An IV set (10) includes a drip chamber (24) and a pressure activated valve (50). The drip chamber has an operable liquid height and an outlet orifice (34). The pressure activated valve is disposed proximate the outlet orifice of the drip chamber and includes a sealing orifice (52), a valve, and a biasing mechanism (56). The sealing orifice and the operable liquid height correspond to a head. The biasing mechanism biases the valve against the sealing orifice with a force less than the head of the operable liquid height to control the flow of liquid through the pressure activated valve.
