IMPROVEMENTS IN TUBULAR AND TUBULOUS STEAM BOILERS
Year: 1882

page_text: LETTERS PATENT to Alfred Fernandez Yarrow of the firm of Yarrow and
Company of the Isle of Dogs Poplar in the County of Middlesex for an
invention of "IMPROVEMENTS IN TUBULAR AND TUBULOUS STEAM BOILERS."
PROVISIONAL SPECIFICATION left by the said Alfred Fernandez Yarrow
at the Office of the Commissioners of Patents on the 4th May 1882.
ALFRED FERNANDEZ YARROW of the firm of Yarrow and Company of the Isle
of Dogs Poplar Shipbuilders "IMPROVEMENTS IN TUBULAR AND TUBULOUS STEAM
BOILERS
"
My Invention has for its object to prevent leakage of the tubes of Steam boilers
in the tube plate.
Great difficulty has hitherto been found in keeping the tubes tight in tube plates
when fixed therein in the usual manner that is by boring holes in the plate and
inserting the tubes therein after which they are expanded The cause of the
difficulty I believe arises in some cases from the distortion of the tube plates and
the consequent distortion in the shape of the holes and this is more particularly
found to be the case when the tube plates are subject to large fluctuations in
temperature such as for example in boilers for Torpedo-boats.
Although the before described method of inserting tubes in tube plates is the
customary system tubes have been frequently screwed into tube plates but not in
such a manner as I now propose and by which means I hope to overcome the
hereinbefore mentioned defect.
According to my Invention I form both in the holes in the tube plate and on the
tube where it is screwed into the tube plate screw threads of such a nature that
both surfaces of the thread are parallel with one another such for example as is
the case with a square thread, by which means it is evident that although the tube
hole may get enlarged or distorted into an oval or otherwise in shape the flat
surfaces of the thread of the tube and the thread of the tube plate will still
remain in close contact thereby preventing the leakage of the water between the
tube and tube plate Or the thread in holes in the tube plate and on the tubes of
a dovetail like section so that the threads lock together and when the hole in the
tube plate gets enlarged or distorted into an oval or otherwise it forces the tube to
become similarly distorted or enlarged whereby the tube continues to be in close
contact with the tube plate throughout its entire circumference, and prevents
leakage.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alfred Fernandez Yarrow in the Great Seal Patent Office on the
1st November 1882.
ALFRED FERNANDEZ YARROW of the firm of Yarrow and Company of the Isle
of Dogs Poplar in the County of Middlesex "IMPROVEMENTS IN TUBULAR AND
TUBULOUS STEAM BOILERS
"
My Invention has for its object to prevent leakage between the tubes and tubo
plates of tubular or tubulous steam boilers.
Great difficulty has hitherto been found in keeping the tubes tight in tube plates
when fixed therein in the usual manner that is by boring holes in the plate and
inserting the tubes therein after which they are expanded The cause of the
difficulty I believe arises in some cases from the distortion of the tube plates and
the consequent distortion in the shape of the holes and this is more particularly
found to be the case when the tube plates are subject to large fluctuations in
temperatures such as for example in boilers for Torpedo boats.
Although the before described method of inserting tubes in tube plates is the
customary system tubes have been frequently screwed into the plates but not in
such a manner as hereinafter described as constituting my Invention the object of
which is to overcome the berein before mentioned defect.
According to my Invention I form both in the holes in the tube plate and on the
tube at the part where it is screwed into the tube plate a screw thread or screw
threads of such a nature that both surfaces of the thread are parallel with one
another such for example as is the case with a square thread by which means it is
evident that although the tube hole may get enlarged or distorted into an oval or
other shape the flat surfaces of the thread of the tube and the thread of the whole
in the tube plate will still remain in close contact thereby preventing the leakage
of the water between the tube and tube plate
Figure 1 of the accompanying Drawing represents a section of a part of a tube
and tube plate attached by screw thread or threads formed according to my
Invention.
Or the thread or threads, in the holes in the tube plate and on the tubes may be
of a dovetail like section as shewn in Figure 2 so that the threads lock together
and when the hole in the tube plate gets enlarged or distorted into an oval or other
shape it forces the tube to become similarly distorted or enlarged whereby the tube
continues to be in close contact with the tube plate throughout its entire circum-
ference at the part of juncture and leakage is therefor prevented.
Having now described and particularly ascertained the nature of my said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and
original and therefore claim as the Invention secured to me by the herein before in
part recited Letters Patent is.
The improvements in tubular and tubulous steam boilers for torpedo boats or
other purpose consisting in effecting the junction of the tubes with the tube plates
by means of a screw thread or screw threads formed substantially as herein before
described and illustrated in the accompanying Drawing for maintaining a tight
junction should the plates or tubes become distorted.
In witness whereof I the said Alfred Fernandez Yarrow have to this my
Specification set my hand and seal this Twenty eighth day of October One
thousand eight hundred and eighty two
ALFRED FERNANDEZ YARROW. (L.S.)