Abstract: A marine propulsion water jet system which operates at high efficiency and automatically adjusts itself to maintain a relatively constant primary injection water velocity over a wide speed range. The propulsion system includes a fluid flow amplifier by which a high velocity principal water flow is injected into a slower velocity secondary water flow to form a water jet. The fluid flow amplifier includes an adjustable orifice through which the principal water flow is injected into the secondary water flow and the size of the orifice is automatically adjusted in order to maintain a relatively constant water jet velocity.

Abstract: A molten metal treatment apparatus comprising a passage of predetermined size and length for receiving superheated molten metal from a source thereof, and for supplying the molten metal for subsequent casting; a gas inlet and a control valve for controlling the velocity of the molten metal through the passage by exposing the molten metal to a source of pressurized gas; a cooling jacket at least partially surrounding the passage for controlling the temperature of the molten metal within the passage between predetermined upper and lower limits for forming a thin solidified shell having a molten metal core within the passage; the combination of the velocity of molten metal and the temperature of the molten metal within the passage for allowing dendrites to grow into the molten core from the solidified shell, and for breaking off portions of the dendrites and entraining them in the molten metal thereby producing a solids content within the molten metal for subsequent casting.

Abstract: Strain reduction or reversal technique for continuous casting of a metal billet element wherein there is provided an axial mold wall which is oscillatable, a plug element in the axial wall which may be solid in the sense that it closes one end of the mold or which may be of a type in which molten metal may flow therethrough into the mold, one of said elements being oscillatable with respect to the axial wall in a manner to relieve strain on metal newly freezing to the axial wall during oscillation of the axial wall.

Abstract: Method and apparatus for casting a metal article in a mold at least as long as the article, utilizing a cooled mold of elongated form having top and bottom portions. The method includes the steps of introducing molten metal from a source through the bottom portion of the mold, flowing molten metal into the mold so as to form a solidifying casting shell which during casting occupies at least 40% of the cross-sectional mold area and has a molten core, and flowing molten metal from the source through the core towards the mold top.

Abstract: Method and apparatus for continuously casting metal tubing, utilizing an oscillatable mold, which lends itself to the casting of tubing of relatively large internal diameter. Molten metal is poured directly into the mold having a chilled axial wall structure, and then a starting bar, having at least an annular end portion immersed in the molten metal in the mold, is moved relatively to the mold to withdraw the solidifying cast metal tubing adhering thereto, during oscillation of the mold, the molten metal for such tubing being supplied from the mold. The supply of molten metal in the mold may be replenished by pouring additional molten metal directly into the mold through the annular starting bar without contact of the molten metal with either the starting bar or the solidifying tubing prior to the entry of such molten metal into the mold.

Abstract: Method and apparatus for casting a metal article in a mold at least as long as the article, utilizing a cooled mold of elongated form having top and bottom portions. The method includes the steps of introducing molten metal from a source through the bottom portion of the mold, flowing molten metal into the mold so as to form a solidifying casting shell which .Iadd.a .Iaddend.during casting occupies at least 40% of the cross-sectional mold area and .Iadd.a .Iaddend.has a molten core, and flowing molten metal from the source through the core towards the mold top .Iadd.at a filling rate, dependent on the mold cross sectional area, such that the product produced will have a relatively fine grained structure throughout the cross-section thereof.Iaddend..