US1618177A - Heating system - Google Patents

Description

y M. ELLIS HEATING -SYSTEM Filed Aprii 25.

' w L9 La 1921 2 Shank-Sheet; 1

finder Feb. 2 9 L. M. ELLIS HQEATING SYSTITJM 2 Sheets-Sheet 2 Filed April 25. 1921 F f. A v .T m A wfi Q Patented Feb. 22 ,'1"9 27.

UNITED STATES P ATENT OFFICE.

LEWIS M. ELLIS, or CHICAGO, ILLINOIS, ASSIGNOR TO TUBAL BOILER co.-, or CHICAGO,

ILLINOIS, A CORPORATION or ILLINOIS.

ima'rmo SYSTEM.

Applicationflled Apri1 25, 1921'. Serial No. 434,381, I q,

The present invention relates to heating systems, and is an improvement upon. the heating system disclosed in my prior Patent No. 1,399,052, issued December 6, 1921.

In this patent I have disclosed a system of heating having particular application to ovens, kilns and other heating "devices in which it is required .to maintain relatively high temperatures, ranging in the neigh borhood of between O degrees F. to- 800 degrees F. These ovens or kilns have illustration in enameling ovens and the like. This heating system is characterized by the use of a superheated vapor or gas which is mechanically circulated through the system at a sufliciently high speed to eliminate any tendency to condense in the oven co1l or other heat radiating device. The vapor'or gas is preferably, thouglr not essentially steam, and when employing this. medlum the system includes a superheater for adding heat to the steam, the oven, kiln or other heating device; and a pump, compressor, or the like which functions as an 1mpell1ng de-' vice for moving the steam through -the cir cuit. A boiler or other source of steam or vapor is employed formaking up the losses incurred in running and for supplylng the initial body of fluid medium. The theory 0 of mechanically circulating the superheated steam at a relatively rapid ,rate through the oven coil is to prevent the temperature of the steam from dropping below the saturation point in the oven coil, and preferably throughout the circuit, and to increase the heating efficiency of the coil by clrculatmg the, heat conducting medium therethrough at a relatively highspeed.

One of the principal objects of the invention'is to increase the efl'iciency of the circulating pump or blower by so disposing 1t in the system that it handles a relatively smaller or minimum volume of steam and at a point in the cycle where this steam 1s of relatively low temperature. The reduced volume of steam permits of a smaller circulating device with a roportionate reduction in heat absorption y the circulating de vice, and the lower temperature of the steam avoids overheating of the-device and other mechanical difficulties.

A further object of v the invention is to provide control means responsive to the temperature in the oven, or'in the oven 0011,

for controlling. the rate of circulation through the system, or for rendering inefi'ectl Ve the circulating device so as to interrupt circulation at a predetermined temperature. Afurther object isto provide means for venting the circuit into a region of considerably lower pressure at predetermined times n the operation of the-system, such as for tlji e purpose-of accelerating the rate of flow o purpose of bringing the oven temperature u to its desired value, or for more quickly imtiatin'g the operation of the system.

A-further and invention isv to provide means which will function as an elastic reservoir for releasing heat and pressure from the circuit-during periods when the oven is absorbingless than the normal or maximum amount of heat. During thesperiods the temperature of the superheated steam must be maintained at substantially the same point as during the normal or high working conditions of'the oven, but vowing to the fact that a smaller quantity of heat is being absorbed in the oven, a large percentage of the original superheat given to the steam at the superheate'r is returned to the boiler point of the'circuit. Here this superheat is largely absorbed in the steam through the oven coil for the prominent object of the v the boiler, with the result that increased generation of steam follows. Where a very large percentage of the original superheat is returned from the oven, sufficient, when added to the external firing of the boiler, to. generate an excessive quantity of steam in the boiler. The result is tion I contemplate an efficient and economi-' this heat may be I thatthe steam pressure in the circuit'tends to rise to an undesirable point, either from the stand-point of safety, or .from. the fact cal method of compensating or absorbing these fluctuations in temperature and pressure by associating with the boiler'or circuit either'a steam engine, a heating appa-v ratus, or any secondary heat absorbing means, and by regulating the external firing of the boiler either manually orautomati- 1 cally to controlthe external heat input to the boiler in accordance withthe pressure in the system. According tothis method,

the boiler is externally fired to supply a sub- .sta'nti'ally constantsteam pressure of the de- "sired degree suitable for the oven circuit and for the secondary heat absorbing means. When the quantity of superheat imparted to .the steam in the oven clrcuit is in excess of the oven requirements the excess superheat heats the boiler internally and of itself or with the assistance of the external firingthis internal heat tends to develop an excessive steam pressure. At this point, however, the

