US1120571A

US1120571A - Water-heater construction.

Info

Publication number: US1120571A
Application number: US74419813A
Authority: US
Inventors: Frank L O Wadsworth
Original assignee: Individual
Current assignee: Individual
Priority date: 1913-01-25
Filing date: 1913-01-25
Publication date: 1914-12-08
Anticipated expiration: 1931-12-08

Description

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.".DJANZLINS Patented Dec, 8. 1914.

3 *LHLETS SHEETS F. L. 0. VVADSWORTH.

,MTBE HEATER APPLICAIION YH fair www/",

Mu /1 v f FRANK L. 0. WADSWORTH, OF SEWICKLEY, PENNSYLVANIA.

WATER-HEATER CONSTRUCTION.

. Specification of Letters Patent.

Patented Dee. 8, 1914.

Application filed January 25, 1913. Serial No.r 744,198.

To all whom t may concern Be it known that I, FRANK L. O. WADswonrn, a citizen of the United States, residing at Sewickley, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful mprovements in Water-Heater Construction, of which the following is a specification.

My invention relates to the automatic control mechanism for regulating the supply of fuel to the burner system of Water heaters, particularly heaters of the so-called instantaneous type in which gas is burned only when water is iowing through the heat-er coils. One ofl the principal objects of my invention is to produce a mechanism by which the movements of the single main fuel valve are synchronously, but indirectly controlled, (first) by the movements of a water-actuated element in such manner that said fuel valve is caused to open when a flow of water is started through the heater and caused to close when said flow is stopped, and ,(second) by the movements et' athermostatl member in such vmanner that the fuel valve is caused to close when the temperature of the flowing water rises above a certain point and caused to open when the temperature of the water flowing out of the heater fallsbelow a certain point. T his general result has been se cured by various previously described forms ot' mechanisms; such Jfor example as those shown in my (zo-pending applications Ser; Nos. 727,51() and (359,516, filed on October 24, 1912 and November 10, 1911 respectively. Uiut in general such mechanisms are designed to act directly on the main gas valve; that is to say, are designed to produce by. the direct movements of the water-actuated member and the thermostat member a corresponding direct movement of the main Jfuel valve. ln my present invention, as above indicated, there is no such direct connection between the operating parts. Instead of this, l use the movements both of the water-:actuated member and the thermostatically actuated member to simply control the application et a force which is independent ot' either of these power-actuated elements; this torce being produced by or derv 'ed from the pressure of the gas in the maih `fuel supply pipe, or-the pressure of the water in the heater (either the static pressure or the dynamic liow pressure) or a source oli electro-magnetic energy, or some other suitable power developing means.

character above mentioned will be readily apparent to those skilled in the art from the following descriptions of various embodiments of my present invention. Y.

In the drawings which form a part of this specification,I Figs. l and 2 illustrate in front and side elevation respectively the general construction of a hot water heater of the socalled instantaneous type; Fig. 3 is an enl larged cross-sectional view through the center of the control mechanism used in the construction of Figs. 1 and 2; Fig. i illustrates a modified construction and arrangementl of some of the parts shown in Figs. 1, 2 and 3; Fig. 5 is a similar cross sectional View through the center of another control mechanism embodying my improvements; Figs. (3, 7 and 8 are sectional illustrations of other embodiments of my invention. r

Referring first to the general arrangement of the heater parts as shown in Figs. 1 and 2; A is the casing of the heater; B indilfates the upper coils of the heater; C is the lower reverse coil connected to the upper coils by means of the pipe D; E arel the gas burners mounted upon the usual burner ring; F is the gas supply pipe; G is the easing of the gas valve for controllingthe supply of gas to the burners; H is the gas pipe leading from the gas valve to the ring which carries the burners E; Ifis the casing of the thermostat; and K is the casing of the water actuated member for securing the operation of the gas valve when the outlet from the heater is opened and closed.

Referring now to Fig. 3 in conjunction with l igs.'1and 2; 1 indicates the pipe through 4which cold water passes Jfrom the main to the chamber 2 containing the wateractuated member of the control :mecha-mism; S indicates the water inlet to the top heater coil A; 4 indicates 'the outlet from the bottom reverse coil C of the heating receptacle, this latter outlet communicating through ports 5, 5, etc., with the lower end of the vertical thermostat chamber 6; and 7 indicates the pipe leading from the upper end of said thermostat chamber to the house supply system. The gas, or suitable fuel,l

which supplies the main heating burners'F is led into the controlapparatus throu h a' pipe F to the main gas valve casing in which is located the valve 8 which controls the flow of fuel through the pipe I leading to the heating burners Ef This valve 8 is mounted on and supported by a thin flexible diaphragm 9, made of leather, parchment,'

metal foil, or other suitable material, which in this case, is of considerably larger diam` eter than the' valve 8 and is clamped in1 position between the open side of the main gas valve casing G and a shallow recessed cap 10, This cap 10 is provided on -its central vertical diameter with a tubular enlargement or cavity 11 having port openings 12 and 13 at the top and bottom which afford communication between the shallow space 10k-e'. e., to the rightof ine diaphragm member 9 and passage-ways 14 and 15 that leadl respectively to the interior of the gas inlet l-pipe F and to the gas outlet pipe H. r1`he ports 12 andl 13 are opened and closed by means of two

valves

16 and 17 mounted on a common stem 13 which passes upthrough a stufing boX above the port 12 and terminates opposite an adjustable screw 19 vin the endl of the lever 20 whose movement is controlled by the thermostat. Thr stem 13 and valves 16 and17 are normally held in the position shown in the figure-in which the port 13 is closed and the port 12 is opened-by means of a spring 21. The .thermostat by means of which the lever 2U is operated is of the gene eral construction more fully illustratedand described in my co-pending application Serial No. 699,316. The positive expansion member of this thermostat consists of a wire 22 of hard drawn copper, brass, vphos- .phor bronze or similar suitable metal, which is secured at one end at the point 23, is led successively around the steps of lower and upper coned pulley .elements 24 and 25, is then led 'out through a stuiiing box 26 in the lower head of the thermostat chamber 6, and secured to a collar-27. A.

