Improvements in Tube or Stay Fastenings for Steam Boilers or Condensers or other Pressure or Vacuum Receivers.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in Tube or Stay Fastenings for Steam Boilers or
Condensers or other Pressure or Vacuum Receivers.
I, CHARLES DowSEN, of 21, Croft Terrace, Jarrow-on-Tyne, Mechanical Engineer,
do hereby declare the nature of this invention to be as follows:
-
In this invention the hole in the tube plate or shell of receiver is tapped with
a thread having a diminishing diameter at the bottom, an annular plug of parallel
thickness is screwed on the outside to fit the thread in the hole it is then placed
on the plain end of the tube or stay and screwed down to the bottom of the hole
causing the plug to contract and closely grasp the tube or stay, or the bottom of
the hole in the plate or shell may be formed without thread but made of conical
or curved form the end of the annular plug of similar shape is screwed down
causing it to contract in diameter and closely grasp the tube or stay.
Dated this 22nd day of June 1897.
CHARLES DOWSEN.
Improvements in Tube or Stay Fastenings for Steam Boilers or
Condensers or other Pressure or Vacuum Receivers.
I, CHARLES DOWSEN, of 21, Croft Terrace, Jarrow-on-Tyne, do hereby declare the
nature of this invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :-
--
This invention relates to tube or stay fastenings of the kind in which there is
interposed between the tube or stay to be fastened and the tube plate or shell an
annular plug that is screwed on the outside to fit a thread in a hole in the tube
plate or shell made at one end for a part of its length of gradually diminishing
diameter (see for example my Patent Specification No. 9741 of 1897).
The accompanying drawings illustrate my present invention.
Fig. 1 shows a sectional view of part of a tube plate or shell, part of a tube or
hollow stay, and the interposed annular plug.
The hole in the tube plate or shell a is for the greater part of its length drilled
of equal diameter and that portion of it is tapped with a thread. The remaining
portion which I call, for distinction, the bottom of the hole, (and which is marked
in the drawings) is formed without thread, but made of conical form (Fig. 1) or
curved form (Figs. 2 and 3). The annular plug b is of parallel thickness for most
of its length, and at that part is screwed on the outside to fit the thread in the
hole; but the end of the plug is made without thread and of a similar shape to the
reduced end of the hole; it is placed on the plain end of the tube or stay c and is

page_text: screwed home so that its end enters the bottom of the hole, causing the plug to
contract in diameter and closely grasp the tube or stay. There may be a fine saw
cut (or more than one) in the smaller end of the tube, so that it may the more
readily contract. Or the tube may be of metal, such for example as yellow brass
or white metal sufficiently soft to adapt itself to the form of the annular space
between the wall of the diminishing part of the hole and the exterior of the tube.
When such metal is used, it may sometimes not be necessary to previously reduce
the external diameter of the annular plug.
By making the hole with a part of diminishing diameter that is not screw
threaded I am enabled in practice to effect considerable economy in the effectual
fastening of tubes as set forth.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is:―
Fastening a tube or stay in a steam boiler condenser, or other pressure or vacuum
receiver tube plate or shell by means of an annular plug surrounding the tube or
stay, and screwed into a hole which is tapped for a part of its length only and at
its one end for a part of its length is formed without thread but made of conical
or curved form the annular plug surrounding the tube or stay being screwed into
the hole so as to cause the end of the said plug to enter the plain (unthreaded)
part of the hole and to contract in diameter therein and closely grasp the tube or
stay as shown in and described with reference to the accompanying drawings.
Dated this 17th day of February 1898
For the Applicant,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.