progressing cavity pump
Gentle dosing of solid-loaden media – even at high pressures and viscosities
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.
Range of applications of a progressing cavity pump
Progressing cavity pumps are primarily used with media that have the following features;
- fluids with or without solid contents (Max. solid size up to 150 mm)
- low to high viscosity (1mPas to 3 millions mPas)
- Thixitropic and dilatant
- shear sensitive
- non-lubricating and lubricating
- aggresive (pH 0 -14)
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
Benefits of a progressing cavity pump
- Flow in proportion to speed
- precise dosing
- continuous, gentle and low-pulsation flow
- large free ball passage (up to 150 mm)
- high suction capacity
- low life-cycle costs due to long lifetime and meantime between failure
- reverse rotation and flow
Delivery characteristics of a progressing cavity pump
Flow rate and pressure are depending on pump size, geometry and stages of the conveying elements and have to be defined depending on medium and application.