Notes on the use of Dewars

Use of Dewar Bottles

Dewar bottle supply flow: first make sure that the main pipe valve of the spare dewar set is closed. Open the gas and discharge valves on the dewar ready for use, then open the corresponding valve on the manifold skid attached to the dewar, and then open the corresponding main pipe valve. Finally, open the valve at the inlet of the gasifier, and the liquid is supplied to the user after being gasified by the regulator. When supplying liquid, if the pressure of the cylinder is not enough, you can open the pressurization valve of the cylinder and pressurize the cylinder through the pressurization system of the cylinder, so as to obtain sufficient liquid supply pressure.


The Advantages of Dewar Bottles

The first is that it can hold a large amount of gas at a relatively low pressure compared to compressed gas cylinders. The second is that it provides an easy to operate cryogenic liquid source. Because the dewar is solid and reliable, long holding time, and contains its own gas supply system, using its built-in carburetor and can continuously output up to 10m3/h of normal temperature gas (oxygen, nitrogen, argon), gas high constant output pressure of 1.2mpa (medium pressure type) 2.2mpa (high pressure type), fully meet the requirements of gas under normal circumstances.

The Preparatory Work

1. Whether the distance between dewar bottle and oxygen bottle is beyond the safe distance (the distance between two bottles should be more than 5 meters).

2, there is no open fire device around the bottle, and at the same time, there should be fire prevention device nearby.

3. Check whether dewar bottles (cans) are well connected to end users.

4, check the system all valves, pressure gauges, safety valves, dewar bottles (tanks) using valve fixture should be complete and easy to use.

5, the gas supply system shall not have grease and leakage.

Precautions for Filling

Before filling dewar bottles (cans) with cryogenic liquid, first determine the filling medium and filling quality of gas cylinders. Please refer to the product specification table for filling quality. To ensure accurate filling, please use the scale to measure.

1. Connect the cylinder inlet and outlet liquid valve (DPW cylinder is the inlet liquid valve) with the supply source with the Vacuum Insulated Flexible Hose, and tighten it without leakage.

2. Open the discharge valve and inlet and outlet valve of the gas cylinder, and then open the supply valve to start filling.

3. During the filling process, the pressure in the bottle is monitored by the pressure gauge and the discharge valve is adjusted to keep the pressure at 0.07~ 0.1mpa (10~15 psi).

4. Close the inlet and outlet valve, discharge valve and supply valve when the required filling quality is reached.

5. Remove the delivery hose and remove the cylinder from the scale.

Warning: Do not overfill gas cylinders.

Warning: Confirm the bottle medium and filling medium before filling.

Warning: It should be filled in a well-ventilated area as gas build-up is very dangerous.

Note: a fully filled cylinder can rise in pressure very quickly and may cause the relief valve to open.

Caution: Do not smoke or go near a fire immediately after working with liquid oxygen or liquefied natural gas, as there is a high possibility of liquid oxygen or liquefied natural gas splashing on clothing.

HL Cryogenic Equipment

HL Cryogenic Equipment which was founded in 1992 is a brand affiliated to Chengdu Holy Cryogenic Equipment Company in China. HL Cryogenic Equipment is committed to the design and manufacture of the High Vacuum Insulated Cryogenic Piping System and related Support Equipment.

For more information, please visit the official website, or email to

Post time: Oct-16-2021