Modified Gear Pumps Offer Important Advantages
The characteristics of gear pumps makes them particularly suitable for metering and transferring 'difficult' liquids, such as those which are viscous or thin.
As well as positive displacement pulseless smooth flow operation, the other benefits offered by gear pumps include; they are self-priming, offer lower NPSHR, have fewer wearing parts, are capable of flow accuracies as low as 0.5% and are easy to repair.
A good example are Liquiflo magnetically coupled gear pumps, available through MICHAEL SMITH ENGINEERS. The 33 Series pump featured has been successfully pumping solvent based products with a range of viscosities ranging from 0.2 to 10 cps. This model incorporates a patented Dual-Kan (double wall containment can) and clamp-on design temperature control jacket, making it ideal for liquids transfer applications which require precise and uniform temperature control.
Precise temperature control is commonly required when pumping liquids which solidify or become viscous when temperature decreases. Either steam or a hot liquid can be used to circulate through the jackets and the Dual-Kan to ensure that the entire pump operates at an even temperature.
The base material for this pump is Hastelloy C276 and because of the low lubricity of the fluids being handled features a combination of Silicone Carbide bearings and Tungsten Carbide coated shafts to provide optimum life. The pump is driven by a close-coupled 0.55 kW ATEX ExD IIC T4 motor fitted with an integral frequency inverter unit, the main benefit of this being that the unit was self-contained on the customers skid.
This Liquiflo 33 Series pump is just one of a range of Liquiflo RotoGear 3 and H Series covering flow rates from 1.9 lit/min up to 220 lit/min at pressures up to 15 bar.
Source: Michael Smith Engineers