US 2479888 A
Description (OCR text may contain errors)
Aug. 23, 1949. J w ETAL 2,479,888
CONTROLLING SYSTEM FOR REACTION MOTORS Filed July 6, 1943 3 Sheets-Sheet 1 JRMES H. WYLD LOVELL LAWRENCE JR- I INVENTORJ ATTORNEY Aug. 23, 1949. J. H. WYLD ETAL 2,479,883
CONTROLLING SYSTEM FOR REACTION MOTORS Filed July 6, 1943 3 Sheets-Sheet 2 O O 4 66 7 /3 O U 47 73 3 6 /6 JAHE5 H.WYLD LOVELL LAWRENCE JR.
INVENTORJ T RNEY Aug. 23, 1949. J. H. WYLD ET AL 2$479,388
CONTROLLING SYSTEM FOR REACTION MOTORS Filed July 6, 1945 S Sheets-Sheet a E I? Z6 '2 27 ox azw PEDIIC FIG -7 JAMES HWYLD LOVELL LAWRENCE .m.
I INVENTORS BY MW ATTO RN E! Patented Aug. 23, 1949 CONTROLLING SYSTEM FOR REACTION MOTORS James H. Wyld, Pompton Lakes, and Lovell Lawrence. Jr.. Paterson. N. J.. asslgnors to Reaction Motors Inc., Pompton Plains, N.
tion of New Jersey J., a corpora- Application July 6, i943, Serial No. 493,670 18 Claims. (Cl. 60-353) The present invention relates to mechanism for starting and controlling the operation of jet reaction or rocket motors producing a useful propulsive thrust by the recoil action of a high! velocity gas jet, particularly reaction motors actuated by the continuous combustion in a chamber of two or more liquid propellants fed under pressure to the motor from tanks; and it further relates to devices for ensuring a proper and safe sequence of controlling operations, and to means for indicatin the operating conditions to a pilot or operator at a point remote from the motor, and for transmitting control impulses from said control points to the reaction motor.
In operating a reaction motor of the liquid propellant type, several preliminary operations are performed before the motor can be started. As-
suming that pressure-tank feed is used, the vent valves on top of the propellant tanks are first closed, and gas under pressure is then fed to the tanks until the proper working feed pressure is built up. To start the motor the ignition device (such as a fuse or burner) is first turned on, and the main fuel valves are immediately afterward opened to permit flow of propellant from the tanks to the motor. At the completion of combustion, the reaction motor unit is shut down by performing the above operations in reverse order. It may also be necessary to vary the thrust over a wide range while the motor is working or to start and stop the latter several times in rapid succession.
Undesirable or dangerous conditions may arise if the above operations are not performed in cor rect order; thus, if the main propellant valves are turned on before the ignitor burner, the combustion chamber of the motor may fill up with a 'liquid explosive mixture which will violently explode when the ignitor is operated. Such accidents can be prevented either by operating the starting equipment from an automatic control which ensures a proper sequence of operations, or by providing suitable interlocking mechanisms which prevent the operator from manipulating the controls in incorrect order.
One of the purposes of the present invention is to provide means for such automatic operation and/or interlocking of the controls of a reaction motor, as will appear from a description of the invention.
A more specific object of the invention is to provide a starting control device for a reaction motor wherein an initial fiow of propellant fluid is fed to the motor and ignited, and in which in- 2 creased flow is prevented until ignition has been eifected.
A further object resides in the provision of automatic mechanism for varying the ratio of propellant flow to prevent overheating of the motor.
A still further object is to provide means for automatically purging the motor of unburned propellant upon stoppage of the operation of the motor.
Another object of the invention is to provide a control system for a reaction motor in which movement of a single operating lever will effect starting, operating and stopping of the motor operation.
Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example the principle of the invention and the best mode, which has been contemplated, of applying that principle.
In the drawings:
Fig. 1 is a diagrammatic representation of a control system in which the fluid propellant is fed to the motor under gas pressure.
Fig. 2 is a detail of a modified form of ignition burner for the motor.
Fig. 3 is a plan detail of the operating lever mechanism.
Fig. 4 is a detail of a further modified form of ignition burner.
Fig. 5 is a detail of a modified form of main valve operating mechanism.
Fig. 6 is a diagrammatic representation of a modified system, wherein the propellant is fed to the motor by pump pressure devices.
Fig. 7 is a detail of a modified form of pressure pump controlling mechanism.
A preferred form of the invention intended particularly for reaction motors used as auxiliary power for aircraft is shown in Fig. 1.
All the motor operations are controlled .by the handle I attached to bellcrank 2. Handle l is provided with a spring latch 26 working on a notched quadrant 21, permitting handle I to be set to any desired position on quadrant 21 and thereafter locked in position. Bellcrank 2 operates the hydraulic cylinder 3 through rod I. Displacement of the piston in cylinder 3 pumps fluid through pipe '5, causing the piston of the receiver cylinder 6 to rise. The piston rod 1 acts on lever 8, causing the eccentric disk 9 to revolve. The eccentric 9 has a close-fitting strap ill at tached to a connecting rod ll pivoted to a crosshead I 2 working in guides l3. As eccentric 9 revolves, the crosshead I2 is moved up or down.
upon the lift of these The motion of crosshead I2 acting on crossarm I8 determines the lift of the poppet valves I1 and I8. The stems of valves I1 and I8 are provided with flexible metallic bellows I4, I5, which permit motion of the valve stems but prevent leakage. These valves control the flow of the propellants from the pressure tanks I9 and 28 to the reaction motor 2|. Tank or reservoir 28 contains a suitable inflammable fluid (such as gasoline) while tank or reservoir I9 contains a fluid oxidizin agent (such as liquid oxygen). When liquid oxygen or any similar volatile material is used as an oxidizer, tank I9 is preferably provided with an outer jacket I41. The space between jacket I41 and tank I9 is evacuated or else packed with a heat insulating material, in order to insulate the tank from atmospheric heat and prevent evaporation of the oxygen.
