An apparatus for measuring flow of a process fluid, comprising: an elongate spool providing a spool conduit (140; 256) therethrough adapted to be coupled in line with process piping to receive the flow of process fluid; a meter body (112; 250) carried by the elongate spool receiving the spool conduit (140; 256) therethrough, the meter body (112; 250) including a flow measurement component opening (144; 252) which extends from the spool conduit (140; 256) to outside of the meter body (112; 250); a plurality of standardized flow measurement components (170A-D; 270, 290, 300, 304, 320, 330) configured for placement in the flow measurement component opening (144; 252) of the meter body (112; 250), wherein each of the plurality of standardized flow measurement components (170A-D; 280, 290, 300, 304, 320, 330) has an associated carrier (114; 150; 272) configured to removably mount to the meter body (112; 250) and couple the associated one of the plurality of standardized flow measurement components (170A-D; 280, 290, 300, 304, 320, 330) to the spool conduit (140; 256) through the flow measurement component opening (144; 252); and a flow measurement transmitter (116; 274) coupled to the flow measurement component (170A-D; 280, 290, 300, 304, 320, 330) configured to measure the flow of process fluid based upon an interaction between the process fluid and the flow measurement component (170A-D; 280, 290, 300, 304, 320, 330); wherein the plurality of standardized flow measurement components (170A-D; 280, 290, 300, 304, 320, 330) comprises either: orifice plates (170A, 170B) and averaging pitot tubes (170C, 170D); or a magnetic flow tube, a vortex shedding bar, a coriolis meter, ultrasonic transducers, a thermal mass sensor, a wedge, and a venturi tube. an elongate spool providing a spool conduit (140; 256) therethrough adapted to be coupled in line with process piping to receive the flow of process fluid; a meter body (112; 250) carried by the elongate spool receiving the spool conduit (140; 256) therethrough, the meter body (112; 250) including a flow measurement component opening (144; 252) which extends from the spool conduit (140; 256) to outside of the meter body (112; 250); a plurality of standardized flow measurement components (170A-D; 270, 290, 300, 304, 320, 330) configured for placement in the flow measurement component opening (144; 252) of the meter body (112; 250), wherein each of the plurality of standardized flow measurement components (170A-D; 280, 290, 300, 304, 320, 330) has an associated carrier (114; 150; 272) configured to removably mount to the meter body (112; 250) and couple the associated one of the plurality of standardized flow measurement components (170A-D; 280, 290, 300, 304, 320, 330) to the spool conduit (140; 256) through the flow measurement component opening (144; 252); and a flow measurement transmitter (116; 274) coupled to the flow measurement component (170A-D; 280, 290, 300, 304, 320, 330) configured to measure the flow of process fluid based upon an interaction between the process fluid and the flow measurement component (170A-D; 280, 290, 300, 304, 320, 330); wherein the plurality of standardized flow measurement components (170A-D; 280, 290, 300, 304, 320, 330) comprises either: orifice plates (170A, 170B) and averaging pitot tubes (170C, 170D); or a magnetic flow tube, a vortex shedding bar, a coriolis meter, ultrasonic transducers, a thermal mass sensor, a wedge, and a venturi tube. orifice plates (170A, 170B) and averaging pitot tubes (170C, 170D); or a magnetic flow tube, a vortex shedding bar, a coriolis meter, ultrasonic transducers, a thermal mass sensor, a wedge, and a venturi tube.