Improvements in or relating to Steam Generators.
Year: 1889

page_text: Date of Application, 4th Nov., 1889
Complete Specification Left, 31st July, 1890-Accepted, 4th Oct., 1890
PROVISIONAL SPECIFICATION.
Improvements in or relating to Steam Generators.
We, WILLIAM WEDGEWOOD BASTOW, of Scarborough Street, West Hartlepool, in
the County of Durham, Commission Agent, and CHARLES BASTOW CASEBOURNE, of
Greatham, also in the County of Durham, Marine Engineer, do hereby declare the
nature of this invention to be as follows:-
.
Our invention relates to steam generators and is especially applicable to the type of
steam generators known as marine boilers in which the requisite capacity for steam and
water space can only be obtained by constructing such boilers with a large diameter,
in consequence of which only a moderate pressure of steam can be safely generated
if the boiler shell is to be constructed of plates of a thickness within the limits of
practical utility.
The object of our invention is to construct boilers of this class in a particular
manner so that steam of high pressures may be generated in them within a shell con-
structed of plates of moderate thickness.
In describing how our invention may be carried into effect we will refer more
particularly to cylindrical boilers which we construct with a double shell forming an
annular space all round the barrel of the boiler and if desired with a cylindrical space
at each end of the boiler. The object of providing a double shell is to charge the
space between the two shells with steam of a lower pressure than that generated
within the inner shells which is thus relieved of the full pressure of steam in the
boiler and is only subjected to the excess of the pressure of the steam within over
the pressure of the steam enclosed between the two shells as for example a boiler
constructed to stand a pressure of 150 lbs. to the square inch can be employed as the
inner shell of a boiler constructed according to our invention in which steam is
generated to a pressure of 250 lbs. per square inch, the extra 100 lbs. presssure being
neutralized or balanced by an external pressure of the same amount exerted by the
steam enclosed between the two shells. As the object of providing a space between
the two shells is to provide a means of applying à neutralizing or balancing external
pressure to the inner shell of the boiler, it is of course immaterial what fluid or gaseous
body is charged into this space so long as the requisite external pressure is regularly
and constantly operating, but as the steam generated within the boiler is the most
available source of supply for charging the space between the two shells with a
suitable gaseous body, we prefer to use it, and in order to provide for its admission to
the space between the shells automatically and to the requisite or intended pressure
we provide one or more regulating valves between the two shells constructed on the
principle of an ordinary spring loaded safety valve mounted upon a valve scat provided
in the inner shell in such a manner that when the steam between the two shells is
below a certain pressure the steam within the boiler forces the valve open and fills
the space until the required pressure is reached when the valve closes; one or more
similar valves mounted on the inside of the inner shell in an inverted position may be
employed if required to prevent the posibility of the external pressure on the inner
shell ever exceeding the internal pressure should the internal pressure from accident
or any cause whatever be suddenly reduced. It is of course obvious that our invention
as herein described with reference to cylindrical boilers is equally applicable to boilers
of other form and construction in which the internal pressure is exerted upon large
areas.

page_text: COMPLETE SPECIFICATION.
Improvements in or relating to Steam Generators.
WILLIAM WEDGEWOOD BASTOW Commission Agent 112 Scarbro' Street West
Hartlepool CHARLES BASTOW CASEBOURNE Consulting Engineer Victoria Terrace,
West Hartlepool, 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 :-
Our invention relates to steam generators and is especially applicable to the type of
steam generators known as marine boilers in which the requisite capacity for steam
and water space can only be obtained by constructing such boilers with a large
diameter in consequence of which only a moderate pressure of steam can be safely
generated if the boiler shell is to be constructed of plates of a thickness within the
limits of practical utility.
1
The object of our invention is to construct boilers of this class in a particular
manner so that steam of high pressure may be generated in them, within a shell
constructed of plates of a moderate thickness.
In describing how our invention may be callied into effect we will refer more
particularly to cylindrical boilers which we construct with a double shell forming an
annular space all round the barrel of the boiler and if desired with a cylindrical
space at each end of the boiler. The object of providing a double shell is to charge
the space between the two shells with steam of a lower temperature than that
generated within the inner shell which is thus relieved of the full pressure of steam
in the boiler and is only subjected to the excess of the pressure of the steam within
over the pressure of the steam enclosed between the two shells; as for example:-a
boiler constructed to stand a pressure of 150 pounds to the square inch can be
employed as the inner shell of a boiler constructed according to our invention in
which steam is generated to a pressure of 250 pounds to the square inch the extra
100 pounds being neutralised or balanced by an external pressure of the same amount
exerted by the steam enclosed between the two shells. As the object of providing a
space between the two shells is to provide a means of applying a neutralising or
balancing external pressure to the inner shell of the boiler, it is of course immaterial
what fluid or gaseous body is charged into this space so long as the requisite external
pressure is regularly & constantly operating, but as the steam generated within the
boiler is the most available source of supply for charging the space between the two
shells with a suitable gaseous body, we prefer to use it, and in order to provide for
its admission to the space between the two shells automatically and to the requisite
and intended pressure we provide one or more adjusting valves between the two
shells constructed on the principle of an ordinary spring loaded safety valve, mounted
upon a valve seat provided in the inner shell in such a manner that when the steam
between the two shells is below a certain pressure, the steam within the boiler forces
the valve open & fills the space until the required pressure is reached when the valve
closes:
One or more similar valves mounted on the inside of the inner shell in an inverted
position may be employed if required to prevent the possibility of the external
pressure on the inner shell ever exceeding the internal pressure should the internal
pressure from accident or any cause whatever be suddenly reduced. It is of course
obvious that our invention as herein described with reference to cylindrical boilers is
equally applicable to boilers of other form and construction in which the internal
pressure is exerted upon large areas.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed we declare that what we
claim is :-
1. A very high pressure obtainable with the use of comparatively thin, and there-
fara mara moliable alates in the chall

page_text: 2. A great economy of fuel consequent upon the higher pressure obtainable.
3. The circulation at bottom of boiler is much improved, the temperature at this
portion of the boiler being the same as at any other portion.
4. Greater heat retaining power, the outer shell forming a jacket containing
steam which acts in the same manner as do the jackets on engine cylinders.
5. Increased facility of construction, the lighter and thinner plates being easier to
handle & work.
6. The plates being made thinner contain less carbon & are therefore more reliable
and more uniform in their strength.
Dated this 30th day of July 1890.
WILLIAM WEDGEWOOD BASTOW:
CHARLES BASTOW CASEBOURNE.