic distributing devices, a supplemental supply of extinguishing liquid connected to said system and comprising a chemical mixin pressure tank and cooperating mixing devices including a starting device comprising a starting acid chamber having a starting charge of chemical therein and connected means actuated on the emergency condition of said system to discharge said starting charge'into said tank and means to maintain the emergency pressure in said tank comprising a supplemental chemical holder formed with a depending discharge ipe, a sup lemental chemical feeding chain er into w ich said discharge pipe projects and havin a discharge passage communicating with said located in said feeding chamber and closing the depending end of said discharge pipe, a supplemental charge of chemical 1n said supplemental holder and retained therein by said mercury, said pressure ggverning chamber bein of such size as to e substantially filled wit the mercury forced thereinto when said discharge pipe is first uncovered and being located at a height above said feeding chamber producing a, gravity head corresponding with the emergency pressure in said tank to effect the forcing of said mercury into said pressure govermn chamber under emergency conditions to al ow said suppleental charge to enter said feeding 0 amlier and be subsequently fed therefrom into said tank by the plunger action of the mercury rom said pressure foverning chamber when .the tank pressure alls below the Inormal emergency pressure, and a check valve in said governing transfer pipe automatically closing to form a restricted passage for said mercury into said feeding chamber.

' 9. In the extinguishing apparatus, a dis- ,tributing system comprising automatic dis- .tem and comprising a chemical mixin pressure tank and coiiperatm including a starting device comprising a tributing devices, a supplemental supply of extinguishing liquid connected to said. sysmixing evices starting charge of chemical therein and connectcd means actuated on the emergency condition of said system to discharge said starting charge into said tank and means to maintam the emergenc pressure in said tank comprising a supp emental'chemical holder formed'with a depending dischargepipe, ,a supplemental chemical feeding chamber into which said discharge pipe projects and having a discharge passage communicating with said tank, a governing transfer pipe connected to the lower part of said feeding chamber, a pressure governing chamber connected to said governin transfer pipe and located aboye said fee mg chamber,.an over-pressure device pipe conpected to said governing transfer pipe, acnarge of mercury normally located in said feeding chamber and closing the depending end of said d scharge pipe, a supplemental charge of chemical in said supplemental holder and retained therein by said'mercury, said pres ure governing chamber being of such siz asto be substantially fillet. -.h the m rcury forced thereinto when said discharge pipe is first uncovered and being locate! ata height above said feeding chamber producing a gravity head corresponding with the emergency pressure in said tank to vll'cct the forcing ofsaid'mercury into said ressure governing chamber under emergency conditions to allow said supplemental charge to enter said fer Zing chamber and be subsequently fed therefrom into said tank by the plunger action of the mercury from'said pressure governin chamber when the tankpressure falls be ow the normal emergency pressure.

10. In fire extinguishing apparatus, a d stributing system comprising automatic distributing devices, a supplemental supply of extinguishing liquid connected to said system and comprising a chemical mixin pressure tank and coiiperating mixing evices including a starting device comprising a starting charge of chemical therein and connected means actuated on the emergency condition of said system to discharge said starting charge into said tank and means to maintain the emergency pressure in said tank comprising a supplemental chemical holder formed with a depending discharge pipe, a supplemental chemical feeding chamber into which said discharge pipe projects and having a dischar e passage communicatin with said ta a governing transfer pipe connected to the lower part of said feeding chamber, a pressure governing chamber connected to said governing trans fer pipe and located above said feeding chamber, a charge of mercury normally located in said feedin chamber and closing the depending end 0 said dischar e pipe, a supplemental charge of chemica in said supplemental holder and retained therein b said mercury, said pressure governing c iamber being of such size as to be substantially filled with the mercury forced thereinto when said discharge pipe is first uncovered and being located at a height above said feeding chamber producing a gravity head correspondin with the emergency pressure in said tan to effect the forcing of said mercury into said pressure governin chamber under emergency conditions to a feeding chamber and be subse uently fed therefrom into said tank by t e plunger actionof the mercur from said pressure overning chamber w en the tank pressure alls below the normal emergency pressure.

