Document wjQ30reLgvy1yg64OJdLVXm4

AMERICAN SOCIETY OF HEATING & YEMUAI1N6 ENGINEERSGUEE1923 TABLE 75. ' PROPERTIES OF VARIOUS FOOD PRODUCTS Substance COMPO5ITION Water Solids Specific Heat Above Freezing in Heat Units Specific Heat Below Freezing in Heat Units Latent Heat of Freezing in Heat Units Water........ . Lean BeefFat Beef.... Veal............ Fat Pork.... Eggs-......... Potatoes.... Cabbage.... Carrots...... Milk........... Oysters...... White Fish. Eels............ Lobster...... Pigeon....... Chicken_ Ice CreamWines........ 72.00 51.00 63.00 39.00 70.00 74.00 91.00 83.00 87.50 80.38 78.00 62.07 76.62 72.40 73.70 28.00 49.00 37.00 61.00 30.00 26.00 9.00 17.00 12.50 19.62 22.00 37.93 23.38 27.60 26.30 1.00 0.77 0.60 0.70 0.51 0.76 0.80 0.93 0.87 0.90 . 0.84 0.82 0.69 0.81 0.78 0.80 0.80 0.90 0.50 0.41 0.34 0.39 0.30 0.40 0.42 0.48 0.45 0.47 0.44 0.43 0.38 0.42 0.41 0.42 144 102 72 90 55 100 105 129 118 124 114 111 88 108 102 105 88 164 EXHAUST AND COLLECTING SYSTEMS PNEUMATIC exhaust and collecting systems may be classified in various ways. They may be classified by the economic purpose to be accomplished by the industries served, or by the type of system used. Classifying exhaust systems by industries served, they fall in sub divisions such as, metal working, woodworking, leather and shoe manu facturing, rubber industry, flint grinding, pottery works, pulverizing works, celluloid manufacturing, printing establishments, felt hatting and fur manufacturing, textile mills, grain and cereal industry, etc. ' TYPES OF SYSTEMS The type of exhaust system to be used is determined by the industry served, kind of material handled, and the work to be accomplished. There are two general arrangements; the central and the group systems. In the central system a single or double fan is located near the center of the shop with a piping system radiating to the various machines to be served. In the group system, which is sometimes employed where the machines to be served are widely scattered, small individual exhaust fans are located at the center of the machine groups. The group arrangement has the advantage of flexibility. It is, however, more difficult to balance than the central, and also the large number of small diameter trunk lines required show a much higher friction loss per foot of length than with the central system where one large main pipe serves a considerable number of machines. Exhaust systems are also characterized by the means employed to collect the dust or other material handled. The dust or refuse may be collected and controlled by enclosing hoods, open hoods, inward air leakage or general room exhaustion. With another class of machinery it is not feasible to closely hood the machines and in these cases open hoods over or adjacent to the machines are provided to collect as much of dust and fumes arising as. possible. In this class come such machines as rubber mills, package filling ma chinery, sand blast, crushers, forges, pickling tanks, melting furnaces, and the unloading points of various types of conveyors. The open hoods should be placed as close to the source of dust or fumes as possible with due regard to the movements of the operator. When the hood has to be placed at some distance above the machine it should be large enough to encompass an area of considerable extent as diffusion is usually quite rapid. Consideration must also be given to the natural movement of the fumes. For those that are lighter than air the- hood should be over or above the machine and where a heavy vapor or dust-laden air at ordinary Material for this section was prepared especially for The Guide 1023 by H. M. Nichols, Boston, Mass. 165