USRE10725E - Process of reducing temperature - Google Patents

Description

E; E. HENDRICK.

I PROCESS OF REDUCING TEMPERATURE. N0. 10,725. Reissued May 18, 1886.

q/vihwooco S H van lo z val/0. 3313 afizuc v zen of the United States, residing at Garbon-' Iran STATES ELI E. n1;::na1o1 or OARBONDA LE,

PATENT OFFICE.

rnxssrnvnuin P R c essrotis aanuc m a: EM PEI-RATU RE.

/ :EPECJII'ICATION forming part'of Reissued Letters Patent No. 10,725, dated May 18, 1886.

Original No. 336,234, dated February 16, 1886; Applioation'for reissue filed April 24, 18st Serial No. 200,081.

To all inhom; it concern: i

be itknown that I, ELI E. HENDRIOK, a citidale, Lackawanna county, in the State of Pennsyltfan'ia'have invented certain new and useful Improvements in Processes. of Reducing Tem pe'rature, or, as it is commonly called, the artificial production of cold, depending on the liberation of ammonia-gas'from its aqueous solution, its Subsequent condensation under pressure to a flniid, and its expansion into a gaseous form again, of which the following is a specification. g

My invention also relates to improvements in the apparatus. necessary to carry out the My invention, as far' s it relatesto the prd cess, consists, first, in thense ofexhauststeam, I

or steam which has already been employed in the performanceof mechanical work, to liberate the ammonia-gas from its aqueonssolution, and inso proportioning the strength ofthe aquaarnmonia employed that the ammoniagas liberated from it shall have the tension required for its condensation to a liquid at any reason able temperature of the cooling-water.

; Secondly, the process consists in superheating the exhaust-steam thus employed.

Thirdly, the process consists inthe'employment of steam direct from the boiler inconjunction with the exhaust-steam, either superheated orotherwise, for thcpurpose of aiding the liberation of the ammoniagas.

engine, and the exhaustrpassage of the steam My improvements in the apparatus consist in the combination'ofa boiler, asteampumping-engine, or other steanrengine, and a still with pipes connecting the boiler to the steaminduction of the steam pumping or othersteam pumping or other enginewith suitably arranged steam-coils in the still,of a boiler, a steam-engine, and a still. connected as above described, and also having a pipe connecting the still directly to the boiler, and of a boiler, a steam pumping-engine or other st eam-engine, a still, and a superheater, these parts being connected by pipes as follows: The boiler being connected with the pumpingengi ne, the exhaust of the pumping-engine with the superheater, the superheater' with the still,'and the boiler also being connected directly with the still.

quainted for the purpose of carrying out my 6 invention thelatteris notrestricted to the precise form of the apparatus represented.

A is the bodyof the still, having an upper section, AF, which I prefer to place immedi ately over the body or lower section, A, as shown in the drawing.

U is the boiler, provided with a'superheater, Y.

'G'isa steam-conducting pipe or manifold whose branches are connected with the supply ends of .theheating-coils within the still, and also with the exhaust-passages ofv the steam pumping-engines S and G" is awaste-steam manifold connected with the waste ends of the coils in the still.

D and D are respectively a steanrmanifold and a waste-manifold, ofwhich D is connected directly to the boiler, while the other terminates in a steam-trap of the ordinary construc tion, which, beingwell known, is not shown in the drawing". 1

Y is a superheater, which may be heated in any' convenient way, but which, from motives of economy, is best heated by the waste heat in the boiler-chimney. This superheater is connected with the exhaust-pipes of the pumps and with the heating-coils in the still,,and these pipes are also connected with each other, and are provided with suitable valves to shut off the superheater in case of necessity.

F is the supplementary still for removing the final remnant of gaseous ammonia from the weak ammonia when it is found necessary to re-enforce the liquor in the still.

G is a trap to condense and detain anyaqucous vapor that may be driven oil with the gaseous illlll'llOlllit. t v

H is the condenser,which is simply an outer vessel containing a pipe-coil surrounded by flowing water.

I is the anhydrous-ammonia receiver.

L is the interchanger for utilizing the heat of the hot weak ammonia as it passes to the absorber to heat the cold strong ammonia as it passes to the still.

M is an outer tank filled with a liquid noncongealable at the temperature which it is de sired to produce, and having within it tanks for the strong ammonia, surrounded by an absorb ing-coil, the non-conget-ilableliquidin thetank M being cooled by asecond coil, through which the spent ammonia-gas from the refrigerating or chilling coil contained in tank J passes.

