US 3515518 A
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June 2, 1970 A. M. HALSTEAD ETAL 3,515,518
I COOLANT FOR PROPELLANT ACTUATED GAS GENERATOR Filed Aug. 23, 1967 INVENTORS. ARTHUR M. HALSTEAD, DECEASED BY ALBERTA MHALSTEAQADMINISTRATRIX OSYP NIMYLOW CZ BY 7n a Q '1 f g 'z I ATORNYS United States Patent Office US. Cl. 23-281 4 Claims ABSTRACT OF THE DISCLOSURE A propellant actuated gas generator having a metallic carbonyl coolant such as molybdenum-hexacarbonyl in a forward chamber and surrounding a dispersing tube for developing substantially permanent or sustaining gas pressure for inflating purposes. A first filter bed is positioned in the rearward chamber forward of the propellant and a second filter bed is located in the forward chamber forwardly of the metallic carbonyl coolant.
This invention relates to gas generators and, more particularly is a gas generator capable of developing pressure for inflating purposes.
In propellant actuated gas generators for inflating tanks, life rafts, etc., coolants heretofore employed such as salts of ammonium often contain water of crystallization. Upon heating they partially sublime and partially decompose endothermically to ammonia gas, carbon dioxide gas and water vapor, both gases being soluble in water. During initial inflation, the gases fill the tank, but only establish a temporary pressure prior to being cooled to ambient temperature whereupon the sublimed coolant solidifies, and along with the gases dissolve in the existing water condensation, all of which adversely results in a considerably reduced tank or vessel pressure.
Accordingly, one of the objects of the invention is to provide an eflicient gas generator capable of developing substantially permanent or sustaining gas pressure for inflating purposes.
Another object is to use in a gas generator a coolant which upon endothermic decomposition provides a permanent gas which is not soluble in water.
These and other objects, features and advantages will become more apparent from the following description and accompanying drawing which is a longitudinal sectional view of a preferred gas generating arrangement embodying the principles of the invention.
In the drawing the propellant actuated gas generator has a substantially hollow, cylindrical main body 11 with a laterally extending partitioning wall 12 positioned substantially mid-length thereof and defining a rearward chamber 13 containing a predetermined form of low temperature, slow burning propellant 14 and a charcoal filter bed 15 positioned forwardly of the propellant and adjacent the wall 12, as well as a forward chamber 16 that contains a preferred form of coolant 17 and a second filter bed 18 of aluminum oxide stones adjacent the forward end wall 19. Wall 19 has an appropriately apertured central protrusion 20 defining an exit port that suitably connects with a tank or other inflatable vessel 21 such as a life raft. The generator rearward end wall 22 has a central threaded opening 23 to receive a suitable attachment portion of an ignition element 24 that when appropriately actuated will ignite the propellant 14.
Partitioning wall 12 has a central fluid communicating aperture 25 the forward end of which is suitably threaded 3,515,518 Patented June 2, 1970 to mount a hollow dispersing tube 26 which is substantially closed except for a rear inlet port and a plurality of exit ports 27 distributed in predetermined spaced relationship throughout its side and forward walls.
Hot pressure gas (at approximately 2000 F.) developed upon propellant ignition passes through filter bed 15 prior to being blown into the surrounding coolant material 17 by dispersing tube 26. The coolant material, to be more fully described, is heated to a decomposition temperature of approximately 300 F. and gas products of the propellant 14 and coolant 17 are filtered through filter bed 18 prior to being delivered to the inflatable device 21 via the generator outlet port.
A preferred coolant in the form of a metallic carbonyl, such as molybdenum-hexacarbonyl Mo(CO) composition, decomposes endothermically at about 300 F. into a metallic solid and carbon monoxide gas, the latter being a permanent gas not soluble in water. The gas products of the decomposed metallic carbonyl coolant substantia ly eliminate any harmful water contribution the generator gas output, and as a result, when the gas generator delivers a predetermined pressure gas to the inflatable device, the delivered will substantially maintain the desired pressure even after cooling to ambient temperature.
It is contemplated that other metallic carbonyls, such as cobalt tetra carbonyl Co (CO) and iron nona carbonyl Fe (CO) can be satisfactorily employed to produce the desired coolant effect and sustaining gas pressure for inflating purposes.
For substantially similar test conditions for coolants in propellant actuated gas generating arrangements, the following comparative average test data was obtained for molybdenum hexacarbonyl coolant relative to a previoulsy known ammonium carbonate coolant.
Molybdenum carbonyl Max. raft pressure (at inflation)- 8.8 p.si.l.g). (23.5)
p.s. .a. Raft pressure at inflation plus 3.5 p.s.Lg. (18.2
30 min. p.s.i.a.).
Ammonium carbonate 8.9 p.s.Lg. (23.6
1.7 p.s.i.g. (16.4
77.5% retained 69.5% retained It should be noted that the 18.2 p.s.i.a. of the molybdenum carbonyl pressure will satisfactorily maintain the desired inflation, whereas the 16.4 p.s.i.a. of the ammonium carbonate developed pressure will barely satisfy the desired requirements.
Various modifications, changes or alterations may be resorted to without departing from the scope of the invention as defined in the appended claims.
1. In a propellant gas generator having a substantially hollow main body with a laterally extending partitioning wall positioned substantially mid-length of said main body and defining forward and rearward chambers therein said wall having a central aperture therethrough,
a slow burning propellant in said rearward chamber,
a dispersing tube in said forward chamber in fluid communication with said rearward chamber and having a plurlaity of apertures, and
a metallic carbonyl composition in said forward chamber and surrounding said dispersing tube.
2. The gas generator of claim 1 wherein a filter bed is positioned in said rearward chamber forwardly of said propellant, and a second filter bed in said forward chamber forwardly of said metallic carbonyl composition.
3. The gas generator of claim 2 in which said metallic carbonyl is molybdenum-hexacarbonyl.
4. The gas generator in accordance with claim 1 wherein said metallic carbonyl is molybdenum-hexa- References Cited UNITED STATES PATENTS Millns 10239 Maurice et a1. 10239 White et a1. 23-281 Hebenstreit et a1. 23-281 XR Kowalick et a1. 23 2s1 1 4 OTHER REFERENCES 5 MORRIS O. WOLK, Primary Examiner D. G. MILLMAN, Assistant Examiner US Cl. X.R.