When deciding on the type of seal system for a centrifugal pump, operators must choose according to their unique application. Failure to select the proper mechanical seal type can lead to loss of pump integrity, breakdowns and costly repairs. To avoid these undesirable results, all operators must consider the following factors before deciding.
Type of Fluid to be Pumped
The fluid that you’re pumping is the single most important factor to consider when deciding on a seal type.
Factors such as cleanliness, lubricity and volatility will significantly affect the mechanical seal and seal support system design.
Pump Fluid Pressure
The amount of pressure exerted at a mechanical seal’s faces has a significant effect on its performance. If a pump is to be operated at low pressures, an unbalanced mechanical seal will be suitable. However, in conditions where higher pressures are anticipated, balanced seals will prove a more reliable solution.
Temperature Considerations
Balanced mechanical seals perform better than their unbalanced counterparts in conditions where the operating temperatures are higher than normal. Heat sensitive components are better preserved in balanced mechanical seals compared to other seal types.
Operator Safety Concerns
As it goes for all types of machinery, operator safety is the top priority. The use of double mechanical seals in centrifugal pumps provides additional protection as they have increased sealing capacity and are generally more reliable.
Lifetime Cost Vs. Initial Cost
It is important to think about the mechanical seal in terms of its total lifetime costs – not so much by its initial cost. Start a reliability program that defines the cost of failure and justify it by increasing the mechanical seal’s mean time between failures.
Look to your mechanical seal supplier for help with seal selection, best operating practices, and seal flush plan recommendations.
If you have specific questions, ask us! We gladly provide mechanical seal technical assistance to pump repairers and end-users Australia wide.