Apparatus (10, 100) comprising a valve having: a valve body (12, 112) configured with an upstream port (12a, 112a) to allow upstream pressure to be measured and a downstream port (12b, 112b) to allow downstream pressure to be measured; and a valve ball (14, 114) configured in the valve body so as to be operable between open and closed positions to allow for fluid flow and no fluid flow, respectively, and also configured with a calibrated member configured to form a calibrated orifice (14a, 114a) to allow the fluid flow, the calibrated member having a flow coefficient, an upstream pressure tap (14b, 114b) located upstream of the calibrated orifice (14a, 114a) and in fluidic communication with the upstream port (12a, 112a) in order to measure upstream pressure of the fluid flow when the valve ball (14, 114) is in the open position, and a downstream pressure tap (14c, 114c) located downstream of the calibrated orifice and in fluidic communication with the downstream port (12b, 112b) in order to measure downstream pressure of the fluid flow when the valve ball (14, 114) is in the open position, so that a direct measurement of the fluid flow may be determined based at least partly on signaling containing information about a measured pressure differential between upstream and downstream pressure taps (14b, 14c; 114b, 114c) in relation to the flow coefficient of the calibrated orifice (14a, 114a) when the valve ball (14, 114) is substantially in the open position, the apparatus characterized by the upstream port and the downstream port being configured on a common axis, on which the valve ball (14, 114) is configured to rotate. a valve body (12, 112) configured with an upstream port (12a, 112a) to allow upstream pressure to be measured and a downstream port (12b, 112b) to allow downstream pressure to be measured; and a valve ball (14, 114) configured in the valve body so as to be operable between open and closed positions to allow for fluid flow and no fluid flow, respectively, and also configured with a calibrated member configured to form a calibrated orifice (14a, 114a) to allow the fluid flow, the calibrated member having a flow coefficient, an upstream pressure tap (14b, 114b) located upstream of the calibrated orifice (14a, 114a) and in fluidic communication with the upstream port (12a, 112a) in order to measure upstream pressure of the fluid flow when the valve ball (14, 114) is in the open position, and a downstream pressure tap (14c, 114c) located downstream of the calibrated orifice and in fluidic communication with the downstream port (12b, 112b) in order to measure downstream pressure of the fluid flow when the valve ball (14, 114) is in the open position, so that a direct measurement of the fluid flow may be determined based at least partly on signaling containing information about a measured pressure differential between upstream and downstream pressure taps (14b, 14c; 114b, 114c) in relation to the flow coefficient of the calibrated orifice (14a, 114a) when the valve ball (14, 114) is substantially in the open position, the apparatus characterized by the upstream port and the downstream port being configured on a common axis, on which the valve ball (14, 114) is configured to rotate.