US1782585A - Superheater - Google Patents

Description

Nov. 25, 1930. c. u. SAVOYE SUPERHEATER 2 Sheets-Sheet l I Filed Nov. 4, 1924 INVENTOR 4. W

v M 2 ATTORNEYS 0/14 IIIIIIII% I w Nov. 25,1930. c. u. SAVOYE 1,782,535

SUPERHEATER Filed Nov. 4, 1924 2 Sheets-Sheet 2 INVENTOR ATTORN EY Patented Nov. 25, 1930 UNITED STATES PATENT OFFICE CHARLES ULYSSE SAVOYE, 0F HACKENSACK, NEW JERSEY, ASSIGNOR TO THE BAP COCK & WILCOX COMPANY, OF BAYONNE, NEW JERSEY, A CORPORATION OF NEW JERSEY SUPER-HEATER Application filed November 4, 1924. Serial No. 747,708.

My present invention relates to superheaters as usually used with steam boilers, and also to means for regulating the temperature of superheated steam, and will be best understood from the following description and the annexed drawings, in which Fig. 1 is a vertical section of one form of steam boiler having a superheater embodying my invention; Fig. 2 is an enlarged view looking from the left of Fig. 1, with the boiler casing removed and some of the parts broken away, and Fig. 3 is an enlarged view of a portion of Fig. 1.

Like reference characters indicate like parts in the several views. v

In the arrangement illustrated, the boiler has the usual transverse steam and water drum 10, connected by nipples 11 and 12 to the downtake headers 13 and the uptake headers 14, these headers being connected by the water tubes 15 provided with the usual transverse baflies to direct the gases back and forth across the tubes to the gas exit 16. The furnace chamber 17 is fired, in the form illustrated, by an underfeed stoker 18, which extends only partly under the boiler. The particular form of boiler forms no part of my invention, and further description thereof will be unnecessary.

In the form illustrated, I provide an inlet superheater header or box 20 beneath the downtake headers 13, and a similar outlet superheater header or box 21 beneath the uptake headers 14. The inlet header w1ll be connected at its end in the usual manner, with a pipe to lead satui ated steam from the drum 10 to the header 20. The headers 20 and 21 are connected by at least two rows of tubes 22 having their ends expanded into the superheater headers in the usual manner. At least a portion of the tubes are located in proximity to the furnace 17, as illustrated, and are exposed to the radiant heat thereof.

Normally in the operation of the boiler, the saturated steam from the drum 10 will pass to the header 20, and from thence through the tubes 22 to the header 21, and from thence to the point of use, the steam being superheated, in the form illustrated, both by the radiant heat from the fire and also by the hot gases passing across and in contact with the superheater tubes. I

It is desirable to provide means to control the degree of superheat of the steam del vered from the superheater and also, particularly where the superheater is contacted with very hot gases and by the radiant heat from the furnace, to provide means by which the burnirig of the superheater may be prevented. y invention is particularly applicable to a radiant heat, or other, superheater, which is subjected to hi h temperatures, as it provides a means .0 preventing the tubes from overheating through causing heat radiated from the walls of the tubes to be absorbed by a cooler member placed inside of the tubes. Should a hot spot tend to form in the walls of the tubes the radiation would be increased for this particular spot and the metal at this part of the tube would be prevented from reaching a temperature that would cause it to burn. My invention is also useful for preventing the burning of the superheater in starting up a boiler, at which time there may be no steam flowing through the superheater. In the form of construction which I have illustrated, both of these things are attained. In the illustrated form, I provide cooling U-tubes each having straight, parallel legs 23, connected by a bend 24. In each pair of tubes 22 'is one of the legs 23 of one of these U- tubes with the bend 24 in the box 21, the

,box 21 being provided with a large handhole 25 with a cover 26, so that the U-tube 23 may be inserted into and withdrawn from the tubes 22. The legs 23 of the U-tube, in the form illustrated, pass across the box 20 and into nipples 27, expanded into the rear wall of the box 20, the le s 23 having their ends enlarged and fitting or some distance in the nipples 27, with their outer edges rolled over so as to make a tight joint between the left-hand end. of the nipples 27 and these ends of the legs 23. The nipples 27 have their left-hand ends expanded into boxes 28 and 29. The box 28 is connected by a pipe 30 to the steam space in the drum 10, and similarly the box 29 is connected by the pipe'31 to the water space of the drum 10. A valve 32, which, in the form illustrated, is hand-operated by the lever 33 but which may be of any desired type, controls the flow of water through the pipe 31.

By the arrangement described, water from the boiler 10 passes down through the pipe 31, past the valve 32 and into the header 29, and from thence through the U-tubes back to the box 28, and from thence through the pipe 30 to the steam space of the drum 10.

referably, the nipples 27 are arranged so that the legs 23 of the U-tubes are held substantially concentric with the tubes 22.

