Complete Text (Part 4)

stirring isrequired. The machine has come largely into use in perfumery. On the basis of his own experiments, Professor Meid- inger has formed a table showing the respective merits of various freezing mixtures. The table in the next - column contains the most serviceable. Salt mixtures give much greater lowering of temper- ature than simple salts, as they dissolve in much less water. Thus one part of sal-ammoniac is dissolved in three parts water, and lowers the temperature about 19°; saltpeter dissolves in six parts water, and lowers the temperature about 11°. (Compare the fourth and fifth on the list.) It will be seen that the salt-ice mixture proves considerably more energetic and cheap than any of the others, so far as use of the materials only once is concerned. The second mixture, too, cannot be re- stored; nor can the last, easily, on account of the crys- Mixture. . Cost in \ Marks. 1S 0.3400 0.12 .7 1.8) 1.010 0.6 3 |3 | t6wos 2.610 2.2 Tordinary salt, dice 3 eryat. | 31°10,74.1.91, 55 3010.70,1.20 42 | 51 wocd.as. 40 | | 2114.2 61] 2.5.25 joniac, peter, 4 (eat Glauber salt, 9 water. | Se perae a sO j * 4 2nitrate of ammonia, i sal moniac, 3 water. 3 sal ammoniac, 2 saitpeter, 10 1.810 1.6 tallized Glauber salt. Both are comparatively cheap, however. The mixture in which, by vaporization of the solution, the salt is easily renewed in its original con- dition, nitrate of ammonia and sal ammoniac, is so costly at the first that it would not do to use it only once. This was the mixture employed in an apparatus first ex- hibited by M. Charles at the Paris Exhibition in 1867. The tin vessel containing the substance to be frozen is inclosed in a large wooden vessel containing the freezing mixture, and is furnished with screw wings, which stir the mixture as the vessel is rotated. Another form is that of Toselli’s glaciére Italienne roulante. The cream or other such substance is enclosed in a conical-shaped vessel suspended in the freezing mixture, and the outer vessel, enveloped in cloth, isrolled to and fro on the table. None of these machines have found very extens- ive use. Large masses have to be operated with to obtain even small results, and the sum of operations must generally prove too troublesome in a private house. As to the question of manufacturing ice on a large scale by means of solution of salt, Professor Meidinger comes to the conclusion that by means of 1 kilog. of coal (for restitution of salt used) not more than 2 kilogs. of ice can be prepared; not to speak of the machine force required for transport of the large quantity of liquid. This is very unfavorable; an ammonia machine will give four or five times better results. Much improvement is, in the circumstances, hardly to be looked for. It would be necessary to find a salt that, in dissolving, gave a much greater lowering temperature than the mixtures known, and this cannot be expected, since all the known salts have been examined in reference to this point. The real cause of the small productions of such apparatus lies in the fact that restitution of the salt is effected only by change of aggregation (vaporization), and this involves large expenditure of heat. It may be mentioned that, according to experiments by M. Rudorff on cold produced by solution of twenty different salts, the two which gave the greatest lowering of tem- perature were sulphureted cyanide of ammonium, and sulphureted cyanide of potassium—105 parts of the former dissolved in 100 parts water produce a lowering of temperature of 31.2°; and 130 parts of the latter in 100 parts of water as much as 34.5°. —The Hygeia Ice Co., New Haven, Conn., has established a distilled water and ice agency at West Haven. —The Marion (Ohio) Ice and Cold Storage Co. are hav- ing a lucrative trade in distilled water, and are running one wagon for that trade exclusively. (Whitten for 1K AND REPRIGERATION.) NS o CONSERVATION OF MEATS. JULY, 1993. PRESERVING FRESH MEATS AS INVESTIGATED ON THE CONTINENT OF EUROPE —PARISIAN BUTCHERS COLD STORAGE—INSTAL- LATIONS OF COLD STORAGES, SECOND TYPE. By AvoustE J, Rossi, B. S.C. E. (Com ‘OTHER typical disposition is that of Mr. Velly, one of the principal wholesale butchers of Paris. The circulation of the air is obtained, as in the Schroeder system, without the use of any mechanical device, merely by the difference of specific gravity of the cold and warm air, the refrigerating room being likewise distinct from and immediately above the meat room; but the manner in which the air is cooled is characteristic. It makes of this installation a distinct type, and, for this reason, though of a comparatively secondary im- portance as to extent, it will serve as a good illustration of another example of continental practice. As in the cold storages of Geneva and Mulhouse, the freezing of the meats is avoided and the temperature maintained in the rooms is only of 2° to 4° C. (35° to 38° F.) The rooms can store thirteen to sixteen tons, 26,500 to 31,000 pounds of meat; their dimensions being thirty-nine feet long by twenty-one feet wide, by ten feet and six inches high; this gives, for the total ca- pacity, 8,600 cubic feet, passages included. Assuming, agreeing to the rule laid down by the commission in such cases, an amount of four pounds of meat per cubic foot of contents, $600 cubic feet multiplied by four pounds would give 34,400 pounds as the capacity in stored meats of the room; actually there are 27,000 to 31,000 pounds stored; and we are within the margin, with ample allowance for the facility of the service. The walls of the meat room are of stone, twenty inches thick. Ata distance of four inches from the stone wall, a brick wall, four inches thick, has been built, and the space between the two walls, filled with cork shavings. The brick walls, on their inside face in the storage, have been cemented to a height of about six feet all ied from May number, page 370.) «. ICE .. AND .. REFRIGERATION .