K is the absorber, provided with coolingcoils, through which water or other cooling liquid can circulate.

R is the regulator to keep the aqua ammonia in the still A at the required height.

.S is a steam pumping-engine which draws thestrongammonia from its reservoir within a tank, M, and forces it to the top of the still.

T is a steam pumping-engine which forces the cooling-liquid surrounding the strong-ammonia receiver in M to circulate through the coils in theabsorber K when the water entering the said coils through pipe 24 is not sufficiently cold. r

In the operation of ammonia ice-machines heretofore one of two systems has been adopted. According to one system the ammoniagas is liberated by heat. from commercial aquaammonia of the strength of about 26 Baum, and a 'difiiculty arises, which is, that in warm climates and in summer, even in this country, the temperature of the available water used for cooling the condenser is too high to per .m'it the ammoniagas to reach a sufficientlyhightension to condense to the liquid condition without the employment of steam of high pressure'to liberate the ammonia gas from its aqueoussolution. According to the other system mechanical compressors are employed to compress the ammonia'gas to the tension required to permit itscondcnsation by the cooling-wateravailable for that purpose. To each of these methods there is the objection that they involve the consumption of a large amount ofv fuel, and of course are expensive.

I have discovered that the necessary tension of the animoniagas can be obtained without 7 the aid of mechanical compressors and with the use of only steam of low tension as a libcrating agent at any reasonable temperature of the cooling-water, by increasingthe strength of the aqua ammonia employedabove the strength of 26 Baum in about the proportion of one-third of a degree Baum foreach degree of rise of the temperature of the water (above about 55 Fahrenheit) used to cool thecondenser. The discovery of this principle enables meto make use of exhaust-steamers the liberating agent, and thus, by utilizing a waste product, rendering the production of ice or artificialcold very much cheaper. 1

The objtctio n to the use of exhaust-steam as the liberating agent in this class of apparatus is, that unless the cooling'water is at or below a temperature of about 55 Fahrenheit, the ammonia-gas from the aqua-anjimouia usually employed (say about 26 Baume) under the tension attainable by the use oi exhaust-steam (say the tension 01 about one hundred pounds to the square inch) will not condenseto the liquid condition. A proper increase above 26 Baume in the strength of the aqna-annnonia in the still completely overcomes this dii'i'iculty. and enables me to use stcanr of low tension, which has already accomplished mechanical \\'Qrk,'and which has hitherto been'discha rged into-the atmosphere without further useful service. I have also found that the exhauststeam from the steam pumping-engines re quired for various offices in the apparatussuch as pumping the aqua-ammonia from the strongammonia tank to the still, circulating the cooling-liquid around or in the absorber, pumping the cooling-water for the condenser when a natural flow cannot be obtained, and circulating thenon congealableliquid through the pipes in the rooms or "through the tanks .to be'cooledis suflicient inmany cases to liberate the ammonia-gas frointhe aqua-tun monia in the still. \Vhen the exhaust-steam from this source of supply is-not suflicient, it can be obtained as a waste product from other steam-engines which may be, in the vicinity, and when there is a failure of all these as sources of exhaust-steam, or when from any other causes it may be desirable to obtain a larger supply of heat for the still, steam can be taken to thefcoils ofthe still direct from a steam boiler or generator. I have further found it desirable to superheat the exhauststeam by passing it through any convenient form of superhater-such, for instance, as the one shown in the drawing. which con sists of a simple worm-coil. Though this superheater can be of any form, and may be heated in any manner, as a matter of prefercure I place it so as to be heated by the supertluous heat from the furnace used to heat the steam boiler or generator for supplying steam to the pumping-engines, and, thus further economize the heat. y

