초록 ▼

A crosshead for extruding an annular layer of thermoplastic material about a central longitudinal axis. The crosshead comprises a die having an annular slotted die opening surrounding the axis, a transverse inlet passageway for receiving molten thermoplastic material, an annular cavity connected to

A crosshead for extruding an annular layer of thermoplastic material about a central longitudinal axis. The crosshead comprises a die having an annular slotted die opening surrounding the axis, a transverse inlet passageway for receiving molten thermoplastic material, an annular cavity connected to the inlet passageway, an annular distribution passage connected to the annular cavity and an annular connecting passage extending from the annular distribution passage to the die opening. The annular cavity and annular distribution passage each extend radially with respect to the longitudinal axis. Two or more layers of thermoplastic material are extruded by the crosshead when it is equipped with two or more dies.

대표청구항 ▼

A crosshead including a die for extruding an annular layer of thermoplastic material about a central longitudinal axis comprising: (a) an annular slotted die opening surrounding said longitudinal axis; (b) an inlet passageway spaced from said longitudinal axis and located at one side of said crosshe

A crosshead including a die for extruding an annular layer of thermoplastic material about a central longitudinal axis comprising: (a) an annular slotted die opening surrounding said longitudinal axis; (b) an inlet passageway spaced from said longitudinal axis and located at one side of said crosshead for receiving molten thermoplastic material, said inlet passageway having a flow axis which is generally transverse to said longitudinal axis; (c) an annular cavity located between said axis and the inlet passageway, and connected to the inlet passageway, said cavity surrounding said longitudinal axis and extending radially of said longitudinal axis, the cross-sectional area of said cavity gradually diminishing along each half of its circumference from the inlet passageway to a point on its circumference opposite the inlet passageway; (d) an annular distribution passage located between said longitudinal axis and said annular cavity and connected to said annular cavity, said distribution passage surrounding said longitudinal axis and extending radially of said annular distribution axis, the depth of said longitudinal passage being substantially less than the depth of the annular cavity and the cross-sectional area of said distribution passage gradually diminishing along each half of its circumference from the inlet passageway to a point on its circumference opposite the inlet passageway; and (e) an annular connecting passage surrounding said longitudinal axis and extending from the distribution passage to the die opening.