Improvements in and relating to the Supply and Distribution of Forced Draught in Stationary Land Steam Boiler Furnaces.
Year: 1897

page_text: Date of Application, 25th Sept., 1897
Complete Specification Left, 25th June, 1898-Accepted, 17th Sept., 1898
PROVISIONAL SPECIFICATION.
Improvements in and relating to the Supply and Distribution of
Forced Draught in Stationary Land Steam Boiler Furnaces.
I, SYDNEY LAVER GREGOR, of 21, Cwmdonkin Terrace, Swansea, Mining
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention has reference to supply and distribution of forced draught in
the furnaces of stationary land steam boilers. It is specially applicable to
boilers of Lancashire and like types, such as are ordinarily employed for supply-
ing steam for driving machinery in works of various kinds.
According to this invention hollow fire-bars are employed. The bars are open
at the front end and closed at the inner or rear end. At the front end the bars
fit into the back of a chamber which extends along the furnace transversely to
the fire bars. The fit between the bars and the back of the said chamber is
airtight and at the end of the chamber each bar lies closely to that next it
and thus air is prevented from passing otherwise than through the bars. The
top of the chamber forms the dead-plate of the furnace and is fitted at front
with a removable box or hood having an inner face in which are apertures
situated at intervals. Communicating with the cover or hood is a pipe open
at one end. Into the open end of this pipe is projected the nozzle of a steam
pipe between which nozzle and the mouth of the pipe into which it is projected
is a space of an extent depending on the difference in diameter of the two pipes.
As is well understood, injection of a jet of steam through the nozzle induces
a current of air or blast in the pipe into which the nozzle is projected. A cock
or valve regulates the jet of steam. The blast induced enters the box or hood
aforesaid and passes thence into the chamber, to which it is fitted, through the
apertures provided as aforesaid in the back wall of the cover or hood. From
the chamber the blast is delivered into the fire-bars and thence issues into the
furnace through apertures provided in the tops and sides of the bars.
Under this invention economy in steam for inducing a forced draught is
effected and the draught so induced is more uniformly distributed throughout
the furnace.
Dated this 24th day of September 1897.
Improvements in and relating to the Supply and Distribution of
Forced Draught in Stationary Land Steam Boiler Furnaces.
I, SYDNEY LAVER GREGOR, of 21, Cwmdonkin Terrace, Swansea, Mining
Engineer, do hereby declare the nature of this invention, and in what manner
[Price 8d.]

page_text: the same is to be performed, to be particularly described and ascertained in and
by the following statement; -
This invention has reference to supply and distribution of forced draught in
the furnaces of steam boilers. In the Provisional Specification left with my
application for a patent to this invention, and in the title adopted therefor, it
is indicated that the invention relates to land boilers. Since the said applica-
tion was made, the invention has proved equally applicable to marine boilers,
and as no alteration in the principles of the invention or in general construction
is entailed in the application to marine boilers, they are comprised as well as
land boilers among those to which this invention relates.
According to this invention, hollow fire-bars are employed for the furnace.
The bars are open at their front ends and closed at the rear ends. At the front
ends the bars 'fit into the back of an air-distributing chamber which extends
transversely along the furnace front.
The bars fit the said chamber closely and also lie closely together at the
front ends so that air from the chamber cannot enter the furnace except through
the bars, which latter are slotted at intervals on the top and have also apertures
in the sides. The distributing chamber, the top of which forms the deadplate
of the furnace, is covered on the outside by a hood secured in place by bolts
passed through it and into vertical bars provided at the front of the chamber.
The hood is open throughout on the inner face, or it may have an inner wall
having apertures therein made at suitable distances apart. The hood, which is
closed at one end, communicates with a pipe connected to its other end, or the
hood may be extended to form such pipe. Into the outer end of the pipe, which
may be bell-mouthed, is projected the nozzle of a steam injector, between which
nozzle and the inside of the pipe is a space. By injecting a jet of steam from
the injector into the pipe a forced draught is, as is well understood, created,
and the air blast thus created is conducted into the hood aforesaid, thence into
the distributing chamber and delivered to the furnace through the fire-bars.
In a furnace having fire-bars of the kind above described and having applied
thereto the draught-creating and distributing apparatus also above described,
there is an uniform supply and pressure of air blast under every part of the
fire, and the result obtained is more uniform and complete combustion and a
fire of great heat burning with greater uniformity over the whole area of the
furnace.
Referring to the accompanying drawings, Fig. 1 represents in front end view,
partly sectional, a steam boiler having two furnaces both of which are separately
fitted with my improvements in and relating to the supply and distribution of
forced draught in the furnaces thereof. The arrangement, though distinct in
each furnace, is the same in each, and, therefore, to simplify the description, the
singular number is adopted. The boiler illustrated in the accompanying draw-
ings is an ordinary Lancashire boiler. Fig. 2 is a longitudinal vertical section
on the line o, o, Fig. 1. Fig. 3 is a sectional plan on the line p, p, Fig. 2.
Fig. 4 is a sectional plan on the line q,q, Fig. 1. The sectional part of
Fig. 1 is taken on the line r, r, Fig. 2.
The fire-bars a are hollow throughout, as shown. They are open at the front
ends and closed at the rear ends. They have apertures a¹ at intervals along
the top, and holes a² at intervals along the sides, as shown. At the rear the
bars rest on a cast iron bridge in which is a plug door. Figs. 5, 6, 7
and 8 represent, at an enlarged scale, various views of bars. Fig. 5
is a front end view of two bars. Fig. 6 is a side view of the
two ends of a bar, having the intervening part removed. Fig. 7 is a
rear end view of a bar showing the end plug by which that end is closed.
Fig. 8 is a transverse section of a bar on the line s, s, Fig. 6. At the front
ends the fire-bars a open into a chamber b which extends transversely across
the flue. The top of the chamber b forms the deadplate of the furnace.
The