knife edge 23 bearing on `the lower side of the lever 2O is threaded on the wire just above the collar 27 and a short compression spring y23 isinterposed between the-knife edge and said collar to provide for a small `relative movement of one with respect to the other. A tension spring 29 secured to the thermostat lever 20 serves to keep the wire 22 under practically constant tension as it expands and contracts with changes of temsupported in position on a post 31 bolted to the lower head of the thermostat chamber 6. 1t is apparent that the expansion and contraction movements of the successive strand sections of the .wire 22 which pass between the upper and lower pulley elements are cumulative in effect and the diameters of the successive steps of the pulley elements 24 and 25 are in the ratio of the odd numbers', 1, 3, 5, etc., for the lower element, 'and are in the ratiotf. the even numbers, 2, 4, 6, etc., for the upper element, so` that there is no slip between the various parts of the wire 22 which lie on these steps and the steps themselves. Hence the movement of the collar 27 at the lower end of the wire 22 under ay given change in temperature is the same as that of a straight wire secured at its other end to a point on a nickel steel or invar metal pipe leading up from the lower end of the chamber, and of a length equal to the sum of the lengths of all the successive strand sections. The construction above Adescribed enables me to use in the relative short thermostat chamber 6 such a total effective length of wire as will eliminate the necessity of employing any large multiplication of the thermostat lever system in order to secure theV necessary movement of the screw 19 which acts upon the stem of the

valves

16 and 17; and therefore enables me to produce, the very simple and compact arrangement of parts shown in Fig. 3.

The outer end of the passage-way 14v which leads into the gas supply pipe H is opened and closed by a valve 32 which 1s secured to the lower end of a stem 33 that passes upward through the vertical section of the pipe H, through a stuiing boX at the top of that section, and through an adjathe port opening 36 leading from thecham#l ber 2 to the upper end of the thermostat chamber 6.

The operation of this mechanism is as folllows: When no water is flowing through the heater, the valve 32 is held against its seat bythe weight of the stem 33 and valve head 34e-supplemented if desired by a compression spring such a's that shown at 374- and the closure of this valve prevents any gas from entering the chamber 11 at the right hand side of the diaphragm 9, even though the port 12 may be open. Under such circumstances the diaphragm 9 is eX- posed to the gas pressure only on the left hand side, and this pressure holds the main gas valve 8 against its scat thus preventing any fuel passing through it to the main heating burners. But as soon as the flow of water through the heater is started-as by opening a tap inthe house supply systemthe pressure on the upper side of the puppet valve 3iis reduced by the outflow of water, and this puppet valve will be raised, opening the valve 32 and closing the valve 35. The opening of the former valve allows the gas to iow into the chamber ll-it the port 12 is open at that time, as it will be it the temperature of the water in the thermostat chamber is below the predetermined point ot' cutoff-and this inflow of gas to the chamber l1 equalizes the pressure on the two sides of the diaphragm member 9, thus allowing the gas valve 8 to be opened by the unbalanced pressure of the gas on its right hand side. As the temperature of the water in the thermostat chamber rises the wire 22 will expand allowing the lever 20 to be pulled down by the tension of the spring 29 until the screw 19 engages with the end of the valve stem 18 thus closing the port 13. When this occursthe gas back of the diaphragmg-z'. e., ori/the right hand side,-iows out through the passage vay 15 Aand the ejector orifice at the end of that 'Jassage-wa into the @as outlet vwie This once more relievesthe pressure on the right hand side of thc diaphragm 9. ad the unbalanced pressure of the gas on the left hand side closes the valve S and cuts ci? a further flow of :fuel to the main-burners o1"- the heater. Any slight expansion of the thermostat wire 22 which takesgplace after the seating ot the valve/16 is talren care ot by the expansion ot' the spi-'ing bctwe'cn the collar 27 and the knife edge 25%, so that the wire 22 is manuained constantly under tension. lVherlfllie temperaturel of the flowing water falls again the wire 22 will contract lifting the lever 2O against the tension. ot' thedspring 29 and freeing the stem 18 from" engagement with the screw 19. The valve stem 18 and the

valves

16 and 17. will than be raised bythe tension f ol' lhespring 21 thus closing the port 13 and opening,y the port .12. This restablishes -equal gas pressures on the two sides oi the 'ancing of the gas pressure on the two sides of the diaphragm member 9 whenever the temperature of the water inthe thermostat ber 11 is filled with gas, the gas valve, of. course, remains open until the water in the apparatus has been heated up to the point ot' cut-off and the port 13 is opened. The gas .remaining in the chamber 11 will then flow out and the main gas valve 8 will be permanently closed until a fresh actuating supply ot' gas has been admitted to the chamber 11 by the opening of the water 'cor trolled valve Vhen the valve 3l is closed, the valve 35 is always open thus allowing the water to circulate freely through the thermostat chamber (3 between the inlet and outlet openings 3 and l of the heater coils.

In el I have illustrated invertical cross-setion another forni of my improved control mechanism. In this construction water flows from the main through the pipe 1I to the chamber 2 and thence directly into the inlet 3 communicating with the top coil A of the heating receptacle. After flowing through the successive coils A ,to C, the water emerges 'from the outlet Ll', enters the lower end oil: the thermostat chamber 6', and after flowing` upwardly through said chamber, enters the pipe 7 leading to the desired "point of discharge. At the upper end of the thermostat chamber l provide a portv S6 which leads into the chamber 2. This port is opened and closed by va valve Al()v held in position' by wings engaging with the sides ci" the port 36 and b v a stem, the end ofv which enters a recess al in the wall oi' the thermostat chamber. When no water is flowing through the apparatus, this valve is held open by. means of a. weak spring l2,

thus allowing the water to circulate freely.

tl'iroiigh the thermostat chamber G and the port 3G between thejnlet 3 and the outlet l of the heater coils. The vfuel supply enters the main gas vlilve casing G through a pipe l? and passes out-when the main gas valve S is opened-through the `pipe 7 `which leads to the main burners of the heater. A cut-off valve 42 is inserted in the inlet pipe l1" as usual, and the inlet side of this valve is provided with a connection from whiclrthe pipe LL3 passes to the usual pilot light` The main gas valve S is in this construction supported on a stem 44 which passes 'through a stuiling box in the right hand wall of the gas valve fasing G and is attached at its outer end to the center ofthe thin flexible diaphragm member-all?. The

55 lever 56 serves to keep said lever in. operagas valve 8 is not secured directly to the stem 44 but is held in position against the inner head thereof by means of a leaf spring 46 which permits the stem 44 to move slightly with relation to the gas valve, the

