US2153108A - Steam heating system - Google Patents

Description

April 4, 1939- A. F. UNDERwooD 2,153,108 l STEAM HEATING SYSTEM Filed Dec. 30, 1952 2 SheetS-Sheet l /f gmmntoz /4 l Wmy,%my%.

April 4, 1939. A F. uNDERwooD STEAM HEATING SYSTEM 2 Sheets-*Sheet 2 Filed Dec. 30, 1932 Patented Apr. 4, 1939 @UNITED STATES APATENT OFFICE Y STEAM HEATING SYSTEM Arthur F. Underwood, Detroit, Mich., assignor, by

mesne assignments, to General Motors Corporation, Detroit,uMich., a.y corporation of Dela- Application December 3o, 1932, serial No. 649,495

` l claims. (ci. zar-12.3)

amount of liquid inthe steam generator `or boiler so as to maintain a substantially constant low 'pressure regardless of changes in exhaust gas temperatures whichmay varyfrom an average of 500 F. at low car speeds to 1350" F. at higher car speeds. i f I I,

As willbe more fully described hereinafter, Vthis control of pressure in the system consists in the provision of a `controlor expansion tank which is open to the atmosphere and is positioned above l and connected to the steamgenerator so that when any pressure is developed. in the generator,

" liquid will beforcedtherefrom. upwardly toward or intothistankto thereby reduce the quantity of liquid whichis available ink the steam generator and therebylimit the maximum in pressure which may be ldeveloped anywhere in the systemr so that it will never exceed that pressure required to raise the liquid from the generator to the expansionv tank. Otherl features of my invention and theA particular advantages of the same will appear from the following detailed description of the structure and operation-ofthe embodiments illustrated in the accompanying drawings, in which.: y

Figure 1 is a side elevation with 'parts in section of one embodiment of my' heating; system as applied to an automotive vehicle.`

Figure 2 is an enlarged vertical sectional view takenon the line 2-2Vof .Figure '1 A Figure 3 is a` sideA elevation 'partly in section of the'expansion tank and condenser taken on l-ine 3-"-3 of Figurel".`

Figure 4 is a 'sideelevationsimilar toFigure l but illustrating afurther embodiment of my. heating system. Figure 5 is an enlarged horizontal sectional view taken on the line 5 5 of Figure 4.

Figure 6 is a sectional view taken on line `E---li of Figure 5.

Referring rst to both'Figure 1 and Figure 4, there hasl been shown diagrammatically only those portions of the usual automotive vehicle which are necessary for an understanding of the application of my improved heating system thereto. The internal combustion engine is indicated generally` at l as located in the engine compart- 4ment which is separated from the body compartment by the usual dash 2 and floor board 3. This engine includes the usual exhaust manifold 4 and the usual exhaust pipe of which there is shown a portion 5. It will be understood that the engine is also provided with the usual cooling fan (not shown) and in this and other respects is generally similar to standard practice.

Referring now to the specic embodiment of my invention which has been illustrated in Figures 1, 2 and 3, the principal parts of the heating system consist of a steam generator or boiler unit 6, a heater unit indicated generally at 1 and an expansion tank and condenser unit 8.

The boiler 6 preferably consists of steel or alloy tubing which is attened and secured within the exhaust pipe preferably beneath the point of attachment thereof to the exhaust manifold. As indicated, this portion of the exhaust pipe is generally extended vertically so that the boiler s may be placed in a substantially vertical position to permit the attachment of a steam supply conduit adjacent its upper end and a condensate return conduit adjacent its lower end. To secure the boiler to the exhaust pipe and provide for the steam supply and condensate return thereto, an externally threaded fitting 1 may be welded to the boiler adjacent each end thereof and in assembly the boiler may be inserted from the upper end of the exhaust pipe and the fittings passed outwardly throughholes which are provided in the exhaust pipe and then clamped thereto by means of a nut 8 externally applied to each fitting, suchas is indicated with reference to the upper tting or connection to the boiler which is located below the upper end of the boiler for a reason which will be given in the description of the operation of the entire system.

The upper fitting of the boiler is provided with a metal extension 9 to which is secured at its outer end a section of rubber hose I0 which functions both as a steam supply and condensate return conduit. Intermediate its ends the extension 9 is connected to a separate condensate return conduit ll which extends downwardly to be connected with the lower end ofthe boiler. Withinthe extension 9 there is a short section of metal tubing I2 extending. from the fitting to a point beyond the connection to the return conduit Il so as to admit the steam supply to the common conduit III at a point beyond the separate return conduit for the condensate, and to"y further prevent the steam from interfering with the return of condensate, the tube I2 is shown as located above the center of both the boiler fitting 'I' and the extension 9. For convenience the filling the system with only a .predetermined amount of liquid, there is provided a removable V filling capy or plug I3 adjacent the upper end of` the separatereturn conduit II.

