US1898703A - Water heater - Google Patents

Description

Feb. 21, 1933. D B. W|LL|AMSON 1,898,703

WATIERU'. HEATER File/July 5,0, 1932 2 sheets-sheetA 1 INVENTOR Feb. 21, 1933. D, B. wlLLllAMsoN WATER HEATER Filed July 30, 1932 2 Sheets-Sheet 2 5 lNvENToR MMM Patented Feb. 2l, 1933 PATENT cartes noNatnmwnLIamtsQN. or HTTSBURGH, rnNasYLVemae-sssmm .T0 -raEfPeQI-@S .NATrnALnas G QMBANLA.solares-mortier.PENNSYLYAMA WATER HEATER .natation med July.

n, This invention relates to a water heater of the side arm type. That is to a water heater comprising both a storage tank `and a; heater proper, which latter is in return communication withthe storage tank.

The specific type lofwate'r heater to which the improvements of my invention are applied has a cold water inlet to the tank in the yupper region thereof; a Warm water outlet .Y

from the lower region of the tank4 to the heater coil; and a Vreturn line-from the -ldischarge `end of the heater coil .to :the tank, this return line extendreverse flow to the-discharge end ofthe heat- 25 oit such type a control thermostat for the gas'V ing coil, is prevented. Previously in a heater -lineto the heating coil has beenpositioned ,A an

Vwithinthel tank, and inthe lower region thereof. Y

Thistype .of heater, as deinitely described aboveisv prompt in its action, andis reasonablyetticient. l. It carries, however, an unduly .hightank temperature; and the hottest region ofthe tank` being the upper regionltherein, :there is a substantiallossof heat by radiation. A defect in operation is that a.con.Y siderable quantity :of` cold .water must enter i (the tank beforethe thermostat operates to tothe lower region temperature, operates to cut off gas supplyto the burner.

The primary object offthis vinvention .is to improve a waterheater ofthedescribedtype y by so positioning and associating-.the control Y 5; .Service withdrawal Of Weten and .that 'ifats vthermostat thatu it acts/instantaneously to supplyfgas totheburner of the 4heliating coil upon :the top of l,the tank. A

pipe 3 leads from the .bottom .of the tank ,to a heater proper 4, which lis to, be.understood as i932. `serial v No. vezegieo.

under the inuence of thehighest .tank 4tem- Y .peraturelto cutl offgassupply at timeswhen no' withdrawalis'being made.

.A .furtherfobject of the invention is to` provide means guarding against objectionably .high temperature ofservicewater in1large` capacity installations.

4In the accompanying drawings-Figure. I is an .elevational view, Ashowing a heater` embodying` the primary improvements 'of `my in- .vention Figure II is a fragmentary elevational view, showing a inodifled positioning of. the control,thermostaty-Figure; III is a Vfragmentary elevational v4view .showing the use of athermostat for controlling'the temperature .ofy waterfflowiiig kto service, and

adaptable foraddition toeither structure ilulustrated in Figures I andII, andFigure `IV is a detail view, in vertical section, showing thecheck valvel comprised in the apparatus andthelitting in which itis installed. y

In. the. drawingsreference numeral l desf-ignates the storageitankof the heater, which has acold watersupply pipe@ l,coniiecjtefdf at comprising a heating coil ,.or its equivalent heating element, to the intake end ofgwhich pipel l3 connects. pThe heater. proper also comprises a burner of knownsort, a lportion v ofwhichis shown at 5. @The heaterfllhasthe outletof itsheatingelement connectdto a discharge pipe 6.

l Disjchargapipe dbranches; onehbranch 7 vextending downwardly ,in tanky 1;v to a point adjacent the bottom4v thereof andf theothen or service, .branch` 8l v leading to a Vfaucet or vvsupply gas tothe .burner of the heating coil. Conversely, the temperature in the .upper re- Y .Y gion of the tank reaches the highteinperature noted, before the thermostat,` being regulated bottom ofthe tank byfvv'a'yfotpipe, Gwand 100 warm Water outlet branch 7 At times of service withdrawal circulation is from the bottom of tank 1, through the heater 4, and from the heater, by way of pipe 6 and service branch 7 to service.A All service water is taken directly from the heater.

The gas supply line 10 has therein a pilot burner 11, and thereafter enters heater burner 5 to supply fuel thereto. The automatic gas control means act to control gas flow in the region between pilot burner 11 an-d the main burner 5.

Fuel supply to burner 5 is controlled by a suitable valve 12, operated by thermostat 13. As shown in Figure I of the drawings, thermostat 18 is mounted in a fitting 14 of cold water supply pipe 2, and comprises a bulb extending downwardly into the tank from the top thereof.

It is to be understood that communication.

1 enters the tank in its lower region and moves upwardly through overlying water to the upper region ofthe tank. rThis current tends to produce an equalization in the temperature of tank water, but inevitably during `the continuance of these conditions the upper region of the tank becomes the most `highly heated region. The cycle continues until the water temperature in the upper region of the tank becomes elevated to the point at which thermostat 13 has-beenV set to operate in cutting 0H fuel supply to the burner.

v 45 By exposing the control thermostat to the highest normal tank temperature, the tank temperature is definitely limited for all regions thereof. When a mostat setting has been produced in the upper region of the tank, the thermostat operates to again supply fuel to the heater burner.

Hot water then passing from the heater to the tank does not affect the thermostat until it has risen from a point adjacent the bottom ofthe tank to the upper portion thereof in the region of the thermostat.

A service withdrawal of water from the.

:system instantly causes cold water to enter Y at the top of the tank from supply pipe 2.

