Refrigeration

“ Such concerns commonly supply ice used in car-icing. Mechanical refrigeration is beyond the means of many small retail dealers. Moreover, since decay in food, once begun, cannot be arrested by subsequent refrigeration, ice, or a substitute, is often essential on the farm. ”

“ In carrying out artificial refrigeration various kinds of machines are used for reducing temperature, in which the desired effect is produced either directly by the condensation and evaporation of suitable materials, such as liquid carbonic acid, ammonia, sulphurous acid, or indirectly by making saline solutions (calcium chloride) , cooled below the freezing point, circulate through a system of pipes fitted on the roof or walls of the space to be cooled. ”

“ In breweries, dairies, margarine factories, etc., refrigeration is of the utmost importance, and refrigerating machinery is used for cooling and drying the air blast for blast furnaces.
In some few places refrigerating machinery is used to cool buildings in warm weather and make life more bearable in summer weather. It is highly probable that refrigeration of dwellings will be more and more extensively developed. ”

“ Whereas, The important function of the process of refrigeration is enlarging and diversifying the supply of perishable foodstuffs, as applied in the preparation, transportation and distribution of these goods, thereby giving consumers a larger and more wholesome supply, preventing deterioration and waste, is recognized as being desirable and necessary ”

“ When the cooler is filled with warm meat and the doors are shut it is his duty to increase the refrigeration and see that the meat is brought down to the required temperature in the required time. It is apparent that the refrigerators should receive careful consideration, and be in charge of a man of reliability.
Beef should be placed in the cooler immediately after it is killed and never allowed to hang outside any longer than necessary. ”

“ It has been well said that "Necessity is the mother of invention." Cold storage of the present time is understood as "mechanical refrigeration," and in general, the preservation of perishable articles by means of low temperature, hence, the act of reducing the temperature of any body, or maintaining the same below the temperature of the atmosphere, is called refrigeration, or more familiarly known as cold storage, produced by the employment of machinery of various types. ”

“ One of these devices employs a gas jet, or lamp light, the heat from which, acting on a kettle filled with chemical compound, produces a low temperature for a small house refrigerator, while the same principle is claimed to be applicable on a larger scale.
The Uses of Artificial Refrigeration are numerous. For cooling and ventilating buildings, aiding in some lines of manufactures, and in chemical works, it has proved its usefulness. In all hot climates it is extensively employed for making ice. In breweries it is applied very extensively, and is practically indispensable. ”

“ We have learned how to pump heat and we can make heat vacuums, anywhere and at any time, even in the heart of the tropics, and regions in which no natural ice is ever obtainable have the benefits of refrigeration. Furthermore, we are not dependent upon ice for cooling foods. In many cases it is not necessary or even desirable to reduce temperatures to the freezing point of water. A moderate chilling is all that is required for certain foods. By the proper use of refrigerating machinery any degree of temperature may be obtained and maintained. ”

“ All of the above factors must be considered in the calculations for refrigerating requirements, and it is best to make allowances for a considerable factor of safety over and above the actual maximum, as well as for the economical operation of the plant. It never pays to crowd a plant to its limit or capacity. Guard against emergencies and possible abnormal demand for refrigeration by providing ample equipment. ”

“ No hard and fast rule can be adopted regarding the system of refrigeration to be adopted, whether by use of brine circulation or direct expansion. The case in hand and the nature of the business to be done seems to govern. For example, if the plant in which the business is [36] mixed, wherein hogs, cattle and sheep are killed, curing performed, and lard made, with a limited amount of freezing, brine circulation for general use would seem the better. ”

“ From these observations they infer that the law which has been promulgated for the refrigeration of bodies, cannot be strictly true: namely, that bodies part with heat in proportion as their temperature exceeds that of the surrounding medium. ”

