Material leaves the head pulley when the centrifugal force needed to keep it on the belt exceeds gravity's component pulling it inward. Measuring the leave angle φ from the top of the pulley (in the direction of travel):
cos φ = v² / (g·R) — low-speed discharge (v² < gR)
φ = 0 — high-speed discharge (v² ≥ gR), leaves at the top
From that point the stream follows a free-fall parabola until it strikes the chute plate. The impact point is found by intersecting the parabola with the chute line; the impact speed feeds the readout above.
Once on the chute, material either keeps sliding or stalls, governed by the balance between gravity's component along the slope and friction resisting it:
a = g·(sin θ − μ·cos θ)
If the chute angle θ is less than the material's friction (angle-of-repose) angle φf = atan(μ), the deceleration is negative and the stream stalls partway down and piles up — the classic transfer-chute blockage. A small safety margin above φf is what "minimum chute angle" reports; industry chute design (CEMA guidelines) adds roughly 10–15° over the material's friction angle for exactly this reason.
- Belt speed / pulley radius — set where on the pulley the material actually leaves, and how far/fast it is thrown.
- Chute angle / material — set whether gravity wins against friction on the slope.
- Pile-up — rises whenever particles stall on the chute instead of sliding through; a full bar means the chute is jamming.