Year: 1899

page_text: Date of Application, 25th Mar., 1899
t
I, JOHN COWAN, Managing Director of The Stirling Boiler Company, Limited,
2, St. Andrew Square, Edinburgh, do hereby declare the nature of this invention
to be as follows:
My invention relates to improvements in water tube boilers in which the main
part of the heating surface consists of tubes joining upper steam and water drums
with lower water drums, and has for its object to increase the heating surface
without greatly increasing the dimensions of the boiler.
One part of my invention consists in an improved form and construction of
boiler having essentially at its upper part three steam drums and a feed water
drum all containing steam and water; each of the former being connected from
below the water level by a bank of tubes to one common bottom drum, and being
also connected each to each by tubes both above and below the water level. Fur-
ther the feed water drum is connected to the steam drums by tubes above the
water level water only and to a lower mud drum by tubes from below the water
level; this lower mud drum is preferably placed slightly below the level of the
main water drum with which it is connected by tubes at its upper part.
at
Another part of my invention has for its object to prevent excessive differ-
ences of temperature between the various parts of the boiler on starting to raise
steam, and consists in providing a bye pass flue from the furnace to that portion
of the combustion chamber or Hue which contains the bank of tubes connecting
the mud drum with the water feed drum. I prefer that this flue should pass up
an angle from the furnace to near the top of the bank of tubes entering the water
feed drum. By means of the bye pass this bank of tubes is raised in temperature
in starting more equally with the rest of the boiler. When the boiler has been
thus started and the temperature sufficiently raised I close the flue by suitable
means. In a further part of my invention I provide an outside tube connecting
the water space of the water feed drum with the main water drum and on this
pipe I place a suitable valve so that when steam has been raised and normal
circulation established this valve can be closed. The object of this tube is to
increase the water circulation during the period of raising steam.
In carrying my invention into effect according to one modification, I provide
three steam drums each containing water and steam, the steam spaces of which
are connected together by means of tubes, and they are also connected together
below the water level by tubes. Below these three steam and water drums I
place a main water drum, connected by banks of tubes with each of the three
steam drums. These connecting tubes enter the drums below the water level.
The main water drum I connect by pipes with a mud drum running parallel to
the water drum, and preferably arranged on a lower level than the latter, the
tubes from which preferably enter the mud drum from near its top. On about
the level of the steam and water drums I provide a water feed drum connected

page_text: at its upper part with the steam space on the steam drum by tubes. The bottom
of this drum is connected by a bank of tubes to the mud drum.
The tubes joining the water drum with the upper steam drums pass into the
upper drums below the water level in each case. The main water circulation due
to generation of steam takes place between these three drums and the bottom
drum by way of the water tubes. Some of each set probably act as down comers
for water, and others as up-takes for water and steam. Suitably placed fire-
resisting baffle plates are provided to deflect the furnace gases so as to cause
them to come in contact to the greatest possible extent with the water tubes.
The water tubes joining the water feed drum and the mud drum being the
last of the series, and next to the furnace gases from the boiler flues, will be least
heated, so that comparatively quiet circulation is caused between these drums
through the connecting tubes by the heat from the gases. This bank of tubes
therefore acts more like a water heater there being comparatively little evapora-
tion taking place from them. The furnace is usually placed below the end steam
drum, and the front of the furnace is practically below the side of that end drum.
Therefore the gases pass through the banks of tubes in series, across the length
of the steam drums. Suitable fire-resisting baffle plates are also provided between
the steam drums above the level of the water pipes connecting the drums, and
below the level of the pipes connecting the steam spaces of these drums.
This arrangement of a separate mud drum in which the circulation is not
violent provides for the accumulation of the main part of the deposit from the
water in this drum, and special provision is made for readily cleaning this drum.
man-holes being provided at each end. The mud drum is only connected to the
water feed drum, and to the main water drum. No pipes pass from it to any
of the steam drums forming the boiler proper. The feed drum also is not con-
nected with the steam drums below their water level, but has its only connection
from steam space to steam space. The water feed pipe is arranged in the water
feed drum to deliver the feed water into a trough arranged at a fixed height in
the drum. The water takes the level in the water feed drum therefore by over-
flowing from the trough. This trough arrangement prevents what is known as
water hammer in the range of supply pipes, and provides for the supply of feed
water being always into the water in the trough the level of which is indepen-
<lent of the water level in the feed drum proper.
In carrying the further parts of my invention into effect according to one
modification I provide at either or both sides of the boiler a bye-pass flue, which
passes preferably upwards at an angle, and joins the main combustion chamber
or flue at a point near the top of the bank of tubes passing from the water feed
drum to the mud drum. This flue shunts part of the furnace gases at the high
temperature, and causes them to mix with the gases which are passed through the
first three banks of tubes, thus causing the parts of the boiler to be more equably
raised in temperature when steam is being raised in the first instance. When
the full pressure has been obtained, and the water is therefore properly heated,
this bye-pass flue may be shut.
I further provide an outside pipe preferably at the ends of the drums, joining
the main water drum to the water feed drum. This pipe I provide with a suit-
able valve, so that when steam has been raised, the valve may be shut. This
valve will be opened before starting the boiler, and increased circulation will be
caused during the raising of steam, to further assist in equably raising the tem-
perature of the whole of the parts of the. boiler.
MARKS & CLERK,
18, Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and
25, Cross Street, Manchester, Agents.

