Dec. 31, 1946. A, R, DRAFFlN ELECTRIC WATER HEATER OF THE STORAGE TYPE Filed Dec. 2S, 1944 /4 /00 2,413,6Èl Patented Dec. 31, 1946 2,4l3,5ll UNITED STATES PATENT OFFICE ELECTRIC WATER HEATER OF THE STORAGE TYPE ' I Arthur Robert lDraíi‘in, Camberweìl, Melbourne, Victoria, Australia Application December 26, 1944, Serial No. 569,840 In Australia December 13`, 1943 11 Claims. (Cl. 219-39) 1 2 This invention relates to electric water heaters of the storage type, designed to provide for a substantially continuous supply of hot water for domestic and other purposes and more especially to such installations which operate upon electric current supplied on an oiî peak or restricted hour tariff (sometimes known as night heating) and under a higher or ordinary domestic, comercial or industrial tariiî (sometimes known as day switched orf, the diiîerence in temperature is most noticeable and low temperature water is likely to be drawn off ata comparatively early stage. In cases where a thermostat device is ñt ted, it is located near the bottom of the storage Vessel but such device is of-no practical use when ers may be said to fall into two main classes, i. e. operating upon the ordinary tariff unless it is desired that the entire body of water should be heated. Tyre B-_According to this type an electric heating element is immersed in the water near the bottom of the storage vessel and heats the entire body o1" water during the off-peak or re those `which operate upon the “displacement” or stricted hour period. - Notwithstanding the use of “pressure” principle according to which cold water is fed into the bottom of the storage a throw-over switch for replenishment when operating upon the ordinary tariii, a long delay chamber and hot water is taken oil from the occurs before hot water at a desirable temper heating). So far as concerns the manner of generating and delivering the hot Water, such storage heat top, and those which operate upon the “falling level” or “spill over” principle according to ature is available for drawing off. This delay is due to the fact that the element has to transmit which the hot water is delivered o1' drawn olic 20 its heat into the main body of water and thus, from near the bottom of the storage vessel. all of the water has to be heated before any hot I consider that the displacement or pressure water can be drawn on”. Similarly to type A, type principle is to be preferred for various reasons, B is frequently fitted with a thermostat device primarily in that it provides a better operating near the bottom of the vessel, but this device efficiency, which is of paramount importance. In 25 switches off the current only when the whole of addition, there is the physical advantage that the storage vessel has been heated. the storage vessel of a “displacement or pressure” Type C.-According to this type, two separate type heater may be installed in practically any heating elements are employed, one -being im position such as under the floor, on the floor, mersed in the water at or near the botto-m of the in a cupboard, or in the roof of a building, vessel and the other element, usually known as Whereas‘wíth the falling level type of heater, the an upper or booster element, is arranged within storage vessel requires to be elevated above the the vessel near the top thereof and is intended highest draw onq point or tap of the system. to replenish the supply of hot water at the upper There are numerous types of heaters which operate upon the aforesaid “displacement or part of the vessel to meet an urgent demand. If the quantity of water above the upper or booster pressure” principle. The salient features of the element amounts to say l0 gallons then, while four main types of such heaters will now be briefly described as `such description. will >assist a better _understanding of the present invention and the important advances which arise there from. Type A.-According to this type a circulation the installation represents an improvement upon electric heater is arranged externally of the stor age vessel and progressively heats all oi the water in the latter by a circulation of the water from the bottom of the vessel through the heater and into the top of the vessel. Satisfactory results are obtainable when operating upon a continuous heating tariiî but it is found when operating dur ing the oli-peak or restricted hour period there ‘ is a very great difference in temperature between the hot _water at the top of the vessel and the `water at-the bottom or the vessel, at the end ol the heating period. Thus when hot water is being drawn oil and the electric current is f types A and B, it suffers from the disability that it does not make sufficiently hot water available for drawing off until substantially the whole 1D gallons of water has been heated throughout. In this type, a thermostat device is ñtted near the bottom of the storage vessel to control the heat during the oil-peak or restricted hour period, but the upper or booster element is either switched on or oli by hand, or if it is desired to be rendered automatic in operation, then an ad ditional thermostat has-to be ñtted. Type D..