Improvements in or relating to Steam Generators.
Year: 1889

page_text: Date of Application, 2nd July, 1889:
Complete Specification Left, 1st May, 1890-Accepted, 7th June, 1890.
PROVISIONAL SPECIFICATION.
Improvements in or relating to Steam Generators.
I, GEORGE BROMILOW SHEPHERD, of 6 Crosby Square, London, E.C., Marine
Engineer, do hereby declare the nature of this invention to be as follows:-
The object of this invention is to protect from deposit certain parts of steam
boilers and for generators of steam or evaporators so that the efficiency of the heating
surfaces may be as little impaired as possible. The application of the invention
would necessarily vary according to the construction of the boiler but I will describe
it as applied to a return tube marine boiler internally fired. Around the furnace
tube I prefer to place a shield or shields preferably two of the full length of the
tube or thereabouts and which may be supported upon the shell of the boiler or in
any other convenient manner. This shield is open upon the top or if two shields
are employed they do not meet so as to leave an open space over the top of the
furnace and above this opening 1 place a soparate guard or it may be a portion of
the shield or shields already described. Suitable means are provided for allowing
the water or other fluid to reach the outside of the furnace; this may be done by
cutting away a portion of the lower part of the shield for approximately its whole
length or there may be a number of openings and any or all of these may be provided
with tubes or funnels deflectors or the like for the purpose of directing the flow of
the liquid during circulation.
-
This or an equivalent arrangement of shields would be provided in connection
with each of the furnace tubes.
The action is as follows :-
The water or liquid being heated by the furnace and particularly by the upper
portion of the furnace tube rises rapidly in the space between the outside of the tube
and the inside of the shield escaping at the top through the opening already described
the final direction of the current as it leaves this opening being modified or directed
by the guard plate tubes or nozzles as may be desired.
The primary object of the guard plate over the opening at the top of the shield is
to prevent scale or sediment falling from above settling upon the crown of the
furnace tube as it might do were the opening in the shield unprotected.
As with an internally fired boiler of this description the collection of scale or
deposit upon the lower portion of the shield is not of much importance it. would.
generally not be necessary to provide any, particular means for causing the special
circulation of the liquid against the shield but where the boiler is externally fired or
the products of combustion from the furnace are carried back from outside the shield
means may be employed for causing a specially strong circulation of the water against
the interior of the shield.
One means of doing this would be to provide in connection with the above
described shield or shields any suitable form of tubes deflectors or equivalent which:
would leave a sufficiently narrow passage between it or them and the shield at the.
required parts so that a strong scouring action of the liquid from the interior of the:
shield would be maintained while the boiler was in use.
It will be well understood that considerable modifications in the means employed
in carrying out this invention may be made and in many cases would necessarily
have-to be made without departing from the spirit of the invention.
Dated the 2nd day of July 1889.

page_text: COMPLETE SPECIFICATION.
Improvements in or relating to Steam Generators.
I, GEORGE BROMILOW SHEPHERD, of 6 Crosby Square, London, E.C., Marine
Engineer, 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 :-
The object of this invention is to protect from deposit certain parts of steam
boilers and the generators of steam or evaporators so that the efficiency of the
heating surfaces may be as little impaired as possible, and at the same time to create
a better circulation of the water from the bottom of the boiler where it usually lies
somewhat dead and cold. The application of the invention would necessarily vary
according to the construction of the boiler but I will describe it as applied to a
return tube marine boiler internally fired. Around the furnace tube I prefer to
place a shield or shields preferably two of the full length of the tube or thereabouts
and which may be supported upon the shell of the boiler or in any other convenient
manner. This shield is open upon the top or if two shields are employed they do not
meet so as to leave an open space over the top of the furnace and above this opening
I place a separate guard or it may be a portion of the shield or shields already
described. Suitable means are provided for allowing the water or other fluid to reach
the outside of the furnace; this may be done by cutting away a portion of the lower
part of the shield for approximately its whole length or there may be a number of
openings and any or all of these may be provided with tubes or funnels deflectors or
the like for the purpose of directing the flow of the liquid during circulation.
This or an equivalent arrangement of shields would be provided in connection with
each of the furnace tubes
The action is as follows:-
The water or liquid being heated by the furnace and particularly by the upper
portion of the furnace tube rises rapidly in the space between the outside of the
tube and the inside of the shield escaping at the top through the opening already
described the final direction of the current as it leaves this opening being modified
or directed by the guard plate tubes or nozzles as may be desired.
The primary object of the guard plate over the opening at the top of the shield is
to prevent scale or sediment falling from above settling upon the crown of the furnace
tube as it might do were the opening in the shield unprotected.
As with an internally fired boiler of this description the collection of scale or
deposit upon the lower portion of the shell is not of much importance it would
generally not be necessary to provide any particular means for causing the special
circulation of the liquid against the shell but where the boiler is externally fired or
the products of combustion from the furnace are carried back from outside the shell
means may be employed for causing a specially strong circulation of the water against
the interior of the shell.
One means of doing this would be to provide in connection with the above described
shield or shields any suitable form of tubes deflectors or equivalent which would
leave a sufficiently narrow passage between it or them and the shell at the required
parts so that a strong scouring action of the liquid from the interior of the shell
would be maintained while the boiler was in use.
In the accompanying drawings
Fig. 1 is a transverse section showing my invention applied to a marine boiler
having three furnaces this section being taken on the line a-b of Fig. 2 which is
itself a longitudinal section taken on the line c-d of Fig. 1. Fig. 3 is a transverse
section showing my invention applied to a marine boiler having two furnaces.
Like letters indicate like parts throughout the drawings.
In Figs. 1 and 2 A is the shell of the boiler A¹ Å² the furnace tubes A³ the
return flue tubes and A1 and A' the front and back plates in which the ends of the
flue tubes A³ are secured; all these parts are of ordinary construction.

