An Improved Method of Preparing and Applying Non-conductors of Heat.
Year: 1892

page_text: Date of Application, 22nd Oct., 1892
Complete Specification Left, 22nd July, 1893-Accepted. 26th Aug., 1893
PROVISIONAL SPECIFICATION.
An Improved Method of Preparing and Applying Non-conductors
of Heat.
I, GEORGE MITCHELL, of Albany Buildings, 47 Victoria Street, Westminster,
Engineer, do hereby declare the nature of my invention to be as follows:-
My invention relates to the covering or lagging of boilers, steam pipes, or other
surfaces with a non conducting material and is designed so that it may be easily
and expeditiously applied by the users own inexperienced labour, avoiding having
to get up steam in the boiler or pipes to dry the material on its application and to
avoid the general mess and inconvenience as at present to be contended with.
To carry my invention into effect 1 may use such non conductors of heat as are
at present applied moist in coats, such as silicious cement, fossil meal, or diatomite
as now in general use.
I place the same in a slightly damp state within moulds and subject it to pressure
by means of hydraulic presses or other method of pressing forming hard compressed
cakes or bricks of any required size or dimension. For boiler lagging for instance
the cakes would be moulded say:-three feet long by one foot broad of the required
thickness, convex on the outer side and concave on the inner to suit the diameter
of the boiler.
In the case of pipes the lagging would simply be the two halves of a circle in
suitable lengths and thickness.
These cakes or slabs of lagging are applied cold and fixed to the boilers or pipes
or other object, in the ordinary manner, by means of hoops with screws or canvas,
and may be taken off for inspection and replaced without injury as frequently as
required.
Where the cake or lagging is thin I provide for strengthening same by placing
within the mould with the unpressed material, expanded metal, wire gauze, netting,
cloth or woven material which when pressed forms a constituent part with the
material and is of the size of the cake pressed.
To render the cakes waterproof, I place first in the mould cloth or such material
rendered impervious to moisture or which have been dipped previously, in coal tar,
pitch, or such material. I then fill the mould with the non conducting material to
be pressed, and on the top of the material I place another cloth prepared as
described, and apply the pressure forming the cake.
My invention equally applies to pressing the material into larger and thicker
similar blocks for conveyance by land or water much decreasing its bulk and
consequently reducing the freight charges.
Dated this 22nd day of October 1899
FELL & WILDING,
1, Queen Victoria Street, London, E.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
An Improved Method of Preparing and Applying Non-conductors
of Heat.
I, GEORGE MITCHELL of 47 Victoria Street Westminster, Engineer, 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 covering or lagging of boilers, steam pipes or other

page_text: surfaces with a non-conducting material and is designed so that it may be easily
and expeditiously applied by inexperienced labour, avoiding having to get up steam
in the boiler or pipes to dry the material on its application, and to avoid the
general mess and inconvenience as at present to be contended with. Also by the
same treatment of the material increasing its density and decreasing its bulk for
shipment. To carry my invention into effect I may use such non conductors of
heat as are applied moist in coats, such as silicious cement, asbestos pulp, fossil
meal or diatomite.
The material to be worked is first made loose and slightly damp preferably
by steam directly applied thereto in a mixing machine from which it issues into
moulds and is subjected to pressure, preferably hydraulic, forming hard compressed
cakes or bricks of any required shape or dimension. For boiler lagging the cakes
could be moulded say three feet long by one foot broad of any required thickness,
convex on the outer side and concave on the inner side to suit the diameter of the
boiler. For pipes the lagging can be made in two halves of a circle or such shape,
in suitable lengths, and thickness. If the material pressed is of a fibrous nature
the cakes or slabs may be bent after pressing to suit the required shape.
These cakes or slabs of compressed lagging are applied cold by being fitted or
built on to the boilers or pipes or other objects; the joints or seams between the
cakes or slabs being closed with a soft plaster of the same material and smoothed
over, so as to make them adhere; finally the lagging is covered in the ordinary
manner by means of sheets, hoops with screws, or canvas and may be taken off
for inspection and replaced without injury as frequently as required.
Where the cakes or slabs are thin such as would be used for roofs and as a
substitute for wall-plaster also fire proof surfaces I provide for strengthening same
by placing within the mould, with the material to be pressed, expanded metal wire
gauze netting, cloth or woven material which when pressed forms a constituent
part with the material and size of the cake or slab.
To make the cakes or slabs "waterproof" I place first in the mould, cloth or
such material rendered impervious to moisture or which has been previously dipped
in coal tar, pitch, or such material; I then fill the mould with the material to be
pressed; and if necessary to waterproof the material on both sides I place on the
top another cloth prepared as described and apply the pressure forming the cake
or slab.
For shipment or other mode of conveying such material, I provide for making
the slabs thicker or in square blocks by the same process as described for the
lagging and which can be again broken up and repressed into cakes to suit any
requirement.
Having now particularly described and ascertained the nature of my inven-
tion and in what manner the same is to be performed, I declare what I
claim is
(1) The compressing into cakes or slabs of convenient size and thickness such
materials as are used for boiler or other covering applied moist substantially as
described.
(2) The covering of boilers, steam pipes or other surfaces with cakes or slabs
manufactured in the manner substantially as herein described.
(3) The making of fire-proof sheets of such material in the manner described and
set forth.
(4) The preparing for shipment or conveyance of such material in the manner
described.
(5) The saving of freight and transit charges by treating the raw or mixed
material practically as described and set forth.
GEORGE MITCHELL,
47, Victoria Street, Westminster, S. W.