Year: 1897

page_text: Date of Application, 2nd Dec., 1897
Complete Specification Left, 1st Oct., 1898-Accepted, 12th Nov., 1898
I, WALTER ROWBOTHAM, Engineer, of 24, Harleyford Road, Vauxhall, in the County
of Surrey, do hereby declare the nature of this invention to be as follows:-
My invention relates to variable liquid resistances for governing electrical circuits
of any kind, and methods for automatically varying these resistances.
My invention consists in arranging a large number of plates in parallel in a
vessel, and in causing the resistance of this cell to be varied by altering the level
of the liquid in the vessel, or by altering the resistance of the liquid by varying the
strength of the solution.
In carrying my invention into effect according to oue modification, I use a vessel
containing a large number of plates connected in parallel, and connected with one
terminal of the resistance or resistance cell. Another set of plates also connected
in parallel, and interleaved between the first set, are connected with the other
terminal of the cell. This vessel or cell I provide with an inlet pipe and an outlet
pipe, each being controlled by a cock or valve. I operate one or both of these cocks
or valves from a shunt wound, solenoid, whose terminals are connected across the
circuit to be governed so that a fall in potential will cause the plunger of the solenoid
to be moved, and to therefore open the supply valve of the resistance cell, thus
raising the level of the liquid and decreasing its resistance, and therefore tending
to restore the current to its original value. On the other hand in a similar manner
a rise in the potential will shut the supply valve and if necessary open the outlet
valve, thus increasing the resistance of the cell.
I may use an ordinary vessel controlled by a ball cock from a cistern containing
the solution, which must be of sufficient strength to make the liquid conducting.
The plates should be of material not acted on by the liquid, and they may be arranged
either vertically or horizontally in the containing vessel.
According to another modification of my invention, I may, if necessary, provide
for further range of variation by controlling the strength of the solution in the
resistance cell. This I may do by having a supply tank of strong solution, and
operating its cock or valve automatically ns before to supply the cell. I may pro-
vide an arrangement whereby when the level of the liquid in the cell reaches a cerinin
height, it operates a float, and by means of this float short circuits the cell, thus
cutting out the resistance. It will be obvious that two solenoids may be employed
with suitable windings for controlling the level of the liquid in the resistance cell.
MARKS & CLERK,
18, Southamptou Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents.

page_text: Improvements in Variable Electrical Resistances.
I, WALTER ROWBOTHAM, of 24, Harleyford Road, Vauxhall, in the County of Surrey,
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 :-
My invention relates to variable liquid resistances for governing electrical circuits
of any kind and methods for automatically varying these resistances.
My invention consists in arranging a large number of plates in parallel in a vessel,
and in causing the resistance of this cell to be varied by altering the level of the
liquid in the vessel or by altering the resistance of the liquid by varying the strength
of the solution.
Several modifications of the invention are illustrated in the accompanying sheets
of drawings as follows:-
Figure 1 is a diagraminatic sectional elevation of an improved resistance cell with
the plates vertical and with a shunt solenoid automatically governing the resistance.
Figure 2 is a diagrammatic sectional elevation of a cell and reservoir with the
plates horizontal in the vessel.
Figure 3 is a diagrammatic side elevation of an automatic short circuiting device
arranged on the improved resistance cell.
8
In carrying my invention into effect as illustrated in Figure 1 of the drawings I
use a vessel A containing a large number of plates BB connected in parallel, and
connected with one terminal C of the resistance or resistance cell. Another set of
plates D D also connected in parallel, and interleaved between the first set BB are
connected with the other terininal E of the cell. This vessel or cell A, I provide
with an inlet pipe F and an outlet pipe G, each of these pipes being controlled by
valves lettered respectively II and I. I operate both valves H, I, from a shunt wound
solenoid whose terminals are connected across the circuit K to be governed (as
indicated diagrammatically) so that a fall in potential will cause the plunger L of the
solenoid to be moved and therefore to open the supply valve H of the resistance
cell and raise the level of the liquid thus decreasing its resistance and therefore
tending to restore the current to its original value. On the other hand in a similar
manner a rise in the potential will operate the solenoid L in the reverse direction
and shut the supply valve H a further movement being necessary to open the outlet
valve thus increasing the resistance of the cell.
The precise operation of the device shown in Figure 1 of the drawings is as
follows: A spring O tends to pull the solenoid plunger L in an upward direction
while the solenoid J itself tends to pull it in a downward direction. The pivotted
quadmaut M operates upon the vertical rack N held in suitable guides and this rack
bas, as shown, two turned over jaws which act upon collars fixed on the ends of the
valve spindles H and I. A sufficient lead is given to one or other of the collars so
that one valve must always be closed before the other opens. It is evident that the
potential of the current altering will cause the plunger 1 of the solenoid to move in
one or other direction and thus close or open the valves H or I in the manner herein-
before described. I do not limit myself to the precise mechanical arrangement
shown on Figure 1 of the drawings to effect the opening and shutting of the supply
and outlet valves H and I as any other equivalent arrangement in which a shunt
wound solenoid is the governing element may be employed.
The construction shown in Figure 2 of the drawings illustrates the modification
necessary when the plates are arranged horizontally similar letters in this view
indicate similar parts to those in the modification hereinbefore described. The
plates Bare connected to a terminal C and the plates D are connected to a terminal E.

page_text: In this arrangement a reservoir P contains the solution forming the liquid resistance
and the level of this reservoir is controlled by an ordinary ball cock Q, the valves or
cocks R and S forming respectively the inlet and outlet for the solution may be
controlled by a shunt wound solenoid connected across the circuit to be governed.
It is evident that as the liquid forming the resistance is admitted to the cell the
plates become submerged in successive pairs and not as in the previous modification
all gradually submerged.
According to another modification of my invention as illustrated in Figure 3 of
the drawings I may provide an arrangement whereby when the level of the liquid in
the resistance cell A reaches a certain height, such as say a b, it operates on a float T
and cuts out the resistance cell in the following manner. This float lifts a contact U
so that it makes connection with a second contact V then the main circuit K instead
of passing through the resistance cell as shown in the drawing is short circuited
through W X thus cutting ont the resistance.
According to another modification of my invention I may if necessary provide for
a further range of variation by controlling the strength of the solution in the
resistance cell. This I may do by having a supply tank of strong solution and
operating this cock or vaive automatically as before to supply the said cell. It will
be obvious that in controlling the cocks or valves by solenoids more than one solenoid
with suitable windings may be employed and without departing from the subject of
the present invention.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be perforined I declare that what I
claim is :-
1. A variable electrical resistance placed in a main circuit consisting of a cell
containing liquid and provided with two sets of plates so arranged that each set is
connected in parallel to a terminal and interleaves with the other set and further
controlling the level of the liquid by a shunt wound solenoid connected across the
main circuit operating the inlet and outlet valves or cocks as the potential of the
current rises or falls.
2. In variable electrical resistances where the resistance is altered by the rise or
fall of a liquid in a cell consisting of two sets of interleaved plates connected
respectively in parallel to two terminals, arranging the plates horizontally within the
cell so that each plate or pair of plates is successively submerged or uncovered by
the liquid substantially as herein before described.
3. In variable electrical resistances where the resistance is altered by the rise or
fall of a liquid in a cell consisting of two sets of interleaved plates counected
respectively in parallel to two terminals arranging a cut out float in such a manner
that when a predetermined level of liquid is exceeded in the cell the current is short
circuited and the resistance cell thrown out of action substantially as described.
Dated this
US IRL XVI URCKOO
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents.
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents.