The Bridgeport evening farmer., 1914-04-22

btain refrigerator cars are much more efficient than others, and their dncreas-
 ed efficiency sappar ently results from E their construction.
 The insulation of the car in relation
 to temperature is it's most vulnerable
 part.t with the character or the Ice bunker next in Importance. In the
 past the insulation has not been sHf- ficfently heavy to maintain the low temperatures produced by the refriB- lferant. and the bunker has not been SD built as to distribute its refrigerating effect evenly throughout the car This last was fully established by the use of thermographs and the electric re- Of the car. The use of a dead air space in cars is not found to be suc- lcessful. Cork, the best known instla- tor, which is almost ifnpervious to wa ter and contains practically no nitro- genous material which might produce i decay. has not been used to any great extent in car construction. A Wool and hair felt arc good insulators, but
 their high percentage of nitrogenous 1 material makes them good bacterial media when moist. Th89es materials when once moist seldom dry out, and ] the resule is putrefaction. giving rise to offensive odors, which cpntaninato goods. Some of the vegetable or cell lulose fiber insulators are perhaps slightly more resistant to moisture and bacterial action. but in time they also become moist, and the alkalies present in such material hasten their chemical decomposition. It is for this reason that car builders are exert l ing every effort to prevent moisture from reaching the insulation. Min eral wool is least subject to decay, but on the other hands it's non-adhesive qualities hinder the naanufacture Of strong material r The insulation in the side walls and floors Of the cars used by six different lines shows no radical difference in quality or quantity, though methods of construction in certain cases are preferable. The roof of the car the- oretica11y is most severely taxed to prevent transmission of heat. The most efficient cars studied were those with the best insulated and best built roofs. More attention should be paid to roof and floor insulation. and the floor should be built with its fnsu- lation more effectively protected against moisture.
 The wire-bas1<es pfincipIe Of ice bunker is sound because abundant air access to ice and salt results in in- creased efficiency. A serious short coming to the present type Of cars is the impossibility of equa1fzing the temperature at the center and at the bunker so. that all parts Of the car are sufficiently cold. Good bunkers and any additional insulation. toseth- CT with the slowing of the load so as to 4pfovide passages for cold air be- tween packages, should materially help to improve results. The well- cooled package does not show chan ges In tenpera t1lre corresponding to those in the air of the car. but a long coutinued increase of te1nperature or direct contact between the package and the wall of the car, and therefore. the source of heat, affects the goods in the course of time The daily rise and nightly fall of temperature in the car sometimes result in slight chan ges in the packages, but it is the con- stant or maintained rise in the aver age temperature of the car that is responsible for objectionable results noted at the expir ation of long hau1s