Cooling system

“ An embullient cooling system is one in which the coolant is circulated through the system by a temperature differential. Engine oil cooling is accomplished by a water cooled lubricating oil cooler which maintains the oil temperature below +190 degrees F during engine operation. Heat from the lubricating oil is absorbed by cooling water metered into the cooler by the lubricating oil cooler temperature control valve. The fuel supply for the engine is contained in underground storage tanks connected to a 55-gallon engine fuel tank. ”

“ The number i pumps of the primary and secondary cooling circuits are activated, using an external power source, to provide the required cooling for spacecraft equipment and cabin. The spacecraft radiator switch, located on the center panel, is placed in the BYPASS position so the cooling system coolant by-passes the radiators and is directed through the ground cooling heat exchanger.
Coolant is circulated through each coolant loop by a positive-displacement gear pump. Spacecraft 5, and 8 through 12 are provided with 2 pumps in each loop. Spacecraft 6 has only one pump in each loop. ”

“ The fluid flows from the supply tanks to the heat exchangers. The fluid temperature, when entering the heat exchangers is approximately -279°F for the oxygen and approximately -423°F for the hydrogen. The heat exchangers absorb heat from the recirculating coolant fluid of the spacecraft cooling system. This heat, applied to the high density fluid, raises the temperature of the reactants to approximately 50°F to 140°F.
The reactants, now in gaseous form, flow through the heat exchangers, past the high pressure relief valves and AGE temperature sensors, to the supply solenoid shutoff valves. ”

“ The requisite reduction of temperature is effected by apparatus similar to that described above in Wegelin & Hübner’s arrangement. The liquefied carbonic acid flows through a system of pipes fitted to the roof of the cooling chamber, producing170 by its vaporisation the necessary cooling and then it passes back to the refrigerating machine. Circulation of the air in the cooling chamber is provided for by a suitable ventilator under the pipes of the cooling system, gutters being fixed to carry away any water condensing upon their surface and prevent it from falling upon the chocolate. ”

“ The system is very efficient and we have no difficulty in cooling the water as low as 2° C. As a matter of fact our chief difficulty is in regulating the supply of brine so as not to freeze the water-supply.
Water-mixer.—If the valve b is opened, water flows through this short length of pipe much more rapidly than through the long coil, owing to the greater resistance of the cooling coil. In conducting these experiments the valve c is opened wide and by varying the amount to which the valve b is opened, the water is evenly and readily mixed. ”

“ The car has a perforated false bottom, to which is attached a powerful exhaust-fan system that sucks the heat out of the coffee. In large plants, [Pg 395] utilizing two or more floors, the tilting-type cooling car is favored. This car permits instant discharge through an opening in the floor into a receiving tank suspended from the ceiling below and connected with the stoning apparatus. Recently, a flexible-arm cooler has been invented that provides full fan suction to a cooler car at all points in its track travel from the roaster to the emptying position. ”

“ Besides the bother of keeping the water system supplied with water there is the danger of clogging the radiator with lime deposits, and in extremely cold weather the water is liable to freeze and burst the water jackets or the radiator; for this reason, air cooling is recommended by some for automobile engines. In certain air-cooled automobile engines the cylinders are air-jacketed; that is, they are surrounded with casings through which the air is sucked by a powerful fan driven by the engine shaft, so that the air is bound to flow if the engine is turning. ”

“ The dryer the fat the better, but it must not lay unduly long to drain. From this table they are passed through an Enterprise steam jacketed hasher for grinding. Steam is kept on the jacket to assist in rapidity in passing it through the hasher.
Cooling Water. —The chilling or cooling of water is accomplished in two ways, by the introduction of ice or the cooling of the water or by submerging pipes in the tanks, and circulating chilled brine or ammonia gas through the pipes, same being a part of the refrigerating system. ”

“ In buildings of the second class, such as residences, office buildings and hotels, we have been, as a rule, satisfied with sufficient heat, and have relied upon such ventilation as is secured by the natural circulation methods. In such buildings, therefore, the system of heating most used is that known as "direct radiation," in which radiators, or some form of radiating surface, are located in each room, and connected by an arrangement of piping to a central source of steam or hot-water supply. ”

“ Heating a coil beyond the required amount is of no consequence, provided it is not raised to such a degree of temperature that scales would form; and in all cases the interior must be swept clean of ashes, &c., when it is withdrawn from the fire. With respect to the modes of cooling during the process of shrinking, care must be taken to prevent a long coil or tube cooling simultaneously at both ends, for this would cause the middle portion to be drawn out to an undue state of longitudinal tension. ”

“ Similarly, fuels in hot coals and ashes can be moved, or the hot material can be scraped away to deprive them of heat.
Water is highly efficient as a cooling agent because of its great heat-absorbing capacity, in both liquid and vapor form. ”

“ Three-cutter tube shears, with worm gear motion.
Section 25.—CONDENSING AND COOLING APPLIANCES. Their uses generally are to condense steam, to cool heated gases, air, or articles of food requiring a low temperature; distilling, and other purposes. For cooling purposes, compressed air machines are in most demand. The air is compressed in a cylinder, then cooled to ordinary temperature again in a surface condenser, such as No. 468, and then expanded into the cooling chamber, through a cylinder and piston, the expansion reducing its temperature usually to 10° or 20° below zero. ”

“ 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. ”

