US1563567A - Baffle and method of constructing the same - Google Patents

Description

Dec. 1,1925. 7 1,563,567

V I. HARTEW BAFFLE AND METHOD OF CONSTRUCTING THE SAME Filed March 7; 1921 5 Sheets-Sheet 1 INVENTOR ATTORNEYS @em 1, 1925. I 1,563,567 V I. HARTER BAFFLE AND METHOD OF GONSTRUCTING THE SAME Filed March '2', '1921 v -5 Sheets-Sheet 2 INVENTOR Mme ATTORNEYS Dec. 1., 1915;. 1,583,563?

. I. H'ARTER f BAFF'LE METHOD OF CONSTBUQTING THE SAME Filed March 7, 1921 5 sheefs Sheet s ATTORNEY Dec. 1; 1925- 1,563,567

I. HARTER BAFFLE AND METHOD OF CONSTRUCTING THE SAME Filed March 7, 1921 s Sheets-Shet 4 ll INVENTOR ATTORNEYS Dec. 1,1925

I. HARTER BAFFLE AND METHOD OF CQNSTRUCTING THE SAME Filed March '7, 1921 heat 5 V .5 Sheets-S INVENTOR we. m

%4+ ATTORNEYS Patented Dec. 1, 1925.

UNITED STA'E'Ed tsetse? FFICE. v

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ISAAC} I-IARTER, F DONGAN HILLS, NE'WYGRK, ASSIGNOR TOTHE BABCOCK 8c WIL- COX COMPANY, OF BAYONNE, NEVJ S'ERSEY, A COBPGBATION OF NEW JERSEY.

BAFFLE AND METHGD OF CONSTRUCTIHG THE SAIVIE.

Application filed March '7, 1921.

To all, tUhO'ilt may concern.

Be it known that 1, Isaac Han'rnn, a citizen of the United States, residing at Dongan Hills, in the county of Richmond and State 6 of New York, have invented certain new and useful Improvements in Battles and Methods of Constructing the Same, of which the following is a specification.

My present invention relates to improvements in ballles for water tube boilers or the like, and the methods by which such battles may be constructed, and particularly where the baffle is of the type which is'installed in the boiler after the same has been erected.

One of the objects of my invention is to provide a battle which may be entirely of metaland yet be. cable of withstanding the heat from the gases passing thebaftle. Another object of my invention is to form a metallic battle which will be made up of separable plates, each of which will be held in place in the battle by engaging with the boiler tubes, thus obviating the use of backing bars or the like to hold the baffle against warping. Another object, of my invention is to form a baille of a plurality of plates fastened together by means which can be readily removed so that any desired number of plates may be taken out of the baflle when a tube cannot be removed otherwise, or when, for any reason, any of the plates have become damaged. Another object of my invention is to provide a method by which a baffle, comprising a plurality of separable plates, may be readily erected and removed from the tubes of a boiler after the boiler itself has been erected.

lVith these and other objects in view, my invention consists in the constructions, arrangements and methods hereinafter described and more specificallypointed out in the appended claims.

In the d'awings, Figure 1 is a sectional elevation of a well-known type of a steam boiler having horizontally inclined water tubes in which a preferred form of my ia'llle is shown in position; Fig. 2 is a front elevation of a part of one form of batlie constructed according to my invention; Fi 3 is a side view, partly in section, of Fig. 2; Fig. -1 is a section of Fig. 3 on the line 4t 4i; Fig. 5 is an elevation of Fig. 4; Fig. 6 is a partial view similar to Fig. 3 showing a modified form of fasteningdevice; Fig. 7

is a section through the side, plates which Serial No. 450,167.

connect the battle to the boiler wall, showing the connection between such plates and the battle plates; Figs. 8 and 9 are, respectively, front and side elevations of another form of myinvention; Fig. 10 is a side elevation showing still another modification of the plate arrangement; Figs. 11 and 12 are enlarged views of two specific forms of fastening devices which may be used in carrying out my invention; Figs. 13 and 14: are. respectively, front and sectional elevations of a part of a baflle showing a modification cons'ructed according to my invention, Fig. 14 being a section on the line 141 l of Fi 13, but with a less number of plates therein than in the arrangements shown in the preceding figures; Figs. 15 and 16 are, respectively, front and sideelevations of a portion of a bafile showing a modification with relatively large plates, Fig. 16 being a section on the line 1515 of Fig. 15; Figs. 17 and 18 are, respectively, side elevation and plan view of a form of tool which may be used to insert the fastening devices in one embodiment ofmy invention, and Fig. 19 is still another tool which may be used for inserting the bolts.

