JPH0560490A - Liquid mass arm device - Google Patents

Abstract

PURPOSE: To obtain an electric mechanism for igniting a liquid bursting charge used by a regenerative piston system by connecting a precombustion chamber for ignition having electrodes and an inlet port for liquid bursting charge to a main combustion chamber through a conduit and an orifice. CONSTITUTION: A housing 10 having a main combustion chamber 12, a precombustion chamber 14 for ignition, and a conduit 16 connected to the chambers 12 and 14 is provided to an ignition system. The cross-sectional area of the conduit 16 is made smaller than those of the chambers 12 and 14, and the opening of the conduit 16 to the main combustion chamber 12 is limited by means of an orifice 18. A valve 36 is opened to fill up the precombustion chamber 14 and conduit 16 with a liquid propellant under a high pressure and to push out the propellant into the main combustion chamber 12. Then the valve 36 is closed, and an electricity supplying source is connected to electrodes 20 and 22 so as to make an igniting current pass through the liquid bursting charge in the precombustion chamber 14. Since the current generates bursting charge decomposing heat, a cracked gas is generated and the liquid bursting charge in the conduit 16 is discharged into the main combustion chamber 12 and fires the bursting charge in the chamber 12.

Description

Description: FIELD OF THE INVENTION The present invention relates to a weapon device using liquid propellant, and more particularly to an ignition mechanism for such a device.

(Prior Art) Liquid propellant guns are well known, for example US Pat. No. 4,023,463 issued to DP Tass on May 17, 1977, and E. Ashley on October 4, 1977. No. 4,051,762, and U.S. Patent Application No. 178,254 filed on August 7, 1980 by M. Bulman. This type of gun, which is fired with non-hypergolic propellants, requires an initial pulse of high temperature, high pressure gas in the combustion chamber to initiate the firing operation for each shot. To do.

 For repeated firings, continuous pulses must be delivered. When a signal detonator is used, the detonator consumed after each shot must be replaced, as shown in US Pat. No. 4,051,762. As an alternative, certain monopropellants were issued to JJ Scanlon on January 30, 1968 in U.S. Pat. No. 3,576,103, and E. Ashley on Nov. 4, 1980. It can be ignited by adiabatic compression as shown in US Pat. No. 4,231,282. Even when an electric arc is used for ignition, the propellant must be exposed to sufficient temperature and pressure to confine it and burn the entire charge. This condition is most easily achieved in high load systems where the combustion chamber is completely filled with propellant. In regenerative piston systems, the combustion chamber is relatively propellant-free at ignition.

 It is an object of the present invention to provide an electrical mechanism for ignition of a liquid propellant which is especially adapted for use in regenerative piston systems.

 A feature of this invention is an ignition pre-combustion chamber having a first cross-sectional area, an electrode, and an inlet port for liquid propellant, a conduit having a length ratio greater than 1 compared to a direct diameter, A device for an ignition mechanism for a main combustion chamber including a second cross-sectional area smaller than a cross-sectional area and an inlet opening into the ignition pre-combustion chamber or an outlet opening through an orifice to the main combustion chamber. ..

(Description of Embodiments) FIG. 1 shows a basic ignition system according to an embodiment of the present invention. It defines the areas of ignition and auxiliary charge loading during the ignition phase of the gun firing cycle.

 It includes a housing 10 having an ignition system, a main combustion chamber 12, an ignition pre-combustion chamber 14, and a conduit 16 communicating between the two chambers. The cross-sectional area of this conduit is smaller than the cross-sectional area of each of these chambers. The opening of the conduit 16 to the main combustion chamber 12 is restricted by the orifice 18. The ratio of the length of the conduit 16 to the diameter is greater than 1. The length and diameter of conduit 16 should, of course, be selected as a function of desirable ignition performance characteristics, such as total energy delivered to the main combustion chamber, peak pressure in the main combustion chamber, repetition rate, etc. I have to. The electrode 20 projects into the ignition pre-combustion chamber and is spaced from the electrically conductive side wall 22 of this chamber by an annular gap 24. This side wall serves as the second electrode. The electrode 20 is fixedly insulated by a solid insulating bead 28 in a cavity 26 in the housing. The insulating bead 28 is secured by a threaded annular mechanical element 30. Alternatively, the electrode assembly can be modified as shown in US Pat. No. 4,215,620 issued August 5, 1980 to D.P. Trassie. A source 32 of liquid propellant under pressure is connected to the ignition precombustion chamber via conduit 34 and valve 36.

