
UNIBLOC-PD Operation & Service Manual: PD600-677 19
ROTATING SEAL FACES (primary)
ROTORS & PINS
ROTATING SEAL FACE O-RINGS (primary)
STATIONARY SEAL FACES (primary)
ROTOR HOUSING
SHAFTS
BEARING HOUSING
STATIONARY SEAL O-RINGS (primary)
STATIONARY SEAL FACES (secondary)
STATIONARY SEAL FACE O-RINGS (secondary)
ROTATING SEAL FACES (secondary)
ROTATING SEAL FACE O-RING (secondary)
RETAINING RINGS
RETAINING RING O-RINGS
REAR VEW- ROTOR HOUSING
FRONT VEW- ROTOR & BEARING HOUSING
REAR ROTOR HOUSING STUD NUTS
fig. 4.7
4.4.3 Double Mechanical Seal- MODELS: PD600, PD650, PD675
(reference fig. 4.7)
This type of shaft seal is used in most applications with products that have a viscosity of less than 14,000 cPs. The
maximum rotational speed of this seal is 600 rpm and the maximum service pressure is 20.7 bar (300 psig). The
flushed double mechanical seal uses the same Rotating Seal Faces (primary), Stationary Seal Faces (primary),
O-rings, Retaining Rings, and Pins as the single mechanical seals discussed in section 4.4.2. See section 3.3.1 for
more information about flushing systems. The seal can be serviced without removing the Rotor Housing.
4.4.3.1.1 Double Mechanical Seal Removal
(reference figs. 4.1, 4.7)
Slide the stainless steel
Rotors
off the shafts. If the rotors will not slide off they can be removed simultaneously with
the
Rotor Housing
. Unless they are being replaced,
DO NOT USE PLIERS OR CHANNEL LOCKS TO REMOVE
THE ROTORS. THEY WILL BE DAMAGED.
The
Rotating Seal Faces (primary)
,
Pins
, and
Rotating Seal Face
O-rings (primary)
are assembled inside the
Rotors
and will slide out with them. Slide the
Stationary Seal Faces
(primary)
,
Stationary Seal O-rings (primary)
,
Stationary Seal Faces (secondary), Stationary Seal Face O-rings
(secondary), Rotating Seal Faces (secondary),
and
Rotating Seal Face O-rings (secondary)
out of the
Rotor
Housing
. To avoid damage, handle and store the loose
Rotating Seal Faces
and the
Stationary Seal Faces
so that
their lapped sealing surfaces do not get scratched. If servicing the
Bearing Housing
, remove the
Rotor Housing
by first loosening the
Rear Rotor Housing Stud Nuts
. Use a hoist and eye bolt to support the
Rotor Housing
. Tap
on the ports with a rubber mallet and pull the
Rotor Housing
off. Unless being serviced, the
Retaining Rings
may
remain attached to the
Rotor Housing
.
4.4.3.1.2 Double Mechanical Seal Installation
(reference figs. 4.1, 4.7, 4.15)
Clean all components prior to installing the seals. If the
Rotor Housing
was removed, attach it to the
Bearing
Housing
first. Make sure
Retaining Rings
are attached to the
Rotor Housing
. Using an eye bolt, hoist the
rotor housing on the
Dowel Pins
(see fig. 4.15 on pg. 24) and slide it on, while at the same time threading on
the
Rear Rotor Housing Stud Nuts
. Tap the
Rotor Housing
with a rubber mallet to seat it properly against the
Bearing Housing
. Tighten the
Rear Rotor Housing Stud Nuts
in a cross pattern. Slide the
Rotating Seal Faces
(secondary)
with
Rotating Seal Face O-rings (secondary)
installed onto the
Shafts.
Place the
Stationary Seal
Faces (primary)
against the
Stationary Seal Faces (secondary)
so that the pins slide into the slots. Moisten the
Stationary Seal Face O-rings
with water or coat them with a lubricant that is acceptable for contact with the product.
Slide these components in the rotor housing bores. If removed from the rotors, lubricate
Rotating Seal Face O-rings
and slide them in the rotors together with the
Rotating Seal Faces (primary)
locating them on the seal pocket
Pins
.