Cashco 8900 - Manual

INSTALLATION, OPERATION AND MAINTENANCE MANUAL (IOM) IOM-8900
09-10
SECTION I
I. DESIGN AND FUNCTION:
8900 Series
Emergency Relief Vents
Pressure Only or Pressure/Vacuum
The 8900 Series is classifi ed as an Emergency Relief
Vent (ERV). The design allows it to be used as an
emergency pressure only vent or a pressure/vacuum
vent. This Series of Vents can be constructed as top
guided or hinged design. Depending on the pressure
requirement, vents can be assembled using a stack
of weights or springs to achieve the desired set point
pressure.
The 8900 Series can provide emergency pressure
and vacuum relief beyond that furnished by the
normal pressure/vacuum vent for atmospheric and
low pressure tanks, as well as providing a convenient
access for tank cleaning, inspection and repair.
Emergency Pressure Relief Vents provide relief from
excessive internal pressure which may be caused
by an abnormal condition, such as ruptured internal
heating coils, an external fi re or a failure of the tank
blanketing system. Some Models are also design to
provide emergency vacuum relief as a result of loss
of pressure casued by a break in the tank wall or a
nozzle being dislodged from the base of the tank or
sudden cooling of the tank.
The 8900 Series provides an effective vapor
tight seal when the tank is not under emergency
conditions. If the tank outbreathing requirements
exceed the capacity of the normal pressure relief
vent, under emergency conditions, the pallet opens
to allow escape of the vapors, preventing damage
to the tank due to excessive pressure. The intergal
vacuum vent allows high fl owing relief from the same
unit.
This vent design is rugged but light weight for easy
handling, inspection and maintenance. For Models
8910 and 8920 removal of the pallet assembly allows
unobstructed access to the inside of the tank. For
Models 8930 and 8940 use handle to raise the
weighted pallet assembly and gain access to the
inside of the tank.
Product Selection Guide
Vent Function Guiding Model
Pressure Relief Top Guided
(Spring Loaded)
8910
Pressure/Vacuum Relief 8920
Pressure Relief
Hinged
8930
Pressure/Vacuum Relief 8940