IMPROVEMENTS IN DRYING APPARATUS FOR SCIENTIFIC AND CHEMICAL PURPOSES
Year: 1877

page_text: LETTERS PATENT to Frank Wirth, of the Firm of Wirth and Company, Patent
Solicitors, at Frankfort-on-the-Main, in the Empire of Germany, for the
Invention of "IMPROVEMENTS IN DRYING APPARATUS FOR SCIENTIFIC AND
CHEMICAL PURPOSES." A communication from George Crespel, of Frankfort-
on-the-Main in the Empire of Germany.
Sealed the 24th April 1878, and dated the 30th October 1877.
PROVISIONAL SPECIFICATION left by the said Frank Wirth at the Office
of the Commissioners of Patents on the 30th October 1877.
FRANK WIRTH, of the Firm of Wirth and Company, Patent Solicitors, at Frank-
fort-on-the-Main, in the Empire of Germany. "IMPROVEMENTS IN DRYING APPA-
RATUS FOR SCIENTIFIC AND CHEMICAL PURPOSES." A communication from George
Crespel, of Frankfort-on-the-Main, in the Empire of Germany.
This Invention has for object the construction of new or improved drying appa-
ratus for scientific and chemical purposes, and it consists of a deep square compart-
ment or receiver furnished with a thermometer, and placed in an outer cylindrical
case in such manner as to leave a space between the bottom and around the sides of
the receiver. This space is filled with water introduced through a glass pipe or
tube acting as a water gauge, and provided with a funnel and stop-cock. An air-
heating apparatus placed at the bottom of the outer case receives its heat from a gas
burner (although petroleum, spirits of wine, super-heated steam, or discharged steam
may be used) and raises the steam coming from the water to high pressure.
gas burner is regulated so as to cause the hot air in the air-heating apparatus to
ascend into the receiver or drying space through a pipe.
The
The outer case is provided with a pressure gauge and safety valve to regulate the

page_text: temperature and pressure of the water. This apparatus is preferable for laboratories,
as the degree of heat can be regulated at will.
The drying compartment is covered with a woollen stuffed cover so as to prevent
loss of heat by evaporation or radiation. Through this cover passes a rod termi-
nating at each end in a polished plate, the substance to be dried being placed on the
plate in the drying compartment. This rod is in connection with a beam provided
with a graduated quadrant, and is mounted on an axis resting in bearings on the
top of the cylindrical case. On the same axis is also mounted an index or pointer,
so that when the balance is regulated by means of weights placed in the other plate,
the index or pointer and the beam are always parallel. To prevent any error in
reading off the graduations the pointer is terminated in two parallel pieces placed
at right angles to the beam axis.
For fine or sensitive chemical analysis I use a pulley or drum, through which
passes an axis mounted slightly excentrically in two supports fixed to the top of the
outer case, so as to cause the pulley or drum to stand at a fixed point.
The plate on which the substance to be dried is placed is attached to a button
fixed to the pulley or drum, and a weight attached in a similar way also to this
pulley balances the plate. A pointer or index mounted on the axis of the pulley
stands at the utmost limit of a fixed graduated scale when the plate is empty.
The loss of water from the substance to be dried is indicated in both apparatus
by the difference of position of the index on the quadrant.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Frank Wirth in the Great Seal Patent Office on the 29th April
1878.
FRANK WIRTH, of the Firm of Wirth and Company, Patent Solicitors, at Frank-
fort-on-the-Main, in the Empire of Germany. "IMPROVEMENTS IN DRYING APPA-
RATUS FOR SCIENTIFIC AND CHEMICAL PURPOSES." A communication from George
Crespel, of Frankfort-on-the-Main, in the Empire of Germany.
