Clamp (210) for compressing a flexible tube (12), comprising: a first member (214, 216) having a first end and a second end； a second member (216, 214) with a first end and a second end, the first and second members moveably coupled at their first ends to move into and out of a clamping position to apply a compressive force to the tube (12)； a locking member pivotally coupled to the second end of at least one of the first member and second member, the locking member adapted to hold the first and second members in the clamping position； and a lever member (234) moveably coupled to one of the first member and the second member to apply an additional compressive force to the tube.
