MRC YDZ-100K Operating Manual Download Page 5

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When the inner container is filled with liquid nitrogen, the exhaust valve, the liquid inlet/outlet
valve and the pressure increasing valve are closed and the lock nut is tight. Under above
conditions, in case of no leakage, due to heat transfer from the container shell to the boosting
pipe, partial liquid nitrogen entering into the pipe will be vaporized due to heat absorption. When
the pressure increasing valve is opened, the vaporized nitrogen will enter into the space above
the liquid level of the liner through the valve immediately and meanwhile the liquid nitrogen in the
container liner will enter into the boosting pipe continuously for heat absorption and vaporization.
Since the volume of the vaporized nitrogen is over 600 times that of liquid nitrogen, a large
amount of nitrogen obtained after vaporization of a little liquid nitrogen will enter into the liner
through the opened pressure increasing valve continuously. As the nitrogen intake increases,
nitrogen accumulated in the space above the liquid level of the inner container starts to generate
a pressure on the inner container wall and the liquid level gradually. When the value of the
pressure gauge reaches 0.02MPa, the liquid inlet/outlet valve will be opened and liquid nitrogen
will be discharged through the drain pipe.

①

Liner: It is used to fill liquid nitrogen.

②

Locking nut: The seal of the liquid nitrogen filling port is threaded and equipped with a low

temperature resistant PTFE seal ring to prevent nitrogen leakage and pressure reduction.

③

Exhaust valve: It shall carry out venting and pressure reduction based on needs. When the

screw plug at the liquid nitrogen filling port is unscrewed, first the exhaust valve must be opened
for venting and pressure relief. When the container is out of use, this valve shall not be opened.

④

Pressure increasing valve: When it is opened, the pressure of the liner will rise. When it is out

of use, it shall be closed tightly.

⑤

Pressure gauge: It is used to indicate the pressure of the liner.

⑥

Liquid inlet/outlet valve: It shall be connected with the liquid hose to fill liquid nitrogen into the

tank body or it shall be used as the makeup tank to fill liquid nitrogen into other container.

⑦

Safety valve: The liner pressure shall be controlled below the maximum working pressure;

once the liner pressure exceeds the maximum working pressure, it will be opened automatically
to vent gas and release pressure. (The pressure shall not be too high frequently; otherwise it will
result in damages of the safety valve.)

⑧

Vacuum sealing joint: It is the gas vent of the vacuum sandwich in the manufacturer of the

container, and it is an important part used to obtain vacuum; once the liner leaks and the
sandwich generates an internal pressure, it protects the liner and the shell from pressure release.

⑨

Pressure maintaining valve: When the pressure in the container is lower than 0.07Mpa, the

pressure maintaining valve will be opened automatically for boosting. When the pressure in the
container is higher than 0.07Mpa, the pressure maintaining valve will be closed automatically to
stop boosting (configured for K series products).

3. Self-boosting Principle

4. Main Functions of Various Parts and Components

Fig. 3 Schematic Diagram of Valve (K series)

The quantity of YDZ-100K safety valves is one.

Pressure

maintaining valve

Digital display level

meter

Pressure

increasing valve

Liquid inlet/outlet

valve