Double-acting pump
Double-acting pump. Cylinder closed at each end, and piston-rod passes through stuffing-box on one end, and the cylinder has four openings covered by valves, two for admitting water and like number for discharge. A is suction-pipe, and B discharge-pipe. When piston moves down, water rushes in at suction-valve, 1, on upper end of cylinder, and that below piston is forced through valve, 3, and discharge-pipe, B; on the piston ascending again, water is forced through discharge-valve, 4, on upper end of cylinder, and water enters lower suction-valve, 2.
Only the input is driven; every other part of this model moves by physics (MuJoCo), and its ratios are measured. Run it live, change its parameters, or switch the friction off to see the output stop.
- Modelled as
- Seen in section, as Brown. The piston is the only drive (a slide, ±3 cm, 0.27 Hz). The cylinder is closed at both ends; the rod leaves through a stuffing box on the cover. The walls are cored as in the figure. Suction passage A rises on the right from a well; discharge passage B rises on the left and leaves the picture at the top. Four flaps hang by their top edges in partitions at the heads: 1 (top) and 2 (bottom) admit from A, 4 (top) and 3 (bottom) discharge into B. Each flap is moved only by its weight and the pressures on its faces. Water is lumped vessels: A, the space under the piston, the space over it (less the rod), and B are full chambers. The piston sweeps both. A and B are inertial pipes; B delivers 60 cm up, beyond the frame. All passages and heads are drawn full from the chambers, and the streams in A and B show the flow. gen: opencode-runs/water/gen452.py
- Measured
- Trace over 6–12 s: on the down-stroke flaps 1 and 3 open fully (0.9 rad) while 2 and 4 stay shut; on the up-stroke 2 and 4 open while 1 and 3 stay shut, as Brown describes. Each flap passes up to about 460 g/s. Delivery up B runs on both strokes (mean 280 g/s, peak 472) and stops only at each reversal; suction matches (mean 280 g/s). The under-piston pressure swings about −3.9 to +12.7 kPa and the over-piston pressure about −4.7 to +9.1 kPa. A brief backflow (≤30 g/s) passes each flap as it shuts. Gate: pytest 2 passed, lint 0 FAIL, motion gate pass, no WARN.
- Notes
- Grade B+. Not in Brown: the delivery height beyond the frame, the drive speed, and the well (Brown breaks A off). The flaps swing to a 0.9 rad stop, which reads larger than Brown's sketch. Flap placement is my reading of the figure: 1 and 2 on A's side, 3 and 4 on B's. The cylinder sits inside the passages in plain boxes rather than Brown's rounded casting.
Film (MP4) · Still (PNG) · Spec (YAML) · Model (MJCF)
