An Improved Method of and Apparatus for Measuring the Power or the Volume of the Gases Resulting from the Explosion of Explosives.
Year: 1896

page_text: Date of Application, 10th Feb., 1896
Complete Specification Left, 10th Nov., 1896-Accepted, 12th Dec. 1896
GESELLSCHAFT-
[Communicated from abroad by SPRENGSTOFF ACTIEN
CARBONIT, of Hamburg, in the Empire of Germany.]
An Improved Method of and Apparatus for Measuring the Power or
the Volume of the Gases Resulting from the Explosion of
Explosives.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, do hereby
declare the nature of this invention to be as follows:-
The improved method and apparatus forming the subject of this invention, are
based upon entirely new principles and allow of directly measuring and indicating
the gas pressure resulting from a given amount of explosive mixtures, and further
of directly measuring the volume of gas formed at that temperature, at which the
explosion takes place-the inner capacity of the explosion chamber being taken
into account.
This new process may be suitably illustrated along with the description of a
constructional form of the apparatus necessary for carrying the process into
practice.
The apparatus substantially comprises two cylinders with pistons working air
tightly therein, one of which pistons receives the gas pressure produced in a closed
vessel or receptacle namely the explosion chamber, and transmits the same to the
second piston, which in its cylinder compresses an elastic medium for example
atmospheric air. From the exactly measurable compression of the likewise exactly
known volume of air the pressure, which has been exerted upon this air volume is
ascertained by "Mariotte's law."
The first cylinder may in form of a screw threaded tube be screwed upon the
explosion chamber, in which the explosive substance preferable in the shape of a
On to the upper
cartridge, is brought to explosion by means of an electric fuze.
extremity of this first cylinder or pressure tube a double threaded nut is screwed,
which insures a simple and completely safe connection of the pressure tube with the
second cylinder and permits of easily dismounting the apparatus after each
measuring operation, for the purpose of being cleaned. The pressure piston
working in the first cylinder is of such longitudinal dimension as to be guided
automatically up to its bighest point.
The lower part of the secord cylinder serves for guiding the piston rod of its
piston and a writing appliance. The piston rod carries at its lower extremity the
dismountable slide block and at its upper extremity the collar piston of the second
cylinder. Upon the slide block a drawing pencil is mounted which projects
outwards through a slot arranged in the second cylinder and which touches the
surface of a drum which can be set in rotary motion by a clock work.
The upper part of the second or pressure cylinder serves for guiding its piston
and is airtightly closed at its top end by a screw cap.
The explosive to be examined is, after its exact weight has first been ascertained,
placed into the explosion chamber and is exploded therein. The gaseous products
resulting from this explosion force the piston of the first cylinder and simultaneously
force the piston of the second cylinder upward. This latter compresses the air

page_text: enclosed in the second cylinder to such an extent that the pressures upon the areas
of both cylinders balance each other. In order to obtain equal proportions of
pressure the second or air piston is preferably of a larger cross section than
the first or driving piston; they consequently form together a differential
piston.
The distance travelled by the second piston is pencilled upon the diagram
surface of the said indicator drum or the like by the writing appliance.
From this distance the pressure can be calculated by taking into account
the cross sections of the two pistons. According to Mariotte's law is equal
P
P
to
if p' is taken to represent the initial and p the subsequent pressure per unit
of area, further taken to be the initial and the subsequent distance between
the piston and the screw cap of the second cylinder.
200
10
-
(200-150) 1
Supposing for instance the air column between the second piston and the screw
cap to be 200 millimeters in height, the first piston to have a cross-sectional area
of one square centimeter, the second piston 10 square centimeters and the distance
travelled to be 150 millimeters, then the pressure exerted by the gases resulting from
the explosion of the explosive would amount to
40 atmospheres.
Further supposing the vessel in which the explosion takes place, to have a capacity
of 5 litres, then the gas volume formed by the explosive at the temperature at
which explosion takes place would at the moment of the explosion, amount
to 40 x 55 = 195 litres. For obtaining very accurate measures there remain
to be taken into account the friction in the interior of the apparatus, the weight of
the pistons and piston rods and the heating of the air volume in the pressure
cylinder, resulting from the compression of the air.
The writing device may be arranged so as to mark the distance, travelled by the
piston, as a straight line or by the aid of the diagram drum, the rotary speed of
which is mechanically adjustable and measurable (for instance by a clock work) as
an explosion curve for the explosive, which permits of obtaining extremely valuable
indications as to speed and force exerted, also as to the explosive power of the
explosive and to directly read such indications.
Instead of applying a gaseous medium also an elastic or unelastic liquid as for
example, glycerine or water, may be used, which however is pushed by the rising
of the second piston through a narrow opening of the cylinder and is thereby
caused to offer a resistance. The quantity of the displaced liquid may serve as a
standard measure of the explosive power.
In another constructional form of the explosion chamber, the arrangement may
be such that a channel, imitating a bore-hole, is bored into a steel cylinder and
connected to the first cylinder of the apparatus.
Dated this 10th day of February 1896.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.
An Improved Method of and Apparatus for Measuring the Power or
the Volume of the Gases Resulting from the Explosion of
Explosives.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, do hereby
declare the nature of this invention and in what manner the same is to be

