US2070267A - Furnace wall construction - Google Patents

Description

Feb. 9, 1937. sc

FURNACE WALL CONSTRUCTION Filed April 24, 1931 2 SheetsSheet l INVENTOR li: lllllll Feb. 9, 1937. R sc FURNACE WALL CONSTRUCTION Filed April 24, 1931 2 Sheets-Sheet 2 INVENTOR Haw/$44 65ml Z ATNORfiEf Patented. Feb. 9, 1937 FURNACE WALL CONSTRUCTION Martin Frisch, New York, N. Y., assignor to Foster Wheeler Corporation, New York, N. YL,

a corporation of New York Application April 24, 1931, Serial No. 532,423

16 Claims.

My invention relates to furnaces, particularly to water walls thereof, and especially to an improved refractory or armor construction for water Walls.

The general purpose of providing an armor for water walls is to prevent the fire from coming into direct contact with the tubes and also to form a continuous flat or substantially continuous flat non-slagging wall made up of a plurality of blocks having high heat conductivity. These blocks being placed in contact with the tubes assure that substantially all of the heat absorbed by the wall is transferred to the water tubes and is thus usefully employed in heating or vaporizing the fluid within the tubes.

It has been proposed to provide armor block units, each made up of two members having cylindrical tube receiving recesses and curved surfaces eccentric to these recesses. The blocks making up a unit are placed with the tube receiving recesses on adjacent water tubes and with the eccentric surfaces of the tube blocks in contact with each other. Tension means is employed to rotate or swing the blocks around the tubes and to thus wedge the blocks between and against the tubes due to the eccentric surfaces. While the close contact between the blocks and the tubes resulting from this wedging action assures a good heat transfer therebetween, I have found that proper adjustment of the blocks with respect to the tube aggregate is difficult due to the tend- 1 ency of the wedging action to separate or spread the tubes. In the present .invention I provide means for aligning the tubes and preventing shifting of the tubes due to the wedging action while retaining all of the advantages derived from the use of this type of an armor block unit.

These and further objects and advantages will be apparent from the following description considered in connection with the accompanying drawings, which are to be taken as a part of this specification and on which:

Fig. l is a cross-sectional view of a portion of a boiler furnace provided with a water wall;

Fig. 2 is a cross-sectional view showing details of a water wall construction in accordance with the invention and taken partly on the line 22 of Fig. 3;

Fig. 3 is an elevational view of several block units making up the water wall;

Fig. 4 is a cross-sectional view taken on, the line 4-4 of Fig. 3; and

Fig. 5 is a perspective view of a block unit shown in position on a pair of adjacent tubes.

Referring to the drawings, Fig. 1 shows a well known type of water tube boiler having a furnace chamber I enclosed by vertical walls, including a rear water wall II and a side water wall 9. A series of vertically extending water tubes l2 pass through walls 9 and II. The lower ends of tubes l2 of wall H communicate with a header l3 while the upper ends communicate with a header l4, both of these headers being located outside of the furnace. Similar headers are provided for the tubes in wall 9. It is the usual practice to pass water through tubes l2 either before it is introduced into the boiler proper or by thermo-syphoncirculation conduits connected to the boiler proper. Any type of boiler may be used, that illustrated having water tubes I and a steam and water drum Hi. My improved water wall construction may, however, be used elsewhere than in boiler furnaces.

The lower part of furnace I0 is provided with some kind of fuel burning means, here shown as a mechanical stoker II. There is thus present in the lower part of furnace l 0 a fire which radiates heat to the surrounding walls, including walls 9 and l Water tubes I2 are provided in this wall to absorb this radiant heat. In order that the water tubes shall'not be subjected directly to the intense heat of the fire they are provided with block units l8 made of east-iron or other suitable refractory material. I]

The details of the block units in accordance with my invention are shown in Figs. 2 through 5. Each block unit l8 comprises a pair of block members l9 and 20. Members l9 and 20 are identical in form. Each member comprises a front fire face 2| of substantially rectangular shape and an adjacent convex bearing or contacting surface 22. The bearing surface of block I9 is in contact with the bearing surface of block 20 when the blocks are in position on the tubes. Each block is also provided with a cylindrical tube receiving recess 23 of substantially the same diameter as the water tubes I2. Each recess 23 is ofsufficient extent to extend around more than one quarter of -the perimeter of a tube and hence when block members of adjacent block units are in place on a tube more than one half of the surface of the tube is in contact with the blocks. The bearing surfaces 22 are curved and may be cylindrical and are eccentric with respect to thetube receiving recesses 23. In the form shown, the surfaces 22 are drawn. about centers forward of the tube centers and at the forward edges of contact of the blocks with the tubes.