For the proper working of the above-described process it is necessary to provide somemeans to enable the liquid in the absorber to take up sufficient ammonia-gas to keep the strength of the aqua-ammonia up to v the working-point. The strengtliof the aquaammonia in the absorber is dependentupon two conditions+viz., the temperature of the absorber and the pressure of the ammonia-gas contained therein. Either oftheseelementscan: 1

to bt i a pressure in the second section of the absorber, and also by cooling both' sections of the absorber by one circulation, and in the case of the second section of the absorber by the spent gas from the expand- The details of vthe con;

ing or freezing coils. struction and operation of this absorber are more fully set forth in the specification of Letters Patent of the United States No. 836,233, dated February 26, 1886, and therefore I do not deem it necessary to'describe them herein. The

weak ammonia in the absorber will only absorb an amount of vapor due to the temperature and pressure therein, which is notenough to enable the exhaust-steam of 212 to create s'uflicient tension in the still to cause the ammonia-gas to liquefy in the condenser H when the cooling-water is above about 55 Fahrenheit temperature. With aquaanimonia of commercial strength ofabout 26 Baum-2l2 F111 renheit' heat will raise the pressure of the ammonia-gas in the still to aboutone hundred pounds. W'ith only one hundred pounds pressnr'e in the condenser and a temperatnreof about 55 Fahrenheit the am monia-gas will be condensed to a liquid and freezing-work can be performed; but when the cooling-water is materially above 55 Fahrenheit a higher pressure must be maintained in the still and condenser, and either steam of a higher tern perature than 212Fahrenheit or ammonia stronger than 26 Baum must be used; and in order to utilizethe exhaust-steam whenever water below about 55 temperature cannot be 7 obtained for condensation and for cooling the absorber I adopt the method of applying a medium cooled artificially to the absorber or by applying increased pressure in a section of the absorber, or both, as previously described;

-or I take a portion ofsteam directly from the boiler to'sonie of the heating-pipes arrangedin the still for that pnrpose,for I use two or more of these methods. At a temperature of Fahrenheit and atmospheric pressure wa-.

ter will absorb six hundred and seventyvolumes of ammonia-gas, and the resultingaqua-- ammonia will have a specific gravity of 0.875,

or about 31 Baum, and at the same temperature, with a pressure of two atmospheres, water will absorb about thirteen hundred volumes oi'ammonia-gas and have a specific grad ityofabout 0.825, orabout'41 Baum, and will at atmospheric pressure.

hundred and sixty pounds above the atmos.

boil at a temperature of about 10 Fahrenheit phere a temperature of 2l2 .will liberate ammoniagas and reduce the strength of am monia a temperature of 80 Fahrenheit in the condenser, a working margin of about 15 Baum, or three hundred volumes of gas.

In order to avoid carrying a higher pressure nia delivered by pipe 16.

At a pressure of one 7 in the absorber K, which determines the press are in the expandingor freezing coil, I use the absorber in two secti'onsthe .npper, K, of which israised-above the lower, P--and-I con ne'ct thc two byapipe, so as to obtain a column of mixed gas andliquid between'thetwmwhich increasesthe pressure in the absorbing-coil ot" the lower section of the absorber, and reduces the pressurein the upper section of the ab sorberr H The operation is asfollows: The steamboiler 'U or generator being put in operation, and the water therein being converted into steam of suitable tension to work the pumpjug-engines S and '1, say, into steam of seventy pounds pressure above the atmosphere, the reservoir in the tank M is charged with aqua-ammonia, and the pumpingengines are started and utilize the practical available mechanical force of the steam. The aqua-ammonia is pumped by the pumping-engine S from the said reservoir to the top of the upper section of the still, and the exhauststealn from the steam pumping-engines S and T is conducted through the superheater and the pipes into the heating-pipes in the body of the still. The aqua-ammonia pumped into the top of the still descends through the pans in the upper section of the still, is distributed upon the coils therein, and in its passage downward is heated by the inherenthcat of the superheated exhauststeam in the coils, and the ammonia-gas isliberated. The anr monia-gas ascending in the still passes off 0 through pipe 4 t0 the' trap G, where the gas leaves the vapor of water, which is mechanically mixed with it, and thence passes out through pipe 5 to the condenser H, in which theammonia-gas is condensed into anhydrous liquid ammonia, which is collected in the re ceiver Landis allowed to flow into the eX-' panding co'ls c'ontainedin J,whereit performs freezing work. The expanded gas is permitted to escape through pipe 10 into -lhe absorber K, where it is met by a spray of weak ammo- This weak ammoniais obtained from the still. It passes out of the still through pipe 14 into the regulator R, and thenee'by pipe 15 to and through the interchanger L, and thence through pipe 16 to the upper part of the primary absorber K. The gas and weak ammonia unite in K to form strong ammonia, and the'operation is completed in a secondary absorbing-coil in the tank M, to which the aqua-ammonia from K passes-by the connectingpipe 12. From this secondary absorber the strong ammonia en-" '7 tors the reservoir, which is also contained in M, whence it is drawn by the steam-pump S to go back to the top of the still on its cycle again. The strong ammonia, on its way to the top of the still, is passed through the coil of pipe in the interchangcr L, where it receives a preliminary heating from the weak ammonia, which is passed through the interchanger in the reverse direction, and as the ammonia 5 the steam'pumping-engines is not suflicient to' the required quantity ofammoniaam from the boiler is taken directly ttothe 'bodyof the still through the manifold i), and is admitted into the heating-coils conto nectedwith that manifold, in which case the ammonia is liberated-in part by the heat of the superheated-eXhaust-steam, and in part by the heatof steam taken directly from the boiler. In caseof any accide. rt to the super- 1 heater, it may be shut off, and'connection may be opened so that the exhaust-steam from the steam-engine passes dirrctly withoutbeing superheated to the heating-coils of the still.