 An electrical source (not shown) to the valve 36 and electrodes is provided during each gun firing cycle by a cylindrical cam as shown in US Pat. No. 3,763,739 issued October 9, 1973 to DP Tassie. It is controlled in synchronization with.

 In operation, valve 36 is first opened to fill liquid propellant into the combustion precombustion chamber 14 and conduit 16 under high pressure to fill all residual air and residual combustion gas from there. Extrude into the combustion chamber. The valve 36 is then closed and a conventional charged capacitor, an electrical source, is coupled to the electrodes 20 and 22 and discharged across the electrodes. This ignition current passes through the liquid propellant in the ignition precombustion chamber. This current produces heat that decomposes some propellant. This decomposition produces gas. The gas tries to spread into the conduit but is resisted by the liquid propellant. The liquid propellant is stationary within the conduit and acts as an inertial cylinder or an inertia plug. This inertial cylinder contains the liquid propellant in the pre-combustion chamber and allows the initiation of the combustion of the liquid propellant and the development of an appropriate gas pressure in the pre-combustion chamber for the propagation of this combustion. The gas / liquid interface advances through the pre-combustion chamber to conduit 16. The liquid propellant in the conduit is gradually accelerated under the pressure of the combustion gas and discharged into the main combustion chamber. The ejected liquid propellant itself continues to actively burn and acts as an auxiliary charge that ignites the liquid propellant in the main combustion chamber.

In a typical system, conduit 16 has a diameter of about 3.18 mm (0.125 inches) and a length of about 47.9 mm (1.885 inches), and its orifice has a diameter of about 3.18 mm (0.125 inches). The pre-combustion chamber 14 is about 6.35 mm (0.25 inch) in diameter and has an electrode gap of about 2.39 mm (0.094 inch). Figure 2 shows the functionality of this typical system for a 1 ms time interval of particular interest. Current flow between the electrodes, at 700 amps for generating a peak pressure of ignition precombustion chamber 14 to approximately 4780kg / cm ² to about the peak pressure and the conduit 16 of ^{(68,000psi) 3867kg / cm 2 (} 55,000psi) You can see that there is.

 FIG. 3 illustrates a modification of the mechanism of FIG. 1 incorporated into a liquid propellant differential piston cannon of the type shown in U.S. Patent Application No. 178,254.

 The gun of FIG. 3 incorporates a barrel 50 which is fixed within a housing 52. The barrel portion 50 has a calibrated barrel cavity 54, a shell receiving chamber 56 and an intermediate ridge 58. A bullet 60 having a band 62 is housed in an axial bore 66 in the housing and is fixed by a bolt 64. The housing is coaxial with the barrel 54 and the breech bolt 64 is adjusted by a cylindrical cam and cam follower assembly 67.

 The breech bolt 64 includes a breech bolt body 68 having a frustoconical conical front portion 70 having a breech floor 72 and an axially hidden inner bore 74 terminating at the rear of the breech floor 72. A plurality of radially oriented bores 76 extend between the front end of bore 74 and the outer surface of the conical surface. The electrode 78 is secured to the rear end of the lumen 74 by an insulator tube 80 and has a front portion that projects into an enlarged portion 82 of the lumen 74. A plurality of radial conduits 84 extend from the lumen expansion 82 to the exterior of the breech bolt body. The free bottom main body 68 slides and is sealed in two annular seals 86 and 88 fixed to the two annular grooves 90 and 92 of the inner cavity 66, respectively. A conduit 98 through housing 52 communicates from a pressurized source of liquid propellant to an annular groove 99 in axial bore 66. The breech bolt 64 is reciprocated within the bore 66 by a cylindrical cam such as that shown in US Pat. No. 4,244,270 issued to D.P. Tassie on October 9, 1973. Annular seal 88 may be of the type shown in US Pat. No. 4,050,352 issued September 27, 1977 to D.P.Tassie. This cylindrical cam allows the breech bottom to be in the rearmost position with the breech tube 84 at the rear of the seal 86, the middle position where the breech tube 84 is in the correct relationship with the housing groove 99, and the breech tube 84. Reciprocates between the foremost positions at the front of the seal 88. When this breech bolt is in its rearmost position, liquid propellant charges through the conduits 98 and 84 from the pressurized reservoir to the lumen expander 82 and inertia conduit or It can be metered into the remainder of the lumen 74, which serves as a cylinder.

 The barrel and housing define a generally hollow cylindrical valve 136 therein and a generally hollow cylindrical cavity 134 in which a generally hollow cylindrical piston 138 is housed.

