Gas Line

September 8, 2013 at 8:48 pm

The gas line is basically the fuel supply line for the Fusor. It provides the deuterium atoms which fuse in the vacuum chamber in the form of deuterium gas. The equipment needed for the gas line is listed below.

 Required pieces:

– A tank or lecture bottle of deuterium

– A hydrogen regulator

– A gas needle valve

– A capillary tube (flow restrictor)

– Copper or stainless steel piping.

Optional pieces:

– Dryer

-A micron filter

– Mass flow controller

Gas line design

Gas line design

Gas line equipment – Technical specs


Deuterium Gas (approximate cost €200-500): This will be obtained from BOC Industrial Gases Ireland, the main supplier of deuterium in Ireland. The smallest cylinder that they supply will be sufficient. It is simply 2H2  gas in a pressurised lecture bottle or tank. As I mentioned before, deuterium is literally the fuel of the Fusor. As long as the gas is at 99% purity it is usable. The gas will be used strictly in accordance with BOC safety regulations.


Hydrogen regulator (approximate cost €40-100): A hydrogen regulator is needed to reduce the pressure of the deuterium (isotope of basic hydrogen) as it exits from the cylinder into the gas line so it is safe and non- combustible. A two-stage hydrogen regulator is preferable, but a single-stage can be used. Any regulator used needs to have a maximum input of 2,000 psi.


Gas needle valve (approximate cost €30-100): A needle valve is used as the main control and shut-off valve in the gas line. It is used to precisely control and monitor the flow of deuterium gas into the Fusor chamber. Any precision needle valve can be used, the higher the precision, the better, the choices range from a hyper-fine Swagelock needle valve to a micrometer, bellows sealed, VCR valve.


Capillary tube/restrictor line (approximate cost €20-40): A capillary tube or restriction line is used to provide a final regulation on the amount of deuterium reaching the vacuum chamber and an extra level of control over the entry of deuterium into the Fusor. A capillary tube is typically a long line of soft, coiled, stainless steel, hypodermic needle tubing with a hole only 1-2mm in diameter.


Piping (approximate cost €50-150): Copper or stainless steel (grade 306+) piping is used along with fittings, the piping is usually 6 mm or 3 mm in diameter and fittings can range from professional, stainless steel VCR fittings to brass Swagelok ones.


Dryer (optional extra, approximate cost €20-120): This is an optional part of the gas line. The purpose of a dryer is to dry any impurities out of the deuterium gas.  If the gas is obtained through electrolysis of deuterium oxide, it is nearly always already dried before being stored in a cylinder. Any dryer is suitable, as is a cold trap or any other type of device used to clean wet gases.


Micron filter (optional extra, approximate cost €100-200): Another optional part of the gas line. Like the dryer, a micron filter is used to help maintain purity of the gas. A micron filter typically filters out all solids and nearly any liquid.


Mass flow controller (optional extra, approximate cost €100-400): Mass flow controllers provide an extremely accurate control over the gas flow into the vacuum chamber and are quite useful in the Fusor.  Any mass controller used needs to be able to supply at least 1 SCCM (standard cubic centimetres per minute – unit of mass flow rate).