page_text: improvements in Water Tube Boilers.
I, JOIN COWAN, Managing Director of The Stirling Boiler Company, Limited,
of 2, St. Andrews Square, Edinburgh, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement: —
My invention relates to improvements in water tube boilers in which the main
part of the heating surface consists of tubes joining upper steam and water drums
with lower water drums, and has for its object to increase the heating surface
without greatly increasing the dimensions of the boiler.
One part of my invention consists in an improved form and construction of
boiler having essentially at its upper part three steam drums and a feed water
drum all containing steam and water: each of the former being connected by a
bank of tubes to one common bottom drum called the main water drum, and
being also connected each to each by tubes both above and below the water
lever. Further the feed water drum is connected to steam drums by tubes above
the water level only and to a lower mud drum by tubes from below the water
level: this lower mud drum is preferably placed slightly below the level of the
main water drum with which it is connected by tubes at its upper part.
Another part of my invention has for its object to prevent excessive differ-
ences of temperature between the various parts of the boiler on starting to raise
steam, and consists in providing a bye pass flue from the furnace to that portion
of the combustion chamber or flue which contains the bank of tubes connecting
the mud drum with the water feed drum. I prefer that this flue should pass up at
an angle from the furnace to near the top of the bank of tubes entering the water
feed drum. By means of the bye pass this bank of tubes is raised in temperature
in starting more equally with the rest of the boiler. When the boiler has been
thus started and the temperature sufficiently raised I close the flue by suitable.
means.
In a further part of my invention I provide an outside tube connecting the
water space of the water feed drum with the main water drum and on this pipe I
place a suitable valve so that when steam has been raised and normal circula-
tion established this valve can be closed. The object of this tube is to increase
the water circulation during the period of raising steam.
-:
Referring now to the accompanying drawings which illustrate my invention:-
Figure I is a sectional elevation of a boiler constructed according to my
invention.
Figure 2 is a plan of the same.
of Figure 3.
by the bank of tubes a,
water drum C by the
joined to the drum C'
Figure 3 is an elevation of the feed water drum of the boiler and,
Figure 4 is a cross section of the same on the line
A is a feed water drum connected to the mud drum C
B, B and B are the steam drums connected to the main
banks of tubes 6, 61, and 6 respectively. The drum C is
by pipes which enter the drum C³ at its upper part.
The steam drum B is joined to the steam drum B₁ by tubes N above and
tubes N¹ below the water level, and to the steam drum B2 by tubes P above the
water line and tubes P¹ below water. The steam drum B is connected to the
feed water drum A only by tubes M above the water line.. The tubes a must
enter the drum A below water but the tubes 6, 61 and 62, may enter the steam
drums B, B and B either above or below the water level, provided that some
always enter below water. The main water circulation due to generation of