page_text: performed, to be particularly described and ascertained in and by the following
statement:-
The present invention refers to improvements in and relating to the measuring of
the power or volume of gases resulting from the explosion of explosives or explosive
mixtures.
The said improvements are based upon entirely new principles and allow of
directly measuring and indicating the gas pressure resulting from a given amount
of explosive mixtures, and further of directly measuring the volume of gas formed
at that temperature, at which the explosion takes place the inner capacity of the
explosion chamber being taken into account.
The said invention may be suitably illustrated along with the description of a
constructional form of the apparatus necessary for carrying the same into practice,
and to this end reference is had to the accompanying drawing representing a vertical
sectional elevation of a preferred form of the apparatus.
The apparatus substantially comprises two cylinders a¹ and a with pistons b'
and respectively working air tightly therein, the first of these pistons receives
the gas pressure produced in a closed vessel or receptacle c namely the explosion
chamber, and transmits the same to the second piston 62, which in its cylinder
compresses an elastic medium for example atmospheric air. From the exactly
measurable compression of the likewise exactly known volume of air the pressure,
which has been exerted upon this air volume is ascertained by "Mariotte's
law."
The first cylinder a' may in the form of a screw threaded tube be screwed upon
the explosion chamber c, in which the explosive substance preferable in the shape
of a cartridge, is caused to explode by means of an electric fuse d. To the upper
extremity of this first cylinder or pressure tube al a double threaded nut e is
screwed, which insures a simple and completely safe connection of the pressure
tube a¹ with the second cylinder a² or the intermediate piece as respectively and
permits of easily dismounting the apparatus after each measuring operation, for
the purpose of being cleaned. The pressure piston 61 working in the first
cylinder a is of such longitudinal dimension as to be guided automatically up to its
highest point.
The intermediate piece or lower part as of the second cylinder a² serves for
guiding the piston rod of its piston 62 and a pencil or writing appliance g'. The
piston rod fcarries at its lower extremity the dismountable slide block g and at its
upper extremity the collar piston 62 of the second cylinder a. Upon the slide
block g a drawing pencil g' is mounted which projects outwards through a slot a
arranged in the lower part as of the second cylinder a aul which touches the
surface g of a drum g³ which can be set in rotary motion by a suitable clock work,
not shown in the drawing.
The second pressure cylinder a³ serves for guiding its piston 62 and is closed air-
tight at its top end by a screw cap h.
The explosive to be examined is, after its exact weight has first been ascertained,
placed into the explosion chamber c and is exploded therein.
The gaseous
products resulting from this explosion force the piston of the cylinder a' and
simultaneously force the piston 2 of the second cylinder a upward. This latter
compresses the air enclosed in the cylinder a² to such an extent that the pressures
upon the areas of both cylinders balance each other. In order to obtain equal
proportions of pressure the second or air piston 62 is preferably of a larger cross
section than the first or driving piston ; they consequently form together a
differential piston.
From
The distance travelled by the second piston 2 is pencilled upon the diagram
surface g2 of the said indicator drum or the like by the writing appliance g¹..
this distance the pressure can be calculated according to Marriotte's law by taking into
account the cross sections of the two pistons. According to Marriotte's law 2+ is

page_text: equal to if
-
p¹ is taken to represent the initial and p the subsequent pressure per
unit of area, further taken to be the initial and the subsequent distance
between the piston and the screw cap of the second cylinder.
Supposing for instance the air column between the second piston 63 and the screw
cap to be 200 millimetres in height, the first piston b¹ to have a cross-sectional
area of one square centimeter, the second piston 10 square centimeters and the
distance travelled to be 150 millimeters, then the pressure exerted by the gases
resulting from the explosion of the explosive would amount to
200
10
=
(200-150) T
40 atmospheres.
Further supposing the vessel in which the explosion takes place, to have a
capacity of 5 litres, then the gas volume formed by the explosive at the
temperature at which explosion takes place would at the moment of the explosion,
amount to 40 x 55 195 litres. For obtaining very accurate measures there
remain to be taken into account the friction in the interior of the apparatus, the
weight of the pistons and piston rods and the heating of the air volume in the
pressure cylinder a², resulting from the compression of the air.
=
The writing device may be arranged so as to mark the distance, travelled by
the piston, as a straight line or by the aid of the diagram drum 93, the rotary speed
of which is mechanically adjustable and measurable (for instance by a clock work)
as an explosion curve for the explosive, which permits of obtaining extremely
valuable indications as to speed and force exerted, also as to the explosive power
of the explosive and to directly read such indications.
Instead of applying a gaseous medium also an elastic or unelastic liquid as for
example glycerine or water, may be used, which however is pushed by the rising of
the second piston 62 through a narrow opening not shown in the drawing of the
cylinder and is hereby caused to offer a resistance. The quantity of the displaced
liquid may serve as a standard measure of the explosive power.
For certain purposes it may be expedient to provide an explosion chamber
designed to imitate a bore hole in which case a channel is bored into a steel
cylinder and connected to the cylinder a¹ of the described apparatus.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondents, I declare that what I claim is :-
In an apparatus for measuring the explosive power and volume of the gases
resulting from the explosion of explosives and explosive mixtures the combination
of an explosion chamber (c), a cylinder a', a second cylinder a closed airtight at
its top and attached to the first cylinder by an intermediate part or piece (a),
a piston (2), a piston rod (f) resting upon the head of the piston (1) and being
suitably guided, a writing appliance and a rotating indicator drum, all arranged
and operating substantially as and for the purpose set forth.
Dated this 10th 1
N
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.