AN IMPROVED MATERIAL FOR COVERING STEAM BOILERS AND OTHER APPARATUS OR VESSELS FOR PREVENTING THE ESCAPE OR LOSS OF HEAT FROM THE SAME
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by William Robert Lake at the Office of
the Commissioners of Patents on the 9th April 1877. A communication from
abroad by Georges Hoppenstedt, of Paris, France.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "AN IMPROVED MATERIAL FOR COVERING
STEAM BOILERS AND OTHER APPARATUS OR VESSELS FOR PREVENTING THE ESCAPE
OR LOSS OF HEAT FROM THE SAME." A communication from abroad by Georges
Hoppenstedt, of Paris, France.
The substance now used for covering or "lagging" steam boilers, steam pipes, and
other parts of steam engines and similar apparatus, and which consists partly of
scoria or slag, or the like, and which is sometimes called mineral wadding, is a very
slow conductor of heat, it is absolutely incombustible, and is not in any way affected
by moisture, and but few of the acids or other chemical products can injuro it.
These qualities have rendered the said inaterial specially valuable as a non-conductor
of heat for covering steam boilers, locomotives, steam tubes, and the like, and it is
at present used to a great extent as a covering for delivery pipes.
The method now employed for applying the said so-called mineral wadding is
defective and somewhat costly, and is as follows, that is to say:-After having
placed a layer of the said so-called mineral wadding of suitable thickness, say, about
two inches and a half, upon a delivery pipe or other article it is compressed firmly
by the hand and secured by means of string or wire. The pipe or other article
having been thus covered for the length of several yards, the whole is covered with
bands or canvas, and then receives a coating of tar. The said so-called mineral
wadding has this defect, that when it is subjected to much pressure it becomes
reduced insensibly to powder. My said Invention is designed to remedy this
defect, and to dispense with the necessity of using bands or canvas.
In carrying my said Invention into practise, I cause the said so-called mineral
wadding to be steeped in a solution of silicate of soda or potash, more or less
diluted with water so as to form a sort of mortar. The said material being as
herein-before inentioned unaffected by moisture, that is to say, being always in a
capillary condition, remains as good a non-conductor of heat as before; I therefore
employ it in this condition of mortar or wet paste, in layers of varying thicknesses
according to the requirements of each particular case. In this condition of mortar
ΓΡ

page_text: or paste the said so-called mineral wadding may be applied to hot delivery pipes or
other articles, or to boilers under pressure as well as when they are cold. In either
case the adherence is perfect and immediate. In drying it becomes solid and
as hard as a stone, and it resembles pumicestone in its appearance and lightness.
It will be seen that by my said novel method of employing the so-called mineral
wadding, the latter does not become reduced to powder, as is frequently the case
when employing the method hitherto adopted of applying the said material
dry, and moreover I dispense with the string, the bands, the canvas, and the tar.
I do not confine myself to the use of the silicates of potash or soda, but may
use any silicates soluble in water, or I may employ any solutions of inorganic
matters, such as borax, alum, and the like, which will effect the same purpose.