CHAMBERS' SYSTEM OF COOLING AIR FOR THE PRESERVATION OF MEAT. [From Iron.]

Waikato Times, Volume XXV, Issue 2071, 15 October 1885, Page 4

CHAMBERS' SYSTEM OF COOLING AIR FOR THE PRESERVATION OF MEAT. [From Iron.]

Since the year 18S2, when Letters Patent were issued to John Clumbers, run-holder, of Te Mata, Napier, New Zealand, " for improvements in refi iterating and froe7ing and in app.uatus employed for such purposes-," it has been ail open secret to those most mteipsted m the frozen meat tr.idc that tho desideiatuni of a less expensive ptoCL'-s tli.m those adopted by ll.iil.im, I >ell Colein.in and other-, would shoitly be secured to the public. Tho delays which ha\e taken place in peifecting the expeinnental machine ha\e in no way shaken confidence in the principle adopted by Mr Chambers, and wo aie now able to state as the results of the final tests winch have been applied to the machine at the insulated chambers of the London and St. Katharine Docks Com piny, that the anticipated advantages of tlio adoption of the nmmonu process in combination with Mr Chambeis' invention, over whit has hitherto been called the "cold air process," have been fully realised. Mr Chamber-, claimed to produce by this ammonia machine and his cooler, cold air for lefngeiating purposes at a cost of onefouith of that of machine* now used on the cold an compression system, for an equal lefugciating effect in the cold stores. It has long been known that much more ccrinomic.il les-iilts, in the direction of pioihiOinj? cold, could be secured by the eva poi.itum of volatile liquids in v.icuoaudthe condensation of their vapour by the combined action of cooling water and pipssiirc, md the continued re-ovapoi ition and recondens ition of these same \olatile liquids, tlnn by any other means, but although this piocess has been .successfully applied on .in extensive scale to the aitihcul production of ice by such men as Cane", Recce, Lmd*s, I'ictet and others, and expcits have endeavoured to apply the sanio principle to the pioduction of cold air, it has remained for an amateur to discover a successful modus operandi. Mr Chambers' engineering faculties — natmallyof a high order— weie especially stimulated by the motne of securing for himself and fellow colonists, as huge pro- j duceii of stock, the most advantageous mean-, of disposing of their produce. He would not believe that the systems of refugeration which had been applied so effectually and economically to the production of ice, could not be applied to the pioduction of cold an, in consequence of the mechanical difficulties being insurmountable, and he accordingly devoted himself for yeii s to tho perfecting of the air cooling appiratus which now beais his name. As tho nature of Mr Ch.unbeis 1 invention is generally misunderstood, it is important to know that ho apparatus is not a machine for producing refugerating effect, but one foi applying the effect pioduced by ammonia, sulphurous anhydride, ether and othei similar machines, to the cooling and diyinjf of air, a feat which has not lntheito been successfully accomplished, so that an ordinal y ammonia, icy-making machine with a " Chambers' cooler " attached, may now bo utilised for tho dual purpose of making ice for commercial purposes, and for freezing and piescrving meat. The cost of coal is the chief Insis of comparison for all systems of refrigeration, and the measuro of results may be roughly stated in negative therm »1 units -the unit being the amount of boat necp*«n>y to change tho temperature of onn pound of water one degreo by the Faliieuhcit thermomctric .system. Thus, theoretically, it has been computed that the maximum cooling effect obtainable from the expenditure of one pound of steam fiom — Air, by tho compression and expansion system, winch is the favourite one now in me, is . 127 thermal units Kthei, by compression . 244 „ „ Sulphurous Anhydride 370 „ „ Ammonia, by the absorption hystem 594 „ „ Ammonia, by the compression system 978 „ „ The maximum theoretical effect being so much in favour of .ammonia by the compression system, it is evident that the ammonia machine is the one which theoretically ought to show the best result-, m connection wirh the Chambers' Cooler, and hence it was the one chosen by Mr Chambers for piactieal expeiiment. But although theoretically the ammonia compression machine may show an efficiency about7j times gioater than air and as an ice machine is no doubt 7 or 8 times as efficient, yet when working at temperatuics lunch lower than those necessary for making ice (as is the e.iso for cooling an for stores) ko found that the ratio of pfhciency fell short of the theoretical difference. The main point, therefore, to tho public is not which is theoretically the best lefngerating machine, but which is practically the bfst. The value of alb of steam is not so intelligible to most people as a lb of coal, so the following set of figmes has been prepared Knowing tho number of negative thermal units that are practically produced from the combustion of 1 lb of coal by the above systems when working at such temperatures as are applicable to the cooling of air for cold stores. The figures for the air system aro based on one of the existing Hasl.un machines and give that maker full credit— those for the ammonia compression system, are based on the results of the ammonia machine with the Chambers' Cooler already referied to. It is cuuous that the figuies should come out exactly four times greater, and one would suppose that they were mad a to accommodate one another, but, as a matter of fact, they aiisc bona hde from the data given. Thus prictically tho maximum conlincr effect obtainable from the expenditure of 1 lb of coal is from — Air 3">7 thermal unit*. Ether by compression 803 do. Sulphurous Anhydride 1,071 do. Ammonia by the absorption system 1,249 do. Ammonia by the com-pies-ion system 1,428 do. The machine now on exhibition at tho B Jetty Victoria Dock, of the London and St Kathonno Docks Company, consists of two duplicate vertical compound steam engines, with one surface condeusei common to both, and two pails of duplicate single acting ammonia compression pump*, with two separate and independent crank shafts, two air pumps, one water cnculating and one brine pump, one amnionn condenser, one .ammonia rcf i Jgcrator, and one Chambers' patent aii-cooling ap paratus. It is constructed fm u*e on boaid ship or •teamer, and is of power equivalent lo pro during 12 tons of ice per day. Being donblo in its puncipal parts, it may be worked by either engine at full power or by both engines each at half power, an anangement v\hich will be of great use in case of accident, and which may be regarded as an insurance against the risk of " break-down."' The ammonia machine and tho " cooler ' stand in an aiea of 30(5 superficial feet, and occupy a space of 2,2'J.l cubic feet. It is calculated to maintain at an aveiagc temperature of 13 degrees, 1,023 tons of measurement space equal to 4f>4 tons of mutton. Tho quantity of cold air delivered at zero is 4,390 cubic feet per minute. The indicated horse power in the tropics will be 35, and the coal consumed 1 ton 2 cwt per day of 24 hours. In temperate latitudes the powei would be reduced to 27 horse, and the consump tion of coal to 17J cwt per 21 horns. The average consumption for a voyage through the tropic* would be one ton per 24 hours. The Cooler," which is the subject of the patent, may be described as a cast iron bottom air-box, with four partitions, on which are secured four gun-metal tubw plates, each drilled to receive the lower ends of 240 copper U tubes. Slides in cast-iron fiames are fitted into openings in the c«st-iron box for the purpose, when necessary, of roveiwng the current of air which pasies througTi the U tubes. The frigerating liquid of brino cnculates round these U tubes, and tho principle of the patent consjits in lemoung the greater part of the moistuie from the air by con densation into water befoie the freezing point is reached in the passage of the an thrjugh the tubes. The water thus wiung out of the air is thus deposited in the bottom of the iron boy, and flow s out in a stream thiough cocks provided for the purpose, a« long as the air fiom outsidn i» passed through tho tubes. In practice this only occurs for a short period, foi ns soon as the insulated space is filled with c«ld air, the machine draws its supply fiom tho cold chamber, and utihsei tho same air over and over agnin. Any portion of the watrry vapour which may be deposited in tho tubes in the shape -if snow oi ice is removed by roveming the current of air, and tho absenco of snow from the channels of communication be-