Like reference characters refer to like parts in the several views.

It is well known that the usual metals, such as cast or wrought iron or steel, when subjected to hot furnace gases, will soon be destroyed. Various methods have been proposed to prevent. parts made of such metal from being attacked by the hot gases, and some of them have been fairly successful.

When such methods are applied to iron parts in water tube boilers, however, even if the protection is efiective, still there is the considerable waste of heat and the expense in applying such protection to offset their advantages.

I have found by experiment that a baffle made of cast iron or steel plates may be maintained under severe conditions in a water tube boiler, if the battle is arranged in such a way that there is a considerable area of contact between the parts of the bafile and the exterior of the water tubes, so as to permit the heat which is absorbed by the metallic bafile from the gases to pass readily into the water tubes and from thence to the water being heated. This can only be done, however, by having the contact between the tubes and the bailie, not only relatively large in area, but also very close. lVhen a balile is thus constructed, it is found that the heat is carried away from the baffle parts into the water tubes with sufficient rapidity to keep the temperature of the baiiie down to a point where substantially no destruction results. It will also be obvious that such heat is ap plied usefully to the water to be heated.

In the drawings, I have illustrated several forms in which these ends may be accomplished. In general, I form av halite of metallic pieces or plates, the edges of which are provided with curved surfaces of exactly the shape of the external curved surface of the tube with which they are to engage, and I then provide means by which the surface of the tube and the curved surface of the plate will be forced together under SUifiClOlit. pressure to give a good thermal contact, the curved surface of the plate preferably being formed so that it contacts substantially throughout its entire area.

In the several forms of my invention which I have illustrated, the baflie which, as is usual, will extend across all or a large portion of the tubes of the boiler, is made up of a number of relatively small plates, each of which is in reality substantially rhombic in outline but which, because of the circular recesses on the several edges of the plate and the rounding of the corners, appears to be of irregular outline. In the forms illustrated, these circular recesses are formed to lit the exterior of the tube very closely and, preferably, these recesses will be formed with considerable accuracy to the correct diameter to fit the tubes. The walls of these recesses are also cylindrical for substantially the entire thickness of the plate so that the area of the plate, which will be in con tact with the tube, is necessarily considerable. Furthermore, the recesses preferably are each such that the walls extend around the tube with which they are in contact for a considerable arc, iii the forms shown this are varying from approximately 60 degrees to nearly 180 degrees for each recess. liloreover, when a plate has one recess making contact for as little as 60 degrees, preferably, it or other adjacent plateshave other recesses making a much longer contact with the tube with which they engage.

In each of the forms of my invention lllustrated, the plates forming the battle are also shaped so that, when they are in position, a portion of the surface of one plate will overlap a portion of the surface of one or more of the adjacent plates and, preferably, fastening devices pass through these overlapping portions to hold the plates in correct relation to each other and to bring the surfaces of the several plates together to form gas-tight joints and to give heat con-- ductivity between two adjacent plates in the event that, through any faulty construction,

one or more plates may not be in suliicient thermal contact with the tubes to keep their temperatures below the destruction point.

Referring now to the several specific arrangements shown in the drawings, Figure 1 is a cross-section of a Babcock & lVilcox boiler of a well-known type and having a set of horizontally inclined tubes 10 engaging the usual headers 11, 12, and having a horizontal drum 13 and a superheater 14-.

A battle, which I have designated gener ally by the character 15, is inclined to the vertical and also makes an angle with the tubes themselves, so as to form the first pass which gradually decreases in area. The lower part of the batlie 15 engages a horizontal bafiie l6 resting on the lower tubes of the set 10, and the opposite end of the battle 16 engages a short vertical balile 17 resting on the wall 18. At the upper end of the baffie 15 is an inclined plate 19 to direct the gases from the first pass over the superheater.

The second gas pass is formed between the baflie 15 and a second and shorter batlle 20, the latter being made up in accordance with my present invention, and the gases being directed to the battle 20 by a plate 21 from the superheater 14-.

It will be understood that a baltle embodying my invention may make any desired angle with the tubes 10, and that the constructions which I am about to describe may be embodied in either of the battles 15 or 20.

