US1425273A - Storage heater - Google Patents

Description

. J. PABODIE.

STORAGE HEATER.

APPLICATION FILED FEB,18, 1920.

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STORAGE HEATER.

APPLICATION FILED FEB} 18, I920.

Patented Aug. 8 1922.

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ATTORNEY? Nil unlit-en stares were were,

\ ROBE? JEWETT PABODIE, 0F HAYWOOD, ILL I1\T@IS,.A SSIGNOR TO THE GRISCQTJL RUSSELL CUMPANY, OF NEW YQRK, Ni Y A CORJPOTION OF DELAWARE.

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Application filed February 18, mac. Serial no. 359,571.

To allwhomz'twwy ooncemr 7 Be it known that 1, ROBERT Jnwn'r'r Panonm 'a citizen of the United States, residing at aywood, in the county of Cook, State of Illinois, have invented certain new and useful Improvements in Storage Heaters;

and I do hereby declare the following to be a full, clear, and exact description of the invention,'such as will enable others skilled subject to more or less irregular demands.

For instance, in hotels the demand for hot water in the few morning hours is probably greater than all the rest of the day. Also, in industrial plants there is frequently a demand at intervals forlarge quantities of hot water for leaching or similar processes, which must be maintained on hand ready for use.

The heating agent for heaters of this kindis generally steam, particularly where,

as is usually the case, there is a supply of exhaust steam from the power plant or heating plant, and the steam has usually been utilized by running it through a series of U-tubes projecting into theastorage tank or boiler shell containing the water to be heated, the steam condensing in the tubes.

l have found that in heaters of this class the tube surface is not efiicient for heat transfer for. the reason that the steam, being at a low pressure, begins to condense almost immediately upon entering the tubes, covering the interior of the tube surface and adually forming into a stream of liquid at the discharge end of the tube. That is to, say, a tube of suflicient length to distribute the heat through the storage tank is so long that in an ordinary U-tube 'construction the return portion is practically useless for heat transfer.

The object of the present invention is to provide a storage heater construction in which the disadvantages of the U-tube design are obviated, and to this end l have provided a tube construction in which the greater portion of the tube surface operates at approximately the maximum eficiency', at the same time providing aret'urn conduit Specification of Letters Patent.

' Patented Aug. 8,

, for thecondensed steam of ample cross sectionforthe required flow.

My invention also comprises an arrangement of supplemental heater which may be used when necessary to amplify the efiect of the main heating tubes, as will. be more fully described hereinafter.

In the accompanying drawings l have ilhistrated a preferred embodiment of my improved heater both with and without the supplemental heater.

In said drawings,

Figure 1 is a longitudinalsectional view of the heater with the one set of heating tubes; p K

Fig. 2 is a transverse cross sectional view Fig. 3 is a longitudinal sectional View showing an instalation equipped with a supplemental heater.

Fig. 4 is a view similar-to Fig. 1 showing a modified form of heating element; and

Fig. 5 is a transverse sectional view taken on line 55 of Fig. 4:. I

Referring to the drawings, particularly to Figs. 1 and" 2, 1 indicates the shell or storage tank -preferably- .formed of boiler late of suitable weight/one end of which is provided 'below the middle line. with an opening 3 of semi-circular shape, as indicated in Fig. 2. Againstthis opening there is riveted a steam drum. 4 in which the heating tubes are set, the tubes being brazed or expanded in place in the usual manner.

In order for the tubes to extend parallel with the shell wall, the drum is provided with. a raised flange 7 of greater. depth on. its lower side, fitting the margin of the opening and riveted to' the shell, the rivets preferably going through a reinforcing .collar 8 within the shell. 1 u The steam drum is divided by a partition 9 into two compartments, an upper compartment 10 comprising practically the entire cross section of the drum, and a small lower compartment 10*. with the upper compartment is a bank of steam tubes 5 of'small diameter extending Communicating substantially across the width of the shell to provide a lar e and well distributed heat ing surface. c mnected to the lower com partment' 10 is a single return pipe 11 of much'larger diameter than the steam tubes so as to have a large cross sectional areafon its surface, the pipe being designed to return to the drum the water of condensation formed 'in the heating tubes.

The free ends of the tubes and pipes are set in a tube .plate 12which is entirely sup-' ported b the tubes and pipe and the plate is pro'vi ed with a cover 13 formin acommon chamber for all the tubes an the return pipe 11 which is inclined'as shown to facilitate the flow of the water. The steam is admitted to the upper compartment 10 of the steam drum froma suitable source of exhaust steam, while the lower compartment I connects with the drain or'hot well to which upwardthrough the steam and then down and across ing tubes.

. .the condensate is delivered. '15 from the steam inlet with an inlet for the The shell is provided near the end away water to be heated, which inlet is preferably in the" form of a nozzle 15 directed toward the heating pipes so that the incoming water will follow the normal circulation ipes, thence toward the rear of the shell across its top the bottom to the front of the shell and through the heat- In addition to the inlet opening the shell is preferably provided with a blowdown 16 for drainage and with a delivery pipe 17 at the top of the shell.

Theoperation of m improved heater will now be described. he steam admitted to the large compartment 10of the steam drum passes through all the small tubes into the drum 13 atthe other end, the small tubes having suificient surface to condense substan- 35 tially all the steam, hence the return through the pipe 11 is merely water which will flow readil. into .the lower or'discharge compartment'lO of the steam drum and to the drain pipe 18. The small tubes 5 not only have a verylarge heating surface in proportion to their cross-sectional area, but also. have the further advantage that, due to their small bore, the water which condenses in the tubes -will not accumulate on the surface, but will the drum 1?).

