IMPROVEMENTS IN LAGGING FOR COVERING STEAM BOILERS, PIPES, AND OTHER ARTICLES
Year: 1884

page_text: We, WILLIAM LAWSON THOMPSON of N° 28 Martin's Lane, Cannon Street, in the
City of London, Engineer, and JoHN CHARLES WILLIAM STANLEY, of N° 28 Martin's
Lane, in the City of London, Gentleman, do hereby declare the nature of said in-
vention for "IMPROVEMENTS IN LAGGING FOR COVERING STEAM BOILERS, PIPES, AND
OTHER ARTICLES," to be as follows:-
The object of this. invention is to prevent radiation of heat from and consequent
condensation of steam in steam boilers, steam pipes, cylinders or other vessels; also
to prevent loss of heat generally from exposed surfaces and in some cases consequent
freezing. For such purposes it has been usual to apply compounds of various kinds
having the quality of being bad conductors of heat, such as Asbestos, Silicate Cotton,
Wool, and hair felt and plastic compounds. It is well known that if a heated surface
be surrounded by an external covering so as to enclose air between such heated
surface and covering, radiation of heat from the heated surface will be prevented or
retarded. furthermore that a vessel having an external bright surface either tinned
or silvered will more effectually retain the temperature of its contents than a vessel
having a blackened surface.
Now our invention is designed to produce lagging presenting the advantages due
to an enclosed air space and a bright surface.
We have ascertained by experiment that porous materials such as bair felt,
Silicate Cotton, Asbestos and the like, holding air in the fibres are much better
non-conductors of heat than dense plastic compounds, or ordinary felt as they form
air reservoirs.
In carrying out our invention we take felt composed of wool or wool and cotton
fibres or Asbestos cloth or paper and corrugate the same by passing it between
grooved or fluted rollers. Where the surface to be covered is subject to a high
temperature it will usually be advantageous to use asbestos cloth-In preparing a
lagging for vessels such as Boilers, Brewers Vats and the like, the corrugated felt or
cloth is cut into sheets of appropriate shapes and sizes, and these sheets are laid one
over another with the corrugations of one at right angles to those of the sheets next
it, until the desired thickness is attained (say from one to two inches more or less).
By this arrangement cells or passages constituting air reservoirs are produced
D

page_text: between the sheets or layers. At the inner side of the compound coating thus
formed we provide ribs or strips of asbestos, (these may be about an inch in
thickness) which are fixed by rivets or ties passing through the several corrugated
sheets or layers. In some cases we provide at the outer side a metallic plate or
surface which may be of tinned iron or tin-foil paper It can be fixed by the rivets
or ties that hold on the Asbestos ribs or strips. In some instances the bright
metallic surface may be dispensed with, but its use will aid materially in preventing
loss of heat by radiation. The metallic outer covering is made to extend beyond
the edge of the compound covering of corrugated felt or cloth on all sides. If
corrugated felt be used it will be advantageous to dip it in a solution of Silicate of
Soda When fixing the above described lagging or covering to a heated or other
surface the ribs or strips are coated with an adhesive compound to cause them to
adhere and the overlapping metallic margins are soldered at the joints. For covering
steam pipes we use material corrugated as above described, but instead of arranging
the sheets or layers with the corrugations of one across those of another, we roll the
corrugated material one thickness over another around a core somewhat larger in
diameter than the pipe intended to be covered. When the desired thickness of
corrugated material has been thus rolled around the core it is severed from the rest
and the end fastened, then the core is removed-and the lagging is cut down one
side, a bright metallic external covering can be attached in the manner already
described above, but to give it a round form is first passed between a pair of rollers.
As it is important to be able to discover a leak in a lagged vessel the external bright
metallic covering can be perforated with fine holes in places so as to allow escaping
fluid to be seen.
-
Where large surfaces have to be covered it will be found necessary to have
suitable metallic rings or clamps (which may be of tinned hoop iron) clamped
around to hold the covering in place.

