Page 282 - The Tribology Handbook

Mechanical seals B24

Table 24.8 Selection of materials for aqueous products
Suitable seal ring materials
0 jir corrosion resistance* P
0

Product

Acetic acid 18/8 stainless steel Up to 100°C only
.4mmonia liquid 17/2 stainless steel Use double seal indoors
Ammonium carbonate 17/2 stainless steel Avoid crystallking conditions at seal
Ammonium chloride 18/8 stainless steel Avoid crystallising conditions at seal.
Use Monel spring
Ammonium hydroxide 18/8 stainless steel
Beer 17/2 stainless steel Use V packings above 100°C
Brine (calcium 'chloride) 18/8 stainless steel Use Monel spring and V packings
above 100°C
Brine (sodium chloride) 18/8 stainless steel Use V packings above 100°C
Calcium carbonate 17/2 stainless steel Avoid crystallising conditions at seal
Calcium chloride up to 100°C 18/8 stainless steel Avoid crystallising conditions at seal.
Use Monel spring
Carbon disulphide 18/8 stainless steel Use V packings above 100°C
Citric acid up to 50% conc. 18/8 stainless steel
Citric acid above 50% conc. 17/2 stainless steel Use Hastelloy seal ring
Copper sulphatle 18/8 stainless steel Avoid crystallising conditions at seal
Use V packings above 100°C
Dye liquors 18/8 stainless steel May require P packings on occasion
Hydrogen peroxide 1818 stainless steel Use Hastelloy seal ring
Lime slurries 18/8 stainless steel Use clean injection
Lye (caustic) 18/8 stainless steel
Milk 17/2 stainless steel
Paper stock 18/8 stainless steel Use clean water injection with neck
bush restriction
Phosphoric acid &20% conc. 18/8 stainless steel
Phosphoric acid 20115% conc. 18/8 stainless steel
Phosphoric acid 45-100% conc. 18/8 stainless steel
Potassium carbonate 17/2 stainless steel Avoid crystallising conditions at seal
Potassium dichromate 18/8 stainless steel Avoid crystallising conditions at seal
Potassium hydroxide up to 30% 18/8 stainless steel Avoid crystallising conditions at seal
conc.
Potassrum hydroxide 30% to 18/8 stainless steel Avoid crystallising conditions at seal
100% conc.
Sewage 18/23 stainless steel Avoid solidification at seal. Use clean
injection
Sodium bicarbonate 17/2 stainless steel Avoid crystallising conditions at seal
Sodium carbonarte 18/8 stainless steel Avoid crystallising conditions at seal
Sodium chloride 18/8 stainless steel Avoid crystallising conditions at seal.
Use Monel spring
Sodium hydroxide up to 10% 21 * * * * * E 18/8 stainless steel Avoid crystallising conditions at seal
conc.
Sodium hydroxide 10% conc. 21 P Hastelloy Use Hastelloy seal ring avoid
and above crystallising conditions at seal
Sodium sulphate 21 * * * * * N 18/8 stainless steel Avoid crystallising conditions at seal
13 * *
Sulphur dioxide liquid 21* * * * * * * * * E 18/8 stainless steel
Water % N 17/2 stainless steel E packings up to 150°C
Water (dernineralised) 21 * * * * * * N 18/8 stainless steel
Water (boiler feed) 21 * * * * * * N 18/8 stainless steel
Water (sea) 21 * * * X * * N 18/8 stainless steel
E = Ethylene propylene synthetic rubber
N = High Nitrile synthetic rubber
Seal Packing code V = Viton A fluorocarbon elastomer
P = PTFE or perfluoro-elastomer or graphite

Unless otherwise stated in remarks column PTFE can be used as the seal packing between - 100°C and 250°C.
To avoid crystallising conditions at seal use the quench feature or clean solvent injection into the seal chamber through the circulation
connections.
B24.6