US2079104A - Superheater - Google Patents

Description

I May 4, 1937. c. A. BRANDT a r 2,079,104

SUPERHEATER Filed Jan. so, 1956 2 sheets shegt 1 INVENTOR CARL A. BRA/var ATTORNEY May 4, 1937.

c. A. BRANDT YSVUPERHEATER 2 Sheets-Sheet 2 INVENTC JR CARL A. BRA/V07. BY

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Filed Jan. 30, 1936 ATTORNEY Patented May 4, 1937 2,079,104

SUPERHEATER Carl A. Brandt, Great Neck, N. Y., assigiior to The Superheater Company, New York, N. Y. Application January 30, 1936, Serial No. 61,495

. 8 Claims. (Cl. 122-462) This invention relates to superheaters and heaters shown in Fig. 1; Fig. 3 is a section on line more particularly to structures of this kind which 3-3 of Fig. 212; Fig. 4 is a view similar to that of a e p to gases of high t mpe ature fo Fig. 1 showing, however, only a single flue with S P o s f h p a r and a es of another type of superheater element located 5 o er t pe a u for her portions. A situtherein; Figs. 5a and 5b are respectively sections 5 ation of this sort is found in the case of locomo-. n lines 5a 5a and 5b-5b of Fig, 4. Fig. 6 is tive superheaters ad 1 p of tubular elements a somewhat diagrammatic side elevational view located in the flues. The gases from the fireof a superheater of another type; Fig. 7 is a view be passing through the in s ar of a Very hi h of a single unit of such a superheater, the sec- 10 temperature when they first strike the supertion being taken on line 1-! of Fig. 6. 10

. heater a d a e pro ressively cooler as they flow The superheater element or unit represented o d the front e There has been a Steady in Fig. 1 is of the kind made up of a plurality of trend toward high a d higher perheated loops l--l each of which extends into one of the steam temperatures not only in connection with flues 2-2, In this type there is usually only one i5 locomotives but in general superheater use. In loop in each flue lt t arrangement may th c se of a locomotive higher steam emper be such that each flue may contain more than tures could probably e o n d f r gases one loop, the loops in any single flue, however, were forced through the fines. As it is,. those belonging t different units, The ends of the portions of the superheater which lie in the cooler h ater units are connected to a header 3 2 as zones are not wo ked anyw ne'er to the with an inlet chamber 4 and an outlet chamber limit of their capacity so that the structure is 6. Gases enter the flues l--l at the left, as financially uneconomical. Could the temperavi d i th fi and leave at the right. ture of the gas e raised, s o exa ple by If in such an arrangement sufiicient gases are towi e gases through the nes, the result forced through the fiues to result in a' desired would be improved from economical Point Of high final steam temperature, the portions in 25 view. Howeve t e p t o which a e nearest the vicinity of the entrance end of the gases will to the gas entrance would then be sub ect t be exposed to extremely severe conditions. The peratures which they could not resist unless these gas temperature t thi d i very hi h a d th portions of h SU-Derheater elements were made metal temperature will be raised to an inadmis-, of heat resistant alley steels, which would in sibly high point. The difliculty here is not to get 30. turn introduce a fa or f xp the heat into the metal from the gas, but to carry It is the obJect of the present invention to proit away from the metal quickly enough by means vide supe hea e s, especially of the locomotive of the steam to protect the metallic wall. If type just referred to, which will allow high supermeans could be provided here t enhance t heated steam temperatures and yet will not have rate of heat tr n fer into the steam, then t 35 a y of their portions p s d to Such conditions gas temperature might be allowed to be considert the element would endangered or that ably higher than is admissible in superheaters as special steelswould be required. built heretofore, y In t r ader aspects ltlhe invention is not On the other hand as the outlet ends of the l limited to locomotive super eaters bu has appli- 40 cation also to types of superheaters such as used 233 figy ggg igk gi gg t g 1 of by over the superheater elements in a direction genaway at hlgh rate the dehvered to suqh erally transverse to the tubular portions of the W by gafses but to Increase the rate at 45 superheater. which heat is given up by the gases to the me- The invention will readily be understood from tamc a the following description which makes reference I satlsfy the fi named sltuatlon by meats to the annexed drawings Fig 1 f these drawillustrated in Fig. 2c. The tubular element I is ings is a more or less diagrammatic longitudinau here shown in section and it will be noted that 50 sectional view of one type of locomotive superon the inside there is placed in each branch heater together with the flues in which the eleof the loop a Sp a a d ThiS Spiral a d .ments are located. Figs. 2a and 2b are respeccauses a rotary movement of the steam in additively enlarged lateral views partly in section of tion to the linear movement and this causes a certain portions of one of the loops of the supermuch higher rate of transfer from the Walls to 55 -in. the vicinity of the gas the steam than that obtained with the ordinary unit without such provision.

At the forward end I meet the conditions by securing to the outside of the elements longitudinally extending fins 10-40. See Fig. 2b. These fins increase the rate of heat absorption by the tubes from the gases and so increase the temperature of the walls and hence the transfer from the walls to the steam. As will be seen from Fig. 3, the number of fins is rather optional. One of the branches is shown as provided with three fins whereas the other one is shown with only two. Any desired number of fins may be used and within the scope of my invention the same number may be applied to all the branches or different numbers to different branches.