external firing of the boiler is cut down either by the attendant at the boiler or by automatic means. Owing to the forced circulation of the steam in the circuit'andthe high degree of superheat imparted thereto, the heat returned to the boiler from the This secondary'heat absorbing means is provided by the steam engine, steam heating apparatus, or other means, drawing steam from' theboiler point of the circuit. The relative capacities of the boiler and of the secondary heat absorbing means are pref erably such as to insure that "the secondary heat absorbing means will withdraw steam from the boiler at a rate equal to or greater than the highest possible rate of steam generation caused by the returned superheat from the oven, so that the secondary heat absorbin means is always capable o'f'utilizing all 0% the returned supcrheat in order to avoid the generation of the excessive pressures in the system. From the foregoing it will be seen that the boiler, the secondary heat absorbing means, and the regulated firing of the boiler thus constitute an elastic thermal reservoir for withdrawing heat and pressure from the circuit during low Working periods of the oven. Thus the-system is made capable of meeting widely varying demands, but at the'same time, maximum heat economy is retained. The above fea ture of my invention may have the further aspect of efficiently-utilizing the exhaust steam of lower temperature which is discharged from the oven coil' by secondary heat absorbing means having particular aptitude for this character of steam, as I shall hereinafter describe.

The foregoing objects will more clearly appear in the accompanying description of a preferred embodiment of my invention.

In the drawings illustrating this embodiment: 1

Figure liis a diagrammatic layout of one form of my improved system, and

' Figure 2 is a Si i1 r view of another form of the system employing thermal controls for regulating the circulation through'the fully described 1.. the above mentioned patent, a boiler 4, which may be of any suitable "type and capacity capable of generating the required pressure and volume of steam, supplies steam which is either saturated, or of a relatively low super-heat. The steam is discharged from this boiler through a pipe 6 which extends to the intake of a circulating device 7. This chculating device may be of the reciprocating higher pressure than that atthe steam. The superheater illustrated is 7 provided with a suitable burner, although it is to be understood that any controllable source of heat may be employed. The burner is provided with a regulating valve 11 which controls the amount of fuel burned under the superheater.- The rate of heat delivery to the superheater 10 is controlled heat transferring medium as it passes into the hot end of. the oven or kiln 5. For this purpose, I have provided a temperature responsive element 12 for regulating the fuel controlvzilve 11. The temperature responsire element 12, instead of being subjected merely to the temperature of the steam delivercd, may be subjected to the temperature of the kiln, or to the temperature of the exhaust steam discharged from the oven in accordance with the temperature of the coil. From the temperature responsive element 12 the highly superheated steam flows through pipe 13 into the-end of a heat radiating coil 14 in the oven 5. The coil 14 may be in the form of a single sinuated coil as illustrated, or it may consist of-a plurality of coils connected in: parallel between inlet and outlet headers. From the discharge end of, the coil 14 the steam is conducted back to the boiler 4 by way of pipe. 15.

Any suitable secondary heat absorbing meansmay' be connected to the boiler or to the circuit for cooperating the boiler in providing an elastic thermal reservoir or excess heat absorbing means. At 16 I have shown an ordinary steam engine which may be run either constantly or intermittently,

upon the return of excess heat to the boiler, this, engine serving to drive any suitable of, pipe 17,41 suitable valve 17 being in power apparatus. The boiler isconnected tol this secondary heat absorbing means by way of the superheater would require a'large'.

furnace for the boiler 4 may be either manual or automatic, both bein contemplated responsive element. 18' in the ipe line 17 or at any other point-in the system preferably adjacent the boiler, and having this pressure responsive element control a fuel valve 19 and thereby regulate the external -firing of the boiler.

In the operation of the system, the blower 7' circulates the steam through the oven coil 14 so fast that the drop in tempera" ture of the steam by contact with the sides of the tube 14 does not reduce the temperature of the steam tothe point of saturation. 'l'hus, the drop in temperature of the steam 'is controlled by the speed of movement of the steam and it is possible to hold the mmperature of the coil very closely'to a predetermined figure with only asmall thermal drop, and consequently with an even distribution of heat throughout the coil. The oven temperatures which it is possible to obtain by this high speed circulation of superheatedsteam' are far in excess of those ordinarily possible with saturated. steam. For example, oven temperatures of from 500 degrees F. to 600 degrees I11 canbe maintained throughout the oven or'kiin, with pressures "in the neighborhood of 100 or 150 pounds. .l/Vith saturated steam these temperatures would involve prohibitive pressures. j

It will be noted that the blower 7 handles only the saturated steam passing from the boiler 4 to the superheater-'10. This saturated steam has least volume and confequently the'blower 7 can be of smaller size with proportionately less heat loss by conduction through the walls of the blower..

