Improvements in or relating to Electric Resistance Devices, also applicable for Measuring Electric Currents.
Year: 1891

page_text: Date of Application, 8th May, 1891
Complete Specification Left, 8th Feb., 1892-Accepted, 12th Mar., 1892
PROVISIONAL SPECIFICATION.
Improvements in or relating to Electric Resistance Devices, also
applicable for Measuring Electric Currents.
I, CHARLES WALTER Cox of 8, Strand Street, Liverpool in the County of
Lancaster, Electrician, do hereby declare the nature of this invention to be as
follows:-
This invention relates to certain improvements in or in connection with electric
resistances. The invention is also applicable for measuring electric currents.
In carrying the invention into effect I make the resistance device in the
form of a tube which may be of any suitable material, such as platinoid, German
silver or iron.
This tubular resistance may be fixed or coiled in any desired manner, and
mounted on an insulated base plate or frame, having connections for the purpose of
leading away any current flowing in the resistance, at predetermined points in the
length of the resistance tube.
On one or both ends of the resistance there is attached a piece or pieces of tube
having approximately the same diameter as the resistance tube, but made of an
insulating material such as indiarubber or glass.
One or both of these insulating tubes is or are then placed in connection
with a tank or other water supply, the said tank or supply being placed in such a
manner and at such a height above the resistance tube that the water can
circulate throughout the whole length of the resistance tube. The objects of this
circulation of water are as follows:-
1st. To keep the temperature of the resistance device practically constant during
the passage of varying currents of electricity.
2nd. To enable a very heavy current to be passed through a relatively small
resistance coil without great heat being developed.
3rd. To afford perfect security from fire when heavy currents are used.
The electric currents may also be measured by placing a thermometer in the
water tank and noting the rise of temperature.
When the two ends of the coil are connected to the water supply, circulation
proceeds in the ordinary manner as the temperature of the coil rises. Under these
circumstances the temperature of the tube and also the reservoir would be in pro-
portion to the current of electricity flowing, due account being taken of radiation
and external cooling influences.
When the upper end of the tube alone is connected to the water supply,
the lower end is left open, or partly open by means of a tap or other regu-
lating device, so enabling the water to simply flow through the whole length
of the tube in sufficient quantity to keep the coil cool, no matter what the current
may be.
The total resistance of the metallic part of the coil will be lowered by the
total resistance of the shunt path formed by the water throughout the system.
This shunt path, being proportionately of very great resistance to the metallic path
offered, may in most cases be ignored, although of course the joint resistance cau
be easily measured.
M 1901
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in or relating to Electric Resistance Devices, also
applicable for Measuring Electric Currents,
I, CHARLES WALTER Cox of 8 Strand Street, Liverpool in the County of
Lancaster, Electrical 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 :-
This invention relates to certain improvements in or in connection with electric
resistances. The invention is also applicable for measuring electric currents.
In carrying the invention into effect, I make the resistance device in the form
of a tube which may be of any suitable material, such as platinoid, German silver
or iron.
This tubular resistance may be fixed or coiled in any desired manner, and mounted
on an insulated base plate or frame, having connections for the purpose of leading
away any current flowing in the resistance, at predetermined points in the length
of the resistance tube.
On one or both ends of the resistance there is attached a piece or pieces of tube
having approximately the same diameter as the resistance tube, but made of an
insulating material such as india rubber or glass.
One or both of these insulating tubes is or are then placed in connection with a
tank or other water supply, the said tank or supply being placed in such a manner
and at such a height above the resistance tube that the water can circulate
throughout the whole length of the resistance tube. The objects of this circula-
tion of water are as follows-
1st. To keep the temperature of the resistance device practically constant during
the passage of varying currents of electricity.
2nd. To enable a very heavy current to be passed through a relatively small
resistance coil without great heat being developed.
3rd. To afford perfect security from fire when heavy currents are used.
The electric currents may also, be measured by placing a thermometer in the
water tank and noting the rise of temperature.
In the accompanying drawing a tubular resistance device is there shown of a
total resistance of 100 of an ohm, divided into tenths, each having a resistance of
To ohm. A less or greater number of coils may of course be used if desired.
In the drawings, A are the resistance tubes containing the water or other cooling
liquid, B connecting tubes for joining together the tubes A, and preferably of
larger section than said tubes. C are copper or brass blocks for connection to
mains, to which said end tubes B are fastened. The object of this arrangement is
that these end pieces of tube, together with the blocks, shall have a resistance so
low in comparison to the resistance tube proper as to be negligible. D are the
insulating pipes of rubber or glass for conveying the cooling liquid to the resist-
ance. E are terminals connected to the end blocks C for leading off the current
at predetermined points in the resistance.
When the two ends of the coil are connected to the water supply, as shown,
circulation proceeds in the ordinary manner as the temperature of the coil rises.
Under these circumstances, the temperature of the tube and also the reservoir would
be in proportion to the current of electricity flowing, due account being taken of
radiation and external cooling influences.
When the upper end of the tube alone is connected to the water supply,
the lower end is left open, or partly open, by means of a tap or other regu-
lating device, so enabling the water to simply flow through the whole length
of the tube in sufficient quantity to keep the coil cool, no matter what the
current may be, or the heat of the water may be utilised by allowing the water,
after being heated by the resistance, to be used for boilers or other useful
purposes.

page_text: The total resistance of the metallic part of the coil will be lowered by the total
resistance of the shunt path formed by the water throughout the system. This
shunt path, being proportionately of very great resistance to the metallic path
offered, may, in most cases, be ignored, although, of course, the joint resistance can
be easily measured.
I am aware that water has been used as well as other fluids as a resistance inside
tubes, but the latter have always been of glass or some insulating material, and the
water or fluid has been the only path for the current, but, in my invention, the
water conveys only a fraction of the total current flowing and its function is there-
fore limited to cooling the resistance proper.
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. The improvement in electrical resistance devices, which consists in forming
them of a tubular resistance coil of platinoid, German silver, iron or the like,
through the whole length of which water from a water tank or other source of
supply is adapted to circulate, substantially as described, said water conveying
only a fraction of the total current flowing, its function being limited to keeping
the resistance coil cool.
2. The general combined arrangement and construction of parts forming the
improved electric resistance device, substantially as described.
Dated this 6th day of February 1892.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Nottingham, and London, Patent Agents.