Gas Feed Systems

Pressure reducing valve with assembled flow meter

Protective Gases

Protective gases are used to force oxygen out of the gas feed boxes mentioned above. Make sure to use protective gases behaving neutrally toward the heat treated part. The protective gases should be inert, meaning no chemical bonding should occur with the workpiece and no reactions should be enduced. In many cases, nitrogen is used as protective gas. Our experience shows that nitrogen does not always lead to sufficient results. A longer preflush time must also be used. Better results are achieved by adding a mixture of nitrogen and adding some hydrogen. Hydrogen acts as a reducing constituent and reacts with the oxygen. This gas mixture is known as forming gas and available in stores. Experience has shown that adding 5 % hydrogen leads to good results. According to the EU material safety data sheet this mixture is considered as not flammable. National regulations, however, must be observed. This gas can be obtained in premixed form. No measures must be taken in advance to prevent explosions. If the workpiece has an affinity to hydrogen, argon used as protective gas can lead to good results. Nitrogen and argon are gases which are heavier than air. This makes it relatively easy to fill the protective gas containers. Forming gas with added hydrogen is lighter, but it has the advantage of burning at higher temperatures and therefore binds with the oxygen. Even in a cold state, the leaking hydrogen transports the oxygen very easily out of the container. Always make sure that the room is properly ventilated when working with protective gases. Country-specific safety regulations must also be followed.

Manual Gas Feed Fitting for Bottles

  • Pressure reducing valve with assembled flow meter and attached pressure gauge indicating the bottle pressure The assembled variable area flow meter ensures good readability of the amount used
  • Connection: screw connection for bottle
  • Exit: 3/8 inch hose connection
  • 200 bar intake pressure, 4 bar outlet pressure
  • Incl. 4 m 3/8 inch connecting hose
For N 7 - N 17/HR
 For N 21 - N 641/13, N 30/45HA + N 500/85HA
Article no.Type of gasFlow rate Article no.Type of gasFlow rate
  l/min   l/min
631000306Ar0 - 16 631000309Ar0 - 32
631000307N20 - 16 631000310N20 - 32
631000308Forming gas 95/50 - 16 631000311Forming gas 95/50 - 32
*Article no. for Spain, France and Portugal on request