11. In chemical pressure devices adapted for use in automatic fire extinguishing appa- Iatus, a chemical mixin tank charged with pressure producing c emical, means to maintain t 10 pressure in said tank comprising a supplemental chemical feeding chamber containing a cooperating chemical charge having a discharge passage communicating with said tank and coiiperating chemical dischar ing means comprising a governing trans er pi e connected to the lower part of said feeding chamber, a pres sure governing chamber connected. said governing transfer pipe ,yand located above said feeding chamber, an over-pressure reser'voir pipe connected to J said governing transfe; pipe and extendm'ga bove said wres sure governing chamber, a charge of liquid of greater specific gravity than said chemical charge and normally located in said feeding chamber, said pressure governing chamber being of such size as to be substantially filled when the liquid is first forced thereinto and being-located above said feed ing chamber to produce a pressure corresponding with the desired pressure in said tank to effect the forcing of said liquid into said pressure governin chamber under the desired pressure conditlons and to eflect the feeding of chemical into said tank by the plunger action of the liquid from said pres sure governing chamber when the tank pressure ails below the desired ressure.

12. In chemical pressure evices adapted for use in automatic fire extinguishing apparatus, a chemical mixing tank charged with pressure producing chemical, means to maintain the pressure in said tank comprising a supplemental chemical feeding chamber containing a coiiperating chemical charge having a discharge passage communicating with said tank and cotipcrating chemical discharging means comprising a governing transfer pipe connected to said feeding chamber, a pressure governing chamber c0nneeted to said governing transfer pipe and located above said feedin chamber, an overpressure device connecte to said governing transfer pipe, a charge of liquid of greater specific gravity than said chemical charge and normally located in said feeding chamber, said pressure governing chamber being located above said feeding chamber to produce a pressure corresponding with the desired pressure in said-tank to effect the forcing of said liquid into said pressure governing chamber under the desired pressure conditions and to effect the feeding of chemical into said tank by the action of the liquid from said pressure governing chamber when the tank pressure falls below the desired pressure.

13. In chemical pressure devices adapted for use in automatic fire extinguishing ap paratus, a chemical mixing tank charged with pressure producing chemical, means to maintain the pressure iii said tank comprising a supplemental chemical feeding chamber containing a cooperating chemical charge having a discharge passage communicating with said tank and cooperating chemical dis charging means comprising a governing transfer pipe connected to said feeding chamber,a pressure governing chamber connected to said governing transfer pipe and located above said feeding chamber, a charge of liquid of greater specific gravity than said chemical charge and normally located in said feeding chamber. said pressure governing chambcrbeing located above said feeding chamber to produce a pressure corresponding with the desired pressure in said r tank to effect the forcing of said liquid into said pressure governing chamber under the desired pressure conditions and to efiect the feeding of chemical into said tank by the action of the liquid from said pressure overning chamber when the tank pressure alls below the desired pressure.

14. In automatic fire extinguishing apparatus, a distributing system charged with extinguishing liquid and comprising auto matic distributing devices, a supplemental supply'of extinguishing liquid connected to said system and comprising a chemical mixing tank charged with carbonate extinguishi, ing liquid and coiiperating mixing devices including a starting device comprising a starting chamber having a starting charge of acid chemical therein and having a discharge passage communicating with said tank, a restraining device cotiperating with the discharge passage of said starting device and comprising an actuating pressure pipe connecting said restraining device and said distributing system, to prevent discharge of said starting charge into said. tank under normal conditions, and to effect the discharge of said starting charge into said tank under lire emergency conditions to generate of sa'id starting device and comprising an actuating pressure pipe connecting said restraining device and saiddistributing systeln, to prevent discharge ofsaid starting charge into said tank under normal conditions, and to effect the discharge of said starting charge into said tank under fire emergency conditions to generate emergency pressure therein.

