IMPROVE- MENTS IN THERMO-ELECTRIC BATTERIES
Year: 1877

page_text: LETTERS PATENT to Cecil Wray and Loonard Wray, junior, both of Waltham-
stow, in the County of Essex, Gentlemen, for the Invention of "IMPROVE-
MENTS IN THERMO-ELECTRIC BATTERIES."
Scaled the 5th June 1877, and dated the 6th March 1877.
PROVISIONAL SPECIFICATION left by the said Cecil Wray and Leonard
Wray at the Office of the Commissioners of Patents on the 6th March 1877.
CECIL WRAY and LEONARD WRAY, junior, both of Walthamstow, in the County
of Essex, Gentleman. "IMPROVEMENTS IN THERMO-ELECTRIC BATTERIES."
This Invention relates to certain improvements upon an Invention for which we
obtained Letters Patent dated the 6th of March 1876, No. 976.
The first improvement relates to a new alloy for the construction of the thermo-
electric bars, for the purpose of increasing their hardness, strength, and infusibility..
The second improvement relates to the mode of casting the thermo-electric bars
so as to ensure their being free from cracks, and of forming the moulds in which
the bars are be cast.
The third improvement relates to the manner in which these bars are built up
into piles, so that they are completely protected from external injuries.
The metals and alloys usually employed for forming the negative bars are very
fusible and extremely brittle, and very few indeed of these bars are obtained free
from extremely minute cracks which speedily become enlarged and cause the ruin of
the bars.
It has been proved that when the bars are made of antimony and zinc alloy alone,
and cast in even very highly heated metal moulds, scarcely any are free from these
almost invisible cracks.
It has also been found that when (as by the usual mode of building up the bars
or layers of bars into what constitutes the pile itself), from one-half to two-thirds
of the whole length of the bars is left exposed (ostensibly for the purposes of
radiation), the bars are exposed to the almost certain danger of external injury,
and even to the liability to fracture from any very slight jar in moving the pile
about.
In carrying out the first part of our Invention we employ a new alloy consisting
of antimony, zinc, and iron (for making the bars), the definite proportion of the
latter being materially dependent upon the special purpose for which the pile is
intended, but the proportion may be stated generally at from one to five per cent. of

page_text: iron (cast iron by preference) in a finely divided state. The iron when incorporated
in this form with the other metals greatly increases the strength, hardness, and
infusibility of the bars.
The second part of the Invention consists in the use of moulds made or built up
of pieces of earthenware, clay, or other analogous substance, so as to form moulds
of the proper shape for casting the thermo-electric bars in. The pieces of which
these non-metallic moulds are constructed are by preference embedded in sand and
loam, and by this means we are enabled to obtain the thermo-electric bars perfectly
free from cracks.
In constructing or building up the piles of these thermo-electric bars, we entirely
enclose or embed (throughout their whole length) each and all of the bars in clay or
other suitable substance, so that only the connections at the outer ends are in any
way exposed. When so building up the piles we prefer to employ (in combination
with this thorough encasement of the bars) the insulating discs, plates, or frames,
provided with supporting blocks (as set forth and claimed in the Specification of
our said Patent, No. 976, of 1876, above referred to), but we do not confine ourselves
to this combination.
By this improved mode of building up our piles, the bars are not only protected
from external dangers, but they heat and cool down more gradually, and their
practical durability and efficienco are thereby greatly prolonged.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said Cecil Wray and Leonard Wray in the Great Seal Patent Office on the
5th September 1877.
CECIL WRAY and LEONARD WRAY, junior, both of Walthamstow, in the County
of Essex, Gentlemen. "IMPROVEMENTS IN THERMO-ELECTRIC BATTERIES."
This Invention relates to certain improvements upon an Invention for which we
obtained Letters Patent, dated the sixth March, One thousand eight hundred and
seventy-six, No. 976.
The first improvement relates to the employment of a new alloy for the construction
of the thermo-electric bars, the object of the use of the new alloy being to increase the
hardness, strength, and infusibility of the thermo-electric bars.
The second improvement relates to the mode of casting the thermo-electric bars so
as to ensure their being free from cracks, and to this end the moulds in which the
bars are to be cast are constructed in a peculiar manner, as will be hereafter
explained.
The third improvement relates to the manner in which these bars are built up
into piles, the object of this improvement being to completely protect them from
external injuries.
The metals and alloys usually employed for forming the negative bars are very
fusible and extremely brittle, and very few indeed of these bars are obtained free
from extremely ininute cracks, which speedily become enlarged and cause the
destruction of the bars.
It has been found that when the bars are made of an alloy of antimony and zinc
alone, and cast in even very bighly heated metal moulds, scarcely any of the bars are
free from the almost invisible cracks above mentioned.
It has also been found that when building up the bars or layers of bars in
the usual way into what constitutes the pile itself, from one-half to two-thirds
of the whole length of the bars is left exposed (ostensibly for the purposes of
radiation), and the bars thus exposed are liable to the almost certain danger of
external injury, and even to fracture from any very slight jar in moving the pile
about.
In carrying out the first part of our Invention we employ a new alloy consisting
of antimony, zinc, and iron, for making the bars, the definite proportion of the latter