The outside of that portion of the element which has means on the inside to promote the heat transfer from the metal to the steam is left bare, that is, it is not provided with any means for increasing the rate of heat transfer from the gases to the metal. Similarly the inside of that portion which has means on the outside for enhancing the heat transfer rate is left bare, that is unprovided with any means for increasing the heat transfer means from the metal to the steam.

The flue shown in Figs. 2a and 2?) may be any one of the fiues of Fig. 1, the arrangement in all of them being similar.

By the means described a much higher final superheated steam temperature is obtained than with the ordinary unitand this is 'done without in any way endangering any portions of the superheater unit by excessive metal temperatures.

For a certain length of the'unit between the portions near the entrance of the gases and the portions near their rate of heat transfer into and from the metal will be such that either no increase on either side is made or means for thesame increase on both sides are provided, the transfer being well balanced over this part of the unit. In the form shown no means are shown either on the inside or on the outside for enhancing the heat transfer.

In Figs. 4; 5a and 5b is illustrated a locomoltive superheater element of a different type. In this case there are two loops in the flue 2a, both loops belonging to the same superheater element. The invention applies equally well to this case. As seen in Fig. 5a internal means are provided for enhancing the rate of heat transfer from the element wall to the steam in those portions inlet. In this instance instead of these means taking the form of a spiral as in the case first described, they are here given the form of internal fins extending inwardly from the walls. These fins assist the transfer of the heat from the walls into the steam and perform the same function therefore as the spiral band in the form first described.

At the end of the unit adjacent to the gas outlet of the fiues fins are secured to the outside of the tubes assisting gases into the tube wall.

This unit will accomplish the the one first described will make it possible same thing that accomplishes, namely it to deliver steam with a higher temperature than is possible with the ordinary unit without thereby endangering the unit at any point by excessive metal temperatures.

The use of the inventive idea is as stated above not limited to locomotive superheater elements, but may be extended to superheaters in s a ionexit, conditions for proper the heat transfer from the ary boilers as well as to separately fired superheaters. An installation of this type is illustrated in Figs. 6 and 7. The heating gases in Fig. 6 flow in an upward direction through the passage defined by the two walls l2l2. Evidently the lowerportions of the superheater will be exposed to a higher temperature than those nearer the top. The latter portions are ordinarily not worked up to capacity because to do so would endanger the ones nearer the bottom. In accordance with my invention I enhance the rate of heat transfer from the wall of the element to the steam in those portions adjacent to the gas inlets and enhance the rate of heat transfer from the gases to the element wall for those portions adjacent to the outlet. In the form shown in Fig. '7 the means to accomplish the first of these ends takes the form of fins 812-812. The means to increase the heat transfer from the gases to the element in the cooler zones are external fins 10b.

In this form of the inventiona furth'er idea is illustrated, namely that the means to -aid the heat transfer may be varied so 'a's' to result in greater effect in one portion than in=another.

For example, the internal fins inthe lowest; two tube lengths are three in number whereas those in the next two tubes are two in number. This illustrates that the increase of transfer from wall to steam may be made greater as the -hottest zone is approached; p' a i Similarly, the rate. of heat transfer from the gases to the walls of the element may be progressively increased as the cooler zone is approached. This is illustrated by the fact that the third tube from the top in Fig. '7 has two fins, the second one from the top three,'and.the topmost one our.

A similar progressive increase'can be secured in the case of the locomotive units by varying the number or size of the fins as the hotter or cooler zone is approached.

In practicing this invention -no doubt variations from the precise forms will occur.- -As long as they are within the spiritof the invention Q the following claims are intended to include such variations.

What I claim is: Y 1. In a steam superheater of the type comprising tubular elements through which the steam hance the rate of transfer of heat from the metal to the steam, the outside of the tubes of these portions being bare'and means on the outside of the second named portions to enhance the rate of transfer of heat from the gases to the metal, the inside of the tubes of these portions being bare.

2. In a steam superheater of the type comprising tubular elements through which the steam flows and which are exposed to heating gases of progressively higher temperatures from one end of the superheater to the other, the combine.-

tion of such a superheater with means within those superheater portions exposed to the hotter gases to enhance the rate of heat transfer from the metal to the steam, said means being such and being so arranged that their effect progressively increases as the zone of highest gas temperature is approached, and means on the outside of those portions exposed to the cooler gases to enhance the heat-transfer from the gases to the metal, these last-named means being such and so arranged that their effect progressively increases as the zone of lowest gas temperature is approached.

3. In a steam superheater of the type comprising tubular elements located in lines through which the heating gases flow, the combination with such tubular elements of means within,

those portions of the elements toward the end where the gases enter the fiues to enhance the rate of transfer of heat from the'metal to the steam, the outside of the tubes of these portions being bare and ofimeans onthe outside of those portions of the elements toward the end where the gases leave thefiues to enhance the rate of transfer of heat from the gases to the metal, the

inside of the tubes of these portions beingibare;

4. Apparatus-in accordance with claim 3, at least one of said means being fins.

5. Apparatus in accordance with claim 3, the first-named means being spiral bands.

6. Apparatus in accordance with claim 3,---both of said means being fins sec-ured to th e tube walls.

7. Apparatus in accordance with claim 3, the

first-named means being spiral bands, and the second named means being fins. 8. Apparatus in accordance with claim 3, the

first-named means being such as to give a rotary movement to the steam, and the second-named means being fins parallel to the axis of the tube.

1 CARL A. BRANDT.

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