The side of each block l9 opposite from the tube receiving recess is cut away at the rear portion thereof as is indicated at 24. A pair of lips or abutments 25 extend from the block proper on either side of and adjacent to the central part of each block. The central part of each block between abutments 25 is formed with a semi-cylindrical recess 26 to receive the head of an eye-bolt 21, the shank of which extends between the abutments 25. A portion of the block adjacent to the tube receiving recess is cut away between the abutments 25, as is shown at 28 in order to make room for a rigid backing member, as will be explained.

Rigid backing member 29 comprises a rectangular metallic piece provided with a flange 30 extending around the four sides thereof. The flanges at the end of member 29 are provided with apertures through which bolts 3| may be placed when the members 29 are in assembled position. The face of each member 29 opposite the side on which the flanges 30 are formed is provided with a cylindrical tube receiving recess 32. This recess is formed in part by projecting lips 33 which, when assembled, extend into the recesses 28 in the block members. The diameter of the cylindrical recess 32 is substantially the same as that of the water tubes. The length of members 29 is such that they will extend between two adjacent water tubes when these tubes are in their normal position.

In assembling my preferred form of water wall the block units comprising block members I 9 and 29 are placed in position on pairs of adjacent tubes by placing their respective tube receiving surfaces on the tubes and rotating each block around the tubes until their bearing surfaces 22 come in contact with each other. Eye-bolt 21 is then placed in position between abutments 25 on the pair of block members and a pin 34 is passed through the substantially cylindrical recess formed between corresponding abutments on the two blocks, through the eye of the eye-bolt and through the cylindrical recesses formed between the other two corresponding abutments. Pin 34 may be provided with a head 35 in order that it may be readily retained in position. The rigid member 29 is now placed in position spanning the two adjacent tubes contacted by the block unit. The shank of eye-bolt 21 passes through an opening 38 formed in the base of member 39 and a nut 31 is screwed thereon. When the eyebolt 21 is placed under tension by means of turning up on nut 31 it tends to rotate block members I9 and 20 around the respective tubes which contact their tube receivingrecesses 23. Inasmuch as the bearing surfaces 22 on the blocks are eccentric with respect to the'surfaces of the tubereceiving recesses 23, there will be a cam action between the two blocks which wedges them together and in close contact with the tubes. This force of tension also draws backing member I 29 against the tubes and the result of the wedging action of blocks I9 and 20 and the action of member 29 is that there is a tendency to spread the tubes apart. This tendency is overcome by securing. adjacent backing members 29 together by means of bolts 3 I.

On each corner of the furnace there are provided steel upright members 38 protected by refractory blocks 39. Two vertical faces of blocks 39 contact the upright members 38 while two other vertical faces contact the extended ends of corner block members 4i and are thus retained securely in place; One. end of the rigid members 29 adjacent to member 38 is secured thereto by means of a bolt 40. As all the rigid members 29 are secured to each other by means of bolts 3| there results a rigid backing structure supported at each end by means of members 38. This structure serves to retain the water tubes I2 in their normal position and prevents spreading of the tubes due to the wedging action of the block units I8.

If desired some or all-of the eye-bolts engaging the block units I8 may be of suflicient length, as shown at 43 (Fig. 2), to extend not only through rigid members 29 but through apertures formed in a horizontal channel 44 comprising the furnace wall. In this event, a sleeve 45 is provided around bolt 43, the ends of sleeve 45 bearing against rigid member 29 and channel 44. Sleeve 45 hence is a compression member between channel 44 and rigid member 29 and forces the latter against tubes I2. By this arrangement the rigid structure made up of rigid members 29 is securely fastened to the remainder of the furnace wall.

As will be seen in Fig. 2, the corner blocks 4| are constructed somewhat differently from the blocks I9 and 29. The end of block 4| which contacts block 20 is similar to block 28 but the other end of block 4| is extended to contact members 39 as previously explained. With this arrangement the block member 4I engages the end tube for approximately one-half its circumference so that the end tube is securely clamped between the block member M and the rigid member to which it is secured. The wedging action of blocks M and 28 is exactly the same as that of blocks I9 and 29.