 Cylindrical valve 136 includes an inner wall surface 142 providing an annular gap or a front annular portion 140 having a passage 144 proximate an outer wall surface 146 of the barrel. The annular portion 140 includes an inner wall surface 154 providing an annular cavity 156 proximate the outer wall surface 146 and an outer wall surface 158 providing an annular cavity 160 proximate the housing inner wall surface 150. It forms a complete body with the middle annular portion 152 having. The intermediate portion 152 includes an inner wall surface 164 journaled to the outer wall surface 166 of the barrel, and a transverse rear surface 168, a transverse front surface 170, and an inner annular cavity 172, surfaces 168 and 170 substantially sealed thereto. It forms a complete body with a rear annulus 162 having a plurality of longitudinal lumens or passageways extending therethrough and an annular seal 176 located in an annular groove in the outer wall surface 158. A plurality of longitudinal lumens 177 provide a passageway between cavity 156 and cavity 172 when valve 136 is in its rearmost position.

The two rods 178 each have a rear end fixed to the front annular portion 140 and extend through a lumen within the housing. The rods are each biased in the rearward direction by respective spiral spring compression springs 310 captured between the rod-shaped lateral pin and the housing plug. Each rod may have its own seal not shown.

 Piston 138 includes a front annular portion 190 having an inner wall surface 192 supported on valve surface 158 and an outer wall surface 194 spaced from housing surface 150. The annular portion 190 is supported by an inner surface 192 which bears on the valve's annular seal 176 and an annular seal 202a which carries an intermediate tubular portion 196 having an outer surface 200 which is arranged in an annular groove of the housing inner surface 204. It is one. The O-ring 202b backs up the annular seal.

 The intermediate portion 196 is integral with a rear annular portion 206 having an annular shaped foot valve 208 mounted thereon. The rear annular portion 206 is typically self-biased to bear against and seal on the rearmost portion 166a of the barrel barrel outer surface 166. The foot valve 208 has a notch in it. This allows the diameter of the ring to increase under internal counter pressure. The effective cross-sectional area of the front surface 214 of the rear annular portion 206 is smaller than the effective cross-sectional area of the rear surface 212, providing a piston sleeve 138 with a differential piston function.

 The barrel 50, the valve 136 and the piston 138 may be considered to define a liquid propellant filled cavity 156, a valve cavity 172, a pump cavity 218 and a combustion chamber cavity 220 according to their relative positions. The barrel 50 has a first plurality of radial passages 226 which serve as passages between the pump chamber 218 and the bore 54.

 A supply means 251 for supplying high pressure liquid propellant is coupled to the cam control valve 252. The cam control valve is coupled to the housing inlet which leads to the housing annular passage 254. From the passage 254, a plurality of radial lumens 256 lead to a front portion of the surface 150.

A radial lumen 258 leads through the surface 150 to the rear annulus 190 of the piston 138 for drainage from the surface. The supply means 251 is coupled to the conduit 98 via a cam controlled valve 259.

 Two rods 207 and 272 have rear ends fixed to the front annulus 190 of piston 138, respectively, and extend through the lumen with spacer 146 and housing seals. The forward ends of these rods each terminate in an enlarged section. Cylindrical cams such as those shown in U.S. Pat. No. 3,763,739 have spiral control tracks. A cam follower with an arm terminating in the follower of the rod rides on the control track. The rods are free to move the followers forward, but the cam track through the followers restrains their movement in the rearward direction. The cam track also allows the rod to be pulled forward via the follower.

 The barrel 50 has an enlarged portion 300 with the inner surface 154 of the valve 136. A plurality of substantially axial lumens 177 are arranged in an annular row through the dilation to serve as a passageway from the filling annular cavity 156 to the valve cavity 172. A plurality of axial lumens 174 serve as passageways from valve cavity 172 to pump cavity 218. When the pressure differential between the pump cavity 218 and the combustion chamber 220 exceeds the natural excursion of the foot valve 208, it causes an outer surface 166a of the barrel and a passageway from the pump cavity 218 to the combustion chamber 220. Valve 208 is forced to open to provide a gap between the valve and the valve acting.

 The dish washer 306 is mounted in a valve cavity 172 on the barrel that approaches the lumen 177 and is retained by a retaining ring 308. This washer is typically conical in shape and flows liquid propellant from the fill cavity 156, through passage 177, around washer 306, through valve cavity 172, and through passage 174 into pump cavity 218. To enable. Prior to firing, differential valve 136 is retained within the piston shown in FIG. 3 by an external compression spring 310 coupled to rod 178. As such, the surface 166 of the valve head 162 closes the radial lumens 226 and prevents the flow of liquid propellant from the pump cavities 218 into these lumens. At the start of firing, the pressure of the liquid in this pump cavity 218 rises and is transmitted to the valve cavity 172. The increase in this pressure on the rear face of the washer 306 compared to the pressure on the front face of the washer separates the filling cavity 156 and the system in front of it from the liquid pressure of the shock produced during firing. Will force the washer to flat against the force of its original spring, which is forcing 177 to close. During firing, the valve head front surface 170 has a smaller cross-sectional area than the rear surface 168 so that the differential force generated thereby reduces the volume of the valve cavity 172 to substantially zero. The valve 136 is forced forward against the bias of the spring 310 to uncover the lumen 226.

