First letter: balanced (B) or unbalanced (U).
The second letter: single face (S); double seal without pressure (i.e., the seventh version of the so-called "tandem seal") (T); or double seal with pressure (i.e., the seventh version of the so-called "double face seal") (D).
The third letter: sealing plate (i.e., sealing gland) type (P = ordinary, without throttle bushing; T = throttle bushing type, with a rapid cooling, leakage of liquid and (or) liquid discharge holes; A = auxiliary sealing device, the type needs to be specified).
The fourth letter: pad (seal ring) material (see table 1).
Fifth letter: end face material (see Table 2).
For example, a code for the BSTFM seal, is a balanced, single face, equipped with a throttle bushing seal plate mechanical seals, static sealing ring cushion material for fluorine rubber (FKM), dynamic sealing ring and the bushing between the cushion of fluorine rubber (FKM), dynamic and static ring end of the face of the sub-material for the carbon on the 2 type tungsten carbide. Seal materials other than those listed above should be coded as X and specified in the data sheet.
Note: a: For minimum and maximum ambient or pumping temperatures, consult the manufacturer.
b: For non-oxidising atmospheres, the maximum temperature is 870°C (1600○F); ask the manufacturer.
Calculation formula for Celsius temperature (℃) and Fahrenheit temperature (○F):
Celsius temperature (°C) = (Fahrenheit - 32) x 5/9.
Fahrenheit temperature (○F) = Celsius temperature × 9/5-32
Notes on Mechanical Seals.
Unless otherwise specified, the spring material for multi-spring seals must be Hastelloy C (Hastelloy C). Spring material for single spring seals must be austenitic stainless steel (AISI Type 316 or equivalent). Other metal parts must also be austenitic stainless steel (AISI Standard Type 316 or equivalent) or other corrosion-resistant materials suitable for the conditions of use, except for metal bellows, which, if used, must be of a material recommended by the seal manufacturer in accordance with the conditions of use. The corrosion rate of metal bellows shall be less than 50 μm (2 mils, mils) per year.
Unless otherwise specified, the seal between the seal plate (i.e., seal gland) and the seal chamber shall be a Viton O-ring with a service temperature of less than 150°C. The Viton O-ring shall be used if the temperature is greater than 150°C or if the seal gland is not used. If the temperature exceeds 150°C or more or if specified, a graphite-filled austenitic stainless steel worm-wound gasket must be used. This worm-wound gasket must be able to withstand the full temperature of the pumped fluid (i.e. without cooling).
The metal sealing ring should not take a spray-plated overlay in place of the integrated sealing end face.
If the pumping temperature exceeds 175 ° C, pump manufacturers and seal manufacturers should be jointly negotiated on the seal end face to take the cooling flushing fluid or one end of the seal chamber does not pass the seal chamber using a constant flow of cooling water chamber.
Mechanical sealing gasket (gasket) temperature limit should be in accordance with the provisions of Table 3.
