US1101084A - Boiler-plug. - Google Patents

Description

- partly in elevation.

UNITED STATES PATENT OFFICE,

EUGENE J. MCCABTY, 0F CLINTON, MASSACHUSETTS, ASSIGNOR TO MAX MACHINE COMPANY, OF CLINTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

BOITIER-PLUG.

Speicicaton of Letters Patent.

Patented J une 23,1914.

I. Application filed April 3, 1911. Serial No. 618,525.

To all whom yit lm ay conce/rn:

Be it known that I, EUGENE J. MoCiiirrY, a citizen of the United States, residing at Clinton, in the county of Worcester and State of Massachusetts, have invented new and useful Improvements in Boiler-Plugs, oi' which the following is a specification.

My invention relates to boiler plugs, and its objects are to provide an eil'ective means of closure for the ends of boiler tubes or dues, and to prevent the blowing out of Said closure means under the conditions of actual ilse. v

My invention consists in constructing a boiler-plug in the form of a cup shaped disk, the walls of which are concaved or taper outwardly for the purpose of permitting the plug tobe readily introduced within a boiler tube normally of a slightly smaller interior diameter than the largest exterior diameter of the plug.

My invention further consists in the improvements and novel arrangement opai'ts more particularly hereinafter pointed out and claimed.

Attention is hereby7 directed tothe d rawing in which similar numerals of designation refer to similar parts throughout the several views.

Figure l is a horizontal section of myimproved plugafter it has been duly installed, showing the boiler tube partly in section and Fig. 2 is a section sinnlar to Fig. 1, but showing in an exaggerated. forni` for the purposes of illustration, the annular groove in the wall of the-plug before it has been expanded into the positionl shown in" Fig. l.

Referring to the drawing; the plug 3 is composed ot' metal, and may be rolled, turned, cut, or cast in the form here shown. In the wall 4 of the plug is an annular recess which is extremelyy shallow, andl is preferably concave. My primary purpose in having this recess is to prevent any portion of the wall 4 Jfrom coiningin Contact with the boiler tube while plug is being installed except the portions 6 andv 7, which when both are at the same vtemperature are slightly greater in diameter than the interior diameter of the boiler tube 8. Preferably this difference in diameter is the exact depth of the recess 5.

I prefer. to introduce my plug While cold into the end of the boiler tube 8 while the same i s hot, preferably while it is still under the influence of the steam of the boiler while iny use in order that when my plug expands with lthe heat, the walls ot' the plug and tube will com@ int() Close contact and the recess 5 will be eliminated as shown in Fig. l. To accomplish this result, itis necessary that the annulairecess be of merely sufficient depth to just prevent the said walls from touching,-`-a microscopic variation being all k that is i'iecessaiy or desirable. Such propor` tions are Inot readily observa-ble with the naked eve, and would exist within the width of the line of separation or' tliewalls shown in Fig. l; the exaggerated recess 5` shown in Fig. for the purposes of illustration not being desirable in my preferred form of construction, though within the scopel of my invention. This method of construct-ion differs essentially from shrinking, as the term' is commonly used, since theplug is designed to be introduced not only when the boiler is being made but also after the same has been piitiinto actual use; the heat produced by the boiler being sufficient for @HUS- ing the walls of in v plug and tube to come.' in Contact upon the expanding ot' the material of which the plug is composed.

In some cases it may be`fouiid convenient to construct my plug tapering outwardly, that is, with the diameter of the plug be- Icoming graduali)7 smaller away from the portion 3. But in such ease care should bc taken to have the 'taper ot' the same microscopic dimensions as that ot' the annular recess 5 above described in order that the walls may just clear when the plug is first installed in position. Since it is my purpose in the preferred form of my invention merely to have sufficient ot' the surface ot' the plug to come iii contact with the tube in order that. the two may be wedged together without splitting the tube, and to have all other parts vot' the wall ot thel plug .separated iii the slightest degree from ,the wall of the tube while installation is taking place, I desire to include as within uiy invention any form of plug embodying these features no mattei' how the recesses are formed or situated.

Through the use of my improved construction, I am able at an instants notice to install one of my plugs in any boiler tube even where anold form of plug has been used. In the construction now on the market it is common practice to use plugs which are cast-- solid and driven into the tube without expanding; Such a method of connection is objectionable for the reason that it is hard to make a tight joint and is liable to blow out. Since my plugs are all made in standard sizes with expansion metal they may be rolled or expanded with a tool ot' the same style as is used to roll or expand the tubes and thus form a greater diameter back of the boiler head by outward pressure on thel tube; it would then be impossible with very high hydraulic pressure to start these plugsy slstng in inserting the plugwhile cold into a the tube while the tube is expanded by heat and keepingthe tube heated until the plug has become heated to the same temperature as the tube, the plug having a plurality of diameters, the inner one of which when cold lits the bore of the heated tube with a wedgl ing lit and the outer end of which when cold is minutely smaller than the bore ot' the heated tube, whereby when it thus becomes heated to a temperature equal to that of the tube it Will have become expanded sufficiently to cause it to become permanently locked in 'the tube and have a continuous contact with the inner face of the tube throughout its outer or peripheral surface.

2. The method herein described of plugging the ends of boiler tubes consisting in inserting the plug while cold into the tube While the tube is expanded by heat and keeping the tube heated until the plug has bel come heated to the same temperature as the tube, the diameter of the plug at its inner end being such that when thus inserted in a cold state it will have a wedging fit in the bore of the heated tube while the diameter of the plug throughout the larger part of its length is minutely less than the interior diameter of the tube, whereby when it thus becomes heated to a temperature equal to that ot' the. tube it will have become expanded sufficiently to cause it to become permanently locked in the tube and have a continuous contact with the inner face of the tube throughout itsI outer or peripheral surface.

3. The method herein described of plugging the ends ot' cylindrical boiler tubes consisting in inserting a hollow plug while cold iuto the tube while the tube is expanded by heat and keeping the tube heated until the plug has become heated to the same temperature as the tube, the diameter of the plug at its outer and inner ends being such that when it thus becomes heated to a temperature equal to that of the tube said outer and inner ends will hare become expanded sulticiently to cause it to become permanently locked in the tube, and the diameter of the plug intermediate said ends being minutely less than at said ends.

ln testimony whereof I have hereunto set my hand in presence of two subscribing witnesses, this 30th day of March, 1911.

EUGENE J. BCCARTY.

1Witnesses:

THOMAS J. MCNAMARA, lYiLLIAM H. DIETZMAN.

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