Outer seal flushing

Reservoir— Holds the outer seal flush liquid. 

Outer Seal Flush—Cools and lubricates the outer seal faces. 

Inner Seal— Prevents the inner seal flush liquid from escaping along the shaft into the space between the inner and outer seals. 

A dry or nitrogen barrier seal is typically used as the outer seal on a double mechanical seal (see Fig. 37.1). Double mechanical seals are used when the process fluid is environmentally objectionable or above its auto-ignition temperature. The nitrogen barrier seal replaces the reservoir fluid providing seal flush lubrication to the outer seal in the more conventional double mechanical seal. 

Polyester. Poly(ethylene terephthalate) [25038-59-9] (PET) polyester film has intermediate gas- and water- vapor barrier properties, very high tensile and impact strengths, and high temperature resistance (see Polyesters, thermoplastic). AppHcations include use as an outer web in laminations to protect aluminum foil. It is coated with PVDC to function as the flat or sealing web for vacuum/gas flush packaged processed meat, cheese, or fresh pasta. 

Flush Docks. These are constructed flush with the warehouse floor and with the outer wall of the building. This type of dock is generally built at a height above the outside grade level to accommodate the height of the vehicles to be serviced. Where the terrain is flat, ramps down to the docks are usually provided. This type of dock is normally provided with dock seals for weather protection. Also typical are dock leveler installations to accommodate minor differences in the heights of vehicle load beds. 

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