US2504314A

US2504314A - Vaporizing apparatus

Info

Publication number: US2504314A
Authority: US
Inventors: Feick George
Original assignee: Arthur D Little Inc
Current assignee: Arthur D Little Inc
Priority date: 1945-01-17
Filing date: 1945-01-17
Publication date: 1950-04-18
Anticipated expiration: 1967-04-18

Description

Ap 18, 1950 G. FEICKJIII VAPORIZING APPARATUS 4 Sheets-Sheet 1 Filed Jan. 17, 1945 In venfor flymfi By 4 12574 Age/7f April 18, 1950 G. FEICK, III:

VAFORIZING APPARATUS Filed Jan. 17, 1945- 4 Sheets-Shed 2 April 18, 1950 ca; FEICKJII 2,504,314

VAPORIZING APPARATUS Filed Jan. 17, 1945 4 Sheets-Sheet 3 I l/vpur l IlllH Hill! Age/77" G. FEICK, 111: 2,504,314

April 18, 1950 VAPORIZING APPARATUS 4 Sheets-Sheet 4 Filed Jan. 17, 1945 F awz-z/z By W Patented Apr. 18, 1950 VAPORIZING APPARATUS George Feick, III, Boston, Mass., assignor to Arthur D. Little, Inc.', Cambridge, Mass., a corporation of Massachusetts Application January 17, 1945, Serial No. 573,296

8 Claims. (Cl. 62-1) 1 2 This invention relates to an apparatus for supchamber of the apparatus along line II of plying a normally gaseous fluid in gaseous form by Fig. 4;

controlled vaporization thereof from its liquid form absorbed in a fibrous material contained in a closed chamber.

'In accordance with this invention there is provided an apparatus designed primarily for semiportable use and installation, and which is accordingly eminently suited for purposes where bulky equipment cannot be conveniently usedfor example as a source of gaseous oxygen, nitrogen, lower hydrocarbons, and other gases for shop or commercial operations such as welding or carrying out chemical reactions, andof breathing oxygen in hospitals, and also in aircraft and elsewhere where there is a deficiency in oxygen in the air.

Particular features and advantages of this apparatus are the freedom from surging and venting losses during operation, the ability to operate in any position for any length of time without loss of fluid, relatively small size and weight in proportion to capacity and performance, automatic control of the vaporization of the contained liquefied gas, and means for measuring readily the amount of said liquefied gas in the apparatus at any time.

While these features are advantageous for any liquid vaporizer, they are of particular importance for Vaporizers which are subject to changes in position, especially during operation, as they permit freedom of movement without danger from upsetting the vaporizer. Most significantly is this true when this apparatus is used to furnish oxygen for the crews of high-flying combat aircraft, where the apparatus may be in any position at any time, and may change its position very quickly.

The purposes of this invention are attained by providing a hollow walled chamber substantially filled with a mass of inert fibrous material, the walls of the chamber being evacuated to reduce heat loss, suitable means for filling the chamber with liquefied gas which becomes absorbed in the fibrous mass, a heating element for vaporizing the liquefied gas at a regulated rate, means for removing vaporized gas from the chamber, and means for measuring the amount of liquefied gas contained in the chamber, the latter means being associated with a remote-indication device.

These and other features of the apparatus will be described in greater detail below with reference to the accompanying drawings, wherein Fig. 1 represents a cross-sectional view of the Fig. 2 represents a cross-sectional view of the head of the apparatus, together with part of the chamber as shown in Fig. 1, and is taken along line II-II of Fig, 3; A

Fig. 3 represents a sectional view at right angles to the axis of the head of the apparatus, and is taken along line III-III of Fig. 2; and

Fig. 4 represents a sectional view of the chamber of the apparatus at right angles to the axis of the chamber and is taken along line IVIV of Fig. 1.

