Mechanical Seal; General; Preparation; Special Tools - Johnson Pump TG GS2-25 Instruction Manual

4.6

Mechanical seal

Guidelines for assembly and adjustment of the mechanical seal – pump types GS.
4.6.1

General

• All personnel responsible for maintenance, inspection and assembly must be
adequately qualified.
• Use specific instructions coming with the mechanical seal which is to be assembled/adjusted.
• The assembling and adjusting of mechanical seals must be performed in a clean workshop.
• Use technically appropriate tools that are in good condition. Handle them correctly.
4.6.2

Preparation

Check if the mechanical seal to be mounted has the appropriate size and construction and verify if
it can be assembled. The short EN12756 (DIN24960) single mechanical seal can be built in. The
mechanical seal is set against the rotor shoulder.
TG GS pump size
Shaft diameter
Short EN12756 (DIN24960)
L-1K (short KU)
Dimensions in mm
4.6.3

Special tools

• Conical protection bush (9010)
• Shammy
4.6.4

General instructions during assembly

• Do not touch the mechanical seal faces with hand or fingers. Fingerprints can make the
mechanical seal untight. Clean the seal faces if necessary. Use a shammy.
• If the mechanical seal faces are made of non self-lubricating material, it is recommended to
lubricate the faces a little with the pumped liquid or with thin oil. Do not use grease!
• Lubricate the O-rings when assembling. Take care of compliance of the lubricant and the
rubber material. Never use mineral oil using EP rubber O-rings.
• When fitting PTFE sealings the shaft must be very smooth. Assembly of solid PTFE sealings can
be facilitated by heating the stationary ring in water at 100°C during 15 minutes.
Pre-assemble the rotary ring on a dummy shaft and heat both ring and shaft in water at 100°C
during 15 minutes. Then let everything cool off. To be tight, PTFE seals must rest for appox.
2 hours so that the O-ring remains in its new shape.
• In cases where the mechanical seal is provided with fixing screws to fix the rotating part on
the shaft, it is recommended to screw out the fixing screws, degrease both holes and screws
and lock them with Loctite (usual type 241 or heat-resistant type 648).
4.6.5

Assembly of the rotating part

• Lubricate the shaft a little with a lubricant.
Attention for EP rubber: do not use mineral oil!
• Protect the sharp edges of the shaft with
tape or another protecting tool.
• Use a conical assembling bush (9010)
on the shaft step (see figure).
• Push the rotating parts against
the rotor shoulder.
• Provide the set screws with a drop heat-resistant Loctite and fit the set screws in the rotating
part. Tighten the screws.
52
2-25 15-50 58-80
6-40
2-32 23-65 86-100
18 22 35 40
KU018 KU022 KU035 KU040
37.5 37.5 42.5 45
185-125
55
KU055
47.5
9010
A.0500.501 – IM-TGGS/05.01 EN (03/2013)