Assuming a constant gas feed pressure in tanks I9 and 28, the rate of propellant feed, and thus the thrust of the reaction motor 2I will vary with the port area of valves I1 and I8, which depends valves; consequently, the setting of handle I will determine the motor thrust.
One form of reaction motor suited to the present method of control is shown in Fig. 1. It is of the self-cooled or regenerative type. The motor consists of an inner combustion chamber II9, inside which the combustion occurs. chamber I I9 is attached an expansion nozzle I28, through which the burning gases are ejected, thereby producing a propulsive thrust. To prevent overheating of the combustion chamber H9 and nozzle I28 by the intensely hot gases, an ex- 1 T ternal cooling jacket I2I and bafiie I22 are provided. These are separated from chamber IIS and nozzle I28 by a narrow annular passage I23. One of the liquid propellants is fed to the annular space outside bafiie I22, and flows through passage I23, thereby cooling nozzle I28 and chamber H9. The propellant is thereby heated and partly vaporized, and escapes into the interior of chamber II9 through a. ring of ports I24, mixing with the other propellant which is injected through ports I25 from manifold I48. The mixture is ignited by burner 52, as will be described later.
It is necessary to maintain a proper mixture proportion between the two propellants, which is accomplished by making the ports of valves I1 and I8 different in size. It is often desirable to have different mixture ratios according to whether the reaction motor is operating at full output or at reduced output. One method of accomplishing this is to provide metering orifices or constrictions 22 in the propellant pipes. The sizes of these orifices are adjusted to produce a correct mixture ratio when the valves I1 and I8 are fully open, the pressure drop through these valves being negligible compared to that through the orifices 22. The port areas of valves I1 and I8 are proportioned so as to produce the proper mixture ratio when the valves are nearly closed. the effect of the orifices 22 being negligible for this flow condition. At intermediate valve settings the mixture ratio varies between the limits set for the high-thrust and low-thrust conditions, depending on whether the effect of valves I1 and I8 or that of orifices 22 predominates.
It will be noted that the center of the eccentric disk 9 is so placed as to be nearly on "dead center when valves I1 and I8 are seated. This provides a very powerful leverage in order to open the valves against the full tank pressure when 4 starting the motor, and also in order to compress springs 24 when closing the valves. This arrangement also provides a slower rate of lift when the valves are slightly open than when they are open wide, thereby compensating for the disproportionately large flow rate at small openings (caused by the large pressure drop between the tanks and reaction motor when the latter is operating at reduced output).
Besides valves I1 and I8 and orifices 22, check valves 23 are provided in the propellant conduits or lines, in order to prevent combustible mixture from flowing back into the pipes or tanks if temporary pressure surges occur in motor 2I.
Since valves I1 and I8 act as shut-off valves as well as throttles, it is necessary for them to close very positively. For this reason, springs 24 are provided which keep the crossarm I5 pressed against the stops 25 attached to the stems of valves I1 and I8. These valves are adjusted to contact their seats slightly before crosshead I2 reaches the end of its stroke. Thereafter, the further downward motion of crosshead I2 causes crossarm I5 to compress springs 24, thus firmly holding valves I1 and I8 down on their seats. This arrangement ensures that both valves I1 and I8 will seat positively, regardless of whether or not one valve seats ahead of the other. Furthermore, as soon as both valves I1 and I8 are clear of their seats, they will lift or drop together in a definite position relative to each other, determined by stops 25. Stops 25 are adjustable along the valve stems by means of screws, nuts, or other devices, so as to permit proper adjustment of the seating of valves I1 and I8.
In order to indicate the thrust of the motor 2| to the pilot or operator of control handle I, a pressure gage 28 mounted near handle I is connected to the combustion chamber of motor 2I by a tube 29. It has been found that the thrust produced by a given reaction motor bears a deflnite relation to the pressure in the combustion chamber. Gage 28 can thus be calibrated to indicate motor thrust directly.
It has previously been mentioned that it is necessary to close the propellant tank vents, charge the tanks with pressure and start the ignition device before turning on the motor. These operations are carried out by an auxiliary control, operated by handle I. The bellcrank 2 carries a pawl 38, which engages a ratchet wheel 3| when the handle I is moved into its extreme lefthand (or closed) position (indicated by dotted lines). The ratchet 3I revolves a rotary switch 32, which alternately closes and opens an electrical circuit on successive strokes of pawl 38. The switch 32 is in series with a safety switch 33 and battery 34.
The control handle I and the lever 8 are provided with springs 35 and 36, whose tension is adjusted so as to maintain the levers I and 8 in a neutral position in which valves I1 and I8 are fully closed, and the piston of cylinder 8 is fully down, but pawl 38 does not engage hatchet 3|. To turn the ratchet, it is necessary to push handle I to the left against the pressure of spring 35, which is a short, stiff compression spring which comes in contact with handle I only when the latter is pushed to the extreme left, but which releases itself from handle I when the latter is pushed to the right.