The gaseous fluid produced by the apparatus of this invention is conducted away through one or more suitable conduits to the point of use-e. g.

to a welding torch, an oxygen mask or a zone of chemical reaction. Electrical power to operate the apparatus is led to it by wires communicating with suitable sources of such power. Since such connection is to fixed sources, at least in most instances, the apparatus is referred to as semiportable rather than portable, although under some circumstances it can be made fully portable for use by an individual-e. g. when made in sulficiently small size and when omitting that portion of the apparatus which relates to the measuring of the amount of liquefied gas in the apparatus.

While the device herein described is of particular value for providing gaseous oxygen from liquid oxygen, and will be hereinafter described principally with reference to oxygen, it may be used in the same basic form and manner for other fluids which are normally gaseous at or about ordinary pressures and temperatures but which, like oxygen, can be liquefied. Thus included, for example, are nitrogen, argon, methane and other gaseous hydrocarbons, and other gases, as well as mixtures of gases, providing they are not corrosive or injurious to the apparatus or to the fibrous filling. Among the useful purposes served by the apparatus of this invention is that of supplying a controlled amount of a gaseous fluid Whose boiling point, at atmospheric pressure, is close to ordinary room temperature: Such fluids, e. g. diethyl ether and various hydrocarbons such as normal and iso-pentane, may be gaseous when the surrounding atmosphere is hot, and liquid when such atmosphere is cold, thus causing dimculty in the utilization of such fluids when the temperature of their surroundings is close to their boiling points or I varies both above and below it during such utilization. By using the apparatus herein described, it is possible to retain such fluids in liquid form, and supply them in gaseous form in desired quantities.

Referring now to the drawings: the body of the apparatus comprises a chamber represented generally by the numeral 51 and made up of an inner wall consisting of two more or less hemispherical metallic shells IB, i6 suitably sealed together at their peripheries, and a similar outer wall consisting of more or less hemispherical metallic shells 23, 23'. Between these walls isthe evacuated space 58, and within the inner wall I6, i6 is the fluid space 58.

Communication with

spaces

58 and 59 is had through a head assembly, shown in Figs. 2 and 3, which comprises a head 4, a cap 2 therefor, a valve assembly I attached to said cap 2, and a connection cover 8. The head 4 consists of a plate or disk 31, an outer skirt or flange 36, and an inner skirt or flange 38. In the outer skirt 35 are positioned the various control devices, power leads and oxygen (or other gas) outlet. These are held in suitable bushings 9 (see Fig. 3)

I of which six are shown spaced equidistantly around the periphery oi skirt 36. The particular arrangement of these devices around the periphery is not material to the proper functioning of the apparatus; their number and location depend upon the particular conditions of use and construction in any given instance. In the arrangement illustrated in particular in Fig. 3, there are shown, the pressure switch with adjusting nut 54, thermostatic switch 46 with bulb 4'l projecting into the space within skirt 38, pope valve 48, lead-in insulators 49 and 5t, and oxygen outlet connection 5| which is controlled by valve 62. The apparatus is grounded through lead 43,attached to the head 4 by screw 44. Lead 53 passes from a source of electric power for heating through switches 45 and 48 and insulator 49 to the heater lead,25. Lead 52 connects the 09ndenser lead 24, through insulator 50, with a suitable capacitance indicating instrument 68. The

loads

24, 25, 52 and 53 are all insulated to prevent contact with each other and with metallic parts of the apparatus.

Positioned centrally in disk 3! is inner neck 8, and concentrically within said neck is filling tube 3. Filling tube 3 projects into bushing 39 of valve assembly 6, said bushing 39 being positioned centrally of cap 2. Valve head 4!! is screwed onto bushing 39, and contains an inlet 60 and a ball 4i held in position against said inlet by spring 42.

