US2571006A

US2571006A - Armor block construction

Info

Publication number: US2571006A
Application number: US73172A
Authority: US
Inventors: Biery John Edward
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-01-27
Filing date: 1949-01-27
Publication date: 1951-10-09
Anticipated expiration: 1968-10-09

Description

1951 J. E. BIERY 2,571,006

' ARMOR BLOCK CONSTRUCTION Filed Jan. 27, 1949 2 Sheds-Sheet 1 W twig ,5

Oct. 9, 1951 J. E. BIERY ARMOR BLOCK CONSTRUCTION 2 Sheets-Sheet 2 Filed Jan. 27, 1949 INVENTOR. Jo BY M,W,%$ W

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Patented Oct. 9, 1951 P v UNITED STATES PATENT OFFICE 2,571,006 ARMOR BLOCK CONSTRUCTION John Edward Biery, Jersey City, N. J. Application January 27, 1949, Serial No. 13,172 4 Claims. (01. 122-6) 1 v This invention relates to armor or. refractory coverings for heat absorbing members, and more particularly to armor blocks for the water tubes of water tube boilers or other types of heat exchangers having tubes carrying fiuids to be heated. In one aspect, improved mechanism for securing armor blocks to water tubes or the like for the purpose of maintaining an even protective covering across the face of the tubes and for maintaining a uniform pressure between the blocks and the tubes, under conditions of misalignment. In another aspect, thisinvention relates to improvements in armor blocks for prolonging their useful life and for reducing their initial cost of construction.

Armor blocks are generally made. out of cast iron and are fitted to thefire tubes of water tube boilers adjacent to the hottest portions of the fire box. In general, the construction of armor blocks is concerned with protecting the tubes on the one hand, and on the other hand, with providing armor blocks which will. not cake up with slag, which will be inexpensive andwhich will last.

Among important considerations is the provision of. armor blocks which will provide relatively cool surface adjacent to the fire and for this reason they are called chill blocks in the industry. If the transfer 3. of heat is not rapid deposits of slag accumulate on the surface of the fire wall to the further detriment of proper heat exchange. It is also important for the purpose of the smooth passage of coal and ash to provide blocks which will not shift in position, but which will maintain an even protective front across the face of each tube. Another consideration is the reduction of air space between the armor blocks and the tubes. Air space impedes the transfer of heat from the blocks to the tubes, thereby reducing the efiiciency of the boiler and causing the blocks to burn off prematurely. Another consideration is the effect of block and tube expansion or contraction under conditions of temperature change. When extremely hot and expanded, the blocks should not be loose on the tubes nor should they exert excessive pressure on the tubes when cooled and contracted. Still another consideration in armor block construction involves the effect of misalignment of tubes upon the alignment of the blocks. If the tubes are out of alignment, intentionally or otherwise, the blocks may tend to tilt or otherwise spread and expose the tube surfaces to the extreme temperatures of the fire this invention relates to a side of the water box, or else exert uneven pressure against the tubes. A further consideration is the path of heat transfer within the blocks themselves. If the transfer of heat from a given portion of the block is poor, that portion may burn off prematurely or else set up internal stresses within the block due to uneven expansion, which stresses may eventually cause the block to crack.

These construction considerations introduce certain anomalous situations. For instance, if

greater pressure is used to reduce the air space between the blocks and the tubes and make the tubes conform to the blocks, such pressure is harmful to the tubes and causes them to crack. On the other hand, if the blocks are securedless firmly, they will tend to tilt and expose the surfaces of the tubes. In the past, when the tubes have been out of alignment the armor blocks have either been held rigidly to each other, causing gaps to appear across the face of the individual tubes, or, if the blocks have been allowed to separate and adhere to the bent tubes,

they have tilted and exerted uneven pressure against the tubes. Another disadvantage seen in previously used armor blocks is a shifting in the direction of thrust of the armor block upon the tube during conditions of expansion or contraction; such shifting causes the blocks to tilt and eventually to expose or bend the tubes.

surface, against the tubes.

Another object of my invention is to provide an inexpensive armor block construction with improved qualities of wear, and in which expansion and contraction due to changes in temperature are kept to a minimum.

