Unibloc-Pump 54001010P20H6010T12E, Operation & Service Manual

20  UNIBLOC-PD Operation & Service Manual: PD200-576

4.4.2 Flushed Single Mechanical Seal

The flushed single mechanical seal uses the same stationary mating ring, rotating seal nose ring, spring, and o-rings as the single 

mechanical seal discussed in section 4.4.1. The drive collar is different, however. The flushed single mechanical is not available 

for 

UNIBLOC

 200-0, 200, 250, and 275. See section 3.3 for more information about flushing systems.

4.4.2.1 Flushed Single Mechanical Seal Removal

Disconnect the flush tubing from the flush housings (55). Loosen the set screws 

(D) by inserting an allen wrench into the flush housing port holes. Loosen the 

stud nuts (item 43 in Figure 4.4.1). Remove the rotor housing (1) by pulling on 

the ports or by tapping gently with a rubber mallet and lay it rotor cavity down 

so that the seals face up. Do not rock the housing back and forth excessively 

or let it come in contact with the shaft splines. The seals may break. The entire 

seals  with  the  flush  housings  will  come  off  intact  with  the  rotor  housing.  Un

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screw the bolts (32) to remove the flush  housings  (55), the lip seals (56), and 

the flush housing o-rings (37). The remaining seal components may now be re

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moved. To avoid damage, handle and store the loose seal nose rings (B) and the 

mating rings (A) so that their lapped sealing surfaces do not get scratched. To 

remove the lip seals (56), place the flush housings so that they are supported at 

the bolt holes not at the at the o-ring (37) location. This can be done by placing 

the flush  housings, after all other seal parts have been removed, back into the 

rotor housing seal bores.  Push or tap the lip seals with a tube to remove them.   

4.4.2.2 Flushed Single Mechanical Seal Installation

Place the mating ring o-rings (33a) in the rotor housing seal bores. Only lubricate these o-rings with water or alcohol. Push the 

mating rings into the rotor housing so that they seat flat with the step in the housing. Do not use objects that will scratch the 

mating rings’ seal surface to push them in. Check the drive collars (C) for wear at the lip seal location. If a groove is present, the 

drive collars may need to be replaced.  If the lip seals (56) have been removed, place the flush housings (55) so that the o-ring 

groove edges face up. Lubricate the lips and the outer diameters of the lip seals.  Push the lip seals, spring sides facing up, into 

the flush housings with a tube that is the same diameter as the lip seals. Place the o-rings (37) into the o-ring grooves.  Lubricate 

the shafts, the outside of the plastic mounting sleeves, and the drive collars at the lip seal location. Slide the flush housings on the 

drive collars. Slide the flush housings with the drive collars, seal nose o-rings (33b), and the seal nose rings (B), slotted sides first, 

on the plastic mounting sleeves. Align the slots with the pins in the drive collars and push the seal nose rings so that the o-rings 

(33b) seat properly.  Place a product compatible lubricant on the sealing surfaces. Rotate the flush housings so that its port holes 

align with at least one set screw. Lubricate the o-rings (37) and mount the seal cartridge assemblies on the rotor housing. Tighten 

the bolts (32).  

See section 4.4.7 to complete the installation.