DEFINITION: Set of moving device that fitted into a closed conduit driven directly by water flow. Its turbine rotor rotates about the axis which is perpendicular to water flow. WORKING PRINCIPLES: Water flow drives vane rotate. Rotating times which is proportional to water flow speed are gathered, hence total volume passed through water meter is recorded. CHARACTERS: 1. Types: Wet. 2. Wide measuring range, high accuracy. 3. Stable measuring capacity. 4. Long working life. 5. Low pressure loss. 6. All technical figures are conformed with GB/T778.1~3-1996 which is equivalent to IS04064 Standard Class B. WORKING CONDITION: . Water temperature≤45º C(Hot water meter≤90º C) . Water pressure≤1Mpa MAXIMUM PERMISSIBLE ERROR: . From the minimum flow-rate (qmin) inclusive to the lower zone of the transitional flow-rate (qt) exclusive: ± 5%. . From the transitional flow-rate (qt) inclusive to the higher zone of the maximum flow-rate (qmax) exclusive: ± 2%(hot water meter± 3%. )