With the arrangement described, it will be obvious that the steam as it is being superheated is flowing in contact with the legs 23 through which water from the boiler is circulating, the rate of this circulation being controlled in any suitable manner, as by the valve 32. Consequently some of the superheat delivered to the steam will be abstracted therefrom and returned to the boiler through the water circulating in the Utubes, the amount thus abstracted being controlled by the amount of water .flowing through the U-tubes. It will also be noted that even with a constant rate of flow of water through the U-tubes, such water acts to take care of any variations in the superheat, because any increase of superheat in the steam above a given amount will produce a higher heat head between the superheated steam and the water in the U-tubes, and consequently a more rapid rate of flow of the heat to the water in these tubes. Hence, with the valve 32 set for a given operating condition, variations in the rate of firing will be more or less automatically compensated for, so far as the degree of superheat is concerned, by the cooling water in the Utubes.

It will also be obvious that the arrangement which I have described may be used to protect the superheater tubes 22 when the boiler is being started up. At this time, a rapid flow of water through the U-tubes will serve to keep the temperature of the tubes 22 low enough to prevent injury to them until steam from the drum 1O begins to fiow through such tubes in suificient quantity to absorb the heat being delivered to them.

While the arrangement by which the cooling tubes may be passed through the superheater tubes may be widely varied, the arrangement which I have illustrated is particularly effective, since is provides for variations in the amount of expansion of the cooling tubes and the superheater tubes without danger of rupturing the joints, as would be the case if such tubes were each connected to both of the boxes 20 and 21. An expansion of the tubes 22 may move the box 21 to the right of Fig. 3 without disturbing in any manner the connection between the U- tubes and their boxes 28, 29.

While I have shown my invention as ap plied to a superheater, it will be obvious that it may also be used to regulate the superheat in steam flowing from a superheater or in any place where it is desired to regulate the temperature of superheated steam. While I have shown my arrangement as applied to a radiant heat superheater, it is obvious that it may be applied to a superheater heated by hot gases only. It will also be understood that the connection between the legs 23, 23 of the U-tubes may be widely varied and that while the simple bend 24 is illustrated, any other form of connection between these legs may be used and that such connection is intended to be included in the term bend. While I have shown my superheater with horizontal tubes, it will be obvious that my invention is not limited to this particular form. It will also be understood that if the rate of circulation through the cooling tubes is not sutlicient with the arrangement which I have illustrated, such circulation may be accelerated in any desired manner, as by a pump, and, furthermore, it will be understood that the cooling water may be obtained from some source other than the boiler itself.

I claim:

1. In combination, a pair of header boxes spaced apart, a pair of tubes connecting said boxes, a U-tube having its bend located in one of said boxes and each leg extending through one of said pair of tubes toward the other of said boxes, nipples expanded in the other of said boxes, the end of each of said legs extending across said other box and through one of said nipples with its edge rolled over the end of said nipple.

2. A steam boiler, a superheater having in let and outlet boxes spaced apart and connected by superheater tubes, the wall of one of said boxes opposite the superheater tube connections being provided with openings registering with said superheater tubes, water boxes at the rear of the last mentioned box provided with openings registering with those of said superheater box, nipples secured in the openingsof said superheater box and the openings of said water boxes, and a U-shaped water cooling tube having its ends Secured in said nipples and having its bent end located in the other superheater box.

3. A seam boiler, a furnace therefor, a superheater having a portion thereof located in proximity to said furnace and having its tubes directly exposed to the radiant heat of the furnace and a water-cooled core in each of said tubes.

4. A steam boiler, a furnace therefor, a superheater having a portion thereof located in proximity to said furnace and having its tubes directly exposed to the radiant heat of the furnace, and a water-cooled core in each of said tubes and connected to the steam and water spaces of the boiler, whereby boiler water may be circulated through said cores.

5. A steam boiler, a furnace therefor, a superheater having tubes exposed to the radiant heat of the furnace and located wherethe gases from the furnace engage the superheater before engaging boiler heating surface, and a water-cooled core in each of said tubes and connected to the steam-and water space of the boiler, whereby boiler water may be circulated through said cores.

6. In combination, a steam boiler having boiler heating surface, a furnace therefor, a superheater comprising tubes, a water-cooled core in'each of said tubes and connected to the steam and water spaces of the boiler, and means for passing all the furnace gases over said tubes before passing over the boiler heating surface.

7. In combination, a steam boiler, a furnace therefor, a superheater having a portion thereof located; in proximity to said furnace and having its tubes directly exposed to the radiant heat of the furnace, a water-cooled core in each of said tubes and connected to the steam and Water spaces of the boiler, and means for passing all of the furnace gases over said tubes before passing over the boiler heating surface.

8. In a steam boiler, a furnace therefor, a superheater having a plurality of tubes, one portion of said tubes being directly exposed to the radiant heat of said furnace, each of said portions being provided with a Watercooled core.

9. In a steam boiler, a pair of superheater boxes spaced apart,'a pair of tubes connecting said boxes and directly exposed to the radiant heat of the furnace, anda pair of water tubes connected into the boiler circulation passing through the respective superheater tubes, said water tubes being connected together in one of said boxes and passing through the other box.

10. In a steam boiler, a pair of superheater boxes spaced apart, a pair of tubes connecting said boxes and directly exposed to the radiant heat of the furnace, a pair of headers located adjacent to'one of said boxes and connected thereto by a pair of nipples, and a pair of watertubes passing through said superheater tubes and through the nipples connected between the headers and box and communicating with the respective headers.

CHARLES ULYSSE SAVOYE.

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