Wicks, and the Process of Making the same.
Year: 1897

page_text: Date of Application, 13th May, 1897-Accepted, 13th May, 1898
COMPLETE SPECIFICATION.
Lamp Wicks, and the Process of Making the same.
I, CHARLES LANCASTER MARSHALL, a citizen of the United States, residing at
Cedar Grove, in the County of Essex and State of New Jersey, Manufacturer, 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 follow-
ing statement:
-
My invention relates to improvements in wicks for use in lamps, oil stoves and
heaters designed for burning animal and vegetable oils, kerosene, petroleum, or
other suitable hydro-carbons either for heating or lighting purposes; and to the
improvements in the methods for making such wicks. The wicks may also be
adapted for use in candles of wax paraffine or other suitable materials.
The object of my invention is to produce a fibrous carbon wick of superior
capillary properties and odorless combustion of the oil; together with the quality
of being a non-conductor of heat and slow combustibility of the materials of the
wick; and in carbonizing by a distilling process to such an extent as to retain
the flexibility of the ordinary wick of commerce, together with sufficient strength
and durability to permit the use of the carbonized wick in all classes of burners.
I accomplish this object by a method of distillation and carbonization which
results in the removal from the wick of the oily oleaginous and gummy substances
therein contained, and in a uniform carbonization of the material of which the
wick is chiefly composed. To maintain sufficient strength in the wick when
weakened by considerable carbonization I may also use in the texture some
material, which, when subjected to the said distillation and carbonization or any
other similar weakening process, will not be so affected that it loses its textile
strength. Or I may attain this latter object by combining with the lamp wick
material, which has been subjected to the ameliorative though weakening process,
new material which has not been so treated. In other words I aim to produce a
wick which is first distilled and deprived of water, dirt, oily substances &c.;
second partially carbonized; and third, strengthened for hardest useage. I would
have it understood however that distillation alone which drives off impurities is in
itself a most valuable feature of the invention; also partial carbonization in a
closed oven; also the strengthening of a wick which has been weakened by some
such process. It is my intention to cover these features in this patent.
In the drawings, Figure 1 shows a wick.
Figure 2 shows a pack of wicks ready for the process of distillation and
carbonization.
Figure 3 shows the apparatus by means of which my treatment may be effected.
In Figure 1, 1 is the warp and 2 is the weft. The weft is preferably composed of
two sets of fibres, asbestos fibres 3, and cotton or other fibres 4. I prefer the weave
ordinarily found in cotton wicks though any weave may be used. Wicks may be
woven of previously prepared fibres, or they may be woven first and prepared
afterwards. In fact I find it desirable to use the ordinary wicks of commerce and
by suitable subsequent treatment produce my new and improved article.

page_text: My wick differs from those heretofore invented in several respects. First, it is
deprived of oleaginous and gummy matters. If wicks are subjected to a heat in
an oven to four or five hundred degrees Fahrenheit, a vapor of certain liquids,
oleaginous and gummy matters is formed. If the oven is again cooled, these
vapors are again absorbed by the wicks. The wicks suffer by this treatment for
their capillary powers are reduced. This is an incident to the complete carboniza-
tion of wicks in a sealed oven. A wicks subjected to this process retains its
gummy and oleaginous products, while my wick is deprived of them. So that
even without carbonization my wick is superior to those heretofore proposed in its
capillary powers.
Wicks have been washed with acids to remove these oleaginous matters, but such
treatment rots the fibres and destroys them for lamp use.
matters by heat does not injure the fibres seriously.
The removal of these
The complete carbonization of wicks has been attempted, but the fibres become
brittle, and the web drops to pieces. Partial carbonization does not make the
fibres brittle and does not impair the strength necessary to a wick for use in
lamps and stoves. Yet I may add a very small percentage of asbestos to the
weft for reinforcement when the product is weakened by a too severe process. I
have added this to the weft for two reasons: First, it is the weft on
which a ratchet chiefly works; and second, it is the warp on which the
capillary powers of a wick chiefly depend, and hence the warp though it may
contain strengthened material is better untouched. Wicks of pure asbestos have
been proposed but Tack capillary powers.
Some wicks have been dipped into powdered carbon suspended in liquid. This
treatment closes the pores of the wick, seriously retarding their capillary properties.
Other wicks have been made of block carbon, but, owing to their rigidity and lack
of capillarity, have been found useless for lamp trade. It is by partially carboniz-
ing the fibres themselves, not enough to lose materially the textile strength of the
fibre and yet enough to give sufficient carbon to whiten the flame, that I have been
able to produce a wick of use to the trade.
It is obvious that the partial carbonization of my wick may be used without the
removal of the oleaginous matters, and the wick still be superior to those used in
the trade. And it is also obvious that the removal of the oleaginous matters
without the partial carbonization will produce a wick having greater capillary
properties than the present wicks of commerce. And it is my intention to cover
such products in this patent.
The method and apparatus which I employ in producing my wick are simple
and inexpensive. In Figure 3 is shown one form of apparatus which may be used.
An inner casing 5 made of wire netting or of perforated sheet metal is provided
with an open end 6, having flared edges 7. The wicks are packed closely in this
casing, and the casing should have therefore the same length and breadth as the
wicks. This inner casing 5 is put in.an-oven-8 having an open end 9 with edges 10
-to-fit against the flared edges 7 of the inner casing. Raised metal portions 11
inside the oven prevent any contact between its walls and the casing, thus pro-
viding for the free expulsion of the vapors.
The cover 12 slips over the open end 9 of the oven. This cover is provided
with the vent 13, adapted to be closed by a sliding valve 14, mounted in staples 15.
This valve 14 has an opening 16. When the valve is raised, the hole registers
with the vent 13, and when down, the vent is closed.
Figure 2 shows a pack of wicks ready for the oven. They are placed in the
casing 5, the casing is put into the oven 8, the cover 12 is put on, the valve 14
raised to its upper position, and the apparatus put into the furnace oven.
The temperature of the oven is then slowly raised. When it reaches about
200 to 250 degrees Fahrenheit, the water in the wicks is converted into steam,
which loosens the fibres of the entire mass of the body of the wicks.
At about the same time the lighter solvents or oleaginous substances in the
.

page_text: wicks are volatilized and the vapors pass out from the wicks into the space between
the inner casing and the oven or box in which it is placed.'
As the pressure increases the excess gases are forced through the open vent 13
into the outer oven and from there escape through dampers.
As the heat increases the heavy and more solid oleaginous substances are
volatilized' and, by the time the temperature reaches about 450 or 500 degrees,
these matters are driven out of the vent in the form of vapor or gas.
After all the gases have escaped, I close the sliding valve and continue to raise
the temperature until it reaches about 700 or 800 degrees Fahrenheit, or I may
leave the temperature at 400 or 500 degrees a number of hours. The wicks then
assume an even color of brown and the fibres have a silken appearance. The
hirsute projections of the fibres are not injured and their capillary powers "äre
retained.
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The furnace oven is now, opened and the inner, oven containing the, wicks is
cooled off. When their temperature is sufficiently low to prevent combustion in
the air, the wicks are taken out and are ready for use.
The advantages of this process over others are that a large number of wicks
may be treated at one time and in an inexpensive manner, with absolute safety
from loss or damage by ignition.
The vapors or gases improve the condition of the wick in its capillary properties,
probably on account of the swelling and purification of the fibres. This process
gives another peculiar property-that of being receptive to oils for burning, but
unreceptive to water, or some other liquids that will not burn. So that if a lamp
is filled partly with water and partly with oil, the oil only will be carried to the
flame. This renders the wicks valuable for lamps used on railroads. Railroad
lamps are subjected to all kinds of weather and their light is often extinguished
by rain water reaching the wick, and being carried to the flame. My wick prevents
any such occurrence as it will not absorb water.
Again there is no loss from lateral shrinkage, and only a trifling loss from
longitudinal shrinkage. When cylindrical wicks are used this is of particular
value, as shrinkage would render them incapable of being used with the lamp for
which they were made. Complete carbonization causes great lateral shrinkage
as well as longitudinal loss.
The method of packing the wicks one above the other in a solid and compact
mass prevents lateral distortion and maintains an evenness that could not be
obtained if the wicks were loosely thrown into the oven or distributed singly over
a tray.
Although 25% of the original weight of the wicks can be removed by the
process, yet the fibres of the wicks retain their full size and are perhaps even
enlarged. This is of the greatest value for increasing the capillary powers of the
wicks.
Wicks prepared by my process will hold in capillary suspension five times their
own weight of oil while the same wicks before being treated hold in suspension
only three times their own weight of oil.
The carbonization of the wick assists the consumption of oxygen, giving greater
heat thus rendering the flame whiter. The greater ease with which the flame
consumes carbon renders it less liable to smoke.
My wick may be used without any reinforcement as described above, yet I
prefer when the carbonization is considerable to avoid any possibility of weakness
by using a very small per cent. of asbestos in the weft, and I do claim this additional
mode of strengthening as a part of my invention. The asbestos may be woven
in with the weft, or it may be stitched along it after the wick is prepared.
In preparing wicks for candles I proceed in the manner described except that I
make them very small and often with hollow centers in order that they may be
consumed as rapidly as the body of the candle. It is obvious that no reinforce-
ment is needed here.
Wicks have heretofore been made of asbestos, but the low capillary properties

page_text: of asbestos render such wicks valueless. My wick uses the smallest possible amount
of asbestos compatible with the requisite strength.
Thus my invention contains three features: First the cleansing by distillation
of water, oils, gummy substances, and other impurities; second, partial carboniza-
tion by heat in the absence of oxygen; third, strengthening the texture when it
is too highly carbonized. These features are intended to be covered by this patent,
singly or in combination as set forth in the appended claims.
Cotton wicks contain from five to eight per cent. of water. My distillation
process drives off all water, and leaves wicks in a dry condition. They always
remain so. They are not affected by surrounding atmosphere as cotton wicks are.
The longer my wicks are kept the better they become.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed I declare that what I
claim is:-
1. A wick for lamps having fibres partially carbonized and devoid of oleaginous
substances.
2. The method of treating wicks which consists in driving off by the application
of heat and permanently separating the oleaginous or gummy substances from said
wicks.
3. The method of treating wicks which consists in raising said wicks to a
temperature sufficient to partially carbonize their fibres in a chamber substantially
free from oxygen.
4. The method of treating wicks which consists in raising them to a tempera-
ture adapted to vaporize oleaginous and gummy matters in a receptacle having an
escape vent, and then subjecting said wicks to a partially carbonizing temperature.
5. The method of treating lamp wicks which consists in packing them close in
a receptacle, shutting off access of oxygen and raising them to a partially carboniz-
ing temperature.
6. The method of treating wicks which consists of packing them closely in a
receptacle, driving out the vapor through an escape vent by heat, and raising them
to a partially carbonizing temperature.
7. In a partially carbonized lamp-wick, a warp and weft of carbonized material,
and asbestos fibres twisted about the strands of said weft for reinforcement.
8. As an article of manufacture, a lamp-wick, said wick composed of partially
carbonized fibres, and asbestos fibres combined with said partially carbonized
fibres for purposes of reinforcement.
9. As an article of manufacture, a lamp-wick, composed of carbonized fibres,
and reinforced by asbestos or other material of a refractory nature.
10. As an article of manufacture, a lamp-wick, composed of carbonized fibres,
and reinforced by fibres of an uncarbonized material.
11. In a lamp-wick, the combination of fibres which have been subjected to a
carbonization or other weakening though ameliorative process, and additional
fibres of a material not so subjected.
12. In a lamp-wick, the combination of fibres which have been subjected to a
carbonization or other weakening though ameliorative process, and additional fibres
not susceptible to such a process.
Dated lot dar of No 1807