What distinguishes a flow switch from a flow meter?

• A. A flow switch quantifies flow; a flow meter opens circuits
• B. A flow switch operates continuously; a flow meter does not
• C. A flow switch acts on flow presence; a flow meter quantifies flow
• D. A flow switch is more expensive than a flow meter

Answer: (C)

A flow switch is designed to detect the presence or absence of flow within a system and usually activates an output signal or an alarm when a specific flow condition is met or not met. Its primary function is to monitor flow conditions and ensure that the process operates safely and effectively. It does not measure the actual flow rate or quantity of fluid passing through the system but rather serves as a binary device—indicating whether flow is happening.

On the other hand, a flow meter quantitatively measures the flow rate of fluid in a system. It provides precise readings of the volume or mass flow of the liquid, which can be continuous and displayed in various units like gallons per minute or liters per second. Flow meters are essential for applications where knowing the flow rate is crucial for process control, budgeting resources, or maintaining efficiency.

The distinction lies in their primary functions: while a flow switch indicates the presence of flow, a flow meter quantifies how much fluid is flowing.