Posted by Tarzan on May 16, 2001 at 07:34:52:
In Reply to: Lantern rings and pump packing posted by Brian Buchberger on April 29, 2001 at 18:37:26:
: I have a question what is a lantern ring and what does it do?, I have a centrifugal feedwater pump with packing can i remove the packing and install a mechanical seal, thanks
Everyone has given you good advice already, but I gotta add something...
Mech seals are a wonderful thing, but they tend to fail instantly, so keep a ready supply of spares on hand.
Mech seals are also more sensitive to pump/motor alignment. And you disturb that alignment each time you replace an inboard seal. So learn to perform close alignments.
Keep your old packing glands, lantern rings and other stuff you replace when converting to mech seals...nice to have around when you decide to back-fit.
The lantern ring needs to be positioned directly under the fluid seal line inlet when all packing is installed and compressed. I Roger that most feed pumps operate on a positive head and don't require water seal at the gland, but the lantern ring also provides cooling and lubrication.
Mech shaft seals eliminate the constant leak off and associated corrosion problems you get with packed shafts, but they require longer downtime, further tear down and more critical skills when servicing. So take yer pick and be ready to retro-fit should you decide to.
Ask pump manufacturer first as most now offer same pump with either packed or sealed shaft options...their choice of seal manufacturer is based on their experience with the product.
As a last resort, consider welding the shaft to gland joint...just don't tell the boss I said to.
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