Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The present invention relates to a cartridge for ejecting
liquids under pressure, this incorporating a propellant charge
chamber and a separating device, configured in the form of a driving
sabot that is located between the propellant charge chamber and a
liquid chamber, said sabot consisting of a driving body and a
sealing element that is incorporated at one end.
Such a cartridge that is used to eject liquids under
pressure is known from DE 37 26 490 C2. In this known cartridge/
the driving body is connected to the sealing element by means of a
central pin so as to form a shape or force fit, the sealing element
being configured either as a hollow body with an essentially
spherical face end or being produced from plastic, preferably a
polyurethane foam.
It is the object of the present invention to create a
cartridge of the type described, in which the driving body has
improved mechanical properties and which seals itself within the
barrel of the apparatus.
Accordingly the present invention, comprises a cartridge
for ejecting liquid under pressure, containing a separator in the
form of a sabot that is arranged between a rear propellant charge
chamber and a liquid chamber of the cartridge, said sabot consist-
ing of a driving body and a sealing element that is fitted at the
face end of the driving body, characterized in that the driving
body is configured as a hollow cylindrical body of elastically
deformable material that is open towards the rear propellant charge
chamber and which incorporates a taper at the foremost face end
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starting from a cylindrical area and ending in one piece in a
spherical or near spherical shape which accommodates the elastically
deformable sealing element.
Within the conte~t of the present invention, the sealing
element can be formed from a plastic, preferably from a,polyurethane
foam.
In addition, the outer surface area of the driving body,
together with the sealing element can form a li~uid chamber of
enlargeable volume in the bore of the apparatus, this corresponding
to an essentially radial inlet opening in the barrel of the
apparatus. The driving body can be configured so as to be axially
separable from the sealing element in the bore of the apparatus by
the pressure of the liquid flowing into the liquid chamber.
The special shape of the driving body, as a hollow
cylindrical body that is open at the rear towards the propellant
charge chamber and is of an axially deformable material, has the
advantage that when the powder propellant charge is ignited, the
resulting gases generate a gas pressure within the driving body,
which then forces the surface of the driving body tight against the
inner wall of the barrel of the apparatus. Because of this
particular shape, the driving body has two guide diameters. This
makes it possible to shoot from barrels with diminishing inside
diameters. The rear surface area that corresponds to the calibre
guides the driving body within the cylindrical part of the barrel.
Within the adjacent part of the barrel, within which the inside
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diameter grows continually smaller, the rear part of the driving
body is compressed correspondingly. The foremost guiding diameter
thereupon assumes the centering and guiding function in the narrower
muzzle area of the barrel.
The end-face taper of the driving body that ends at the
front in a one-piece spherical shape leads to improve mechanical
properties of the driving body. The resulting gas pressure acts
axially and optimally within the hollow cylindrcial driving body
and compresses the column of water within the outer liquid chamber.
The foremost spherical taper ensures that the foremost sealing
element releases properly from the spherical taper of the driving
body under the resulting pressure of the liquid, and the driving
body, itself sealed on its outer surface area because of existing
internal gas pressure, forces the column of watex forward at a
very high velocity, constantly and without damage to itself,
adapting to the changing inside diameter of the barrel as it does
this.
One embodiment of the present invention is shown in the
drawings appended hereto. These drawings show the following:
Fig. 1: an embodiment of a sabot of the cartridge in
cross section;
Fig. 2: a complete cartridge to eject liquid under
pressure with the barrel of an apparatusl in cross section.
Within the cartridge 1 that is used to eject liquid, in
particular water, under pressure, a sabot 4 is inserted as a
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separator between a propellant charge chamber 2 and a liquid
chamber 3.
