Metering / Delivery / Pumping
When fluids are handled, they are moved, mixed, separated or otherwise processed.
Metering pumps are used to deliver or meter fluids. Valves determine the direction and movement mode of pumped media.
It is often essential that defined volumes per stroke or volumes per period are delivered, independently of the pressure conditions.
In the case of delivery, a precise delivery rate is generally not required, or a sensor determines the switch-off time. In the case of metering, on the other hand, a precise delivery rate is required, and the metering unit can generally be controlled so that exactly this quantity is provided.
One of the special attributes of metering pumps is therefore high metering accuracy.
Examples of metering pumps (or micro-metering pumps) are reciprocating pumps and diaphragm pumps.
Metering pumps are used, among other things, for metering diesel, petrol/gasoline and AdBlue in vehicles, drugs or chemicals in chemical processes, and culture media in biotechnical processes.
The following parameters can be selected or set:
- Metering range
- Pressure-stable characteristic curve
- Medium compatibility
- Gentle delivery of shear-sensitive media
- Solid fractions, abrasive constituents
- Viscosity
- Self-priming
- Delivery in and out of vacuum
- Free from dead space
- Shutting-off
- Dry-run safe
- Decontamination
- Maintenance-friendly
In many cases pumps deliver against very high pressures. On the other hand, aspiration is determined by the ambient pressure. Only the differential pressure between vacuum and ambient pressure can be achieved as final vacuum. This is normally approx. 1 bar.
As a manufacturer of solenoid pumps, Thomas develops and manufactures solutions with metering pumps and delivery pumps.
