| 摘要 |
1,235,539. Extruding. ALLMANNA SVENSKA ELEKTRISKA A.B. 31 Oct., 1968 [1 Nov., 1967], No. 51682/68. Heading B3P. An hydrostatic extrusion press comprises a main operating cylinder 2 with a pressuregenerating piston 3 whose rod 5 extends into a high-pressure chamber 25 and a sealing pressure ring 16 which is urged against the end of the high-pressure chamber with a force dependent on the pressure in the chamber. The ring is mounted on a set of piston-rods 15 of either a set of separate pistons 14 in cylinders 13 in the piston 3 of the main cylinder 2 or of an annular piston in an annular cylinder in the piston 3. The individual cylinders 13 are interconnected by ducts 19, 21 and the upper spaces 18 of the cylinders 13 are connected to the upper space 6 of the main cylinder. The lower spacers 7, 20 are connected by a common line 9 to a pressure source or a reservoir. Initially a valve 10 directs fluid only to the upper spaces 18 of the cylinders 13 to lower the ring 16. After abutment the pressure rises in the spaces 18 and a pressure gauge 35 sends an impulse to the valve 10 to move it to a central position. The spaces 6, 18 are thus interconnected through an adjustable reduction valve 23. Thus the pressure in the space 18 which determines the pressure of the ring 16 against the chamber 25 is proportional to the pressure in the space 6 which is in turn related to the pressure in the high-pressure chamber. |