page_text: B is the shield which as applied to the tube A* may consist of two parts BB
each composed of one plate or as shown in the drawing of two or more plates jointed
together and between the upper eiges of which parts is left a space B. These two.
parts B and B³ extend down to the shell A where they are partly cut away and where
by the parts not ent away they are secured to said shell by angle iron or equivalent
brackets B². These downwardly extending parts B³ cause the water to circulate
through the openings B provided by the parts cut away and close around the tube A
as indicated by the arrows in Fig. 1.
If desired the before described shield may be formed of one plate only this being
bent so as to fit over the tube A2 and having an opening at its upper part in
substantially the same manner as the shield shown in Fig. 1..
Above the space B' is provided a plate C preferably doubly inclined as shown this
being supported in any convenient manner but preferably at its ends. by means of
brackets (secured to the tube plates A' and A. and in such a position that it will
leave openings C for the circulation of the water as indicated by the arrows.
As applied to the flue tubes A' each of the shields B may consist of two parts
each composed of two plates b which may be closely jointed together as are the
plates of the shields around the tube A or the said plates may be supported on the
brackets so as to leave spaces 6 between their adjacent edges as shown in Fig. 1, so
as to allow the water to flow freely between them while at the same time causing it
to circulate strongly against the upper or hottest part of the furnace tube A' as
shown by the arrows.
In Fig. 3 the apparatus is substantially the same as that applied to the tubes A¹
in Fig. I the only practical difference being that the two furnace-tube-shields meet
between the furnace-tubes so as to ensure that all the water between them shall
circulate strongly against their hottest parts whence it escapes through the
openings band C as indicated by the arrows.
Instead of the openings 6' B and C which extend practically the whole distance
between the tube plates A* A' there may be a number of smaller openings which may
if desired have tubes funnels or deflectors secured to the whole or only a part of
them for the purpose of directing the flow of the water during circulation.
The action of the before described apparatus is as follows:-
The water or liquid being heated by the furnace, particularly by the upper portion
of the furnace tube rises rapidly in the space between the outside of the tube A¹
or A³ and the inside of the shield B escaping at the top through the openings 6¹
and Cor in the case of the tube A³ through the openings C only, the final
direction of the current being modified or directed by the plate C or by the before
referred to tubes or deflectors provided instead of or in addition to the openings 6'
and C.
The primary object of the plate Cover the opening B' is to prevent scale or
sediment from outside the shield falling from above or settling upon the crown of
the furnace tubes A¹ or A' as it might do were the opening B' unprotected and which
by covering up the hottest part of each such tube would have the effect of seriously
impairing the efficiency of the boiler.
It will be well understood that modifications in the means employed in carrying.
out this invention may be made and in many cases would necessarily have to be
made without departing from the spirit of the invention.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I am aware that it is not new
to apply to a boiler furnace tube a shield for causing the liquid to circulate between
such shield and the furnace tube and do not therefore broadly claim such a device
per se but what I do claim is :-
1. In a steam generator the combination with a shield such as B partly surround-
ing the furnace tube and having an opening such as B' at its upper part of a plate
or guard such as C for preventing the scale or sediment settling on the crown of the

page_text: furnace tube substantially as described and illustrated in the accompanying
drawings.
2. In a steam generator a shield such as B composed of two parts one on each
side of the centrali line of the furnace tube and having a space B¹ between them
over the crown of said furnace tube each of the two parts being composed of two or
more plates.b between which are spaces 6 for the circulation of liquid substantially
as herein described and illustrated in the accompanying drawings.
3. In a steam generator the combination with a furnace tube of a shield such as B
open at B¹ and protected by a cover such as C and baving its two parallel sides B³
extended to the boiler shell where they are cut away at B₁ to allow of the passage of
water substantially as described and illustrated in the accompanying drawings.
4. The complete furnace tube shield. substantially as described and illustrated in
the accompanying drawings.
Dated thisIst day or mayV..
G. B. SHEPHERD.
W. P. Thompson & Boult,
Agents for the Applicant..