Abstract: A clamp (10) including a housing (11) being a first member having a first passage (16) therethrough providing a first jaw and a first opening to said first passage (21) from one side; a shutter (12) being a second member having a second passage therethrough providing a second jaw and a second opening to said second passage (27) from one side; said second member being engaged with said first member far relative sliding movement between an open position in which said first and second jaws are spaced apart and said first and second openings are at least partially aligned and provide access to said first passage from one side and a closed position in which the first and second jaws cooperate to clamp a portion of a bag to be closed there between. The shutter is biased closed by springs (13) and (14) located within the closed passage end of the housing.

Abstract: A clamp (10) including a housing (11) being a first member having a first passage (16) therethrough providing a first jaw and a first opening to said first passage (21) from one side; a shutter (12) being a second member having a second passage therethrough providing a second jaw and a second opening to said second passage (27) from one side; said second member being engaged with said first member far relative sliding movement between an open position in which said first and second jaws are spaced apart and said first and second openings are at least partially aligned and provide access to said first passage from one side and a closed position in which the first and second jaws cooperate to clamp a portion of a bag to be closed there between. The shutter is biased closed by springs (13) and (14) located within the closed passage end of the housing.

Abstract: For extracting a liquid (such as oil) from a porous medium, the liquid is subjected to pulses that propagate through the liquid flowing through the pores of the medium. The pulses cause momentary surges in the velocity of the liquid, which keeps the pores open. The pulses can be generated in the production well, or in a separate excitation well. If the pulses travel with the liquid, the velocity of travel of the liquid through the pores can be increased. The solid matrix is kept stationary, and the pulses move through the liquid. The pulses in the liquid can be generated directly in the liquid, or indirectly in the liquid via a localised area of the solid matrix.