MORT’S FREEZING PROCESS.

Globe, Volume IV, Issue 386, 7 September 1875, Page 2

MORT’S FREEZING PROCESS.

A "Sydney correspondent of the Pastoral Times writes : The hope which, long deferred, is said to make the heart sick is peculiarly applicable to the experiments which have been going on for the last seven years at Sydney, at the expense of .Mr T. S. Mort, for the purpose, principally, of preserving meat by a freezing process for exportation to foreign parts, as well as for home consumption. A very large amount of time and money have been devoted by Mr Mort and his able assistant, Mr Nicolle, in these experiments. About five years ago it was by them believed that the experiments on land were so far conclusive as to justify them sending off for Great Britain a cargo of frozen fresh meat, consisting of beef and mutton. The “cold” was brought about by what is called the ammouiacal process, but just when all was ready to put the matter to a fair test at sea, it was found that, however much the system was to be controlled on land, there was great risk to be apprehended at sea. Mr Mort, with that humanity which has always been a prominent feature in his character, determined that he would not be the chief agent in incurring the risk of life under such circumstances. He therefore gave up the “high pressure” ammoniacal process, and went on experimenting until he has, as he thinks, so far overcome all difficulties and dangers, and he will very soon be in a position to start off a cargo of meat for England, which he is “satisfied will arrive there not only in a sound condition, hut that it will be as acceptable as the very best meat is in Australia. It is impossible to overrate the care that has been taken to perfect the arrangements in connection with this important matter, pregnant with the greatest results, as far as pastoral Australia is concerned ; indeed, Great Britain itself is also deeply interested in the success of the project. It is not expected that I should go al length into the subject in all its bearings—it would take far more space to do this than you can spare, but 1 shall give such information as I can vouch for the truth of.

Mr Mort’a elaborate ice making and meat fre zing establishment is placed at the head of Darling Harbor, Sydney, and immediately alongside of the new railway station for colonial produce. The buildings cover a great deal of ground, and are capable of considerable extension. Large as the buildings are, and extensive as is the machinery, they do not fairly give an idea of anything like the expense which Mr Mort has incurred. For about seven years he has, as stated, devoted himself to the elucidation of how best to send the surplus animal food of Australia to Europe and elsewhere, by means of artificial cold. Under the control of Mr Nicolle, the inventor of the plant of the Sydney Ice Company, and who is also the inventor and constructor of the great works I propose to describe, Mr Mort has made a succession of costly experiments, which have, for all practical purposes, been so much time and money thrown away, until the present machinery was devised. At least £30,000 to £40,000 have been spent on mere experiments, but failures on failures have not been able to turn Mr Mort from his determination to solve the problem. From first to last, the experiments at the works, at the head of Darling Harbor, and his works at the slaughtering place at Bowenfels, the outlay has been considerably over £IOO,OOO. All the freezing machinery is in duplicate, and occupies a large space. The material used is a strong solution of ammonia, which Mr Mort makes at a suitable establishment, from the waste liquor of the Sydney gasworks, Instead of freezing by the expansion of liquid ammonia, wholly freed from water—and which system requires the use of a compressing power from 1801 b to 2101 b per square Inch, according to the atmospheric temperature—the work is done by a strong solution of ammonia; that is ammonia not free from water, which necessitates no greater pressure at any time than 701 bto the square inch. This low pressure plan is a most important discovery, because under the old or high pressure system it was a most difficult thing to prevent leakage, to which was added the danger to be expected from the destructive effect of pure liquid ammonia on the various vessels, &c., inside which it operated. The steam machinery is capable of producing cold equal to 40 tons of ice a day, by an expenditure of about 1J tons of small coal, which means freezing upwards of 80 tons of meat a day, or over 260 fat bullocks. There is no noise from the machinery, and no smell of ammonia. Everything can be watched and regulated by one person. The gauges and regulating taps are all placed within the reach of one man, who can be seated while performing his duties. When in normal condition the pulsations of the vast machinery will be as regular as those of a healthy human heart. It would take up too much space to describe in detail the machinery and its actions, and your readers must therefore, for the present, be content to learn that it fully realises Mr Mort’s expectations, and that it far exceeds in power, in reference to the fuel used, any other artificial cold-producing machinery hitherto discovered.