When-the temperature of the available condeusing-water is too high to effect the condensation of the anhydrous ammonia at the pressure at which it is desirable to operate it, the aqua-ammonia in the still must be re en- ,forced. This may be done in several modes.

Thus, the secondary still may be charged with commercial aquaammonia, and the gaseous ammonia may be liberated from it by heat and conducted to the condenser; or anhydrous ammonia may be-introduced into the still, the

part of the apparatus into which the anhydrous ammonia is'preferably introduced being thereservoiriof the strong ammonia; or the weak aquaammonia in the bottom of the pri- 'mary still may be run into the secondary still and its aqueous ammonia may be liberated from it, while fresh commercial ammonia may be introduced into the primary still. By either of these proceedings the strength of the aqua o ened to the requisite extent for the temperature of the condensing-waterand for the pressure which it is expedient tdmaintain in the apparatus, as previously described.

- Having now fully described my invention,

5 what I claim, and desire to seizure by Letters Patent, isi I 1. The process, substantially as before set forth, of producing anhydrous liquid ammonia from aquaammonia by theheat of steam and pressure, which consistsin subjecting the aqua-ammonia under pressure to the heat of steam oflow tension and in increasing the strength of the aqua-ammonia as the pressure under which the ainmoniacal gas is liberated is increased.

3c sists in subjecting the aqujaammonia in condinement to the heat of steam,in cooling the f ammoniacal gas by water, andin increasing the strength of the aqua-ammonia as the tent perature of the cooling-water is increased.

3'. The process, substantially as before set forth, consisting of the following three operations, viz: first, the conversion of water into steam of a tension suitable for use ina steamengi-ne; second, the passage, of the steam through an engine, whereby the tension of the steam-is mainly utilizedfor the production of power, third, the passage of the spent or exhaust steam from the engine to the still,whereby the heat of the exhaust-steam is utilized for the separation of gas from the liquor in. said still.

4.. The process, 'siibstantially as before set forth, consisting of tions, viz: first, the conversion of water into the following four opera steam of a tension suitable for use in a steamengine; second, the passage of the steam through an engine, whereby the tension of the steam is mainly utilized for the production ofpower; third, the superheating of the exhauststeam from the engine; fourth, the passage of V the superheated cxhauststeam .to the still, whereby the inherent heat of the superheated exhaust-steam is utilized for the separation of gas from the liquor in said still. p

5. The combination, substantially as before set forth, of the 'steamgenerator, the steamengine, and the still by pipes which connect the steam-generator with the still through the intervention of the steam-engine, whereby the tension of the steam is mainly utilized in the said engine and the inherent heat of the exhaust-steam from said engincis utilized in the liberation of gas from the liquor in said still. 6. The combination, substantially as before set forth, of the steam-generator, the steamammonia in the apparatus may be strength:

engine, the superh ater, and the still by pipes,

whereby the. tension of the steam is mainly utilized inthe said engine and the inherent heat of the superheated exhaust-steam is utilized in the liberation of gas from the liquor in said still. Q

7. The combination, substantially as before set forth, of' the steam-generator, the steamengine, and the still by means of pipes which not only connect the said still with the steamgenerator through the intervention of the steam'engine, but also connect said still directly with said generator, whereby the contents of said still may be heated in part by the heat inherent in the exhaust-steam and 'in part by the heat of steam taken directly from the steamgenerator.

In witness whereof I have hereuntoset my hand this 15th day of April, A. D. 1886.

' ELI E. HENDRICK.

Vitnesses:

1 W. G. BUTTON,

E. S. MCDONALD.

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