GB2070928A - Device for piercing and injecting fluid through a wall - Google Patents

Abstract

A device for piercing a wall and then injecting a fluid through the wall, essentially for the use of intervention personnel such as the police force or the fire service, comprises a piston which can be driven forwards in its cylinder (1) by a high-pressure gas produced by a pyrotechnic charge (3) to project a tubular rod (5) fixed to the piston through the forward end of the cylinder. The piston rod (5) is tubular and provides an injection channel; and the piston is equipped with a duct (17, 24) for communicating the injection channel with an inlet opening (9) for the injection fluid, the inlet to the piston duct being blocked by the cylinder except when the piston has been driven forwards to its final position against the forward end (7) wall of the cylinder. <IMAGE>

Description

SPECIFICATION Device for piercing and injecting a fluid through a wall The invention relates to a device which is capable of piercing through a resistant wall and then injecting a fluid through the wall, and which is intended essentially for intervention personnel such as the police force or the fire service.

In many cases where a very rapid intervention is necessary, it may be helpful if an active fluid can be injected through a resistant wall such as a dividing wall of a building or a closed door. This may be the case, for example, when persons barricaded in a room or the cockpit of an aircraft are to be immobilised by injecting a fluid having an immediate physiological action, or when a fire limited to a particular room is to be fought by injecting an extinguishing fluid.

The equipment available, at present, to intervention personnel does not make it possible to inject a fluid rapidly through a wall. The object of the invention is to make it possible, successively, but virtually instantaneously, to penetrate a resistant wall and then inject a fluid through this wall, using a portable device which is easy to handle, is reliable and offers absolute safety for the user.

According to the invention there is provided a device for piercing a wall and injecting a fluid into the space on the remote side of the wall, the device comprising a cylinder, a piston received in the cylinder and defining therewith a drive chamber located rearwardly of the piston, which drive chamber can be subjected to a fluid at high pressure for driving the piston forwardly with respect to the cylinder, and a rod fixed to the piston and project nag forwardly therefrom to slide through the forward end wall of the cylinder when the piston is driven forwards, the rod being tubular to define an injection channel for the fluid to be injected, the cylinder having an inlet for injection fluid arranged to communicate with the injection channel through a duct in the piston when the piston is driven forwardly to a position substantially in abutment with said forward end wall of the cylinder, and the inlet to said duct being blocked by the cylinder when the piston is located rearwardly of said position.

The piston may be circular and the cylinder a cylindrical shell.

Alternatively, the effective surface of the piston exposed to the drive chamber can be annular, and the cylinder comprise a periph eral shell and an internal pipe between which the drive chamber is confined.

The inlet of the piston duct can be directed laterally and the duct advantageously extends longitudinally and is blocked at the rear end of the piston.

Preferably, the drive fluid is a gas produced by the combustion of a pyrotechnic charge, and, advantageously, this charge is accommodated in the rear end of the cylinder.

According to a special embodiment, the inlet opening of the cylinder communicates with a reservoir of active fluid containing substantially the quantity of fluid which is to be injected, which is of advantage when this active fluid is a gas having a very rapid physiological effect, such as a paralysing gas.

The free end of the rod preferably terminates in a point for piercing the wali, and injection orifices for discharging the injection fluid preferably open laterally of the rod.

The advantages obtained by means of this invention are essentially that the active fluid is introduced into the injection channel of the piston rod only when this piston is near its final position, this introduction being automatic and not occurring until after the piston rod has drilled through the wall to which the injecting drill is applied.

The invention is described in more detail below by means of drawings illustrating three different exemplary embodiments.

Figure 1 shows, in axial section, a first exemplary embodiment of a device according to the invention; Figures 2 and 3 show, in axial half-section, another embodiment of the invention, Fig. 2 corresponding to the left half-section of the device in an initial position, and Fig. 3 corresponding to the right half-section of the device in the final position; and Figure 4 shows, in an external view with partial sections, a device embodying the invention and adapted to be hand held.

Referring to Figure 1, the injecting drill comprises a cylinder body (1) to which is screwed at the upstream end the plug (2) containing a propulsive charge (3), and to which is screwed at the downstream end the terminal ring (4) which ensures the guidance of the tubular drilling rod (5). The cylinder body contains in its downstream part four vent-holes (6) which issue internally near the shock-absorbing washer (7) which is made of hard rubber and is stuck to the terminal ring (4), itself covered on its outer annular face by a soft rubber washer (8). The inlet opening (9) which is provided laterally in the central part of the cylinder body is connected by a weld to the inlet pipe (10) which is bent and ends in a screw-threaded union (11) to which is fixed the flexible hose (12) supplying the active fluid.This pipe (10) is held rigidly on the cylinder by means of the arm (13) which is used to fix the ignition leads of the electric igniter (14) placed in the propulsive charge (3). This propulsive charge is confined in the upstream part of the plug (2) by means of the lid (15), and this plug has a decompression screw (16). The piston rod (5) is made of high-strength alloy steel and its downstream end is bevelled, whilst its upstream end is inserted and screwed into the piston head.

This piston head is tubuiar, the axial bore (17) having the same diameter as the bore of the rod (5), and this head possesses a peripheral recess (18) which provides, on the one hand, in its downstream part a guide bearing (1 9), equipped with a sealing ring (20) located downstream of the inlet opening (9), and, on the other hand, in its upstream part two bearings which are separated by the inlet recess (21) and which are each provided with a sealing ring (22 and 23). the transverse inlet duct (24) opening into this inlet recess (21) and intercepting the axial bore (17).

