The Philadelphia Diamond Grid Battery
Old Type
Figs. 254 and 255 show the construction of the old type Philadelphia Diamond Grid. Battery. Figs. 254 and 256 show the diamond shaped grid from which the battery derives its name. It is claimed that this construction gives a very strong grid, holding the active materials firmly in place, and giving a large amount of contact surface between the grid and the active material.
Figs. 254 and 255 show the old type battery, and give the details of the cover, terminal posts, vent plug, and so on. The post seal is made tight by pouring the compound into the cover well so that it flows in around all of the petticoats on the post.
This construction increases the distance that the acid must travel along the post, in order to cause a leak, about two and one-half times the vertical distance on a smooth post. The hard rubber washer which fits around the post acts as a lock to prevent the post from turning. This applies especially to the two terminal posts to which the cables are attached. The washer is intended to prevent any strain in the cable from turning the post and breaking the seal between the post and the compound.