Options
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Algas-SDI Operations & Maintenance Manual P/N 52632
7-55
Figure 29 - Installation Schematic
Installation (B).wmf
ECONOMY OPERATION INSTALLATION
The following installation schematic depicts the economy operation option.
Please take a moment to review the layout. The option incorporates a
downstream vapor by-pass line, liquid inlet pressure switch, and additional
circuitry for the control system.
When pressure in the storage tank is higher than the inlet pressure switch set
point 50 psig (3.52 kg/cm
2
), the switch is “OPEN” and the vaporizer is not
energized. Vapor demand is consequently met by natural vaporization from the
storage tank through the bypass vapor line. When pressure in the storage tank
is less than the inlet pressure switch set point, the switch “CLOSES” and the
vaporizer is energized. The inlet solenoid valve to the vaporizer will open. Liquid
propane then enters the vaporizer, is vaporized, and meets the vapor demand of
the distribution system. The first stage regulator is set to 2 to 4 psig (0.14 - 0.28
kg/cm
2
) higher than the bypass vapor regulator. This restricts all vapor flow from
the storage tank when the vaporizer is on. This allows the storage tank to rebuild
sufficient pressure to open the inlet pressure switch and de-energize the
vaporizer. The Economy Switch will re-open when the tank pressure reaches 70
psig (4.92 kg/cm
2
). Natural vaporization then resumes, supplying vapor through
the bypass vapor line. Both of the operating pressure set points are adjustable.