sealed hollow structure as shown in fig4 and 5 specifically fluid can be fed from the drip chamber 4 the first plastic iv tubing 3 and the inlet 211 into the casing 2 to accumulate therein as such the floating member 11 and the valve member 12 as a unit float in the casing 2 in fig4 it is shown that the recess 115 is filled with fluid and a portion of space of the casing 2 below the flow regulator 1 is filled with fluid level of the fluid in the casing 2 may drop due to fluid flow out of the casing 2 via the inner tubing connector 222 the outer tubing connector 223 and the second plastic iv tubing 5 in a position of fig5 the inner tubing connector 222 is completely blocked by the flat member 122 of the valve member 12 as a result the fluid flow is stopped as shown in fig6 a and 6b specifically in a second configuration the valve member 12 is inverted bowl shaped and comprises an upward tapered hollow member 121 a flat member 122 and a space 123 open to bottom the valve member 12 can be disposed in the chamber 113 through the bottom opening 112 the valve member 12 can be oriented with bottom being open as that shown in fig6 a and 6b prior to disposing.