°. 13 around, and, in order to admit of a thorough washing, the floors have been asphalted The number of windows has been reduced to the minimum consistent with the necessities of light for the service; and are made of three glass sashes to avoid, as much as possible, the loss of cold on this score. The ceilings are made of brick arches and iron I beams, covered, first, with 4 layer of six inches of cork shav- ings, then with one of clinkers or cinders, four inches thick; over this is applied a bed of concrete, made with clinkers, four inches thick; and the whole has received a thick coating of asphalt. Ventilator shafts 7 7, open- ing on the roof, and provided with registers inside to regulate their action, permit the introduction of fresh air or evacuation of the vitiated air, whenever it is con- sidered advisable. Immediately above the cool room #’ is the refriger- ating room X&. It extends in the whole length of the storage, but covers only a part of it in the width, some ten feet or thereabout. Instead of the troughs and of the spray of brine resorted to at the Mulhouse and Geneva markets to cool the air, a system of coil pipes, very much like the refrigerator or expander of an ice ma- chine, has been used for the purpose. In this coil culates the brine, made cold in separate tanks in a special part of the building devoted to the machinery by the action of the refrigerating machine. There are, in fact, two distinct systems of coils (see plan, Fig. 3; section 4 #, Fig. 2), at a certain distance from but communicating with each other, the circulation of the brine being continuous from one to the other, their total length is about 2,000 feet. This disposition facilitates the repairs in case of need, as well as the cleaning of the surfaces. The circulating brine is cooled to such a temperature as may be found proper to obtain the necessary cooling of the amount of air which comes in contact with the piping. In this case, the temperature of the brine is --10° C. (14° F.). Particular care has been taken to thoroughly insulate this refrigerating room 7. The sides are made of two wooden partitions, built with tongued and grooved pine boards, ten inches apart, the space between them hav- ing been filled with cork shavings, or such other appro- priate insulating materials: the ceiling has been insulated in the same manner, and, on the upper boarding, under the roof proper, a thick layer of cork shavings has been spread loose all over. The floor which forms the ceiling of the meat room has been constructed as already de- scribed. The circulation of the air is induced by the 14 «. ICE... AND .. REFRIGERATION .°. JULY, 1993. difference in the specific gravities, as in the first type. The air, cooled by its contact with the cold pipes of the coils, in the interior of which circulates the cold brine and on the surface of which it deposits as frost the moisture and the germs with which it may have charged itself, becomes heavier; it descends through the five central flues F, constructed in the floor in the meat room, circulating freely around the meats placed in proper compartments or stalls, thereby getting warmed up and saturated with moisture at the expense of the watery con- stituents of the meats, and becoming thereby lighter, ascends by the lateral flues C C C to the refrigerating room, to be there cooled again and deprived of moisture before it returns to the storage rooms. The velocity of the current is very frost for the purpose of cooling, while at the same time getting rid of it. Instead of the brine being used as the agent of refrigeration in the coils, it is obvious that there could not be any objections to expanding directly the volatile liquid in the coil itself, as it is done in cellars of breweries by certain systems of ice machines, preserving at the same time the other characteristic features of this type. We may make here a remark in passing, that the lower the temperature at which the air will have to be circulated around the meats, —and in the case of the con- gelation of the latter it has to be very low and greater unless some remedy be afforded,—the greater will be fig. necessarily very small, thus in- suring a thorough and gradual H cooling and desiccation of the L tissues—conditions important, it | is stated, to obtain the most satis- | factory results. | | The figures 1, 2, 3 show the jl. L general arrangement of the dif- erent rooms and relieve us from any lengthy description. We < intend to present only such de- tails as may be more character- istic of this system. It is obvious that, with such a coil, the moist- ure of the air must be condensed in the state of frost on the sur- face of the iron pipes, and that this frost, increasing in thickness as the operation proceeds, acts as anon-conducting substance to diminish the transmission of cold from the brine to the air, thus requiring from the machine a greater production of cold than would be necessary to insure a given result in a given time. In ° this particular case, the refrig- erating machine being ample for the service and not working con- stantly, time could be taken to thaw out the condensed moisture which is collected in a proper gutter placed immediately under the coil, the resulting water being drawn off by a special pipe. The floor being