As is customary with orifice plates mounted in vertical pipes, the direction of flow is upward
(from bottom to top), making the bottom tap the “high pressure” side and the top tap the “low
pressure” side. Since this is a liquid application, the transmitter is located below16 the taps in order
to avoid collecting bubbles of air or other gases in the impulse lines.
This particular orifice and flow transmitter (Rosemount model 1151) is used on a process “trainer”
unit at Brazosport College in Lake Jackson, Texas. The transparent flanges, pipes, and process
vessels make it easier for students to visualize the fluid motion.