The leftward motion of handle I also synchronizes cylinders 3 and 6 by opening a bypass valve 31 which temporarily connects pipe 5 with the oil reservoir 38, permitting oil to leak in or out of the pipe to compensate for any thermal expansion or leakage of the oil. This result can also be accomplished by means of a port 38 in the wall of the cylinder 3. This port is overrun by the piston or cylinder 3 when handle I is pushed to the limit of its stroke, allowing cylinder 3 to communicate directly with reservoir 38. It will be noted that leakage or breakage of pipe will cause spring 36 to close valves I1 and I8, thereby automatically shutting of! motor 2!.
Assuming that switch 32 is open and safety switch 33 is closed, pressing handle I to the extreme left causes pawl 3|) and ratchet 3| to revolve switch 32, closing the circuit through battery 34. This causes current to flow through the solenoids of valves 40, M, 42, 43, 44 and also the heater coil 45 and vibrator-type spark coil 46. The valves 40 and M then close, shutting oil the venting between the tanks and the external air. The valve 44 opens, supplying high pressure nitrogen gas (or other suitable inert gas, such as helium) from tank 41 through reducing valve 48, in which the pressure is reduced to a value suitable for the tank feed pressure. The gas is then fed from valve 48 through check valves 49 to the tanks I3 and 20. Simultaneously, valves 42 and 43 are opened, causing propellants to flow from tanks I9 and 28 through valves 42 and 43, metering orifices 50, and check valves 5| to the ignition burner 52, attached to reaction motor 2|. The propellants mix in the burner 52 and are ignited by the spark plug 53 operated by spark coil 46. It will be noted that the hydrocarbon propellant from tank 20 flows through the heating coil 45, which is electrically insulated from the rest of the piping by insulating bushings 54. Coil 45 is made of fine bore tubing of high electrical resistivity heated by the passage of current from battery 34. By thus combining the electric heating element with the heat-transfer surface of the coil, instantaneous heating and vaporization of the propellant is secured.
If liquid oxygen is used as the oxidizing propellant (as is frequently the case), it is found in practice that the small amount of oxygen required to operate the burner will automatically evaporate from liquid to gas in passing through the comparatively warm pipes between tank I9 and burner 52, arriving in the burner as oxygen gas. It is found experimentally that if both propellants are fed to the burner as vapors, as described above, the ease and reliability of igniting and burning them are improved.
A preferred construction of the ignition burner 52 is shown in detail in Fig. 2. The burner chamber I38 provided with air-cooling fins I38 screws into the end of the oxygen manifold I48 and clamps down the extension tube MI. The mixer head I42 screws into the opposite end of burner chamber I38. Mixer I 42 contains a central jet tube I43, through which oxygen gas is injected into chamber I38. Tube I43 is surrounded by an annular space I44, slightly constricted at its right hand or exit end, into which hydrocarbon vapor or liquid is fed from pipe I45. The constriction at the end of space I44 together with the tapered end of tube I43 causes the hydrocarbon jet from space I44 to impinge on the oxygen jet from tube I43, resulting in a highly atomized oxy-hydrocarbon mixture, which is ignited by the spark plug 53 and passes out through tube I4I into the combustion chamber II9 of reaction motor 2I, producing an intense flame which ignites the combustible mixture in chamber II! as soon as valves I1 and II are turned on. A thimble I46 is screwed into chamber I33 and contains a thermocouple 68, which is used as a, safety thermostatic interlock, as will be described later.
The burner chamber I38 is preferably composed of a metal of high thermal conductivity such as aluminum alloy or copper, to assist in dissipating the heat absorbed by the chamber walls. The extension tube I should be of a metal resistant to high temperatures to resist the action of the flame when first starting the burner. Once the main motor 2| is turned on, tube I is cooled by the flow of oxidizer through manifold I48 and ports I25.
Although a regenerative type of reaction motor is described in connection with this ignition burner and control apparatus in the present specification for purposes of illustration, the same burner and control devices can also be applied to any other type of continuous-combustion reaction motor, r quiring only minor changes in construction which do not affect the essential principles involved.
It is evidently dangerous to feed propellants from the main valves I1 and I8 into the reaction motor 2I before the burner 52 is properly lighted, since this may lead to an accumulation of unburned fuel in the motor chamber, causing a violent explosion when the ignition finally takes efiect. It is also undesirable to turn on the motor until full feed pressure has been built up in tanks I8 and 20. To prevent such premature operation of the motor, a locking bolt 54 (see Figs. 1 and 3) is provided attached to an iron rod 55a and the spring 55. The front face of bolt 54 is inclined (see Fig. 3) and consequently permits handle I to be moved past the bolt towards the left in order to start the motor, but prevents the operator from returning handle I to the right and opening valves I1 and I8 until bolt 54 is withdrawn, which is accomplished at the proper time by the solenoid 51. This solenoid 51 is in series with battery 34, contacts of sensitive relay 58, and pressure switches 58. Relay 58 is energized by the action of the thermocouple 68 attached to burner 52, as soon as the burner is heated by the beginning of combustion within it.
An alternative method of providing for releasing a lever I after burner 52 is lighted is shown in Fig. 4. This device consists of bulb 55, flexible metal bellows I84, and insulated contact I85. Bulb 55 contains a volatile liquid which is evaporated by the heat of burner 52. The resulting vapor pressure in bellows I84 causes the latter to expand, closing contact I05, which is in series with switches 59 and solenoid 51. Switches 58 are adjusted to close as soon as the tank pressures reach the proper value. Solenoid 51 then operates, withdrawing bolt 54 and permitting the operator to move handle I to the right and start the motor. The operator is notified of the operation of solenoid 51 by the signal light 62 connected in parallel with solenoid 51. A hand knob 5| (Fig. 3) permits bolt 54 to be released manually for testing the equipment or to release the solenoid in case of sticking.
