Dry gas meter
Dry gas meter. Consists of two bellows-like chambers, A, A', which are alternately filled with gas, and discharged through a valve, B, something like the slide-valve of a steam engine, worked by the chambers, A, A'. The capacity of the chambers being known, and the number of times they are filled being registered by dial-work, the quantity of gas passing through the meter is indicated on the dials.
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 from in front, the chambers cut away in half section, gravity on. Two chambers, A above the shaft and A′ below it (12 cm bore), are each closed by a moving board on a rod to a crank of one shaft. The cranks stand a quarter turn apart. The main's pressure (300 Pa, the only input; no torque on the shaft) fills and empties the chambers through slide valves B and B′. Each valve is worked by an eccentric on the same shaft, so the chambers work their own valves. Each board's other side is also a measuring space, so the chambers are double-acting. All four spaces are lumped gas vessels swept by their boards (pistons), and the valve ports are links that open with the valve's travel.
- Measured
- The shaft turns steadily at about 1.6 rad/s, driven only by the gas. One side of each board fills while the other side empties to the burners, and the valves change them over at the end of each stroke. Each turn passes a known volume (about 4.5 L). All four gas spaces are drawn and shaded by their pressure. The motion gate passes.
- Notes
- Grade B. Departures from Brown's figure: Brown's one valve is drawn as two (B and B′); the chambers are double-acting; a small fly on the shaft stands in for the dial-work's train, which is not modelled. Reframed (camera lower, wider) so the base clears the title. Gate WARNs: 28% unexplained motion is the gas shading; no water is expected for a gas movement.
Film (MP4) · Still (PNG) · Spec (YAML) · Model (MJCF)