16. In fire extinguishing apparatus, a distributing system comprising distributing (levices, a supplemental supply of extinguishing liquid connected to saidsystem and comprising a chemical mixmg tank charged with extinguishing liquid and cofiperating mixing devices including a starting device comprising a starting chamber having a starting charge of chemical therein and having a discharge passage communicating with said tank, a restraining device cooperating withthe discharge passage of said starting device and comprising anactuatin pressure pi connectin said restraining evice and said" distributing system to "prevent dis- /charge of said starting chargeinto said tank under normal conditions, and to died the discharge of said starting charge into said tank under fire emergency conditions to generate emergency pressure therein.

17. In fire extinguishing apparatus a distributing system comprising distributing devices, asupplemental sup y of extinguishing' liquid connected to sai system and comprising a chemical mixin tank' 'and coiiperating mixing devices inc uding\a starting device comprising a startin chamberhaying a startin c arge of c cmical therein and having a discharge passage communicating with said tank, a-restrainmgdevice connected with said system and with the discharge passage of said starting device and comprisi' Jan actuating pressure pipe connectlng sa d-restraining device and said distributing system a to recent discharge .of said startin charge into said tank under normal -e lri0n23 ""fll'ldt0' eiiect the dis charge of said starting charge into said tank under fire emergency conditions to generate emergency pressure therei i i 18. In nutoltmtic fire extinguishing apparatus, a distributing system charged with extinguishing liquid and comprising distribiit'ing devices including automatic sprinkler heads. a supplemental supply of extinguishing liquid connected to said so stem and comprising a chemical mixing tan charged with extinguishing liquid and cooperating mixing devices" including a starting device cumprisin a starting chamber having a startingc a'rge ofphenricartherein and hav in; a discharge vpassagc farmed with 41 trap and communicatingwith said tank, a restraining device connected with said starting device rind with said system and comprising an actuating chamber and an actuatinu transfer pi e connecting said actuating; chamber and said trapi 'an actuating pi-cssu'rt'r pipe connecting said actuating rluunhcr m1 said distributing system. a clnirge of heavy liquid normally forced into said actuating transfer pipe and trapto form a restraining liquidseal preventing discharge of said start ing charge of chemical into said tank under normal conditions. said seal being withdrawn from said trap into said actuating cliamberunder (uncrgcncy conditions to effect the rapid discharge of said starting charge into said tank togcncratc emergency pressure ther'eiu. and means to maintain the emergency pressuriin said tank comprising a supplemental tlicmiclil charge and coiiperating means to gradually teed said"supplemental" charm into said tank creases. I a '19. In mltomatic fire extinguishing apu'hcn the pressure thcrcin dcparatus, a distributing system char with extinguishing liquid and comprisiiig distributing devices, a supplemental supply of extinguishing liquid connected to said systeni and compris ng a chemical mixing tank charged with extinguishing 1i aid and 00- operating mix Q g devices inclu ing a starting device co prising a starting chamber having a starting charge ofchemical therein and having a discharge passage formed with a trap and communicating with said tank, a restraining device connected with said starting device and with said system and comprising an actuating chamher and an actuating transfer pipe connecting said actuating chamber and said trap an actuating pressure pipe connecting said actuating chamber and said distribut ing system, a charge of heavy liquid normally forced into said actuating transfer pipe and trap to form a restraining liquid seal preventing discharge of said starting charge into said tank under normal conditions, said seal being withdrawn from said trap into said actuating chamber under emergency conditions to effect the rapid discharge of said starting charge into said tank to generate emergency pressure therein.

20. In fire extinguishing apparatus, a distributing system comprising distributing de vices. a supply of extinguishing liquid connected to said system and comprising a chemical mixing tank charged with extinguishin'g liquid and coiiperating mixing devices including a starting device comprisinga stnrtingchamber aving astarting charge of chemical therein and having a discharge passage formed with a trap and comnmnicating with said tank, a restraining device connected with said starting device and with said system and comprising an actuating, chamber and can actuating transfer pipe connecting said actuating chamber and said trap, a charge of heavy liquid normally forced mto said actuatin transfer pipe and trap to form a restraining liquid seal preventing discharge of said starting charge into saidtank under normal conditions, said seal being withdrawn from said trap into said actuating chamber under emergency conditions to effect the rapid discharge of said starting charge into said tank to generate emergency pressure therein.