--In this case a heating element is im mersed near the bottom -of the vessel and is so arranged that a proportion of the heat is trans mitted. into the main body of water, while the re mainder of the heat is transmitted to a confined body of water which passes by way 'of an external tube to the top of the vessel. The heating ele 2,413,611 3 4 ment, when operating under the restricted hour tariii heats the whole of the water in the storage clusion of the heating period. When the supplt7 scribed with reference to one practical embodi ment illustrated in the accompanying drawing in Which Figure 1 is a vertical elevation, partly in sec tion. of hot water approaches exhaustion during day time use, replenishment of hot water is effected Figure 2 is an enlarged sectional elevation of the hot-water control valve or diverter device and vessel although there is a slight temperature var iance between the top and the bottom at the con associated parts. by operating a throw-over switch whereupon the An installation in accordance with the inven electric current is charged for at the ordinary tariff. A proportion o-f the heated water is de 10 tion includes a cylinder or vessel 2 of appropriate capacity to serve as a hot water reservoir. This livered to the top of the storage vessel readyV for vessel is surrounded by a lagging 3 of appropriate drawing oir, but a considerable proportion ofj the heat insulation material and has a cold water heat is still transmitted direct tc the main body inlet ll at its bottom connected with an overhead of water. Thus, while this type represents an im provement over the previously mentioned types, it 15 cold water supply tank (not shown) which, as usual, may be fitted with a ball-cock device or the still does not replenish hot water at the top of the like. ` vessel with suiiicient rapidity. It is customary A single electric heating element 6 of the water circulating type is located in any suitable posi rent when the entire body of water has been raised 20 tion preferably immediately beneath the bottom of the sto-rage vessel. The heating element casing to a given temperature. This is'eiiective for the 'I is surrounded by a jacket 8 one end of which is ofi-peak or restricted hour tariff heating but if connected by a pipe 8a with the bottom of the the current is carelessly'or otherwise left switched storage vessel near the point where the cold feed on after replenishing the supply of hot water dur to provide a. thermostat device near the bottom of the vessel for automatically switching cif the cur 25 water enters the vessel. A baiile (not shown) may be provided within the lower part of the vessel to mostat will not switch off the current until the prevent the incoming feed water from mixing withentire body of water has been heated to the pre the hot water in the upper part of the vessel. determined temperature notwithstanding that The heater water jacket 8 should be inclined only a relatively small amount of hot water may be required for immediate use. This is, of course, 30 slightly towards its other or outlet end from which a pipe or conduit 9 extends upwardly and may wasteful and uneconomic. be said to have three branches. One branch I0 The present invention aims to overcome the leads horizontally into the storage vessel at a rela foregoing disadvantages and disabilities in a sim tively slight distance above the bottom thereof. A ple and practical manner and to provide for the utmost efficiency, convenience, reliability and 35 second branch II continues vertically upwards and enters the top of the storage vessel preferably economy in the operation of storage heaters of adjacent the hot water outlet 2a which may have the kind in question. the usual exhaust pipe (not shown) associated ' More speciiically the invention, while employ therewith. The third branch I2 extends hori ing only a single heating element and a single thermostat control device, provides for the entire 40 zontally outwards in alignment with the iirst branch and is connected to the water control valve body of water to be heated to an even tempera or diverter device I3 as best seen in Figure 2. ture throughout, which is ideal especially when These three pipes or branches should extend operating on the off-peak or restricted hour tariff, through the heat insulating material 3 around the and also provides, as and when required, for the most rapid replenishment of hot water at the top 45 storage vessel so as to avoid dissipation of heat. As illustrated, Áthe device I3 comprises a rela of the storage'vessel so that it becomes readily tively small capacity water chamber I4 into the available to meet a sudden demand or emergency. upper part of which the third mentioned branch In order to accomplish this and certain other I2, or a tail piece I2a connected thereto, opens. desirable _objects as' will be explained more fully hereinafter, I employ a single heating element of 50 Around the exterior of the lower part of this water chamber there is clamped a relatively low the water circulating type and connect it with a hot water storage vessel and in a water ñow cir wattage electric hea-ting coil I5, suitably insu cuit which includes a hot water control valve or lated, and which may be adapted to be energised diverter device.V In one condition this device di only when the installation is operating under the rects the heated water from the circulatory heater 55 ordinary