公开(公告)号：WO1993013905A1

公开(公告)日：1993-07-22

申请号：PCT/US1992003924

申请日：1992-05-08

Applicant: HYPERTHERM, INC.

Inventor： HYPERTHERM, INC. ,  COUCH, Richard, W. ,  SANDERS, Nicholas, A. ,  LUO, Lifeng ,  SOBR, John ,  BÄCKANDER, Patrik

IPC: B23K09/00

CPC classification number: H05H1/34 ,  H05H2001/3421 ,  H05H2001/3436 ,  H05H2001/3442 ,  H05H2001/3457 ,  H05H2001/3468

Abstract: In a plasma arc cutting torch (10), a flow of plasma gas is bypassed out of a plasma chamber (14) preferably at an annular gap between a pre-orifice in an inner nozzle piece (36) and an exit nozzle orifice in an outer nozzle piece (38). A bypass channel (20) formed between the inner and outer nozzle pieces directs the bypass flow to atmosphere. A metering valve (22) or restricting orifice remote from the gap controls the amount of the bypass flow and delays the response of changes in the flow parameters in the plasma chamber (14) to changes in the bypass flow. The pre-orifice and nozzle orifice are positioned and dimensioned to optimize the mass flow velocity and the strength of a vortex-type flow at the pre-orifice, thereby creating a virtual nozzle immediately below the electrode (30). The gas flow in the plasma chamber (14) is highly uniform and very steady.

公开(公告)号：WO1993023193A1

公开(公告)日：1993-11-25

申请号：PCT/US1993004077

申请日：1993-04-30

Applicant: HYPERTHERM, INC.

Inventor： HYPERTHERM, INC. ,  COUCH, Richard, W. ,  SANDERS, Nicholas, A. ,  LUO, Lifeng ,  LU, Zhipeng ,  BÄCKANDER, Patrik ,  SOBR, John

IPC: B23K09/00

CPC classification number: H05H1/34 ,  H05H2001/3442 ,  H05H2001/3452

Abstract: The diameter of a hafnium insert (44) press fit into the bottom end of a copper electrode (42) varies as a function of the level of a current carried by the electrode. The diameter is the minimum necessary to support emission at that current level while also protecting the copper body against attack by the arc. The insert (44) is generally circular and preferably extends completely through the bottom wall (42g) to a circulating flow of cooling water at a hollow interior (48) of the electrode. The bottom wall includes an annular recess (42d) in a portion of the copper wall surrounding the insert. A coolant tube (56) extends into the recess in a spaced relationship to provide a high flow velocity of the coolant over the interior rear surface of the electrode.