` said space to an ejector outlet 38 that enters the gas outlet pipe H. The openings `from the passage-ways 14 and 15 `to the chamber 48 are controlled by

valves

16 and 17 which are mounted on a valve stem 18 (forked atV its center to pass around the stem 44) and are normally held in the position shown in the figure, in which'the valve 16 is open and the valve 17 is closed, by a compression spring 21. The outer end of the passageway 14 is also closed by another valve 32 mounted on a stem- 31 which passes up through a stuffing box in the top cap of the gas valve casing G', then through a second,

stuiiing box in the lower end et the cylinder 49 and is secured to the water-actuated piston member 50 in said cylinder. rEhe lower end of the cylinder 49 is connected to the chamber 2 by means of a pipe 51, and the upper end of said cylinder is connected to the thermostat chamber 6 by a port or passage way 52. The piston member 50 is normally held in its lowest position, in which the valve 32 is closed by means of a compression spring 53. The actuating thermostat member` which I use in this case to control the movements of the

valves

16 and 17, is'of the usual composite construction, save that the outer expansion tube 54 and the inner negative element may both be made very light because the thermostat member does not have to move'the auxiliary controlled valves just mentioned. The lower -knife edge terminal of the inner negative element 55 bears against the short arm of a bell crank lever 56, and the long arm :et said lever is provided with an adjustable screw 57 which bears in turn upon the short arm of a secondbell crank lever 58. rlhe longer arm of the lever 58 is also provided with an adjustable screw 60 which engages with the lower end of the'stem 16. A spring 59 attached to the lower end of the tive engagement with the negative thermostat element 55.

The operation of thisvmechanism is in general similar to that already described. When no water is flowing through the ports, the piston 50 will be held down by the spring 53 and the valve 3Q will be closed, preventing any gas from flowing into the` chamber 48. But as soon as a How of water is started through the apparatus by opening some outlet in the pipe 7 the pressure on the upper side of the piston 50 is diminished v and the superior pressure of the inflowing` gasl will liow on through the passage-Way 14 to the chamber 48 and exert a pressure on the inside ot the diaphragm 45 sufficient to overcome the tension of the spring 47 and thus open the main gas valve 8 allowing fuel to ll ow past said valve through the outlet pipe I to the main burnersl of the heater,

As the temperature of the flowing water rises, the thermostat member 54 will expand, lifting the negative `member 55 and allowing the spring 59 to move the thermostat lever 5G-and with it the lever 58-until the screw 60 has been brought into engagement with the lower end of the vstem 18. The further movement of the thermostat parte inthe same direction will lift the valve 17 from its seat-'the tension of the spring 59 being sufiicient to overcome the tension of the spring 21-and simultaneously close the valve 16. This will allow the gas in the chamber 48 'to escape through the ejector orifice 53S and relieve the pressure on the inside of the diaphragm 45.' The gas valve.

8 will then be closed by the spring 47 thereby shutting oi'i1 further iiow of fuel to the main burners. The main' `gas valve 8 will remain closed until 'the itall in temperature of the flowing water has caused the partsl) once more assume the position shown in the figure in which the valve 16 is open and thevalve 17 is closed. 1n this position-'the valve 32 being still cpcn--a fresh supply of gas is admitted to the chamber48 and the pressure on the inside of the ldiaplfnragln 45 reestablished, thereby again opening the main its lowest position thereby closing thevalve 32 and preventing any further access of gas to the chamber 48.

1l4 is prevented, when the gas valve is closed, by a leather washer 61' which is liept tightly pressed against the head of the valve stem stuiling box by means of a springe,n 46 and thus seals the opening around this stem against any escape of gas even though the Any leakage of gas through the stufling box around the stem stufiing boX itself may be quite loose. It the main gas valve is open when the water is shut eff, and the valve 32l is closed, it

will remain open until the temperature of0 close and remain closed until w; t. r has once more started to flow through the neater and has opened the valve 32, admitting gas once more to the chamber 48. In Fi 5 I illustrate still another embodiment oi my invention, which diHers from those previously described in the detail form of the water-actuated member and the thermostat member. In the construction of Fig. 5, water is brought to the apparatus through a pipe 12, the upper part of which is led directly to the cold water inlet (not shown in this figure) of the upper coil B of the heating receptacle. This pipe 12 is provided4 with a special elbow connection having a port opening 62 which registers with a correspond-ing port 63 that enters the right hand end of l the chamber 64. This chamber contains the ,water-actuated element 65, which ind this case is made in the form of a thin corrugated fiexible diaphragm of hard rolled brass or copper sheeting or some similar suitable material. A stem 332, secured to the center of this diaphragm member, is led through suitable stuffing boxes in the head of the chamber 64 and the adjacent headv of the main gas valve casing `G2 and terminates in a disk valve 322 that controls the port opening from the inlet side of the gas valve chamber G2 to the passage way 142. The dia.- phragm" member 65 is normally kept in the position shown in the igure, in which the valve 322, is seated by a compression spring 532. lThe passage-way 142 leads to a small i chamber 66 that contains the auxiliary `eon- .trolling valve 67. This valve 67 is double faced, and when down it closes the port opening 132 which communicates with the pipe 152 leading to the ejector orifice 382 that opens into the gas outlet pipe H2 leading from the gas valve chamber G2 to the main burners of the heater. l/Vhen the valve 67 is down, as shown in the figure, it opens the port connection 122. which leads from the chamber 66 to the shallow space back-z'. e., on top of-the flexible" diaphragm member 92 to the center of which the main gas valve 82 is attached.A The main gas valve 82 is in this ease arranged in a horizontal position, and opens downwardly. A weak conical spring '68 is arranged below this Valve and so adjusted in tension as to not quite support its weight. rlhe water after passing through the heating coils emerges from the lower end thereof throughthe outlet 42, enters the thermostat chamber 62 (which in this case, is formed as part of the gas valve casing G2) and emerges from the opposite end thereof through an elbow connection and pipe 72 leading to the house supply system or other desired point of discharge. A branch connection 69 leads from the outlet passage 42 to a port 522 ente-ring the left hand end of the chamber 64.A The thermostat member which I use in this case consists of two concentric corrugated metal tubes 70 and 71 which are hermetically closed at each end and theinclesed space thus formed is filled with some suitable liquid having a high coeilcient of eXpansich-preferably also of considerable viscosity such as petroleum or olive oilor filled with parafiin or some eutectie alloy that melts at a temperature less than that for which the thermostat may be desired to act. Both heads of this thermostat member are perforated at the center so as t0 allow the hot water to pass through the central opening of the inner tube 70 as well as around the exterior of the outer tube 71. The right hand head is secured in position to the cap 72 that closes the corresponding end of the thermostat chamber 62. The left hand head engages with the end of the stem 73 that passes out through a stufling box in the adjacent end of the thermostat chamber 62 and bears against the thermostat lever 562. rIhe outer end of this thermostat lever carries a double knife edge link connection 7 4 which engages with the short arm of a. second thermostat lever 582. T he long arm of this second lever is weighted to hold the lever parts in operative engagement with the stem 73, and is provided with an adjustable screw 602 that bears against the upper end of the stem 182 of the auxiliary controlled valve 67. The weight on the' end of the lever 582 normally keeps the valve 67 pressed downward against its lower seat of the port 132.` A weak compression spring 75 .is interposed between a collar on the stem 182 and the head of the stufiing boX through which said vstem passes, and acts to lift the valve 67 against its upper seatf-thus closing the port opening between the chamber 66 and the passage 122-when the screw 602 is lifted out of engagement with the/upper end oi the stem.

