??(1) high temperature, such as the bottom of heat pumps, heat carrier pumps, catalytic slurry pump, recycle oil pump, etc., which is characterized by the material strength at elevated temperatures drop, the media sometimes vaporization, solidification, crystallization, seals will be deformed, rubber aging, spring failure, thimble shedding. At this time of the seal requires use of high temperature materials, take the insulation and cooling, pay attention to the movable ring sliding at high temperatures, can be bellows-type seals.

??(2) at low temperatures, such as ammonia pump to pay attention to the media vaporization and dry friction, the air seal is formed into ice water. In addition to low-temperature-resistant materials, it requires the use of cold in order to prevent icing. Drying gas may be introduced in the gland, taking care to seal

??(2) cryogenic pump seals, such as methane, pumps, etc., at a temperature from 95 to 100%, while the inlet pressure was as high as 3MPa, methane and easily vaporized, poor lubrication, once the leak in the seal of the frost. Selection of a refinery double-end balanced mechanical seals, rotary type, multi-flow internal spring, both sides share a spring ring, stationary ring ring corresponds carbide graphite material selection. Selection sealing liquid refrigerant oil temperature at 5 ? and down. The key is to have a special sealing liquid and automatic control auxiliary devices.

??(3) light hydrocarbon pump seals, typically G or C: 4 and other liquid hydrocarbons. Selection of a refinery single face balanced seal. When the seal chamber pressure is 2MPa less mechanical seal load factor selected O.75 ~ 0.85. In this case the corresponding spring pressure of 0.1 1 ~ 0.2MPa. Static ring material selection of tungsten carbide corresponds graphite. Light hydrocarbon pump seal with self-flushing systems, fluid pressure higher than the seal chamber pressure of 0.1 ~ 0.2MPa. Rinse slightly larger than normal, about 12 ~ 30IMmin.

??(4) high-speed pump seal, generally refers to the outer circumference of the seal ring line speed at 30 ~ 50m / s. High speed pump seal key is static structure should be used, to avoid the adverse effects of high speed centrifugal force on the sealing element performance, reduce the rotational member of the media agitation increases power consumption. Thus multi-use multi-spring, stationary, balanced seal, and the sealing surface is quite narrow, typically about 3mm.