This Invention has for object the construction of new or improved drying appa-
ratus for scientific and chemical purposes, and it consists of a deep square compart-
ment or receiver, furnished with a thermometer, and placed in an outer cylindrical
case in such a manner as to leave a space between the bottom and around the sides
of the receiver. This space is filled with water, introduced through a glass pipe or
tube acting as a water gauge, and provided with a funnel and stop-cock. An air-
heating apparatus placed at the bottom of the outer case receives its heat from a gas
burner (although petroleum, spirits of wine, superheated steam, or discharged steam
may be used), and raises the steam coming from the water to high pressure. The gas
burner is regulated so as to cause the hot air in the air-heating apparatus to ascend
into the receiver or drying space through a pipe.
The outer case is provided with a pressure gauge and safety valve to regulate
the temperature and pressure of the water. This apparatus is preferable for labora-
tories, as the degree of heat can be regulated at will.
The drying compartment is covered with a woollen stuffed cover so as to prevent
loss of heat by evaporation or radiation. Through this cover passes a rod, termi-
nating at each end in a polished plate, the substance to be dried being placed on
the plate in the drying compartment. This rod is in connection with a beam pro-
vided with a graduated quadrant, and is mounted on an axis resting in bearings
on the top of the cylindrical case. On the same axis is also mounted an index or
pointer, so that when the balance is regulated by means of weights placed on the
other plate, this index or pointer and the beam are always parallel. To prevent
any error in reading off the graduations the pointer is terminated in two parallel
pieces placed at right angles with the beam axis.
For fine or sensitive chemical analyses I use a pulley or drum, through which
passes an axis, mounted slightly excentrically in two supports fixed to the top of the
outer case, so as to cause the pulley or drum to stand at a fixed point.
The plate on which the substance to be dried is placed is attached to a button
fixed to the pulley or drum, and a weight attached in a similar way also to this
pulley balances this plate. A pointer or index mounted on the axis of the pulley
stands at the utmost limit of a fixed graduated scale when the plate is empty.
The loss of water from the substance to be dried is indicated in both apparatus
by the difference of position of the index on the quadrant.
I now proceed to describe with reference to the accompanying Drawings a drying
apparatus constructed according to my Invention, and shewn in connection with a
balance.
Figure 1 is a side elevation, partly in section, and Figure 2 is a plan.
Figure 3 shows a further arrangement or modification.
A is the drying apparatus, to which is fastened the balance B.
This drying apparatus consists,-
1st. Of the gas-heating burner a; but in place of gas, petroleum, spirits of wine,
superheated steam, or discharge steam can be used.
2ndly. Of the drying apparatus proper A, consisting of an outer cylinder b, in
which a four cornered receiver (but round in high-pressure or chemical balances) is
placed in such a position that a free space remains between it and the bottom and
sides of the outer cylinder, which is filled with water for the pipe i. This pipe i
bas a funnel mouth-piece h for pouring in water; and a stop-cock / for carrying off
the steam at high pressure. An air-heating apparatus d, regulated by the tap e, is

page_text: situated over the gas burner a, which is regulated by the tap f, and the hot air is
caused to ascend into the drying space through the pipe g.
い
3rd. Of the thermometer l.
4th. Of the water gauge m', m, which shows in a low-pressure apparatus, when
the water is too low, that is to say, when the water line is below m, and steam
comes out at m³, fresh water must then be poured in.
5th. Of the double polished metal plates n, with woollen stuffing 'n' between them
to prevent cooling down by evaporation (therefore polished so as to fit tight), or by
radiation prevented by the wool n¹.
6th. Of light-pressure apparatus.
1
o is a manometer or pressure gauge, and p is a safety valve, which can be regu-
lated at will so as to ensure safety to the apparatus, but chiefly for regulating the
temperature and pressure of the water, so that on cooling down to low pressure at
least 100° can be kept with dry pressure, the pressure can be 160° and more, so that
this apparatus is preferable for laboratories to either gas or petroleum, as the neces-
sary amount of heat can be regulated to a degree.
C, Fig. 4, is an apparatus with wooden or non-conducting handle, consisting of
water glass, try cock, float, or the like, to show the height of the water.
The balance B, shewn in the annexed Drawings, when well made, is very suitable
for this purpose, and rarely met with.