It is found in practice that the operation of the ignition burner 52 results in a considerable gas pressure within the combustion space of chamber I38. It is also apparent that the operation of burner 52 will be indicated to the operator by a rise in the reading of pressure gage 28,
the latter being connected to burner 52 as shown in Figs. 1, 2 and 4.
.leased and returns a ,under the action of/ spring 35, operating pawl To stop the motor, the handle I is moved to the left to the full line position of Fig. 1 and valves I1 and I8 close. The burner 52 continues to operate, and pressure is left on in tanks l9 and 20. Therefore, the motor can be restarted simply by moving handle I back to the right and reopening the propellant valves I1 and I8. To shut down the equipment completely, handle I is moved to the extreme left against the pressure of spring permitt ng pawl 38 to engage the next tooth on ratchet 3|. Handle I is then rehort distance to the right 38 and ratchet 3| and opening the circuit through switch 32, thus venting the tanks I9 and 20 through valves and 4|, which open automatically when the electric current in their solenoids is cut off. Valve 4| is connected to the motor 2| through pipe 83 and check valve 64, thus causing the pressure gas from tank 28 to blow off through motor 2| and purge out any lingering explosive charge in the motor chamber.
The opening of switch 32 also closes the valve 44, shutting off the flow of pressure gas from tank 41. Simultaneously, the flow of propellants to burner'52 is stopped by the closing of valves 42 and 43, and heater and spark coil 48 are also shut off.
The switch 32 can be operated manually by means of knob 65. Safety switch 33 can also be used to open the circuit and return the various controls to the stopped position.
When operating reaction motor 2| for prolonged periods at reduced output, there is sometimes a tendency for the motor to overheat, owing to the reduced supply of coolant to space I23. Valves I1 and I8 are adjusted to supply a "rich mixture (that is, a high ratio of hydrocarbon to oxidizer) atlower output, to compensate for this effect. It is also desirable to have a safety device which automatically supplies more coolant if the motor 2| becomes unduly hot. This may be accomplished by the use of a thermocouple I26 attached to the liner chamber H9 or some other highly heated part of the motor 2|. Excessive temperature causes thermocouple I26 to close the sensitive relay I21, which thereby opens the solenoid by-pass valve I28, permitting the hydrocarbon propellant to fiow directly from tank 28 to motor 2|, thus increasing the flow of coolant. As the supply of oxidizer from tank I9 is not affected by this operation, the motor thrust will not be appreciably increased.
Experience has shown that it is undesirable to permit the liquid level in either tank I9 or tank 2|) to decrease below a certain limit while motor 2 I is in operation, since there is then a tendency to draw bubbles of gas into the tank outlets, resulting in objectionable oscillations or detonations in the motor combusion. To obviate such a condition. floats I29 and I38 are provided. operating switch elements I3I and I32 installed in the walls of tanks I9 and 20. Switches I 3| and I32 are connected in series, and are normally closed when the floats I29 and I38 are raised by the liouid in the tanks. One side of switches I3I and I32 is connected to switch 32. The other side leads to the windings of solenoid valves I33 and I34 (which are held open when the current is on, but other-wise close automatically), and thence back to the return lead to battery 34. Any fall in liquid level below the level of the float in either tank I9 or 28 will thus cause one of the switches I3I and I32 to open, thereby closing the shut-oil valves I33 and I34 and stopping the motor. As the valves are in series with switches 32 and 33, they will also be closed by the opening of either of these switches, or by any other interruption in the electric current supply, thus providing an additional safety feature. Since valves I1 and I8 are purely mechanical in either operation, they enable the motor to be shut ofl entirely independently of the electrical valves I33 and I34. Conversely, valves I33 and I34 act as safety devices in cases of failure of the throttle valves I1 and I8.
It is also desirable in certain cases to apply a pneumatic servo mechanism to cylinder 8, actuated by auxiliary nitrogen gas pressure (see Fig. 5). Handle moves bellcrank 2 and the piston of cylinder 3, thus moving the piston of cylinder 8 by the hydraulic pressure in pipe 5. The piston rod I operates a slide valve 86, moving in the valve chest 61. Pressure is supplied to the center of valve chest 61 through a flexible tube 68 leading to the reducing valve 48. Motion of valve 85 upward uncovers the port 18, causing gas pressure to be fed to the upper end of cylinder 1| while the lower end of the cylinder is permitted to exhaust through port 69 and the open end of valve chest 61. The cylinder 1| then slides upward on the rod 13 (piston 12 and rod 13 remaining fixed). This action revolves the eccentric 9 by means of rod 14 and lever 8, thus operating crosshead I2 which controls the main propellant valves, as described previously. The motion of cylinder 1| closes the inlet port 18, stopping further motion of the cylinder 1| till valve 68 is moved to a new position. The motion of cylinder 1| thus closely follows that of valve 68, and hence of handle I. Handle I, however, need supply only enough force to actuate valve 68, instead of revolving eccentric 9 directly. This arrangement is desirable if valves I1 and I8 are of such a size as to require an ob- Jectionably large control force if operated directly from cylinder 6. It should also be noted that valves I1 and I8 cannot be opened until pressure is fed to the reducing valve 48 by the opening of valve 44, since the compression spring 36 main- 45 tains eccentric 9 in the closed position until pressure is supplied to cylinder 1|. Since valve 48 also supplies tanks I3 and 2|), valves I1 and I8 will-not open when pressure is not being fed to these tanks, thus providing a further safety 50 feature.
