Single Mechanical Seal; Unibloc-Pd 200-275 Single Mechanical Seal Removal; Unibloc-Pd 200-275 Single Mechanical Seal Installation - Unibloc-Pump UNIBLOC-PD Series Operation & Service Manual

4.4.1 Single Mechanical Seal

This type of shaft seal is used in most applications with products that have a viscosity of less than 1,000 cPs. The maximum
rotational speed of this seal is 1500 rpm and the maximum service pressure is 13.5 bar (195 psig). The seal materials available are
stainless steel, carbon, silicone carbide, and tungsten. The standard o-rings supplied in these seals are FDA-viton or FDA-EPDM.
These can be replaced with other materials upon request.
UNIBLOC-PD 501 Series has front loaded seals. This seal comes with different seal face combinations. (See drawing G812B for
details.) Maximum shaft rotational speed for this seal is 2.4 m/s (7.8 ft/s) or 800rpm and the maximum service pressure should not
exceed 15 bar (220 psig). Maximum and minimum temperature limits are +160°C (320°F) and -15°C (5°F).

4.4.1.1 UNIBLOC-PD 200-275 Single Mechanical Seal Removal

Loosen and remove the acorn nuts from the Rotor Housing. Loosen the Threaded Studs by locking two M6 nuts against each
other on the exposed threaded stud ends. Remove the Rotor Housing by pulling on the ports or by tapping gently with a rub-
ber mallet. Do not rock the housing back and forth excessively. This can cause the seals to break. Remove the Stationary Seal
Faces and Stationary Seal O-Rings by pulling them out of the rotor housing. Remove the Rotating Seal Faces, the Rotating
Seal O-Rings, and Rotating Seal Washers by sliding them off the shafts. To avoid damage, carefully handle and store the loose
Stationary Seal Faces and the Rotating Seal Faces so that their lapped sealing surfaces do not get scratched.
Shaft Pins
Rotating Seal Washers
Rotating Seal O-Rings
Rotating Seal Faces
Stationary Seal Faces
Wave Springs
Stationary Seal O-Rings
Rotor Housing Pins
Threaded Studs
Rotor Housing
UNIBLOC-PD 200-275 with Single Mechanical Seals

4.4.1.2 UNIBLOC-PD 200-275 Single Mechanical Seal Installation

If missing, insert the Rotor Housing Pins into the rotor housing and the Shaft Pins into the shafts. Coat the shafts and rotor
housing bores with a product compatible lubricant. Place the Rotating Seal O-Rings in the Rotating Seal Face first, and then
the Rotating Seal Washers. Slide the Rotating Seal Rings, slotted side first, onto the shafts. Place the Wave Springs between
the Rotor Housing Pins. Place the Stationary Seal O-Rings in the groove of the Stationary Seal Faces. Align the slots of the
Stationary Seal Faces with the Rotor Housing Pins in the rotor housing. Push the Stationary Seal Faces into the rotor housing,
o-ring side first. Press several times to make sure they slide easily. Place a product compatible lubricant on the sealing surfaces.
Proceed to section 4.4.7 to complete the installation.
UNIBLOC-PD Operation & Service Manual: PD200-576 17