The operation of the control mechanism oi Fig. 5 diiers in no essential iespect from that of the previously described mechanisms, and will therefore be readily understood with a very brief description. `When no water is flowing through the apparatus, the valve 322 is held closed, thereby preventing any gas from entering the passage way 142. Under these circumstances the lower side only of the diaphragm 92 is exposed to gas pressure, and the area-otn the diaphragm 92 being considerably larger than the area of the main gas valve 82, the latter is closed against its seat Apreventing all flow of fuel to the gas outlet pipe H2. As soon as the flowof water is started, a

' differential pressure is established on the two sides of the diaphragm member` 65 by the resistance `tothe flow of water through been raised to the point of cutoff, and the will cause the diaphragm 65 to moveto the left against the tension of the spring-532, thus opening the valve 322 and allowing gas to flow into the passage-way 142. It 'the temperature of the owing /water is less than that for which the'thei'mostat is set,r

to cut off the gas supply, the gas supply valve 67 will be seated in its-lowest position,

as shown in the ligure, and the gas that flows in through the passage 14:2 will enter 15 the space above the diaphragm 92, and the main gas valve 82 will be opened, partly by the action of gravity,jand partly by the unbalanced pressure oifthe gas on its upper side, thus allowing uel to flow to the pipe H2 and thence to the main burners of the heater where it will be ignited ,by the usual -pilot light provided for that purpose. As the temperature of the flowing water is raised by the heating eiect of the main burners the thermostat member will expand moving the stem 73 to theleft and lifting the screwy 602 out of engagement with the stem 182. This will allow the spring 75 'to lift lthe valve 67 vthereby closing the port vabove the valve and opening the port 132 below thevalve. rlhe -gas above the diaphragrn 92 will then iow out through the pipe 152 yand the ejecto' orice 382 and the main gas valve 82 will be lifted by the unbalancedpressure of the gas against the lower side of the diaphragm il?. lThe gas valve will remain closed until the cooling clown of the flowing water contracts the ,thermostat member suliiciently to allow the =40 screw 602 at `theweighted en d of the thermostatlever 582 once more to engage the.

stem 182 and force down the valve 67 to the first described position. The main gas valve 82 will then againbe opened as before described. These opening and closing movements will, of course, vcontinue 'as the temperature of the flowing water successively falls below and rises above the point of predetermined cut-ol'efwhich is determined 15G-bythe adjustment of the screw 602. But

when water ceases to flow through the apparatus the pressures on the two sides of the diaphragm will once more be ecluah` ized land ysaid dia hragm-member will be --returnedjto its initial position by the action of the 'spring 532 thus closing the .Valve 322 and preventing any further access of gas to the back of the ldiaphragm member 92. lf this cut-oli by thewater-actuated memle0-ber occurs at'lthe time whenthe temperature of 'the 4flowing water is below vthe pointofthermostaticcutoi, the main gas valve 82 will remain open until the water in the heater-and the thermostatic chamber 65 which in this case is in immediate communi cation therewith-shasreached the point at which the valve 67 is raised. The gas confined above the diaphragm 92 is then discharged and the gas valve 82 remains permanently closed until the restablishment of the water flow' through the heater admits afresh supply of gasto the passageway 14:2.

ln Fig. 6 I illustrate the construction of a control mechanism in which the main gas valve is actuated/in its movement by the pressure of the water in the apparatus acting on a diaphragm to which the main gas valve is secured. The admission and withdrawal of water to and fromthe space back ofthis diaphragm ,is jointly controlled, as in previous mechanisms, by Aa set of valves. one of which is opened and closed by the starting and stopping otthelow of water through the heater, the others being opened and closed by the variations in temperature i of the flwiiig water through the medium of proper lthermostaticallyactuated mechanism. En the figure, l3 indicates the pipe leading from the water main' to the cham- `ber 22A containing the water-actuated con-- trol member A84'. This waterfactuated memberis `a puppet valve similar inform to that shown in Fig. 3 with an upper head 358 which is adapted to open and close a port 363A leading to the upper end of the thermostat chamber 63. A stein 333 is loosely secured to the lower side of the valve 348 and extends downward to a valve 323 which lis adapted to open'I and close a port leading from the chamber 23 toa water pipe 7 6 that passes downwardlto a chamber 77. In tle, lower part. of this chamber' there is aj valve '163 which opens and clhis'".-

/the outer end et a passage-way 78 leading to the banket. e., to the left handl side-of a diaphragmA 9", which in this case is of 'relatively small diameter, and is made of hea by rubber faced/.with canvas or leather, or' is made of thin-corrugated metal, 'so as to be capable of s '.tely withstanding the maximum pressure ,ato which the water in -the apparatus is. subjected. rlliefmainy gas of a strong compression spring 79." `A sec- .f

ond valve 17, locatednear the diaphragm a porty leading from` this passage-way Ato a pipe 60 which 'is preferably led downward Aadjustable screws 81 and 82, in the ends of a tw o-arnied thermostat lever 83. Mount- ,ed in the thermostat chamber 63 is the actuating therinostat member which in thiscase end of the passage-.way 7 8 opensand'closes is made up of a circular nest of iron or nickel steel tubes Si, 85, S6, etc., closed at the top and opening at the bottom into a cap 87. to the lower end of which is secured a flexible metal diaphragm box S8; the closed interior of the tubes, cap and box being iilled with a suitable positive expansion medium such as some relatively dense liquid or a solid melting at a temperatureless than that for which the thermostat may be desired to act. The lower head of the box 88 is recessed to receive the upper end of a bar 89, the lower end of which engages with the central upper knife edge slot of the thermostat lever S3. This upper knife edge slot is olf-set slightly with reference to the lower and supporting knife edge slot of said thermostat lever-so that the thrust of the bar Si) acts on a short lever arm which is inclined at an angle of 75 to 80 degrees to the long axis of the thermostat lever. l thus obtain, with a-very compact arrangement of parts, a large movement of' the 'valves 16" and 173 for the relatively very small movement of the head of the expansion box S8; and thereby secure a very sensitive regulatingr action of the thermostatic mechanism.

