Thermal Torch Lead Gas Delivery Methods and Related Systems and Devices

A plasma cutting system comprising:

• a power supply;
• a torch;
• a plasma gas supply lead line extending from a gas supply to the torch and comprising a first segment proximate to the power supply and a second segment proximate to the torch;
• and
• an in-line valve positioned in the lead line between the first segment and the second segment,
• a controller programmable to control a position of the in-line valve, such that the in-line valve is selectively closable by the controller to (a) capture a static volume of gas in the first segment and (b) establish a decayable volume of gas in the second segment.

A method for operating a plasma torch system, the plasma torch system including a plasma power supply coupled to a torch by a lead line, an in-line valve located in the lead line and a section of the lead line between the in-line valve and the torch defining an off-valve hose segment, the method comprising:

• supplying a gas to the torch through the lead line;
• selectively closing the in-line valve to establish a decayable volume of gas in the off-valve hose segment;
• and
• initiating a plasma arc in the torch when a pressure of the gas at the torch reaches a pressure value within a predetermined range by:
• enabling a pressure of a volume of gas captured between the in-line valve and the torch to dissipate to the pressure value;
• or
• opening the in-line valve to release a volume of gas trapped between an upstream regulator valve and the in-line valve, and enabling a pressure of the gas in the off-valve segment to increase to the pressure value.

A method for initiating a plasma arc in a plasma arc torch, the method comprising:

• flowing a plasma gas to the plasma arc torch through a plasma gas supply line and an in-line valve within the plasma gas supply line in a first position, thereby generating a first pressure in a segment of the plasma gas supply line between the in-line valve and the plasma arc torch;
• changing the in-line valve to a second position to adjust the flow of the plasma gas to the plasma arc torch and generating a second pressure that varies over time in the segment between the in-line valve and the plasma arc torch;
• and
• initiating a plasma arc when the varying second pressure reaches a pressure value within a predetermined range.

A method for initiating a plasma torch system including a plasma power supply coupled to a torch by a lead line, an in-line valve located in the lead line, and a section of the lead line between the in-line valve and the torch defining an off-valve hose segment, the method comprising:

• supplying a gas to the torch through the lead line;
• closing the in-line valve to establish a decayable volume of gas in the off-valve hose segment;
• and
• initiating a plasma arc in the torch while the in-line valve is closed.