In the inner skirt 38 is positioned the vacuum connection l, having opening 55 leading to the outside. The space 58 is evacuated through connection I, and when a sufliciently high vacuum is attained the opening 55 is sealed-for example by pinching oil and then soldering a copper tube previously fitted tightly into opening 55 and through which the space 58 was evacuated. Connection cover 8, which may conveniently consist of a rectangular strip, is then bent around skirt 38 and connection 1, andfastened in place by screws 35.

Mounted axially in the head end of inner shell i6 of chamber 51 is outer neck i5, which is concentric with inner neck 6. Outer neck l5 projects outwardly from inner shell it into evacuated space 58, and this projection serves to hold support bushing i? which fits into bushing retainer 18 which in turn is firmly attached to the inner wall of outer shell Z3--thus serving to position the head end of the inner shell. The other end of the to outer shell 23' by support bushing l'l held in 4 bushing retainer l8, bushing I! being mounted on capsule l8 which. like outer neck l5, projects through the wall of the inner shell. Support bushings l1, II, which are made of heat-insulating material, are provided with holes 34 to permit free communication throughout space 58.-

Capsule l9 consists of a cylindrical shell 32, upon which bushing 11' is mounted, a. solid plug 30 at its inner end, and a screen 3| near its outer end, the space within shell 32 between plug 30 and screen 3| being filled with a suitable adsorber such as activated charcoal. Since shells IS, IS and 23, 23' will ordinarily be made of metal, and since in metal vacuum containers there is always a slow diffusion oi gas from the walls and hence a tendency to destroy the vacuum, an adsorber such as that just described is necessary, to adsorb such gas and maintain the vacuum. By such means the vacuum may be maintained over a ver long period of time. The screen 3i serves to hold the adsorbent in place while permitting free communication with vacuum space 53.

Outer neck l5 and inner neck 8 are positioned relatively to each other by metallic bushing 33, which forms a tight seal to prevent passage of gas between fluid space 59 and the space between necks 6 and I5. Inner neck 6 projects a short distance beyond bushing 33 into fluid space 59, while filling tube 3 projects still further into fluid space 59. Fitted closely over this projectin end of inner neck 6 is outlet duct 20, which is provided with a hole through which filling tube 3 passes.

Heating cylinder 2i, located within fluid space 59, is preferably foraminous to permit sumciently free movement of gases and liquids within fluid space 59. It may accordingly consist of wire mesh or of thin sheet metal Preferably perforated, as shown in Fig. 1; or it may be imperforate, as shown in Fig. 2.

Attached to cylinder 2i are fins 21; of adequate number and shape to promote transfer of heat from cylinder 2i into and throughout the mass of mineral fibers within fluid space ESP-said mass of fibers occupying all of the free space within fluid space 59. Heating of cylinder 29 is accomplished by power supplied from lead 55 through lead 25 which passes out of outlet duct 20 and thence in a series of turns around the outside of cylinder M, to which it is grounded at the end of these turns, as shown at 25a. Since cylinder 2! may be fitted rather loosely within inner shell l6, it (although not being free to move to any significant extent because of the mineral fiber packing and the curvature of the walls of inner shell it, IS), cylinder 2| should be in turn grounded to shell l6, l6. Thus current can readily pass, when permitted by the

control switch devices

45 and 56, from lead 25 to cylinder 2| to shell l6, l5, and thence through outer neck l5, bushing 33, inner neck t, head 4, and lead 43, to the ground. 1

Thermostatic switch 46 is actuated by the pressure of a suitable compound (such as chloroform, when the fluid is oxygen) which vaporizes if the temperature within fluid space 59 rises too high. This compound is contained in a bulb 26 positioned within space 59 and communicating with the interior of bulb 41 by means of tube 5, which passes through the annular space between filler tube 3 and inner neck 5. chloroform or other suitable compound is charged into the thermostat bulbs 26 and 4'! and tube 5 through the lead tube in; after filling, this lead tube ill may be sealed n as indicated at end 56. Connection cover 8 serves to protect from damage end 56 as well as the sealed opening 55, and is put in position, as already described, after both are sealed.