tariff. In such cases this heating coil ingoperation upon the ordinary tariiî, the ther into the lower part of the storage vessel so that the may be operatively connected with a throw-over entire body of water is gradually brought to a de sired temperature, and, in another condition, di Retained within the lower part of the chamber verts all of the heated water from the heater di I4 is an expansible bellows I8 containing~ a suit rectly into the top part of the vessel, so that hot 60 able quantity of an appropriate substance'which water is almost instantaneously or, at least, very has a high rate of expansion when subjected to quickly available at any draw oiî tap of the sys heat. Upstanding from the head or top of these tem, notwithstanding that the major portion of bellows is a rod I'I connected by a pivoted bell the water in the vessel is cool or well below a de crank lever I8 with a horizontal rod I9 extending sirable high temperature. 65 from a plunger Zülwhich is disposed in the third switch. The water control valve o-r diverter device is preferably arranged to be brought into action au tomatically upon switching over to operation upon the ordinary tariiî, while a single .thermostat de viceis arranged to exercise control over the heat ing element at all times, i. e. whether it is op erating under the oir-peak (night-time) tariii’ or A ’ ' ` branch I2 and has a tapered or conical nose 2| adapted to make contact with a correspondingly shaped seating 22 in the first branch I0. 'A spring 23 may be associated with the before-mentioned parts in order to yieldingly oppose' expansion of the bellows device and to retract the plunger 20' from the seating 22 of branch Ill. 'I'he plunger ordinary (day-time) tariiî. should be .a good sliding ñt within kthe third VThe above and various other objects, features branch but it is preferably tapered away as atï 24 and advantages of the invention will now be de 75 and has an end portion or `tail piece 24a of nor 2,413,611 E 6 mal: diameter .at the rear of the tapered part 24. the upper part. of the- storage vessel. . Only one thermostat control device is required interval of time the thermostat. will again switch onthe'current where the water surrounding it has `dropped appreciably in temperature. This according to this invention, and such device, which ‘may be: of any suitable form. and suitably connected in the electric circuit, is ,preferably After an automatic. switching on and off action will be located within a tube 25 closedv at its inner end repeated until eventually all the water is heated. It will be. apparent from the foregoing that the invention> permits of full advantage being taken When‘the installation is in use under the. oir of botlr off-peak and normal. tariffs and, -by virtue peak tariff the`v plunger 20 will, by reason of the of the hot water control valve or diverter, enables spring` 23 and the collapsed condition of. the hotl water to be obtained at any time at any draw bellows ITS, be withdrawn from the seating 22 in oiî pointin .the system without wastage of electric branch- pipe Ill' as seen in unbroken lines in Fig current, in a; most economical way in that such ure'f2. Thus; hot water fromvthe. heating~ element hotl water is delivered. directly from the heating jacket will flow through branchv I0 into the lower 15 element jacket into the top of the storage vessel. portion of’ the. storage vessel so that the entire In addition to the ability to quickly replenish body of water therein will> be gradually brought the supply of hot water at ordinary tariff, the di' up to a substantially uniform temperature. When verter device also enables, if it is so desired a this has been eiïe‘cted to the required tempera portion only of the water to be heated at the off ture, the supply of electric current to the heating 20 peak or restricted hour tariil”. This is eiîected element will be automatically cut-off. by the by moving the usual throw-over switch to the oiî thermostat device. y peak position and switching the low wattage heat If and when the supply of hot water in the ing coil I5 into circuit. Thereupon the water in storage vessel has become exhausted or is :ap the upper part of the storage vessel will be heated proaching exhaustion and hot water is urgently and as soon as it has reached the desired tem required at `any draw-01T point in the system., as perature- the thermostat will automatically cause may frequently happen in day-time, then the the current to the heating element to be initially low Wattage heating coil is brought into action. switched off. ~ ^ The heat produced by this coil rapidly heats the It will be noted that a small diameter pipe 26 water in the chamber I4 and when such water leads from pipe 9 into the water chamber I4 and reaches a suitable~ `temperature the bellows de' that another small diameter pipe 21 leads from vice I6 expands, and, through medium of the the rear part of pipe I2 upwardly into pipe II. aforesaid rods and lever, moves the plunger 20 The primary purpose of the pipes 26, 21 is to pre along the third. branch I2v so that the cone or vent steam accumulation and overheating ofthe like, Shaped nose 2| of the plunger contacts with ' water in chamber I4 when the coil I5 is switched the seating 22 at the inner end of branch