Of all the fluids that can be pumped, adhesives are one of the hardest to work with. It is very common for adhesives to build up around the packing gland on a pump, causing damage to the shaft and premature failure of the thrust bearings. This is mostly due to the physical properties of adhesives, but there are 5 easy ways you can avoid the mess and help prevent adhesive buildup.
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Use Teflon packing
It is quite universally suitable for viscous or corrosive liquids.
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Flush through the lantern ring
A flush to the packing area can help keep adhesives from getting into the packing rings and setting up. This can assist in reducing the amount of torque required by the pump during operation as well as breakaway torque at start-up.
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Use a hardened shaft
Adhesives tend to have higher viscosities and can be abrasive. Hardened shafts can significantly extend the life of the pump in these cases.
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Install a suckback to reduce pressure on the packing
A suckback line reduces pressure in the packing area and also has a tendency to keep circulation through the stuffing box area. This can help with adhesives by not allowing the liquid to stagnate and set up.
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Carefully use mechanical seals
Before pursuing this option, you should consult an engineer with extensive experience in seal selection!
Concern should be used with mechanical seals because once a pump is run, adhesive can set between the stationary and rotating faces of the seal. If the torque required to break this sticking is large enough it could result damaged mechanical seal faces, motor tripping on high amps, or damaged shaft/pump components.
Pumping adhesives isn’t for the beginner. If it were a competition, adhesives would win the award for “most difficult to work with”. But if you follow these 5 steps, you will have a better chance at success.
For more tips and tricks to pumping adhesives, download our Engineer’s Guide to Pumping Adhesives. Or if contact us if you are in Wisconsin or Upper Michigan and need local help.