In vaporizing apparatus of the type herein described, where the fluid space 59 is filled with mineral fibers, the conventional float-type liquid-level gage cannot be used because there is no free liquid surface in said space 59. In accordance with the present invention there is therefore provided a means whereby the liquid content of fluid space 59 may be measured, and read on an indicating means 6! which may be located at a point, remote from the apparatus and which is connected to the apparatus only by lead 52. This method of measuring the liquid content of the apparatus is especially advantageous in military aircraft installations, for example, where the apparatus may be desirably installed at a point which, at least during flight, is inaccessible to the crew.

In order thus to measure, at a, point which may be remote from the apparatus, the amount of liquid oxygen or other liquefied gas contained in fluid space 59, a suitable number of condensers 22 (of which eight are used in the device here illustrated) are provided in said space 59. Each of these condensers is grounded to any suitable part of the apparatus (e. g., outlet duct 20) by ground leads 28, and is connected to a suitable indicating instrument 6! through leads '24 connecting with lead '52. Each condenser 22 is conveniently made of two strips of

aluminum foil

62, 53 spirally wound upon an aluminum bobbin 29, and insulated from each other and spaced from each other and from the rest of the apparatus As hereinafter pointed out in more constitutes an accurate measure of the liquid content of fluid space 59. As stated above, each condenser is grounded by ground leads 28; these leads 28 are connected at one end to any suitable part of the apparatus and at the other end to one of the foil strips 62, 63 of each condenser. The other of the foil strips 62, 53 of each condenser is connected through leads 24 and 52 to indicating instrument 5 I, as stated above.

Instrument 6| may be any suitable'device, of which several are known, for indicating the capacitance of condensers 22. It may, for example, be a capacitance bridge circuit, and the meter may be calibrated in terms of the content of liquefied gas of the present apparatus. When this instrument Si is energized by a suitable power supply (indicated by the word Input in Fig. 3), the liquid content of the apparatus will be shown on the dial (marked MA) of instrument 5|. Instrument 6| may be at considerable distance from the apparatus, thus providin suitable remote indication of the content of liquefied gas.

For some purposes, it may not be necessary that the device of this invention embody any provision for measuring its content of liquefied gasin which instances the condensers 22, leads 24 and 52, and instrument 6| may be omitted. Ordi.

narily, however, such measurement is either highly desirable or definitely necessary.

The filling-material for fluid space 59 must obviously be unafi'ected by and inert to the contined fluid in either its liquid or its gaseous form. )rganic materials are therefore unsuitable for some fluids, e. g. oxygen, although permissible for inactive gases such as nitrogen and argon. Furthermore, the filling material must absorb all the liquefied gas contained in space 59 so that no free liquldis present to spill out of outlet duct 20 if and when the apparatus is inverted; also, the filling material should not be fine or dust-like as it would then be conducted out through outlet duct 20 with the vaporized gas, contaminating the latter and depleting the filling material in space 59. The filling material which meets these requirements for all gases in gaseous or liquid form with which this apparatus may be used is mineral fiber, e. g., glass wool, mineral wool, or

asbestos, in fine fiber form. Glass wool substantially free from shot and dust has been found exceptionallywell adapted as a filling material when the apparatus is filled with oxygen. Organic fibers may be used, as already indicated, with inert gases.

In general, it has been found desirable to have a comparable density of packing of the fiber in the fluid space 59 and that in condensers 22. That is, if the former is tightly packed, the latter should be, and if the former is loosely packed, the latter should be. This arrangement permits more adcurate readings of the content of liquefied gas since these readings are based upon capacitance measurements of a condenser having a porous absorbent material (the fiber) as a dielectric, the capacitance varying with the amount of liquefied gas absorbed by the porous absorbent material. It follows that the absorbent material of the condenser is therefore a part of all the absorbent pop valve t8 and outlet connection 5! being in a.

more or less horizontal position.