Owing to the high superheat which must be imparted to the steam in the superheater 10 the expansion of the steam is relatively large, and the handling of this expanded, high temperature steam on the outlet side blower and involve unnecessary heat loss, even where the blower is disposed at the dis- 0 charge end of the heating coil 14. More'- over. the lowertemperatures of the saturated steam between the boiler 4 and the superheater 10 avoid large thermal losses,

overheated bearings, and other mechanicaldisadvantages incident to thefiow of a very,

high temperature gas through a 'blowcr.

The superheatreturned from' the oven to the boiler point of the-circuit has the tendency to generate steam in the boiler,in quantities depending upon the amount of superheat and the balance or adjustment of the system. ,VVere provision not made for taking care ofthis returned superheat the generation pf steam therefrom might at times develop undesirable pressures in the described.

system. Any such increase in pressure would not influence the control element 12 as .thiselement is only responsive to temperatures. According to the present method, where the firing of the boiler is man ually controlled the attendant upon noting any such increase in pressure cuts down on the external firing. It is assumed that during this time the engine or other heat absorbing means is continuously withdrawing heat from the boiler. The excess heat may thus be drawn directly to the engine or indirectly in the form of steam vaporized in the boiler. The ultimate fact is that the engine requires a continuous supply of heat and when the oven circuit is operating normally a certain percentage of this heat is supplied an excessive percentage of superheat-is returned from the oven this heat is w1thdr'awn the furnace under the boiler, but when from the oven circuit and is fed to the 011- gine, the furnace heat under the boiler being reduced commensurately with the quantity of heat supplied from the oven circuit. \Vhere the firing of the boiler is controlled automatically the generation of pressure in the system beyond a predeterminedpoint' operates automatically to reduce the rate of firing of the boiler. This shifts the thermal balance so that some, or more, of the excess heat from the oven is used in supplyingthe secondary heat absorbing means and less is supplied from the boiler furnace. It will be obvious that the system may have any desired thermal adjustment or balance. For example, a certain percentage of the heat returned from the oven may be supplied to the engine in the form of excess heat even when the oven is absorbing a relatively large amount of heat; or, the system may be so balanced that it is only when the oven is absorbing but little heat that the return heat therefrom is utilized to run the engine.

In the arrangement illustrated in Figure 2, saturated steam is supplied from a boiler 4 through -pipe 6 to the blower 7 ,the blower H in this instance being shunted by a by-pass 20 designed to control the circulation through the system From the"dis charge.

outlet of the blower 7 the steam is con ducted through pipe 9 tothe superheater pipe 13 to the oven coil 14, which may be arranged in either of the forms-previously The temperature of the discharged steam is controlled by the usual temperature responsive element 12 which operates through the valve 11 to govern. the

rate of fuel supply to the burner of-the superheater'lO. For venting the coil 14 to atmosphere or to a region of lower pressure, the discharge end of the coil has an outlet opening 21 controlled by an automatic valve 3- 22. To permit-fof'manual venting of the I coil a. secondary outlet 23 is provided, controlled by a manually operated valve 24. The two outlets 21' and 23 may discharge -to atmosphere,-or may vent into a heating system of lower pressure or any other region of sufliclently low pressure to insure a highly accelerated flow of steam through the coil 14. In the normal operatlon of the system,

the steam is discharged from the coil lfl: into the usual discharge pipe which com municates with a steam main 25 extending I from the boiler 4 to the engine 16. A check valve 26 is'interposed in the pipe 15 to prevent the steam from backing up mtothe coil '1 14 during non-operating intervals of the oven.

. .ture of the oven above a predetermined mmi- V mum, the element 36 has connection 30 with a valve operating device 31 which controls the automaticcva-lve 22.

