It’s always important to make sure your magnetically driven centrifugal pumps run smoothly and efficiently. However, one common issue that can lead to catastrophic pump failure is dry running. When pumps are operated without sufficient lubrication, the resulting friction generates excessive heat, damaging critical components such as the bearings. One of the solutions that we have found works well is Runsafe SIC – aDLC coating which increases efficiency and extends the lifespan of your pumps.

The Problem

Dry running occurs when a pump operates without an adequate supply of fluid or lubricant. This can happen due to accidental start-up without priming, loss of suction, or simply just insufficient lubrication. When a mag drive pump has been run dry, the high friction coefficient creates quite a lot of heat. This increase in temperature can cause the surfaces to degrade, leading to pump failure. This is a critical issue that needs to be addressed to ensure the reliability and longevity of the pump.

The Solution

To combat the challenges posed by dry running, an innovative solution was created – the aDLC coating. The aDLC (amorphous diamond-like carbon) coating is a thin layer, just a few microns thick, that can be applied to the silicon carbide bearings using a special process called “plasma-assisted chemical vapour deposition.” This coating revolutionises pump performance by enhancing key properties such as hardness, wear resistance, thermal conductivity, and chemical resistance.

The Properties of aDLC Coatings

     Amorphous and isotropic structure

     Excellent hardness (HV 0.05 4000-6000)

     Good elasticity despite high hardness

     High wear resistance

     Optimum surface qualities

     Good thermal conductivity

     Temperature-resistant up to 300°C

     Universally resistant to chemicals

     Low coefficient of friction without lubrication (0.02-0.04)

Engineering Benefits of aDLC Coatings

Upgrading to Runsafe SiC bearings with aDLC coatings contributes to the overall efficiency and reliability of magnetically driven pumps.   The reduced friction coefficient significantly improves pump efficiency. With minimal friction, the pump requires less power to operate, resulting in energy savings and reduced operating costs and a range of benefits including:

• Higher Efficiency and Lower Power Consumption
• Higher efficiency
• Lower power consumption
• Reduced friction and assisted lubrication
• Coating thickness will not affect the final dimensions
• Ultraclean surface

The Proof is in the Pudding

When centrifugal pumps have been run dry, failure can occur within seconds.  We tested the effectiveness of Runsafe SiC using the UTS-B 80-50-200, one with a Hastelloy C isolation shell and on with an isolation shell manufactured in Zirconium Oxide.  The testing conditions and results are as follows:

Pump Model: UTS-B 80-50-200

Materials: Stainless Steel

Bushes: Runsafe SIC

Test Steps:

Pump start-up for tank unloading

Empty tank – operate the pump until failure

Dry Running Test with Hastelloy C Isolation Shell

Result: Pump failure occurred after 46 minutes and 30 seconds of dry running.

Dry Running Test with Zirconium Oxide Isolation Shell

Result: Pump failure occurred after 53 minutes and 40 seconds of dry running.

The use of a zirconium oxide isolation shell in the second test significantly reduced the temperature inside the pump, preventing complete vaporization of the remaining fluid. This allowed for lubrication of the bushes, resulting in an extended running time under critical conditions. Additionally, the absence of eddy current losses in the zirconium oxide isolation shell may lead to energy savings.

How Important Is Protection against Dry Running

Dry run protection is like insurance – you don’t appreciate how important it is until your pumps have been run dry.  The simple but innovative solution provided by aDLC coatings not only protects against dry running but also improves efficiency, reduces power consumption, and extends the lifespan of your pump… and the testing proves it.

Embrace the power of dry run protection, and experience the impact of Runsafe SiC.  For more information on aDLC coatings call us on 01933 674777 or email sales@www.cdrpumps.co.uk