Taylor-Wharton Microbulk Tanks - Manual (Page 14)

TW-407 Rev.-
12
External Pressure builder, and Economizer Circuit
The pressure builder(PB) inlet circuit provides pressurized cryogenic liquid to an external pressure
builder. Opening the PB Inlet Valve (V-7) allows liquid, driven by the pressure within the vessel, to flow
into the external pressure builder. The pressure builder uses heat from the ambient air to convert the
liquid into a gas and warm it.
The economizer circuit reduces product loss due to normal evaporation of the liquid within the vessel.
The pressure builder outlet valve (V-6) and the economizer circuit isolation valve (V-5) must be open for
the circuit to function. The economizer regulator (PCV-2) opens when the pressure within the vessel
exceeds the economizer set point. This allows gas from the top of the vessel to flow into the vaporizer
circuit/ liquid withdrawal. Provided that gas from the vaporizer is being withdrawn for use, the vessel
pressure will be reduced. The primary safety valve (SV-2) will be prevented from opening, avoiding
product loss.
The economizer circuit may be isolated for maintenance without emptying or depressurizing the ves-
sel. Closing the pressure builder outlet valve (V-6) and the economizer circuit isolation valve (V-5) iso-
lates the circuit.
Figure 5: External Pressure builder, and Economizer circuit highlighted
V-5
PCV-2
SV-2
V-6
V-7
External Pressure builder, and Economizer Circuit