The proper installation and maintenance of packing to seal a pump
shaft is not difficult but must be properly done to provide good pack-
ing and pump shaft sleeve life. All packing must be allowed to leak.
This leakage is the only lubrication for the packing and additionally
provides cooling to remove part of the frictional heat built up
between the shaft sleeve and the packing. Failure to allow sufficient
leakage will result in short packing and shaft sleeve life and
increased power consumption of the pumping unit. It is entirely possi-
ble to stall a centrifugal pump by clamping the packing gland down.
Dean pumps are shipped from the factory without packing in the
seal chamber. A complete set of die molded packing specified for
the service is shipped with the pump in a separately labeled carton.
The pump seal chamber must be properly packed before the pump
is put into service.
The seal chamber may be packed either with or without a lantern
ring (also known as a seal cage or lantern gland) as the service of
the pump dictates. When the pump section pressure is above 100
psig a lantern ring is not recommended. When the pump is a self-
priming type, the lantern gland should be used to provide a means
to seal against air leakage into the pump during the priming cycle.
PURPOSE OF LANTERN RING
Lantern rings are made of Teflon or suitable metal as the service
demands. They are of split construction and may be easily installed
or removed without disassembling the pump. A lantern ring is used
in the seal chamber with packing for these reasons:
1) To permit the introduction of a sealing liquid into the seal chamber
to prevent leakage of air into the pump through the packing when
the pump suction pressure is less than atmospheric pressure. The
sealing liquid may be from an internal seal connection or from an
external source. This is required on self-priming pumps.
2) To permit introduction of grease, oil or other suitable lubricant to
the packing to provide lubrication or cooling.
INTERNAL SEAL CONNECTION TO THE LANTERN RING
An internal seal connection is used to inject pumpage from the pump
casing into the lantern ring through the lantern ring connection of the
seal chamber to seal the pump against air leakage as noted above.
It can be used only when the pumped liquid is clean and non-abra-
sive.
The pumped liquid introduced through the internal seal connection to
the lantern ring will not seal the pump against air leakage through
the packing when the pump is idle or on stand-by service.
EXTERNAL SEAL CONNECTION TO THE LANTERN RING
The sealing liquid introduced to the lantern ring may be from a
source external to the pump. It must be introduced at a pressure
above seal chamber pressure and must be non-corrosive, non-abra-
sive and 150°F or less in temperature. The connection is made to the
lantern ring connections on the pump seal chamber.
The lantern ring connection on the pump seal chamber is also used
to introduce grease, oil, or other suitable lubricants to the lantern
ring.
LANTERN RING NOT USED
When the pump suction pressure is above atmospheric pressure or
the seal chamber is pressure sealed (no impeller balance holes) and
neither internal nor external liquid or lubricant is required to the
packing, the lantern ring is not used and the seal chamber is packed
full with rings of packing.
PACKING INSTALLATION
These instructions apply to the conventional woven, braided, folded,
and wrapped packings. Packings of multifilament Teflon, braided
carbon filament, compressed carbon sheet, and other special types
or materials may require special installation techniques.
The way in which the packing is installed in the seal chamber is
important to the good service life of the packing and the shaft
sleeve. Incorrect installation will lead to excessive leakage and may
cause higher power requirements.
The use of a packing tamper (split bushing) is recommended to
properly seat the packing rings. Such a tool is easily made from
wood or metal in the form of a hollow cylinder. The inside diameter
must be slightly larger than the shaft sleeve and the outside slightly
smaller than the seal chamber bore. Split the piece lengthwise to
allow insertion in the seal chamber. More than one length of pack-
ing tamper may be necessary. Suit the lengths to the particular
pump.
All packing rings furnished by Dean Pump are die-molded to fit the
seal chamber. To place a ring on the shaft sleeve, open the ring at
the split at the right angle to the plane of the ring. This will best
retain the molded form and avoid distortion. Successive rings should
be installed with the joints at 90° intervals.
Foil wrapped packing must be installed with the foil laps running in
the direction of shaft sleeve rotation on the inside of the ring.
Metallic packing should be lubricated, on the wearing face only,
with a dry graphite lubricant before insertion.
PACKED SEAL CHAMBER WITH LANTERN RING
PACKED SEAL CHAMBER WITHOUT LANTERN RING
S = When soft packing rings are furnished in a set with metallic rings, install the soft
rings in the locations marked “S”.
23
INSTALLATION AND MAINTENANCE OF SEAL CHAMBER PACKING
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