page_text: metal being materially dependent upon tho special purpose for which the pilo is
intended, but the proportion may be stated generally at from one to five per cent. of
iron (cast iron by preference) in a finely divided state. The iron when incorporated
in this form with the other metals greatly increases the strength, hardness, and
infusibility of the bars. The proportions of antimony and zinc are the same as
those usually employed for these bars. The present improvement therefore consists
substantially in the addition of iron in a finely divided state to the brittle metals
usually employed in forming the thermo-electric bars.
The second part of the Invention consists in the use of moulds made or built up
of pieces of earthenware, clay, or other analogous substance, so as to form moulds of
the proper shape for casting the thermo-electric bars in. The pieces of which these
non-metallic moulds are constructed are by preference embedded in sand or loam,
and by this means we are enabled to obtain the thermo-electric bars perfectly free
from cracks or flaws.
In constructing or building up the piles of these thermo-electric bars wo entirely
enclose or embed throughout their whole length cach and all of the bars in clay or
other suitable substance, so that only the connections at the outer ends of the bars
are in any way exposed. We have found by experience that when the bars do not
exceed two inches in length there is no practical advantage in embedding them
throughout their whole length in the clay; we do not therefore intend to adapt
our Invention to piles made of such small bars; when however the bars are threo
inches or upwards in length our improved mode of constructing the piles will be
found very useful; or if preferred we encloso or embed the inner ends only of each
bar in clay for the distance, say, of one inch, and we enclose the remaining portion
of each bar in a mixture of clay and paper pulp, which being lighter than clay alone
has its advantages. When so building up the piles wo prefer to employ in com-
bination with this thorough encasement of the bars, the insulating discs, plates, or
frames, provided with supporting blocks (as set forth and claimed in the Specifi-
cation of our said Patent, No. 976, of One thousand eight hundred and seventy-six,
above referred to), but we do not confine ourselves to this combination, as by solidly
filling in between the bars with clay or other suitable substance, as above mentioned,
a good deal of the superincumbent weight will be taken off the bars.
By this improved mode of building up our piles, the bars moreover are not only
protected from external damage, but they heat and cool down more gradually, and
their practical durability and efficiency are thereby greatly prolonged.
In the accompanying Drawing Fig. 1 is a plan view of the lower half of a mould
constructed according to our Invention for casting the thermo-electric bars, the
upper half of the mould or flask having been removed in order that the interior of
the lower half may be more clearly seen; Fig. 2 is a longitudinal vertical section (taken
in the line 1, 2, of Fig. 1) of the mould, complete, showing the upper half in place,
and the gates or passages through which the molten metal is poured into the mould.
The lower half of the cast-iron flask is seen at a, a, and the upper half at a¹, a', the
only difference between these parts and the ordinary cast-iron flasks for casting
metals being that the upper half a', a', is made much deeper than usual, in order
that the vertical passages or gates b, b, for conducting the molten metal to the
spaces c, c, of the moulds may be lengthened so as to give a head of metal, in order
to increase the pressure in the moulds, so as to make sound castings. It will be
seen that the open spaces or moulds c, c, for casting the thermo-electric bars
are formed by placing a number of solid pieces d, d, made of earthenware, clay,
or other analogous substance which is capable of resisting the heat of the red hot
molten metal or alloy of which the thermo-electric bars are composed. These pieces
are moulded of the proper form, and then dried and baked in a kiln, and are
placed on a smooth flat earthenware plate a*, a*, which forms the bottom of the
mould.
We do not limit ourselves to the precise form or shape of these pieces d, d, but
we have found by experience that the form shown in the plan view, Fig. 1, gives a

page_text: satisfactory result, as it admits of the metallic alloy expanding in setting without
displacing the non-metallic picces d, d, of which the moulds are composed.
We would here remark that if precautions were not taken to allow for this
expansion of the alloy, either the moulds would be fractured during the setting
process, or the bars would become so fixed in the mould that they would with
difficulty be removed therefrom. The thermo-electric bars cast in the spaces c, c, of
the mould are electro-negative, and the ends of the electro-positive picces e, c, are
inserted in the moulds before the molten inetal is poured therein, and consequently
these ends are embedded in the body of the bar, as shown in the Specification of our
former Patent.
In order to enable the ends of the positive bars e, e, to be embedded in the
negative bars, the wooden or other pieces used as cores to separate the earthenware
pieces d, d, are made hollow, as shown in cross section at Fig. 3, so as to enclose the
ends of the positive bars, while the mould is being made up. When this operation
has been completed the cores are removed, and the projecting ends of the positive
bars will project into the spaces left.
When the earthenware blocks d, d, are arranged in place in the bottom flask,
with the wooden or other pattern pieces between them to form the spaces c, c, the
vacant space behind the earthenware blocks is filled in with sand well rammed
in. The upper flask is then placed on the top of the lower one, and suitable
cores for forming the gates or passages, for the flow of the molten metal, having
been properly arranged, the upper flask is filled with sand in the usual manner,
and when the cores are withdrawn the casting may be carried on in the usual
manner.
It will be understood that as the earthenware pieces d, d, are bad conductors of
heat the thermo-electric bars will be allowed to cool more gradually than if metal
moulds were employed as heretofore, and consequently there is less liability to
produce defective bars or bars with flaws or small cracks in them.
Having now described our Invention of " Improvements in Thermo-electric
Batteries," and having explained the manner of carrying the same into effect, I claim
'as the Invention secured to us by Letters Patent as aforesaid,-
First. Constructing the thermo-electric bars of an alloy of antimony, zinc, and
iron, as and for the purpose herein set forth.
Second. Constructing the moulds (for casting the thermo-electric bars) of pieces
of earthenware, clay, or other analogous substance, as and for the purpose herein set
forth.
Third. Constructing or building up the piles of thermo-electric bars by enclosing
or embedding them throughout their whole length in clay or other suitable substance,
'so that the pile will consist of one solid mass, as and for the purposes herein set
forth.
In witness whereof, I, the said Leonard Wray, junior, have hereunto set my
hand and seal, the 31st day of August, in the year of our Lord One