IMPROVEMENTS IN. AND .CONNECTED WITH BOILER FURNACES
Year: 1884

page_text: COMPLETE SPECIFICATION,
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We CHARLES ALBERT KNIGHT and GEORGE WILLIAM THODE, both of the
Babcock and Wilcox Company; Glasgow; in the County of Lanark; Engineers; do
hereby declare the nature of our said Invention for "IMPROVEMENTS IN. AND
.CONNECTED WITH BOILER FURNACES," and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:
"t
When gaseous or bituminous coals are employed as fuel in boiler furnaces, the
gases or volatile products which they yield are rapidly generated at a low tem-
perature and large volumes of unconsumed gases pass off by the flues to the
chimney, such gases having been chilled, or cooled, down to a temperature below
that at which ignition takes place by contact with the, comparatively cold surfaces
of the boiler tubes. So much so is this the case that the combustion which should
take place within the furnace chamber often takes place when the gases reach the
external air at the top of the chimney. This is more especially, the case in boilers
of the tubular and water-tube classes, and particularly when they are forced;
the efficiency of the boiler and economy of the fuel being in consequence very
greatly reduced.
According to our Invention as applied to boilers, with horizontal or inclined
water-tubes, we fill up the spaces between the tubes in the front section in such a
manner as to form over the furnace a series of heat retaining flues or regenerators,
which by maintaining a comparatively uniform heat above the ignition point, ensure
the perfect combustion of the gases evolved by the fuel, as they pass through the
said flues, and before they are brought into effective use. Contrary to the usual
setting of these boilers we further provide flues or passages b either at one or both
sides of the series of tubes, and extending the length of the front section of the
tubes. This affords free passage to a large body of flame practically without
coming in contact with the surfaces of the boiler, until the chamber b¹ over the
tubes is reached, where the lesser currents of gases passing through the flues a
between the tubes, impinge against the flame and upper part of the boiler, and
complete union and combustion of the gases take place.
It will be seen that the object is to retard the contact of the gases with the
surfaces of the boiler until they shall have perfected their combustion; thus giving
an efficiency and economy not otherwise obtained, which we find to be the case
with our Invention.
In the accompanying Drawings which illustrate one mode of carrying out our
Invention, Figure 1 is a longitudinal section, and Figure 2 a transverse vertical
section of part of a boiler of the kind known as the Babcock and Wilcox water-
tube boiler, showing our improvements applied. Figure 3 is an enlarged view of
two of the water tubes illustrating the mode in which we prefer to fill up the
spaces between the tubes by suitably shaped bricks or blocks C, of fire-clay or other

page_text: refractory material; and Figure 4 is an elevation of one of the bricks or blocks
which are fitted between the tubes.
Referring to these Drawings it will be observed that in the front section of the
tubes A immediately over the fire-grate B of the boiler, the spaces between the.
tubes are filled up with bricks or blocks C of a material such as fire-clay, which
besides being of a refractory character possess the property of absorbing and
retaining heat in a high degree. The bricks or blocks are preferably made hollow,
and are of oblong shape, their longitudinal edges being curved to fit the tubes
between which they rest, and they are retained without setting or cement, the
blocks being of such section and so placed in inclined rows that they are retained
in position by their own gravity. The blocks are fitted in a number of lengths to
fill up the spaces between the inclined rows of tubes in nearly the entire length of
the first section.
.
In the sides or back or in the front wall or in other parts of the furnace, small
holes or openings D are formed to admit air to mix with the gases which rise from
the fuel consumed on the fire-grate B. The rising gases pass up through the flue-
like spaces a left between the rows of tubes A in the first section, and pass round
the baffle plate or division E and down through the succeeding section in the usual
way, and in their passage through the flues a combustion takes place, and the
temperature of the bricks or blocks between the tubes is raised to a very high heat.
The gases generated by the burning of fresh fuel on, the fire-grate, and whose
temperature may be below the ignition point, are after admixture with air, highly
heated in passing through the flues a, ignition taking place and complete com-
bustion being effected by the time they reach the top of the section and before they
come into contact with the bare water tubes A in the succeeding section.
The flue spaces a between the rows of tubes may be inclined in various directions,
or they may be made vertical or staggered or otherwise disposed by varying the
order in which the blocks C are placed between the tubes. Our Invention may
also be applied to other forms of water-tube boilers than that illustrated in the.
Drawings.
By filling up the spaces between the tubes in the section over the furnace in the
manner shown, we form regenerators which absorb a considerable amount of heat
from the fire while it is bright, and part with a portion of such heat to effect
ignition of the rising gases evolved immediately after firing.
"
Having now particularly described and ascertained the nature of our said
Invention, and in what manner the same is to be performed, we declare that what
we claim is,―
First. The mode herein described of forming "regenerators" in the section or
sections of tubes over the furnace of a water-tube boiler, by filling up the spaces
between rows of the tubes with blocks of refractory heat-absorbing and retaining
material substantially as herein set forth.
Second. The combination with the tubes in a section or sections of a water-tube
boiler, of a series of refractory blocks so disposed between the rows of tubes as to
form with the tubes a series of regenerative flue spaces through which the furnace
gases pass, substantially as herein, set forth. -
Third. The construction of the brick or block C, substantially as and for the
purpose herein set forth.
Dated this Turentwirth law of Tui 7001
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