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Aggregate Quarry & Mineral Comminution, Symons / Hydrocone Parallel-Zone Kinematics

Cone Crusher CSS, Eccentric Throw & Parallel-Zone Capacity

Calculate Open-Side Setting OSS (mm), Gravity Free-Fall Drop Per Half-Cycle (mm), Parallel-Zone Compression Hits, and Choke-Fed Volumetric Throughput (t/h).

Slowing a VFD cone crusher from 265 to 175 RPM boosts raw tonnage to 180 t/h—by letting uncrushed oversize slabs fall clear through the parallel zone in 1.15 hits!

**Secondary and Tertiary Symons / Hydrocone Gyratory-Cone Crushers** (`Mantle Base Diameter D` m, `Closed-Side Setting CSS` mm, `Full Eccentric Throw e` mm -> **Open-Side Setting `OSS = CSS + e`** mm) produce cubical asphalt/concrete aggregate ONLY when rock fragments receive **`>= 2.0–3.0` interparticle compression nips** inside the lower **Parallel Sizing Zone (`Length L_p` mm)**! During the `t_{fall} = 30 / N` (`seconds`) retreating half-revolution at Eccentric Speed `N` (`RPM`), gravity accelerates rock downward by **Free-Fall Stroke `s_{drop} = (0.5 * g * (30 / N)^2) * 1,000`** (`mm`), giving **Parallel-Zone Compression Events `n_{hits} = L_p / s_{drop}`** and **Choke-Fed Ribbon Throughput `Q = 0.42 * pi * D * ((CSS + e / 2) / 1,000) * (s_{drop} / 1,000) * N * 60 * rho_b`** (`t/h` at Chamber Void/Swell Factor `0.42` and Bulk Density `rho_b` t/m³)! Turn VFD speed down too far (`175` RPM) and `s_{drop}` (`144.1` mm) nearly equals the entire `165` mm parallel zone (`1.15` hits)—flooding recycle screens with flaky `OSS`-sized (`55` mm!) slabs!

Verify on a `1,520` mm (`5`-ft) Secondary Standard Cone Crusher—Mantle_Base_Diameter `D` = 1.52 m (B2), Closed_Side_Setting `CSS` = 19.0 mm (B3), Eccentric_Throw `e` = 36.0 mm (B4), Eccentric_Speed `N` = 265 RPM (B5), Parallel_Zone_Length `L_p` = 165 mm (B6), and Loose_Ore_Bulk_Density `rho_b` = 1.60 t/m³ (B7): Open-Side Setting `OSS` equals `55.0` mm (E2), Half-Cycle Free-Fall Drop equals `62.84` mm (E3), Parallel-Zone Compression Hits equal **`2.63`** (`>= 2.0` cubical product! E4), and Choke-Fed Capacity equals `118.6` t/h (E5)!

Cone Crusher Kinematics KPI (D=1.52 m, CSS=19 mm, Throw=36 mm, Lp=165 mm)FormulaVerified Output
Open-Side Setting OSS (mm)Closed_Side_CSS_mm + Eccentric_Throw_e_mm55.0 mm
Half-Cycle Free-Fall Drop (mm)(0.5 * 9.80665 * ((30 / RPM) ^ 2)) * 100062.84 mm (144.10 mm @ 175 RPM!)
Parallel-Zone Nip HitsParallel_Zone_L_mm / Free_Fall_Drop_mm2.63 CUBICAL (1.15 SLAB BYPASS!)
Choke-Fed Throughput (t/h)0.42 * PI * D * MeanGap * Drop * RPM * 60 * rho118.6 t/h graded (179.6 t/h ungraded!)

Symons / Svensson Cone Crusher Free-Fall Ribbon & Parallel-Zone Hit Formula

Validate `Mantle_Diameter D` in `[0.6, 3.2]` m, `CSS` in `[4, 75]` mm, `Eccentric_Throw e` in `[10, 90]` mm, `Eccentric_Speed N` in `[140, 450]` RPM, `Parallel_Zone L_p` in `[50, 450]` mm, and `Bulk_Density` in `[1.1, 3.2]` t/m³!

=LET(dm_m, B2, cs_m, B3, th_m, B4, nr_p, B5, lp_m, B6, rb_t, B7, dp_m, 0.5 * 9.80665 * ((30 / nr_p) ^ 2), IF(OR(dm_m < 0.6, dm_m > 3.2, cs_m < 4, cs_m > 75, th_m < 10, th_m > 90, nr_p < 140, nr_p > 450, lp_m < 50, lp_m > 450, rb_t < 1.1, rb_t > 3.2), "Invalid Cone Input", ROUND(0.42 * PI() * dm_m * ((cs_m + th_m / 2) / 1000) * dp_m * nr_p * 60 * rb_t, 1)))

Under-Speed VFD Operation (`N = 175` RPM) Oversize Circulating-Load Surge Check

Slow the countershaft drive so eccentric speed drops to `B5 = 175` RPM: Free-Fall Drop E3 jumps to **`144.10` mm**, slashing Parallel-Zone Hits E4 to **`1.15`** while apparent chamber discharge E5 climbs to **`179.6` t/h**—nearly half of which bounces right off the `22` mm closing screen back into the crusher bowl!

=IF(ISTEXT(E5), E5, LET(dp_m, (0.5 * 9.80665 * ((30 / B5) ^ 2)) * 1000, ROUND(B6 / dp_m, 2)))

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