US2150927A - Porous plug for staybolts and the manufacture thereof - Google Patents

Description

March 21, 1939. w. T KILBORN ET AL 2,150,927'

POROUS PLUG FOR STAYBOLTS AND THE MANUFACTURE THEREOF Filed April 30, 1936 4 QW V INVENTORS will 0 Patented Mar. 21, 1939 2,150,927

UNITED STATES PATENT OFFICE POROUS PLUG FOR STAYBOLTS AND THE MANUFACTURE THEREOF William T. Kilborn, Pittsburgh, and Frederick K. Landgraf, Crai'ton, Pa., assignors to Flannery Bolt Company, Bridgeville, Pa., a corporation of Delaware Application April 30, 1936, Serial No. 77,186

Claims. (Cl. 85-15) This invention relates to the porous bodies or to the severe operating conditions of the boiler, plugs which are used in the firebox end of staythere is also added the jarring and vibration unbolts to close the opening in said bolts, and to a avoidably incident to operating over rail Joints, method of making the same. switches, etc.

5 In many boiler installations, it is desirable to It would be impractical to separately cement 5 use hollow staybolts. All steam boilers in service each plug in a hole, because it would have to be must periodically be inspected to ascertain if any done with care and require skilled labor, and of the staybolts are broken and whether the boiler thereby increase the cost of installation. Also is safe for its prescribed pressure. Where hollow there would be danger that any satisfactory ad- 'staybolts are used, this inspection is made by hesive might obstruct the porosity of the mate- 10 cleaning and testing the holes in all of the stayrial so as to render it substantially impervious to bolts to determine that they are clean and open the passage of water therethrough. throughout the length of the hole, and then plac- The present invention contemplates a plug and ing the boiler under hydrostatic pressure. If any a method of treating the plugs wherein the surhollow staybolts are broken or even fractured so face of the plug is provided with a material which 15 that the fracture extends into the hole, the appliincreases the cohesion between the pl a d t cation of hydrostatic pressure to the boiler will inner wall of the tell-tale hole. According to the cause water or moisture to appear in the holes. pr en nv it i mpl h the amount of water, of course, depending on the other material be applied to the porous body extent of the break or fracture. If the holes in which will not lessen the resistance of that body 20 the staybolts are not clean the evidence of leak-- to ea pa the Porosity thereof but which age may not be detected, the accumulation of will increase the cohesion between the porous madeposit on the inside of the hole absorbing or terial and the walls of the hole. closing off the flow of water, particularly where The invention may be readily understood by the fracture is quite small. In some cases, the reference to the accompanying drawing, in 26 so-called tell-tale hole extends throughout the which: full length of the bolt. In other cases, it extends Figure 1 discloses a typical flexible staybolt throughout the major portion of the length and assembly having a plug at the firebox end of the not entirely through the bolt. It is good practice hol the plus being t at d n a rda t 30 to drive porous plugs into the holes from the firethe present invention; and 3 box end of the bolts when the boiler is ready to Figure 2 is a perspective view of one of the be put into service. These porous plugs, one form P ugs ma e in accordance With the Present invenof which is shown in prior United States Patent tion.

No. 1,428,541, dated September 12, 1922, serve to According to the present invention, the porous prevent foreign matter from entering the hole plugs are manufactured according to any well I from the firebox end of the boiler and filling it known method. When the manufacture of the up. At the same time, the plug, being porous, plugs is otherwise completed, including the firing will permit the escape of steam and/or water of the bonded granular material of which they therethrough if the staybolt subsequently fracare composed, and the shaping, a suitable sizing tures. compound, paste or other form of substance is 40 The material used for making the porous plugs applied to the plugs-and completely dried theremust be heat-resisting as well as porous. The on. The sizing or other substance employed bonded granular abrasive material which is genmust be of a character which will not destroy erally used for the purpose must have a bond of the porosity of the mass. It must be of a charsuch character that the plugs will not disintegrate acter which will dry out thoroughly, and must 45 when they are subjected to the temperature of be of a character which will leave, when dried, the inside of the firebox. Since the bond is com a deposit on the outside of the plug capable of pletely fused in the forming of the plug, the only increasing the cohesion between the plug and the inherent means for holding the plug in the end of inside oi the hole.

