US1796662A - Heat exchanger - Google Patents

Description

F. W. OFELDT HEAT EXCHANGER Filed Aug. 26; 1927 March 17, 1933.

I 2 Sheets-Sheet l IT 20 5 v 20 3 11 6 INVINTO R F. W. OF ELDT HEAT EXCHANGER Filed Aug. 26,

. March 17, 192.1.

1927 2 Sheets-Sheet 2 Patented Mar. 17, 1931 UNITED STATES FRANK W. OFELDT, 6F MOKEESPORT, PENNSYLVANIA HEAT nxcinlvenn Application filed August 28, 1927- Serial No. 215,558.

. as water boilers, steam boilers, and the like,

and more particularly to a heat exchanger ,8 of the coil type, particularly adapted for the heating of water.

It has heretofore been proposed in the art .to which the present invention relates to provide coil or tube heaters of the general character herein contemplated and com-. prising a main source of water supply communicating with a plurality of tubes or coils dis osed in a suitable heating chamber. In such apparatus, there has, however, been no means for securing eflicient distribution of the liquid through the coils or tubes, or for obtaining efficient circulation of the heated water throughout the entire system.

The present invention has for one of its objects the provision of an apparatus of this character so constructed that the liquid is efl'ectively caused to pass in divided or distributed condition through the heating coils or tubes provided for that purpose.

Still another object of the invention is to provide a construction such that in a predetermined portion or portions of the apparatus the water is raised to a steam generating temperature while the water in the other portions of the apparatus is being heated, the steam thus. generated being utilized to produce a forced circulation throughout the heating system with which the heat exchanger is utilized.

In the accompanying drawings there are shown for purposes of illustration only, certain preferred embodiments of the present invention, it being understood that the drawings do not define the limits of my invention as changes in the construction and operation disclosed therein may be made with out departing either from the spirit of the invention of the scope'or my broader claims.

In the drawings,

Fig. 1 is a vertical sectional view with certain of the parts in elevation,- through one form ofheat exchanger constructed in accordance with the present invention};

' Fig. 2 is a transverse sectional view on the line 11-11 looking in the direction of the arrows; Fig. 3 is a view similar to Fig. 1 showing a slightly modified embodiment of the present invention; and, I

Fig. 4 is a detail sectional view on an enlarged scale of the safety lighter.

In carrying out the present invention, there may be provided a suitable casing 2 mounted on a base 3 and communicating: at its upper portion with a suitable outlet 4 for the escape of products of combustion.

-Extending centrally within the casing 2 is a tubular water receiving casing 5 communicating at its lower end with a supply connection 6through which the water to be heated is en plied to the apparatus. At its upper end t e casing 5 communicates with a water outlet 7 leading to the part of the system to which hot water is to be supplied. At a suitable point intermediate the connection 6 and the connection 7, the casing is provided with a baiile plate 8 having a restricted orifice 9 therein for the purpose hereinafter more fully pointed out.

Arranged within the heating compartment formed between the casings 2 and 5 is a plurality of tubes or coils 10 of suitable construction, each of the tubes or coils preferably communicating at one end with the casing 5 adjacent the oint of water inlet thereto at one side of t e baiile 8 and at the other end with the casing 5 adjacent the point of water outlet therefrom, and above the baflle 8.

One or more of these pipes or coils is of such construction that it provides a greater, heating surface per unit of water than the other coils or pipes, whereby with a constant heat transfer coefficient, the total heat transfer to the water passing therethrough is greater than the total heat transfer to the water passing through the other pipes or coils. This condition may be effectively obtained either with an arrangement such as illustrated in Fig. 1 by the utilization of a coil 11 having a greater over-all length than the other coils, or as indicated by Fig. 3by the provision of a coil 11, having a restriction in the inlet thereof causing a less amount of water to flow through it under given conditions than passes through the other heat transfer units.

