IMPROVED SANITARY APPARATUS OR ARRANGEMENTS FOR PREVENTING NOXIOUS EXHALATIONS SUCH AS ARISE WHEN COATING OR TREATING IRON OR OTHER ARTICLES
Year: 1865

page_text: PROVISIONAL SPECIFICATION left by Matthew Andrew Muir and James
MIlwham at the Office of the Commissioners of Patents, with their
Petition, on the 24th June 1865.
We, MATTHEW ANDREW MUIR and JAMES MILWHAM, of Glasgow, in the
County of Lanark, North Britain, Machinists, do hereby declare the nature of
the said Invention for "IMPROVED SANITARY APPARATUS OR ARRANGEMENTS FOR
PREVENTING NOXIOUS EXHALATIONS SUCH AS ARISE WHEN COATING OR TREATING IRON
OR OTHER ARTICLES," to be as follows, that is to say:-
The
This Invention has for its object the prevention of the noxious exhalations
hitherto, attending various manufacturing processes, and it is applicable in all
or most cases in which the exhalations are of a combustible character.
coating of iron or other articles with tar or tarry mixtures or with oil or paint
with the aid of heat involves the production of noxious exhalations of the kind
referred to, and the peculiarities of the improved apparatus or arrangements
are embodied in modifications specially designed for coating iron articles with
tar or the like, and herein-after described.
Two modes of coating iron with tar are practised; in one the article in a
cold state is immersed in the heated tar and kept in it until it becomes as hot
as the tar; whilst in the other mode the article is heated before immersing it,
and in this case it is dipped into the tar and instantly taken out again. When

page_text: the articles are to remain in the tar for a little time, a deep boiler or heating
tank is employed, and is provided with one modification of the improved
sanitary apparatus. The tank is, by preference, square or rectangular in
plan, and is fitted with a compound cover consisting of nine or other con-
venient number of separate doors; only one of these doors is opened at one
time for the removal and introduction of the iron articles. When the form
and size of the articles admits of it a number of them are arranged upon a
branched stalk which is lowered into the tank by means of a crane. The
doors are opened in regular succession, and by the time articles have been
introduced through the whole of the openings those put in at the first one will
have been long enough in the tar, and can be removed and fresh ones can be
put in. The operations of immersing and removing can thus be carried on
continuously, whilst never more than one-ninth or other small part of the tank
is uncovered at one time. The reducing of the uncovered space in this way
facilitates the prevention of exhalation by appliances yet to be described.
A duct or flue is formed round the tank at a height a little above the level
of the tar, and a branch passes down therefrom to the ashpits of the double
furnace by which the tank is heated, the fronts of the ashpits being closed by
doors. A number of openings are made round the sides of the tank into the
duct, and these openings are proportioned and distributed so as to cause the
vapour or exhalation from the heated tar to be drawn into the duct as
uniformly as possible from all parts of the tank. The furnace draught causes
the vapour to be drawn into the duct and thence through the fires where it is
burned. Any liquid condensing in the duct is received in a basin or pocket
formed for it in the lower part of the duct, and is thereby prevented from
entering the ashpits, where it would take fire. The vapour is very completely
burned in the furnace, and is thereby converted into the ordinary products of
combustion. The flues from the furnace are made to encircle the tank, but
an additional passage is provided in direct communication with the chimney,
and this passage is fitted with a damper or valve. At night or at other times
when the work is suspended the direct communication is opened, and the fire
can in consequence be kept in without heating the tar sufficiently to produce
the least exhalation; this is important, as it permits of the fire being got to a
state of full activity with the least possible loss of time when recommencing
to work. The operations are further facilitated and loss of time avoided by
indexing the traverse movement of the crane so that it can be set accurately
and rapidly to each of its successive positions. A turntable is also provided,
upon which the stalks or carriers of the goods are placed, this table being
gradually moved round, and giving time for each set of articles to have the

page_text: coating sufficiently hardened for the removal of the articles before each stalk
or carrier comes round to the position for receiving a fresh set.
The mode wherein the iron article is heated before immersion in the tar is
conveniently applicable in the case of railway gauge bars. These bars are
carried from the fire whereon they are heated, and are dipped in a horizontal
position into a trough containing tar, and are then laid on rests for the super-
fluous tar to drip from them. The dipping trough and dripping rests are
arranged conjointly, and occupy a rectangular space, and this space is covered
by a hood, a duct from which communicates with any convenient furnace the
draught of which is taken advantage of for drawing off and burning the
noxious vapours rising from the hot freshly-coated articles. The hood is sus-
pended so that the articles can be moved by means of hooks continuously
under it being entered at one side and being removed at the opposite side
after remaining some time on the dripping rests. An important feature of
the hood is a horizontal diaphragm with which it is fitted inside a little above
its bottom edges, this diaphragm being formed with a number of perforations
which cause the draught to act uniformly over all parts of the space covered
by the hood. With these arrangements a very moderate draught suffices for
collecting and drawing in all the noxious vapours, and for conveying them
to the furnace wherein they are converted into ordinary products of com-
bustion.
Apparatus or arrangements, substantially such as are herein-before described,
are obviously applicable in all manufacturing operations which are accom-
panied by the exhalation of noxious vapours when such vapours are of a com-
bustible nature, but the details of the arrangements will necessarily be
modified to suit each particular case.