Ground water sampling device

A ground water sampling device adapted to be driven into the ground at the lower end of a probe rod string, comprising:

• an elongated one piece cylindrical hollow housing having a wall thickness and having an inner surface defining an inner bore and an opening on its lower end, an upper end of said housing adapted to be attached to a probe rod string, said bore having a primary diameter section transitioning to a reduced diameter section, said reduced diameter section formed into said housing adjacent the lower end of said housing, said inner surface of said housing having an annular shoulder sloping downwardly and inwardly from said primary diameter section to said reduced diameter section, said wall thickness of said housing being substantially uniform throughout said annular shoulder;
• an elongated hollow screen telescopically received within said one piece housing and capable of being placed in a stowed position completely within said housing during driving of the device into the ground so that said screen is substantially isolated from the driving forces being transmitted through said housing, said screen also capable of being placed in a deployed position where it extends out the lower end of said housing to collect ground water, said screen having a ridge formed adjacent its upper end, said ridge engaging said shoulder of said housing when said screen is in its deployed position to prevent further downward movement of said screen;
• and
• an expendable drive point positioned in said housing opening and abutting against said housing lower end during driving of said device into the ground so that the driving forces are transmitted to the drive point solely through said housing, said drive point being disengaged from said opening prior to said screen being deployed.