Improvement in Non-conducting Coverings for Boilers, Steam, Hot Air and Hot Water Pipes and the like.
Year: 1893

page_text: Date of Application, 23rd May, 1893-Accepted, 15th July, 1893
COMPLETE SPECIFICATION.
Improvement in Non-conducting Coverings for Boilers, Steam, Hot
Air and Hot Water Pipes and the like.
A communication from abroad by HENRY CARR GOODELL, Manager of Goodell
California Fruit Line, Atchison, Atchison County, Kansas, and WILLIAM
EVARTS RICHARDS, Patent Agent, of 203 Broadway, New York, in the
County and State of New York.
I, JOHN CORRY FELL, of the Firm of Fell & Wilding, of 1, Queen Victoria
Street, in the City of London, Patent Agent, 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 :-
The object of our invention is the more perfect insulation of the surfaces of
boilers, steam, hot air, and hot water pipes, and other structures, for the purpose
of preventing loss of heat by radiation and conduction. The invention is broadly
applicable wherever this end, i.e. the non-conduction of heat is desired.
Our invention consists:
First In the employment of a material for non-conducting coverings that is we
believe, a far better non-conductor of heat than any material heretofore used for
this purpose. It is well known that lampblack is one of the most effective non-
conductors known. We have, however, discovered that the many kinds of
lampblack commercially sold and used differ very greatly as to their conductive or
non-conductive powers. We have found by experiment that lampblack produced
from natural gas is not a good non-conductor, and that other forms of lampblack
differ very widely in their non-conductive powers. We have also found by
experiment that lampblack produced from heavy oils or crude petroleum is the
best non-conductor, and in our covering, as hereinafter described, we employ a
lampblack made from heavy oils and find that we secure better results than have
been known heretofore.
Second It is characteristic of lampblack, that it repels moisture, and that it
cannot readily be incorporated with other materials. For these reasons it has
heretofore been difficult to form, with lampblack as an ingredient, a hard and
compact covering that would not crumble or fall to pieces in use.
After a long series of experiments, we have found that by the use of certain
filling and binding materials lampblack can be successfully incorporated into a
plastic mixture which, when applied to the exterior of boilers or other structures,
will adhere well and will neither break to pieces nor crumble with use.
Our invention therefore consists in the employment of other ingredients with
lampblack which, when thoroughly commingled, will retain the lampblack, and the
whole form a firm and durable covering.
Third: It has heretofore been difficult to employ a plastic compound for covering
steam, hot air, and hot water pipes, for the reason that it is difficult to apply a
plastic compound to these small surfaces, especially in the places where such pipes
are usually found, and it has not been heretofore practicable to mould these plastic
compounds into sectional form, for the reason that, it being impossible to make
such hard sections fit accurately to the surface of the pipe, air spaces of greater
or less extent were formed between the pipe and these sectional coverings, through
which the hot air would escape at the joints and at the ends of the sections, thereby
defeating the purpose of the covering.
Our invention therefore has for its further object, to produce a moulded sectional
covering which shall be free from the objections above referred to, and which can
be eninloved for covering stand and running pipes of all descriptions.

page_text: Fourth Our invention further consists in the utilization as a body material of
what has heretofore, been waste products, thus greatly reducing the cost of the
covering, whilst at the same time we find that by the use of certain waste substances
we are enabled to make a more compact, durable and efficient covering than
heretofore possible.
Fifth Our invention also has for its object to produce a covering material in
such a way that it may be thoroughly mixed and then transported from place to
place, in a dry state, and when required for use may be simply wetted with water
and applied as desired.
Referring now to the drawings, which form a part of this Specification:
Figure 1 is a view in perspective, of a portion of a boiler, having applied thereto
a covering formed in accordance with our invention.
Figure 2 is a cross section of a portion of a pipe having applied thereto a
sectional covering formed in accordance with our invention. In this view a quarter
section is shown as uplifted from the pipe.
Figure 3 is an enlarged view of a piece of sponge showing the cellular tissue
and the character of its fibres.
Figure 4 is a view of the sponge in Figure 3 showing the cells of the sponge
as filled with lampblack.