This cold water, acting Aon thermostat 13, operates gas valve 12 to suply fuel to burner 5. Substantially all thewater passing to service; from the bottom of tank 1,. and through heater 4, is directly-heated during 6s its passage through the heater. l A very slightA initial withdrawal of Water suiices to chilling below ther-l supply fuel to the heater burner, and thereby causes all succeeding water to be highly heated in passing to service.

As thus subjected to inflowing cold water, the thermostat is caused to act much more promptly thanif subjectedonly to tank temperature, and the promptness of thermostat action is even more marked in comparison with a system in which the-thermostat acts under the temperature influence of water in a lower region of the tank.

In the modification shown in Figure II ofthe drawings, the thermostat has a highly specialized mounting in the extreme upper region of tank@ temperature influence. In this modication cold water supply pipe 2 is provided with a horizontal extension 15 in which the bulb ofathe'rmostat 13 lies. A tting 16 gives access to the interior of tank 1 at the upper extremity thereof.

In normal operation of the system, that is when no withdrawalis made, water atrthe highest permitted tank temperature rises through fitting 16, and surrounds the bulb .the water in the tank causes hot waterto again enter extension 15 in such manner that the thermostat is subjected wholly to its influence.

Advantages of myY improved water heater are the instantaneous delivery ofhot water at'thc faucet, and the continued delivery of a relatively great volume of water` without appreciable drop in. faucet temperature.

. There is furtherthe advantage, based on the manner in which the control thermostat is influenced, ofmaintaining a lower average tank temperature at all times, and economizing in fuel consumption by lessening radiation loss in theupper region of the tank. My water heater, to the fullest extent yet realized, combines the advantages of an instantaneous water heater with the advantages of a tank type waterheater.

As a specific example, my water heater, when constructed'with a 15 gallon tank and a 25,000 B. t. u. coil, delivers water atatemperature above 110 Fahrenheit fortan indeiinitetime. Extremely low rates-of flow produce rather high, but not. dangerous,fau cet temperatures, and the' faucet .temperature may be easily reduced by increasing the volume ofl flow. lThe feature kof faucet temperaturecontrol is governed by heating coil capacity, tank rtemperature (thermostatic control at the tank), and as a controllable element, the rate of flow. l

I have found that my water heater in very large installations is not adequately under faucet control in determining the upper limit of faucet temperature. In installations, therefore, which approximate or exceed a tank capacity 6() gallons and a 45,000 B. t. u. coil I prefer to add automatic means for limiting positively faucet temperature.

Figure III of the drawings illustrates the use of an independent thermostat to definitely limit the temperature of the water in the service branch pipe 8. In such modification the loop of gas line 10 lying between pilot burner 11 and main burner 5 is greatly extended, as for a yard or more, along service branch 8. This extended portion of gas line 10 has therein a valve 17, which is under the control of a thermostat 18 in the pipe 8.

This thermostat 18 controls only vthe temperature of service water to the faucet to cut off the gas supply to the burner when a predetermined tempera-ture for service water has been exceeded. Y

The two thermostats 13 and 18 do not act in a differential manner, and do not either of them interfere with the action of the other; one acting to control tank temperature, and the other acting to control service water temperature which is materially higher than tank temperature. When its action in cutting off gas supply has lowered the temperature of the water in pipe 8 to the point of safety, thermostat 18 gradually opens valve 17, and restores complete control of the system to thermostat 13. As explained thermostat 13 closes its associated valve 12 only at such time ascessationof water withdrawal has permitted tank temperature to be again built up to the normal carrying point.

I claim as my invention:

1. In a water heater having a circulation system comprising a storage tank, a heating element, a cold water line entering vat the upper end of the storage. tank, an outflow line at the lower end ofthe storage tank leading to the inlet end of the heating ele-ment, a branched discharge pipe from the outlet end of the heating element having one branch thereof leading to service and another branch thereof discharging intermediate the height of the tank and having therein means preventing substantial return flow through that branch to the heating element or to service; the combination of a burner for the heating element, a gas supply line tosaid burner, and a control thermostat subjected by its position of mounting to the direct chillingl effect of the cold water line to the tank upon and during service withdrawals of water from the circulating system and subjected to the effect of tank water temperature in the extreme upper region of the tank in periods between service Withdrawals of water.

2. The combination of the next preceding claim in which the thermostat is mounted in an extension of the cold water supply line in a position wholly outside the storage tank, and in which by a connection from the extreme upper region of the tank to the extension of the cold water supply line in which the thermostat is mounted the thermostat is subjected to tank water temperature in the extreme upper region of the tank during periods between service withdrawals of water.

3. In a water heater having a circulation system comprising a storage tank, a heating element, a cold water line entering at the upper end of the storage tank, an outflow line at the lower end of the storage tank leading to the inlet end of the heating element, a branched discharge pipe from the outlet end of the heating element having one branch thereoflleading to service and another branch thereof discharging intermediate the height of the tank and having therein means preventing substantial return flow through that branch to the heating ele-ment or to service; the combination of a burner for the heating element, a Vgas supply line to said burner, a main control thermostat subjected by its position of mounting to the direct chilling effect of the cold water supply line to the tank upon service withdrawals of water from the circulating system and subjected to the effect of tank water temperature in the eXtreme upper region of the tank in periods between service withdrawals of water, and a thermostat disposed in the service branch pipe from the heating element to service and acting independently of the main control thermostat during service withdrawals of water to impose an upper limit of temperature 0n Water passing from the heating element to service.

4. The combination of the next preceding claim in which the main control thermostat is mounted in an extension of the cold water supply line in a position wholly outside the storage. tank, and inv which by a connection from the extreme upper region of the tank to the extension of the cold water supply line in which the main control thermostat is mounted the thermostat is subjected to tank water temperature in the extreme upper region of the tank during periodsl between service withdrawals of water.

In testimony whereof I have hereunto set my hand.

DONALD B. WILLIAMSON.

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