Improvements in Evaporating Pans for the Concentration of Sulphuric Acid and other Liquids.
Year: 1894

page_text: Date of Application, 12th Nov., 1894-Accepted, 15th Dec., 1894
COMPLETE SPECIFICATION.
Improvements in Evaporating Pans for the Concentration of
Sulphuric Acid and other Liquids.
I, ISAAC SHIMWELL MCDOUGALL, of High Bank, Didsbury, in the City of
Manchester, Manufacturing Chemist, 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 :-
My invention relates to the concentration of sulphuric acid and other liquids, in
lead or other soft metal evaporating pans.
Hitherto it has been customary to lay the lead pan on solid metal plates often
protected by brickwork to prevent the heat warping or buckling the plates.
Because of this a mass of fire was required to produce the heat necessary for
concentration, and hence great cost was incurred for fuel, labour, and for wear
and tear.
The object of my invention is to overcome these difficulties, and so obtain great
economy.
My invention consists in applying perforated supporting plates and so allowing
the heat to come into direct contact on to the bottom of the evaporating pan.
The protecting plates for supporting the lead or soft metal evaporating pan may
be made either of cast or wrought metal, but I prefer cast metal.
The openings through the plates may be provided for in different ways; bars
may be laid with open spaces between, or the plates may have perforations, but I
prefer cast metal plates made of a grid pattern, and with diamond shaped holes as
I consider these the best suited to retain the metal of the pan and resist the
tendency of bedding to the plates by long working. Such openings also better
allow groovings which I provide on the surface of the plates, and permit them to
remain intact, these grooves running across both lengthways and by the width of
the plates. The groovings afford a better means for the heat distributing itself
under the bottom of the pan.
Referring to the accompanying sheet of explanatory drawings-
Figure 1 is a sectional elevation and Figure 2 a sectional plan representing the
general arrangement of my improved evaporating pan.
Figure 3 is an end view of the furnace, and Figure 4 a section on the line L M
Figure 1.
Figures 5 and 6 are sectional views representing the groovings in the perforated
olates.
The same reference letters in the different views indicate the same parts.
A is the lead or other soft metal evaporating pan.
B are the cast iron bearers for carrying supporting plates.
C are the perforated supporting plates.
D are the fire bars.
E is the syphon flushing arrangement.
F are the flues.
G is the overflow pipe.
H are the stay rods.
I is the outlet for fumes and other waste gases.
Jare grooves in the perforated plates, and
K is an opening in the brickwork.
By these devices it is found that the supported plates are kept sufficiently cooled
y direct contact with the metal of the pan. Less firing is required to keep
ulphuric acid or other liquid in a state of ebullition than by devices previously
J

page_text: employed, and so I ensure economy of fuel, less wear and tear, and a far greater
amount of work is done in the same time.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is―
1. In evaporating pans for sulphuric acid and like liquids, the use of perforated
supporting plates under the lead or other soft metal pan, or spaced supports of any
kind allowing the hot gases to impinge directly on the pan bottom as herein set
forth.
2. The evaporating pan with open metal supports having grooved faces as
herein before described with reference to the accompanying drawings.
. Dated this 9th day of November 1894.
MARKS & CLERK,
18, Southampton Buildings, London, W.C., Agents.