A number of block units are placed one above the other on all pairs of adjacent tubes, thus forming a substantially solid wall. The rigid members 29 extend in horizontal rows behind the tubes. It is not necessary that members 29 in all the rows be secured together by bolts 3 I, although this may be done if desired, as I have found that the tubes are prevented from spreading if the members 29 constituting, for insance, every fifth row are secured together.

After the blocks have been assembled with the backing memberson the water tubes the spaces remaining therebetween may be filled with a plastic refractory material shown at 42.

.While I have shown one specific embodiment of my invention, it is to be understood that modifications thereof which would occur to one skilled in the art fall within its scope which is to be limited only by the appended claims viewed in the light of the prior art.

What I claim is:

1. A furnace comprising two vertical walls meeting to form a right angle, a pair of upright members adjacent to the apex of said angle, a plurality of vertically extending spaced parallel tubes comprising said walls, rigid structures having curved tube recesses, means securing said rigid structures to each of said upright members, a plurality of block units comprising two block members, said block members having curved tube recesses, tension means engaging said block members and said rigid structures, and refractory blocks located at the apex of said angle and abutting against said upright members, the block members contacting the tubes adjacent to the apex of said angle being extended to contact said refractory blocks and retain them against said upright members.

2. The combination with spaced parallel tubes, of a block unit comprising two complementary block members between said tubes, said block members having curved tube recesses and curved contacting surfaces eccentric with respect to said tube recesses, each block member contacting a tube for more than one-quarter of the circumference of the tube, rigid backing means straddling the space between said tubes and having tube contact recesses and adapted to prevent spreading of the tubes, and stress means engag-i ing said rigid backing means and said block members for pulling the block members toward the backing means to exert pressure between the eccentric surfaces, said backing means having contact with said tubes for substantially one-quarter of the tube circumference, and said block membiers and backing means having overlapping port ons.

3. The combination with spaced tubes, of a block unit comprising two complementary block members between and in front of said tubes, said block members having curved tube recesses and curved contacting surfaces eccentric with respect to said tube recesses, rigid backing means straddling the space between said tubes and having tube contact recesses and adapted to prevent spreading of the tubes, and stress means engaging said rigid backing means and said block members for pulling the block members toward the backing means to exert pressure between the eccentric surfaces, said block member-shaving rear recesses, and said backing means having tube contacting projections extending into the rear recesses of the blocks.

4. The combination with spaced tubes, of a a block unit comprising two complementary block members between and in front of said tubes, said block members having curved tube recesses and curved contacting surfaces eccentric with respect to said tube recesses, rigid backing means straddling the space between said tubes and having tube contact recesses and adapted to prevent spreading of the tubes, and screw-threaded stress means engaging said backing means and said block members for pulling the block members tor ward the backing means to exert pressure betary block members between adjacent tubes, said block members having tube recesses and contacting surfaces eccentric with respect to the tube recesses, a rigid member extending transversely of the tubes and for a distance greater than the axial distance between adjacent tubes, said rigid member having recesses to receive said tubes, and stress means engaging said block members and said rigid member for pulling the block members toward the rigid member to exert pressure between the eccentric surfaces, the extent of the contact between said rigid member and one of the tubes and a block member and said tube being suificient to clamp the tube between said rigid and block members when the blocks are secured thereto.

6. An armored wall structure comprising a-row of spaced tubes, a plurality of armor block units having tube recesses in which the tubes are re ceived, a plurality of rigid members extending transversely of the tubes and between adjacent other.

of the tubes, the rigid members engaging the tubes with which they are in contact for substantially one-quarter of the tube circumference, the block units and rigid members having overlapping portions, whereby the tubes are secured against transverse displacement with respect to each they are in contact for more than one-quarter of the circumference of the tubes, the other of said two first mentioned means engaging the tubes with which they are in contact for substantially one-quarter of the tube circumference, the block units and rigid members having overlapping'portions, whereby the tubes are secured against transverse displacement with respect to each other.

8. An armored wall structure comprising a row of spaced tubes, a plurality of armor block units having tube recesses in which the tubes are received, a plurality of rigid members extending transversely of the tubes and between adjacent tubes and having recesses to receive the tubes, means for securing the block units and the rigid members to the tubes, and means for securing adjacent rigid members together, the block units engaging the tubes with which they are in contact for more than one-quarter of the circumference of the tubes, the rigid members engaging the tubes with which they are in contact for substantially one-quarter of the tube circumference, the block units having recesses in which portions of the rigid members are received, the block units and rigid members having overlapping portions, whereby the tubes are secured against transverse displacement with respect to each other.