Turning now to Figures 2 to 5, inclusive, I have shown a portion of a bafiie made up of a plurality of metallic plates 21. In this form each plate is in reality substantially a rectangular quadrilateral in outline, the corners being rounded 05 as a matter of convenience in manufacture and the end faces of the plate being provided with circular recesses, each of which fits around one of each group of four tubes, the centers of which are in the corners of a parallelogram. The area of each plate extends beyond the line of centers connecting the several tubes with which the plate 21 is in engagementand, since the several plates forming the baffle are substantially alike, (except the external or outside plates which are necessarily modified, but in a manner which will be obvious and will not require further explanation), the arrangen'ient just described will give overlapping portions between adjacent plates, and through these overlapping portions I pass fastening devices which will draw the plates together and hold them, so that, after the plates are all assembled, it would be possible to withdraw all of the tubes and the battle would be maintained in correct position.

In the arrangement shown in Figures 2 and 3, the plates are arranged as they would be to form a vertical battle and they are arranged alternately, front and rear. The recesses 1n the end surfaces of the plates are not only formed so as to have a radius substantially the same as the external radius of the tube, but the respective centers of these radii also correspond with the centers of the tubes with which the plate is to engage, so that, when the plate is in position, each tube is pressing into engagement with the surface of a recess, this pressure being relatively easy to produce by my novel method which will be described hereinafter.

In the form shown in Figures 2 and 3, the fastening devices consist of a bolt-like member 22 passing through corresponding openings in the overlapping plates and being provided with akey-like cotter-pin 23, the legs 24; and 25 of the pin being adapted to be spread apart to hold the pin 23 in position after it has been driven downward in Figure st to draw the plates together by a wedge action. The upper and lower parts of the battle may be formed by plates, such as 26, which may be fastened to any appro priate part of the boiler structure, and, similarly, the sides of the battle may be formed of plates, such as 27, which will be fastened to the side walls. The sides of the plates 26, 27 toward the boiler tubes will be formed with recesses in a manner similar to that described for the plates 21', and with overlapping portions through which fastening devices will pass from the plates 21.

In Figure 6 the form of fastening device, which is in reality a rivet 28, is shown as being used in place of the bolt 22, the inner end of the rivet 28 being upset by the insertion of a plug 29. While this form of fastener is relatively simple, it is obvious that it will be ditlicult to remove it without cutting, in the event that one or more plates are to be removed after the baffle has been set up.

In Figures 8 and 9, plates 21 are shown formed so as to enable the construction of a battle making a. relatively large angle with the tubes as would be the case with the baffle 15 shown in Figure 1. In the form shown in Figures 8 and 9, the plates 21 are provided with hubs or bosses 30 so that an ordinary bolt 31, provided with a nut 32, may be used, if desired, to fasten the plates togethcr.

In Figure 10, a form of my invention is shown in which some of the plates, for instance, the center plate in each group of five, are provided with a duplicate plate at the. rear, so that the overlapping portions of the adjacent plates extend between a pair of plates, as shown clearly in Figure 10. Hence a single bolt 33, tightened by a nut 34, will serve to hold a number of plates in position by friction or the clamping pressure between the two opposite plates.

Figure 11 shows a form of fastener consisting of a bolt 35 passing through a boss 36 on one of the plates, the opposite plate having a conical recess in which a portion of the nut 37 may engage. Figure 12 shows still another form of fastener in which a bolt 38 has a bent portion 39 serving as its head and being provided with a threaded portion 40 which may be engaged by a tool, such as 41, by which it may be pushed into position from one side of the set of boiler tubes. Then, the key 42 is driven in posi-v tion and the tool 41 released by unscrewing it from the threads 40.

In the form of my invention shown in Figures 13 to 16. inclusive, I have indicated a method by which the number of plates, which would be required in the forms of my invention heretofore described. may be considerably reduced. In practice, however, it will not be desirable to make the plates large enough to engage a very considerable number of tubes,,because of the manufacturing diiliculty in making the plates so that each of the tubes will have a close thermal contact with the plate. In the form shown in Figures 1.3 and -14, I have shown a plate which is substantially a quadrilateral of considerably greater length than width, and with appropriate recesses along its end faces to engage the tubes in the manner which I have already described, and with portions extending somewhat beyond the line of centers of the tubes so as to provide 0v rlapping portions between the adjacent plates. into which fastening devices may be passed. Such a plate 43 engages three of the tubes 10 at its top and three at the bottom and one at either end. In the form shown in Figures 15 and 16, the plates 1 1 instead of extending generally parallel to either a horizontal or a vertical row of tubes, as do the plates 43 of Figure 18. extend gen erally diagonally across the rows of tubes, but. otherwise are substantially the same in character as the plates 43. The plate-ill eugages two tubes on its top and two tubes on its bottom and one on either end. In the form shown in Figure 15, because of the necessary relative position of the plates, some of the plates, such as 45, will be formed with a pad 4L6 to fill up the space between the plates i l and 45. The fastening members, such as the bolts 31, will pass through the plates in the usual manner including the pad 46, where such a pad is necessary, these fastening members being drawn tight by any suitable means. such as the nuts 32.

