Amico Automatic Cryogenic Liquid Solenoid Manifold - Manual (Page 7)

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Description of the Manifold
LIQUID TANKS
Liquid cylinders contain the product in a liquid state inside of the container. The liquid has to be converted to gas before
entering the manifold. This can be done by the container VIA the internal vaporizers, or in a high or low flow situation
with an external vaporizer. The contents of the liquid container can only be measured by weight. A gauge on the tank,
or simply rocking the tank to determine its weight. The contents of the tanks cannot be measured by the pressure
output. The gauges on the manifold for bank pressure do not indicate the amount of product inside the liquid tanks.
GAS FLOW THROUGH THE MANIFOLD
The liquid containers are divided into two banks. One bank will be the “In-Use” and the other bank will be “Ready” or
secondary bank. The bank In-Use can be either bank with the other bank as secondary, depending on the current status.
As the “In-Use” bank depletes (liquid is gone and pressure drops in that bank) the manifold will switch to the secondary
bank. Indicator LEDs will change to indicate the “In-Use” now as “Empty” and the “Ready” bank will become “In-Use”.
NOTE:
It is common for the pressure on the empty bank to increase and give the false indication that the tank is full. Always check
contents of tanks via weight and float gauge on the tank.
The “Empty” tank can then be replaced with a full one. The manifold will not reset until the “Empty” bank is replaced and the
“Push to Reset” button is pressed. At this time the status is changed from “Empty” to “Ready”. That bank is now the secondary
bank. The “Push to Test” reset should not be pressed until the empty tank has been replaced with a full one.
During normal operation this sequence of alternation will change, the “In-Use” and “Ready” banks from right hand to left
hand banks back and forth as tanks get depleted.
Depending on the amount of gas usage the pressure building valve on the tank “In-Use” may need to be left open. This
allows the tank to convert adequate liquid to gas for the higher flow needed. This will depend on the facility’s usage. This will
normally cause frosting on the outside of the container indicating the proper operation of the pressure builder. Occasional
venting of gas on the tank to relieve excessive pressure is normal and can be expected.
RESERVE (HIGH PRESSURE) BANK
The high pressure reserve bank is used to back up the liquid tanks. The reason is that sometimes the liquid tanks (both
banks) could run empty and the personnel using the system does not know how to determine the amount of liquid
content inside the tanks.
When the liquid tanks run empty, the pressure inside the manifold will drop (in the case of OXY, CO2 & N2O below 150
PSI and NIT below 275 PSI). At 80 PSI for OXY, CO2 & N2O and 180 PSI for NIT, the High Pressure Reserve manifold will
start to supply gas. An alarm from the Reserve In-Use pressure switch (set at 85 PSI for OXY, N2O & CO2 and 190 psi for
NIT) will be activated. The Reserve header has a reserve low pressure switch (to be set at 1100 PSI for OXY, NIT & AIR and
500 PSI for CO2 & N2O) that will ensure the Reserve Header has adequate volume to supply the facility until the liquid
tanks are replenished. The reserve high-pressure tank when full is usually around 2300 psi for OXY, NIT & AIR and 800
PSI for CO2 & N2O.