LIQUID GASKETS AND ADHESIVES PROTECT PUMPS
03 December 2021
LIQUID GASKETS and adhesives reduce pump maintenance, and can be part of a proactive maintenance strategy, says Henkel.
In today’s fast-moving, constantly evolving industrial landscape, pump downtime can be extremely costly in lost output, particularly where the pump has a production-critical role. For this reason, those operating in processing sectors such as paper, power generation, chemicals, sugar, mining and oil and gas, will know all about the pressures that come with pump maintenance. Adopting a proactive maintenance strategy is key to eliminating common failures modes and extending the useful life of pumps, which is why increasing numbers are turning to liquid flange gaskets and thread locking adhesives.
Conventional pre-cut compression gaskets are prone to long-standing issues like shrinkage, relaxation, extrusion and breakage, all of which can promote leaks between the bearing frame and adapter, or between the stuffing box and pump casing, for example. The optimum way forward is to completely eradicate the requirement for a cut gasket by switching it with a liquid gasketing adhesive. Such a product fills all the air space between the mating parts to create a perfect seal, while simultaneously eliminating flange face corrosion.
Among those able to benefit are MRO workshops, where any liquid gasketing product needs to be fast and reliable, yet easy to dismantle for further maintenance activities. In addition, the product must allow easy application and offer lower costs than traditional gaskets and slow-curing chemical solutions.
Among the increasingly popular solutions for this application is Loctite 518 a methacrylate-based gasketing product that is ideal where low strength is of paramount importance. For many MRO workshops this product is delivering a 50% time saving thanks to fast cure times, reducing the time required before reaching the test bench. In addition, as a single-component adhesive, the product is easy to apply using either a gun or a brush, while low cost and easy removal are further advantages. The adhesive is suitable for use on all types of pumps, including centrifugal, submersible, diaphragm, disc and double-jacket.
A typical process would involve the use of Loctite SF 7063 general purpose parts cleaner, before applying Loctite 518 for flange sealing. To remove the cured product, simply spray the surface with Loctite cleaner.
Among those testifying to the benefits is a manufacturer of cast iron gearboxes and geared motors. While the company was already using liquid gasketing on an adapter assembly flange, the resulting poor seal was causing a 5% leakage rate, along with testing and production delays due to the adhesive’s slow cure rate.
After trialling alternative brands, the manufacturer found that a Loctite gasket sealant met all of its performance criteria. The product effectively fills the gaps between the flange surfaces and cures quickly so that close-fitting parts can be instantly pressure tested to 276 kPa (40 psi). Leaks are now a thing of the past and disassembly is far easier.
Another common issue with pumps is shaft misalignment. When shafts on rotating equipment are misaligned, the potential for costly, unplanned machine downtime rises dramatically. Typical among the outcomes is premature bearing failure.
A simple and cost-effective way to ensure and maintain critical shaft alignment is to fill the airspace with a suitable liquid adhesive. This strategy has the effect of resisting vibration, shock, thermal expansion and contraction by unifying the assemblies. Such an approach maintains the clamp load and keeps bolts from loosening, which in turn ensures ongoing shaft alignment. Ultimately, pump users can extend mean time between failures (MTBF) and enjoy full bearing life expectancy.
Growing numbers are turning to Loctite 290 medium-strength thread locking adhesive for this critical task. A case in point is an industrial maintenance/engineering services facility that had issues with shaft alignment for an electric motor and centrifugal pump that supplies water to the boiler of a commercial building. Previously, the loosening of mounting bolts was leading to shaft misalignment and failures.
To overcome the issue, the maintenance specialist opted for a new process. The company began cleaning the nuts and bolts using Loctite SF 7603, before aligning the shaft with a laser and applying Loctite 290 to the threads prior to fastening at the proper torque. This solution is proving successful in maintaining alignment until the next scheduled maintenance (every 3 years).
Maximise machine uptime
Proven adhesive and sealant products are available to help with a myriad of further pump maintenance tasks. Retaining compounds, for instance, prevent bearings from fretting or spinning either on their shafts or within their housings. As another example, numerous products exist to help prevent corrosion or chemical attack.
In short, pump maintenance is time-consuming, inconvenient and costly, so why not take steps to minimise requirements and bring reliability to pump operations.
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