In operation, the vessel of active fluid to which the flexible hose (1 2) is connected is opened and this fluid penetrates into the pipe (10) and into the peripheral recess (18). The injecting drill is kept firmly in contact with the wall to be drilled, the washer (8) permitting sufficient local sealing, and an electrical pulse is transmitted to the igniter (14). The ignition of the propulsive charge (3) generates a virtually instantaneous pressure rise which ensures that the lid (15) is ruptured and that the whole of the piston is then ejected, the bevelled end of the tubular rod of said piston drilling through the wall to which the injecting drill is applied.The air located downstream of the piston is expelled through the vent-holes (6) and, when the piston almost comes up against the shock-absorbing washer (7). the inlet recess (21) communicates with the inlet opening (9) and the active fluid then flows through the inlet duct (24) and the axial bore 17, and is injected through the wall to which the injecting drill is applied.

Referring to Figs. 2 and 3, the injecting drill has a cylinder body which is constituted by a long peripheral shell (30) and by an inner pipe (31), which are connected and positioned relative to one another by means of the cylinder plug (32) which possesses at its outer end a spot-facing and a thread (33), permitting the leaktight connection of a vessel of active fluid (not shown), and which possesses on its periphery a spot-facing and a thread (34) permitting the leaktight connection of a high-pressure gas generator (not shown).The cylinder body has in its downstream part four vent-holes (35) and an end thread which enables the terminal ring (36) to be fixed, this ring ensuring the guidance of the tubular boring rod (37) and being provided internally with a shock-absorbing washer (38) made of lead and externally with a sealing washer (39) made of soft cellular rubber The downstream end of this tubular rod (37) is threaded to receive a drilling head which is adapted to the material of the wall to be drilled. and the upstream end is force-fitted in the downstream element (40) of the piston head. which is hollow. This head has a tubular transfer chamber (41) which forms, with the four channels (42), the whole of the inlet duct, which can be made to communicate with the inlet opening constituted by the downstream end of the inner pipe (31) of the cylinder body.The downstream element (40) of the piston head is rendered integral with the upstream element (43) by means of the outer skirt (44), the inner skirt (45) being fixed to the downstream element only and possessing at its free end a sealing ring in contact with the inner pipe (31).

The manual injecting drill shown in Fig. 4 has an internal construction similar to that illustrated in Fig. 1. The tubular rod (51) providing an injection channel ends in a pyramidal point (52), and the lateral injection orifices (53) which pass through this rod issue at the level of the shock-absorbing washer (54) made of hard rubber. Two identical metal handles are fixed at right-angles to one another on the body of the cylinder (55) by means of a weld (56), the upstream handle (57) containing the access (58) for the two ignition leads, one of the leads being connected directly to the igniter of the pyrotechnic plug (59), whilst the other lead possesses in series two contactors controlled by the pushbuttons (60 and 61) placed respectively on the upstream handle (57) and on the orthogonal downstream handle (62).

Tests conducted with a prototype made according to Fig. 4 and having a total length of 50 centimetres and an outside cylinder diameter equal to 5 centimetres have made it possible to obtain satisfactory results in tests involving drilling throgh a sheet of mild steel 2 millimetres thick, a sheet of duralumin 2.5 miliimetres thick and a hollow wooden door comprising two panels 6 millimetres thick.

Although not shown in Fig. 4, it will be understood that the cylinder (55) has an inlet for the active fluid positioned in similar manner to the inlet (9) in the Fig. 1 embodiment.

Claims (8)

1. A device for piercing a wall and injecting a fluid into the space on the remote side of the wall, the device comprising a cylinder, a piston received in the cylinder and defining therewith a drive chamber located rearwardly of the piston, which drive chamber can be subjected to a fluid at high pressure for driving the piston forwardly with respect to the cylinder, and a rod fixed to the piston and projecting forwardly therefrom to slide through the forward end wall of the cylinder when the piston is driven forwards, the rod being tubular to define an injection channel for the fluid to be injected, the cylinder having an inlet for injection fluid arranged to communicate with the injection channel through a duct in the piston when the piston is driven forwardly to a position substantially in abutment with said forward end wall of the cylinder, and the inlet to said duct being blocked by the cylinder when the piston is located rearwardly of said position.

2. A device according to claim 1, wherein the effective surface of the piston exposed to the drive chamber is annular, and the cylinder comprises a peripheral shell and a coaxial inner pipe, the drive chamber being confined between the shell and pipe.

3. A device according to claim 1, wherein the inlet of the piston duct is directed laterally with respect to the axis thereof.

4. A device according to one of claims 1 or 2, wherein the piston duct extends longitudinally and is blocked at the rear end of the piston.

5. A device according to claim 1, wherein said inlet of the cylinder body communicates with a reservoir of fluid containing substantially the quantity of fluid to be injected.

6. A device according to any one of claims 1 to 5, wherein the injection fluid is a gas having a very rapid physiological effect, such as a paralysing gas.

7. A device according to any one of claims 1 to 6, wherein the drive fluid is a gas produced by the combustion pf a pyrotechnic charge connected to the drive chamber.

8. A device for piercing a wall and injecting a fluid into the space on the remote side of the wall, substantially as herein described with reference to the drawings.