a flow meter for measuring the volume of fluid flowing through the meter includes an inner cylindrical tube through which the fluid flows and an outer cylindrical tube tending over the inner cylindrical tube . the outer cylindrical tube is radially spaced from the cylindrical inner tube to provide an annular cylindrical space between the inner cylindrical tube and the outer cylindrical tube . a seal between the inner cylindrical tube and the outer cylindrical tube closes the annular cylindrical space adjacent ends of the annular cylindrical space . the inner cylindrical tube further defines at least one opening in a wall of the inner cylindrical tube to balance the fluid pressure in the annular cylindrical space with the pressure in the inner cylindrical tube . a torus wedge flow restriction member is integrally formed within full internal circumference the inner cylindrical tube for restricting the flow of fluid through the inner cylindrical tube and produces a pressure drop in the fluid as it flows past the flow restriction member . the inner cylindrical tube and the outer cylindrical tube in combination further define at least one port for receiving a pressure sensing device to measure the pressure of the fluid flowing through the flow meter .