A plasma processing device includes: a chamber; a flat-plate-shaped first electrode; a first high frequency power supply; a helical second electrode disposed outside the chamber and disposed to face the first electrode with a quartz plate forming an upper lid of the chamber therebetween; and a gas introducing unit, in which a second high frequency power supply and a third high frequency power supply are configured to be electrically connected to the second electrode, the second high frequency power supply being configured to apply an AC voltage of a second frequency to the second electrode, the third high frequency power supply being configured to apply an AC voltage of a third frequency to the second electrode, and the third frequency being higher than the second frequency; and two types of AC voltages are configured to be simultaneously applied.

A plasma processing device includes: a chamber; a flat-plate-shaped first electrode; a first high frequency power supply; a helical second electrode disposed outside the chamber and disposed to face the first electrode with a quartz plate forming an upper lid of the chamber therebetween; and a gas introducing unit, in which a second high frequency power supply and a third high frequency power supply are configured to be electrically connected to the second electrode, the second high frequency power supply being configured to apply an AC voltage of a second frequency to the second electrode, the third high frequency power supply being configured to apply an AC voltage of a third frequency to the second electrode, and the third frequency being higher than the second frequency; and two types of AC voltages are configured to be simultaneously applied.

A swirl ring for a plasma arc torch includes a body configured to at least partially surround and slidingly engage an electrode of the plasma arc torch. The body includes a first end and a second end opposite the first end, the first and second ends defining a longitudinal axis, and at least one protuberance extending from the second end in a direction of the longitudinal axis. The at least one protuberance is configured to engage a switch of the plasma arc torch for sensing a presence of a swirl ring in the plasma arc torch.

A swirl ring for a plasma arc torch includes a body configured to at least partially surround and slidingly engage an electrode of the plasma arc torch. The body includes a first end and a second end opposite the first end, the first and second ends defining a longitudinal axis, and at least one protuberance extending from the second end in a direction of the longitudinal axis. The at least one protuberance is configured to engage a switch of the plasma arc torch for sensing a presence of a swirl ring in the plasma arc torch.

A liquid coolant tube for a plasma arc cutting torch including a hollow elongated inner body shaped to translate within a hollow elongated outer body. The hollow elongated outer body of the liquid coolant tube is shaped to fixedly connect to the plasma arc cutting torch and includes a set of electrode guides. An external surface of the hollow elongated outer body and the set of electrode guides partially define a set of coolant flow channels between the set of electrode guides. The set of electrode guides are shaped to facilitate alignment of an electrode within the plasma arc cutting torch.

A liquid coolant tube for a plasma arc cutting torch including a hollow elongated inner body shaped to translate within a hollow elongated outer body. The hollow elongated outer body of the liquid coolant tube is shaped to fixedly connect to the plasma arc cutting torch and includes a set of electrode guides. An external surface of the hollow elongated outer body and the set of electrode guides partially define a set of coolant flow channels between the set of electrode guides. The set of electrode guides are shaped to facilitate alignment of an electrode within the plasma arc cutting torch.

A liquid cooled shield assembly for a plasma arc torch includes an inner cap and a shield. The inner cap includes a substantially hollow body having a proximal end and a distal end that define a longitudinal axis, the distal end including an annular portion about the longitudinal axis. The inner cap also includes a liquid passage defined, at least in part, by an interior surface of the body, the liquid passage including a first set of ports in the annular portion, the first set of ports extending between an interior portion of the body and an exterior portion of the body to convey a liquid therethrough. The shield at least partially surrounds the inner cap and has a liquid impingement region on an interior surface of the shield adjacent to the first set of ports, the liquid impingement region for receiving the cooling liquid.

A liquid cooled shield assembly for a plasma arc torch includes an inner cap and a shield. The inner cap includes a substantially hollow body having a proximal end and a distal end that define a longitudinal axis, the distal end including an annular portion about the longitudinal axis. The inner cap also includes a liquid passage defined, at least in part, by an interior surface of the body, the liquid passage including a first set of ports in the annular portion, the first set of ports extending between an interior portion of the body and an exterior portion of the body to convey a liquid therethrough. The shield at least partially surrounds the inner cap and has a liquid impingement region on an interior surface of the shield adjacent to the first set of ports, the liquid impingement region for receiving the cooling liquid.

An electrode-supporting assembly for a contact-start plasma arc torch has an insulator that partially houses an electrode, and employs a spring-loaded plunger to bias the electrode to a forward position. The spring is engaged between the plunger and a contact element attached to the insulator, and may conduct electrical current to the electrode. The plunger, spring, and contact element are retained in the insulator when the torch is opened to replace the electrode, which is a consumable part. The electrode and the plunger have axially-engagable mating surfaces to assure good thermal and electrical conductivity therebetween. Conductivity can be further enhanced by forming the plunger of silver or a silver-bearing alloy. In some embodiments, a passage through the insulator is partitioned into forward and rear chambers, with the plunger, spring, and contact element trapped in the rear chamber.

An electrode-supporting assembly for a contact-start plasma arc torch has an insulator that partially houses an electrode, and employs a spring-loaded plunger to bias the electrode to a forward position. The spring is engaged between the plunger and a contact element attached to the insulator, and may conduct electrical current to the electrode. The plunger, spring, and contact element are retained in the insulator when the torch is opened to replace the electrode, which is a consumable part. The electrode and the plunger have axially-engagable mating surfaces to assure good thermal and electrical conductivity therebetween. Conductivity can be further enhanced by forming the plunger of silver or a silver-bearing alloy. In some embodiments, a passage through the insulator is partitioned into forward and rear chambers, with the plunger, spring, and contact element trapped in the rear chamber.