' greatly to the cost of the apparatus, but instead the seat of the steam drum will be fitted {to the end of the reservoir so as to tilt the tubes slightly downward at their inner ends, that is to say, the flange 7 at the bottom of the steam drum will be slightly'deepe'r than over the old U-tube type of heater.

necessitated reservoir.

This apparatus hasdecided advanta e's he by. the curve of the end of the drum 13 within the reservoir forms a collect ing chamber for the condensed steam from the small heating tubes and thereby relieves the back pressure which would be present 7 were the tubes themselves bent to form re turn connections. As the small tubes are straight, they may be readily withdrawn and replaced through the tube sheet at the outer end by simply removing the cap and without taliin the apparatus down.

11 ture in which I have provided an auxiliary heater 21 in addition to the main heater, the auxiliary heater projecting into the reservoir above the main heater and below the outlet port 22. This heater 'is shown as of the same type as the main heater, only smaller, which construction is particularly advan: tageous for this purpose as it permits a free passage of water through the tubes to the outlet' and will notinterfere with thefiow of the water whether in use or not. Thecontrol valve of the steam in the pipe 23 of the auxiliary heatertwill -preferably be provided with thermostatic control regulated by the temperatureof the water in the reservoir to admit the steam to the auxiliary heater when the'temperature of the water in the reservoir falls below the minimum temperature at which it is desired'to maintain the water.

My improvements are, as stated, of particular advantage for heating water for the purposes described, but it will be underig. 3 there is shown a modified struc- I stood that the same arrangement of heating tubes may be used with advantage in boilers, evaporators, etc., particularly low pressure apparatus where t condensate and the steam velocit is small.

In the foregoing specification have described the return passage as consisting of a single tube of relatively large diameter. I may, however, employ a return passage consisting of a num er of tubes of the same size 'as those constitutin or of a different size, as esired. Figs. 4 and 5 show a heater in which the return passa e consists of a plurality of tubeswll of t e same diameter as the tubes 5 constituting the principal fluid passage. x v The tube bundle consistin of the tubes 5 and 11 is here shown of su stantially circular cross section, although it is to be unere is a large quantityof the main passage,

derstood that it may'assume' any other convenient form'such as, for instance, a semicircular form as shown in Fig. 2. The inner ends of the tubes 5 and 11 are fixed to a floating head to permit free expansion of the tubes under the influence of changes intemperature, and" the outer ends are expanded into the tube sheet 6. The partition 9 serving. to form a steam chamber 101 in communication with the principal body of tubes 5 and an outlet chamber 10 in communication with the tubes 11 constituting "the return passage 'is here shown as formedi'ntegrally with the tube sheet 6. If desired, however, the partition 9 may equally well be cast integrally with the outer cap 25 as may. the sidewalls 4 of the chambers 10 and 10 in which case the tube sheet 6 would consist merely of a disc perforated to receive the tubes and bolted against a cooperating part provided on the shell of the heater.

It will be understood that the following claims are not limited to water heaters, but are intended to include, any apparatus in which the improvements are useful.

It is also to be understood that the invention is not limited to the structural details shown and described, except in so far as they may be recited in the claims.

I claim:

1. In an apparatus of the class described,

a reservoir for the liquid to be heated, a,

heating element comprising a series of tubes projecting into the reservoir for the circulation of the heating medium, said tubes comprising a group of tubes of small bore distributed through the lower portion of the reservoir and having a common intake and a common discharge connection, and a return tube of large cross section connected to.

the common discharge of the small tubes and having a dischar e connection outside the reservoir, a secon smaller heating element of identical construction, and an intake opening in said shell for the liquid to be heated, said intake having a nozzle for directing the flow of the incoming liquid around said heating tubes.

2. In an apparatus of the class described, the combination of a shell to receive the liquid to be heated, a heating element therefor comprising a steam chamber, said chamko ber being small relative to the sectional area of the shell and located substantially below the median line thereof and comprising a tube sheet detachably secured to the exterior of said shell, a group of tubes extending from said sheet into said shell, said group of tubes being divided into two passages, one of said passages being of lesser total cross sectional area than the other, means connecting said passages at their inner ends, and a partition in said steam chamber at the outer ends of the tubes separating said smaller passage from the-inlet ends of said large passage, whereby the second-passage serves as the return. passage for the vapor condensed in the first group.

3. In an apparatus of the class described, the combination of a shell for receiving the liquid to be heated, a heating element therefor of substantially unitary construction comprising a group of tubes extending into the lower portion of said shell, said group of tubesbeing divided into inlet and return passages, said inlet passage being of larger total cross sectional area than said return passage, the outer ends of said tubes being at the exterior of the shell, a tube sheet at the exterior of the shell for receiving the outer ends of said tubes, a divided chamber of dimensions small relative to the sectional area of the shell adjacent said tube sheet and separating the outer ends of the tubes from said respective passages, said divided chamber, tube sheet and tubes being. detachable from said shell, whereby said tube bundle may be withdrawn as a unit and a chamber within the shell connecting said passages at'their inner ends.

In testimony whereof I affix my signature.

' ROBERT JEwET'r PABODIE.

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