Steam trap (Hoard & Wiggin's patent)
Steam trap for shutting in steam, but providing for the escape of water from steam coils and radiators (Hoard & Wiggin’s patent). It consists of a box, connected at A with the end of the coil or the waste-pipe, having an outlet at B, and furnished with a hollow valve, D, the bottom of which is composed of a flexible diaphragm. Valve is filled with liquid, and hermetically sealed, and its diaphragm rests upon a bridge over the outlet-pipe. The presence of steam in the outer box so heats the water in valve that the diaphragm expands and raises valve up to the seat, a, a. Water of condensation accumulating reduces the temperature of valve; and as the liquid in valve contracts, diaphragm allows valve to descend and let water off.
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
- In section, as Brown, gravity on. A box (12 cm across) fed at A from the coil (steam at 2 kPa gauge, with its condensed water), its outlet B through a seat in a bridge; the hollow valve D on a slide, its sealed capsule a gas node of the vessels model with a heat store (openspec add-vessel-heat: C dT/dt = Q - H (T - T_amb), and the capsule's pressure follows its temperature). The steam cock at A is the only input (swung open and shut, 0.125 Hz): steam in the box heats the capsule (Q up to 160 W), the gas in it expands and its pressure on the diaphragm lifts D onto the seat; with the cock shut the capsule cools, its pressure falls and D drops, letting the water off.
- Measured
- Two full cycles: hot (over 350 K) the valve sits on its seat (lift over 0.39 cm, seat flow under 1e-4) and shuts the steam in; cool again (under 296 K) it drops (lift under 0.02 cm) and the water drains through B (tests/test_vessel_heat.py, mass conserved). The motion gate passes with no flags.
- Notes
- Grade B. The heat is not drawn (only its effect on the valve); the diaphragm is lumped into the capsule's piston.
Film (MP4) · Still (PNG) · Spec (YAML) · Model (MJCF)