page_text: We, WILLIAM LAWSON THOMPSON of No 28 Martin's Lane Cannon Street, in
the City of London, Engineer, and JOHN CHARLES WILLIAM STANLEY of No 28
Martin's Lane, Cannon Street in the City of London, Gentleman, do hereby
declare the nature of our invention for IMPROVEMENTS IN LAGGING FOR COVERING
STEAM BOILERS, PIPES AND OTHER ARTICLES and in what manner the saine is to
be performed, to be particularly described and ascertained in and by the following
statement:-
The object of this invention is to prevent radiation of heat from and consequent
condensation of steam in steam boilers, stenm pipes, cylinders, or other vessels ;
also to prevent loss of heat generally from exposed surfaces and in some cases
consequent freezing. For such purposes it has been usual to apply compounds of
various kinds having the quality of being bad conductors of heat, such as Asbestos,
Silicated Cotton, Wool, and hair felt and plastic compounds. It is well known that
if a heated surface be surrounded by an external covering so as to enclose air
between such heated surface and covering radiation of heat from the heated surface
will be prevented or retarded, furthermore that a vessel having an external bright
surface either tinned or silvered will more effectually retain the temperature of its
contents than a vessel having a blackened surface.
Now our invention is designed to produce lagging presenting the advantages
due to an enclosed air space and a bright surface.
We have ascertained by experiment that porous materials such as hair felt,
Silicate Cotton, Asbestos and the like holding air in the fibres are much better
non-conductors of heat than dense plastic compounds, or ordinary felt as they form
air reservoirs.
In carrying out our invention we take felt composed of wool, or wool and cotton
fibres or Asbestos cloth or paper and corrugate the same by passing it between
grooved or fluted rollers. Where the surface to be covered is subject to a high
temperature it will usually be advantageous to use asbestos cloth-In preparing a
lagging for vessels such as Boilers, Brewer's Vats and the like, the corrugated felt
or cloth is cut into sheets of appropriate shapes and sizes, and these sheets are laid
one over another with the corrugations of one at right angles to those of the sheets
next it, until the desired thickness is attained (say from one to two inches more or
less), or one or more sheets of thick felt are corrugated and are placed between
thinner sheets uncorrugated on either side thus combining the advantages of air
spaces and nonconducting material as before stated. By this arrangement cells or
passages constituting air reservoirs are produced between the sheets or layers. At
the inner side of the compound coating thus formed we provide ribs or strips of
Asbestos, (these may be about 1/, an inch in thickness) which are fixed by rivets or
ties passing through the several corrugated sheets or layers. In some cases we
provide at the outer side a metallic plate or surface which may be of tinned iron
or tin-foil paper. It can be fixed by the rivets or ties that hold on the Asbestos
ribs or strips. In some instances the bright metallic surface may be dispensed
with, but its use will aid materially in preventing loss of heat by radiation. The
metallic outer covering is made to extend beyond the edge of the compound
covering of corrugated felt or cloth on all sides. If corrugated felt be used, it will
be advantageous to dip it in a solution of Silicate of Soda-When fixing the above.
described lagging or covering to a heated or other surface the ribs or strips are
coated with an adhesive compound to cause them to adhere and the overlapping
metallic margins are soldered at the joints.

page_text: For covering steam pipes we use material corrugated as above described, but
instead of arranging the sheets or layers with the corrugations of one across those
of another, we roll the corrugated material one thickness over another around a
core somewhat larger in diameter than the pipe intended to be covered. When the
desired thickness of corrugated material has been thus rolled around the core it is
severed from the rest and the end fastened, then the core is removed, and the
lagging is cut down one side, a bright metallic external covering can be attached in
the manner already described above, but to give it a round form is first passed
between a pair of rollers. As it is important to be able to discover a leak in a
lagged vessel the external bright metallic covering can be perforated with fine holes
in places so as to allow escaping fluids to be seen.
Where large surfaces have to be covered it will be found necessary to have
suitable metallic rings or clamps (which may be of tinned hoop iron) clamped
around to hold the covering in place.
Having now particularly described and ascertained the nature of our said
Invention, and in what manner the same is to be performed we declare that
what we claim is:-
(1) The combination and arrangement and construction of Lagging for covering
steam boilers, pipes, and other articles substantially as hereinbefore described.
(2) The use of Corrugated hair felt, Silicated Cotton, Asbestos, mixed felt, of
wool and hair, or wool and cotton fibre, and the like substantially as herein before
described.
(3) The building up of the lagging of different thickness of material the
corrugations being parallel or crossed at right angles or diagonally, substantially as
herein before described.
(4) The use of a Metallic Plate affixed to the outside of the lagging substantially
as herein before described.
.
(5) The securing of the different component parts of the lagging by rivets,
wire, hoops, clamps or other suitable device substantially as herein before described.
(6) The use of strips or ribs of Asbestos on the inner side of the compound
coating or lagging, and the use of silicate of soda or other similar substance to
render the lagging less liable to injury by the heat substantially as herein before
described.
JANaramba 1904.