US1834782A - Superheater - Google Patents

Description

Dec. 1, 1931. D. s. JACOBUS 1,834,782

SUPERHEATER Filed F'eb. 17, 1922 4 Sheets-Sheet l N VEN TOR.

JV Z j/ zp @bu ATTORNEYS.

Dec. 1, 1931. 5 JACQBUS 1,834,782

SUPERHEATER Filed Feb. 17, 1922 4 Sheets-Sheet 2 F LS I ENTOR.

ATTORNEYS.

Dec. 1, 1931. s, JACOBUS 1,834,782

SUPERHEATER Filed Feb. 17, 1922 4 Sheets-Sheet 4 l v J 7- i I 1 IN; 'EN TOR.

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ATTORNEYS.

Patented Dec. l, 1931 UNITED STATES HPATENT OFFICE DAVID s. JAcoisUs, oE JEnsEY 01m, NEW JERSEY, ASSIGNOR TO THE BABCOOK a WIL- cox COMPANY, or BAYONNE, NEw JERSEY, a CORPORATION or NEw JERSEY SUPERHEATER Application filed February 17, 1922. Serial No. 537,153.

My invention relates to improvements is superheaters, particularly those in which on the line 22 of Fig. 1; Fig. 3 is a section" on the line 33 of Fig. 1; Fig. 4 is an end view of a portion of the superheater; Fig. 5 is a section of the boiler taken on the line 55 of Fig. 7; Fig. 6 is a plan view of Fig. 5, with a partial section taken on the line 6-6 of Fig. 5, and Fig. 7 is a section on the line 7-7 of Fig. 6.

Like reference characters indicate like parts in the several views.

In the illustrative embodiment of my in vention shown in the drawings, there is a common setting 10 divided by a longitudinal wall 11 so as to form what is, in effect, a pair of parallel flues or gas passages. In the form illustrated, the furnace chambers 12 and 13 are fired by oil burners located at the left of Figs. 1 and 5, respectively, but, if debe formed into a single chamber by stopping off the portion 111 of the dividing wall 11 before it reaches the left-hand end wall of the setting.

The boiler may be of any suitable form, and asillustrated consists of a lower water drum 14 (Fig. 5) and an'upper steam, and water drum 15 connected by vertical tubes A 16 and divided by vertical baflies, the gases passing over the tubes 16 in a direction generally longitudinally of the drums.

The superheater in the form illustrated is made up of two connected sections, the first section having a plurality of cross headers 20 located at the lower part and over the setting and U-tubes 21 extending upwardly therefrom and arranged to connect the headers 20 serially, so that steam from the drum 15 passing through the pipe 22 will enter the header 20 at the right of Fig. 1, and from thence will flow through the tubes 21 successively toward the left of Fig. 1. The baflies 23 and 24 are provided to cause the gases from the furnace chamber 12 to flow up and down along the tubes 21. Between the furnace chamber and the tubes 21 is a high bridge wall 25 arranged to form a vertical portion to the flue in which the superheater is located and over which the gases flow before contactin with the tubes 21'.

The part of the superheater which comes nearest the fire comprises a special element especially designed to resist high temperatures. This'special .element is made up of a superheater inlet header 26 and an outlet header 27, the header 26 being connected to the left-hand header 20 of Fig. 1 by a p e 28. The headers 6 and 27 are connected by super-heater tub 8129 which are doubled back and forth, as shown best in Fig. 2, and which preferably are divided into series, so that the steam entering the header 26 will flow through some of these tubes to the header 27 and from' thence through others of these tubes back to the header 26 and from thence through the remainder of the tubes back to the header 27' at a higher velocity than it flows through the tulfies in the main body of the superheater, and from thence out to the point of use. This high velocity of flow and the counterfiow to the gases from the furnace chamber may be provided for by diaphragms 30 and 31 located respectively in the headers 26 and 27, as best shown in Fig. 4.

