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Re: Oxy-Acetylene Welding Regulator Safety

Originally Posted by Serius

I am new to welding and had a few safety questions. I have only started with Oxy-Acetylene basics.

In my book it says to not open the tank valves too quickly because this can cause damage to the regulator. Can it cause damage even when the T-valve is uncompressed (it would read at 0 psi with an uncompressed T-valve even with the tank open)?

At my station, I unintentionally let the acetylene go from 5 psi to 20 psi by re-opening the tank valve after closing it. Then I immediately turned the acetylene valve off, the bled the line. Could I possibly have damaged my regulator by doing this? I read that acetylene is unstable at above 25 psi and can self-ignite from it's own heat under pressure. Could excess heat and pressure have damaged the regulator? Thanks.

Opening a cylinder valve with the adjust screw turned-in can damage the HP valve seat. With most single stage regulators used today, if the adjusting screw is backed all the way out the HP valve seat will be closed. With the HP valve closed there is no way to damage the regulator. However, not all regulators are same. Here are few instance that opening a cylinder valve to fast can damage your unit.

1- Older single stage regulators used a Yolk design. In most of today's regulators, HP gas helps to close the HP valve seat. The older yolk design regulators, the HP is used to open the HP valve. If you open a cylinder valve too quickly on an older yolk designed regulator you can get cylinder pressure on the low side of the system.
2- Two stage regulators-Two stage regulators have two adjusting screws. One is preset and therefore, when there is no HP gas the HP valve on the first stage is open. Opening a cylinder to quickly can damage the first stage HP valve seat.
3-Flowmeters- Opening a cylinder valve to fast with a flowmeter can damage the unit. Both piston and diaphragm style flowmeters have the valve seat open when there is no HP gas coming in to the unit.
4- Even on today's single stage regulators with the adjusting screw back all the way out, the HP surge from opening the valve to quickly can rupture a HP gauge.

Therefore, it is best to be in the habit of open the cylinder valves slowly.

As to your regulator climb to 20 psi, that indicates the regulators HP valve seat has failed. If it continues to climb when the cylinder valve is open, you will want to have it rebuilt.

Re: Oxy-Acetylene Welding Regulator Safety

Can't answer your question, but I would avoid acetylene above 15 psi. Many regulators have a red line at 15 psi, and some won't even let you go much above that.

Re: Oxy-Acetylene Welding Regulator Safety

Correct you should not open the valves too quickly. As far as damaging the diaphragms even with the T handle loosened, I believe it may possibly. As far as the 5 to 20 issue, I would think that nothing detrimental happened to the Regulator.
The Regulator Doctor will probably chime in here in the next day or two to add anymore insight as he is the "Go To" guy on this subject.

Oxy-Acetylene Welding Regulator Safety

I am new to welding and had a few safety questions. I have only started with Oxy-Acetylene basics.

In my book it says to not open the tank valves too quickly because this can cause damage to the regulator. Can it cause damage even when the T-valve is uncompressed (it would read at 0 psi with an uncompressed T-valve even with the tank open)?

At my station, I unintentionally let the acetylene go from 5 psi to 20 psi by re-opening the tank valve after closing it. Then I immediately turned the acetylene valve off, the bled the line. Could I possibly have damaged my regulator by doing this? I read that acetylene is unstable at above 25 psi and can self-ignite from it's own heat under pressure. Could excess heat and pressure have damaged the regulator? Thanks.