Cavins

This is an appeal from an interlocutory-decree in a suit brought by appellees charging infringement of patent ‘No. 1,917,211 issued to O. A. Cavins. The master found that claims 18 and 24 of the patent were valid and were infringed. The court sustained the finding, and entered an interlocutory decree for an injunction and an accounting.

Appellant contends that the patent is invalid because anticipated by previous patents, and that if valid the claims are limited to a narrow field by the prior art, by the nature of the invention, and by the specifications, and that thus construed there is no infringement.

The patent relates to a bailer for use in deep wells, particularly oil wells, for the purpose of removing sand and other debris from the bottom of the well. The bailer is of the type called a suction bailer or differential pressure bailer; the name being derived from the fact that the bailer is composed of two cylinders, one superimposed upon the other, separated by partition with a valve therein. On the bottom of the lower cylinder is a flap valve which is open while the bailer is descending so that the lower cylinder or chamber is filled with fluid under the hydrostatic…