It will be noted that in the form shown in 2 and 8, the recesses at the sides of the plates 21 are deeper than the recesses at the top and bottom. It is understood, of course, that according to my invention, it is desirable to have as extensive a contact between the edges of the plate and the water tubes as is possible and still permit the plates to be gotten into place. lVhen, however, the plates are inserted the plates will be rotated practically on their vertical axes and this will necessitate spreading the tubes above and below the plates suliicient to permit the projecting upper and lower corners of the plates to pass such tubes. On the other hand. the tubes at the side need be spread only suliicient to permit the diagonal from the front part of the plate on one side to the rear of the plate on the other side to pass the tubes. Consequently, I can make the plates in the manner shown in Figs. 2 and 8 and preferably do so to get the maximum contact with tubes.

After the plate is in its final position, the fastening; means may be inserted and drawn up to bring the plates together and lock them in final position. As one convenient means of inserting the .torms of fastener shown in Figures t and 5. I mav use the tool shown in Figures 17, 18 and 19. The tool shown in Figure 19 is an arrangement for holding the head of the bolt 22. and is pro vided with a lone tubular handle 52 with a fixed jaw 53, opposed to which is a movable jaw 54 mounted on a rod extending through the tube 52 and movable lengthwise therein by means of the wine; nut 56. The head of the bolt 22 is clamped in the jaws and 54 and the tool, with the bolt in place, passed through the aisles of the tube. until the bolt is opposite the holes in the plates, into which it is then passed.

In order to insert and lock the hey-like otter-pin 23, I provide the tool shown in "'ogures 17 and 18, which is made up of a tubular handle 57 having a wedgethereto. llhroug'h J shaped jaw 58 attached 7 the tub 57 extends a rod 59 threaded as at 60 and being provided at its opposite ends with a holoing formed of a fixed abutment (31 and a spring member 62, the latter being recessed, as at 6 to pass over the rivet which connects the two legs of the l: y A wheel nut (3 1 engages the threads (it), whereby the key holder, formed of the members 61, (32 and the wedged jaw 58, may be drawn together to separate the legs of the hey 23 to loci: it in position.

Vith the tool outside ot' the boiler tubes, the nut (r-l is manipulated until the heyholding; j; s and the jaw '35. are widely separated, the tube 57 being also rotated to bring; the jaw .38 to the dotted line position shown in Figure 18, the pin 1 in the rod 59 passing into a slot to lock the jaw in this pos.;ion. The key 23 is then slipped beneath. the spring 62 and the tool passed through one of the aisles of the tubes until the end of the he 23, the legs of which at this time are close together, is opposite the slot in the bolt 22. Then, the tool is drawn toward the operator to drive the key 23 through the slot of the bolt. which, by reason of its angled surface, will act to draw the bolt tightly against the plates 21. The tube 57 is rotated so that the pin G l passes through the slot 66 and stands opposite the slot 67. Then, the nut 24 is rotated to force the jaw 58 toward the abutment (31, the wedge of this jaw passing between the legs of the key 23 to separate them in the manner shown in Figure 18.

It will be noted that I have arranged the fastening devices for the plates in the aisles of the tubes, and consequently, it any other form of fastening device than that which I have just described is used, it may be insert ed and fastened by the use of suitable tools adapted to that particular term or" fastener. For instance, the form or fastener shown in gure 12 may be lllSQl'LQCl in a manner similar to that just described, except that the tool ll is specially adapted for the type of bolt 38. The key 12 may be driven and locked with the tool which I have just de scribed.