 In the embodiment shown in FIG. 3, the firing passes current from the cam controlled current source 37 to the exposed end of the electrode 78 and the inner wall of the lumen expansion 82, producing hot gas, It is initiated by passing hot gas through lumen 74 and vent 76 into combustion cavity 220. The high pressure gas exerts a force on the rear surface 212 of the piston head 206 to force the piston forward, increasing the pressure in the pump cavity 218 and opening the foot valve 208 which provides an annular gap. Liquid propellant is forced out of the pump cavity 218 through this annular gap into the combustion cavity 220, where it is ignited by hot gas. The front face 214 of the piston head has a smaller cross-sectional area than the rear face 212 so that the differential force created continues to flow through the annular gap of liquid propellant, causing the piston to move forward. Force extrude. At a predetermined gas pressure within the combustion chamber, the band 62 of the ammunition is carved by the ridge, and the ammunition advances forward in the gun cavity and opens the lumen 226.

Since the valve head 162 has already opened these lumens, the liquid propellant passes freely through these lumens, from the pump cavity 218 to the rear end of the cannon, and into the cannon. Supplies the propellant. The inner surface of the barrel is subsequently burned and the outer surface of the barrel is subsequently refueled. In the event of a misfire, both the differential valve 136 and the disc washer valve remain in their initial open configuration, and the differential piston is moved forward through rods 170 and 172 to allow it to move within the pump cavity 218. Liquid propellant is sent back to the supply system 251.

[Brief description of drawings]

 FIG. 1 is a sectional view of an ignition mechanism according to an embodiment of the present invention. FIG. 2 is a diagram showing the ignition current, columnar pressure and combustion chamber pressure in the embodiment of FIG. 1 as a function of time. FIG. 3 is a cross-sectional view of an ignition mechanism incorporating a liquid propellant and a regenerative piston gun according to an embodiment of the present invention. 10, 52 ... Housing, 12 ... Main combustion chamber, 14 ... Ignition pre-combustion chamber, 16, 74 ... First conduit, 18 ... Orifice, 20, 78 ... Electrode, 36 ... Valve, 50 ... Barrel, 54 ... Gun cavity , 60 ... bullet, 64 ... play bottom, 82 ... inner cavity expansion (ignition pre-combustion chamber), 136 ... differential valve, 138 ... piston, 218 ... pump cavity, 220 ... combustion cavity (main combustion chamber).

Claims (6)

[Claims] 1. A liquid propellant gun comprising a main combustion chamber, an ignition pre-combustion chamber, a first cross-sectional area, two spaced electrodes and a suction port for the liquid propellant. An ignition pre-combustion chamber having a first conduit having a length to diameter ratio of greater than 1 and a second cross sectional area smaller than the first cross sectional area; A gun comprising an inlet opening to the ignition pre-combustion chamber and a first conduit having an outlet opening to the main combustion chamber. 2. The gun of claim 1, wherein the conduit outlet comprises an orifice having a third cross-sectional area less than the second cross-sectional area. 3. A gun according to claim 1, wherein a source (251) of high pressure liquid propellant, a second conduit (98) including valve means (259) and A second conduit connecting the source to the inlet (84) of the ignition pre-combustion chamber (82) and a control means for igniting a predetermined amount of liquid propellant from the source (251). A gun including a fuel chamber and control means coupled to the valve means for supplying to the first conduit. 4. The gun of claim 1, wherein the housing (52), the barrel (54), an annular valve sleeve (136) coaxial with the barrel, and an annular ring coaxial with the barrel. Differential area piston sleeve (138), wherein the sleeve and the piston sleeve define a pump cavity, and the piston sleeve and the housing define the main combustion chamber. A gun to collect. 5. The gun of claim 1, including a housing (52) having a breech (66) and a removable gun breech (64) disposed within the breech, A igniting pre-combustion chamber (82) and the first conduit (74) are arranged in the breech bolt. 6. The gun according to claim 5, further comprising a cam for controlling arrangement of the breech bolt and a cam for controlling electric current supply to the two electrodes.