US1920798A - Baffle for straight tube boilers - Google Patents

Description

g- 3- J. F. KAVANAGH 1,920,798

BAFFLE FOR STRAIGHT TUBE BOILERS Filed Feb. 2, 1932 ATTORNEY Patented Aug. 1, 1933 ENT OFFICE} RAFFLE FOR STRAIGHT TUBE BOILERS 1 James F.-Kavanagh, Calumet City, 111., assignor to N. Y

The Superheater Company, New York,

Application February 2, 1932. Serial No. 590,361

. 2 Claims. (01; 122-478) 7 My invention relates to baflles for boilers of thestraight horizontal water tube type and more particularly for boilers or" such type having superheaters associated therewith;

the

A well'known'type of boilercomprises generating tubes slightly inclined to the horizontal and extending in,planes substantially at right angles to the axis of the steam. and water drum together with means for completing the thermal circulation; from said drum. through said tubes and back to thedrum. It is well known also to provide bafiiing for such boilers whereby the gases :make a plurality of passes through the generating tubes. The bafiling for such boilers has been a considerable item both as to first cost and maintenance. This is particularly the case where the bafiling extends outside the bank of generating tubes, which is necessary in boilers having three gas passes.

It is the principal object of my invention to provide a baliling arrangement for horizontal straight tube boilers which shall be relatively cheap. to make and install as well as to main tain. The superheater for such boilers has often been located above the bank of generating tubes at the point of connection between an up-pass and a down-pass. In such arrangements the ends of the elements of the superheater usually extend through the bafiling so as'to place the headers inthe cooler gases of a second up-pass. This further increases the upkeep of the portion of the bathing which extends above the bank of generating tubes due to the expansion and contraction of the superheater elements.

It is another object of my inventionto provide a bafiling arrangement having reinforcement therein of an economical character and having a low upkeep, while adapted to withstand stresses due to any pipe elements which may pass therethrough.

The novel features of'my invention are pointed out in the appended claims. In order, however, that the invention itself may be fully and clearly understood, I will now describe in detail, by way of example and in connection with the accom panying drawing, a boiler in accordance with my invention selected from a number of possible embodiments thereof. In the drawing,

Fig. 1 is a sectional elevation of the upper part of a boiler in accordance with my invention.

Fig. 2 is a fragmentary sectional view. taken on the line 2-2 of Fig. 1- in the direction; of

the arrows. 1

Referring to the drawing more in detail, 10 is a steam and water drumof a boiler having a bank of generating tubes 12-12, the lower portion of which is omitted. For providing a thermal circulation from drum 10 through tubes 12 and back'to the drum, 1 have illustrated an arrangement including downcomer means comprising nipples 14 and headers 16, said nipples connecting the lower portion of drum 10 to the upper ends of headers 16. .The lower ends of tubes 12 connect into the headers 16 and the upper ends of tubes 12 connect into uptake headers 18. The upper ends of headers 18 are connected to drum 10 by circulator nipples 20, 20 in the usual manner.

For directing the heating gases through the tube bank having generating tubes 12, I have illustrated baflling means including baflle portions 22 and 24 of refractory material. Baflle portion 22 separates an up-pass 26 from a downpass 28, passes 26 and 28 connecting through a chamber 30 above the bank of tubes 12 and above upper end of bafiie 22. Baiile24 separates the down pass 28 from an up-pass 32, passes 28 and 32 being connected at their lower ends at a point not shown. Pass 32, however, extends above the bank 12 to the level of the nipples' 20 so that the gases pass out to the up-take alongside the drum 10. The bafile of which member 24 is a part extends up to the level of nipples 20.

In accordance with my invention, the baffle of which member 24 is a part is extended upwardly from the upper end of member 24 by bafliing means including water tubes 34, 34. Tubes 34 are arranged so that they have a thermal circulation therethru and in order to provide for such circulation I have shown them as connected at one end into the headers 16 just above the upper row of tubes 12. Tubes 34 extend from the headers 16 substantially parallel to the tubes 12 for only a lesser portion of the length of tubes12, tubes g 34 bending sharply upward adjacent the baflle member 24 so as to form an upward extension of the baffle of which member 24 is a part. At their upper ends, tubes 34 connect into the drum 10 so as to complete the path for the circulation of tubes water through such tubes and, in the arrangement shown, tubes 34 may be united to the circulator nipples'20 so as to deliver into drum 10 through such nipples. This arrangement reduces the number of joints necessary in the drum 10, but I do not limit myself to this. As shown, nipples 20 are interrupted intermediate their lengths to receive header members 36, 36 into which the tubes 20 and 34 are rolled so that members 36 act as Ts or Ys to unite tubes 34 with tubes 20.

Thechamber 30 forms azconvenient place for a superheater. and, I have illustrated asuperheater 38 in such a chamber. It is preferred, however, that the headers 40, 40 for superheater 38 be in the pass 32 on the opposite side of tubes 34 from the chamber 30. ,The heating surface of superheater 38 is substantially all in the chamber 30 so as to take advantage of the higher temperature of the gases in such chamber while the headers lie in the gases having a minimum tem- I perature. ,The tubes 34, however, are set sufficiently far apart so that the elements of'the superheater 38 may be readily extended between such tubes so as to connect with the headers, as shown in Figs. 1 and 2. 1

The tubes 34 serve as a support for refractory or other suitable material 42 which fills the intervals between such tubes and cooperates with 34 in extending baffle 24 up to the level of tubes 20. Such filling material therefore is maintained at substantially the steam temperature of the boiler and is largely protected'against the moresevere variations in temperature which ocour in the heating gases from the furnace. The battling above the bank of generating tubes 12 is thereby protected from deteriorating at as high rate as otherwise would be thecase. As the baflle 'portion 22 and the lower part of baflie portion 24 are necessarily protected in large measure by the tubes 12, the provision of the tubes 34 eliminates a large proportion of the deterioration in the baffling in boilers of the horizontal water tube type. Also, the extension of baffle portion 24 by tubes 34 is a relatively economical way of running such bafiling upward through the gas space above the bank of generating tubes.

What I'claim is:

1. A boiler of the type having a bank of horizontally inclined straight generating tubes, a steam and water drum, means for connecting the ends of said tubes to said drum to complete the circulation therethru, bafliing arranged to provide up and down passes for gases thru said bank, said baffling including tubes extending at a sharp angle'upward away from said generating tubes, means for causing a thermal circulation thruv thetubes in said baflling, and'a superheater having headers lying on one side of the tubes in the bafliing and its heating surface on the other side thereof.

2. A'superheater boiler of the type having horizontally inclined straight generating tubes, a

steam and water drum, downcomers arranged to connect said drum to the lower ends of said tubes, risers and substantially horizontal circulators arranged to connect the upper ends of said tubes to said drum, additional tubes above and substantially parallel to said generating tubes at the lower ends of the latter for aportion of their length, said additional tubes branching off sharply from said generating tubes and having a connection with said circulators and having also a connection with said -downcomers, baflling material on said additional tubesfor forming'a baflie therewith. I v JAMES-F. KAVANAGH.

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