DEFINITION: Key structure is made up of rotary carried helical blades which goes around as the same direction of water flow. CHARACTERS: 1. Removable structure, Inner slot web, easy maintenance. 2. Dry structure, magnetic drive, keeping clear for long. 3. Low start flow, low pressure loss at big volume flow, (e.g. 100mm water meter: Start flow 0.1CBM per hour, least flow 0.4 CBM per hour, average flow 90CBM per hour). 4. Same install size as rotary type. 5. Remote transmission device can be added upon request. 6. All technical figures are conformed with GB/T778.1~3-1996 which is to equivalent ISO4064 Standard Class B. WORKING CONDITION: . Water temperature≤45ºC(Hot water meter≤90ºC) . Water pressure≤1Mpa MAXIMUM PERMISSIBLE ERROR: . From the minimum flow-rate (qmin) inclusive to the lower zone of the transitionalflow-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%. )