Demaco gas vent products: automatic gas vent and degasser

It’s all about Cryogenius.


When a cryogenic application is temporarily at a standstill, some gas formation takes place due to heat-in-leak. As a result of heat-in-leak and a low flow, some of the liquid gas evaporates, which hinders the flow in the system. When the application is subsequently switched on again, any gas bubbles that have formed must first leave the system before pure liquid gas can reach the application. This results in some waiting time when switching on the application or having to discharge hot gas through a cold product.

Our automatic gas vent and degasser make use of the fact that gas is lighter than liquid. By placing one of these products in a cryogenic infrastructure, the gas formed within this system is released into the atmosphere. As a result, the system itself remains filled with liquid gas and is always immediately available at the offtake points.

Demaco supplies its customers with both automatic gas vents and degasers:

Automatic gas vents

By installing a gas vent at a strategic location (often the highest point) of a cryogenic infrastructure, the gas bubbles are discharged from the system when there is zero or very little demand.

How an automatic gas vent works:

The degasser

The degasser has the same purpose as the automatic gas vent and can be placed in different places in the infrastructure.

The significant difference between an automatic gas vent and a degasser is that a degasser also works during operation whereas a gas vent only works when there is zero or very little demand. Also, degassers generally release more gas than automatic gas vents.

The degasser brings the flowing liquid gas to a temporary halt in a small vessel; this allows the gas bubbles in the vessel to float to the surface. These bubbles are then released through a so called ‘floater’, after which the high quality liquid gas continues to flow through the pipes towards the application.


Both our automatic gas vents and degassers are available in various configurations, and both are vacuum insulated. Furthermore, both products are entirely mechanical built; hence, electrical power or compressed air is not required.

As is the case with all our products, our automatic gas vents and degassers are entirely modular in design. They come in different sizes and are suited for a pressure rate up to PN16 when used with liquid nitrogen and up to PN28 when used with liquid CO2.

For more specifications, download the product sheets of our Automatic gas vent and Degasser.

Application fields of automatic gas vents and degassers

Automatic gas vents and degassers are mainly used in industries where immediate access to pure liquid gas is required after any downtime, for example, filling stations in hospitals or laboratories or refrigeration equipment in the food or automotive industry.

Our degassing products are widely used to improve response to demand times or to enhance the liquid nitrogen quality. However, using them for other cryogenic gases is also possible, be it to a limited extent.


Our degasser and automatic gas vents are elements of our extensive cryogenic construction modules. Depending on the customer’s requirements, we supply degassers and automatic gas vents as modular parts of a cryogenic system. For example, mounted into an infrastructure of vacuum insulated transfer lines, complete with vacuum insulated valves, solenoid valves, and Johnston or welding couplings and degasser heaters.

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