Progressive Cavity Pump Repair

A Food Factory having issues with their Progressive Cavity Wobble Pumps

A food factory contacted us having issues with reduced flow in their progressing cavity wobble pumps which had been ran dry. Although producing less flow than required, they were essential to operation of their effluent treatment unit and had to be left in situ until a replacement pump could be supplied and installed.

Wobble pumps operate differently to progressing cavity pumps in that the rotor wobbles within the stator rather than completing a full 360° motion. Wobble pumps are used as they are a simple design with only one joint, are easy to maintain, compact in design as they can be directly driven by the motor without gearbox, to generate high pressures with fluids containing solids, or which are viscous in nature.

Once a new pump was installed, 2 wobble pumps were returned to us at separate intervals for inspection and repair.

Due to the tight clearances within these types of pumps, should the pumps be ran dry the stators are burned, increasing tolerance and inefficiency within the unit, reducing pump efficiency due to recirculation.

These are often a difficult pump to repair with specialist knowledge required in order to repair the units correctly.

Inspection, Sourcing of Spares and Repair of the Pumps

The client was unsure of which parts were required, so we sourced all required spares, keeping them on standby for when the pumps were returned.

The pumps were thoroughly inspected upon return at which point it was noticed the extra fan cooling was not working as expected.

When inverter driven pumps are ran at slow speeds, extra fan cooling is required for low motor speeds as the motor fan speed is too slow to generate enough wind for effective cooling of the motor.

Extra Fan cooling is a separate self-powered fan which operates continuously at full speed, ensuring the motor is fed with the required cooling at whatever rpm the pump is ran at.

The pumps were swiftly repaired and returned to site with the customer having two operational units and one back up which we often recommend for critical plant services.