Progressing cavity pumps belong to the group of rotating positive displacement pumps. They are self-priming, valve-less, and due to their high process liability and suction capacity they are often used for the continuous, gentle conveyance and precise dosing – in proportion to speed – of difficult media.
Functioning of a progressing cavity pump
The delivery principle is based on a rotor which turns in an oscillating motion within a fixed stator. The coordinated, spiral geometry of both components creates delivery chambers in which the medium is transported from the suction to the pressure side. Due to the design of rotor and stator, hardly any pulsation or shearing forces are effecting the fluid. Instead, the medium is transported gently and continuously.
Consistency and especially the viscosity are not a factor for the delivered flow with this displacement technology; the transported quantity is determined by the speed alone and – in combination with a frequency inverter – can be regulated conveniently and with precision. This enables an accuracy of between five and three percent to be achieved; small dis-pensers even achieve one percent.
Hopper pumps are available with screw conveyors and bridge breakeing devices for media with high dry material content.
Technical features of a progressing cavity pump
- High suction capacity up tp 9 mWC
- Direction of rotation and flow can be reversed
- Installation in any orientation possible
- quiet smooth running
- low pulsation
- temperatures from -20°C to +200°C