With either formof the'apparatus, the parts are correlated and arranged in such manner that in passing through the transfer unit 11 or 11, the water is raised to such a temperature that steam is generated, this steam being relieved through a nozzle '12 directed upwardly into the outlet connection 7 in the general direction of flow there-.

through. This generated steam passing into the body of water acts to produce in effect, an aerated column, the steam bubbles decreasing the effective weight of the liquld per unit of pipe length whereby it tends to rise and thus produce circulation in the system.

' gas supply line 17 The supply of gas maybe automatically or manually controlled, there being illustrated in the drawings, a heat responsive element 18 adapted to operate a valve 19 to admit more or less gas depending upon the temperature of-the water leaving the heater.

Arranged within the heating chamber and carried by the burner plate 3 is a ser es of distributors 20, each cooperating at its inner end with one of the openings 13, and

suitably held on the burner plate in any desired manner as by fastenin bolts 21. Each of these distributors is 0 such construction as to effectively break up and mstribute the gas supplied thereto from the nozzle 15, together with entrained a r, th1s being accomplished in the form lllustrated by the provision of transverse slits 22.

There may be provided a safetylightlng device, comprising a movable pilot tube 23 having its lower end constructed to form a valve 24 operative in the gas supply hne 17 The upper end 25 of the safety llghter 23 is directed inwardly and is adapted to extend into and through a nipple 26 on the side of the casing 2. It carrles at a suitable point intermediate its length a closure plate 27 adapted to completely'tclose the outer end of .the nipple 26, which ple constitutes the only means of access or hght ng purposes to the interior of the heater. In operation, the safety hghter 23 1s swung to the right as viewed in Fig. 4, and thegas issuing from its upper end is lighted. It i is then swung into the position indicated in dotted lines in this figure, this movement being efiective for opening the supply line 17 for the free passage of gas therethrough, which gas as it issues from the distributors, is lighted within the heater. Should the operator fail to light the safety pilot before swinging it into position, there is .no means of igniting the gas within the heater and consequently the possibility of an explosion is obviated. In order to light it, it is nec-- essary to swing the safety valve out of its dotted line position, which shuts off the gas to the nozzle 15, and manipulate the parts through a new cycle as before described.

The construction illustrated in Fig. 3 corresponds to that shown in Fig. 1 with the results in the generation of steam for the purposes referred to.

The ba'flie 8 serves a dual function in the construction illustrated, in that it prevents free flow of water from the inlet 6 to the outlet 7 thereby compelling passage of water through the heating units, and further in that it permits a limited circulation directly between the inlet and outlet which limited circulation is sufiicient to adequately take care of the heat transfer through the surface provided by the casing 5 and thereby precludlng theformation of a steam pocket therein.

Certain advantages of the present invention arise from the provision of an improved heat exchanging apparatus providing means for the heating of water in distributed condition while insuring thegeneration in limited quantities of steam for circulation pur-' poses while precluding the generation of steam in all of the uni Still further advantages of the invention arise from,the provision of a water heating boiler comprising a series of units, the heater being provided with means insuring the passage of water through these units.

Still other advantages of the invention arise from the revision of means for efiectively distributmgthe combustible mixture to thereby obtain efiicient flame conditions within the heater. I 4 1 Still other advantages arise from the provision of safety means for lighting the heater.

I claim: I I

1. Ina water heater, 9. central water sup-. ply-casmg"hav1ng a bafile therein, an outer casing, a. plurality of water heating units .thepassage of only a each unit having its central casing at one its outlet connected between said casing, inlet connected to said side of said baflle and to said central casing at the opposite side of said baflle, at least one of said units being constructed toinsure a greater total heat transfer for a given quantity of. water than the other units,' and means for heating said units. L

2. In a water heater, a' central water suppuly casing having a bafile therein, said baffle having an opening of such size as to allow limited quantity of outer casing, a pluunits between said water therethrough, an rality of water heating casings, each unit having its inlet connected to said central casing at one side of said baifle and its outlet connected to said centralcasing at the opposite side of said bafile, at least one of said units being longer than the others so as to generate steam therein eflectlve for causing circulation of water in said other un1ts, and means for heating sald units.

Intestimony whereof I have hereunto set my hand.

FRANK W. OFELDT.

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