2]. Tu fire extinguishing apparatus, a dislrilmting system comprising distributing derives, a supply of extinguishing liquid runnrrlrd to said system and comprising a ci vl'nirful mixing tank and coiipcrating mixing dcviccs including a starting device com prising! a starting chgunbcrhaving a startlug: -lmrgc of chemical tlwrelu and having a discharge passage formed with a trap and communicating with said tank, and a resirnining drvicc connected with said starting device and with said systci n andcom- 1 ,aeasea prising a charge ofhcavy liquid to form a restraining liquid seal preventing discharge of said starting charge into said tank under normal conditions, said seal being withdrawn from said trap to effect the discharge of said starting charge into said tank to generate emergency pressure therein. Y

22. In fire extinguishing apparatus, a dis ributing systemcomprising distributing devices, a supply of extinguishing liquid connected to said system and comprising a chemical mixing tank charged with extinguishing liquid and cotiperating mixing devices including a starting device comprising a starting chamber having a starting charge of chemical therein and having a discharge passage formed with a trap and communieating with said tank, a restraining device connected with said starting device and with said system and comprising an actuating chamber and an actuating transfer pipe connecting said actuating chamber and said trap, and a charge of mercury normally forced into said actuating transfer pipe and trap to form a restraining mercury seal preventing discharge of said starting charge into said tank under normal conditions, said seal being withdrawn from said trap into said actuating chamber under emergency conditions to effect the rapid discharge of said starting charge into said tank to generate emergency pressure therein.

23. In fire extinguishing apparatus, a distributing system comprising distributing devices, a supply of extinguishingliquid connected to said system. and comprising a,

chemical mixing tank and coiiperating mix-- ing devices including a starting device prising a starting chamber having a starting charge of chemical therein and having a discharge passage formed with a trap and communicating with said tank, and a restraining device connected with said starting device and with said system and comprising a charge of mercury to form a restraining mercury seal preventing-discharge of said starting charge into said tank under normal conditions, said seal being withdrawn from said trap to efl"ect the discharge of said starting charge into said tank to generate emergency pressure therein.

24. In automatic fire extinguishing apparatus, a distrihutii'ig system charged with non-freezing extinguishing liquid and comprising automatic distributing devices ineluding automatic sprinkler heads, a supplemental supply of extinguishing liquid connected to said system through a rented valved connection. and comprising a chen1ical mixing tank charged with carbonate ex; linguishiug liquid and cotiperating mixing devices including a starting device comprising a starting acid chamber lined with a. neutral resistant coating and having a starting charge of acid therein and having a discharge passage ,formed with a trap and communicating with said tank, a restraining device eotiperating with said starting device and comprising an actuating chamber below said trap and an actuating transfer pipe connecting said actuating chamber and said trap, an actuating pressure pipeconnecting said actuating chamber and the upper part of said distributing system, a charge of mercury normally forced into said actuating transfer pipe and tra to form an acid restraining mereury seai of said starting charge of acid into said tank under normal conditions, said mercury seal being withdrawn from said trap. into said actuating chamber under emergency conditions to effect the discharge of said acid into said tank to generate emergency pressure therein. i

25. In automatic fire extinguishing appar'aitus, a distributing system charged with extinguishing liquid and comprising automatic distributing devices, a supplemental supply of extinguishing liquid connected to said system and comprising a chemical mixing tank charged with carbonate extinguishing liquid and cotipcrating mixing devices including a starting device comprising a starting acid chamber having a starting charge of acid therein and having a discharge passage formed with a trap and commumcating with said tank, a restraining de-. vice coiiperating with said starting device and comprising anactuating chamber below said trap and an actuating transfer pipe connecting said actuating chamber and said trap,

an actuating pressure pipe connecting said preventing discharge actuating chamber and the upper part of said distributing system, a charge of mercury normally forced into said actuating transfer pipe and trap to form an acid restraining mercury seal preventing discharge of said starting charge of acid into said tank under normal conditions, said mercury seal being withdrawn from said trap into said actuating chamber under emergency conditions to effect the discharge of said acid into said tank to generate emergency pressure therein.

