The Z446-750-A250 is the 250 mL flat-bottom bottle insert for the Hermle Z446-750-BUK round bucket on the Z446-750-AC 4-place swing-out rotor (Z446 / Z446-K chassis) — sold as a 2-pack. Each insert holds 1 × 250 mL flat-bottom bottle; the 4-bucket rotor configuration takes 2 packs (4 inserts) for full symmetric loading, delivering 4 × 250 mL bottles per cycle (1 L total) in swing-out geometry. Per the universe price-list label, this insert is dimensioned for the flat-bottom 250 mL bottle envelope; the sister Z446-750-A250F SKU is dimensioned for the Falcon-conical 250 mL bottle envelope (the F suffix on the swing-out side denotes Falcon per Fred 2026-05-05, not "flat" — confirm envelope by SKU at order).
Naming-convention note: On the Z446-750 swing-out side, the F suffix denotes Falcon (Corning's conical bottle brand), so A250F = Falcon-conical and A250 = flat-bottom (this SKU). Per Fred 2026-05-05. The Z446-500 angle family uses the F suffix differently (per universe, A250F = flat on the angle side). Confirm bottle envelope by SKU at order.
Key Specifications
| SKU | Z446-750-A250 |
| Type | Bottle insert — 1 × 250 mL flat-bottom |
| Pack quantity | 2 inserts per SKU (full 4-bucket configuration takes 2 units = 4 inserts) |
| Per-insert capacity | 1 × 250 mL flat-bottom bottle |
| Per-cycle throughput (full configuration) | 4 × 250 mL = 1,000 mL total per cycle |
| Bottle format | 250 mL flat-bottom (per universe label and brochure dimensions in the Z446-750-BUK adapter table) |
| Compatible bucket | Z446-750-BUK (round bucket; with Z446-750-LID PC-Screw cap for sealable mode) |
| Compatible rotor | Z446-750-AC (4-place swing-out rotor body) |
| Compatible chassis | Z446, Z446-K (refrigerated), and -E voltage variants |
| Max. operating speed (with insert + bottle) | Per Z446-750-AC spec — 4,000/4,500 rpm at 3,434–4,346 × g maximum |
| Max. radius | 19.2 cm |
| Temperature at max speed (refrigerated chassis) | 4 °C |
| Geometry | Swing-out (0–90°) — flat sediment surface |
| List price | $572 (2-pack) |
Compatibility & When to Order This SKU
Insert pairing — Z446-750-BUK round bucket only. Order this SKU when:
- Adding 250 mL flat-bottom bottle workflow on the swing-out platform — order 2 units for full 4-bucket symmetric loading (1 L total per cycle).
- Cold-chain swing-out 250 mL flat-bottom bottle prep — when the workflow benefits from swing-out flat-sediment geometry for downstream supernatant aspiration in 250 mL flat bottles.
- Mixed Z446-750 swing-out workflow consolidation — when the lab uses the same chassis for clinical-blood prep at smaller volumes AND occasional 250 mL bottle workflows.
- Optional BSL-2 + workflow with the Z446-750-LID engaged.
- Replacement inserts if a current set is damaged or worn.
Swing-Out vs Angle 250 mL Workflow Choice
The Z446 / Z446-K chassis offers two rotor systems for 250 mL bottle workflows:
| Rotor system | Max RCF | Geometry | Per cycle |
| Z446-750-AC + Z446-750-A250 / A250F (swing-out, this insert family) | 4,346 × g | Swing-out flat-sediment | 4 × 250 mL |
| Z446-04500 + Z446-500-A250 / A250F (angle) | 10,367 × g | Fixed-angle 24° | 4 × 250 mL |
Per-cycle throughput is the same (4 bottles); the choice depends on whether the workflow needs swing-out flat-sediment geometry (this swing-out path) or higher RCF (the angle-rotor path).
Application Profile
Cold-chain swing-out bulk-volume bottle prep at 250 mL flat-bottom — vaccine-development and bioprocess workflows that batch 4 × 250 mL flat bottles per cycle with cold-chain integrity and flat-sediment geometry.
Mid-volume cell harvest in 250 mL flat-bottom — pelleting cells from suspension culture batches in flat-bottom bottle format where the wider base distributes the pellet across a larger surface area.
Organic-extraction phase separation in 250 mL flat-bottom glass — when the workflow includes phase separation in 250 mL working volume and the flat-base geometry supports clean phase boundaries.
Cold-chain mid-volume protein-prep workflows in flat-bottom format — TCA, ammonium-sulfate, organic-precipitation in 250 mL flat-bottom on the cold-chain refrigerated chassis.
Recombinant-protein bulk prep workflows in 250 mL flat-bottom — recombinant-protein expression and harvest in 250 mL flat-bottom bottle format on the swing-out platform.
Cross-format Z446-K core facilities — labs running 250 mL flat-bottom alongside other Z446-750 insert formats benefit from the cross-format insert family.
Ordering & Configuration
4-bucket symmetric loading. All 4 buckets must use matching A250 inserts for symmetric balance.
Bottle cap confirmation. All bottles must be capped securely before spinning at 4,500 rpm — at 250 mL working volume, sample loss from a cap failure represents substantial sample volume.
Bottle volume balance. When the 4 bottles carry different sample volumes, pre-balance pairs by total mass before spinning.
Optional hermetic-seal engagement. When using the Z446-750-LID for biosafety workflows, confirm the lid is fully threaded onto each bucket before each spin.
Z446-750-A250 ships as 2 inserts. Bottles (250 mL flat-bottom) are operator-supplied.
Confirm bottle envelope at order — this is the flat-bottom 250 mL bottle insert; the sister A250F is Falcon-conical (F = Falcon per Fred 2026-05-05). Confirm at quote: bucket pairing (Z446-750-BUK in inventory; Z446-750-LID if biosafety required), chassis pairing (Z446 or Z446-K) and power configuration, bottle format (250 mL flat-bottom for this A250), pack count (2 packs for full 4-bucket configuration), and lead time.
Warranty: 5-Year Hermle warranty (3 years full + 2 years drivetrain) on the inserts.
Z446-750 250 mL insert pair (Z446-750-AC swing-out rotor):
- Z446-750-A250 (this product) — 250 mL flat-bottom bottle
- Z446-750-A250F — 250 mL Falcon-conical bottle (F suffix = Falcon per Fred 2026-05-05)
Match the insert to the workflow's bottle envelope geometry. Confirm by SKU at order.