The operation of this mechanism is in general the same as that of the previously described mechanisms in which the movement of the main gas valve is secured by the balancing'and unbalancingof gas pressures on the main gas valve diaphragm. When no water is flowing through thevapparatus, the valve 343 is in its lowest position, the valve 323 being then closed by the pressure of the spring 90, thus cutting off all flow of water from the chamber 23 to the chamber 7 7 and thereby .preventing the pressure of ...Water in the main from acting on the rearside of the diaphragm member 9, At this time the 'fthe heater coils.

valve 353 is open allowingthe-water in the apparatus to pass freely Ithrough, the port 36 and circulate through itiliei'mostat chamber 6?l between the inlet a" and the outlet 43 of llfhcn a flow of water is started through the apparatus-as by opening an outlet in the hot water discharge pipe 73-the pressure on the upper side of the valve 343 is immediately reduced and the valve is raised from its seat, thus closing the eirculation port SGJMand simultaneously raising the valvel from its seat, thus admitting water from the main to the pipe 76 and chamber 77. lf `at this time the valve 163 is openw-a's it will be if the ,temperature of the flowing water is less than the point of thermostatic cut-oif-the water from the main will pass on through the passage-way 7 8 and exert a pressure on the back of the diaphragm member 93 suiiicient to raise the malin gas valve 83 from its seat against the tension of the'V spring 79. This will allow fuel to flow from the gas inlet pipe F3 past the main gas valve to the gas outlet pipe H3 i and thence on to the mam burners of the heater where it is ignited by the iame of the usual pilot light provided for that purpose. The gas inlet pipe F3 is of course also provided with a main cut-off valve and pilot light connection similar, for example, to that illustrated in Fig. 4, but this main cutoff valve and pilot light connection being ordinarily supplied to all mechanisms of this class, it has not been specifically illustrated in connection with either Fig. 6 or in connection with Figs. 3 and 5. As the temperature of the water flowing through the thermostat chamber rises, the liquid in the thermostat member will expand, forcing down the head of the expansion box 88 and with it the lever S9, thus depressing the right hand end of said Vlever and raising the left hand end against the tension of the spring 91. This will lift the screw 81 out of' engagement with the stem of the valve 163 and the latter will then be closed by the tension of its own spring 92. rl`he screws 81 and 82 are so adjusted that as the valve 163 closes, the "valve 173 is simultaneously opened by the engagement of the screw 82 with its stem. and this opening of the valve 173 allows the water in 'the shallow space back of the diaphragm 93 to flow through the pipe 80 and relieve the pressure on theback of said diaphragm member. The main gas valve 83 .will then be closed by the spring 79 thus cuttingoif the flow of fuel to the main-burners of the heater. rlhe temperature of the flowing water will then begin to 4fall and the liquid in the thermostat member will contract, thus lifting the head of tht` box 88 out of engagement with the upper end of the bar 89 and allowing'the ther- ,.mostat lever S3 to be moved back to the position shown in the ligure bythe tension of the springl 91. In this return movement the valve '17 closed by the tension of its spri'ra` 93 and the valve 163 simultaneously opened. thus again exposing the back of the ioci and 17 and will continue under the contrlling action of the thermostat mechanism as long as wa"er continues to flow through the heat-er and varies in temperature below and above the predetermined point of thermostatic cut-olf, said point being varied as desired by the adjustment of the screws 81 and i 82. But as soon a's water ceases to flowl through the apparatus, the valve 343 will return to its seat and the valve 323 will simultaneously be closed by the pressure of the spring 994 thus cutting onv communication between the Water main and the pipe 76. if at this time the main gas valve 83 is open, it W. remain open until the rise in temperature in the water in the aparatus @which can new circulate ilreely through l the thermostat chamber and the port 363 between the inlet and outlet oil the heater coilsmrlses to the point oi thermostatic cutod.) whereupon the valve 1i'Z `will be opened,

.discharging the water back ot the diaphragm 93 and allowing the main gas valve Wette Bil*- 'pressure in the 83: .to close. As all further supply of Water to the pipe i6 and chamber 77 is now cut off, the main gas valve Will remain closed until afiresh supply of water is admitted to 'this pipe and chamber by the opening'oi the valve 323 consequent upon a restabhshment :off a ilovv of liquid through the apparatus.

',:1 Since the pressure ci the liquid in the iwater main. is alvvays very much greater than the pressure of gas, the diaphragm member 93 may be made very small, and the volume of the spa-ce baci; of this diaphragm l'not be in most more than oneylhe volume oi Water tenth of a cubic inch.

.discharged each time that the main gas 'valve 83 is closed is therefore insignificant in. @comparison with the total volume of which collects in the drip pan ot the heater. ASince the number of opening 'and closing movements of the main gas valve under the action of the thermostatic controlis as a matter ot fact 'very small in the ordinary use of heaters'of this type, the Water escaping through 'the pipe 80 could be allowed to flow out directly on the cellar licor if it were not for merely sentimental considerations;

water main is very high, l may place a pressure regulator indicated @fi-in the lpipe so to prevent an ing my invention, in which the main gas valve is actuated in its movement icy electro-magnets, the excitation of which is cen.-

trolled jointly by the position oi the wateractuated member and the thermostatically actuated member. The erJ i, g f' uit Which serves to enel-glee electro-mag nets and thereby ellect the movement eff the p main gas vahve is derived Jrom any suitable me elect'rlcbattery operated by source of electric power external lto the apparatus itsell, "er it may, will pres ently e elained, he generated by then vaste ln. some eases vmere the l illustrate the construcrtion of other control mechanisms, embodyheat of the escaping liue gases. The parts oil the mechanism are so arranged. that current is used only'wliile rthe main gas valve is actually making its opening or closing movements, so that the amount of electric energy used is in all cases very small, and] can be readily supplied either by the ordi! nary bell battery (preferably of thedry cell type) or by a relatively small and comparatively inenpcnsive thermo-electric battery. j