26. In automatic fire extinguishing appa- Mills. a distributing system charged with ex tinguishing liquid and comprising automatic distributing devices, a supplemental supply of extinguishing liquid connected to said system and comprislng a chemical mixing tank charged with carbonate extinguishing liquid and cooperating mixing devices in eluding a starting derice comprising a starting acid chamber having a starting charge of aeid therein and havin a discharge passage firmed with a trap an communicating with said tank, a restraining device cooperating with said starting device and comprisin an actuating chamber below said trap and an actuating transfer pipe connecting said actuating chamber and said trap, an actuating pressure pipe connecting said actuating chamber and said distributing system, a charge of mercury normally forced into sa1d actuating transfer pipe and trap to form an acid restraining mercury seal preventing dis charge of said startin charge of acid into said tank under norma conditions, said mercury seal being withdrawn from said trap into said actuating chamber under emergency conditions to efi'cct the discharge of said acid into said tank to generate emergency pressure therein.

27. In automatic fire extinguishing apparatus, a distributing system charged with extinguishing liquid and comprisingautomatic distributing devices, a supplemental supply of extinguishing liquid connected to said system and comprising a chemical mixing tank charged with carbonate extinguishing liquid and coiiperating mixing devices including a starting device comprising a starting acid chamber having a starting charge of acid thereinv and" having .a discharge passage formed-with atrap and communicating with said tank, a restraining device connected with said system and with said starting device andcomprising a charge of mercury normally forced into said actuating transfer pipe and trap to \form an acid restraining mercury seal preventin discharge of said starting charge of acid into said tank under normal conditions, said mercury seal being withdrawn from said trap into said actuatinn chamber under,emcrgcncy conditions to effect the discharge of said acid into said tank to generate emergency pressure therein.

28. In fire extinguishing apparatus, a distributing system, a supply of extinguishingliquid connected to an id system and comprising a chemical mixing tank and coiiperating mixing devices including a device comprising a chamber having a charge of pressure producing chemical th'creii i and having a discharge passage formed with a trap and mum municating with said tanln and a restraining ldcviceconnected with saiddevice and with said system andcompnising a bodyof mercury to form arestraining mercury seal preventingv discl'iarge of. said chemical charge into said'tank under normal conditions, said seal being Withdrawn from said trap to at feet the discharge of said chemical charge into said tank to generate pressure therein. 1 29, In fire extinguishing apparatus, a distributing system, asupply of extinguishing liquid connected to said system and comprising a chemical'mixing tank and (miiperating mixing devices including a device compris- (lug, chamber having a charge oi p'reisure ppoduci ng chemical therein and ham a discl arge'passage" formed with a trap and m'maai anng with said tank, and a re- "strainingdcvice connected with said device and w th saidsys tcm and comprising a body of heavy liquid to form a restrannng liquid nected with sai seal preventing discharge of said chemical charge into said tank under normal conditions, said seal being withdrawn from said trap to effect the discharge of said chemical charge into said tank to generate pressure therein.

30. In fire extinguishing apparatus, a distributing svstem a supplyof extinguishing liquid connected to said system and comprising a chemical mixin tank and coiiperitting. mixing devicesinclu in a device compris ing a chamber having a c large of-acid chemical therein and havin a discharge passage formed with a trap am communicating n h said tank and a restraining device conne d with said device and with said system nd comprising a body ofmercury to form straining mercury seal preventing dischai'ge of said acid charge into said tank under norma] conditions, said seal bein Withdrawn from said trap to efiiect the disc arge of said acid charge into said tank to generate pressure therein. 1 a l 31. In fire extinguishing apparatus, a distributing system, a supply of extinguishing liquid connected to said system and comprising a chemical mixing tank andcodperating mixing devices including a device comzprising a chamber having a charge of pres sure producing chemical therein and having a discharge passage formed with a trap and communicating with said tank, and a restraining device connected with said device and with said system and comprising a body of heavy liquid to form a restraining liquid seal preventing discharge of said chemical charge into said tank under nor mal conditions and means controlled by said system to withdraw said seal from saidtrap to effect the discharge of said chemical charge into said tank to generatev pressure therein.