“ Mechanical refrigeration, and this alone, has made it possible to properly cool meats for shipment to remote points as fresh meats, or to properly prepare them for curing, and to preserve them after curing beyond a comparatively limited time. Mechanical refrigeration made possible the equipping of ships for the transportation of meats under refrigeration from any point to any market on the globe. ”

“ In most cases, ice is available or electric refrigeration can be utilized for keeping cold milk, buttermilk, cider and other products available for immediate consumption for the hot and thirsty traveler in the summertime. Hot coffee or hot chocolate can be made available for service in colder weather. ”

“ One considered the greatest benefit for the purposes of refrigeration was to be derved from the use of the descending current, while the other saw more particularly the advantage of the ascending current ”

“ To prevent growth of micro-organisms in food and subsequent microbial spoilage, food must be kept out of the temperature range that allows growth. This is most commonly achieved by refrigerating or freezing. Refrigeration slows down or stops microbial spoilage. Freezing stops it completely.
EFFECT OF TEMPERATURE ON MICRO-ORGANISMS
Enzymatic activity, while slowed down by freezing, is not stopped in many vegetables and these enzymes must be destroyed by blanching the vegetables before freezing to prevent enzymatic deterioration. ”

“ We may conclude this brief glance at the science by mention of the very high temperature which the electric furnace has now placed at the command of chemists, and the equally great refrigeration now attainable, by which the air itself can easily be liquified and even frozen into a solid mass. ”

“ It would be the easiest thing in the world to attach a small room to the cellar or the kitchen, where a low temperature can be kept at all times, either by ice or by the artificial refrigeration that will soon be distributed and sold in the same way that gas, water, steam, electric light and power are now furnished in many cities. ”

“ This is of great convenience in calculating refrigeration required to cool and de-humidify air. For example, suppose it is required to find the refrigeration necessary to cool 1 lb. of air containing 98 grains of moisture and having a dry bulb temperature of 95 deg., to a final temperature of 40 deg. saturated. We find from the chart that the wet-bulb temperature is 75 deg. The total heat corresponding to a saturation temperature of 75 deg. is 37.8 B.t.u., while the total heat at 40 deg. is 15.3 B.t.u. The difference, 22.5 B.t.u. is the refrigeration required per pound of air. ”

“ Too often the refrigerator is neglected, milk and other food is spilt, filling the cracks, and slow decomposition sets in. A well-cared-for refrigerator is an important factor in the preservation of food, but when it is neglected, it becomes a source of contamination. Unclean vegetables and food receptacles, impure ice and foul air, are the most common forms of contamination. The [Pg 294] chemical changes which foods undergo during refrigeration are such as result in softening of the tissues. ”

“ Cooling Air and Water, producing low temperatures, making ice, cooling syrups and solutions, and separating salts from liquors by refrigeration. Pumps and Siphons, embracing every useful contrivance for raising and supplying water on a moderate scale, and moving corrosive, tenacious, and other liquids. Desiccating—air- and water-ovens, and other appliances for drying natural and artificial products. ”

“ Cold, even a freezing temperature, is not fatal to bacteria, but it does decidedly retard their growth. Even at the temperature of the ordinary refrigerator (about 10° C. or 40° F.) we find that most organisms multiply very slowly and as a result putrefactive changes are much retarded. Refrigeration is therefore a necessity for the proper keeping of foods, at least during the hot season. But to be efficient the refrigerator must be properly managed. Unless it be kept clean, properly ventilated and well supplied with ice it is practically useless, in fact absolutely dangerous. ”

“ The kitchen and its equipment will be equal to the best on the American continent. An especial refrigeration system will be installed and an ice plant added to furnish the hotel and station with artificial ice made from distilled water, sterilized by an effective method to provide pure drinking water for the guests. ”

“ Refrigeration. —This word covers the “bugbear” and the “solace” of the packers. No other one thing is of so much importance. Since the abolishment of the use of chemicals, such as borax, boracic acid, etc., as a preventive or retardant in the propagation of bacilli during the curing process, the packer’s sole dependence is refrigeration. ”

