effect of magnet on a flow meter used for drinks and beer

This video shows susceptibility of a magnetic (hall effect) flow meter to external magnetic field. This sort of flow meter is commonly used in water and beverage (drinks) applications.

The flow meter has the water flowing through it at the same flow rate all the time in the video, which is about 25 pulses per second.

To start with, we see the flow meter working correctly.

Part I - first magnet
When the magnet is strong enough it saturates the hall sensor and no pulses are counted at all.

Part II - magnet off to one side
When the magnet isn't strong enough, or is placed away from the hall sensor, it doesn't cause saturation, so some pulses are still counted. However, it seems to induce a lot of noise and so some of the pulses are missed.

Both of these effects would cause the sensor to undermeasure the volume of whatever is being measured, be it beer, lager, water or hot coffee!

Category:

Science & Technology

Tags:

• flow
• meter
• magnet
• coffee
• beer
• water
• lager
• volume
• flowmeter