. Cyclopedia of farm crops. Farm produce; Agriculture. Fig. 248. A commercial com cooker. bath, i. e., the filled cans definite period. (3) Steam under pressure. This method of steril- ization was introduced about 1870. The tempera- ture in this case may be varied by control of steam pressure. The steam being confined in the retorts, of course the pressure is equal within and without the cans ; thus, unless the outside pres- sure is removed suddenly, the strain on the cans is not great and loss from bursting is small. Most of the modern cans, however, are sutticiently strong to withstand sudde
. Cyclopedia of farm crops. Farm produce; Agriculture. Fig. 248. A commercial com cooker. bath, i. e., the filled cans definite period. (3) Steam under pressure. This method of steril- ization was introduced about 1870. The tempera- ture in this case may be varied by control of steam pressure. The steam being confined in the retorts, of course the pressure is equal within and without the cans ; thus, unless the outside pres- sure is removed suddenly, the strain on the cans is not great and loss from bursting is small. Most of the modern cans, however, are sutticiently strong to withstand sudden changes without injury. There are two modifications of the retort, known as the "wet retort" and the "dry ; In the former, the kettle is filled with water and steam under pressure blown in, so that the boiling-point of the water is much raised owing to the increased pressure. These kettles are generally cylindrical and are placed in a vertical position, with a heavy lid on the upper end. When in use, this lid is fast- ened down by means of heavy bolts. The kettles are generally provided with three valves,— an intake valve for steam at the bottom, an outlet for water at the bottom and an exhaust valve for steam in the lid. Although spoken of as a " wet retort," it can be used without water in the same way as a "dry ; In the " dry retort," the steam under pres- sure is blown in, directly replacing the air and coming directly into contact with the cans. The Portland type of retort consists of a heavy iron chest, about cubical in shape. One side of the cube is the door, which is hinged and fastens by bolts. With the exception of the door the retort is cast all in one piece, the door forming a separate casting. Both types of retorts are provided with ther- mometers and pressure gages. In the use of retorts of either kind it is that a current of steam under pressure be passed continuously, this "circu
Size: 1370px × 1824px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjectagriculture, bookyear
