The Philadelphia Separator
The Philadelphia separator is made of quarter sawed hardwood. It has a hard resinous wood in which the hard and soft portions occur in regular alternating vertical layers. The soft layers are porous, and permit the diffusion of the acid from plate to plate. The hard layers give the separator stiffness and long life. The alternating hard and soft layers are at right angles to the surface of the separator, so that the electrolyte has a direct path between plates.
The methods of repairing Philadelphia Diamond Grid batteries are no different from those already given, on pages 328 to 374.
When the elements of the old type batteries have been assembled and returned to the jars, put the covers in place, and pour the compound around the edges of the cover, and in the post wells. The old compound must be removed from the petticoats on the posts before new compound is poured in. The compound must be warm and thin enough to flow around and fill up the petticoat spaces on the posts in order to get a good seal. When the post wells are full of compound, and while compound is still warm, put on the square sealing washers and press them down so that the holes in the washers fit closely around the octagonal part of the posts.