page_text: front ends of the bars a so fit in place in the rear wall of the distributing
chamber that passage of air from the chamber to the furnace except through
the bars is prevented. The chamber b is closed on the outside by a hood or
cover c which is secured in place by bolts d tapped into bars e extending verti-
cally in the chamber. The hood c may, however, be secured in place in other
ways, as, for example, it may be bolted to flanges provided on the chamber b.
At one end the hood c is closed. The closed end is at one side of the flue.
Towards the other end the hood is connected to a pipe f into the open end of
which is projected the nozzle of an injector y (Fig. 1) supplied with steam from
the pipe g¹. A curtain or cover ½ of cast iron closes the mouth of the ash-pit
or under part of the boiler flue, and in this curtain is provided a door i for
removal of ashes.
From the injector g a jet of steam, the size of which is regulated by the usual
plug, is injected into the pipe f. The forced blast thus obtained is conducted
by the pipe f to the hood c. Thence it is delivered into the chamber b whence
As
it is distributed into the tubular fire-bars a and delivered therefrom into the
fire through the apertures a¹ in the tops and a² in the sides of the bars.
aforesaid, the forced draught enters the fire only by way of the apertures in the
fire-bars and, accordingly, an uniform supply and pressure of air are obtained
over the full area of the fire, resulting in more uniform and more perfect
combustion.
'
Instead of being open-sided at the inside the hood c may have a grated wall,
as seen at Fig. 9, the wall having apertures therein such as c¹ situated at suitable
distances apart, thus making the wall grated.
The application of this invention to the furnaces of marine and other boilers
of different types to that shown in the appended drawings entails no departure
from the principles of the invention nor in general construction of the parts.
It is performed in practically the same way as hereinabove described with refer-
ence to the said drawings.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is;
The method of and means for supplying and distributing forced draught in
steam boiler furnaces substantially as herein before described with reference to
the accompanying drawings, that is to say, by conducting the forced draught
derived from injecting steam from an injector into a pipe, or from other blast
producing appliance, into a chamber such as extended along the face of the
furnace and closed on the outside by a hood or cover such as c, or the like; from
which said distributing chamber the blast is distributed into hollow tubular
fire-bars such as a opening at their front, ends into the said distributing chamber b,
closed at their rear ends, and having apertures in their tops and sides whereby
the forced draught is delivered into the fire..
Dated this 24th day of June 1898.
NICHOLAS WATTS,
Chartered Patent Agent, Bristol.