When bolts 01 ordinary construction, such as shown in Figures 9 and 11, are used, they are to be carried by suitable holders and inserted in the openings, and the nuts will be placed therein and rotated to draw the bolts up by suitable specific long handled tools which may be operated from the exterior of the bank of tubes.

lVhile I have illustrated my invention in connection with a cross battle, it will be understood that the invention may also be applied to battles which extend parallel to the tubes. In such case, the circular recesses will be parallel instead of at rightangles to the race of the plate forming part of the face of the battle, such recesses being formed accurately so as to lit closely around the tube and in close contact therewith. vSuch plate may be formed with overlapping portions through which fastening members may pass, or the plates may be otherwise connected to each other or to the tubes then'iselves.

As a convenience in manufacture. l pie for to make the plates liat, but it will be obvious that, if desired, they may be formed with ollsets at the overlapping portions, so that the main portions of all ot the plates will be in the same plane.

I claim 1. A cross battle for a water tube boiler having a plurality of paralleltubes arranged in rows in staggered relation, said ballle comprising a plurality of relatively thick metallic plates substantially quadrilateral in outline and having a single circular recess in each of the tour end faces and the wall of each recess fitting; closely against and around a water tube for substantially the full width of the face.

2. A cross baffle for a water tube boiler having a plurality of parallel tubes arranged lit") in rows in staggered relation, said bafiie comprising a plu 'ality of relatively thick metalic plates substantially quadrilateral in outline and having a single circular recess in each of the four end faces and the wall of each recess fitting closely against and around a water tube for substantially the full width of the face, each plate overlapping a portion of each of four adjacent plates to form a continuous ballle extending across the tubes.

3. A cross baffle for a water tube boiler having a plurality of parallel tubes arranged in rows in staggered relation, said baflle con'iprising a plurality of relatively thick metallic plates substantially quadrilateral in outline and having a single circular recess in each of the four end faces and the wall of each recess fitting closely against and around a water tube for substantially the full width of the face, each plate over lapping a portion of each of four adjacent plates to form a continuous halite extending across the tubes, and said plates being connected at the overlapping portions.

4. A cross baffie for a water tube boiler having a plurality of parallel. tubes arranged in rows in staggered relation, said battle comprising a plurality of relatively thick metallic plates substantially quadrilateral in outline and having a single circular recess in each of the four end faces and the wall of each recess fitting closely against and around a water tube for substantially the full width of the face. each plate overlapping a portion of each of four adjacent plates to form a continuous baffle extending across the tubes, and a fastening member connecting the adjacent plates through the overlapping portions.

5. A. cross battle for a water tube boiler having a plurality of parallel tubes arranged in rows in staggered relation, said baffle co1nprising a plurality of relatively thick metallic plates substantially quadrilateral in outline and having a single circular recess in each of the four end faces and the wall of each recess fitting closely against and around a water tube for substantially the full width of the face, each plate overlap' ping a portion of each of four adjacent plates to form a continuous baffle extending across the tubes, and a fastening member connecting the adjacent plates through the overlapping portions and located in the diagonal aisles formed by the tubes.

6. A cross bailie fora water tube boiler having a plurality of parallel tubes arranged in rows in staggered relation, said battle comprising a plurality of relatively thick metallic plates substantially quadrilateral in outline and having a single circular recess in each of the four end faces and the wall of each recess fitting closely against and around a water tube for substantially the full width of the face, each plate over lapping a portion of each of four adjacent plates to form a continuous bafiie extending across the tubes, two of said adjacent plates being on one side of the plate and the other two adjacent plates onthe opposite side of the plate.

7. A cross batlie for a water tube boiler having a plurality of parallel tubes arranged in rows in staggered relation, said baffle comprising a plurality of relatively thick metallic plates substantially quadrilateral in outline and having a single circular recess in each of the four end faces and the wall of each recess fitting closely against and around a water tube for substantially the full width of the face, each plate overlapping a portion of each of four adjacent plates to form a continuous baflle extending across the tubes, two of said adjacent plates being on one side of the plate and the other two adj acent plates on the opposite side of the plate and said plate being connected at the overlapping portions.

8. A cross battle for a water tube boiler having a plurality of parallel tubes arranged in rows in staggered relation, said baffle comprising a. plurality of relatively thick metallic plates substantially quadrilateral in outline and having a single circular recess in each of the four end faces and the wall of each recess fitting closely against and around a water tube for substantially the full width of the face, each plate overlapping a portion of each of four adjacent plates to form a continuous baffle extending across the tubes, two of said adjacent plates being on one side of the plate and the other two adjacent plates on the opposite side of the plate and said plates being connected at theoverlapping portions, and a fastening member connecting the adjacent plates through the overlapping portions.

