450 



ELECTRICAL EQUIPMENT 



this purpose, and by this method from 360 to 1200 gallons of oil, 

 according to the size of the press, can be treated in an hour. 



The essential portions of the filter consist of a series of alternate 

 flat cast-iron plates and frames, the blotting paper being placed 

 between them, and the whole clamped tightly by means of a 

 large screw and lever at one end. Both plates and frames have 

 large cored holes in the lower corners, serving as inlet and outlet 

 for the oil. The surface of the plates, except for a one-half inch 

 rim round the edge, is grooved or corrugated both vertically and 



FIG. 283. Method of Using Oil Dryer and Filter to Dry Oil in a 

 Transformer as Installed. 



horizontally on both sides, forming the checkered or so-called 

 " pyramid " surface which supports the paper and forms channels 

 communicating with the outlet at the corners. This form of 

 surface is more efficient than a single set of corrugations or the 

 use of perforated metal. The oil enters at the lower left-hand 

 corner of the filter, passes through a series of cored holes in the 

 plates and frames and punched holes in the blotting paper and 

 enters and fills in parallel the chambers formed by the frames and 

 plates. It then passes through the blotting paper, along the 