The same general theory of operatlonpreviously described is characteristic vof this system. However, when thetemperature in t e oven 5 reaches a predetermined maximum, the temperature element 36 responds by openingthe valve 29 through the instrumentality conn'e I circula of the valve operating device 28 and 'ction 27 The result is that the forced "tion of the steam through the system is interrupted by a the steam recirculating through the by-pass 20, and consequently the oven is given an opportunity to cool off,

' whereupon the valve 29 closes and. the circu lationvthrough the oven coil is resumed as -11,.tl'1e temperature responsive element 36 before. *It will be noted that such steam as is circulated throughtthe oven coil is maintained at a substantially constant-temperature by the thermostatic control 12 and valve and valve'29 controlling the existence of a circulation through the oven coil or the vol ume When the oven temperature recedes to a preof steamcirculated therethrough.

determined minimum, the temperature responsive element .36 operates. to open the valve 22 through the instrum tality of the valve operating device 31, thereby causing.

A'gage 3-1 indicates to the fireman or engia rapid discharge of steam from the discharge end oi the oven coil with a conse- Y quent. increase of steam flow through the tomatically closing Whenthe desired 'temoven coil. in augmentation of that created by theblower 7. This results in a'rapid rise (pf-temperature in the oven, the valve 22 au perature is restored. This increased rate oi circulation through. the oven coil for accentu'ated heating of theoven or. for quicklybringing the ove n up to heat may be obtained at any time by the opening-of the manually operated valve 24. The maximum restoration of the desired oven temperature.

The relatively cooler steam from the discharge end of the oven 0011 may be circulated back intothe boiler through the steam .rnain 25; or it maybe mixed with saturated steam drawn from the boiler 'through the steam main 25 for the operation of the engine 16; or this discharge steam from the oven coil maybe utilized for the running of the engine to the exclusion of the saturated l steam from the boiler 4 by the closing of the valve 32 and opening the valve 17". That is to say, by closing the valve 32 and open ing the valve 17 in the pipe line 25, the entire 'volume of steam discharged from the oven coils may be utilized for operating the engine 16. Of course, it would not be practical to "do this except during low'worki'ng periods of theheat radiating'coils. The engine 16 in reality constitutes an independent secondary heat; absorbing means associated with the heating system on the outlet side of the heat radiating coils for utilizing only heat in the vapor discharged from the coils in excess of that required for maintaining apredeterminedpressure in the system. The

engine 16 should, in order to attain the best results in the operation of the system, only be interposed in the'return line of the system when a thermal outlet is needed, or in other Words, when the coils are not functioning at their full capacity. The present "invention, however, should not be limitedto the specific type of secondary m'ea'ns employed, nor to the manner ii -Which it.is specifica'lly associated withthe system, but the invention should only be limited in so far is defined by pended claims.

the scope and spirit of-theap- I In this embodiment I have assumed the 'firin'g of the boiler as being manually. controlled, although an automatic control such" described .may be employed:

as previously neer the pressure in the system. By control ling the external firing of the boiler 4 the attendant can make the boiler and engine. function as a thermal reservoir oroheat absorbi ng'means in precisely thesame manner as before'detcribed. When the 'ovenis returning a relatively large quantity of heat the boiler is fired at a proportionately lower rate. By closing the valve 32 the circulatin action can be interrupted and the entire v ume of steam from the oven can be cliverted into the engine 16.

In the present. form, the boiler 4 and superheater are illustrated as beinglocated in proximity so that the flue gases from the superheater 10 can be conducted through an exhaust flue 33 into the further release of heat from the gases to the Water in the boiler. The thermally responsive element 36 maybe provided with any suit-ablegauge or indicating dial 36' for indicating externally in the oven 5.

I claim: 1. In a heating system, the combinat on in a vapor circuit, said circuit comprising a boiler, a superheater for superheating the the temperature existing vapor to a temperature above the temperature corresponding to the saturated vapor at the pressure prevailing in the system, a

radiator in said circuit for receiving the superheated vapor, and impelling means interposed in said circuit between said boiler and said tion with vapor.

2; In a heating system,

the relatively low temperature a vapor circuit comprising a'boiler, a superheater, a heat radiating coil, anda pump, said superheater heating the vapor to a temperature above the temperature corresponding to the saturated vapor at the pressure prevailing in the system, said heat radiating coil giving off heat from the vapor and reducing the temperature of the same to a point above the corresponding temperature of saturated vapor, said pump moving the vapor away from the radiating coil before the temperature of the vapor drops below the saturathe pressure prevailing in the circuit, said pump being interposed in said circuit between said boiler and said superheater, whereby said pump handles the low temperature steam of minimum volume passingbetween said boiler and said superheater.

