Application Notes
Refi nery Applications
Plenty Mirrlees Pumps have been manufacturing RotaryPositive Displacement Pumps for Refi nery services for more than 50 years. Some of the Process Applications and Products that can be handled with Plenty pumps are detailed in this newsletter. Plenty Mirrlees Pumps manufacture three styles of Rotary Positive displacement pumps, that are often utilised on Refi neries.
Twin Screw Pumps are primarily designed for bulk liquid transfer and processing applications involving low viscosity products. The principle design feature is that no metallic contact takes place between the screws or between the screws and their
bores, which enables the pumps to handle a wide range of fl uids, including those with no
lubricating properties. The TWINRO range of two screw pumps is characterised by their smooth, quiet and pulse free operation.The
pumping element consists of two shafts, a driving and a driven shaft, each having a right and left hand screw form. The drive is transmitted through timing gears, which ensure a clearance is constantly maintained between the screws. The shafts are carried in ball and
roller bearings to maintain axial location and the correct clearance between screws and screw bores.As the screws rotate, fl uid is drawn through the suction branch, and fl ows axially from each screw end to the Centre, where it is discharged through the outlet branch. This arrangement results in the
Mechanical seals being subjected to inlet pressure conditions only, resulting in a vastly improved
industrial seal life, whilst the screws are maintained in complete hydraulic balance, eliminating thrust loads on the bearings.
A signifi cant feature of TWINRO pumps is their self priming high lift capability, enabling them to displace large volumes of air and gas from long suction lines.
2000 Series Pumps
Although a Rotary Blade Pump does not readily spring to mind when talking about Refi nery Applications, the Plenty range of pumps are unique.Unlike conventional gear or
vane pumps, the Plenty 2000 Series Pump works on a different patented principle. The addition of a rotating ring (Rotor) to the pumping element, enables the Plenty design to utilise a much stronger internal design. This Heavy Duty design gives a very adaptable pump that can be used for many different refi nery applications on a diverse range of liquids. The standard factory pump is suitable for handling viscosities up to 75,000 cSt.
Three Screw Pumps
Three Screw Pumps are generally utilised on Refi neries for applications such as Forced Lubrication in Lube Oil Systems associated with other on site rotating machines such as Gearboxes, Engines and Turbines etc. and Seal Oil Circulation on
Compressor systems.The TRIRO Three Screw Pump has only three moving parts - a power rotor and two idler rotors. Three Screw pumps are designed principally to pump clean lubricating liquids, and are suitable for operation at high pressure. The three rotors are accurately machi-ned and intermeshed to give a smooth pulse free fl ow and exceptionally quiet pump operation.
2000 Series Pumps - Variable Capacity
The patented Plenty 2000 Series Pump also has the unique capability to deliver an infi nitely variable fl ow rate from full capacity all the way down to zero, and without any form of spillback. These pumps can be supplied with devices to
enable the pump fl ow rate to be varied either by Remote Control, Manual Adjustment or even to match process conditions Automatically using our patented CPC (Constant
Pressure control) mechanism.