In cases where the eccentric 9 and handle I are not too far apart, the hydraulic system (comprising cylinders 3 and 8 and pipe 5, together with oil reservoir 38 and valve 31) may be dispensed with, and the handle I can be connected to eccentric 9 by a torque shaft, a push rod, flexible cables, or other direct mechanical connection. The hydraulic system, however, affords a more conven lent, flexible, and readily installed control system 80 if the reaction motor equipment is mounted a considerable distance away from the pilot, as is usually the case.
For certain applications of reaction motors, it is advantageous to feed the propellants to the reaction motor by means of a pump system, the tanks being maintained at atmospheric pressure. This is particularly useful on military aircraft, since the propellant tanks and nitrogen gas tank used in a gas-pressure feed system offer a very vulnerable target to enemy gunfire during the period in which the reaction motor is in operation, with full pressure in all the tanks. On the other hand, a pump system requires only a few parts of the system to operate at high pressure and a violent explosion or fire is very unlikely in ease of damage to the equipment by gunfire or otherwise. The use of pumps also enables higher motor pressures to be used without an unreasonable increase in weight, since it is only necessary to increase the weight of the motor, pumps, and drive motor to reach high pressures with pump feed, while with gas pressure feed it is necessary to increase the weight of the whole tank system. The use of high motor pressure results in greater thermal efliciency, as is well known in the prior art of reaction motor design. An advantageous method of pumpingthe propellants to the motor is the use of centrifugal pumps or else so-called rotary pumps (such as gear pumps or screw pumps) operated at high rotational speed, and driven by a small turbine operated by the gas pressure in the reaction motor combustion chamher. A control system suitable for such an installation is shown in Fig. 6.
Referring to Fig. 6, the propellants are contained in tanks I9 and 20, which are of much lighter construction than the corresponding tanks used in the previously described gas-pressure feed system, since they are maintained at atmospheric pressure at all times. The filling caps 14 on top of the tanks are provided with check valves 15, which are so adjusted as to permit atmospheric air to flow into the tank readily, but to flow out only slowly. In this way, the tank contents are prevented from spilling out owing to oscillations or vibration of the tank, while at the same time the outflow of the propellants through the bottom connections will not cause a partial vacuum which would interfere with the flow. The propellants are fed to the motor by pumps 16 and 11, which may conveniently be centrifugal r positive-displacement rotary pumps, or multi-cylinder reciprocating pumps. If the propellant in tank I9 is liquid oxygen or other cold and highly volatile fluid, the pump 16 may advantageously be placed inside tank I9 mounted on a removable flanged plate 18. In this way, the pump 19 is brought to the same temperature as the propellant before being put in operation, avoiding distortion of the parts by thermal contraction and preventing frosting-up of the pump, since it is surrounded by the propellant. The pump drive shaft 19 passes through a stufling box 82, which is mounted on an extension tube 80 with radiating fins 8| which absorb heat from the atmosphere and prevent the packing in stufling box 82 from freezing.
Pumps 16 and 11 are driven by the worm wheel 93, which in turn is driven by worm 84 on shaft 85. When friction clutch 86 is engaged by the operation of shifter fork 81 by solenoid 88, shaft 85 is connected with turbine wheel 99, which is revolved by a gas jet escaping from nozzle 90. The necessary gas pressure is furnished by the reaction motor 2|, through the pipe 9|; the gas flows through the tubes 92 of intercooler 93, which is cooled by the fiow of propellant from pump 11 to reaction motor 2| through jacket of intercooler 93. This arrangement is provided to cool the intensely hot motor gas, which would otherwise damage the blading of the turbine 89. Further cooling of the gas is provided by the desuperheater tube I 09, which has a constricted throat I01 into which opens a jet tube I08 connected to a small water tank I09. The clearance space of tank- I09 is connected to chamber IIO ahead of throat I01. The flow of gas through throat I01 sucks water from tank I09 through jet I08, in the form of flne spray, which rapidly vaporizes into steam, thus cooling the gas from pipe 9| and also increasing the volume of gas.
The speed of turbine 89 is regulated by the throttle valve 94, which is controlled through bellcrank 91 by the centrifugal governor 95 driven by reduction gears I02. Governor 95 throttles down the gas supply if the speed of the pumps becomes excessive, maintaining the speed at a definite value determined by the tension of compression spring 99,.which opposes the action of the governor flyweights. The tension of spring 96 can be varied by the motion of the piston of hydraulic cylinder 9. The hydraulic pressure operating cylinder 5 is supplied through pipe 5 from cylinder 3, the piston of which is moved by handle I and bellcrank 2. The position of handle I thus controls the motor thrust by regulating the setting of governor spring 96, and thus determining the speed of turbine 89 and pumps 16 and 11. The latch 29 and sector 21 maintain handle I in whatever position it is set.