The `lower fitting of the boiler has not. been shown in detail but it should be noted that the lower end of the boiler and the fitting or extension yI4 thereof is inclined downwardly and the return conduit I I is connected thereto adjacent the boiler at a point intermediate the boiler and the connection of the fitting or extension I4 to the control conduit -I-E leading to the expansion tank and condenser unit 8. The heater unit 'I has been shown as generally` similar to units now used in hot water car heatersystems, being mounted on the dash 2 within the,

body compartment and consisting of a radiator IB with an electric motor I1 and fan I8 for' creating a forced circulation. of air through the radiator. It will be readily ,understood that this particular type of heatingI unit isvnot an vessential feature of my heating system but any known type of radiator unit may be employed and located either within the body compartment or outside of the same withsuitable distributing ducts for the heated air, and with or without forced circulation.

In the type of heater unit which has been illustrated, any conventional radiator core may be used, but preferably one in which the passages are of fairly lowvrestrictiom since the condensate must run downwardly through the same passages through which the steam rises to the top of the radiator, As clearly indicated in Figure 1, the

steam supply and condensate return conduit III is connected to the lower end of the radiator I6 and the radiator is provided at its upper end with an opening I9 which in the embodiment of my invention illustrated in Figures 1 to 3 is connected tothe expansion tank and condenser unit 8 by conduit.

Within the upper'end lof 'the radiator is a thermostatically operated valve to substantially close'the.opening I9 when the radiator becomes lled with steam. `This valve is shown in Figure 2 as consisting ofl a flat disc 2l mounted beneaththe opening I9 on the free end of a bi-metal arm 2`2 constituted by stripsof metal of such different characteristics of expansion that the disc 2| willy move to substantially close the opening I9 at a temperaturewithin the radiator of approximately 210 F. valve has been described as substantially closing the opening in the upper end of the radiator, sincethere is some smallieakage past the type kof valve illustrated which has a definite function which will be noted hereinafter in the description of the operation of the entire System.

o The `expansion tank and condenser unit 8 is shown in Figure 3 as consisting `of the tank 2i land superposed condenser 22 within ythe casing 2 3. The condenser may comprise merely a small sectionof radiator core open at its bottom to the tank 2Iand opening atits top to the atmosphere throughthe casing 2'3 by means of the bent tube 24, As shown in'. Figures 1 and 3, the fluid control conduit I5 from the boiler lsconnected to the bottom of the tank 2I andthe conduit 20 haustgases' will soon thaw out from the radiator is connected to the tank 21|' adjacent its bottom.

In describing the operation of the embodiment shown in Figures 1 to.3, it is desired to first call attention to the location of the separate return conduit' II and the lower portion of the conduit I5 as adjacent to each other and to the exhaust pipe 5, and also to the relative location of the lradiator unit 1 and expansion tank and condenser lunit 8 horizontally above the boiler I so that complete drainage will be afforded to the latter. It is also preferable to position the'expansion tank and condenser unit 8 adjacent the forward end of the engine I in proximity to the usual engine cooling fan (not shown) so that such unit will be cooled by the circulation of lengine'cooling air.

It has been found that certain disadvantages which accompany the use o ffi anti-freezing solutions-the present system has been so designed as to prevent injury and operate properly'even though freezing of .the water shouldk occur during periods in whichthe heating system is not in use, or in other words. when the'engine is not in operation. Let us assume, for instance. that the heating system has Just been installed. 'Ihe lling plug I3 would beremoved and an l amount oi' water introduced until over-flow occurs through the filling opening which would thereafter be closed `by the filling plug. It will be noted that this filling plug opening is so located that the maximum amount' of water' which may be introduced into the system will be contained within the major `portionof the boiler within the exhaust pipe and those portions of the conduits II and I 5 which are adjacent the exwater is preferably the best medium for producing steam, and in view oi haust pipe 5. Therefore. if this liquid freezes, it

lmay expand slightly without injury to the system and whenever the engine is started the hot exthe entire body of liquid. y

In normal operation, when, the engine is started, the hot exhaust gases coming into contact with the boiler surface heats the liquid in the boiler vforming steam winch passes through the steam supply conduit I0 to the radiator I6, where it is condensed by heat lradiation which is facilitated by-the air circulating fan. This condensate returns through lthe conduit I0 to the lover-now pool formed within the extension l from` where it is returned to the bottom of the boilerthrough the return conduit II.