The sabot 4 consists of a driving body 5 that is of
plastic, for example a polyamide, and the sealing element 6 that is
arranged axially at the head of the driving body 5 The driving
body 5 of the sabot 4 is configured essentially as a hollow
cylindrical body, in which the rearmost open face surface 7 is
oriented towards the propellant charge chamber 2. Within this rear
area, the outer surface incorporates a circular groove 8 for
attachment to the cartridge case 13. In the front area, the
driving body 5 is configured so as to have a face-end taper 9 that
ends in one piece in a spherical or similar shape 10 with a
cylindrical guide piece. The diameter of the guide piece
corresponds to the reduced inside diameter of the barrel in the
area of the muzzle (not shown herein). The sealing element 6 that
is of polyurethane foam is installed on this spherical face sur~ace
10 .
In the rear area, with the casing, there are slots 11
distributed around the periphery, and these permit radial movement
of the end surface. The surface 16 of the driving body 5 lies under
slight tension against the inside surface 14 of the bore 15 of the
apparatus.
As can-be seen in figure 2, the whole cartridge consists
of the sabot 4 that is inserted into the cartridge casing 13.
Within the cartridge casing 13, at the rear end, there is a
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26793-45
propellant charge chamber 2 with the necessary propellant charge 27.
The detonator 28 forms the end of the cartridge casing. A sealing
element 6 is installed by force fit in the manner shown on the
front face surface 17 of the sabot 4. The complete cartridge 1 is
located in the chamber ~9 of the apparatus housing 30 with a breech
(not shown herein). The barrel 24 is locked in the housing 30 in
a manner not shown herein. A non-return val~e 31 is arranged in
the essentially radial inlet opening 26 in the barrel 24, and this
is connected to a hydraulic pump 32 by means of a pipe 33. A
further pipe 34 is located between the liquid reservoir 35 and the
hydraulic pump 32.
Thus, the sabot 4 permits the separate feeding and loading
of the drive components, namely the cartridge case 13 with the
detonator 28, the propellant charge 27, the driving body 5, and the
front sealing element 6, as well as the liquid that is to be
ejected, for example water, from the container 35 to the liquid
chamber 3.
The driving components are introduced into the chamber 29
of the barrel 24 from the breech or a corresponding feed system.
The chamber 29 is closed and locked at the rear by means of a
breech (not shown herein). The quantity of liquid that is to be
sealed in is pumped in through the non return valve 31 and through
the inlet opening 26 of the barrel 24 by a hydraulic pump 32 into
the annular chamber 3 between thc sealing element 6 and the driving
body 5 of the sabot 4. Because of the pressure of the liquid the
sealing element 6 separates axially from the driving body 5.
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Because of the liquid that flows in under pressure, the sealing
element 6 within khe bore 15 is moved forward in the direction of
the muzzle, as the outer friction is overcome. When this happens,
the cylindrical portion 18 of the sealing element 6 lies under
slight pressure against the inside surface 14 of the bore 15 so as
to form a seal. Once the introduction of the liquid has been
concluded, there is no longer any pressure available to move the
sealing element 6. The sealing element 6 remains stationary and
thus forms the foremost seal for the liquid within the barrel 24.
During the introduction of the liquid, the driving body 5 was held
in place by the cartridge case 13 and thus forms the rearmost seal
for the liquid.
Once this liquid has been successfully introduced, the
cartridge is ready for firing. On detonation of the cartridge 1,
gas pressure is generated within the internal space 19 of the
driving body 5 and this acts radially against the inner wall 21 of
the driving body as indicated by the arrows 20. This means that
the driving body 5 of the sabot 4 is driven in the direction of the
muzzle, and during this movement it forces the column of liquid in
front of the sabot 4 against the sealing element 6 which is ejected
from the barrel 24. At the same time, because of the gas pressure
20, the middle and rear portions of the driving body that can be
extended radially and elastically lie against the inner wall 14 of
the bore 14 so as to form a seal.
The ejections of the sabot 4 takes place at an extremely
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high velocity, which is in the range of 1,000 m/sec. The water or
liquid that has been introduced is thus driven like a projectile
by the sabot 4 as a result of the pressure caused by the burning
propellant charge 27. When a so-called water hammer of this sort
is used in mining, this column of water with the foremost or front
sealing element 6 is shot into drill holes in the rock. The rock
within the drill hole is broken up because of the very high ejection
pressure, which amounts to several -thousand bar.
