Mechanical gears and rotating cables have also been historically used to link a turbine flowmeter’s
turbine wheel to indicators. These designs suffer from greater friction than electronic (“pickup coil”)
designs, potentially resulting in more measurement error (less flow indicated than there actually is,
because the turbine wheel is slowed by friction). One advantage of mechanical turbine flowmeters,
though, is the ability to maintain a running total of gas usage by turning a simple odometer-style
totalizer. This design is often used when the purpose of the flowmeter is to track total fuel gas
consumption (e.g. natural gas used by a commercial or industrial facility) for billing.