Metering pump
Metering pumps (also dispenser) are positive displacement pumps and supply independent of the pressure conditions at the inlet and outlet of the metering pump defined volumes per revolution, stroke or time.
When dosing eg reciprocating pumps, peristaltic pumps, diaphragm pumps, gear pumps or other positive displacement pumps are used (see also pumps).
Special in recent years are very common metering pumps are based on the principle of progressive cavity pumps (Endless piston principle ) is used. These achieve very high accuracy and can also be controlled without additional measuring devices into the metering rate. An additional advantage is that the drive motor of the Winklegradänderungen easily changeable dosing can be adjusted.
Dosing pumps are used (eg as an injection pump ) and Others for adhesive application, the dosage of drugs ( infusions) or chemicals in chemical processes, culture media in biotechnological processes as well as in motor vehicles.
Dosing in the laboratory and industry
For chemistry, biotechnology, food and the environment a variety of dosing pumps are used both in the laboratory and in industry. The feed rate can be adjusted both manually and frequently over a data interface.
When selecting a suitable metering pump following parameters are necessary, consider:
- Dosing
- Pressure-resistant characteristic
- Bidirectional promotion
- Media compatibility
- Gentle pumping of shear-sensitive media
- Solids, abrasive constituents
- Viscosity
- Self-priming
- Support in and out of the vacuum
- Dead space
- Shut-off
- Safe to run dry
- Autoclavable
- Decontamination
- Easy to maintain
- Data interface
Dosing in motor vehicles
In fuel injection metering pumps are used, usually gasoline or diesel oil, with the pressure necessary to deliver the fuel in the combustion chamber or intake tract. One example is the injection pumps of diesel engines.
Furthermore, dosing pumps are used in motor vehicles, the fuel to mix additives, provided that this does not already happen during refueling, as well as for fuel metering for external heaters ( Zusatz-/Standheizungen ).