the bolt is friction. It has been found in use As a typical example, the plugs after they are 50 that some plugs hold satisfactorily, whereas otherwise ready for use, are immersed in a soluothers will drop out, even though appartion of a waterglass, such as sodium or potassium ently tight in the first instance, after the boiler silicate. The porous material absorbs the waterhas been used for a period of time. This is esglass solution. The plugs are then dried. When pecially so in locomotive boilers where in addition the plugs are dry a very thin deposit of the 5| 10' rial alone'is relied upon. This has not only been borne out in actual use, but has been borne out on specially constructed test panels, such panels .having a large number of staybolts mounted thereon. Arrangements are provided for heating and cooling the paneland an'air hammer is provided for vibratingthe panel. Throughthis arrangement, conditions simulating firebox conditions can be obtainedbut of a morefintensified' order. It. been fo'mid that-porous plugs processed asdescribed above, will remain inthe holes on the test panel under conditions which result infia very great percentage, of the untreated plugs jarring out. To the eye', however, 'the treated plugs do not differ in appearance from the untreated ones. the amount of. silicate Moreover, the plugs so deposit belnl slllht. treated can bebmlc'en, out of the holes for inspection purposes where necessary as readily as the untreated onea 'there beingno actual adhesion or cementingsof the plus to the'interior of the hole.

- While the water-soluble silicates make the best material so far. aawrexperlmeatsu it the present time have other materials mayalso be For example, the plugs maybe immersed-"in a solution and dried=,-before use. In the subsequent operation of a boiler, the

sugar but the resulting film ofzcarbon neverthelessserves to increase the cohesion between the plug and the walls of the'hole into which the plug'is driven. Likewise, other organic materials may be used which will also carbonize as, for a thin solution of gum-tragecanth. solution of ordinary table salt or sodiumchloride may-also'beused. the glaze- ,formingj quality of the salt being utilized. Various ceramic slips or compositions'may also be used. The foregoing are merely typical of a great many other materials which. maybe used. The material used must be either dusted onto the exterior of the porous body or if used as a solution must be of a character which will not upon soaking into the porous material, render the same non-porous. The plugs areof relati'vely small diameter, and hence care must be taken that the material used, if it soaks into the body of the material will not destroy or seriously impair its porosity. I

In the drawing. .2 designates a typical hollow staybolt having a tell-tale hole 3 opening at the firebox end and having a plug 4 driven intofthe end thereof, the plug beingof a character herein described. In Figure 2, the plug 4 is shown detached from the staybolt. It is preferably slightly tapered to facilitate its being entered into the hole of the staybolt and driven in.

The material used for treatingthe plugs mus be a material which can be dried so that the plugs after being-manufactured and treated, can

be shipped in a dry state to the user. a

It will be understood that various changes and modifications may be made in the invention within the scopeof the following claims.

We claim: A l. A porous plug for staybolts comprising a refractory body of a porous chai acte'r having a surface coating of a materialthereon of a glazelik e nature for increasing the frictional'co'ntact ,between the plug'and the wall of the hole in the v 2. Aporou's plug for staybolts comprising a refractory body of'a" porous characterhaving .a

water-soluble silicate applied to the outer'surfaces thereof; 3. A porous plug foista' fractory body of a ro "its comprising a rethe porosity of the plug a whole and which increases the cohesion between the plug and the hold of the staybolt into which the plug is entered. r

4. The method. of treating porous plugs'for use in closing the telltalaholes of, boiler staybolts character having a dried coating formihg a surface film thereover of alcharacter which does not detrimentally' affect which comprisesimmersing the plugs in a solu-" tioncapable of leaving afdepositon the porous materiaiof a character-which increases the cohesion between'the plu'g and thehole into which the plug is drivenbiitwhich does not appreciably affect the porosity of theplug. Q

5. Themethod of treating. porous plugs for use in closing the telltale holes'lof' boiler. ,staybolts which comprises immersing the plugs ,in a so1ution of a water-soluble silicate'and thereafter drying the plugs. v V

mores.

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