9. A cross bafiie for a water tube boiler having a plurality of parallel tubes arranged in rows in staggered relation, said baflie comprising a plurality of relatively thick metallic plates substantially quadrilateral in outline and'having a single circular recess in each of the four end faces and the wall of each recess fitting closely against and around a water tube for substantially the full width of the face, each plate overlapping a portion of each of four adjacent plates to form a continuous baiile extending across the tubes, two of said adjacent plates being on one side of the plate and the other two'adjacent plates on the opposite side of the plate and said, plates being connected at the overlapping portions and a fastening men'iber connecting the adjacent plates through the overlapping portions and located in the diagonal aisles formed by the tubes.

10. A cross battle for a Water tube boiler,

comprising a plurality of relatively thick metallic plates substantially quadrilateral in outline and having a circular recess in each of at least two opposite end faces, and the wall of each recess fitting closely against and around a water tube for substantially the full width of the face, a portion of one of the side faces of each plate overlapping a portion of a side face of an adjacent piece, to form a continuous baffle extending. across the tubes, and bolt-like fastening members passing through the overlapping portions and connecting the adjacent plates, the bolts having tightening means constructed and arranged to draw the faces of the plates together when the tightening means is moved at right angles to the axis of the bolt.

11. A cross baffle for a water tube boiler having a plurality of parallel tubes arranged in rows in staggered relation, said baflie comprising a plurality of relatively thick metallic plates substantially quadrilateral in outline and having a circular recess in each of at least two opposite end faces and the wall of each recess fitting closely against and around a water tube for substantially the full width of the face, a portion of one of the side faces of each plate overlapping a portion of a side face of an adjacent plate, to form a continuous baiile extending across the tubes and fastening members connecting the adjacent plates through the overlapping portions and located in the diagonal aisles formed by the tubes and bol=t-like fastening members passing through the overlapping portions and connecting the adjacent plates, the bolts having tightening means constructed and arranged to draw the faces of the plate together when the tightening means is moved at right angles to the axis of the bolt. 12. A cross battle for a water tube boiler having a plurality of parallel tubes arranged in rows in staggered relation, said bafile comprising a plurality of relatively thick metallic plates substantially quadrilateral in outline and having a single circular recess in each of the four end faces and the wall of each recess fitting closely against and around a. water tube for substantially the full width of the face, each plate overlapping a portion of each four adjacent plates to form a continuous bafiie extending across the tubes, and bolt-like fastening members passing through the overlapping portions and connecting the adjacent plates, the bolts having tightening means constructed and arranged to draw the faces of the plates toget-her when the tightening means is moved at right angles to the axis of the bolt.

13. A cross battle for a water tube boiler having a plurality of parallel tubes arranged in rows in staggered relation, said bafile comprising a plurality of relatively thick metallic plates substantially quadrilateral in outline and having a single circular recess in each of the four end'faces and the wall of each recess fitting closely against and around a water tube for substantially the full width of the face, the recesses in two opposite end faces being relatively deep and the recesses in theremaining two end faces being relatively shallow. 1%. A cross baflle for a water tube boiler having a plurality of parallel tubes arranged in rows in staggered relation, said battle comprising a plurality of relatively thick metallic plates substantially quadrilateral in outline and having a single circular recess in each of the four end faces and the wall of each recessfitting closely against and around a water tube for substantially the full width of the face, each plate overlapping a portion of each of four adjacent plates to form a continuous baflle extending across the tubes, the recesses in two opposite end faces being relatively deep and the recesses in the remaining two end faces being relatively shallow.

15. A cross baffle member for water tube boilers comprising a metallic plate having a plurality of circular recesses in its edges, each adapted to fit closely against the surface of a tube, the plate being adapted to be forced between a group of four spaced tubes whose lines of centers form a rhomboid, to produce a close thermal contact between the wall of a recess of the plate and one of the tubes over'a relatively large area having a width the same as the thickness of the plate.

16. A cross ballie member for water tube boilers comprising a metallic plate having a plurality of circular recesses in its edges, each adapted to fit closely against the surface of a tube, the plate being adapted to be forced between a group of four spaced tubes whose lines of centers form a rhomboid to produce a close thermal contact between the wall of a recess of the plate and one of the tubes over a relatively large area having a width the same as the thickness of the plate, the plate having portions extending beyond the lines connecting the centers of the tubes.

ISAAC HARPER.

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