page_text: steam takes place between the three steam drums B, B1 and B2 and the main
water drum by way of the water tubes 6; 61 and 62. Some of these tubes act
as down-comers for water and others as up-takes for water and steam.
The furnace E is placed below and beyond the bank of tubes b' and the furnace
gases are deflected by baffle plates H, J, and K so as to pass up along and
between the tubes 61 then down among the tubes 6 up again among the tubes be
and lastly down between the tubes a to the chimney fiue L. Suitable fire-resist-
ing baffle plates R and S are also provided between the steam drums, above the
water pipes connecting these drums and below the pipes connecting the steam
spaces of the drums.
This arrangement of a separate mud drum in which the circulation is not
violent provides for the accumulation of the main part of the deposit from the
feed water in this drum, and special provision is made for readily cleaning this
drum, a blow off pipe and manhole door being fitted for this purpose. The mud
drum is connected only to the water feed drum and to the main water drum. No
pipes pass from it to any of the steam drums forming the boiler proper. Also
the feed drum is not connected with the steam drums below their water level
but has its only connection from steam space to steam space.
The water feed pipe F Figures 1, 3 and 4 is arranged to deliver water into a
trough G in the feed water drum A and to let it How in below the water level
in the trough. The trough is situated above the water level in the drum and the
water flows over the side of the trough into the drum. By this means the feed
water pipe always discharges below water and what is known as water hammer
in the range of supply pipes is prevented. This trough also distributes the feed
water equally throughout the length of the drum thus preventing the feed water
passing down one or two tubes only.
I may provide at either or both sides of the boiler a bye-pass flue T shown in
the dotted lines in Figure 1.
This bye-pass flue leads direct from the furnace to the bank of tubes a and
is provided with a damper so that it may be closed or open as desired. This flue
which shunts part of the furnace gases at a high temperature past the banks of
tubes 61,6 and 63 may be used to heat the feed water in the bank of tubes a and
to prevent excessive differences of temperature between the various parts of the
boiler on starting to raise steam.
I may also provide an outside pipe U preferably at the ends of the drums, join-
ing the main water drum C to the feed water drum A. This pipe I provide with
a suitable valve V, so that, when steam has been raised, the valve may be shut.
This pipe is used when the boiler is being started and its purpose is to encourage
circulation such as will ensure nearly equal rise of temperature in the various
parts of the boiler.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
1. A water tube boiler consisting of an upper feed water drum such as A and
three steam drums such as B, B1 and B connected together by tubes such as M,
N, N, P and P¹ and to two lower drums such as C and C¹ by banks of tubes such
as a, b, b¹ and 6, the said lower drums being connected to each other by tubes Q
substantially as described with reference to the accompanying drawings.
2. The improved water tube boiler hereinbefore described with reference to
the accompanying drawings.
3. The combination with the water tube boiler as claimed in Claim 1 of an
outside tube connecting the feed water drum with the main water drum, the said
tube being fitted with a suitable valve, substantially as described.
4. The combination with the water tube boiler as claimed in Claim 1 of a bye-
pass flue from the furnace to the most remote bank of tubes with means for
closing the flue when desired, substantially as described.

page_text: 5. In the water tube boiler as claimed in Claim 1 the arrangement of the bank
of tubes a acting as a feed water heater, substantially as described with reference
to the accompanying drawings.
6. The arrangement of a feed trough containing a feed pipe so that the latter
is always below water level thus preventing water hammer in the feed pipes
and so that the feed water is distributed equally throughout the length of the
drum, substantially as described.
ember 1899.
MARKS & CLERK,
18, Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and
25, Cross Street, Manchester, Agents.
ed this 22nd day of December 1899.
MARKS & CLERK,
18, Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and
25, Cross Street, Manchester, Agents.