Referring first to the-construction shown in Fig. .7 (which is drawn to a considerably larger scale than the preceding figures), 1f indicates the cold Water pipe leading from the main to the chamber 2,Ax in which the Water-actuated valve 34* is located. A pipe 100 extends from the space above this puppet valve to the cold Water inlet of the top coil (not shovvn ,in this ligure). The Water after passing throughv the heater coils emerges as before from the hot Water outlet 114; enters the lower end of the thermostat chamber 6*, liows upwardly therethrough and out at the top through a pipe (not shown in this ligure) leading tothe desired point of discharge. The fuel supplyenters the main gas valve casing G4 through the pipe F4 and is led'away through the pipe H4 Which communicates with the main burners of the heater. As in previous'c'ases the main gas inlet pipe Fs is provided With a shut-oill cock and a pilot lightgconnection on the inlet sidethereof. 84 is the main gas valve Which is mounted on a long stem 101 that passesthrough the front cap 102 of the gas valve casing 'Grt This cap is of iron and serves as the yoke oi a pair of electric magnets 103 and 104. The outer end of the stem 101 takes a bearing in a second iron plate 105 which serves as the yoke of a pair et electro-magnets 106 and 107. rlhe cores of these tour electro-magnets'are provided at their inner ends-opposite the yokes 102 and 105%vvith conical pole pieces, and between. these pole pieces is a soft iron armaq ture 106 which is adjustably mounted, as shown, on a long collar 109 secured to the stem 101. Ehe thermostat chamber 64. contains a thermostat of the usual composite construction, similar to that shown in Fig. Ll and this thermostat, since it is; not' required to directly move the main gas valve, may bent very light construction, and Will therefore be very readily influenced by small' changes in temperature. The lowerknife edge of the inner negative member 554 of this thermostat engages with the upper imite edge gro-ove of anv obliquely angled thermostat lever 834 exactly the same gin form as that illustrated in Fig. 6 and already fully described in connection thereivi: The supporting knife edge of this r mounted on a hard rub- 110, and the terminal ad `v`and 112 that are also mounted on the insulating block 110, and are prevented from rising above the positions shown in the figure by stops 113 and 114 engaging with their outer ends. The thermostat lever 834 is held in o crative engagement Y.with the terminal kni e edge of the member 554 by means of a compression spring 115, the

upper end of which bears upon, and is in electrical engagement with the leftl `hand end of the lever 834, and the lower end of which is supported in a tube 116 of hard rubber or indurated liber. Mounted loosely on the stem 101 are two collars 117 and 118 of hard rubberior fiber, and on these collars are .mounted contact rings 119 and 120; the ring 119 being adapted to close the-electrical circuit between the terminal 121 of the magnet 106 and the corresponding adjacent terminal 121 of the magnet V107; while the ring 120 is correspondingly adapted to close'the circuit between the terminal 122 of the magnet 103 and the adjacent lower terminal 122 of the magnet, 104. Weak springs 123 and 124 are interposed between the collars 117 and 118 and the adjacent opposing faces of the yokes 102 and 105, and serve to lieep said collars and the Contact rings thereon normally in their circuit closing positions. 125 .indicates a battery-or other suitable source of current, from one terminal of which a 'connection 120 is led to the lower end of the spring 115, and through said spring to the insulated thermostat lever 834. The other battery terminal is provided with two connections. One of these, 127, leads directly to one ter minal of the magnet 104. The' other connection 128 leads to a pivoted arm 1 29 which is weighted at its outer end and is connected at tha-t point to a thin wire stem 334 that passes upward through a stuling box in the lower side of the chamber 24 and is secured at its upper end to the puppet valve member 344. The arm 129 is mounted on an insulating block secured tothe hard rubber head of the magnet 107, and carries a terminal 130 which, when the' arm 129 is raised, makes contact with the lower terminal of the magnet 107. The upper terminals of the magnets 103 and 10G are'connected respectively to the spring Contact arms 112 and 111'.

-or otherwise-can bring about any change in the position of the eleotro-rnagnetically voperated parts of the mechanism, nor close the circuit through the magnets; because under the above conditions the circuit through the magnet coils y106 and 107 is4 interruptedat the terminal point 130, while the circuit through tne magnets 103 and 10.11.v

is broken at the contact ring 120.- Butias soon as a flow of water' is started through the apparatus by opening some tap or bib in the discharge pipe for the house supply,

the pressure on the top of the puppet valve 'y 344, 1s reduced and this valve is raised by the water flowing in through the pipe 14. The raising of this valve lifts the lever 129 and brings the terminal 130 into `engagement with the lower contact block of the magn the battery 125 through the connection 126, the spring 115, the contact screw 814, the spring terminal 111, the magnet coil 108, the Contact ring 119, the magnet coil 107, the lever 129, and the return battery connection 128. rlhis energizes the left hand. pair of electric' magnets and draws the arma ture 108 in the corresponding direction, thus opening the main gas valve 84 and, allowing a supply of fuel to pass through the gas outlet pipe 1 to the main burners of the heater where it is i ited by the iame of the pilot light provided for that purpose. As the armature 108 is moved to the leftcarrying with it the sleeve 109,-the left hand end of said sleeve strikes the collar 117 and moves the contact ring 119 out of et 107. Current now Hows from.k

engagement with vthe adjacent terminal of y the magnets 106 and 107 and breaks the electric circuit through the coils of said magnets just before the armature 108 reaches its extreme left hand limit of movement.

This movement is determined by the en-V gagement of the coned leather washer 614- f similar tothe corresponding washer used in the construction of Fig. t--with the oorrespondingly coned recess about the stem opening in the cap or yoke 102; and this engagement also serves to seal the opening around the stem 101'against any 'leakage of gas and eliminate the necessity for usingx a stuing box for preventing suchleakage.

The parts of the control mechanism will remain in the position just described-with the main gas valve open-until the temperature of the water in the thermostat cha-m-V ber 64 has risen to the point of thermostatic cut-off, which can be varied by the adjustthe spring clip 112 and lift the screw 8P out of contact with the spring clip 111. nThe circuit non' Kiowa from the battery 125 through the connection 126, the spring 115, the thermostat lever 834, the-terminal screw 824, the spring arm 112, the coil of the magnet 103, the contact ring 120,- (this con' vtact ring having .now been brougl't in engagement withv the adjacent magnet terminals by the left hand movement of the sleeve 109) the coil of the magnetl 104, and the rturn battery connection 127. This energizes the right hand set of electromagnets and pulls the armature 108 to the right, thus closing the main gas valve Stand shutting of the flow of fuel to the main heat ing burners. Just before the armature 108 reaches the limit of its right hand movement, the end of the sleeve 109 4engages with the collar 118 and, carries it, and the contact ring 120 thereon, o`ut of engagement with the adjacent contact terminals of the magnets 103 and'104c, thus breaking the circuit through said magnets. 'Both the support of the washer '614 and the main gas valve 8'1 are so adjusted on the stem 101 that the movements of the'armature 108 to i, the left and to the right are arrested. be-