9. An armored wall structure comprising a row of spaced tubes,- a plurality of armor block units having tube recesses in which the tubes are received, a plurality of rigid members extendin transversely of the tubes and between adjacent tubes and having recesses to receive the tubes, means for securing the block units and the rigid members to the tubes, and means for securing adjacent rigid members together, the block units engaging the tubes with which they-are in contact for more than one quarter of the circumference of the tubes, the rigid members engaging the tubes with which they are in contact for substantially one-quarter of the tube circumference, portions of the block units and rigid members overlapping between adjacent tubes, the block units and rigid members having overlapping portions, whereby the tubcs are secured against transverse displacement with respect to each other.

10. An armored wall structure comprising a, row of spaced tubes, a plurality of armor block units, each comprising two complementary block members having tube receiving recesses and contacting surfaces eccentric with respect to the tube recesses, a plurality of rigid members extending transversely of the tubes and between adjacent tubes and having recesses to receive the tubes, means for securing the block units and the rigid members to the tubes, one of said block members and the rigid member to which it is secured being arranged to clamp one of said tubes therebetween, and means for connecting the last mentioned rigid member to the adjacent rigid member.

11. An armored wall structure comprising a row of spaced tubes, a plurality of armor block units, each comprising two complementary block members having tube receiving recesses and contacting surfaces eccentric with respect to the tubes recesses, a plurality of rigid members extending transversely of the tubes and between adjacent tubes and having recesses to receive the tubes, means for securing the block units and the rigid members to the tubes, .one of said block members and the rigid member to which it is secured being arranged to clamp an end tube therebetween, and means for connecting the rigid member engaging said end tube to the adjacent rigid member.

12. An armored wall structure comprising a row of spaced tubes, a plurality of armor blocks each having tube receiving recesses, a plurality of rigid members extending transversely of the tubes and between adjacent tubes and having recesses to receive the tubes, means for securing the blocks and the rigid members to the tubes, one of said blocks and the rigid member to which it is secured being arranged to engage oppositely disposed portions of the circumference of one of the tubes, said portions being disposed at both sides of the axis of the tube in a direction transverse to the tube axis and substantially parallel to the rigid member to clamp said one tube therebetween, and means for connecting the last mentioned rigid member to an adjacent rigid member.

13. An armored wall structure comprising a row of spaced tubes, a plurality of armor blocks each having tube receiving recesses, a plurality of rigid members extending transversely of the tubes and between adjacent tubes and having recesses to receive the tubes, means for securing the blocks and the rigid members to the tubes, one of said blocks and the rigid member to which it is secured being arranged to engage oppositely disposed portions of the circumference of an end tube said portions being disposed at both sides of the axis of the tube in a direction transverse to the tube axis and substantially parallel to the rigid member to clamp said end tube therebetween and means for connecting the rigid member and engaging the end tube to the adjacent rigid member.

14. An armored wall structure comprising a row of spaced tubes, a plurality of armor blocks each having tube receiving recesses, a plurality of rigid members extending transversely of the tubes and between adjacent tubes and having recesses to receive the tubes, means for securing the blocks and the rigid members to the tubes, one of said blocks and the rigid member to which it is secured being arranged to engage oppositely disposed portions of the circumference of each end tube, said portions being disposed at both sides of the axis of each tube in a direction transverse to the tube axis and substantially parallel to the rigid member to clamp each of the end tubes therebetween, and means for connecting all of said rigid members together.

15. A furnace comprising walls meeting to form an angle, members adjacent the apex of the angle, a plurality of spaced parallel tubes comprising said walls, rigid structures having tube recesses, means for securing the rigid structures to said members, a plurality of armor blocks having tube recesses, means engaging the blocks and the rigid members for securing them to the tubes and refractory blocks located at the apex of the angle, the blocks in contact with the tubes adjacent the apex of the angle having a portion in contact withthe refractory blocks.

16. A furnace comprising walls including a plurality of spaced tubes, said walls meeting to form an angle, armor blocks having tube recesses, rigid structures having tube recesses, means engaging the blocks and the rigid members for securing them to the tubes, and refractory blocks located at the apex of the angle, the blocks in contact with the tubes adjacent the apex of the angle having a portion in 'contact with the refractory blocks.

MARTIN FRISCH.

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