The boiler 6 is constructed of a substantially vertical tube which has a s uiliciently large passage when flattened to ail'ord the.. minimum restriction, since if too restrictive, the sudden formation of steam at the entering point will push the incoming liquid'from the boiler instead of pushing the steam to the heater unit. Also the steam outlet isiocated several inches from 4the top of the boiler vso that any liquid which might be forced to the topy of theboiler -by rapid steam* formation will `not pass into the steam supply conduit but will be turned into steam or back to the lower part of the boiler.

lialll As the radiator I6 iirst becomes illled with steam, the air within the radiator, is forced through the conduit 20 and expelled through the tank 2| -and condenser t2 to the atmosphere. When substantially all air end of the'radiator to prevent the escape of substantially all of the steam .vapor in the radiator.

e has been expelled,` y contact of the steam with the bi-metal arm-22 y j substantially closes the opening I9 in the upper aisance gas would rise to the top of the radiator andy gradually decrease the 'steam capacity sufilciently to seriously interfere with the heat radiation from the radiator, making it necessary to provide some means for escape of this gas. In addition to possible impurities in'the water to produce this gas, it has been primarily thought tol be formedyby liberation of hydrogen by the reaction of the water with the iron of the boiler at high temperal f tures. Regardless of the real source oi' this fixed s gas, -it will beapparent that Ithe provision of some leakagev past the thermostaticvalve in the upper end of the radiator permits this gas to escape to the atmosphere through the condenser 22 which prevents'such'small-amount of steam as might also-escape past the thermostatlc valve from being lost with consequent reduction in the amount of liquid which would require the addil tion. of more liquid at indeterminate intervals,

, las

`It will be obvious that withithe exhaust temperatures which are available `for steam generation, more steam will be generated than can be condensed in the'ra'diator and the expansion tank andv condenser unit-3 is therefore connected to the bottom of thefboiler by -the conduit i 5 so thatthe liquid level `within the boiler will be lowered automatically on thegeneration of any pressure within'the upperend of the boiler by forcing the liquid from the bottom ofV the boiler upwardly toward or intojthe expansion tank, and at high engine speeds. it will be found that there' is verylittle liquidin the boiler and most of it will be inthel Aexpansion tank. Also (it will be .readily seen that when the radiator is completely filled with steam,v a pressure will be maintained whichisequalto the head oi' liquid within .theV expansion.4 tank theV conduit from the same'to; the 'boiler.` It will also be obvious that whenever the pressurefalls below this maximum,

` liquidwill be returned to the boiler from the expansion tank and its connecting conduit and a pointof pressure equilibrium will be'almost constantly maintained.

` ,l In addition to preventing the Vescaper of any steam vapors which may leak past the thermostatically operated valve in the radiator, the condenser 22' is provided above the expansion tanky 2|' to prevent the loss of any vapors which may begiven ou by the liquid within this tank, and as 'has -been noted hereabove, the efficiency of the condenser is preferably increased bylocating the same adjacent the engine cooling fan` Ordinarily, the liquid in Ithe expansion tank is at a sumciently low temperature that no vaporswould be produced therein, but if the engine is first started at high speeds,rsubstantially all of the liquid in' the boiler would be heated and on generation of steam, a large proportion of ythis heated liquidl would be suddenly forced to the expansion tank. Under these conditions, however, the condenser would function to substantially entirely prevent vaporloss. 'I'he'escape of vapor is further prevented or reducedby. returning thehighly heated vcondensate from the radiator to the boiler at a point between the boiler and the connection to tothe expansion tank and 4condenser unit 'and the provision of a small leakage tank and condenser 3I mounted directly on the top of the heater unit 1. 'I'here has also been provided an accessory reserve tank 32 to facilitate filling or replenishing the supply of liquid in thesystem.

With reference to the small leakage tank 30 and condenser 3l, which is open to the atmosphere, the same functions in conjunction with the thermostatically operated valve within the upper end of the radiator to provide for the escape of air from the radiator until the latter becomes illled with steam and thereafter functions to receive and condense such small leakage as there may be past the thermostatically operated valve and permits the escape of any gas which may be generi ated in the system. Such steam vapors as may leak pastv the thermostatically operated valve and .be condensed by the small condenser 3| will be A`retained in the leakage tank 30 and returned to the system Whenever the 'upper end of the radiator cools suiliciently to permit any substantial opening of the thermostatically operated valve.