' Still another object of my invention is to provide mechanism for securing the armor blocksto the tubes which mechanism will cause the blocks to exert a substantially unidirectional force against the tubes whether in condition of expansion. or contraction.

In the accomplishment of these objects, I employ armor block units including two blocks fitting between two adjacent tubes and each shaped to conform to approximately one quarter of the tube surface. These blocks placed side by side are held in place by a cylindrical retaining bolt which fits between the blocks in opposed recesses in the blocks. The retaining bolt both draws the blocks together between the tubes and serves to press the blocks against the tubes. The bolt is then connected to a bridge structure which fits across the back of the two adjacent tubes.

It is a feature of my invention that the retaining bolt has a cylindrical body portion and a head in the shape of an expanding cone, and that the recesses in the armor blocks into which the retaining bolt fits, are semi-cylindrical and semiconical. Thus when the blocks are placed together, the composite matrix formed is substantially inverse in shape to the retaining bolt. However, it is a further feature of my invention that the conical portions of the recesses are not exactly inverse but taper at a slightly less angle of divergence than that of the bolt head. Thus the point of most intimate contact between the bolt and the blocks is nearest the fire wall and the direction of thrust of the block against the tube is more near the center of gravity of the block. In combination with this latter feature of my invention is a spacer sleeve which holds the blocks at a given distance from the back bridges in order to prevent the blocks from wedging too tightly between the tubes when the retaining bolt is tightened. These spacers also provide a pivot point for the blocks which will be described in detail below.

Still another feature of m invention is the use of a short retaining bolt for purposes of minimizing expansion effect and for reducing the dead space between the backs of the tubes and the boiler insulational wall, or other tubes.

Further objects and features of my invention will best be understood and appreciated from the followin detailed description of a preferred embodiment thereof selected for purposes of illustration and shown in the accompanying drawings in which:

Figure 1 is a view in front elevation of the fire sides of a water tube boiler equipped with the armor blocks of my invention;

Figure 2 is a view in side elevation of the corner of the fire box, showing one of the corner blocks ofmy invention in its installed position;

Figure 3 is a view in side elevation of one of the corner blocks of my invention;

Figure 4- is a rear view ofthe block shown in Fig. 3;

Figure 5' is a view in side elevation of the armor block of my invention adapted for use on a curved tube;

Figure 6 is a view in cross section of the block shown in Fig. 5;

Figure 7 is a plan view from above showing the blocks of my invention in installed position;

Figure 8 is a view in side elevation along the lines 88';

Figure 9 is a view in front of elevation showing the blocks of my invention under conditions of tube misalignment;

Figure 10 is a view in near elevation of the bridge which provides support for the blocks;

Figure 11 is a sectional view of the bridge along the lines H H;

Figure 12 is a view in side elevation of'the bolt used in supporting the blocks;

Figure 13 is a view in side elevation of the armor block of my invention; and

Figure 14 is a sectional view of the block along the lines I4-l4.

The general organization of the preferred embodiment of my invention herein shown may be seen generally in Fig. '7, and includes armor blocks 20 'held against water tubes 21-, by bolts 22. The

cent tubes 2|.

4 bolts 22 fit into a recess 23 in the blocks. 20, and are held from the rear by bridges 2a which span the rear of the tubes.

The blocks 20 are shown more in detail in Figures 13 and 14. They may preferably be made of cast iron, and are identical in structure being alternately inverted when installed. The blocks 20 are provided with a quarter-cylindrical longitudinal recess 36 which subtends an arc the radius of which is the sameas the radius of the tubes (with slight allowance for a coating of binder 32 between the tubes and the blocks). The blocks 20 are also provided with centrally located recesses 23 on the side of the block opposite to said longitudinal recesses 30. The recesses 23 are disposed normal to the longitudinal axis of the blocks and are provided with a semicylindrical shank portion 25 and an expanding cone end section 26. The recesses 23 compositely form a matrix and serve to accommodate the retaining bolt 22 which is provided wi h cylindrical shank portion 2'! and an expanding conical shaped head 28.. It. will be noted, however, that the conical section 26, of the recesses 23 tapers at a slightly less angle of' divergence than that of the head 2Bv of the. bolt 22. Thus. the most intimateoontact of the; bolt 22 against the blocks. 29 is, at the point ofthe recess 23 nearest. the. fire side. The forward wall of the conical re:

cess itv likewise tapers toward the fire wall. but.