I0, as on, Under such condition, and with the plunger indicated by broken lines in Figure 2. As a result, 'moved onto its seating, the two pipes provide for the hot water from the heating element cannot a small by-pass or circulatory iiow of hot water now enter the water storage vessel through from pipe 9, through pipe 26 the chamber I4 and branch I0 but passes around the tapered portion 40 pipe 21, into pipe II. The tail piece 24a of the 23 of .the plunger and travels upwardly through plunger will, at this stage, be located between pipe the second branch Il into the top of the storage 21 and branch I I as indicated by broken lines in vessel so that the heated water is practically in Figure 2. stantlyv available for drawing. on. Until the tail piece 24a moves to the right past andv projecting horizontally into the vessel at a relatively short `distance from the top. By tapering the plunger as- aforesaid and ar» , ranging for such tapered portion to come adja centjthe upper end of pipe 9, there is a desirable restriction in the pathway for the hot water which ensures it reaching the top of the vessel at the desired temperature. There are several advantages in. adopting such method of restric~ tion, in relation to the usual method of- requiring thewater in chamber and a quick movement of the plunger against seating 22. Y the Water to pass through a small ñxed oriñce or hole. Thus, there is no likelihoodv of Athe re~ stricted pathway becoming blocked by foreign , matter in the water, and any' matter that may be deposited `around the pathway will be re moved by the movement of the plunger. When the throw-over switch is returned to the off-peak position, the low wattage heat coil is simultaneously switched oiT so that the water in' cham-ber I4 will cool and .the `pressure of the contained chemical or other substance in the bel lows will be reduced so that the associated spring 23 will force the bellows back to normal and at the same time cause the plunger to be withdrawn Vfrom the seating at the inner end of the branch I0 .whereby direct communication is re-estabw lished between the heating elementaiacket and the-lower part of the storage vessel. " pipe' 21 as aforesaid there will not be any circu lation of hot water through chamber I4 and this is an advantage as it will lead to quick heating of ' ' If thethrow-over switch is left on' in the normal ,tariiï position, then the current supply tothe heating element will be automatically switched kof! -by the thermostat device aftera predeter mined quantity of hot water has accumulated in 75 It is to be understood that the construction of the hot water control or diverter device I3 may be varied in many respects. For instance, the heating coil I5 could be replaced by a solenoid a‘p propriately connected in the electric circuit and arranged to actuate the plunger 20 or other suit able valve through suitable linkage, upon opera tion of the change over switch. Alternatively, a plunger or other suitable valve could be adopted for manual operation. Having now described my invention what I claim as new and desire to secure by Letters Pat ent is: l. In a water heater of the storage type suit able for operation under the off-peak and the or dinary tariffs of electric supply, a hot water stor age vessel, a heating element of the water circu lating type having a water inlet connected with the lower part of said vessel, a thermostat con~ trol. device for said heating-element, andra water flow circuit extending between a hot water outlet of said heating element and upper and lower hot water inlets of said vessel, said circuit having in terposed therein the controldevice which, selec tively, directs heated water 4exclusively from the heating element into the lower part of said vessel 2,413,611 8 7 second branches, a Valve member selectively ’oper ableA to- exclusively vcut on" communication be tween‘the iirst branch and the second' branch while maintaining the ñrst branch open to'said pipe, or tor exclusively cut >off communication vesselso as to effect a rapid development of hot between said pipe and the iirst branch while Water for immediate withdrawal. ' 1 . ' Y ' maintaining the pipe in communication with said 2.*In a Water'heater, as claimed inv claim l, second branch by Awayof said third branch, said wherein said water ñow circuit includes a pipe valve 'member including( a plunger having' a extending »upwardly from the hot water outlet of said heating element, a first branch extending i) tapered portion to- 'restrict communication'be tween said pipe leading from the heating element from said pipe into the lower part of the storage and said second> branch when the valveis in“ vessel, a second. branch extending into the top of one selected position, said plunger having a tail the storage vessel, and a third 'branch- .for inter piece of normal'diameter spaced rearwardly from connecting said ñrst and second branches, a valve softhat the .entire body of water- therein.. is gradu ally raised to a desired even temperature through-. out or exclusively directs all of the hot. water from the heating element into the top part of the member being provided and selectively~ operable~ . to.; cut 01T exclusively communication between the ñrst> branch'and the second branchmaintaining the iirst branch open to said pipe, or to- exclusive ly cut off communication between said pipe and the ñrst branch to cause the pipe to communicate ' with said second branch. 