672 



Journal of Agriciilliire. Victorm. [10 Nov.. 1917. 



Several systems of piping are in use, each witli a number of strong advo- 

 cates, but all are alike in that they use in an 18 x 18 or 20 s 20 foot kiln, 

 175 to 250 feet of 8 or 10 inch pipe, disposed in a .series of loops or coils 

 beneath the kiln floor. The description which follows, if studied in 

 connexion with the diagrammatic sketches (Fig. XVI., A, B, C,) will 

 make the method of arrangement clear. The "single pipe system," in 

 which the piping makes one circuit about the room, is used where the 

 location of the building or the construction of the flues makes it impos- 

 sible to secure an ample draught. Tlie " double pipe system," in which 

 the pipe, after being carried around the walls, is brought back across the 

 floor before it passes into the flue, is used in kilns of large size or 

 wherever ample draught can be secured. The double pipe system is 

 preferable, since more of the heat is utilized, and its better distribution 

 to the floors results in more uniform drying than can be secured by the 

 single system. 



No matter what system of piping may be adopted, connexion with 

 the furnace collar is made by means of a section of special double thick- 

 ness Russia iron pipe, 10 inches in diameter. This is fitted with a T 

 joint, the whole standing erect and rising to about 4:^ feet below the kiln 



A 6 C 



Fig. XVI. — Systems of Piping which Increase Efficiency of Furnace. 



A., single-pipe system, used in small kilns, or when jacket-and-hopper con- 

 struotion is employed. B., double-pipe system, employed in large kilns or tunnels. 

 C, a still more efficient double-pipe system. 



floor. To the T, elbows are fitted, and two parallel lines of pipe 10 

 inches in diameter are led from these across the room to a point directly 

 opposite the chimney, and about 22 inches from the wall. These pipes 

 are given such an inclination as will bring them at this point to within 

 3-J- feet of the kiln floor ; a nearer approach would be dangerous, because 

 of the high temperature of the pipes. At this point elbows are fitted 

 on, and the two pipes are carried in opposite directions around the walls 

 of the room to the flue. Tn case the " single pipe system " is used, these 

 lines may be given sufficient upward inclination to bring them to within 

 24 to 30 inches of the floor at the flue, where the two pipes are united by 

 means of a T joint fitted with dampers, which enters the flue (Figure 

 XVI., A). If the double pipe system is to be used, the rise given the 

 pipe to this point must be more gradual, and the two lines, instead of 

 being united, are carried back and forth across the room in one of the 

 methods indicated in the diagrams (Figure XVI., B, C), with such 

 upward inclination as will bring them to the flue not less than 20 to 24 

 inches from the kiln floor. In the double pipe system, 10-in. or 9-in. pipe 



