By Phillip de Villiers, Vesconite Bearings
Metal-on-metal contact can result in galling and unwanted pump vibration, as well as severe damage to the pump; therefore, wear rings have become a critical component in many pump systems to prolong the life-cycle of a pump. Vesconite Bearings’ Hilube polymer wear rings are proving so popular that they are currently the company’s most important wear component for the pump industry—furthermore, they additionally save systems on electricity costs to such a great degree that the components offer a fast return on investment.
HOW HILUBE WORKS
The wear rings are used to restrict the pressure leakage of the fluid between the inlet of the impeller and the pump casing in centrifugal pumps. The wear rings are made from the thermoplastic Vesconite Hilube, which is a low-friction, wear-resistant polymer that replaces traditional metals such as bronze and stainless steel as well as other thermopolymers.
Here are the benefits:
- They replace metal components that require large running clearances to avoid metal-on-metal contact.
- They improve efficiency since tighter running clearances can be applied.
- They do not require pump redesigns, since they can fit into the same housings used by metal wear rings and, because they are press fit, do not require mechanical fitment or glue.
- They can be easily machined from a variety of tube stock or they can be machined for use us-ing Vesconite Bearings’ machining capability.
- They are impervious to salt-water corrosion and thus are ideal for sea water and reverse osmo-sis pumps where galvanic corrosion may destroy stainless steel wear rings.
- They resist cavitation, a problem often encountered with metal wear rings.
- Vesconite Hilube is approved, including by NSF61 and WRAS, for drinking water applications.
ELECTRICITY COST SAVINGS
The installation of Vesconite Hilube polymer wear rings can result in electricity savings that more than pay for the wear ring. This was the result of a study by a large pump original equipment manufacturer (OEM) that compared energy usage on a typical submersible pump when a Vesconite Hilube wear ring was in place and when a bronze wear ring had been installed.
Vesconite Hilube is a low-friction wear-resistant polymer. Wear rings made from the material are designed to seal the pressure leakage of the liquid between the inlet and the impeller and the pump casing, and should result in a higher pumping efficiency due to lower bypass.
The pump OEM’s results independently proved Vesconite Hilube’s ability to improve pumping efficiency and decrease electricity usage. The study showed a 0.11 kilowatts per hour energy reduction when operation of the pump with a large diameter bronze wear ring was compared with operation of the same pump type with a dimensionally-identical Vesconite Hilube wear ring.
Assuming the Vesconite Hilube wear ring’s use on an industrial pump, operating twenty-four hours a day, 365 days a year, the electricity savings from installing a Vesconite Hilube wear ring add up, particularly when the pump is operated in a jurisdiction in which electricity charges are high.
In the specific pump that was studied by the OEM, the wear ring would have a three-month payback even where a low electricity cost was assumed. Electricity savings for a five-to-ten stage submersible pump can be significant if the electricity savings of each stage are added together.
HOPE FOR THE FUTURE
With concerns about global CO2 emissions from electricity generation—which reached 12Gt in 2010—as well as an awareness that pumps account for 10 percent of global electrical energy consumption, technological interventions are valued by pump manufacturers and pump users.
They are also of interest to state and national governments that are interested in reducing carbon emissions to keep global warming under 1.5 degrees Celsius.
FOR MORE INFORMATION
Vesconite Bearings is a world-leading manufacturer of low-friction, low-wear polymer bearing materials for a wide range of industries. Selling to over 100 countries, these include the pump, agriculture, railways, mining, heavy transport, hydro, renewable-energy, earthmoving, marine, and construction industries. For more information, visit www.vesconite.com.
MODERN PUMPING TODAY, June 2020
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