Stuffing Box, Packing And Plunger Assemblies; General; Spring Loaded Packing; J-Style Stuffing Box & Plunger Assembly (Styles 838 And 858) - Pentair MYERS APLEX Series Installation And Service Manual

STUFFING BOX, PACKING AND
PLUNGER ASSEMBLIES

GENERAL

Myers Aplex Series pumps all feature field removable
and replaceable stuffing boxes with plungers separable
from the extension rods.
If desired, the boxes, plungers, and packing units may
be installed (or removed) as a unit assembly, permitting
service outside the pump. All boxes are retained by
four (4) studs and nuts, and are centered in the frame
bore, ensuring correct alignment.
The plungers may also be removed separately (without
box removal) to facilitate repacking. With this option,
the necessary space required to remove plunger, it is
first necessary to remove the extension rod.

SPRING LOADED PACKING

Compression Packing
GLAND RING
GLAND RING
Chevron Packing
Note that the gland is screwed tightly onto the box
and contacts its face. The spring is providing all of the
initial compression and adjustment. No adjustment is
provided by the gland.
Since the force exerted by the spring is contingent on
the space provided for it, the correct lengths of all rings
are essential for good tensioning.
Spring:
A stiff Inconel spring, which closely fits the bore of
®
the stuffing box, is used in this assembly. This spring is
compressed in a vise to the operating length required
plus 0.25" and tied with waxed nylon spot tie cord. The
cord is looped over the ends of the spring through the
coils and tied to maintain the length mentioned above.
Each spring is assembled into the stuffing box. Note
that the spring does not contact the plunger.
Spring-Guide Ring:
Plungers are heavy and the importance of a well-fitted
guide ring that carries this weight is often overlooked.
SPRING GUIDE
SPACERS
PACKING
SPRING
SPRING GUIDE
Discard any guide ring that becomes worn or scored, as
it will then not serve its purpose. It should fit snugly in
the box. Apply oil generously to this ring.
Spring Loaded Packing:
Three (3) rings of chevron or compression packing
are installed next. For compression packing, install
them with the skive intersections 180º apart to
discourage leaking.
Gland Ring:
This ring also fits the plunger and helps support the
plunger weight. Discard it if bore is worn, rough or out-
of-round. Lightly oil the ring before insertion. The gland
ring fits all packing.
J-STYLE STUFFING BOX & PLUNGER ASSEMBLY
(STYLES 838 & 858)
GLAND
RING
BAFFLE
Above depicts Styles 838 and 858 packing correctly
installed with all packing lips facing TOWARD the fluid
pressure. Note that two (2) units of Styles 838 and
858 packing are positioned ahead of the lantern ring,
and one (1) unit is positioned behind it. Thus lubricant
entering the lantern ring is forced toward the pressure.
Throat Bushing:
Plungers are heavy and the importance of a well fitted
throat bushing that carries this weight is often over-
looked. Discard any throat bushing that becomes worn
or scored, as it will not then serve its purpose. It should
fit snugly in the bottom of the box. Apply oil generously
to this ring.
Styles 838 and 858 Packing:
Developed by Utex Industries, Inc., Styles 838 and
858 are a NON-adjustable type packing which depends
solely on hydraulic pressure to energize the sealing
lips. (Gland-tightening forces do NOT energize the
lips.) Tightening and hydraulic end thrust loads are
transmitted entirely through the center support portions
of each ring.
The flattened portions of the rings are large enough
to withstand overtightening. Do NOT attempt to
adjust this type packing. It should be kept thoroughly
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THROAT BUSHING
PACKING SET
PRESSURE
LANTERN RING