Which device can be installed in a pipe to measure flow while keeping full flow in the pipe?

Which device can be installed in a pipe to measure flow while keeping full flow in the pipe?

• A. Venturi meter
• B. Orifice plate
• C. Ultrasonic flow meter
• D. Turbine meter

Answer: (A)

A venturi meter is designed to measure flow while preserving full bore flow in the pipe. It achieves this with a smoothly tapered inlet that narrows to a throat, causing the fluid to accelerate and the pressure to drop slightly. Because the contraction is gradual and the walls are smooth, the energy losses are relatively small, so most of the flow continues through the pipe with minimal disruption. By measuring the pressure difference between the upstream section and the throat and applying the Bernoulli/continuity relationship, you can determine the flow rate accurately without creating a large obstruction. Orifice plates also measure flow via differential pressure but introduce a sharper restriction and greater energy loss, so they disturb the flow more. Turbine meters have moving parts and can be more sensitive to debris and require straight-flow conditions. Ultrasonic meters can measure flow with little obstruction, but the venturi’s combination of inline installation and low pressure loss makes it the best fit for measuring flow while maintaining full pipe flow.

A venturi meter is designed to measure flow while preserving full bore flow in the pipe. It achieves this with a smoothly tapered inlet that narrows to a throat, causing the fluid to accelerate and the pressure to drop slightly. Because the contraction is gradual and the walls are smooth, the energy losses are relatively small, so most of the flow continues through the pipe with minimal disruption. By measuring the pressure difference between the upstream section and the throat and applying the Bernoulli/continuity relationship, you can determine the flow rate accurately without creating a large obstruction.

Orifice plates also measure flow via differential pressure but introduce a sharper restriction and greater energy loss, so they disturb the flow more. Turbine meters have moving parts and can be more sensitive to debris and require straight-flow conditions. Ultrasonic meters can measure flow with little obstruction, but the venturi’s combination of inline installation and low pressure loss makes it the best fit for measuring flow while maintaining full pipe flow.