" serted in the heads of Ithe ina its seat bothby the friction of the stem 101 in its bearings, andv also by the residual vfore said armature can come in contactswith the poles of the left and right hand sets of magnets; and to further guard against such contact, brass stops may-if desired-be inl et coils. When closed, the gas valve is he d 'against magnetism in the cores ofthe right hand set of electro-magnets 103' and 104, and if necessary, a weak-compression spring 131-whose tension is justysuliicient to balance the gas pressure on. the right hand side If the flow .of waterv continuesuntil the temperature of, the liquid ,inf the thermoetat' chamber has beenV reduced below lthe point of thermosta'ticv cut-off, the 'contraction ofthe thermostat element will depress the libftflaand end of the thermostat lever 834, and bring the terminal 814i once more in engagement with the contact spring 111. This allows the current from the battery 125 to again flow through the magnets 106 and 107, as already described and the resultant excitation of these vmagnets moves the armature 108to the left again opening the gas valve 84 and admitting a fresh supply of;A fuel to the main burners. These succesl siv opening and closing movements of the valve 84 will continue as long as water continues to iiow through the thermostat Achamberand to successively fall below and rise abovethe temperature at which the thermostat mechanism is adjusted to close the contacts at 814 and'824.

But when the flow of A water is shut. off, the pressures onfthe two A. current through the left vhand set of magnetcoils. If, at the time the water is shut olf, the gas valve is closed, it will'remain closed until the flow of water is once more Astarted through the heater. If the gas valve is open when the flow of water is stopped, it 75 will remain open only long enough to allow the water in the thermostat chamber to be raisedv tov the point of thermostatic cut-off, and will then be shut by the closing of the contact at 824 and the resultant excitation so of the right hand set of magnets 103 and 104. This will bring the partsinto/the position shown in the igure, in whichposition, as already explained, no further current can flow through either set of magnet coils, until the terminal 130 has once more been closed by the lifting of the valve 34.

. The construction illustrated in Fig. 8 is of l the same general character as that illustrated in Fig. 7, but differs from the latter in some mechanical details. In this'apparatus only a single set of magnet coils is used to produce thf double openin and closing movements of the gas valve. nly one of the. coils 132 5f this set is shown, this -coil being located just plane, the cores of the two coils being joined S160K b the yoke 133. The gas valve 8s is pivotally mounted in the forked end of a lever 134 that is mounted on an axis 134 and carries at its lower end an armature, 135 which swings in close proxlmity to the poles of the connected electro-magnets. One fork of the arms ofthe lever 134 is extended upward at one side of the valve 8'i to carrym. contact brush 136 that engageswiththe'insulated commutator segments `137 and 13,8. In this 11.0 construction the water from the main passes directly `into the cold water inlet of the heater (not shown in the drawing) and after flowing through the heater ,cos, emerges from the outlet 45, enters the 'side of the 115 I use inthis construction isA of the liquid 12g` type, and consists of a corrugated box4 -141 which is hermetically closed at bothpends and is filled with a suitable expansion me- 1 dium. I prefer to employ for this purpose some relatively dense and more or" less viscous liquid like petroleum oil or olive oil or some material. like paraiin or an eutectic alloy such as VVoods metaLwhich is"v solid at low temperatures, but which becomes liqj u id at temperatures less than that for vWhich 139 p the thermostat is designed to actuate the 141 is recessed to engage the upper end of a short stem 142 which passes down through a stuffing boX in the bottom head of the thermostat chamber 65, and engages at its lower end with the short arm of a bell crank thermostat lever 143. The long arm of this lever is provided with a contact pin 144 mounted on an insulating block 145. Adjacent to the two ends of the contact pin 144 I arrange 'two contact terminals 146 and 147, both mounted on an insulating block of hard rubber. or fiber secured to the right hand wall of the gas valve casing G5 The puppet valvc140 which is arranged in the outlet passage from the thermostat chamber, is provided with a stem 335 which passes downward through a stufling box in the lower wall of the chamber 139, and bears at its lower end on a spring contact arm 148. The valve 140 is normally held in the position shown in the figure-in which the contact arm 148 is moved away from the contact block 149-by a compression spring 150. From one pole of the battery 1255 a connection 151 is led to a terminal of the set of elctro-magnetic coils, and from the other terminal of said coils-which are arranged in series with each other-a second connection 152 is led throughthe lever .134 to the insulated brush 136. The two commutator segments .138 and 137 are connected respectively to the terminal 147 and the contact arm 148; and from the contact block 149, another connection 153 leads to the terminal 146. The other pole of the battery is connected by a wire 154 to the contact pin 144 in the end of the thermostat lever 143. The latter is normally held in the position shown in the figurein which the contact 144 is in engagement with the terminal 146-'by means of a compression spring 155 engaging with the lateral projection on thelcver 143. fr

';;The operation of this mechanism is inI general the same as that of Fig. 7. It will therefore be readily understood with a very brief description. When no water is flowing through the apparatus, the valve 140 will be held closed by 'the spring 150 and the contact arm 142 'will be out of engagement with the terminal 149. If the temper'- ature of the water in the thermostat chamber. 65 is at such time below the point of predetermined cut-off (as it will Aalways be 'after the completionof the last cycle of control operations) the thermostat member will be out of engagement with thestem 142 and the lever 143 will be held in position shown in the ligure by the spring 155. In this position of the parts no current can pass through the magnet coils until a How of 'water has been started through the apparatus by opening some pointof outlet in the discharge pipe 75. When this is done, the valve 140 will be lifted from its seat to allow the water to iow from the heater to the point o f outlet, and this lifting of the valve and its connected stem 335 will allow the terminal of the spring contact ,arm 148 to come into engagement with the block 149. This will close the circuit through the magnet coils, the current now flowing from one pole of the battery 1255 to the contact 145 thence through the connection 153 and contact 149 to the contact arm 148, thence to the commutator segment 137 and brush 136 bearingv thereon, thence through the connection 152to the magnet ycoils in series and from the latter to the battery through the return wire 151, The resultant excita- -iinn of the electro-magnets attracts the armature 135 and swings the arm 134 to the right, thus lifting the main gas valve away from its seat. As this arm passes the vertical, the circuit through the magnet coils is broken by the passage of the brush 136 from the commutator segment 137, butV y the arm continues to swing to the left under the inertia of its initial movement until it Y assumes the position indicated by the dotted lines in the figure. The opening of the l gas valve allows fuel to flow from the gas inlet pipe Ft to the gas outlet pipe H5 and thence on to the main burners of the heater where it is of course ignitedby the usual.

