High load self-cleaning helical spring filters

A self-cleaning helical spring filter in combination with a tubing string comprising,

• a. a vertically actuatable tubing string having an upper end, and a lower end extendable down into a well to a liquid-containing sand strata,
• b. helical spring means having a plurality of coaxial convolutions,
• c. helical grooved hollow elongated mandrel means in frictional contact with the internal surface of said spring menas conbolutions and connected to a lower end of said helical spring means,
• d. the pitch of said mandrel means grooves being opposite to the pitch of said spring means convolutions,
• e. said helical spring means having an upper end connected to said tubing string lower end for expanding the helical spring means,
• f. holes formed in said mandrel means grooves for providing, when said spring means is expanded, increased cleaning action, increased flow of production liquids through the helical spring filter, and increased resistance to lateral forces on the spring,
• g. perforated inner liner means for said mandrel means for limiting the maximum distance that said spring means may be expanded for backwashing cleaning liquids through the expanded spring for cleaning said spring means convolutions,
• h. said inner liner means comprises a perforated tube slideable axially and internally of said mandrel,
• i. an upper end of said slideable perforated tube being connected to the upper end of said helical spring means,
• j. a lower end of said slideable perforated tube having stop means for limiting the upward travel of both said tube and said upper end of said helical spring means.

A self-cleaning helical spring filter in combination with a tubing string comprising,

• a. a vertically actuatable tubing string extendable down into a petroliferou unconsolidated sand strata of an oil well,
• b. a helical spring having upper and lower ends, said lower end of said helical spring being fixed to said well adjacent to said petroliferous sand strata and said upper end of said helical spring being connected to said vertically actuatable tubing string for expanding said spring,
• c. a hollow perforated mandrel having two ends mounted in touching contact with the internal surface of said spring and one of said ends of hollow perforate mandrel being connected to said lower end of said spring,
• d. one of said mandrel ends being connected to said well adjacent to said petroliferous sand strata,
• e. said hollow mandrel having helical grooves in the outer surface thereof, the pitch of said helical grooves being opposite to the pitch of said helical spring, and
• f. said hollow mandrel having a plurality of spaced apart holes in each of said helical grooves for providing, when the spring is expanded, increased cleaning action for providing a greater amount of flow through the helical spring, the grooves, and the holes, and for providing high resistance to lateral forces.