US3439501A - Gas actuated vapor feed system - Google Patents

Description

.A r l 22, 1969 A. MOORE I GAS ACIUATED'YAIPOR FEED SYSTEM Sheet;

Fil ed Nov. 9,196?

INVENTOR. 08627? 0- #00:. Jar W A'rra wry zuewr April 22, 1969 R. A. Mock; 3,439,501 v I GAS ACTUATED VAPOR'FEED SYSTEM Filed Nov. 9, 1967 Sheet INVENTOR. 08527 1?. Moon?! By 44 9 W 07'7'042 5 United Stes Patent Patented Apr. 22, 1969 US. Cl. 60203 4 Claims ABSTRACT OF DISCLOSURE In a gas actuated feed system which has a liquid or a liquid with solids therein stoied in a tank, an oscillation damping porous metal plug-iSiprovided in the end of the supply tube leading to a vaf phi'izer, attached to a nozzle. The nozzle end of the vapqrizer is heated and radiation fins are located on the vaporizer to provide the proper temperature gradient alon the vaporizer. An enlarged liquid supply hole is provid near the end of the vaporizer. Blind holes are provide adjacent the liquid supply holes in the vaporizer to h ll, :excess liquid during oscillations of the liquid in the liquid supply tube.

Background of the invention Various systems have been used for metering flow in the vapor feed systems used in magnetoplasma dynamic thrustors. The most common of these requires the heating of the entire storage container to a temperature high enough so that the vapor pressure causes the discharge orifice to choke. Under these conditions, the flow-rate is proportional to vapor pressure which in turn is a function of the liquid temperature.

Two major disadvantages ot this system are that the vapor pressure is very sensitive to temperature and for long periods in space the electrical }power required is excessive.

Another method is to feed; the liquid bypositive displacement such as by exten'ding nested bellows. This method surfers from the pr oblem of temperature and pressure variations which cause the system to be unsteady and inaccurate due t6 vapor pressure variations dueto volume displacement of the bellows due to these variations.

Summary of the invention According to this inventioiiga gas-actuated feed-system is used. The major difficultyi with a gas-actuated feed system is the stabilization oi the vapor flowing from the sonic nozzle orifice due to, the tendency of the liquid column to oscillate at a frequency of 1-10 cycles per second. The unique featurepf this invention relates to the means of stabilization otfthe vapor flowing from the nozzle. This is accomplished by incorporating a porous plug in thetinlet tube leading'to the vaporizer, the provision of blind holes in the vaporizer parallel to the vaporizer holes and by the establishment of the proper temperature gradient in the vaporizer.

Brief description of the drawing FIG. 1 is a schematic diagram of a gas-actuated vapor feed system according to the invention;

FIG. 2 is an enlarged view of the vaporizer unit of the device of FIG. 1; r

F1613 is a sectional view of the device of FIG. 2 along the line 3--3; and

FTG. 4 is an enlarged sectional view of the device of FIG. 2 along the line 4-4.

Description 0 the-preferred embodiment Reference is now made to FIG. 1 of the drawing which shows a liquid supply tank 10 having a heating coil 12 surrounding the tank to melt any solid material in the tank. The power requirements for this coil are not as great as for the system described abovei-l The tank may contain various liquids or mixtures of i quid and solid particles, but in use for which it was constructed the material 14 used is liquid lithium. The heating coil 12 may not be needed when no solid particles {are in the liqiiid. A vaporizer shown schematically at 16 is com nected to the tank 10 by means of a liquidgffeed tube 1 7 .j'fA porous metal plug 18 of a material such as tungsteii" is located in. the endof tube 17 withinl 'the tank 10 for filtering and damping oscillations withiii the tube 17. ';I A gas under pressure such as, argon is sii'pplied to the tank 10 through an inlet tube 22. A pressure regulator 24 and pressure gauge 25"ar'eT provided irijthe inlet tube 22. The pressure regulator may be either manual or automatic depending upon the particular use of the ap iaratus.

Since the porous plug 18 will not damp out all oscillatioris, a plurality of blind holes 27, shown in FIGS. 3 an j4, are provided in the vaporizer and are located around the supplyvholes 28. 7

The end of the vaporizer 16 is connected to the anode 29 }hf the dynamic thrustor The anode is heatedby the discharge between cathode '30 and anode 29 and this heat is conducted to the vaporizer 16. If the vaporizer 'is used forjotherpurposes, a separate heat source such as an elet'itr'ical heating element, may be provided adjacent the endijljof the vaporizer 16. 4

Radiation; fins 31 are spaced along the outer surface of j the vaporizer 16 to establisha proper temperaturegradient along its length An enlarged passage 33is provided in the vaporizer leading to the annular nozzle orifice 34in anode 29-. 1 The oscillations of the liquid column are stabilized by 'holes 27 to supply any deficiency of vapor from supply holes 28.

If the oscillations are such that an excess amount of fluid enters the blind holes, though not shown, a return to the liquid supply may be provided from these holes.

There is thus provided a vapor feed system that does not have the disadvantages of prior art systems.

While a certain specific embodiment has been described, it is obvious that numerous changes may be made without departing from the general principles and scope of the invention.

claim: 1

11. A gas-actuated vapor feed system comprising: a liquid supply container having vaporizable liquid therein; a vaporizer havinga sonic nozzle connected at one end thereof; a supply tube having one end immersed in said liquid and the other end connected to said vaporizer at the end thereof opposite said nozzle; a porous metal plug in the end of said supply tube immersed in the liquid; said vaporizer having at least one liquid passage therethrough; an enlarged liquid passage in said vaporizer at the end adjacent" said nozzle; means for heating the end of said vaporizer adjacent said nozzle whereby a temperature gradient is provided along the length of said vaporizer; means for supplying a'gas under pressure to said supply container whereby liquid is supplied to said vaporizer; means for controlling the .pwsure of said gas to thereby control the flow of said liquid.

in the establishment of the temperature gradient along the length of the vaporizer.

References Cited UNITED STATES PATENTS 3,350,884 11/1967 Colombani 60-203 3,359,733 12/1967 Forbes 60202 3,359,734 12/ 1967 Ferric et al. 60203 10 CARLTON R. CROYLE, Primary Examiner.

US. Cl. X.R., 219-l21

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