US1199700A - Apparatus for liquefying gases with a low boiling-point. - Google Patents

Description

G. HILDEBRANDT.

APPARATUS FORLIQUEFYING GASES WITH A LOW BOlLlNG POINT.

APPLICATION FILED JAN. 9, I911.

Patented Sept. 26, 1916.

34119 e/nlo's,

6.192 Zdebmndl'.

sa'aans PATENT curios.

GOTTHOLD HILDEBRAND'I, OF SPANDAU-TIEFWERDER, NEAR BERLIN, GERMANY,

ASSIGNOR, BY MESNE ASSIGNMENTS,

TO AMERICAN INDUSTRIAL GAS COM- PAN'Y, OF NEW YORK, N. Y., A CORPORATION OF YORK.

APPARAYID 'S FOR LIQUEFYING GASES WITH A LOW BOILING-POINT.

, To all whom it may concern l the discharge aperture.

Be it known that I, ,Go'r'rHoLD HILDFP BRANDT, engineer, citizen of Germany, subject of the King of Prussia and Emperor of Germany, residing at Spandau-Tiefwerder 2%, near Berlin, in the Kingdom of Prussla and Empire of Germany, have invented new and useful Improvements in Apparatus for Liquefying Gases with a Low Boiling-Point, of which the following is a specification.

The liquefaction of gases with a low boiling point has heretofore generally been effected only by the'regenerative method in-' dicated by Siemens in the year 1857 which consists in compressing, cooling and expanding these gases such for example as-nitrogen, oxygen, hydrogen and so forth, and conducting the cooled gases thus obtained in counter current to fresh compressed gases, thereby producing an interchange of heat, which ultimately results in the desired liquefaction. In accordance with Various systems this expansion has takenplace either in a counter current system or pipes or in. open cavities. This method has presented the defect that thediquefying period occupies a considerable time as the greatest cooling which is theoretically possible cannot be reached owing to the apparatus employed, because with this method of expanding, the frictional resistances of the counter current? system. of piping do not permit of fullyutilizing the energy supplied in. the compressed gases, and by this method it is impossible to utilize the kinetic energy of the gas molecules obtained by expanding to such an extent that their pressure falls below' It is well known that compressed gas-y when it issues through an aperture into a space of less pressure and'escapes'with an increased kinetic energy, is cooled close to This cooling (called by Travers velocity cooling) has not been 1 used up to the present time for the liquefication or' the separation of gas although it represents a very rich source of cold because this cooling exists only immediately after passing through the aperture and disappears at a relatively short distance from the aperture, the velocity of the stream, of gas being reduced by friction caused by its impinging against the wall of the vessel v Specification of Letters Patent.

Application filed January 9,

- ually increasing evolved-by such differences that the expansion part of Fig. 4.-

The nozzle C has velocity increases in the gas has fallen to 800 13111., that *is to say to a Patented Sept. 26.

Serial No. 601,614.

into which it flows. Therefore in order to produce low temperatures cooling by utiliz- 1ng theJoule-Thompson effect only was applied which is the result of the internal work only caused by the expanding gas.

have now succeeded in utilizing the velocity cooling for the continuous cooling and liquefication of gases and the separation of gas mixtures by applying a particular form of expanding nozzle and the space. into which the expanding gas stream flows.

The apparatus hereinafter described is deslgnedto avoidthe loss of energy which is present in existing systems, and to this end the expansion is effected in a space of gradcross-sectional area, for 7O stance in one ormore nozzles of the type Laval, the smallest and largest, cross sections of these nozzles presenting of the gasin the nozzle belowthe pressure of the atmosphere.

In the accompanying drawings Figure 1 represents alongitudinal section of a simple form of apparatus embodying this invention; Fig.2 is form with a device for transferrin to the compressed gas; Figs. 3 and sent'similar views of another form'of being ience I1n illustration.

In the "drawings the preliminarily cooled f .f compressed gas. passes through the tube A expansion valve" B .into the nozzlexO.

a conical form of grad-v and ua'lly increasing sectional area.

f Taking the admission pressure of the preliminarily cooled compressed gas by way of I example as 100 atmospheres equal to 100' kg. per square cm. and the admission apertureA-bf the nozzle C as l'squar'e 'mm. the correspondence with the'diminishing pressure in the nozzle. The

molecules then separate more and jmore' fromgeach otherand when the width-of the opening of the nozzle has to say presents a who tothe admission aperture of 1 to 1250, the pressure ofg/ reached 40mm. that is gramsper square" min-us fsomewhat'more than one-fifth o fihere.

an atmoschamber itself may fall .75

a similar View of another 80- the cold '5 4 repre ff I the I apparatuswith an enlarged inlet snace,a

broken off fo conven- 85 ressure. f- 1 05 g It is therefore important that the Q I I ower aperture as compared with the upper I 'sponding heat equivalent disappears and as the process takes place almost adiabatically' this is only at the cost of the temperature ofa part of the expanded gas.