at a much greater angle. The reason for this taper is to reduce the amount of metal between the fire Wall and the air space formed by the, recess 26. With reference to Fig. 7 it will be seen that the block as. actually are spaced somewhat apart in the normal position and therefore the heat, from the fire penetrates a short distance between the blocks andis applied 11. h ur a of the blocks within the slotformed between the two blocks. Turning now to Fig. 14 it will be seen that if the recess, 25 .did not taper on its; forward surface a. full thickness of' metalwould exist from the base of the recess to itsv periphe c y. This. condition would be undesirable because the path of conduction of heat from the center axis of" the. forward wall of the recess outward and through the block would not be an expanding path, and for this reason the fire would tend to burn off the block in the area adjacent to the fire just outward of the recess 26. By taper ing the forward Wall of the recess 26 as shown in Fig. 14, an expanding path for the heat is provided and-the tendency of the block to burn off on the fireside of this area is thereby reduced. The rear wall of the blocks 20 may be cut away as indicated generally at 3'5, but that a shoulder 34 remains around the shank portion of the recess; 23.

The bridge 24 is shown in detail in Figures 10 and 11-, and includes cylindrical end walls 31, a bottom. wall 38-, and side walls 40. The bottom wall 38. is provided with a hole M to receive the bolt 22, which hole has a flat side 42 corresponding to a similar flat side 43 of the shank portion 21" of the bolt 22 and is useful to prevent the bolt 22 from rotating when being tightened. The bridge 24 is wide across its midsection and narrow at each end. This provides a narrow point of contact on the rear face of; the tubes rendering the bridge better adapted for changes in tube alignment.

In the assembly of the armor blocks, the bolt 22 fits into the recesses 24' of two blocks 20; and draws the blockstogether and; towards two adja A sleeve spacer 46 is then placed it is to be notedzgsvnooa on the bolt 22, and after it, the bridge 2|, a spring washer 41 and a nut 48. The spacer 46 abutsagainst the shoulders 34 and prevents the bolt 22 from tilting the. blocks inward or otherwise drawing the blocks 20 too far between the tubes 21. Thus, it will be seen that the spacer 46 provides a fulcrum, and the blocks 20, rather than wedging themselves between the tubes, will pivot at their points of contact with the spacers 46. Furthermore, due to the differences between the taper angle of the recess 23 and that of the bolt head 28, the thrust of the bolt 22 against the block will be substantially through the center of gravity of the said blocks. Although minor variations will occur due to expansion and contraction the direction of thrust will remain substantially uniform. It is to be noted however that the shape of the spacer 46 may be varied as desired to adjust the position of the said pivot point. Furthermore, since the bolt 22 bears against the blocks 20 only at its extremity nearest the fire wall, the direction of thrust of, the bolt 22 will be more nearly through the center of gravity of the blocks and towards the centers of the tubes. The spring washer 41 urges the bolt 22 against the blocks 20 and provides for a substantially constant pressure between the bolts 22 and the blocks 20. Although, the blocks 20 are not drawn between the tubes 2| in such a way as to exert extreme pressure in separating them, the pivoting pressure is significant, and the bridges 24 are preferably joined across the rear of the tubes in order to prevent separation of the tubes. To this end, the bridge 24 are welded to each other at 50.

If the tubes 2| separate after long periods of use (see Fig. 9), or if it is desired to separte them intentionally, the blocks 20 will adhere to the tubes 2|, being thrust apart by the bolts 22. In addition, if such spreading entails a misalignment of the blocks, the bolts 22 being circular will not cause the blocks to tilt but will continue to hold the blocks 26 uniformly against the tubes.

