Challenge

A multinational manufacturer of high voltage IHP motors of 150 to 3000 HP rating in India used an RTV silicone sealant to seal the end shield of the motors. However, the seal created by this sealant failed to perform consistently and failed to withstand IP 65* tests. During a plant survey, Henkel Application Engineer analyzed that the operator takes nearly 15 min to dispense the silicone on the flange area, by which time the silicone would have started to skin over - leading to insufficient bonding on the mating flanges and improper sealing.

*IP 65: There are different degrees of protection of enclosures according to DIN 40050. IP 65 requires the commonly followed for electrical panels and machines to be protected against accidental or inadvertent contact and against ingress of foreign bodies; protected against ingress of dust and protected against water (out of a nozzle) from all directions.

Solution

Loctite 518 Gasket Eliminator an anaerobic Flange sealant was recommended for this application.

Loctite anaerobic gasketing compounds are applied as a liquid sealant to one of the flange surfaces before the parts are assembled. After assembly, they spread and cure between the flanges, filling gaps, scratches, and surface irregularities to provide a durable seal. Because the curing mechanism starts only once parts are assembled, the product does not pose problem of skinning and has consistent bonding and sealing performance.

Loctite gasketing compounds can be dispensed in desired shape and sizes and reduce the need of keeping high inventories. The dispensing operation can be automatic to further reduce application costs and improve process efficiency. They typically cost much lower compared to conventionally used pre-formed gaskets.

Loctite 518 forms a flexible, solvent-resistant seal that will not tear or decay. It seals to 150 °C and fills gaps to 0.050“ (> 1mm). It can be used on flexible metal assemblies, including aluminum surfaces and offers easy disassembly and cleaning.