Rankine has already shown that the adiabatic expansion of superheated steam causes its condensation and in the Laval nozzle a highly heated liquid is converted by cooling into a mixture of liquid and vapor. The

' present invention is based on similar physical principles. In the first place the specific heat of the expanded gas and the partitions is consumed to cover the expenditure of heat, then as soon as the-pressure falls below atmospheric pressure a part of the gas mustyield up its latent heat, that is to say it liquefies, but at first these liquid particles retain the velocities of the former gas mole-,

' cules exactly like the steam condensate of a v special air pumps.

cause the nozzles to open into a collecting steam generatorfeed injector. It is an advantage of the system that this reduction of pressure below atmospheric pressure takes place merely by an increase of the velocity of'the molecules .without the necessity for Thus it is possible to nozzle E (Fig. 2) or a collecting tube and to convert the velocity into pressure without risk of the liquid obtained again vaporizing.

It is of course necessary by suitably forming the nozzle to prevent any friction of the gas at the nozzlewalls when the-gas pass--- ing therethrough is under higher pressures. For this purpose the portion of the nozzle near its inlet end is enlarged, as diagrammatically shown inFigs. 3 and 4. At the a u inlet of the gas the ,expanslon reservoir is enlarged to a cylindrical space G so that the jet of the gas issuing from the valve B or the like does not touch the walls. In consequence of injector action or suction avacuum is formed at the outer ends H of the enlarged space G, which assists the cooling action. A purely adiabatic expansion is not possible because the metallic nozzle and the supply pipe conduct their heat to the expanded gas. In'order to. avoid this defect the cold imparted to the expansionvalve B is transferred by a device shown in Fig. 2 directly to the compressed gas before the expansion and not only cools it but its property of being a poor conductor of heat takes place durin nozzle with a gas envelop which is a poor conductor. With this object the nozzle C is made of a substance which is a good conductor such as copper, and inserted in a vessel D which receives the cooled compressed gas from the inlet (A). From the vessel D the cooled compressed gas is conducted to the expansion valve B, from which it is expanded into the conical nozzle 0. This apparatus is likewise utilized for sepa rating any foreign gases with a high boiling point from the compressed gas to be liquefied before it can exert any harmful eiiect by stopping the valve. Thecooling which the expansion process in the copper nozz e is consequently transferred directly to the compressed gas before its expansion and gradually cools it sufliciently to cause the foreign substances of higher boiling point as for instance watervapor, carbonic acid, etc., contained in the compressed gas to be precipitated as liquid or solid bodies which can be drawn ofi through a special pipe F in the bottom of the vessel 1).

1 f Having now described invention what I claim and desire to secure by Letters Pat- .ent'of the United States is: v

. 1. lncan apparatus for liquefying gases with a low boiling point, a conduit for the compressed and cooled gas, and an expan sion nozzle arranged to receive the gas from said conduit and to expand and liquefy the same, said expansion nozzle having a crosssectional area which gradually increases substantially as the square of the distance from the point of admission of the gas, the

ultimate dimensions of said area being small as compared to the length of the nozzle, and said nozzle being so proportioned as to ef- 'fect velocity cooling of the gas expanding therein.

2. In an apparatus 'for liqu'efying gases with a low'boiling point, a-conduit for the compressed and sealed gas;}and an expansion nozzle arrangedto receive the gas from said conduit and to expand and liquefy the same, said expansion nozzle having an enlarged portion at its smaller end and being of gradually increasing cross-sectional area and being so proportioned as toefiect velocity cooling of the gas expanding in said nozzl'e of gradually increasing area.

3. In an apparatus for liquefying gases with a low boiling point, a conduit for the compressed and cooled gas, an expansion nozzle arranged to receive the gas from said conduit and to expand and liquefy. the'same, and a vessel surrounding said nozzle for receiving the gas in its passage from said coni ice 7 duit to the inlet ofthe nozzle, said expan- I sion nozzle being of gradually increasing cross-sectional area and being so proportioned as; to effect substantially adiabatic 65 is utilized for surrounding the expansion expansioniegt. the gas therein.

-, of gradually increasin and cooled gas,

4. In an apparatus for liquefying gas with zle of gradually increasing cross-sectional area, having a substantially smaller crosssectional area at its inlet than its outlet, and being so proportioned as to effect substantially adiabatic expansion, said nozzle being in connection with sai expansion valve, the admission aperture of said nozzle having a substantially smaller cross-section than the discharge aperture, and the conical nozzle being proportioned to effect velocity cooling of the gases expanding therein.

a low boiling point, an expanslon 1102- cross-sectional area 7 6. In an apparatus for liquefying gases with a low boiling point and in particular atmospheric air and hydrogen gas the combination of a conduit for the compressed and cooled gas, an expansion valve at the end of said conduit, with a conical nozzle of gradually increasing cross-sectional area in connection with said expansion valve, the admission aperture of said nozzle having a substantially smaller cross-section than the discharge aperture, a part of said conduit being arranged in a heat-conducting contact with the portion of said nozzle near the said expansion valve.

In testimony whereof I have hereunto set my hand in presence oftwo subscribing Witnesses.

GOTTHOLD HILDEBRAND T.

Witnesses WOLDEMAR HAUPT, HE RY HASPER.

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