| 摘要 |
1,162,067. Fluid-pressure servomotor systems. ATLAS COPCO A. B. June 8, 1967 [June 23, 1966], No. 26481/67. Heading G3P. A two-stage screw-action compressor 2, 3 has a throttle valve 6 in the intake duct 4 and an unloading valve 22 in a vent line 17 connected to the delivery line 12. Valves 6, 22 are biased by spring 33 to the positions shown. On starting the compressor, a vacuum is created in duct 5 and acts, via restricted line 30, line 31 and pilot valve chambers 34, 36, in chambers 28, 29 of rolling diaphragm motor 26. To load the compressor, a spool 66 is depressed to admit oil under pressure to line 46 to lift diaphragm 48 to reposition valve 37, to seat head 38 and unseat head 39. The vacuum in line 8 has moved flap 54 to the position shown and inlet pressure in duct 4 now acts via chamber 53 and lines 51, 70 in chamber 29 to move the valve 6 to an open position and the valve 22 to a closed position. Oil pressure in line 68 maintains the spool 66 in its depressed position. Flap 54 is now moved by the interstage pressure in line 8 to seat at 57 and admit this pressure to chamber 29 to maintain valve 6 open and valve 22 closed. When the pressure in receiver 14 reaches the desired level, valve 72 admits this pressure to chamber 74 to return valve 37 to the position shown. The pressure across diaphragm 26 is thereby equalized and the valves 6, 22 are returned to the unloading positions shown. Line 58 may alternately connect with the outlet duct 12. In the modification Fig. 2 (not shown), valve 60 is replaced by a solenoid operated valve (76) the coil of which is in circuit with a pressure switch (77) replacing valve 72. The compressor motor contactors (81) are in parallel with a time delay relay operating a switch in the coil circuit. In Fig.3 (not shown), the valves (37, 76) of (Fig. 2) are replaced by a solenoid operated valve (176) serving to connect chamber 29 alternately to chamber 28 and to the output of valve 52. The coil of valve (176) is in a circuit identical to that of (Fig. 2). The compressors may be screw-type and, if a single stage compressor is used, line 56 communicates with the output duct. |