It is necessary to provide an auxiliary source of power for starting the turbine and pumps before pressure begins to build up in the reaction motor 2|. This is accomplished by bringing the turbine wheel 89 up to a, very high speed with friction clutch 89 disengaged and then engaging clutch 86, causing wheel 89 to rotate pumps 16 and 11 by its inertia or flywheel effect. The propellants are thus pumped into the reaction motor 2|, where they are ignited by burner 52 and rapidly build up pressure which thereafter maintains turbine 89 in operation. The turbine wheel 89 is brought up to speed by the electric starting motor 99, which revolves wheel 89 through the speed-increasing gears 99 and the overruning clutch I00. (Clutch I00 is shown diagrammatically as a jaw clutch, but in practice it preferably takes the form of a wedging-roller clutch or other suitable friction device which looks the clutch if torque is applied in one direction but loosens it if the torque reverses.)
A centrifugal switch I 0| is operated by governor 95 through bellcrank 91. The switch IOI has two separate sets of contacts. The left hand set is in circuit with motor 99, shutting off the electric current to motor 98 whenever the speed of wheel 99 exceeds a certain maximum determined by the governor spring 96. The speed of wheel 89 is thus prevented from becoming excessive while running the wheel up to speed.
To start up the motor, handle I is pushed past its neutral position, against the pressure of spring 35, to the extreme left-hand position indicated in dotted lines. This actuates the synchronizing valve 31, thus synchronizing the cylinders 3 and 6 in the manner previously described. In addition, bellcrank 2 closes the upper contact of switch II2, thus energizing the motor 98 and revolving the turbine wheel 89. After the latter reaches a speed determined by the setting of governor 95 and switch IOI, its revolution rate remains constant. The switch II2 also supplies current to the left-hand half of the winding of relay II3, which closes the circuit through the solenoid valves 42 and 43. The opening of valve 42 permits oxygen gas from pressure tank H4 and reducing valve II5 to flow to burner 52, while valve 43 similarly feeds propane, hydrogen, or other inflammable gas from pressure tank H6 and reducing valve 1. The gases mix in burner 52 and are ignited by spark plug 53 actuated by spark coil 49 shunted across the solenoids of valves 42 and 43.
When the ignition burner is properly lighted, the relay 58 is closed by the action of thermocouple 50 attached to burner 52 (or by some equivalent thermostatic control). The contacts of relay 58 are in series with the right hand pair of contacts of the governor switch IN. The latter are arranged to close at a governor speed slightly below that which opens the left-hand pair of contacts, so that when the wheel 68 is running at its rated starting speed the righthand contacts of switch IIlI remain continuously closed. If at the same time relay 58 is closed, the circuit is completed through solenoid 51, withdrawing the safety bolt 54. At the same time, the signal light 62 indicates to the operator that wheel 89 is up to full speed and burner 52 is lighted, and that the pumps 16 and 11 can now be started.
Handle I is now moved to the right (as indicated by the right hand dotted lines) This opens the circuit through the upper contacts of switch H2, thus shutting off the starting motor 88. The wheel 89 continues to revolve owing to its momentum, while the over-running clutch I88 effectively disconnects motor 98 from wheel 88. The motion of handle I then closes the lower contacts of switch H2, energizing the solenoid 88 and engaging clutch 86, thus starting pumps I6 and H, which begin to feed the propellants to the motor 2|, where they are ignited by burner 52. The motor II is then in full operation, and is thereafter controlled by governor 85, as previously described.
It will be noted that the operation of moving switch H2 from the starting to the running position shifts the current flow in relay H3 from the left half of the winding to the right half. While handle I is passing momentarily through its neutral or "ofi position, both contacts of switch H2 are open and there is no current in the coil of relay H3. To prevent the relay H3 from momentarily opening and thus shutting off burner 52, a copper slug or short-circuited winding H8 is provided, whose self-inductance causes a delay in the opening of relay H3 until the circuit is reclosed through switch H2. An equivalent delay device (such as a dashpot) may replace winding H8.
To shut off the motor 2|, the handle I is returned to its neutral position. This opens all the circuits, thus shutting off the igniter burner 52 and spark coil 46, and also opening clutch 86, stopping the pumps 16 and I1 and shutting off motor 2|.
Spring-loaded check valves I83 and I I I are provided in the fuel lines between tanks I9, 28 and the motor 2|. These valves are so adjusted as to remain shut under the hydrostatic head caused by the fuel in the tanks, but they open freely under the feed pressure developed by the pumps. The purpose of these valves is to prevent fuel from leaking through the pumps I6 and 11 into the motor 2I while the pumps are disconnected from the turbine wheel 89.
An alternate method for starting pumps 16 and H which is particularly suitable for centrifugal pumps is shown in Fig. 'l. The friction clutch 86 is replaced by a permanently engaged, spring-loaded friction clutch I31, which is adjusted to slip if the torque exceeds a certain maximum, in order to protect the transmission shafts and gearing against excessive shocks resulting from variations in the pumping pressure, owing to changes in the combustion rate in the motor or other causes. Check valves I83 and III are replaced by the solenoid valves I35 and I36, which are connected to the lower contacts of switch I I2, and consequently are opened when handle I is moved to the right into the operating position. When starting the pump turbine 89, the pumps I6 and 11 (which are of the centrifugal type) revolve with wheel 89, producing a pressure head in the pipes but delivering no fluid until valves I35 and I36 are subsequently opened when handle I is moved to the starting position. If the pumps 18 and I1 are of the positive-displacement type, valves I35 and I36 should be installed at the inlets to pumps I6 and 11 (instead of the exhausts, as shown in Fig.7). In this case the pump rotors run dry until the valves I35 and I36 are opened. v
When high-speed centrifugal pumps are used, the gears 83 and 84 may be dispensed with, and the shaft 85 connected directly to shaft 19. The pumps I6 and I1 then run at the same speed as turbine 89.