Lead 52 is connected to the instrument 6!, and lead 53 to a source of electric power for heating. Any suitable sources of electric power may be used for each purpose; for example, when the installation is in an airplane, instrument 5| will ordinarily beconnected with 400 cycle 115-volt power supply and. lead 53 with 28 volt D.- C. power supply. These figures are not critical as long as the desired results are attained-e. g., for heating, it is obvious that the electric power supplied through lead 53 may be at one volt or 100 volts or otherwise, since the power is supplied for whatever time is required to vaporize fluid in space 59 at the desired rate, as described in more detail below. It is of course obvious that the characteristics of the heater wire 25 surrounding cylinder 2 I will have to be suitable for use with the particular voltage or voltage range employed.

The filling and operation of the apparatus of this invention will now be described with reference to oxygen as the filling fluid. The apparatus is first filled from a suitable supply of liquid oxygen, by forcing said liquid oxygen, under pressure of say 20 to 65 p. s. i., through inlet 60 in valve assembly I whence it passes into fluid space oxygen) and to purgethe air present. In subse quent fillings, vaporization of the oxy en will principally be necessary only to accomplish whatever cooling is required. A vaporizer of the construction shown in the drawings, and having a fluid space about seven inches in diameter and 10 /2 inches in length, holdsabout 9.to 10 pounds of liquid oxygen. When filling is completed, pop

valve 48 and valve 52 are closed, valve head 40 is preferably capped, and the power supply to instrument 5| is turned on.

introducing said fluid in liquid form into said con- The apparatus may be charged at atmospheric pressure, or at operating pressure-which is conveniently about 65 p. s. 1. under the conditions Just given. If charged at atmospheric pressure, operating pressure may be attained by turning on the heater (by supplyin power through leads 53 and 25) for a few minutes. When operating pressure is attained, gaseous oxygen may be withdrawn through outlet connection 5|, at any rate up to about 40 cubic feet per hour under the conditions given herewith.

vaporization of the oxygen is effected automatically, as already briefly indicated. In more detail, electric power fed in through lead 53 and thence to lead coiled around heating cylinder 2| serves to heat the latter, the heat being transmitted throughout fluid space 59 by means of said cylinder 2| and fins 21. Such heat causes vaporization of some of the liquid oxygen, with consequent rise in pressure within fluid space 59. Sufflcient risein pressure and temperature causes shutting off of the power fed in through line 53, since when a high enough pressure is-reached switch 45 is actuated to cut the power, and when a high'enough temperature is reached the vaporization of the chloroform or other material within bulb 25 actuates thethermostatic switch 46 to cut the power. Hence the apparatus and its op-.

eration are doubly protected, as the

switches

45 and 45 act independently. Extra surges of pressure, if any should occur, are cared for by pop valve 48. The operating pressure may be controlled by turning the adjusting nut 54 on switch- 45, thereby increasing or decreasing the pressure required to actuate switch 45. Similar. provision for adjustment may be had in switch 45, although in practical operation the switch 45 is initially set to the proper position and not subsequently adjustedadjustments being made only in switch 45. Under some conditions or with some fluids it may be unnecessary to have both switch 45 and switch 46; either may then be omitted.

Although the apparatus is thus protected against overheating, the lead 53 should be disconnected from the power supply when the apparatus is not in use, to avoid unnecessary vaporization of any liquid oxygen within the apparatus. Any excess pressure then developed will be relieved by the pop valve. 1

In the event of power failure, the apparatus will continue to supply gaseous oxygen as long as it contains liquid oxygen, but such supply will be at a lower rate and (unless this rate is vary low) at a lower pressure than normal.