32. In fire extinguishing apparatus, a disv tributing system, a supply of extinguishing liquid connected to said system and'comprising a chemical mixingtank and cotiperat inn mixing devices including a device comprising a chamber having a char e of acid chemical therein' and having a disc ar e passage formed with a trap and communicating with said'tank, nd arestraining device condevice andwith said systom and; comprising a body of mercury to form a restraining mercury seal reventing discharge of said charge into said tank under normal conditions, and means controlled by the pressure conditions or said distributing system to withdrawsaid sea] from said. trap to efl'ect the discharge ofsaid acid charge into said tank to generate pressure therein. A

33. Inchem'ical fire estinfiaishing, apparatus, a chemical ixing tan charged with pressure produci g, chemical, means to cause tank comprising a, chemical feeding chamber containing a cotiperating chemical charge and having a discharge passage communicating with said tank and cooperating chemical discharging means com rising a governing transfer pipe connects to said feeding chamber a pressure governing chamber connected to said overning transfer pipe, an overpressure device connected to said governing transfer pipe, a charge of liquid of greater specific gravity than said chemical charge, and adapted to move through said transfer governing chamber and her, said prewure governin chamber being located above said feeding c amber and producing a pressure corresponding with the desired pressure in said tank to efi'ect the forcing of said liquid into said pressure governing chamber under the desired pressure conditions and by displacement to effect the feeding of chemical into said tank when the tank pressure falls below the desired pressure.

34. In chemical fire extinguishing apparatus, a chemical mixing tank charged with pressure producing chemical, means to cause and maintain the operating pressure in said tank comprising a chemical feedin chamber containing a cooperating chemica. charge said feeding chamand having a discharge passage communi-.

eating with said tank and cooperating chemical discharging means comprising a governing transfer pipe connecte to said feeding chamber, a pressure governing chamber connected to said overnlng transfer pipe, a charge of liquirf of greater specific gravity than said chemical charge and adapted to move through said transfer pipe between said overning chamber and said feeding cham er, said pressure overning chamber being located above sai feeding chamber and producing a pressure corresponding with'the desired pressure in said tank to effect the forcing of said liquid into said pressure governing chamber under the desired pressure conditions and by displace ment to efi'ect the feeding of chemical into pipe between said said tank when the tank pressure falls below the desired pressure.

35. In chemical fire extin uishing apparatus, a chemical mixing tank charged with pressure producing chemical, means to cause and maintain the pressure in said tank comprising a chemical feeding chamber containin a coiiperating chemical charge and a apted to dischar e into said tank and cooperating chemica discharge means comprising a charge of liquid of greater specific gravity than said chemical charge and means to effect the entry of said liquid into said feeding chamber and by displacement to effect the feeding of chemical into said tank when the ressure in the apparatus falls below the esired pressure.

36. In chemical fire extinguishing apparatus, a chemical mixing tank charged with pressure producing chemical, means to cause and maintain the pressure in said tank comprising a chemical feeding chamber contain ing .a cooperating acid chemical charge and adapted to discharge into operating chemical discharging means, c0mprising a charge of mercury and means to efl'ect the entry of said mercury into said feeding chamber and by displacement to effect the feeding of chemical into said tank when the pressure in the apparatus falls below the desired pressure.

37. In chemical fire extinguishing apparatus, a chemical mixing tank charged with pressure producing chemical, means to cause and maintain the pressure in said tank comprising a chemical feeding chamber containin a coiiperating chemical charge and a apted to discharge into said tank and cooperating chemicaldischarging means comprising a charge of mercury and means actuated by the weight of said mercury to effeet the feeding of chemical into said tank when the pressure in the apparatus falls below the desired pressure.

JOHN R. HAMILTON.

Witnesses HARRY L. Duncan, Jnssm B. KAY.

said tank and co--

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