The dividing wall 11, in the form illustrated; is provided with a gas exit 32 in the position shown in Figs. 1 and 5, so that the gases, after flowing over the superheater tubes 21, may pass laterally through the wall 11 into the last vertical gas pass of the boiler to join the gases used to heat the boiler,

and pass out therewith, through the exit for the boiler. The opening 32 may be provided with dampers y which its area may be event that this section is burned out, or injured, it may be readily removed and replaced without disturbing the other section of the superheater.

-Moreover, as it isdesirable to have the steam flow through this portion nearestthe furnace at" a ver high velocity, I have provided a steam ow area through the tubes 99 thereof which is much smaller than the steam flow area through the tubes 21. In the ar ticular construction illustrated, it wil be seen that the steam from the header 26 flows to the header 27 through three of the superheater tubes only, whereas the steam from each of the headers 20 flows to the next ad- 'acent header through many times this numer of tubes. Moreover, the first pass of the steam between the headers 26 and 27 is through three tubes 29, whereas the remaining asses between the headers 26 and 27 are t rough two tubes,only. Consequently,

the steam which has been highly heated in the tubes 21 will pass through the tubes 29 at a very great increased velocity which in itself serves to prevent the tubes from local overheating and from one of the tubes being heateater extent than the others and ed to a wlthout lncreasing the total frictional reslstance of the flow of steam through the superheater to a prohibitive extent. The

first section .of thesuperheater thus comprises a plurality of sets of tubes, at least a portion of the tubes of one set being ex- 5 posed to the radiant heat of the furnace.

The special element which comes nearest the fire is arranged so that the part of the tubes swept over by the hot gases can be readily treated to make it more resistant to deterioration at a high temperature by caloriZing without treating the ends ofthe tubes WhlCh are expanded into the headers. The ends of the tubes which are expanded into the headers are protected from external heat and are not at as high a temperature as the parts of the tubes which are swept over by the hot gases. This is on account of the fact that the parts of the tubes swept over by the hot gases are at an intermediate temperature 50 between that of the hot gases and the steam which is circulated through the tubes,'whereas the ends of the tubes which enter the headers, which are protected from tli e-jhot gases, are at a temperature approachi that of theiise'am flowing through them. calcan be protected ronr the hot gases. The

tubes of the superheater which are subjected to the highest temperature are, therefore, composed of material differing from that of the tubes subjected to a lower temperature and better adapted to withstand high tem peratures effectively than the material of which the lower temperature tubes are formed.

In some cases the division wall 11 between the elements 12 and 13 may be omitted and when this is done, it is important that the special element be arranged so that it can be flooded with water to protect it during the starting up period when no steam is flowing through the superheater.

In starting up the boiler and superheater when the divisional wall 11 is used, the fire is lighted in the furnace chamber 13 and the hot gases pass over the boiler tubes. No fire is lighted in the furnace chamber 12 until the steam is flowing through the superheater to a sufiicient amount to protect the superheater from overheating on starting the fire in the furnace chamber 12.

In starting up the boiler and superheater it'll when the portion 111 of the dividing wall 11 is omitted, the special section of the superheater would be ordinarily flooded with water and the damper in the opening 32 would be closed to prevent a flow of the hot gases over the superheating surface. After steam has been generated in the. boiler, the water would be blown out of the special element through a suitable drain and steam caused to circulate through the superheater. After this, the damper in the opening 32 would be opened and the hot gases allowed to flow overthe superheater.

It will be obvious that the arrangement which I have described may be varied within wide limits. It will be obvious, for instance,

that the two separate sections ofthe superheater may have any suitable arrangement other thanthat illustrated, and that while the boiler with the drums extending longitudinally of the setting provides an arrangement which is compact, any other form of boiler may be used instead.

I claim v V 1. A furnace and a flue leading therefrom to a gas outlet and a superheater in said flue, said superheater bein divided into two sections connected in serles and arranged to be steam to flow back and forth between the headers, the flow area for the steam of the section nearest the furnace being less than that of the section farthest from the furnace.

