IMPROVEMENTS IN HEATING, DRYING, AND EVAPORATING, AND IN APPARATUS TO BE USED THEREIN
Year: 1870

page_text: PROVISIONAL SPECIFICATION left by Christopher Rawson, Philip
Ovenden, and William McCree, at the Office of the Commissioners
of Patents, with their Petition, on the 24th December 1870.
We, CHRISTOPHER RAWSON, of No. 1, Saint Swithin's Lane, in the
City of London, General Manager of the Native Guano Company, and
PHILIP OVENDEN, of No. 17, Lyndhurst Road, in the County of Surrey,
Engineer, and William McCREE, of No. 2, Russell Road, Leyton, in the
County of Essex, Analytical Chemist and Engineer, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN HEATING, DRYING,
AND EVAPORATING, AND IN APPARATUS TO BE USED THEREIN," to be as follows:-
Our Invention consists of the means and apparatus herein-after
described for drying the mud or deposit obtained by the precipitation
of the impurities contained in sewage or refuse matters or liquids, for
the purpose of making manure therefrom, for drying peat and other
moist substances, for heating and evaporating liquids, and saline and
other solutions, and for similar purposes.
The essence of our Invention consists in applying heat both above
and below the substance, liquid, or solution to be dried or evaporated..
The arrangements by which we do this vary according to the nature of

page_text: the matter heated. In drying sewage deposit or mud, for instance, we
spread it on a floor, enclose it in a drying chamber, which floor is made
double, so as to constitute a flat steam space or chamber, through which
steam is caused to pass. The said steam is supplied at one end of the
steam chamber through a pipe communicating with a steam boiler and
escapes at the other end through a pipe leading to a flue or chimney
or to the open air. These pipes are furnished with stop-cocks or valves
for regulating or stopping the flow of the steam. Hot air is caused to
pass between the upper side of the floor and the roof of the drying
chamber, the said air being introduced at one end thereof through a
pipe or flue, and either passing from the other end through another pipe
or flue to the the chimney, or escaping through an opening into the
open air.
The mud or other substance treated is thus heated from
below by steam heat and from above by hot air, and is thus very rapidly
dried. Suitable openings or dampers are formed in the walls of the
drying chamber in order to regulate the heat thereof, and to allow the
steam given off by the substance being dried to escape, and the said
chamber is furnished with a door or man hole for giving access to the
workman, who spreads on the floor the substance to be dried, and
removes it from the said floor when dried. A dome top or shield of the
kind described in the Specification of Letters Patent granted to George
Edward Noone, and bearing date 25th April, in the year of our Lord
1866, No. 1163, may, if required, be mounted above the drying floor.
The hot air used may be taken from the furnace which generates the
steam to be passed under the drying floor or where the drying chamber
is near a steam boiler used for other purposes the waste steam from
such boiler and the waste heat from the furnace thereof may be used as
aforesaid. In this case the said heat may be taken from the chimney
or from the flue leading thereto, or where it is desirable to obtain heat
free from smoke atmospheric air is heated by means of air heating tubes
fixed side by side in a vessel which is mounted on or near the boiler,
and communicates therewith by means of pipes, through which the
steam passes to the said vessel where it circulates between the air-
heating tubes aforesaid. The outer ends of these tubes are open to the
atmosphere and the inner ends open into the hot air flue leading to the
drving chamber

page_text: tubes shall pass through them, and the air to be heated shall circulate
between the said tubes and then enter the hot air flue.
By either of the arrangements described we utilize the waste heat
of steam boilers and furnaces, and effect the rapid heating, drying, or
evaporation of various substances, liquids, or solutions.
Where solutions or liquids are to be operated upon an evaporating
pan or tray is substituted for the drying floor herein-before referred to,
the solutions or liquids therein being heated by steam under and hot air
over them, as herein-before described. The said solutions or liquids are
introduced and withdrawn through pipes furnished with stop-cocks, and
apertures are made in the sides of the drying chambers to permit of the
removal of any deposit resulting from evaporation.
Instead of using one drying floor or evaporating pan in the drying
chamber several of such floors or pans may be arranged therein, one
above another, the lowest of the series being heated by steam, as herein-
before described. The spaces between the said floors or pans commu-
nicate with each other by means of openings formed in the said floors
or pans at alternate ends thereof, and the hot air passes between the first
and second floors or pans from the front to the back end of the drying
chamber, thence through the opening in the second floor or pan between
that floor or pan and the third floor or pan to the front of the said
chamber until it has traversed the spaces between the series of floors or
pans, after which it escapes to the chimney or directly into the open air,
having in its passage heated the whole series of the said floors or pans.
By this arrangement we thoroughly utilize the hot air employed.