US2216351A - Blowout plug - Google Patents

Description

Oct. 1. 1944). I M. G ..'MILLER BLOWOUT PLUG Filed Feb. 24, 1959 MEL w/v G. M/LLEB Patented Oct. 1, 1940 t. BLOWOUT PLUG Q I 4 Claims.

This invention relates to a blowout plug and has more particular relation to a novel type of insert adapted to be readily inserted into the jacket of the plug when necessary.

The plug has been particularly designed for use in boilers. The complete assembly embodies a jacket designed to be screwed upwardly through the crown sheet of the boiler furnace and having an insert or filler of fusible material which, in .case the water becomes too low in the boiler, will fuse and drop out allowing steam to enter the furnace to extinguish the fire and to prevent an explosion.

15 The usual blowout plugs, as at present constructed, comprise a metal jacket adapted to be screwed through the crown sheet of a furnace and filled from end to end with a fusible material such as tin or lead designed to melt and drop out in case the water becomes too low. For safety 20 these plugs are changed from time to time for the reason that after they have been installed for a considerable length of time the corrosion of the jacket may prevent the fusible filler from melting and dropping out as it is designed to do, and it is .common practice to remove the plugs and replace them from time to time. In as much as the conventional type of plug is filled from end to end with a fusible material, it is not practicable to remove said material and reuse the jacket and hence there is considerable loss in discarding the plugs in as much as the complete plug, including the jacket, must be discarded.

It is one of the prime objects of this invention to provide a novel type of filler for the jacket which, when it is desired to renew a plug, may be removed from the jacket and a new one substituted so that the jacket may be reused indefinitely, thus resulting in a great saving.

With the above and other objects in view, the

4 invention has particular relation to certain novel features of construction, arrangement of parts and use, an example of which is given in this specification and illustrated in the accompany- 45 ing drawing, wherein:

Figure 1 shows a longitudinal sectional view of the plug embodying the invention and showing the same in position in the crown sheet, and

Figure 2 shows aside view of the filler or in- 50 sert designed to close the bore through the jacket.

Referring now more particularly to the drawing wherein like numerals of reference designate the same parts in each of the figures, the numeral 1 indicates the jacket of the plug which is to somewhat longer than the jacket of the standard V i flM elvin G. Miller, Houston,Tex. I I 'Application February 24, 1939, Serial No; 258,142 1- (011122-5043) plug commonly used. At one end the jacket is formed with a polygonal head 2 to receive a wrench whereby the jacket may be screwed through the threaded aperture 3 of the crown sheet 4. The jacket has the external threads 5 which mesh with the threads of the aperture 3 as shown in Figure 1. The jacket has an axial bore 6 extending therethrough from its outer to its inner end and of an approximately uniform diameter. However, the bore is slightly flared at its inner end as at I.

The numeral 8 designates an insert or plug formed of fusible material such as tin or other suitable fusible material.

Before insertion into the jacket, the plug 8 is approximately frusto-conical in form but at its large end it is flared at a slightly greater pitch, than the flare of the main body of the plug as is indicated at 9, Figure 2. The diameter of the plug 8 adjacent the flared portion 9 is slightly greater than the diameter of the bore 6 adjacent the fiared portion 1 so that when the plug 8 is driven into the inner end of the jacket, a portion of said plug as Ill will assume a true cylindrical shape and when the plug is driven to home position the flared portion 9 will be fitted very closely into the seat 1 so that there will be no leakage of water between the filler or plug 8 and the jacket I and hence no corrosion will collect between the filler plug and the jacket to prevent the plug from melting and dropping out in case of excessive heat.

When it becomes necessary to renew the plug the jacket may be screwed out of the crown sheet and the filler plug 8 knocked out and a new one substituted for it and the jacket may thus be used from time to time with substantially no loss of material.

It will be noted that only a relatively small amount of material is required for the plug 8 since it closes only the inner end of the jacket and hence said plug may be very cheaply produced and readily supplied to the users for replacement purposes as necessity may require.

The drawing and description disclose what is now considered to be a preferred form of the invention by way of illustration only, while the broad principle of the invention will be defined by the appended claims.

What I claim is:

1. A blowout plug comprising an outer jacket having an axial bore of approximately uniform diameter extending therethrough from end to end, a fusible filler plug adapted to be inserted into one end only of the bore, said filler plug tapering from its outer to its inner end and the margin, only, of the outer end thereof being slightly flared to form an annular fluid tight joint with the jacket when driven home into the jacket.

2. A blowout plug comprising an elongated jacket having a cylindrical bore of approximately uniform diameter extending axially therethrough, from end to end, a fusible insert, approximately frusto-conical in form, inserted into one end only of the jacket, the outer end of the insert being slightly flared and a portion of the insert adjacent said flared end being deformed into a cylindrical shape to form a fluid tight joint with the jacket when the insert is driven home.

3. An insert for the jacket of a fusible plug, said insert being formed of fusible material and being frusto conical in form and having its large end slightly flared at the margin only of said large end.

4. A blowout plug comprising an elongated outer jacket having a cylindrical bore of approximately uniform diameter extending axially therethrough from end to end, a fusible filler plug approximately frusto-conical in form adapted to be inserted into one end only of the bore, said end of said bore being annularly! .chamfered and the corresponding marginal end of the filler plug being flared, said filler plug having a portion adjacent the flared end deformed into a cylindrical shape and fitting closely in the bore and said flared end fitting closely in the chamfered portion of the bore, when the filler plug is driven fully home into the bore, the cylindrical portion and the flared portion of the plug forming a fluid tight joint with the jacket.

7 MELVIN G. MILLER.

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