Dewar filling principle

Dewar filling principle: use the pressure difference between the storage tank and the Dewar to fill directly.
 
　　 1. Confirm whether the medium to be filled is the same as the medium in the Dewar. If it is different, the Dewar flask must be completely emptied and filled.
 
　　Warning: Confirm the medium in the bottle and the filling medium before filling.
 
　　 2. Determine the correct total filling weight, which is the sum of the empty bottle weight, the filling pipe weight shown on the Dewar bottle nameplate, and the maximum filling weight found in the "Performance Parameter Table". It is strictly forbidden to overfill the gas cylinder.
 
　　 3. Use a special delivery hose to connect the Dewar inlet and outlet valve to the supply source, and tighten without leakage.
 
　　 4. Open the vent valve and the inlet and outlet valve on the Dewar, open the outlet valve on the large storage tank and the shut-off valve on the filling pipeline to start filling.
 
　　Warning: It should be filled in a well-ventilated place, because the accumulation of gas is very dangerous.
 
　　 5. During the filling process, monitor the pressure in the bottle through a pressure gauge and adjust the discharge valve to maintain the pressure at 0.07~0.1MPa (10~15 psi).

 

　　 6. During the entire filling process, you must pay attention to observe the pressure of the inner container of the Dewar, and adjust the "vent valve" to maintain the pressure of the inner container of 10-15Psig (excluding CO2 liquid).
 
　　 7. When the filling liquid reaches the total weight of the filling, close the inlet and outlet valve and vent valve on the Dewar flask.
 
　　 8. Close the shut-off valve on the filling pipeline and open the vent valve on the filling pipeline to drain the residual liquid and gas in the filling pipeline
 
　　 9. Remove the delivery hose and remove the Dewar from the scale.
 
　　Note: The pressure of a fully filled Dewar rises very quickly, which may cause the safety valve to open.
 
　　Caution: After working on liquid oxygen or liquefied natural gas, since liquid oxygen or liquefied natural gas is likely to be splashed in clothing, please be careful not to smoke or near a fire.
 
　　Note: When the saturation pressure of liquid carbon dioxide drops to 0.48MPa (70 psi), liquid carbon dioxide will form solid dry ice. Therefore, when using 175L/195L/210L and 499L Dewar cylinders to fill liquid carbon dioxide, the carbon dioxide gas in the cylinder must be pressurized before filling.