The rate and pressure of the outputof gaseous fluid from the apparatus of this invention can be readily adjusted .or designed to meet particular conditions of use. Thus, the size of the apparatus, the wall strength of metallic shells 15, I6 of chamber 51, the adjustment of switches 45 and :46, and the power input for heating, may be made or designed in whatever ways are suitable for any given conditions of use. The description given herewith is for purposes of illustration, and not as tainer, means for conducting said fluid in gaseous form out of said container, a heating element within said container, said heating element being foraminous and provided with radiating fins,

,means for conducting electric power to said heating element to efiect the heating of the contents of said container, means for controlling the supply of said electric power, a mass of fibers substantially filling the space within said container, said mass being adapted to absorb substantially all said liquid within said container, said fibers being inert to said liquid, and means for measuring the amount of liquid within said container at any time, said last-named means comprising condenser means positioned among said fibrous mass and comprising a pair of conducting surf faces separated and insulated from each other by means of a body of flbers which is also adapted to absorb said liquid and is inert thereto, and

.means connecting one of said pair of conductin surfaces with external means for measuring the capacitance ofsaid condenser means. I

2. Apparatus according to claim 1, wherein said fibers are mineral fibers.

3. Apparatus according to claim 1 wherein said fibers are glass flbers.

4. Apparatus for converting from liquid togaseou's form a fluid which is gaseous at about normal room temperature and pressure, which comprises a closed container, means for introducing said fluid in liquid form into said container, at mass of fibers substantially filling the space within said container, said mass being adapted to absorb substantially all said liquid within said container and being inert to said liquid, a heating element within said container, fln members attached to said heating element and extending into said mass of flbers and being adapted to transmit heat from said heating element into and throughout said mass of fibers, means for heating said element and thereby converting said liquid into gaseous fo rm,means for conveying the resulting gas out ofsaid container, and means for measuring the amount of liquid within said container at any time, said last-named means comprising condenser means positioned within said container. and means for measuring the capacitance of said condenser means. 5. Apparatus for converting from liquid to gaseous form a fluid which is gaseous at about normal room temperature and pressure, which comprises a closed container, means for introducing said fluid in liquid form into said container, a mass of fibers substantially filling the space within said container, said mass being adapted to absorb substantially all said liquid within said container and being inert to said liquid, a heating element within said container, fin members attached to said heating element and extending into said. mass of fibers and being adapted to transmit heat from said heating element into and throughout said mass of fibers, means for heating said element and thereby converting said comprising condenser means positioned within said container and among said mass of fibers, said condenser means comprising a pair or conducting surfaces separated and insulated from each other by means of a body of fibers which is also adapted to absorb said liquid and is inert thereto, and means connecting one ofsaid pair of conducting surfaces with external means for measuring the capacitance of said condenser means.

8. Apparatus according to claim 5, wherein said condenser means comprises a plurality of condensers each of which consists of a pair of spirally-wound conducting surfaces spaced apart by fiber Of the same type as that filling said container, one of said pairs in each of said condensers being grounded and the other of said pairs being attached to said external means for measuring capacitance, said latter means being similarly rounded.

7. Apparatus according to claim 5, wherein said fibers are glass fibers.

8. A device for containing liquefied gas and for generatin and supplying gas from said liquefied gas, comprising an insulated pressure container,

means for introducing said liquefied gas into said container, a mass of mineral fibers substantially filling the space within said container, said mass being adapted to absorb substantially all said liquefied gas within said container and being inert to said liquefied gas, means for supplying heat to said liquefied gas within said container to convert the same info gaseous form, said last-mentioned means comprising a heating element, means for heating the same, and heat-conducting members attached to said heating element, said heatconducting members extending into said mass of mineral fibers and being adapted to transmit heat from said heating element into and throughout said container, and means for measuring the capacitance of said condenser means.

GEORGE FEICK, III.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date 1,863,958 Wulfi et a1 June 21, 1932 2,103,741 Bencowitz Dec. 28, 1937 2,158,458 Mathis et al May 16, 1939 2,254,587 Williams Sept. 2, 1941 2,385,984 Hansen et a1 Oct. 2, 1945