“ While refrigeration and cold-storage has been the chief factor in enabling the meat and other highly perishable foods to be imported, other steps, ensuring preservation of goods that are collected from farmers and brought together at shipping ports, are necessary to prevent decomposition prior to such goods coming into cold store. ”

“ Though, when the Glass, I imployed, was conveniently shap'd, as, like a Sugar-loaf, or with a long Neck, I found it not amiss to drink it out of that, without pouring it into any other; which can scarce be done without lessning the Coolness. The refrigeration, if the Glass-viall be convenient, is quickly perform'd: And if one have a mind to cool his hands; he may readily do it by applying them to the outside of the Vessel, that contains the refrigerating Mixture ”

“ It might only be supposed, that the refrigeration of the earth should be considerably increased, because we imagine that refrigeration is performed by the contact of the air, and that there is a great difference between the time of refrigeration in the air and in vacuo ”

“ Control of temperature of the food, heat or cool Control of the food’s acid content Control of moisture content of the food
The major method used for home preservation of food is temperature control. This includes canning with a pressure canner or a boiling water bath, blanching food before freezing, refrigerating food, and freezing it. Micro-organisms which cause disease and food spoilage are sensitive to environment temperature variations. By increasing the food’s temperature, micro-organisms are destroyed. When the temperature is decreased, their growth is inhibited. ”

“ Not enough use is made of cooling by evaporation by those who have not ice in the summer. Inexpensive and fairly effective refrigerators may be made, by any mechanic, of lattice-work sides covered with any thick fabric and kept moist, which would keep milk, butter, fruit, vegetables, and cooked meats in good condition if placed in a hallway with a good circulation of air, or in any shady place with good ventilation. ”

“ Now then, when we have the ice-making currents, what happens to the air of varying degrees of temperature? The coldest air is at the bottom of the refrigerator (of course we are always thinking of the best refrigerators) because cold air is heavier than warm air and the warm air rises. Therefore, if you have odorous things do not put them in the ice chamber because the air starting down will carry odors along. Put the odorous things and the things that should be kept coldest on the lower shelves. ”

“ If no foods that have not been reasonably cooled are put into the refrigerating box it is possible that the ice may last three or four days.
Aside from the efficiency of the insulation, the consumption of ice will depend largely upon the amount and temperature of the food in the other crocks and the frequency with which they are opened to the warm outside air; therefore chose [39] as cool a place as possible for the box to stand, and open it only when necessary. ”

“ The lack of ice of course causes much extra work and trouble in caring for food. Until now I never half appreciated a refrigerator; but, as Tom says, “We never miss the water till the well runs dry.” As our well is a spring, we hope we may be spared that calamity. This spring is near,—just at the end of the kitchen porch,—and yet the water for use must all be carried in. Less convenient, surely, than the turning of a faucet above the kitchen sink!
We have other trials and privations,—and compensations also. At home the vegetables we use are brought us from the markets. ”

“ THE REFRIGERATOR.--For home use, the refrigerator offers the most convenient means of keeping foods in good condition. As is well known, it is a device that, by means of air cooled by the melting of ice or in some other manner, keeps food at a temperature near the freezing point. All refrigerators are constructed in a similar manner, having two or more layers of wood between which is placed an insulating material, such as cork, asbestos, or mineral wool. ”

“ As long as the temperature of the goods stored is above the temperature of the room there will be a gentle draught around the mass of ice, and of course all the moisture in the air, vapors, and odors from the goods will condense on the ice and pass off, so that you can keep milk, cream, butter, fruits, and meats all in the same chamber without danger of injuring the flavor of either. The atmosphere of the room is always dry, sweet, and pure. ”

“ Foods so preserved are kept in cold storage. The cooling is accomplished by means of ice, or by a machine where compressed gas is cooled and then permitted to expand. Examples: meat, milk, butter, eggs, etc. ”