| 摘要 |
1,001,408. Measuring fluid flow. PNEUMATIC COMPONENTS Ltd, Jan. 3,1964 [Jan. 4, 1963], No. 452/63. Heading G1R. [Also in Division F2] In apparatus for dispensing gas in predetermined measured quantities e.g. CO 2 for the hardening of foundry moulds and cores, a spring loaded main valve 6, in an inlet chamber 5, in unseated by a push rod 21 connected to a dou g piston diaphragm 13 having sides of unequal area, the larger of which is supplied from the inlet 5 via the tapered passage 27 and adjustable choke 28 of Specification 1, 001, 407, and the smaller supplied from the inlet 5 by an unrestricted passage 11. The larger side of the piston diaphram is connect ed directly to a chamber 35 of capacity which is variable upon manual displacement of a piston 41 therein and is connected, via an inner hose 37, to the nozzle 56 of a handgrip 55 from which it is discharged, to displace the piston diaphragm 13 to open the closure 6, by unseating spring seated closure 71 upon manual depression of a handgrip cap 64 which simultaneously, by entry of stem section 67 into passage 69, prevents discharge of fluid directly from the inlet 5 via closure 6, passages 7 and 52 and outer hose 39 connected to passage 59. Upon release of spring cap 64, fluid from the inlet 5 is discharged from the nozzle 56 until pressure within the chamber 35 and on the larger side of the piston disphragm 13 has built up sufficiently to overcome the effect of inlet pressure on the smaller side thereof and the piston diaphragm is displaced to permit the closure 6 to seat. The piston diaphragm is biased to the closure 5 opening position by a spring 14 to compensate for frictional resistances and manufacturing tolerances and a direct proportionality between cycle time and inlet pressure is obtained by calibration adjustment of the spring 14 tension and of the choke 28 at maximum and minimum operating pressures with the cylinder 35 at maximum capacity. |
