engiflow
best available technology for the
safe & efficient handling of liquids
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ressure variations in storage tanks
Protectoseal pressure/vacuum conservation vents reduce evaporation of tank contents to the atmosphere. The vents are mounted to a flange or pipe that connects to the vapour space of a storage tank. This is the space within the tank above the liquid surface.
The pressure in the vapour space increases or decreases as liquid is pumped into or out of the tank. Atmospheric temperature changes cause an expansion or contraction of the vapours in this space. This again results in a pressure change.
How it works
The breather vents are factory set to customer specifications. The set points for these vents are achieved either by weight or spring loading of the pallet assemblies. This depends on the setting required. The set point is defined as the tank pressure or vacuum at which the force resulting from the tank pressure acting on the pallet assembly equals the sealing force of the pallet assembly and weights. With other words, the pressure at which the vent begins to open.
The pallet assembly in the housing opens when the specific pressure and vacuum level are sensed. Once the excess pressure or vacuum condition has been relieved, the pallet assembly reseals automatically. The tank's vapour space is always maintained within the safe range of its pressure and vacuum operating design limits.
Types
|
series |
type |
pressure/vacuum |
|
end-of-line |
pressure/vacuum |
|
|
pipe-away |
pressure/vacuum |
|
|
in-line |
pressure/vacuum |
|
|
end-of-line |
pressure |
|
|
pipe-away |
pressure |
|
|
end-of-line |
vacuum |
|
|
pipe-away |
vacuum |
|
|
end-of-line |
free vent |
End-of-line vents relieve pressure directly to the atmosphere. Pipe-away and In-line vents have flanged or threaded outlet connections. The vented vapours may be confined and directed through connecting piping for further processing.
Unique air-cushion sealing
The weight loaded vents are provided with the unique air cushion sealing mechanism. A smooth FEP diaphragm bridges a grooved air space in the pallet assembly. The vent seat contacts the diaphragm in the area of the air cushion groove. This provides a resilient sealing joint and consequently very low leakage rates. In addition, the pallet have a peripheral guiding and centre stabilizing stem. This ensures proper alignment and tight seating.
