Apparatus for transporting equipment through a conduit

A system for transporting equipment through a fluid-bearing conduit, comprising:

• means for selectively increasing and decreasing the pressure of the fluid within said conduit;
• and,
• pressure responsive propulsion apparatus, said propulsion apparatus including:
• a first element adapted to permit movement of itself in a first axial direction through said conduit and to resist being moved in the opposite axial direction;
• a second element adapted to permit movement of itself in said first axial direction through said conduit and to resist being moved in said opposite axial direction;
• an extendable-retractable element having opposed end portions, said first element being connected to one of said end portions and said second element being connected to the other of said end portions, said extendable-retractable element being adapted to displace its end portions away from one another in response to a decrease in the pressure of the fluid within said conduit and to move its end portions toward one another in response to an increase in the pressure of the fluid within said conduit.

Apparatus adapted to propel itself through a fluid bearing conduit, said apparatus comprising:

• an extensible-retractable element having opposed first and second ends, said extensible-retractable element being adapted to increase the distance intermediate said first and second ends in response to placing the conduit fluid at a first pressure level and to decrease the distance intermediate said first and second ends in response to placing the conduit fluid at a second pressure level;
• a first element adapted to be positioned within said conduit, said first element including a one-way locking device for securing said first element against movement in a first direction through said conduit and permitting said first element to be freely moved in the opposite direction through said conduit, said first element being connected to said extensible-retractable element first end;
• and,
• a second element adapted to be positioned within said conduit, said second element including a one-way locking device for securing said second element against movement in said first direction and permitting said second element to be freely moved in said opposite direction, said second element being connected to said extensible-retractable element second end.