Low Pressure Ambient Vaporizer

Ambient air vaporizers require no external source of energy; and enables vaporization through exchange of heat with the surrounding air. The liquefied gas is vaporized, and warmed to almost the surrounding temperature, and finally led to the users in its gaseous state.

The vaporizers are for use with liquid:

  • Nitrogen
  • Oxygen
  • Argon
  • Carbon Dioxide
  • Nitrous Oxide
  • LNG

Design Specifications

Isisan offers a full range of ambient air vaporizers in different versions and for different applications. Our ambient air vaporizers have the following properties:

  • Designed and manufactured according to PED 97/23/EC;
  • Has CE marking
  • Max. allowable working pressure 40 bar
  • Cleaned for oxygen service
  • Seismic requirements acc. to uniform building code-zone 4
  • Low pressure drop
  • Efficient fin tube design
  • Optimized external and internal surfaces for optimum convection

Vaporizer Options

Ambient air vaporizer options are:

  • Fin tube vaporizers
  • Fan assisted vaporizers

Fin tube vaporizers rely on natural convection while fan assisted models are equipped with an electric motor operated fan to enhance air flow and increase efficiency.

How Do Ambient Air Vaporizers Work?

Since the surrounding air is at a higher temperature than the product; heat from surrounding air is transferred to the product in the vaporizer.

While ambient air vaporizers are in use, it is normal to see a mist forming. This is caused by the moisture in the air, condensing and freezing. The intense cold of cryogenic liquid and the moisture in the surrounding air will create frost and ice will build up on vaporizer tubes, gradually.

For this reason ambient air vaporizers have a limited running time before the frost and ice has to be cleared from the tubes.

The performance of ambient air vaporizers may be impaired during prolonged periods of severe cold weather. This will create additional frost and ice formation, causing a performance drop.

Method of Heat Transfer

Fin Tube Vaporizers

Heat from the air is transferred through natural convection to the vaporizer pipe. The natural convection is created by the temperature difference between the atmospheric air and the air around the cold pipe.

Heat is conducted from the outside of the pipe to the inner wall. Heat is transferred through forced convection from the inner wall to the product. The forced convection is created by the fluid flow in the pipe.

Fan Assisted Vaporizers

Fan assisted vaporizers are ambient vaporizers that use a fan to increase the efficiency of the vaporizer. Unlike standard ambient vaporizers, the finned tubes are installed within a framework and are enclosed by walls on all sides. The top normally consists of fan housing with side openings to draw in air. The bottom is kept open. An electric fan in the top of the frame provides forced draught downward over the tubes. Forced convection is more efficient than natural convection; therefore fan assisted vaporizers have better efficiency.


Manufacturer ISISAN
Equipment Name Atmospheric Vaporizer
Type Vertical/Horizontal
Operating Inlet Temperature (°C) -196° C / +65° C
Operating Outlet Temperature (°C) 20 °C below Ambient
Relative Humidity (%) 90%
Operating Inlet Pressure (BAR) 25 BAR to 60 BAR
Design pressure (BAR) Operating Inlet Pressure
Pneumatic Test Pressure (BAR) 1.1 times of Operating Pressure
Hydro test (BAR) 1.5 times of Operating Pressure
Manufacturing Code ASME SEC VIII DIV 1
Pressure Drop 0.9 BAR
Tube I.D. (mm) 21.5
Number of Fins Per Tube 8
Extrusion Diameter 6''
Extrusion Spacing 312mm
Materials of Construction Aluminum 6063-T5
Model Number ISISAN-500 ISISAN-1000 ISISAN-1500 ISISAN-2000 ISISAN-2500
Capacity 500 NM3/Hr 1000 NM3/Hr 1500 NM3/Hr 2000 NM3/Hr 2500 NM3/Hr
Effective Surface Area per Unit Approximate (M2) 137M2 274M2 412M2 548M2 685M2
End of Connection INLET 3/4" UNION 11/2" UNION 11/2" UNION 11/2" UNION 11/2" UNION
CAPACITY 100 Nm3 / hr 500 Nm3 / hr 2500 Nm3 / hr 5000 Nm3 / hr
Type Vertical / Horizontal
Operating Temp -196°C + 50°C
Operating Outlet Temp 20°C Below Ambient
Relative Humidity 90%
Design Pressure 100 Bar
MAWP 100 Bar
Hydro Test Pressure 150 Bar
Manufacturing Code ASME SEC VIII DIV 1
Pressure Drop 1 Bar
Tube ID IN MIM 12.5 / 15/ 21
Inlet & Outlet Connection 3/4" NPT (F) 1" Flange 1.5/3" Flange 1.5/3" Flange


1.) All material of construction will be aluminium with SS 304 Pipes. ASME SEC VIII DIV ! latest edition.

2.) We design & manufacture vaporizers up to 450 bars at, any capacity as per customer requirements.