twoen tho coolers and the insulated chambers is one of tho claims rained by the in' ventor of the superiority of his proecfia over any other existing procrs«. Other advantages claimed by the inventor are that tho inuubted chambers are entuely free from fog, and the air used for cooling them is not impregnated w ith lubricating maten.il and rendered impure, which is un.-woidablo by the "cold air" ploCPhs. The popular prejudices against the mo of ammnn'.i for refrigerating machines aro — 1. That the vapour of ammonia, is explosue. 2. That in the event of accident, the £ttffoc.itiug nature of the \apour would be dangerous to life. 3. That by reason of the high pressures at which the machine works, especially in hot climate*, it would be difficnlt to keep the joints gastight. All of which appear to be prejudices, and nothing more, for the following reasons :— 1. Tho \apour of ammonia ii not explosive, except at temperatures, which never come within the sphere of practical experience in tho process of refrigeration. Under ordinary condition* it will extinguish fire. 2. The \apour is not more suffocating than coal gas. 3. The difficulty of kocping the joints tight under high pressure is simply a mechanical one, and has already been thoroughly overcome. In tho semi-tropical towns of the American continent, such as New Orlenns, Cincinnati, and other Southern cities, numbers of ammonia refrigerating machines for ice making and brewing purposes are in daily successful usa, and fioin their groat economy of working are superseding all other kinds. The engineer under whose superintendence the machine and cooler have been perfected is Mr W. H. Beck, 113, Cannonstreet, London, X C.