Is there a Doctor in the Plant Room?

At the customer’s beverage production site, in-house engineers identified a problem with a seal on a rotary lobe pump. The pump – used for unloading and transferring glucose from tankers to bulk holding tanks – was leaking substantial quantities of oil and glucose onto the plant-room floor. 

The engineers traced the leak back to the rear of the pump and its double mechanical seal. However, ERIKS’ engineer took a step back from the obvious. 

Symptom or cause?

The pump with a failed seal can be compared with to a patient with a sore foot. 

The sore foot is the obvious symptom, and a painkiller would relieve it, but why is it sore? An experienced doctor would take a broader view, which could reveal that the foot is sore because the patient is limping, and the limp signifies a hip replacement is required. In the same way, stopping the leak by replacing the seal won’t deal with why the seal is failing in the first place. 

So, taking a more holistic view, the ERIKS engineer made three observations:

1) Double mechanical seals require a pressurised barrier fluid, but there were no pressure gauges installed.

2) The discharge pipework of the system was unsupported.

3) The motor gearbox alignment was imperfect, and – when equipment was reinstalled after removal for any reason – alignment was by eye only.

The ERIKS prescription

Although none of these factors is the sole cause of the seal’s failure, they are all contributing in different ways to the pump’s reliability issues. 

Firstly, with no pressure gauge fitted, there’s no way of knowing if the barrier fluid is at the required pressure. If it isn’t, the seal will be ineffective.  

Secondly, unsupported pipework places undue load on the pump, which can affect its overall reliability and have a knock-on effect on the seal. 

Thirdly, aligning the motor gearbox unit by eye leads to misalignment, premature coupling failure, and reduced motor gearbox and driven-plant life. 

ERIKS’ engineer recommended installing pressure gauges and pipe supports; following realignment best practice for every unit installation; and checking alignment at least annually. 

Doctors use their know-how to make people better. ERIKS use theirs to make industry work better.