While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a single modification, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. It is the intention therefore to be limited only as indicated by the scope of the following claims.
What is claimed is:
1. In a system of the class described, a reaction motor having a main combustion chamber and a firing chamber, a pair of reservoirs each containing a liquid propellant, means for creating pressure within said reservoir, pressure responsive means for each reservoir, a conduit between each reservoir and said combustion chamber, a further conduit between each reservoir and said firing chamber, a normally closed valve in each conduit, devices for causing opening of the valves in the firing chamber conduits and for concurrently rendering said pressure creating means effective, further devices for opening the valves in the combustion chamber conduits to enable propellant to flow therethrough, said first and second named devices being operable in succession, an ignition device in said firing chamber operative to ignite the propellants in said firing chamber, and means responsive jointly to the heat of combustion in said firing chamber and to said pressure responsive means, for controlling the operation of said further devices.
2. In a system of the class described, a reaction motor having a combustion chamber, a pair of reservoirs each containing a liouid propellant, means for creating pressure within said reservoir, pressure responsive means for each reservoir, a main conduit between each reservoir and said combustion chamber, an auxiliary conduit between each reservoir and said combustion chamber, a normally closed valve in each conduit, devices for causing opening of the valves in the auxiliary conduits and for concurrently rendering said pressure creating means effective, further devices for opening the valves in the main conduits, said first and second named devices being operable in succession, an ignition device in said combustion chamber operative to ignite the propellants fed to the chamber through said auxiliary conduits, and means responsive jointly to the heat 'of combustion of said ignited propellants and to said pressure responsive means for controlling the operation of said further devices.
3. In a system of the class described, a reaction motor having a combustion chamber. a reservoir containing a liquid propellant, means for creating pressure within said reservoir, pressure responsive means for the reservoir, 8. main conduit and an auxiliary conduit between said reservoir and said combustion chamber, a normally closed valve in each conduit, means for opening the valve in the auxiliary conduit to feed propellant to said chamber, and for concurrently rendering said pressure creating means effective, further means for opening the valve in the main conduit, said first and second named means being operable in succession, an ignition device in said combustion chamber operative to ignite the propellant fed to the chamber through said auxiliary conduit, and means responsive jointly to the heat of combustion of said ignited propellant and to said pressure responsive means for controlling the operation of said further means.
4. In a system of the class described, a reaction motor having a combustion chamber, a reservoir containing a liquid propellant, means for creating pressure within said reservoir, pressure re-- sponsive means for the reservoir, a main conduit and an auxiliary conduit between said reservoir and said combustion chamber, means for causing propellant to flow from the reservoir to said chamber through said auxiliary conduit and for concurrently rendering said pressure creating means efiective, an ignition device in said combustion chamber operative to ignite the propellant fed thereto, normally ineffective operating means for causing propellant. to flow from the reservoir to the chamber through said main conduit, and means rendered effective upon the occurrence of combustion in said chamber and the action of said pressure responsive means for rendering said operating means effective.
5. In a system of the class described, a reaction motor having a combustion chamber, a reservoir containing liquid propellant, a conduit between said chamber and reservoir, a valve in said conduit, means for creating pressure in said reservoir, a device for concurrently opening said valve and rendering said pressure creating means effective to feed propellant under pressure to said chamber, means for causing combustion of the propellant in said chamber, normally ineffective operating means for causing feeding of additional propellant to said chamber, means responsive to the pressure created in said reservoir, temperature responsive means in said chamber, and means jointly controlled by said temperature responsive means and by said pressure responsive means for rendering said operating means effective. 6. In a system of the class described, a reaction motor having a combustion chamber, a reservoir containing liquid propellant, a conduit between said chamber and reservoir, a valve in said conduit, means for creating pressure in said reservoir, a device for concurrently opening said valve and rendering said pressure creating means effective to feed propellant under pressure to said chamber, means for causing combustion of the propellant in said chamber, normally inefi'ective means for controlling the feeding of additional propellant to said chamber and means responsive jointly to the heat of combustion in said chamber and to the pressure in said reservoir for rendering said normally ineflective means eifective.
7. In a control system of the class described, a reservoir containing liquid propellant, a reaction motor having a firing chamber and a combustion chamber, means for creating pressure in said reservoir, a main conduit between said reservoir and said combustion chamber, an auxiliary conduit between said reservoir and said firing chamber, ignition means in said flrlng chamber, a control lever movable from a neutral position to a starting position and then to an operating position, means normally preventing movement to said operating position, means concurrently controlled by the lever when moved to its starting position for rendering said pressure creating means and said ignition means efiective and for causing propellant to flow through said auxiliary conduit, whereby combustion will take place in the chambers of said motor, means for maintaining said last named means continuously efiective, means responsive to said heat of combustion for disabling said preventing means whereby said lever may be moved to its operating position, and means controlled by the lever when moved to its operating position for causing propellant to feed to the combustion chamber through said main conduits, the heat generated by the propellant fed through said auxiliary conduit causing combustion of the propellant subsequently fed through the main conduit.
8. The invention set forth in claim 7 in which movement of the lever from its operating position back to its neutral position will operate the last named means to disable feeding of propellant through said main conduit and in which further means is provided and responsive a second movement of the lever to its starting position to disable feeding of propellant through said auxiliary conduit.
