Abstract: In some aspects, methods for limiting damage to a plasma arc torch body resulting from a consumable failure within the torch can include determining a specified conductivity parameter set point of a current to be provided to the plasma arc torch for a material processing operation; measuring a detected conductivity parameter of plasma arc current being provided to the plasma torch to perform the material processing operation; comparing the specified conductivity parameter set point to the detected conductivity parameter of plasma arc current and calculating an error term signal; and based on a determination that the error term signal exceeds a threshold amount, initiating a plasma arc shut down sequence to extinguish the plasma arc to limit damage to the plasma arc torch body.

Abstract: A coolant tube for a plasma arc torch is provided. The coolant tube includes an elongated coolant tube body including a distal portion configured to engage an electrode and a proximal portion configured to engage a body of the plasma arc torch. The coolant tube also includes a first electrically conductive element coupled to the distal portion of the elongated coolant tube body. The first electrically conductive element is configured to physically contact an electrode. The coolant tube further includes a second electrically conductive element coupled to the proximal portion of the elongated coolant tube body. The second electrically conductive element is configured to physically contact the body of the plasma arc torch. The elongated coolant tube body defines a current path and a fluid path between the body of the plasma arc torch and the electrode.

Abstract: In some aspects, nozzles for a plasma arc torch can include a first body having a first end, a second end, and a longitudinal axis; and a second body disposed about a portion of the first body to complement the first body, the second body defining a set of channels formed on an internal surface shaped to form a set of liquid flow passages between the first body and the second body, the second body at least partially defining at least one inlet and at least one outlet to the set of liquid flow passages.

Abstract: A coolant tube for a plasma arc torch is provided. The coolant tube includes an elongated coolant tube body including a distal portion configured to engage an electrode and a proximal portion configured to engage a body of the plasma arc torch. The coolant tube also includes a first electrically conductive element coupled to the distal portion of the elongated coolant tube body. The first electrically conductive element is configured to physically contact an electrode. The coolant tube further includes a second electrically conductive element coupled to the proximal portion of the elongated coolant tube body. The second electrically conductive element is configured to physically contact the body of the plasma arc torch. The elongated coolant tube body defines a current path and a fluid path between the body of the plasma arc torch and the electrode.

Abstract: In some aspects, methods for limiting damage to a plasma arc torch body resulting from a consumable failure within the torch can include determining a specified conductivity parameter set point of a current to be provided to the plasma arc torch for a material processing operation; measuring a detected conductivity parameter of plasma arc current being provided to the plasma torch to perform the material processing operation; comparing the specified conductivity parameter set point to the detected conductivity parameter of plasma arc current and calculating an error term signal; and based on a determination that the error term signal exceeds a threshold amount, initiating a plasma arc shut down sequence to extinguish the plasma arc to limit damage to the plasma arc torch body.

Abstract: In some aspects, nozzles for a plasma arc torch can include a first body having a first end, a second end, and a longitudinal axis; and a second body disposed about a portion of the first body to complement the first body, the second body defining a set of channels formed on an internal surface shaped to form a set of liquid flow passages between the first body and the second body, the second body at least partially defining at least one inlet and at least one outlet to the set of liquid flow passages.

Abstract: An apparatus for protecting plants is includes a covering that has a means for opening and closing the covering, an element that may be for heating or cooling and is releaseably attached to the protective covering and a means for securing the covering around the plant.

Abstract: A signaling device for a water-skiing tow boat that displays a warning flag in the event of a fallen skier. The device can be attached to a boat hull or other structure and includes an electro-mechanical actuator operated by a local or remotely controlled switch or sensor to retract or extend the warning flag in or out of a weatherproof housing. To further enhance skier safety, an indicator light is used to attract attention in bright daylight as well as under low light conditions. The device can be operated by a radio-frequency link to remotely control the flag from any location around the tow boat and can be powered by the electrical system of the towing boat or by a rechargeable battery pack.