Tips to Help Prevent Pump Stator Failure

February 14, 2018

Progressive cavity pumps are remarkable devices. The elongated pumps split fluid loads into discrete packages. They accomplish this feat without mixing the fluid, so they're employed in many fluid-based beverage and food applications. Built to handle messy effluent streams, this screw-like rotor can pump abrasive solids. However, this remarkable mechanism relies on an elastomeric stator, a pumping sleeve that's susceptible to damage. Here's how we prevent that stator damage.

Be Aware of Rotor Sizing Issues

As mentioned in the past, the stator can't move away from the rotor. If there's any thermal expansion, the elastomer will expand until it interferes with the rotor. In order to prevent this unfortunate scenario, the cross-sectional area of the rotor needs to be undersized or oversized to accommodate any thermal variances.

Author a Stator Maintenance Guide

Split the different sections into key inspection groups within the preventative maintenance log book. For example, the rotor checks require a micrometre test to align this key rotating metal component. Gear joints and metal scoring problems come next. Abrasive wear patterns look quite unique on the chrome or nickel plated screw. As for a pump stator failure, elastomeric expansion, chemical attack, and rough textural issues illustrate an entirely different set of processing problems.

Note the Exceptional Defects

A cracked stator surface indicates a caustic chemical attack. Not only should this problem be noted and underscored, a responsible party should be immediately informed of this catastrophic event. Left unchecked, such defects will result in an expensive breakdown, a situation that will inevitably require downtime and/or an expensive refit. Smaller wear issues are typically logged so that they illustrate a parts-fatigue trend.

Employ All Investigative Senses

The orange peel structure of the failing pump stator is concealed in the progressive pump housing. Fluid packet transport is failing and there's a subsequent uptick in mixing, something that's obviously undesirable in a food production setting. Is there a smell of burning rubber? A dry run event, perhaps caused by a system clog, will cause friction, even if the interference fit is properly calibrated. Stop the pump and investigate further. Touched gingerly, the stator material is now soft and tacky. Again, thermal energy has corrupted the elastomer.

In a systematically run setting, micrometres and log books rule stator safeguarding measures. They function well while recording potential fatigue trends. However, in the real world, it's core skills that make the difference. A clog, a smell of burning rubber or the feel of massive amounts of thrown off heat, these are the stator failure clues that come to the rescue when a pumping operation is on the line.

Contact Alpha Pumps:

Phone:    (03) 9311 7188
Fax:          (03) 9364 9554
Mobile:    0403 030 830

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