Improvements in the Means of Arresting Dust after Combustion in Destructors.
Year: 1893

page_text: Date of Application, 7th Nov., 1893
Complete Specification Left, 7th Aug., 1894-Accepted, 3rd Nov., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Means of Arresting Dust after Combustion in
Destructors.
STEPHEN HARDING TERRY, and REGINALD EMPSON MIDDLETON, Engineers,
both of 17 Victoria Street, Westminster, London, S.W. do hereby declare the
nature of this invention to be as follows:-
This invention has for its object the arrest, collection, & removal of the floating
particles of dust and other matters which have not been volatilised in the destructor
whether from insufficient heat or imperfect combustion or from the refractory.
nature of the substance, whilst from the small size & high temperature of the
particles & gases any attempt to arrest the progress of the solid particles by
previous methods has hitherto failed.
This invention consists of the grouping (at suitable intervals) of screens
perforated or imperforate of sheet steel, boiler plate or other suitable material, as
for instance fire clay slabs, firebrick walls, asbestos or other substance the
material being fixed at certain angles so as to produce (when the heated gases pass
over their top or under their bottom edges) vortices & still places in which the
motion of the air is insufficient to carry ordinary dust & in consequence deposition
takes place until a considerable depth has accumulated when the dust may be
removed through side doors, or by other means.
sprays
The apparatus may be in duplicate or triplicate having, always one route
of
available to the chimney, & further purification may take place by means
of water & wet screens or trays or by steam jets which with air jets. may be used
to deflect the current under or over the screens.
1.
Dated this 6th day of November 1893.
Improvements in the Means of Arresting Dust after Combustion in
Destructors.
3%
We, STEPHEN HARDING TERRY, and "REGINALD EMPSON MIDDLETON,
Engineers, both of 17, Victoria Street, Westminster, in the County of London,.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:.
:
This invention has for its object the arrest, collection and removal of the floating
particles of dust and other matters, which have not been volatilised in the destructor,
whether from insufficient heat or imperfect combustion or from the refractory
nature of the substances, whilst from their small size and high temperature, any
attempt to arrest their progress by previous methods has failed.
This invention consists of the grouping in closed chambers formed in the main
flue at suitable intervals apart of screens or deflectors perforated or imperforate
and made of sheet steel, fire brick, or other suitable material, fixed at certain
angles so as to produce, when the heated gases pass over their top edges or under
their bottom edges, vortices and still places in which the motion of the air is
checked and rendered insufficient to carry ordinary dust and in consequence
D

page_text: deposition takes place, until a considerable depth has accumulated, when the dust
may be removed through side doors. *
The apparatus may be in duplicate or triplicate, baving always one route
available to the chimney, and further purification may take place by means of
sprays of water, wet screens or trays. Suitable doors lined with fire bricks if
necessary are provided in the sides for the removal of ashes and dust.
We will further describe our invention in reference to the accompanying drawing
in which
•
Fig. 1 is a sectional plan of a duplex arrangement,
Fig. 2 a longitudinal section on centre line of one chamber, and Fig. 3 a cross
section on line 1-2 of Fig. 2.
The products of combustion from the destructor cells (which are not shown) pass
by the main flue A over a catch pit C in which the larger particles of dust are
deposited by reason of the reduction in the velocity of the current due to the
sudden increase in the area of the flue. The pit C is provided with suitable
doors D for the removal of dust so deposited. B represents a boiler which may
with economic results be set in an enlargement of the flue A adjacent to the pit C
for utilizing the waste heat (but this forms no part of our invention). Beyond the
boiler if used or if not used beyond the pit C, the flue area is enlarged so as to
form the main depositing chamber E which is divided up at its lower part by
cross walls el into any desired number of compartments e, e, e. The upper part of
the chamber is made of continually increasing area either by vertical enlargement
as illustrated, or by borizontal enlargement, or by both vertical and horizontal
enlargements. In this chamber are arranged the inclined deflecting screens F F
which may be in the form of arches adapted to carry the roofing, and also a series
of flat steel plate or fire clay screens G G; these latter, may all be inclined at a
uniform angle of from 30° to 45°, but we find it advantageous to incline the first
one at an acute angle of about 10° and the last at an angle of about 85° with the
horizontal, the intermediate ones being inclined successively with gradually
increasing angularity from first to last. J J are a final' series of flat transverse
inclined screens beyond which the chamber is reduced in area and leads to the
chimney flue L. By this arrangement the gases from the destructor are deflected
by the upper angled screens F F and directed on to and between the intermediate
transverse angled screens 'G in such manner as to form vortices and still places
wherein eddies are set up and cause a deposition of dust in the lower compartments e, e,
of the chamber E, the gases thus purified of much suspended dust then pass
between the screens J, J, which cause in a similar manner a further deposition, and
finally escape to the chimney through flue L.
In order to still more fully purify the gases we may use in combination with the
above described arrangement a water curtain produced by means of a perforated
pipe I arranged across the top of the chamber E from, which a stream of water
falls continuously over the screens J, J, and flows into a tank K; thus such
suspended dust as still remains before the gases pass to the chimney is washed out.
Suitable openings H, H, fitted with doors, are provided for the removal of dust
deposited in the lower parts of the chamber E.
:
I
Any number of chambers (and boilers if desired) may be used, either separately
or in combination, the flow of the gases being regulated by means of dampers
arranged in the usual manner as at M.
An alternative construction is shown in Figs. 4 and 5, which are respectively a
vertical and a horizontal section of the arrangement. In this case in the closed
chambers F and C formed in the main flue we arrange instead of the flat inclined
screens above described circular inclined screens, more or less like inverted cones,
surrounded by annular catch pits. The products of combustion from the destructor
cells, entering by the main flue A are caused to pass upwards in the chamber C
through the outwardly inclined screen B, the velocity being checked by the
increase in area of the passage B. A portion of the dust held in suspension is
deposited in the exterior annular pit b, the gases then pass on through flue D and

page_text: up a similar but larger circular inclined screen E, depositing as before, owing to
increasing area, in the exterior pit e.
The depositions of dust may be made more or less complete by increasing the
number of such circular screens and chambers to any desired extent. The last
chamber of the series provided with an outlet flue G leading to the chimney in
the usual manner. The outlet flue is preferably constructed at a height above the
base sufficient to prevent any disturbance of the dust which may have accumulated
in the last chamber.
Suitable openings H, H, fitted with doors are provided in such positions as may
be most convenient, to facilitate the removal of dust from the several flues and
chambers.
For further purifying the gases we may employ a circular perforated pipe J
arranged so as to direct a jet of water or steam upon the edge of the last circular
screen E in such a manner as to form a curtain to remove any dust which may not
have been previously deposited in the chambers.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. The means of arresting dust after combustion in destructors consisting in the
arrangement at suitable intervals apart of inclined screens such as are above
described, in closed enlarged chambers provided with catch pits and formed in the
main flue in such manner as to produce vortices or still places in the current of
gases from destructor to chimney, whereby deposition of dust and fine particles is
effected substantially as above set forth."
2. In apparatus such as is above referred to the arrangement in combination
with certain of the inclined screens of a water curtain for effecting the more
complete purification of the gases, substantially in the manner set forth.
3. The several arrangements of our apparatus, substantially as herein shown
respectively in Figs. 1 to 3 and Figs. 4 and 5.
Dated this 7th day of August 1894.