Ground water sampling device

A device for collecting a sample of a fluid in a stratum, comprising:

• (a) a casing;
• (b) a drive cone adapted for penetrating the stratum;
• (c) a screen having an interior, said screen adapted to allow passage of the fluid from the stratum to the interior when said screen is exposed to the fluid, said screen being fixedly attached to or adapted for fixed attachment to said drive cone, and said screen adapted to be removably placed inside said casing;
• (d) means for removably attaching said drive cone or said screen to said casing, wherein the force of said attaching means suffices to hold said screen fully within said casing when said device descends into the stratum, but wherein the force of said attaching means is insufficient to hold said screen fully within said casing when said casing is pulled upward through the stratum, whereby following such upward pulling of said casing said screen is withdrawn from said casing and is exposed to the stratum and to any fluid in the stratum;
• and
• (e) means for holding said screen to said casing after said screen has been withdrawn from said casing, the force of said holding means being sufficient to pull said screen and said drive cone upward through the stratum when said casing is pulled upward through the stratum;
• wherein the diameter of said drive cone is substantially the same as the diameter of said casing, permitting the device to be raised or lowered within the stratum after said screen has been exposed to the stratum and permitting the device to be used to collect a sample of fluid at a different depth within the stratum, without the necessity of first removing the device from the stratum.