Background of the Invention
1. Field of the Invention
This invention relates to a sleeve valve to be used in conjunction with a pulsed gas generator, especially a pulsed rocket engine for underwater acoustic applications.
2. Description of the Prior Art
It has been proposed that the pulsed rocket engine, designated the "Hippe", produced by the Rockwell International Corporation, Canoga Park, Calif., be utilized as an underwater sonic source. One version of this engine is described in U.S. Pat. No. 4,258,546, issued Mar. 31, 1981 to H. S. Stratton. The engine can deliver a 3-10 msec pulse of exhaust gas at chosen pressures up to about 15,000 psi. However, it has been found that a pulse of pressure enduring for such a length of time tends to be absorbed by the large volume of water into which the pulse is delivered rather than to generate a useful acoustic wave, i.e., that the acoustic pressure wave does not attain as high an amplitude as it would with a shorter delivery time.
Objects of the Invention
An object of the invention is to maximize the acoustic pressure of a pulsed rocket engine which delivers its chamber output gas into an aqueous environment.
Another object is to allow engine combustion in a pulsed rocket engine which discharges into an aqueous environment to occur without the presence of water during pressure buildup.
A further object is to provide rapid discharge of a desired portion of the total gas volume at a desired pressure.
Yet another object is to rapidly discharge a disired portion of the total gas volume of a pulsed rocket engine into an aqueous medium at a desired pressure.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing.
Summary of the Invention
The objects and advantages of the present invention are achieved by connecting a sleeve valve to the exhaust end of the combustion chamber of a pulsed rocket engine, preferably the Hippe engine. The valve operates to keep the outlet ports closed in the chamber wall of the valve by means of a spring-biased sleeve while the propellants fed to the engine's combustion chamber are burned and then to open the ports when a predetermined pressure is reached in the combustion chamber, allowing a sudden pulse of gas at the predetermined pressure and volume to exit from the valve.
Brief Description of the Drawings
The single FIGURE is an axial cross-section of a sleeve valve, in accordance with the invention, shown schematically connected to a pulsed gas generator.
The same elements or parts throughout the figures of the drawing are designated by the same reference characters.
Detailed Description of the Invention
The FIGURE provides an axial cross-sectional view of a sleeve valve 10 and a schematic view of a pulsed rocket engine, used as the gas generator 12 to the output end of which the valve 10 is coupled through a flange coupler 14.
The gas generator is, preferably, a Hippe engine which is a product of the Rockwell International Corporation, Canoga Park, Calif., an embodiment of which is described in U.S. Pat. No. 4,258,546, issued Mar. 31, 1981, to Harold S. Stratton, which patent is incorporated herein by reference. Gas is generated by this engine in repetitive pulses, generally about 10 msecs. in duration, at a variable rate of up to about 60 pps. The underwater frequency band of the pulser is about 25-250 Hz. The output thrust of the engine can be as much as 10,000 lbs. with a chamber pressure of up to 30,000 psia or more.
The sleeve valve 10 is essentially tubular in construction, although it may have other shapes, such as rectangular, in the direction transverse to the longitudinal axis. A central chamber 16 is formed by a tubular chamber wall 18 and a chamber end plug 20 which closes off the end of the chamber 16. A bore 22 extends partially into the plug 20 from the downstream (with reference to the flow of gas from the gas generator 12) end.
A sleeve 24 fits over the outside of the chamber wall 18. The sleeve 24 has a pair of opening ports 26, 28 in it and can be moved upstream as far as a shoulder 30 in the chamber wall 18. A spring 32 sits in a space 34 between the downstream side of the outside of the chamber wall 18 and a cylinder 36 which fits snugly over the outside of the chamber walls 18. The spring 32 exerts a downstream bias force on the sleeve 24 keeping the sleeve ports 26, 28 closed off from a pair of ports 38, 40 in the chamber wall 18.
A tubular cap 42 is placed around the downstream end of the plug 20 and fastened to the end of the chamber wall 18 by means of bolts 44.
The contact areas between the cap 42, the sleeve 24, the chamber wall 18 and the plug 20 are sealed against flow of gas or outside fluid by means of a plurality of seals such as O-rings, seal rings, channel seals, etc., as shown by elements 46, 48 and 50.
A channel 52 connects the actuation port 22 with the downstream end of the space between the cap 42 and the chamber wall 18, within which space the sleeve 24 slides.
A pressure sensor 54 is placed in the chamber wall 16, although it may be placed within the combustion chamber wall of the Hippe engine 12. The sensor 54 is electrically connected to control a gas source 56 the output of which is fed into the actuation port 22 in the plug 20.
In operation, the Hippe engine is fired and the gas output fills the chamber 16 of the sleeve valve 10. The pressure therein is sensed by the pressure sensor 54 and when the pressure reaches a preselected level (e.g., 6000 psia), a signal is sent to the gas source 56 commanding it to release gas into the actuation port 22. This gas has a pressure acting against the sleeve area to create a force sufficiently higher than the spring force to quickly move the sleeve 24 upstream to the chamber shoulder 30. This action also axially aligns the sleeve ports 26, 28 with the chamber-wall ports 38, 40, respectively, allowing the gas in the chamber 16 to suddenly discharge to the environment surrounding the sleeve valve 10.
The fast-acting sleeve valve described herein, among other things:
(1) allows engine combustion to occur without the presence of water during initial pressure build-up, a factor that contributes to achieving high pressure from the engine combustion chamber, since the presence of water causes slow ignition by quenching the combustion process.
(2) eliminates the time required to build chamber pressure (rise time of the gas pulse) since the output pulse is released from the sleeve valve after the preselected pressure and volume is reached; and
(3) provides a rapid discharge of the predetermined gas volume at a desired pressure.
Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.