Flowserve Pac-Seal Type 21 User Manual
Installation
Experience In Motion
Instructions
Pac-Seal Type 21 and Type 31
Mechanical Shaft Seal
TM
Description
Pac-Seal Types 21 and 31 feature uniquely designed crimped heads
and hex-torque drive systems that provide a solid engineered advantage
over other seal types. The Type 31 is the Pac-Seal designation for the
Type 21 seal with hard face combination. Generally these are reserved
for severe duty applications, in the Type 21 design envelope. Both Types
21 and 31 are available in double seal congurations and balanced
versions.
Type 21 and Type 31 Nomenclature Figure 1
2816
142
2 157
Part Reference Description
2 Seal Drive/Drive Band
14 Stationary Face/Mating Ring
15 Rotating Face/Primary Ring
16 Spring
28 Shell
126 Gasket/Elastomer Cup/Cup Gasket
15 126
14
142 Retainer/Spring Retainer
157 Bellows Diaphragm/ Elastomer Bellows
2
1 Equipment Check
1.1 Follow plant safety regulations prior to equipment disassembly
including, but not limited to, the following:
• Lock out motor and valves
• Wear designated personal safety equipment
• Relieve any pressure in the system
• Consult plant MSDS les for hazardous material regulations
1.2 Disassemble pump in accordance with equipment manufacturer’s
instructions and remove sealing arrangement.
1.3 Check Seal documentation for seal design and materials of
construction.
1.4 Check shaft or pump sleeve outer diameter (OD), seal working
height, mating ring width, and seal chamber bore to ensure they are
dimensionally within the tolerances shown on the seal assembly
drawing. See Figure 2.
Seal Chamber Requirements Figure 2
Seal Working
Height
Seal Chamber Bore
-0.050 mm (-0.002 inch)
Shaft or sleeve OD
-0.050 mm (-0.002 inch)
• Bearings must be in good condition
• Maximum lateral or axial movement of shaft (end play) = 0.25 mm (0.010 inch) FIM
• Maximum shaft runout at face of seal housing = 0.05 mm (0.002 inch) FIM
• Maximum dynamic shaft deflection at seal housing = 0.05 mm (0.002 inch) FIM
• Verify proper shaft and bore lead in chamfers are present and within specifications.
Difficulty and damage can be observed during seal installation without proper
lead in chamfers.
Sleeve or shaft finish to be
1.6 μm (63 μinch) R or better
Mating
Ring
Width
a
3
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