“ With the perfect heat insulation obtaining, the heat production of the man would soon raise the temperature to an uncomfortable degree were there no provisions for withdrawing it. It is therefore necessary to cool the chamber and, as has been pointed out, the cooling is accomplished by passing a current of cold water through a heat-absorbing apparatus permanently installed in the interior of the chamber. The heat-absorber consists of a continuous copper pipe of 6 millimeters internal diameter and 10 millimeters external diameter. ”

“ Heat loss in buildings.—There have been considered in previous chapters the various kinds of radiators in use and the amount of heat given off by them under different conditions; and the subject now approaches a study of the particular way in which the heat is utilized. The object of any heating system is, of course, to maintain a uniform temperature in the building in question, and to do this it is necessary: First, to replace the heat lost by convection and radiation from the windows and walls of the building to the colder surroundings outside ”

“ The air thereby cooled has a lower capacity for the retention of water vapor, a function of its temperature; the colder the air the less water vapor it can take up. As long as the actual amount of water vapor in the air is less than that which the air can hold, no rain falls. But the cooling process tends constantly to bring the warm, moist, ascending air currents to the limit of their capacity for water vapor by diminishing the temperature. ”

“ Ships carrying perishables have the safety of their cargoes insured by a refrigerator plant. In all large cities there are ice manufactories using the same method, and of late even relatively small establishments, hotels, and apartment houses have their ice-machine. It seems probable that before long all such buildings and many private dwellings will be provided with a cooling apparatus as regularly as they are now equipped with a heating apparatus. ”

“ A series of battered cells in the radiator may reduce the number of cooling spaces that should be traversed by the water, and thus the hot water cannot be distributed over as great an air area as is necessary to maintain the motor at the proper temperature. ”

“ The hot water in the radiators cools and, in cooling, gives up its heat to the rooms and thus warms them.
In hot-water heating systems, fresh air is not brought to the rooms, for the radiators are closed pipes containing hot water. It is largely for this reason that thoughtful people are careful to raise windows at intervals. Some systems of hot-water heating secure ventilation by confining the radiators to the basement, to which cold air from outside is constantly admitted in such a way that it circulates over the radiators and becomes strongly heated. ”

“ A very heavy electric current is passed through the spot or area which it is desired to soften, so that, notwithstanding the rapid conduction of heat into the body of the plate, the metal is brought to a low red heat. In order that the spot shall not reharden, it is requisite that the rate of cooling shall be slower than when the heating current is cut off suddenly, the current therefore undergoes gradual diminution, under control of the operator. ”

“ As already pointed out, the combined effect will be nearly proportional to the excess of temperature in any given case provided that the excess is small, but it is not necessarily proportional to the extent of surface exposed except in the case of pure radiation. The rate of loss by convection and conduction varies greatly with the form of the surface, and, unless the enclosure is very large compared with the cooling body, the effect depends also on the size and form of the enclosure. Heat is necessarily communicated from the cooling body to the layer of gas in contact with it by conduction. ”

“ Conduction of heat is a commonplace occurrence in our daily lives, in industrial processes, and in nature. If a metal spoon is dipped in a cup of hot coffee, the spoon handle soon becomes warm and then hot—some of the heat in the coffee is conducted along the spoon. Heat from a burner on a stove is conducted through the bottom of utensils to cook food. In a steam engine or hot-water heating system, heat from burning fuel is transferred by conduction through the iron or steel of the boiler to heat water. ”

“ The usual method of cooling is to make the walls hollow and circulate water through them. This involves a pump, a quantity of water, and a “radiator” (cooling machine) so that the water can be used over and over again. To cool by air blowing over the surface of the cylinder is relatively ineffective: but has been made possible in automobiles by building fins on the cylinders so as to increase the amount of cooling surface. When the motors are worked at high capacity, or when two-cycle motors are used, the heat is generated so rapidly that this method of cooling is regarded as inapplicable. ”

“ Steam, however, gives up its heat to a relatively cool surface much more readily than do the hot furnace gases, and the positively circulated cooling water takes up that heat and keeps the temperature of the surface down, while in a boiler the absorption depends in a great measure upon the ability of the water by natural circulation to get into contact with the surface 314 and take up the heat by evaporization. It has been found, therefore, that a much smaller surface will suffice in a condenser than in the boilers which it serves. ”

“ As the impelling force of the air current will be the difference between the weight of the cool column of air in the downcast shaft and roads and the warm column in the upcast, the available force of natural ventilation and cooling will increase just as demanded, i.e., it will increase with the depth of the workings and the heat of the rocks. ”

“ The more thorough the cooling, the less moisture will the air contain to give trouble afterward by condensing in pipes or machinery. If a pressure higher than 100 pounds to the square inch is in request, a third compressor may be linked to the second. In some installations, where extreme pressures are attained, four-fold apparatus is employed; its chief economy rests in cooling the air at four distinct stages, greatly diminishing the work which otherwise would have to be wastefully done. ”

“ Any certain temperature causes a given piece of metal to expand to a certain size, or to contract on cooling to a different size. Some thermostats are made of a straight rod of metal like copper which expands more than iron when heated. The rod is so placed that when cool it will allow fuel like gas or oil to pass thru a pipe, and when heated, it will expand enough to close the pipe, shutting off the fuel. They are placed so that they close the pipe at the temperature desired for an oven or supply of hot water. ”