pilot light, The heat of the mainy burners'k immediately begins to raise the temperature of the flowing Water, and this in turn eX- pands the material in the thermostat box 141 and depresses the stem 142 thereby moving the thermostat lever 143 to the right against the pressure of the spring 155, andA ultimately bringing the contact 144 into engagement with the adjustable terminal 147. `When this occurs, the circuit is again closed through the magnet coils by the-passage of the current from the contact 144 to attracts the armature 135 toward the poles'V of the ma net system, and this moves the arm 134 rom the dotted position back to the full line position. As this arm passes the vertical, the current is once more broken through the magnet coils the brush 136 leaving the commutator 138, but as before the arm continues its 4motion until the main gas valve 85 has reached its seat and cut off the flow of fuel through the gas valve chamber. The weight of the gas valve is sufficient to hold the latter firmly against its seat against the slight-pressure o'fthe gas in the inlet pipe, and the valve will remain closedtuntil the ltemperature of the ufl flowing .Water has lfallen sufiiciently to withdraw Athe stem 142 from engagement Withthe'thermostat lever 143 and allow the once more closed through the magnet coils -y sition of'the lower head of the thermostat v20.

in themanner already described and the gas As long as water continues to flow, theseopening and closing movementswill occur in regular su ccessionas the circuit through the magnet coilis established by successive contacts of the pin-144with the terminals 146 and 147 the temperatures at-which these movements occur being varied at will by the joint ad- `justment of the contact screw 147 and the screw 156, which latter screw varies the pomember by varying the volume of space within the thermostat boic. But when waterceases to flow, the valve 140 lis re-v turned to its "seat by the pressure' of the spring 150, and the resultant downward movement of the stem 355 moves the terminal of the arm'148 out of engagement with the block 149 thereby preventing any fur ther How of current through the magnet coils when the main gas valve is vin its closed position.- If the iow of water is shutotf 'while the main gas valve is open, it'will remain open only long enough to allow the temperature of the water in the heater or the thermostat chamber vto be `raised to the point of predeterminedV cutoff. When this point is reached, the main gas valve will be closed, in the manner already described, and will remain closed fromv that time on until the How of .water has been' restablished and the valve member 140 again raised.

In -Fig. 8'I illustrate a means for recharging the`battery'1255 each time thatthe apparatus Iis put into service. The means there shown 'comprises a thermo-electric battery 157 which is placed at any convenient lplace in the chimney or :flue leading from the heating chamber'and is provided With connections 158 and 159 which lead from the terminals of said battery to the terminals of the battery .1255. 4"When the one set of terminals'of the battery 157 is exposed to the hot gases escaping from the heating chamber, current is generated which re-charges thebattery 1255, the lconstruction of'thefbattery 1 57 being of course such that the voltage of the thermofelectric current thus produced, is onthe average slightly in excess .of the voltage of the battery 1255.

In order to avoid any flow ofv current from the battery 1255 through the charging battery 157, when the heat is shut 0H, oneof the connections, as 158, is led through av switch contact 160 which is closed onlywhen the water is flowing, and when consequently het gasesfa're escaping vfrom the heating chamber. Other automatic means controlled"l by the operation of either the'Water-actu-- ated member or the .thermostatically-actuated member,.may of course be employed for" the recharging of the battery 125 each time that the heating apparatus is putin service.-

It will be readily apparent to any one skilled in the art that the' various imechanismspreviously described may be equally well used for the control offthe fuel supply to the burners of a storage tank heater. It will also now be readily apparent that various detail modifications of these mecha- .nismsinvolving nothingmore than the ex'-A d ercise of ordinary mechanical skill--inay be readily made to adapt them for use on other specific forms o1 heating apparatus than those herein shown and described.V

`Having thus described my invention and illustrated its use, what I claim as new and desire to secure by Letters 4Patent is the folil lowingt I -1. In an automatic water heater, a burner,

' a gas valve for" controlling the supply oi gas to the burner, a member actuated by the dif'- .ferences of Water pressure caused by opening and closing the outlet from the heater, `a g thermostatic means operated by theheater water, means actuated by fluid pressure' for,

operating the gas valve, and two valves for controlling the application of the fluid presranged infseries in the linel of flow of such fluid pressure, one of such valves being oper-l ated by the water-actuated member and the otherof such valves being operated. by the;

thermostatie means.

'water, means actuated by :tluid pressure for operating the gas valve, and two'valves for controlling the application of the Huid pres sure to the power controlled means arranged in series-in the line of ow of .such Huid pressure, one of such valves bemg operated vsure to the power controlled means arbythe Wateractuated membervand the other 'r Y of suchvalves being operated by the thermostatic means, and the first of said two valves being arranged to cut 0E the application of the fluid pressure when theoutlet from the heater is closedfand the second of such valves being arranged to permit the application of the fluid pressure when: the

heater water is below a predetermined -temd perature for which the thermostatic'means i is set, and the first valve is open.

f B. In an automatic water.- heater, aburner, a gas valve for controlling thesupplyfof gas to the burner, a member actuated by the f differences of water pressure vcaused 'byopening and closing the outlet from the heater, a thermostatic means operated by heater Water, means actuated by Huid sure for operating the gas valve, and ta/io Valvef-nr controlling the application of the Huid pressure to the power controlled means arranged in series in the line of How of auch Huid pressure, one of such valves being moved to open position through the movement of the wateactuated member when the outlet from the heater is opened, and the other of such faires being heid in open po- `sition when the heater Water is below a, predetermined temperature and moved to dosed position by the thermostatio means when, the heater water reaches a temperature above such predetern'iined temperature.

in an automatic y'ater heater, a ioni-oer, a gas valve for controlling the suppiy ot-gas to the burner, a memberf actuated by the `ditferences of water pressure caused by opening and closing the outlet from the heater, a thermostatio means operated by the heater Water, an abutment actuated by iuid pressure for operating the gas valve, two valves tor controlling the application ot "ici-pre."- siue to the said abutment arranged m,

' in the line of flow of such fluid vreesure one of Such vaives being operated by 'the waterpower to th` actuated valves being e n eens, 'the therm ot ment a ated vaie i 5. in an f a gas Yaive for ooohto the bmxa water.,

power tor more the two means auch actuated being oe