The armor blocks of my invention may be readily adapted for use in the bottom corners of the fire box as shown in Figures 2, 3 and 4, wherein a block. 55 is provided with a massive center portion and 9, depending protective flange 58. Also the blocks may be adapted for use with curved tubes as shown in Figures 1, 5 and 6, by casting a block 56 in curved form. Of course, it will be understood that the blocks used in such adaptations are not identical but require individual right and left hand castings. However, they include the significant features of the straight block described above with respect to angle of divergence of the recess 23, the shoulders 34, and cut away portions 35. Furthermore, they are held in place by bolts 22 which communicate with bridges 24, they abut against spacers 46, they are urged by spring washers 41, and they are secured by nuts 48.

Since other variations will suggest themselves to those skilled in the art without departing from the concept of this invention, it is not intended to limit the invention to the details of the preferred embodiments herein shown, but rather to measure it in terms of the appended claims.

Having described in detail a preferred embodiment of my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. An armor protection unit for spaced tubes comprising two opposed blocks recessed laterally to receive the tubes and to fit partly betwee the tubes and partly covering the face of the tubes, the said blocks each being recessed centrally in their opposed sides to form one-half of a composite matrix, anchoring means to the rear of said tubes, a bolt with an enlarged head communicating at one end with the said blocks Within said matrix, and at its other end with said anchoring means, the said enlarged head bearing upon the blocks only at its extreme periphery, the bolt being further adapted both to draw the blocks between the tubes and to wedge the blocks apart against the tubes, and means including a rigid member extending forward from said anchoring means adapted to abut said blocks and thereby prevent the bolt from drawing the blocks between the tubes beyond a predetermined point whereby the blocks will thereafter pivot toward the tubes in response to the wedging action of the bolt within the said recesses.

2. Armor covering for spaced tubes including opposed blocks in contact only with forward surfaces of the said tubes, a bolt having a cylindrical shank and a head in the shape of an expanding cone, the said blocks each being recessed in their opposed sides to form one-half of a composite matrix inverse in shape to the shape of the bolt, a bridge spanning the rear of the tubes and spacer means including a rigid member extending forward from said bridge abutting the inner face of said blocks adjacent said bolt; the said bolt secured at one end to the bridge, its conical end fitting into the said matrix, drawing the said blocks toward the bridge and pivoting the said blocks apart against the said tubes with said spacer means serving as a fulcrum.

3. Armor covering for spaced tubes including opposed blocks in contact with forward surfaces of the said tubes, a bolt having a cylindrical shank and a head in the shape of an expanding cone, the said blocks each being recessed in their opposed sides to form one-half of a composite matrix inverse in shape to the shape of the bolt but expanding at a slightly less angle of divergence than that of the head of the bolt, a bridge spanning the rear of the tubes; the said bolt secured at one end to the bridge, its conical end fitting into the said matrix, drawing the said blocks toward the bridge and wedging the said blocks apart against the said tubes; and a spacer between the blocks and the bridge preventing the blocks from being drawn toward the bridge beyond a predetermined point and providing a fulcrum whereby the blocks will pivot from their points of contact with the spacer towards the tubes in response to the wedging action of the said bolt.

4. Armor covering for spaced tubes including opposed blocks in contact with the forward surface of the said tubes, a bolt having a cylindrical shank and having a head in the shape of an expanding cone, the said blocks each being recessed in their opposed sides to form a half conical and half cylindrical recess so located that when two of the blocks are placed in opposed relationship in contact with the tubes a composite matrix is formed opening rearwardly, the cylindrical portion of the composite matrix coinciding with the shank of the bolt, but the conical portion having a smaller angle of divergence than that of the conical head of the bolt, and a bridge spanning the rear of the tubes; the said bolt having its shank end secured to the bridge, its conical head fitting in the said matrix, drawing the said blocks towards the bridge and wedging mammee 7 8 file: said blacks apart against the tubes; and; means preventing the bolt from drawing the: UNITED STATES-PATENTS blocks between the tubes beyond a predetermined N b' N Dat point, providing aiulcrum about which the. blocks 304,957 Shellenzberger May 12', 1931. will rock against the tubes. 5 1,311,373 Thayer June- 23, 1931 H EDWARD R 2,023,302 Bennett Dec. 3, 1935 2,028,142- Blizard Jan. 21, 1936 REFERENCES CITED 033,175: Biery Mar. 1.0, 1 936 The following references are of record in the file of this patent: