Improvements in and relating to Electrical Heaters, Rheostats, and the like, having Comminuted Resistance for the Electric Current.
Year: 1898

page_text: Date of Application, 5th July, 1898-Accepted, 13th Aug., 1898
COMPLETE SPECIFICATION.
Improvements in and relating to Electrical Heaters, Rheostats, and
the like, having Comminuted Resistance for the Electric Current.
I, RICHARD VAN RENSSELAER SILL, residing at No. 106, East 26th Street, in the
City of New York, County of New York, State of New York, United
States of America, Inventor, do hereby declare the nature of my invention, and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
This invention contemplates certain new and useful improvements in electrical-
heaters, rheostats, or the like, having reference to that class employing a com-
minuted resistance in lieu of wires.
Practice has demonstrated that it is highly essential to the successful use of
radiators having comminuted resistance that the latter be uniform throughout,
that is, if the comminuted resistance be more densely packed at one point than
another, the heating of the radiator will lack uniformity, being heated at the
points of least density to a higher degree than at other points where it is tight.
The object of the present invention is therefore to produce an electric heater
or rheostat in which the resistance filling of comminuted material will be of
substantially uniform density throughout its length; which object is attained
by depositing the resistance material in a spiral layer with the convolutions in
contact.
The resistance, which has, preferably, as its essential components, carbon and
soap-stone, is fed into the bore surrounding the feeder, and as the latter is
rotated the compound will pass around its worm or spiral and be deposited at the
lower end thereof in uniform layers. As this deposit occurs the weight of the
feeder serves to make the mass solid throughout its length, its solidity being
uniform at every point. As the bore is thus filled, to near its end, with the
powdered compound, the feeder is removed, a suitable electrode is inserted, the
same preferably consisting of a screw-rod having a nut fitting snug within the bore,
the whole being held by babbitt metal, surrounding the screw-rod.
In the accompanying drawing:-
Figure 1 is a view showing a heater in process of being supplied with its com-
minuted resistance, the mechanism for operating the feeder, as well as the latter,
being shown in elevation, while the heater is in section. Figure 2 is an enlarged
vertical sectional view of the heater, ready for use. Figure 3 is another sectional
view of the heater, taken through one of the bores, showing the feeder in position.
Figure 4 is an enlarged or exaggerated view of a section of the resistance
compound.
Referring to the drawing, A designates a radiator having a longitudinal bore a,
the form shown in Figure 2 being provided with two parallel bores communicating
at one end, as at a', the outer ends of the bores being open. But I do not restrict
myself to any form of radiator, the essential requirement being, however, a
Bylindrical bore.
B is the feeder, which consists of a rod having an upper reduced shank 6 and a

page_text: screw or spiral-like portion 61, the extreme lower edge 62 of which is reduced and
made flat, but is not pointed. The greatest diameter of the screw-portion of the
feeder-rod is about equal to that of the bore of the radiator, so that the spiral
will contact with the interior of the bore. Any suitable means may be employed
for rotating the feeder, and likewise for weighting the same. I have shown a small
wheel 3 on the upper end of the feeder-rod over which is passed a weighted rope b*.
As the feeder-rod is rotated, and the resistance compound is inserted in the open
end of the bore, it will pass down around the spiral and be deposited in the bore
in thin layers, one upon the other, but all thoroughly packed together by reason
of the weight of the feeder. As each bore is filled to near its open end, the feeder
is removed and a threaded rod C is inserted. On this rod is a nut d which
practically corresponds to the diameter of the bore, forming a stop for babbitt
métal, as at d¹, by which the ends of the bores are hermetically closed.
Thus, it will be seen that the comminuted resistance is so packed within the
radiator in spiral form with contacting convolutions, that it presents a uniform
density throughout its entire length or depth, the compound being deposited in
equal layers as the feeder is rotated and rises upon its own deposit. In this way
the danger of obtaining an unequal heat at any point is successfully avoided.
The advantages of my invention will be at once apparent to those skilled in
the art, but may be briefly stated as follows:-First, the resistance being equal
at all points, there will be no heating in spots, thereby avoiding cracking and
breaking of the shell or tube due to unequal expansion or contraction. Second,
owing to the convoluted or spiral form of the resistance material, there can be
no transverse fracture thereof by expansion and contraction, since even though
two convolutions should partially separate during contraction, the continuity of
the spiral will remain unbroken and the passage of the current permitted.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:
1. An electric heater or rheostat consisting of an outer shell, and a resistance
filling therein in the form of a spiral layer of comminuted material with the con-
volutions in contact, substantially as set forth.
2. An electric heater or rheostat consisting of an outer shell, a densely packed
resistance filling therein in the form of a spiral layer of even thickness with the
convolutions in contact, and electrodes in the ends of the shell, substantially as
set forth.
Furth day of July 1898.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.