Opinion ID: 403684
Heading Depth: 2
Heading Rank: 1

Heading: The Patents-Catching Junk

Text: 2 In July 1967, Baumstimler filed an application for a patent for an oil well clean-out tool. Patent No. 3,406,757 ('757 patent), issued on October 22, 1968, is for a hydrostatic tool used to remove sand and debris from wells. Hydrostatic tools for retrieving junk or undesired objects from the bottom of a well had been available for several years prior to Baumstimler's application for a patent. The basic principle upon which these tools operate involves inserting a hollow cylinder into the well until the cylinder is immersed in the well fluid. The cylinder contains a valve which controls the flow of fluid into the cylinder. The pressure of the fluid outside the cylinder is greater than that inside the cylinder. When the cylinder reaches the bottom of the well, the valve is opened and because of pressure differential, the fluid from the well moves into and through the cylinder, carrying debris, which is retained in the cylinder. The cylinder and debris are then extracted from the well. In layman's terms, the clean-out tool operates like a drinking straw. Thus if one inserted a straw into a drink with the hole covered by a finger and then removed the finger, fluid would flow into the straw. 3 The flow rate in these hydrostatic tools is a function of the pressure differential between the well hole fluid and the pressure inside the cylinder, as well as the diameters of the passages within the well clean-out tool. Should the fluid rush into the tool too rapidly, the tool moves upward from the bottom and fails to pick up all debris. To avoid this problem of fluid surge, the patently obvious answer is to slow the entry of the fluid. That result can be achieved in several ways. Previously existing tools had used a system of chokes (an area of reduced cross-sectional area to restrict flow) or water cushions (a layer of water inside the cylinder over the valve which increases the pressure above the valve and thereby decreases the pressure differential). Baumstimler's '757 patent reduced the surge of fluid by varying the diameter of the passage through the use of a donut shaped ring, or orifice, whose size could be adjusted. 2 4 Essentially, then, Baumstimler's patent, relying on prior art, added one new element, that of the orifice to control the flow. 5 In May 1969, Baumstimler received a second patent, Patent No. 3,446,283 ('283 patent), covering the same device as the '757 patent but altered so as to be capable of simultaneously cleaning a well and removing a down hole tool or plug. Down hole plugs have long been used in oil field operations to isolate sections of a well in order to perform processes to facilitate oil recovery. The process may generate sand and other debris which fall on top of the plug. Thus to remove the plug, the debris must also be cleared from the path of the plug retriever. The '283 patent, by attaching a clean-out tool to a plug retriever, both removes the debris and the plug in one trip. Baumstimler's inspiration for this invention was a Mr. Carter, who had called Baumstimler to a job site and asked him if he could adapt his clean-out tool so that a retrieving head could be screwed onto the tool. Baumstimler cut off the bottom-most portion of a clean-out tool, threaded its end, and screwed a Baker retrieving head onto it, completing the invention on that very day. 6 The '283 patent was a continuation-in-part of the '757 patent and thus its patentability was partially dependent on the patentability of the '757 clean-out tool.