Importance

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Abstract

Within a tubing string forming a conduit for a well is a rod string having sonically responsive impeller pump elements mounted thereon. The impeller pumps employ an elongated cylindrical structure which is spaced from the inner wall of the conduit to form an elongated annular liquid filled gap between the impeller and the conduit. The rod is sonically driven so that it vibrates resonantly. Valves are formed in the impeller, which in one embodiment may comprise a series of ball elements, in another, may comprise flexible reeds, these valve elements being opened and closed in response to the sonic energy to implement the pumping action, and in a third embodiment may comprise arcuate segments that are free to expand and contract radially in response to the sonic energy. The fluid annulus formed between the impeller and the conduit forms a fluid dynamic seal which effectively prevents leak-back flow past the impeller in view of the inertia provided by this annulus which effectively presents a large acoustic mass reactance to the sonic energy. Thus, such leak-back flow is prevented without the need for sealing engagement between the impeller and the conduit.

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First Claim