DESICCATION OF THE AIR SUPPLY OF FURNACES AND APPARATUS FOR THAT PURPOSE
Year: 1884

page_text: I, CHARLES COCHRANE of The Grange, Stourbridge in the county of Worcester,
Ironmaster, do hereby declare the nature of my invention for "DESICCATION OF
THE AIR SUPPLY OF FURNACES AND APPARATUS FOR THAT PURPOSE" to be as
follows:
For many furnace operations, particularly those in which a hot blast is employed,
it is of great advantage to supply air with as little moisture as possible dissolved
or suspended in it. My invention relates to means of desiccating the air supply of
furnaces, I cause the cold air on its way to the heating stove or furnace to pass up
a tower or such like structure through a number of screens and gratings. At the
top of the tower there is a feed apparatus constructed as an air lock by which
charges of what is known as "commercial calcium chloride" (not that which is
fused) are from time to time admitted to fall on conical distributors by which the
chloride is scattered over the uppermost set of gratings which have the largest
openings through them. The gratings below these have holes of less size, the holes
being less and less, the lower the grating, until the lowest is reached, having holes
about an inch square. Below these gratings are fixed wooden screens each consisting
of a number of trapezoidal bars of wood laid with their wide faces uppermost
parallel to one another, the bars of the one screen crossing those of the next screen
in order. The air in passing up through these screens and gratings has its moisture
absorbed by the calcium chloride, which is thereby gradually converted from a solid
to a liquid condition, in which it trickles down over the before mentioned bars.
The moist incoming air supply being thus brought into intimate contact with very
extended surfaces over which the solution of calcium chloride flows, the latter
although the solution is saturated with calcium chloride is still enabled to take up
moisture from the air to a very large extent, and thus the efficient desiccation of
the air can be effected with a comparatively small quantity of calcium chloride.
By this means, not only is the cost of material rendered comparatively small but
the labor of conveying the solidified calcium chloride from the evaporating pans,
where it has to be revivified, back to the desiccating apparatus, is greatly reduced.
The calcium chloride solution may be conveniently raised from the bottom of the
desiccating apparatus to the tank of the evaporating apparatus at a higher level
by the pressure of the air blast itself or in any convenient known manner.
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,
London, W.C.

page_text: COMPLETE SPECIFICATION,
I, CHARLES COCHRANE of The Grange, Stourbridge in the County of Worcester,
Ironmaster,. do hereby declare the nature of my invention for "DESSICATION OF
THE AIR SUPPLY OF FURNACES AND APPARATUS FOR THAT PURPOSE" and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement :-
For many furnace operations, particularly those in which a hot blast is employed,
it is of great advantage to supply air with as little moisture as possible dissolved
or suspended in it. My invention relates to means of dessicating the air supply of
furnaces. I cause the cold air, on its way to the heating stove or furnace after or
before entering the blast engine, to pass up a tower or such like structure through
a number of screens and gratings. At the top of the tower there is a feed
apparatus constructed as an air lock by which charges of what is known as
"commercial calcium chloride" (not that which is fused) are from time to time
admitted to fall on conical distributors by which the chloride is scattered over the
uppermost set of gratings which have the largest openings through them. The
gratings below these have holes of less size, the holes being less and less the lower
the grating until the lowest is reached, having holes about an inch square. Below
these gratings are fixed wooden screens each consisting of a number of trapezoidal
bars of wood laid with their wide faces uppermost parallel to one another, the bars
of the one screen crossing those of the next screen in order. The air in passing up
through these screens and gratings has its moisture absorbed by the calcium
chloride which is thereby gradually converted from a solid to a liquid condition,
in which it trickles down over the before mentioned bars. The moist incoming
air supply being thus brought in contact with very extended surfaces over which
the solution of calcium chloride flows, the latter being saturated with calcium
chloride is still enabled to take up moisture from the air to a very large extent, and
thus the efficient desiccation of the air can be effected with a comparatively small
quantity of calcium chloride.
By this means, not only is the cost of material rendered comparatively small but
the labour of conveying the solidified calcium chloride from the evaporating pans,
where it has to be revivified back to the desiccating apparatus is greatly reduced.
The calcium chloride solution may be conveniently raised from the bottom of the
desiccating apparatus to the tank of the evaporating apparatus at a higher level by
the pressure of the air blast itself or in any convenient known manner.

page_text: top by a hinged cover D¹ and at the lower end by a hinged bottom D, through
which charges of solid calcium chloride are from time to time introduced into
the casing, where it falls on to the conical distributing grating E by means of
which it is distributed over the flat gratings F F below. The uppermost of these
gratings are formed with openings of large size while in the lower gratings the
openings gradually become less and less, the gratings being at the same time placed
nearer and nearer together as shewn. Beneath the gratings are fixed a number of
wooden screens G G consisting each of a number of trapezoidal bars of wood laid
with their wide faces uppermost, parallel to one another, the bars of the one screen
crossing those of the contiguous screens above and below. Thus as the solid
calcium chlorido falls from one grating to another it comes in contact with the
rising current of air entering at B, and absorbs the moisture therefrom. In pro-
portion as it absorbs the moisture, the calcium chloride becomes gradually converted
from the solid to the liquid condition, so that the pieces thereof become gradually
reduced in size and consequently fall through the openings of one grating on to the
grating with smaller openings below, until at the lower gratings it has become
entirely converted into the liquid condition, and consequently drips down over the
very extended surfaces offered by the screens G; arrived at the bottom of these,
the liquid calcium chloride, diluted to such an extent that it will not take up much
more moisture from the air, falls into the bottom of the chamber A, whence it is
withdrawn through the pipe H, to be conveyed to any suitable evaporating
apparatus where it is reconverted into the solid form, in order to be used over
again.
It will be seen that by the above described arrangement the air containing most
moisture is brought in contact with the calcium chloride solution that has already
absorbed most moisture, while the more or less dried air is brought in contact with
the fresh calcium chloride at top, so that by this well known action of reversed
currents the moisture is taken up from the air with the least expenditure of calcium
chlorido.
I is a glass gauge for observing the height of liquid calcium chloride in the
chamber A, and K is a man-holo for gaining access to the interior of the
chamber.
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, The method substantially as herein described of desiccating the air supply of
furnaces by causing it, on its way to the furnace, heating stove or blowing engine,
to pass in intimate contact with extended surfaces of a substance such as calcium
chloride that will take up moisture therefrom.
2, The use for desiccating the air supply to furnaces by means of calcium
chloride of apparatus constructed and operating substantially as herein described
with reference to the accompanying drawing.