asphalted and slanting, any drippings which might chance to fall on it could also be readily disposed of. But there are some cases when the machine may be required to work day and night and continuously for several days. A special disposition has been adopted in this cold storage in view of such possible eventualities. By a special device and the working of two cocks the brine can be evacuated and the frost thawed out, it is said, in less than ten minutes of time. The fact remains, however, that the ice machine has accumulated this frost on the pipes to no useful purpose; rather, the contrary. We will have to speak further, in describing a third type of cold storage, of a contrivance intended to utilize this F FI at des * These figures aud the following are taken from "Genie Civil.” vey) aed Savage, Rais the objection to the condensation of the moisture as frost on thecold metallic surfaces as taxing unduly the refrig- erating machine. In the Schroeder system this is avoided, but the system may present objections of another kind on which we will not insist at this stage of our ex- amination. We should not forget to mention that in all the cold storages we have described, as well as in those which follow, the refrigerating machines used are all of the class in which the mechanical exhaustion and com- pression of the vapors of a volatile liquid is resorted to as the agent for the production of cold. A cold storage of the same type has been erected at Tunis. In certain seasons the temperature of the air there remains during the day between 40° and 50° C. (104° and 122° F.), not going below 30° C. (86° F.) dur- JULY, uns. ing the night! The cold storage has two stories; one, a basemegt, is r s. The meat room is on the first floor. The steam rved for fish room and cellars for wines It can and be store 22,000 pounds or eleven tons of meat. engine has a power of 50-horse power, and the ice and hinea capacity of 14,000 thermal units is made by the ma- As this cold stor- refrigerating ma per hour. A certain amount of ice chine, and finds there a ready sale. ny special feature, we will limit age does not present ourselves to this simple mention, inserting only on this point: ©The temperature in the storage rooms is main. tained above freezing point.” YHIRD TYE That which distinguishes this class of cold storages, and makes of it a special type perfectly distinct from the two others, is: /irst, That the circulation of the air in the meat rooms is obtained artificially by a me- chanical device, a blower, instead of being produced naturally by the difference in the specific gravity of air at different temperatures. ‘ond, Though the air be cooled, as in the second type, by contact with metallic sur faces, the mode of cooling these surfaces is essentially characteristic; the brine is dispensed with, and recourse has been had to the direct expansion of the volatile liquid itself in the coils as the agent for production of cold. frigerator” in the system of ice machines in which brine is used as an intermediary mode of transmission of cold; in other words, it represents the pipe system of a cellar in which ammonia is directly expanded, with this differ- ence, that the cooling operation takes place in a separ- ate room and not inthe meat room itself. 7/ird, Finally, in all the installations of this type a special arrangement of this direct expander, or air cooler, has been adopted, by means of which the objections resulting from the con- densation of the moisture as frost on the cold pipes are obviated. We will first make a cursory review of a few cold storages of this kind on the Continent, reserving for the last the most important of all, which we will choose as a model of the type, illustrating its principal dispositions by figures, before proceeding to describe, - with some details, this system of special air cooler in which the formation of the frost on the pipes is taken advantage of to contribute to the cooling of the air, at the same time getting rid of the frost itself. At Lisbon the cold storage has been established in an old powder house, the walls being forty-two inches thick, insuring, of course, all the insulation desired. In Portugal fish forms the basis of the alimentation of a certain class of the population, and fishing one of the na- tional industries. The introduction of cold storage for the preservation of this article of consumption has been a source of wealth for the country. sh, thus preserved, have been transported in refrigerating cars to the markets of Madrid, a transit of twenty-four hours, without being ‘‘beheadcd,” a practice which was rendered necessary previous to the use of artificial re- frigerators on account of their unsightly appearance. ««Fish suffer less from congelation than meat does, " as far, at least, as retaining its palatable qualities, says Mr. Tellier; but it cannot be preserved for such long periods as meat for two reasons: Firsf, the eye dries up and loses its shining appearance after too long an exposure to cold. Second, if frozen, the skin, being less elastic, gets hard and is detached from the flesh. The air cooler corresponds, in fact, to the ‘‘re- «. ICE .. AND .*. REFRIGERATION .°. 15 But if the lowering of temperature is limited to 34° F.," or thereabout, and the time of preservation reduced s, “both the merchantable quality and appearance of the fish are retained.” At Lisbon the cold to about three we storage is established on the principles of the third type. y by ns of a blower, the temperature in the room not being allowed to reach below 32° F, At Brussels the cold rooms are constructed below the market, in