That portion of the establishment which consists of rooms which are to be kept cold occupies the ground floor and upper floor of a building which is specially constructed to prevent the infiltration of heat when once the rooms are cooled. The walls of the building are sft thick, and within these outer shells are three spaces, the centre one of which is filled with coke, a bad conductor of heat, and the other two are air spaces, air without motion being, I believe, the best non-conductor known. The lower room, in which all the meat to be frozen hard is to be placed, is large enough to contain 600 bullocks hanging whole, or 3000 tons of meat close packed, and the upper room will hold almost as much. The ceiling of the lower room is covered with iron piping, which in aggregate length is over three miles. Through those pipes will flow a solution of chloride of calcium, which, having been cooled in the freezing column to 40deg below zero, or about 70deg below the freezing point, rapidly cools the air in the room and freezes the meat in it. The only entrance to the cooling rooms is from above through trapdoors. There is no natural circulation of air by which the cold can be abstracted. The hot air outside, being lighter than the cold air in the rooms, cannot enter in any appreciable quantity through the trap-doors while the meat is being let down to be frozen. When I visited the freezing room the temperature was two degrees below zero, and the ceiling was a mass of ice formed by the condensation of the moisture in the air, which thus was completely dry. The air being motionless, it was impossible to have conceived by the feeling that the temperature was so low. The people employed in this room suffer no ill effects from the cold. This lower or freezing room is to be lighted by the “magnetic light,” so that everything can be seen without heat being communicated by the lighting process. Arrangements, too, are completed for interchanging the stagnant atmosphere without the loss of much if any cold, and for abstracting the moisture of the fresh air before it enters. The stagnant air is drawn by an air-pump through thousands of pieces of copper netting enclosed in long wooden boxes. The copper netting allows the air to pass out, but retains all the cold until the fresh incoming air which has left its moisture in other wooden boxes containing chloride of calcium in lumps carries it back to the freezing room. In this room meat for exportation will be frozen and packed ready for shipment. As will be explained hereafter, it will cake only a small power to hold the meat in a frozen state, the main work having been done by the first process. The upper room, although separated from the lower one by a thick floor formed of non-conducting material, and although there was an open door at the end, showed a temperature as low as 32deg, or at freezing point. This cold was caused by thecoudition of the room below. When filled with meat this room can be reduced in temo perature by the same system as the otherr The upper room is primarily entrusted to preserve meat for local consumption, Mr Mort has nearly finished the slaughtering establishment on the Blue Mountains near Bowenfels. This work is also a large undertaking, where several hundred head of cattle or a relative number of sheep, can be killed every day. By killing the animals on the far-off side of the mountains, that part of the driving is avoided which so greatly deteriorates the quality of the meat used in Sydney; and Mr Mort hopes to make a profitable operation by supplying the retail butchers with better and more wholesome meat than they have hitherto been accustomed to provide for their customers. He has bad proper, though costly, meat railway trucks constructed. Each truck will

contain five tons of meat, which will be kept cool during the journey from Bowenfels to Sydney, by a mixture of ice and chloride of calcium placed in the hollow covering of the truck. The mixture forma an intensely cold mass, similar to that occasioned by a mixture of ice and common salt, only far colder. The meat for supplying the city will be exposed for sale in a suitable shed, and the portion unsold will be taken into the upper room, where the temperature of the meat will be kept at about 40deg. The meat intended for local use will never be frozen, but will keep fresh and sound for three or four weeks ; so, in hot weather, whatever meat the butchers may have on hand on Saturday nights can be sent to the cool room until the Monday mornings. This will save a great deal of animal rood now lost. The chloride of calcium which is to be mixed with the ice can be easily recovered by the evaporation of the water, and used over and over continually. Mr Mort is also arranging for large supplies of pure milk from the neighbourhood of Boural, where there is a great extent of the finest land in the world, and which is never subject to drought. He will be able to sell this milk to the retail vendors for 3d a quart, which is at a less rate than they can get it from the cows fed near to or in Sydney. He also purposes, as a principal part of his business, to provide the dealers in fish with that food, ready cleaned and scaled, fit for use. Tons of the finest fish can be caught on the coast near Illawarra, which by suitable arrangements will be delivered to the freezing room, from which it will be issued to the retailers. Consumers will be certain of the freshness of the fish, and as their servants will not have to clean them, the consumption will thus be largely increased. So, also, with butter and eggs, which, being purchased when cheapest, can be held fresh for any length of time, at an infinitesimal cost. To enable the meat placed on shipboard to be kept frozen, Mr Nicolle has invented a very simple machine, which can by no possibility be injured on the voyage. The principle of the machinery is the same as that of Mr Mort s domestic refrigerator. Cold is produced by dissolving nitrate of ammonia in an equal weight of water. A very low degree of cold can thus be attained, and the nitrate can be continually recovered by evaporating the water. The loss of ice on the voyage from Boston, in America, to Calcutta, is not more than one ton per day out of 500 tons. In 600 tons of frozen meat the cold will be equal to 200 tons, so that the daily loss on the voyage to Europe will not exceed half a ton per day. A small machine will provide the necessary cold, and it can be worked by the hand. No expensive fittings will be required in the ship, and one penny per pound will, it is found on careful consideration, be ample to pay all expenses, including freight, of the conveyance of the meat to London, The first lot of meat will be sent to New Caledonia. The Government there are satisfied that their necessities will be met by frozen meat, and consequently they will not give contracts for live meat for distant dates. It is to be hoped that Mr Mort will not only be successful in sending meat by his plan to Europe and elsewhere, but that his extraordinary perseverance and enterprise will be rewarded by a financial success corresponding with the risk which has incurred. At present Mr Mort is making five tons of ice a day, which will be collected into the freezing room for sale in the summer. Mr Nicolle has invented a plan of making ice, by which any kind of cold-producing machine will attain its theoretical capacity. No freezing machinery now makes more than 25 per cent ot its theoretical capacity. This part of the plan is not yet quite ready. The two gentlemen named —the capitalist, Mr Mort, and the practical chemist, Mr Nicolle—feel confident of success in all their grand projects. Mr Nicolle long ago offered to go to England in charge of a large cargo of meat frozen by his process, but his services could not in Australia be dispensed with. It is expected that within twelve months a satisfactory solution of the great experiment will be arrived at, and that Australian fresh meat will be sold in Great Britain side by side with the best beef of old England.