Liquid micro-flow meter

The utility model provides a device for accurately measuring flow quantity of liquid so that water is prevented from being stolen in a slow water dropping way and water supply departments conveniently monitor water use. A liquid micro-flow meter comprises a meter casing provided with a water inlet and a water outlet, wherein a rotating mechanism composed of an impeller and a spline shaft, and a metering mechanism formed by the combination of gears driven by the spline shaft are arranged in the casing. The utility model is characterized in that a piston which upward and downwards slide along the spline shaft is arranged in the meter casing; a water inlet hole and a water outlet hole are arranged on the piston from top to bottom; a micro rotor is arranged in a cavity of the piston coaxially to the spline shaft. The utility model is conveniently arranged on a water supply pipeline. When the water flow quantity is normal, water flow pushes the piston to upward slide to open the water inlet of the meter, and the impeller of the meter rotates to drive an indicating dial of the meter to work. When the flow quantity is reduced, the piston downwards slide to close the water outlet of the meter, micro water enters the cavity of the piston through the water inlet hole on the piston so as to push the micro rotor in the piston to rotate, and similarly the indicating dial of the meter is driven to work.