IMProve- MENTS IN THE MODE OF PREVENTING THE INCRUSTATION OF BOILERS
Year: 1874

page_text: LETTERS PATENT to David Clovis Knab, of Saint Denis, in the
Department of the Seine, France, for the Invention of "IMProve-
MENTS IN THE MODE OF PREVENTING THE INCRUSTATION OF BOILERS, AND IN
ealed the 23rd June 1874, and dated the 5th January 1874.
PROVISIONAL SPECIFICATION left by the said David Clovis Knab
at the Office of the Commissioners of Patents, with his Petition,
on the 5th January 1874.
I, DAVID CLOVIS KNAB, of Saint Denis, in the Department of the
Seine, France, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE MODE OF PREVENTING THE INCRUSTATION OF BOILERS, AND
IN THE APPARATUS CONNECTED THEREWITH," to be as follows:-
:-
A solution of carbonate of lime is precipitated with a proportionate
quantity of lime white, and the water for defecation is led by a conduit
to a continuous filtering apparatus consisting of 2, 3, 4, or more frames
of iron, zinc, or wood, similar in construction, and boxing one. within
the other, and either square, round, or other suitable form. Within

page_text: these frames a felt or other filtering substance is stretched, and when
the matter to be filtered is very tenuous a layer or layers of carded
cotton, having the filtering surface between two metal sheets is employed.
The water arriving at the first filter is clarified after passing through
the second and third ones.
When the water is very impure the first filter becomes choked; it is
consequently removed by levers or otherwise and cleansed in a water
bath.
The whole column of filters is raised mechanically or otherwise, and
under the last a clean filter is placed, the second becomes the first, the
others following in rotation. The more frequently the first filter is
removed the quicker the filtering is performed.
The water contained in the last filter still. holds sulphate of lime in
solution, unprecipitated by the lime water; nevertheless the water is
purified to the extent of 3. To prevent this sulphate from injuring the
heated sides of the generators, a proportionate quantity of ulmic acid is
added to the water, which prevents the agglomeration of the salts by
transforming them into mire.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said David Clovis Knab in the Great Seal Patent 2
Office on the 24th June 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DAVID CLOVIS:
KNAB, of Saint Denis, in the Department of the Seine, France, send
greeting.
WHEREAS Her' most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of January, in the year
of our Lord One thousand eight hundred and seventy-four, in the
thirty-seventh year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said David Clovis Knab, Her
special licence that I, the said David Clovis Knab, my executors, a
administrators, and assigns, or such others as I, the said David Clovis
Knab, my executors, administrators, and assigns, should at any time.
agree with and no others, from time to time and at all times thereafter

page_text: during the term therein expressed, should and lawfully might make,
exercise, use, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
",IMPROVEMENTS IN THE MODE OF PREVENTING THE INCRUSTATION OF BOILERS, AND
IN THE APPARATUS CONNECTED THEREWITH," upon the condition (amongst
others) that I, the said David Clovis Knab, my executors or admini-
strators, by an instrument in writing under my, or their, or one of
their hands and seals, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that I, the said David Clovis Knab, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement :-
All waters flowing on or through the soil contain calcarious salts in
solution, and they frequently hold foreign matters in suspension,
especially after heavy rain. These matters, in solution and suspension,
are the cause of serious inconvenience when the water is destined for
feeding steam generators, particularly locomotives. These matters not
being volatile accumulate in the generators and form very troublesome
incrustations or deposits, which rapidly lead to the destruction of the
'heated surfaces.
These drawbacks are completely obviated by the employment of the
process forming the subject of the present Invention, and which consists
of the following successive operations :-
1. After having tested the carbonate of lime in solution, it is pre-
cipitated with a proportionate quantity of lime white.
2. The precipitate produced, mixed with the matters in suspension, is
filtered by means of the apparatus shown in the accompanying Drawings,
Figs. 1 and 2.
This filter consists of 2, 3, 4, or more frames a, a, a, a, a,.
1111
of
wood, sheet iron, zinc, cast iron, or any other metal or material exactly
similar and boxing one within the other. At the lower end of each of these
frames a felt or other filtering stuff is stretched. When the matter to

page_text: be detained is very tenuous, this felt is replaced by a layer of carded
cotton, consisting of from 4 to 6 pieces, or in one piece, presenting a
filtering surface and placed between two metal sheets.
The water to be filtered is supplied at b at the upper part of the
column of the boxing frame. If the water does not filter very clear in
'the first frame a, the second a¹, or the third a", suffices to complete the
clarification.
When the water is very impure the first filter a is soon choked, and
then filtration greatly diminishes; without however awaiting this the
frame a is removed, and is readily cleansed by shaking it about in a
trough of water; then by aid of the levers 1, 1, or other mechanical
means the whole column is raised the height of one frame, and another
clean one is placed beneath the last one a¹¹. The frame a¹ thus takes the
place of that a just removed, that a" becomes a³, and so on successively.
A single person can work this apparatus with the greatest facility.
3. The clear or limpid water flowing from the last frame or filter still
contains calcarious salts in solution, and principally sulphate of lime. I
add therefore to this water before introducing it into the steam boiler a
solution which effectually prevents incrustation.
The composition of the solution is as follows:-In an iron boiler I
place 6 kilogrammes 250 grammes of the best turf as finely powdered as
possible, and diluted with 150 litres of ordinary water, rain water, or water
as pure as possible; I also add to the boiler 3 kilogrammes 150 grammes
of caustic soda, and the whole is borne to boiling point, whilst it is being
continually mixed. The turf almost entirely dissolves; it is allowed to
rest, and the clear liquid, which has a very deep brown colour, is then
decanted. The turf containing ulmic acid, ulmate of soda is formed,
containing the azote matters of the soda. An equal weight of this
solution is employed in proportion to the quantity of salt of lime con-
tained in the water.
In presence of the sulphate of lime, soluble sulphate of soda is formed
of the ulmate of lime, besides the organic ligneous matter of the turf
prevents the deposits from agglomerating and forming incrustations.
I reserve to myself the right to employ in place of the natural turf
the extract of ulmate of ammonia, as well as the extract of all organic
salts producing the same result, such as phenate of ammonia or soda
extracted from turf tar or coal tar.

page_text: My Invention rests therefore in the combination of the three opera-
tions already described, and specially,―
1st. In the rapid filtration of water by aid of the apparatus described,
which may be of variable form and dimensions.
2nd. In the employment of pulverized turf, which acts chemically and
mechanically on the incrustations, and also in the use of the extract of
organic salt, which can be extracted from it, and which then only acts
in a chemical manner on the incrustations of steam generators.
In witness whereof, I, the said David Clovis Knab, have hereunto
set my hand and seal, this Twenty-second day of June, in the
year of our Lord One thousand eight hundred and seventy-four.
A TRAD