'Ihe reserve tank 32 is preferably located on the dash within the engine compartment and is connected to the system by conduit 33 at a point in the condensate return conduit Il corresponding to the location of the filling opening and plug in the embodiment of my invention shown in Figure l. A valve unit 34 is provided in the conduit 33 adjacent the connection to conduit Il. `'I'his valve unit 34, as shown in detail in Figures 5 and 6, includes in addition to the liquid passage 35 leading to the conduit Il, a furtherv passage 36 opening to the atmosphere. Both the passage 35 and the passage 36 are adapted to be opened simultaneously by manual rotation of the plug valve 31 which is screw-threaded on the valve unit as at 38. As will be apparent, when the valve is operated to admit liquid to the system, the liquid will runout of the passage 38 as any gas caused by decomposition and which might eventually interfere with proper operation of the system by restricting the heating capacity of the radiator would not be retained in the system but would be exhausted by leakage through the expansion tank and condenser unit of Figure l or the small leakage tank and condenser unit of Figure 4.

No means has been provided in either of the illustrated systems to entirely stop operation thereof, since this is considered unnecesary with the type of heating unit shown in which substantially no heat is dissipated by the radiator without the forced air circulation afforded by the fan which may be turned off br its speed regulated in accordance with usual practice. 4Iii found desirable, however, with this or other types of heating units, a manually operable shut-oft valve could be provided and located, for instance, in the steam supply and condensate return conduit.

From the above detailed description, it will be seen that a very simple and yet highly effectivev While in accordance with the vprovisionsof 'the statutes I have illustrated and described herein two embodiments of my invention, it will be apparent that changes maybe made in the form ofv the systems disclosed without distinguishing' from the spirit of my invention as set forth in the appended claims.- certain features of my invention may be used to advantage without a corresponding use of other features.

u What I claim as my invention is:

.0 a vaporizable liquid and associated with said 'exhaust pipe so as to be heated by the exhaust gases passing therethrough, means connecting said generator to said radiator forthe supply of steam` to the radiator and the return of condensate to the generator, and means to automatically control the quantity of steam generatedby automatically varying the amount of liquid in said generator comprising a vented expansion tank, means connecting said generator to said expansion tank into which liquid will be forced by steam pressure developed in said generator, said expansion tank being continuously vented to the atmosphere through an air cooled condenser to condense any vapors from the liquid in said tank and return the condensate to the system. Y

2. In a steamheating system, thecombination with a boiler adapted to contain a `vaporizable liquid and generate steam on application of heat thereto,a radiator, means connecting said boiler to said radiator for the supply of steam to the u radiator and the return of condensate to the boiler, an expansion tank, means connecting said tank to said boiler to receive liquid therefrom, a vented condenser on said expansion tank to receive steam and return the condensate to the system, and means connecting said radiator to said condenser with a thermostatically operated It will also be yapparent that valve in said radiator which is adapted to substantially close said connecting means to said condenser when said radiator becomes fllled with steam.

3. A steam heating system for motor vehicles comprising in combination with the vehicle en-v gine and its exhaust pipe, a radiator for the vehicle, a steam generator adapted to contain a vaporizable liquid and associated ,with said exrhaust pipe so as to be heated by the exhaust Ygases passing therethrough, means connecting said generator: to said radiator for the supply o! steamto the radiator and the return of condensate to the. generator, and means to automatically control the quantity of steam generated by automatically varyingthe' amount of liquid in said generator, comprising-an expansion tank and condenser unit connected to said generator to receive liquid therefrom, said expansion tank and condenserv unit being positioned adjacent the front end of the vehicle engine so as to be cooled by the circulation of air thereover.

4. In a steamheating system, the combination with a boiler adapted to contain a' vaporizable liquid and generate steam on application of heat thereto, a radiator, means connecting said boiler to said radiatoriorthe supply of steam to the radiator and the. return ofcondensate to the boiler, a vented expansion tank connected to said boiler, and means to supply liquid to said system comprising a separate reserve tank and means including a. manually operable valve for connecting said reserve tank with said system, said valve being provided with an overflow passage which is opened to the atmosphere when-said reserve tank is placed in communication'with said system to limit the amount of ,liquid which may be suppliedto said system to that which may be contained therein below Athe horizontal level of said valve passage.

5. In alsteam heating system, the combination with a boiler adapted to containv a vaporizable liquid and generate steam on application of heat thereto, a radiator, means connecting said boiler to said radiator for the supply of steam to the radiator and the return of condensate to the boiler, alvented expansion tank so connected to said boiler as to receive liquid therefrom and automatically control the amount of liquid available for steam generation therein, a, relatively restricted connection from a normal point of air accumulation in said radiator to said expansion tank, and a thermostatically operated valve in said radiator to substantially close the connection of said radiator to said expansion tank when said ARTHUR F. UNDERWOOD.

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