9. In a control system of the class described, a reservoir containing liquid propellant, a reaction motor having a firing chamber and a combustion chamber, means for creating pressure in said reservoir, a main conduit between said reservoir and said combustion chamber, an auxiliary conduit between said reservoir and said firing chamber, ignition means in said firing chamber, a control lever movable from a neutral position to a starting position and then to an operating position, means normally preventing movement to said operating position, means controlled by the lever when moved to its starting position for rendering said pressure creating means and said ignition means effective and for causing propellant to flow through said auxiliary conduit whereby combustion will take place in the chamber of said motor, said last named means being controlled by the lever upon movement of the lever from its starting position to its neutral position and then back to its starting position to disable the pressure creating, ignition and propellant flow means.
10. The invention set forth in claim 7 in which the pressure creating means comprises means for introducing gas under pressure into said reservoir, and means controlled by the lever upon movement of the lever from its operating position back to its neutral position for causing the gas in said reservoir to be directed into the combustion chamber to purge the same of propellant.
11. In a control system for a reaction motor, a reservoir containing liquid propellant, a reaction motor having a combustion chamber, means for creating pressure in said reservoir, 8. main conduit between said reservoir and said chamber, an auxiliary conduit between said reservoir and said chamber, ignition means in said chamber, a control device adjustable to represent neutral, starting and operating conditions, in successive order, means normally preventing adjustment thereof to represent the operating condition, means concurrently controlled by said control device when adjusted to represent the starting condition for rendering said pressure creating means and said ignition means effective and for causing propellant to flow through said auxiliary conduit, whereby combustion will take place in the chamber of said motor, means for maintaining said last named means continuously effective, means effective upon the occurrence of combustion in said chamber for disabling said preventing means whereby said control device may be adjusted to represent the operating condition, and means controlled by the device when so adjusted for causing propellant to feed to the chamber through said main conduit.
12. In a control system for a reaction motor, a reservoir containing liquid propellant, a. reaction motor having a combustion chamber, means for creating pressure in said reservoir, ignition means for igniting propellant in said chamber, a control device adjustable to represent a neutral and a starting condition, means controlled by said control device when adjusted to represent the starting condition for rendering said pressure creating means and said ignition means effective and for causing propellant to flow from said reservoir to said combustion chamber whereby combustion will take place in the chamber of said motor, means for disabling said last named means, and means effective upon said disabling for venting the created pressure in said reservoir through said combustion chamber to purge the same.
13. In a control system for a reaction motor, a reservoir containing a liquid propellant, a' reaction motor having a combustion chamber, means for creating pressure in said reservoir, ignition means for igniting propellant in said chamber, a control device adjustable to represent a neutral and a starting condition, electrical means controlled by said control device when adjusted to represent the starting condition for rendering said pressure creating and said ignition means efiective and for causing propellant to flow from said reservoir to said combustion chamber, which combustion will take place in the chamber of said motor, means effective upon failure of current in said electrical means for disabling said ignition and flow means, and means responsive upon such failure of current for directing the created pressure through the combustion chamber to purge the same.
14. In a control system for a reaction motor, a reservoir containing a propellant, a reaction motor having a combustion chamber, a source of gas under pressure, a control device adjustable to represent a neutral and a starting condition, means controlled by said device when adjusted to represent the starting condition for causing propellant to flow from the reservoir to the combustion chamber, means for causing interruption of said flow, and means controlled by said interrupting means upon said interruption for directing gas from said pressuresource through the combustion'chamber to purge the same.
15. In a control system for a reaction motor, a reservoir containing a propellant, a reaction motor having a combustion chamber, a source 01' gas under pressure, operator controlled means for causing propellant to flow from the reservoir to said chamber and for igniting said propellant in the chamber, means at the will of the operator for interrupting said flow, and means controlled by said interrupting means for directing gas from said pressure source through the chamber to purge the same.
16. In a system of the class described, a reaction motor having a combustion chamber, a normally ineffective fuel pumping mechanism for pumping fuel to said chamber, separate means for feeding a charge of fuel to the combustion chamber and igniting said charge, means effective when said charge is ignited for rendering the pumping mechanism effective, and further means effective when the charge is ignited for causing the products of the combustion to operate the pumping mechanism.
17. The invention set forth in claim 16 in which the last named means comprises a turbine driven by the gases of combustion and includes devices for adding water to the gases before they operate the turbine.
18. In a system of the class'described, a reaction motor having a combustion chamber, a fuel reservoir, pumping mechanism for pumping fuel from the reservoir to the combustion cham. her, a driving turbine for said pumping mechanism, connecting means therebetween, normally inefiective operating means therefor, control means for driving the turbine, sending a charge of fuel to the chamber and igniting the same, means responsive to the heat of combustion of the ignited propellant, means controlled jointly by the turbine when-it reaches a predetermined speed and to said responsive means when combustion occurs in the chamber for rendering said operating means effective, whereby the same may connect the turbine to the pump to feed further fuel to the motor.
JAMES H. WYLD. LOVELL LAWRENCE, JR.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 1,237,862 Bintlifl Aug. 21, 1917 1,596,836 Hoff Aug. 17, 1928 1,879,186 Goddard Sept. 27, 1932 2,072,384 Schmidt Mar. 2, 1937 2,271,903 Stuckenholt Feb. 3, 1942 2,280,835 Lysholm Apr. 28, 1942 2,325,619 Lysholm Aug. 3, 1943 2,397,657 Goddard Apr. 2, 1946 FOREIGN PATENTS Number Country Date 522,163 France Mar. 22, 1921 157,231 Switzerland Dec. 1, 1932