180 liter LN2 Supply Tank 3-1
Thermo Scientific
Section 3
Theory of Operation
The various liquid cylinders of the Cryo-Cyl Series have the same general
operating characteristics. Each model of liquid cylinder has the ability to
be filled with a cryogenic product, build pressure inside the vessel, and
deliver either liquid or gas for a specific application.
The following section discusses the theory behind these operations. Later
sections give a step-by-step procedure for the operation on each specific
models of liquid cylinder.
Liquid cylinder operation is done completely with the control valves
located on the top of the tank. The valves are labeled and color coded for
easy identification: Fill/Liquid Valve - blue; Gas Use Valve - green; Vent
Valve - silver; Pressure Building Valve - green.
The schematic, illustrations and Figure C show how the plumbing
circuitry operates for the four major models of liquid cylinders. It is
important that the operators be familiar with the plumbing control valves
and their functions.
PRESS
BUILD
CO
2
6
8
9
4
Figure C.
Plumbing
Cryo-Cyl LP
Item
Plumbing Controls and Function
1
Gas Use Valve – Used for gas withdrawal.
2
Fill / Liquid Valve – Used for filling or liquid withdrawal
operations.
4
Vent Valve – Used to vent pressure.
5
Pressure Control Manifold– Used to automatically main-
tain pressure .
6
Pressure Gauge – Indicates cylinder pressure.
7
Combination Regulator MCR– Used to automatically
maintain pressure.
8
Pressure Relief Valve – Used to limit pressure in the liq-
uid cylinders.
9
Liquid Level Gauge – Used to approximate the liquid
contents of the liquid cylinder.