1 " « 3. In a water heater, a combination as claimed in claim 1, wherein said control device includes a relatively small capacity water chamber con-i nected in saidflow circuit and heated by a rela tively low wattage coil, a heat expansivebellows in said chamber, a valve for .controlling the ilow of hot water from said heating element exclusive-v ly to the lower part Vor to'th'e top of said'vessel, and operative connection between'said bellows and said valve. ' 4. In a water heater, a combination as claimed said tapered portion. . Y ‘ .¿ . 7. A water heater as claimed in claim 1, wheres inv said hot water control device' is opera-blebto direct hot `water exclusively into the'top ofthe storage vessel automatically upon the operation of a switch for changing over from olif-peak tariii‘ to ordinary tariff. . « 8. A water heater as claimed in claim 1, where in said heating element is located adjacent the bo-ttom of said vessel, and wherein said thermo~ _ stat device is positioned within the upper part of said vessel and is adapted to control the supply of current to the heating element both when hot-water from the heating element is directed to the bottom or to the top of the vessel and irrespective of whether the'apparatus is. op-l erating under the off-peak tariff or the ordinary tariiï. - ' 9. An improved water heater of the storage in claim 1, wherein said control device includes type, including a hot water storage vessel, a a relatively small capacity water chamber con‘ nected in said ilow circuit and~~heated by a re1 3.5. heating element located beneath the vessel and disposedxwithin a casing; a water jacket sur: atively low wattage coil, a heat expansive bellows rounding _said casing, an inlet’pipe 'exten-_ding in said chamber; a valve for controlling the flow froml the lower part oi the vessel into theî one of hot water from said heating element ex end of said‘jacket, a hot water outlet pipe lead-f clusively to the lower part or exclusively toA the top of said Vessel,- and operative connections be 40 ingupwardly' from the other'end of said jacket, a first branch extending from said outlet pipe tween said bellows andA said valve, saidv bellows into the lower part of the vessel, a second branch being retained within said water chamber with extending from said outlet'pipe into the top of its upper free end connected to a rod carrying the storage vessel and a control device .operative said valve'member. . . ' 5. In va water heater, a combination as claimed selectively to place vsaid hot water outlet pipe in claim 1, wherein said water flow circuit in» into exclusive communication _with said _ñrst cludes a pipe extending upwardly from the hot branch or with said second branch as may be Water outlet of' said heating element, a- first branch extending from said pipe into the lower desired. ' - ~ ^ > . _f ' 1 10. An improved Water heater asl claimed in part of the storage vessel, a second branch ex- f” claim 9, wherein a thermostat device isarranged a third branch interconnecting said ñrst and within-and at an appropriate distance beneath the top of said storage vessel and is operatively second branches, a valve member being provided and operative selectively to exclusively cut off control its operation irrespective of theselected communication between ‘the’ ñrst branch and the « positions of saidcontrol device. tending into the top of the .storage vessel, and connected with said heating element so as to Y ~ , 11. In a water heater, a combination as claimed second branch» while maintaining the ñrst branch open to said pipe, or »to exclusively cut »off in claim '1, wherein said controldevice includes a relatively small capacity water chambercon communication between- said pipe and the first nected’in said iiow circuit to be' heatedby a branch and maintain the pipe in communication with said second branch by way of said third i., relatively low wattage coil, a heat expansive bel-_ lows in said chamber,- a valve for controlling the branch, said valve member including a plunger now of hot water from said heating element ex having a tapered portion to restrict communica clusively to the lower part or to the top of said tion .between said pipe Yleading from the heating vessel, an operative connection between said bel element and said second branch when the valve isin one selected position. a ¿ , lows and said valve, and arelatively small d_i¿-_ cludes a .pipe extending upwardly'from Ythe -hot aineter pipe establishing communication between said hot water outlet from the ¿heating element 'and said water> chamber vand another relatively water outlet of said heating` element, _.a ñrst small diameter pipe for-establishing communica .6. In a water heater, a combination as claimed in claim l, wherein said water ñow circuit in-` branch `extending. from said pipe into the lower part of the storage vessel, a secondvbranch ex-l tending into the top of the storage vesseL'and. a. thirdbranch for interconnecting said ñrstv and tion'between said chamber and the >top part of said storage __vessel'when said control device is ' in one selected position. ARTHUR ROBERT -DRAFEiNL '