US2152340A - Superheater boiler - Google Patents

Description

March 28, 1939.

W. H. ARMACO$T SUPERHEATER BOILER Filed Jan. 24, 1935 2 Sheets-Sheet INVENTOR BY a I ATTORNEY March 28, 1939-.

w. H. ARMACOST SUPERHEATER BOILER Filed Jan. 24, 1953 2 Sheets-Sheet ATTORNEY Patented Mar. 28, 1939 UNITED STATES PATENT orrics SUPERHEATER BOILER Application January 24, 1933, Serial No. 653,254

3 Claims.

My invention relates to a superheater boiler.

and particularly to one having novel means whereby the final steam temperature at a given load may be adjusted as desired within considerable limits.

In order that my invention, together with its objects and advantages, may be fully and readily understood, I will now describe in detail and in connection with the accompanying drawings two forms of superheater boiler selected by way of example from a number of possible embodiments of my invention. In the drawings:

Fig. 1 is a vertical sectional elevation through a straight tube water tube superheater boiler of the interdeck type.

Fig. 2 is a fragmentary section on line X-X of Fig. 1 and illustrating the elements of the superheater positioned in conventional spaced relations which are adapted to produce the maximum superheat.

Fig. 3 is a section similar to Fig. 2 but illustrating the elements of the superheater in a different relative position.

Fig. 4 is a section similar to Fig. 2 but illustrating still another relative position of the superheater elements.

Fig. 5 is an elevational view of a longitudinal drum straight tube water tube superheater boiler. Fig. 6 is a section on the line 66 of Fig. 5.

Fig. '7 is a fragmentary elevation of a portion of Fig. 5 illustrating the superheater units in a different relative position from that of Fig. 5.

Fig. 8 is a fragmentary elevation similar to Fig. 7 but illustrating the superheater units in still 353 another relative position.

Fig. 9 is a fragmentary detail of a portion of a superheater header illustrating on a large scale the joints and holding means for one end of a pair of superheater units.

In the arrangement illustrated in Fig. 1, ll! is a cross drum of a horizontal water tube boiler having slag screen bank composed of tubes I2, l2 and a main generating bank composed of tubes l4, M. The main generating bank is separated from the slag screen bank by a space IS. The tubes 12 and M are connected to the drum ID in a well-known manner to provide a thermal circulation through the tubes and drum when the tubes are heated. A superheater composed of units, one of which is shown at I8, is arranged in the space l6. Ordinarily, the units of a superheater in a space such as It are arranged in equidistant parallel planes. Such an arrangement is illustrated in Fig. 2. When the units l8 of a superheater are arranged as shown in Fig. 2,

the maximum superheat is obtained at a given load for a given installation. If, however, the steam delivered from the superheater is at too high a temperature under such conditions, I find that the temperature can be reduced by changing the relative position of the individual tubes of the units in a way to reduce their efiective heating surfaces. Such a relative position of the tubes is shown in Fig. 3 in which the effective heating surface is considerably reduced by springing the adjacent tubes so that one touches another and thereby prevents the gases from passing over one side of each tube, the tubes then being in pairs and only the outer sides of each pair being active. I do not limit myself to any particular means for holding the "units in a desired position. However, in the arrangement illustrated, the units l8 are suspended from the generating tubes M by Christmas trees each of which is composed of a central hanger rod 20 and a plurality of horizontal arms 22 on each side of the rod 29. The arms 22 have sockets 24 in their upper faces into which the elements or tubes of the units fit and which thereby determine the distance between adjacent tubes. When it is desired to alter the relative spacing of the tubes from that shown in Fig. 2 to that shown in Fig. 3 or Fig. 4 it is necessary only to change the type of Christmas trees employed. In Fig. 3, the hanger rods 20 of the Christmas trees have arms 22A thereon which are of greater length than the arms 22 and which have the sockets 24A, 24A farther from the center lines of the rods 20 than is the case with the sockets 24 in arms 22. Therefore, when the elements of units l8 are placed in sockets 24A, the elements are held together in pairs so that the gases can pass between the elements of a given pair only with difiiculty, if at all, thereby reducing the effective surface of the units. In the arrangement shown in Fig. 4:, the rods 20 of the Christmas trees are shown as having arms 22A fixed to their upper portions and arms 22 fixed to their lower portions so that the effective surface of the arrangement shown in Fig. 4 is intermediate those of the arrangements shown in Figs. 2 and 3. In Fig. 4, the three lower rows of elements of the superheater are equally spaced in the horizontal direction and the upper rows are grouped together in pairs. The reverse arrangement may, of course, be used whenever desired, and neither do I limit myself as to the number of rows which may be grouped in one arrangement or the other. While the units [8 of the arrangement shown in Fig. 1 are assumed to be firmly connected to headers 26, 26 by ordinary rolled joints, it will be understood that the serpentine units I 8 of the type illustrated are sufiiciently resilient to permit them to be sprung one way or another to the extent indicated in Figs. 3 and 4.

