In order to meet process requirements in oil and gas, petrochemical or chemical plants, whenever capacities are below those achievable with a conventional centrifugal pump, Finder Pompe had designed a low flow, high head pump series.
Conventional centrifugal pumps, in fact, could not handle low capacities duties, mainly because of suction recirculation, resulting in increased vibrations that involve axial movement of the shaft, with subsequent possible damage to the bearings and to the mechanical seals and of temperature rise, thus affecting the minimum flow rate. Finder partial emission pumps, the PEP series, fitted with a “Barske” type star impeller, can easily meet the low flow, high head process requirements without the use of increased speed solutions.
The operating range of the PEP series goes from less than one to 32m3/hour, up to 300mt head, with casing pressures 50Bar and over.
The pump is featured by an open impeller with full radial vanes and 90° exit angle, in a concentric volute. The energy is transferred to the liquid in a forced vortex regime and converted into pressure in a diverging diffuser. The peculiarity of the PEP range is that the required output velocity is obtained by increased impeller diameter instead of increased rotating speed. Low rotating speed grants low NPSHr values all over the operating range: in all PEP pumps, NPSHr remains less than 1m @ 3000rpm without the use of inducers, which are often restricting the pump operating region.
Open impeller design and generous clearances allow moderate solid contents in the process fluid and drastically reduces the wearing between the casing and the impeller.
PEP pumps offer several advantages compared to conventional volute pumps and to increased speed pumps.
The main ones are:
Advantages vs conventional volute pumps
- Eliminates impeller backflow, which normally causes erosion, noise, vibrations
- Reduces radial load to prevent shaft deflection and high vibrations
- Provides low and stable NPSHr properties throughout the pump curve
Advantages vs increased speed pumps
- Low and stable NPSHr, no inducer needed
- Less sensitive to off-design conditions
- Maintenance-friendly: no gearbox; simple to disassemble and reassemble; easy to change cartridge mechanical seals
- Lower investment cost
- Lower maintenance costs
Low flow, high head pumps are available in several configurations:
- OH2 – PEP Series
- OH2 – Magnetic Driven – PEPMD
- OH2 – Dual stage – D-PEP Series
- OH3 – L-PEP Series
- BB2 – B-PEP Series
- VS4 – V-PEP
- Special version: BB2 in vertical execution