MENTS IN STEAM BOILERS
Year: 1881

page_text: "
PROVISIONAL SPECIFICATION left by the said George Petrie at the Office
of the Commissioners of Patents on the 4th January 1881.
GEORGE PETRIE, of Rochdale, in the County of Lancaster, Engineer.
MENTS IN STEAM BOILERS."
" IMPROVE-
My Invention relates to that class of steam boilers having an internal flue or
flues, and known as Lancashire boilers," and consists in forming a chamber or
chambers within such flues by means of cross. plates placed therein. The plates
forming the ends of such chambers aforesaid I connect by means of tubes through
which the heated products of combustion traversing the flues aforesaid pass.
Through the upper and lower parts of the flue containing the aforesaid tubes I
form openings through which the water contained in the boiler may circulate round
the above named tubes. I also place a cover or guard over the upper opening to
prevent dirt or sediment falling into the chamber.
By the previously described arrangements I obtain increased heating surface or
boiler power, and ensure a better circulation of the water contained in the boiler,
particularly that portion situate below the flues, than ordinarily exists in boilers of
the class above referred to.
In the lower portion of the flue containing the before mentioned tubes I form
an additional opening to that intended for the circulation of the water, such
opening being closed by a cover. The removal of such cover enables the tubes and
chamber containing them to be more readily cleansed.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Petrie in the Great Seal Patent Office on the 4th July 1881..
GEORGE PETRIE, of Rochdale, in the County of Lancaster, Engineer. "IMPROVE-
MENTS IN STEAM BOILERS."
My Invention relates to that class of steam boilers having an internal flue or
Blues, and known as "Lancashire boilers," and consists in forming a chamber within
such flues by means of cross plates placed therein. The plates forming the ends of
such chambers aforesaid I connect by means of tubes through which the heated
products of combustion traversing the flues aforesaid pass. Through the upper and
lower parts of the flue containing the aforesaid tubes I form openings through
which the water contained in the boiler may circulate round the above named
tubes. I also place a cover or guard over the upper openings to prevent dirt or
sediment falling into the chamber..
"By the previously described arrangements I obtain increased heating surface or
boiler power, and ensure a better circulation of the water contained in the boiler,
particularly that portion situate below the flues, than ordinarily exist in boilers of
the class above referred to.
In the lower portion of the flue containing the before mentioned tubes I form
an additional opening to that intended for the circulation of the water, such
opening being closed by a cover. The removal of such cover enables the tubes
and chambers containing them to be more readily cleansed.
In order that my Invention may be fully understood and more readily carried
into practical effect I will now proceed to describe the accompanying Drawing.
Fig. 1 is a vertical longitudinal section, and Fig. 2'a vertical cross section taken
on the line A, B, of Fig. 1, similar letters of reference being used in corresponding
parts in each of the Figures. At a is the outer shell of the boiler, within which
are situate the flues b, b*. As the arrangement I am about to describe is alike in
both flues I will confine my description to one of them only, and to corresponding
parts in the other flue I shall apply the same letters of reference, but with the
addition of an asterisk.
Within the flue b, a portion of which is shewn in section, I fix cross-plates c, d,
so as to form a chamber e within the said flue. Within the chamber e I place a
number of tubes f, one of their ends passing through apertures formed in the cross
plate d, their other ends passing through apertures formed in the other cross plate c.
The ends of the tubes fare made tight in the aperatus in the cross plates c, d, .by
any of the usual methods adapted for such purpose.
The chamber e formed by the cross plates c, d, communicates with the water
contained in the boiler, and surrounding the flues by means of openings g, h,
formed in the upper and under part of the flue b.
.
By placing the cross plates c, d, and tubes f within the flues. of what are known
as Lancashire boilers I am enabled to obtain a great amount of additional.
surface against which the heated products of combustion in their passage along the
flues b, b*, may act, thereby increasing the evaporating or steam producing power
without increasing the length or diameter of the boiler.
The tubes and cross plates c, d, may be of iron, brass, copper, or any other
suitable metal or compound metal.
The opening h formed in the upper part of the flue b, and the opening g formed
in the lower part of the flue b, I place at opposite ends of the chamber e containing
the tubes f. When the water within the chamber e surrounding the tubes f
becomes heated by the products of combustion acting upon the end plates c, d, and
tubes f, the said water will escape by the opening in the upper part of the flue,

page_text: and a fresh supply of water will flow into the chamber e through the lower
opening, as indicated by the arrows. By placing the inlet at the lower side and
near one end of the chamber e, and the outlet at the opposite upper side and near
the other end as shewn, I ensure a thorough circulation of the water surrounding
the tubes f. The water entering the chamber e from the lower portion of the boiler,
and escaping by the upper opening h, produces a complete circulation throughout
the entire mass of water contained in the boiler, thereby tending to produce a
uniformity of temperature of the water situate above and below the flues, and
thus preventing injury to the boiler arising from one portion being at a much
higher temperature than another.
Upon the upper part of the flue b I mount brackets j, k, supporting at their upper
ends a plate or cover l, such cover being for the purpose of preventing dirt or sediment
falling within the chamber e. Below the opening h formed in the upper part of
the flue 6 I form in the lower part of the flue an opening m provided with a plate
or cover n secured to the flue by means of set-screws o, p. During the time the
boiler is in use for generating steam the opening m is kept closed by the plate or
cover n, but when it is desired to clean the chamber e in which the tubes f are
situate the plate or cover n is removed, and the cleaning of the tubes and chamber
is thereby facilitated.
Having thus described and ascertained the nature of my said Invention, and the
manner in which the same is to be performed, I desire it to be understood that I
claim as secured to me under the above in part recited Letters Patent, and for the
purposes above set forth,-
Firstly. Forming within the flue or flues of what are known as Lancashire boilers
a chamber provided with tubes used in combination with openings formed in the
said flue or flues for permitting water to circulate through the said chamber,
substantially in the manner and for the purpose hereinbefore shewn and described.
Secondly. The use of a cover or guard 1 for preventing dirt or sediment falling
into the chamber e, as described and shewn.
Thirdly. The opening m provided with a loose cover n, as and for the purpose
described and shewn.
In witness whereof, I, the said George Petrie, have hereunto set my hand
and seal, this Second day of July, in the year of our Lord One thousand
eight hundred and eighty one.
GEORGE PETRIE. (L.S.)