Figure 1: This LPG pump did not use Vespel® CR-6100
Figure 2: This LPG pump had Vespel® CR-6100 wear rings and kept running.
How to Make LPG Pumps More Reliable
Consider the two photos above. The LPG pump in Figure 1 used metal wear rings and bronze bushings. When it ran dry, the pump seized, the shaft broke, and there was extensive damage throughout the assembly. The LPG pump in Figure 2 used Vespel® CR-6100 wear rings and throttle bushings. When it ran dry, there was essentially no damage. After new seals were installed, the operators were able to put it back into service whereupon it ran at full rate with no loss of efficiency.
- LPG is a very light hydrocarbon, creating a risk of pumps running dry
- Vertical multi-stage LPG pumps often run dry at start up
- Dry running damages carbon or bronze shaft bushings
- Excessive clearance at the wear components causes mechanical seals to fail
- Upgrade stationary wear rings and bushings to Vespel® CR-6100
- Reduce the wear ring clearance
- Keep the shaft bushing clearance at the original design value
- Ensure good rotor concentricity through good pump repair practices
- Lower risk of seizure
- Longer life from the shaft bushings
- Lower vibration
- Fewer mechanical seal failures