In the arrangement illustrated in Fig. 5, the boiler is of the longitudinal drum type having a generating bank composed of tubes 30, 30 and a superheater composed of a number of U-shaped units 32, 32 which hang insubstantially vertical planes and envelope the generating bank formed of tubes 30 on three sides; units 32 extending from one header 34 down along one side of the generating bank, across thebottom of such bank and then up along the other vertical side of the bank to the other header. Preferably the mid points of the central bridge portions of the U- shaped units 32 are supported from the lower row of tubes 30 by means of U-bolts 34, 34 and bar 36. However, I do not limit myself to this.

As appears more clearly in Fig. 9, units 32 are connected to headers 34 by means of ball and socket joints which permit the ends of the units to rock through material angles without danger of leakage at their points of connection to the headers. As shown in Fig. 9 also, the ends of the "tirely in the central bridge portions-of the units units are held firmly against their sockets when in use by clamping means 38 of a known type.

It will be seen from Figs. 5 and 6 that the effective surface of units 32 resides almost enlying below the water tubes 30. Such bridge portions are acted on by the hot gases at almost maximum furnace temperature and any variation in the effective heating surface of such bridge portions necessarily changes the final temperature of the steam delivered from the superheater very materially; In accordance with the present invention, the effective surface of units 32 is varied when desired by swinging the units 32 in their sockets in the manner illustrated. by the right-hand unit in Fig. 9. After the units 32 have been swung in their sockets to the desired amount, they are held;in adjusted position by the clamping means 38, such means preferably having two spherical engaging surfaces at the points 40 so that the clamping effect of the means 38 is not decreased by changing the angles of the units 32. When the units 32 are swung, as can be done, so that all the bridge pieces of the units 32 lie substantially in contact, the effective heating surface of the superheater will be at a minimum. (See Fig. 5.) When, however, the bridge portions of the units 32 are separated to the maximum degree permitted by the joints used and as illustrated in Fig. '7, the effective heating surface and the final temperature of the steam are both at a maximum. The arrangement of the units 32 illustrated in Fig. 8 produces an amount of heating surface intermediate between those of Figs. 5 and 7.

It will be seen that I have provided means whereby considerable variation in the final steam temperature from a given superheater boiler at a given load may be produced with a high degree of certainty and small amount of labor and expense. Furthermore, in accordance with my invention, I add little, if anything, to the first cost of the apparatus.

The broad novelty herein described and claimed of adjusting the distances between elements of superheater units to Vary the effective surface of the superheater is inherent in the structure disclosed in my prior application, Ser. No. 607,334, filed April 25, 1932, but is not claimed therein.

Having thus described my invention, I claim:

1. The method of reducing the final temperature of steam from a superheater having a plurality of units including heat absorbing elements extending adjacent each other in determined spaced relation which comprises spacing at least portions of certain adjacent elements so close together as to materially lessen the effect of the gases thereon under given conditions as compared with the effect of the gases thereon under like conditions when in said determined-spaced relation.

2. The method of regulating the final temperature of steam delivered by a group of superheater units of the multi-element type, which comprises moving corresponding elements of said units to positions sufiiciently close together as to appreciably alter the effect of the gases thereon as compared with the effect when said elements are materially spaced, the effect of the gases on the superheater units being altered for substantially the same gas flow conditions.

3. The method of reducing the final temperature of steam from a superheater having a plurality of units including heat absorbing elements extending adjacent each other in determined spaced relation which comprises moving at least portions of certain adjacent elements to positions so close together as to materially lessen the effect of the gases thereon under given conditions as compared withthe effect of the gases thereon under like conditions when in said determined spaced relation, said like conditions including substantially the same gas flow over the superheater for the different relationships of said portions.

WILBUR H. ARMACOST.

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