| 摘要 |
1,235,770. Metering pump. RHONEPOULENC S.A. March 27, 1969 [March 29, 1968], No. 16213/69. Heading F1A. A volumetric metering pump for accurately dosing small quantities of liquid comprises a pair of inter-connected plungers 8, 9, reciprocable in a pair of opposed parallel cylinders 5, 6, each having a conduit 48, 49, connectible through a valve 50 to an inlet duct 53 and an outlet duct 54, the valve being set to connect the inlet duct 53 to cylinder 5 and the outlet duct 54 to cylinder 6 while the plungers 8, 9 are moving to the left as seen in Fig. 1 and vice versa when the pistons are moving to the right. The plungers 8, 9 are connected to a member 10 slidable along a guide rod 11 and having a rack 16 engaged by a pinion 17 on the drive-shaft 18 of a motor 22 which drives the pinion 17 in a series of small pulses, the motor being reversed and the valve 50 switched between a pair of consecutive pulses when the member 10 trips one of a pair of micro-switches 14, 15 mounted on end supports 12, 13 of the guide rod 11. The valve 50, Fig. 3, which is operated by a pair of solenoids 29, 30, comprises a fixed member 51 and a slidable member 52 with an interposed gasket 57. The member 52 has a pair of passages 58, 59 connected to the inlet 53 and outlet duct 54 respectively, and the member 51 has three passages 60, 61, and 62 the passages 60 and 62 being connected to conduit 49 and passage 61 being connected to conduit 48, the member 52 being positioned so that passages 58 and 59 align with passages 60 and 61 or 61 and 62 respectively. |