The balance scale is hung in such manner on the pin that it can be easily taken
off to be filled and replaced; this scale hangs on the wire, passing through a slit
in the lid or cover of the drying apparatus. At the top placed an adjusting scale
g for receiving the adjusting weights; this is used first, when the loss of water is
over 25°, to equalize which a 5 gr. weight is used; or when handling bulky sub-
stances which dry with difficulty, which is often the case, a small weight, e. g., gr.
can be used, so that the balance stands equal at 15 gr. tara.
The balance B is provided with an axis s, which rests in the journals W and H,
it has also a graduated scale t, divided very distinctly into 5 gr. and decigrammes.
When the balance scale is at its lowest, that is to say, when weighted with 20 gr.,
the graduated scale shows 12° exactly; this is sufficient for almost all technical
purposes.
The hand or pointer u is placed on the same axis with the balance, so that when
regulated the two remain always parallel. It must however be specially remarked
that this hand consists of two pieces of metal u¹ and u², placed parallel to each
other, and at right angles to the balance axis s; in this manner, in spite of the
distance of u¹ from the balance beam, I effectually prevent any mistakes. When
this balance is required for fine chemical analyses it is then provided with a vertical
pulley, the cylinder v fitting on the tube h, m.
•
A spring scale, in a somewhat similar form to a Salter's family scale, can also be
used, this is however not reliable or sensitive, but simple in construction.
The new excentric balance shewn in the Drawing, Figure 3, and very appro-
priate for this purpose, consists of a cylinder a*, 12 centimeters in diameter, and
12 cm. long, made of thin tin, exactly cylindrical, and with two flat bottoms,
through which passes the axis b*, fixed excentrically, of some 2m/m the smaller the
amount of excentricity the more sensitive the balance; this causes the cylinder to
stand at a² in a steady balance. A bent pointer *, made of thin steel wire, moving
on the quadrant ix, is attached to the cylinder at b*. The scale g* is attached by
a thin silk cord to ex, the weight fx being attached in the same way, and being so
constructed that when the scale is weighted with 20 gr. the pointer stands at k. If
any substance to be tested by drying be placed in the scale gx, and the latter let
into the drying apparatus, the pointer h* will show on the quadrant the difference
in weight, that is to say, the amount of water contained in the substance.
A horizontal drying apparatus, with a bar balance and weight on the same, to be
moved backwards and forwards, can be used, but is not advisable.
To use the apparatus it must first be filled with water, then heated, and as much
. of the substance to be dried is then placed on the balance scale g* till the hand

page_text: points to 20; the balance is then tried to see whether it be true by putting on a
20 gr. weight, and if this be not the case the same can then be adjusted either by
moving the weight on the balance or by screwing the pointer until it stands right.
The balance can also be regulated by the adjusting scale and weights.
The temperature rises in the apparatus up to 100°, and the balance scale rises as
the substance becomes lighter, that is, it loses water; this loss is shown by the
pointer on the scale in grammes or decigrammes.
•
In chemical balances the loss is equalized, so that it does not matter if the arms
of the balance are not equal.
For fixing the specific gravity of substances also when dried to 100° the drying
apparatus is filled with water, and the body is placed in the adjusting scale
5:10:20 and then in the lower scale; and in this manner the loss of weight is
just as accurately shown by the pointer on the quadrant or graduated scale as the
specific gravity. For this purpose, however, a special scale is attached, which
plainly shows any faults in the scale or beam. This apparatus thus shows in an
instant the specific gravity of the heaviest bodies, as well as that of the lightest, it
will also show a good from a bad piece of money, the scale giving the amount of
weight wanting.
Having now described the nature of the said Invention, and in what manner
the same may be performed, I declare that I claim, the improved drying appa-
ratus for scientific and chemical purposes, substantially for the purpose and in the
manner as shewn and described.
In witness whereof, I, the said Frank Wirth, have hereunto set my hand and
seal, this Eighteenth day of April, in the year of our Lord One thousand
eight hundred and seventy-eight.
FRANK WIRTH. (L.S.)