In carrying our invention into effect we first form what is known as lime-putty,
which is done by taking a good quality of freshly burnt lime, thoroughly slacking
it with water, and allowing it to stand for from one to two weeks, or even longer,
until it forms a smooth, even, pasty mass, in which the lime is thoroughly
disintegrated and slacked.
We have found that lime-putty forms a very much better and more reliable
binding material than freshly slacked lime, as in the latter will often be found
large particles, or lumps of lime, which have not been thoroughly slacked, and the
presence of which in the finished covering, will often be productive of crumbling,
and its partial or entire destruction.
We have also found that the lime-putty will better receive, and more completely
and intimately commingle with the lampblack and fibre than freshly slacked lime,
and that therefore it produces a better and more durable covering.
We then add to the lime-putty about an equal quantity in bulk of what we term
a body material, and we have found that we can use to great advantage for this
purpose certain substances which have heretofore been waste products, such as
sponge waste, which is composed of the clippings found when dressing sponges for
the market; the waste pulp from paper mills; the sweepings of rope walks,
carpet mills, and like manufactories, the latter being composed of a mixture of long,
strong fibre, with a mass of short finely divided fibre, with of course more or less
other waste material, all of which, if not too coarse, may be utilised as a filler or
body material, the larger fibre being cut if necessary to a proper length. We have
found in practice that this fine fibre when thoroughly mixed with the other sub-
stances of our non-conducting covering forms a more intimate intermixture with
the lime-putty and lampblack, and produces a more compact durable, elastic and
generally more satisfactory covering than any other material, whilst by its use the
cost of the covering is greatly reduced. Should the waste substances, such as
above specified, not contain a sufficient amount of long fibre to bind the covering,
(in conjunction with the lime-putty) strongly together, we add an additional
quantity of long fibre, and for this purpose we use old rope or twine cut or chopped
into lengths of from one to two inches and the fibres separated, or, and we have
found the following to be a most excellent fibre for use, old gunny bags, burlaps,
and sacking, the fibre composing these being first cut, torn apart or shredded, and
then reduced by any well known method of pulping into what is known in the
paper trade as "half stock "i.e. a fibrous mass in which the fibres are thoroughly
separated, the fibres being from a half an inch to an inch and a half in length. We
have also found that for the purpose above specified we may use any other form or
forms of fibre such as manilla, hemp, sisal, jute, begasse or cocoanut, it being

page_text: sufficient that the fibre used shall be strong enough to hold the covering mass
firmly together, and that it shall, before mixing with the lime-putty be cut into a
suitable length for the purpose.
We have found that the sponge waste above referred to is especially well adapted
for a body material, and we prefer to use it whenever it can be readily obtained
and it is possible to do so. As will be seen in Figs. 3 and 4, sponge fibre is a very
open, cellular body, and the fibre itself is composed of numerous, small hair like
follicles. This structural formation renders sponge fibre peculiarly valuable as a
body material in a plastic covering, for as the lime putty and lampblack is mixed
with the sponge fibre they enter the cells of the sponge, completely filling them,
while the latter in conjunction with the hair like follicles of the fibre itself enclose
and retain them therein. We have found that a covering formed with sponge fibre
as a filler or body material is much less apt to crumble and disintegrate when in
use than coverings formed with other materials.
When using sponge waste we cut, grind or otherwise separate the sponge clippings
into small pieces, and it is then ready for use. This may be done in a suitable
pulping mill, or in any other preferred way.
The lime-putty and fibre having been thoroughly mixed together, which may be
done by hand or in a mixing mill, in the same manner as ordinary mortar, we then
add to the mass thus formed the oil-lampblack, and proceed to mix the whole
thoroughly and evenly together.
We have found in practice that the preferred proportions of the ingredients by
bulk are about one-third of lime-putty, one-third of oil-lampblack, and one-third
of fibre. Too much lampblack is apt to make the mixture brittle while the more
lampblack used the better non-conductor the covering will be.
When the materials are mixed, the mass thus formed is applied to the boiler,
pipe, or other surface to be covered, in the same manner as plaster is applied to a
wall, with a mason's trowel or some equivalent instrument. We have found in
practice that it is well to have the surface hot when the covering is applied, so that
the covering may dry quickly and be the sooner ready for use.
In cases where very high steam pressures are carried or the surface to be covered
will be subjected to great heat, it is preferred to first apply a priming coat formed
of lime-putty and asbestos fibre, or of other preferred fire-proof materials, and then
apply the non-conducting covering to the exterior of said priming coat. When
this is done it is well to apply the priming coat as a rough coat so that the non-
conducting covering will adhere readily and firmly thereto.
The covering may be applied in any desired thickness; we have found that
when applied to the thickness of from one to two inches it forms an admirable
non-conductor, and gives exceedingly sure and certain results.
It may be applied in one, or several coats or layers, as desired.
After the covering is applied to the surface, especially when such surface is
heated when the application is made, it will speedily dry, and become hard and firm,
and will remain so. When the covering is applied very thickly we prefer to wrap
it with well annealed wire, (No. 19 annealed wire being preferred), as this will
prevent the sagging of the heavy body of covering, and render it solid and
permanent.
In Figure 1 of the drawings the letter A indicates the covering as applied, and
the letter B the boiler shell.
In Figure 2 we have shown a pipe, C, as covered with a sectional
covering, D, D', D³.
For covering small surfaces, such as steam, hot air and hot water pipes the non-
conducting coverings heretofore in use may be grouped in three general classes.
One class includes coverings of a fibrous character, which are applied by wrapping
or winding them about the object to be protected, and are secured in place by cords
or wire, or by a canvas jacket. Another class is composed of those coverings
which are applied in a plastic condition, and are then allowed to set or harden in
position. The third class includes those coverings which are moulded in sections

page_text: like tiles, in shapes conforming substantially to the surface to be protected, and
which, after they have become thoroughly dry and hard, are applied to such
surface, and held in place by wires or bands, or by a canvas or other jacket or
covering.
Coverings of the first class named, of which the common felt covering is an
example, are easily applied and usually may be made to fit snugly against every
part of the surface protected, but they are of more or less open texture, and the
air spaces between the fibres form practically continuous channels through the
body of the felt, from the inner surface to the outer surface, as well as in other
directions, with the result that there is a circulation of heated air through the
covering, and its degree of efficiency is comparatively low. There are also other
objections to coverings of this class, but they need not be enumerated here.
The coverings of the second class, that is, those which are applied in a plastic
condition, may, or may not be exposed to the objection specified above, according
to the nature of their composition, but it is difficult to apply them successfully to
small surfaces such as pipes, and under many conditions it is practically impossible
to so apply them.
In some respects coverings of the third class above referred to are superior to
others. They can be prepared economically; they present a neat appearance
externally; they are effective in preventing direct radiation of heat from the
surface protected, furthermore, they can be applied in places where it would be
practically impossible to apply a plastic compound. The objections to these
moulded sectional coverings, however, as they have been supplied hitherto, are,
that there is no adhesion between the pipes and the coverings, thereby necessitating
the employment of wiring, bands, or wrappings externally, to prevent the sections
from falling from the pipe, and that it is impossible to make these hard sections fit
accurately to the surface of the pipe, so that an air space of greater or less extent
is formed between the pipe and its covering, through which the heated air may
escape through the joints, and at the ends of the sections, thereby defeating partly
the object of the covering.
We have succeeded in producing a sectional covering that is free from the
objections above referred to. By our invention we mould a sectional covering from
a plastic material so as to form a hard exterior layer, which shall be as nearly as
possible a perfect non-conductor, and we provide this outer layer with an inner
cushioning layer, or lining, of material which is sufficiently pliable or yielding to
adapt itself when applied to the pipe C-to any variations in size, and to the
inequalities or irregularities of the surface of the same, thereby completely filling
the space between the pipe and the hard, non-yielding, exterior layer of non-
conducting material.
In the drawing, Figure 2, such hard, exterior, non-conducting layer, is indicated
by the letter and the yielding, or cushioning, lining by .
The relative thickness of the two layers is immaterial, it being only necessary
that the inner cushioning layer shall be of sufficient thickness to fill completely
the space between the pipe, and the hard exterior non-conducting layer, and to
adapt itself to all the inequalities or irregularities of the surface of the pipe.
It should be understood that while we do not confine ourselves to the mixture of
oil-lamphlack, lime-putty and fibre, as above described, as other compounds or
ingredients may be employed to form the exterior non-conducting layer, without
departing from the spirit of our invention, that we prefer to form such outer
non-conducting layer from these materials, as we find that they form a better
non-conductor than others.
Likewise, the exact character of the material or compound which is used for
the cushioning, or inner, part of the covering, is immaterial, so far as the scope of
our invention is concerned, but we have found that a mixture of lime putty and
asbestos is well adapted for the purpose.
In carrying our invention into effect, we mould the outer exterior layer of non-
conducting material into the desired form, which may be done in the same manner

page_text: as tiles or coping, by the use of suitable moulds and mandrels. This is preferably
allowed to indurate and become perfectly hard and firm.
We then mix together substantially equal quantities in bulk of lime-putty and
asbestos, either by hand or by suitable machinery, and then apply the resulting
mixture to the interior of the non-conducting layers already formed, to which it
will adhere. It will usually be found sufficient that the inner cushioning layer be
from one-half to three-quarters of an inch in thickness.
When this mixture has become dried, it will be more or less yielding according
to the amount of asbestos employed, but usually we prefer to soften it still more
with water immediately before it is applied to the pipe. This will cause it to adapt
itself more completely to all the inequalities of the surface to which it is applied,
and at the same time will cause it to adhere strongly to the surface of the pipe, and
as the cushioning layer, in the process of manufacture of the covering section, is
caused to adhere to the inside of the non-conducting layer, the pipe and its covering
will thus be cemented to each other without any air channels or outlets between
them. When the covering sections have been applied to the pipe we unite their
edges by a suitable cement (as a Figure 2), such as lime with an admixture of
fibre, which preferably will contain a non-conducting material, such as lampblack;
or the sections may, if desired, be wrapped with wire, or any other suitable
covering. In order to give a finished appearance to the covering we coat it
exteriorly with a dressing, which is composed of powdered mica in a suitable
vehicle, such as asphalt, which has been cut or dissolved in a sufficient quantity of
naphtha. It should be observed that this outer coating may also be advantageously
applied to the exterior of all forms of plastic coverings.
Our improved sectional coverings, thus made, the sections being united
with a non-conducting cement, and finished exteriorly with the dressing of mica
and asphalt, will be hard and firm; will adhere firmly to the pipe at all places;
will not contain open air channels or passages through which the heat may pass ;
and will be found to answer perfectly all purposes of a non-conducting covering.
In Figure 2 we have illustrated two modes of forming these sections; showing
the lower half of the pipe as covered with a semi-circular section, and the upper
part of the pipe as covered with two quarter sections. It is obvious that the
sections may be made as large or as small as desired, and may be made of any
desired length.
When it is desired to prepare our non-conducting covering in a dry state for
the purposes of transportation, we use a good quality of Portland cement instead
of the lime-putty, and mix the cement, oil-lampblack and fibre together in sub-
stantially the same proportions as hereinbefore given for the lime-putty mixture.
This we prefer to do with a suitable mixing-mill, as the mixing may be more
thoroughly accomplished in this way than by hand. After the material is thus
mixed it may be packed for transportation in barrels, bags or other suitable
packages, and is always ready for use, it being only necessary to add a sufficient
quantity of water to reduce the material to a plastic mass when it will be ready
for application.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. A non-conducting covering composed of a fibrous body material, oil-lampblack
and lime-putty, substantially as described.
2. A non-conducting covering composed of sponge-fibre, oil-lampblack and lime-
putty, substantially as shown and described.
3. A moulded non-conducting covering made in sections, said sections being
composed of an outer layer of hard non-conducting material, and an inner layer of
yielding material, substantially as shown and described.
4. A moulded sectional non-conducting covering constructed substantially as

page_text: shown and described, the sections of which are cemented together about the surface
to be covered.
5. A prepared material for non-conducting coverings consisting of oil-lampblack,
a fibrous body material, and Portland cement, substantially as described.
Dated this 23rd day of May 1893.
FELL & WILDING,
Agents for the Applicant.