Milton Roy MILROYAL D, Инструкция по эксплуатации

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15 Instruction Manual
SECTION 5 - MAINTENANCE INSTRUCTIONS-LIQUID END 7/16” AND 5/8” DIAMETER PLUNGERS
5.5.1 Types of Packing
There are two general types of packing used in this
pump, automatic and compression.
Automatic type packing is made up of a series of
shaped rings which have sealing lips that react
with applied hydraulic pressure to form a good fluid
seal against both the moving plunger and walls
of the stuffing box. This type packing is generally
preferred over the compression type because of
its lower friction against plunger and somewhat
self-adjusting characteristics which allow it to
compensate for wear and maintain good sealing.
Automatic packing must never be adjusted so
tightly that it loses its capability to properly flex
during operation. It is seldom necessary to adjust
this type of packing any more than finger tight.
Packings of square or round cross section which
must be firmly compressed in the stuffing box are
known as compression types. These are available
in many materials, and are usually used only
when the somewhat limited materials of automatic
type are not compatible with the pumped fluid.
They depend on mechanical compression in stuffing
box by the follower and gland cap for fluid sealing.
If compression type packing is too tightly
compressed against the moving plunger, frictional
force will be reflected back through the drive
mechanism as an overload, or develop sufficient
localized heat to destroy sealing surfaces of both
plunger and packing.
Compression type packing is very dependent on
proper break-in to develop a good sealing surface.
5.5.2 Replacing Packing
1. To properly replace packing, it is necessary to
remove liquid end from pump.
2. Loosen No. 430 Gland Cap (do not remove).
3. Remove the two No. 270 screws which attach
liquid end to pump housing.
4. Pull liquid end straight OFF pump and plunger,
taking care not to damage plunger by bending.
Inspect plunger for scoring or pitting and replace
if necessary.
5. Remove No. 430 Gland Cap and No. 427 Gland
follower. Inspect No. 428 gland bearing liner
and replace if worn. Remove rear section of
packing with a small hook or corkscrew device,
taking care not to scratch wall of stuffing box.
Remove No. 419 lantern ring, remaining forward
section of packing and No. 418 neck ring.
Thoroughly clean lantern ring, neck ring, and
stuffing box of all foreign matter.
6. Refer to figure 5 . It can be seen that the total
packing set consists of a neck ring, a lantern
ring, a gland follower, and two separate sets of
packing material. The forward set of packing
(nearest check valves) is intended to seal
against pumped fluid. The rear set is intended
to seal lubricant in and force lubricant to flow
forward at injection. A new packing set should
be made up to the following dimensions with a
tolerance of +0 to -1 packing ring.
a. Length of neck ring and front set of packing
(automatic packing to include one male and
one female adapter) 1 1/2” (38 mm).
b. Total overall length of both front and rear
packing sets, neck ring, and lantern ring
(including adapters for automatic type
packing) 2 3/4” (70 mm).