The Z446-750-A50R is a 7-position 50 mL round-bottom tube 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 7 × 50 mL round-bottom tubes; the 4-bucket rotor configuration takes 2 packs (4 inserts) for full symmetric loading, delivering 28 × 50 mL round-bottom tubes per cycle (1.4 L total) in swing-out geometry.
Key Specifications
| SKU | Z446-750-A50R |
| Type | Tube insert — 7 × 50 mL round-bottom |
| Pack quantity | 2 inserts per SKU (full 4-bucket configuration takes 2 units = 4 inserts) |
| Per-insert capacity | 7 × 50 mL round-bottom tubes |
| Per-cycle throughput (full configuration) | 28 × 50 mL round-bottom = 1,400 mL total per cycle |
| Tube format | 50 mL round-bottom glass or polypropylene (29 mm OD, 102–123 mm length range) |
| 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 + tubes) | Per Z446-750-AC spec — 4,000/4,500 rpm at 3,434–4,346 × g maximum |
| Max. radius | 19.2 cm (0.2 cm radius correction with this insert) |
| Temperature at max speed (refrigerated chassis) | 4 °C |
| Geometry | Swing-out (0–90°) — flat sediment surface |
| List price | $489 (2-pack) |
Compatibility & When to Order This SKU
Insert pairing — Z446-750-BUK round bucket only. Order this SKU when:
- Adding 50 mL round-bottom workflow at higher throughput to an existing Z446 / Z446-K + Z446-750 install — order 2 units for full 4-bucket symmetric loading (28 tubes/cycle, 1.4 L total).
- Cold-chain 50 mL round-bottom prep at scale — refrigerated cell-culture pellet recovery, biobank intake, density-gradient prep at 28 tubes per cycle.
- Glass round-bottom 50 mL workflows at scale — when the protocol requires glass for organic-solvent compatibility, repeated autoclave reuse, or precise volume measurement.
- Optional BSL-2 + workflow with the Z446-750-LID engaged.
- Replacement inserts if a current set is damaged or worn.
Round-Bottom vs Conical — Choosing a 50 mL Insert
The Z446-750-AC swing-out rotor serves 50 mL in two tube formats, on two bucket types:
| Insert | Tube format | Bucket | Per cycle |
| Z446-750-A50R (this SKU) | 50 mL round-bottom | Z446-750-BUK round bucket | 28 |
| Z446-750-B50 | 50 mL conical | Z446-MP-BUK rectangular bucket | 28 |
Both inserts deliver 28 tubes per cycle. Pick the A50R for round-bottom 50 mL workflows on the round bucket; pick the B50 for conical 50 mL workflows on the rectangular bucket.
Application Profile
4-bucket symmetric loading. All 4 buckets must use matching A50R inserts for symmetric balance.
Per-insert symmetric loading. Within each insert, the 7 round-bottom tubes should be balanced symmetrically — pair tubes by mass with the seventh position symmetric to the insert's central axis.
Optional hermetic seal via LID. When combined with the Z446-750-LID, the bucket creates a hermetic envelope for BSL-2 + 50 mL round-bottom workflows.
Design Architecture
Cold-chain 50 mL round-bottom prep at institutional scale — patient sample fractionation, aliquot prep, biobank intake at 28 × 50 mL round-bottom per cycle on the cold-chain swing-out chassis.
Cold-chain glass-compatible 50 mL workflows at scale — organic-extraction, chemical-prep, and precipitation workflows in 50 mL round-bottom glass at refrigerated temperature, at higher per-cycle throughput.
Cell-culture pellet recovery in 50 mL round-bottom at scale — when cell-culture protocols specify round-bottom over conical and the workflow benefits from 28 parallel preps per cycle.
Density-gradient prep in 50 mL round-bottom at scale — Ficoll, Percoll, sucrose-gradient prep at 28 parallel preps per cycle on the cold-chain swing-out chassis.
Cold-chain protein prep in 50 mL round-bottom at scale — TCA, ammonium-sulfate, organic-precipitation in 50 mL round-bottom at 28 parallel preps with refrigeration.
Cross-format Z446-K core facilities — labs running 50 mL round-bottom at high throughput 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 A50R inserts. Mixed-bucket configurations produce mass asymmetry.
Tube cap confirmation. All 50 mL round-bottom tubes must be capped securely before spinning at 4,500 rpm.
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-A50R ships as 2 inserts. 50 mL round-bottom tubes (glass or polypropylene) are operator-supplied. The Z446-750-BUK bucket and (optional) Z446-750-LID are sold separately.
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, tube format (50 mL round-bottom; 50 mL conical uses the Z446-750-B50 rectangular-bucket insert), pack count (2 packs for full 4-bucket configuration = 28 tubes/cycle), and lead time.
Warranty: 5-Year Hermle warranty (3 years full + 2 years drivetrain) on the inserts.
Z446-750 50 mL inserts (Z446-750-AC swing-out rotor):
- Z446-750-A50R (this product) — 7 × 50 mL round-bottom on Z446-750-BUK round bucket (28/cycle)
- Z446-750-B50 — 7 × 50 mL conical on Z446-MP-BUK rectangular bucket (28/cycle)
Pick A50R for round-bottom 50 mL workflows; pick B50 for conical 50 mL workflows.