2. A furnace and a'flue leading therefrom to a gas outlet anda superheater in said flue,

said superheater being divided into two sections connected in series and arranged to be contacted serially by the hot gases from the furnace, the section farthest from the furnace comprising headers extending transversely to the direction of flow of the heating gases and tubes connecting said headers serially, and the section nearest the furnace comprising headers protected from the hot gases and tubes directly exposed to hot gases and extending across the flue with the headers and tubes arranged to cause the steam to flow back and forth between the headers in a direction generally counter to the flow of the hot .gases, the flow area for the steam of the section nearest/the furnace being less than that of the section farthest from the furnace. p

3. A furnace and a flue leading therefrom to a gas outlet and a superheater in said flue,

said superheater being divided into two sections connected in series and arranged to be contacted serially by the hot gases from the furnace, the section farthest from the furnace comprising headers extending trans verselyto the direction of flow of the heating gases and tubes connecting said headers serially andbaflies to direct the gases along the tubes in a direction generally counter to the flow of the steam, and the section nearest the furnace comprising headers protected from the hot gases and tubes directly exposed to hot gases and extending across the flue with the headers and tubes arranged to cause the steam to flow back and fortlf between the headers in a direction generall counter to the flow of the hot gases, the ow area for the steam ofthe section nearest the furnace being less than that of the section farthest from the furnace.

4. A furnace and a flue leading therefrom to a gas outlet and a superheater in said flue,

said superheater being divided into two sections connected in series'and arranged to be contacted-serially by thehot gases .from the furnace, the section farthest from the furnace comprising headers extendin' gtransversely to the direction of flow of the heating gases and tubes connecting said headers ,comprlsing headers on opposite sides of the flue and tubes directly ex osed to hot gases and extending across the ue with the headers and tubes arranged to cause the steam to flow back and forth between the headers, the steam flowv area in the section nearest the furnace being smaller than the steam flow area of the section farthest from the furnace and the steam flowing from the section farthest from the furnace into the section nearest the furnace.

5. A furnace and a flue leading therefrom to a gas outlet anda superheater in said flue, said superheaterbeing divided into two sections connected in series and arranged to be contacted serially by the hot gases'from the furnace, the section farthest from the furnace comprising headers extending transversely to the dlrection of flow of the heating gases and a series of U-tubes connecting said headers serially, and the section nearest the furnace comprising horizontal tubes directly exposed to hot gases and extending across the flue, the flow area for the steam of the section nearestcthe furnace being less than that of the section farthest from the furnace. f

6. A furnace and a flue leading therefrom to a gas outlet and a superheater in said flue, said superheater being divided into two sectionsconnected in series and arranged to be contactedserially by the hot gases from the furnace, the section farthest from the furnace comprisin headers extending transversely to the direction offlow of the heating gases and a series of U-tubes connecting said headers serially, and the section nearest the furnace comprising horizontal tubes directly exposed to hot gases and extending across the flue and connected to cause the steam to flow in a direction generally counter to the flow of the hot gases, the steamflow area in the section nearest the furnace being smaller than the steam flow area of the section farthest from the furnace and the steam flowing from the section farthest from: the furnace into the section nearest the furnace.

7. In an independently fired superheater, a sour ce of heat, a flue leading therefrom, a superheater having a plurality of connected sections arranged in tandem in the heating flue, each section having a metallic tubular heating surface directly exposed to hot gases and each section havinga pluralit back-and-forth asses, the general direction of the steam in t e sections being in counterflow relative to the flow of gases thereover, and connections arranged to supply steam to the rear portion of the rear section and to take superheated steam from the forward ortion of the front section, the flow of gases ing transversely of the tubes of the front section and longitudinally of the tubes of the rear section.

8. A furnace and a superheater divided into two sections, the first of which comprises a plurality of sets, at least a portion of the tubes of one of the sets of the first section being exposed to the radiant heat of the furnace and serving as a radiant heat screen for the second section, the gases passing between and around the tubes of the first section, the flow area for the steam through the first section being less than that through the second section, and the flow area for the steam through the tubes of that set of the first section having tubes exposed to the radiant heat of the furnace being less than that for another set of tubes of said first section.

DAVID S. JACOBUS.

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