Exchanging the process gas source

NOTICE

notice

Penetration of ambient air into the system

Each time you change the cylinder, ambient air gets into the connecting parts of the system. To prevent the gas and the entire system from being contaminated, the connection must be purged before gas is drawn from the cylinder again. In the case of non-toxic, non-corrosive gases, this can be done by means of multiple pressure purges with process gas. In the case of corrosive or toxic gases or gases that are hazardous in some other way, purging must be carried out with inert gas.

WARNING

warning

Gas source exchange

If a gas source exchange is performed incorrectly, gas leakage and poisoning of persons may occur.

  1. The gas source exchange are to be carried out by trained specialist personnel and never unattended.
  2. A pressure test must be conducted after each gas source exchange.
  3. For each gas source exchange, a new seal suitable for the used gas is to be used.
  4. Wear the personal protective equipment prescribed in the risk assessment.

With each gas source exchange, check the port for leak-tightness. We strongly recommend replacing the seal every time the gas source is exchanged. Always turn the shut-off valves slowly and as far as the stop when opening or closing them!

Changing the supply side

  1. The position of the lever indicates which side the gas is drawn from:
    Switching lever up – gas is drawn from the gas source on the left-hand side: The outlet pressure of the pressure regulator on the left is set higher than that of the pressure regulator on the right.
    Switching lever down – gas is drawn from the gas source on the right-hand side:
    The outlet pressure of the pressure regulator on the right is set higher than that of the pressure regulator on the left.
    Middle position - If the handle is positioned horizontally, the two pressure regulators are set to the same outlet pressure.
  2. The gas source pressure on the preselected side falls below the outlet pressure of the reserve side: the reserve side takes over the job of supplying process gas to the connected consumers without interruption.
    With single-stage switching panels, the outlet pressure falls markedly when there is an automatic switch from the preselected operational side to the reserve side. When the switching lever is operated, the reserve side is raised to the normal outlet pressure level and thus becomes the operational side. Two-stage switching panels keep the pressure very largely constant.
  3. Move the switching lever to increase the outlet pressure again on the reserve side that has now become the operational side.
  4. Change the gas source on the side that has now become the reserve side.

 

Removing the empty process gas source:

  1. Close the process gas source valve.
  2. Close valve HPI.
  3. Open valve HPV to reduce the pressure.
  4. Close valve HPV.
  5. Disconnect the process gas source connection.
  6. Mount the sealing nut on the gas source valve and protective cap on the process gas source.
  7. Identify, secure and remove the empty process gas source.

 

Connecting the new process gas source:

  1. Provide new process gas source, position in front of the bracket and secure using the safety chain.
  2. Remove and retain the protective cap and screw plug.
  3. Check the port thread and sealing; a new sealing must be used each time the gas source is exchanged.
  4. Screw the process gas connection onto the gas source valve by hand and tighten it gastight with a spanner.
  5. Open the process gas source valve, build up pressure, and close it again. Check using leak test spray whether the process gas port is leak-tight.
  6. Open valve HPV to reduce the pressure.
  7. Close valve HPV.
  8. Open the process gas source valve to build up the pressure with purge gas (process gas).
  9. Wait until the pressure has been built up and close the process gas source valve again.
  10. Open valve HPV to build up the pressure and then close it again.
    Repeat steps 8 to 10 depending on the gas type at least 10 times.
  11. Open the gas source valve to fill the gas connection with process gas.
  12. Close the process gas source valve.
  13. Open valve HPI. In the case of two-sided pressure control panels with manual switchover, keep the HPI valve closed, and do not open it until the supply side has to be changed again.
  14. Slowly open the gas source valve.

 

The pressure control panel is ready for supply.