A clamp for clamping flexible tubing is disclosed. The clamp includes a a first element having a first surface with a first corner and a second element having a second surface with a second corner. A flexible element is coupled to the first and second elements, the flexible element is configured such that: when the clamp is not actuated, the first and second surfaces are disposed at an angle to each other； when the first element is displaced toward the second element with the flexible tubing between the first and second elements, the first and second corners cooperate to sealingly compress a first length of the flexible tubing； and as the first element is further displaced toward the second element, the first element rotates with respect to the second element such that the first and second surfaces cooperate to sealingly compress a second length of the flexible tubing.