3. In combination, vapor generating means, a-vapor superheater, a heat radiator connected thereto, a vapor impelling meansfor driving the vapor through said superheater r and said heat radiator, and means controlled by conditions at said heat radiator for automatically by-passing sa-id vapor impelling means. a

4. In aheating system, vapor generating I means, a vapor sup erl1eater,.a heat radiator connected thereto, a vapor pump for driving the vapor through said superheater and .said heat radiator, a by-pass around said' 7 v vapor-pump,'and

thermally controlled means for automatically controll ng said" by-pass. 5. In a heating system, the combination of a vapor circuit, vapor. generating means,

said circuit including a heater for superboiler 4; for a still radiating coil.

superheater for creating vcirculaheating the vapor, and -a heat radiating device for receiving the superheated vapor, means for circulating the vapor through said circuit, and means for venting said circuit to a region of lower pressure for accelerating the fiow of vapor through said heat radiating device.

6. In a heating system, a vapor generator, a vapor superheater vand a heat radiator connected together in a circuit, a vapor pump for driving the vapor through said circuit, and means for venting said circuit-to accelerate the flow of vapor through said heat radiator. g r

7. In a heating system comprising a vapor circuit, vapor heater in said circuit, a heat radiating coil in said circuit for receiving the superheated vapor, a vapor vapor, and thermally controlled means for automatically venting said circuit to accelerate the tlow of vapor through said heat 8. In aheating system, the combination of vapor generating means, avapor circuit, a vapor superheater in said circuit, an enpump for circulating the closure having a heating coil therein ineluded; in said vapor circuit, a vapor pump tor driving the vapor through said circuit, and thermally controlled means responsive to the temperature in said enclosure for automatically venting the circuit on the outlet side of said heating coil for accelerating the flow of vapor through said coil.

9. In a heating system, the combination of a vapor circuit, vapor generating means, a heater in said circuit for superheatingthe vapor to a temperature above the temperature corresponding to the saturated vapor at the pressure prevailing in .the system, an enclosure comprising a coil in said circuit for giving ott heat from the vapor and reducing the temperature of the vapor to a point above the corresponding temperature of saturated vapor at the same pressure, a blower in said circuit for driving the vapor through said heater and said coil, a

y-pass shunting said blower, a vent in said the vapor in the system including an inlet, and impelling means for circulating the vapor inthe system interposed intermediate the outlet of the vapor generator and the inlet of the superheating means.

' including an outlet, means for superheating "11. In a heating system, aboiler for generating vapor, a superheater forsuperheating the vapor, and a pump for causing the vapor to be. circulated interposed between the mediate an outlet of the boiler and an inletboiler and the nerator, said pump handling only the ow temperature vapor of mimmum' volume'passing between said boiler and said superheater.

12. In a heating system, a boiler for generating vapor, a superheater for superheating the. vapor, radiating means disposedintermediate an outlet of the'said superheaterand an inlet 6f, the boiler for receiving the vapor, and impelling means disposed interof the superheater for circulating the vapor through the system.

13. In a heating system, vapor generating means, -.means for superheating the vapor,-

., radiating means for receiving the superheated vapor, means for causmgthe vapor termined point to accelerate the flow'of the -for taking heat therefrom, means for caus-. ing the steam to flow through the said ra-v superheated vapor through the radiating means;

, 14. In a heating system, a source of steam radiating means for receiving the steam and diati'ng' means, and thermally controlle means associated with the radiating means for automatically ventin the system when 'the temperature within t e radiatingmeans drops below a predetermined point to accelerate the flow of the steam through the ra- 1 diating means.

15. In a -heating' system, means -for gencrating vapor, means for superheating the vapor, heat radiating means for receiving the superheated vapor, means for causing the vapor to be circulated through the system, and thermal means associated with the heat radiating means for venting the sys-'. tem when the temperature of the said heat radiating means falls below a predetermined amount and for by-passing the vapor around the-circulating means toretard the flow of the' vapor before it reaches the heat radiating means when the temperature ;of said heat radiating means exceeds a predetermined point. v

16. In a heating system, a source {of steam,

heat radiating means for. receiving the steam, means for causing the. steam to flow through the said heat radiating means, and

thermal means associated with the heat-rm diating means for venting the system when the temperature of the said heat radiating means falls below a predetermined amount and for by-passing the steam around thesaid second mentioned means toretard the flow of 'the vapor in the system when the temperature of the said heat radiating means exceeds given'amount.\

17 In a heating system, a'source asecond means controlled by the conditions at the said heat radiator for automatically Icy-passing the steam around the first means to retard the flow of the steam in thesystem.

In witness whereof, I hereunto subscribe my name this 13th day of April, 1921.

LEWISMQELLIS,

v of steam, aheat radiator, a first means for causing the steam toflow through the heat radiator, and

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